A MANUAL OF CHEMICAL ANALYSIS AS APPLIED TO THE EXAMINATION OF MEDICINAL CHEMICALS. A GUIDE FOR THE DETERMINATION OF THEIR IDENTITY AND QUALITY, AND FOR THE DETECTION OF IMPURITIES AND ADULTERATIONS. FOB THE USE OF PHARMACISTS, PHYSICIANS, DRUGGISTS, MANUFACTURING CHEMISTS, AND PHARMACEUTICAL AND MEDICAL STUDENTS. THIRD EDITION, THOROUGHLY REVISED AND GREATLY ENLARGED. FREDERICK HOFFMAKK, A.M.,Ph.I BY TIT- PUBLIC ANALYST TO THE STATE OF NEW YORK, ETC., FREDERICK B. POWER, Pu.D., AND PROFESSOR OF ANALYTICAL CHEMISTRY IN THE PHILADELPHIA COLLEGE OF PHARMACY. PHILADELPHIA: HENRY C. LEA’S SON & CO 1888. Entered according to Act of Congress, in the year 1883, by HENRY C. LEA’S SON & CO., in the Office of the Librarian of Congress. All rights reserved COLLIN S, PRINTER. PREFACE TO THE THIRD EDITION. The third edition of this work has been thoroughly revised and to a large extent re-written, in order to make it comply with the present compass of chemical knowledge, as also with the recently issued new editions of the Pharmacopoeias of the United States of America and of the German Empire. The general and original plan and character of the work have been retained; the first part has been much enlarged, so as to afford an explicit and comprehensive guide and work of reference to both student and expert. All the articles of the second part have been carefully revised and greatly enlarged, many new ones added, as also the most approved methods for the sepa- ration, identification, and, in most cases, for the quantitative estimation of the chemical poisons likely to be met with in foren- sic research. As in former editions, the aim has been to render each article complete in text and illustrations, so as to avoid, as far as possible, references to other articles. The German, French, and Spanish names have been added, as also a large number of new illustra- tions of apparatus and forms of crystals. The senior author desires to express his obligations and thanks to his friend and associate Dr. Frederick B. Power, to whose efficient and able assistance all credit for the superiority of the present edition is due. New York, February, 1883. PREFACE TO THE FIRST AND SECOND EDITIONS. Although the preparation of most medicinal chemicals has passed away from the laboratory of the pharmacist, and is sue cessfully conducted on a commercial scale in manufacturing estab- lishments, yet the responsibility for the identity and quality of medicines, and of the substances used in their preparation, rests properly and legally with those who prepare, compound, and dis- pense them. It is therefore the duty of the pharmacist and the dispensing practitioner of medicine, as also, to a considerable extent, of the druggist and the manufacturing chemist, to examine the medicinal chemicals of commerce as to their identity, quality, and purity. In the exercise of this duty, they have frequent occasion to resort for information to references now widely scat- tered through chemical, pharmaceutical, and medical manuals and journals; since our literature, although of vast and increasing extent, and crystallizing more and more into distinct branches, is still wanting in a special guide for ready reference in the applica- tion of chemical analysis to such examinations. In the present volume I have endeavored to supply this want, in a manner and to an extent which, it is hoped, will coniine the work within the precise limits of requirement, without detracting from its general scope and its practical usefulness. Since chemical tests and examinations bear upon and involve the methods of systematic chemical analysis, and as these cannot be described in each particular instance, I have deemed it expe- dient to preface the volume with a few notes on operations and reagents, and on a few important general tests, and to present a VI PREFACE TO THE FIRST AND SECOND EDITIONS. brief outline of a simple course of qualitative analysis for the sys- tematic and progressive recognition of such substances as are met with in the medicinal chemicals. A brief guide has also been added for the volumetric estimation of those compounds to which this mode of examination is especially applicable. Upon these preliminaries is based the subsequent description of the physical and chemical properties and relations of the medici- nal chemicals and their preparations, and of the methods em- ployed for establishing their identity, and for ascertaining their quality and purity. It has been compiled with special reference to the recent editions of the Pharmacopoeias of the United States, of Great Britain, and of Germany, and has been brought within the briefest possible compass, with the view to furnish a concise and trustworthy guide, combining easy execution, simple appa- ratus, and economy of time, with the greatest attainable accuracy. In preparing this compendium, I have consulted, and at times made free use of, a number of standard works, and periodicals of the kindred literature. I have, however, felt compelled, not with- out hesitation, to omit the introduction of references, which would have required much space, and would have greatly increased the size of the volume, without affording a corresponding advantage. Though well aware of the shortcomings and imperfections of the work, I nevertheless venture to hope that it will meet with kind consideration, and will prove both serviceable and stimulat- ing in a province not yet duly appreciated or deservedly culti- vated. This hope is the stronger, as the work appears at a time when the rapid advance of both sciences and arts, the drift of public sentiment, and the consequently increasing obligations of the pharmaceutist and the physician, all tend toward higher quali- fications, and necessitate also, among other attainments, a more extended exercise of knowledge and skill in chemical and micro- scopical investigation. New York, February, 1873. CONTENTS. PART FIRST PAGE Operations . . . . . . . .17 Reagents ......... 2G Reagents and Test Solutions . . . . .29 Course of Qualitative Analysis . . . . .43 Preliminary Examination . . . . . .44 Solution ........ 4g Examination for Bases . . . . . .49 Examination for Acids . . . . . .61 Table of the Deportment of the Compounds of the Principal Metals with some of the General Reagents . . . . .69 Volumetric Analysis .... ... 70 Analysis by Neutralization . . . . . .80 Estimation of Alkalies . . . . . .80 Estimation of Acids . . . . . .86 Analysis by Oxidation and Reduction . . . .88 Estimation of Sugars . . . . . .96 Analysis by Precipitation . . . . . .98 Alkaloids . . . . . . . .102 PART SECOND. MEDICINAL CHEMICALS AND THEIR PREPARATIONS. Acetum . . . . . . . . .117 Acidum Aceticum . . . . . . .122 P Arseniosum . . ; . . . .126 Detection of Arsenic in Forensic Investigation . . 132 Detection of Arsenic in Coloring-matters, Paper, and Fabrics 134 “ Benzoicum . . . . . .135 “ Boricum . . . . . . . .137 “ Carbolicum . . . . . ■ . .139 “ Chromicum . . . . . . .142 “ Citricum ........ 144 “ Gallicum . . . . . . . .147 “ Hydriodicum ....... 148 CONTENTS. PAGE Acidum Hydrobromicum . . . . . . .150 “ Hydrochloricum . . . . . . .153 “ Hydrocyanicum ....... 150 Detection of Hydrocyanic Acid in Forensic Investigation . 161 “ Hypophosphorosum . . . . . . 163 “ Lacticum ...... 164 “ Nitricum . . . . . . . .165 “ Oleicum . . . . . . .171 “ Oxalicum . . . . . . .172 “ Phosphoricum . . . . . . .174 “ Salicylicum . . . . . . .181 “ Succinicum . . . . . . .182 “ Sulpliuricum . . . . . . .184 “ Sulphurosum . . . . . . .190 “ Tannicum . . . . . . . .192 “ Tartaricum . . . . . . .195 “ Valerianicum . . . . . .197 Aconitina ......... 200 ./Ether ......... 201 ASther Aceticus ........ 204 Alcohol ......... 206 Alcohol Amylicum ... ... 210 Aloinum . . . . . . 1 . .211 Alumen . . . . . . . . .212 Detection of Alum in Flour and Bread .... 214 Aluminii Hydras . . . . . . . .214 “ Sulphas . . . . . . . .2-16 Ammonii Benzoas . . . . . . . .217 “ Bromidum ...... 217 “ Carbonas . . .. . . . .221 “ Chloridum ....... 223 “ Iodidum ........ 225 “ Nitras ........ 226 “ Phosphas ....... 227 “ ■ Sulphas ........ 228 “ Yalerianas . . . . .. . 229 Amyl Nitris ........ 230 Antimonii et Potassii Tartras . . . . . ._ 232 “ Oxidum ....... 235 “ Sulpliidum . . . . . . .237 “ “ Aurantiaeum ..... 240 Antimonium Sulphuratum . . . . . . 242 Apomorphinae Hydrochloras ...... 245 Aqua Ammonia; ........ 245 “ Amygdala; Amaras ...... 249 4‘ Chlori ........ 251 “ Destillata ........ 254 CONTENTS IX PAGE Argenti Cyanidum ........ 256 “ Iodidum . . . . . . . .257 “ Nitras ........ 258 “ Oxidum . . . . . . . .261 Arsenii Bromidum . . . . . . . .262 “ Iodidum ........ 263 Atropina ......... 263 Atropinae Sulphas ........ 265 Auri et Sodii Chloridum ....... 266 Barii Chloridum . . . . . . . .268 Benzinum ......... 269 Bismuthi Citras . . . . . . . .270 “ et Ammonii Citras ...... 272 “ Subearbonas . . . . . . .273 “ Subnitras . . . . . . .276 “ Yalerianas . . . . . . .277 Bromum ......... 279 Brucina . . . . . . . . 282 Cadmii Iodidum . . . . . ... . 284 “ Sulphas ........ 285 Caflf'eina . . ... . . . . . 286 Caleii Bromidum . . . . . . . .287 “ Carbouas prseeipitatus . . . . . .289 “ Chloridum ... . . . . . . 290 “ Hypophosphis . . . . . . .292 “ Iodidum ........ 293 “ Phosphas prsecipitatus ...... 294 Calx Chlorata ........ 296 “ Sulphurata ........ 299 Camphora monobromata ....... 300 Cantharidinum ........ 300 Carbonei Bisulphidum . . ... . . . 301 Cerii Oxalas ........ 303 Chinoidinum . . . . . . . 304 Chloral . . . . . . . . .305 Chloralum Butylicum ....... 308 Chloroformum ........ 308 Chrysarobinum . . . . . . . .312 Cinchonidina . . . . . . . .313 Cinchonidinae Sulphas . . . . . . .314 Cinchonina . . . . , . . .315 Cinchoninae Sulphas . . . . . . .317 Codeina . . . . . . . .318 Colchicina . . . . . . . . .320 Coniina ......... 322 Creasotum . . . . . . . . .324 Cupri Aeetas ........ 326 X CON TENTS. PAGE Cupri Oxidum ....•••• 329 “ Sulphas 330 Cuprum Ammoniatum . • • • • • 332 Curarina 333 Digitalinum ....•••• 334 Elaterinum . . • • • • • -337 Emetina 338 Ferri Arsenias ..■••••• 339 “ Carbonas Saccharatus ...... 340 “ Chloridum 341 “ Citras ....•••• 343 “ et Ammonii Chloridum ...... 344 “ “ “ Citras . . . • • • .345 “ “ Sulphas . . ■ • - • -346 “ “ “ Tartras . . . - • • .346 “ “ Potassii Tartras . . . • • • .347 “ “ Quinin® Citras ....... 348 “ “ Strychnin® Citras 349 “ Ferrocyanidum . • • • • • .350 “ Hvpophosphis ....... 352 “ Iodidum ........ 352 “ Lactas ........ 353 “ Oxalas ........ 355 “ Oxidum Hydratum ....... 356 “ Phosphas ........ 357 “ Pyrophosphas ....... 359 “ “ et Sodii Citras ..... 359 “ Subcarbonas ........ 360 “ Sulphas . . . • • • .361 “ Yalerianas ........ 363 Ferrum ......... 364 Glycerinum . . • • • • • .370 Detection and estimation of glycerin in beverages . . .372 Hydrargyri Chloridum corrosivum . . . • • .373 “ “ mite . . . • • .375 “ Cyanidum . . . • • - . - 378 “ Iodidum rubrum . • • • • .379 “ “ viride ...... 381 “ Oxidum fiavum ...... 382 “ “ rubrum ...... 382 “ Subnitras ....... 385 “ Subsulphas flavus ...... 386 “ Sulphidum rubrum . . . . . .386 Hydrargyrum 388 “ ammoniatum ...... 390 Hyoscyamin® Sulphas ....... 392 Iodoformum . . * • • • • 392 CONTENTS. PAGE Iodum ......... 393 Liquor Ammonii Acetatis ....... 397 “ Antimonii Chloridi . . . . . . .397 “ Calcis . . . . . . .399 “ Ferri Acetatis ....... 399 “ “ Chloridi ....... 401 “ “ Citratis . . . . . . . 402 “ “ et Quininae Citratis . . . . . . 403 “ “ Nitratis ....... 404 “ “ Sulphatis ....... 405 “ Hydrargyri Nitratis ...... 406 “ Plumbi Subacetatis . . . . . .407 “ Potassae ........ 408 “ Potassii Arsenitis . . . . . . .410 “ Sodae . . . . . . . .412 “ “ Chloratae . . . . . .414 Lithii Benzoas . . . . . . .415 “ Bromidum ........ 416 “ Carbonas . . . . . . . .417 “ Citras . . . . . . . .419 “ Salicylas . . . . . . . 420 Magnesia ......... 421 Magnesii Carbonas . . . . . . . .422 “ Sulphas ........ 423 “ Sulphis ........ 426 Mangani Oxidum nigrum . . . • . . . 426 “ Sulphas ........ 429 Morphina ......... 430 Morphinae Acetas . . . . . . . 432 Morphinae Hydrochloras ....... 433 “ Sulphas ........ 434 Morphiometric Assay of Opium ..... 435 “ “ Tincture of Opium . . . 439 Nicotina ......... 439 Oleum Amygdalae aethereum ...... 440 “ Sinapis aethereum ....... 443 Phosphorus ......... 445 “ Detection of phosphorus in forensic investigation . . 446 Physostigminae Salicylas ....... 449 Picrotoxinum ..... . . 449 Pilocarpinae Hydrochloras ....... 45] Piperina ......... 45] Plumbi Acetas ........ 452 “ Carbonas ........ 453 “ Iodiduin ........ 455 “ Nitras ........ 456 “ Oxidum . . . . . . . .457 CONTENTS PAGE Plurnbi Oxidum rubrum ....... 458 Potassa Sulphurata ........ 459 Potassii Acetas . . . . . . . .460 “ Bicarbonas ...... 462 “ Bicbromas ........ 464 “ Bitartras ........ 465 “ Bromidum . . . . . . . .467 “ Carbonas Cnidus \ ..... 470 “ “ Depuratus . . . . . .473 “ “ Purus . . . . . . .475 “ Chloras . . . . . . . .478 “ Citras ........ 479 “ Cyanidum ........ 481 “ et Sodii Tartras ....... 483 “ Ferrocyanidum ....... 485 “ Hydras ........ 486 “ “ crudus ....... 488 “ Hypophosphis . . . . . . 490 “ Iodidum . . . . . . . .491 “ Nitras ........ 494 “ Permanganas . . . . . . .497 “ Sulphas ........ 498 “ Sulphis ........ 499 “ Tartras ........ 501 Quinidina ......... 502 Quinidinae Sulphas . . . . . . . . 503 Quinina ......... 505 “ estimation of the alkaloids in Cinchona bark . . .507 Quininae Hydrobromas . . . . . . .515 “ Bisulphas . . . . . . . .516 “ Hydrochloras . ; . . . . .518 “ Sulphas ......... 520 “ Tannas . . . . . . .523 “ Yalerianas. ....... 525 Resorcinum ......... 526 Salicinum . . . . . . . . .. 527 Santoninum ........ 528 Sodii Acetas ........ 530 “ Arsenias ........ 532 “ Benzoas ........ 533 “ Bicarbonas ........ 534 “ Bisulphis . . . . . . . .537 “ Boras . ... . . . . . . 538 “ Bromidum ........ 539 “ Carbonas ........ 543 “ Chloras ........ 546 “ Chloridum ........ 548 CONTENTS. PAGE Sodii Hydras ........ 550 “ Hypophosphis ....... 552 “ Hyposulphis ........ 554 “ Iodidum ........ 556 “ Nitras . . . . . . . .560 “ Phosphas . . . . . . . .561 “ Pyrophosphas . . . . . . 564 “ Salicylas ........ 565 “ Santoninas ........ 566 “ Sulphas . . . . . . . .567 “ Sulphis ........ 560 “ Sulphocarbolas . . . . . . * 570 Spiritus iEtheris nitrosi . . . . . . .571 Strychnina ......... 574 Strychnin* Nitras . . . . . . . .576 “ Sulphas ....... 578 Sulphur Prascipitatum . . . . . . .578 “ Sublimatum ....... 581 Sulphuris Iodidum ........ 583 Thymol ......... 583 Veratrina ......... 584 Zinci Acetas ........ 586 “ Bromidum . . . . . . . .587 “ Carbonas Precipitatus ...... 588 “ Chloridum ........ 589 “ Iodidum ... . . . . . . 590 “ Oxidum . . . . . . . .591 “ Phosphidum ........ 593 “ Sulphas ........ 594 “ Sulphocarbolas . . . . . . .597 “ Yalerianas ........ 598 Table of Elementary Bodies, with their Symbols and Atomic Weights . 603 Table of Thermometric Equivalents, aecoi-ding to the Centigrade and Fahrenheit Scales .....:. 604 Table for converting Metric Measures of Capacity into United States Fluid Measures . . . . . . . 606 Table for converting United States Fluid Measures into Metric Measures of Capacity ........ 607 Table for converting Metric Weights into Troy Weights . . . 608 Table for converting Troy Weights into Metric Weights . . . 609> Index . . . . . . . . .611 PART I. OPERATIONS AND REAGENTS, INCLUDING AN OUTLINE OF A SYSTEMATIC COURSE OF QUALITATIVE CHEMICAL ANALYSIS, VOLUMETRIC ESTIMATION, AND A METHOD FOR THE SEPARATION AND RECOGNITION OF THE PRINCIPAL ALKALOIDS AND ALLIED PRINCIPLES. OPERATIONS AND REAGENTS. OPERATIONS. The operations involved in the application of simple tests and chemical examinations must be supposed to be familiar to the pharmacist, the druggist, the pharmaceutical or chemical manu- facturer, and the physician. For the student and the less experi- enced operator, however, the following preliminary explanations and descriptions relating to the more important simple operations are considered to be of sufficient practical value to merit a brief notice. Solutions,—With regard to the nature of the product, two kinds of solution are distinguished, simple and chemical. In a “simple solution” the dissolved body retains all of its original properties, with the exception of its physical form, and may be obtained again in its former state on the removal of the solvent by evapo- ration: for instance, solution of ferrous sulphate in water. It is “saturated” when the solvent ceases to take up any more of the dissolved body; but as the coefficient of solubility of most substances is increased by heat, the expression of saturation will therefore always relate to the temperature at which the solution has been formed. A “chemical solution” is one in which the dis- solved body no longer retains its original qualities, but, through the action of the solvent, has become converted into a new sub- stance, possessing variously modified chemical and physical prop- erties: for instance, solution of ferrous carbonate in dilute sulphuric acid. Solutions for testing are best prepared in test-tubes, or in small flasks or beaker-glasses. Increase of the surfaces of contact by comminution, agitation, and increase of temperature, as is well known, aid and accelerate the process of solution, as well as of chemical reaction ; and one or both of these auxiliaries may be employed, unless the nature of the substance or the effect of heat upon it is such as to exclude their application. The common solvent, wate*r, has to be used distilled, and this fact is to be understood throughout this work ; neither rain-water nor spring-water, however pure it may appear to be, can be used 18 MANUAL OF CHEMICAL ANALYSIS. indiscriminately as a solvent or for edulcoration in chemical in- vestigations. To effect the solution of substances insoluble in water, for the purpose of chemical examination, or where the aid of an acid is required, only such acids as are found by the operator himself to be chemically pure should be employed. Precipitation.—The formation of an insoluble body from a solu- tion can be effected either by a change or modification of the solvent, or by the production of one or more new bodies, insoluble in the solvent. An instance of the first case is an aqueous solution of barium chloride, which will be precipitated by the addition of concentrated hydrochloric acid, or a solution of calcium sulphate, which will be precipitated by alcohol; in both these instances the solvent power of the liquid is lessened, and solution may be re- established by the addition of a sufficient quantity of water. In- stances of the second case of precipitation are a solution of calcium hydrate precipitated by sodium carbonate, and a solution of mag- nesium sulphate precipitated by barium hydrate. Precipitation is resorted to as the most important mode of de- tecting and discriminating bodies by their physical and chemical properties, and of effecting their separation. According to the nature or appearance of the precipitates, they are variously dis- tinguished; thus “ flocculent,” when forming flock-like masses; “crystalline,” if, when magnified, the small particles are seen to be composed of minute but distinctly formed crystals; “gelatinous,” if jelly-like; or “curdy,” if separating in the form of a curd, etc. The terms “turbidity” and “cloudiness” designate the formation of a precipitate so insignificant in quantity, or so finely divided, or so light in weight, that the suspended particles only impair the transparency of the fluid, and require a certain amount of time to subside in the form of a precipitate. If the transparency of a colorless or nearly colorless liquid becomes so slightly impaired upon the addition of a reagent as not to become distinctly turbid, but displays a reflection of pearly light, and thus presents an opal-like appearance, the minute degree of precipitation thus produced is designated as “ opalescence.” Filtration and Decantation.—The separation of the supernatant liquid from a precipitate is effected either by filtration and subse- quent washing of the precipitate upon the filter by means of a wash-bottle (Figs. 1 and 2), or, where the precipitate speedily and completely subsides, by decantation. As a rule, funnels and filters must be small, and proportionate to the amount of the pre- cipitate and the liquid requiring filtration. Filters employed in analytical operations should be as free as possible from inorganic substances, especially such as become dis- solved by the action of acids, as calcium salts, ferric oxide, etc., and for the collection of precipitates should be smooth, so placed in the funnel as to fit closely on all sides, and cut so as not to OPERATIONS. 19 project over the rim; it is also advisable always to moisten the filter upon the funnel with distilled water, by means of the wash-bottle, previous to the collection of the precipitate, or to filtration. Fig. 1. Fig. 2. Decantation is effected either by pouring off the supernatant clear part of the fluid by simply inclining the vessel, and allowing Fig. 3. the fluid to flow down a glass rod (Fig. 8), or by drawing it off" by means of a small glass siphon or a pipette (Figs. 4 and 5). Washing Precipitates.—In either mode of separation the precipi- tate, in most instances, must be thoroughly freed from the ad- dering liquid by washing with water, either on the filter or by decantation. As a rule, the washing of precipitates is most thoroughly and quickly effected by means of hot water; for this purpose nothing more is required than the ordinary wash-bottle, 20 MAMJAL OF CHEMICAL ANALYSIS Fig. 4. Fig. 5. which, however, for convenience in holding, is provided either with a wooden handle, attached by means of a strong wire to the flask (Fig. 2), or the neck of the flask may be covered with a thick circular strip of cork, or tightly bound with twine. In order to ascertain whether a precipitate has been sufficiently or thoroughly washed, a few drops of the liquid, as it escapes from the funnel, may be collected from time to time on platinum foil, and subsequently slowly evaporated, whereby the presence of soluble, non-volatile bodies will be indicated by a visible resi- due. In some cases, and particularly where the bodies to be removed by washing are of a volatile nature, the completion of the operation may be most quickly determined by the application of chemical tests; thus, if the liquid in which the precipitate has been produced contains a sulphate or chloride, the complete removal of these salts will be indicated by testing a few drops of the filtered liquid with barium chloride or argentic nitrate, whilst if the liquid contain free acid, or a volatile alkali, such as ammonia, their complete displacement may be determined by means of litmus. Removing Precipitates from the Filter.—When a small quantity of a moist precipitate has to be taken from the filter for further examination, this is best done by carefully dipping the end of a thin glass rod into it, and subsequently detaching the adherent part of the precipitate upon a watch-glass, the interior of a small test-tube, or the microscopic glass slide. If a precipitate is to be removed from the filter as completely as possible, this maybe accomplished either by puncturing the point of the filter by means of a glass rod, and subsequently washing the precipitate with a fine stream of water or other liquid from a wash-bottle into a receptacle beneath, or the funnel may be held in a horizontal position, so that its rim projects inside the edge of OPERATIONS. 21 a porcelain dish or beaker, when by directing a fine stream of water against the sides of the filter by means of a wash-bottle, the pre- cipitate may be removed without breaking the filter. If, however, it is not desirable to add a liquid to the precipi- tate, the filter with its contents is first allowed to drain thoroughly in the funnel, and is then opened and placed upon a glass plate or upon several layers of bibulous paper, when the moisture will have soon become sufficiently absorbed to permit the ready removal of the precipitate with a glass rod or a spatula. When it is desired to dissolve a precipitate on the filter, the solvent should, when admissible, be first heated, and gradually poured upon the precipitate, and the filtrate, which will contain the pre- cipitate in solution, collected in a test-tube or beaker ; if the pre- cipitate does not thus become completely dissolved, the filtrate is again heated, and returned to the filter until complete solution is effected, which may be finally aided, if necessary, by the addition of a fresh portion of the solvent. If the precipitate should be considerable in amount, the larger portion may be first removed by means of a spatula, and transferred to a porcelain dish or beaker, and the residue upon the filter subsequently dissolved by the aid of the proper solvent. Drying Precipitates.—When a precipitate is required in a dry condition, it is first allowed to drain as completely as possible on the filter, and the funnel and filter are then placed in a hollow tin cone or cylinder (Fig. 6), which is supported on a piece of wire Fig. 6 Fig. 7. gauze over a moderate gas flame, being careful to so regulate the heat as not to char the filter. The operation may also be accom- plished still more quickly by opening the filter and spreading it with its contents upon a porcelain plate or watch-glass, which is placed upon a piece of wire gauze over a low flame, the proper precautions being observed to prevent excessive heat. In either 22 MANUAL OF CIIKMIC A L ANALYSIS. case, the precipitate may be first partially dried by opening the filter, and placing it with its contents upon several folds of bibu- lous paper. In the more exact requirements of analysis, the precipitate or other substance requiring desiccation may be placed under a bell- jar containing concentrated sulphuric acid or fragments of fused calcium chloride (Fig. 7), or in an air-bath or drying oven, pro- vided with a thermometer, and the temperature of which is Fig. 8. regulated by a gas flame (Fig. 8). By this means a uniform temperature may be readily maintained, which may be varied in accordance with special requirements. Weighing Precipitates Before ascertaining the weight of a pre- cipitate, it is usually required to be first completely dried at a defi- nite temperature. This is accomplished by means of the above illustrated air-bath. The precipitate, after partial drying upon the filter in the funnel, is placed upon a watch-glass, which, together with another glass of the same. size and a small brass clamp, has been previously accurately weighed. During the process of dry- ing the glasses are placed one within the other, so that the moisture from the precipitate contained on the uppermost glass may readily escape. When the precipitate has become sufficiently dry, it is removed from the air-bath, the lower watch-glass placed upon the upper, and the whole secured by means of the brass Fig. 9. OPERATIONS. 23 clamp (Fig. 9), in order that on cooling no moisture shall be ab- sorbed by exposure to the air. The glasses, with the inclosed precipitate, as indicated in the figure, are brought upon the balance, and the weight finally determined. In order to ascertain that no further loss takes place upon drying, the glasses are again opened, placed in the air-bath as before, and the operation re- peated until two successive weighings prove the weight to remain constant. Ignition.—The process of ignition refers to the subjection of solids to a more or less elevated temperature, and is employed for various purposes, but has, usually, for its object, the separa- tion of a volatile from a less volatile or non-volatile body, when the latter alone is required; it is also frequently employed for ascertaining the effect of strong heat upon a substance. In the latter case the substance is heated in a bent glass tube (Fig. 10), whereby the nature of the evolved gases or sublimate produced may be observed, whereas, if it be required simply to ascertain or confirm the volatile or non-volatile nature of a substance, it is heated on platinum foil, in the non-luminous flame. For the ignition of precipitates, however, the substance is placed in a porcelain or platinum1 crucible of convenient size (Fig. 11), sup- Fig. 10. Fig. 11. ported on a wire triangle, and heated in the nonduminous gas flame, or, if a higher temperature be required, by means of the blowpipe or gas blast-lamp. Determination of the Melting and Boiling Point.—The melting and boiling point of bodies under normal atmospheric pressure 1 The use of platinum vessels should be avoided for heating substances which develop chlorine, the alkaline hydrates, nitrates, and cyanides, metallic sul- phides, readily reducible metallic oxides, salts of the heavy metals with organic acids, or phosphates in the presence of organic compounds. 24 MANUAL OF CHEMICAL ANALYSIS. Fig. 12. being contant and unchangeable, the determination of these factors is an operation which is frequently resorted to for the purpose of establishing the iden- tity of a substance, and for affording confirmatory evidence of its purity. The melting point is determined by bringing a very small portion of the substance into the lower part of a capillary glass-tube (Fig. 12), and attaching the latter by means of a small rubber band to a thermometer, so that the substance will be on the same level and in the most direct possible contact with the thermometer bulb (Fig. 13). The ther- mometer, thus arranged, is then suspended, and the bulb and the capillary portion of the tube allowed to Fig. IB. Fig. 14. dip below the surface of water or sulphuric acid, contained in a beaker; the liquid employed being adapted to the melting point OPERATIONS. 25 of the substance. The liquid is then very gradually heated by means of a carefully regulated gas flame (Fig. 14), and the moment when the body melts in the capillary tube is accurately observed and the temperature noted. The boiling point is determined by bringing the liquid into a vessel adapted for fractional distillation (Fig. 15), or into an ordi- nary glass .flask provided with a doubly perforated cork (Fig. 16), Fig. 15. Fig. 16. in one orifice of which the thermometer is inserted, while the other is provided with a bent glass tube, which may be connected with a condenser. The therjnometer should not be allowed to become immersed in the liquid, but should simply project so far into the interior of the flask as to be surrounded by the vapor of the boiling liquid. On the appli- cation of heat, the boiling point will be indicated by the height of the mercurial column when the liquid is in a state of active ebulli- tion. Bending of G-lass Tubing.—Glass tubing may be regularly and uni- formly bent in any desired shape Fig. 17. 26 MANUAL OF CHEMICAL ANALYSIS. by the use of the upper edge of the common fish-tail gas-flame; the flame of the Bunsen gas-lamp cannot be well employed, producing unsatisfactory curves. The tube is held in a horizontal position in the flame at the point requiring to be bent, so that it becomes entirely enveloped by the illuminating portion ; it soon becomes covered with a deposit of soot, and, when sufficiently heated, bends itself by the weight of the unsupported end (Fig. 17). The bend, if properly made, will form a symmetrical curve, without diminish- ing the calibre of the tube at any point, and will be free from sharp angles. Glass tubing or rods when employed in analytical or chemical operations should have no sharp or protruding edges, but should be made smooth and round by holding the ends for a few seconds in the non-luminous gas-flame. REAGENTS. The methods of chemical analysis and investigation consist in bringing the substances under examination into contact with other bodies of known properties, and observing the resulting phenomena. These phenomena consist in alterations, either in state of aggregation, form, or color, resulting from some chemical change. All bodies which are employed for this purpose are called reagents, and the ensuing phenomena reactions. It is obvious, therefore, that a sufficient knowledge of theo- retical chemistry in its details, and especially a familiarity with the deportment, properties, and relations of the common com- pounds and reagents, are indispensable to the pursuit of chemical tests and examinations. Upon such knowledge depend the con- ception and comprehension of the conditions necessary for the formation of new compounds, and for the manifestation of the various reactions, as well as the correct inference from the obser- vations and results of all investigations; and without it they will remain unavailing and uncertain. No special and definite rules can. be assigned for the applica- tion of reagents in each instance, with respect to their proportion and quantity. These must depend upon the quantity and nature of the substance under examination and its solution, as well as upon the nature of the reagent, the strength of its solution, and the processes taking place in each particular reaction. Knowl- edge and reflection, as well as a ready comprehension of the object and aim of each test, of its issues, and of the possible inci- dents, and a correct inference from all phenomena, must decide at large, as well as in detail, not only what reagents should be employed, but also the amount and the conditions in each par- ticular instance. The general method for ascertaining the sufficient or slightly REAGENTS. excessive amount of a reagent, as has to be done before proceeding in the systematic course of analysis, is to add a few drops more of the reagent to the clear liquid obtained either by allowing the precipitate to subside, or by filtering off a small quantity of it; if any further precipitate is formed, the filtered portion must be re- turned, more of the reagent added, and the clear liquid again examined with a few additional drops of the reagent, until no further precipitate is produced. With some reagents, as, for in- stance, with hydrogen sulphide or ammonia water, this method of procedure is rendered unnecessary, an excess being indicated by their characteristic odor. A common error, and an obstacle to the less skilled, is the use of an undue excess of reagents. There are reagents which in many cases admit a free application without disadvantage to the correctness of the result—as, for instance, hydrogen sulphide, solution of calcium hydrate, etc. ; but the majority of reagents need to be applied in common tests only by a few drops of their solutions—as, for instance, baric, ferric, cupric, and argentic solu- tions, etc. On the other hand, there are not unfrequentty errors arising from an insufficient amount in the application of reagents, especially with dilute solutions, or in those cases in which the complete elimination of a substance by precipitation is required for the subsequent examination for other bodies: for instance, hydrogen sulphide, applied in a limited quantity, produces a white precipitate with solutions of mercuric salts; applied in excess, it gives a black precipitate. There are other instances where an excess of the solution under consideration, as well as of the reagent, may redissolve, and consequently destroy, the pre- cipitate whereon the reaction is based. In operations of chemical analysis it must always be borne in mind and well understood that, in the processes and phenomena taking place between the reagents and the substances act 'd upon, as in all chemical changes and reactions, certain laws and definite limits exist between cause and effect, and that the ability of cor- rectly applying knowledge, judgment, and skill, and of drawing the right inference from necessary as well as from casual reactions and phenomena, must rule and guide the methods and operations of the investigator, and carry them beyond mere conjecture and empiricism. It is beyond the scope of this work to describe the mode of preparing the reagents, their use and application, and their deport- ment with the common compounds, or to dwell upon the general rules of systematic methods, accuracy, order, neatness, and clean- liness to be observed in the execution of analytical work. For such information reference must be had to the text-books of applied and analytical chemistry. From a practical point of view, only the usual strength of the solution of the reagents, as best suited for the common tests and examinations, and the mode of 28 MANUAL OF CHEMICAL ANALYSIS. preparing a few of the rarer or special reagents, or of such as are not included among the medicinal chemicals considered in this volume, have been stated. As regards the strength of the solutions of reagents, unless otherwise stated, the test solutions described upon the following pages are invariably understood to be used wherever the name of the reagent only is stated. It hardly needs to be mentioned that all reagents must consist purely of their essential constituents, and must contain no admix- ture of any other substance; it must, therefore, be an invariable rule to test the purity of the reagents before they are employed. The reagents and their solutions must be preserved according to their nature; of those whose solutions are liable to alteration or decomposition only small quantities must be kept, and always in tightly closed glass-stoppered bottles. REAGENTS AND TEST SOLUTIONS. 29 REAGENTS AND TEST SOLUTIONS. Acetic Acid,—Spec. grav. 1.048. Acetic Acid, Diluted,—Obtained by mixing 1 part of acetic acid with 4 parts of water. Hydrochloric Acid.—Spec. gray. 1.16; containing 32.2 per cent, of absolute acid. Hydrochloric Acid, Diluted, — Spec. gray. 1.049; containing about 10 per cent, of absolute acid. Obtained by mixing 6 parts of hydrochloric acid with 13 parts of water. Hydrosulphuric Acid, See Hydrogen Sulphide. Nitric Acid.—Spec. grav. 1.42 ; con- taining 69.4 per cent, of absolute acid. When concentrated acids are applied in small tests only by the drop, as, for instance, in testing alkaloids, etc., they are taken from the bottle by dipping a glass rod into the acid and allowing the drop or drops to fall upon the substance to be acted upon, or better by means of a kind of pipette consisting of a thin, strong glass tube, adjusted at one end to a small caoutchouc bulb, and con- tracted at the other extremity to a capil- lary end. The fluid is drawn into the tube, and delivered again by gentle pressure of the bulb (Fig. 18). Nitric Acid, Diluted, — Spec. grav. 1.059; containing 10 per cent, of absolute acid. Obtained by mixing 1 part of nitric acid with 6 parts of water. Nitro-hydrochloric Acid (Aqua Regia).—4 parts by weight of nitric acid, spec. grav. 1.42, are gradually added to 15 parts by weight of hydrochloric acid, spec. grav. 1.160, in a capacious, open glass vessel, and, when effervescence has ceased, the product is transferred to glass-stoppered bottles, which should be not more than half filled, and preserved in a cool place. Oxalic Acid.—Solution of 1 part of crystallized oxalic acid in 10 parts of water. Picric Acid,—Saturated aqueous solution of picric acid. Fig. 18. 30 MANUAL OF CHEMICAL ANALYSIS. Sulphuric Acid, Concentrated,—Spec. grav. 1.84; containing 97 per cent, of absolute acid. Sulphuric Acid, Strong.—Spec. grav. 1.64; containing 72.75 per cent, of absolute acid. Obtained by carefully mixing, in a flask or beaker, 3 parts of concentrated acid with 1 part of water (Fig. 19). Fm. 19. In diluting concentrated sulphuric acid with water, the acid should invariably and gradually be added to the water, and in vessels which are either placed in cold water or which are not liable to crack from the heat evolved. Sulphuric Acid, Diluted.—Spec. grav. 1.068; containing about 10 per cent, of absolute acid. Obtained by mixing 1 part of con- centrated acid with 9 parts of water. Sulphurous Acid,—Spec. grav. 1.046. An aqueous solution of sulphurous acid gas, saturated at 15° C. (59° F.), containing 36 times its volume, or about 9.5 per cent, by weight of the gas. Tannic Acid.—Solution of 1 part of tannic acid in a mixture consisting of 18 parts of water and 2 parts of alcohol. Tartaric Acid.—Solution of 1 part of crystallized tartaric acid in 5 parts of water. Albumen,—The white of one egg is triturated with 100 cubic centimeters of water, and is then filtered through cotton previously moistened with water. Alcohol.—Spec. grav. 0.820 ; containing 91 per cent, by weight or 94 per cent, by volume of absolute alcohol. Alcohol, Absolute Spec. grav. 0.795. Alcohol, Amylic.—Spec. grav. 0.816 to 0.818. Aluminium,—Metallic aluminium in the form of wire or ribbon. Ammonia Water (Aqua Ammonias).—Spec. grav. 0.959. An aqueous solution of ammonia, containing 10 per cent, by weight of the gas. REAGENTS AND TEST SOLUTIONS. 31 Ammonia Water, Stronger (Aqua Ammonias Fortior, U. S. P.). —Spec. grav. 0.900. A nearly saturated aqueous solution of ammonia, containing 28 per cent, by weight of the gas. Ammonium Carbonate.—Solution of 1 part of uneffloresced am- monium carbonate in a mixture of 4 parts of water and 1 part of ammonia water. Ammonium Chloride.—Solution of 1 part of crystallized ammo- nium chloride in 10 parts of water. Ammonium Molybdate. Ammonium Molybdate in Nitric Acid. — Solution of 1 part of ammonium molybdate in 10 parts of water, to which 10 parts of nitric acid, spec. grav. 1.2, are subsequently added. Ammonium Oxalate.—Solution of 1 part of crystallized ammo- nium oxalate in 20 parts of water. Ammonium Phosphate.—Solution of 1 part of ammonium phos- phate in 15 parts of water. Ammonium Sulphide. — A solution of ammonium sulphide in water; it is obtained by saturating, at 15° C. (59° F.) or a lower temperature, 8 parts of Aqua Ammonise Fortior, U. S. P., with hydrogen sulphide gas, and bjr subsequent addition of 2 parts of ammonia water. It is best preserved in small vials, tightly corked, and in a cool place. This solution, being concentrated, has to be employed, in the common tests, only in small quantities, mostly by drops. When hydrogen sulphide is at hand, ammonium sulphide may, in many of its applications, be produced by saturating the liquid under examination with the gas, and by the subsequent addition of ammonia water; or, in.ammoniated solutions, if dilution does not interfere with the reaction, by the addition of an aqueous solu- tion of hydrogen sulphide. Aniline Sulphate.—Solution of 5 drops of aniline in 25 cubic centimeters of diluted sulphuric acid. Argentic Nitrate.—Solution of 1 part of crystallized argentic nitrate in 20 parts of water. Argentic Nitrate, Ammoniated.—Solution prepared by adding ammonia water, spec. grav. 0.959, in drops, to test-solution of argentic nitrate, until the precipitate at first formed is very nearly all redissolved, and filtering. Argentic Sulphate.—Solution of 1 part of argentic sulphate in 250 parts of water. Auric Chloride.—Solution of 1 part of auric chloride in 20 parts of water. Barium Chloride. — Solution of 1 part of crystallized barium chloride in 10 parts of water. Barium Hydrate (Baryta-water).—Saturated aqueous solution of barium hydrate, containing about 5 per cent, of the hydrate. Barium Nitrate. — Solution of 1 part of crystallized barium nitrate in 20 parts of water. 32 MANUAL OF CHEMICAL ANALYSIS. Benzin (Petroleum Benzin or Petroleum Ether).—Spec. gray, from 0.670 to 0.675, and boiling at 50 to 60° C. (122 to 140° F.). Benzol.—Spec. grav. 0.885. Borax. Bromine Water.—A saturated solution of bromine in water. Calcium Chloride.—Solution of 1 part of pure crystallized cal- cium chloride in 10 parts of water. Calcium Hydrate (Lime-water).—Saturated aqueous solution of calcium hydrate. Calcium Sulphate.—Saturated aqueous solution of calcium sul- phate, containing about 0.2 per cent, of the salt. Carbon Bisulphide.—Spec. grav. 1.272. Chlorine Water.—A saturated aqueous solution of chlorine, con- taining about 0.4 per cent, by weight of the gas. For analytical use, this solution is best preserved in small vials, tightly corked and sealed, in a cool place, and protected from the light. Chloroform.—-"Spec. grav. 1.480. Cobaltous Nitrate.—Solution of 1 part of cobaltous nitrate in 10 parts of water. Copper.—Metallic copper in slender wire, or thin foil cut into strips. Cupric Sulphate.—Solution of 1 part of crystallized cupric sul- phate in 10 parts of water. Cupric Sulphate, Ammoniated. — Solution prepared by adding ammonia water, spec. grav. 0.959, in drops, to test-solution of cupric sulphate, until the precipitate at first formed is very nearly all re- dissolved, and filtering. Cupric Tartrate, Alkaline Solution of, (Fehling’s Solution).— 17.32 grams (267.3 grains) of pure crystallized cupric sulphate are dissolved in 100 cubic centimeters (about 3 fluidounces) of water; and 85 grams (2 ounces and 457 grains) of pure crystallized potas- sium and sodium tartrate are dissolved in 300 cubic centimeters (about 10 fluidounces) of a 10 per cent, solution of sodium hydrate. The cupric solution is then gradually added to the alkaline solu- tion, and, having been well mixed, so much water is added as to make the whole measure 500 cubic centimeters (16 fluidounces). The solution should be free from yellowish-brown sediment, and • should deposit none upon boiling. Ether.—Spec. grav. 0.750. Ferric Chloride.—Solution of 1 part of ferric chloride in 10 parts water. Ferric Dinitrosulphide.—Obtained by adding, drop by drop, a solution of ferric chloride or sulphate, with constant stirring, to a mixture consisting of equal parts of strong solutions of potassium nitrate and ammonium sulphide, heating the liquid to boiling for a few minutes, and filtering while hot from the sulphur. The deep-colored liquid deposits, on cooling, black, needle-shaped rhombic prisms of ferric dinitrosulphide; these are dissolved 1 part in 10 parts of water, to give the required solution. REAGENTS AND TEST SOLUTIONS. 33 Ferrous Sulphate.—Solution of 1 part of ferrous sulphate, ob- tained by precipitation with alcohol, in 10 parts of water. Ferrous sulphate is best obtained by pouring an aqueous solu- tion of freshly prepared crystallized ferrous sulphate, saturated at the boiling-point, into strong alcohol, collecting the precipitate upon a filter, washing with a little alcohol, drying by pressing between filtering-paper, and by immediately filling the humid salt into small warm vials, which are corked and sealed while warm. The absence of ferric sulphate may be ascertained by testing the solution with potassium ferroeyanide; no blue turbidity, or only a very slight one, should occur. Gelatin. —Solution obtained by digesting 1 part of isinglass (ichthyocolla) with 50 parts of water, on a water-bath, for half an hour, and subsequently filtering through cotton, moistened with water. Gold.—Metallic gold in the form of leaf. Hydrogen, Nascent, is a very delicate means of detecting arsenic. The test depends upon the production of hydrogen arsenide (ar- seniuretted hydrogen), whenever arsenic is present in any soluble form, in which hydrogen is being evolved by the action of dilute sulphuric or hydrochloric acid upon zinc or magnesium. From the hydrogen arsenide the arsenic can be separated in a charac- teristic and unmistakable form, either as metal, or by leading the gas into a solution of an easily reducible metallic salt, as, for instance, argentic nitrate, in which case the silver is precipitated and a solution of arsenious acid is obtained. AsIIj + 3FI20 4- 6AgN03 = H3As03 4- 6HN03 -f 3Ag2. Marsh’s Test.—Of the different methods for the application of this test, the one long and commonly known as Marshs test is pre-eminently adapted for the recognition, as also for the quanti- tative estimation of small amounts of arsenic. A complete and simple form of apparatus for the application of Marsh’s test is represented in Fig. 20. It consists of a gas generating flask or Woulff’s bottle (A), of about 300 to 400 cubic centimeters (10 to 14 ounces) capacity, provided by means of a peforated cork or rubber stopper with a funnel tube (6), and a drying tube (a), loosely stopped at each end with a small plug of cotton, and par- tially filled with dry calcium chloride in small fragments, followed by a layer of small pieces of dry potassium hydrate; the latter serving to retain any acid which may accidentally be carried over with the gas, as also any trace of hydrogen sulphide. The end of this tube is connected with a reduction tube (d), of hard German glass, narrowly drawn out in one or more places, and at the end into a capillary point, and bent up so as to form a vertical jet, as shown in Fig. 20. The test consists in introducing into the flask (A) pure granu- lated zinc or magnesium, and adding gradually, by means of the funnel tube, a cold mixture of one part of sulphuric acid and 3 34 MANUAL OF CHEMICAL ANALYSIS. three parts of water, when the hydrogen is more or less quickly evolved. When perfectly pure zinc is employed, the development Fig. 20. of gas takes place very slowly, and may be hastened by the addi- tion of a few drops of test solution of platinic chloride. Fig. 31. It is of primary importance in each case where the test is ap- plied to first ascertain the absolute purity of the zinc or magne- sium and acid employed. REAGENTS AND TEST SOLUTIONS. 35 After the evolution of gas has continued long enough to expel the atmospheric air,1 the reduction tube (cl) is heated to redness in the part indicated in the figure for about ten minutes, the escaping gas is lighted, and a piece of white porcelain is held in the flame. If no dark deposit takes place, either in the tube or on the porcelain, the reagents may be considered pure, and the liquid to be tested may then be added through the funnel tube (b), first in small amounts, and the operation continued in the manner described. If arsenic-spots or mirrors are obtained in the tube, a number of them may be produced by heating the tube in at least two places, at distances of about three inches, or if an approximately quantitative estimation of the arsenic is desired, all the arsenic may be obtained by the employment of a larger reduction tube and several flames (Fig. 21). The obtained arsenic mirrors may be examined for identification, or quantitatively determined by subsequently removing the tube and determining the increase in weight. In cases where it is desirable to estimate the entire amount of arsenic, and guard against possible loss, instead of allowing the developed gas to burn, it is preferable to conduct it into a solu- tion of argentic nitrate, in which case any arsenic which may have escaped reduction in the glass tube will be recovered, and contained in the solution as arsenious acid, together with the ex- cess of the undecomposed silver salt. As is well known, certain compounds of antimony, when brought into Marsh’s apparatus, give rise to the formation of hydrogen antimonide (antimoniuretted hydrogen), analogous in composition to hydrogen arsenide, which, when subjected to the same process of reduction as above described, produces black spots of metallic antimony. These spots are so different in their physical appear- ance and properties as to be readily distinguished by the experi- enced operator, and, when subjected to chemical tests, display so marked a difference that their discrimination from those of arsenic is readily effected. To enumerate in detail all the special tests for each of these two metals would lead beyond the scope of this work ; the prin- cipal distinctive characters, however, will be briefly described. The mirror of arsenic, as obtained in the reduction-tube, when gently heated during the simultaneous development of a current of hydrogen, can easily be driven from one place to another, and, if the gas be allowed to escape at the exit tube, the develop- ment of the arsenical or garlic-like odor can at the same time be observed; whilst antimony, on account of the much higher temperature required for its volatilization, cannot be so readily 1 This maybe determined by holding an inverted dry test-tube over the point of exit of the gas for a few seconds, and then bringing the mouth of the test- tube in contact with the flame ; if the air be entirely expelled from the appa- ratus, the gas burns quietly, if not, a slight explosion ensues. 36 MANUAL OF CHEMICAL ANALYSTS. removed from the place in which it was deposited, and the escaping gas is quite odorless. The spots of arsenic, obtained by holding the cold surface of a piece of white porcelain in the flame during the development of the hydrogen arsenide, have a bright metallic lustre, whilst the spots of antimony have a dull velvety black appearance. When touched with a solution of sodium hypochlorite or chlorinated lime, the arsenic spots become immediately dissolved, whereas the spots of antimony remain unaffected ; by this means arsenic can be detected, even when accompanied by antimony. The spots of arsenic, when touched with a drop of a solution of ammonium sulphide, and gently warmed, become completely dis- solved, and, on being allowed to dry, display the bright yellow color of arsenious sulphide; antimony under the same circum- stances gives an orange-red coloration of antimonious sulphide. The yellow arsenious sulphide remains unaffected upon the addi- tion of a drop of hydrochloric acid, whilst antimonious sulphide is readily dissolved; and inversely a solution of ammonium carbonate dissolves the arsenious sulphide, but does not act upon the anti- monious sulphide. These few points of distinction in relation to this important and characteristic test are sufficient in the majority of cases to render possible a prompt determination, as to the pre- sence or absence of one or both of these metals, and to effect their discrimination. Precautions to be observed in the Application of Marsh's Test for Arsenic.—Although this test is so delicate as to render possible the detection of exceedingly small amounts of arsenic, certain precautions are necessary, which, if not observed, may prove a source of serious error, and lead to incorrect inferences. The sulphuric acid employed for generating the hydrogen gas should be free from the lower oxy-acids of sulphur and selenium, of the proper dilution, and cold; for if concentrated and warm, sulphurous-acid gas will be produced, which, combining with the nascent hydrogen, forms hydrogen sulphide, and a precipitation of arsenic as insoluble sulphide would result. Nitric acid and nitrates, free chlorine and other similar oxidiz- ing agents must be rigidly excluded in the application of the- test, as preventing the formation of the gaseous hydrogen arsenide. Hydrochloric acid can also not be substituted to advantage for the sulphuric acid for the generation of the hydrogen, for although it does not interfere with the formation of hydrogen arsenide, yet on account of its greater volatility, and tendency to the produc tion of the so called zinc spots, the presence, of arsenic might be erroneously inferred. Another test which may be employed for the detection of small amounts of arsenic, and which commends itself for con- venience of application, is that known as: Fleitm.ann's Test.—This consists in the generation of hydro- gen by the action of a strong solution of potassium or sodium REAGENTS AND TEST SOLUTIONS. 37 hydrate on metallic zinc or aluminium, by the aid of heat. The operation may be performed quickly in a long test-tube, taking care that the tube is only filled to about one-tenth of its capacity. As soon as the gas is generated, the solution to be tested is cautiously added to the alkaline liquid, and a cap of white filter- ing paper, moistened with a drop of solution of ar- gentic nitrate, placed over the tube (Fig. 22). If arsenic is present, a purplish-black spot, due to the reduction of the argentic nitrate to metallic silver, will be produced upon the moist paper cover. This reaction is of particular importance and value, for while antimony combines with hydrogen evolved from dilute acids and zinc, it does not combine with hydro- gen evolved by the action of an alkali on the same metal. Hydrogen Sulphide (Hydrosulphuric Acid, or Sul- phuretted Hydrogen).—Obtained by the action of di- luted sulphuric or hydrochloric acids upon ferrous sul- phide. Among the several convenient forms of ap- paratus for the continuous preparation of the gas and to keep it ready for use, the one represented in Fig. 23 is frequently employed. It consists of three glass bulbs, the two lower ones being a single piece, and the upper one, prolonged by a tube reaching to the bottom of the lower, being ground air-tight into the neck of the second. Through the tubulure of the middle bulb the ferrous sulphide is introduced, and the tubulure then closed by a cork containing a wide glass tube provided with a stop- cock, or with a rubber tube, closed bv a Mohr’s wire clamp (see p. 74). The acid is poured in through the safety-tube, runs into the bottom globe, and rises to overflow the ferrous sulphide in the middle one. When the air has been allowed to escape through the delivery-tube, and this is closed, the pressure of the accumulating hydrogen sul- phide forces the liquid from the second bulb down into the lower, and thence into the upper bulb, thus stopping the action, and pre- serving a volume of the gas ready for use. Another form of apparatus, which is recommended for sim- Fig. 22 Fig. 23. 38 MANUAL OF CHEMICAL ANALYSIS. plieity of construction and the facility with which it may be cleansed or supplied with fresh material, is represented in Fig. 24. A glass cylinder, about 40 centimeters (nearly 16 inches) high, and 12 centimeters (4f inches) wide, is partially filled with diluted sulphuric acid. It is closed with a cork or rubber stopper having a lateral notch, and carrying a rather long tube, drawn out at its lower end to a small point. This tube is filled with coarse frag- ments of ferrous sulphide, and is closed with a tightly fitting cork or rubber stopper, through which the delivery-tube (provided with a stop-cock) passes. When the apparatus is not in use, the inner cylinder is drawn upwards, until its point merely is immersed in the liquid. When the gas is required, the tube is depressed to the position shown in the figure, and the stop cock opened. The acid then enters from below, and generates a more or less rapid current of the gas, which may be regulated by means of the stop-cock. When the latter is closed, the pres- sure of gas inside the inner tube forces the liquid back into the glass cylinder. When the above described forms of appa- ratus are not at hand, hydrogen sulphide may be generated, in small tests, from a little flask or test-tube (Fig. 25), taking care that none of the contents of the flask pass through the de- livery-tube into the liquid under examination. Fig. 24. Fig. 25. Hydrogen Sulphide Water.—A solution of hydrogen sulphide (hy- drosulphuric acid, or sulphuretted hydrogen) in water, saturated at 15° C. (59° F.), or at a lower temperature, containing about four times its volume of the gas. The gas is obtained, as above described, by the action of diluted sulphuric acid upon ferrous sulphide, and is washed by water, contained in a small flask or cylinder (Fig. 2b), before passing it into water for absorption. In order to preserve the hydrogen sulphide in this form, it is advisable to fill the freshly-prepared saturated solution immedi- ately into small vials, and to place them, tightly corked, in an inverted position, in a cool place. When, in the course of a test, a solution lias to be acted upon REAGENTS AND TEST SOLUTIONS. 39 for some time by hydrogen sulphide, a test-tube or flask may be employed, of such size as nearly to be filled by the liquid. It may then be tightly stoppered, allowing sufficient escape of air before corking, if it has to be warmed. Fig. 26. Indigo Solution (Solution of Indigo in Sulphuric Acid).—1 part of finely powdered indigo is gradually added to 6 parts of fuming sulphuric acid; the mixture, after having been well stirred, is then allowed to repose in a covered vessel for about two days, when it is poured into 20 times its volume of water, the solution well mixed, filtered, and preserved for use in a glass-stoppered bottle. Iodine Water.—A saturated solution of iodine in water. Iodinized Potassium Iodide.—Solution of 1 part of iodine and 8 parts of potassium iodide in 60 parts of water. Magnesium.—Metallic magnesium in the form of wire or ribbon. Magnesium Mixture (Ammoniated Magnesium Sulphate).—A solution of 11 parts of crystallized magnesium chloride or sul- phate and 14 parts of ammonium chloride in 70 parts of stronger ammonia water and 130 parts of water. (Magnesium chloride is to be preferred to the sulphate in the preparation of the solution, as having less tendency in its application to produce basic salts.) Magnesium Sulphate.—Solution of 1 part of crystallized mag- nesium sulphate in 10 parts of water. Mercuric Chloride.—Solution of 1 part of crystallized mercuric chloride in 20 parts of water. Mercuric Oxychloride (.Bohlic/s Reagent).—To a dilute solution of mercuric chloride in water (1 : 30) a dilute solution of potas- sium carbonate (1 : 50) is added, drop by drop, with constant agitation, until a perfectly neutral solution is obtained. Phosphorous Salt (Sodium-ammonium-hydrogen Phosphate). 40 MANUAL OF CHEMICAL ANALYSIS. Platinic Chloride.—Solution of 1 part of platinic chloride in 20 parts of water. Plumbic Acetate.—Solution of 1 part of crystallized plumbic acetate in 10 parts of water. Plumbic Nitrate. — Solution of 1 part of crystallized plumbic nitrate in 10 parts of water. Potassium Acetate.—Solution of 1 part of potassium acetate in 5 parts of water. Potassium Antimoniate.—A cold, saturated, aqueous solution of potassium antimoniate. Potassium Bicarbonate.—Solution of 1 part of potassium bicar- bonate in 10 parts of water. Potassium Bichromate.—Solution of 1 part of potassium bichro- mate in 10 parts of water. Potassium Carbonate.—Solution of 1 part of pure potassium carbonate in 3 parts of water. Potassium Chromate, Neutral.—Solution of 1 part of potassium chromate in 10 parts of water. Potassium Cyanide. Potassium Ferricyanide.—Solution of 1 part of potassium ferri- cyanide in 10 parts of water. To be prepared as required. Potassium Ferrocyanide.—Solution of 1 part of potassium ferro- cyanide in 10 parts of water. Potassium Hydrate (Liquor Potassee, U. S. P.).—Containing 5 per cent, of potassium hydrate. Potassium Iodide.—Solution of 1 part of potassium iodide in 20 parts of water. Commercial potassium iodide occasionally contains traces of potassium iodate, and this should be eliminated by dissolving the salt in boiling alcohol, to saturation, filtering the hot solution, and, when cool, collecting and drying the separated salt. Potassium Mercuric Iodide.—A solution of 1.35 grams of mer- curic chloride and 4.98 grams of potassium iodide in 100 cubic centimeters of water. Potassium Mercuric Iodide with Potassium Hydrate (Nessler's Test).—10 grams of potassium iodide are dissolved in 10 grams of hot water, and a hot solution of 5 grams of mercuric chloride added until the precipitate of mercuric iodide ceases to be dis- solved. The mixture is then filtered, the filtrate mixed with a concentrated solution of 30 grams of potassium hydrate, and diluted to the measure of 200 cubic centimeters. To this solu- tion 5 cubic centimeters of the above-prepared mercuric chloride solution are subsequently added, and the liquid, after having been allowed to become perfectly clear by standing, preserved in well stoppered bottles. Potassium Nitrate. Potassium Nitrite. Potassium Permanganate.—Solution of 1 part of potassium per- manganate in 1000 parts of water. REAGENTS AND TEST SOLUTIONS. 41 Potassium Sulphate.—Solution of 1 part of potassium sulphate in 15 parts of water. Potassium Sulphocyanide.—Solution of 1 part of potassium sul- phocyanide in 20 parts of water. Soda-Lime.— Quicklime is slaked with a solution of sodium hydrate, of such a strength that about 2 parts of quicklime are mixed with 1 of sodium hydrate; the product, after drying, is heated to bright redness, subsequently finely powdered, and pre- served in tightly stoppered bottles. Sodium Acetate. — Solution of 1 part of crystallized sodium acetate in 5 parts of water. Sodium Bicarbonate. — Saturated aqueous solution of sodium bicarbonate. Sodium Bitartrate. — Saturated aqueous solution of sodium bitartrate. Sodium Carbonate.—Dehydrated by exsiccation. Sodium Carbonate.—Solution of 1 part of crystallized sodium carbonate in 10 parts of water. Sodium Hydrate (Liquor Sodm, U. S. P.).—Containing 5 per cent, of sodium hydrate. Sodium Hyposulphite.—Solution of 1 part of crystallized sodium hyposulphite in 10 parts of water. " Sodium Molybdate. Sodium Phosphate.—Solution of 1 part of crystallized sodium phosphate in 10 parts of water. Stannous Chloride.—Saturated solution of real and pure tinfoil in concentrated hydrochloric acid, with subsequent addition of a little concentrated hydrochloric acid. Starch Mucilage (Gelatinized Starch).—1 part of finely powdered starch is triturated with a little water, the mixture diluted with about 100 parts of water, and subsequently heated to the boiling- point; after cooling, and having been allowed to subside, the clear liquid is decanted. The reagent should be freshly prepared, when required. Zinc.—Metallic zinc in slender sticks, or small fragments, or in thin disks, prepared by melting and pouring in a thin stream into water. Neutral Litmus Solution is prepared by digesting 1 part of com- mercial litmus with alcohol, with the aid of a gentle heat, for about fifteen minutes; the alcoholic liquid, which contains objec- tionable coloring matters, is decanted, and the litmus subsequently extracted with about 10 parts of water, by digestion on the water- bath, and filtered. The filtrate thus obtained is divided into two equal parts; to one of them, by means of a glass rod, very dilute sulphuric acid is added, with constant stirring, until the liquid turns faintly red; PREPARATION OF TEST PAPERS, ETC 42 MANUAL OP CHEMICAL ANALYSIS. the red liquid is then added to the reserved blue portion, and the whole well mixed. If it is desirable to preserve the solution for any length of time, about 5 per cent, of alcohol should be added, or it must be kept in bottles provided with a perforated stopper, through which a bent glass tube may be inserted, or loosely stopped with cotton, in order to admit access of air, and exclude dust; if these precau- tions be neglected, the solution soon becomes mouldy or dis- colored, and unfit for use. Blue Litmus-Paper is prepared by drawing unsized white paper (Swedish filtering-paper) through the above neutral liquid. Red Litmus-Paper is prepared by drawing unsized white paper (Swedish filtering-paper) through the acidulated reddened part of the litmus solution, as obtained and described above, in the prepa- ration of neutral litmus solution. The paper thus prepared is dried in warm air by suspension over a thread, and for ready use is cut into strips about one-third of an inch wide and four inches long, and preserved inclosed in paraffin-paper, or in tightly corked bottles, protected from the light. In reactions of neutralization, where carbonic aid gas is evolved, this substance acts on litmus, and may impair the cor- rectness of the test; in such operations it is therefore better, if admissible, to operate on warm solutions, in order quickly to expel the carbonic acid gas; if heat be incompatible, turmeric- paper may be used instead of litmus-paper. Turmeric Solution.—Obtained by digestion of 1 part of powdered turmeric in a mixture of 4 parts of alcohol and 3 parts of water. After one or two days, the liquid is filtered off and preserved. Turmeric-Paper is prepared from this tincture by steeping in it white unsized paper (Swedish filtering-paper). The paper need not be preserved from the action of the atmosphere, since it remains unchanged by carbonic acid. Alkanet-Paper is prepared like litmus-paper, by saturating un- sized paper with a solution of the alkanet-red. This is obtained by extracting dry alkanet root with ether; the filtered solution is ready for use. The blue paper may be obtained from the red one by dipping ' it into an aqueous solution of sodium carbonate (1:500). A neu- tral paper, answering for the alkaline as well as the acid test, may be prepared by dividing the ethereal solution of alkanet-red into two equal parts; to one is added, drop by drop, an aqueous solu- tion of sodium carbonate, until the red is just changed to a dis- tinct blue tint; then both liquids are mixed and used for the preparation of the paper. Plumbic Acetate-Paper serves for the detection of hydrogen sul- phide, and is prepared by dipping white unsized paper (Swedish filtering-paper) into a solution of plumbic acetate, and, when dry, cutting into strips of a convenient size, which may be preserved inclosed in paraffin-paper. A SYSTEMATIC COURSE OP QUALITATIVE CHEMICAL ANALYSIS. Chemical tests and examinations must be founded upon a thorough knowledge of the nature and relations of the reagents, and of their deportment with the common compounds, and also upon a certain fixed order and methodical system in their appli- cation. These attainments, and the necessary skill, experience, and judgment, are requisite for every one who enters upon testing and investigation with a chance or claim of accuracy or certainty. It is advisable in analytical work to enter the result of each test as soon as satisfactorily completed into a note-book, whereby the brief symbolic notation may be used to advantage; the analysis is thus recorded, step by step, as it progresses until com- pleted. It may also be stated here that a reasonable economy with the substance under examination, especially if only of a small quan- tity, and with its solutions is necessary, so as to leave enough of the former for unseen contingencies and for confirmatory tests, as well as to repeat or verify any and all results of the examina- tion. All tests and reactions are, therefore, performed on as small a scale as is reasonable and appropriate in the particular case; and all operations should proceed accordingly, and with constant observance of the principles and processes whereon they depend. The following brief outline of a simple progressive course ot qualitative chemical analysis depends, first, upon the successive elimination of groups of elementary compounds which possess certain common chemical properties, and, finally, upon the recog- nition of each member of such groups; it may therefore serve as a guide whenever, in the course of investigation, recourse is to be had to such a systematic method of analysis. When the object of the examination is only to establish the presence or absence of some particular substance, the character- istic reagent may be employed at once, provided there be no other substance present which would interfere with, or exclude, the direct application of the test; but, if a qualitative analysis is required, the substance, if a solid body, may be subjected first to 44 MANUAL OF CHEMICAL ANALYSIS a preliminary examination in the dry way, by which means approximate information as to its composition may be obtained; after this, it is dissolved and examined. The course of qualitative analysis, therefore, consists of three parts I. Preliminary examination in the dry way. II. Solution, or conversion into the liquid form. III. Analysis of the solution. I. PRELIMINARY EXAMINATION. This consists in an accurate observation, often by the aid of a lens or a microscope, of the physical properties of the substance, its form, color, hardness, gravity, and odor, and of its deportment at a high temperature, either alone, or in contact with some chemical compound which produces decomposition. 1. The substance is heated in a dry narrow tube open AT BOTH ENDS (Fig. 27). (a) The substance remains unaltered; indicating absence of organic matter, of salts containing water of crystallization, and of volatile com- pounds. (Id) Non-volatile organic substances car- bonize and blacken, evolving empyreu- matic, inflammable gases. (c) The substance fuses, expelling aqueous vapors, which condense in the cooler parts of the tube ; indicating salts with water of crystallization (these will generally re- solidify after the expulsion of the water), or decomposable hydrates, which often give off their water without fusing. The acid or alkaline reaction of the condensed vapors should be determined by means of litmus-paper. (fi) A change of color takes place ; zinc oxide assumes a yellow color while hot, which disappears again on cooling ; mer- curic oxide shows a transitory brown coloration, followed by the sublimation of metallic mercury; mercuric iodide sublimes with a yellow color; chromates, and the oxides of lead and bismuth are colored brown. () (c) per cent. 14 per cent. 8 per cent. 18 6 (3) (1) Difference Accordingly 1 part of the 32 per cent, acid is to be mixed with 3 parts of the 8 per cent, acid, or 100 grams Hydrochloric Acid = 82 grams HC1 300 grams “ “ = 24 “ “ 400 grams Hydrochloric Acid = 56 grams HC1 100 grams “ “ = 14 grams “ or Table of the quantity by weight of Hydrochloric Acid Gas, and the cor- responding equivalent of Chlorine, contained in 100 parts by weight of Aqueous Hydrochloric Acid of different specific gravities ( Ore). Temperature 15° C. (59° F.). Specific gravity. Per ct. of hydrochl. acid. Per cent, of chlorine. Specific gravity. Per ct. of hydrochl. acid. Per cent, of chlorine. Specific gravity. Per ct. of hydrochl. acid. Per cent, of chlorine 1.2000 40.777 39.675 1.1328 26.913 26.186 1.0637 13.049 12.697 1.1982 40.369 39.278 1.1308 26.545 25.789 1.0617 12.641 12.300 1.1964 39.961 38.882 1.1287 26.098 25.392 1.0597 12.233 11.903 1.1946 39.554 38.485 1.1267 25.690 24.996 1.0577 11.825 11.506 1.1928 39.146 38.089 1.1247 25.282 24.599 1.0557 11.418 11.109 1.1910 38 728 37.692 1.1227 24.874 24.202 1.0537 11.010 10.712 1.1893 38.330 37.269 1.1206 24.466 23.805 1.0517 10.602 10.316 1.1875 37.923 36.900 1.1185 24.058 23.408 1.0497 10.194 9.919 1.1857 37.516 36.503 1.1164 23.650 22.012 1.0477 9.786 9.522 1.1846 37.108 36.107 1.1143 23.242 22.615 1.0457 9.379 9.126 1 1822 36.700 35.707 1.1123 22.834 22.218 1.0437 8.971 8.729 1.1802 36.292 35 310 1.1102 22.426 21.822 1.0417 8.563 8.332 1.1782 35.884 34.913 1.1082 22.019 21.425 1.0397 8.155 7.935 1.1762 35.476 34.517 1.1061 21.611 21.028 1.0377 7.747 7.538 1.1741 35.068 34.121 1.1041 21.204 20.632 1.0357 7.340 7.141 1.1721 34.660 33.724 1 1020 20.796 20.235 1.0337 6 932 6.745 1.1701 34.252 33.328 1.1000 20.388 19.837 1.0318 6.524 6.348 1.1681 33.845 32.931 1.0980 19.980 19.440 1.0298 6.116 5.951 1.1661 33.437 32.535 ! 1.0960 19.572 19.044 1.0279 5.709 5.554 1.1641 33.029 32.136 1.0939 19.165 18.647 1.0259 5.301 5.158 1.1620 32.621 31.745 1.0919 18.757 18.250 1.0239 4.894 4.762 1.1599 32.213 31.343 1.0899 18.349 17.854 1.0220 4.486 4.365 1.1578 31.805 30.946 1.0879 17.941 17.457 1.0200 4.078 3.968 1.1557 31.398 30.550 1.0859 17.534 17.060 1.0180 3.670 3.571 1.1537 30.990 30.153 i 1.0828 17.126 16.660 ! 1.0160 3.262 3.174 1.1515 30.582 29.757 1.0818 16 718 16.267 1.0140 2.854 2.778 1.1494 30.174 29.361 1.0708 16.310 15.870 1.0120 2.447 2.381 1.1473 29.767 28.964 1.0778 15.902 15.474 1.0100 2.039 1.984 1.1452 29.359 28.567 1.0758 15.494 15.077 1.0080 1.631 1.588 1.1431 28.951 28.171 1.0738 15.087 14.580 1.0060 1.124 1.191 1.1410 28.544 27.772 | 1.0718 14.679 14.284 1.0040 0.816 0.795 1.1389 28.136 27.376 1.0697 14.271 13.887 1.0020 0.408 0.397 1.1369 27.728 26.979 1.0677 13.863 13.490 1.1349 27.321 26.583 1.0657 13.457 13.094 ACID A 159 The specific gravity of the aqueous acid being decreased by an increase of temperature, and increased by a decrease of temperature, the consequent change of the specific gravity amounts for each degree of the centigrade thermometer in either direction— For acids of a specific gravity of 1.1741 to those of 1.1389 to about 0.0005 “ “ “ 1.1349 “ 1.0980 “ 0.0004 “ “ “ 1.0939 “ 1.0637 “ 0.0003 For instance: An acid of a specific gravity of 1.1234 at 16° C., containing 25 per cent, of hydrochloric-acid gas, will have at 18.5° C. a specific gravity of 1.1234 — (0.0004 X 2.5) = 1.1224, and at 13.5° C. a specific gravity of 1.1234 + (0.0004 x2.5) = 1.1244. ACIDUM HYDROCYANICUM DILUTUM, ACIDUM HYDROCYANATUM. Diluted Hydrocyanic Acid. Prussic Acid. Ger. Cyanwasserstoffsaure, Blausaure ; Fr. Acide hydrocyanique ; Sp. Acido hidrocianico. Pure hydrocyanic acid is a thin, colorless, and exceedingly poi- sonous, volatile, and unstable liquid. Its odor is very powerful and characteristic, resembling that of peach-blossoms or oil of bitter almonds. It mixes with water, alcohol, and ether, in all propor- tions. The officinal acid is a very dilute hydro-alcoholic solution, containing two per cent, of absolute acid. It imparts a faint eva- nescent color to litmus, and forms a white curdy precipitate with a solution of argentic nitrate. This precipitate is soluble in solu- tion of potassium cyanide, ammonia-water, and boiling nitric acid, but insoluble in dilute acids, and does not readily change color on exposure to solar light; when strongly heated it is completely decomposed into metallic silver and cyanogen gas. If the acid is rendered slightly alkaline by potassium hydrate, a few drops of a solution of ferrous sulphate and ferric chloride added, and the mixture subsequently acidulated with hydrochloric acid, a pre- cipitate of ferric ferrocyanide or Prussian blue will be produced. Hydrocyanic acid may also be recognized by the following characteristic reactions. When neutralized with a dilute solution of potassium or sodium hydrate, a few drops of yellow ammonium sulphide added, and the mixture carefully evaporated in a porce- lain capsule to dryness, a residue is obtained which, when dis- solved in water, acidulated with hydrochloric acid, and filtered, yields on the addition of a drop of solution of ferric chloride an intense blood-red color. When the acid is neutralized with a dilute solution of potassium or sodium hydrate, a little picric acid added, and the mixture warmed, an intense blood-red color, due to the formation of picrocyanic acid, C8II5N506, is produced. If a solution of mercurous nitrate is added to a solution of hydro- cyanic acid, a gray precipitate of metallic mercury is at once pro- 160 MANUAL OF CHEMICAL ANALYSIS. duced, with the simultaneous formation of mercuric cyanide, which remains in solution. Examination: A small portion of the acid, when allowed to evaporate on a watch glass, should leave no residue. Mineral acids in general may be detected by producing a per- manent red coloration with litmus, as also by causing the precipi- tation of red mercuric iodide upon the addition of a solution of the double salt of mercuric cyanide and potassium iodide, IIgK(CN)2I,* the latter being decomposed by all acids, with the exception of hydrocyanic and carbonic acids. Hydrochloric and phosphoric acids may be detected by the addition of an excess of ammonia-water, and evaporating the solution in a porcelain capsule, at a gentle heat, to dryness; the residue is dis- solved in dilute nitric acid, and a portion of the filtered solution examined with argentic nitrate for hydrochloric acid, which is in- dicated by a white precipitate. To another portion of the solu- tion ammonium molybdate is added, and heated to boiling; an ensuing yellowish precipitate indicates phosphoric acid. Formic acid, if present, will be detected by its property of reducing red oxide of mercury to gray metallic mercury, when a little of the acid is warmed and agitated with the oxide; or by the reduction of metallic silver on the addition of a solution of argentic nitrate, which will impart a grayish color to the precipi- tated argentic cyanide. Sulphuric acid is detected by the formation of a white precipi- tate upon the addition of a few drops of barium nitrate to the acid. Estimation of the Strength of Hydrocyanic Acid: There are two simple methods of ascertaining the quantity of absolute acid contained in hydrocyanic acid. The one depends upon the fact that one part of absolute hydrocyanic acid forms 5 parts of argentic cyanide; that, accordingly, 100 parts of the officinal acid should yield 10 parts of argentic cyanide. The second method is the volumetric one, and depends upon the property of argentic cyanide to form a soluble double salt with alkaline cyanides. When, therefore, the officinal hydro- cyanic acid is converted into sodium or potassium cyanide by the addition of sodium or potassium hydrate, no permanent precipi- tate will appear upon the addition of argentic nitrate until more than sufficient argentic cyanide is produced to form the soluble compound. I. Ten grams of the acid are completely precipitated by a solu- tion of argentic nitrate. Then two filters of exactly the same size and paper are cut; through the one the liquid is filtered, the pre- * Obtained by mixing hot concentrated alcoholic solutions of 3 parts of mer- curic cyanide and 2 parts of potassium iodide ; the compound crystallizes out upon cooling, and may be dissolved in water for use. ACID A 161 cipitate washed, and then both the empty filter and the one con- taining the argentic cyanide are dried, at a temperature not exceeding 100° C. (212° F.). When the weight of the latter filter remains constant, both filters are weighed, the empty one serving as a counterpoise of the one containing the precipitate; the excess of weight of the latter is argentic cyanide, of which— 1. gram represents 2.015 per cent, of absolute hydrocyanic acid. 1.05 “ “ 2.10 “ “ “ “ 1.10 “ “ 2.20 “ “ “ “ II. The principle involved in the volumetric estimation of hydrocyanic acid has been fttlly described on page 100. 5.4 grams of the acid are accurately weighed, and diluted, in a beaker, with about 200 cubic centimeters of water. The liquid is then made slightly alkaline with a solution of potassium or sodium hydrate, a few drops of a saturated solution of sodium chloride added, and a decinormal solution of argentic nitrate (page 98) allowed to flow into the liquid from a burette until, with constant stirring, a slight permanent turbidity is produced in the solution. The number of cubic centimeters of silver solution required to produce this reac- tion with the above-mentioned quantity of acid, divided by 10, will give at once the percentage strength of the acid in hydrogen cyanide. Separation and Detection of Hydrocyanic Acid in Forensic Inves- tigations.—Hydrocyanic acid, being one of the most formidable of poisons, is sometimes the object of search in forensic investiga- tions, and the process for its isolation, and subsequent recognition and estimation will, therefore, be briefly described. The organic materials or substances to be examined are brought into a flask, a little water added, if necessary, and the mixture slightly acidulated with tartaric acid. A preliminary test is then first made by inserting in a cork adapted to the flask containing the mixture a small strip of paper, moistened first with a little tincture of guaiac, and, after drying, with a very dilute solution of cupric sulphate,* and subsequently gently warming the mix- ture to about 50“ C. (122° F.). In the presence of the vapor of hydrocyanic acid the paper will assume a deep blue color. As, however,-other substances, ammonia, nitric oxide, etc., are capable of producing a similar blue coloration, this reaction does not afford unqualified proof of the presence of hydrocyanic acid; and when thus indicated by the above reaction, or by the odor of the mix- ture under examination, the isolation and identification of the acid must in all cases be effected. * The tincture of guaiac is best freshly prepared, in the proportion of one part of the wood to ten parts of alcohol, or one part of the resin to twenty parts of alcohol ; the solution of cupric sulphate in the proportion of one part of the salt to two thousand parts of water, by which dilution it forms a perfectly colorless solution. 162 MANUAL OF CHEMICAL ANALYSTS. The substance to be examined, therefore, after acidulation with tartaric acid, and dilution, if necessary, with water, is subjected to distillation in a flask or retort, provided with a condenser, and the distillate collected in a receiver containing a little water (Fig. 72); Fig. 72. the distillation being continued until about one quarter or one- third of the liquid has distilled over. The distillate is then examined by its odor, action upon litmus, and by the application of the previously described reactions, viz., the formation of argen- tic cyanide, Prussian blue, and ferric sulphocyanide. If a quanti- tative estimation of the acid is required, it may be converted into argentic cyanide, by the addition of solution of argentic nitrate to the distillate until a precipitate ceases to be produced, and from the argentic cyanide, dried at 100° C. (212° F.) until of constant weight, the amount of pure hydrocyanic acid calculated: 100 parts of argentic cyanide corresponding to 20.15 parts of absolute hydrocyanic acid. As the distillate, however, may contain hydro- chloric acid in addition to hydrocyanic acid, the former should be tested for, and, when present, must be eliminated by the rectifica- tion of the distillate over a little powdered borax or precipitated calcium carbonate, previous to its precipitation with argentic nitrate; these substances serving to combine the free hydrochloric acid, but are not acted upon by hydrocyanic acid, which is thus obtained in a pure form. In view of the possibility of the occurrence of potassium ferro- cyanide in the substance under examination, which would also yield hydrocyanic acid by distillation with an acid, and of the fact that it is a non-poisonous salt, the examination should be in- variably preceded by a test for ferrocyanides, by digesting a por- A C I D A 163 tion of the substance with water, filtering the solution, and, after acidulating with hydrochloric acid, applying the well-known reaction with ferric chloride. For the separation of potassium ferrocyanide when associated with hydrocyanic acid, or a soluble simple cyanide, the organic materials, if not already possessing an acid reaction, should be first slightly acidulated with sulphuric acid, and then sufficient of a neutral solution of ferric chloride added to precipitate the entire amount of ferrocyanide as Prus- sian blue. After standing for some time the mixture is filtered, and the filtrate, after the addition of a sufficient quantity of neu- tral potassium tartrate to insure the complete combination of the free sulphuric acid, is subjected to distillation. By operating in this manner the distillate can only contain hydrocyanic acid when originally present as such, or in the form of potassium cyanide. ACIDUM HYFOPHOSPHOROSUM. Ger. TJnterpliosphorigesaure ; Fr. Acide liypopliosplioreux ; Sp. Acido hipofosforico. Hypophosphorous Acid. /OH II3P02 = ; 66. XH A dense, syrupy, strongly acid liquid, which, at low tempera- tures, forms large, colorless laminar crystals. The crystals melt at 17.4° C. (63.3° F.), and deliquesce gradually at ordinary tem- peratures. By exposure to the air it becomes slowly oxidized to phosphorous acid, and by the action of chlorine or nitric acid it is converted into phosphoric acid. Hypophosphorous acid in its aqueous solution possesses strongly reducing properties, precipitating gold and silver from solutions of their salts, and, when added to a solution of mercuric chloride, either mercurous chloride or metallic mercury is separated, ac- cording to the amount of acid present. When the acid, in excess, is gently warmed with a few drops of solution of cupric sulphate, at a temperature not exceeding 60° C. (140° F.), a reddish-brown precipitate of cupric hydride, Cull, is produced; with an excess of the cupric solution, and upon more strongly heating, metallic copper is separated. The acid, when strongly heated, is decomposed into hydrogen phosphide and phosphoric acid: 2H3P02 = PH3 + H3P04. Examination: Lead and Calcium Salts and Phosphoric Acid.—A small portion of the acid is neutralized with ammonia-water, and is then tested, in separate portions, as follows: A dark coloration or precipitate 164 MANUAL OF CHEMICAL ANALYSIS. on the addition of ammonium sulphide will indicate lead, a white precipitate on the addition of ammonium oxalate, calcium salts, and a white precipitate with barium chloride, phosphoric acid. Hydroyen sulphide may be recognized by a dark coloration on the addition of a solution of plumbic acetate. ACIDUM LACTICUM. Lactic Acid. Oxy-propionic Acid. Ger. Milclisaure ; Fr. Acide lactique ; Sp. Acido lactico. C,H,0, = CHs-CH<^_oh; 90. A limpid, odorless, syrupy liquid, colorless, or of a pale-yellow- ish tint, of a sour taste, and having the specific gravity 1.212 at 15° C. (59° F.), corresponding to 75 per cent, of absolute lactic acid. It is miscible, in all proportions, with water, glycerin, alcohol, and ether, and also, without being colored, with cold, concentrated sulphuric acid. Lactic acid dissolves zinc and iron, with efferves- cence, and cannot be distilled without undergoing partial decom- position. Heated upon platinum-foil, it emits inflammable vapors, which burn with a pale flame, leaving a carbonaceous residue, which is completely dissipated at a red heat. When heated with a solution of potassium permanganate, lactic acid emits the odor of aldehyde. Examination: Gum, Mctnnite, and Glucose.—A few drops of the acid are diluted with water in a test-tube, and slightly supersaturated with sodium carbonate; to the clear liquid are added a few drops of Fehling’s solution, and the whole gently warmed; a blue coagulation upon the addition of the cupric solution before warming, would indi- cate the presence of gum; a brick-colored precipitate, after heating, indicates glucose. The presence of gum and mannite may also be recognized by the occurrence of a turbidity upon dropping the acid into a mix- ture of equal parts of alcohol and ether. Glycerin may be detected by mixing, in a porcelain capsule, a small portion of the acid with a slight excess of zinc oxide, pre- viously triturated with a little water; the whole is then evaporated, upon a water-bath, to dryness, the residue treated with strong alcohol, and the obtained alcoholic solution evaporated upon a watch-glass; a neutral, syrupy, sweet residue would indicate glycerin. Sarcolcictic acid may be detected by an ensuing blue precipitate, when tested with a solution of cupric sulphate. ACIDA 165 Foreign Organic Acids.—Two drops of the lactic acid are added in a test-tube to so much lime-water that the alkaline reaction predominates; if a turbidity takes place at once, oxalic, tartaric, or phosphoric acids are indicated; if the turbidit}7 does not ensue before the liquid is heated to boiling, citric acid is indicated. Acetic and butyric acids are recognized by their respective odors when the acid is gently heated in a porcelain capsule. Sulphuric, hydrochloric, and phosphoric acids may be detected in the diluted aqueous solution of the acid by testing it, in separate portions, with barium chloride for the former, and with argentic nitrate for the two latter. Acid calcium phosphates or other calcium salts would be indi- cated by a white turbidity of the dilute solution of the acid when tested with ammonium oxalate. Metals are detected in the acid, when neutralized with ammonia- water, and then tested with hydrogen sulphide; a white turbidity or precipitate would indicate zinc, a brown or blackish coloration or precipitate, copper, lead, or iron. Estimation: Ninety parts by weight of the officinal acid should be neutral- ized by not less than seventy-five parts bv weight of crystallized potassium bicarbonate, corresponding to 75 per cent, of absolute lactic acid. The acid may be also estimated volumetrically by the process of neutralization, whereby 6 grams of the officinal acid should require for exact neutralization 50 cubic centimeters of a normal solution of potassium or sodium hydrate, which like- wise corresponds to 75 per cent, of absolute acid. By the employ- ment of other quantites of the acid than that above indicated, the calculation may be made with the consideration that 1 cubic cen- timeter of normal potassium or sodium hydrate corresponds to 0.09 gram of absolute lactic acid. ACIDUM NITRICUM. Nitric Acid. Ger. Salpetersaure ; Fr. Acide nitrique ; Sp. Acido nitrico. Nitric acid, in its most concentrated form, is a colorless, faming, corrosive liquid, having the spec. grav. of 1.530 at 15° 0. (59° F.). It begins to boil at 86° C. (186.8° F.), and becomes of a dark-yellow color, due to the partial decomposition of the acid into nitrogen tetroxide, oxygen, and water. When a strong acid is subjected to distillation, it loses nitric acid, and the boiling point is gradually increased until, at the temperature of 120.5° 0. (248.9° F.), an acid of constant composition distils over; a weak acid, under the same conditions, loses water until, at 120.5° C. 166 MANUAL OF CHEMICAL ANALYSIS. (248.9° F.), the boiling point remains constant. This acid having a constant boiling point has the spec. grav. of 1.414 at 15.5° C. (60° F.), and contains 68 per cent, of absolute nitric acid. The crude commercial nitric acid is of two strengths: the so- called double acid has a spec. grav. of 1.86, containing about 57 per cent, of absolute nitric acid; and the single acid, of 1.22 spec, grav., containing about 85 per cent, of absolute acid. The officinal nitric acid has the spec. grav. of 1.420 (1.185 Pharm. Germ. = 30 per cent. HN03), and contains 69.4 per cent, of absolute nitric acid. The Acidum Nitricum Dilutum, of 1.059 spec. grav. (1.101 Brit. Pharm. = 16.8 per cent. IIN03), contains 10 per cent, of absolute nitric acid. Nitric acid is readily decomposed, and is a powerful oxidizing agent, acting violently upon most of the metals, and upon organic compounds, converting many non-nitrogenous vegetable sub- stances into explosive bodies. From its tendency to decompose, nitric acid has frequently a yellowish color from nitrogen oxides, held in solution, which, upon dilution of the acid with water, or upon heating, cause a further decomposition and consequent dis- engagement of nitric peroxide. Nitric acid may be recognized by its property of dissolving copper-turnings to a blue solution, with the evolution of colorless nitric-oxide gas, which, however, at once unites with atmospheric oxygen, forming red fumes of nitric peroxide; by the ready decoloration of diluted solution of indigo; by its coloring pine-wood bright yellow ; and by deep red or brown compounds with ferrous salts. An exceedingly delicate test for nitric acid depends upon its reaction with the alkaloid brucine. A few drops of concentrated sulphuric acid, and one or two drops of a saturated aqueous solution of brucine, are added to the solution to be tested, when a fine rose or dark-red coloration will be produced. By means of this reaction a solution containing but one part of nitric acid in 100,000 parts of water will assume a distinct pink coloration. Another excellent test, but somewhat less delicate than the preceding, depends upon the reaction of nitric acid with aniline. About 0.5 cubic centimeter (approxi- mately 5 drops) of a solution of 10 drops of aniline in 50 cubic centimeters of 15 per cent, sulphuric acid (Acid. Sulph. Dil., U. S. P., may be employed) is brought into a small porcelain capsule, and a glass rod, moistened with the liquid to be tested, is then brought in contact with the liquid. If the nitric acid be very dilute, a rose-red coloration will be produced, but, if concentrated, the entire liquid will assume a browa or dark brownish-red tint. The characteristic reaction of nitric acid with ferrous salts ex- tends also to the nitrates, when previously acted upon by strong sulphuric acid. The test is performed either by placing a crystal of ferrous sulphate in the liquid under examination, mixed with concentrated sulphuric acid, or by mixing the liquid with a con- centrated solution of ferrous sulphate, and pouring this mixture AC ID A 167 carefully upon concentrated sulphuric acid in a test-tube, so as to form in either case two layers (Fig. 73). If a large quantity of nitric acid is present, the surfaces of the crystal, or the line of contact between the liquids, become black; if but a small quan- tity is present, they become reddish-brown or purple. Fig. 73. Examination: Hydrochloric acid may be detected in tbe acid diluted with about five times its volume of water, by the formation of a white preci- pitate, when tested with argentic nitrate. Sulphuric acid is detected in the acid, previously diluted with at least five times its volume of water, by the production of a white precipitate, either immediately or upon standing, on the addition of a solution of barium nitrate. Nitrous and hyponitric acids (nitrogen tetroxide) are detected in the diluted acid, by the addition of one or two drops of a very dilute(1:100) solution of potassium permanganate: their presence is indicated by decoloration. They may also be recognized by add- ing to the acid, previously diluted with about five times its volume of water, a few drops of a solution of potassium iodide, and a little mucilage of starch, when a blue coloration will be produced. Iodine and Iodic Acid.—A small portion of the acid (the con- centrated acid should be diluted with about five times its volume of water) is shaken, in a test-tube, with a few drops of chloro- form, which, after subsiding, will appear of a reddish-violet color if free iodine be contained in the acid; when it remains colorless, or after the removal of the free iodine, if present, by agitation with chloroform, a very small quantity of an aqueous solution of hydrogen sulphide or sulphurous acid is added, drop by drop, 168 MANIIAL OF CHEMICAL ANALYSIS. with gentle agitation; if a coloration of the chloroform now takes place, iodic acid is indicated. A confirmatory test is, to mix the acid, after dilution, if strong acid is under examination, with a few drops of mucilage of starch; a bluish coloration will take place after a while, when iodine is present; if no reaction occurs, a few drops of solution of sulphur- ous acid may be added, drop by drop, when the blue color will appear, if iodic acid be present. Metals may be detected by saturating the diluted acid with hydrogen sulphide, when an ensuing dark coloration or precipi- tate will indicate lead or copper; the liquid is then filtered, if necessary, and supersaturated with ammonia-water; if a dark coloration is now produced, it will indicate iron. Arsenic, in the form of arsenic acid, is detected by neutralizing a portion of the acid with solution of potassium hydrate, subse- quently adding twice its volume of a strong solution of potassium hydrate and a few fragments of pure zinc, and heating the mixture in a test-tube, provided with a cap of bibulous paper moistened with a drop of solution of argentic nitrate (Fig. 74); the production of a black stain upon the paper will reveal the pres- ence of arsenic. Estimation: The estimation of nitric acid is most conveniently ac- complished volumetric-ally by the process of neutraliza- tion. About 5 grams of the acid, accurately weighed in a beaker, are diluted with about 50 cubic centime- ters of water, a few drops of litmus solution added, and a normal solution of potassium or sodium hydrate (page 87) allowed to flow into the liquid from a burette until, with constant stirring, the liquid assumes a per- manent blue tint. One cubic centimeter of the normal alkali solution corresponding to 0.068 gram FIN03, the amount of absolute acid in the quantity employed, and its percentage strength, may readily be calculated. In addition thereto the specific gravity of the acid may be determined, and the result of the volumetric tion compared with the percentage strength of an acid having a corresponding specific gravity, as indicated by the subjoined table, page 170. Of the strong officinal acid 4.54 grams, and of the diluted acid 31.5 grams, are neutralized by 50 cubic centimeters of normal solution of potassium or sodium hydrate. Fig. 74. ACIDA 169 Rules for the Dilution of Nitric Acid. If a strong acid, a, has to be diluted with water, or with a weaker acid, c, in order to obtain an acid of some special strength, b, the following rules are applicable: The difference in percentage strength is sought, on the one hand, between a and b, and, on the other, between b and c, and a and c are then mixed in the proportions represented by the difference in the respective numbers. It must be observed, however, that when the difference between a and b is greater than between b and c, less of a than of c must be taken in order to obtain b; and when the difference between a and b is less than between b and c, more of a than of c must be employed in order to obtain b; for example: I. Nitric acid, containing 29 per cent, of absolute acid, is to be mixed with water, to form an acid containing 25 per cent, of absolute acid: a. b. c. 29 per cent. 25 per cent. 0 per cent. 4 25 Difference 25 parts of 29 per cent, acid are, therefore, to be mixed with 4 parts of water, or 100 grams of nitric acid = 29 grams 1IN03 16 “ “ water = 116 grams of nitric acid = 29 grams HN03 100 “ “ “ “ =25 “ “ or II. Nitric acid, containing 32 per cent, of absolute acid, is to be mixed with an 8 per cent, acid, to form an acid containing 14 per cent, of absolute acid: a. b. c. 32 per cent. 14 per cent. 8 per cent. 18 6~~ (3) (1) Difference 1 part of 32 per cent, acid is, therefore, to be mixed with 3 parts of 8 per cent, acid, or 100 grams of nitric acid = 32 grams NH03 800 “ “ “ “ = 24 “ “ 400 grams of nitric acid = 56 grams HN03 100 “ “ u 11 =s 14 “ u or 170 MANUAL OF CHEMICAL ANALYSIS. Table of the quantity by weight of absolute Nitric Acid, and the cor- responding equivalent of Nitric Anhydride, contained in 100 parts by weight of Nitric Acid, of different specific gravities. Specific gravity. Per cent, of hno3 Per ct. of N206. Specific gravity. Per ct. of H.\03. Per cent, of N205. Specific gravity. Per ct. of hno3. Per cent, of n2o5. 1.530 100.00 85.71 1.435 73.00 62.57 1.298 47.18 40.44 1.530 99.84 85.57 1.432 72.39 62.05 1.295 46.64 39.97 1.530 99.72 85.47 1.429 71.24 61.06 1.284 45.00 38.57 1.529 99.52 85.30 1.423 69.96 60.00 1.274 43.53 37.31 1.523 97.89 83 90 1.419 69.20 59.31 1.264 42.00 36.00 1.520 97 00 83.14 1.414 68.00 58.29 1.257 41.00 35.14 1.516 96.00 82.28 1.410 67.00 57.43 1.251 40.00 34.28 1.514 95.27 81.66 1.405 66.00 56.57 1.244 39.00 33.43 1.509 94.00 80.57 1.400 65.07 55.77 1.237 37.95 32.53 1.506 93.01 79.72 1.395 64.00 54.85 1.225 36.00 30.89 1.503 92.00 78.85 1.393 63.59 54.50 1.218 35.00 29.29 1.499 91.00 78.00 1.386 62.00 53.14 1.211 33.86 29.02 1.495 90.00 77.15 1.381 61.21 52.46 1.198 32.00 27.43 1.494 89.56 76.77 1.374 60.00 51.43 1.192 31.00 26.57 1.488 88.00 75.43 1.372 59.59 51.08 1.185 30.00 25.71 1.486 87.45 74.95 1.368 58.88 50.47 1.179 29.00 24.85 1.482 86.17 73.86 1.363 58.00 49.71 1.172 28.00 24.00 1.477 85.00 72.89 1.358 57.00 48.86 1.166 27.00 23.14 1.474 84.00 72.00 1.353 56.10 48.08 1.157 25.71 22.04 1.470 83.00 71.14 1.346 55.00 47.14 1.138 23.00 19.71 1.467 82.00 70.28 1.341 54.00 46.29 1.120 20.00 17.14 1.463 80.96 69 39 1.339 53.81 46.12 1.105 17.47 14.97 1.460 80.00 68.57 1.335 53.00 45.40 1.089 15.00 12.85 1.456 79.00 67.71 1.331 52.33 44.85 1.077 13.00 11.14 1.451 77.66 66.56 1.323 50.99 43.70 1.067 11.41 9.77 1.445 76.00 65.14 1.317 49 97 42.83 1.045 7.22 6.62 1.442 75.00 64.28 1.312 49.00 42.00 1 022 4.00 3.42 1.438 74.01 63.44 1.304 48.00 41.14 1.010 2.00 1.71 Temperature 15° C. (59° F.). With the decrease and increase of temperature, the specific gravity of nitric acid suffers a corresponding increase or decrease, amounting for each degree ol the centigrade thermometer in either direction : For acids of a specific gravity of 1.494 to those of 1.477 to 0.00213 in the average. “ “ “ “ 1.474 “ 1.456 ‘ 0.002 44 “ 4< 44 44 44 1.456 44 1.435 ‘ 0.00186 “ 44 44 (4 44 44 1.429 44 1.410 ‘ 0.00171 “ 44 v 4k 44 44 44 1.405 44 1.381 ‘ 0.00155 “ 4 4 44 44 44 44 1.374 44 1.353 ‘ 0.00141 44 44 4 C 4 « 44 4 4 1.346 44 1.317 ‘ 0.00128 “ < 4 44 44 44 1.304 44 1.274 ‘0.00114 “ 4 4 44 44 44 44 1.274 44 1.237 ‘ 0.001 “ 4 4 44 44 44 4 4 1.237 1.198 4 0.00085 “ 44 44 44 44 1.192 44 1.166 4 0 00071 44 44 44 44 44 1.157 44 1.120 * 0.0005 44 4 4 For instance: An acid of 1.179 spec. grav. at 15° C., containing 24.85 per cent, of nitric anhydride, or 29.00 of absolute nitric acid, will have at 17.5° C. a spec. grav. of 1.179 — (0.00071 X 2.5) =1.1778, and at 13° C. a spec. grav. of 1.179+ (0.00071 x 2) = 1.1804. ACIDA 171 ACIDUM OLEICUM. ACIDUM OLEINICUM. Ger. Oelsaure ; Fr. Acide oleique; Sp. Acido oleico. Oleic Acid. W, = C„HB-CO-OH ; 282. An oily liquid, without odor or taste, and colorless or having but a slight yellow color. It solidifies at 4° C. (39° F.),to a com- pact, white crystalline mass, and from its solution in alcohol it crystallizes in brilliant white needles, which melt at 14° C. (57° F.)to a colorless oil. Its specific gravity is 0.808 at 19° C. (66° F.). When perfectly pure, and unoxidized, it is neutral in its action upon litmus, but on exposure to the air, especially when slightly impure, it rapidly absorbs oxygen, acquiring thereby a yellow or brownish-yellow color, a rancid taste and smell, and an acid reaction. When strongly heated, it becomes decomposed, but with super-heated steam it may be distilled unchanged at 250° C. (482° F.). By treatment with nitrous acid, oleic acid is converted into the solid isomeric elaidic acid, which crystallizes in laminae, melting at 44 to 45° C. (Ill to 113° F.). Oleic acid is insoluble in water, but freely soluble in alcohol, ether, chloroform, benzol, petroleum benzin, and the volatile and fatty oils; it is also soluble in cold, concentrated sulphuric acid without decomposition. Examination: Stearic and palmitic acids will be indicated by a higher con- gealing point than 4° C. (39° F.), and may be also detected by the following test: A portion of the acid is completely saponified by potassium carbonate, with the aid of a gentle heat, the result- ing soap dissolved in water, exactly neutralized with acetic acid, and the solution precipitated with plumbic acetate; the ensuing precipitate of plumbic oleate, after being twice washed with boil- ing water, should be completely or almost completely soluble in ether ; any considerable insoluble residue will indicate an undue proportion of an admixture of stearic or palmitic acids. Fixed oils, with the exception of ricinus or castor oil, may be detected by the formation of a turbid mixture or the separation of oily drops, when the acid is mixed with an equal volume of strong alcohol, and heated to 25° 0. (77° F.). Lead may be detected by a brown or blackish coloration or precipitate when the alcoholic solution of the acid is saturated with hydrogen sulphide. 172 MANUAL OF CHEMICAL ANALYSIS. ACIDUM OXALICUM. Ger. Oxalsaure ; Fr. Acide oxalique ; Sp. Acido oxalico, Oxalic Acid. CO-OH | CO-OII C2H204 + 2II20 = f 2H20; 126. Colorless, transparent, oblique-rhombic prisms (Fig. 75), con- taining two molecules (28 per cent.) of water of crystallization, which they lose gradually upon exposure in a warm and dry atmosphere, or quickly upon heating at 100° C. (212° F.), becoming reduced to a soft white powder. By cautiously heating at a temperature not exceeding 150° C. (302° F.), the anhydrous acid may be completely sublimed ; exposed to a strong heat it develops irritating inflamable vapors, and is resolved, without carbonization, into carbon di- oxide, carbon monoxide, formic acid, and water, and is finally completely dissipated. Oxalic acid is soluble in 14 parts of water at 15° C. (59° F.), and in its own weight or less of boiling water, in 6 to 7 parts of 90 per cent., and 4 parts of absolute, alcohol; it is also soluble in 7 parts of glycerin, but sparingly soluble in ether and chloroform. Its solution has a very sour taste, and a strong acid reaction ; it forms with the alkali metals soluble, with all other bases, for the most part, insoluble, salts, which, however, are soluble in dilute mineral acids. When a cold saturated aqueous solution of oxalic acid is dropped into strong alcohol, it should not produce a turbidity ; when dropped into lime-water, a copious white precipitate must ensue at once, which remains unchanged upon the addition of acetic acid, as well as of ammonium chloride, but which is readily dissolved by hydrochloric and nitric acids. Added to a solution of calcium sulphate, a precipitate is also produced after a while! When heated with concentrated sulphuric acid, oxalic acid is resolved into water and equal volumes of carbon monoxide and carbon dioxide gases, without being charred. Examination: Binoxalates and quadroxalates of potassium (sorrel and lemon salts) are detected by heating a small portion of the oxalic acid in a platinum or porcelain capsule, to redness, and until no more fumes are emitted; a white fused residue, turning red litmus- paper blue, and effervescing with a few drops of hydrochloric acid, would indicate potassium or traces of calcium. The crude commercial acid mostly leaves a very small trace of Fio. 75. A CID A 173 residue, too insignificant, however, to impair the quality of the acid, or to render it unfit for its common technical applications. Tartaric, citric, and racemic acids, and their salts, as accidental admixtures in oxalic acid, may be detected by gently heating a small quantity of the acid on platinum-foil, when they will be recognized by the development of a peculiar caramel-like odor, and a voluminous carbonaceous residue ; when heated, in a test- tube, with concentrated sulphuric acid, the crystals, as well as the sulphuric acid, must not become dark-colored or blackened, otherwise the presence of one or the other of such admixtures is indicated. The acid should dissolve perfectly in water, forming a clear solution, and, when saturated with hydrogen sulphide, should afford no coloration or precipitate. Estimation: Oxalic acid may be estimated volumetrically, either by the process of neutralization with a normal alkali, or by oxidation in its warm aqueous solution, slightly acidulated with sulphuric acid, with a standard or decinormal solution of potassium permanga- nate ; it being resolved by the latter, through absorption of oxygen, into carbon dioxide and water. I. Three grams of the air-dry, but uneffloresced, acid are dis- solved in about 50 cubic centimeters of water, and, after the addition of a few drops of litmus solution, a normal solution of potassium or sodium hydrate (page 87) is allowed to flow into the liquid from a burette until, with constant stirring, a permanent blue coloration is produced. Oxalic acid being dibasic, each cubic centimeter of alkali solution employed, corrected if necessary by its proper factor, corresponds to 0.063 gram of crystallized acid, from which the percentage amount of pure acid in the specimen under examination may be readily determined. II. 0.2 gram of the crystallized acid are dissolved in about 200 cubic centimeters of water, in a beaker, 5 to 10 grams of dilute sulphuric acid are then added, and, after gently heating, a standard solution of potassium permanganate (page 89) is allowed to flow into the liquid from a burette until, with constant stirring, a permanent pink coloration is produced. The reaction may be expressed as follows: C2H204 + 0 = 2C02 + H20. One atom of oxygen thus oxidizes one molecule of oxalic acid, and the same amount of oxygen would oxidize two atoms of iron from the ferrous to the ferric state : 2FeS04 + H2S04 -f 0 = Fe2(S04)3 -f H20. From these deductions one mole- cule of oxalic acid corresponds to two atoms (one molecule) of iron; and placing then the molecular weight of iron (112) as the first term, the molecular weight of crystallized oxalic acid (126) as the second term, and the amount of metallic iron, expressed in grams, corresponding to the number of cubic centimeters of per- 174 MANUAL OF CHEMICAL ANALYSIS. manganate solution employed, as the third term, a simple pro- portion will determine the amount of pure crystallized oxalic acid contained in the specimen under examination. ACIDUM PHOSPHORICUM. Phosphoric Acid. Ger. Phosphorsaure ; Fr. Acide pliospliorique ; Sp. Acido fosforico. Metaphosphoric Acid, HPOs = 0=P ; 80. /OH Orthophosphoric Acid, II.fP04 = 0=P/-0H ; 98. \QH Monobasic or metaphosphor ic acid, FIP03, when perfectly pure, forms a soft pasty mass, which, on exposure to the air, readily absorbs moisture, and deliquesces to a thick syrupy liquid. The glacial phosphoric acid (Acidum Phosphoricum (ilaciale) is an impure inetaphosphoric acid, containing frequently considerable amounts of sodium or calcium phosphates, and forms colorless, transparent, glass-like, fusible masses, deliquescent, and slowly but freely soluble in water and in alcohol, yielding colorless, ino- dorous, acid solutions. The aqueous solution of inetaphosphoric acid, when freshly prepared, produces white precipitates with albumen and with solutions of argentic nitrate and barium and calcium chlorides, which are soluble in an excess of the acid, while free orthophosphoric acid precipitates none of the above men- tioned reagents. When its solution is allowed to stand for some time, or by continued boiling, the monobasic acid is converted into the tribasic acid, which is contained in the medicinal Acidum Phosphoricum Dilutum. This process is accelerated by the ad- dition of a little nitric acid to the boiling solution of the mono- basic acid. Tribasic or orthophosphoric acid, H3P04, when free from water, forms an odorless and colorless, dense, syrupy liquid, possessing a strongly acid taste and reaction. On standing over sulphuric acid, or by exposure to cold, it crystallizes, forming six-sided prisms, terminated by six-sided pyramids, belonging to the rhombic system, which melt at 38.6° C. (101.5° F.), and readily become liquefied in the presence of a small amount of water. The specific gravity of the anhydrous acid is 1.88 at 15° C. (59° F.). At temperatures above 100° C. (320° F.) it loses water, and at 213° C. (415.4° F.) it is completely converted into pyrophos- phoric acid, H4P207; when heated to redness, the latter acid becomes in turn further decomposed, losing water, and metaphos- phoric acid, HP03, is produced. ACIDA 175 Orthophosphoric acid, as previously stated, when in the free state, does not precipitate albumen, nor a solution of argentic nitrate or barium chloride ; when carefully neutralized by ammo- nia-water, however, it yields a white precipitate with a solu- tion of barium chloride, soluble in nitric or hydrochloric acids; with argentic nitrate a yellow precipitate of argentic phosphate, soluble in nitric acid or ammonia-water, and with test magnesium mixture, a white crystalline precipitate of ammonio-magnesium phosphate. When heated with a solution of ammonium molyb- date, acidulated with nitric acid, a yellow crystalline precipitate of ammonium phosphomolybdate is produced. Two strengths of orthophosphoric acid are officinal :* Acidum Phosphoricum, containing 50 per cent, of absolute acid, and having a specific gravity of 1.847; and Acidum Phosphoricum Dilutum, containing 10 per cent, of absolute acid, and having a specific gravity of 1.057. Examination of Metaphosphoric Acid; Ammonium salts may be detected by heating a few fragments of the fused acid in a strong solution of potassium hydrate in a test-tube, when they will be recognized by the odor of ammonia, as also by the production of white fumes, when a glass rod, moist- ened with acetic acid, is held over the orifice of the tube. Calcium, magnesium, and aluminium salts may be detected by dissolving a small portion of the acid in water, boiling with a few drops of nitric acid, and, after the removal of the excess of nitric acid, carefully neutralizing with ammonia-water, when the phos- phates of calcium, magnesium, and aluminium will be precipitated. If a precipitate is thus obtained, it is separated by filtration, the filtrate reserved for subsequent examination for sodium or potas- sium salts, and the precipitate further examined as follows : It is first digested with a concentrated solution of potassium or sodium hydrate, the solution filtered, and to the filtrate solution of ammo- nium chloride added, when a transparent, flocculent precipitate will indicate aluminium. The portion of the precipitate insoluble in the alkaline hydrate is then dissolved in hydrochloric acid, an excess of a solution of sodium acetate, and subsequently a little ferric chloride added, until the liquid assumes a yellowish hue, heated to boiling, and filtered ; to a portion of the filtrate solution of ammonium oxalate is added, when a white precipitate will indi- cate calcium; to another portion of the filtrate ammonium carbo- nate in slight excess is added, the solution filtered, and to the fil- trate ammonium phosphate and ammonia-water then added, when a white crystalline precipitate will indicate magnesium. * The phosphoric acid of the Pharmacopoeia Germanica has a specific gravity of 1.120, corresponding to 20 per cent, of absolute acid ; and the diluted phos- phoric acid of the British Pharmacopoeia a specific gravity of 1.08, corresponding to 14 per cent, of absolute acid. 176 MANUAL OF CHEMICAL ANALYSIS. Sodium, or potassium salts may be detected in the filtrate from the precipitate produced by ammonia-water, as above described, by the following method: The phosphoric acid is first completely precipitated by neutral plumbic acetate, the filtrate freed from lead by hydrogen sulphide, filtered, and the filtrate evaporated and ignited. If a residue is thus obtained, it will contain the sodium or potassium salts in the form of carbonates, and may be further examined or identified by the color imparted to the non- luminous flame, when tested on platinum wire. Silicic acid may be detected by evaporating a portion of the solution of the acid, to which a small quantity of hydrochloric acid has been added, to dryness, with the aid of a gentle heat; the residue is then dissolved in water, slightly acidulated with hydro- chloric acid, when the silicic acid, if present, will remain behind as an insoluble granular powder. Metallic and other impurities may be detected by the methods described under orthophosphoric acid. Examination of Orthophosphoric Acid: Monobasic or metaphosphoric acid may be detected by a white precipitate on the addition of a solution of barium chloride, and by the formation of a gelatinous white precipitate when tested with solution of albumen. Phosphorous acid may be detected in the diluted acid by the addition of a few drops of a solution of argentic nitrate or mer- Fig. 76. curie chloride, and gently warming; a brown or blackish colora- tion or precipitate with the first reagent, and a grayish-colored precipitate with the latter, will indicate phosphorous acid. A dilute solution of the acid, to which one or two drops of a solution ACID A 177 of potassium permanganate is added, will also become readily decolorized on warming, if phosphorous acid is present. Hydrochloric acid is detected in the diluted acid, to which a few drops of concentrated nitric acid have been added, by a white precipitate on the addition of a solution of argentic nitrate. Nitric acid is indicated by ensuing decoloration when a little of the acid is gently heated with one drop of indigo-solution. Its presence may be confirmed by mixing with the acid nearly an equal bulk of concentrated solution of ferrous sulphate, and placing this mixture upon concentrated sulphuric acid, with the precaution that the two fluids do not mix (Fig. 76); a red-brown coloration upon the line of contact between the two fluids will confirm the presence of nitric acid. Sulphuric acid is detected in the diluted acid, to which a few drops of nitric acid have been added, by a white precipitate with barium nitrate. Metals are detected by saturating the diluted acid with hydrogen sulphide, and allowing the liquid to stand for 12 hours in a corked test-tube or flask; the occurrence of a coloration or precipitate will indicate metals;* a light-yellow, flocculent one, arsenic; a brown or black one, copper or lead. Arsenious as well as arsenic acid, besides having been detected in the test for metals with hydrogen sulphide, may be specially tested for by the application of Marsh’s test, as described on pages 33 to 35, or by the follow- ing modification of the same. To a small quantity of the dilute phosphoric acid, contained in a test-tube, one drop of solution of potassium permanganate is added, and the liquid gently warmed; if decoloration takes place, the addition of solution of permanganate is continued, drop by drop, until decoloration of the reagent ceases; dilute sulphuric acid and fragments of pure zinc (both of which should have been previously tested for arsenic) are then added, not allowing the liquid to occupy more than one-fourth of the capacity of the tube. A small cap of bibulous paper, previously moistened with a drop of solution of argentic nitrate, is then placed over the mouth of the tube (Fig. 77), and the reaction accelerated, if necessary, by gently warm- ing; the production of a purplish-black spot on the paper, due to the reduction of metallic silver, will con- firm the presence of arsenic. Estimation: The strength of officinal phosphoric acid may be ap- proximately determined by ascertaining its specific Fig. 77 * Upon long standing, a separation of sulphur, from the decomposition ot hydrogen sulphide, may ensue, but this may be readily recognized. 12 178 MANUAL OF CHEMICAL ANALYSIS. gravity, and subsequent reference to the subjoined table (page 180). Unlike most other acids, it cannot be estimated by direct neutralization with an alkali, since the point of neutralization, as indicated by means of litmus, cannot be distinctly observed, and in connection therewith is the fact of its forming three classes of salts—NaH2P04, which has an acid reaction, and Na2IiP04 and. Ua3P04, both of which possess an alkaline reaction. Among the various methods employed for the quantitative estimation of the officinal or orthophosphoric acid, the two fol- lowing will be found expedient and sufficiently accurate. I. Volumetric.—This method depends upon its indirect estima- tion by the process of neutralization. A convenient of the acid (about 10 grams of the officinal diluted acid, or 2 grams of the stronger acid) is accurately weighed, in a beaker, a normal solution of potassium or sodium hydrate (page 87) then allowed to flow in from a burette, until sufficient of the latter has been employed to insure the formation of the neutral sodium salt, Na3P04. To the strongly alkaline liquid a solution of barium chloride is then added until no further precipitate is produced, the resulting barium phosphate Ba3(P04)2, after being allowed to stand for a few hours, filtered off, the precipitate well washed with water, and the filtrate together with the washings collected in a beaker; after the addition of a few drops of litmus solution, a normal solution of oxalic or sulphuric acid (page 82) is allowed to flow into the liquid from a burette until, with constant stirring, a permanent pink tint is produced. The number of cubic centimeters of normal acid solution required, deducted from the number of cubic centimeters of alkali solution first employed, will give the amount of the latter required for the exact neutralization of the phos- phoric acid; one cubic centimeter of the normal alkali corre- sponding to 0.0327 gram II3P04, the percentage strength of the acid may be readily calculated. II. Gravimetric.•—About 10 grams of the officinal diluted acid, or about 2 grams of the stronger acid, are accurately weighed, in a beaker, ammonia-water, in slight excess, then added, and subse- quently test magnesium mixture, until, after having been well stirred and allowed to stand for a short time, no further precipi- tate is produced on the addition of the reagent. Ammonia-water, in an amount equal to about one-fourth of the volume of the liquid contained in the beaker, is then added, and the latter being covered, it is allowed to stand for about twelve hours. The precipitate of ammonio-magnesium phosphate is then collected on a filter, washed with a solution consisting of 1 part of ammonia-water and 3 parts of water until the washings no longer produce a turbidity in a solution of argentic nitrate acidulated with nitric acid, dried at 100° C. (212° F.), and finally ignited in a weighed porcelain cru- cible at a low, red heat. From the weight of the resulting mag- nesium pyrophosphate, Mg2P207, the amount of phosphoric acid A C ID A 179 contained in the solution, or the percentage strength of the same, is readily calculated : 100 parts of magnesium pyrophosphate cor- responding to 88.39 parts of phosphoric acid, H3P04, or 64.28 parts of phosphoric anhydride, P204. The U. S. Pharmacopoeia directs that on pouring 5 grams of the stronger acid upon 10 grams of plumbic oxide free from plumbic carbonate and from moisture, evaporating and igniting, the obtained residue should weigh 11.81 grams ; and that 5 grams of the diluted acid with 5 grams of plumbic oxide, under the same conditions, should yield a residue weighing 5.36 grams. Rules for the Dilution of Phosphoric Acid. If a strong acid, a, has to be diluted with water, or with a weaker acid, c, in order to obtain an acid of some special strength, 5, the following rules are applicable: The difference in percentage strength is sought on the one hand between a and and, on the other, between b and c, and a and c are then mixed in the proportions represented by the difference in the respective numbers. It must be considered, however, that wrhen the difference between a and b is greater than between b and c, less of a than of c must be taken in order to obtain b; and when the difference between a and b is less than between b and c, more of a than of c must be employed in order to obtain b; for example : I. Phosphoric acid, containing 45 per cent, of absolute acid, is to be mixed with water, to form an acid containing 10 per cent, of absolute acid: a. b. c. 45 per cent. 10 per cent. 0 per cent. 35 W~ Difference 10 parts of 45 per cent, acid are therefore to be mixed with 35 parts of water, or 100 grams of phosphoric acid = 45 grams H3P04 350 “ “ water = 450 grams of phosphoric acid = 45 grams H3P04 or 100 “ “ “ “ = 10 “ “ II. Phosphoric acid, containing 82 per cent, of absolute acid, is to be mixed with an 8 per cent, acid, to form an acid containing 10 per cent, of absolute acid: a. b. c. 82 per cent. 10 per cent. 8 per cent., 22 2 (11) (1) Difference 180 MANUAL OF CHEMICAL ANALYSTS. 1 part of 32 per cent, acid is therefore to be mixed with 11 parts of 8 per cent, acid, or 100 grams of phosphoric acid = 32 grams II3P04. 1100" “ “ “• “ = 88 “ 1200 grams of phosphoric acid = 120 grams Ii3P04. 100 “ “ “ “ = 10 “ “ Table of the quantity by weight of Orthophosphoric Acid, and the cor- responding amount of Phosphoric Anhydride, contained in 100 parts by weight of aqueous Phosphoric Acid of different specific gravities (Schiff). Temperature 15° C. (59° F.). Specific gravity. Per ct. of h3po4. Per cent, of P206. Specific gravity. Per ct. of j h3po4. j Per cent. of P,Os. Specific gravity. Per ct. of H«P04. Per cent, of P205. 1.0054 1 0.726 1.1262 21 15.246 1.2731 41 29.766 1.0109 2 1.452 1.1329 22 15.972 1.2812 42 30.492 1.0164 3 2.178 1.1397 23 16 698 1.2894 43 31.218 1.0220 4 2.904 ! 1.1465 24 17.424 i 1.2976 44 31.944 1.0276 5 3.630 1.1534 25 18.150 1.3059 45 32.670 1.0388 6 4 356 1.1604 26 18.876 1.3143 46 33.496 1.0390 7 5.082 1.1674 27 19 602 1.3227 47 34.222 1.0449 8 5.808 1.1745 28 20.328 1 3313 48 34.948 1.0508 9 6.534 1.1817 29 21.054 1 1.3399 49 35.674 1.0567 10 7.260 j 1.1889 30 21.780 1 1.3486 50 36.400 1.0627 11 7.986 1.1962 31 22.506 ! 1.3573 51 37.126 11.0688 12 8.712 1.2036 32 23.232 j 1.3661 52 37.852 1.0749 13 9.438 ! 1.2111 33 23.958 | 1.3750 53 38 578 1.0811 14 10.164 1.2186 34 24.684 1.3840 54 39.304 1.0874 15 10.890 1.2262 35 25.410 1.3931 55 40.030 1.0937 16 11.616 1.2338 36 26.136 1.4022 56 40.756 1.1001 17 12.342 1.2415 37 26.862 1.4114 57 41.482 1.1065 18 13.068 1.2493 38 27.588 1.4207 58 42.208 1.1130 19 13.794 1.2572 39 28.314 1.4301 59 42.934 1.1196 20 14.520 1 1.2651 40 29.040 ; 1.4395 60 43.660 With the decrease or increase of temperature, the specific gravity of phos- phoric acid suffers a corresponding increase or decrease, amounting for each degree of the centigrade thermometer in either direction : For acids of a specific gravity of 1.0567 to those of 1.1196 to about 0.00085 “ “ “ “ 1.1262 “ 1.1889 “ 0.00040 “ “ “ “ 1.1962 “ 1.2651 “ 0.00052 “ “ “ “ 1.2781 “ 1.3486 “ 0.00068 “ “ “ “ 1.3573 “ 1.4395 “ 0.00082 For instance: An acid of 1.1262 spec. gray, at 15° 0., containing 15.246 per cent, of phosphoric anhydride or 21 per cent, of phosphoric acid, will have at 200 C. a spec. gray, of 1.1262 — (0.0004 x 5) = 1.1242, and at 13° C. a spec. gray, .of 1.1262 -1- (0.0004 x 2) = 1.127. A C 11) A . 181 ACIDUM SALIC YLICUM. Salicylic Acid. Ortho-oxybenzoic Acid. Ger. Salicylsaure; Fr. Acide salieylique ; Sp. Acido salicilico. 0,11.0, = CnII 4\q0-0II ; 138- Fine, light, colorless needles, or four-sided prisms (Fig. 78), odorless, or having but a slight aromatic odor, and permanent in the air. They fuse at 156° C. (312.8° F.), and when carefully heated may be sublimed without decomposition; when quickly or more strongly heated, they are resolved into carbon dioxide and phenol, a de- composition which takes place to a slight extent when aqueous solutions of the acid are boiled ; when strongly heated on platinum-foil they are completely dissipated. Salicylic acid is soluble in 450 parts of water, and in 2.5 parts of alcohol at 15° C. (59° F.); in 14 parts of boiling water, and very freely in boil- ing alcohol; in 2 parts of ether or absolute alco- hol, in 3.5 parts of atnylic alcohol, and in 80 parts of chloroform; and sparingly soluble in benzol, carbon bisulphide, glycerin, and the vol- atile and fatty oils; it is readily soluble in solu- tions of the alkaline hydrates, forming crystal- lizable salts; and is also soluble in cold, concen- trated sulphuric acid, without coloration, being precipitated from the latter solution unchanged on the addition of water. The solubility of the acid in water is greatly increased by the presence of various salts, such as the alkaline carbonates and acetates, borax, etc., which form with the acid readily soluble compounds. The aqueous solution of the acid has an agreeable, somewhat sweetish taste, and an acid reaction, and assumes with a trace of ferric chloride an intense violet color; this reaction, however, is modified by the presence of alkaline hydrates, carbonates, acetates, and phosphates, as also by borax, potassium iodide, oxalic, citric, tartaric, phosphoric, and arsenic acids. With bromine-water the aqueous solution yields a white precipitate of bromo-salicylic acid, C7H5Br03. If to an aqueous solution of salicylic acid, or pre- ferably a perfectly neutral solution of its sodium salt, a solution of cupric sulphate be added, a bright emerald-green color is pro- duced, but which is destroyed by the presence of free alkalies or acids. Fig. 78. Examination: Fixed impurities may be recognized by a non-volatile residue when a small portion of the acid is strongly heated on platinum- foil. 182 MANUAL OF CHEMICAL ANALYSIS. Organic admixtures may be detected by the separation of car- bon when a little of the acid is heated on platinum-foil, or in a dry test-tube; or by a dark coloration when a small portion of the acid is agitated with about fifteen times its weight of cold, concentrated sulphuric acid. Chlorides or hydrochloric acid may be detected by an ensuing white precipitate when a little of the acid, dissolved in about ten times its weight of alcohol, and acidulated with nitric acid, is tested with solution of argentic nitrate. Phenol or carbolic acid may in most instances be detected by its odor; smaller quantities may be readily recognized by agitating the acid with a small quantity of warm water, and, after being allowed to cool, and the addition of a little ammonia-water, exposing the solution to the vapor of bromine, when a deep blue coloration will be produced; or, about 5 cubic centimeters of a saturated solution of salicylic acid are poured into a test- tube, in which 2 cubic centimeters of strong hydrochloric acid and a little granular potassium chlorate have just been mixed; some ammonia-water is then, by means -of a pipette, carefully placed upon the mixture; the former will assume a reddish or brownish tint, if carbolic acid be present. Detection of -Salicylic Acid in Syrups, Extracts, Articles of Food, etc.: A sufficient quantity of the substance to be examined is mixed or diluted with water, if necessary, and evaporated at a gentle heat, in order to expel any alcohol which may be present. After being allowed to cool, the clear filtered liquid is strongly acidu- lated with sulphuric acid, and subsequently shaken with ether. The ether is then carefully separated from the aqueous liquid, allowed to evaporate spontaneously, and the residue dissolved in a little water and tested with ferric chloride; if salicylic acid be present a deep violet coloration will be produced. ACIDUM SUCCINICUM. Ger. Bernsteinsaure ; Fr. Acide succinique ; Sp. Acido succinico. Succinic Acid. CH2-CO-OH C4II604 = I ; 118. CH2-CO-OH Colorless, oblique-rhombic prisms, or rhombohedral plates, with- out odor when pure, and with a more or less strong odor when the acid is obtained from amber by sublimation, and is only imperfectly freed from the empyreumatic oils. It melts at 180° C. (356° F.), but may be sublimed at a much A 01D A 183 lower temperature, and boils at 235° C. (455° F.), at the same time undergoing decomposition into water and succinic anhydride. When heated upon platinum-foil, it emits irritating, inflammable vapors, without the separation of carbon, and is entirely dissi- pated at a red heat. Succinic acid is soluble in 18 parts of water at 17° C. (62.6° F.) and in 0.8 part of boiling water, in 10 parts of cold 90 per cent, alcohol, in 1.5 parts of boiling alcohol, and in 80 parts of pure ether, but is insoluble in carbon bisulphide, petroleum benzin, and turpentine oil (distinction from benzoic acid); it is also soluble in warm nitric acid, and in concentrated sulphuric acid, without de- composition, and, if perfectly pure, produces with the latter no coloration. The aqueous solution of the acid has an acid taste and reaction, and, when carefully neutralized with ammonia-water, yields on the addition of a solution of ferric chloride a reddish-brown, floc- culent precipitate of basic ferric succinate, which is dissolved upon the addition of hydrochloric acid (further distinction from benzoic acid). Examination: Fixed Admixtures.— If a residue remains when the acid is heated upon platinum-foil, a small portion of it should be com- pletely incinerated in a porcelain crucible, and the residue, when cold, tested with moist turmeric- as well as with red litmus-paper. It is then divided into two parts, one of which is mixed with a little strong alcohol, and this ignited; a green color of the flame, especially toward the termination of the ignition, indicates boracic acid; the second portion of the residue is dissolved in a small quantity of water acidulated with a few drops of nitric acid; effer- vescence would indicate carbonates, originally present as such, or produced by the decomposition of some organic salts, if carboniza- tion occurred upon ignition. The acid solution is then tested in separate portions, with argentic nitrate for chlorides, and with barium nitrate for sulphates, which will be indicated in either instance by an ensuing white precipitate. Ammonium salts are detected by the odor of ammonia, and by white fumes when a glass rod, moistened with acetic acid, is held over the orifice of the test-tube, when the acid is heated in solu- tion of potassium hydrate. Foreign organic acids may be detected as follows: Tartaric acid will be indicated by a white crystalline precipitate of acid ammonium tartrate, upon partial saturation of the acid with ammonia-water; or, by the production of a white crystalline precipitate of acid potassium tartrate, upon the addition of a few drops of a concentrated solution of potassium acetate to the aqueous solution of the acid. Oxalic acid will be detected in the aqueous solution of the acid, after neutralization with ammonia-water, and the addition of a 184 MANUAL OF CHEMICAL ANALYSIS. solution of calcium chloride, calcium sulphate, or lime-water, by the formation of a white precipitate, which is insoluble in acetic acid, or a solution of ammonium chloride. Citric acid will be detected by the addition of a few drops of a solution of the acid to an excess of lime-water, so that the alka- line reaction still predominates, and subsequently heating to boiling; an ensuing white precipitate will indicate citric acid. Benzoic acid may be detected by its solubility in carbon bisul- phide or warm petroleum benzin; or by its separation, when the precipitate produced in the neutralized solution of the acid by ferric chloride is digested with a little hydrochloric acid. Sugar may be detected, in the absence of other organic acids or their salts, by a corbonaceous residue on gently heating a little of the acid on platinum-foil; and, in the presence of other organic acids, by heating a small portion of the solution with a few drops of dilute sulphuric acid, and subsequently testing with Fehling’s solution, when a red precipitate of cuprous oxide will be formed. Metallic impurities may be detected in the concentrated solution of the acid, by a dark coloration or a precipitate upon saturation with hydrogen sulphide, or upon subsequent supersaturation with ammonia-water. The following may serve as a general test for the purity of succinic acid : 1 part of the acid is dissolved in 15 parts of strong or absolute alcohol; the solution is aided by dipping the test-tube in hot water ; when cold it is divided into two parts, one of which is mixed with an equal volume of chloroform, the other with an equal volume of ammonia-water; a complete solution must take place in the first test, and a clear mixture in the second, otherwise one or more of the above-mentioned adulterations are present. When a crude acid, containing empyreumatic substances, has to be examined, it is first agitated and washed with a little ether, and is then dissolved in boiling water, and the solution, when cold, passed through a filter previously moistened with water. ACIDUM SULPHURICUM. Sulphuric Acid. Ger. Schwefelsaure ; Fr. Acide sulfurique ; Sp. Acido sulfuvico. H2S04 = 98. A dense, colorless, inodorous, highly corrosive liquid, of a spec, grav. of 1.8426 at 15° C. (59° F.). When the pure acid of the above composition is heated, it is partially decomposed into water and sulphur trioxide. This dissociation increases with increase of temperature, until at 838° C. (640.4° F.) a liquid acid of con- stant composition and boiling-point distils over without further ACIDA 185 alteration, which contains from 98.4 to 98.8 per cent, of abso- lute acid. The commercial concentrated acid usually has a spec, grav. varying from 1.834 to 1.836 at 15° C. (59° F.), correspond- ing to from 93 to 94 per cent, of absolute acid. Two strengths of sulphuric acid are officinal, an acid having a spec. grav. not less than 1.840 (1.836-1.840 Pharm. Germ.; 1.843 Brit. Pharm.), and containing not less than 96 per cent, of absolute sulphuric acid; and Acidum Sulphuricum Dilutum, spec. grav. about 1.067 (1.110-1.114 Pharm. Germ.; 1.094 Brit. Pharm.), containing 10 per cent, of absolute acid. Sulphuric acid has a strong attraction for water, absorbing it from the atmosphere, and withdrawing it or its elements from organic compounds immersed in, or mixed with, the acid; sul- phuric acid, therefore, when in contact with organic substances, or with air containing dust, gradually loses its colorless appear- ance, and becomes more or less brown, and rapidly chars and destroys most organic substances. Sulphuric acid is miscible with water, glycerin, alcohol, and other solvents, with evolution of heat, and produces, with most organic liquids, a more or less vehement decomposition ; in its relations to other compounds, it maintains the character of one of the strongest acids, its affinity for bases being so powerful as to withdraw them from most of their compounds, forming sulphates, which, with the exception of those of barium, strontium, calcium, and lead, are freely soluble in water, the latter three being very sparingly soluble, while barium sulphate is practically insoluble in both water and dilute acids. By the same powerful affinity, sulphuric acid, in its dilute condition, dissolves most of the metals (iron, zinc, magnesium, cobalt), with the evolution of hydrogen and formation of sulphate of the metal; when concentrated it does not act in the cold upon many of the metals, but, when heated, most of them (copper, mercury, silver, lead, tin, etc.) are attacked, with the evolution of sulphur dioxide, in consequence of the reduction of the acid by the liberated hydrogen at the high temperature. In consequence of its affinity for water, a piece of pine wood dipped into concentrated sulphuric acid becomes black from sepa- ration of carbon, and when a fragment of cane-sugar is placed in contact with the acid the latter will likewise assume a dark colora- tion, and upon heating develop the odor of sulphurous acid. When one drop of the acid is diluted with a test-tubeful of water, a white precipitate will be produced on the addition of a few drops of a solution of barium chloride. Examination: Fixed impurities are recognized by a residue after the complete evaporation of a small quantity of the acid in a platinum or porcelain capsule. Lead is indicated by a white turbidity taking place upon the 186 MANUAL OF CHEMICAL ANALYSIS careful admixture of one part of the acid with about four or five times its volume of alcohol. Another method of readily recognizing the presence of lead in sulphuric acid is, to about half fill a small conical cylinder with concentrated hydro- chloric acid, and then to place below the acid, by means of a pipette, a nearly equal volu me of the sulphuric acid, with care that the fluids do not mix (Fig. 79); an ensuing white tur- bidity at the j unction of the two fl uids would confirm the presence of lead. The presence of metallic impuri- ties in general may be detected, after the previous dilution of the acid with several times its volume of water, and warming it gently, by saturating with hydrogen sulphide. The liquid, after standing for several hours, is filtered from any precipitate which may have been formed, subsequentljr supersaturated with ammonia-water, ammonium sulphide added, and, when required, further examined by the methods de- scribed in the course of analytical investigation (pages 51 to 59). Arsenic maybe detected in the acid, previously diluted with about five times its volume of water, and gently warmed, by the production of a yellow precipitate upon saturation with hydrogen sulphide, as indicated in the preceding test. If specially sought for, it may, together with sulphurous acid, be readily detected by heating the diluted acid, in a test-tube, with a few fragments of pure zinc, and placing over the orifice of the tube a cap of bibulous paper moistened with a drop of solution of argentic nitrate (Fig. 80); the production of a black stain upon the paper will indicate either arseiiious or sulphurous acids. Nitric and nitrous acids may be detected by the addi- tion of a drop of indigo solution to a small portion of the acid, and gently warming, when decoloration of the liquid will ensue; or a crystal of ferrous sulphate is added to the acid, or a solution of the latter salt carefully poured upon it, without mixing, so as to form two dis- tinct layers (Fig. 81), when, in either case, a brown coloration of the crystal, or a brown zone at the point of contact of the two liquids, will indicate the above-mentioned impurities. By carefully mixing the concentrated acid with about half its Fig. 79. Fig. 80. ACID A 187 volume of a solution of 5 drops of pure aniline in 25 cubic cen- timeters of dilute sulphuric acid, so as to form at first two layers, the mixture will assume a rose-red coloration in the presence of nitric or nitrous acids. A special test for nitric acid consists in the production of a rose-red coloration on the addition of a few drops of an aqueous solution of brucine. Fig. 81. Hydrochloric acid will be detected in the acid, diluted with twenty times its volume of water, by the production of a white, curdy precipitate on the addition of solution of argentic nitrate. Estimation: Sulphuric acid may be most conveniently estimated volumet- rically by the process of neutralization. From 2 to 3 grams of the strong acid, or a corresponding quantity of dilute acid, is accurately weighed in a beaker, about 50 cubic centimeters of water, and a few drops of litmus solution added, and a normal solution of potassium or sodium hydrate (page 87) allowed to flow into the liquid from a burette until, with constant stirring, a per- manent blue tint is produced. Sulphuric acid being dibasic, 1 cubic centimeter of the normal alkali solution corresponds to 0.049 gram II2S04, which, multiplied by the number of cubic centimeters of normal alkali solution employed, will give the amount of absolute acid in the specimen under examination, and from which the percentage strength may be calculated. By deter- mining the spec. grav. of the acid, the correctness of the result may be verified by comparing it with the percentage strength of an acid of the same specific gravity, as indicated in the subjoined table, page 189. To neutralize 2.45 grams of the strong officinal acid, diluted 188 MANUAL OF CHEMICAL ANALYSIS. with about 10 volumes of water, not less than 48 cubic centimeters of normal solution of potassium or sodium hydrate should be required; and to neutralize 9.8 grams of the officinal diluted acid should require from 19.2 to 20 cubic centimeters of normal alkali. The gravimetric estimation of sulphuric acid is readily accom- plished, although less quickly than by the preceding method, by its conversion into barium sulphate. To a weighed quantity of the acid, largely diluted with water, a few drops of hydrochloric acid are added, the mixture heated to boiling, and subsequently a solution of barium chloride added until no further precipitate is produced. After standing for some hours, the precipitate is col- lected on a filter, thoroughly washed with hot water, dried, and finally ignited at a red heat. 100 parts of barium sulphate corre- spond to 42.06 parts of sulphuric acid, H2S04, or 34.33 parts of sulphuric anhydride, S03. Rales for the Dilution of Sulphuric Acid. If a strong acid a has to be diluted with water or with a weaker acid c, in order to obtain an acid of some special strength 5, the following rules are applicable: The difference in percentage strength is sought on the one hand between a and 5, and on the other between b and c, and a and c then mixed in the proportions represented by the difference in the respective numbers. It must be observed, however, that when the difference between a and b is greater than between b and c, less of a than of c must be taken in order to obtain b; and when the difference between a and b is less than between b and c, more of a than of c must be employed in order to obtain b; for example: I. Sulphuric acid containing 29 per cent, of absolute acid is to be mixed with water to form an acid containing 25 per cent, of absolute acid: a. b. c. 29 per cent. 25 per cent. 0 per cent. 4 25 Difference 25 parts of 29 per cent, acid are therefore to be mixed with 4 parts of water, or 100 grams of sulphuric acid = 29 grams II2S04. 16 “ “ water = 116 grams of sulphuric acid = 29 grams H2S04. or 100 “ “ “ “ = 25 “ II. Sulphuric acid containing 32 per cent, of absolute acid is to be mixed with an 8 per cent, acid to form an acid containing 14 per cent, of absolute acid : ACID A 189 a. b. c. 32 per cent. 14 per cent. 8 per cent. 18 6 (3) (1) Difference 1 part of 32 per cent, acid is therefore to be mixed with 3 parts of 8 per cent, acid, or 100 grams of sulphuric acid = 82 grams ILSO. 300 “ “ “ “ = 24 " “ “ 400 grams of sulphuric acid = 56 grams H S04 or 100 “ “ “ “ = 14 “ “ Table of the quantity by weight of Sulphuric Acid and the corresponding amount of Sulphuric Anhydride (SOa), contained in 100 parts by weight of Aqueous Sulphuric Acid of different specif c gravities ( Otto). Temperature 15° 0. (59° F.). Specific gravity. Per ct. of h2so4. Per cent, of S03. Specific gravity. Per ct. of h,so4. Per cent, of S03. Specific gravity. Per ct. of II„S04. Per cent, of S03. 1.8426 100 81.63 1.578 66 53.87 1.239 32 26.12 1.842 99 80.81 1.557 65 53 05 1.231 31 25.30 1.8406 98 80.00 1.545 64 52.24 1.223 30 24.49 1.840 97 79.18 1.534 63 51.42 1.215 29 23 67 1.8384 96 78.36 1.523 62 50.61 1.2066 28 22.85 1.8376 95 77.55 1.512 61 49.79 1.198 27 22.03 1.8356 94 76/(3 1.501 60 48.98 1.190 26 21.22 1.834 93 75.91 1.490 59 48.16 1.182 25 20.40 1.831 92 75.10 1.480 58 47.34 1.174 24 19.58 1.827 91 74.28 1.469 57 46.53 1.167 23 18.77 1.822 90 73.47 1.4586 56 45.71 1.159 22 17.95 1.816 89 72.65 1.448 55 44.89 1.1516 21 17.14 1.809 88 71.43 1.438 54 44.07 1.144 20 16.32 1.802 87 71.02 1.428 53 43.26 1.136 19 15.51 1.794 86 70.10 1.418 52 42.45 1.129 18 14.69 1.786 85 69.38 1.408 51 41.63 1.121 17 13.87 1.777 84 68.07 1.398 50 40.81 1.1136 16 13.06 1.767 83 67.75 1.3886 49 40.00 1.106 15 12.24 1.756 82 66.94 1.379 48 39.18 1.098 14 11.42 1.745 81 66.12 1.370 47 38.36 1.091 13 10.61 1.734 80 65.30 1.361 46 37.55 1.083 12 9.79 1.722 79 64.48 1.351 45 36.73 1.0756 11 8.98 1.710 78 63.67 1.342 44 35.82 1.068 10 8.16 1.698 77 62.85 1.333 43 35.15 1.061 9 7.34 1.686 76 62 04 1.324 42 34.28 1.0536 8 6.53 1.675 75 61.22 1.315 41 33.47 1.0464 7 5.71 1.663 74 60.40 1.306 40 32.65 1.039 6 4.89 1.651 73 59.59 1.2976 39 31.83 1.032 5 4.08 1.639 72 58.77 1.289 38 31.02 1.0256 4 3.26 1.627 71 57.95 1 281 37 30.20 1.019 3 2.445 1.615 70 57.14 1.272 36 29.38 1.013 2 1.63 1.604 69 56.32 1.264 35 28.58 1.0064 1 0.816 1.592 68 55.59 1.256 34 27.75 1.580 67 54.69 1.2476 33 26.94 190 MANUAL of chemical analysis. With the decrease and increase of temperature, the specific gravity of sulphuric acid suffers a corresponding increase or decrease, amounting for each degree of the centigrade thermometer in either direction : For acids of a specific gravity of 1.842 to those of 1.786 to about 0.0014 “ “ “ “ 1.777 “ 1.663 “ 0.0012 “ “ “ “ 1.651 “ 1.306 “ 0.001 “ “ “ “ 1.297 “ 1.215 “ 0.00075 “ “ “ “ 1.206 “ 1.144 “ 0.00045 “ “ “ “ 1.136 “ 1.C68 “ 0.00047 ACIDUM SULFHTJROSUM. Ger. Schweflige Saure ; Fr. Acide sulfureux; Sp. Acido sulfuroso. Sulphurous Acid. A colorless liquid, possessing the characteristic suffocating odor of burning sulphur. The most concentrated acid which can be obtained by saturating water with the gas at ordinary tempera- tures contains 9.54 per cent, of sulphur dioxide, and has a specific gravity of 1.046. The officinal acid is stated to have a specific gravity of 1.022 to 1.023 (1.04 Brit. Pharm. = 9.2 per cent S02), corresponding to about 5.7 per cent, of sulphur dioxide. It pos- sesses a very acid, sulphurous taste, and has a strongly acid reac- tion upon litmus, which it first reddens and afterwards bleaches. When heated to boiling, it loses sulphur dioxide, becoming finally completely volatilized; and when exposed to the light it becomes gradually decomposed with the formation of pentathionic acid, II2Sj06, and in contact with the air is readily oxidized to sulphuric acid. Sulphurous acid possesses a strongly reducing action, to which are due also its bleaching properties; it separates metallic gold, silver, and mercury from solutions of their salts, and liberates iodine from a solution of potassium iodate, which imparts a blue color to mucilage of starch. When hydrogen is generated by the action of dilute sulphuric acid upon a few fragments of pure metal- lic zinc, contained in a test-tube, and a few drops of sulphurous acid are added, the latter will become reduced to hydrogen sul- phide, and impart a black stain to a piece of bibulous paper moist- ened with a solution of plumbic acetate, and placed over the mouth of the tube. Examination: Sulphuric acid may be detected by a white precipitate, insoluble in hydrochloric acid, upon the addition of a solution of barium chloride. The amount of sulphuric acid present should not be sufficient to produce more than a very slight turbidity, when to 10 cubic centimeters of sulphurous acid 1 cubic centimeter of diluted hydrochloric acid is added, and subsequently 1 cubic cen- timeter of test-solution of barium chloride. ACIDA 191 Estimation: The strength of an aqueous solution of sulphurous acid may be approximately determined by ascertaining its specific gravity, and subsequent reference to the subjoined table, or, more accurately, by the following method of volumetric estimation: About 2 grams of the acid, diluted with 50 cubic centimeters of water, are placed in a flask, a little mucilage of starch added, and then a decinormal solution of iodine, the exact strength of which has been previously determined, page 93, allowed to flow into the liquid from a burette until, with constant stirring, a per- manent blue coloration is produced ;* the sulphurous acid be- comes thus oxidized to sulphuric acid, according to the equation: I2 + H2S03 + II20 = H2S04 + 2 HI. 254 (127) 82 (41) From the number of cubic centimeters of iodine solution employed, the amount of sulphur dioxide or of absolute sulphurous acid may be calculated; one cubic centimeter of the iodine solution, corrected if necessary by its proper factor, page 95, corresponding to 0.0032 gram of sulphur dioxide, S02, or 0.0041 gram of abso- lute sulphurous acid, H2S03. The IT. S. Pharmacopoeia directs that 1.28 grams of sulphurous acid, diluted with 20 volumes of water, and a little mucilage of starch added, should require the addition of at least 14 cubic cen- timeters of the volumetric solution of iodine before a permanent blue tint is developed, corresponding to at least 3.5 per cent, of sulphur dioxide. Table of the parts by weight of Sulphur Dioxide contained in 100 parts by weight of aqueous Sulphurous Acid, of different specific gravities (Anthon). Temperature 15° C. (59° F.). Specific gravity. Per cent, of S02. Specific gravity. Per cent of S02. 1.046 9.54 1.020 4.77 1.036 8.59 1.016 3.82 1.031 7.63 1.013 2.86 1.027 6.68 1.009 1.90 1.023 5.72 1.005 0.95 * On account of the volatility of sulphurous acid, it is important that such estimations be performed as quickly as possible, in order to prevent loss by evaporation. 192 MANUAL OF CHEMICAL ANALYSIS. ACIDUM TANNICUM. Ger. Gerbsaure ; Fr. Acide tannique ; Sp. Acido tanico. Tannic Acid. Tannin. ChH10O9 = C0H8(OH)2CO-OH ) C6H2(OH),CO f O; 822. Amorphous, friable, porous, and inodorous masses, or thin shin- ing scales, of a pale greenish-yellow color, and feeble, mild odor* (mostly combined with a faint odor of ether); when heated upon platinum-foil, tannic acid fuses, swells up, and burns away without residue. Tannic acid is soluble in 6 parts of water or glycerin, in 0.6 part of alcohol, and in less than its own weight of diluted alcohol, and very freely soluble in boiling water and in boiling alcohol; it is but sparingly soluble in absolute alcohol and in commercial ether, and almost insoluble in absolute ether, chloroform, carbon bisulphide, benzol, benzin, and the fixed and volatile oils. Its aqueous solution reddens litmus-paper, and has an astringent taste, without bitterness; it becomes turbid when boiled, and gradually dark-colored and mouldy, when exposed to the air; it suffers pre- cipitation by the alkaline salts, and by the mineral acids, and forms soluble compounds with the alkaline hydrates, sparingly soluble ones with the earthy oxides, and more or less insoluble ones with most of the metallic oxides; its solution coagulates solutions of gelatin, albumen, and starch (distinction from gallic acid), and affords white precipitates, soluble in acetic acid, with the alka- loids ;f it produces no reaction with ferrous salts, if completely free from ferric salts, but it gives a bluish-black precipitate with the latter, which is soluble in oxalic and mineral acids. When solution of tannic acid is dropped into lime-water, it produces a white turbidity, which soon becomes gray and dingy green, and passes through various shades to a dark purple-brown color. If to a very dilute aqueous solution of tannic acid a small quan- tity of iodine-water be added, a colorless solution will be obtained, which, on the addition of a very little ammonia-water, assumes a transient, fine red coloration ; if the iodine-water be added in such an amount as of itself to impart a slight reddish tint to the liquid, and lime-water, instead of ammonia, be then added, a blue colora- tion will be produced. Examination: The absence of admixtures of resinous sulstances, yum, dextrin, and of suyar, may be ascertained by the property of the acid to yield a clear or nearly clear solution with about four or five parts of warm water, which should remain so when tested in two por- tions, the one by addition of twice its volume of strong alcohol, * The color and odor are due to traces of a greenish resin, f Morphine is precipitated only from very concentrated solutions, and the precipitate is readily dissolved by a slight excess of tannic acid. ACID A 193 the other by dilution with water; if any such adulterations be present, they may be separated and recognized by making two solutions of the acid, one in strong alcohol, when gum, sugar, and dextrin will remain behind, and another one in boiling water, when resinous substances will remain undissolved or be separated on cooling. Estimation: In consequence of the variable nature of tannic matters as de- rived from different sources, and the impurities with which they are frequently accompanied, their exact quantitative estimation in technical products, vegetable extracts, etc., is often attended with considerable difficulty. Of the various methods proposed, two of the less complicated will here be given, which, however, in most instances afford sufficiently accurate results. I. The substance to be examined is extracted with strong alcohol, the alcoholic liquid evaporated at a gentle heat to the consistence of a soft extract, and the residue taken up with just sufficient water to insure the complete solution of the tannic mat- ter. To the clear aqueous solution a solution of neutral plumbic acetate is then added until a precipitate ceases to be produced, the precipitate collected upon a tared filter, washed three or four times with small portions of water, dried at 100° C. (212° F.) until of constant weight, and its weight finally determined. The precipi- tate is then removed from the filter, the latter, together with a little ammonium nitrate, brought into a porcelain crucible and ignited, and afterward the precipitate added, and the whole ignited at a strong heat until the weight remains constant. The wreight of the ignited plumbic oxide, subtracted from the previously determined weight of the lead precipitate, will represent the amount of tannic acid, together with other organic acids or bitter principles precipitable by plumbic acetate, which may be contained in the substance under examination. II. This method depends upon the precipitation of the tannic acid as zinc tannate, and the estimation of the latter by means of a solution of potassium permanganate. A solution of zinc acetate in an excess of ammonia water yields with tannic acid a precipi- tate of zinc tannate, insoluble in an excess of the reagent, in wrater or ammonia-water, but is not precipitated by alcohol, glycerin, potassium or calcium tartrate, albumen, or by ferric and ferrous salts of the organic acids; with gallic acid and aluminium salts it yields a precipitate, which, however, is soluble in an excess of the reagent and in ammonia-water. The solutions required in this process of estimation are : 1. A solution of zinc acetate, prepared by dissolving 10 grams of crys- tallized zinc acetate in 200 cubic centimeters of water, and the subsequent addition of 130 grams of ammonia-water, spec. grav. 0.960. 2. Diluted sulphuric acid, prepared by mixing 1 part of sulphuric acid, spec. grav. 1.81, with 5 parts of water; and 3. A 194 MANUAL OF CHEMICAL ANALYSIS. solution of 1.333 grams of crystallized potassium permanganate in 1 liter of water. In order to determine the oxidizing power of the permanganate solution, a solution of pure tannic acid of known strength is prepared ; for instance, 1 gram of pure tannin dis- solved in 1 liter of water. If it be found, for example, that 20 cubic centimeters of this tannin solution require the addition of 10 cubic centimeters of permanganate solution in order to pro- duce a permanent pink tint, then 1 cubic centimeter of the per- manganate solution corresponds to 0.002 gram of pure tannin. The estimation is then performed as follows: To about 50 cubic centimeters of the liquid to be examined, a slight excess of the solution of zinc acetate above that required to completely precipi- tate the tannin is added, the mixture heated to boiling, subse- quently evaporated to about one-third of its volume, and allowed to cool. The precipitate of zinc tannate is then collected on a filter, washed with hot water, subsequently dissolved in diluted sulphuric acid, and the solution titrated with potassium perman- ganate until a permanent pink tint is produced. If, for example, 15 cubic centimeters of the potassium permanganate solution are employed, and, as by the above determination, 1 cubic centimeter of permanganate solution corresponds to 0.002 gram of tannin, consequently 15 cubic centimeters of permanganate solution cor- respond to 0.002 x 15 = 0.03 gram of tannin. As this amount is contained in 50 cubic centimeters of the liquid under examination, 100 cubic centimeters will contain 0.06 gram, or 0.06 per cent, of pure tannic acid. Table of the amount by weight of pure Tannic Acid contained in 100 parts by iveight of its aqueous solutions of different specific gravit es (Hammer). Temperature 15° C. (59° F.). Specific graviiy. Per cent, of tannic acid. Specific gravity. Per cent, of tannic acid. Specific gravity. Per cent, of tannic acid. Specific gravity. Per cent, of taunic acid. 1.0010 0.25 1.0211 5.25 1.0416 10.25 1.0625 15.25 1.0020 0.50 1.0222 5.50 1.0427 10.50 1.0635 15.50 1.0030 0.75 1.0232 5.75 1.0437 10.75 1.0646 15.75 1.0040 1.00 1.0242 6.00 1.0447 11.00 1.0656 16.00 1.0050 1.25 1.0252 6.25 1.0458 11.25 1.0666 16.25 1.0060 1.50 1.0263 6.50 1.0468 11.50 1.0677 16.50 1.0070 1.75 1.0273 6.75 1.0479 11.75 1.0688 16.75 1.0080 2.00 1.0283 7.00 1.0489 12.00 1.0698 17.00 1.(090 2.25 1.0293 7.25 1.0499 12.25 1.0709 17.25 1.0100 2.50 1.0304 7.50 1.0510 12.50 1.0719 17.50 1.0110 2.75 1.0314 7.75 1.0520 12.75 1.0730 17.75 1.0120 3.00 1.0324 8.00 1.0530 13.00 1.0740 18.00 1.0130 3.25 1.0334 8.25 1.0541 13.25 1.0751 18.25 1.0140 3.50 1.0345 8.50 1.0551 13.50 1.0761 18.50 1.0150 3.75 1.0355 8.75 1.0562 13.75 1.0772 18.75 1.0160 4.00 1.0365 9.00 1.0572 14.00 1.0782 19.00 1.0171 4.25 1.0375 9.25 1.0583 14.25 1.0792 19.25 1.0181 4.50 1.0386 9.50 1.0593 14.50 1.0803 19.50 1.0191 4.75 1.0396 9.75 1.0604 14.75 1.0814 19.75 1.0201 5.00 1.0406 10.00 1.0614 15.00 1.0824 20.00 AC IDA 195 ACIDTJM TARTARICUM. Tartaric Acid. Ger. Weinsaure ; Fr. Acide tartarique ; Sp. Acido tartarico. CH(OH)-CO-OH I ; CH(OH)-CO-OH C4H6°6 = 150. Colorless, transparent, monoclinic prisms (Fig. 82), permanent in the air; they contain no water of crystallization, and, when cautiously heated in a glass tube, fuse at 185° C. (275° F.) to a transparent, vitreous, very deliquescent mass of metatartaric acid, C4II606; when strongly heated, with exposure to the air, they are decomposed with the evolution of inflammable vapors of a peculiar odor, resembling that of burnt sugar, and with the separation of carbon, and are finally wholly dissipated. Tartaric acid is soluble in 0.7 part of cold, and in 0.5 part of boiling, water; in 2.5 parts of cold, and in 0.2 part of boiling, alcohol; in 36 parts of absolute alcohol, in 23 parts of commercial ether, -or 250 parts of absolute ether; and is nearly insoluble in chloroform, benzol, and benzin. Its solutions possess a strongly acid taste and reaction, and, when dropped into solutions of neutral potassium salts, give rise to the formation of a white granular precipitate, at once in concentrated solutions, and after a time in diluted ones. This reaction, how- ever, does not take place in solutions containing free mineral acids or acid salts thereof. When solution of tartaric acid is dropped into lime-water, so that the alkaline reaction predomi- nates, a white turbidity occurs (distinction from citric acid), which disappears again upon the addition of solution of ammonium chlo- ride (distinction from racemic acid), and also upon the addition of acetic acid (distinction from oxalic acid); solution of calcium sul- phate remains unchanged upon the addition of tartaric acid (addi- tional distinction from oxalic and racemic acids). Crystals of tartaric acid, when immersed in concentrated sul- phuric acid, dissolve gradually without coloration, unless warmed, when they become black, and, on more strongly heating, with the development of carbon monoxide, carbon dioxide, and sulphurous acid gas. Examination: Salts.—An admixture of salts is recognized by the addition of an equal volume of alcohol to a cold saturated aqueous solution of the acid, or by dissolving the powdered acid in 6 parts of strong Fig. 82. 196 MANUAL OF CHEMICAL ANALYSIS. alcohol; a complete and permanent solution must ensue in either case. Sulphuric acid or sulphates may be detected in the diluted solu- tion, to which a little hydrochloric acid has been added, by a white turbidity with barium nitrate. If 10 cubic centimeters of a strong solution of tartaric acid be employed for the test, no pre- cipitate should be produced within five minutes upon the subse- quent addition of 1 cubic centimeter of test-solution of barium chloride, and an excess of hydrochloric acid. Chlorides may be detected in the diluted solution, by a white precipitate, insoluble in nitric acid, on the addition of a solution of argentic nitrate. Oxalic acid or oxalates may be detected in the concentrated aqueous solution of the acid, by a white precipitate when tested with solution of calcium sulphate. Calcium salts may be detected in the diluted solution, pre- viously nearly neutralized with ammonia-water, so that the acid reaction still predominates, by a white precipitate on the addition of ammonium oxalate. Metallic impurities (copper or lead) are detected by a brown or blackish coloration or precipitate, when a concentrated aqueous solution of the acid is saturated with hydrogen sulphide; after filtering, if necessary, and subsequent super-saturation with am- monia-water, an ensuing dark coloration would indicate iron. Estimation: One hundred parts of tartaric acid require for exact neutraliza- tion 92.2 parts of anhydrous potassium carbonate, 138.33 parts of crystallized potassium bicarbonate, 190.6fi parts of crystallized sodium carbonate, 112 parts of sodium bicarbonate, and 63.83 parts of magnesium carbonate. The estimation of tartaric acid may also be conveniently ac- complished volumetrically with sufficient accuracy, since, unlike citric acid, its point of neutralization as indicated by means of litmus may be distinctly observed. About 3 grams of the crystallized acid, accurately weighed, are dissolved in about 50 cubic centimeters of water, a few drops of litmus solution added, and a normal solution of potassium' or sodium hydrate (page 87) allowed to flow into the liquid from a burette until, with constant stirring, a distinct blue tint is pro- duced. Tartaric acid being disbasic, one cubic centimeter of normal alkali corresponds to 0.075 gram of the crystallized acid, and from the number of cubic centimeters of alkali solution em- ployed. the purity or percentage strength of the acid may be readily calculated. If 8.75 grams of acid, and a strictly normal solution of alkali are employed, the number of cubic centimeters of the latter required for neutralization, when multiplied by 2, will represent-at once the percentage purity of the acid. Another method of estimation consists in adding to a solution ACIDA 197 of 1 part of tartaric acid in 8 parts of cold water, a solution of 1 part of potassium acetate in 3 parts of cold water, and subse quently adding a volume of alcohol equal to that of the whole mixture; after being allowed to stand for 2 hours, the white, crystalline precipitate of acid potassium tartrate is collected upon a tared filter, well washed with diluted alcohol, and dried at 100° C. (212° F.), when it should weigh between 1.25 and 1.26 parts. Table of the parts by weight of crystallized Tartaric Acid, contained in 100 parts by weight of aqueous solutions of the acid of different specific gravities (Gerlach). Temperature 15° C. (59° F.). Specific gravity. Per cent, of tartaric acid. Specific gravity. Per cent, of tartaric acid. Specific gravity. ■ Per cent of tartaric acid. 1.0045 1 1.09693 20 1.2019 39 1.0090 2 1.1020 21 1.20785 40 1.0136 3 1.1072 22 1.2138 41 1.0179 4 1.1124 23 1.2198 42 1.0224 5 1.1175 24 1.2259 43 1.0273 6 1.1227 25 1.2317 44 1.0322 7 1.1282 26 1.2377 45 1.0371 8 1.1338 27 1.2441 46 1.0420 9 1.1393 28 1.2504 47 1.04692 10 1.1449 29 1.2568 48 1.0517 11 1.15047 30 1.2632 49 1.0565 12 1.1560 31 . 1.26962 50 1.0613 13 1.1615 32 1.2762 51 1.0661 14 1.1670 33 1.2828 52 1.0709 15 1.1726 34 1.2894 53 1.0761 16 1.1781 35 1.2961 54 1.0813 17 1.1840 36 1.3037 55 1.0865 18 1.1900 37 1.3093 56 1.0917 19 1.1959 38 1.3169 57 ACIDUM VALERIANICUM. Valerianic Acid. Isopropyl-acetic Acid. Ger. Valeriansaure, Baldriansaure ; Fr. Acide valerianique; Sp. Acido valerianico. C5H1002 = >CH-CH,-CO-OH ;* 102. Pure valerianic acid forms a thin, colorless, or nearly colorless liquid, having the persistent odor of valerian-root, and a pungent, acid taste; it reddens litmus, bleaches the skin, and burns when * Of the acids having the empirical formula C-,H10O2, four modifications are theoretically possible, all of which are at present known : (1) Normal valerianic acid, (2) The medicinal 198 MANUAL OF CTHEMICAL ANALYSIS. inflamed with a bright, smoky light. In contact with water, it absorbs about 20 per cent, of its weight without losing its oily con- sistence, and is itself soluble in 25 parts of water at 15° 0. (59° F.); it is miscible with ammonia-water, alcohol, and ether, in all pro- portions. Its spec. gray, is 0.934 at 15° C. (59° F.), and it boils at 175° 0. (347° F.). The commercial acid is generally the hydrate C5HI0O2 + H20, formed as above mentioned from the absolute acid by the absorption of about 20 per cent, of its weight of water, and, with reference to the old notation, was formerly known as the trihydrated acid, C10HQO3.3HO; it has the specific gravity 0.945, boils at 165° C. (329° F.), and may be also distin- guished from the absolute acid by its limited solubility in carbon bisulphide. When pure concentrated valerianic acid is added to an excess of mercuric oxide, a fine red solution of basic, uncrys- tallizable valerianate is obtained; the same coloration is produced by a less concentrated acid on warming the solution, a consider- able excess of the mercuric oxide being always maintained. Examination: Inorganic salts (valerianates) may be detected by a non-volatile residue on the evaporation of a small quantity of the acid in a small porcelain capsule. Foreign fatty acids will be indicated by a higher specific gravity of the acid, and may also be recognized as follows: One gram of the acid is weighed in a tared flask, and water, of a temperature of from 12 to 15° C. (53.6 to 59° F.), is carefully added, with constant agitation, until the acid is just dissolved. The flask is weighed again, and the quantity of water required for solution must be not less than twenty-five times the weight of the acid; in this instance, not less than twenty-five grams. If the acid dis- solves in less water, it is not pure, containing admixtures (alcohol, acetic acid, and butyric acid), which by their greater solubility increase that of the valerianic acid. On the other hand, the quan- tity of water required for solution must not exceed thirty times (30 grams) the weight of the valerianic acid, in which case it would contain less soluble or insoluble admixtures (caproic and similar monatomic acids, valeric aldehyde, etc.). The presence of valeric aldehyde, as also of amylic alcohol and amyl valerianate, ggAcH-OH.-CO-OH. acid, or isopropyl-acetic acid, CH:i .CH, >C<" ; ch (3) Trimetliyl-acetic CH3 i \H5CH3 CH CO-OH. acid, and (4) Etliyl-methyl-acetic acid, These acids, however, with the exception of the second or medicinal acid, are principally of theoretical interest, being formed for the most part by difficult synthetical methods, and differ materially in their physical and chemical properties. ACID A 199 may likewise be detected by neutralizing the acid with ammonia- water, when they will either separate as an oily layer or impart a turbidity to the liquid. If the preceding tests leave doubt as to the purity of the acid, or if a more conclusive examination be required, five grams of the acid are weighed in a beaker, and mixed with about ten grams of hot water; then from a burette, or a graduated pipette (Fig. 83), a solution of potassium carbonate, of 1.289 spec, grav. (containing 29 per cent, of an- hydrous carbonate), is added drop by drop, until the acid is exactly neu- tralized. The quantity by weight of the solution of potassium carbonate used must not exceed twice the quan- tity of the acid ; if a greater quantity be required, the presence of butyric, acetic, and similar homologous acids, is evident. When, in this test, oily drops are separated upon the surface of the liquid, the admixture of some neutral oily compound is indicated. Acetic acid may be detected by care- fully neutralizing a small portion of the acid with ammonia-water, and subsequently adding a dilute solution of ferric chloride until no further precipitate is produced; after the subsidence of the amorphous reddish- brown precipitate of ferric valerianate, the supernatant liquid should appear colorless or nearly so; a bright red color will indi- cate the presence of acetic acid. Mineral acids may be detected in the aqueous solution of the valerianic acid by adding a few drops of nitric acid, and subse- quently testing portions of it with barium nitrate for sulphuric acid, and with argentic nitrate for hydrochloric acid. Fig. 83. 200 MANUAL OF CHEMICAL ANALYSIS. ACONITINA. ACONITINUM. Aconitine. Aconitia. Ger. Aconitin ; Fr. Aconitine ; Sp. Aconitina. White, amorphous pulverulent grains, or a white or yellowish- white powder, which, with some difficulty, may be obtained from its solutions in a crystalline form. It melts at 120° C. (248° F.), and at a higher temperature is decomposed, with the evolution of ammonia; when strongly heated on platinum-foil, it burns with a smoky flame, and is finally completely dissipated. Aconitine is soluble in 150 parts of cold water; with hot .water it becomes soft and resin-like, and dissolves gradually in the pro- portion of 1 part of aconitine to 50 parts of boiling water, most of the alkaloid being again separated on cooling; it dissolves freely in alcohol, ether, chloroform, amylic alcohol, beuzin, warm benzol, and in dilute acids. The aqueous solution possesses a feeble alkaline reaction, and an acrid and persistent bitter taste; the latter being dependent, however, upon the presence of another alkaloid, Pier aconitine, having the formula C3IH4JNO,0. The solutions of aconitine in water yield with phospho-molybdic acid a yellowish-gray precipitate, becoming blue on the addition of ammonia; with tannic acid, potassio-mercuric iodide, and potas- sio-cadmic iodide, white, amorphous precipitates; with potassio- bismuthie iodide an orange-red precipitate, and with iodine in potassium iodide a reddish-brown precipitate, but are not precipi- tated by platinic or mercuric chlorides, or picric acid. The solu- tions of the salts of aconitine show the same behavior towards reagents, but are precipitated by picric acid, as also by solutions of sodium hydrate, sodium carbonate, and ammonia-water. Aconitine dissolves in nitric acid with but a slight yellowish coloration; with concentrated sulphuric acid, it forms a coherent mass, which dissolves upon agitation, with a bright yellow color, and, at ordinary temperatures, gradually passes through brown or reddish-brown to violet-red. When dissolved in dilute phosphoric acid, and the solution allowed to evaporate slowly in a porcelain capsule on the water-bath, a fine violet color is also produced. When aconitine is boiled with inorganic acids or alkalies, it is resolved into benzoic acid, and an uncrystallizable base, aconine: C33H43N012; 645. C33H4,N012 + H20 = C7H602 + C2flH39NOn An alkaloid formerly occasionally met with in commerce under the name of Morson's, or English aconitine, which differs in its physical, chemical, and therapeutical properties from the above Aconitine. Benzoic acid. Aconine. J1THER. 201 described, is now recognized as consisting wholly or in part of a distinct body, and has received the name of Pseudaconitine or Nepaline, C3fiII49N012. It is derived from the Indian or Nepal aconite, Aconitum ferox Wallich, and is distinguished from aco- nitine by its elementary composition, its higher melting-point, 185-200° C. (365-392° F.), and much more sparing solubility in water, alcohol, ether, and chloroform, requiring about 250 parts of the latter for solution, while ordinary aconitine is soluble in 3 parts of chloroform. It crystallizes very readily from its solutions in the form of colorless, rhombic octahedra, and yields some well crystallizable salts, but does not produce the above described reactions of ordinary aconitine with sulphuric and phos- phoric acids, which, however, do also not pertain to true, crystal- lized aconitine. When pseudaconitine or nepaline is boiled with inorganic acids or alkalies, it appears to be first converted by dehydration into apopseuda coni tine, C,6H47NOn, which latter is afterwards split into veratric acid and apopseudaconine: C36H49N012 = C8H7(OH)2CO-OH + c27h39no8 Pseudaconitine. Veratric acid. Apopseudaconine. Commercial aconitine appears of itself not to be a definite sub- stance, but to consist of a mixture of true crystallizable aconitine, together with pseudaconitine, picraconitine, and their various derivatives, aconine, pseudaconine, and possibly other amorphous bases. For the isolation of aconitine from complex organic mixtures, or its separation and discrimination from other alkaloids, see also pages 108 and 109. Ether. Ethylic Ether. Ethyl Oxide. Ger. Aether; Fr. Ether ; Sp. Eter sulfurico. JETHER. C4H10O = (C2Hs)20; 74. A colorless, light, limpid, and highly refractive liquid, of a characteristic fragrant odor, very volatile and inflammable; it does not redden litmus, but gradually becomes slightly acid by the absorption of oxygen and the formation of acetic acid, from contact with the air in imperfectly stoppered bottles. When pure, its spec, grav., at 15.5° C. (60° F.), is about 0.720 ; it boils at 34.9° C. (94.8° F.) under a pressure of 760 mm., and does not solidify by exposure to the most intense cold. The United States Pharmacopoeia provides two strengths of 202 MANUAL OF CHEMICAL ANALYSIS. ether, one of the spec. grav. 0.750, at 15° C. (59° F.), contain- ing about 74 per cent., and tether fortior, of a spec. grav. not exceeding 0.725 at 15° C. (59° F.), or 0.716 at 25° C. (77° F.), and containing about 94 per cent, of ethylic ether. Ether is miscible, in all proportions, with alcohol, carbon bisul- phide, chloroform, benzol, benzin, and the fixed and volatile oils; pure ether dissolves but one thousandth part of its weight of water, but is soluble in 20 parts by weight of water at 12° C. (53.6° F.). From its solution in ether, the water can again be almost wholly abstracted by contact with anhydrous potassium carbonate, provided that the ether be pure and free from alcohol. When completely free from alcohol and water, ether has no action on dry tannic acid, which deliquesces to a thick, syrupy fluid in aether fortior. Ether dissolves sulphur and phosphorus sparingly, but bro- mine, iodine, caoutchouc, essential oils, and most of the fatty and resinous substances, freely; it is also a solvent for a number of alkaloids, and for some metallic salts, e.y., mercuric, auric, platinic, and ferric chlorides, etc. Examination: Alcohol and Water.—Shaken with an equal bulk of water, in a small graduated cylinder (Fig. 84), officinal ether should not lose more than from one-fifth to one-fourth, and tether fortior not more than from one-tenth to one-eighth, of its volume; otherwise an excess of one or the other of the above is contained in the ether, which fact will also be indicated by a greater specific gravity of the ether than that above stated. A still more accurate result of this test is obtained when pure glycerin is employed instead of water, whereby both water and alcohol are at the same time abstracted ; the latter may then be recognized by sub- sequent distillation from the glycerin, and the addi- tion of a few drops of an aqueous solution of potassium chromate and sulphuric acid to the distillate, when the green color of chromic oxide will soon appear. In the application of the preceding test, the U. S. Pharmacopoeia requires that 10 cubic centimeters of ether, upon agitation with an equal volume of glycerin, should not be reduced to less than 7.5 cubic centimeters; and that when 10 cubic centi- meters of aether fortior are agitated with an equal volume of glycerin, the ether layer, when fully separated, should measure not less than 8.6 cubic centimeters. The presence of water in ether may also be detected by the appearance of a blue coloration on the addition of a little anhy- drous cupric sulphate, or by forming a turbid solution when the ether is mixed with an equal volume of carbon bisulphide. Fig. 84. jETHER 203 Acids.— Neutral blue litmus-paper, when previously moistened with water and immersed in both the ethereal and aqueous layers in the cylinder, should remain unaltered, as also when a small quantity of the ether is evaporated in a porcelain capsule until reduced in volume to a few drops, and then tested with litmus- paper; a slight acid reaction would indicate acetic acid, and, in crude ether, possibly sulphurous or sulphuric acid; the acid re- action may also be caused by traces of ethyl-sulphuric acid, which, together with other compound ethylic or amylic ethers, or alcohols, are also indicated when a small portion of the ether is allowed to evaporate spontaneously in a shallow porcelain capsule; when the ether has entirely evaporated, the inner surface of the capsule should be covered with a deposit of moisture, without taste or smell, and without any oily appearance. Table of the quantity by weight of pure Ethylic Ether contained in 100 parts by weight of Ether of different, specific gravities. Temperature 17.5° C. (63.5° F.). Specific gravity. Per ceat. of ethylic ether. Specific gravity. Per cent, of ethylic ether. Specific gravity. Per cent, of ethylic ether. Specific gravity. Per cent, of ethylic ether. 0.7185 100 0.7310 87 0.7456 74 0.7614 61 0.7198 99 0.7320 86 0.7468 73 0.7627 60 0.720(5 98 0.7331 85 0.7480 72 0.7640 59 0.7215 97 0.7342 84 0.7492 71 0.7653 51 0.7224 96 0.7353 83 0.7504 70 0.7666 57 0.7238 95 0.7364 82 0.7516 69 0.7680 56 0.7242 94 0.7375 81 0.7528 68 0.7693 55 0.7251 93 0.7386 80 0.7540 67 0.7707 54 0.7260 92 0.7397 79 0.7552 66 0.7721 53 0.7270 91 0.7408 78 0.7564 65 0.7735 52 0.7280 90 0.7420 77 0.7576 64 0.7750 51 0.7290 89 0.7432 76 0.7588 63 0.7764 50 0.7800 88 0.7444 75 0.7601 62 0.7778 49 With the decrease and increase of temperature, the specific gravity of ether suffers a corresponding increase or decrease, amounting for each degree of the centigrade thermometer in either direction— For ether of a specific gravity of 0.7198 to that of 0.7831, about 0.0013 “ “ “ “ 0.7342 “ 0.7504, “ 0.0011 “ “ “ “ 0.7516 “ 0.7627, “ 0.0009 “ “ “ “ 0.7640 “ 0.7764, “ 0.0008 For instance: An ether of 0.7206 spec. grav. at 17.5° C.. containing 98 per cent, ethyl oxide, will have, at 20° C., a spec. grav. of 0.7206— (0.0018 X 2.5) = 0.71735, and at 15° C., a spec. grav. of 0.7206+ (0.0013 X 2.5) =0.72385. 204 MANUAL OF CHEMICAL ANALYSIS. iETHER ACETICUS. Ger. Essigather ; Fr. Etlier acetique ; Sp. Eter acetico. Acetic Etlier. Ethyl Acetate. C4IIR02 = C2H30-0-C2Hs; 88. A colorless, light, limpid liquid, of an agreeable, ethereal, and fruity odor and taste; very volatile and combustible. When perfectly pure, its specific gravity is 0.898 at 15° C. (59° F.) and its boiling point 74.3° C. (165.7° F.), but as the removal of the last traces of alcohol is effected with great difficulty, its specific gravity usually varies from 0.900 to 0.904 at 15° C. (59° F.), and its boiling-point from 74 to 76° C. (165.2 to 168.8° F.). Acetic ether is miscible in all proportions with ether, alcohol, chloroform, carbon bisulphide, and benzol, and soluble in approximately 17 parts of water. It absorbs oxygen from the air, especially if it contains some water, forming acetic acid ; both the water and the acid can be removed from the ether by shaking it with exsiccated potassium carbonate, which will become more or less liquefied when these fluids are present. Examination: Its aqueous solution should afford no precipitate with a solution of barium chloride (sulphuric acid); and when a portion of the ether is allowed to evaporate in a porcelain capsule, it should leave no permanent residue {sodium or magnesium acetates). Alcohol.—When shaken with an equal volume of water in a graduated glass cylinder (Fig. 84, page 202), the ether, after sub- siding, should not have decreased in volume more than one-tenth to one-eighth ; when pure glycerine is employed instead of water, the volume of- both liquids should remain nearly unaltered. Alcohol and water are also indicated in connection with the pre- ceding test by a lower or higher specific gravity of the ether than that above mentioned. As acetic ether may be mixed in such proportions with alcohol and ether that the presence of these admixtures is not readily detected on the one hand by the deter- mination of the specific gravity alone, or on the other hand, by th.e test with absorption by water, it is necessary in its examina- tion to apply successively both of the above mentioned tests, by which means the admixture may be readily detected. Acids.—Neutral blue litmus-paper, when previously moistened with water, and immersed in both the ethereal and aqueous layers in the cylinder, should remain unaltered, as also when a portion of the ether is reduced to a small volume by evaporation in a porcelain capsule, and then tested with litmus-paper. Estimation of the Ethyl Acetate contained in Acetic Ether: The quantitative estimation of acetic ether is accurately and most conveniently accomplished volumetrically, by a process which de- iETHER ACETICUS. 205 pends upon its previous decomposition into alcohol and the acetate of an alkaline base; the amount of alkali required to effect the decomposition of a known and weighed amount of the ether being subsequently determined by the estimation of the excess of alkali employed with a standard acid. About 3 grams of acetic ether are accurately weighed in a bot- tle provided with a closely fitting glass stopper, and having a capacity of at least 200 cubic centimeters; 100 cubic centimeters of a decinormal solution of crystallized barium hydrate (contain- ing 15.75 grams Ba(OH)2 + 8II20 in a liter) are then added, the whole well mixed, and, having fastened the stopper securely by means of twine, the mixture is heated upon the water-bath for about two hours. The decomposition of the ether which is thus effected is expressed by the equation: 2C2H,0,(C,H,) + = 2C,Ha0 + BaCO^O^. Ethyl acetate. Barium hydrate. Alcohol. Barium acetate The bottle and its contents are finally allowed to cool, then opened and the liquid tested with curcuma paper, which should indicate by its brown coloration a decided alkaline reaction, while the odor of the acetic ether must at the same time have com- pletely disappeared. The contents of the flask are then trans- ferred to a beaker, the flask subsequently well rinsed with several small portions of water, and, after the addition of a few drops of litmus solution, a decinormal solution of oxalic acid (containing 0.3 grams C2H204 4- 2H20 in a liter) is allowed to flow into the liquid from a burette until, with constant stirring, a permanent red coloration appears, or preferably until a drop of the solution brought upon curcuma paper no longer produces a brown colora- tion. The number of cubic centimeters of oxalic acid solution employed for neutralization, when subtracted from that of the barium hydrate solution originally employed (100), will represent the number of cubic centimeters of barium hydrate solution re- quired for the decomposition of the ether, and therefrom the amount of ethyl acetate contained in the specimen under exami- nation or its percentage strength may be subsequently readily calculated: one cubic centimeter of decinormal barium hydrate solution corresponding to 0.008b gram of ethyl acetate. 206 MANUAL OF CHEMICAL ANALYSIS. ALCOHOL. SPIRITUS RECTIFICATUS. Ger. Spiritus, Weingeist ; Fr. Alcool; Sp. Alcohol. Ethyl Alcohol. C2H60 = C2H4-OH ; 46. A colorless, limpid, neutral liquid, inflammable, and burning with a pale blue flame, without smoke; its spec.grav. is 0,795 at 15° C. (59° F.); its boiling-point at 78.4:° C. (178.1° F.) ;* it is miscible in all proportions with most liquid bodies, but not with the fatty oils, with the exception of ricinus or castor oil, and, next to water, is the most extensive and important solvent, dis- solving most of the organic acids and resins, alkaloids, and many other bodies which are sparingly soluble in water. It replaces water in some organic compounds (chloral alcoholate, C2IIC130 4- C2IIftO), and may be substituted for the water of crystallization in some inorganic salts; e. g., CaCl2 4- 3C2IIftO, ZnCl2 4- 2C2H„0, Mg(N03)24- 6C2I160, PtCl44-2C2HI?0; all of which latter, how- ever, are decomposed by water with the liberation of the alcohol, and the absorption of their normal equivalent of water. Anhydrous alcohol has a great attraction for water, absorbing its vapor from the atmosphere, and abstracting the moisture from organic substances immersed in it. In the act of dilution, a con- traction of volume and an increase of the temperature of the mixture take place. When 55 volumes of absolute alcohol are mixed with 45 volumes of water, the mixture, after cooling, will occupy only 96.2 volumes, having therefore suffered a con- traction of 3.8 per cent.; and, vice versa, an expansion of volume takes place when diluted alcohol is mixed with water: e. g., when 100 volumes of alcohol, of a spec. grav. of 0.966, containing 29 per cent., by volume, of absolute alcohol, are mixed with 50 volumes of water, 153 volumes will be obtained. The percentage of absolute alcohol in its aqueous dilutions can be determined approximately, and with sufficient accuracy for any practical purpose, by ascertaining its specific gravity at a known temperature. The specific gravity of any sample of alcohol es- tablished will, by the aid of the following table, at once indicate the percentage of absolute alcohol: * The officinal alcohol has a spec. grav. of 0.820 at 15.6° C. (60° F.), or 0.812 at 25° C. (77° F.), and contains 94 per cent, by volume or 91 per cent, by weight of absolute alcohol; the diluted alcohol (Alcohol Dilution) has a spec, grav. of 0.928 at 15.6° C. (60° F.), or 0.920 at 25° C. (77° F.), and contains 53 per cent, by volume, or 45.5 per cent, by weight of absolute alcohol. ALCOHOL. 207 Table of the quantity of absolute Alcohol, by weight and by volume, con- tained in 100 parts ojt aqueous Alcohol of different specif c gravities. Temperature 15° C. (59° F.)- Specific gravity. 100 volumes contain: .-a. 100 parts by weight con- Specific gravity. 100 volumes contain: 100 parts by weight con- tain : Alcohol. Alcohol. W ater. tain: A. Icohol. Alcohol. 1 Water. 0.7951 100 0.00 100.00 0.9348 50 53.72 42.53 0.8000 99 1.28 98.38 0.9366 49 54.70 41.59 0.8046 98 2.54 96.83 1 0.9385 48 55.68 40.66 0.8089 97 3.77 95.35 0.9403 47 56.66 39.74 0-8130 96 4.97 93.89 1 0.9421 46 57.64 38.82 0.8169 95 6.16 92.45 0.9439 45 58.61 37.90 0.8206 94 7.32 91.08 0.9456 44 59.54 37.00 0.8242 93 8.48 89.72 0.9473 43 60.58 36.09 0.8277 92 9.62 88.37 0.9490 42 61.50 35-18 0.8311 91 10.76 87.04 0.9506 41 62.46 34.30 0-8344 90 11.88 85.74 0.9522 40 63.42 33.40 0.8377 89 13.01 84.47 0.9538 39 64.37 32.52 0.8409 88 14.12 83.22 0.9553 38 65.32 31.63 0.8440 87 15.23 81.96 0.9568 37 66.26 30.75 0.8470 86 16.32 80.72 0.9582 36 67.20 29.88 0.8500 85 17.42 79.51 0.9595 35 68.12 29.01 0.8530 84 18.52 78.29 0.9607 34 69.04 28.14 0.8559 83 19.61 77.09 0.9620 33 69.96 27.27 0.8588 82 20.68 75.91 0.9633 32 70.89 26.41 0.8616 81 21.76 74.75 0.9645 31 71.80 25.56 0.8644 80 22.82 73.59 0.9657 30 72.72 24.70 0.8671 79 23.90 72.43 0.9668 29 73.62 23.85 0.8698 78 24.96 71.30 0.9679 28 74.53 23.00 0.8725 77 26.03 70.16 0.9690 27 75.43 22.16 0.8752 76 27.09 69.04 0.9700 26 76.33 21.31 0.8778 75 28.15 67.93 0.9711 25 77.23 20.47 0.8804 74 29.20 66.82 0.9721 24 78.13 19.63 0.8830 73 30.26 65.72 0.9731 23 79.09 18.79 0.8855 72 31.30 64.64 0.9741 22 79.92 17.96 0.8880 71 32.35 63.58 0.9751 21 80.81 17.12 0.8905 70 33.39 62.50 0.9761 20 81.71 16.29 0.8930 69 34.44 61.43 0.9771 19 82-60 15.46 0.8954 68 35.47 60.38 0.9781 18 83.50 14.63 ; 0.8978 67 36.51 59.33 0 9791 17 84.39 13.80 0.9002 66 37.54 58.29 0.9801 16 85.29 12.98 0.9026 65 38.58 57.25 0.9812 15 86.19 12-15 0.9049 64 39.60 56.23 0.9822 14 87.09 11.33 0.9072 63 40.63 55.21 0.9833 13 88.00 10.51 0.9095 62 41.65 54.20 0.9844 12 88.90 9.69 0.9117 61 42.67 53.19 0.9855 11 89.80 8.87 0.9139 60 43.68 52-20 0.9867 10 90.72 8.06 0.9161 59 44.70 51.20 0.9878 9 91.62 7.24 0.9183 58 45.72 50.21 0.9890 8 92.54 6.43 0.9205 57 46.73 49.24 0.9902 7 93.45 5.62 0.9226 56 47.73 48.26 0.9915 6 94.38 4.81 0.9247 55 48.74 47.29 0.9928 5 95.30 4.00 0.9267 54 49.74 46.33 0.9942 4 96.24 3.20 0.9288 53 50.74 45.37 0.9956 3 97.17 2.40 0.9308 52 51.74 44.41 0.9970 2 98.11 1.60 0.9328 51 52.73 43.47 0.9985 1 99.05 0.80 208 MANUAL OF CHEMICAL ANALYSIS. Since, however, the temperature exercises a considerable ex- panding and contracting influence upon alcohol and its dilution with water, it is necessary to ascertain, simultaneously with the specific gravity, also the temperature of the sample; for this rea- son, the areometers (alcoholometers) constructed for determining the specific gravity of alcohol are provided with a thermometer, and differences in the temperature of the alcohol under estima- tion may readily be corrected by calculation based upon this rule : The number of degrees of temperature of the alcohol above or below 15° must be multiplied by four-tenths; the product is then to be added to the percentage of the absolute alcohol indicated by the specific gravity, when the temperature of the liquid was lower than 15° C., and subtracted, when it was higher. If, e. g., the spec. grav. of a sample is found to be 0.861, at a temperature of 5° C., its percentage of real alcohol would be, according to the preceding table, 81 per cent., by volume ; since, however, the alcohol was weighed at a tempera- ture 10° lower than the standard temperature of the above table, its specific gravity was accordingly greater. Therefore, in order to correct this difference, 10 has to be multiplied by four-tenths ; the product (=4) must be added to the percentage of alcohol (81) inferred from the spec, grav., and the sum (=85) expresses the real quantity of alcohol in 100 parts by volume. Examination: Alcohol should be perfectly neutral in its action upon litmus, wholly vaporizable by heat, and afford no coloration on the addi- tion of ammonia-water. Fusel oil (consisting principally of amylic alcohol, with traces of propylic, butylic, and other alcohols, free fatty acids or compound ethers) and aldehyde may be detected by mixing a por- tion of the alcohol with an equal volume of pure ether, and subsequently adding an amount of water equal to the volume of the mixture; the whole is shaken, and, when subsidence has taken place, the ethereal layer is decanted, and allowed to evapo- rate spontaneously in a shallow porcelain capsule. After the evaporation of the ether, the residue will give the characteristic odor of fusel oil, or of any flavors indicative of a previous employ- ment of the alcohol for the extraction of vegetable substances. The residue, if sufficient in amount, may be also further exam- ined by bringing it into a test-tube with a few drops of water, subsequently adding a very small quantity of sodium acetate, and a few drops of concentrated sulphuric acid, and gently warming the mixture; if fusel oil be present, the charac- teristic odor of amyl acetate (pear essence) will be developed. The presence of fusel oil may likewise frequently be detected by simply pouring a few grams of alcohol upon three or four times its volume of hot water, contained in a large beaker, and causing the mixture to flow to and fro, when, in proportion as the alcohol evaporates, the odor of the fusel oil will become more distinct. Aldehyde will also be further indicated by a dark coloration on the addition of ammonia-water, or when a small portion of the ALCOHOL. 209 alcohol is warmed with a fragment of pure potassium hydrate; as also by the reduction of metallic silver, on the addition of a few drops of a solution of argentic nitrate to the alcohol, and gently warming. Methyl Alcohol.—Among the several methods for the detection of methyl alcohol as an admixture in ethyl alcohol, the following two are preferable: 1. About 150 cubic centimeters-of the alcohol are digested for an hour with 20 grams of plumbic carbonate, and filtered, the filtrate is then distilled from a water-bath, and the first 20 cubic centimeters of the distillate treated with 1 cubic centi- meter of test-solution of potassium permanganate; the color should not disappear within one or two minutes, otherwise methyl alcohol is indicated. 2. Ten grams of powdered potassium bichro- mate are dissolved, in a flask, in about 75 cubic centimeters of water, 15 grams of concentrated sulphuric acid are then added, and subsequent!}7 about 10 grams of the alcohol to be examined. Fig. 85. The flask is then connected with a condenser (Fig. 85), and, after having been allowed to stand for about a quarter of an hour, gentle beat is applied until about two-thirds of the liquid has distilled over. The distillate (which will contain aldehyde and acetic acid from the oxidation of the ethyl alcohol, and also formic acid from the oxidation of the methyl alcohol, if the latter were present) is then slightly supersaturated with crystallized sodium carbonate, and evaporated at a gentle heat, with the re- peated addition of water, if necessary, until the odor of aldehyde has entirely disappeared. The solution is then filtered into a test-tube, slightly acidulated with acetic acid, a few drops of solu- tion of argentic nitrate added, and the mixture gently warmed. If the liquid merely darkens a little, but remains quite trans- 210 MANUAL OF CHEMICAL ANALYSIS. lucent, the alcohol is free from methyl alcohol; but if a dark- brown or black precipitate of reduced silver separates, and the test-tube, after being rinsed and filled with water, shows upon its interior a bright metallic mirror, which, when seen against white paper, appears brown by transmitted light, the alcohol is methylated. ALCOHOL AMYLICUM. Amylic Alcohol. Fusel Oil. Ger. Amylalcoliol, Fuselol; Fr. Alcohol amylique ; Sp. Alcohol amilico. CsH120* = CHA CH,/ CH-CH2-CEL-0H; 88. Amylic alcohol, as obtained by fractional distillation from fusel oil, is a mixture of two isomeric alcohols, having nearly the same boiling-point, in consequence of which they have not yet been perfectly separated from each other; the one deviates a ray of polarized light to the left, the other is inactive, or possibly pos- sesses the property of right-handed polarization. The mixture, when treated with concentrated sulphuric acid, yields two isomeric amyl-sulphuric acids, which are also distinguished from each other by the varying solubility of their barium salts. Pure amylic alcohol is a colorless or nearly colorless, mobile, oily liquid, of a strong, offensive odor, and acrid, burning taste; its spec. grav. is 0.818 at 15° 0. (59° F.), and its boiling-point between 132° and 133° C. (269.6°-271.4° F.); it solidifies at about —23° C. (—9.4° F.). When dropped upon water, it floats upon the surface like an oil, but is soluble in about 40 parts of water; it is miscible, in all proportions, with alcohol, ether, carbon bisul- phide, chloroform, and essential and fatty oils, and dissolves iodine, sulphur, phosphorus, camphor, and many resins. When mixed with an equal volume of concentrated sulphuric acid, it forms a violet-red mixture, from which, upon dilution with much water, the amylic alcohol is for the most part separated unchanged ; if the mixture, however, is allowed to stand for several hours, no separation takes place upon dilution, in consequence of the forma- * Of the alcohols possessing the empirical formula CsH]20, eight modifica- tions are theoretically possible; viz., 4 primary, 3 secondary, and 1 tertiary, of which number, five are now known, viz., two primary: (1) Normal amylic alcohol, CH3-CH/-CH2-CH2-CH2-OH. (2) The commercial amylic alcohol of the above constitution. Two secondary: (3) Isoamylic alcohol, ch3-ch2-ch2-ch^^. And one tertiary: (5) Pseudoamylie alcohol, or Ethyl-dimethyl carbinol, (4) Amylene hydrate, ch.\OH-chhates may be detected by shaking a little of the powder with warm water, in a test-tube, filtering, and evaporating the filtrate to dryness; the obtained residue is then dissolved in a little dilute nitric acid, when effervescence will indi- cate soluble carbonates, and the resulting diluted solution, when tested with barium chloride, will afford a white precipitate if sul- phates are present, both of which impurities would indicate an insufficient washing of the preparation. Copper and Zinc.—The portion remaining undissolved upon the filter, after extraction with water, as in the preceding test, is FERRUM. 341 digested, in a test-tube, with a little solution of ammonium car- bonate, for about one hour. The liquid is then filtered; a bluish color of the filtrate would indicate the presence of copper, and the formation of a white precipitate upon the addition of a few drops of ammonium sulphide, that of zinc. If 8 grams of the saccharated carbonate of iron be dissolved in water with an excess of hydrochloric acid, and the solution mixed with 33 cubic centimeters of standard solution of potassium bichromate (page 91), the mixture should still afford a blue color or precipitate on the addition of solution of potassium ferricya- nide, indicating the presence of at least 15 per cent, of ferrous carbonate. FERRI CHLORIDUM. FERPI PERCHLORIDUM. FERRUM SESQUI-CHLORATUM. Chloride of Iron. Perchloride of Iron. Ferric Chloride. Ger. Eisenchlorid ; Fr. Perc.hlorure de fer; Sp. Percloruro de hierro. Fe2Cl6+12H20; 540.2: or Fe2Cl6+6H20; 432.2. Orange-yellow, crystalline masses, having a radiate structure, and containing 12 molecules (39.93 per cent.) of water, or large, brownish-red, rhombic tables, containing 6 molecules (24.94 per cent.) of water of crystallization. The normal chloride, Fe2Cl6 4- 12HaO, melts at 36° C. (96.8° F.) to a liquid of a deep brownish-red color; upon more strongly heating, it becomes partially decom- posed, losing at first water and hydrochloric acid, whilst a portion of the chloride sublimes in the form of anhydrous, brown, irides- cent plates or hexagonal tables, which exhibit a red color by transmitted, and a green metallic lustre by reflected light, and leaving a residue of ferric oxide. Ferric chloride is deliquescent, freely soluble in water, alcohol, and glycerin, and also, but less readily, in ether and chloroform; it is abstracted from its aqueous solution by ether, and also, to a less extent, by chloroform. A strong aqueous solution, of a spec. grav. of 1.405, forms the officinal Liquor ferri chloridi. This, as well as the solution of the salt, has an acid and strongly styptic taste, and an acid reaction on test-paper ; when diluted with water, they give a blue precipitate with potassium ferrocyanide, a white one with argentic nitrate, and a bulky reddish-brown precipitate of ferric hydrate, upon the addition of the alkaline hydrates in excess. ” Examination: Ferric chloride should yield a complete and clear solution with water and with alcohol; if a reddish, insoluble residue remains, the chloride has undergone partial decomposition. 342 MANUAL OF CHEMICAL ANALYSIS. Ferrous chloride is detected, in the largely diluted solution, by the formation of a blue precipitate with potasssium ferrioyanide. Fixed Impurities, other Metallic Chlorides, and Nitric and /Sul- phuric Acids.—A small portion of the ferric chloride is dissolved in about ten times its weight of water, the solution heated to boil- ing, and ammonia-water, in slight excess, subsequently added, until the iron is completely precipitated, or until a little of the clear solution no longer affords a blue coloration upon the addition of a solution of potassium ferrocvanide. The liquid is then filtered, and subsequently tested in separate portions as follows: Fixed impurities will bo recognized by evaporating a portion of the liquid to dryness, and strongly heating the residue upon platinum-foil. ■Copper and Zinc.—The presence of copper will be indicated by a blue color of the ammoniacal solution, and, if present, the solu- tion should be slightly acidulated with hydrochloric acid, and subsequently saturated with hydrogen sulphide, when the copper will be completely precipitated as brownish-black cupric sulphide; after the removal of the latter by filtration, the solution is again supersaturated with ammonia-water, and tested with ammonium sulphide, when a white precipitate will indicate the presence of zinc. Sulphuric acid will be indicated by a white precipitate when a portion of the diluted solution, slightly acidulated with hydro- chloric acid, is tested with barium chloride. Fig. 116. Nitric acid may be detected bj slightly acidulating a portion of the diluted solution with sulphuric acid, and by testing it, in two portions, with solution of indigo and solution of potassium per- FERRUM. 343 inanganate; a decoloration of the faintly colored solutions, upon gently warming, would indicate nitric acid. The presence of nitric acid may be confirmed by mixing a por- tion of the solution, previously neutralized with sulphuric acid, with a strong solution of ferrous sulphate, and by the subsequent careful addition of concentrated sulphuric acid, so as to form two layers (Fig. 116); a brown coloration at the line of contact of the two liquids will ensue, if nitric acid or oxides of nitrogen be present. FERRI CITRAS. FERRUM CITRICUM OXYDATUM. Citrate of Iron. Ferric Citrate. Ger. Citronensaures Eisenoxyd ; Fr. Citrate de fer ; Sp. Citrato de liierro. Fe,(C„H50,)s + 611,0 ; 597.8. Thin, transparent scales, of a garnet-red color, permanent in the air; when heated on platinum-foil, they are charred without fusing, and without the evolution of an ammoniacal odor (distinction from ammonio-ferric citrate); when completely incinerated, aided, if necessary, by the addition of a few drops of nitric acid, red ferric oxide, Fe203, amounting to 26.76 per cent, of the original weight, is left, which, when cool, should have no alkaline reaction upon moist turmeric or litmus paper (distinction from potassio- ferric tartrate). Ferric citrate is slowly but completely soluble in cold, and readily in hot, water, and insoluble in alcohol; its aqueous solu- tion has a yellow color, a mild chalybeate taste, and an acid reac- tion upon litmus; it is not precipitated by ammonia-water, but is rendered darker in color, and affords a precipitate of ferric hydrate when heated with a solution of potassium hydrate; when largely diluted with water, and slightly acidulated with hydrochloric acid, it yields a deep blue color upon the addition of a few drops of solution of potassium ferrocyanide. Examination: Ferric citrate when shaken with cold concentrated sulphuric acid should not impart any color to the latter, even after several hours, and should produce no effervescence when added to a cold solution of sodium carbonate. Ammonium salts, or an admixture of ammonio-ferric citrate, may be detected by the odor of ammonia, when a little of the ferric citrate is heated, in a test-tube, with a concentrated solution of potassium hydrate. Ferric tartrate may be detected by completely precipitating a warm solution of ferric citrate with potassium hydrate, and test- 344 MANUAL OF CHEMICAL ANALYSIS. ing the colorless filtrate by slightly supersaturating a portion of it with acetic acid; when the solution is very dilute, it is first reduced by evaporation, and, when cold, tested with a few drops of a concentrated alcoholic solution of potassium acetate ; a white crystalline precipitate, occurring at once or after some time, would indicate tartrate. Another portion of the filtrate is precipitated with calcium chloride, and filtered; the filtrate, when heated to boiling, should yield a white, granular precipitate of calcium citrate, which redissolves on cooling, being confirmatory evidence of the identity of a citrate. FERRI ET AMMONII CHLORIDUM. AMMONIUM OHLORATUM FERRATUM. AMMONIUM MURIATICUM MARTIATUM. Ammonio-Chloride of Iron. Ammonio-Ferric Chloride. Ger. Eisensalmiak ; Fr. Clilorure de fer et d’ammoniaque ; Sp. Cloruro de hierro y de amoniaco. An orange-yellow, crystalline powder, somewhat deliquescent, readily soluble in water or glycerin, and to some extent in alco- hol, forming a yellow, transparent solution, which has an acid reaction upon litmus. Its aqueous solution gives a copious rust- brown precipitate with alkaline hydrates, and, when very dilute, a deep-blue one with potassium ferrocyanide, and a white, curd v one with argentic nitrate; when heated with a concentrated solu- tion of potassium hydrate, it develops the odor of ammonia, and deposits ferric hydrate. Examination; One part of the salt should afford a complete and transparent solution with five parts of water ; a reddish-brown insoluble residue would indicate decomposition of the ferric chloride by exposure to too strong a heat while drying the salt. The solution thus obtained should not afford a blue coloration upon the addition of two drops of a freshly prepared solution of potassium ferricyanide (absence of ferrous salt). Zinc and Copper.—The warm diluted aqueous solution is com- pletely precipitated by the addition of ammonia-water in slight excess, and subsequently filtered; a blue coloration of the liquid will reveal the presence of copper; if the latter be absent, the filtrate may then be directly tested with ammonium sulphide, when a white precipitate will indicate the presence of zinc; if, however, copper be present, the ammoniacal liquid is first slightly supersaturated with hydrochloric acid, and the copper completely FERRUM. 345 precipitated by hydrogen sulphide, when the liquid, after filtra- tion, will afford upon the addition of ammonia-water a white precipitate, if zinc be present. FERRI ET AMMONII CITRAS. FERRUM ET AMMONIUM CITRICUM. FERRUM CITRICUM AMMONIATUM. Citrate of Iron and Ammonium. Ammonio-ferric Citrate. Ger. Citronensaures Eisennxyd-Ammomum ; Fr. Citrate de fer et d’ammoniaque ; Sp. Citrato de hierro amoniacal. Thin, transparent, garnet-red scales, of a slightly sweetish and astringent taste; they evolve, when heated, water and ammonia, and, when completely incinerated upon platinum-foil, leave be- hind about 25 per cent, of ferric oxide, which should not change the color of moistened red litmus-paper (evidence of the absence of potassio-ferric salts). Heated with a concentrated solution of potassium hydrate, ammonia is evolved (distinction from ferric citrate), and ferric hydrate is deposited. Ammonio-ferric citrate is readily soluble in water, glycerin, and diluted alcohol, but not in strong alcohol or ether ; its aqueous solution is neutral or has a slightly alkaline reaction, remains un- altered, or is but slightly darkened in color on the addition of ammonia water, and is not affected by solution of potassium ferro- cyanide until after the addition of a mineral acid, when a deep blue color or precipitate is produced. Examination: Ammonio-ferric tartrate may be recognized, as an incidental or fraudulent admixture or substitution, by completely precipitating a not too dilute aqueous solution of the salt with potassium hydrate; the.liquid is heated nearly to boiling, and, when cool, filtered ; one portion of the colorless filtrate is examined by slight supersaturation with acetic acid, and by the subsequent addition of a little alcoholic solution of potassium acetate, and allowing the liquid to stand for some hours; the formation of a white, crystalline deposit would indicate tartrate. Another portion of the filtrate is precipitated with calcium chloride, filtered, and the filtrate heated to boiling. A white pre- cipitate of calcium citrate, disappearing again on cooling, will bear evidence of the identity of a citrate. 346 MANUAL OF CHEMICAL ANALYSIS. FERRI ET AMMONII SULPHAS. FERRUM ET AMMONIUM SULFURICUM. FERRUM SULFURICUM OXYDATUM AMMONIATUM. Sulphate of Iron and Ammonium. Iron Alum. Ammonio-Ferric Sulphate. Ger. Schwefelsaures Eisenoxyd-Ammonium (Eisen-ammonium-alaun) ; Fr. Sulfate de fer et d’ammoniaque ; Sp. Sulfato de hierro ammoniacal. Fe2(NH4)2(S04)4 + 24H20. Pale-violet, octahedral crystals (Fig. 86, page 213), containing 24 molecules (44.8 per cent.) of water of crystallization, and efflo- rescing by exposure to the air. Exposed to heat, they undergo aqueous fusion, lose the water of crystallization, swell up, and leave a pale-brown residue. When the crystals, or an aqueous solution of the salt, is heated with a concentrated solution of potassium hydrate, ammonia is evolved, which may be recognized by its odor, and a precipitate of ferric hydrate is produced. Ammonio-ferric sulphate is soluble in 3 parts of water at 15° C. (59° F.), and in 0.8 part of boiling water; it is less soluble in glycerin, and insoluble in alcohol, ether, and chloroform. Its aqueous solution has a slightly acid reaction, a sour, astringent taste, and becomes partially decomposed on boiling, with the separation of an insoluble, yellowish-brown, basic salt; it yields a blue precipitate with potassium ferrocyanide, a brown one with the alkaline hydrates, and a white one, insoluble in acids, with barium nitrate or chloride. When the solution of ammonio-ferric sulphate is completely precipitated with potassium hydrate, and the filtrate slightly supersaturated with hydrochloric acid, it should not afford a white, gelatinous precipitate upon the subsequent addition of an excess of ammonia-water (absence of aluminium); the solution of the salt, when completely precipitated by ammonia water, should afford a filtrate, which, upon evaporation to dryness and subse- quent ignition, should leave no permanent residue, nor impart a violet color to the non-luminous flame (absence of potassium salts). FERRUM ET AMMONIUM TARTARICUM. FERRUM TARTARICUM AMMONIATUM. FERRI ET AMMONII TARTRAS. Tartrate of Iron and Ammonium. Ammonio-Ferric Tartrate. Ger. Weinsaures Eisenoxyd- Ammonium ; Fr. Tartrate de fer et d’ammoniaque ; Sp. Tartrato de hierro ammoniacal. Transparent, deep-red scales, of a sweet taste, and of a rust- brown color when reduced to powder; when heated in a test-tube, FERRUM. the salt emits vapors of water and ammonia, and, when com- pletely incinerated, by exposure to a red heat, it leaves a residue of ferric oxide amounting to about 25 per cent, of its weight. Heated with potassium hydrate, it evolves the odor of ammonia, and deposits ferric hydrate. Ammonio-ferric tartrate is slowly but freely soluble in water and in glycerin, but insoluble in alcohol and ether ; its solution is neutral or slightly alkaline, remains unaltered, or is but slightly darkened in color on the addition of ammonia-water, and, when cold, is not precipitated by the fixed alkaline hydrates or carbonates, but is so upon boiling it with either of these reagents. Its solu- tion is not rendered blue by potassium ferrocyanide, unless acid- ulated with a few drops of a mineral acid. When completely precipitated by potassium hydrate, the filtrate, if not too dilute, gradually yields, after supersaturation with acetic acid, a white, crystalline deposit of acid potassium tartrate, but should afford no precipitate with hydrogen sulphide. The aqueous solution of ammonio ferric tartrate, when acidu- lated with a few drops of hydrochloric acid, should afford upon saturation with hydrogen sulphide but a white turbidity of sul- phur; a dark turbidity would indicate other metals (copper); if required, the nature of the precipitate of the sulphides may be ascertained, and the metals contained therein recognized, by the method described on pages 52-56. FERRI ET POTASSII TARTRAS. FERRUM ET POTASSIUM TARTARICUM. TARTARUS FERRATUS. Tartrate of Iron and Potassium. Potassio-Ferric Tartrate. Ger. Weinsaures Eisenoxyd-Kalium ; Fr. Tartrate de fer et de potasse ; Sp. Tartrato de kierro y potasa. Transparent, rubj-red scales, of a sweetish and slightly astrin- gent taste; when heated, they emit at first the odor of burnt sugar, and leave, upon incineration at a red heat, a residue which, when cold, changes the color of moistened red litmus-paper to blue, and effervesces when moistened with a drop of hydrochloric acid. Potassio-ferric tartrate is freely soluble in water and in gly- cerin, but scarcety in alcohol; its solution is neutral or slightly alkaline, remains unaltered or is but slightly darkened in color on the addition of ammonia-water, and, at ordinary temperatures, gives no precipitate with the fixed alkaline hydrates or car- bonates, but, upon boiling, a reddish-brown precipitate of ferric hydrate is produced; with potassium ferrocyanide it affords no 348 MANUAL OF CHEMICAL ANALYSIS. reaction until after the addition of a mineral acid, when the solu- tion, even when very dilute, assumes a deep blue color. If the iron be completely precipitated from the solution by boiling with a solution of potassium hydrate, and the filtrate slightly super- saturated with acetic acid, it gives, on cooling, if not too dilute, a crystalline deposit of acid potassium tartrate, but should afford no precipitate with hydrogen sulphide. The aqueous solution of potassio-ferric tartrate, when acidulated with a few drops of hydrochloric acid, should afford upon saturation with hydrogen sulphide but a wdiite turbidity of sulphur; a dark turbidity would indicate other metals (copper) ; if required, the nature of the precipitate of the sulphides may be ascertained, and the metals contained therein recognized, by the method described on pages 52-56. When heated with a solution of potassium hydrate, po- tassio-ferric tartrate should not develop the odor of ammonia (distinction from ammonio-ferric tartrate). FERRI ET QUININiE CITRAS. FERRUM ET CHININUM CITRICUM. CHININUM FERRO- CITRICUM. Citrate of Iron and Quinine or Quinia. Quinine Ferric Citrate. Ger. Chininhaltiges Citronensaures Eisenoxyd ; Pr. Citrate de fer et de quinine ; Sp. Citrato de lnerro y quinina. Thin, transparent scales, varying in their color from a yellowish- brown, with a tint of green, to a reddish-brown, according to the thickness of the scales. When strongly heated, they are decom- posed with the evolution of white fumes, and leave, upon incine- ration, a residue of ferric oxide, which should not change moist- ened red litmus-paper (evidence of the absence of alkaline citrates). Quinine ferric citrate is slowly but freely soluble in cold, and readily in hot, water, but insoluble in alcohol and ether ; its solution is neutral or slightly acid, and has a bitter, mild, cha- lybeate taste; it gives, at ordinary temperatures, a white precipi- tate of quinine with ammonia-water, and the solution assumes a deeper color; but no ferric hydrate is thrown down; when the precipitate is collected upon a filter, washed with a few drops of cold water, and then dissolved in a little chlorine-water, the solu- tion will assume an emerald-green color upon the addition of a few drops of ammonia-water (evidence of the presence of quinine, and distinction from cinchonine and cinchonidine). Solution of quinine ferric citrate gives a brown precipitate of ferric hydrate and quinine with a solution of potassium or sodium hydrate, and with ammonia-water, when heated; a blue one with solution of FERRUM. 349 potassium ferrocyanide, when acidulated with a mineral acid, and a grayish-black one with tannic acid. Examination: The absence or admixture of cheaper scaled ferric salts may be ascertained: 1. By the bitter taste, while the other scaled ferric salts, with the exception of strychnine ferric citrate, have a more or less sweetish taste. 2. By the formation, in the cold, of a white precipitate with ammonia-water, which responds to the tests and reactions of quinine, while the ferric citrates and tartrates, and their more soluble combinations with alkaline salts, yield, with the same reagent, no precipitate at all at ordinary temperatures. 3. By giving no odor of ammonia, nor white fumes with a glass rod, moistened with acetic acid, wrhen heated in a test-tube with a solution of potassium or sodium hydrate. Any admixture of ammonio-ferric salt would be recognized by this test. In order to ascertain the purity of quinine ferric citrate or to determine the proper percentage of quinine contained therein, the following method of examination may be employed. Four grams of the scaled salt are dissolved in 30 cubic centimeters of water, in a capsule, with the aid of a gentle heat. The solution, after being allowed to cool, is transferred to a glass separating funnel, the rinsings of the capsule added thereto, then an aqueous solu- tion of 0.5 gram of tartaric acid added, and the whole well mixed. Solution of sodium hydrate in considerable excess is now added, and the precipitated alkaloid extracted by agitating the mixture with four successive portions of chloroform of 15 cubic centi- meters each. After being allowed to subside, the chlorof'ormic layers are separated, subsequently combined, evaporated in a weighed capsule on a water-bath, and the residue finally dried at 100° C. (212° F.), until it ceases to lose weight. The obtained residue should weigh 0.48 gram, corresponding to 12 per cent, of dry quinine. FERRI ET STRYCHNINiE CITRAS. FERRUM ET STRYCHNINUM CITRICUM. STRYCHNINUM FERRO-CITRICUM. Ger. Strychninlialtiges cit'ronensaures Eisenoxyd ; Fr. Citrate de fer et de strychnine ; Sp. Citrato de hierro y estricnina. Citrate of Iron and Strychnine. Strychnine Ferric Citrate. Thin, transparent, garnet-red scales, deliquescent on exposure to the air. When strongly heated, they are decomposed with the evolution of white fumes, and leave, upon incineration, a residue 350 MANUAL OF CHEMICAL ANALYSIS. of ferric oxide, which should not change moistened red litmus- paper (evidence of the absence of alkaline citrates). Strychnine ferric citrate is readily and completely soluble in water, but only slightly soluble in alcohol. Its aqueous solution possesses a slightly acid reaction, and a bitter, mild, chalybeate taste ; when heated, in a test-tube, with a concentrated solution of potassium hydrate, it develops the odor of ammonia, and a brown- ish-red precipitate of ferric hydrate is produced. If the solution of the salt be boiled with an excess of solution of potassium hydrate, filtered, and the concentrated and cooled filtrate precipitated by solution of calcium chloride, and again filtered, the filtrate thus obtained, when heated to boiling, will yield a white granular pre- cipitate of calcium citrate, which, however, becomes mostly redis- solved on cooling. The dilute aqueous solution of the salt is not affected by solution of potassium ferrocyanide until after the addition of a mineral acid, when a deep blue color or precipitate is produced. Examination: The identity of strychnine ferric citrate maybe determined and its purity approximately ascertained by dissolving 1 gram of the salt in about four times its weight of water, adding thereto 1 gram of a concentrated solution of potassium hydrate, and agitating the mixture with small successive portions of chloroform ; the chlo- roformic layers are separated from the aqueous mixture, and, after evaporation, should leave a residue answering to the reac- tions and tests of strychnine, and corresponding in amount to one per cent, of the weight of salt employed. FERRI FERROCYANIDUM. Ferrocyanide of Iron. Prussian Blue. Ferric Ferrocyanide. FERRUM FERROCYANATUM. Ger. Eisencyaniir-cyanid (Berliner Blau); Fr. Cyanure de fer (Bleu de Prusse); Sp. Hidrocianato de liierro. Fe7(CN)„ = 3[Fe(CN)J + 4[Fe(CN)a]; 859.3. A deep-blue, tasteless powder, or hard, brittle, blue masses, showing, on the freshly fractured surfaces, a beautiful bronzed lustre, which disappears when they are powdered. When heated in the air, it burns with the development of colorless vapors, emitting the odor of ammonia and hydrocyanic acid, and leaving a residue of ferric oxide ; exposed to a high temperature in a closed vessel, it gives off’ water, ammonium cyanide, and ammo- nium carbonate, and carbide of iron is left behind. Ferric ferrocyanide is insoluble in water, glycerin, and alcohol, and in diluted acids, with the exception of oxalic acid, which dis- FERRUM. 351 solves it, with a deep-blue color. Concentrated sulphuric acid converts it into a white pasty mass, which again assumes a blue color upon the addition of water; it is also decomposed by con- centrated hydrochloric and nitric acids. Alkaline hydrates and carbonates decompose it, upon heating, with the formation of soluble alkaline ferrocyanide, and leaving rust-brown ferric hydrate behind. Commercial Prussian blue is not invariably pure ferric ferro- cyanide, but generally contains aluminium and potassium salts, and frequently some uncombined ferric hydrate. These impuri- ties may be detected by boiling the triturated Prussian blue with dilute hydrochloric acid, and adding to the filtrate an excess of ammonia-water, when the hydrates of aluminium and iron are precipitated, while pure ferric ferrocyanide, treated in this man- ner, yields no precipitate. If it is desired to examine the precipi- tate for aluminium, it is collected upon a filter, washed, and treated with a warm solution of potassium hydrate; the filtered solution will then afford a white flocculent precipitate upon the addition of a solution of ammonium chloride, if aluminium be present. Examination: Mineral Admixtures.—A small portion (about 2 grams) of the ferric ferrocyanide is heated, in a porcelain crucible, to redness; when cool, the residue is treated with warm hydrochloric acid, which should afford a complete and clear solution, with slight effervescence; an insoluble residue would indicate fixed mineral admixtures (calcium or barium sulphates or silicates). Metals.—To the solution obtained in the preceding test, a little potassium chlorate is added, and the solution boiled until the odor of chlorine ceases to be evolved; it is then diluted, filtered, and the filtrate divided into two portions; these are heated, and the one is precipitated with a solution of potassium hydrate, the other with ammonia-water, in excess ; after a while, they are filtered, and each of the alkaline filtrates is tested with ammonium sulphide ; a black precipitate, in the potassa solution, would indicate lead; a blue coloration of the ammoniacal liquid, and a brownish-black precipitate upon the addition of ammonium sulphide, will indicate copper; a white turbidity, in either of the liquids, upon the addition of ammonium sulphide, shows zinc to be present. For the detec- tion of zinc in the presence of lead or copper, the alkaline solution must be first slightly supersaturated with hydrochloric acid, and the lead or copper subsequently completely precipitated by hydrogen sulphide; the liquid, after filtration, will then afford, upon the addition of ammonia-water, a white precipitate, if zinc be present. • Earthy Carbonates.—The ammoniacal liquid of the preceding test for copper and zinc, from which the latter, if present, have been completely removed, either by saturation with hydrogen sulphide or by the addition of ammonium sulphide, is tested with ammo- 352 MANUAL OF CHEMICAL ANALYSIS. nium carbonate; an ensuing white precipitate would indicate the presence of barium or calcium ; after the removal of the latter by filtration, solution of sodium phosphate is added, when the forma- tion of a white crystalline precipitate will reveal the presence of viaynesium. FERRI HYFOPHOSPHIS. FERRUM HYPOPHOSPHOROSUM. Hypophosphite of Iron. Ferric Hypophosphite. Ger. Unterpliospliorigsaures Eisenoxyd ; Fr. Hypophosphite de fer ; Sp. Hipofosfito de hierro. Fea(H2P02)6; 501.8. A white or grayish-white, odorless powder, permanent in the air; when heated, in a dry test tube, it evolves spontaneously inflammable vapors of hydrogen phosphide, with eonsiderable intumescence, leaving behind ferric pyrophosphate; when heated with a solution of potassium or sodium hydrate, it is decomposed, and assumes a reddish brown color. Since hypophosphorous acid is very prone to absorb oxygen, the salt is readily decomposed by all oxidizing agents. Ferric hypophosphite is insoluble in cold water, and, when dry, is but sparingly soluble in hypophosphorous acid, but readily dissolves in that liquid when in the moist hy- drated condition; it is dissolved by diluted hydrochloric ac;d, forming a yellow solution, which, when largely diluted, gives a blue precipitate with potassium ferrocyanide, and is also readily soluble in solutions of ferric sulphate and of sodium hypophos- phite, and unites with alkaline citrates to form compounds which are readily soluble in water, and of a green color. Examination: Ferric phosphate may be recognized by an insoluble residue when a small portion of the salt is dissolved in acetic acid. The acetic solution should afford no precipitate upon the addition of solution of ammonium oxalate; an ensuing white precipitate, soluble in hydrochloric acid, would reveal the presence of cal- cium. FERRI IODIDUM. FERRUM IODATUM. Ger. Eisenjodiir; Fr. Iodure de fer ; Sp. Ioduro de hierro. Fel2; 309.1. Iodide of Iron. Ferrous Iodide. Opaque plates or masses, of an iron-gray color, metallic lustre, and crystalline fracture, or, when obtained by the careful evapo- FERRUM. 353 ration of its concentrated aqueous solution, bright green crystals, haying the composition FeI24-4H20, which rapidly suffer oxida- tion. When heated in a dry test-tube, ferrous iodide fuses, and emits violet iodine vapors, finally leaving behind ferric oxide. Ferrous iodide is very deliquescent; it is soluble in its own weight of water, and also in alcohol and glycerin, forming yellow- ish-green solutions, having a styptic taste; its aqueous solution gives a copious blue precipitate with potassium ferricyanide, and, after the addition of a minute quantity of chlorine-water, assumes a fine blue color upon the addition of a little mucilage of starch. Ferrous iodide and its solutions rapidly oxidize, the latter forming a rust-brown sediment, the former becoming less soluble in water, and yielding a brown solution, one drop of which, when diluted with a little water, and subsequently shaken with a few drops of chloroform, imparts to the latter a beautiful violet coloration, which, however, is not the case when the ferrous iodide is fresh, and not yet partly oxidized. Ferrous iodide is decomposed by, and therefore incompatible with, acids, the alkaline hydrates and carbonates, and those metallic salts which form insoluble iodides. The oxidation of ferrous iodide is greatly obviated by its ad- mixture with sugar. Upon this fact, the preparation of Ferri IODIDUM SACCHARATUM and of Syrurus ferri IODIDI are based ; both share the chemical properties and reactions of the ferrous iodide. The syrup may be preserved without decomposition, when kept in a sunny place, in small, well-corked vials, containing a piece of clean, bright iron wire. FERRI LACTAS. FERRUM LACTICUM. Lactate of Iron. Ferrous Lactate. Ger. Milclisaures Eisenoxydul; Fr. Lactate de fer ; Sp. Lactato de hierro. Fe(C3H503)2 + 3Ii20 ; 287.9. Greenish-white, needle-shaped crystals, crystalline crusts or grains, or a greenish-white powder,* containing three molecules * The ferrous lactate of the German manufacturers and shops occurs as a yellowish or grayisli-green powder, and is obtained by the following process, which is least subject to the formation of peroxide : An alcoholic solution of sodium lactate is exactly decomposed by a concentrated aqueous solution of ferrous chloride. AlloAved to stand for twenty-four hours, in a filled and closely stoppered bottle, in a cool place, the ferrous lactate separates in a thick, crystalline crust, which, after the mother liquor has been removed, is broken by a wooden spatula, and then transferred to a cloth, washed with a. little alco- hol, and afterward subjected to a moderate pressure, under a small screw-press. The resulting salt cake is broken, dried at a gentle heat, and finally triturated. MANUAL OF CHEMICAL ANALYSTS. (18.8 per cent.) of water of crystallization, which are eliminated, without decomposition of the salt, by heating to 100° C. (212° F.) in a current of hydrogen. When heated, with exposure to the air, the salt acquires at temperatures above 60° C. (140° F.) a gray or brownish color, becomes finally black, and, at 100° C. (212° F.), is chiefly converted into ferric salt; when more strongly heated, the salt froths up, with the evolution of white, acid, inflammable fumes, becomes black, and, when completely incinerated, leaves a residue amounting to 27.8 per cent, of its weight of red ferric oxide, which, when cold, should not act upon moistened red litmus-paper (evidence of the absence of alkaline salts). Ferrous lactate is slowly soluble in 40 parts of water at 15° C. (59° F.), and more readily in 12 parts of boiling water, but is almost insoluble in alcohol. Its aqueous solution is more or less turbid, and of a yellowish-green color and acid reaction, and has a mild, sweetish, chalybeate taste; by exposure to the air, or more quickly upon boiling, it assumes a brown color, in conse- quence of its oxidation to ferric salt, and, upon protracted boiling, ferric hydrate is deposited. The concentrated aqueous solution of the salt affords upon the addition of solution of the alkaline hydrates a yellowish precipitate of ferrous hydrate, and yields when saturated with hydrogen sulphide, particularly upon warm- ing, an abundant precipitate of ferrous sulphide. The clear, filtered, aqueous solution should produce upon the addition of a few drops of a solution of potassium ferrocyanide but a slight blue coloration, and should afford with plumbic acetate but a slight opalescence (evidence of the absence of more than traces of ferric salt, and of sulphuric, hydrochloric, tartaric, citric, and malic acids); when acidulated with hydrochloric acid, it should afford upon saturation with hydrogen sulphide but a slight opa- lescence (absence of foreign metals, lead, copper, etc). Examination: In addition to the above-described characters and tests, ferrous lactate should be further examined for the following substances: Mineral Impurities.—A small portion of the ferrous lactate is completely incinerated in a small porcelain crucible, and the resi- due subsequently treated with boiling water and filtered; .the filtrate must neither act upon test-paper, nor leave any residue upon evaporation on platinum-foil. The ignited residue of ferric oxide is then treated with warm hydrochloric acid, in which it should be completely soluble, and the solution, after warming with a few drops of nitric acid, or the addition of a little chlorine- water, is diluted with water, filtered, heated to boiling, and finally completely precipitated by ammonia-water. The liquid, after fil- tration, evaporation to dryness, and subsequent ignition, should leave no residue ; when tested with ammonium sulphide, a white turbidity would indicate zinc, and, after the addition of solution FERRUM. of sodium phosphate, the formation of a white crystalline precipi- tate would indicate magnesium salts. Gum, starch, dextrin, sugar, and other carbohydrates may be detected by their carbonization, becoming brown or blackish, when a little of the ferrous lactate is strewn upon cold concen- trated sulphuric acid, and shaken therewith, and, if necessary, allowed to remain in contact for several hours; they may also be detected by boiling a saturated aqueous solution of the salt for a few minutes with a few drops of dilute sulphuric acid, and subse- quently neutralizing the solution with potassium or sodium hy- drate; the filtered liquid, upon the addition of a few drops of Fehling’s solution, and heating to boiling, will afford a precipitate of red cuprous oxide, if the above-mentioned carbohydrates be present. FERRI OXALAS. Oxalate of Iron. Ferrous Oxalate. FERRUM OXALICUM. Ger. Oxalsaures Eisenoxydul; Fr. Oxalate de fer ; Sp. Oxalato de liierro. FeC204 + II20 ; 161.9. A lemon-yellow, crystalline powder, permanent in the air; when strongly heated in contact with air, it decomposes with a faint combustion, and leaves a residue of red ferric oxide, amount- ing to 49.38 per cent, of its weight. Ferrous oxalate is almost insoluble in water, but readily soluble in hydrochloric acid, affording a solution, which, when largely diluted with water, produces a deep blue coloration upon the addition of a few drops of a solution of potassium ferricyanide. When boiled with a solution of sodium carbonate, filtered, the filtrate supersaturated with acetic acid, and solution of calcium chloride subsequently added, a white precipitate of calcium oxa- late will be produced. Examination: Ferrous oxalate, when ignited at a red heat, in a small porce- lain crucible, affords a residue which is neutral in its action upon litmus; and, if the ignited residue be extracted, with boiling- water and filtered, the filtrate should afford no residue upon evaporation. When a small portion of the salt is dissolved in hydrochloric acid, the solution diluted with water, filtered, and saturated with hydrogen sulphide, it should afford no dark color- ation (absence of foreign metals, lead, copper, etc.); the acid solu- tion warmed with a few drops of nitric acid, and subsequently completely precipitated by ammonia-water in excess, and filtered, 356 MANUAL OF CHEMICAL ANALYSIS. should afford a filtrate which is not rendered turbid upon the addition of ammonium sulphide (absence of zinc), and, when evap- orated and strongly heated, should become completely volatilized. FERRI OXIDUM HYDRATUM. FERRI PEROXIDUM HYDRATUM. FERRUM OXYDATUM. HYDRICUM FUSCUM. Hydrated Oxide of Iron. Peroxyhydrate of Iron. Ferric Hydrate. Ger. Eisenliydroxyd; Fr. Sesquioxyde de fer hydrate ; Sp. Hidrato de per- oxide de hierro. Fe2(HO)fi; 213.8. A reddish-brown, tasteless powder, destitute of grittiness, which, when heated in a dry test-tube, emits moisture, but no acid vapors. By exposure for several days to a temperature of 100° C. (212° F.), it forms a scarlet powder, having the compo- sition Fe407H2(2Fe203 + II20), and the specific gravity 4.4545, and, upon gentle ignition, is completely converted into red ferric oxide, Fe203. Ferric hydrate is slowly but wholly soluble in moderately dilute acids, even in acetic acid, without any considerable efferves- cence (a small amount of carbonic acid being absorbed by its exposure to the air); when dissolved in cold hydrochloric acid, the solution, after dilution with water, yields a blue precipitate with potassium ferrocyanide, but should not afford a blue coloration with potassium ferricyanide, and, upon saturation with hydrogen sulphide, but a white precipitate of sulphur should be produced. The acid solution, after complete precipitation by ammonia-water in excess, and subsequent filtration, should yield a colorless fil- trate, which affords no precipitate upon the subsequent addition of either ammonium sulphide, ammonium oxalate, or sodium phos- phate (evidence of the absence of zinc, calcium, and magnesium). Examination: Alkaline sulphates or chlorides may be detected by agitating the ferric hydrate with a little warm water, acidulating the filtrate with a few drops of nitric acid, and subsequently testing with barium chloride and argentic nitrate ; a white precipitate in either case will reveal the presence of such impurities, which may result from imperfect washing, in its preparation from ferric sulphate or chloride. Ammonia will be detecled by its odor, when a small portion of the ferric hydrate is gently heated, in a test-tube, with a concen- trated solution of potassium or sodium hydrate; and by the for- mation of white fumes, when a glass rod, moistened with acetic acid., is held over the mouth of the tube. FERRUM. 357 Copper may be detected by a blue coloration of ammonia-water or a solution of ammonium carbonate, when agitated with the ferric hydrate, and subsequently filtered ; its presence may be confirmed or recognized, when the result of the preceding test is uncertain, by supersaturing the filtrate with acetic acid, and test- ing it with potassium ferrocyanide; a reddish-brown precipitate would indicate or confirm the presence of copper. Other metallic impurities, if.present, will be indicated by the above-described characters and tests, and, when required, their nature may be determined, according to the systematic method of anatysis, as described on pages 51-61. FERRI PHOSPHAS.* FERRUM PHOSPHORICUM. FERRUM OXYDULATO-OXYDATUM PHOSPHORICUM. Phosphate of Iron. Ferrous Phosphate. Ger. Phospliorsaures Eisenoxydul; Fr. Phosphate de fer; Sp. Fosfato de hierro. A fine, amorphous, tasteless powder, of a slate-blue color when dry, but which, upon prolonged boiling with water, assumes a greenish color. When heated in a dry test-tube, it gives off water, and leaves a black residue. Ferrous phosphate is insoluble in water, but soluble in the mineral acids; with phosphoric acid it forms a clear, colorless solution, whilst its solution in hydrochloric acid, in consequence of the contained ferric salt, a result of superficial oxidation, pos- sesses a yellow color; the latter solution, when largely diluted with water, consequently yields a blue precipitate with both potassium ferricyanide and ferrocyanide, and, upon saturation with hydrogen sulphide, affords a slight white turbidity or opales- Fe3(P04)2+H20; 375.7. * The phosphate of iron (Ferri Phosphas) of the U. S. Pharmacopoeia is a mixture of ferric phosphate with sodium citrate, prepared by dissolving sodium phosphate in a solution of ferric citrate, evaporating the solution to the consistence of a thick syrup, and spreading it on plates of glass, so that, on drying, the salt maybe obtained in scales. It thus forms thin, transparent scales, of a bright green color, permanent in the air, but becoming dark on ex- posure to the light. It is readily aud completely soluble in water, but insoluble in alcohol. Its aqueous solution is neutral in its action upon litmus, yields a blue coloration with solution of potassium ferrocyanide, and, after acidulation with hydrochloric acid, a blue precipitate; when heated with an excess of a concen- trated solution of potassium hydrate, it yields a brownish-red precipitate of ferric hydrate, and the filtrate, after supersaturation with acetic acid, yields a light yellow precipitate with solution of argentic nitrate (distinction from ferric pyro- phosphate). The salt contains an amount of ferric phosphate corresponding to about 13.5 per cent, of metallic iron. MANUAL OF CHEMICAL ANALYSIS. eence, due to the separation of sulphur, but no dark coloration should be produced. When ferrous phosphate is boiled in a solution of sodium car- bonate, and filtered, a filtrate is obtained which, when exactly neutralized with dilute nitric acid, gives a yellow precipitate with argentic nitrate, and a white crystalline precipitate with magne- sium mixture, but, after acidulation with hydrochloric acid, should afford upon saturation with hydrogen sulphide, either in the cold or upon warming, no coloration or precipitate (a yellow turbidity would indicate the presence of arsenic). Examination: Sodium sulphate, left from insufficient washing, may be de- tected when a little of the powder is shaken with some hot water, and the filtrate tested with barium chloride. Metals.—A strong solution of the powder in hydrochloric acid, after dilution with water, is saturated with hydrogen sulphide, and set aside for a fbw hours, in a closed flask, in a warm place; Fig. 117. a slight white turbidity (sulphur) will occur; a dark coloration would indicate copper, a yellow one, arsenic, which latter, in con- nection with the above mentioned test, may be confirmed by the odor when a little of the salt is heated upon charcoal, before the FERRUM. 359 blow-pipe, or by the formation of a metallic mirror, in a narrow tube (Fig. 117), upon heating the dried precipitate with about six times its weight of a mixture of equal parts of exsiccated sodium carbonate and potassium cyanide. FERRI PYROPHOSPHAS. FERRUM PYROPHOSPHORICUM. Pyrophosphate of Iron. Ferric Pyrophosphate. Ger. Pyropliospliorsaures Eisenoxyd ; Fr. Pyrophosphate de fer ; Sp. Pirofosfato de hierro. Fe4(P207)3 + 9H20 ; 907.6. A white, tasteless powder, which, when heated in a dry test- tube, loses water and decreases in volume, but remains white. It is insoluble in water, but soluble in hydrochloric acid, and in solutions of sodium pyrophosphate and of alkaline citrates; its solution in dilute hydrochloric acid has a yellowish color, and affords a blue precipitate with potassium ferrocyanide, and, upon saturation with hydrogen sulphide, a white turbidity, due to the separation of sulphur, but no dark coloration is produced. When boiled with a solution of sodium carbonate, ferric pyrophosphate assumes a reddish brown color, and yields a filtrate of the same tint, but which becomes almost decolorized upon slight super- saturation with acetic acid, and gives a dense, white precipitate with argentic nitrate (distinction from ferric orthophosphate, which gives a yellow precipitate, and from ferric metaphosphate, which gives a white gelatinous one). FERRI PYROPHOSPHAS ET SODII CITRAS. Pyrophosphate of Iron with Gitrate of Sodium. Pyrophosphate of Iron in Scales. FERRUM PYROPHOSPHORICUM CUM NATRIO CITRICO. Ger. Pyropliosphorsaures Eisenoxyd rait citronensaurera Natrium; Fr. Pyro- phosphate de fer et citrate de soude ; Sp. Pirofosfato de hierro y citrato de sodio. Thin, apple-green, transparent scales, of a mild, acidulous, and slightly saline taste, and permanent in dry air ; by exposure to the light the scales lose their transparency and become darker in color. The salt is freely and completely soluble in twice its weight of water, and is also soluble in glycerin, but insoluble in alcohol. MANUAL OF CHEMICAL ANALYSIS. The dilute aqueous solution is of a bright yellow color, almost tasteless, and neutral in its action upon litmus; it is not precipi- tated bv ammonia-water, but assumes with the latter a brown coloration, and when heated with solution of potassium hydrate, in slight excess, yields a red-brown precipitate of ferric hydrate; if the iron be thus completely precipitated from the solution, fil- tered, the filtrate supersaturated with acetic acid, and a few drops of solution of argentic nitrate subsequently added, a white pre- cipitate will be produced (distinction from ferric phosphate). The solution affords a blue coloration with solution of potassium ferrocyanide, and, after acidulation with hydrochloric acid, a blue precipitate is produced; when mixed with hydrogen sulphide- water, no immediate change is produced, but the mixture soon assumes a black color. The dry salt should neither produce effervescence nor a dark coloration when strewn upon cold, concentrated sulphuric acid (absence of carbonates and of foreign organic substances). It contains an amount of ferric pyrophosphate corresponding to about 11.5 per cent, of metallic iron. FERRI SUBCARBONAS. FERRUM CARBONICUM. FERRUM SUB-CARBONICUM. Carbonate of Iron. Basie Ferrous Carbonate. Get-. Kolilensaures Eisenoxydul; Fr. Sous-carbonate de fer; Sp. Carbonate de liierro. A fine, amorphous, reddish-brown powder, without odor or taste, which, in consequence of the absorption of oxygen and the elimina- tion of carbonic acid gas, consists for the most part of ferric hydrate (page 356), with small and varying amounts of ferrous carbonate. When gently heated in a dry test-tube, it emits aqueous vapors, which condense in the cooler parts of the tube, and which, when tested with blue litmus-paper, should not alter its color ; upon more strongly heating, it is completely converted into red ferric oxide, Fe203. Carbonate of iron is insoluble in water, but readily and freely soluble, with slight effervescence, in warm, diluted hydrochloric acid, forming a yellow solution, a few drops of which, when added to water, impart to this the property of yielding a blue precipi- tate with both potassium ferrocyanide and ferricjmnide. The solution therefore affords, with reagents, the reactions of both ferrous and ferric salts. Examination: Ferri Subcarbonas is distinguished from Ferri Oxidum Hy- dratum by its readier solubility in hydrochloric acid, accompanied FERRUM. 361 by active effervescence, and affording a yellow solution, which, when largely diluted with water, yields a blue precipitate with both potassium ferrocyanide and ferricyanide. Alkaline sulphates may be detected by agitating a small portion of the powder, in a test-tube, with a little warm water, and sub- sequently filtering; the filtrate should leave no considerable residue upon evaporation on platinum-foil, nor, when acidulated with a few drops of nitric acid, should it yield a white turbidity upon the addition of barium chloride. Metals.—A small portion of the powder is dissolved in dilute hydrochloric acid, the solution boiled with a few drops of nitric acid, and subsequently precipitated by ammonia-water in slight ex- cess, and filtered; a blue coloration of the filtrate will reveal the presence of copper, and a white precipitate upon the addition of a few drops of ammonium sulphide will indicate the presence of zinc. FERRUM SULFURICUM. FERRI SULPHAS. Sulphate of Iron. Ferrous Sulphate. Ger. Scliwefelsaures Eisenoxydul (Eisenvitriol) ; Fr. Sulfate de fer ; Sp. Sulfato de hierro. FeS04+ 741,0; 277.9. Transparent, pale bluish-green, monoclinic prisms (Fig. 118), of the specific gravity 1.889, or, when obtained by precipitation, by means of alcohol, a pale bluish-green, crystal- line powder (Ferri Sulphas Pre&cipitatus). The crystals are slowly efflorescent in dry air, and by exposure to a moist atmosphere rapidly absorb oxygen, becoming coated with a layer of brownish-yellow, basic ferric sulphate ; they contain seven molecules (45.82 per cent.) of water of crystallization, six-sevenths of which they lose at a moderate heat, leaving a green- ish or grayish white powder (Ferri Sulphas Exsiccatus). At a red heat, the seventh mole- cule of water, and also the acid is expelled, leaving behind red, anhydrous ferric oxide (Caput Mortuum). Ferrous sulphate is soluble in 1.8 parts of water at 15° C. (59° F.), in 0.3 part of boiling water, and is slightly soluble in diluted, but insoluble in absolute, alcohol; its aqueous solution has a greenish-blue color, an unpleasant styptic taste, and a slightly acid reaction ; it readily absorbs oxygen, acquiring a yel- Fig. 118. 362 MANUAL OF CHEMICAL ANALYSIS. low color, and becomes turbid by the formation of an insoluble basic ferric sulphate, while a neutral ferric sulphate remains in solution, with the undecomposed ferrous sulphate. The solution of ferrous sulphate, when largely diluted, gives a white precipi- tate with barium chloride, a blue one with potassium ferricyanide, and, when not yet oxidized, a white one with the ferrocyanide, but. after acidulation with hydrochloric acid, affords no precipi- tate upon saturation with hydrogen sulphide. Examination: Metals.—’A small portion of the salt is dissolved in about twice its weight of water, the solution acidulated with a few drops of hydrochloric acid, and subsequently saturated with hydrogen sul- phide ; no precipitate, or but a white turbidity (sulphur) should be formed; a dark turbidity would indicate copper, and perhaps other metals. The liquid is then filtered, evaporated in a porce- lain capsule until deprived of odor, subsequently boiled with a few drops of concentrated nitric acid, and finally completely pre- cipitated by ammonia-water, in considerable excess, and filtered. The filtrate is subsequently tested with ammonium sulphide; an ensuing white turbidity would indicate zinc, a reddish-white one, manganese. Finally, the liquid, after having been filtered, if such reactions have occurred, is tested with ammonium phosphate; a crystalline, white precipitate, occurring after some time, would indicate magnesium. Crude commercial sulphate of iron is generally considerably contaminated with metallic and earthy salts, and not fit for medici- nal use; it frequently contains the sulphates of zinc, aluminium, and magnesium, and generally so much sulphate of copper as to deposit a metallic cupreous film upon a bright blade of an iron knife or spatula, when immersed for some hours in the aqueous solution, acidulated with a few drops of sulphuric acid, and may also contain arsenic. Estimation: The purity of ferrous sulphate, as based upon the estimation of the equivalent percentage amount of the therein contained metallic iron, may be readily and very accurately determined volumetrically. About one gram of air-dry and uneffioresced crystals of the salt is accurately weighed, and dissolved, in a beaker, in about 200 cubic centimeters of water, the solution subsequently acidulated with dilute sulphuric acid, and a stand- ard solution of potassium permanganate (page 89) allowed to flow into the liquid from a burette until, with constant stirring, the pink tint of the liquid remains for a time unchanged. The factor of the permanganate solution having been previously ascer- tained (see pages 89-90), and the number of cubic centimeters of the solution required for the complete oxidation of the ferrous to ferric salt, as above described, being known, a simple calculation will determine the amount of iron contained in the ferrous state FERRUM. in the salt, or the percentage amount of pure, crystallized ferrous sulphate. Another method consists in dissolving 4.167 grams of the salt in water acidulated with diluted sulphuric acid, and allowing a standard solution of potassium bichromate (page 91) to flow into the liquid, until a drop removed by means of a glass rod, and placed on a porcelain plate, no longer gives a blue color with solution of potassium ferricyanide; the number of cubic cen- timeters of potassium bichromate solution thus required, when multiplied by 2, will represent the percentage amount of unoxi- dized, crystallized ferrous sulphate. Table of the percentage strength of solutions of crystallized Ferrous Sulphate (FeS04+ 711/)) of different specific gravities ( Gerlach). Temperature 15° 0. (59° F.). Specific gravity. Per cent, of FeS044-7H20. Specific gravity. Per cent, of ] FeS04+7H20. , Specific gravity. Per cent, of FeS04-f7H20. 1.005 1 1.077 14 1.155 27 1.011 2 1.082 15 1.161 28 1.016 3 1.088 16 1.168 29 1.021 4 1.094 17 1.174 30 1.027 5 1.100 18 1.180 31 1.032 6 1.106 19 1.187 32 1.037 7 1.112 20 1.193 33 1.043 8 1.118 21 1.200 34 1.048 9 1.125 22 1.206 35 1.054 10 1.131 23 1.213 36 1.059 11 1.137 24 1.219 37 1.065 12 1.143 25 1.226 38 1.071 13 1.149 26 i\ 1.232 39 FERRI VALERI ANAS. FERRUM VALERIANICUM. Valerianate of Iron. Ferric Valerianate. Ger. Baldriansaures Eisenoxyd ; Fr.Valerinate de fer; Sp.Valerianato de liierro. A dark, brick-red, amorphous powder, permanent in dry air, and possessing the odor of valerianic acid. When gently heated, the salt loses its acid without fusing, but when rapidly heated in a porcelain capsule, it fuses, emits inflammable vapors, and, when incinerated, leaves behind ferric oxide, which should not color moistened turmeric-paper brown, nor dissolve in warm dilute acetic acid. Fea(CaH902)6,Fe2(0H)6; 981.6. Ferric valerianate is insoluble in water, and is only miscible therewith after having been previously moistened with a little MANUAL OF CHEMICAL ANALYSIS. alcohol; boiling water decomposes it, extracting the valerianic acid, and affording a colorless filtrate, which reddens litmus-paper, but does not become turbid upon the addition of ammonia-water, either before or after saturation with hydrogen sulphide. Acids decompose ferric valerianate, forming soluble ferric salts, and setting free the valerianic acid. The so-called soluble valerianate of iron (Ferrum valerianicum solubile) occurs in thin, reddish scales, and consists of neutral or normal ferric valerianate, Fe2(CsH902)6 -f- 10II2O; it is likewise insoluble in water, but is soluble in alcohol (distinction from ferric citrate aud tartrate), and exhibits the same behavior by the action of heat or boiling water as the above-described preparation, leav- ing, however, a much less considerable residue upon ignition. Examination: Admixtures of ferric tartrate or citrate, impregnated with oil of valerian or valerianic acid, may readily be recognized by their solubility in water and insolubility in strong alcohol; the latter dissolving the oil of valerian, or valerianic acid, if such be pres- ent, which may be readily recognized by the odor, when a portion of the alcohol is evaporated upon the warm hand, while a residue will remain, responding to the tests of ferric citrate or tartrate, as described on pages 343 and 347, if such admixtures be present. FERRUM. Iron. Ger. Eisen ; Fr. Fer ; Sp. Hierro. Fe; 55.9. The source of the medicinal preparations of iron is the refined malleable wrought iron, of which the piano-forte wire is among the best commercial varieties. When iron filings or turnings are employed instead .of wire, care has to be taken that they are not derived from crude cast or pig iron, that they are free from rust, and that they are not contaminated with copper or brass filings from the workshops. Cast or pig iron may be recognized by the evolution of gas of a noxious odor, and by a considerable black residue, when the filings or turnings are dissolved, in a test-tube, in a mixture of equal parts of concentrated hydrochloric acid and water. An admixture of copper or brass filings may be recog- nized, with approximate certainty, by close inspection, with a magnifying-glass, and by chemical tests, as hereafter described. In the preparation of solutions of iron, which are subsequently filtered, filings of cast iron are not exactly objectionable; iron filings or turnings, however, which may contain, or are liable to contain, copper or brass filings, ought not to be employed for FERRUM. 365 medicinal preparations, since copper is dissolved by boiling with an excess of acid, notwithstanding the predominating presence of iron. Ferrum Pulveratum.—A fine, gray powder, of a dull, metal- lic appearance, and having the specific gravity 7.78; when strongly heated, with exposure to the air, it becomes oxidized to black ferroso-ferric oxide, and increasing in weight, if the powder em- ployed was pure and dry. Iron powder dissolves in a mixture of equal parts of hydrochloric acid and water, evolving impure hydrogen gas, of a faint odor, and leaving only a small insoluble black residue; the filtered solution has a light-green color, and affords, when largely diluted with water, a deep-blue turbidity with potassium ferricyanide, and almost white precipitates with the alkaline hydrates and carbonates, which, however, rapidly oxidize, and become green, and ultimately brown. Examination: Sulphur, phosphorus, and arsenic, may be detected, in iron pow- der, filings, turnings, or wire, by the odor of the evolved gas, when dissolved in dilute hydrochloric or sulphuric acid, and by testing the gas thus evolved, either with a strip of paper moistened with a solution of plumbic acetate and placed over the mouth of the tube, or by loosely inserting a cork pro- vided with two strips of paper, one of which is moistened with a solution of plumbic acetate, and the other with a solution of argentic nitrate (Fig. 119); the blackening of both the lead and silver paper will indicate the presence of sul- phur, whilst a blackening of the silver paper alone may arise from the presence of either phosphorus or arsenic. The presence of sulphur may be confirmed by dissolving a portion of the iron in dilute nitric acid, and testing the solution with bari- um nitrate; a white precipitate of barium sulphate will be produced if sulphur were pre- sent. The presence of arsenic, if indicated by the above test, may also be confirmed by the application of Marsh's test, as described on pages 38 to 36. Phosphorus also be detected by dissolv- ing a portion of the iron in warm dilute hydro- chloric acid, boiling the solution with a few drops of concentrated nitric acid, and filtering, wdiereby any carbonaceous or siliceous matter will remain prin- cipally undissolved, and may be further examined. The solution is then evaporated to remove the excess of acid, diluted with water, again filtered, if necessary, and incompletely precipitated Fig. 119. 366 MANUAL OF CHEMICAL ANALYSIS. with sodium carbonate, avoiding an excess of the latter. The pre- cipitate of ferric hydrate thus obtained (containing the phos- phoric acid) is filtered off, dried, mixed with about four times its weight of exsiccated sodium carbonate, and ignited in a small porcelain crucible. The fused mass is then digested with hot water, the solution filtered, acidulated with hydrochloric acid, and magnesium mixture subsequently added; the formation of a white crystalline precipitate will reveal the presence of phos- phorus, which, by the above treatment, is converted into phosphoric acid. Metallic Impurities.—A portion of the iron is dissolved in dilute hydrochloric acid, the solution boiled with a few drops of con- centrated nitric acid, and subsequently completely precipitated by ammonia-water, in excess, and filtered. The filtered solution should afford no turbidity upon the addition of ammonium sul- phide ; a blue coloration of the ammoniacal liquid will reveal the presence of copper, whilst a black precipitate with the last-named reagent may indicate copper, cobalt, or nickel, a flesh-colored pre- cipitate, manganese, and a white precipitate, zinc. Copper, zinc, and lead may also be detected, even when pre- sent in very small amount, by dissolving a portion of the iron in an excess of warm concentrated hydrochloric acid, filtering, if necessary, and cautiously pouring upon the acid solution a satu- rated aqueous solution of hydrogen sulphide; the presence of copper and lead will then be indicated by a brown zone be- low the line of contact of the two liquids, and as zinc, when present, is usually contained in the form of brass, the confirma- tion of a contamination with copper would of itself render the iron objectionable. Lead may be specially sought for, when de- sired, by adding to the solution of the iron in hydrochloric acid a few drops of sulphuric acid, then ammonia-water in slight excess, agitating the mixture, and subsequently adding four or five times its volume of dilute sulphuric acid, and again agitating well; the presence of the smallest amount of lead will thus be indicated by an opalescence, dependent upon the separation of plumbic sulphate. Black oxide of iron (ferroso-ferric oxide) and organic matter, occurring as a contamination of powdered iron, may be detected in the first instance by its much less ready solubility in a mixture of bromine and water, and, in the second instance, by the ignition of the powder in a small glass tube. Estimation: The estimation of the purity of metallic iron, when free from oxide, may be readily accomplished volumetrically, by dissolving about 0.2 gram of the substance in a small flask, so arranged as to prevent the oxidation of the iron during solution (Fig. 120), in about 20 cubic centimeters of dilute sulphuric acid, pouring the solution, when cool, together with the rinsings of the flask, into FERRUM. a beaker, diluting with water to about 100 cubic centimeters, and finally allowing a standard decinormal solution of potassium permanganate (page 89) to flow into the liquid from a burette until, with constant stirring, the pink tint of the liquid remains for a time unchanged. The factor of the permanganate solution having been pre- viously ascertained (see pages 89-90), and the number of cubic centimeters of the solu- tion required to produce the above result, or to effect the complete oxidation of the iron, being known, a simple calculation will deter- mine the amount of pure metallic iron con- tained in the specimen under examination. Ferrum Beductum (Ferrum Hydrogenio Keductum).—Iron powder, obtained by the reduction of ferric oxide or hydroxide, or ferrous oxalate, by means of hydrogen, at a strong heat, forms a very fine, gray, loose, lustreless powder, which, when strongly heated, with exposure to the air, becomes oxidized to black ferroso-ferric oxide; when touched with a lighted taper it ignites and burns, affording likewise, as a product of combustion, black ferroso ferric oxide. Beduced iron is readily and wholly soluble in warm diluted hydrochloric acid, with the evolution of pure hydrogen gas, which is without action upon paper moistened with a solution of plumbic acetate or argentic nitrate, and forming a solution which has the same properties and deportment with reagents as that of powdered iron. If the solution takes place without a copious evolution of gas, and has, when filtered, a yellowish appearance instead of a light- green one, the powder was more or less oxidized, or even so much so as to consist almost wholly of a mix- ture of ferrous and ferric oxides. Examination of Ferrum Reductum: In addition to the above-detailed characters, re- duced iron should respond to the following test: When digested for half an hour, at ordinary temperatures, with 25 times its weight of a solution of ferric chlo- ride, of the specific gravity 1.3, in a glass cylinder provided with a glass stopper (Fig. 121), the mixture being repeatedly shaken, the iron should become com- pletely dissolved; any insoluble residue (which may consist of the oxides of iron or other foreign sub- stances) will, according to its amount, determine ap- proximately the value of the specimen under exami- nation. Another test, which may be applied to the determin- Fig. 120. Fig. 121. 368 MANUAL OF CHEMICAL ANALYSTS. ation of the presence of a definite minimum amount of metallic iron in the preparation, consists in digesting for two hours, in a glass vessel, 0.5 part of ferrum reductum with a solution of 1.18 parts of iodine and 1.2 parts of potassium iodide in 25 parts of water; if the solution, at the expiration of two hours, and with the em- ployment of the above proportions, contains no free iodine, but is clear and of a pale greenish color, the presence of at least 50 per cent, of metallic iron in the preparation is assured. The same test may readily be extended in its requirements by the applica- tion, in the employment of 0.5 part of ferrum reductum, of 0.226 additional part of iodine, with the proper proportionate amount of potassium iodide, for each 10 per cent, of metallic iron to be indicated. The United States Pharmacopoeia directs that if 1 gram of reduced iron be digested with 8.5 grams of iodine, 2.5 grams of potassium iodide, and 50 cubic centimeters of distilled water, for two hours, the resulting filtrate should have a green color, and should not be rendered blue by gelatinized starch (corresponding to the presence of at least 80 per cent, of metallic iron). The further testing of ferrrum reductum for sulphur, phos- phorus, arsenic, metallic impurities, or other admixtures which may be likely to occur, or are otherwise indicated, may be per- formed according to the methods described under ferrum pul- veratum, on pages 865-366. Estimation of"Ferrum Reductum: I. A convenient and simple method for the estimation of the amount of pure metallic iron in ferrum reductum, and which pro-, vides for its admixture with ferroso-ferric oxide, Fe304, but not for the other oxides or their combinations, is as follows: About 0.2 to 0.3 gram of ferrum reductum, accurately weighed, together with a little pure zinc (about 1 gram), are dissolved in about 20 cubic centimeters of dilute sulphuric acid, in a small flask, so arranged as to prevent the oxidation of the iron during solution (Fig. 120. page 367). The solution, after being allowed to cool, is transferred to a beaker, and, together with the rinsings of the flask, diluted to the measure of 100 cubic centimeters; a standard decinormal solution of potassium permanganate (page 89) is then allowed to flow into the liquid from a burette until, with con- stant stirring, the pink tint of the liquid remains for a time unchanged. The factor of the permanganate solution having been previously ascertained (pages 89-90), the number of cubic centimeters of the solution employed will indicate, by simple cal- culation, the total amount of iron present, from which the per- centage amount of the latter may be determined. In consideration, however, that the entire amount of iron determined was not originally present as metallic iron, but associated in part with fer- roso-ferric oxide, Fe304, which becomes reduced to ferrous salt through the agency of the nascent hydrogen, the number 72.4 FERRUM. 369 should be subtracted from the total percentage of iron, and the remainder divided by the decimal 0.276, which will yield, as the quotient, the percentage of pure metallic iron contained in the specimen under examination. II. Another method, which is based upon the determination of the amount of metallic copper precipitated by a definite amount of reduced iron from a solution of cupric sulphate of known strength, and which requires no correction, as in the above method, for the presence of ferrous or ferric oxides, is as follows: 1 gram of the reduced iron is digested for one hour with a solution of 5 grams of pure cupric sulphate in 25 grams of water, acidulated with 2 drops of dilute sulphuric acid; the solution is then filtered into a previously weighed flask, the filter washed with sufficient distilled water to obtain 50 grams of filtrate, 1 gram of pure pow- dered iron (the percentage of carbon contained in it should be previously determined) added, and the whole digested until the copper contained in the solution is completely precipitated in a metallic state; 5 grams of pure concentrated sulphuric acid are subsequently added, and the mixture gently heated until the iron is completely dissolved, when the precipitated copper will alone remain, contaminated with a little carbon. The copper is re- peatedly washed, by decantation, first with water, afterwards with alcohol, and finally with absolute alcohol and ether; the flask is then quickly dried, by the aid of a gentle heat, weighed, and from the weight of the copper the carbon of the powdered iron (about 0.01 gram) subtracted. Since the difference between the weight of this precipitated copper and the total weight of the metallic copper (1.271 gram) contained in the 5 grams of crystallized sul- phate equals the quantity of copper which was precipitated by the metallic iron contained in 1 gram of the reduced iron, the percentage of the unoxidized metal is readily determined from the ascertained weight, and the relation between the atomic weights of copper and iron. The number of centigrams of iron, calculated from the copper which was precipitated in the first part of the process, indicates directly the percentage of metallic iron contained in the reduced iron. 370 MANUAL OF CHEMICAL ANALYSIS. GLYCERINUM. GLYCERINA. Glycerin. Triatomic Propenyl Alcohol. Ger. Glycerin ; Fr. Glycerine; Sp. Glicerina. C3H803 - C3H5(OH)3l or CH2-OH CH-OH ; CH2-OPI 92. A colorless and odorless, thick, viscid, neutral liquid, of an intensely sweet taste; when anhydrous, its spec. grav. is 1.267 at 15° C. (59° F.); that of commercial glycerin, containing from 5 to 10 per cent, of water, is from 1.25 to 1.237. When perfectly anhydrous, and exposed to a temperature of 0° C. (32° F.), it is capable, under certain conditions, of assuming the crystalline form; the crystals have a specific gravity of 1.262, belong to the rhombic system, and attract moisture with great avidity, becom- ing finally liquefied at 10° C. (50° F.), while the melting-point ot the perfectly anhydrous crystals is apparently above 23° C. (73.4° F.). Glycerin is not volatile at common temperatures, but, when ex- posed in thin layers, is perceptibly volatilized at a temperature of 100° C. (212° F.), and distils unchanged in vacuo, or with aqueous vapor, under pressure; it boils, under ordinary atmo- spheric pressure, at 290° C. (554° F.), undergoing partial decom- position, and emitting white, irritating, inflammable vapors, which, when ignited, burn with a pale blue flame, leaving no residue. Glycerin is miscible, in all proportions, with water, solutions of the alkaline hydrates, alcohol, and ether diluted with alcohol, but not with pure ether, chloroform, carbon bisulphide, or benzol; it mixes with concentrated sulphuric acid, with the formation of sul- pho-glyceric acid, Qpj , which affords soluble salts with the oxides of barium, calcium, and lead; with concentrated nitric and hydrochloric acids, it suffers decomposition, becoming either oxidized, or forming therewith compound ethers, as in the case of the powerfully explosive, so-called nitroglycerin, C3H5(0-N02)r When heated with dehydrating substances (con- centrated sulphuric or phosphoric acid, or acid potassium sul- phate), glycerin is converted into the strongly irritating substance, acrolein) C3H40. Glycerin possesses extensive powers as a solvent; it dissolves most substances which are soluble in water, although usually in a less degree, but, in some instances, is a better solvent, as, for instance, in the case of alum, borax, and carbolic acid; and dis- solves readily many substances which are insoluble or very spar- GLTCERINUM. ingly soluble in water, such as sulphur and mercuric iodides, bro- mine, iodine, quinine, morphine, and other alkaloids, as also many metallic oxides, and prevents the precipitation of the latter from their solutions by the alkaline hydrates. It does not mix with fatty oils, and dissolves essential oils only to a limited extent. Examination: A fatty or empyreumatic odor of glycerin is best recognized by gently warming a little of the sample on a watch-glass, or in a small porcelain capsule, or by the addition of a little dilute sul- phuric acid. Cane-sugar, glucose, and mucilages are indicated by a more or less brown coloration of the glycerin, when mixed with twice its volume of concentrated sulphuric acid, or when mixed and heated with a strong solution of potassium hydrate; they will also be indicated by a considerable carbonaceous residue, when a little of the glycerin is heated to boiling, in a small platinum capsule, and the vapors ignited. Glucose may be detected by the occurrence of a brick-red pre- cipitate, when a little of the glycerin, diluted with an equal volume of water, is heated with a few drops of an alkaline solu- tion of cupric tartrate. Cane-sugar is detected by the same reaction, when the glycerin is boiled for a few minutes with an equal volume of dilute solu- tion of tartaric acid, and the hot mixture tested with Fehlmg’s cupric solution. Mucilages of gum, dextrin, or glue are indicated by the forma- tion of a white turbidity, gelatinous or flocculent, when one volume of the glycerin is mixed with four volumes of alcohol. Metallic salts are detected by agitating one volume of the glycerin with three volumes of a saturated aqueous solution of hydrogen sulphide; any impairment of the colorlessness or transparency of the mixture would indicate metallic impurities; they may be dis- tinguished, as to the group of metals to which they belong, by divid- ing the liquid into two portions, and adding to the one a little hydrochloric acid, and to the other ammonia-water. Copper, lead, and tin will be indicated by the first test; iron, zinc, and alu- minium, by the second. If a precipitate appears in either case, and the nature of the impuritj- has to be ascertained, the test must be repeated on a larger scale, and the metallic impurity deter- mined by the methods described on pages 51 to 59. Calcium salts may be detected in the diluted glycerin, by a white turbidity when tested with ammonium oxalate. Ammonium salts, occasioned by the neutralization of an origi- nally slightly acidulous glycerin with ammonia-water, may be detected by the odor of ammonia when the glycer.n is heated, in a test-tube, with unequal volume of a concentrated solution of po- tassium hydrate, and by the appearance of white fumes, when a 372 MANUAL OF CHEMICAL ANALYSIS. glass rod, moistened with acetic acid, is held over the mouth of the tube. Acids and their Salts.—When diluted with twice its volume of water, the solution must leave litmus-paper unchanged ; it is then examined in four separate portions: for hydrochloric acid and chlorides, by acidulating with nitric acid, and testing with argentic nitrate; for sulphuric acid and sulphates, by testing the second portion, also acidulated with nitric acid, with barium nitrate; for oxalic acid, by testing the third portion, acidulated with acetic acid, with calcium acetate or chloride; and for nitric acid and nitrates, by adding to the fourth portion a little acetic acid and one drop of neutral indigo solution, and then warming the mix- ture by dipping the test-tube into hot water; a decoloration of the bluish or bluish-green tint of the liquid will indicate free nitric acid ; when the color remains unaltered, a few drops of con- centrated sulphuric acid are added to the mixture while still warm ; if decoloration takes place now (and the glycerin is free from chlorates), nitrates are indicated. Another very sensitive test for nitric acid and nitrates, com- bining the test for chlorine, is to mix, in a test-tube, a little muci- lage of starch with a few drops of solution of potassium iodide (free from iodate), and a few drops of dilute sulphuric acid, and then to add a small portion of glycerin; when mixed together with a glass rod, the liquid must remain colorless ; a blue color would indicate chlorine ; when the mixture remains colorless, a thin rod of bright zinc is immersed in the centre of the fluid, with care not to agitate the test-tube; if traces of nitric acid or nitrates be present, a bluish coloration, issuing from the zinc, will appear. Formic acid may be detected by the formation of a black de- posit, when a mixture of the glycerin with an equal volume of diluted ammonia-water and a little solution of argentic nitrate is allowed to stand in a corked test-tube, protected from the light, for twenty-four hours. Butyric acid, and analogous fatty acids, will be indicated by an acid reaction of the glycerin, and may be extracted therefrom by agitation with ether, or may be recognized by the odor of ethyl butyrate (similar to that of artificial essence of pine-apple), when a mixture of two volumes of gljmerin with one volume of a mix- ture of equal parts, by volume, of strong alcohol and concentrated sulphuric acid, is gently warmed by dipping the flask or test-tube into boiling water. Estimation of Glycerin in Wine, Beer, etc.: The separation and approximate estimation of glycerin in wine, beer, and other similar liquids, may be accomplished by treating the residue obtained by the evaporation of a measured portion of the liquid, in a small glass flask, with a warm mixture of 1 part of ether and 3 parts of alcohol, which extracts the glycerin, together with some succinic acid and sugar. The liquid is then HYDRARGYRUM. 373 filtered, if necessary, the filtrate neutralized with milk of lime, the alcohol removed by distillation or evaporation, and the dry residue again extracted with a warm mixture of ether and alcohol, which, after filtration, is allowed to evaporate, upon the water- bath, at the lowest possible temperature. The residue of glycerin thus obtained, after being allowed to stand for two days over sulphuric acid, is finally weighed. The glycerin may be subse- quently tested for its identity, if desired, by rendering it slightly alkaline with a dilute solution of sodium hydrate, and moisten- ing therewith a fused bead of borax, contained on the looped end of a platinum-wire: if the borax bead be subsequently held in a non-luminous flame, a deep green tint will be imparted to the latter. Table of the quantity by weight of Water contained in 100 parts by weight of Glycerin of different specific gravities. Temperature 17.5° C. (63.5° F.). Specific gravity. Per cent, of water. Specific gravity. Per cent, of water. Specific gravity. Per cent, of water. Specific gravity.. Per cent, of water. 1.267 0 1.224 13 1.185 26 1.147 39 1.264 1 1.221 14 1.182 27 1.145 40 1.260 2 1.218 15 1.179 28 1.142 41 1.257 3 1.215 16 1.176 29 1.139 42 1.254 4 1.212 17 1.173 30 1.136 43 1.250 5 1.209 18 1.170 31 1.134 44 1.247 6 1.206 19 1.167 32 1.131 45 1.244 7 1.203 • 20 1.164 33 1.128 46 1.240 8 1.200 21 1.161 34 1.126 47 1.237 9 1.197 22 1.159 35 1.123 48 1.284 10 1.194 23 1.156 36 1.120 49 1.231 11 1.191 24 1.153 37 1.118 50 1.228 12 1.188 25 1.150 38 HYDRARGYRI CHLORIDUM CORROSIVUM. HYDRARGYRI PERCHLORIDUM. HYDRARGYRUM BICHLORA- TUM. HYDRARGYRUM CORROSIYUM SUBLIMATUM. Corrosive Sublimate. Corrosive chloride, Perchloride, or Bichloride of Mer- cury. Mercuric Chloride. Ger. Quecksilberchlorid ; Fr. Bichlorure de mercure ; Sp. Bicloruro de mercurio. HgCl2; 270.5. Colorless, translucent, heavy, crystalline masses, when obtained by sublimation, or small, well-developed rhombic prisms (Fig. 122), when obtained by crystallization from its solutions, and having 374 manual of chemical analysis. a spec fie gravity of 5.403 ; they are permanent in the air, give a dull, white streak when scratched with a knife, fuse at 265° C. (509° F.), and volatilize wholly at 295° C. (563° F.), forming dense, white vapors, which, on cooling, solidify in small, shin- ing needles. Mercuric chloride is soluble in water, requiring, at 10° C. (50° F.), 15.22 parts, at 20° O. (68° F.), 13.53 parts, at 50° C. (122° F.), 8.81 parts, at 80° C. (176° F.), 4.11 parts, and at 100° C. (212° F.), 1.85 parts of water for solution; it is less soluble in glycerin, 100 parts of which dissolve about 7 parts of the salt, but is freely soluble in alcohol and ether, re- quiring, at 17° C. (62.6° F.), 2.5 parts of alcohol, spec. grav. 0.830, and 4 parts of ether for solution, and is abstracted, for the most part, by the latter, when agitated with its aqueous solution. The aqueous solu- tion reddens blue litmus-paper, and has an acrid, metallic, styptic taste ; upon the evaporation of the solution, by the aid of heat, a portion of the salt becomes volatilized with the aqueous vapors. In the aqueous solution of mercuric chloride, the fixed alkaline and earthy hydrates and alkaline carbonates produce, when added in small quantity, a reddish-brown precipitate; when added in excess, a yellow one ; ammonia-water gives a white one ; argentic nitrate, a curdy white one ; iodides, when added in small quan- tity, a yellowish, and in larger quantity, a vermilion-red one, sol- uble in an excess of the precipitant; stannous chloride, when added in small quantity, a white, and when added in excess, a gray pre- cipitate. When an aqueous solution of hydrogen sulphide is gradually added to a solution of mercuric chloride, the precipita- tion takes place according to the proportions of the reagent and the chloride, in progressive variation of color from white to yel- low, orange, reddish brown, and black; an excess of the reagent produces at once a complete black precipitation. When the aque- ous solution of mercuric chloride is rubbed upon bright copper, it coats the latter with a brilliant metallic film. It forms white, insoluble or sparingly soluble compounds with many organic substances, as albumen, fibrin, gluten, etc.; and by exposure to the light, particularly when in contact with organic substances and when possessing an alkaline reaction, it becomes gradually reduced to mercurous chloride (calomel), while its decomposition is prevented or materially retarded by the presence of hydrochloric acid or alkaline chlorides. Mercuric chloride is soluble, without decomposition, in nitric, hydrochloric, and sulphuric acids; and crystallizes from the solu- tions on cooling, if they were saturated while hot. With the alka- Fig. 122. HYDRARGYRUM. 375 line chlorides it combines to form double salts, which are mostly well crystallizable, and more readily soluble in water than mer- curic chloride. Examination; The purity of mercuric chloride will, in most instances, be suf- ficiently established by its conformity with the above described physical properties, by its complete volatilization upon strongly heating, and its relation to solvents, as also by the several chemical tests. Arsenic may be readily detected by digesting the powdered mercuric chloride with ammonia-water, or precipitating its aqueous solution by the latter, subse- quently filtering, and, after acidulating with dilute sulphuric acid, testing in Marsh’s apparatus, page 34; or, after the concentration of the solution by evapora- tion, the several tests for arsenious acid may be ap- plied, as described under the latter, on pages 127 to 130. The presence of arsenic may also be quickly deter- mined by dissolving a small portion of the salt in hot water, and adding to the solution, contained in a long test-tube, an excess of a concentrated solu- tion of sodium hydrate, and a few fragments of alumi- nium wire or pure zinc; a cap of bibulous paper, moistened with a drop of solution of argentic nitrate, is then placed over the orifice of the tube (F.g. 123), and the mixture gently heated ; an ensuing dark coloration of the paper or the production of a dark metallic stain will reveal the presence of arsenic. Mercurous chloride (calomel) and other insoluble im- purities or admixtures, will be detected by their re- maining undissolved, when the mercuric chloride is digested or gently warmed with about twenty times its weight of water. Fig. 123. HYDRARGYRI CHLORIDUM MITE. HYDRARGYRI SUBCHLORIDUM. HYDRARGYRUM CHLORATUM. MERCURIUS DULCIS. Calomel. Mild chloride, Sub- or Proto-chloride of Mercury. Mercurous Chloride. Ger. Quecksilberchloriir ; Fr. Protoclilorure de mercure ; Sp. Protocloruro de mercurio. Mercurous chloride varies in the minuteness of its particles, and accordingly in its appearance and in the energy of its physio- logical action. HgCl; 285.1. 376 MANUAL OP CHEMICAL ANALYSIS. When obtained by sublimation, it forms ponderous, yellowish- white masses or cakes, of a fibrous, crystalline fracture, yielding a lemon-yellow streak when scratched with a knife, and having a specific gravity of 7.176. When reduced to a fine powder by trituration and levigation, it has a dull-white appearance with a yellowish tint; it becomes slightly yellowish when triturated with strong pressure in a porcelain mortar, and consists, when seen under the microscope, of comparatively large, transparent, crystalline fragments (Fig. 124). Fig. 124. Fig. 125. Fig. 126. 250 diam. 250 diam. 250 diam. Prepared by sublimation and by condensation of tbe vapor by a current of air or steam, mercurous chloride (Hydrargyri Chlo- ridum Mite vapore paratum) forms a perfectly white and less ponderous powder (specific gravity 6.56), consisting of smaller laminar particles, when seen under the microscope (Fig. 125). Prepared by precipitation, mercurous chloride forms a fine snow-white powder, consisting of minute, amorphous* particles (Fig. 126), which are not transparent, and are devoid of odor or taste. With regard to therapeutical action, mercurous chloride, ob- tained by sublimation and subsequent trituration and levigation. and consisting of the largest particles, has the mildest effect; next to this comes the calomel obtained by sublimation and con- densation by air or steam ;f that obtained by precipitation, and having the minutest division of its particles, has the more power- ful physiological action. Mercurous chloride, when heated in a dry test-tube, is slowly but completely volatilized with a faint noise and without fusion. It is insoluble in the common solvents, but soluble to some extent in saliva, in the pancreatic juice, in albumen, and animal secre- * When obtained by precipitating a solution of mercuric chloride with sul- phurous-acid gas, the resulting mercurous chloride is of a crystalline structure. f No other kinds of mercurous chloride can as yet be considered officinal, and no others should be dispensed for internal use, unless ordered or pre- scribed, than “ Calomel via humida paratum,” or “ Calomel precipitaiione paratum.” HYDRARGYRUM. 377 tions. When agitated with hot water, with alcohol, or with dilute acetic, hydrochloric, or nitric acids, it is not acted upon by any of them. When boiled for some time with water, it suffers slow decomposition into metallic mercury and mercuric chloride; the decomposition being greater in extent when, instead of pure water, solutions of the alkaline chlorides are employed. The fixed alkaline hydrates and carbonates, and the hydrates of the alkaline earths, reduce mercurous chloride to black oxide ; the same conversion of mercurous chloride to oxide is also occa- sioned by its exposure to light, and by contact with many organic substances. Concentrated boiling hydrochloric and sulphuric acids decompose the salt; the former producing metallic mercury and mercuric chloride, the latter mercuric sulphate and chloride. Warm concentrated nitric acid also dissolves it gradually, with the evolution of nitric oxide vapors, forming a solution of mer- curic chloride and nitrate, which solution blackens bright copper when dropped upon it, and coats it brilliantly when rubbed upon it. Mercurous chloride is also soluble in chlorine-water without acquiring a transient or permanent yellow color (distinction from mercurous bromide). Examination: When heated in a narrow test-tube, mercurous chloride must completely sublime, without previous fusion and without emitting ammoniacal odors or yellow nitrous vapors. Mercuric chloride may be most quickly detected by placing a little of the mercurous chloride, previously moistened with water to the consistence of a thin paste, upon a piece of bright iron, and allowing the mixture to repose thereon for one or two minutes; if mercuric chloride is present, it will become instantly decom- posed, and there will appear upon the iron, after the removal of the mixture by rinsing with a little water, a deep, dull-black stain ;* it may also be detected by triturating some of the calomel Avith diluted alcohol, agitating the mixture in a test-tube, and subsequently filtering through a moist double filter; the filtrate must impart no stain to bright copper, nor yield any reaction with hydrogen sulphide or with argentic nitrate. Ammoniated mercury (white precipitate) may be detected by the development of the odor of ammonia, when the mercurous chloride is heated, in a test-tube, with a concentrated solution of potassium or sodium hydrate ; or, Avhen the mercurous chloride of the preceding test, remaining upon the filter, is rinsed with diluted acetic acid through the broken filter into a test-tube, and the mixture agitated for a few minutes and filtered. The filtrate is then tested in separate portions with hydrogen sulphide and * Pure mercurous chloride will produce under the same circumstances, by prolonged contact with the iron, a slight grayish film upon the latter, which, however, cannot be mistaken for the characteristic black stain produced by the mercuric salt. 378 MANUAL OF CHEMICAL ANALYSIS. argentic nitrate; a black turbidity in the first instance, and a white one in the second, would indicate ammoniated mercury. Non-volatile impurities, such as the sulphates or carbonates of the alkaline earths, may readily be detected when a little of the mercurous chloride is completely volatilized by strongly heating in a test-tube; any residue thus obtained may be further exam- ined for its identification, if desired, according to the systematic methods of analysis, as described on pages 51 to 61. HYDRARGYRI CYANIDUM. HYDRARGYRUM CYANATUM. Cyanide of Mercury. Mercuric Cyanide. Ger. Quecksilbercyanid ; Fr. Cyanure de mercure ; Sp. Cianuro de mercurio. IIg(CN)2; 251.7. Colorless, anhydrous, needle-shaped crystals, or lustrous quad- ratic prisms (Fig. 127), transparent when freshly prepared, but soon assuming a white and opaque appearance ; when perfectly dry, and carefully heated in a dry tube, they become decomposed into me- tallic mercury and a colorless inflammable gas (cyanogen), which burns, when ignited, with a purple flame; when quickly heated, a black residue of paracyanogen, intermingled with globules of mercury, is left behind, which, however, upon more strongly heating, is com- pletely dissipated ; when the salt is humid, traces of hydrocyanic acid, of carbonic acid, and of ammonia, are also formed and evolved. Mercuric cyanide is soluble in 12.8 parts of water and in 14.5 parts of alcohol at 15° C. (59° F.), in 3 parts of boiling water and in 6 parts of boiling alcohol, but almost insoluble in absolute alcohol and ether; its aqueous solu- tion possesses a disagreeable metallic taste, and is decomposed by hydrochloric acid and by hydrogen sulphide, with the liberation of hydrocyanic acid and the formation of mercuric chloride or sulphide, but is not decomposed bv dilute sulphuric or nitric acid, and is not precipitated by the alkaline hydrates and carbonates, by argentic nitrate, or by albumen; stannous chlo- ride, containing free hydrochloric acid, precipitates metallic mer- cury with the evolution of hydrocyanic acid. The solution of mercuric cyanide affords no mercuric stain upon bright metallic copper, unless the latter be previously moistened with hydro- chloric acid; it readily dissolves mercuric oxide, and, on evapo- Fig. 127. HYDRARGYRUM. 379 rating tlie alkaline solution thus obtained, small needle-shaped crystals of an oxy-cyanide, Hg30(CN)2, are formed. Examination: Mercuric oxy-cyanicle is indicated by an alkaline reaction of the solution upon turmeric-paper. Mercuric chloride and other soluble mercuric salts may be de- tected in the solution, by the occurrence of a transient turbidity upon the gradual addition of single drops of solution of potassium iodide, or by the production of a precipitate upon the addition of the alkaline hydrates or carbonates. HYDRARGYRI IODIDUM RUBRUM. Red Iodide of Mercury. Biniodide of Mercury. Mercuric Iodide. Ger. 'Quecksilberjodid ; Fr. Bi-iodure de mercure ; Sp. Bi-ioduro de mercurio. HYDRARGYRUM BIIODATUM. Hgl2; 452.9. A heavy, amorphous, scarlet-red powder, or small, brilliant, octahedral crystals, belonging to the quadratic system, and hav- ing a specific gravity of 6.3. When gently heated in a dry tube Fig. 128. 380 MANUAL OF CHEMICAL ANALYSIS. (Fig. 128) to about 150° C. (302° F.), mercuric iodide first becomes of a pure yellow color, then, when near the melting-point, deep orange, and finally melts at 253-254° C. (487.4-489.2° F.) to a blood-red liquid; at this temperature the volatilization of the iodide begins, when it sublimes undecomposed in the form of yel- low rhombic scales, which pass into the red modification of octa- hedral crystals, slowly on cooling, and at once by concussion. If the salt be heated with solution of sodium hydrate, and a little sugar of milk added, a precipitate of metallic mercury is produced; and if heated with sulphuric acid and a little manga- nese dioxide, the vapor of iodine is evolved. Mercuric iodide is nearly insoluble in cold, and only very spar- ingly soluble in boiling, water; it is soluble in 130 parts of cold, and 15 parts of boiling, alcohol, less soluble in ether, and very little in glycerin and in oils. Concentrated acids, and the solu- tions of the alkaline hydrates, decompose it; it is freely soluble in aqueous solutions of potassium and sodium hydrates, of potas- sium iodide and cyanide, of mercuric chloride, and of sodium chlo- ride and sodium hyposulphite; the latter solution deposits, upon gently heating, if the solvent is not in excess, red mercuric sul- phide, while, upon boiling, black mercuric sulphide, mixed with mercurous iodide and metallic mercury, is separated. All its solutions form a black precipitate upon saturation with hydrogen sulphide, either at once, or upon the addition of an acid. Mercuric iodide is partly decomposed when shaken with chlo- rine-water ; the obtained filtrate, when rubbed upon bright copper, coats it with a brilliant metallic film, and, when shaken with a little chloroform, imparts to the latter a purple color. Examination: Mercuric iodide, when heated to a temperature above 150° C. (302° F.), should assume a uniform .yellow color, and, at a higher temperature, should become completely volatilized; with hot alcohol it must afford a complete and colorless solution, without acid reaction, from which, upon cooling, the larger portion of the iodide is separated in a crystalline form ; the cold filtered solu- tion, upon the subsequent addition of ammonia-water, should not assume more than a brown coloration, and afford no precipitate. When digested with cold or hot water, or with acetic acid of the spec. grav. 1.040, no appreciable amount should be dissolved. Soluble iodides or chlorides may be detected in the mercuric iodide by digesting a little of the salt with water, filtering, and testing the filtrate with argentic nitrate; a white or yellowish- white turbidity or precipitate would indicate the presence of such admixtures. Mercuric sulphide, red oxide of lead, or other fraudulent admix- tures, will remain undissolved upon digesting the powder, either in solution of potassium iodide, or in twenty to twenty-five parts of boiling alcohol. If a residue is left, it is washed with water, and subsequently treated with warm nitric acid, and filtered ; the HYDRARGYRUM. 381 filtrate is slightly diluted, and tested with a few drops of diluted sulphuric acid ; an ensuing white precipitate indicates lead. If a red residue remains, insoluble in nitric acid, it is tested by heat- ing it upon platinum-foil to redness; if it is wholly volatile, mer- curic sulphide is recognized, and, if a residue remains, fixed ad- mixtures are indicated. HYDRARGYRI IODIDUM VIRIDE. HYDRARGYRUM IODATUM. Green Iodide of Mercury. Protoiodide of Mercury. Mercurous Iodide. Ger. Quecksilberjodur; Fr. Protoiodnre de mercure ; Sp. Protoioduro de mercuric). Hgl; 326.3. A heavy powder, of a dull-green or greenish-yellow color, which suffers gradual decomposition and becomes brownish on exposure to light, heat, and air. When heated in a dry tube (Fig. 128, page 379), it begins, at 70° C. (158° F.), to assume a red color, which increases in intensity until, at 200° C. (392° F.), it acquires a deep garnet-red color; at 220° C. (428° F.) it softens, and melts at 290° C. (554° F.), but begins to sublime, at 190° C. (374° F.), and by slow sublimation forms small, transparent, yellow crystals of the quadratic system, having the specific gravity of 7.6; when quickl}' and strongly heated, it suffers • a partial decomposition into metallic mercury and mercuric iodide, which do not again combine upon cooling. Mercurous iodide is not quite insoluble in water, but wholly insoluble in alcohol and in ether; it is decomposed by concen- trated acids, by the alkaline hydrates, and also by boiling solu- tions of the alkaline chlorides, bromides, and iodides, being- converted by the latter into mercuric iodide and metallic mer- cury. When mercurous iodide is agitated in a little water to which a few drops of ammonium sulphide have been added, the liquid filtered, and the filtrate, after acidulating with hydro- chloric acid, mixed with a few drops of a solution of ferric chloride and then agitated with a little chloroform, the latter will acquire a purplish or violet-red color, due to the presence of free iodine, which will appear still more distinct upon the subsequent addition of a little water. Examination: Mercuric iodide may be detected when 1 gram of the powder is agitated and digested with about 10 cubic centimeters of alcohol, subsequently filtered, and the filtrate dropped into water, when not more than a slight transient opalescence should be produced; and when 5 cubic centimeters of the filtrate are evaporated from a white porcelain surface, not more than a faint red stain should 382 MANUAL OF CHEMICAL ANALYSIS. remain behind; neither should the filtrate afford more than a very slight eoloration or turbidity upon saturation with hydrogen sulphide, otherwise the presence of an undue amount of biniodide or mercuric salt is indicated. Fixed impurities will remain behind upon the complete vola- tilization of the mercurous iodide in a dry tube; such would be very likely to originate from either the mercury or the iodine, and, if required, their nature may be determined by the methods described on pages 388-390 and 395-396. HYDRARGYRI OXIDUM FLAVUM. HYDRARGYRUM OXYDATUM VIA HUMIDA PARATUM. Yellow Oxide of Mercury. Precipitated Mercuric Oxide. Ger. Gelbes Quecksilberoxyd ; Fr. Oxyde de mercure jaune ; Sp. Protoxido de mercurio. IlgO; 215.7. A heavy, orange-yellow powder, without crystalline structure when seen under the microscope, permanent in the air, and having a specific gravity of 11.3. It becomes darker on expo- sure to the light, and assumes a red color on being heated; at a higher temperature it is decomposed with the evolution of oxygen and the separation of mercury, and is finally entirely volatilized. It is more readily acted upon by reagents than the coarser red oxide; the latter remains unchanged when agitated with a warm solution of oxalic acid, while the yellow oxide combines with the oxalic acid, forming white mercuric oxalate; when agitated with a hot alcoholic solution of mercuric chloride, the yellow oxide becomes at once black, in consequence of the formation of mercuric oxychloride (HgCl2.2IIgO), while the red oxide remains unchanged for some time. The chemical reactions of the precipitated yellow mercuric oxide, and its deportment with reagents, correspond with those of the red oxide. HYDRARGYRI OXIDUM RUBRUM. HYDRARGYRUM OXYDATUM. Red Oxide of Mercury. Red Precipitate. Mercuric Oxide. Ger. Rothes Quecksilberoxyd; Fr. Oxyde de mercure rouge ; Sp. Deutoxido de mercurio. Heavy, coherent masses, consisting of bright, brick-red, crys- talline scales, which, when finely pulverized, form a dull orange- HgO; 215.7. HYDRARGYRUM. 383 red powder, of a specific gravity of 11.186; when heated in a dry tube, red mercuric oxide first changes to a dark cinnabar-red color, and afterwards assumes a black tint, but regains its original color on cooling; at temperatures above 400° C. (752° F.) it is completely resolved into its constituents, and is entirely vola- tilized below a red heat, while at a much lower temperature it suffers a partial dissociation. Mercuric oxide is slightly soluble in water, so that, when agi- tated with boiling water, the filtrate possesses a decided metallic taste, an alkaline reaction upon litmus, and affords with ammo- nium sulphide a slight brown coloration; it is insoluble in pure glycerin, in alcohol, ether, and chloroform, somewhat soluble in saliva and in albuminous animal secretions, and entirely soluble in strong and in somewhat diluted acids. The fixed alkaline and earthy hydrates and alkaline carbonates produce in solutions of mercuric oxide and its salts, when added in small quantity, a red- dish-brown, when added in excess, a yellow precipitate ; ammonia- water, a white one; iodides (provided that the solution does not contain a large excess of acid), when added in small quantity, a yellowish, and in a larger quantity, a vennilion-red one, soluble in an excess of the precipitant; stannous chloride, when added in small quantity, gives a white, and, in excess, a gray precipitate. When water saturated with hydrogen sulphide is gradually added to the solution, or when the latter is slowly saturated with the gas, a precipitate is formed which appears, according to the pro- Fig. 129. portion of the reagent, successively white, yellow, orange, reddish brown, and finally, with an excess of the precipitant, black. 384 MANUAL OF CHEMICAL ANALYSIS. Examination: Mercuric nitrate is indicated by the disengagement of red nitrous vapors, when the oxide is heated in a dry test-tube. As a con- firmatory test, and one permitting the detection of much smallei quantities of nitrate, about 0.5 gram of the oxide is mixed with 10 drops of water, in a test-tube, then three times its volume of concentrated sulphuric acid added, and to the mixture, after being well agitated and subsequently allowed to repose, a saturated solution of ferrous sulphate is carefully added so as to form two layers (Fig. 129); the occurrence of a dark brown zone at the line of junction of the two liquids will confirm the presence of nitrate. Admixtures.—A small portion of the oxide is gently heated with about ten times its weight of dilute nitric acid, when com- plete solution should take place; if the oxide be very old, a slight residue of reduced mercury might remain, which, when separated and heated in a porcelain capsule, should wholly volatilize. If a red or brown residue is left from the solution, an admixture of Fig. 130. mineral substances (brick-dust, mercuric sulphide, or red oxide of lead) would be indicated. If the nature of such a residue has to be ascertained, a somewhat larger quantity may be obtained, which, when washed and dried, may be heated in a reducing-tube HYDRARGYRUM. 385 (Fig. 130); vermilion volatilizes, forming a fine, red sublimate ; red oxide of lead fuses, and exhibits, when cooled, a yellow vitri- fied appearance, and dissolves, when boiled in concentrated nitric acid diluted with an equal bulk of water, leaving behind silicious mineral substances, if such be present. The solution of the oxide in dilute nitric acid may also be tested with argentic ni- trate, which should afford no turbidity, thus establishing the absence of chlorides. HYDRAR6YRI SUBNITRAS. HYDRARGYRUM NITRICUM OXYDULATUM. Subnitrate of Mercury. Mercurous Nitrate. Ger. Salpetersaures Quecksilberoxydul; Fr. Azolate mercurieux; Sp. Protonitrato de mercurio. HgN08+H20; 279.7. Colorless, transparent monoclinic tables or prisms,* containing one molecule (6.5 per cent.) of water of crystallization, which is lost on exposure to dry air or by standing over sulphuric acid; they melt at 70° C. (158° F.), and when gradually heated in a dry tube, emit }mllow nitrous vapors, become yellow, then red, and are finally resolved into metallic mercury; the crystals become grayish-black when moistened with lime-water. Mercurous nitrate is soluble in a small amount of warm water, but, upon the addition of more water, it becomes decomposed, with the separation of a yellow basic salt, HgN03 + HgOH, while an acid nitrate remains in solution; it is, however, entirely solu- ble in water acidulated with nitric acid, forming a colorless solu- tion, which, when rubbed on bright copper, coats it with a white, metallic film, and, when largely diluted, yields a white precipi- tate with hydrochloric acid, and a black one with ammonia or lime-water. Liquor Hydraryyri Nitrici Oxydulati of German pharmacy is a solution of this salt, containing 10 per cent, of mercurous nitrate. Examination: Mercuric nitrate may be detected by completely precipitating the solution of the salt in cold dilute nitric acid with diluted hydrochloric acid, and testing the filtrate, in separate portions, with hydrogen sulphide and with stannous chloride, and warm- ing; a black precipitate with the first reagent, and a gray one with the second, would indicate mercuric nitrate. * According to the proportion between the mercury and the nitric acid em- ployed in the preparation, there is formed a normal or a basic mercurous nitrate, which correspond in their chemical and therapeutical properties, except that, when rubbed with a little sodium chloride, the normal salt remains white, while the basic salt gives a grayish-green mixture. 386 MANUAL OF CHEMICAL ANALYSIS. HYDRARGYRI SUBSULPHAS FLAVUS. HYDRARGYRUM SULFURICUM FLAVUM. TURPETIIUM MINERALE. Yellow Subsulphate of Mercury. Basic Mercuric Sulphate. Turpeth Mineral. Ger. Basiscli Seliwefelsaures Qnecksilberoxyd ; Fr. Sous-sulfate tie mercure ; Sp. Sullato basico de mercurio. HgS04 -f 2HgO ; 727.1. A heavy, lemon-yellow powder, of a crystalline structure when seen under the microscope, having a specific gravity of 8.3, and possessing an acrid taste. When heated in a dry tube, it assumes a reddish-brown hue, but regains its original color on cooling; at a higher temperature it volatilizes without fusion, yielding a white sublimate (mercuric sulphate) intermingled with gray me- tallic mercury ; it is decomposed and entirely volatilized at a red heat, evolving vapors of mercury and of sulphurous acid. Basic mercuric sulphate is almost insoluble in cold, and spar- ingly soluble in hot, water, but soluble in diluted hydrochloric and nitric acids, forming colorless solutions which, when diluted, give a white precipitate with soluble barium salts, and which otherwise, in their deportment with reagents, resemble the solu- tions of mercuric chloride and oxide (pages 374 and 383). HYDRARGYRI SULFHIDUM RUBRUM. HYDRARGYRUM SULFURATUM RUBRUM. CINNABARIS. lied Sulphide of Mercury. Cinnabar. Vermilion. Mercuric Sulphide. Ger. Scliwefelquecksilber, Zinnober ; Fr. Sulfure de mercure rouge ; Sp. Deutosulfuro de meicurio. HgS; 281.7. Heavy masses, or cakes, of a specific gravity of 8.124, and of a dull blackish-red color,and a brilliant crystalline texture,yielding a red streak when scratched with a knife, and a magnificent scarlet powder, which becomes black when moistened with an ammoni- acal solution of argentic nitrate. When heated to 250° C. (482° F.), mercuric sulphide becomes brown, at a higher temperature, black, and, on cooling, reassumes its red color; at a strong heat, with exposure to the air, it is wholly dissipated, burning with a blu- ish flame, and emitting the odor of sulphurous acid ; when gently heated in a small glass tube, it softens, and sublimes without pre- vious fusion, but undergoes partial dissociation into a black mix- ture of mercuric sulphide, mercury, and sulphur, with the evolu- tion of a little sulphurous acid ; when heated in closed vessels, HYDRARGYRUM. 387 with exclusion of the air, it sublimes below a red heat, without decomposition, in the form of beautiful red, crystalline crusts. Mercuric sulphide is insoluble in the common solvents, nor is it acted upon by officinal hydrochloric or nitric acid, or by alka- line hydrates, at common temperatures; boiling concentrated sul- phuric acid decomposes it, with the formation of mercuric sul- phate, attended by the separation of sulphur and the evolution of sulphur dioxide; it is also soluble in concentrated hydriodic acid in the cold, and in the dilute acid when warmed, with the evo- lution of hydrogen sulphide; nitro-hydrochloric acid (aqua regia) dissolves it readily, even in the cold, with the formation of mer- curic chloride and sulphuric acid, and the separation of sulphur, and yielding a colorless solution which, when diluted with water, gives a white precipitate with barium chloride, coats metallic copper with a film of mercury, and corresponds in its deportment with reagents to solutions of mercuric salts (pages 374 and 383). Examination: Oxides of Lead and Iron.—Such admixtures will be indicated by the incomplete volatilization of the mercuric sulphide when strongly heated in a small glass tube; their presence may be confirmed by agitating a small portion of the salt, in a test-tube, with about five times its weight of concentrated nitric acid; the scarlet color must remain unaltered, as change to a darker tint would indicate red oxide of lead; the mixture is then gently heated by immers- ing the test-tube in hot water, and is subsequently diluted with twice its volume of water, and filtered; the filtrate should be colorless; a yellowish appearance would indicate red basic plumbic chromate, or mercuric chromate (chromic cinnabar); it is then tested in separate portions with hydrogen sulphide, with sulphuric acid, and with potassium iodide, for lead ; another portion is tested with potassium ferrocyanide for ferric oxide; if this be present, the yellowish color of the nitric acid, agitated with the cinnabar, may be due only to iron. Chromates may be detected or confirmed by the occurrence of red irritating fumes of ohloro-chromic anhydride (Cr02Cl2), when a small portion of the mercuric sulphide is carefully mixed and heated in a test-tube with a few small fragments of dry sodium chloride and a few drops of concentrated sulphuric acid. Mercuric Iodide, Realgar, and Antimonic Cinnabar.—A portion of the mercuric sulphide is agitated with about five times its weight of a warm concentrated solution of potassium hydrate, the liquid subsequently diluted with an equal volume of water, and filtered; the filtrate should be colorless, should cause neither a coloration nor a turbidity when dropped into chlorine-water, and should not afford a colored precipitate when dropped into a dilute solution of plumbic acetate. A yellow or reddish coloration of the chlorine-water would indicate mercuric iodide, and a black precipitate with plumbic acetate, red arsenic sulphide (Kealgar), 388 MANUAL OF CHEMICAL ANALYSIS. or antimonic oxy-sulphide (Antimonic Cinnabar). If either of the latter two be indicated, the alkaline filtrate will give, upon supersaturation with hydrochloric acid, a yellow precipitate when the first compound is present, and an orange-red one with the second. HYDRARGYRUM. Mercury. Quicksilver. Ger. Quecksilber ; Fr. Mercure ; Sp. Mercurio. A silver-white and brilliantly lustrous metal, having a specific gravity of 13.595 at 0° C. (32° F.) compared with water at 4° C. (39.2° F.), or 13.573 at 15° C. (59° F.). It is liquid at common temperatures, and easily divisible into spherical globules, but solidifies when cooled to —39.38° C. (—38.88° F.), forming at and below that temperature a ductile, malleable mass, capable of being cut with a knife, and crystallizing in octahedrons of the regular system, which have a specific gravity of 14.39; it boils at 357.25° 0. (675.05° F.), forming a transparent, colorless vapor, but is volatile to a perceptible extent at ordinary temperatures, both in a vacuum and in air. When pure, it is unalterable by the action of the air at common temperatures, and remains bright and brilliant. Mercury is insoluble in the common solvents, in concentrated hydrochloric acid, and, at common temperatures, also in sulphuric acid; but it is dissolved by the latter when boiled with it, and is readily dissolved without residue by nitric acid, forming a solution, which contains mercuric nitrate when heat is applied and an excess of concentrated acid, and mercurous nitrate when the metal is in excess or is acted upon by cold and diluted nitric acid. Examination: Mercury amalgamates with many metals, and, to a certain ex- tent, without change of its appearance and properties; the most common of such metallic impurities are lead and tin, and occa- sionally zinc and bismuth; their presence in the commercial metal is indicated by a dull, tarnished appearance, and a black, powdery coating of the surfaces of the metal, and of the inside of the vessels containing it, and by lead-gray streaks upon white paper when a few globules of the metal are allowed to roll over it. Such contamination may be ascertained by agitating for a few minutes a little of the mercury, in a strong bottle, with a moder- ately dilute solution of ferric chloride (free from ferrous salt); after subsiding, the aqueous liquid is poured into a test-tube, diluted with an equal volume of water, and tested with a few Hg; 199.7. HYDRARGYRUM. drops of a solution of potassium ferricyanide; a blue turbidity will indicate the above-mentioned metallic impurities. When their nature has to be determined, the following method is practicable and simple. About 20 grams of the metal, includ- ing as much of the powdery coating on the surfaces of the metal and the bottle as can be collected, is heated and volatilized in a small porcelain crucible, in a place where the vapors are readily removed by draught; if a non-volatile residue remains, it is heated to redness. A small part of the residue is then heated in a test-tube with a few drops of concentrated hydrochloric acid; the solution is decanted from the insoluble residue, and, after the addition of a little nitric acid or chlorine-water, one drop of solu- tion of auric chloride is added; an ensuing purple or violet-red turbidity would indicate tin. The rest of the residue in the crucible is treated with warm con- centrated nitric acid; if only partial solution takes place, and at the same time a white precipitate is formed, this may be oxide of tin or antimony; in order to distin- guish them, the precipitate is separated from the acid solution, washed with a lit- tle water, and subsequently heated upon charcoal be- fore the blow-pipe; stannous oxide remains unchanged, while antimonicoxide volatil- izes in white fumes, forming a white concentric incrusta- tion on the coal (Fig. 131). The nitric acid solution is diluted with an equal bulk of water, and part of it is tested with solution ot sodium sulphate ; a white precipitate would indicate lead; another part is poured into a large beaker full of water ; a white opalescence or turbidity of the water indicates bismuth. If lead be present, the rest of the nitric acid solution is satu- rated and completely precipitated with hydrogen sulphide, and allowed to stand in a corked test-tube for some hours; it is then filtered and supersaturated with ammonia-water; a white pre- cipitate would indicate zinc. If the precipitate is not quite white, and the lead has been completely removed, it might be due to traces of iron, of which metal, however, mercury can only contain traces, since it does not amalgamate with it. An efficient and satisfactory method for the purification ot mercury, when contaminated with foreign metals, consists in shaking it vigorously with an equal volume of a solution com- posed of 5 grams of potassium bichromate and 5 grams of pure Fig. 131. 390 MANUAL OF CHEMICAL ANALYSIS. concentrated sulphuric acid in 1 liter of water. The metal is reduced to small globules, while a very small part of it is con- verted into red chromate. The agitation is continued until the red powder has disappeared and the aqueous solution has acquired a pure green color, due to the chromium sulphate formed. By means of a powerful current of water, which is passed into the flask, the gray powder upon the surface of the mercury, which is composed of the oxides of the metallic impurities, is washed aAvay. The process of oxidation is repeated once or twice, according to the degree of impurity, until gray powdery particles are no longer formed, when the mercury is finally thoroughly Avashed with distilled water until it remains perfectly clear. HYDRARGYRUM AMMONIATUM. HYDRARGYRUM AMID ATO -BICHLORATUM. HYDRARGYRUM AMMONIATUM BICHLORATUM. HYDRARGYRUM TATUM ALBUM. Ammoniated Mercury. White Precipitate. Mer cur ammonium Chloride. Ger. Quecksilberamidoehlorid ; Fr. Mercure precipite blanc; Sp. Precipitado bianco. NH2HgCl; 251.1. White, pulverulent, friable masses, or a perfectly white, ino- dorous powder, having a specific gravity of 6.7, and developing a styptic taste when placed upon the tongue; it is decomposed and entirely volatilized, Avithout fusion, at temperatures beloAV a red- heat, forming calomel, ammonia, and nitrogen: 6NH2HgCl = 6HgCl + 4NH3 + N2, It becomes black in contact with hydrogen sulphide, gray when boiled with solution of stannous chloride, and pale yellow, with the evolution of ammonia, when heated with a solution of potas- sium or sodium hydrate. When intimately mixed and triturated, in its dry condition, with iodine, it becomes gradually decomposed with slight deflagration, and with the formation of mercuric chlo- ride and iodide, ammonium chloride, ammonia, and nitrogen gases; the reaction is facilitated by the presence of a little water, but, if alcohol be poured upon the mixture, a violent explosion ensues. Ammoniated mercury is insoluble in the common solvents, and is gradually decomposed by prolonged Avashing with cold Avater, more quickly by boiling Avater, into ammon urn chloride, and a heavy, yellow, insoluble poAvder of hydrated dimercurammonium chloride [IIg2(NH)2C10]; it is readily and wholly soluble with- out effervescence in warm hydrochloric, nitric, and acetic acids, forming colorless solutions, which, after dilution with water, HYDRARGYRUM. yield a white prec:pitate with a cold solut:on of potassium hy- drate and with argentic nitrate, a black one with an excess of hydrogen sulphide, and a red one with potassium iodide, and which produce a black stain upon bright, metallic copper, coating it, when rubbed thereon, with a brilliant metallic film. Examination: Mercuric chloride is detected by agitating a small portion of the powder with about ten times its weight of diluted alcohol, filter- ing, and testing the filtrate with hydrogen sulphide and with potassium iodide ; a black precipitate with the first-named re- agent, and a red one with the latter, soluble in an excess of the precipitant, will indicate mercuric chloride. Mercurous chloride may be detected by a black coloration of the powder, when it is triturated with lime-water, or by dissolving a small portion of the powder in warm diluted nitric acid ; if an insoluble residue remains, it is washed by decantation, and, when the water ceases to act on blue litmus-paper, the residue is agitated with lime-water; if mercurous chloride, it will become black. Plumbic Carbonate and Chloride, and Calcium Carbonate.— Car- bonates are ind’cated by effervescence of the powder with acids, and plumbic chloride by its solubility in hot water (from which it separates in a crystalline form upon cooling), and by its very sparing solubilty in diluted hydrochloric and nitric acids. The presence of lead and calc’urn salts may be further confirmed by dissolving a portion of the powder in warm acetic acid, filtering, and testing a little of the filtrate with sulphuric acid, when a white precipitate will indicate lead, and, if the solution is not too dilute, the possible presence also of calcium ; if a precipitate is produced, the remaining portion of the acetic acid solution is com- pletely saturated with hydrogen sulphide, subsequently filtered, and the filtrate tested with ammonium oxalate, when a white pre- cipitate will reveal the presence of calcium. Zinc and magnesium oxides may be detected in the solution of the powder in hydrochloric acid, after dilution with water, by complete precipitation with hydrogen sulphide, and by subsequent neutralization of the filtrate with ammonia-water, and the addition of ammonium sulphide; a white prec pltate will indicate zinc; after the complete precipitat’on of the latter, and subsequent fil- tration, the solution is boiled for a few minutes, and, after being allowed to cool, is tested by the addition of a solution of sodium phosphate and a little ammonia-water, when the formation of a white crystalline precipitate will reveal the presence of magnesium. These and all other non-volatile admixtures are also indicated by remaining behind when a few grains of the ammoniated mercury are heated and volatilized, in a narrow, dry test-tube. Mercurdiamrnonium chloride. (NH3)2IIgCi2, or fusible white pre- cipitate, will be indicated in this test by a partial or complete 392 MANUAL OF CHEMICAL ANALYSIS. fusion of the powder, previous to its volatilization, provided that the ammoniated mercury be free from any fixed fusible admixture. Starch.—An admixture of starch is detected by the microscope, by the powder becoming charred when strongly heated on plati- num-foil, and also by a blue coloration, when a small portion of the powder is triturated, and subsequently heated to boiling, with a little water, and then tested with one drop of iodinized potas- sium iodide. HYOSCYAMINE! SULPHAS. HYOSCYAMINUM SULFURICUM. Sulphate of Hyoscyamine. Hyoscyamine Sulphate. Ger. Scliwefelsaures Hyoscyamin ; Fr. Sulfate de hyoscyamine ; Sp. Sulfato de hiosciamina. (C17H23N03),II2S04; 676. Small, golden-yellow, or yellowish-white scales or crystals, or a yellowish-white, amorphous powder, deliquescent on exposure to the air. When heated on platinum-foil, the salt is decomposed with the separation of carbon, and is finally completely dissipated. Hyoscyamine sulphate is very freely soluble in water and in alco- hol. Its aqueous solution is neutral in its action upon litmus, possesses a bitter and acrid taste, and yields with solution of barium chloride a white precipitate, insoluble in hydrochloric acid; it is also precipitated by most alkaloidal reagents, potassio- mercuric iodide, iodinized potassium iodide, picric acid, etc., but not by solution of platinic chloride ; with auric chloride, however, it yields a precipitate, which, when recrystallized from boiling water acidulated with hydrochloric acid, is deposited, on cooling, in brilliant, lustrous, golden-yellow scales, without rendering the liquid turbid (distinction from atropine). IODOFORMUM. ' IODOFORMIUM. Iodoform. Teriodide of Formyl. Methenyl Iodide. Ger. Jodoform ; Fr. Iodoforme ; Sp. Iodoformo. CHI3; 392.8 Small, lemon-yellow, friable, six-sided scales (Fig. 132), of a pearly lustre, a peculiar, penetrating, and persistent odor, and a IODUM. 393 sweetish taste, and with a somewhat unctuous feel to the touch. Iodoform has a spec. grav. of 2.0, is volatile at common temperatures, and when heated in a dry tube, by immersing it in boiling water, sublimes rapidly at about 95° C. (203° F.), solidifying in small scales, and may be distilled with aqueous vapor without decomposition ; it fuses at 120° CV. (248° F.), and is decomposed above this temperature, or when quickly heated, forming violet vapors, and being resolved into iodine and hydriodic acid, with a residue of carbon, which burns away at a stronger heat. Iodoform is almost insoluble in water, glycerin, diluted acids, and aqueous solutions of the alkaline and earthy hydrates, but is soluble in 80 parts of cold, and 12 parts of boiling, alcohol, in 5.2 parts of ether, and readily in chloroform, carbon bisulphide, benzol, benzin, and in the fixed and volatile oils. Concentrated mineral acids, when cold, have no action on iodoform; when heated, it remains unchanged with hydrochloric acid, gives a red- dish-brown solution with nitric acid, remaining limpid and brown on dilution with water; it is freely dissolved, with a violet color, by hot sulphuric acid; upon dilution, however, the color disap- pears, and the iodoform is separated again in small yellow scales. It is not acted upon by the aqueous solutions of the alkaline hydrates, but their alcoholic solutions dissolve and decompose it, forming alkaline iodide and formiate. Examination: Chlorides, Iodides, and Sulphates.—A small portion of the iodo- form is agitated with a little water for a few minutes, filtered, and the filtrate, after acidulation with a few drops of nitric acid, tested in separate portions with argentic nitrate and barium chloride; a white, curdy precipitate with the first-named reagent will indi- cate a contamination with chlorides or iodides, while a heavy white precipitate with the latter will reveal the presence of sul- phates. Fig. 132. IODINUM. IODINIUM. IODUM. Iodine. Ger. Jod ; Fr. lode ; Sp. Iodo. I; 126.6 Heavy, brilliant, crystalline plates or scales, of an opaque bluish-black appearance and imperfect metallic lustre, which 394 MANUAL OF CHEMICAL ANALYSIS. may be obtained from tbeir solution in liydriodic acid in well developed octahedral combinations of prisms or pyramids of the rhombic system (Fig. 133). Iodine possesses a peculiar odor, less penetrating than, although similar to, that of chlorine and bromine. Its specific gravity is 4.948 at 17° C. (62.6° F.); it melts at 114° C. (237.2° F.), and boils at a tem- perature above 2003 C. (392° F.), giving rise to a vapor which, seen by transmitted white light, possesses, when chemically pure, a splendid deep blue color, but when mixed with air, a reddish- violet color; it is, however, slowly volatile at common temperatures. When heated in a dry tube (Fig. 134), the vapors condense in the cooler parts of the tube to small, brilliant crystals. Fig. 183. Fig. 134. Iodine is but sparingly soluble in water, requiring 4500 parts of it at 15° 0. (59° F.), and imparting to it a faint brownish-yel- low tinge. It is more soluble in glycerin, 100 parts of which dissolve a little more than 1.5 parts of iodine. It is also soluble to some extent in the aqueous solutions of certain salts, as for instance of ammonium chloride and nitrate. Aqueous solutions IODUM. 395 of hydriodic acid and of the alkaline iodides and bromides, dis- solve iodine freely, as do also alcohol and ether, with a reddish- brown color, benzol and chloroform with a violet-red, and carbon bisulphide with a rich purple. An aqueous solution of sodium hyposulphite dissolves iodine at first without color, and afterward with a brownish-red tint. Chloroform and carbon bisulphide, when shaken with an aqueous solution of iodine, deprive it of most of the iodine, and assume, when the fluids have separated, a more or less red color, while the aqueous solution appears almost colorless. Iodine forms with starch a deep-blue compound, which offers a very delicate test for iod.ne in all solutions and in bodies which contain it in the free state; the reaction is, however, impaired by the presence of certain nitrogenized organic substances, such as albumen, etc., as also by quinine and tannic acid. Examination: Moisture is indicated in iodine by its adhering to the surface of the bottles, and by a sticky coherence of the scales, as also by the separation of globules of water when the iodine is dissolved in chloroform or carbon bisulphide; its amount may be quanti- tatively determined bv triturating a weighed amount of the iodine (about 2 grams) in a small porcelain capsule (the weight of which, together with that of the pestle, has been previously deter- mined) with about double its weight of mercury and a little alcohol, sufficient to moisten the mixture, until complete combi- nation is effected and free iodine can no longer be detected, either by the eye or by its odor; the mixture of mercurous iodide and mercury is then heated to 100° C. (212° F.) until its weight re- mains constant, when the weight of the applied iodine and mer- cury, minus the weight of the dried mixture, will represent the amount of water contained in the iodine employed. Iodine cyanide, ICN, will be indicated by its exceedingly irri- tating odor, and may be detected by agitating the iodine with a little water for a few minutes, filtering, and adding to the filtrate sufficient of a solution of potassium hydrate to produce a colorless or nearly colorless solution; a few drops of a solution of ferrous sulphate and ferric chloride are then added, and subsequently hydrochloric acid in slight excess, when the formation of a blue precipitate, either at once or upon standing, will confirm the presence of iodine cyanide. Chlorine and Bromine.—A small portion of the iodine is dis- solved in sulphurous acid, the colorless solution strongly super- saturated with ammonia water, and subsequently completely precipitated by argentic nitrate, and filtered; the filtrate, upon supersaturation with nitric acid, should not become cloudy nor yield a precipitate; a white precipitate will indicate the presence of chlorine or bromine, as also of cyanogen, in case the latter should have been confirmed by the preceding test. 396 MANUAL OF CHEMICAL ANALYSIS. Fixed and insoluble admixtures (graphite, coal, carburet of iron, metallic oxides or sulphides) are detected by remaining behind upon the volatilization of a little of the iodine in a test-tube, or upon solution of it in alcohol or in an aqueous solution of potas- s um hydrate or sodium hyposulphite. If the nature of such admixtures has to be determined, the residue is collected and washed upon a filter, and afterward treated with warm hydro- chloric acid diluted with an equal bulk of water, which dissolves Fig. 135. metallic oxides, and to some extent the sulphides, with the evolu- tion of hydrogen sulphide. The obtained solution may further be examined for metals, as described in the systematic course of analysis (pages 51 to 61). The insoluble residue left from the solution in hydrochloric acid is levigated (Fig. 135), whereby graphite and carburet of iron may be separated and distinguished from heavier mineral substances. Estimation: About 0.5 gram of the iodine, accurately weighed, is dissolved, in a small flask, in about 10 cubic centimeters of an aqueous ten per cent, solution of potassium iodide. When complete solution has taken place, a standard solution of sodium hyposulphite (page 94) is allowed to flow into the liquid from a burette, until a slight excess has been employed and complete decolorization of the liquid is effected; a little mucilage of starch being then added, the solution is subsequently titrated with a standard solu- tion of iodine (page 93), until a permanent blue coloration is pro- duced. The number of cubic centimeters of the sodium hypo- sulphite solution employed, minus that of the standard iodine solution, when multiplied by its previously accurately determined factor (page 95), will represent the amount of pure iodine in the quantity applied for the test, from which the percentage of impu- rities may readily be calculated. By the employment of 0.633 LIQUORES. 397 gram of iodine, dissolved in a solution of 1 gram of potassium iodide in 25 cubic centimeters of water, and a precisely deci- normal solution of sodium hyposulphite, the number of cubic centimeters required of the latter, when multiplied by 2, will represent, without further calculation, the exact percentage amount of pure iodine in the specimen under examination. LIQUOR AMMONII ACETATIS. Solution of Ammonium Acetate. Spirit of Mindererus. LIQUOR AMMONII ACETICI Ger. Essigsaure Ammoniumlosung; Fr. Acetate d’ammoniaque liquide ; Sp. Solucion de acetato de amoniaco. A clear, colorless liquid, without empyreumatic odor, and of a mild, saline taste; it contains about 7.6 per cent, of neutral am- monium acetate, and has a spec. gray, of 1.022 (1.032-1.034, Pharm. German., corresponding to 15 per cent, of ammonium acetate) ; it is wholly volatile upon evaporation, and emits the odor of ammonia when heated with potassium hydrate, and that of acetic acid when heated with sulphuric acid ; it assumes a red color upon the addition of a trace of ferric chloride, and, upon heating, the entire amount of iron is precipitated as a basic salt. Examination: Metallic impurities may be detected in the solution, after acidu- lation with hydrochloric acid, by a dark coloration or precipitate upon saturation with hydrogen sulphide, and, after filtration, if necessary, and subsequent neutralization with ammonia-water, by a turbidity or precipitate on the addition of ammonium sulphide. >Sulphates and chlorides may be detected by a white turbidity, when the liquid is acidulated with nitric acid and tested, in sepa- rate portions, with barium nitrate for the former salts, and with argentic nitrate for the latter. LIQUOR ANTIMONII CHLORIDI. LIQUOR STIBII CHLORATI. BUTYRUM ANTIMONII CHLORIDI. Solution of Trichloride of Antimony or of Antimonious Chloride. Ger. Antimonclilorurlosung ; Fr. Chlornre d’antimoine liquide ; Sp. Solucion de cloruro de antimonio. A dense, transparent, colorless or pale-yellow liquid, having a specific gravity of about 1.470. Dropped into water, it gives a white, bulky precipitate (antimonious chloride with antimonious MANUAL OF CHEMICAL ANALYSIS. oxide—Algaroth's Powder\ which is re-dissolved upon the addition of potassium hydrate or tartaric acid. The solution with potassium hydrate remains unchanged, or gives only a slight turbidity, with hydrogen sulphide, and yields a black precipitate with argentic nitrate; while the solution with tartaric acid gives a copious orange-red precipitate with hydrogen sulphide, and a white one with argentic nitrate. Examination: A small portion of the solution, when exposed to a moderate heat in a porcelain capsule, should be completely volatilized. Antimonic chloride is detected in the solution, diluted with an aqueous ten per cent, solution of tartaric acid, in order to avoid precipitation, by the occurrence of a brown coloration on the addition of a few drops of a solution of potassium iodide. Iron and copper may be detected in the solution, after complete precipitation with hot water and subsequent filtration, by the addition of a few drops of solution of potassium ferrocyanide; a blue coloration or precipitate will reveal the presence of iron, a reddish-brown one, that of copper. Lead will be indicated by the separation of a white precipitate when the solution of antimonious chloride is mixed with twice its volume of alcohol, and may be further confirmed by the following test: A small portion of the solution is diluted with water, and subsequently solution of potassium hydrate added until the trans- parency of the liquid is again restored ; it is then saturated with hydrogen sulphide, when a black coloration will reveal the pres- ence of lead, a white turbidity, that of zinc. Arsenic.—A portion of the solution is completely precipitated by hot water, filtered, and the filtrate saturated with hydrogen sulphide. The ensuing precipitate, which may consist of arsenic trisulphide, accompanied by a small amount of antimony, is col- lected upon a filter, washed with water, and digested with a con- centrated solution of ammonium carbonate. The latter solution is then filtered, and, upon evaporation to dryness, will leave the arsenic, if present, in the form of yellow arsenic trisulphide; the latter may be further examined, if required, by fusing it with a mixture of sodium nitrate and carbonate in a small porcelain cru- cible, dissolving the fused mass in a little water, and testing it in Marsh’s apparatus (F,g. 20, p. 34), or it may be mixed with a little exsiccated sodium carbonate and potassium cyanide, and heated in a small reduction-tube (Fig. 64, p. 128), when a mirror of metallic arsenic will be produced. Sulphuric and Nitric Acids.—A portion of the solution is com- pletely precipitated with water, filtered, and the filtrate tested, with barium chloride for sulphuric acid, and, in another portion, by the addition of a drop of indigo solution and heating, for nitr.c acid; the presence of the latter will be ind cated by ensuing de- coloration of the liquid. LIQUORES. LIQUOR CALCIS. AQUA CALCIS. AQUA CALCARIrE. Ger. Kalkwasser; Fr. Eau de clianx ; Sp. Agua de cal. Lime- Water. Solution of Calcium Hydrate. A clear, colorless, and odorless liquid, consisting of a saturated solution of calcium hydrate, and having, at 15° C. (59° F.), a spe- cific gravity of 1.0015. It possesses a saline and feebly caustic taste and an alkaline reaction, and contains in solution about 0.128 per cent, of calcium oxide, or 0.17 per cent, of calcium hydrate. Lime-water readily absorbs carbonic acid from the air, forming on its surface a pellicle consisting of minute plates of cal- cium carbonate; its alkaline reaction disappears when an excess of carbonic acid gas has been passed through it, and the excess has been expelled afterward by boiling. Lime-water affords no precipitate with sulphuric acid (distinc- tion from solution of barium or strontium hydrate), but it forms white precipitates with carbonic, boracic, phosphoric, arsenious and arsenic, oxalic, and tartaric acids and their salts, and precipi- tates the solutions of those salts whose metallic oxides or hydrates are insoluble in water. The quality of lime-water is best ascertained by its property, when warmed in a test-tube, of separating nearly half the quan- tity of calcium hydrate in minute hexagonal prisms; upon cool- ing, the crystals red'ssolve, and the water becomes perfectly clear again. The presence or absence of alkalies (potassium or sodium hydrate) or alkaline carbonates may be determined by saturating the lime-water with carbonic acid gas, and subsequently heating to boiling; the filtered liquid must be neutral to test-paper; an alkaline reaction would indicate the above-mentioned impurities. LIQUOR FERRI ACETATIS. LIQUOR FERRI ACETICI.* Ger. Essigsaure Eisenoxydlosung ; Fr. Liqueur d’acetate de fer ; Sp. Acetato de liierro liquido. Solution of Acetate of Iron. Solution of Ferric Acetate. A transparent, dark reddish-brown liquid, containing 33 per cent, of anhydrous ferric acetate, Fe2(C2H302\j, corresponding to * Liquor Ferri Acetici. of the Pharmacopoea Germanica, is prepared by the precipitation of 10 parts of solution of ferric chloride, of 1.280 to 1.282 spec, grav., diluted with 50 parts of water, with a mixture of 10 parts of ammonia-water, spec. grav. 060, and 200 parts of water ; the precipitate is collected and washed 400 MANUAL OF CHEMICAL ANALYSIS. 7.93 per cent, of metallic iron, and having a spec. grav. of 1.160 at 15° C. = 59° F. (1.081 to 1.083, Pharm, Germ., corresponding to from 4.5 to 5 per cent, of metallic iron, or from 18.7 to 20.8 per cent, of anhydrous ferric acetate); it has a faint odor of acetic acid, which becomes more evident upon warming; this may also be recognized by the formation of white vapors, when a glass rod, moistened with ammonia-water, is held over the liquid. Solution of ferric acetate yields with ammonia-water a reddish- brown precipitate, and with potassium ferrocyanide, a deep-blue one; and, when largely diluted with water, should afford with a few drops of a freshly prepared solution of potassium ferricyanide a pure greenish-brown coloration, without a blue tint (evidence of the absence of ferrous salts). If the solution be heated to boil- ing, it becomes turbid, in consequence of the separation of insoluble basic ferric acetate. Examination: A small portion of the liquid is diluted with twice its volume of water, and the iron completely precipitated by the addition of a considerable excess of ammonia-water and heating to boiling; the filtrate must be wholly volatile when a few drops of it are evaporated in a porcelain capsule or on platinum-foil; a viscid residue, which becomes charred at a stronger heat, with the evo- lution of vapors having the odor of caramel, would indicate sugar or fruit-acids, which, when present in considerable quantities, pre- vent the complete precipitation of the ferric solution by ammonia- water. A bluish tint of the filtrate would indicate copper, which, with other metallic impurities, may be further determined by saturating it with hydrogen sulphide, both before and after acidu- lation with hydrochloric acid. Hydrochloric and Sulphuric Acids.—A portion of the solution, diluted with an equal volume of water, is heated until the iron has become completely precipitated, and filtered ; the filtrate, after acidulation with nitric acid, is then tested, in separate portions, with argentic nitrate for hydrochloric acid, and with barium nitrate or chloride for sulphuric acid. The verification of the proper amount of iron in the solution may be accomplished by reference to its specific gravity, and by evaporating 10 grams of the solu- tion, to which a few drops of nitric acid have been added, to dryness, in a small platinum capsule, and subsequently igniting at a red heat; the residue of ferric oxide thus obtained should weigh 1.13 grams. upon a flannel or felt filter, and afterward subjected to strong pressure. The soft, humid mass of ferric hydrate is then transferred to a flask, 8 parts of dilute acetic acid, spec grav. 1.041, added, and the mixture allowed to stand in a cool place, with frequent agitation, until the precipitate has become entirely dis- solved, or but a slight insoluble residue remains ; so much water is then added that the solution shall have the spec. grav. 1.081 to 1.083. LIQUORES. 401 LIQUOR FERRI CHLORIDI. LIQUOR FERRI SESQUICHLORATI.* Solution of Chloride or Perchloride of Iron. Solution of Ferric Chloride. Ger. Eisenchloridlosung ; Fr. Chlorure de fer liquide ; Sp. Solucion de percloruro de hierro. A dark reddish-brown liquid, having a faint odor of hydro- chloric acid, an acid, strongly styptic taste, and an acid reaction. Its specific gravity is 1.405 at 15° C. (59° F.), and it contains 37.8 per cent, of anhydrous ferric chloride. It is miscible in all proportions with alcohol, water, and glycerin, and the solution after admixture with alcohol is not rendered turbid on the sub- sequent addition of ether. The diluted aqueous solution affords a brownish-red precipitate on the addition of ammonia-water, a blue one with potassium ferrocyanide, and a white one, insoluble in nitric acid, with solution of argentic nitrate. Examination: Ferric oxy-chloride may be detected by the occurrence of a tur- bidity, when 3 parts of the solution are diluted with water to the measure of 100 parts, and subsequently heated to boiling. Ferrous chloride may be recognized in the diluted solution by an ensuing blue coloration or precipitate on the addition of a freshly prepared solution of potassium ferricyanide. A portion of the solution, diluted with an equal volume of water, is completely precipitated by an excess of ammonia-water, filtered, and the filtrate divided into four portions, which may be employed for the following tests: Fixed alkalies or alkaline salts may be detected by a non-vola- tile residue upon evaporating a portion of the filtrate to dryness, and subsequent ignition at a gentle heat. Metallic Impurities.— Copper will be indicated by a blue color of the ammoniacal liquid; and zinc may be detected by a white turbidity or precipitate on the addition of a few drops of ammo- nium sulphide, or, after acidulation with hydrochloric acid, by a white precipitate on the addition of solution of potassium ferro- cyanide. Sulphuric acid will be indicated in the filtrate, after supersatu- ration with nitric acid, by a white precipitate on the addition of solution of barium chloride. Nitric acid may be detected in another portion of the filtrate, concentrated by evaporation, if necessary, by the addition of a slight excess of concentrated sulphuric acid, a drop of indigo solu- tion, and gently heating; ensuing decoloration of the liquid will * Liquor Ferri sesquichlorati, of the Pharmacopoea Germanica, has the spec, grav. 1.280 to 1.282, and contains 29 per cent, of anhydrous ferric chloride, corresponding: to 10 per cent, of metallic iron. 402 MANUAL OF CHEMICAL ANALYSIS. reveal the presence of nitric acid. Or, to a portion of the liquid, mixed with an excess of concentrated sulphuric acid, a crystal of ferrous sulphate is added, or a concentrated solution of the latter salt is carefully poured upon the liquid, so as to form two layers (Fig. 129, p. 383), when a dark coloration of the crystal, or a brown or violet-colored zone at the line of contact of the two liquids, will likewise indicate the presence of nitric acid. Estimation: The determination of the strength of liquor ferri chloridi may be readily accomplished, in addition to the verification of the proper specific gravity, by diluting 10 grams of the solution with an equal volume of water, heating to the boiling-point, and com- pletely precipitating the iron by the addition of ammonia-water in excess. The precipitate of ferric hydrate, when collected on a filter, thoroughly washed, dried, and ignited, should leave a residue of ferric oxide weighing 1.86 grams. LIQUOR FERRI CITRATIS. Solution of Citrate of Iron. Solution of Ferric Citrate. LIQUOR FERRI CITRICI. A dark brown, transparent liquid, without odor, and having a slightly ferruginous taste, and an acid reaction. It has a spec, grav. of 1.260, and contains about 35.5 per cent, of anhydrous ferric citrate, Fe2(C6Il407)2, corresponding to 8.1 per cent, of me- tallic iron. When the solution is concentrated by evaporation, at a gentle heat, and spread upon plates of glass, it forms, upon drying, transparent, garnet-red scales, which are easily detached from the glass. If 100 parts of the solution be thus treated, from 43 to 44 parts of the scaled salt should be obtained, which, when completely incinerated at a strong heat, in a small porcelain cru- cible, should leave a residue of ferric oxide, amounting to about 11 parts. Solution of ferric citrate is not precipitated, but is rendered somewhat darker, on the addition of ammonia-water ; and yields, with solution of potassium ferrocyanide, a bluish-green color or precipitate, which is rendered dark blue on the subsequent addition of hydrochloric acid. If the solution be boiled with an excess of solution of potassium hydrate, a reddish-brown precipitate of ferric hydrate is produced ; the filtrate therefrom, after concentra- tion and being allowed to cool, is precipitated by solution of cal- cium chloride, and the filtrate from the latter precipitate, when heated to boiling, yields a white, granular precipitate of calcium citrate. LIQUORES. 403 LIQUOR FERRI ET QUININiE CITRATIS. LIQUOR FERRI CITRICI CUM CIIININO CITRICO. Solution of Citrate of Iron and Quinine. Solution of Ferric and Quinine Citrates. A dark greenish-yellow to yellowish brown liquid, transparent when diluted or in thin layers, without odor, and having a bitter and mildly ferruginous taste, and a slightly acid reaction. It contains 6 per cent, of quinine, which has been dried at 100° C. (212° F.). If the solution be supersaturated with a slight excess of ammo- nia-water, a white, curdy precipitate is produced, which corre- sponds to the reactions and tests of quinine, and the liquid assumes a somewhat darker color. If the mixture be then filtered, and a portion of the filtrate slightly supersaturated with hydrochloric acid, a deep blue precipitate is produced. Another portion of the filtrate, when heated with an excess of solution of potassium hydrate, yields a reddish-brown precipitate of ferric hydrate ; the filtrate therefrom, after concentration and being allowed to cool, is precipitated by solution of calcium chloride, and the filtrate from the latter precipitate, when heated to boiling, yields a white granular precipitate of calcium citrate. On heating the solution with a strong solution of potassium hydrate, vapors of ammonia are evolved. Estimation of the Quinine in Solution of Citrate of Iron and Qui- nine : Eight grams of the solution, contained in a closely fitting, glass- stoppered bottle or flask, are diluted with water to the measure of 30 cub:c centimeters, an aqueous solution of 0.5 gram of tartaric acid added, and subsequently solution of sodium or potassium hy- drate, in slight excess. The mixture is then agitated with four successive portions of chloroform, of about 15 cubic centimeters each, the chloroformic layers being removed by means of a glass separating funnel, afterward mixed, and allowed to evaporate spon- taneously in a weighed glass or porcelain capsule, and finally dried at 100° 0. (212° F.), until of constant weight. The residue of quinine thus obtained should weigh 0.48 gram, corresponding to 6 per cent, of the weight of solution employed. 404 MANUAL OF CHEMICAL ANALYSIS. LIQUOR FERRI NITRATIS. LTQUOR FERRI NITRICI. LIQUOR FERRI PERNITRATIS. Solution of Nitrate or Pernitrate of Iron. Solution of Ferric Nitrate. Ger. Eisenoxydnitratlosung ; Fr. Solution d’azotate de fer; Sp. Solucion de pernitrato de liierro. A transparent amber-colored or reddisli-yellow liquid, having an acid, strongly styptic taste, and an acid reaction. Its specific gravity is 1.050 at 15° C. (59° F.), and it contains about 6 per cent, of anhydrous ferric nitrate. Diluted with water, it gives a deep-blue precipitate with potassium ferrocyanide, but none with potassium ferricyanide, and yields a reddish-brown precipitate with ammonia-water; when a few drops of a concentrated solu- tion of ferrous sulphate are added to a little of the solution of ferric nitrate, and the mixture is carefully transferred upon con- centrated sulphuric acid (Fig. 129, p.383), a dark zone, indicating nitric acid, will upon the line of contact between the two liquids. Examination: To a portion of the solution ammonia-water in slight excess is added, the liquid filtered from the precipitate of ferric hydrate, and the filtrate employed for the following tests : Metallic Impurities.— Copper will be indicated by a blue color of the ammoniacal liquid ; and zinc may be detected by a white turbidity or precipitate on the addition of a few drops of ammo- nium sulphide, or, after acidulating with hydrochloric acid, by a white precipitate when tested with potassium ferrocyanide. Hydrochloric and sulphuric acids may be detected in another portion of the filtrate, supersaturated with nitric acid, when tested respectively with argentic nitrate and barium nitrate or chloride. Estimation: In addition to the verification of the proper specific gravity, the strength of liquor ferri nitratis may readily be determined by completely precipitating 100 grams of the solution with ammo- nia-water. The precipitate of ferric hydrate, when collected on a filter, thorouglily washed, dried, and ignited, should leave a residue of ferric oxide weighing 2 grams. LIQUORES. 405 LIQUOR FERRI SULPHATIS. LIQUOR FERRI SULFURICI OXYDATI. Solution of Persulphate of Iron. Solution of Ferric Sulphate. Ger. Eisenoxydsulfatlbsung ; Fr. Liqueur de persulfate de fer; Sp. Solucion de persulfato de hierro. The U. S. Pharmacopoeia has two solutions of ferric sulphate, Liquor Ferri Subsulphatis, having a spec. grav. of 1.555, and Liquor Ferri Tersulqohatis, having a spec. grav. of 1.320. The former is a solution of basic ferric sulphate [Fe40(S04)s], contain- ing 43.7 per cent, of the salt; the latter, a solution of normal ferric sulphate, Pe2(S04)3, containing 28.7 per cent, of the salt.* The Liquor Ferri Persulphatis of the British Pharmacopoeia has the spec. grav. of 1.441, and that of the Pharmacopoea Germanica a spec. grav. of 1.428 to 1.430. They all are transparent, red or reddish-brown liquids, without odor, of an astringent, metallic taste, and miscible in all propor- tions, with water, alcohol, and glycerin, without decomposition. A few drops of either of them, added to water, form a mixture in which potassium ferricyanide produces no reaction, but ferro- cyanide gives a dark-blue precipitate, ammonia-water a bulky, reddish-brown one, and barium chloride a white one, the latter insoluble in hydrochloric acid. Examination: Copper and Zinc.—A small portion of either of the above solu- tions of ferric sulphate is mixed with about an equal volume of water, heated to boiling, and the iron completely precipitated by the addition of ammonia-water in excess, and filtered. The filtrate will appear bluish, if copper be present, and should be entirely volatilized when heated upon platinum-foil; a fixed residue wrould indicate alkaline, earthy, or metallic impurities. Part of the filtrate is then saturated with hydrogen sulphide, an ensuing white pre- cipitate would indicate zinc, and a dark one, insoluble upon supersaturation with hydrochloric acid, copper. Nitric acid and nitrates may be detected in a portion of the filtrate of the preceding test, by supersaturating it with concen- trated sulphuric acid, and by subsequently adding one drop of a solution of potassium permanganate, or indigo solution, and gently warming; ensuing decoloration will indicate nitric acid or nitrates. Estimation: In addition to the verification of the proper specific gravity, the strength of solutions of ferric sulphate may be readily determined * The two preparations may readily be distinguished by slowly mixing, in a beaker, 2 volumes of the solution with 1 volume of concentrated sulphuric acid ; the liquor ferri subsulpliatis separates a solid white mass on standing, while the liquor ferri tersulphatis retains its fluidity. 406 MANUAL OF CHEMICAL ANALYSIS. by completely precipitating 10 grams of the solution with an ex- cess of ammonia-water, collecting the precipitate of ferric hydrate on a filter, washing it thoroughly with water, and, after drying, igniting in a porcelain crucible at a red heat. Ten grams of liquor ferri subsulphatis should thus afford a residue of ferric oxide weighing 1.938 grams; and the same amount of liquor ferri tersulphatis, a residue of ferric oxide weighing 1.147 grams. LIQUOR HYDRARGYRI NITRATIS. LIQUOR HYDRARGYRI NITRICI OXYDATI. Solution of Nitrate or Pernitrate of Mercury. Solution of Mercuric Nitrate. Ger. Salpetersaure Quecksilberoxydlosung ; Fr. Nitrate de mercure iiquide ; Sp. Solucion de pernitrato de mercuric). A dense, transparent, nearly colorless, acid liquid, having a faint odor of nitric acid, and, even when diluted, a very acid, caustic and metallic taste. It has a specific gravity of 2.100 at 15° 0. (59° F.), when prepared according to the U. S. Pharma- copoeia, and of 2.246, when prepared according to the British Pharmacopoeia, containing, in the first instance, about 50 per cent, of mercuric nitrate in solution. When a few drops of the liquid are evaporated at a gentle heat, upon platinum-foil, they leave a white residue, which, upon in- creased heat, becomes successively yellow, red, and brown, and is finally wholly dissipated. The solution remains limpid on the addi- tion of water or of diluted hydrochloric acid (evidence of the ab- sence of mercurous nitrate); it gives a dull yellow precipitate with an excess of the fixed alkaline and earthy hydrates, a white one with ammonia-water, a bright red one with potassium iodide, soluble in an excess of the reagent, and a black one with an excess of hydrogen sulphide; it deposits a brilliant metallic coat- ing on bright copper, and shares, in its deportment with reagents, the general characteristics of mercuric salts, as described under mercuric chloride and oxide (pages 374 and 383). It causes a crystal of ferrous sulphate, dropped into it, as well as the liquid around the salt, to assume a deep-brown color. When diluted with about ten times its volume of water, it should not give a turbidity when tested, in separate portions, with a few drops of solutions of argentic and of barium nitrates (absence of chlorides and sulphates). LIQUORES. 407 LIQUOR PLUMBI SUBACETATIS. LIQUOR PLUMBI SUBACETICI. ACETUM PLUMBICUM. Solution of Subacetate of Lead. Solution of Triplumbic Acetate. Ger. Bleiessig ; Fr. Sous-acetate de plorab liquide ; Sp. Subacetato de plomo liquido. A dense, clear, colorless liquid, of 1.228 spec. gray. (1.235- 1.240 Pharmacopoea Grermanica), having an alkaline reaction and a sweet, astringent taste, and becoming turbid by absorption of atmospheric carbonic acid, and by dilution with water containing carbonates, sulphates, or carbonic acid. It is precipitated, whether diluted with water or not, by the alkaline and alkaline- earthy hydrates and carbonates, by sulphuric, hydrochloric, oxalic, tannic, and other acids and their salts, and by almost all neutral salts; it forms white, opaque, insoluble compounds with vegetable gums, mucilages, and extracts, and with vegetable and albuminous substances. Liquor plumbi subacetatis gives a yellow precipitate with potassium iodide, and a black one with hydrogen sulphide; it forms an opaque, white jelly when mixed with mucilage of gum; it may be recognized as containing an acetate, by evolving the odor of acetic acid, when heated with a few drops of sulphuric acid, and by affording a deep-red color, accompanied by the sepa- ration of plumbic chloride, on the addition of a few drops of a dilute solution of ferric chloride. Traces of copper are indicated by a faint greenish color of the liquid, and may be further recognized by a bluish coloration of the filtrate, when a little of the liquor plumbi subacetatis is mixed with an excess of ammonia-water. Estimation: 13.7 grams of the solution should require for complete precipi- tation 25 cubic centimeters of normal solution of oxalic acid (page 82), corresponding to 25 per cent, of basic plumbic acetate. By the employment of other quantities of the solution than that above mentioned, the calculation may also readily be made, with the consideration that 1 cubic centimeter of normal oxalic acid solution corresponds to 0.13675 gram of basic plumbic acetate, Pb20(C2H302)2. 408 MANUAL OF CHEMICAL ANALYSIS. LIQUOR FOTASSiE. LIQUOR POTASSII HYDRICI. LIQUOR KALII CAUSTICI. Ger. Kalilauge ; Fr. Liqueur de potasse ; Sp. Solucion de potasa. Solution of Potassa. Solution of Potassium Hydrate. A transparent, colorless, limpid liquid, without odor, of an extremely acrid and caustic taste and strongly alkaline reaction, and having a soapy feel when rubbed between the fingers. It lias a destructive action on many vegetable and animal sub- stances, is a powerful solvent for many organic and mineral com- pounds, and readily absorbs carbonic acid gas by exposure to the air; when dropped into a concentrated solution of tartaric acid, a white crystalline precipitate is produced, which is re-dissolved by an excess of the alkali. The specific gravity of the solution is 1.036 at 15° C. (59° F.), and it contains about 5 per cent, of potassium hydrate.* Examination: Carbonate is indicated by effervescence or by the formation of gas-bubbles, when the liquor potassm is added to an excess of hydrochloric or nitric acid ; it may also be detected by the for- mation of a white precipitate when a little of the liquor potassm is mixed with an equal volume of water, and is then added to lime-water. Sodium hydrate may be detected by the following method, which is based upon the solubility of sodium bitartrate, and the insolubility of potassium bitartrate, in alcohol. A weighed por- tion of the liquor potassas is exactly neutralized with tartaric acid, and to the solution as much tartaric acid subsequently added as was previously required for neutralization. Alcohol is then added until a precipitate ceases to be produced, and the liquid filtered. The filtrate, which will contain the sodium in the form of bitartrate, will deposit the latter upon evaporation, and, upon ignition, will leave a black, strongly alkaline residue of carbon and sodium carbonate. If this residue be dissolved in water, the solution filtered, neutralized with dilute nitric acid, and concen- trated by evaporation, rhombohedral crystals of sodium nitrate may be obtained, which impart an intense yellow color to the non-luminous flame. Potassium chloride, sulphide, and hyposulphite may be detected by dropping a little of the liquor potassse into diluted solution of argentic nitrate ; a grayish-brown precipitate will be produced, which, however, should be completely soluble upon the addition of nitric acid in excess; if the precipitate does not wholly dis- * Liquor Kalii caustici, of the Pharmacopoea Germanica, has a spec. grav. of from 1.142 to 1.146, and contains about 15 per cent, of potassium hydrate. LIQUORES. 409 solve, and leaves behind a white residue, chloride is indicated ; when the residue is black, sulphide or hyposulphite. Sulphate, Silicate, and Alumina.—A little of the liquor potassm is slightly supersaturated with diluted nitric acid; part of the solution is tested with barium nitrate for sulphate ; another part may also be tested with argentic nitrate for chloride; the rest of the solution is evaporated, in a porcelain capsule, to dryness; the remaining salt must yield a limpid solution with water; a white insoluble residue would indicate silicate; the solution, when necessary, is filtered, and then tested by the addition of a little ammonium chloride and ammonia-water for alumina, which, when present, will afford a white flocculent precipitate. Calcium salts may be detected, in the diluted liquor potassm, previously neutralized with nitric acid, by a. white precipitate with ammonium oxalate, or with sodium carbonate. Aletallic impurities are indicated by a dark coloration or tur- bidity when the liquor potassae is saturated with hydrogen sul- phide, either before or after supersaturation with hydrochloric acid. Estimation: The amount of pure potassium hydrate contained in liquor potassae may readily be determined volumetrically. About 20 grams of the liquid are accurately weighed in a beaker or small flask, a few drops of litmus solution added, and subsequently a standard solution of oxalic or sulphuric acid (page 82) allowed to flow into the liquid from a burette until, with constant stir- ring, .the blue tint of the liquid is just changed to a cherry-red. From the number of cubic centimeters of the acid solution thus required for exact neutralization, the amount of pure potassium hydrate may be calculated : one cubic centimeter of normal acid corresponding to 0.056 gram of potassium hydrate, KHO. By the employment of 28 grams of the officinal liquor potassae, not less than 25 cubic centimeters of the normal acid solution should be required for exact neutralization, indicating a strength of at least 5 per cent, of potassium hydrate. If the liquor potassae contain carbonate, the amount of carbon dioxide contained in a weighed portion of the solution must be determined, as described on pages 85-86. For 1 part of carbon dioxide, C02, 2.545 parts of potassium hydrate, KHO, are de- ducted from the amount volu metrically indicated, and the balance then calculated as pure potassium hydrate. 410 MANUAL OF CHEMICAL ANALYSIS. Table of the quantity by weight of Potassium Oxide and Hydrate con- tained in 100 parts by xoeight of solution (Liquor Potassce) of different specific gravities ( Gerlach). Temperature 15° C. (59° F.). Per ct. of K20 or" KHO. Specific gravity for K20. Specific gravity for KHO. Per ct. of K20 or KHO. Specific gravity for K20. Specific gravity for KHO. Per ct. of K20 or KHO. Specific gravity for K20. Specific gravity for KHO. 1 1.010 1.009 21 1.230 1.188 41 1.522 1.425 2 1.020 1.017 22 1.242 1.198 42 1.539 1.438 8 1.030 1.025 23 . 1.256 1.209 43 1.554 1.450 4 1.039 1.033 24 1.270 1.220 44 1.570 1.462 5 1.048 1.041 1 25 1.285 1.230 45 1.584 1.474 6 1.058 1.049 26 1.300 1.241 46 1.600 1.488 7 1.068 1.058 ' 27 1.312 1.252 47 1.615 1.499 8 1.078 1.065 28 1.326 1.264 48 1.630 1.511 9 1.089 1.074 29 1.340 1.276 49 1.645 1.527 10 1.099 1.083 30 1.355 1.288 50 1.660 1.539 11 1.110 1.092 31 1.370 1.800 51 1.676 1.552 12 1.121 1.101 32 1.385 1.311 52 1.690 1.565 13 1.132 1.111 i 33 1.402 1.324 53 1.705 1.578 14 1.143 1.119 34 1.418 1.336 54 1.720 1.590 15 1.154 1.128 | 35 1.431 1.349 55 1.733 1.604 16 1.166 1.137 36 1.445 1.361 56 1.746 1.618 17 1.178 1.146 ; 37 1.460 1.374 57 1.762 1.630 18 1.190 1.155 38 1.475 1.387 .58 1.780 1.641 19 1.202 1.166 39 1.490 1.400 59 1.795 1.655 20 1.215 1.177 40 1.504 1.411 60 1.810 1.667 With the decrease and increase of temperature, the specific gravity of the solution suffers a corresponding increase or decrease, amounting for each degree of the centigrade thermometer in either direction— For solution of a specific gravity of 1.810 to that of 1.504 to about 0.00055 “ “ “ 1.490 “ 1.855 “ 0.0005 “ “ “ 1.840 “ 1.230 “ 0.0004 “ “ “ 1.215 “ 1.010 “ 0.00033 LIQUOR POTASSII ARSENICOSI. LIQUOR KALII ARSENICOSI. Solution of Potassium Arsenite. Fowler's Solution. Ger. Fowler’sche Tropfen ; Fr. Solution arsenicale de Fowler ; Sp. Solucion de arsenito de potasa. LIQUOR POTASSII ARSENITIS. The officinal solution of potassium arsenite contains 1.656 per cent, of primary potassium arsenite, KH2As03, corresponding to 1 per cent, of arsenic trioxide, As203;* it has a slight alkaline * Liquor Kalii arsenicosi of the Pharmacopoea Germanica is an aqueous solu- tion of potassium metaarsenite, KAs02; and probably, also, of potassium ortho- arsenites, corresponding in amount to 1 per ceut. of arsenic trioxide, As20:1. LIQUORES. 411 reaction, and gives, with nitrate of silver, a bright-yellow precipi- tate, soluble in ammonia-wrater; this solution, when gently warmed for some time, by immersing the test-tube in hot water, suffers a reduction of the silver salt, and deposits the metal, as a brilliant coating, upon the walls of the test-tube. Hydrogen sulphide pro- duces no immediate precipitate in the solution of potassium arse- nite, but, upon the addition of hydrochloric acid, there at once appears a leinon-yellow precipitate, soluble in ammonia-water or in a concentrated solution of ammonium carbonate. Estimation: A quantitative estimation of the amount of arsenic trioxide (arsenious acid), corresponding to the amount of potassium ar- senite contained in liquor potassii arsenitis, may be made by diluting 10 grams of the solution with an equal volume of water, acidulating with hydrochloric acid, and subsequently completely precipitating with hydrogen sulphide. The precipitate is col- lected and washed upon a tared filter, and, after drying at 100° C. (212° F.), is weighed. The weight of the arsenious sulphide, divided by 1.242, gives the quantity of arsenious acid contained in 10 grams of the solution, which should be 0.1 gram. The quantitative estimation may also be made volumetrically, by the following method: 10 grams of the solution of potassium arsenite are accurately weighed in a beaker, and the solution diluted with about twice its volume of water. 2 grams of crys- tallized sodium carbonate are then dissolved in the liquid, a little mucilage of starch added, and subsequently a decinormal solution of iodine (page 93) allowed to flow into the liquid, from a burette, until a permanent blue coloration of the liquid is just produced. 20.2 cubic centimeters of the iodine solution should be required to produce this reaction, as corresponding to 0.1 gram of arsenic trioxide, or, the amount of the latter may readily be calculated, with the consideration that 1 cubic centimeter of decinormal iodine solution corresponds to 0.00495 gram of arsenic trioxide, As203. The United States Pharmacopoeia directs that if 24.7 grams of the solution are boiled with 0.5 gram of sodium bicarbonate, the liquid, when cold, diluted with 100 cubic centimeters of water, and some mucilage of starch added, should require from 48.5 to 50 cubic centimeters of the volumetric solution of iodine, before the blue color ceases to disappear on stirring (corresponding to 1 per cent, of arsenious acid of the required purity, or, at least, 0.97 per cent, of pure arsenious acid). 412 MANUAL OF CHEMICAL ANALYSIS. LIQUOR SODiE. LIQUOR SODII IIYDRICI. LIQUOR NATRII CAUSTICI. Ger. Natronlauge ; Fr. Soude caustique liquide ; Sp. Solucion de sosa. Solution of Soda. Solution of Sodium Hydrate. A transparent, colorless, limpid liquid, without odor, of an extremely acrid and caustic taste and strongly alkaline reaction, and having a soapy feel when rubbed between the lingers. It has a destructive action on many vegetable and mineral substances, is a powerful solvent for many organic and mineral compounds, and readily absorbs carbonic acid by exposure to the air; when dropped into a concentrated solution of tartaric acid, no precipi- tate is produced (distinction from solution of potassium hydrate); when a drop of the solution, contained on the looped end of a platinum-wire, is held in the non-luminous flame, it imparts to the latter an intense yellow color. The specific gravity of the solution is about 1.059 at 15° C. (59° F.), and it contains about 5 per cent, of sodium hydrate.* Examination: Sodium carbonate is indicated by effervescence, or by the forma- tion of gas-bubbles, when the liquid is added to an excess of con- centrated hydrochloric or nitric acid; it may also be detected by the formation of a white precipitate upon mixing a little of the liquid with twice its volume of lime-water. Sodium sulphate and chloride are indicated by white precipitates, when the diluted liquid is slightly supersaturated with nitric acid, and tested with barium nitrate for sulphate, and with argentic nitrate for chloride. Calcium salts may be detected by a white precipitate, when the diluted liquid, previously neutralized with nitric acid, is tested with solution of ammonium oxalate or sodium carbonate. Potassium hydrate may be recognized by a white, granular pre- cipitate, on dropping the liquid into a strong solution of tartaric acid, allowing the latter to remain in excess. Metallic impurities are indicated by a dark coloration or tur- bidity when the liquor sodse is saturated with hydrogen sulphide, either before or after supersaturation with hydrochloric acid. Estimation: The amount of pure sodium hydrate contained in liquor sodaa may readily be determined volumetrically. About 20 grams of the liquid are accurately weighed in a beaker or small flask, a few drops of litmus solution added, and subsequently a standard solution of oxalic or sulphuric acid (page 82) allowed to flow into * Liquor Natrii caustici of the Pharmacopoea Germanica has a spec. gray, of from 1.159 to 1.163, and contains about 15 per cent, of sodium hydrate. L1QU0RES. 413 the liquid from a burette, until, with constant stirring, the blue tint of the liquid is just changed to a cherry-red. From the number of cubic centimeters of the aeid solution thus required for exact neutralization, the amount of pure sodium hydrate may be calculated : one cubic centimeter of normal acid corresponding to 0.040 gram of sodium hydrate, NaHO. By the employment of 20 grams of the officinal liquor sodoe, not less than 25 cubic centi- meters of the normal acid solution should be required for exact neutralization, indicating a strength of at least 5 per cent, of sodium hydrate. If the liquor sodae contains carbonate, the amount of carbon dioxide contained in a weighed portion of the solution must be determined, as described on pages 85-86. For 1 part of carbon dioxide, C02, 1.818 parts of sodium hydrate, NaHO, are deducted from the amount volumetrically indicated, and the balance then calculated as pure sodium hydrate. Table of the quantity by iceight of Sodium Oxide and Hydrate contained in 100 parts by iceight of solution (Liquor Sodce) of different specific gravities ( Gerlach). Temperature 15° C. (59° F.). Per ct. of Na20 or " NaHO. Specific gravity for Na.,0. ' Specific graviiy for NaHO. Per ct. of Na20 or NaHO. Specific gravity for Na^O. Specific gravity for NaHO. Per ct. of Na20 or NaHO. Specific gravity for Na20. Specific gravity for NaHO. 1 1 015 1 012 21 1.300 1 236 41 1 570 1.447 2 1 029 1 023 22 1.315 1 247 42 1 583 1.456 3 1 043 1 035 23 1.329 1 258 43 1 597 1.468 4 1 058 1 046 24 1.341 1 269 44 1 610 1.478 5 1 074 1 059 25 1.355 1 279 45 1 623 1.488 6 1 089 1 070 26 1.369 1 290 46 1 637 1.499 7 1 104 1 081 27 1.381 1 300 47 1 650 1.508 . 8 1 119 1 092 28 1.395 1 310 48 1 663 1.519 9 1 132 1 103 29 1.410 1 321 49 1 678 1.529 10 1 145 1 .115 30 1-422 1 332 50 1 690 1.540 11 1 160 1 .126 31 1.438 1 343 51 1 705 1.550 12 1 175 1 137 32 1.450 1 351 52 1 719 1 .560 13 1 190 1 148 33 1.462 1 363 53 1 730 1.570 14 1 203 1 159 34 1.475 1 374 54 1 745 1.580 15 1 219 1 .170 35 1 .480 1 384 55 1 760 1.591 16 1 .233 1 .181 36 1.500 1 395 56 1 770 1.601 17 1 .245 1 .191 37 1.515 1 405 57 1 785 1.611 18 1 .258 1 .202 38 1.530 1 415 58 1 800 1.622 19 1 .270 1 .213 39 1.543 1 • 420 59 1 815 1.633 20 1 .285 1 .225 40 1.558 1 .437 60 1 830 1 -643 With the decrease and increase of temperature, the specific gravity of the solution suffers a corresponding increase or decrease, amounting, for each degree of the centigrade thermometer in either direction— For solution of a specific gravity of 1.830 to that of 1.355 to about 0.00045 “ “ “ “ 1.341 “ 1.219 “ 0.0004 “ “ “ “ 1.203 “ 1.015 “ 0.00033 414 MANUAL OF CHEMICAL ANALYSTS. LIQUOR SODiE CHLORATiE. LIQUOR SODE CHLORINATE. LIQUOR NATRII HYPOCIILOROSI. Solution of Chlorinated Soda. Solution of Sodium Hypochlorite. Ger. Unterclilorigsaure Natriumlosung; Fr. Eau de Labarraque ; Sp. Licor de Labarraque. A transparent liquid of a pale greenish-yellow color, having a faint odor, resembling that of chlorine, and a disagreeable alka- line taste and alkaline reaction. Its specific gravity is 1.04-1 at 15° C. (59° F.), and it contains about 2 per cent, of available chlorine. Solution of chlorinated soda becomes decomposed upon heat- ing, with the formation of sodium chlorate and chloride, and, upon exposure to sunlight, liberates oxygen, with the simultaneous formation of sodium chlorate, chlorite, and chloride. It possesses oxidizing properties, and is rendered much more energetic in its action by the addition of acids, in consequence of the developed chlorine; it rapidly decolorizes solution of indigo and other vegetable colors, and produces in the solutions of many metallic salts, such as lead, manganese, cobalt, and nickel, brown or black precipitates of the respective peroxides or perhydrates; when added to a solution of ferrous sulphate, a copious, light-brown pre- cipitate is produced, and with solution of mercuric chloride it affords a brown precipitate of mercuric oxychloride, IlgXJLO. Examination: Calcium salts will be indicated by a white precipitate on the addition of solution of sodium carbonate. Sodium carbonate, when present in any considerable excess, will be indicated bv the formation of a precipitate, when the solution of chlorinated soda is mixed with twice its volume of alcohol. Estimation; The value of solution of chlorinated soda depends upon the amount of available chlorine which it contains, which may readily be determined by the following method. 8.88 grams of the solution are mixed, in a beaker, with a solution of 2.6 grams of potassium iodide in 200 cubic centimeters of water; 18 grams of hydrochloric acid are subsequently added to the solution, together with a few drops of mucilage of starch, arid, after being well mixed, a standard solution of sodium hyposulphite (page 94) is allowed to flow into the liquid from a burette until, with constant stirring, complete decoloration of the liquid is effected. If the solution be of the proper strength, not less than 50 cubic cen- timeters of the solution of sodium hyposulphite should be re- quired to produce this reaction, indicating at least 2 per cent, of available chlorine. By the employment of other amounts of the solution of chlori LITHIUM. 415 nated soda, or, when the proportions above indicated are observed, the exact amount of available chlorine contained in the solution may also be calculated, by the consideration that 1 cubic cen- timeter of standard sodium hyposulphite solution corresponds to 0.0035 gram of free chlorine. LITHII BENZOAS. LITHIUM BENZOICUM. Benzoate of Lithium. Lithium Benzoate. Ger. Benzoesaures Lithium ; Fr. Benzoate de lithium ; Sp. Benzoato de litina. LiC7Hs02; 128. A white powder, or small shining scales, permanent in the air, of a faint benzoin-like odor, a cooling and sweetish taste, and a faintly acid reaction. On being heated, the salt first fuses, then, at a higher temperature, it chars, emitting inflammable vapors of a benzoin-like odor, and finally leaves a black residue of an alka- line reaction. A little of the'salt, when heated on the looped end of a platinum wire, in the non-luminous flame, imparts to the latter an intense carmine-red color. Lithium benzoate is soluble in 4 parts of water and 12 parts of alcohol at 15° C. (59° F.), in 2.5 parts of boiling water and in 10 parts of boiling alcohol, but is insoluble in ether. Its aqueous solution yields on the addition of a dilute solution of ferric chloride a flesh-colored precipitate of basic ferric benzoate, and with hydro- chloric acid a precipitate of benzoic acid, which redissolves on the subsequent addition of alcohol. Examination: Sulphates and chlorides may be detected in the diluted aqueous solution of the salt, strongly acidulated with nitric acid, and fil- tered, if necessary, by testing it in separate portions, with barium nitrate for the former, and with argentic nitrate for the latter. Potassium and Sodium Salts.—A small portion of the salt is ignited, in a porcelain crucible, at a red heat, the ignited residue dissolved in diluted hydrochloric acid, and the solution filtered and evaporated to dryness. 1 part of this residue should be com- pletely soluble in 3 parts of absolute alcohol, forming a solution which, when ignited, burns with a crimson flame, and which is not precipitated by the subsequent addition of an equal volume of stronger ether; if the ignited residue be incompletely soluble in alcohol, the presence of salts of the alkalies will be indicated. Calcium salts may be detected in the aqueous solution of the above-described ignited residue, by the formation of a white pre- cipitate when tested with solution of ammonium oxalate. 416 MANUAL OF CHEMICAL ANALYSIS. Metallic impurities may be detected in the aqueous solution of the salt, acidulated with hydrochloric acid, and filtered, if neces- sary, by a dark coloration or a turbidity when saturated with hydrogen sulphide, or, after neutralization with ammonia-water, by the addition of ammonium sulphide. LITHII BROMIDUM. LITHIUM BROMATUM. Bromide of Lithium. Lithium Bromide. Ger. Bromlitliium ; Fr. Bromure de lithium ; Sp. Bromuro de litio. A white, granular salt, very deliquescent on exposure to the air, neutral in its action upon litmus, and possessing a sharp and slightly bitter taste. On exposure to a low, red heat the salt fuses, and, at a higher temperature, it is slowly volatilized. A fragment of the salt,contained on the looped end of a platinum- wire, when brought into the non-luminous flame, imparts to the latter a carmine red color. Lithium bromide is very freely soluble in both water and alco- hol ; its aqueous solution yields on the addition of a solution of argentic nitrate a yellowish-white precipitate, which is soluble in a large excess of ammonia-water. If a little carbon bisulphide be poured upon a solution of the salt, a few drops of chlorine- water subsequently added, drop by drop, and the whole well agi- tated, the carbon bisulphide will acquire a yellowish or brownish- red color, but should show no violet tint. Examination: Alkaline bromides. iodides, and chlorides may be tested for by dissolving 0.1 gram of the dry lithium bromide in 10 cubic cen- timeters of water, adding thereto a solution of 0.2 gram of argentic nitrate in about 10 cubic centimeters of water, agitating the mix- ture, and filtering. The filtrate should not become turbid on the subsequent addition of solution of argentic nitrate, and the above- obtained precipitate should be completely soluble in a large excess of ammonia water; a turbidity in the first instance would indicate chloride, and incomplete solubility in the second instance, the presence of iodide. As a special test for potassium bromide, 0.1 gram of the dry lithium bromide and 0.19 gram of argentic nitrate are dissolved, separately, in small portions of water, the solutions mixed, agitated, and filtered; the filtrate should remain clear upon the addition of a few drops of hydrochloric acid; if a pre- cipitate is thereby produced, the presence of potassium bromide or other potassium or sodium compounds will be indicated. LiBr; 86.8. LITHIUM. 417 Potassium and Sodium Salts.—These impurities, in addition to the above tests, will be indicated by dissolving one part of the lithium bromide in three parts of absolute alcohol; a clear solu- tion should be formed, which should not be rendered turbid nor yield any precipitate on the subsequent addition of an equal volume of stronger ether, otherwise an admixture with salts of other alkalies will be indicated. Calcium salts may be detected in the aqueous solution of lithium bromide by a white precipitate when tested with solution of am- monium oxalate. Metallic impurities may be recognized in the aqueous solution of the salt, acidulated with hydrochloric acid, by a dark colora- tion or a turbidity when saturated with hydrogen sulphide, or, after neutralization with ammonia-water, by the addition of ammo- nium sulphide. LITHII CARBONAS. LITHIUM CARBONICUM. Ger. KohlensauresLithium ; Fr. Carbonate de lithium ; Sp. Carbonato de litina. Carbonate of Lithium. Lithium Carbonate. Li2C03; 74. A white, amorphous, or indistinctly crystalline powder, perma- nent in the air, odorless, of an alkaline taste and reaction, and having a specific gravity of 2.11. When a small portion of the salt is heated on the looped end of a platinum-wire, in the non- luminous flame, it fuses to a clear, colorless bead, and imparts to the flame a bright carmine-red color. Lithium carbonate is soluble in 130 parts of water at 15° 0. (59° F.), and in about the same quantity of boiling water; it is more freely soluble in solutions of ammonium salts, and is readily dissolved by dilute acids, with copious evolution of carbon di- oxide, but is insoluble in alcohol. If the solution of the salt in diluted hydrochloric acid be evaporated to dryness, the residue should be completely soluble in three parts of absolute alcohol, affording a solution which, when ignited, burns with a crimson flame, and which is not precipitated by the addition of an equal volume of stronger ether (distinction from potassium and sodium chlorides); if the acid solution of the salt be neutralized bv sodium hydrate, and a few drops of solution of sodium phosphate are subsequently added, and gently heated, a white, crystalline precipitate of lithium phosphate, readily soluble in hydrochloric acid, will appear. Examination: Potassium, and Sodium Carbonates.—The presence of these salts 418 MANUAL OF CHEMICAL ANALYSIS. may readily be ascertained by a greater solubility in water than that above indicated, as also by the above-described method, depending upon the solubility of lithium chloride in a mixture of alcohol and ether. Their presence may also be determined by the amount of acid required to exactly neutralize a definite amount of the salt: 0.74 part of lithium carbonate, when mixed with a warm solution of 1.26 parts of oxalic acid in 13 parts of water, should afford a clear and neutral solution ; or, 1 gram of lithium carbonate, if perfectly pure, should be exactly neutralized by 27.02 cubic centimeters of normal sulphuric acid. Potassium salts may be specially tested for, if desired, by dissolving a portion of the salt, in a test-tube, in an excess of solution of tartaric acid, and drawing a glass rod over the interior surface of the tube; the gradual formation of a white, crystalline precipitate will reveal the presence of potas- sium salts. Sodium salts may also be further recognized by their property of imparting an intense yellow color to the non-lumi- nous flame, when a portion of the carbonate, moistened with hydrochloric acid, is heated on the looped end of a platinum-wire. Ammonium salts may be recognized by the odor of ammonia, when a portion of the carbonate is heated, in a test-tube, with a concentrated solution of potassium or sodium hydrate. Calcium and magnesium salts, if present in the form of carbon- ates, will remain undissolved when the lithium carbonate is agi- tated writh 150 times its weight of water; they will also be indicated in the neutral solution of the salt (1: 150) in diluted hydrochloric acid bv a white precipitate on the addition of an excess of sodium carbonate. The presence of calcium salts may be further detected in the aqueous solution of the lithium car- bonate, previously neutralized with hydrochloric acid, bv a white turbidity with ammonium oxalate; after filtration, if necessary, and the addition of ammonium chloride, ammonia-water, and solution of sodium phosphate, an ensuing white crystalline pre- cipitate will reveal the presence of magnesium. Sulphates and chlorides may be detected in the solution of the carbonate in diluted nitric acid, when tested, in separate portions, with barium and argentic nitrates respectively. Metallic impurities may be recognized in the solution of the salt in diluted hydrochloric acid by a dark coloration or a turbidity upon saturation with hydrogen sulphide, or, after neutralization with ammonia-water, by the subsequent addition of ammonium sulphide. LITHIUM. 419 LITHII CITRAS. LITHIUM CITRICUM. Citrate of Lithium. Lithium Citrate. Ger. Citronensaures Lithium ; Fr. Citrate de lithium; Sp. Citrato de litina. Li3c6Hso7; 210. A white, amorphous, deliquescent powder, possessing a slightly cooling and faintly alkaline taste, and neutral in its action upon litmus. When exposed to a red heat, the salt chars, evolves inflammable vapors, and leaves a black residue of an alkaline reaction, which, when dissolved in a little alcohol, with one or two drops of hydrochloric acid, and ignited, imparts a crimson color to the flame. Lithium citrate is soluble in 5.5 parts of water at 15° C. (59° F.), and in 2.5 parts of boiling water, but is almost insoluble in alcohol and ether. When the aqueous solution of the salt is completely precipitated with calcium chloride, the filtrate, when heated, will become turbid, and when filtered after cooling, and the filtrate reheated to boiling, it becomes turbid again (evidence of the presence of a citrate). Examination: The purity of lithium citrate may be approximately deter- mined by adding to 1 gram of the salt, previously dried at 120° C. (248° F.), and contained in a porcelain crucible, about 3 grams of concentrated sulphuric acid, and gently heating. After com- plete carbonization, the residue is strongly ignited at a red heat, and, after cooling, is weighed. The weight of the lithium sulphate thus obtained should not exceed 0.79 gram, and, when multiplied by 1.278, will indicate the corresponding amount of pure lithium citrate. Potassium salts are detected in the concentrated solution of the citrate, by a white, crystalline precipitate, upon the addition of a few drops of concentrated solution of sodium bitartrate. Sodium salts are detected in the solution by a white precipitate when tested with potassium antimoniate, or by a persistent yellow color imparted to the non-luminous flame, when heated on the looped end of a platinum-wire. The presence of potassium and sodium salts may also be ascer- tained by dissolving, in one or two drops of diluted hydrochloric acid, the residue of lithium carbonate obtained by incineration of the citrate; this solution is evaporated to dryness, and is subse- quently dissolved in a few drops of a mixture of equal parts of alcohol and ether ; a complete solution should result, as an insolu- ble residue would indicate potassium or sodium chlorides. Metallic impurities may be detected in the solution, acidulated 420 MANUAL OF CHEMICAL ANALYSIS. with hydrochloric acid, by a dark coloration or a turbidity upon saturation with hydrogen sulphide, or, after neutralization with am- monia-water, by the subsequent addition of ammonium sulphide. LITHII SALICYLAS. LITHIUM SALICYLICUM. Salicylate of Lithium. Lithium Salicylate. Ger. Salicylsaures Lithium ; Fr. Salicylate de lithium ; Sp. Salicilato de litina. A white powder, deliquescent on exposure to the air, and con- taining, for two molecules of the salt, one molecule (5.88 per cent.) of water. When strongly heated, the salt chars, emits inflamma- ble vapors, and leaves finally a blackened residue of an alkaline reaction. A small portion of the salt, when heated on the looped end of a platinum-wire in the non-luminous flame, imparts to the latter a bright carmine-red color. Lithium salicylate is very freely soluble in both water and alco- hol. Its aqueous solution possesses a sweetish taste, and a faintly acid reaction, and yields, upon supersaturation with hydrochloric acid, a bulky white precipitate of salicylic acid, which is soluble in boiling water, and from which it recrystallizes on cooling; the precipitate is also readily soluble in alcohol and ether, and the solutions assume, on the addition of a drop of solution of ferric chloride, an intense violet color. Examination: Organic impurities mav, in most cases, be detected by agitating 1 part of the salt with about 15 parts of concentrated sulphuric acid, when no color should be imparted to the acid within 15 minutes; an ensuing dark coloration would indicate the presence of foreign organic substances. Carbonate will be indicated by effervescence, when a small por- tion of the salt is added to diluted hydrochloric or acetic acid. Potassium and sodium salts may be recognized by igniting a portion of the lithium salicylate at a red heat, dissolving the resi- due in diluted hydrochloric acid, and evaporating the clear, fil- tered solution to dryness. The residue of lithium chloride thus obtained should be completely soluble in 3 parts of stronger alco- hol, affording a solution, which, when ignited, burns with a crim- son flame, and the transparency of which is not disturbed by the subsequent addition of an equal volume of stronger ether; if an insoluble residue remains, the presence of potassium or sodium salts or other impurities will be indicated. Metallic impurities may be detected in the aqueous solution of 2LiC7H503.H20; 306. MAGNESIUM. 421 the salt, acidulated with hydrochloric acid, by a dark coloration or a turbidity upon saturation with hydrogen sulphide, or, after neutralization with ammonia-water, by the subsequent addition of ammonium sulphide. MAGNESIA. MAGNESIA USTA. MAGNESII OXIDUM. MAGNESIUM OXYDATUM. Ger. Gebrannte Magnesia ; Fr. Magnesie calcinee ; Sp. Magnesia calcinada. Magnesia. Calcined Magnesia. Magnesium Oxide. MgO; 40. A white, inodorous, bulky, more or less' light powder,* of an earthy, but not saline taste, and a slightly alkaline reaction upon moistened red litmus-paper; when exposed to a moderate heat, it suffers no change, but at very high temperatures it is rendered more dense, loses its property of combining with water, and is much more slowly soluble in acids. Magnesia is almost insoluble in water, requiring 55,368 parts of the latter for solution, but is much more soluble in solutions of various salts, particularly the ammonium salts; it is insoluble in alcohol. If one part of magnesia be stirred, in a beaker, with 15 parts of water, and the mixture allowed to stand for about half an hour, it readily unites with the water with the formation of a gelatinous hydrate, which is of sufficient firmness to prevent it from falling out when the glass is inverted, and gradually absorbs carbonic acid by exposure to the air. When magnesia is dissolved in diluted sulphuric acid, it affords a solution which, after the addition of ammonium chloride and supersaturation with ammonia-water, yields a white, crystalline precipitate on the addi- tion of solution of sodium phosphate. Examination: When triturated with hot water, and the mixture poured into an excess of dilute sulphuric acid, magnesia must dissolve with- out effervescence (evidence of the absence of carbonate), and must form a clear solution (evidence of the absence of calcium, barium, and strontium oxides); this solution may be divided into two portions, one of which is saturated with hydrogen sulphide, and after filtration, if necessary, and neutralization with ammonia- water, tested with ammonium sulphide; a dark coloration or a turbidity in either instance will indicate the presence of metallic * Iii the U. S. Pharmacopoeia magnesia is officinal in two forms, as Magne- sia, or light magnesia, and Magnesia Ponderosa, or heavy magnesia, which differ in their densities, but correspond in all their other properties and reactions. 422 MANUAL OF CHEMICAL ANALYSIS. impurities; the remaining portion of the solution, after the addi- tion of a little ammonium chloride and ammonia-water, is tested with ammonium oxalate, when a white precipitate will reveal the presence of calcium. Another portion of the magnesia may be dissolved in dilute nitric acid, and the solution tested, in separate portions with argentic nitrate for chlorides, and with barium nitrate or chloride for sulphates. Magnesia is liable to contain the impurities of the magnesium carbonate from which it has been obtained, and may be further examined for them, if they have not been ascertained by the preceding tests for identity and purity, by the methods described on page 428. MAGNESII CARBONAS. MAGNESIUM CARBONICUM. MAGNESIA ALBA. Carbonate of Magnesium. Magnesium Carbonate. Ger. Basiscli kohlensaures Magnesium; Fr. Carbonate de magnesie ; Sp. Carbonato de magnesia. (MgC03)4.Mg(0H)2 + 6H20 ;* 522. White, bulky, pulverulent masses, commonly in square cakes, or a light, white powder, smooth to the touch, and nearly insolu- ble in water, but soluble with effervescence in dilute acids, yield- ing limpid, colorless solutions ; these, after the addition of a little solution of ammonium chloride, are not precipitated upon slight supersaturation with ammonia-water, but, upon the subsequent addition of sodium phosphate, afford a white crystalline precipi- tate of ammonio-magnesium phosphate. It is also soluble in solutions of the alkaline carbonates, potassium chloride, sulphate, and nitrate, borax, and particularly in solutions of ammonium salts, with the formation of soluble double salts. Magnesium carbonate is decomposed at a red heat, and also by all acids, and by the fixed alkaline hydrates. 100 parts of it, when ignited at a red heat until the weight remains constant, should leave a residue of magnesium oxide amounting to at least 40 parts. Examination: A small portion (about 1 gram) of the powdered magnesium carbonate is mixed and agitated with about 20 times its weight of warm water, and filtered ; the filtrate is tested with turmeric paper, and, if this becomes brown, alkaline carbonates are indicated ; when * The composition of magnesium carbonate differs somewhat according to the method of preparation. Although the commercial article usually corre- sponds to the above formula, the amount of water varies between 4 and 6 mole- cules. MAGNESIUM. 423 a few drops of the filtrate are evaporated upon platinum-foil, only a very slight residue should remain. The magnesium carbonate left on the filter is rinsed into a flask, by means of a wash-bottle, the mixture warmed, and sulphuric acid added, drop by drop, until solution is effected; a remaining slight turbidity would indicate traces of silicic acid. The solution is filtered, if neces- sary, and saturated with hydrogen sulphide, when a dark colora- tion or precipitate will indicate lead or copper ; after filtration, if necessary, the liquid is rendered alkaline by the addition of am- monia-water ; an ensuing black precipitate would indicate salts of iron; a light reddish one, salts of manganese ; a white one, salts of aluminium or zinc (the incidental presence of phosphates would also give a white precipitate). In order to distinguish the latter, the precipitate is washed, subsequently dissolved in a little dilute hydrochloric acid, and, after gently heating to expel the hydrogen sulphide, the solution is supersaturated with ammonia-water; the aluminium is thereby precipitated, while zinc remains in solution, and may be recognized by re-precipitation with hydrogen sulphide or ammonium sulphide. The ammoniacal filtrate is then tested with a few drops of ammonium oxalate; a white precipitate, insoluble upon the addi- tion of ammonium chloride, would indicate salts of calcium. The latter may be further specially tested for, if required, by igniting a portion of the magnesium carbonate, extracting with water and filtering, and, after the addition of a little ammonium chloride and ammonia-water, testing the filtrate with ammonium oxalate. Chlorides and sulphates may be detected, in the diluted solution of the magnesium carbonate in diluted nitric acid, by testing the same in separate portions, with barium nitrate for sulphates, and with argentic nitrate for chloride. MAGNESII SULPHAS. MAGNESIUM SULFURICUM. Epsom Salt. Sulphate of Magnesium. Magnesium Sulphate. Ger. Scliwefelsaures Magnesium, Bittersalz ; Fr. Sulfate de magnesie ; Sp. Sulfato de magnesia. Colorless, transparent, four-sided rhombic prisms (Fig. 136), but usually met with in commerce as small, acicular needles ; they con- tain seven molecules (51.22 per cent.) of water of crystallization, six of which are eliminated at 120° C. (248° F.), while the last molecule is not expelled at temperatures below 2203 C. (428° F.); the crystals do not effloresce at common temperatures and in ordi- MgS04 + 7H20; 246. 424 MANUAL OF CHEMICAL ANALYSIS. nary atmospheric humidity, but they do so slowly in warm, dry air. When heated, they lose their water of crystallization with- out previously undergoing aqueous fusion, and at a red heat undergo igneous fusion, with partial decom- position. Magnesium sulphate is soluble in 0.8 part of water at 15° C. (59° F.), and in 0.15 part of boil- ing water, but is insoluble in alcohol; its aque- ous solution has a nauseous, bitter taste, and is neutral in its action upon litmus; it is decom- posed, and gives white precipitates, with the fixed alkaline hydrates and carbonates, and also with the earthy hydrates and their soluble salts; ammonia-water and ammonium carbonate, how- ever, do not at once cause a precipitate in dilute solutions of magnesium sulphate, or, if so, but a very slight one, since ammonium salts when present, or when formed by the neutralization of acidulous solutions, act as a solv- ent for magnesium hydrate or carbonate, and thereby retard or prevent their precipitation; but, on the subsequent addition of phosphoric acid or solutions of tri-basic phosphates, a complete precipitation takes place, which precipitate, however, is soluble in dilute acids. The crystals of magnesium sulphate are isomorplrous with those of zinc sulphate, and cannot be distinguished from them by the eye; it is easy, however, to discriminate between them, not only by the difference in taste, but also by the action of a few drops of ammonium sulphide or solution of potassium ferrocyanide on their aqueous solutions; that of magnesium sulphate remains unaffected by these reagents, whereas solution of zinc sulphate yields, in either instance, a white precipitate. Examination: Metallic impurities may be detected in the solution of the salt, acidulated with hydrochloric acid, by the occurrence of a turbidity or precipitate upon saturation with hydrogen sulphide (an ensuing white turbidity may be due simply to sulphur, a lemon-yellow one will indicate arsenic), and, after filtration, if necessary, and neutralization with ammonia-water, by the subsequent addition of ammonium sulphide; a white precipitate with the latter re- agent would ind cate zinc; when a dark precipitate is formed, both with the hydrogen sulphide and ammonium sulphide, cop- per and iron are indicated, and may be confirmed in the slightly acidulated solution of the salt, the former by a reddish-brown pre- cipitate, the latter by a blue one, with potassium ferrocyanide. Alkaline sulphates may be detected by triturating 2 parts of the magnesium sulphate with an equal weight of dry calcium hydrate (from which any free alkali must have been previously removed by washing with water, and again drying), and adding this mix- Fig. 136. MAGNESIUM. 425 ture to a mixture of 10 parts of alcohol and 10 parts of water. The mixture is then allowed to stand for about two hours, with frequent agitation, when 40 parts of absolute alcohol are added, and, after active agitation, the mixture poured upon a filter which has been previously moistened with alcohol. If an alkaline sul- phate be present in the magnesium sulphate, it will be contained in the alcoholic filtrate in the form of hydrate, and may then readily be detected by its action upon turmeric paper; if litmus paper be employed, the alcoholic liquid should be mixed with a little water, and the alcohol dissipated by the aid of heat before the application of the test. Ammonium salts may be detected by the odor of ammonia, when a little of the salt is heated, in a test-tube, with a strong solution of potassium hydrate, or by the development of white fumes when a glass rod, moistened with acetic acid, is held over the orifice of the tube. Aluminium and Calcium Salts.—'The former may be detected in the solution of magnesium sulphate, to which a sufficient amount of ammonium chloride has been added, by the formation of a colorless, flocculent precipitate on the addition of ammonia-water; and the latter by a white precipitate on the addition of ammonium oxalate. Chlorides «may be detected in the diluted solution of the salt, acidulated with nitric acid, by a white turbidity on the addition of solution of argentic nitrate. Estimation: One hundred parts of magnesium sulphate, dissolved in boiling water, and completely precipitated by a boiling solution of sodium carbonate, yield a precipitate which, when washed, dried, and ignited at a red heat, weighs 16.26 parts. The quantitative estimation of magnesium in magnesium sul- phate is, however, usually effected by its precipitation as ammonio- magnesium phosphate, and the conversion of the latter, by ignition, into magnesium pyrophosphate; from the weight of the latter, the amount of magnesium oxide, or the corresponding amount of crystallized magnesium sulphate may readily be calculated. To the aqueous solution of a weighed amount of the salt, ammonium chloride and ammonia-water are added, and subsequently solution of sodium phosphate until no further precipitate is produced; the mixture is allowed to stand for ten or twelve hours, when the precipitate is collected upon a filter, washed with a mixture of about one part of ammonia-water and three parts of water, and, when dry, completely incinerated in a porcelain crucible. Of the residue of magnesium pyrophosphate, Mg2P207, thus obtained, 100 parts correspond to 36.03 parts of magnesium oxide, MgO, or 221.62 parts of crystallized magnesium sulphate, MgS04+- 7II20. 426 MANUAL OF CHEMICAL ANALYSIS. MAGNESII SULPHIS. Sulphite of Magnesium. Magnesium Sulphite. MAGNESIUM SUL EUROSUM. Ger. Schwefligsaures Magnesium ; Fr. Sulfite de magnesie; Sp. Sulfito de magnesia. MgSOj4- 6H20; 212. A white, crystalline powder, containing 6 molecules (50.94 per cent.) of water of crystallization; it is odorless, but possesses a slightly bitter, somewhat sulphurous, taste, and a neutral or slightly alkaline reaction; on exposure to the air, it gradually absorbs oxygen, and becomes converted into magnesium sulphate. When heated to 200° C. (392° F.), the salt loses its water of crys- tallization, and becomes decomposed, being converted into mag- nesium oxide and anhydrous magnesium sulphate. Magnesium sulphite is soluble in 20 parts of water at 15° C. (59° F.), and in 19 parts of boiling water ; it is insoluble in alcohol. The aqueous solution, when mixed with solution of ammonium chloride and ammonia-water, yields, upon the subsequent addition of solution of sodium phosphate, a white crystalline precipitate, which is insoluble in water or dilute but readily soluble in acids. Magnesium sulphite is also completely soluble in 4 times its weight of dilute hydrochloric acid, with the development of the odor of burning sulphur, but without producing any turbidity (distinction from magnesium hyposulphite). A 1 per cent, aque- ous solution of the salt, strongly acidulated with hydrochloric acid, should not afford more than a slight cloudiness on the ad- dition of solution of barium chloride (absence of and distinction from magnesium sulphate). MANGANUM HYPEROXYDATUM. MANGANE3IUM OXYDATUM NATIVUM. MANGANI OXIDUM NIGRUM. Black Oxide of Manganese. Pyrolusite. Manganese Dioxide. Ger. Mangansuperoxyd, Braunstein ; Fr. Oxyde de manganese ; Sp. Peroxido de manganeso. Heavy, compact masses, of a dull-black or brownish-black, earthy appearance, or masses of acieular or rhombic crystals of a black, metallic lustre, and, if pure pyrolusite, of a spec. grav. of 4.9. In commerce, it occurs usually ground, as a coarse, dull, Mn02; 86. MANGANUM. 427 black powder, consisting of manganese dioxide, sesqui-oxide, and monoxide, and is contaminated with the gangue (quartz, felspar, barytes, limestone, etc.), which frequently amounts to 40 or 50 per cent. Manganese dioxide is infusible, permanent in the air, and in- soluble in water or alcohol. When exposed to a strong red heat, it loses one-third of its oxygen, and is converted into reddish- brown mangano-manganic oxide, Mn304: 3Mn02= Mn304-|-02. It is not attacked by cold concentrated sulphuric acid, but, upon heating with the latter, it is converted into manganous sul- phate, with the evolution of oxygen : Mn02 + II2S04 = MnS04q- h2o+o. If, however, oxalic acid, or other readily oxidizable organic substances are present, manganese dioxide is also dissolved by dilute sulphuric acid, with the evolution of carbon dioxide : Mn02 + H2S04 + C2H204 = MnS04 + 2C02 -f 2H20. When heated with hydrochloric acid, it is converted into man- ganous chloride, with the development of chlorine : Mn02 + 4HC1 = Mn01a + 2HaO -t- Cl2. The resulting brownish solution, when filtered and neutralized with ammonia-water, yields, with hydrogen sulphide or ammo- nium sulphide, a flesh-colored precipitate of manganous sulphide ; the color of this precipitate is, however, frequently rendered darker, or even brownish-black, by the presence of oxides of iron and other metals. When a small portion of manganese dioxide is mixed with about an equal weight of potassium hydrate and a little potas- sium nitrate or chlorate, and the mixture heated to redness upon platinum-foil, it yields a dark green mass, which dissolves in water with a green color, changing to purple when the solution is boiled or on the addition of dilute sulphuric acid. Examination: As manganese dioxide is frequently employed in connection with potassium chlorate for the generation of oxygen gas, its per- fect freedom from organic contaminations should be conclusively established, as the latter may give rise to violent and dangerous explosions. The presence of organic impurities in general may be determined by strongly heating a little of the powdered manga- nese dioxide in a glass tube, when no combustion should take place, nor should carbonic acid gas be evolved. Black antimonious sulphide, which, by accident or through care- lessness, may become mixed with or substituted for manganese dioxide, may be readily detected bjr the development of the odor of hydrogen sulphide in contact with dilute hydrochloric acid, and, after boiling with the latter, and filtering, by the production of an orange-colored prec'pitate upon saturation with hydrogen sulphide. 428 MANUAL OF CHEMICAL ANALYSIS. Since, however, the value of commercial black oxide of manga- nese or pyrolusite, for most of its applications in the arts and trades, depends less upon the nature of its impurities than upon the percentage of real manganese dioxide, an examination of the mineral is invariably required before its ap- plication, and is mainly d rected-to the deter- mination of the amount of dioxide. Among the several methods of conducting the assay, the two following are simple and accurate, the one being an approximate, the other a quantitative one : I. Five grams of the finely powdered black oxide of manganese are added, in a small flask (Fig. 137), to a solution of 21 grams of crystallized or granular ferrous sulphate in 15 grams of water and 45 grams of hy- drochloric acid, and, when mixed by gentle agitation, the whole is heated for a few minutes to boiling; after being allowed to cool, the liquid is filtered, and the filtrate subsequently tested with potassium ferricyanide; if it gives no blue precipitate, the test bears evidence that the pyrolusite contains at least 66 per cent, of real manganese dioxide; if a blue precipitate is produced, the peroxide is wanting in that strength in proportion to the amount of the precipitate. II. Three grams of the black oxide of manganese, in fine pow- der, and previously dried at about 120° C. (248° F.), are care- fully introduced into the flask K' (Fig. 138) of the little apparatus described on page 86, into which previously has been poured suf- ficient of a mixture of 1 part of concentrated sulphuric acid and 2 parts of water to fill the flask to about one-third of its capacity. The apparatus is then brought upon the balance, and, together with from 8 to 9 grams of pure crystallized oxalic acid, is accu- rately weighed. The oxalic acid is then added to the mixture, being careful to avoid any loss, the cork carrying the tubes is adjusted, and the ensuing reaction effected by gentle agitation ; the flask K is charged with a little concentrated sulphuric acid, through which the evolved carbonic acid gas has to pass, and which absorbs and retains the moisture; gentle heat is applied to the flask K', as long as a brisk evolution of gas takes place; the process is completed when this action and Fig. 137. Fig. 138. MANGANUM. 429 the passage of gas-bubbles through the sulphuric acid both cease, and the black color of the mixture has changed to a more or less brown one; the residual gas is then driven off, by momentary ebullition, and the apparatus again weighed. Every two mole- cules of carbonic acid evolved correspond to one molecule of manganese dioxide decomposed ; the molecular weight of the latter (87) being so nearly equal to twice that of carbonic acid (44), that the loss of weight suffered by the apparatus may be taken to represent the quantity of real manganese dioxide in the 8 grams of the sample employed; and it has only to be divided by 3 and multiplied by 100 in order to express the percentage. MANGANI SULPHAS. MANGANUM SULFURICUM. Ger. Scliwefelsanres Mangan ; Fr. Sulfate tie manganese ; Sp. Sulfato de manganeso. Sulphate of Manganese. Manganous Sulphate. Colorless or pale rose-colored prismatic crystals, occurring in three different forms, with different quantities of water of crys- tallization: (1) Monoclinic prisms (isomorphous with ferrous sul- phate), containing seven molecules of water of crystallization, and obtained when crystallized at a temperature below 6° C.(42.8° F.); (2) Triclinic prisms (isomorphous with cupric sulphate), contain- ing five molecules of water of crystallization, obtained when crystallized at a temperature between 7° and 20° C. (44.6° and 68° F.); and (8) Quadratic crystals or large monoclinic prisms, containing four molecules of water of crystallization, and obtained when crystallized between 20° and 30° C. (68° and 86° F.). The latter salt is the one commonly met with. The crystals are permanent in the air, though slightly efflorescent in air that is dry and warm; they are soluble in 0.8 part of water at, 15° C. (59° F.), and in 1 part of boiling water, but insoluble in alcohol; the aqueous solution is neutral and colorless, or has, when con- centrated, a faint rose-color; its taste is astringent, and it affords, with the alkaline hydrates and carbonates, white precipitates, of which those with the hydrates gradually become yellow, and finally dark-brown, by oxidation; ammon am sulphide produces a flesh-colored precipitate soluble in dilute mineral acids, and also in acetic acid (distinction from zinc); tannic acid or tincture of nutgall does not act upon the solution ; potassium ferroeyanide pro- duces a reddish-white prec'pitate, and potassium ferricyanide a MnS04 + 4II20s 222. 430 MANUAL OP CHEMICAL ANALYSIS. brown one; with barium nitrate or chloride it yields a white pre- cipitate, insoluble in hydrochloric acid. When a fragment of a crystal of manganous sulphate is heated with one or two drops of solution of potassium hydrate and a little potassium chlorate or nitrate, upon platinum-foil, it yields a bluish-green fuse. Examination: Ferrous and .cupric sulphates are detected, in the diluted solu- tion, acidulated with hydrochloric acid, the former by a blue precipitate with potassium ferrocyanide, the latter bv a reddish- brown one with the same reagent, or a black one with sulphide. Magnesium and alkaline sulphates may be detected by com- pletely precipitating the dilute solution of the salt with ammonium sulphide, and by testing part of the filtrate with sodium phos- phate ; a white, crystalline precipitate will indicate magnesium sulphate: if no reaction has taken place, another portion of the filtrate is evaporated in a porcelain capsule, and the residue heated to redness upon platinum-foil; a fixed remainder would indicate potassium or sodium salts. MORPHINA, MORPHIUM. MORPHINUM. Morphine. Morphia. Ger. Morpliin ; Fr. Morphine ; Sp. Morfina. C17H16N03.H20; 303. Small, brilliant, prismatic crystals, transparent and colorless, or a white, crystalline powder, containing one molecule (5.94 per cent.) of water of crystallization. When heated to 120° C. (248° F.), the crystals lose their water of crystallization and become opaque, and, when cautiously further heated, they melt without decom- position, assuming a crystalline form on cooling; at temperatures above 200° C. (892° F.), they become decomposed and blackened, and, when strongly heated on platinum-foil, they burn away, leav- ing a carbonaceous residue, which is wholly dissipated at a red heat. Morphine is but sparingly soluble in cold water, requiring at 15° C. (59° F.) 1000 parts of the latter for solution, but is soluble in 500 parts of boiling water, in 100 parts of alcohol at 15° C. (59° F.), and in 86 parts of boiling alcohol; it is very sparingly soluble in ether and chloroform, and insoluble in benzol, petroleum benzin, and carbon bisulphide (distinction from narcotine and co- deine), but is quite readily soluble in hot amylic alcohol; it dissolves MORPH INA. 431 freely in dilute acids, in the fixed alkaline hydrates, and in lime- water, but is almost insoluble in ammonia-water; its alkaline solu- tions gradually absorb oxygen and become decomposed, acquiring thereby a brown color. The aqueous solution of morphine, and the alcoholic solution to a still greater extent, possess a bitter taste and an alkaline reaction. A solution of morphine in acidulated water, if not too dilute, affords upon the addition of a solution of potassium or sodium hydrate, ammonia-water, sodium carbonate or bicarbonate, a white crystalline precipitate of morphine, which, however, is readily soluble in an excess of potassium or sodium hydrate, but very sparingly soluble in ammonia-water; it is not precipitated by tan- nic acid, but affords a white precipitate with potassio-mercuric iodide, and a brown one with iodinized potassium iodide. In addition to the above described characters, morphine may be recognized and distinguished from all other alkaloids by the fol- lowing specific reactions and tests: Strong sulphuric acid dissolves morphine without coloration, but if the solution be quite strongly heated, and, after being allowed to cool, a drop of diluted nitric acid added, the liquid as- sumes a deep blood-red color; if the solution in sulphuric acid, after heating and being again allowed to cool, be diluted with water, and a fragment of potassium bichromate added, an intense ma- hogany-brown color is produced. With concentrated nitric acid, morphine produces a blood-red color, which gradually changes to yellow; this coloration, however, is not changed to violet by the addition of stannous chloride or ammonium sulphide (distinction from brucine). If morphine or its salts be intimately mixed with about four times its we.ght of cane-sugar, and the mixture added to concentrated sulphuric acid, a dark red coloration is produced ; if the amount of alkaloid be very small, the mixture will assume a wine-red or rose-red color. If to a trace of morphine or its salts a freshly prepared solution of molybdic acid or ammonium molybdate in concentrated sulphuric acxl be added, a fine violet color is soon produced, which afterwards changes to blue, then to a dirty-green, and finally disappears; by the addition of water the coloration is immediately destroyed. A particularly character- istic reaction of morphine or its salts, when free from other reducing substances, consists in adding a few drops of its solution to a solution of iodic acid, whereby iodine is liberated, imparting a yellowish or brownish color to the solution; if then a few drops of chloroform or carbon bisulphide be added, and agitated with the liquid, the iod.ne will be absorbed, with a fine violet or purple color; and by the employment of a few drops of mucilage of starch instead of chloroform or carbon bisulphide, a fine deep blue color will be produced. If morphine or a perfectly neutral solu- tion of one of its salts be brought in contact with a few drops of a diluted neutral solution of ferric chloride, a blue color is produced ; 432 MANUAL OF CHEMICAL ANALYSIS. this reaction is very characteristic, as being produced by no other alkaloid, but the color is destroyed'or will not be produced in the presence of free acids or alcohol. If to a diluted solution of potassium ferricyanide a drop of a solution of ferric chloride be added, and subsequently a drop of a solution of morphine or its salts, a deep blue coloration or precipitate will be produced. Examination: Narcotine is indicated by a white, crystalline residue, left upon evaporating, on a watch-glass, a little pure ether which lias been agitated with a small portion of the morphine. Inorganic impurities or admixtures may be detected by a fixed residue, upon complete incineration of a little of the morphine on platinum-foil, as well as by their insolubility, when a small por- tion of morphine is dissolved in about fifty times its weight of boiling alcohol. For the separation of morphine from other alkaloids or complex organic principles with which it may be associated, see page 111. MORPHINiE ACETAS. MORPHIUM SEU MORPHINUM ACETICUM. Acetate of Morphine or Morphia. Morphine Acetate. Ger. Essigsaures Morphin ; Fr. Acetate de morphine ; Sp. Acetato de morfina. CI7H19N03.C2H402 + 3Ha0; 399. A white or yellowish-white, indistinctly crystalline or amor- phous powder, having a faintly acetous odor, and containing 3 molecules (13.5 per cent.) of water. It gradually loses water and acetic acid on exposure to the air, and, when heated at 100° C. (212“ F.), rapidly loses the entire amount of water, and acquires a brown color; when heated upon platinum-foil, it fuses, and is wholly dissipated at a red heat. It remains colorless when moist- ened with concentrated sulphuric acid, with the evolution of vapors of acetic acid, and dissolves in concentrated nitric acid, with a scarlet-red color. Morphine acetate, when freshly prepared, is soluble in 12 parts of water, and in 68 parts of alcohol at 15° C. (59° F.); when kept for some time, however, it requires, in consequence of the loss of acetic acid, a larger amount of watef for complete solution, unless a few drops of acetic acid be added. It is also soluble in 1.5 parts of boiling water, in 60 parts of chloroform, and freely soluble in diluted acids, but is insoluble in ether and petroleum benzin; it is decomposed by the action of boiling alcohol, and, upon the sub- sequent add.tion of water, a precipitate of morphine is produced. MORPHINA. 433 Its saturated aqueous solution has a bitter taste, and is neutral, or possesses but a slightly acid reaction; it is rendered turbid by tannic acid, but becomes transparent again upon the addition of an excess of the reagent (evidence of the absence of narcotine) ; it is not permanently precipitated bv potassium hydrate, when added in slight excess (distinction from most alkaloids), and assumes a greenish-blue color with a dilute neutral solution of ferric chloride. In its general behavior toward reagents, mor- phine acetate corresponds to the tests for morphine, as described under the latter, on page 431. Examination: Morphine acetate should be completely soluble in 40 parts of water, leaving at most but a slight residue, which should respond to the tests for pure morphine ; and when strongly heated on pla- tinum-foil should be completely dissipated. Sulphates and chlorides may be detected in the aqueous solution of the salt, acidulated with diluted nitric acid, when tested with barium nitrate or chloride for the former, and with argentic nitrate for the latter. MORPHINiE HYDROCHLORAS. MORPHIUM SEU MORPHINUM HYDROCHLORICUM. MORPHINE Hydro chlorate of Morphine or Morphia. Morphine Hydrochlorate. MURIAS. Ger. Chlorwasserstoffsaures Morpliin ; Fr. Chlorhydrate de morphine ; Sp. Hidroclorato de morfina. C17HJ9N03.HC1 + 3H20; 375.4. White, flexible, acicular crystals, of a silky lustre, or larger transparent prisms, containing 3 molecules (14.4 per cent.) of water of crystallization, and permanent in the air. When heated to 130° C. (266° F.), the salt loses its water of crystallization, and when heated upon platinum-foil, it first fuses, and afterwards, at a higher temperature, burns away without residue. Morphine hydrochlorate is soluble in 24 parts of water and in 63 parts of alcohol at 15° C. (59° F.); in about 0.5 part of boiling- water and 31 parts of boiling alcohol ; and is also soluble in 20 parts of glycerin, but insoluble in ether. Its aqueous solution is neutral, has a bitter taste, and assumes a yellowish-red color upon the addition of strong nitric acid, and a bluish one with a dilute neutral solution of ferric chloride; it affords no permanent turbidity with solution of potassium hydrate, when added in slight excess, but is precipitated by ammonia-water; with tannic acid it affords a slight turbidity, which disappears on the addition of an excess of the reagent; and with argentic nitrate it gives a white, 434 MANUAL OF CHEMICAL ANALYSIS. curdy precipitate, insoluble in nitric acid, but soluble in ammonia- water, which solution, when heated in a test-tube, separates metallic silver. When a little dry morphine hydrochlorate is added to a mix- ture of two parts of concentrated sulphuric acid and one part of water, in a small test-tube, no change of color of the liquid takes place, either at common temperatures, or when gently warmed by immersing the test-tube in hot water (evidence of the absence of salicin and other bitter substances); when this liquid is divided into two portions, and one drop of strong nitric acid is added to the one part, a red coloration occurs, and on adding a trace of potassium bichromate to the other part, only a slight yellowish- green coloration takes place. Morphine hydrochlorate dissolves in chlorine-water, with a yellowish color, which becomes brown upon the addition of am- monia-water (distinction from quinine, which yields an emerald- green color). In its general behavior toward re-agents, mor- phine hydrochlorate corresponds to the tests for morphine, as described under the latter, on page 431. MORPHIUM SEU MORPHINUM SULFURICUM. MORFHINiE SULPHAS. Sulphate of Morphine or Morphia. Morphine Sulphate. Ger. Schwefelsaures Morpliin ; Fr. Sulfate de morphine ; Sp. Sulfato de morfina. (C17H19N03)2.H2S04+5H20; 758. White, fasciculate, feathery crystals, of a silky lustre, contain- ing 5 molecules (11.87 per cent.) of water of crystallization, and permanent in the air. When heated to 180° C. (266° F.), the salt loses its water of crystallization, and, when strongly heated on platinum-foil, burns entirely away without residue. Morphine sulphate is soluble in 24 parts of water and in 702 parts of alcohol at 15° 0. (59° F.), and in about 0.5 part of boiling water and 31 parts of boiling alcohol (distinction from quinine sulphate); it is almost insoluble in ether and in chloroform. Its aqueous solution is neutral and very bitter; it gives no perma- nent precipitate with potassium hydrate when added in slight excess, but yields with ammonia-water and the alkaline carbonates and bicarbonates a white crystalline precipitate of morphine. It affords a blue color with a dilute, neutral solution of ferric chlo- ride, and a white precipitate, insoluble in acids, with barium chloride. Morphine sulphate dissolves in strong sulphuric acid without MORPHINA. 435 coloration, even when gently warmed by dipping the test-tube in warm water (evidence of the absence of salicin and other bitter glucosides); it dissolves in concentrated nitric acid with a yellow- ish-red coloration (distinction from quinine). When dissolved in a little chlorine-water, morphine sulphate yields a greenish-yellow solution, which becomes dark-brown upon the addition of ammo- nia-water (further distinction from quinine, which yields an emerald-green color). In its general behavior toward reagents, morphine sulphate corresponds to the tests for morphine, as de- scribed under the latter on page 481. Examination: Sodium sulphate, which has been found to occur as an adulterant of morphine sulphate, may be detected, as well as other inorganic salts, by a non-volatile residue, when a little of the morphine sulphate is strongly heated on platinum-foil. Ammonium salts may be recognized by the odor of ammonia, when a little of the salt is heated, in a test-tube, with a strong solution of potassium hydrate; and by the formation of white fumes, when a glass rod, moistened with acetic acid, is held over the orifice of the tube. Morphiometric Assay of Opium: Since the therapeutical and commercial value of opium mainly depends upon the quantity of morphine which it contains, an ex- amination of opium is invariably required before its introduction into the market or its application for the manufacture of the opium alkaloids, or for medication. Among the various methods for the estimation of the morphine strength of opium, the follow- ing are simple in execution, require comparatively little time, and render approximately correct results. I. Fluckiyer's Process. — Eight grams of powdered air-dry opium are digested for twelve hours, with frequent agitation, with 80 grams of cold water, and subsequently filtered. 42.5 grams of the filtrate (representing the soluble matter of one-half of the opium employed) are then brought into a tared flask, and to the solution 12 grams of alcohol, of about 0.820 spec, grav., and 10 grams of ether are added, whereby no turbidity should ensue; a portion of the ether forming a colorless layer on the surface of the mixture. 1.5 grams of ammonia-water, spec. grav. 0.960, are then added, and, after thorough agitation, the mixture allowed to repose for 24 hours, when the morphine will be deposited in white crystals. The crystals of the alkaloid are afterwards col- lected on a folded double filter having a diameter of about 10 centimeters (four inches), the flask rinsed with 10 grams of a mixture of equal parts of alcohol and ether, and finally with 10 grams of pure ether, and these liquids gradually poured on the crystals of morphine in order to wash them. The crystals are subsequently cautiously pressed between the folds of the two filters, which will almost completely absorb the mother liquor 436 MANUAL OF CHEMICAL ANALYSIS. which the crystals of morphine may still retain. The alkaloid may now readily be removed from the filter, and having been brought into the tared flask, which may still contain a few crys- tals of morphine attached to its sides, the whole is dried at 100° C. (212° F.), and its weight determined. From the weight of the alkaloid, which, at 100° C. (212° F.), corresponds to the formula C17H]QN03+ H20, the percentage of morphine may be calculated. As by the above method a small amount of morphine remains dissolved in the liquid from which it has separated, the error which would thereby be occasioned may be eliminated by adding 0.088 gram to the amount of alkaloid obtained. As a test for the purity of the crystals obtained, they should, although slowly, be completely soluble in 100 times their weight of officinal lime- water. An air-dried opium, of good quality, when submitted to the above method of examination, should yield from 0.40 to 0.48 gram of alkaloid, corresponding to from 10 to 12 per cent, of pure morphine. II. Squibb''s Modification of FlucJciger's Process. — Ten grams (154.32 grains) of commercial opium, in its moist or powdered condition, and representing the average quality of the specimen, are brought into a flask or wide-mouthed bottle of 120 cubic centimeters (4 fluidounces) capacity, which has been previously weighed and fitted with a good cork: 100 cubic centimeters (3.3 fluidounces) of water are then added, and the mixture well shaken. It is then allowed to macerate over night, or for about twelve hours, with occasional shaking, and then, after shaking well, the magma is transferred to a filter of about 10 centimeters (4 inches) diameter, which has been placed in a funnel and well wetted. The solution is now filtered into a tared or marked vessel, and the residue on the filter percolated with water dropped on to the edges of the filter and the residue until the filtrate measures about 120 cubic centimeters (4 fluidounces), and this strong solution set aside. The residue is then returned to the flask or bottle by means of a very small spatula, without breaking or disturbing the filter in the funnel, 30 cubic centimeters (1 fluidounce) of water added, the mixture well shaken, and the magma returned to the filter. After being allowed to drain, the bottle is rinsed twice, each time with 10 cubic centimeters (0.33 fluidounce) of water, and the rinsings poured upon the residue. When this has passed through, the filter and residue are washed with 20 cubic centimeters (0.66 fluidounce) of water, applied drop by drop around the edges of the filter and upon the contents. This (1204- 70) 190 cubic centimeters (6.33 fluidounces) of total solu- tion will practically exhaust almost any sample of 10 grams of opium ; but occasionally a particularly rich opium, or one in coarse powder, or an originally moist opium which has by slow drying become hard and flinty, will require further exhaustion. MORPHINA. 437 In all such cases, or cases of doubt, the residue should be again removed from the filter and shaken with 30 cubic centimeters (1 fluidounce) of water, and returned and again washed as before. The filter and residue are now dried at 100° C. (212° F.) until the}7 cease to lose weight; and if any residue remains in the bot- tle, the bottle is also to be dried in an inverted position, and weighed. The weaker solution is then evaporated in a tared capsule of about 200 cubic centimeters (6.6 fluidounces) capacity, without a stirrer, on a water-bath, until reduced to about 20 grams (309 grains), the 120 cubic centimeters of stronger solution subsequently added, and the whole again evaporated to about 20 grams (309 grains). The capsule and contents are cooled, and, when cool, 5 cubic centimeters (0.17 fluidounce) of alcohol, spec, grav. 0.820, added, and the mixture stirred until a uniform solu- tion is obtained and no adhering extract remains undissolved on the capsule. If this solution should contain an appreciable pre- cipitate, it must be filtered, the filter carefully washed, and the filtrate evaporated to 25 or 30 grams. The concentrated solution from the capsule is poured into a tared flask of about 100 cubic centimeters (3.33 fluidounces) capacity, the capsule rinsed with about 5 cubic centimeters of water, used in successive portions, and the rinsings added to the contents of the flask. If the solu- tion has not required filtering, then 5 cubic centimeters (0.17 fluidounce) more of alcohol are added; if it has been filtered and evaporated, 10 cubic centimeters (0.33 fluidounce) of alcohol are added and shaken well. Then 30 cubic centimeters (1 fluidounce) of ether are added, and again shaken well. Four cubic centi- meters (0.133 fluidounce) of ammonia-water, spec. grav. 0.960, are now added, the flask shaken vigorously until the crystals begin to separate, then set aside in a cool place for 12 hours, that the crystallization may be completed. The ethereal stratum is poured oft' from the flask, as closely as possible, on to a tared filter of about 10 centimeters (4 inches) diameter, which has been well wetted with ether, 20 cubic cen- timeters (0.66 fluidounce) of ether added to the contents of the flask, which is rinsed around without shaking, and the ethereal stratum again poured off as closely as possible on to the filter, keeping the funnel covered. When the ethereal solution has nearly all passed through, the edges and sides of the filter are washed with 5 cubic centimeters 70.17 fluidounce) of ether, and the filter allowed to drain with the cover off. The remaining contents of the flask are then placed on the filter, and the funnel covered. When the liquid has nearly all passed through, the flask is rinsed twice with two portions of water of 5 cubic cen- timeters (0.17 fluidounce) each, pouring the rinsings with all the crystals that can be loosened on to the filter, the flask dried in an inverted or horizontal position, and, when thoroughly dried, weighed. The filter and crystals are then washed with 10 cubic 438 MANUAL OF CHEMICAL ANALYSIS. centimeters (0.33 fluidounce) of water, applied drop bj7 drop to the edges of the filter, and, when drained, the filter and con- tents removed from the funnel, the edges of the filter closed together, and the filter compressed gently between many folds of bibulous paper. It is then dried at 100° C. (212° F.) and weighed, the crystals of morphine removed from the filter, and the latter brushed off and reweighed, to get the tare to be subtracted. The remainder, added to the weight of the crystals in the flask, will give the total yield of morphine, in clean, distinct, small, light- brown crystals. As .a test of purity for the obtained morphine, 0.1 gram of the finely powdered crystals should be completely soluble in 10 cubic centimeters of officinal lime-water. III. United States Pharmacopoeia Process.—Seven grams of opium (in any condition to be valued) are triturated, in a mortar, with 3 grams of freshly slaked lime and 20 cubic centimeters of distilled water, until a uniform mixture results, after which 50 cubic centimeters of distilled water are added, and the mixture stirred occasionally during half an hour. It is then filtered through a plaited filter, having a diameter of 75 to 90 millimeters (3 to 3.5 inches), into a wide-mouthed bottle or stoppered flask (having a capacity of about 120 cubic centimeters and marked at 50 cubic centimeters) until the filtrate reaches this mark. To the filtered liquid (representing 5 grams of opium) 5 cubic centimeters of alcohol and 25 cubic centimeters of stronger alcohol are added, and, after shaking the mixture, 3 grams of ammonium chloride are added, the mixture again shaken well and frequently during half an hour, and then set aside for twelve hours. After coun- terpoising two small filters, one is placed within the other in a small funnel, and the ethereal layer decanted as completely as practicable upon the filter. Ten cubic centimeters of stronger ether are then added to the contents of the bottle and the mix- ture rotated, the ethereal layer again decanted upon the filter, and the latter afterward washed with 5 cubic centimeters of stronger ether, added slowly and in small portions. The filter is now allowed to dry in the air, and the liquid in the bottle poured upon it, in portions, in such a way as to transfer the greater por- tion of the crystals to the filter. The bottle is then washed,, and the remaining crystals transferred to the filter, with several small portions of distilled water, using not much more than 10 cubic centimeters in all, and distributing the portions evenly upon the filter. After allowing the filter to drain, it is dried, first by press- ing it between sheets of bibulous paper, and afterward at a tem- perature between 55 and 60° C. (131 to 140° F.). The crystals in the inner filter are now weighed, using the outer filter as a coun- terpoise. The weight of the crystals in grams, multiplied by 20, represents the percentage of morphine in the opium employed. The U. S. Pharmacopoeia directs that opium, in its normal, moist condition, should 3ueld not less than 9 per cent, of mor- NICOTINA. 439 pliine; and powdered opium not less than 12 nor more than 16 per cent, of morphine, when assayed by the above process. Morphiometric Assay of Tincture of Opium: When tincture of opium has to be examined for the quantity of morphine it contains, this may be ascertained by either of the following methods: I. To forty grams of the tincture (corresponding to 4 grams of powdered opium when prepared according to the United States and German Pharmacopoeias), contained in a tared flask, 1.5 cubic centimeters of ammonia-water, spec. grav.. 0.960, and 13 cubic centimeters of ether are added; after being well mixed by agita- tion the mixture is allowed to repose for at least thirty-six hours, when the crystals of morphine may be collected and further treated as described under Fluchiger's morphiometric process on page 435. To the amount of alkaloid obtained from the stated amount of tincture, about 0.1 gram should be added, as representing approxi- mately the amount of morphine remaining dissolved in the liquid from which it has been precipitated. The total weight of alka- loid should be not less than 0.48, nor more than 0.64 gram, indi- cating the employment of an opium containing not less than 12, nor more than 16 per cent, of morphine. II. One hundred and twenty cubic centimeters (4 fluidounces) of the tincture, or other liquid preparations, are evaporated at a low temperature to 10 grams (155 grains), and the process then conducted exactly as described under Sguibb's modified method of assay, on page 436, using, however, 5 cubic centimeters of alco- hol, instead of 10, and 2.5 to 3 cubic centimeters of ammonia-water, instead of 4 cubic centimeters. NICOTINA. NICOTIN UM. Nicotine. Nicotia. Ger. Nicotin ; Fr. Nicotine ; Sp. Nicotina. C H • 162 v-/10xx14 ’ 2 1 -Lu * A colorless or nearly colorless, oily, and volatile liquid, having the specific gravity 1.027 at 15° 0. (59° F.), a pungent odor, re- sembling that of tobacco, and an acrid, burning taste. By expo- sure to the air, it becomes gradually brown and thick; it begins to volatilize at 146° 0. (294.8° F.), and boils in an atmosphere of hydrogen at from 240 to 242° C. (464 to 467.6° F.); when heated on platinum-foil it volatilizes completely, forming irritating- vapors, which readily take fire, and burn with a bright, sooty 440 MANUAL OF CHEMICAL ANALYSIS. flame. When dropped into concentrated sulphuric acid, it dis- solves, with a red color, and, when one drop of solution of potas- sium bichromate is added, the solution becomes brown, and subsequently green; when mixed with hydrochloric acid and cautiously warmed, a reddish-brown mixture is formed, which, bv further evaporation and cooling, yields, upon the subsequent ad- dition of nitric acid, a violet coloration, gradually changing to orange. Nicotine produces white fumes with hydrochloric and acetic acids, precisely like ammonia-water; it sinks when dropped into water (distinction from coniine, which floats), but is miscible with water in all proportions, and becomes again separated on the addition of solid potassium or sodium hydrate; it also dissolves in alcohol, ether, amylic alcohol, carbon bisulphide, chloroform, petroleum benzm, and in most of the fixed and volatile oils; its solutions have an alkaline reaction, and an acrid, burning taste; they produce precipitates in solutions of neutral and basic plumbic acetate, cupric acetate, and many other metallic salts, and are pre- cipitated by solutions of tannic acid, potassio-mercuric iodide, iodinized potassium iodide, and auric and platinic chlorides, but the aqueous solution affords no precipitate with chlorine-water (additional distinction from coniine); the alcoholic solution should yield no turbidity with diluted sulphuric acid (evidence of the absence of ammonia). The aqueous solution of nicotine, when applied to the eye, causes the pupil alternately to dilate (mydri- asis) and to contract (stenocoriasis). By careful oxidation with concentrated nitric acid or potassium permanganate, nicotine is converted into nicotinic acid, C6H5N02 (Pyridine-carbonic acid, which may be obtained from its silver salt by decomposing it with hydrogen sulphide. Nicotinic acid forms colorless, needle-shaped crystals, which are readily soluble in alcohol and in boiling water, but not in cold water or in ether; they melt at 225° C. (437° F.), and, when heated with soda-lime, yield the volatile organic base, pyridine, C,,HSN. For the separation of nicotine from other alkaloids, or from complex organic mixtures with which it may be associated, see page 108. OLEUM AMYGDALA A1THEREUM. OLEUM AMYGDALARUM AMARARUM .ETHEREUM. Volatile Oil of Bitter Almond. Ger. Bittermandelol; Fr Essence d’amandes ameres ; Sp. Esencia de almendras amargas. A thin, colorless, or golden-yellow liquid, of great refractive power, and of the odor of bitter almonds. Exposed to the air, it OLEA 441 rapidly absorbs oxygen, with the formation of crystals of benzoic acid; its spec. grav. is from 1.060 to 1.070 at 15° C. (59° F.); or, after the removal of the hydrocyanic acid, 1.043 to 1.049 ; its boiling-point, 180° C. (356° F.). When dropped into water, oil of bitter almonds sinks, but dis- solves upon shaking, unless too much oil has been used, about 300 parts of water being required for solution. When a few drops of solution of potassium hydrate are added to its aqueous solution, and afterward one or two drops of a solution of a ferrous and a ferric salt, and finally, after agitation, a slight excess of hydro- chloric acid, there will appear a blue coloration, and, after a while, a blue precipitate. Oil of bitter almonds is miscible, in all proportions, with alco- hol, ether, chloroform, carbon bisulphide, and essential and fatty oils; it is also soluble in concentrated nitric acid, without color, and without the evolution of nitrous fumes; with an equal volume of concentrated sulphuric acid the mixture assumes a red color, which gradually increases in intensity, but remains limpid and clear. Oil of bitter almonds consists essentially of benz-aldehyde, or the aldehyde of benzoic acid, CfiH4-COH, together with usually from 2 to 5 per cent, of hydrocyanic acid, which, in the process of distillation, combine to form a very unstable compound. From this compound the acid is gradually liberated, and becomes par- tially converted, by its decomposition, into ammonium cyanide and formic acid. The crude oil, obtained by distillation without further rectification, usually contains the largest proportion of hydrocyanic acid. Examination: Alcohol may be detected in oil of bitter almonds by agitating it with three times its volume of concentrated nitric acid, and sub- sequently warming the mixture by dipping the test-tube into hot water. No reaction takes place with pure oil; but, if it has an admixture of more than three per cent, of alcohol, effervescence will occur, with disengagement of yellowish nitrous vapors. Chloroform, as well as alcohol, can be detected by submitting a small portion of the oil to distillation from a water-bath, cooling the receiving test-tube in ice-water (Fig. 139). The boiling- point of the oil being at 180° C. (356° F.), only admixtures vola- tile at or below the boiling-point of water will distil, with but small traces of the constituents of the oil. The obtained distillate is mixed with a little iodine-water; if chloroform be present, and no alcohol, it will absorb the iodine, and separate, with a rose- color. The colorless, aqueous liquid is decanted, and then warmed by dipping the test-tube in warm water; one drop of solution of iodinized potassium iodide is added, and then one drop of solu- tion of potassium hydrate, or sufficient nearly to decolorize the liquid. If alcohol be present, minute yellow crystals of iodoform 442 MANUAL OF CHEMICAL ANALYSIS. will be produced (Fig. 140), which, after subsiding, in a conical glass, may be recognized by the examination of the sediment under the microscope. Fig. 139. Nitrobenzol may be detected by adding 10 drops of the oil to a mixture of 5 cubic centimeters of alcohol and an equal volume ot water, in a narrow test tube, closing the tube with the finger, and effecting the mix- ture by gently inverting the tube. If the oil is pure, a perfectly clear solution will at once be produced, whereas, if it contains but one per cent, of nitrobenzol, the liquid will appear turbid from the separation of oily drops, which, upon gentle agitation, aggregate, and are deposited at the bottom of the tube. Another reliable test consists in adding to a portion of the oil, in a test-tube, a few fragments of metallic zinc, and a little diluted sulphuric acid. After standing for a couple of hours, or until the evolution of gas has ceased, the aqueous liquid is filtered through a wet filter, and to the filtrate a fragment of potassium chlorate and a drop of con- centrated sulphuric acid are added: no coloration should be thereby produced; a violet color would indicate the presence of nitrobenzol through its.reduction to aniline. Essential Oils.—Adulteration with cheaper essential oils, as well as with nitrobenzol, may be detected by the property of oil of bitter almonds to dissolve in a concentrated aqueous solution of sodium bisulphite when added drop by drop and agitated; whereas such admixtures remain undissolved, floating upon the aqueous solution after dilution with a little tepid water. Fig. 140. OLEA Estimation of the Available Quantity of Hydrocyanic Acid in Oil of Bitter Almonds: I. Five grams of the oil are mixed, in a beaker, with about 25 cubic centimeters of strong alcohol; then about 200 cubic cen- timeters of water and a few drops of solution of sodium chloride are added, and subsequently sufficient of a solution of potassium hydrate to render the liquid alkaline to test-paper, A decinormal solution of argentic nitrate (page 98) is then allowed to flow into the liquid from a burette until, with constant stirring, the pre- cipitate ceases to be re-dissolved, and therefore a slight permanent turbidity occurs. The number of cubic centimeters of argentic nitrate solution employed, multiplied by the decimal 0.0054, will represent the amount of hydrocyanic acid contained in 5 grams of the oil, and has only to be subsequently multiplied by 20 to express the percentage. * II. Another method consists in adding to 1 gram of the oil, contained in a small flask., about five times its weight of strong- alcohol, subsequently 45 cubic centimeters of distilled water, and finally a solution of 1 gram of pure crystallized argentic nitrate in an excess of dilute ammonia-water. The mixture is well agi- tated for a few moments, and subsequently pure nitric acid added until it acquires a slight acid reaction. The precipitated argentic cyanide is then carefully collected on a tared filter, thoroughly washed, and finally dried at 100° C. (212° F.) until of constant weight. The weight of dry argentic cyanide, when divided by 5, will represent the amount of hydrocyanic acid in 1 gram of the oil, and has, therefore, only to be subsequently multiplied by 100 in order to express the percentage. OLEUM SINAPIS 2BTHEREUM. OLEUM SINAPIS VOLATILE. Ger. iEtherisclies Senfol; Fr. Huile de moutarde ; Sp. Aceite esencial de mostaza. Volatile Oil of Mustard. A colorless or pale-yellow liquid, of a most penetrating, pun- gent odor, and having the specific gravity, 1.017 to 1.021 at 15° C. (59° F.); it boils at 148° C. (298.4° F.). When dropped into water, it sinks slowly, and dissolves in from 100 to 250 parts of it, the solubility of the oil in water apparently increasing with age ; if to the aqueous solution a few drops of solution of argentic nitrate be added, and heated, a black precipitate of argentic sul- phide will be produced. C4H5NS = (CS=N-C3Ha); 99 444 MANUAL OF CHEMICAL ANALYSTS. Mustard oil is miscible with alcohol, ether, chloroform, carbon bisulphide, and benzol, and with fatty and essential oils; it suffers decomposition with concentrated nitric acid, with the evolution of nitrous vapors, and the formation of a resinous residue. When dropped into concentrated sulphuric acid, mustard oil dissolves, without color, and without the evolution of heat, and when mixed with concentrated sulphuric acid, in the proportion of one part of oil to three parts of acid, being careful that the mixture is kept cool, sulphurous acid is evolved, and, after twelve hours, a colorless or but slightly brown, thick liquid or crystalline mass is formed, devoid of the odor of mustard oil. If 2 parts of mustard oil, 1 part of alcohol, spec. grav. 0.830, and 7 parts of ammonia-water, spec. grav. 0.960, be digested for several hours at a temperature of about 40° 0. (104° F.), and subsequently concentrated on the water-bath, it is converted into thiosinammine, C4II8lSr2S : C3H5-CNS + nh3 = C4H„NaS. The latter forms colorless and odorless, shining crystals, which possess a bitter taste, dissolve readily in water, alcohol, and ether, and fuse at 74° G. (165.2° F.). Examination: Admixtures of essential and fatty oils, carbon bisulphide, nitro- henzol, and alcohol, are indicated by becoming warm and dark- colored when about five or six drops of the oil are added to about 50 or 60 drops of concentrated sulphuric acid, in a dry test-tube; this is particularly the case when a mixture of 3 parts of con- centrated sulphuric acid and one part of nitric acid is employed, being careful in the operation of mixing the acids to avoid eleva- tion of temperature. If an admixture of carbon bisulphide, chloroform, etc., is sus- pected, advantage may be taken of their relatively low boiling- points, and their separation from the mustard oil effected by distillation from the water-bath ; to the distillate the respective special tests of identity, as described on pages 302 and 309, may then be applied. Admixtures of alcohol, benzol, and other hydrocarbons, are also indicated when two or three drops of the oil are allowed to fall into a test-tube, about one-third filled with cold distilled water; the oil should sink slowly to the bottom, remaining clear and transparent, until, after gently inclining the tube two or three times, it becomes opalescent. When contaminated with only a few per cent, of the above adulterations, the drops lose their transparency, and become opalescent, as soon as they fall into the water. Phenol (carbolic acid), gaultheria oil, and other similar bodies may readily be detected in the dilute alcoholic solution of the oil PHOSPHORUS. by the production of a violet color on the addition of a drop of solution of ferric chloride, whereas pure mustard oil remains unchanged. PHOSPHORUS. Ger. Phosphor ; Fr. Pliosphore; Sp. Fosforo. Phosphorus. P; 31. A translucent, slightly yellowish or nearly colorless solid, of a waxy lustre, and occurring usually in the form of cylindrical sticks. At ordinary temperatures it has about the consistence of wax, and may be easily cut with a knife, but at low temperatures is hard and brittle. It has a distinctive and disagreeable odor and taste, and the specific gravity 1.826 at 10° C. (50° F.); it melts at 44° C. (111.2° F.), forming a colorless or slightly yellow, strongly refractive liquid, which has the specific gravity 1.764; it boils in an atmosphere free from oxygen at 290° C. (554° F.), yielding a colorless vapor, but is slowly volatilized even at ordi- nary temperatures. Phosphorus is nearly insoluble in water, but dissolves in 350 parts of absolute alcohol at 15° C. (59° F.), in 240 parts of boiling- absolute alcohol, in 80 parts of ether, in about 50 parts of fatty oil, and very abundantly in carbon bisulphide; the latter dis- solving twenty times its weight of the substance, forming a color- less solution, which, however, requires to be handled with the utmost caution, as a single drop of it, when allowed to fall upon paper, soon bursts into flame. When exposed to the air, phosphorus emits white fumes, which are luminous in the dark, and have an odor somewhat resembling that of garlic; it is very inflammable, and must, therefore, be preserved under water in a cool place. It possesses strongly re- ducing properties, separating many metals, copper, lead, silver, etc., from solutions of their salts; by the action of direct sunlight, or by heating to 250° C. (482° F.), it is principally converted into the red or amorphous modification, which, among other characters, is distinguished from ordinary phosphorus by its insolubility in carbon bisulphide and other solvents, its unalterability by expo- sure to the air at ordinary temperatures, and its non-luminous and non-poisonous properties. By treatment with nitric acid, phosphorus is converted into tri-basic or orthophosphoric acid. Examination: Arsenic and Sulphur.—Commercial phosphorus from its method of manufacture frequently contains small amounts of arsenic and 446 MANUAL OF CHEMICAL ANALYSIS. sulphur, which, however, should not be present to any consider- able extent. They may be recognized, and, if required, the amount quantitatively determined, by the following method. 1 part of phosphorus is digested with a mixture of from 6 to 8 parts of nitric acid and 6 parts of distilled water until it is completely dissolved. The solution is then evaporated until nitrous vapors cease to be evolved, subsequently diluted with water so as to weigh about 12 parts, and, being heated to about 70° 0. (158° F.), hydrogen sulphide passed through the liquid for about half an hour, and finally, after the removal of the heat, until the liquid cools. The liquid is then set aside in a tightly corked flask for twenty-four hours, when any arsenic present, which should not be more than a trifling quantity, will become precipitated as yel- low arsenic trisulphide. If the amount of the latter is to be quantitatively determined, it may be collected on a tared filter, washed first with water, and, after drying, with pure carbon bisul- phide, in order to remove adhering sulphur, then dried at 100° C. (212° F.), and finally weighed: 100 parts of arsenic trisulphide, As2S3, correspond to 61 parts of metallic arsenic. Or the arsenic trisulphide may be converted into arsenic acid, by treatment with hydrochloric acid’and a little potassium chlorate on the water- bath, and, by the addition of test magnesium mixture, precipitated as ammonio-magnesium arseniate; the latter, when collected on a tared filter, washed with dilute ammonia-water, and dried at 105° C.(221° F.), corresponds to the formula MgNII4As04-f-JH90, and of which 100 parts correspond to 39.47 parts of metallic arsenic. The filtrate from the original precipitate of arsenic trisulphide when tested with solution of barium chloride should not afford more than a slight opalescence ; a white precipitate, insoluble in hydrochloric acid, will reveal the presence of sulphur, which, by the above treatment with nitric acid, becomes converted into sulphuric acid. Separation and Detection of Phosphorus in Forensic Investiga- tions,—In consideration of the extensive application of phosphorus in the preparation of lucifer matches, and of its employment in the form of a paste for the destruction of vermin, it is occasionally the object of search in cases of accidental or criminal poisoning, and a convenient and reliable method for its isolation and detection will therefore be briefly described. The substance under examination, which may consist of some article of food, the contents of a stomach, vomited matters, etc., is first examined by its odor, which will frequently reveal the presence of phosphorus, when existing in the free state. As a preliminary test, the substance is then brought into a glass flask, provided with a tightly fitting cork, and a small strip of paper moistened with a solution of argentic nitrate suspended from the cork, so as to project slightly into the interior of the flask. Suf- PHOSPHORUS. 447 ficient water is then added to the mixture to form a thin liquid, and also a little tartaric acid, in order to insure a distinctly acid reaction, after which the contents of the flask are very gently heated. If phosphorus be present, the paper moistened with the .silver solution will become blackened, either immediately or after standing for a few hours, in consequence of the slight volatiliza- tion of the phosphorus and the formation of argentic phosphide. As, however, the material under examination might also contain putrefying matters, accompanied by the development of hydrogen sulphide, etc., which would likewise cause a blackening of the silver paper, the precaution should be observed to insert in the cork of the flask, together with the silver paper, a small strip of paper moistened with a solution of plumbic acetate. If the latter remains unaffected, whilst the silver paper becomes blackened, the presence of phosphorus is rendered highly probable. In addition to the above-described preliminary test, the lumi- nosity of phosphorus in the dark affords the most striking and conclusive proof of its presence in the unoxidized state, and the substance should, therefore, invariably be further examined by the following method, which depends upon the volatilization of phosphorus with aqueous vapor, and the luminosity of the vapor when observed in the dark. The material under examination, acidulated with tartaric acid, and contained in the flask A (Fig. Ill), is gradually heated to the boiling-point of the liquid, and the vapors conducted by means of the bent glass tube, b, /?, into the tube, d, d, of a glass condenser, B, which is maintained in a vertical position by the stative, D. The condenser is kept cool by a current of water flowing from a through the rubber tubing into the funnel-tube, c, and passing out through the rubber tubing, e, whilst the flask, G., serves for the reception of the distillate. In the presence of ordinary phosphorus, and by conducting the distillation in a dark room, a luminous ring, which remains visible for a considerable time, will be observable in the cooled portions of the tube, d, d, while if considerable phosphorus be present, small particles of the latter will also frequently be found in the distillate. It should, however, be considered that the presence of alcohol and ether, as also of volatile oils, retard or prevent the luminosity of the vapor, but, as soon as these are volatilized, the characteristic reaction may at once be observed. If a quantita- tive determination of the phosphorus be required, the distillate, together with any particles of suspended phosphorus which it may contain, is mixed with a sufficient amount of good chlorine-water, and, after being allowed to stand for about twelve hours, evapo- rated to a small volume upon the water-bath. The phosphorous acid of the distillate is thereby converted into phosphoric acid, and, after supersaturation with ammonia-water, may be precipi- tated by test magnesium mixture as ammonio-magnesium phos- MANUAL OF CHEMICAL ANALYSIS. pliate; the latter is then collected upon a filter, washed with a little dilute ammonia-water, dried, and by ignition in a small porcelain crucible, converted into magnesium pyrophosphate, Fig. 141. Mg2P207, and its weight finally determined: 100 parts of the latter compound correspond to 27.92 parts of phosphorus. If in the above-described method for the detection of phos- phorus it should also be necessary or desirable to take into con- sideration the possible presence of hydrocyanic acid, the same method of investigation may be pursued, reserving, however, the first portion of the distillate for examination for hydrocyanic acid, as described on page 162, or for other readily volatile sub- stances by which it may be accompanied. The subsequent por- tion of the distillate may then be employed for the qualitative or quantitative determination of phosphorus, in the manner above described. PICROTOXINUM. PHYSOSTIGMINA3 salicylas. PHYSOSTIGMINUM SALICYLICUM. Ger. Salioylsaures Pliysostigmin ; Fr. Salicylate de physostigmine ; Sp. Salicilato de fisostigmina. Salicylate of Physostigmine. Physostigmine Salicylate. C15H21N302.C7Hfl03; 413. Colorless or faintly yellowish, shining, acicular, or short colum- nar crystals, which by long exposure to air and light gradually assume a reddish color; when strongly heated on platinum-foil they are completely dissipated. Physostigmine salicylate is soluble in 130 parts of water and in 12 parts of alcohol at 15° C. (59° P.); in 30 parts of boiling water, and very freely in boiling alcohol. The aqueous solution is neutral in its action upon litmus, and possesses a bitter taste; it is precipitated by the ordinary alkaloidal reagents, is rendered turbid by iodine-water, and yields with a drop of a dilute solution of ferric chloride a violet coloration; upon exposure to diffused light for one or two days it assumes a reddish color. The solu- tion of the salt in concentrated sulphuric acid is at first colorless, but afterwards assumes a yellow color. If sodium bicarbonate be added to the aqueous solution of the salt, which is afterward shaken with ether, and the ethereal solution separated and allowed to evaporate spontaneously, an amorphous residue of physostig- mine is obtained ; the latter possesses a decidedly alkaline reaction, fuses at 4:5° C. (113° F.), and its aqueous solution, on exposure to the air, soon becomes red, or sometimes intensely blue, resulting from its partial decomposition; if sulphurous acid be added to such a solution, the color is discharged, but returns again on the evaporation of the acid. On concentrating the aqueous solution, which has been precipitated by sodium bicarbonate and shaken with ether, to a small volume, and supersaturating with sulphuric acid, a bulky white precipitate is obtained, which responds to the reactions of salicylic acid, page 181. A solution of physostigmine, or any of its salts, when applied to the eye, strongly contracts the pupil. PICROTOXINUM. Picrotoxin. Ger. Pikrotoxin ; Fr. Picrotoxine ; Sp. Picrotoxina. C9H]0O4; 182. Colorless, shining, prismatic crystals, which undergo no change by exposure to the air; they are odorless, possess an intensely 450 MANUAL OF CHEMICAL ANALYSIS. bitter taste, and are neutral in their action upon litmus. On being heated to about 200° C. (392° F.) the crystals melt to a yel- low liquid; when heated on platinum-foil they char, and at a strong heat are finally completely dissipated. Picrotoxin is soluble in 150 parts of water and 10 parts of alco- hol at 15° C. (59° F.), in 25 parts of boiling water and 3 parts of boiling alcohol; the latter solution forming upon cooling a mass of silky prisms. It is also soluble in about 2.5 parts of ether, and readily in amylic alcohol and chloroform ; concentrated acetic acid likewise dissolves it, as do also the fixed alkalies and ammo- nia-water, and from the latter solutions it is precipitated unchanged on the addition of an acid. If a little picrotoxin be placed in a capsule and mixed with four or five drops of concentrated sulphuric acid, the crystals dissolve with a golden-yellow color, wrhich changes to saffron-yellow; on subsequently adding a trace of powdered potassium bichromate, a violet-green color is produced, and, upon dilution with water, a clear yellowish-green solution is formed. When a little picrotoxin is intimately mixed with 3 or 4 times its weight of potassium nitrate, and the mixture moistened with sulphuric acid, no change is observed, but on subsequently adding sufficient of a solution of potassium or sodium hydrate to impart a strongly alkaline reaction, it assumes an evanescent brick-red color. The aqueous solution of picrotoxin, to which a few drops of a dilute solution of potassium or sodium hydrate have been added, reduces an alkaline solution of cupric tartrate on warming; in this respect resembling a solution of grape-sugar and many other indifferent organic substances, although its reducing properties are inferior in extent. It also resembles a solution of grape- sugar in that its alkaline solution becomes decomposed on warm- ing; the solution becoming at first yellow, and then brick-red. Picrotoxin being a perfectly neutral principle, and devoid of nitrogen, its solution is not affected by solutions of the salts of platinum, gold, and mercury, or by potassio-mercuric iodide, tan- nic acid, or other alkaloidal reagents, which thus distinguishes it from and indicates the absence of alkaloids. It is absorbed by ether from its acidulated aqueous solution, and may thus be sepa- rated from alkaloids and other complex organic principles with which it may be associated, as described on page 106. PIPERINA. 451 PILOCARPINiE HYDROCHLORAS. PILOCARPINUM IIYDROCHLORICUM SEU MURIATICUM. Hydrochlorate of Pilocarpine. Pilocarpine Hydro chlorate. Ger. Salzsaures Pilocarpin ; Fr. Chlorliydrate de pilocarpine ; Sp. Hidroclorato de pilocarpina. CnHlfiN202.HCl; 244.4. Small, colorless, deliquescent crystals, without odor, but pos- sessing a slightly bitter taste. When heated on platinum-foil they first melt, and at a strong heat are finally completely dissi- pated. Pilocarpine hydrochlorate is readily soluble in water and in alcohol, but almost insoluble in ether, chloroform, benzol, and carbon bisulphide. The aqueous solution is neutral in its action upon litmus, and possesses a slightly bitter taste; when slightly acidulated it is not precipitated by ammonia-water, and solution of sodium hydrate produces only in a concentrated solution of the salt a slight turbidity; with solution of argentic nitrate the aqueous solution yields a white precipitate, which is insolu- ble in nitric acid, but soluble in ammonia water. With concen- trated sulphuric acid the crystals of the salt yield a yellow, with nitric acid, spec. grav. 1.4, a faintly greenish-violet, and with sul- phuric acid and potassium bichromate an emerald-green color. An aqueous solution of pilocarpine, or any of its salts, when applied to the eye, strongly contracts the pupil. PIPERINA. Piperine. Ger. Piperin ; Fr. Piperine ; Sp. Piperina. C17H19N03; 285. Colorless, or slightly yellowish, shining, four-sided prisms, be- longing to the rhombic system, and permanent in the air; they are neutral in their action upon litmus, odorless, and almost taste- less when first placed on the tongue, but by prolonged contact produce a sharp, biting sensation. When heated to about 128° C. (262° F.), they melt to a clear, yellowish liquid, which, on cool- ing, congeals to a resinous mass; at a higher temperature they are decomposed, and, when strongly heated on platinum-foil, they take fire, and are finally completely dissipated. Piperine is almost insoluble in either cold or hot water ; it is soluble in 30 parts of alcohol at 15° C. (59° F.\ in 1 part of boil- ing alcohol, and slightly soluble in ether, chloroform, benzol, and the volatile oils. 452 MANUAL OF CHEMICAL ANALYSIS. Concentrated sulphuric acid dissolves piperine with a dark blood-red color, which disappears on dilution with water. When treated with cold concentrated nitric acid it assumes a greenish- yellow color, which rapidly changes to orange and red, and gradu- ally dissolves with a reddisli color; on adding to this solution an excess of solution of potassium hydrate, the color is at first pale yellow, but, on boiling, it deepens to blood-red, while at the same time vapors of an alkaline reaction and of a peculiar odor (pipe- ridine) are given off. On heating with soda-lime, or by prolonged boiling with an alcoholic solution of potassium hydrate, piperin is converted, by the absorption of a molecule of water, into piperi- dine, C4H,,N, and crystallizable piperic acid, C]2H10O4: Piperidine is a clear colorless alkaloid, having the odor of pep- per and ammonia, and possessing strongly basic properties ; it boils at 106° C. (222.8° F.), is soluble in all proportions in water and alcohol, and combines with acids to form well crystallizable salts. C17H10NO3 + H20 = CSHUN + C12H10O4. Piperine is a very feeble base, being almost insoluble in the dilute mineral acids, and not combining with them, but forms well crystallizable double salts with the chlorides of platinum, mercury, and cadmium. PLUMBI ACETAS. PLUMBUM ACETICUM. Acetate of Lead. Sugar of Lead. Plumbic Acetate. Ger. Essigsaures Bleioxyd, Bleizucker ; Fr. Acetate de plomb ; Sp. Acetato de plomo. Pb(C2H302)2+8H20; 378.5. Colorless, transparent, brilliant, monoclinic prisms or plates (Fig. 142), or, as generally met with, heavy, compact crystalline masses, somewhat resembling loaf-sugar, having an acetous odor and a sweet, as- tringent, afterwards metallic taste; they contain three molecules (14.21 per cent.) of water of crystallization, and effloresce slowly and absorb carbonic acid when exposed to the air; they become black when in contact with gaseous or dissolved hydrogen sulphide. When heated to 40° C. .(104° F.) plumbic acetate loses its water of crystallization quickly and completely ; it melts at 75° C. (167° F.) in its water of crystallization, with the loss of water and acetic acid, and is further decomposed at a higher temperature, Fig. 142. PLUMBUM. 453 leaving a black residue, which is reduced, at a red heat, to plum- bic oxide or to metallic lead. Plumbic acetate is soluble in 1.8 parts of water and 8 parts of alcohol at 15° 0. (59° F.), in 0.5 part of boiling water and 1 part of boiling alcohol, but insoluble in ether and in chloroform; its solution in water has generally a slightly turbid appearance from traces of plumbic carbonate, which, however, disappears upon the addition of acetic acid; the aqueous solution has a feeble acid reaction, forms white precipitates with the alkaline hydrates (soluble in excess of potassium and sodium hydrates), with the alkaline carbonates, and with sulphates and chlorides, a yellow one with iodides, and a black one with hydrogen sulphide and with sulphides. When completely precipitated by sodium chlo- ride, the colorless filtrate will assume a deep-red tint with a few drops of solution of ferric chloride. Examination: Salts of the Alkalies, Alkaline-Earths, and Zinc.—An aqueous solution of the salt is acidulated with hydrochloric acid, filtered, and the lead completely precipitated by saturation with hydrogen sulphide. The filtrate, on evaporation, should leave no residue. If a residue is obtained, it may be dissolved in water, and a por- tion of the solution tested with sodium carbonate, when a white precipitate will indicate the presence of salts of barium, calcium, magnesium, or zinc, which may be distinguished by the appro- priate tests; if the dissolved residue gives no precipitate with sodium carbonate, potassium or sodium salts will be indicated. Copper may be detected by precipitating a solution of the salt with dilute sulphuric acid, and testing the filtrate with potassium ferrocyanide, or, by subsequent supersaturation with ammonia- water, a reddish-brown precipitate in the first instance, and a blue coloration of the liquid in the latter, will reveal the presence of copper. PLUMBI CARBONAS. PLUMBI SUBC/iRBONAS. PLUMBUM CARBONICUM. CERUSSA. Carbonate or Subcarbonate of Lead. White Lead. Basic Plumbic Carbonate. Ger. Basisch kohlensaures Bleioxyd, Bleiweiss ; Fr. Carbonate de plomb ; Sp. Carbonato de plomo. (Pb003)2 + Pb(OII)2; 773.5. A heavy, white, opaque, and perfectly amorphous powder, or friable lumps, which are blackened by hydrogen sulphide. Heated upon charcoal before the blow-pipe, plumbic carbonate becomes yellow, fuses, and is finally reduced to soft, malleable metallic glo- bules. It is insoluble in pure water, but somewhat soluble in MANUAL OF CHEMICAL ANALYSIS. water containing much carbonic acid or alkaline bicarbonates; it is wholly dissolved, with effervescence, by diluted acetic and nitric acids, affording colorless solutions, of a sweet, astringent taste ; these solutions yield white precipitates with dilute sul- phuric and hydrochloric acids, and with soluble sulphates and chlorides; they also give a white precipitate with solutions of potassium or sodium hydrate, soluble in an excess of the precipi- tant, a yellow one with potassium iodide, and a black one with hydrogen sulphide. * Examination: Admixtures of barium, calcium, and plumbic, sulphates, remain behind, upon solution of the white lead in dilute nitric acid. Their quantity may be ascertained by dissolving 100 parts of the sample in a sufficient quantity of warm diluted nitric acid, and collecting and washing the insoluble residue upon a tared filter; when completely dry, the weight indicates the percentage of such admixtures. If the nature of the admixture has to be ascertained, the residue is intimately mixed with about three times its weight of anhy- drous sodium carbonate, and strongly heated in a porcelain cru- cible. After being allowed to cool, the fused mass is lixiviated with water, filtered, and the filtrate supersaturated with nitric acid and tested with barium chloride, when a white precipitate will reveal the presence of sulphate. The residue, upon the filter, may then be dissolved in acetic acid, and tested with hydrogen sulphide for lead, when, after filtration, if necessary, the filtrate may be tested with potassium chromate for barium, and with ammonium oxalate for calcium. Admixtures of calcium carbonate or phosphate, barium carbo- nate, and oxide of zinc, are also soluble in nitric acid. In order to detect and to distinguish them, the nitric-acid solution of the sample is freely diluted with water, and is subsequently saturated and completely precipitated with hydrogen sulphide; it is then filtered, and warmed, to expel the excess of gas, and a small por- tion of the solution is supersaturated with sodium carbonate; an ensuing white precipitate will confirm the presence of the above admixtures; in order to ascertain their nature, the remainder of the solution is nearly neutralized with a few drops of solution of potassium hydrate and then tested, in separate portions, with solu- tion of calcium sulphate for barium, with oxalic acid, after the previous addition of a little sodium acetate, for calcium, and by the addition first of sodium acetate and subsequently of ammo- nium sulphide for zinc. PLUMBUM. 455 PLUMBI IODIDUM. PLUMBUM IODATUM. Ger. Jodblei; Fr. Iodure de plomb ; Sp. Ioduro de plomo. Iodide of Lead. Plumbic Iodide. Pbl2; 459.7. A bright-yellow, heavy, inodorous powder, when obtained by precipitation; or shining, golden-yellow, six-sided laminm or prisms of the hexagonal system, when allowed to slowly crystallize from its solutions. Its specific gravity is 6.1. When heated in a dry test-tube, plumbic iodide becomes red, and fuses to a thick reddish- brown liquid, which congeals, on cooling, to a yellow crystalline mass; at a stronger heat, it is decomposed, with the evolution of violet vapors; and, when heated with exsiccated sodium carbo- nate, on charcoal, before the blow-pipe, it is entirely reduced to metallic globules. Plumbic iodide is soluble in 2270 parts of water at 14° C. (57.2° F.), in 294 parts of boiling water, and also, to a slight extent, in alcohol; a hot saturated aqueous solution, on cooling, deposits the salt in brilliant yellow scales; it is readily soluble in acetic acid, in solution of potassium or sodium hydrate, in concen- trated solutions of the alkaline or earthy iodides, in a warm solu- tion of ammonium chloride, and in solution of sodium hyposul- phite (thiosulphate), from all of which solutions hydrogen sulphide precipitates black plumbic sulphide. When shaken with chlorine-water, plumbic iodide suffers par- tial decomposition, and yields a filtrate from which chloroform or carbon bisulphide will extract iodine, with a red color. When boiled with solutions of alkaline carbonates, it is decomposed, with the formation of an alkaline iodide and plumbic carbonate. When boiled with granular or powdered zinc and water, less readily with iron, plumbic iodide is likewise decomposed, form- ing soluble zinc or ferrous iodide and metallic lead. Examination: Plumbic chromate, which, in its physical characters, bears some resemblance to plumbic iodide, may readily be distinguished from the latter by triturating 1 part of the salt with 2 parts of ammo- nium chloride, in a porcelain mortar, and subsequently adding 2 parts of water, when a complete and colorless solution should be formed. If the solution be afterwards diluted with water, and the lead completely precipitated by hydrogen sulphide, the fil- trate, on evaporation to dryness and subsequent ignition, should leave no residue, thus confirming the absence of other fixed impu- rities. 456 MANUAL OF CHEMICAL ANALYSIS. PLUMBI NITRAS. PLUMBUM NITRICUM. Ger. Salpetersaures Bleioxyd ; Fr. Azotate de plomb ; Sp. Nitrato de plomo. Nitrate of Lead. Plumbic Nitrate. Pb(JST03)2; 330.5. Colorless, transparent or opaque, anhydrous, octahedral crys- tals, permanent in the air. Heated in a dry test-tube, the crys- tals decrepitate, emit yellow nitrous vapors, and leave a residue of plumbic monoxide. When thrown on red-hot charcoal, the salt detonates with brilliant sparks, and deflagrates when triturated with sulphur. Plumbic nitrate is soluble in 2 parts of water at 15° C. (59° F.), and in 0.8 part of boiling water; it is almost insoluble in alcohol. Its aqueous solution has a sweet, astringent, afterwards metallic taste, and an acid reaction; it gives a white precipitate with sul- phuric or hydrochloric acid, and with solutions of sulphates or chlorides, a yellow one with potassium iodide, and a black one with hydrogen sulphide. When triturated with concentrated sul- phuric acid, and heated, the salt evolves red nitrous fumes. Examination: Salts of the Alkalies and Alkaline Earths.—An aqueous solution of the salt is acidulated with hydrochloric acid, filtered, and the lead completely precipitated by saturation with hydrogen sulphide. The filtrate, on evaporation, should leave no residue. If a residue is obtained, it may be dissolved in water, and a portion of the solution tested with sodium carbonate ; an ensuing white precipi- tate would indicate the presence of barium, which may be con- firmed by other tests. If the dissolved residue gives no precipi- tate with sodium carbonate, the presence of potassium or sodium salts will be indicated. Copper may be detected, in the aqueous solution of the salt, by completely precipitating it with dilute sulphuric acid, and testing the filtrate with potassium ferrocyanide, or, by subsequent super- saturation with ammonia-water; a reddish-brown precipitate in the first instance, and a blue coloration of the liquid in the latter, will reveal the presence of copper. 457 PLUMBUM. PLUMBI OXIDUM. PLUMBUM OXYDATUM FUSCUM. LITHARGYRUM. Oxide of Lead. Litharge. Plumbic Monoxide. Ger. Bleioxyd, Bleiglatte ; Fr. Litharge; Sp. Litargirio. PbO; 222.5. A heavy, yellowish or reddish-yellow powder, or small, shining, rhombic scales of the same color, devoid of odor and taste. Its specific gravity is 9.36. It fuses at a red heat, assuming thereby a brownish-red tint, and solidifies on cooling to a crystalline mass; when heated on charcoal, before the blow-pipe, it is reduced to the metallic state. Plumbic monoxide is but sparingly soluble in water, imparting thereto a feeble alkaline reaction; it is soluble in warm solutions of the fixed alkaline hydrates, and in diluted nitric and acetic acids, without effervescence or residue ; it slowly absorbs carbonic acid from the atmosphere, and contains the more carbonate the longer it has been exposed to the air; from this cause, when very old, it becomes more or less effervescent with acids. The nitric- acid solution of plumbic monoxide yields white precipitates with dilute sulphuric and hydrochloric acids, with solutions of sul- phates and chlorides, and with the alkaline hydrates, which latter, ammonia-water excepted, re-dissolve the precipitate, when added in excess; it gives a black precipitate with hydrogen sulphide, and, when neutral, a yellow one with potassium iodide. Examination: Plumbic carbonate and red oxide are detected, when a small quantity of the litharge is triturated with a little water, and the mixture is added, drop by drop, to concentrated nitric acid, in a test-tube; carbonate is recognized by effervescence; red oxide by a brown residue, insoluble in an excess of acid, with gentle warm- ing, but soluble upon the addition of a little oxalic acid or sugar; if this residue, however, does not dissolve, an adulteration with powdered silicates, crude ferric oxide, etc., is indicated. Silicates are also indicated by a white turbidity or a flocculent precipitate, occurring in the solution after the addition of the oxalic acid, in the preceding test. Zinc oxide and alkaline earths may be detected by saturating the dilute nitric acid solution with hydrogen sulphide, so as to completely precipitate the lead, and filtering; the filtrate, on evaporation, should leave no residue. If a residue is obtained, it may be dissolved in a little water, and a portion of the solution tested with sodium carbonate ; an ensuing white precipitate would indicate zinc, barium, or calcium oxides. In order to distinguish these, the remainder of the solution is tested, in separate portions, with ammonium sulphide for zinc, with solution of calcium sul- 458 MANUAL OF CHEMICAL ANALYSIS. phate for barium, and with ammonium oxalate for calcium; an ensuing white precipitate in either instance will indicate the re- spective impurities. Copper may be detected by a blue coloration of the liquid, when the dilute nitric acid solution of the oxide is precipitated by sulphuric acid, and subsequently supersaturated with ammonia- water. Metallic lead may be detected by its remaining undissolved when the oxide is boiled for a short time with acetic acid, or when digested with a warm solution of plumbic acetate or potas- sium hydrate. It may likewise be detected by digesting a small portion of the litharge with a solution of plumbic nitrate, at a gentle heat, and with occasional agitation, for about half an hour ; a few drops of the decanted liquid are then diluted with a little water, a little mucilage of starch, and a few drops of dilute sulphuric acid and solution of potassium iodide added. If the sample contains even traces of metallic lead, this gives rise to the formation of plumbic nitrite, which will decompose the potassium iodide, with the liberation of iodine, and at once produce a blue color with the starch. PLUMBI OXIDUM RUBRUM. Bed Oxide of Lead. Minium. Triplumbic Tetroxide. Plumbic Plumbate. Ger. Rotlies Bleioxyd, Mennige; Fr. Oxyde rouge de plomb ; Sp. Oxido rojo de plomo. PLUMBUM OXYDATUM RUBRUM. MINIUM. Pb304; 683.5. A heavy, orange-red, crystalline powder, which becomes dark when heated, but regains its original color on cooling; at a red heat it loses oxygen and is converted into the monoxide. Heated upon charcoal, before the blow-pipe, it fuses, and is reduced to metallic globules. Its specific gravity varies from 8.6 to 9.1. Red oxide of lead is almost completely soluble in twenty times its weight of warm glacial acetic acid, forming a colorless solu- tion, which is not precipitated by the addition of a mixture of ether and alcohol; when treated with warm dilute nitric or acetic acid it only partially dissolves, leaving a brown residue of per- oxide, which is soluble, however, upon the addition of a little oxalic acid or sugar. A slight remaining turbidity, of a whitish appearance, is due to silicic acid, with which red oxide of lead is generally more or less contaminated ; any insoluble red or brown residue, however, would indicate impurities. POTASSIUM. 459 The impurities and admixtures which red oxide of lead is liable to contain, and the methods of detecting them, are the same as mentioned and described under litharge, on pages 457-458. POTASSA SULPHURATA. POTASSII SULPHURETUM. POTASSII SULPHIDUM. POTASSIUM SEU KALIUM SUEFURATUM. HEPAR SULFURIS. Sulphurated Potassa. Sulphuret of Potassium. Potassium Sulphide. Ger. Schwefelleber ; Fr. Sulfure de potasse ; Sp. Sulfuro de potasio. Solid, fused fragments, of a yellowish-brown color, when freshly prepared or recently broken ; on exposure to the air they assume a greenish appearance, and finally become of a dirty white, in consequence of gradual decomposition by the action of atmos- pheric moisture and oxygen, the sulphides being successively converted, with the evolution of hydrogen sulphide, into hypo- sulphite (thiosulphate), sulphite, and ultimately sulphate. When moistened with acids, sulphurated potassa evolves hydrogen sul- phide. Sulphurated potassa, which is usually a variable mixture of higher potassium sulphides with hyposulphite (thiosulphate), sul- phite, and sulphate, and with undecomposed carbonate, is soluble in about 2 parts of water at 15° C. (59° F.), and is also soluble in alcohol, leaving behind in the latter case the oxygen salts; these solutions have an orange-yellow color, a nauseous, alkaline, bitter taste, and the odor of hydrogen sulphide, which is abundantly evolved, with the separation of sulphur, upon the addition of acids; they precipitate metallic sulphides from the solutions of most of the metallic salts. If a solution of 1 part of the salt in 20 parts of water be boiled with an excess of acetic acid until hydrogen sulphide ceases to be evolved, the solution filtered, and to the cold filtrate an excess of tartaric acid added, a white, crys- talline precipitate will be produced. The value of sulphurated potassa, when free from an undue proportion of carbonate, may be approximately estimated by the amount of crystallized cupric sulphate which is required to decompose it: CuS04.5H20 + K2S3 = CuS + S2 + K2S04 + 5H20. In consideration of the amount of admissible foreign salts, the preparation should respond to the following test: 10 grams of the sulphurated potassa are triturated with 12.69 grams of crystallized cupric sulphate and 60 grams of water, and subsequently filtered; 460 MANUAL OF CHEMICAL ANALYSIS. the filtrate should be colorless, and afford no coloration or tur- bidity upon saturation with hydrogen sulphide (indicating the presence of at least 56 per cent, of true potassium sulphide). POTASSII ACETAS. POTASSIUM SEU KALIUM ACETIOUM. Acetate of Potassium. Potassium Acetate. Ger. Essigsaures Kalium ; Fr. Acetate de potasse ; Sp. Acelato de potasa. A snow-white, very deliquescent salt, of a foliaceous or fibrous satiny appearance, or a white granular powder, unctuous to the touch, and of a warm, pungent, saline taste, and possessing a neu- tral or faintly alkaline reaction; it fuses at 292° C. (557.6° F.) without change, solidifying upon cooling to a crystalline mass, but is decomposed at a higher temperature with the evolution of empyreumatic, inflammable vapors, leaving behind a mixture of carbon and potassium carbonate. Potassium acetate is soluble in 0.4 part of water, in 2.5 parts of alcohol, and in 3 parts of glycerin at 15° C. (59° F.); its dilute aqueous solution assumes a deep red color with one or two drops of solution of ferric chloride, and yields a white granular precipi- tate with a concentrated solution of sodium bitartrate or of tar- taric acid. Potassium acetate disengages the vapor of acetic acid with concentrated sulphuric acid, and the vapor of acetic ether when heated with a mixture consisting of equal parts of alcohol and sulphuric acid. Examination: Metals are detected in the aqueous solution, previously acidu- lated with hydrochloric acid, bv a dark coloration or precipitate with hydrogen sulphide, or, after neutralization with ammonia- water, by the addition of ammonium sulphide; if a precipitate is produced by these reagents, a portion of the acidulated solution of the salt may then be tested with potassium ferrocyanide ; cop- per will be indicated by a reddish-brown coloration, iron by a blue one. Tartrates, sulphates, and chlorides are indicated by the occur- rence of a turbidity when a concentrated aqueous solution of the salt is dropped into strong or absolute alcohol; the latter two are also recognized in the diluted solution, acidulated with nitric acid, by white precipitates when tested in separate portions with argentic nitrate and barium nitrate respectively. Carbonates, silica, and alkaline earths may be detected by dis- solving a portion of the salt in water acidulated with hydrochloric KC2H302; 98. POTASSIUM. 461 acid; effervescence will indicate carbonates; upon evaporating the resulting solution to dryness, and treating the residue with water, the silica will remain undissolved ; and the solution, after filtration, and the addition of sodium carbonate in slight excess, will yield a white precipitate, if alkaline earths be present. Organic impurities will be indicated by a dark coloration when a little of the salt is strewn upon colorless concentrated sulphuric acid. Estimation: About 5 grams of the salt are accuratel}7- weighed, and ignited, at a strong heat, in a porcelain crucible, until inflammable vapors cease to be evolved; the residue is then dissolved in water, and the solution, contained in a beaker, after the addition of a few drops of a solution of litmus, is titrated with a standard solution of oxalic or sulphuric acid (page 82) until, with the application of a gentle heat to effect the complete removal of the disengaged carbonic acid gas, a slight excess of acid has been employed, and the liquid assumes a bright cherry-red color. The excess of acid is then inversely titrated with a standard solution of potassium or sodium hydrate (page 87) until a decided blue coloration of the liquid is just produced, when the number of cubic centimeters of alkali solution, subtracted from that of the acid first employed, will give the amount of the latter required for the exact neu- tralization of the salt. One cubic centimeter of the normal acid solution corresponding to 0.069 gram of potassium carbonate, or, as its equivalent, 0.098 gram of potassium acetate, the latter deci- mal, multiplied by the number of cubic centimeters of the normal acid solution employed for neutralization, will represent the amount of pure potassium acetate in the quantity under esti- mation. By the employment of 4.9 grams of potassium acetate, and a strictly normal solution of oxalic or sulphuric acid, the number of cubic centimeters of acid required for the exact neutralization of the salt, after the above treatment, when multiplied by 2, will represent without further calculation the percentage purity of the salt under examination. The United States Pharmacopoeia requires that if 4.9 grams of potassium acetate are ignited until gases cease to be evolved, the alkaline residue should require, for complete neutralization, not less than 49 cubic centimeters of the volumetric solution of oxalic acid (corresponding to at least 98 per cent, of absolute potassium acetate). 462 MANUAL OF CHEMICAL ANALYSIS. POTASSII BICARBONAS. POTASSIUM SEU KALIUM BICARBONICUM Bicarbonate of Potassium. Potassium Bicarbonate. Hydrogen Potassium Carbonate. * Ger. Zweifacli kolilensaures Kalium; Fr. Bicarbonate de potasse ; Sp. Bicarbonato de potasa. KI-IC03; 100. Transparent, colorless, prismatic crystals, belonging to the mono- clinic system, and having the specific gravity 2.153 ; they are per- manent in dry air, odorless, of a saline and slightly alkaline taste, and a feebly alkaline reaction; when exposed to a red heat, they lose, in consequence of the elimination of water and carbonic acid gas, 31 per cent, of their weight, and are converted into the normal or neutral carbonate : 2KHC03 = K2C03 + H20 -f C02. Potassium bicarbonate is soluble in 3.2 parts of water at 15° C. (59° F.), forming a slightly alkaline solution which effervesces with acids and evolves carbonic acid gas when heated to boiling; it gives a white granular precipitate with excess of tartaric acid, but no precipitate with magnesium sulphate unless when heated. It is almost insoluble in alcohol. Examination: Normal potassium or sodium carbonates will be indicated by a strongly alkaline reaction of the salt to test-paper, and may be detected in the cold aqueous solution by testing it, in separate portions, with a solution of magnesium sulphate and with mercuric chloride; a white precipitate with the first-named reagent, solu- ble upon the addition of ammonium chloride, and a brick-red one with the second, would indicate neutral carbonate. They may also be detected by carefully mixing, without agitation, equal volumes of a solution of 1 part of potassium bicarbonate in 200 parts of water with a solution of 1.22 parts of crystallized barium chloride in 200 parts of water; the immediate formation of a white pre- cipitate will likewise reveal the presence of neutral carbonate. Other Impurities.—The aqueous solution is slightly supersatu- rated with diluted nitric acid, evaporated to dryness, and the dried mass re-dissolved in water; a white insoluble residue would indi- cate silicates; the solution, if necessary, is filtered, and tested in separate portions with argentic nitrate for chloride, and with barium nitrate for sulphate; a white turbidity with argentic nitrate, gradually turning dark, would indicate potassium hypo- sulphite (thiosulphate); in this case, as a confirmatory test, a small portion of the potassium bicarbonate may be dissolved in about five times its weight of water, the solution slightly supersatu- rated with acetic acid, and then a few drops of mucilage of starch, and subsequently of solution of iodinized potassium iodide are added, drop by drop; the first drops of the latter reagent should POTASSIUM. 463 at once produce the blue coloration which will not take place immediately if potassium hyposulphite be present in the salt. Nitrates may be detected by dissolving a portion of the salt in cold concentrated sulphuric acid, and, after effervescence has ceased, carefully adding to the solution a concentrated solution of ferrous sulphate, so as to form two layers (Fig. 143); a dark Fig. 143. coloration at the surface of contact of the two liquids will reveal the presence of nitrates. Metals are detected by saturating a solution of the salt, pre- viously acidulated with hydrochloric acid, with hydrogen sul- phide, and, after the separation of any precipitate which may be thus formed, by the subsequent addition of ammonia-water and ammonium sulphide; a dark coloration or precipitate in either instance would indicate the presence of metallic impurities, which may be further examined as to their character by the methods of systematic analysis, as described on pages 51 to 61. Estimation: One hundred parts of potassium bicarbonate require for exact neutralization 70 parts of citric, or 75 parts of tartaric, acid. The quantitative estimation of the salt may, however, be more conveniently accomplished volumetrically, by dissolving 5 grams of the salt in a small quantity of water, and titrating the solution, contained in a beaker, after the addition of a few drops of litmus solution, with a standard solution of oxalic or sulphuric acid (page 82). The liquid, during the addition of the acid, should be gently warmed, in order to completely expel the disengaged carbonic acid gas, and a slight excess of acid employed, which will be evi- dent by the bright cherry-red tint of the liquid; the excess of 464 MANUAL OF CHEMICAL ANALYSIS. acid being subsequently inversely titrated by means of a standard alkali solution (page 87). The number of cubic centimeters of normal acid which are thus required for the exact neutralization of 5 grams of the salt, when multiplied by 2, will represent the percentage purity of the salt under examination : One cubic centi- meter of the normal acid corresponding to 0.1 gram of pure crys- tallized potassium bicarbonate. POTASSII BICHROMAS. POTASSIUM SEU KALIUM BICHROMICUM. KALIUM CHROMIC LrM RUBRUM. Bichromate of Potassium. Potassium Bichromate. Ger. Doppelt cliromsaures Kalinm ; Fr. Bichromate de potasse ; Sp. Bicromato de potasa. K2Cr207; 294.8. Large, transparent, orange-red, prismatic, or tabular crystals, belonging to the triclinic system (Fig. 144), and having the spe- cific gravity 2.692 at 4° C. (39.2° F.). They are anhydrous, and permanent in the air; ex- posed to heat, they fuse below redness, forming a dark-brown liquid, which solidifies on cooling to a crystalline mass, and are decomposed at a red heat with the evolution of oxygen, leaving a residue consisting of green chromic oxide and yellow potassium chromate, which may be separated by the ready solubility of the latter in water. Potassium bichromate is soluble in 10 parts of water at 15° C. (59° F.), and in 1.5 parts of boiling water, yielding an intensely orange- yellow solution, with a cooling, bitter, metallic taste, and an acid reaction ; it is insoluble in alcohol. The aque- ous solution becomes lemon-yellow with the alkaline hydrates and carbonates, and green or almost colorless, with the formation of a brown precipitate, when heated with reducing agents; it forms insoluble, colored bichromates and chromates with the solutions of most metallic salts. When the powdered salt is heated with hydrochloric acid, vapors of chlorine are evolved, and when heated with concentrated hydrochloric or sulphuric acid and a little alcohol, a vehement reduction takes place, and the liquid acquires a deep green color. A concentrated solution of the salt gives a white, granular precipitate with a concentrated solution of sodium bitartrate. Fig. 144. POTASSIUM. 465 Examination: Sulphate may be detected by heating to boiling a mixture of the aqueous solution with an equal volume of concentrated hydro- chloric acid and a few drops of alcohol; when subsequently diluted with water and tested with barium chloride, a white precipitate will ensue if sulphate be present. Chloride may be detected when the aqueous solution of the salt is mixed with about one-third of its volume of concentrated sul- phuric acid, and when afterward a little alcohol is added; the mixture will become green, with spontaneous ebullition; it is then heated, and subsequently diluted with water, and tested with argentic nitrate for chloride. POTASSII BITARTRAS. POTASSIUM SEU KALIUM BITARTARICUM. TARTARUS Bitartrate of Potassium. Cream of Tartar. Potassium Bitartrate. DEPURATES. CREMOR TARTAR!. Ger. Saures weinsaures Kalium, Weinstein ; Fr. Tartrate acide de potasse ; Sp. Bitartrato de potasa KHCHO _ CH(OII)-CO-OK Jvnonv^6— | .icq CH(OH)-CO-OH’ White, semi-transparent, hard, prismatic crystals, belonging to the rhombic system, or aggregated groups of crystals, or a white, somewhat gritty powder, permanent in the air, and having a spec, grav. of 1.957, a sour taste, and an acid reaction. When exposed to heat, in a porcelain crucible, potassium bitartrate is decom- posed, with the evolution of empyreumatic, inflammable vapors, leaving a black residue of carbon and pure potassium carbonate ; this residue, when dissolved in a little water, gives a filtrate which effervesces with acids, and forms a white, granular precipitate with an excess of tartaric acid. Potassium bitartrate is soluble in -210 parts of water at 15° C. (59° F.), and in 15 parts of boiling water, but is very sparingly soluble in alcohol, and insoluble in absolute alcohol and ether; it dissolves wholly and readily in mineral acids, as also in solu- tions of citric and oxalic acids, in dilute solutions of the alkaline hydrates and carbonates, of boracic acid, and of sodium biborate. If the aqueous solution of the salt be exactly neutralized with a solution of potassium hydrate, and a few drops of solution of argentic nitrate added, a white precipitate is produced, which becomes black on boiling. 466 MANUAL OF CHEMICAL ANALYSIS. Examination: Insoluble admixtures (such as terra alba or white clay, and similar crude adulterants) are indicated by a residue left when small samples of the powder are dissolved separately in a warm, diluted solution of potassium hydrate, and in dilute hydrochloric acid. Sulphates and chlorides are detected by agitating a small por- tion of the salt with about ten times its weight of warm water, and by testing portions of the clear liquid, when cool, and after the addition of a few drops of nitric acid, with barium nitrate for sulphates, and with argentic nitrate for chlorides. Alum.—An adulteration of powdered cream of tartar with alum is at once indicated by a greater solubility of the salt in water, by its intumescence upon incineration, and by the incom- plete solubility of the fused residue in water, as also by the odor of ammonia, and the production of white fumes from a glass rod, moistened with acetic acid, when the powder is heated with a solution of potassium hydrate, and by the formation of a white precipitate, when a few drops of this alkaline solution are allowed to fall into a dilute solution of ammonium chloride. Metallic impurities may be detected in* the solution of the salt in ammonia-water, by a dark coloration or precipitate upon the addition of ammonium sulphide. Calcium salts may be best detected when 1 gram of the salt is repeatedly agitated with 5 grams of acetic acid, at the ordinary temperature, during half an hour, the solution subsequently di- luted -with 25 grams of water, filtered, and 8 drops of solution of ammonium oxalate are added ; a white turbidity, occurring either at once or within half a minute, will indicate the presence of more than 0.3 per cent, of such impurities. Estimation: The quantitative estimation of potassium bitartrate may readily be accomplished by its conversion into carbonate, and the estima- tion of the latter by means of a normal acid. 4.70 grams of the salt are ignited in a porcelain crucible, at a red heat, until gases cease to be evolved, and the residue subse- quently dissolved in water, and filtered; the solution, together with the washings from the filter, contained in a beaker, after the addition of a few drops of litmus solution, is then titrated with a standard solution of oxalic or sulphuric acid (page 82) until, with the application of a gentle heat to expel the disengaged carbonic acid gas, a slight excess of acid has been employed, and the liquid assumes a bright cherry-red tint ; the excess of acid is then in- versely titrated with a standard solution of potassium or sodium hydrate (page 87) until the liquid just assumes a permanent blue color. If the salt be perfectly pure, 25 cubic centimeters of the normal acid solution will be required for the exact neutraliza- tion of the quantity indicated, or, the percentage purity of the 467 POTASSIUM. salt will be determined, when, for the neutralization of the above stated amount, the number of cubic centimeters of normal acid employed are multiplied by 4; one cubic centimeter of the nor- mal acid solution corresponding to 0.069 gram of potassium car- bonate, or, as its equivalent, 0.188 gram of potassium bitartrate. POTASSII BROMIDTJM. POTASSIUM SEU KALIUM BROMATUM. Ger. Bromkalium ; Fr. Brdmure de potassium ; Sp. Bromuro de potasio. Bromide of Potassium. Potassium Bromide. KBr; 118.8. Anhydrous, colorless, semi-transparent, cubical crystals, some- times elongated into prisms, or flattened to plates, permanent in the air, and of a spec. grav. of 2.69 at 4° C. (39.2° F.); when ex- posed to heat, they decrepitate, and fuse at a little below a red heat, without decomposition. When a few grains are triturated and subsequently heated, in a dry tube, with a little potassium bisulphate, yellowish-red vapors of bromine are evolved. Potassium bromide is soluble in 1.6 parts of water and in 200 parts of alcohol at 15° C. (59° F.), in 1 part of boiling water, and in 16 parts of boiling alcohol; its aqueous solution has a strong- saline taste, is neutral in its action upon litmus, and, when dropped into a very dilute solution of argentic nitrate, causes a yellowish- white, curdy precipitate, which is insoluble in dilute nitric acid, but soluble in a large excess of ammonia-water (distinction, in the latter instance, from argentic iodide); when dropped into a very dilute solution of mercuric chloride, no reaction takes place (addi- tional distinction from potassium iodide): it gives a white, granu- lar precipitate with a saturated solution of sodium bitartrate. Potassium bromide and its solution may also be distinguished from the iodide by adding to the solution a little mucilage of starch, and subsequently a few drops of chlorine-water; the solu- tion of the bromide becomes light yellow ; that of the iodide will at once assume a deep-blue color. Examination: Moisture which may be contained in the crystals, as well as in the granular form of the salt, is recognized, and may be deter- mined, by the loss of weight when the salt is dried at 100° C. (212° F.j. Potassium carbonate is detected by a white turbidity occurring upon the addition of a little of the concentrated solution of the salt to lime-water, as also by a decided alkaline reaction, when a few fragments of the salt are placed upon moistened red litmus- paper. 468 MANUAL OF CHEMICAL ANALYSIS. Sulphates may be detected, in the aqueous solution, acidulated with a few drops of diluted nitric acid, by a white precipitate with barium nitrate. Potassium bromate is detected by placing a little of the pow- dered salt upon a piece of white porcelain, and subsequently add- ing one drop of dilute sulphuric acid ; a yellow coloration of the moistened surface of the salt, or the developed odor of bromine, will reveal the presence of bromate. The presence of the latter, in an aqueous solution of the salt, may also be detected by the liberation of bromine upon the addition of a few drops of dilute sulphuric acid, imparting a yellow color, which, upon subsequent agitation of the solution with a few drops of carbon bisulphide, will be absorbed by the latter. Potassium and sodium chlorides are distinguished from potas- sium bromide, and may be recognized by adding a few drops of chlorine-water to the aqueous solution of the salt; if this is bro- mide, the mixture assumes at once a yellow color, which, how- ever, will be completely abstracted from the aqueous solution by chloroform, ether, or carbon bisulphide, when agitated therewith. This reaction does not take place with potassium or sodium chloride. If an admixture of potassium'chloride, or other salts, be sus- pected, the purity of the sample may be ascertained by preparing a solution of 1 gram of the dry, crystallized salt, in about 10 times its weight of water, acidulated with a few drops of diluted nitric acid, and completely precipitating it with a solution of argentic nitrate; the precipitate is collected upon a moist, tared filter, is washed, dried, and, when completely dry, weighed. If the salt was pure potassium bromide, the obtained argentic bromide should weigh 1.58 grams; if it contained potassium or sodium chloride, the weight, provided the salt is free from other impuri- ties, will be greater in proportion to the amount of those admix- tures, since their molecular weights are lower; 1 gram of potas- sium chloride, for instance, would give 1.92 grams of argentic chloride. The same test may also be used to indicate the purity of the bromide, by ascertaining the quantity of argentic nitrate required to precipitate completely a certain weight of potassium bromide, 1 gram of which requires 1.43 grams of argentic nitrate for pre- cipitation. The following additional methods for the detection of an ad- mixture of chlorides may also be employed. A portion of the salt, dissolved in water, is completely precipitated by argentic nitrate, the washed and still moist precipitate digested for some time with a cold, saturated solution of ammonium carbonate, sub- sequently filtered, and the filtrate supersaturated with nitric acid ; the production of a white, curdy precipitate will reveal the pres- ence of chloride. 469 POTASSIUM. The presence of much smaller amounts of chloride, and less than that admitted in the officinal salt, may be detected as fol- lows : 5 grams of the powdered and well-dried salt, together with 6 grams of pure powdered potassium bichromate, are introduced into a small flask, and 15 grams of concentrated sulphuric acid are added. The mixture is then submitted to distillation at a gentle heat, and the distillate collected in a receiver or flask con- taining a small quantity of ammonia-water (F.g. 145). Bromine Fig. 145. distils over, and is dissolved by the ammonia-water without color; but, if chlorides are present, chlorochromic anhydride, Cr02Cl2, is produced, distils over, and forms ammonium chromate, which imparts a yellowish color to the distillate ; by subsequently heat- ing the latter with a little hydrochloric acid and alcohol, the bright green color of the chromic salt will be produced. Nitrates may readily be detected, if the salt be free from bro- mate, by an ensuing intense yellow coloration, when a solution of a few fragments of the powdered salt in twenty times their weight of dilute sulphuric acid is heated to boiling. In the presence of bromate, nitrates will be indicated by the development of the odor of ammonia, when the salt, together with an equal weight of iron filings, zinc filings, and solid sodium or potassium hydrate, is gently heated, in a test-tube, with an equal volume of water. If, however, ammonium salts be originally present as an admixture, the ammonia must first be completely expelled, by heating a por- tion of the salt with a strong solution of potassium hydrate, after which, the iron and zinc filings may be added, and the test subse- quently performed for nitrates, as above described. Estimation: The estimation of potassium bromide, or the amount of chloride which may be contained therein, is most readily accomplished 470 MANUAL OF CHEMICAL ANALYSIS volumetricallv. Two grams of the potassium bromide, previously reduced to powder and carefully dried, are dissolved in water to the measure of 100 cubic centimeters. 10 cubic centimeters of this solution, corresponding to 0.2 gram of potassium bromide, are then brought into a beaker, diluted with about 50 cubic centimeters of water, and, after the addition of a few drops of a solution of potas- sium chromate, the solution is titrated with a decinormal solution of argentic nitrate (page 98) until a permanent reddish-brown col- oration is produced. If the salt is pure potassium bromide, 16.8 cubic centimeters of the silver solution will be required to pro- duce this effect, as containing 0.2856 gram of argentic nitrate, which corresponds to 0.2 gram of potassium bromide, according to the equation If the salt was pure potassium chloride, 26.84 cubic centimeters of the silver solution would be required for its complete precipitation, in ac- cordance with a similar proportion ; the difference in the amount of silver solution, required for 0.2 gram of the two salts, would therefore be 26.84 — 16.80 = 10.04 cubic centimeters; from which it follows, that for each 0.1004 cubic centimeter silver solution required in excess of 16.8 cubic centimeters, in order to effect complete precipitation. 1 per cent, of potassium chloride will be represented, as AgN03: KBr = 0.2856 : 0.2. 170 119 It is evident, that the presence of potassium iodide, or other alkaline chlorides or bromides, would influence the result in proportion to the quantity of the admixture. The United States Pharmacopoeia directs that if 3 grams of the well-dried salt be dissolved in distilled water to make 100 cubic centimeters, and 10 cubic centimeters of this solution be treated with a few drops of test-solution of potassium bichromate, and then volumetric solution of argentic nitrate be added, not more than 25.7 cubic centimeters of the latter should be consumed before the red color ceases to disappear on stirring (indicating the absence of more than 3 per cent, of chloride). —°- = 0.1004. 100 POTASSII CARBONAS CRUDUS. POTASSIUM SFU KALIUM CARBONICUM CRUDUM. Crude Carbonate of Potassium. Pearlash. Ger. Rohes kolilensaures Kalium, Pottasche ; Fr. Potasse impure ; Sp. Potasa ordinaria. White, bluish-white, or reddish-white masses (the color being dependent upon the presence of small amounts of potassium man- ganate or ferric oxide), or a coarse granular powder intermingled POTASSIUM. 471 with smaller lumps, somewhat deliquescent, and of a burning, alkaline taste and strong alkaline reaction. Water extracts from pearlash the potassium carbonate and hydrate, and the soluble impurities, the greater part of the impurities remaining behind (sulphates, chlorides, silicates, phosphates, and carbonates of calcium and aluminium); the filtered solution effervesces with acids, and yields a white, granular precipitate with an excess of tartaric acid. The examination of pearlash consists in the determination of the quantity of soluble potassium carbonate and hydrate, or the available potassium oxide. Approximate Estimation: One hundred parts of commercial pearlash, when successively exhausted with about ten times its weight of warm water, afford a solution which should neutralize at least 58 parts of sulphuric acid of 1.848 spec. grav. Volumetric Estimation: The estimation of the amount of pure potassium carbonate in pearlash, when free from alkaline hydrates and sodium carbonate, is readily accomplished as follows. 34.5 grams of the pearlash are dissolved in water to the measure of 500 cubic centimeters. Of this solution, after the insoluble impurities have subsided and the liquid has become perfectly clear, 100 cubic centimeters (cor- responding to 6.9 grams of the pearlash) are brought into a beaker or small flask, and a few drops of litmus solution are added. A standard solution of oxalic or sulphuric acid (page 82) is then allowed to flow into the liquid from a burette, until an ex- cess of the acid has been employed, and the liquid, after being heated to boiling, in order to completely expel the liberated carbonic acid gas, assumes a cherry-red color. The excess of acid is then inversely titrated with a standard solution of potassium or sodium hydrate (page 87) until a permanent blue coloration of the liquid is pro- duced. From the amount of acid required for the exact neutral- ization of the quantity of pearlash employed, the amount of pure potassium carbonate may be calculated: one cubic centimeter of the normal acid solution corresponding to 0.0692 gram of potas- sium carbonate; or, the number of cubic centimeters of the acid solution, if strictly normal, which is required for the neutraliza- tion of the above amount of the salt, will indicate at once its per- centage purity iu potassium carbonate. If the pearlash contains potassium hydrate in addition to po- tassium carbonate, which will be indicated by an alkaline reaction of the solution of the salt after its complete precipitation by barium chloride and subsequent filtration, the hydrate will also be neutralized by the acid, and the estimation of the amount of carbonate would therefore be incorrect. In the latter case, the amount of potassium hydrate and carbonate may be separately estimated according to the following method: 100 cubic centi- 472 MANUAL OF CII EM [CAL ANALYSIS. meters of the above solution (corresponding to 6.9 grams of the pearlash) are mixed with an excess of a solution of barium chlo- ride, and to the unfiltered solution, containing the deposited barium carbonate, normal nitric acid is added from a burette, until a drop of the mixture no longer produces a brown stain upon turmeric paper. The number of cubic centimeters of the acid solution which are required to produce this reaction cor- responds to the amount of potassium hydrate in the pearlash: one cubic centimeter of the normal nitric acid corresponding to 0.056 gram of potassium hydrate. The entire mixture, after the addition of a few drops of litmus solution, is then titrated, with the aid of heat, with an excess of normal nitric acid, until a cherry-red tint of the liquid is produced, and subsequently in- versely titrated with a normal alkali until the red tint of the liquid is just changed to a permanent blue. The number of cubic centimeters of the normal nitric acid which are required in the last operation, after the deduction of the normal alkali solution subsequently employed, will correspond to the amount of potassium carbonate present in the salt: one cubic centimeter of normal nitric acid corresponding to 0.069 gram of pure potassium carbonate. If sodium carbonate be also present in the pearlash, the results of the above methods of estimation will be influenced in proportion to its amount, and their correctness accordingly impaired. The estimation of the amount of sodium carbonate may also be quite readily accomplished by the following method: 10 grams of the pearlash are dissolved in 10 grams of hot water, the solution fil- tered, the filter with its contents of insoluble matter subsequently washed with 5 grams of water, and the entire filtrate finally supersaturated with acetic acid. The solution is then evaporated upon the water-bath to dryness, and the residue heated with 40 cubic centimeters of alcohol, of the spec. grav. 0.830, whereby the acetates of potassium and sodium pass into solution, and the sul- phates, chlorides, phosphates, and silicates remain undissolved. To the solution thus obtained, a solution of 21 grams of tartaric acid in 20 parts of hot water is added until, after standing for some hours, no further precipitate of potassium bitartrate is pro- duced. The mixture is then filtered, and the precipitate, con- tained upon the filter, washed with alcohol, until a few drops of the filtrate, after active agitation with a little potassium acetate, remain perfectly clear. The filtrate is subsequently evaporated to dryness, and gently ignited; a few drops of water are then added, and the operation repeated until, upon ignition, the mass becomes completely incinerated. The ignited mass is then dis- solved in water, neutralized with hydrochloric acid, and again evaporated. The sodium chloride thus obtained is dissolved in a small amount of water, a little ammonium carbonate added, and again evaporated to dryness, in order to remove the iron and aluminium, as also traces of calcium and. magnesium which may 473 POTASSIUM. be present. The dried residue is then extracted with warm water, and the solution, wh’ch now contains pure sodium chlo- ride, filtered, evaporated to dryness, ignited in a covered platinum crucible, and its weight finally determined. From the weight of the sodium chloride the amount of anhydrous sodium carbonate may readily be calculated : 100 parts of the former corresponding to 90.6 parts of the latter. When the pearlash contains both potassium and sodium car- bonates, and a determination of the relative amount of each is required, an estimation of the amount of carbonic acid contained in a weighed portion (about 2 grams) of the ignited soluble salt must be made, as described on page 86. From the total amount of carbonic acid, the amount corresponding to that of the sodium carbonate present in the salt may be deducted, when the remain- der will correspond to the percentage of potassium carbonate, and should conform with the results of the volumetric estimation. POTASSII CARBONAS DEPURATUS. POTASSIUM SEU KALIUM CARBONICUM DEPURATUM. Purified Carbonate of Potassium. Purified Pearlash. Ger. Gereinigtes kolilensaures Kalium ; Fr. Potasse purifiee ; Sp. Polasa refinada. A white, crystalline, or granular powder, permanent in a dry atmosphere, hut deliquescent in a moist one, and possessing a strongly alkaline taste and reaction ; when heated, on platinum wire, in the non-luminous flame, it communicates to the latter a violet color. Purified pearlash is soluble in 1 part of water at 15° C. (59° F.), and in 0.7 part of boiling water, forming a strongly alkaline solu- tion which frequently appears slightly turbid, and deposits gradu- ally a flocculent or gelatinous sediment of silicic acid ; it is insolu- ble in alcohol. Its aqueous solution is decomposed by acids, with effervescence, yields a white, amorphous precipitate with magne- sium sulphate, and a white, crystalline one with an excess of tar- taric acid. Purified pearlash contains about 80 per cent, of potassium car- bonate, and not more than 15 to 18 per cent, of water, which latter is lost by exposure to a red heat. Examination: Potassium hydrate is indicated in the solution of the salt, by an alkaline reaction after its complete precipitation with an excess of barium chloride, and subsequent filtration; its amount may be approximately estimated by agitating a few grams of the salt with absolute alcohol, filtering the solution, and evaporating the 2K2C03.3H20 ; 330. 474 MANUAL OP CHEMICAL ANALYSIS. filtrate, together with the alcoholic washings therefrom, to com- plete dryness, in a tared porcelain capsule; the weight of the dried residue will indicate approximately the proportion of potas- sium hydrate contained in the salt. Foreign Salts.—A small portion of the purified potassium car- bonate is dissolved in an equal weight of water, in a test-tube; the solution should be complete and limpid, or nearly so; it is diluted with an equal volume of water, filtered, and supersatu- rated with hydrochloric acid ; a gelatinous precipitate after a time would indicate silicic acid; the liquid is then filtered, and part of the filtrate supersaturated with ammonia-water, when a white tur- bidity would indicate aluminium salts; the other part of the fil- trate is tested with barium chloride for sulphate. Chloride and phosphate may be detected in the diluted solution of the salt, supersaturated with nitric acid, by testing it in two portions, with argentic nitrate for chloride, and bv supersatura- tion with ammonia-water, and the subsequent addition of test magnesium mixture, for phosphate. Sulphite and hyposulphite are detected in the filtered solution of the salt, slightly supersaturated with acetic acid, by adding a few drops of mucilage of starch, and subsequently two or three drops of diluted solution of iodinized potassium iodide; the first drop of the latter solution should produce a blue coloration at once, which will not occur before the addition of several drops, if the above impurities are contained in the salt. Sodium carbonate may be detected by a white, crystalline pre- cipitate, occurring at once or after some time, when a hot diluted solution of the potassium carbonate is nearly neutralized with acetic acid, and subsequently tested with potassium antimoniate. Metallic impurities are detected in the filtered solution of the salt, by dividing it into two parts, one of which is supersaturated with hydrochloric acid; both are then saturated with hydrogen sulphide, when any coloration or precipitate in either of the liquids would indicate the presence of foreign metals. Estimation; Water.—The percentage of water contained in the salt may be determined by its loss of weight, upon ignition in a small porce- lain crucible, at a red heat. Potassium Carbonate.—About 3 grams of the salt, accurately weighed, and previously deprived of water, by ignition at a strong heat in a small porcelain crucible, are dissolved in about 20 cubic centimeters of water, in a beaker or small flask, and a few drops of litmus solution added ; the solution having been heated to boil- ing, a standard solution of oxalic or sulphuric acid (page 82) is allowed to flow into the liquid from a burette until, with the con- tinuance of the heat to expel the liberated carbonic acid gas, a slight excess of acid has been employed, and the liquid assumes a bright cherry-red tint; the excess of acid is then inversely titrated POTASSIUM. 475 with a standard solution of potassium or sodium hydrate (page 87), until the red tint of the liquid is just changed to a permanent blue. From the number of cubic centimeters of acid solution required for the exact neutralization of the salt, the amount of pure potassium carbonate contained therein may be calculated : one cubic centimeter of the normal acid solution corresponding to 0.0692 gram of anhydrous, or 0.0825 gram of crystallized potas- sium carbonate, 2K2C03.3H20. If alkaline hydrates or sodium carbonate be present in the salt, the above method of estimation must be modified, as described in the preceding article, on pages 471 to 473. Table of the amount of dry Potassium Carbonate contained in solutions of the salt of different specific gravities. Temperature 15° C. (59° F.). Per cent, of KjCOa. Specific gravity. Per cpnt. of K„C03. Specific gravity. Per cent. , of K2C03. Specific gravity. Per cent, of K2C03. Specific gravity. 1 1.00914 14 1.13199 27 1.26787 40 1.41870 2 1.01829 15 1.14179 28 1.27893 41 1.43104 3 1.02743 16 1.15200 29 1.28999 42 1.44338 4 1.036,18 17 1.16222 30 1.30105 43 1.45573 5 1.04572 18 1.17243 31 1.31261 44 1.46807 0 1-05513 19 1.18265 j 32 1.32417 45 1.48041 7 1.06454 20 1.19286 33 1.33573 46 1.49314 8 1.07396 21 1.20344 34 1.34729 47 1.50588 9 1.08337 22 1.21402 35 1.35885 48 1.51861 10 1.09278 23 1.22450 36 1.37082 49 1.53135 11 1.10258 24 •1.23517 37 1.38279 50 1.54408 12 1.11238 25 1.24575 38 1.39476 51 1.55728 13 1.12219 26 1.25681 39 1.40673 52 1.57048 POTASSII CARBONAS PURUS. POTASSIUM SEU KALIUM CARBONICUM PURUM. Pure Carbonate of Potassium. Salt of Tartar. Potassium Carbonate. Ger. Kohlensaures Kalium ; Fr. Carbonate de potasse ; Sp. Carbonato de potasa puro. K,C03; 138. A white, deliquescent, granular powder, wholly soluble in an equal weight of water, forming a limpid alkaline liquid, which effervesces with acids, and gives a white, crystalline precipitate with an excess of tartaric acid. When exposed to a red heat, dry potassium carbonate loses about 16 per cent, of its weight. One hundred parts of the dry anhydrous carbonate require for com- plete neutralization 113 parts of citric, and 108.7 parts of tartaric, acid. MANUAL OF CHEMICAL ANALYSIS. Examination: Bicarbonate.—A small portion of the salt is dissolved in an equal weight of water, aided by dipping the test-tube in hot water ; the solution should be clear and complete, and remain so after cooling; the separation of a crystalline deposit would indicate potassium bicarbonate. The presence of the latter will also be indicated in a solution of one part of the salt in three parts of water, by the evolution of carbonic acid gas upon heating the solution to boiling. Purified Pearlasli.—A portion of the above-obtained solution is slightly supersaturated with diluted nitric acid, and allowed to stand in a corked test-tube for several hours; an ensuing gela- tinous precipitate would indicate silicic acid; the solution, after filtering, if necessary, is then tested in separate portions, with argentic nitrate for chloride, and with barium nitrate for sulphate, which impurities would indicate the admixture or substitution of purified peariash. Metals.—Another portion of the above-obtained aqueous solu- tion of the salt is tested with hydrogen sulphide in two test-tubes, the one after supersaturation with diluted hydrochloric acid. An ensuing dark coloration or precipitate in either of the fluids would indicate metallic impurities. Potassium Nitrate.—The remainder of the concentrated solu- tion of the salt is supersaturated with diluted sulphuric acid ; the Fig. 146. clear solution is decanted after a while, and divided into two parts, one of which is mixed with a little ferrous sulphate and then transferred, by means of a pipette, upon concentrated sul- phuric acid in a test-tube (Fig. 146); an ensuing purple or brown POTASSIUM. 477 coloration, at the junction of the two strata of the liquids, would indicate nitrate; the other part is tinged slightly blue with solu- tion of indigo, strongly acidulated with sulphuric acid, and heated ; ensuing decoloration would confirm the presence of nitrate. Nitrites may be detected by mixing a little of the aqueous solu- tion of the salt with an excess of dilute sulphuric acid, and subse- quently adding a few drops of a solution of potassium iodide and a little mucilage of starch; a blue coloration will reveal the pres- ence of nitrite. Potassium cyanide may be detected in the solution of the salt, by the addition of a few drops of a solution of ferrous sulphate and ferric chloride, gently warming, and subsequently slightly supersaturating the liquid with hydrochloric acid; the immediate or gradual formation of a precipitate of Prussian blue will con- firm the presence of alkaline cyanide. Calcium and magnesium salts, when present in the form of carbonates, will remain undissolved when the potassium carbonate is treated with twenty times its weight of water; they may be otherwise detected in the aqueous solution, previously neutralized with hydrochloric ac’d, by the addition of ammonia-water, ammo- nium chloride, and ammonium oxalate; a white precipitate will indicate the presence of calcium; the filtrate from the latter, or the clear liquid if no precipitate was produced, is then tested with sodium phosphate, when the formation of a white, crystalline pre- cipitate will reveal the presence of magnesium. Sodium salts will be indicated, by their property of imparting a persistent yellowr color to the non-luminous flame; the carbonate may be specially tested for by supersaturating the aqueous solu- tion of the salt with acetic acid, evaporating to dryness, and extracting the residue with absolute alcohol; the filtered alcoholic liquid is then evaporated to dryness, the residue dissolved in wrater, and a solution of potassium meta-antimoniate added; if sodium carbonate were present, a white, crystalline precipitate of sodium meta-antimoniate will be produced. Estimation: The estimation of pure potass'um carbonate may readily be ac- complished by the method described under purified pearlash, on pages 474-475. The United States Pharmacopoeia directs that to neutralize 3.45 grams of potassium carbonate should require not less than 40.5 cubic centimeters of the volumetric solution of oxalic acid (corresponding to at least 81 per cent, of pure, anhydrous potas- sium carbonate). 478 MANUAL OF CHEMICAL ANALYSIS. POTASSII CHLORAS. POTASSIUM SEU KALIUM CHLORICUM. Chlorate of Potassium. Potassium Chlorate. Ger. Clilorsaures Kalium ; Fr. Chlorate de potasse; Sp. Clorato de potasa. KC]03; 122.4. Colorless, transparent, rnonoclinic prisms or tables (Fig. 14 i), of a pearly lustre, anhydrous, and permanent in the air, and of a spec. gray, of 2.36 at 17.5° C. (63.5° F.); when thrown upon burning charcoal they deflagrate, as they also do more or less violently when triturated or heated with readily combustible substances, as sul- phur, carbon, phosphorus, etc. Potassium chlorate melts at 334° C. (633.2° F.) with- out decomposition; at 352° C. (665.6° F.) it begins to decompose with the evolu- tion of oxygen, and at 400° C. (752° F.) the entire amount of oxygen (39.2 per cent, by weight) is liberated, leaving be- hind a neutral residue of potassium chloride (60.8 per cent.), which is wholly soluble in water. The aqueous solution of this residue yields a white, crystalline precipitate with a concentrated solution of sodium bitartrate, and a white, curdy precipitate, soluble in ammonia-water, with argentic nitrate. When a little sulphuric acid is dropped on the crystals of the chlorate, they become first yellow and then orange-red; with concentrated hydro- chloric acid the salt becomes likewise decomposed, with the libera- tion of chlorine and chlorine dioxide; the latter, in contact with an excess of acid, becoming subsequently decomposed into chlo- rine and water. Potassium chlorate is soluble in 16.5 parts of water at 15° C. (59° F.), in 2 parts of boiling water, and in 120 parts of alcohol of 0.835 spec. grav. Its saturated aqueous solution has a cooling, saline, slightly acerb taste, and, when mixed with concentrated hydrochloric acid, produces a deep greenish-yellow coloration, with the evolution of chlorine gas. When a few drops of a con- centrated solution of potassium chlorate, and subsequently a little concentrated sulphuric acid, are added to a little of a dilute solu- tion of aniline sulphate, upon a watch-glass, the mixture assumes a brilliant deep-violet color. With solution of tartaric acid, the concentrated solution of potassium chlorate give a white granular precipitate. Examination: Potassium Nitrate.—A little of the powdered salt is heated in a porcelain crucible to a full red heat; the residue, when cool, is Fig. 147. POTASSIUM. 479 dissolved in a few drops of water, and the solution tested with turmeric-paper; a brown discoloration of the paper would indi- cate an admixture of potassium nitrate. As a confirmatory test, a few drops of the solution of the residue may be added to a solu- tion of mercuric chloride; an ensuing yellow precipitate will confirm the presence of nitrate. The presence .of nitrate may also readily be detected by first heating a small portion of the salt, in a test-tube, with about twice its weight of solid potassium or sodium hydrate, and a little water, in order to ascertain the absence of ammonium salts, and subse- quently adding a few iron and zinc filings, and again heating; if ammonium salts were found to be absent, or have been com- pletely eliminated by the previous heating with caustic alkali, the odor of ammonia, developed upon the addition of the zinc and iron, will confirm the presence of nitrate. Potassium, chloride and sulphate are detected in the aqueous solution, acidulated with a few drops of diluted nitric acid, by the occurrence of a white precipitate, in the case of the former with argentic nitrate, of the latter with barium nitrate. Most commercial potassium chlorate occasions a slight cloudi- ness with argentic nitrate. Calcium salts maybe detected in the dilute aqueous solution of the salt, by a white precipitate upon the addition of a few drops of a solution of ammonium oxalate. Sodium chlorate will be indicated in the salt by its property of imparting a persistent yellow color to the non-luminous flame, as also by its much greater solubility in water and warm alcohol. It may be extracted by treating a portion of the salt with boiling- alcohol, filtering, and adding to the filtrate a concentrated solu- tion of tartaric acid ; the potassium will thereby be precipitated, and, after its complete deposition, the filtrate may be further examined for sodium. Metallic impurities may be detected in the aqueous solution of the salt, acidulated with hydrochloric acid, by a dark coloration or precipitate upon saturation with hydrogen sulphide, or, after neutralization with ammonia-water, by the addition of ammonium sulphide. POTASSIUM SEU KAL1UM CITRICUM. POTASSII CITRAS. Citrate of Potassium. Potassium Citrate. Ger. Citronensanres Kalium ; Fr. Citrate de potasse ; Sp. Citrato de potasa. KAH.07 + Ht0; 824. A white, granular powder, or transparent prismatic crystals, containing one molecule (5.55 per cent.) of water; it is deliques- 480 MANUAL OF CHEMICAL ANALYSIS. cent upon exposure to the air, odorless, of a slightly cooling and faintly alkaline taste, and neutral in its action upon litmus. When moderately heated, the salt loses its water, at a higher tempera- ture it chars, and at a red heat becomes completely decomposed, with the evolution of inflammable vapors, leaving a black residue, consisting of potassium carbonate and carbon, which strongly effervesces with acids. Potassium citrate is soluble in 0.6 part of water at 15° C. (59° F.), and is very soluble in boiling water; it is very sparingly soluble in alcohol. Its aqueous solution yields a white, crystal- line. precipitate upon the addition of a concentrated solution of sodium bitartrate; upon the addition of a cold solution of cal- cium chloride the liquid remains clear, but, upon boiling, a white, granular precipitate is produced, which redissolves for the most part upon cooling. Examination: Potassium tartrate will be indicated by the separation of a white, crystalline precipitate, upon the addition of acetic acid to a concentrated aqueous solution of the salt. Carbonates, Sulphates, and Chlorides.—The aqueous solution of the salt is slightly acidulated with nitric acid, when effervescence will indicate carbonates; the acidulated solution is then subse- quently tested, in separate portions, with barium chloride for sulphates and with argentic nitrate for chlorides, when an ensuing- white precipitate in either instance will reveal the presence of such impurities. Metallic impurities may be detected in an aqueous solution of the salt, acidulated with hydrochloric acid, by a dark coloration or precipitate upon saturation with hydrogen sulphide, or, after supersaturation with ammonia-water, by the addition of ammo- nium sulphide. Estimation: Potassium citrate may be estimated volumetrically its con- version into potassium carbonate, and the neutralization of the latter by means of a normal or standard acid. 5A grams of the salt are ignited in a porcelain crucible, at a red heat, until gases cease to be evolved; the soluble matter of the residue is then completely extracted with hot water, the solution filtered into a beaker or small flask, a few drops of litmus solution added, and a standard solution of oxalic or sulphuric acid (page 82) allowed to flow into the liquid from a burette until, after being heated to boil- ing, in order to completely expel the liberated carbonic acid gas, the liquid assumes a bright cherry-red tint. The excess of acid is then inversely titrated with a standard solution of potassium or sodium hydrate (page 87) until the red tint of the liquid is just changed to a permanent blue. If the above amount of the salt is employed, the number of cubic centimeters of normal acid which POTASSIUM. 481 is required for its neutralization, when multiplied by 2, will rep- resent without further calculation its percentage purity. With the employment of other quantities of the salt than that above indicated, the calculation maybe made with the consideration that one cubic centimeter of normal acid corresponds to 0.108 gram of potassium citrate, 4- II20. POTASSIUM SEU KALIUM CYANATUM. POTASSII CYANIDUM. Cyanide of Potassium. Potassium Cyanide. Ger. Cyankalium ; Fr. Cyanure de potassium ; Sp. Cianurode potasio. White, opaque, amorphous masses, or a white, granular, deli- quescent powder, having a sharp, somewhat alkaline taste, and a strongly alkaline reaction. It is odorless when perfectly dry, but emits the odor of hydrocyanic acid upon exposure to a moist atmosphere, in consequence of the absorption of water and car- bonic acid gas, and the liberation of hydrogen cyanide. When exposed to a low red heat, with exclusion of the air, the salt is readily fusible without decomposition, and, upon slowly cooling, solidities in the form of cubical crystals; when heated with exposure to the air, it absorbs oxygen, and becomes partially converted into potassium cyanate. It is decomposed by all acids, with the disengagement of hydrocyanic acid. Commercial potassium cyanide is soluble in 2 parts of water at 15° C. (59° F.), and in its own weight of boiling water; it is but sparingly soluble in strong alcohol, but is quite freely soluble in boiling diluted alcohol, and crystallizes from the latter solution upon cooling. The aqueous solution has an alkaline reaction, exhales the odor of hydrocyanic acid, and becomes gradually decomposed by exposure to the air; upon boiling, it is rapidly decomposed, with the evolution of ammonia, and the formation of potassium formiate. The aqueous solution of potassium cya- nide yields a white, crystalline precipitate upon the addition of a concentrated solution of sodium bitartrate ; with argentic nitrate, it yields a white precipitate, which is soluble in an excess of potas- sium cyanide or of ammonia-water; and with a few drops of a solution of a ferrous and ferric salt, and the subsequent addition of hydrochloric acid in slight excess, a precipitate of Prussian blue is produced. It produces precipitates in solutions of the salts of most of the heavy metals, which, however, for the most part, are soluble in an excess of potassium cyanide, with the formation of crystallizable double salts. KCN; 65. 482 MANUAL OF CHEMICAL ANALYSIS. The detection and isolation of potassium cyanide in subjects of forensic investigation depends upon the elimination of hydrocyanic acid in contact with stronger acids, and the same method is there- fore to be pursued, and the same precautions observed, as described in detail under hydrocyanic acid, on pages 161 to 163. Examination: Potassium carbonate, which is usually present in small amount, will be indicated in the aqueous solution of the salt bv efferves- cence upon the addition of dilute hydrochloric acid. The acidu- lated solution thus obtained may subsequently be tested with a drop of a solution of ferric chloride ; a blue precipitate will indi- cate ferrocuani.de, a deep blood-red coloration, sulphocyanide. Estimation: Since commercial potassium cyanide always contains a greater or less amount of impurities, and as its value depends upon the percentage amount of pure cyanide, the determination of the latter becomes necessary, and may be readily accomplished volurnetri- callv by the following method, the principles of which have been explained on pages 100-101. 0.65 gram of the salt is dissolved in about 100 cubic centime- ters of water, in a beaker, a few drops of a solution of potassium hydrate added, or sufficient to impart to the liquid a distinct alka- line reaction, and subsequently a few drops of a saturated solution of sodium chloride. A decinormal solution of argentic nitrate (page 98) is then allowed to flow into the liquid from a burette until, with constant stirring, a permanent cloudiness of the liquid is just produced. The number of cubic centimeters of silver solu- tion which is required to produce this effect, with the employ- ment of the above-stated amount of potassium cyanide, when multiplied by 2, will represent the percentage purity of the salt. With the employment of other amounts of the salt than that above stated, the calculation may be made with the consideration that one cubic centimeter of the decinormal silver solution, in accordance with the described process, corresponds to 0.013 gram of pure potassi-um cyanide. The United States Pharmacopoeia directs that if 0.65 gram of potassium cyanide be dissolved in 12 cubic centimeters of water, and volumetric solution of argentic nitrate be gradually added, the precipitate first formed should dissolve on stirring, and a per- manent. precipitate should not appear until at least 45 cubic centb meters of the volumetric solution have been used (corresponding to at least 90 per cent, of pure potassium cyanide). POTASSIUM. 483 POTASSII ET SODII TARTRAS. POTASSIUM ET SODIUM TARTARICUM. NATRIO - KALIUM TARTARICUM. SODIUM TARTARATUM. TARTARUS NATRO- NATUS. Rochelle Salt. Seignette Salt. Potassium and Sodium Tartrate. Ger. Weinsaures Kalium-Natrium ; Fr. Tartrate de potasse et de soude ; Sp. Tartrato de potasa y sosa. KNaC.II.O, + 4H„0 = 4 4 0 2 CH(OH)-CO-OK - v ; CH(OH)-CO-ONa 4- 4H20; 282. Large, colorless, transparent, prismatic crystals, belonging to the rhombic system, the faces of which are unequally developed (Fig. 148); they contain four molecules (25.53 per cent.) of water of crystallization, and are slightly efflorescent in dry air. The salt occurs in commerce generally ground, as a snow-white powder. When quickly heated to about 75° C. (167° F.), it melts in its water of crystallization, and at 100° C. (212° F.) loses 3 molecules of water, the remaining molecule of water being elimi- nated at 130° C. (266° F.), at which tempera- ture the salt begins to decompose ; at a higher temperature it chars and is decomposed, with the evolution of inflammable vapors and the odor of burnt sugar, and, on moderate ignition, leaves a blackened residue, which consists of a mixture of potas- sium and sodium carbonates with carbon, and which colors tur- meric-paper brown, effervesces with acids, and imparts a yellow color to the non-luminous flame when heated upon the looped end of a platinum wire (distinction from potassium tartrate). Potassium and sodium tartrate is soluble in 2.5 parts of water at 15° C. (59° F.), and in much less than its own weight of boil- ing water, but is insoluble in alcohol; its aqueous solution is neutral, has a mild, cooling, saline taste, and forms a white, gran- ular precipitate with acids and with solutions of acidulous salts. When dissolved in 8 parts of water, and dilute acetic acid is added to the liquid, a white, crystalline precipitate is gradually produced (distinction from sodium tartrate); with argentic nitrate it yields a white precipitate, which becomes black on boiling. Examination: A portion of the salt is dissolved in three times its weight of warm water; the solution should be clear and complete, and remain so after cooling; it should not act upon litmus-paper, nor effervesce upon the addition of hydrochloric acid (evidence of the absence of sodium carbonate or bicarbonate). Fig. 148. 484 MANUAL OF CHEMICAL ANALYSIS. Chlorides and sulphates may be detected by a white precipitate when the diluted solution of the salt, acidulated with nitric acid, is tested in separate portions, with argentic nitrate for the former, and with barium nitrate for the latter. In case the solution sepa- rates granular potassium bitartrate upon the addition of the acid, sufficient hot water is added to redissolve the precipitate before adding the reagent. Calcium salts are detected in the diluted solution, by means of ammonium oxalate. Ammonium salts may be detected by the odor of ammonia, when the salt is heated, in a test-tube, with a solution of potas- sium or sodium hydrate, and by the development of white fumes, when a glass rod, moistened with acetic acid, is held over the mouth of the tube. Metallic impurities are detected in the concentrated solution of the salt, acidulated with hydrochloric acid, and filtered, if neces- sary, by a dark coloration or precipitate upon saturation with hydrogen sulphide, or, after neutralization with ammonia-water, by the addition of ammonium sulphide. Crystallized potassium and sodium tartrate, being in appearance somewhat similar to crystallized borax and alum, and therefore liable to incidental mistake, may readily be distinguished from either of these substances, in addition to its physical characters, b\r its taste, by its neutral reaction—alum being acid, borax line, and by the black alkaline fuse upon incineration, while both borax and alum swell up to a porous mass, and yield a white or colorless fuse. Estimation: 3.525 grams of the salt are ignited in a porcelain crucible, .at a red heat, until gases cease to be evolved ; the alkaline residue is then extracted with warm water, the solution filtered into a beaker, a few drops of litmus solution added, and titrated, by the aid of heat, with a standard solution of oxalic or sulphuric acid (page 82), as described under potassium carbonate, on page 474. The num- ber of cubic centimeters of the normal acid solution which is thus required for the exact neutralization of the liquid, when multiplied by 4, will indicate, without further calculation, the percentage purity of the salt. By the employment of other quan- tities of the salt than precisely that above stated, the calculation may also readily be made with the consideration that one cubic centimeter of the normal acid solution corresponds to 0.141 gram of pure crystallized potassium and sodium tartrate. 485 POTASSIUM. POTASSII PERROCYANIDUM, POTASSIUM SEU KALIUM FERROC YANATUM. Ferrocyanide of Potassium. Yellow Prussiate of Potassium. Potassium Ferrocyanide. Ger. Ferrocyankaiium ; Fr. Cyanure de fer et de potassium ; Sp. Ferrocianuro de potasio. K4Fe(CJST)fi4-3H20; 421.9. Large, translucent, yellow, tabular crystals, derived from an octahedron with a square base (Fig. 149); they cleave with facility in a direction parallel to the base of the octa- hedron, have a peculiar toughness and flexi- bility, and the specific gravity 1.83. The crystals contain three molecules (12.79 per cent.) of water of crystallization, and undergo no alteration in pure air at ordinary tempera- tures, but when heated to 60° C. (140° F.) they begin to lose their water of crystalliza- tion, which is completely eliminated at 100° 0. (212° F.), leaving the anhydrous salt in the form of a white powder; the latter, upon exposure to a red heat, is decomposed with the evolution of nitrogen, leaving a residue consisting of ferric carbide and potas- sium cyanide. When heated with dilute sulphuric acid, hydro- cyanic acid is evolved. Potassium ferrocyanide is soluble in 4 parts of water at 15° C. (59° F.), and in 2 parts of boiling water; it is insoluble in alcohol. Its aqueous solution has a mild saline taste, gives a white, granu- lar precipitate with a saturated solution of sodium bitartrate, and, when diluted,-a blue one with ferric, a brick-red one with cupric, and a white one with ferrous and with plumbic salts; it is not acted upon by hydrogen sulphide or ammonium sulphide, by tan- nic acid, nor by the alkaline hydrates and carbonates. When the solution is exposed for some time to the action of light, Prussian blue is deposited, and, by long-continued boiling, with exposure to the air, ammonia is given off, and the liquid becomes alkaline. Examination: Foreign salts are indicated when the potassium ferrocyanide does not yield a complete and clear solution with four parts of water. Carbonate is indicated by effervescence of the concentrated solu- tion upon the addition of acetic acid, or upon placing fragments of a crystal in diluted sulphuric acid. Sulphate is detected, in the diluted solution, acidulated with nitric acid, by a white turbidity with barium nitrate. Chloride may be detected, when a mixture of 1 part of the ex- siccated salt with 3 parts of potassium nitrate (free from chloride) Fig. 149. MANUAL OF CHEMICAL ANALYSIS. and 10 parts of anhydrous sodium carbonate is heated nearly to redness in a porcelain crucible; when cool, the whole is dissolved in water, the filtered solution supersaturated with nitric acid, and tested with argentic nitrate, which will indicate chloride by a white precipitate. POTASSII HYDRAS. POTASSA. POTASSIUM SEU KALIUM HYDRICUM PURUM. KALI CAUSTICUM. Pure Caustic Potash. Potassa. Potassium Hydrate. Ger. Kaliumliydroxyd, Aetzkali; Fr. Potasse caustique ; Bp. Hidrato de potasa. KOH; 56. A white, opaque, granular powder, or, when fused, white, semi- transparent plates or cylindrical sticks, of a fibrous fracture; exposed to the air, it absorbs water and carbonic acid, and grad- ually deliquesces. It melts below a red heat to a clear oily liquid, and volatilizes unchanged, in the form of white vapors, when more strongly ignited; when introduced into the non-luminous flame, it imparts to the latter a violet color. Potassium hydrate is soluble in 0.5 part of water and in 2 parts of alcohol at 15° C. (59° F.), with the evolution of heat, and is slightly soluble in ether ; when the concentrated aqueous solution is cooled, the hydrate, K0H-f2II20, is deposited in transparent, colorless, acute rhombohedral crystals. Its aqueous solution has a soapy feel, a burning, corrosive taste, and a strong alkaline' re- action ; it gives a grayish-brown precipitate with argentic nitrate, soluble in ammonia-water, and precipitates from their solutions most metallic oxides, several of which are redissolved by an excess of the potassium hydrate; when dropped into solution of tartaric acid, it produces a white, crystalline precipitate, which is redissolved by an excess of the alkali; it decomposes ammonium salts with the evolution of ammonia. Examination: Potassium hydrate must afford a clear and nearly complete solution when treated with about five times it weight of alcohol; the insoluble residue will be in proportion to the amount of foreign salts present. Sodium hydrate, although usually present in small amount, may be detected when contained in any considerable proportion by the following method. A weighed amount of potassium hydrate is dissolved in ten times its weight of water, the solution exactly neutralized with tartaric acid, and subsequently as much tartaric acid again added as was required for the neutralization of the POTASSIUM. 487 alkali; the solution is then diluted with alcohol until the separa- tion of potassium bitartrate no longer ensues, and finally filtered. The solution, which will contain the sodium in the form of bitar- trate, is evaporated to dryness, the residue ignited, and the ignited mass, consisting of sodium carbonate and carbon, dissolved in water, and filtered. The filtered solution, after neutralization with nitric acid, will then afford upon evaporation rhombohedral crystals of sodium nitrate, which impart a yellow color to the non-luminous flame. The amount of sodium hydrate may also be quantitatively determined, by the neutralization of a definite amount of the sodium bitartrate solution with a normal solution of potassium or sodium hydrate (page 82). The number of cubic centimeters of normal alkali solution which is required for this purpose will be in direct proportion to the amount of sodium hydrate contained in the solution under examination. Silicates, as also many foreign salts, will be indicated by a pre- cipitate, or by the separation of a heavy aqueous layer, when a solution of the potassium hydrate in two parts of water is dropped into alcohol. Carbonate may be detected when portions of a concentrated aqueous solution of the hydrate are dropped severally into acetic acid and into lime-water ; effervescence with the acid, and a white turbidity with the lime-water, would indicate carbonate. Nitrate is indicated by ensuing decoloration of the liquid when a little of the aqueous solution which has been mixed with an excess of dilute sulphuric acid, and tinted blue with one drop of indigo-solution, is gently heated. Chloride and sulphate are detected in the diluted solution, super- saturated with dilute nitric acid, by testing it, in separate por- tions, with argentic nitrate for chloride, and with barium nitrate for sulphate. Aluminium salts and phosphoric acid may be detected in the diluted solution, after supersaturation with hydrochloric acid, by the addition of ammonia-water in slight excess, and after filtering, if a precipitate be formed, by the subsequent addition of test mag- nesium mixture; a white, gelatinous precipitate with the ammo- nia-water would indicate aluminium salts, and a white, crystalline one wdth the latter reagent, occurring at once or after several hours, phosphoric acid. Metallic impurities are detected by a dark coloration or tur- bidity of the solution, when saturated with hydrogen sulphide, and, in another portion of the solution, after previous supersatu- ration with hydrochloric acid. Estimation: 2.8 grams of dry potassium hydrate are dissolved in about 20 cubic centimeters of water, in a beaker, a few drops of litmus solution added, and a standard solution of oxalic or sulphuric acid (page 82) allowed to flow into the liquid from a burette, 488 MANUAL OF CHEMICAL ANALYSIS. until the blue tint of the liquid is just changed to a permanent pink. The number of cubic centimeters of normal acid solu- tion which is thus required for the exact neutralization of the above amount of potassium hydrate, when multiplied by 2, will represent, without further calculation, its percentage purity. By the employment of other amounts of the hydrate, the calcula- tion may readily be made, with the consideration that one cubic centimeter of the normal acid solution corresponds to 0.056 gram of pure potassium hydrate. If the potassium hydrate contains carbonate, the above estima- tion will only be strictly correct, when in a weighed amount of the hydrate the amount of carbonic acid is determined, as de- scribed on pages 85-86; for 1 part of carbonic acid, 2.545 parts of potassium hydrate are deducted from the found amount of the latter, and the remainder then calculated as pure potassium hydrate. For the determination of the strength of aqueous solutions of potassium hydrate, as based upon the specific gravity of the latter, see Liquor Potassee, page 410. POTASSII HYDRAS CRUDUS. POTASSIUM SEU KALIUM HYDRICUM CRUDUM. Ger. Rohes Aetzkali; Fr. Potasse caustique impure ; Sp. Hidrato de potasa ordinaria. Crude Potash. Fused, heavy, compact masses, of a stony appearance, fracture, and hardness, of a soapy feel, burning, corrosive taste, and a destructive action on vegetable and animal matters ; its color is mostly greenish or brownish-gray ; it is deliquescent, and rapidly absorbs water and carbonic acid. Heated to redness, it fuses, but remains unchanged; at a very high heat it is volatile. Crude potash dissolves, for the most part, in water and in alco- hol, with evolution of heat, leaving a more or less considerable residue of impurities ; the decanted solution gives a grayish brown precipitate with argentic nitrate, soluble upon the addition of ammonia-water. The insoluble impurities of crude potash consist chiefly of car- bonates, sulphates, silicates, chlorides, and ferric and manganic oxides. Examination: In order to ascertain the nature of the impurities, a portion of the crude potash is triturated and dissolved in twice its weight of tepid water, and the whole is allowed to subside in a conical POTASSIUM. 489 glass vessel; the clear solution is then mixed with twice its volume of strong alcohol, and the mixture allowed to stand for several hours; the solution is then decanted from the precipitate, as far as practicable, and the latter dissolved in hot water; when cool, this solution is filtered, and the insoluble residue washed with a little water, and preserved upon the filter for further examination. The obtained aqueous solution may be examined as follows: Carbonate and silicate are recognized on dropping a little of the solution into a test-tube containing a mixture of equal parts of water and concentrated nitric acid; the former will be indicated by effervescence, the latter by a white, gelatinous turbidity, ensu- ing at once or after some hours. Sulphate and chloride may be detected, in separate portions of the solution, by supersaturating it with nitric acid, and subse- quently testing with barium nitrate for sulphate, and with argentic nitrate for chloride. Sulphite and hyposulphite are indicated by the occurrence of an insoluble residue, when a portion of the solution is precipitated with argentic niti*ate, and the precipitate is treated with ammonia- water. Nitrate is detected, in a portion of the solution, after the ad- dition of an excess of dilute sulphuric acid and one drop of solu- tion of indigo; the blue tint will disappear upon warming, if nitrate be present. Phosphate may be detected by a white, crystalline precipitate, when the solution is supersaturated with hydrochloric acid, then mixed with an equal volume of ammonia-water, and subsequently tested with magnesium sulphate. Metallic impurities are recognized by a dark coloration or pre- cipitate, wrheti both the alcoholic solution and the aqueous solu- tion of the residue from the alcoholic one are tested separately with hydrogen sulphide, as also after having been previously supersaturated with hydrochloric acid. The residue remaining from the solution in alcohol, and pre- served upon the filter, is washed with a few drops of alcohol, then dissolved upon the filter in diluted hydrochloric acid, and subse- quently neutralized with ammonia-water; this solution is then tested, in separate portions, with ammonium oxalate for calcium, and with barium chloride and a few drops of hydrochloric acid for sulphate. The estimation of crude potash may be accomplished volu- metrically by the method described for pure potassium hydrate, on pages 487-488. 490 MANUAL OF CHEMICAL ANALYSTS. POTASSII HYPOPHOSPHIS. POTASSIUM SEU KALIUM HYPOPIIOSPHOROSUM. Hypophosphite of Potassium. Potassium Hypophosphite. Ger. Unterpliosphorigsaures Kalium ; Fr. Hypophosphite de potasse ; Sp. Hipofosfito de potasa. KII2P02; 104. White, opaque, crystalline masses, or hexagonal tables, or a white granular powder, very deliquescent, and neutral in its action upon litmus; when heated in a perfectly dry test-tube, the salt first loses adhering moisture, then evolves spontaneously inflammable hydrogen phosphide, and burns with a bright yellow flame; when evaporated to dryness, in contact with nitric acid, it detonates violently. Potassium hypophosphite is soluble in 0.6 part of water, and in 7.3 parts of alcohol at 15° C. (59° P.); in 0.3 part of boiling water, and in 3.6 parts of boiling alcohol; but is insoluble in ether. The aqueous solution possesses a sharp, saline, and slightly bitter taste, and yields a white, crystalline precipitate on the addition of a concentrated solution of sodium bitartrate ; with argentic nitrate it yields a white precipitate, which rapidly turns brown and black with the separation of metallic silver; when acidulated with hydrochloric acid, and added to excess of solution of mer- curic chloride, it first produces a white precipitate of mercurous chloride (calomel), and, on further addition, metallic mercury is separated. Examination: Calcium salts will be detected by an ensuing white precipitate on the addition of ammonium oxalate to an aqueous solution of the salt. Carbonates will be detected by effervescence of the solution on the addition of an acid. Chlorides and sulphates will be detected in the aqueous solution of the salt, acidulated with nitric acid, by a white precipitate when tested, in separate portions, with argentic nitrate and barium chloride. Phosphates will be indicated in the aqueous solution of the salt by the formation of a white crystalline precipitate, either at once or upon standing, on the addition of test magnesium mixture. POTASSIUM. 491 POTASSII IODIDUM. POTASSIUM SEU KALIUM IODATUM. Iodide of Potassium. Potassium Iodide. r Ger. Jodkalium ; Fr. Iodure de potassium ; Sp. Ioduro de potasio. KI; 165.6. Colorless, anhydrous, semi-transparent, or opaque crystals, cubical, or sometimes elongated in form, permanent in dry, but slightly deliquescent in moist, air, and having a spec. grav. of 2.97. When exposed to heat, potassium iodide decrepitates, and fuses below a red heat; on cooling, it solidifies into a crystalline, pearly mass, without loss of weight, except humidity ; at a full red heat, it is slowly volatilized, without decomposition. When a few fragments of the salt are heated in concentrated sulphuric acid, or, in a dry test-tube, with a little potassium bisulphate, violet-colored vapors of iodine are evolved; and when dissolved in a little water, a few drops of chlorine-water added, and the mixture subsequently shaken with half its volume of chloroform or carbon bisulphide, these will acquire a purple or violet color. Potassium iodide is soluble in 0.8 part of water, in 18 parts of alcohol, of 0.835 spec, grav., and in 40 parts of absolute alcohol at 15° C. (59° F.), in 0.5 part of boiling water, and in 6 parts of boiling alcohol, and is also very freely soluble in warm anhydrous glycerin. The aqueous solution possesses a pungent, saline taste, a neutral or feebly alkaline reaction, and gives, with an excess of tartaric acid, a white, granular precipitate; with argentic nitrate, a yellowish one, which is insoluble in diluted nitric acid, and almost insoluble in ammonia-water, but becomes white with the latter; and a vermilion-red precipitate with mercuric chloride, soluble in an excess of either the solution or the reagent; it gives a violet-blue color with a little mucilage of starch, upon the sub- sequent addition of a few drops of chlorine-water (distinction from potassium bromide and chloride), and a white, crystalline precipitate with a saturated solution of sodium bitartrate. Examination: Water, which may be contained as interstitial moisture in the crystals, is recognized, and may be quantitatively determined, by the loss of weight upon drying a known weight of the powdered salt at 100° C. (212° F.). Impurities and Admixtures.—In order to obtain for examina- tion an average representation of the iodide, several grams of smaller and larger crystals are selected from the bulk of the salt, and triturated to agranular powder, part of which may serve for the following tests: One gram of it is dissolved in an equal weight of water; the solution formed must be clear and complete, and remain so after the addition of several times its volume of strong 492 MANUAL OF CHEMICAL ANALYSIS. or absolute alcohol; an ensuing turbidity or crystalline deposit would indicate foreign salts (carbonate, sulphate, iodate, nitrate); if this precipitate is considerable, it may be collected upon a filter, washed with a few drops of alcohol, and then dissolved in a few drops of warm water; the obtained solution may be tested for carbonate with turmeric-paper, or by allowing one or two drops of it to fall into concentrated hydrochloric acid; a brown colora- tion of the paper, and effervescence with the acid, will indicate the presence of carbonate; the rest of the solution is acidulated with a few drops of hydrochloric acid, and tested for sulphate with one drop of barium chloride, and subsequently, for nitrate, by the addition of a little sulphuric acid and a drop of indigo solution, and heating. Potassium iodate may be detected in the aqueous solution of the salt, by adding a few drops of mucilage of starch, and then a few drops of a concentrated solution of tartaric acid, insufficient to cause a precipitate; if iodate be contained in the salt, a violet coloration of the liquid will occur at once. Or the aqueous solu- tion, mixed with a few drops of concentrated solution of tartaric acid, may be shaken with a little chloroform, which will assume a red color when iodate is present. Iodate may also be recognized in potassium iodide by dropping a crystal of tartaric acid into a strong solution of the iodide in previously boiled, distilled water, and allowing it to remain at rest for several minutes; if iodate be present, the crystal will be enveloped after that time in a yellowish-white zone. Carbonate may be detected by a white turbidity when the aqueous solution of the potassium iodide is mixed with twice its volume of lime-water, and will also be indicated by a strongly alkaline reaction, when a few fragments of the salt are placed upon moistened red litmus paper. Sulphate may be detected in the diluted solution of the iodide, previously acidulated with hydrochloric acid, by a white precipi- tate with barium chloride. Nitrate may be detected in the aqueous solution, if the salt be free from iodate, by the addition of a few drops of mucilage of starch, and subsequently adding a little of this liquid to a mix- ture of zinc and dilute hydrochloric acid, in which the develop- ment of hydrogen is actively taking place; if any nitrate be pre- sent, the liquid will gradually assume a reddish-violet or blue color. If iodate be present, the presence of nitrate may also be determined bv completely precipitating a solution of the salt with argentic sulphate, filtering, and adding to the filtrate, in a test- tube, a concentrated solution of ferrous sulphate, and afterwards concentrated sulphuric acid, so as to form two layers (Fig. 146, p. 476); a dark-brown coloration at the line of contact of the two liquids will then reveal the presence of nitrate. Chloride and bromdde are detected by dissolving 1 gram of the salt in 10 grams of ammonia-water, and agitating the solution POTASSIUM. 493 with a solution of 1.1 grams of argentic nitrate in 20 grams of water ; the mixture is then filtered, and the filtrate super- saturated with 8 grams of strong nitric acid; since ammonia- water dissolves onty traces of argentic iodide, the transparency of the liquid must be not at all, or only slightly, impaired; a white turbidity, subsiding to a precipitate, would indicate the presence of more than about 0.5 per cent, of chloride or bromide. In order to distinguish these, the precipitate is collected upon a filter and washed with a little water, until this ceases to redden blue litmus- paper; the filter is then pierced by a glass rod, and the precipi- tate rinsed into a test-tube; after subsidence, the Avater is, as far as possible, decanted, and chlorine-water added and agitated with the precipitate; since chlorine decomposes argentic bromide, dis- solving the disengaged bromine with a yellow color, bromide will be recognized by a more or less deep yellow color of the fluid, while argentic chloride remains unchanged. When chloroform or ether is then added to the fluid and agitated, it will absorb the bromine and the yellow color from the water. A confirmatory test for the recognition of bromide is, to add to a solution of the salt an excess of solution of cupric sulphate, and subsequently so much of a saturated solution of sulphurous acid as to impart its strong odor to the mixture, and until the brownish color of the mixture has disappeared; the liquid is then filtered, a little chloroform added, and subsequently chlo- rine-water in very slight excess, in order to effect the oxidation of the sulphurous acid, and the mixture well agitated; after sub- sidence has taken place, a yellow color will have been imparted to the chloroform if bromide is contained in the salt. Iron and zinc may be detected in the aqueous solution of the salt by the addition of a few drops of a solution of potassium ferrocyanide; a blue coloration will reveal the presence of iron, and a white precipitate that of zinc. Estimation: A quantitative estimation of the purity of potassium iodide may be made by dissolving 1 gram of the salt in 10 grams of ammonia-water, and adding to the solution a solution of not less than 1.1 grams of argentic nitrate in 20 grams of water ; the mix- ture is then well agitated, filtered, and the precipitate of argentic iodide well washed with water, and finally dried at 100° C. (212° F.) until of constant weight. If the potassium iodide was pure, 1.415 grams of argentic iodide should be obtained, or, 100 parts of argentic iodide correspond to 70.65 parts of potassium iodide. The estimation of the purity of potassium iodide may also be accomplished volumetrically by the following method : This is based upoh the fact that mercuric chloride precipitates from a solution of potassium iodide, red mercuric iodide, which is soluble in an excess of a solution of potassium iodide with the formation of a soluble double salt, and the solution of the latter again yields 494 MANUAL OF CHEMICAL ANALYSIS. upon the subsequent addition of mercuric chloride a precipitate of mercuric iodide. 2KI + HgCl2 = Hgl2 + 2KC1 Hgl2 + 2KI = HgK2I4 4KI + IIgCl2 = HgK2I4 + 2KC1. or 664 (5) 271 (2.03) 2.03 grams of mercuric chloride are dissolved in water to the measure of 100 cubic centimeters, and 5 grams of the potassium iodide under examination are likewise dissolved in water to the measure of 100 cubic centimeters;* 10 cubic centimeters of the po- tassium iodide solution are then brought into a beaker, which is placed upon a sheet of white paper, and the above solution of mer- curic chloride allowed to flow into the liquid from a burette until, with constant stirring, a permanent precipitate of mercuric iodide is just produced. The number of cubic centimeters of the mer- curic chloride solution which are required to produce this reac- tion, when multiplied by 10, will represent the percentage amount of pure potassium iodide contained in the salt. The accuracy of the result of the estimation by the above method is not influenced by the presence of chloride or of considerable amounts of bromide. POTASSII NITRAS. POTASSIUM SEU KALIUM NITRICUM. Nitrate of Potassium. Saltpetre. Nitre. Potassium Nitrate. Ger. Salpetersaures Kalium, Salpeter ; Fr. Azotate de potasse ; Sp. Nitrato de potasa. KNOs; 101. Long, striated, six-sided, prismatic crystals, belonging to the rhombic system (Fig. 150), colorless and transparent, and of a spec. grav. of 2.0; or a white, granular powder, permanent in the air. It melts at about 340° C. (642.2° F.) without decomposition, and solidifies on cooling to a white, opaque, crystalline mass; at a red heat, it is decomposed with the evolution of oxygen and nitrogen gases, and leaving a residue consisting principally of po- tassium nitrate, oxide, and dioxide, which emits nitrous vapors on the addition of sulphuric acid. When thrown upon burning coals, * The results attained by this method are rendered more accurate when, in- stead of dissolving the mercuric chloride and potassium iodide in water, alcohol 17 5 100 of 17.5 per cent, by volume is employed. From the formula x = '—' in n which n represents the percentage strength of the alcohol to be diluted, the vol- ume of alcohol maybe calculated which must be added to the water in order to obtain 100 parts of alcohol of 17.5 per cent, by volume. POTASSIUM. 495 it deflagrates with bright scintillations, leaving an alkaline resi- due, which, when heated upon the looped end of a platinum-wire, imparts a violet color to the non-luminous flame. Potassium nitrate is soluble in 3.8 parts of water at 15° C. (59° F.), and in 0.4 part of boiling water; it is far less soluble in glycerin, and almost insolu- ble in alcohol; its aqueous solution is neutral, has a cooling, saline taste, and forms a white, granular precipitate with a concentrated solution of sodium bitartrate; a few drops of it mixed with a solution of ferrous sulphate, and carefully placed upon con- centrated sulphuric acid (Fig. 146, page 476), give rise to the formation of a dark coloration upon the line of contact between the two fluids. Examination: Chloride and sulphate are detected in the diluted solution of the salt, acidulated with nitric acid, by ensuing white precipitates when tested in two separate portions, with argentic nitrate for chloride, and with barium nitrate for sulphate. Chlorate is indicated bv a yellow coloration, and the evolution of chlorine, when a concentrated solution of the potassium nitrate is mixed and gently'warmed with an equal volume of concentrated hydrochloric acid. Calcium and magnesium salts are detected by a white turbidity when the diluted solution is warmed with dilute solution of sodium carbonate; they may be distinguished by adding a little ammo- nium chloride and ammonia-water to the dilute solution of the salt, and testing it, in separate portions, with ammonium oxalate for calcium, and, after filtration, if necessary, with sodium phos- phate for magnesium. Potassium nitrite may be detected by a violet or blue colora- tion, when to a solution of the salt a little mucilage of starch, a few drops of a solution of pure potassium iodide, and subsequently dilute sulphuric acid are added. Sodium salts will be indicated by their property of imparting a persistent yellow color to the non-luminous flame, as also by a white, crystalline precipitate, occurring either at once or after several hours, when a concentrated cold solution of the salt is tested with a few drops of solution of potassium antimoniate. When thus indicated, the extent of such a contamination may be determined by repeatedly extracting a weighed amount of the powdered salt with boiling alcohol of the spec. grav. 0.890; the filtered liquid will then leave, upon evaporation, a residue, con- sisting principally of sodium nitrate with a little potassium nitrate. The residue is then dissolved in a little wrater, acidulated with hydrochloric acid, and the potassium completely precipitated by the addition of platinic chloride and a little alcohol; the liquid is subsequently filtered from the precipitate of potassio-platinic Fig. 150. 496 MANUAL OF CHEMICAL ANALYSIS. chloride, the excess of platinum removed bv saturation with hydrogen sulphide, and, after filtration, evaporated to dryness, ignited at a gentle heat, and the residue finally weighed as sodium chloride: 100 parts of which correspond to 145.3 parts of sodium nitrate. If potassium nitrate contains even a few per cent, of sodium nitrate, it will have a moist appearance, arising from the deli- quescent character of the latter salt. Metallic impurities will be indicated by a dark coloration or precipitate, when a solution of the salt, acidulated with hydro- chloric acid, is tested with hydrogen sulphide, and, after filtration, if necessary, and neutralization with ammonia-water, by the sub- sequent addition of ammonium sulphide. Estimation: The proper amount of nitric acid contained in the salt may be conveniently determined by its ignition in a small porcelain cru- cible, at a red heat, with an equal weight of concentrated sulphuric acid, until it ceases to lose weight. One gram of the salt, if per- fectly pure, will thus afford a residue of potassium sulphate, weighing 0.86 gram. The determination of the proper amount of potassium in the salt, when free from sodium, may also readily be accomplished, as follows. A weighed amount (about 5 gram's) of the potassium nitrate, contained in a porcelain capsule, is repeatedly evaporated with a solution of about 8 grams of oxalic acid to dryness, or until completely converted into potassium oxalate. The latter is then, by ignition, converted into potassium carbonate, which is dissolved in water, and, after the addition of a few drops of litmus solution, titrated with a standard solution of oxalic or sulphuric acid (page 82), as described under potassium carbonate, on page 474. The calculation may then be made with the consideration that one cubic centimeter of normal ac’d corresponds to 0.069 gram of potassium carbonate, or, as its equivalent, 0.101 gram of pure potassium nitrate. Table of the 'percentage strength of solutions of Potassium Nitrate of different specific gravities. Temperature 15° C. (59° F.) Per cent, of KN03. Specific gravity. Per cent, of KN08. Specific gravity. Per cent, of KN03 Specific gravity. 1 1.00641 8 1.05197 15 1.09977 2 1.01283 9 1.05801 10 1.10701 3 1.01924 10 1.00524 17 1.11420 4 1.02500 11 1.07215 18 1.12150 5 1.03207 12 1.07905 19 1.12875 6 1.08870 13 1.08590 20 1.13599 7 1.04534 14 1.09280 21 1.14301 POTASSIUM. 497 POTASSII PERMANGANAS. POTASSIUM SEU KALIUM PERMANGANICUM SEU HYPERMANGANICUM. Ger. Uebermangansaures Kalium ; Fr. Permanganate de potasse ; Sp. Permanganato de potasa. Permanganate of Potassium. Potassium Permanganate. K2Mn208; 314. Slend er, dark-purple, prismatic crystals, belonging to the rhom- bic system (Fig. 151), of a metallic lustre, permanent in the air, and having a specific gravity of 2.71; they decrepitate when thrown upon burning coals, or when sud- denly heated, and when mixed with sulphur or phosphorus, a mixture is obtained which takes fire or explodes violently on percussion or by heating; on exposure to a red heat, the salt, gives off oxygen, and leaves a black residue of an alkaline reaction. Potassium permanganate is soluble, with the ex- ception of a slight brown residue, in 20 parts of water at 15° C. (59° F.), and in 3 parts of boiling water; it is insoluble in alcohol, and is slowly de- composed in contact therewith. Its concentrated solution has a deep violet-red color, when highly diluted, a rose color, a sweet, astringent taste, is neutral, and becomes yellowish-brown when mixed and heated with alcohol. Since permanganic acid is readily reduced, the solution of the salt is decomposed and decolorized by most organic substances, and by inorganic reducing agents— e. y., sulphurous and oxalic acids, hydrogen sulphide, and all metallic subsalts. Potassium permanganate is, therefore, a pow- erful oxidizer, causing more or less violent reactions with many substances, and the combustion of inflammable bodies. Examination: The purity of the salt may readily be determined by the fol- lowing simple test: 0.314 gram of the potassium permanganate is dissolved in water to the measure of one liter; another solution is then prepared by dissolving 0.63 gram of pure, crystallized oxalic acid in water, acidulated with sulphuric acid, to the measure of a liter ; if the potassium permanganate is pure, one cubic centi- meter of the above permanganate solution will require for com- plete decoloration an equal volume, or exactly one cubic centimeter of the oxalic acid solution, and the amount of the latter, which is required to produce this reaction, will be, therefore, in direct pro- portion to the purity of the salt. Fig. 151. 498 MANUAL OF CHEMICAL ANALYSIS. Nitrate and Chloride.—A portion of the decolorized liquid, as obtained by the preceding test, is carefully poured upon a cold solution of ferrous sulphate in strong sulphuric acid, when a dark- colored zone at the line of contact of the two liquids will indicate the presence of nitrate : another portion of the decolorized liquid is tested with a few drops of a solution of argentic chloride, when a permanent white turb:dity or precipitate will reveal the presence of chloride. Sxdphate may be detected by boiling an aqueous solution of the salt with an excess of ammonia-water, until all the manganese is precipitated as hydrated oxide; the liquid is then filtered, and the colorless filtrate subsequently tested with barium chloride, when an ensuing white precipitate will reveal the presence of sulphate. The United States Pharmacopoeia directs that if 0.785 gram of the salt be dissolved in 50 cubic centimeters of boiling, distilled water, and 5 cubic centimeters of sulphuric acid be cautiously added, the solution so formed should require for complete decolora- tion not less than 24.7 cubic centimeters of the volumetric solu- tion of oxalic acid (corresponding to at least 98.8 per cent, of pure potassium permanganate). POTASSII SULPHAS. POTASSIUM SEU KALIUM SULFURICUM. Sulphate of Potassium. Potassium Sulphate. Ger. Scliwefelsaures Kalium ; Fr. Sulfate de potasse ; Sp. Sulfato de potasa. K2S04; 174. Hard, colorless, transparent, short, six-sided prisms, or pyra- mids, belonging to the rhombic system (Fig. 152), or a white, granular powder, anhydrous, and permanent in the air, and having a spec. grav. of 2.648; when heated, the crystals decrepitate strongly, and at a strong, red heat they fuse, without de- composition, solidifying again on cooling to a crystalline mass; at a white heat, they are to a slight extent volatilized. The salt, when heated on the looped end of a platinum-wire, imparts a violet color to the non-luminous flame. Potassium sulphate is soluble in 9 parts of water at 15° C. (59° F.), in 4 parts of boiling water, sparingly soluble in glycerin, and in- soluble in strong alcohol, and solution of potas- sium hydrate of the spec. grav. 1.35. Its aqueous solution has a saline bitter taste, is neutral, and forms white precipitates with Fig. 152. 499 POTASSIUM. tartaric acid or sodium bitartrate, and with solutions of salts of calcium, barium, or lead. Examination: Potassium bisulphate will be indicated by an acid reaction of the solution of the salt, and also by the loss of weight, when the salt, previously dried at 110° C. (230° F.), is heated nearly to redness in a covered porcelain crucible. Sodium sulphate is indicated by the property of imparting a persistent yellow color to the non-luminous flame, and by a greater degree of solubility in cold water than that above stated; one part of the powdered salt, when dissolved in eight parts of boil- ing water, must, on cooling, give a crystalline deposit; otherwise sodium sulphate, or an admixture of more soluble salts, is indi- cated ; in this case the solution may be tested with potassium metantimoniate for sodium, and, in another portion, after dilution with water and acidulation with nitric acid, by means of argentic nitrate for chloride. Nitrate will be detected in the aqueous solu- tion of the salt, after the addition of a drop of indigo solution and a little concentrated sulphuric acid, by decoloration of the liquid upon heating. Calcium and Magnesium Salts.— The aqueous solution of the salt is tested with ammonium oxalate, when a white precipitate will reveal the presence of calcium; after the removal of the latter, if present, by filtration, solution of ammonium chloride, ammonia-water, and sodium phosphate are added, when the forma- tion of a white, crystalline precipitate will reveal the presence of magnesium. Metallic impurities are detected in the warm aqueous solution, after acidulation with hydrochloric acid, by a dark coloration or turbidity upon saturation with hydrogen sulphide, or, after filtra- tion, if necessary, and neutralization with ammonia-water, by the addition of ammonium sulphide. Potassium ferrocyanide should cause neither a blue {iron) nor a reddish {copper) coloration in the slightly acidulated solution. POTASSII SULPHIS. POTASSIUM SEU KALIUM SULFUROSUM. Sulphite of Potassium. Potassium Sulphite. Ger. Scliwefligsaures Kalium ; Fr. Sulfite de potasse ; Sp. Sulfito de potasa. K S03 + 2H20; 194. Colorless, opaque, obliquely rhombic, octohedral crystals, or a white, crystalline powder, odorless, and somewhat deliquescent on exposure to a moist atmosphere ; it contains two molecules (18.55 MANUAL OF CHEMICAL ANALYSIS. per cent.) of water of crystallization, which are lost by drying at a moderate heat; at a red heat it is decomposed, leaving an alka- 1 ne residue consisting of potassium sulphate, sulphide, and oxide, which imparts a brown color to moistened turmeric paper, and, on the addition of an acid, develops the odor of hydrogen sul- phide. Potassium sulphite is soluble in 4 parts of water at 15° C. (59° F,), and in 5 parts of boiling water, but is very sparingly soluble in alcohol. The aqueous solution 'possesses a bitter, saline, and sulphurous taste, a slightly alkaline reaction, and yields a white crystalline precipitate on the addition of a concentrated solution of sodium bitartrate; with argentic nitrate it yields a white precipitate, which becomes blackened on heating. On the addition of dilute hydrochloric or sulphuric acid to the solution of the salt, sulphur dioxide is liberated, which may be recognized by the odor of burning sulphur, but no turbidity is thereby pro- duced in the liquid (distinction from hyposulphite). Examination: Sulphate may be detected in the dilute solution of the salt, strongly acidulated with hydrochloric acid, by a white precipitate on the addition of barium chloride. Estimation: About 0.3 gram of the salt is dissolved in 25 cubic centimeters of water, in a beaker, a little mucilage of starch added, and sub- sequently a deeinormal solution of iodine (page 93) allowed to flow into the liquid from a burette until, with constant stirring, a permanent blue coloration of the liquid is just produced. The number of cubic centimeters of iodine solution required to pro- duce this reaction, when multiplied by the decimal 0.0097, will represent the amount of pure, crystallized potassium sulphite, K2S03-f 2H20, in the quantity employed, and therefrom its per- centage purity may readily be calculated. The United States Pharmacopoeia directs that if 0.485 gram of the salt be dissolved in 25 cubic centimeters of water, and a little gelatinized starch added, at least 45 cubic centimeters of the volumetric solution of iod ne should be required, until a per- manent blue tint appears after stirring (corresponding to at least 90 per cent, of pure potassium sulphite). POTASSIUM. 501 POTASSII TARTRAS. POTASSIUM SEU KALIUM TARTARICUM. Tartrate of Potassium. Potassium Tartrate. Ger. Weinsaures Kalium ; Fr. Tartrate de potasse ; Sp. Tartrato de potasa. CI!(OH)-CO-OK CH(OH)-CO-OK k2c4h4o6+JH2o = + |H20; 235. Colorless, semi-transparent, irregular, six-sided prisms, with dihedral summits, belonging to the monoclinie system, or a white, granular powder, of the specific gravity 1.96, and slightly deli- quescent on exposure to a moist atmosphere. The salt contains one-half molecule (3.83 per cent.) of water of crystallization ; when moderately heated, it melts, and, at a higher temperature, becomes charred and decomposed, with the evolution of empy- reumatic vapors having the odor of burnt sugar; when strongly ignited at a red heat, it leaves a blackened alkaline residue, con- sisting of a mixture of carbon and potassium carbonate, which effervesces with acids, and imparts a violet color to the non-lumi- nous flame. Potassium tartrate is soluble in 0.7 part of water at 15° C. (59° F.), and in 0.5 part of boiling water, yielding a neutral solution, of a mild saline taste; it is but sparingly soluble in alcohol; its aqueous solution is decomposed by most acids and acidulous salts, forming, if not too dilute, a white, granular deposit of bitartrate, and yields with argentic nitrate a white precipitate, which be- comes blackened on heating; the concentrated solution, also pro- duces with calcium, barium, and lead salts, white precipitates, which are soluble in dilute nitric acid. Examination: Potassium and Sodium Tartrate.—One part of the salt when shaken with an equal weight of water must afford a clear and complete solution; an incomplete solution may ind cate an ad- mixture of Rochelle salt. Such an admixture will also be indi- cated by a greater loss of weight on drying the salt at 100° C. (212° F.), pure Rochelle salt losing at this temperature 19.1 per cent, of its weight; and may be further ascertained by reducing a portion of the potassium tartrate, by ignition in a porcelain crucible, to carbonate, and then testing the res due in the non- lu minous flame, when a persistent bright-yellow color will reveal the presence of sodium; the filtered solution of the residue may afterwards be tested by mixing it with an equal volume of solu- tion of potassium metantimoniate; the occurrence of a white, crystalline deposit, at once or after several hours’ standing, would indicate an adulteration with potassium and sodium tartrate. Bicarbonate, carbonate, and bitartrate are recognized in the solu- 502 MANUAL OF CHEMICAL ANALYSTS. tion of the salt, the two former by effervescence on the addition of an acid, and by an alkaline reaction upon turmeric-paper; the latter by its relatively sparing solubility in cold water, and by an acid reaction upon blue litmus-paper. Ammonium salts will be recognized by the development of the odor of ammonia, when a portion of the salt is heated, in a test- tube, with a strong solution of potassium or sodium hydrate, and by the development of white fumes, when a glass rod, moistened with acetic acid, is held over the mouth of the tube. Calcium salts will be indicated in the solution by a white pre- cipitate on the addition of solution of ammonium oxalate. Sulphate and chloride may be detected in the dilute solution of the salt, when it is slightly acidulated with diluted nitric acid, and then tested, in separate portions, with argentic nitrate for chloride, and with barium nitrate for sulphate. Metallic imparities are recognized in the concentrated solution of the salt, after acidulation with hydrochloric acid and subse- quent filtration, by a dark coloration or turbidity upon saturation with hydrogen sulphide; or, after filtration, if necessary, by sub- sequent neutralization with ammonia-water, and the addition of ammonium sulphide. Estimation: 2.938 grams of the salt are ignited in a porcelain crucible, at a red heat, until gases cease to be evolved; the alkaline residue is then extracted with warm water, the solution filtered into a beaker, a few drops of litmus solution added, and titrated, with the aid of a gentle heat, with a standard solution of oxalic or sul- phuric acid (page 82), as described under potassium carbonate, on page 474. The number of cubic centimeters of normal.acid solution which is thus required for the exact neutralization of the liquid, when multiplied by 4, will indicate, without further calculation, the percentage purity of the salt. By the employ- ment of other quantities of the salt than precisely that above stated, the calculation may also readily be made, with the consid- eration that one cubic centimeter of the normal acid solution cor- responds to 0.117 gram of pure crystallized potassium tartrate. QUINIDINA. CHINIDINUM SEU CONCHININUM. Quinidine, Quinidia, or Gonquinia. Ger. Chinidin (Conchinin) ; Fr. Quinidine ; Sp. Quinidiua. Large, colorless, shining, four-sided prisms, containing 2 mole- cules (10 per cent.) of water of crystallization, and possessing a 0„H„NJOt+2H,0; 360. QUINIDINA. 503 very bitter taste and a slightly alkaline reaction ; when heated to 120° C. (248° F.), they lose their water of crystallization, and, when thus deprived of water, melt at 168° C. (334.4° F.), to a colorless liquid, which solidifies in a crystalline form upon cool- ing; at a higher temperature they are decomposed, and when strongly heated on platinum-foil, burn slowly away, leaving no residue. Quinidine is soluble in 2000 parts of water at 15° C. (59° F.), and in 750 parts of boiling water, in 26 parts of alcohol, and 22 parts of ether at 20° C. (68° F.), and is also soluble in chloroform, carbon bisulphide, and benzol; it is freely soluble in water acidu- lated with sulphuric acid, and the solution displays a blue fluorescence. It neutralizes the acids, with the formation of neutral and acid salts, which are mostly well crystallizable. When exactly neutralized with diluted sulphuric acid, quinidine yields a solution which affords the same reactions as quinidine sulphate, and should respond to the tests for quality and purity, as described under the latter, on pages 503-504. QUINIDINiB SULPHAS. CHINIDINUM SEU CONCHININUM SULFURICUM. Sulphate of Quinidine, Quinidia, or Gonquinia. Quinidine Sulphate. Ger. Schwefelsaures Cliiniclin ; Fr. Sulfate de quinidine ; Sp. Sulfato de quinidina. (0»HMN,0,)aHaS04 + 2Ha0; 782. White, silky, prismatic needles or tufts, permanent in the air, and containing two molecules (4.6 per cent.) of water of crystalli- zation, which are completely eliminated at 120° C. (248° F.); when strongly heated, they burn slowly away, leaving no residue. Quinidine sulphate is soluble in 100 parts of water, and in 8 parts of alcohol at 15° C. (59° F.); in 7 parts of boiling water, and very soluble in boiling alcohol; it is freely soluble in acidu- lated water, and in 20 parts of chloroform at 15° C. (59° F.), but is almost insoluble in ether. The aqueous solution is neutral in its action upon litmus, possesses an intensely bitter taste, and, when acidulated with sulphuric acid, displays a blue fluorescence; with barium chloride it yields a white precipitate, insoluble in hydrochloric or nitric acid, and with chlorine water, followed by the addition of ammonia-water in slight excess, an emerald-green coloration is produced ; if the addition of ammonia-water be pre- ceded by a few drops of a solution of potassium ferrocyanide, the solution assumes a bright-red color. When to a solution of qui- nidine sulphate ammonia-water is added, a white precipitate of 504 MANUAL OF CHEMICAL ANALYSIS. quinidine is produced, which is soluble in a considerable excess of the reagent, and in about thirty times its weight of ether. The neutral aqueous solution of quinidine sulphate yields upon the addition of a concentrated solution of potassium iodide a white granular precipitate of quinidine hydriodate, 020H24N2O2.III, which is very sparingly soluble in water and in alcohol. Examination: Quinine, Cinchonine, and Cinchonidine.—These associate alka- loids of quinidine may readily be detected by the following sim- ple test: 0.5 gram of the quinidine sulphate, together with an equal weight of neutral potassium iodide, is agitated with 10 cubic centimeters of water at about 60° C. (140° F.), the mixture allowed to cool, and stand for an hour, with frequent agitation, and filtered; to the filtrate one or two drops of ammonia-water are then added, when not more than a slight turbidity should be produced; a decided precipitate would reveal the presence of an undue proportion of the above-mentioned associate alkaloids. In consequence of the previously existing confusion in the ap- plication of names, quinidine sulphate is liable to be confounded with the less valuable alkaloid cinchonidine. The admixture or substitution of the latter should therefore be the subject of a special test. It may be detected bv its sparing solubility in chloroform, whereas quinidine sulphate is freely soluble in this liquid, and also by the following test: 0.5 gram of the salt is agitated for about half a minute with 50 cubic centimeters of water at 15° C. (59° F.), and immediately filtered; to the filtrate two or three cubic centimeters of a saturated solution of potas- sium and sodium tartrate (Iiochelle salt) are added, when, if any considerable proportion of cinchonidine be present, a white, gran- ular precipitate of cinchonidine tartrate, (CigII22N20)2C4IIK06, will gradually be formed. Foreign Alkaloids or Neutral Principles.—An accidental admix- ture or substitution of foreign alkaloids, such as morphine, bru- cine, etc., or of neutral principles, such as salicin, may in most instances be detected by a coloration with concentrated sulphuric or nitric acid, whereas pure quinidine sulphate dissolves without color, or with the production of but a faint yellowish tint. Inorganic impurities may be detected by a non-volatile residue when a little of the salt is ignited upon platinum-foil; or by an insoluble residue, when 0.5 gram of the salt is dissolved in a mixture of 8 cubic centimeters of chloroform and 2 cubic centi- meters of absolute alcohol. QUININA. 505 QUININA. CHININUM. CHINIUM. Quinine. Quinia. Ger. Cliinin; Fr. Quinine ; Sp. Quinina. C20H2„N2O2 + 3H2O; 378. A snow-white, flaky, indistinctly crystalline powder, or minute, needle-like crystals, containing 3 molecules (14.28 per cent.) of water of crystallization, efflorescent on exposure to the air, and possessing an alkaline reaction. It melts at 57° C. (134.6° F.), and on the water-bath retains about 5.25 per cent, (about 1 mole- cule) of water of crystallization, which is completely expelled at 125° C. (257° F.); the anhydrous alkaloid then melts at 177° C. (350.6° F.), dissolves in hot water without previously fusing, and, on cooling, separates in needles; while the alkalo.d, containing water of crystallization, first fuses in boiling water, and, on cool- ing, does not crystallize. When strongly heated on platinum- foil, it becomes charred and decomposed, and is finally completely dissipated. Quinine is soluble in about 1600 parts of water at 15° C. (59° F.), in 700 parts of boiling water, in 6 parts of cold, or 2 parts of boiling, alcohol, in 22.7 parts of ether,* in about 5 parts of chloroform, and in 200 parts of glycerin ; and is also soluble in carbon bisulphide, benzol, benzin, and ammonia-water; its solutions have a bitter taste, and a feebly alkaline reaction, and neutralize acids, with the formation of crystallizable salts. Qui- nine is freely soluble in diluted acids, forming solutions which exhibit an azure-blue fluorescence, caused by a change of re- frangibility of the invisible chemical rays ; this property is not displayed, however, by its solution in hydrochloric, hydriodic, or hydrobromic acids, and does not appear in such solutions by the subsequent addition of sulphuric acid ; the fluorescence may like- wise be made to disappear in solutions in which it has previously been produced, by the addition of the above-named acids, as also by solutions of chlorides, bromides, and iodides, with the excep- tion of mercuric chloride and bromide. Concentrated sulphuric and nitric acids dissolve quinine without color, or with the pro- duction of but a slight yellowish tint. Solutions of quinine and its salts are precipitated by the alka- line hydrates, carbonates, and bicarbonates, by calcium hydrate, * The solubility of quinine in ether differs according to the form of the alka- loid : requiring less when in the anhydrous or amorphous condition, as when freshly precipitated from its solution in acidulated water by ammonia-water, and directly shaken with ether, than in the crystalline or hydrated form, which it assumes when the precipitate is allowed to stand for several hours, previous to the addition of the ether. 506 MANUAL OF CHEMICAL ANALYSIS. by tannic and picric acids, by potassium ferrocyanide, potassio- mercuric iodide, iodinized potassium iodide, and most alkaloidal reagents; the precipitates with calcium, potassium, and sodium hydrates, and ammonia-water, are redissolved by a large excess of the precipitant. Solutions of quinine and its salts, when mixed with chlorine- water, and afterwards with an excess of water of ammonia, assume a bright emerald-green color (thalleiochin); the green color passes into red upon the subsequent addition of potassium ferrocyanide; this characteristic reaction is most strikingly exhibited when, to the solution of quinine in chlorine-water, the solution of potassium ferrocjmnide is first added, and subsequently the ammonia-water. When a solution of quinine or its salts in acidulated water is precipitated with ammonia-water, and. the turbid mixture is then divided into three portions in as many test-tubes, and these shaken severally with a little ether, chloroform, and benzol, the precipi- tate will be dissolved, and the liquids subside into two clear, col- orless strata in each test-tube. Examination: The identity of quinine may be conclusively established by the above described physical characters, and its behavior towards re- agents and solvents ; it is also distinguished from many other alka- loids and crystallizable neutral principles, by affording no special coloration in contact with cold concentrated sulphuric or nitric acid. Quinidine, Cinchonine, and Oinchonidine.—1 gram of the quinine is triturated in a mortar with 0.5 gram of ammonium sulphate and 5 cubic centimeters of distilled water, and the mixture thor- oughly dried on the water-bath ; the residue (which should be neutral to test-paper) is agitated with 10 cubic centimeters of dis- tilled water, this mixture macerated at 15° C. (59° F.) for half an hour, then filtered, and to 5 cubic centimeters of the filtrate, in a test-tube, 7 cubic centimeters of ammonia-water, spec. grav. 0.960, are added, without shaking ; on gently turning the test-tube, there should be formed, either at once, or after a short time, a clear liquid ; an ensuing permanent precipitate would indicate an admixture of more than about 1 per cent, of cinchonidine and quinidine, and of more than traces of cinchonine. If the temperature during mace- ration was 16° C. (60.8° F.), 7.5 cubic centimeters of ammonia- water may be added, and if 17° C. (62.6° F.), 8 cubic centimeters may be employed. Inorganic imgmrities may readily be detected by a non-volatile residue, when a small portion of the quinine is strongly heated on platinum-foil. When dissolved in dilute sulphuric acid, quinine should respond to the tests of purity for quinine sulphate, as described under the latter, on pages 521-523. QUININA. 507 Estimation of the Alkaloids in Cinchona-Barks: The therapeutical value of the cinchona-barks is due to the alka- loids contained in the bark, of which the principal ones are qui- nine, quint dine, cinchonine, and cinchonidine. The estimation of the commercial value, therefore, depends upon the determination of the quantity of these alkaloids, and in particular of the first one, in a known weight of the bark. Of the numerous methods employed for this purpose, the following ones are simple, expe- ditious, and reliable: I. Fliickiger’s Process: From a large number of pieces of the bark, small fragments are cut and reduced to a fine powder, so as to represent as nearly as possible an average specimen of the bark to be examined; 20 grams of the powder, contained in a porcelain capsule, are moist- ened with ammonia-water, and, after standing for an hour, mixed with 80 grams of hot water ; it is then allowed to cool, subsequently intimately mixed with milkof lime(prepared bv triturating 5grams of dry caustic lime with 50 grams of water), and the mixture evapo- rated upon the water-bath until it is uniformly converted into small, somewhat moist, crumb-like particles. This is then transferred to a cylindrical glass tube (Fig. 153), which at A is 2.5 centimeters (1 inch) wide, and from A to B 16 centimeters (6.4 inches) long. At B a small brass sieve is inserted, upon which a disk of filtering paper is secured by means of a bunch of loose cotton. The powder having been quite com- pactly adjusted upon the cotton, it is again covered at A, as in B, with a little cotton; the latter having been previously employed for removing the last traces of the powdered bark from the capsule. At K a tightly fitting cork is inserted, which is pene- trated by the tube R, and connected with an inverted small glass condenser. The lower end of the appa- ratus, C\ is tightly connected by means of a cork with the flask K, containing about 100 cubic centi- meters of ether. The flask is then heated by means of a constant water-bath ; and in the same degree as the vapors of ether are expelled through D, they become again condensed in the condenser, drop through the tube R upon the powder at A, penetrate the entire column of powder A B, and flow at C, saturated with alkaloid, into the flask K. To effect the complete exhaustion of the bark by the ether, the operation of displacement should be continued for nearly a dav, but when once in progress it requires but little attention. In order to determine whether the bark is completely exhausted, a few drops of the ether, falling at C, are collected in a small test-tube, and tested with potassio-mercuric Fig.153. 508 MANUAL OF CHEMICAL ANALYSIS. iodide; which should afford no turbidity if the process of extrac- tion has been sufficiently long continued. When this is accom- plished, 36 cubic centimeters of one-tenth normal hydrochloric acid (3.65 grams HC1 in 1 liter) are added to the ether in the flask W, the ether distilled off, and subsequently so much hydrochloric acid added as may be required to impart to the liquid an acid reaction. The liquid is then filtered from the separated mixture of fat, chinovin, and chlorophyll, and, after having become thoroughly cooled, 40 cubic centimeters of one-tenth normal sodium hydrate solution (4 grams NaOII in 1 liter) are added, and the whole allowed to repose until the precipitate has sub- sided, and the supernatant liquid has become perfectly clear. Sodium hydrate is then gradually added to the liquid as long as a precipitate continues to be produced, for which purpose a solution of the spec. grav. 1.3 is the most serviceable. The precipitated -alkaloids are afterwards collected on a filter, and gradually washed with a little cold water until a few drops of the washings, when allowed to flow on the surface of a cold, saturated, neutral, aqueous solution of quinine sulphate, cease to produce a turbidity. The drained precipitate, contained on the filter, is then gently pressed between bibulous paper, and dried by exposure to the air; it may afterwards readily be removed from the paper without loss, and, after thoroughly drying upon a watch-glass over sulphuric acid, is finally dried at 100° C. (212° F.), and weighed ; the weight of the precipitate, multiplied by 5, will give the total percentage of mixed alkaloids in the bark. If it be de- sired to establish the* presence of quinine in the precipitate, a small portion of it may be dissolved in acidulated water, and sub- sequently tested with chlorine-water and ammonia, as described on page 506. Separation of the Alkaloids. When the separation and quantitative estimation of the re- spective alkaloids are required, the following method of De Vrij may be employed. The powdered mixed alkaloids are treated with ten times their weight of ether, and, after agitation, left at rest till the next day. By this operation the alkaloids are sepa- rated into two parts, viz., one (A) soluble in ether, and another (B) insoluble in that liquid. The part soluble in ether contains the quinine and the amorphous alkaloid, together with traces of quinidine, while the insoluble part contains the cinchonine, cin- chonidine, and quinidine. These two parts are separated by filtration, the insoluble portion washed with a little ether, and the ethereal solution either directly evaporated, or the ether recov- ered by distillation. A. Part Soluble in Ether.—The ether having been evaporated, and the residue dried at 100° C. (212° F.), this may in many QUININA. 509 cases be practically considered as consisting simply of quinine. If, however, the estimation of the quinidine and amorphous alka- loid is required, the residue is dissolved in sufficient acetic acid to afford a neutral solution, and an alcoholic solution of potassium iodide added, which will produce a sandy precipitate of quinidine hydriodate,* C20H24N2O2.FII. One part of this hydriodate, when dried at 100° C. (212° F.), represents 0.717 part of anhydrous qui- nidine. To the warmed filtrate from the latter precipitate ammo- nia-water is added until it ceases to produce a precipitate; the mixture is then shaken at once with ether, the ethereal solution allowed to evaporate, and the residue dried at 100° C. (212° F.). This residue will consist principally of quinine, accompanied pos- sibly by amorphous alkaloid and quinamine. In order to exclude the latter bases, which are always only present in very small amount, the ethereal residue is dissolved in 10 parts of diluted alcohol, spec. grav. 0.915, the solution exactly neutralized with alcoholic sulphuric acid, and as much of the latter afterwards added as was required for neutralization. To this solution an alcoholic solution of iodine is carefully added until a precipitate ceases to be formed. If a considerable amount of quinine is present, there will appear immediately a black precipitate of quinine iodo-sulphate or herapathite, but if the amount of quinine is only very small, it may happen that no precipitate will be formed at once, and in the latter case only a small amount of iodine should be added, and the liquid, after having been well stirred with a glass rod, is left at rest till the next day. If qui- nine is really present, it will then be precipitated in the form of herapathite, which may be collected on a filter, washed with strong alcohol, and first dried upon bibulous paper and afterwards at 100° C. (212° F.). One part of the herapathite, when thus dried, represents, in accordance with the formula (C20H24N2O2)4-f- 3H2S04 4- 2III+ 41, 0.55 part of pure quinine. To the liquid separated from the herapathite, a few drops of sulphurous acid are added, whereby the iodo-sulphate of amor- phous alkaloid is converted into hydriodate, and the reddish- brown color of the solution disappears. The solution is then carefully neutralized with sodium hydrate, heated on the water- bath to expel the alcohol, and a solut on of sodium hydrate in slight excess subsequently added, by which the amorphous alka- loid will be precipitated, including quinamine if present. B. Part Insoluble in Ether.—This is converted into neutral acetate by the addition of a sufficient quantity of acetic acid, and to the solution potassium and sodium tartrate (Kochelle salt) in slight excess is subsequently added. After stirring with a glass * If only traces of quinidine be present, as is usually the case, no precipitate will be formed; but simply white striae on the surfaces of the glass which have come in contact with the glass rod. 510 MANUAL OF CHEMICAL ANALYSIS. rod, the solution is left at rest for a day, when, if cinchonidine is present in appreciable quantity, its tartrate will be separated in a crystalline form, while the other tartrates remain dissolved. The cinchonidine tartrate is collected on a filter, washed with a little cold water, and, after first drying upon bibulous paper, is finally dried at 100° C. (212° F.), and weighed. One part of cin- chonidine tartrate represents, in accordance with the formula (C,0II22N20)2.C4Hb06, 0.796 part of pure cinchonidine. To the filtrate from the latter precipitate, a solution of potas- sium iodide is added, and the whole well stirred with a glass rod. The quinidine will thus be precipitated as hydriodate, in the form of a sandy crystalline powder; it is collected on a filter, washed with a little cold water, and, after first drying on bibulous paper, is finally dried at 100° O. (212° F.), and weighed. One part of this hydriodate represents 0.717 part of pure anhydrous quinidine. The filtrate from the quinidine hydriodate is finally precipitated with sodium hydrate, whereby the cinchonine is obtained; this is collected on a filter, washed with a little cold water, and, after first drying between bibulous paper, is finally dried at 100° C. (212° F.), and weighed. II. Squibb’s Process: To 1.25 grams (19.29 grains) of well-burnt lime, contained in a 10-centimeter (4-inch) capsule, 30 cubic centimeters (1 fluidounce) of hot water are added, and, when the lime is slaked, the mixture is stirred, and 5 grams (77.16 grains) of the powdered cinchona are added, the mixture very thoroughly stirred, and digested in a warm place for a few hours, or over night. The mixture is then dried at a low temperature on a water-bath, rubbed to powder in the capsule, and transferred to a flask of 100 cubic centimeters (3.3 fluidounces) capacity, and 25 cubic centimeters (0.8 fluidounce) of amylic alcohol added. The flask is afterward corked, and digested in a water-bath at a boiling temperature and with fre- quent, vigorous shaking for four hours. It is then allowed to cool, and 60 cubic centimeters (2 fluidounces) of stronger ether, spec. grav. 0.728, added, and again shaken vigorously and fre- quently during an hour or more. The liquid is now filtered through a double filter of 10 centimeters (4 inches) diameter into a flask of 150 cubic centimeters (5 fluidounces) capacity, and the residue transferred to the filter. The flask is rinsed and the rinsings brought on to the filter with a mixture of 10 volumes of amylic alcohol and 40 volumes of stronger ether, and the residue on the filter percolated with 15 cubic centimeters f0.5 fluidounce) of the same mixture, added drop by drop from a pipette to the edges of the filter and surface of the residue. The residue is afterward returned to the flask from whence it came, 30 cubic centimeters (1 fluidounce) of the amylic alcohol and ether mix- ture added, shaken vigorously for five minutes or more, and the QUININA. 511 whole returned to the filter, and the residue again percolated with 15 cubic centimeters of the menstruum, applied drop by drop from a pipette, as before. The filter and residue are now put aside in order that it may be afterward tested in regard to the degree of exhaustion. The ether is now boiled off from the filtrate in the flask by means of a water-bath, taking great care to avoid the ignition of the ether vapor, and also to avoid explosive boiling, by having a long wire in the flask. When boiled down as far as practicable in the flask, the remainder is transferred to a tared capsule of 10 centimeters (4 inches) diameter, and the evaporation continued on a water-bath until the contents are reduced to about 6 grams (92 grains). This is transferred to a flask of 100 cubic centimeters (3.8 fluidounces) capacity, rinsing the capsule with not more than 4 cubic centimeters (64 minims) of arnylic alcohol, and adding the same to the contents of the flask. 6 cubic centimeters (96 minims) of water and 4 cubic centimeters (64 minims) of normal solution of oxalic acid are then added, and the mixture shaken vigor- ously and frequently during half an hour. The mixture, while intimately well mixed, is poured on to a well-wetted double filter of 12 centimeters (4.75 inches) diameter, and the aqueous solution filtered from the arnylic alcohol into a tared capsule of 10 cen- timeters (4 inches) diameter. The filter and contents are washed with 5 cubic centimeters (80 minims) of water, applied drop by drop from a pipette to the edges of the filter and surface of the ainylic alcohol. The arnylic alcohol is then poured back into the flask over the edge of the filter and funnel, rinsing the last por- tion in with a few drops of water. 10 cubic centimeters (160 minims) of water and 1 cubic centimeter (16 minims) of normal solution of oxalic acid are now added, again shaken vigorously for a minute or two, and the whole returned to the wetted filter, and the aqueous portion filtered off into the capsule with the first portion. The arnylic alcohol is again returned to the flask, and the washings repeated with the same quantities of water and nor- mal oxalic acid solution. When this has drained through, the filter and contents are washed with 5 cubic centimeters (80 minims) of water, applied drop by drop from a pipette. The total filtrate in the capsule is evaporated on a water-bath, at a low tem- perature, until it is reduce'd to about 15 grams (241 grains) and this transferred to a flask of 100 cubic centimeters (3.3 fluidounces) capacity, rinsing the capsule with 5 cubic centimeters (80 minims) of water, and adding this to the contents of the flask. 20 cubic centimeters (0.66 fluidounce) of purified chloroform are now first added, and then 6.1 cubic centimeters (98 minims) of normal solu- tion of sodium hydrate, and shaken vigorously for five minutes or more. While still intimately mixed by the shaking, the mix- ture is poured upon a filter of 12 centimeters (4.75 inches) diam- eter, well wetted with water. When the aqueous solution has 512 MANUAL OF CHEMICAL ANALYSIS. passed through, leaving the chloroform on the filter, the filter and chloroform are washed with 5 cubic centimeters (80 minims) of water, applied drop by drop. The chloroform solution is then, by making a pin-hole in the point of the filter, transferred to another filter of 10 centimeters (4 inches) diameter, well wetted with chloroform, and placed over a tared flask of 100 cubic cen- timeters (3.8 fluidounces) capacity. The watery filter is washed through into the chloroform-wet filter with 5 cubic centimeters (80 minims) of purified chloroform, and, when this has passed through into the flask, the chloroform-wet filter is also washed with 5 cubic centimeters (80 minims) of chloroform, applied drop by drop to the edges of the filter. When the whole chloroform solution of alkaloids is collected in a flask, the chloroform is boiled off' to dryness in a water-bath, when the alkaloids will be left in warty groups of radiating crystals, adhering over the bot- tom and sides of the flask. The flask is then placed on its side in a drying-oven, and dried at 100° C. (212° F.) to a constant weight. The weight of the contents, multiplied by 20, gives the percentage of the total alkaloids of the cinchona in an anhydrous condition, to within 0.1 or 0.2 per cent., if the process has been well managed. Estimation of Quinine, Into the flask containing the total alkaloids, after these have been weighed, are placed 5 grams (78 grains) of glass, which has been ground up in a mortar to a mixture of coarse and tine powder, and 5 cubic centimeters (80 minims) of stronger ether added. The flask is then corked, and shaken vigorously until, by means of the glass, all the alkaloids have been detached from the flask and ground up in the presence of the ether into fine particles. In this way the definite quantity of ether which is large enough to dissolve all the quinine that could possibly be present, becomes entirely saturated with alkaloids in the propor- tion of their solubility, and the solution will necessarily embrace all the very soluble ones as the quinine. Two test-tubes are now marked at the capacity of 10 cubic centimeters (160 minims each), and a funnel and filter of 7 centi- meters (2.8 inches) diameter placed over one of them. The filter is well wetted with ether, and the mixture of alkaloids, ether, and glass poured on to it from the flask. The flask is rinsed out two or three times on to the filter with fresh ether, the filter then washed, and the glass percolated with fresh ether, applied drop by drop from a pipette, until the liquid in the test-tube reaches the 10-cubic-centimeter (160-miniin) mark. The funnel is then changed to the other test-tube, and the washing and percolation with ether continued until the mark on the second test-tube is QUININA. 513 reached by the filtrate. The contents of the two test-tubes are poured into two small tared capsules, evaporated to a constant- weight, and weighed. The first capsule will contain what may be called the ether-soluble alkaloids, and if from the weight of these the weight of the residue in the second capsule be sub- tracted, the remainder will be the approximate weight of the quinine extracted from the 5 grams of bark. These weights, multiplied by 20, will give the percentage of ether-soluble alka- loids and of quinine. III. Process of the United States Pharmacopoeia: 1. For Total Alkaloids. Twenty grams of the cinchona, in very fine powder, and fully dried at 100° C. (212° F.), are thoroughly mixed with 5 grams of lime which has previously been made into a milk with 50 cubic centimeters of distilled water, and the'mixture completely dried at a temperature not above 80° C. (176° F.). The dried mixture is digested with 200 cubic centimeters of alcohol, in a flask, near the temperature of boiling, for one hour, and, when cool, the mixture poured upon a filter of about 15 centimeters (6 inches) diameter. The flask is rinsed and the filter washed with 200 cubic centimeters of alcohol, used in several portions, and allowing the filter to drain after the use of each portion. To the filtered liquid enough diluted sulphuric acid is added to render the liquid acid to test-paper, any resulting precipitate (calcium sulphate) allowed to subside, the liquid decanted, in portions, upon a very small filter, and the residue and filter washed with small portions of alcohol. The filtrate is then distilled or evapo- rated to expel all the alcohol, allowed to cool, passed through a small filter, and the latter washed with distilled water slightly acidulated with diluted sulphuric acid, until the washings are no longer made turbid by solution of sodium hydrate. To the fil- tered liquid, concentrated to the volume of about 50 cubic centi- meters, when nearly cool, enough solution of sodium hydrate is added to render it strongly alkaline. The precipitate is col- lected on a wetted filter, allowed to drain, and washed with small portions of distilled water (using as little as possible), until the washings give but a slight turbidity with test solution of barium chloride, and the filter drained by laying it upon blotting or filter papers until it is nearly dry. The precipitate is then carefully detached from the filter, and transferred to a weighed capsule; the filter is washed with dis- tilled water acidulated with diluted sulphuric acid, the filtrate made alkaline with solution of sodium hydrate, and, if a precipi- tate results, this is washed on a very small filter, allowed to drain well, and also transferred to the capsule. The contents of the latter are now dried at 100° C. (212° F.) to a constant weight, 514 MANUAL OF CHEMICAL ANALYSIS. cooled in a desiccator, and weighed. The number of grams, mul- tiplied by 5, equals the percentage of total alkaloids in the cin- chona. To the total alkaloids from 20 grams of cinchona, previously weighed, distilled water acidulated with diluted sulphuric acid is added, until the mixture remains for 10 or 15 minutes after diges- tion just distinctly acid to test-paper. It is then transferred to a weighed beaker, rinsing with distilled water, and adding of this enough to make the whole weigh 70 times the weight of the alka- loids. Solution of sodium hydrate, previously well diluted with distilled water, is now added, in drops, until the mixture is exactly neutral to test-paper, digested at 60° 0. (140° F.), for 5 minutes, then cooled to 15° C. (59° F.), and maintained at this temperature for half an hour. If crystals do not appear in the glass vessel, the total alkaloids do not contain over 8 per cent, of their weight of quinine (corresponding to 9 per cent, of crystallized sulphate of quinine). If crystals appear in the mixture, the latter is passed through a filter not larger than necessary, prepared by drying two filter papers of 5 to 9 centimeters (2 to 3.5 inches) diameter, trimming them to an equal weight, folding them separately, and placing one within the other so as to make a plain filter four-fold on each side. When the liquid has drained away, the filter and contents are washed with distilled water of a temperature of 15° C.(59° F.), added in small portions, until the entire filtered liquid weighs 90 times the weight of the alkaloids taken. The filter is then dried, without separating its folds, at 60° C. (140° F.), to a constant weight, allowed to cool, and the inner filter and con.tents weighed, taking the outer filter for a counter-weight. To the weight of effloresced quinine sulphate so obtained, 11.5 per cent, of its amount is added (for water of crystallization!, and 0.12 per cent, of the weight of the entire filtered liquid added (for solubility of the crystals at 15° C., or 59° F.). The sum in grams, multiplied by 5, equals the percentage of crystallized quinine sulphate equiva- lent to the quinine in the cinchona. IV, Process of the Pharmacopoea Germanica: Twenty grams of the finely powdered bark are repeatedly and actively agitated with a mixture of 10 grams of ammonia-water,' spec. grav. 0.960, 20 grams of alcohol, spec. grav. 0.830 to 0.834, and 170 grams of ether, spec. grav. 0.724 to 0.728, and, after standing for a day, 120 grams of the liquid are poured off. After the addition of 3 cubic centimeters of normal hydrochloric acid (containing 36.5 grams HC1 in 1 liter), the ether is removed by distillation or evaporation, and, if necessary, so much hydrochloric acid added as is required to acidulate the solution.* This is then 2. For Quinine. * In consequence of the small amount of liquid obtained after the removal of the alcohol and ether, Prof. Fliickiger suggests that the solution be evaporated 515 QUININA. filtered, and the cooled liquid mixed with 8.5 cubic centimeters of normal solution of potassium hydrate (page 87). After the alka- loids have separated, solution of potassium hydrate is added to the clear supernatant liquid, until no further precipitate is pro- duced. The entire precipitate is finally collected upon a filter, and gradually washed with a little water until the drops of liquid escaping from the filter, when allowed to fall upon the surface of a saturated neutral solution of quinine sulphate in cold water, no longer produce a turbidity. After being allowed to drain, the alkaloids are gently pressed between bibulous paper, then dried by exposure to the air sufficiently to admit of bringing them into a glass capsule, in which they are placed over sulphuric acid, and finally completely dried in a water-bath. QUININiE HYDROBROMAS. CHININUM SEU CFIINIUM HYDROBROMICUM SEU IIYDROBROMAT UM. Hydrobromate of Quinine or Quinia. Quinine Hydrobromate. Ger. Bromwasserstoffsaures Cliinin ; Fr. Hydrobromate de quinine ; Sp. Bromliidrato de quinina. C20HJ4N202-HBr + 2H20; 440.8. Colorless, lustrous, prismatic, or needle-shaped crystals, con- taining two molecules (8.16 per cent.) of water of crystallization; they are permanent in ordinary air, but efflorescent in a warm atmosphere; when exposed to a moderate heat the salt fuses, and, when strongly heated, burns slowly away, leaving no residue. Quinine hydrobromate is soluble in about 16 parts of water, and in 8 parts of alcohol at 15° C. (59° F.); in 1 part of boiling water, and in less than 1 part of boiling alcohol; in 6 parts of ether, in 12 parts of chloroform, and moderately soluble in glyce- rine. The aqueous solution possesses a very bitter taste, is neu- tral in its action upon litmus, and, when acidulated with sulphuric acid, displays a blue fluorescence; if chlorine-water be added to the solution, and subsequently ammonia-water in excess, a bright emerald-green coloration is produced. The aqueous solution of quinine hydrobromate, if not too dilute, yields with ammonia-water a white precipitate of quinine, which is readily dissolved by an excess of the precipitant, or when to dryness, and the hydrochlorates ofthe alkaloids again taken up with 30 cubic centimeters of warm water, or, preferably, to apply originally 30 cubic centi- meters of decinormal hydrochloric acid, and by distilling off the alcohol and ether to concentrate the liquid to 30 cubic centimeters In all cases the alcohol and ether should be completely removed before the addition of the potassa solution. 516 MANUAL OF CHEMICAL ANALYSIS. mixed and agitated with ether; with argentic nitrate it yields a white precipitate of argentic bromide, which, when collected, and washed with a little water, is insoluble in diluted nitric acid, or in a solution of ammonium carbonate. Examination: With reference to its mode of preparation, quinine hydrobro- mate should be examined for its possible contamination with qui- nine sulphate, or with barium bromide, by acidulating its aqueous solution with nitric acid, and subsequently testing, in separate portions, with barium chloride for the former, and with diluted sulphuric acid for the latter. If either of these impurities are found, it will, of course, exclude the presence of the other. Water.—The presence of free water may be ascertained by the determination of the loss of weight upon drying 1 gram of the salt at the temperature of 100° C. (212° F.) until its weight remains constant. When dried at this temperature the residue should weigh not less than 0.918 gram, otherwise an undue per- centage of water is indicated. Quinidine, Cinchonine, and Cinchonidine.—One and one-half grams of the salt are dissolved in 15 cubic centimeters of hot dis- tilled water, the solution stirred with 0.6 gram of crystallized sodium sulphate in powder, the mixture maintained at 15° C. (59° F.) for half an hour, and then drained through a filter just sufficiently large to contain it until 5 cubic centimeters of filtrate are obtained. Upon proceeding further, as directed under Qui- nina, on page 506, the results there stated should be obtained. The further examination of quinine hydrobromate for other foreign organic or inorganic substances or alkaloids is the same as described under Quininse Sulphas, on pages 522, 523. CHININUM BISULFURICUM. CHININUM SEU CHINIUM SULFURICUM ACIDUM. QUININE BISULPHAS. Bisulphate of Quinine or Quinia. Acid Sulphate of Quinine. Quinine Bisulphate. Ger. Saures Scliwefelsaurcs Cliinin ; Fr. Sulfate acide de quinine ; Sp. Bisulfato de quinina. C„H!,N,0,.H,S0< + 7H,0 : 548. Colorless, transparent, prismatic crystals, belonging to the rhom- bic system, or small needles, efflorescent, and assuming an opaque whiteness on exposure to the air. The salt contains 7 molecules (22.99 per cent.) of water of crystallization, which are lost by drying at 100° C. (212° F.); when thus deprived of water, and heated in a small porcelain capsule, it melts at 135° C. (275° F.), QUININA. 517 and is converted into quinicine bisulphate; at a higher tempera- ture, it becomes yellow, then red, and is finally carbonized with the evolution of reddish vapors; when strongly heated on plati- num-foil, it burns slowly away, leaving no residue. Quinine bisulphate is soluble in about 10 parts of water and in 32 parts of alcohol at 15° C. (59° F.), and very freely soluble in boiling water and in boiling alcohol. Its aqueous solution pos- sesses an intensely bitter taste and an acid reaction, and displays a vivid blue fluorescence; with barium chloride it gives a white precipitate, insoluble in hydrochloric acid, and with chlorine- water followed by the addition of ammonia, a bright emerald- green color is produced; when ammonia-water is added to the solution, a precipitate is produced which is readily soluble in an excess of the precipitant, as also when mixed and agitated with ether. If to a solution of 1 part of quinine bisulphate in 20 parts of acetic acid and 5 parts of alcohol, a few drops of a saturated alco- holic solution of iodine are added, a precipitate of quinine iodo- sulphate, (C20H24lSr2O2)44- 3fl2S04 + 2III-f 41, or herapathite, will be produced; this compound forms thin laminar crystals or groups of stellate needles, of a bright green color and metallic lustre, and is very sparingly soluble in water and in alcohol. Examination: Water.—The presence of free water may be ascertained by the determination of the loss of weight upon drying 1 gram of the salt at the temperature of 100° 0. (212° F.) until its weight re- mains constant. When dried at this temperature, the residue of anhydrous quinine bisulphate so obtained should weigh not less than 0.77 gram, otherwise an undue percentage of water is indi- cated. Quinidine, Cinchonine, and Cinchonidine.—One gram of quinine bisulphate, previously dried at 100° C. (212° F.), is agitated with 8 cubic centimeters of distilled water, the mixture made exactly neutral to test-paper by the cautious addition of ammonia-water, and the volume of liquid increased to the measure of 10 cubic centimeters by the addition of distilled water. The mixture is then macerated at 15° C. (59° F.) for half an hour, when, upon proceeding further as directed under Quinina, on page 506, the results there stated should be obtained. The further examination of quinine bisulphate for other foreign organic or inorganic substances or alkaloids is the same as de- scribed under Quininse Sulphas, on pages 522, 523. 518 MANUAL OF CHEMICAL ANALYSIS. QUININ.ZB HYDROCHLORAS. QUINI.E MURIAS. CHININUM SEU CIIINIUM HYDROCHLORICUM SEU HYDROCHLORATUM Hydroclilorate of Quinine or Quinia. Quinine Hydroclilorate. Ger. Clilorwasserstoffsaures Chinin ; Fr Hydroclilorate de quinine ; Sp. Clorhidrato de quinina. C20H24N2O2.HCl + 2H20 ; 396.4. White, silky needles, or a crystalline powder, containing two molecules (9.08 per cent.) of water of crystallization; it is perma- nent at ordinary temperatures, but slightly efflorescent in a warm atmosphere; when heated to from 100 to 110° C. (212 to 230° F.) it loses its water of crystallization, fuses at a higher temperature, and, when strongly heated on platinum-foil, burns slowly away, leaving no residue. Quinine hydrochlorate is soluble in 34 parts of water and in 3 parts of alcohol at 15° C. (59° F.); in 1 part of boiling water, and very soluble in boiling alcohol; and also soluble in 9 parts of chloroform, in the latter instance accompanied by the separation of water; if, however, the salt be previously rendered anhydrous by gently heating, it requires but its own weight of chloroform for solution. The salt is also freely soluble in acidulated water, and in diluted as well as in concentrated acids, without change of color; its aqueous solution is neutral, possesses a bitter taste, and, when sufficiently diluted, displays a slight blue fluorescence on the addition of dilute sulphuric acid; with chlorine-water, fol- lowed by the addition of ammonia-water in excess, it affords a bright emerald green coloration, and if the ammonia-water is preceded by the addition of a few drops of a solution of potas- sium ferrocyanide, a red color is produced; the aqueous solution, acidulated with nitric acid, yields a white, curdy precipitate with argentic nitrate, soluble in an excess of ammonia-water, and a white precipitate with ammonia-water, which, however, is dis- solved by ether, alcohol, chloroform, or benzol, when added and agitated with the liquid. Examination: Water.—The presence of free water may be ascertained by the determination of the loss of weight upon drying 1 gram of the salt at the temperature of 100° C. (212° F.) until its weight re- mains constant. When dried at this temperature, the residue should weigh not less than 0.91 gram, otherwise an undue per- centage of water is indicated. Quinidine, Cinchonine, and Cinchonidine.—These associate alka- loids of quinine may readily be detected by Hesse's test, as de- scribed under Quininse Sulphas, on page 521. In the application of the test, 0.5 gram of quinine hydrochlorate and 0.25 gram of QUININA. 519 crystallized sodium sulphate are added to 10 cubic centimeters of water at 50-60° C. (122-140° F.), contained in a test-tube; the mixture is well shaken several times, and, after standing for ten minutes, 5 cubic centimeters of the clear filtered solution are introduced into a graduated tube (Fig. 154, page 521), 1 cubic centimeter of ether is added, and subsequently 5 drops of ammo- nia-water, spec. grav. 0.960. The tube is now closed with a cork, is agitated gently, and allowed to stand for several hours. If the ethereal layer is now examined with a lens, it should show no evidence of crystals; the separation of crystals being evidence of the presence of more than traces of the above-mentioned associate alkaloids. The detection of an admixture of the above-mentioned alka- loids may also be accomplished by the following method: 0.3 gram of the quinine hydrochlorate is agitated with 6 cubic centi- meters of distilled water, the mixture macerated at 15° C. (59° F.) for half an hour, and filtered; 4 cubic centimeters of the fil- trate are then diluted with 100 cubic centimeters of distilled water, and of the diluted solution 5 cubic centimeters are taken in a test-tube, and 7 cubic centimeters of ammonia-water, spec, grav. 0.960, added, without shaking; on gently turning the tube, closed by the finger, there should be formed, either at once, or after a short time, a clear liquid; an ensuing turbidity would indicate an admixture with the above-mentioned associate alka- loids of quinine. In consequence of the occasional occurrence of an accidental admixture or substitution of morphine hydrochlorate, the latter salt may also be tested for. It may readily be detected in the aqueous solution of the salt, by agitating it with a few drops of a solution of iodic acid, when, if morphine be present, iodine will be liberated, and upon subsequent agitation with a few drops of chloroform or carbon bisulphide, the characteristic violet color will be imparted to these liquids. The same reducing action may also be shown, by adding to the solution of the salt a few drops of a solution of potassium ferricyauide and ferric chloride, and subsequently hydrochloric acid in slight excess, when, in the pre- sence of morphine, a deep-blue coloration or precipitate will be produced. The presence of morphine, as also of many other foreign alka- loids or neutral principles, will likewise be indicated by a red or dark coloration in contact with concentrated nitric or sulphuric acid, whereas pure quinine hydrochlorate affords no coloration, or but a pale yellowish tint is produced. With reference to the method of its preparation, its aqueous solution needs, moreover, to be examined for contamination with quinine sulphate or with barium chloride, by acidulation with nitric acid, and subsequent testing, in separate portions, with barium nitrate for the former, and with diluted sulphuric acid 520 MANUAL OF CHEMICAL ANALYSIS. for the latter. Either of these impurities, of course, excludes the presence of the other, without impairing the solubility of the salt. The further examination of quinine hydrochlorate for quality and purity is the same as that of quinine sulphate, as described on pages 522, 523. QUININiE SULPHAS. CHININUM SEU CHINIUM SULFURICUM. Ger. Scliwefelsaures Cliinin ; Fr. Sulfate de quinine ; Sp. Sulfato de quinina. Sulphate of Quinine or Quinia. Quinine Sulphate. (G20H24N2O2)2H2SO4 + 7H2O; 872. Fine, silky, slightly flexible, snow-wliite needles, interlaced among one another, or grouped in small, star-like tufts ; the crys- tals contain seven molecules (14.45 per cent.) of water of crystal- lization, five of which (corresponding to 9.85 per cent.) are lost by long exposure to a warm and dry atmosphere, or more readily at a temperature of 50 to 60° C. (122 to 140° F.), while the re- maining two molecules (4.6 per cent.) are slowly expelled at a temperature of 100 to 115° C. (212 to 289° F.), and are again rapidly absorbed by exposure to the air; at a higher tempera- ture, crystallized quinine sulphate melts without decomposition, and, when strongly heated, becomes red, with the evolution of reddish vapors, becoming finally, upon ignition with access of air, slowly but wholly dissipated. Quinine sulphate is soluble in 740 parts of water and in 65 parts of alcohol at 15° C. (59° F.); in about 80 parts of boiling water, and in about 3 parts of boiling alcohol; in 40 parts of glycerin, in 1000 parts of chloroform, and very sparingly soluble in ether; it is very freely soluble in dilute or strong acids, form- ing colorless, bitter solutions, and its solution in sulphuric acid, when diluted, exhibits a bright blue fluorescence. Solutions of quinine sulphate are precipitated by the alkaline hydrates, carbonates, and bicarbonates, by lime-water, by tannic and picric acids, by potassium ferrocyanide, and by potassio-mer- curic iodide. The precipitates with calcium hydrate and with the alkaline hydrates are soluble in an abundance of the precipi- tant. Its solution in dilute hydrochloric acid gives, upon the addition of a solution of barium chloride, a white precipitate of barium sulphate, insoluble in nitric or hydrochloric acids. Like all quinine salts, quinine sulphate affords an emerald- green color, when to its dilute solution chlorine-water, and subsequently ammonia-water, in slight excess, are added ; if the addition of ammonia-water be preceded by a few drops of a solu- tion of potassium ferrocyanide, a red color will be produced. QUININA. 521 If, to a solution of 5 parts of quinine sulphate in 250 parts of warm alcohol, 2 parts of dilute sulphuric acid, and subsequently a solution of 2 parts of iodine in 20 parts of alcohol are gradu- ally added, a precipitate of quinine iodo-sulphate, or herapathite, (C2>I24N202)4 + 3H2S04+2HI + 4I + 3H20, will be produced. This compound is almost insoluble in water or cold alcohol, and, when crystallized from boiling alcohol, forms small laminas, with a green, metallic lustre. Examination: Water.—An undue proportion of water, with which the salt may have been moistened for the purpose of increasing its weight, may be detected by determining the loss of weight when dried at 100° C. (212° F.). One gram of the well-mixed salt, when dried at this temperature until the weight remains constant, should afford a residue weighing not less than 0.838 gram ; a greater loss of weight will indicate the presence of more than 8 molecules of water. Quinidine, Cinchonine, and Cmchonidine Sul- phates.—These associate alkaloids of quinine may readily be detected by the application of Hesse's test, which is based upon the fact that water at 50-60° C. (122-140° F.) dissolves quinine sul- phate but sparingly, while the sulphates of the other alkaloids are readily dissolved, and also that when the cooled solution, after supersaturation with ammonia-water, is shaken with a quantity of ether which is sufficient to dissolve all the qui- nine present, this quantity of ether is not sufficient to dissolve the other alkaloids if they exceed cer- tain limits. For executing this test a simple test-tube of the size represented in Fig. 154 may be employed. The internal diameter of the tube is about 1 centi- meter, and its height 12 centimeters. It is pro- vided with the marks B and C. The space below B (to A in the figure) has the capacity of 5 cubic centimeters, and the space between the lines B and C the capacity of 1 cubic centimeter. The application of the test is as follows : 0.5 gram of quinine sulphate and 10 cubic cen- timeters of water at 50-60° C. (122-140° F.) are shaken together in a test-tube several times. After standing for ten minutes, 5 cubic centimeters of the cooled and clear filtered solution are introduced into the graduated tube, 1 cubic centimeter of ether is added, and subsequently 5 drops of Fig. 154. 522 MANUAL OF CHEMICAL ANALYSIS. ammonia-water, spec. grav. 0.960. The tube is now closed with a tightly-fitting cork, is agitated gently, and allowed to stand for several hours; if the ethereal layer is now examined with a lens, it should show no evidence of crystals. The absence of crystals under the conditions named is evidence of sufficient purity ; but the salt may still contain 0.25 per cent, of cinchonine sulphate, 0.5 per cent, of quinidine sulphate, and about 1 per cent, of cinchonidine or homocinchonidine sulphates. If these alkaloids are present in larger quantities, crystals will separate in the ethereal layer, which are granular in the case of homocinchonidine or cinchonidine, and concentrically grouped needles if cinchonine or quinidine’. The two former, homocin- chonidine and cinchonidine, are most likely to be present in com- mercial quinine sulphate that is not intentionally adulterated, because of their liability to crystallize out along with the quinine in the course of manufacture, but they should not be present in an amount exceeding the above-named limits. If the above-mentioned associate alkaloids are present in the free state, they will remain for the most part undissolved when the quinine sulphate is treated with thirty times its weight of boiling water, and will also be indicated by a strong alkaline re- action of the hot aqueous solution with litmus-paper, whereas pure quinine sulphate is neutral in its action upon litmus. Mineral admixtures are detected by a residue left after igniting a little of the salt upon platinum-foil, or after dissolving a small portion of the salt in ten times its weight of boiling alcohol. Ammonium salts are recognized by the odor of ammonia, and by the formation of white vapors from a glass rod moistened with acetic acid, when held in the orifice of a test-tube, wherein a small portion of the quinine sulphate is heated with a strong solution of potassium hydrate. Chlorides and hydrocklorates may be recognized in the dilute solution of the salt in water, acidulated with nitric acid, by a white, curdy precipitate with argentic nitrate. Stearic acid may be detected in the above-described alcoholic solution, by adding an equal volume of water ; the liquid becomes turbid, but, on warming it gently, by dipping the test-tube in hot water, it becomes transparent again ; the appearance of an oily layer on the surface would indicate the above fatty acid. Salicin, sugar, and mannite may be detected in the solution of the preceding test, if free from fatty substances, by mixing it, in a porcelain capsule, with an amount of barium carbonate equal to that of the quinine sulphate employed, and evaporating the whole to dryness with constant stirring; the residue is triturated with a little water, and transferred upon a moist filter; the obtained filtrate is evaporated at a gentle heat, upon a watch-glass, and must leave no residue, or only a very small one; if a residue remains, it is divided, and placed upon two watch-glasses, with one drop QUININA. of water upon each, and is again allowed to evaporate at a gentle heat; then, upon the one glass, a small drop of concentrated sul- phuric acid is allowed to fall from a glass rod or from a small pipette (Fig. 155); a red color will be produced if scdicin is present, a black one if sugar; mannite remains un- changed, and may be detected on the second watch-glass, by a few drops of alcohol, which dissolve the mannite, and leave it behind in small, acicular crys- tals upon spontaneous evaporation. Since quinine sulphate dissolves with- out apparent change in strong sulphuric acid, even when gently warmed, this test may be directly applied for the de- tection of admixtures of sugar, mannite, or fatty acids, which will produce a black coloration; a red coloration might be indicative of the presence of salicin, but, since many other compounds produce a similar reaction, the following addi- tional test may be employed for salicin: A small portion of the quinine sul- phate is dissolved, in a test-tube, in about ten times its weight of water, acidulated with a few drops of concentrated hydrochloric acid ; the solution is boiled for a few minutes, when, if salicin be present, a white turbidity caused by the formation of saliretin will take place. Fig. 155. QUININE TANNAS. CHININUM SEU CHINIUM TANNIC UM. Ger. Gerbsaures Cbinin ; Fr. Tannate de quinine ; Sp. Tanato de quinina. Tannate of Quinine or Quinia. Quinine Tannate. C2oH24N2O3(CJ4H10O9)3+8H2O ; 1449. A yellowish-white, amorphous powder, which, when heated, becomes brown, fuses, and at a strong heat is wholly dissipated; it is only sparingly soluble in cold water, requiring 480 parts of it, but dissolves in about 50 parts of boiling water, forming a clear solution, which becomes turbid on cooling; the addition of acids increases the solubility to some extent; it is also quite sparingly soluble in boiling alcohol, ether, and chloroform, but quite readily soluble in warm glycerin; the alcoholic solution, when diluted with water, displays a slight blue fluorescence. The aqueous solution 524 MANUAL OF CHEMICAL ANALYSIS. of quinine tannate has an astringent, bitter taste, and a feebly acid reaction; it is precipitated by metallic salts, and assumes a bluish-black color upon the addition of a few drops of solution of ferric chloride. In contact with the alkaline hydrates, quinine tannate assumes a fine red color, accompanied by the separation of quinine; when treated with chlorine-water and ammonia, it does not afford directly the characteristic green color which is produced by most quinine salts, but, in consequence of the tannic acid, yields a transient red color. Examination: In consequence of the capability of tannic acid of forming very variable compounds with quinine, according to the proportion or manner in which it is employed, an examination of the salt should be made with reference to the amount of contained quinine, and its freedom from any appreciable amount of the associate alka- loids, quinidine, cinchonine, and cinchonidine. One gram of the quinine tannate is intimately mixed with twice its weight of caustic lime and sufficient water to form a stiff paste, and the mixture dried upon the water-bath; the residue is then powdered, repeat- edly extracted with hot chloroform, and the chloroformic solution evaporated in a tared beaker, dried at 120° C. (248° F.), and weighed. The residue should weigh not less than 0.22 gram. In order to determine the purity of the alkaloid thus obtained, the contents of the beaker are dissolved in a little water acidulated with a few drops of dilute sulphuric acid, filtered if necessary, and then shaken with 3 to 4 cubic centimeters of ether, and ammo- nia-water in excess. The two layers of liquid will remain clear if only quinine is present, while a greater or less turbidity is evi- denced in the presence of the other alkaloids. The residue from the chloroformic solution is also adapted to the qualitative deter- mination of quinine, by dissolving a small portion in chlorine- water, and subsequently adding a few drops of ammonia-water, when the characteristic emerald-green coloration will be produced; if the addition of ammonia-water be preceded by a few drops of a solution of potassium ferrocyanide, it assumes a bright red color. Admixtures of tannic or gallic acid, sugar, mannite, or dextrin may be recognized by their ready solubility in cold water in com- parison with that of quinine tannate. Starch is detected by a blue color, when one drop of solution of iodinized potassium iodide is added to a little of the quinine tannate shaken with some boiling water, and subsequently allowed to cool. 525 QUIN TNA. QUININiE VALERIAN AS. CHININUM SEU CHINIUM VALERIANICUM. Valerianate of Quinine or Quinia. Quinine Valerianate. Ger. Baldriansaures Chinin ; Fr. Valerianate de quinine ; Sp. Valerianato de quinina. C20H24N2O2-C5Hl0O2+H2O; 444. Thin, colorless, crystalline plates, of a pearly lustre, belonging to the triclinic system, having a faint odor of valerianic acid, and containing one molecule (4.04. per cent.) of water of crystalli- zation ; they are permanent in the air, fuse at about 90° C. (194° F.) to a colorless liquid, and lose their water of crystalli- zation at 100° C. (212° F.), becoming thereby partially decom- posed and incompletely soluble in water ; when strongly heated, they are entirely dissipated, emitting white, inflammable vapors. Quinine valerianate is soluble in about 100 parts of water at 15° C. (59° F.), and in 40 parts of boiling water; in 5 parts of cold, and 1 part of boiling, alcohol, but only sparingly in ether ; diluted acids dissolve it freely, and strong sulphuric acid does so without color, if heat is not applied. The aqueous solution of the salt pos- sesses a bitter taste, is neutral in its action upon litmus, and, when acidulated with sulphuric acid, displays a blue fluorescence with the development of the odor of valerianic acid; with ammonia-water it yields a white precipitate of quinine, which dissolves in a con- siderable excess of the reagent, as also readily upon agitation with ether. If chlorine-water be added to the solution, and subse- quently ammonia-water in slight excess, an emerald-green color is produced; if the addition of ammonia-water is preceded by a few drops of a solution of potassium ferrocyanide, it assumes a bright red color. Examination: Stearic acid, sugar, and scdicin are detected by agitating some of the quinine valerianate with strong sulphuric acid, in a test-tube ; a black coloration would indicate one or both of the two former; a red one, salicin. In the case of a black coloration, a special test for salicin has to be made ; a little of the valerianate is agitated with cold water, the filtrate is then evaporated at a gentle heat to a small volume, and this is strongly acidulated with a few drops of concentrated hydrochloric acid, and heated; a white turbidity, taking place after a while, would indicate salicin. Quinine hydrochlorate and sulphate may be detected, in the fil- tered aqueous solution of the salt, acidulated with a few drops of nitric acid, by testing portions of it with argentic nitrate for the former, and with barium nitrate for the latter. They will be in- dicated by a white precipitate with the respective reagent. 526 MANUAL OF CHEMICAL ANALYSIS. Zinc Valerianate or Acetate.—The absence of these or any other mineral salts, not readily volatilizable, maybe ascertained by ex- posing the salt to a red heat, upon platinum-foil, whereby the or- ganic matter is completely dissipated, leaving metallic oxides or carbonates behind, if such be present; if a residue remains which appears straw-yellow while hot and white when cold, it may be examined for zinc oxide by dissolving it, in a test-tube, in a few drops of diluted hydrochloric acid, supersaturating the solution with ammonia-water, and subsequently adding a little ammonium sulphide ; an ensuing white precipitate will confirm the presence of zinc. RESORCINUM. Ger. Resorcin ; Fr. Resorcine ; Sp. Resorcina. Resorcin. Meta-dioxybenzol. C.HeO,= C.H4(OH)4; no. A crystalline powder, or short, thick prisms of the rhombic system (Fig. 156), odorless and colorless when perfectly pure, but on exposure to the air assuming a pinkish color. It melts at 104° C. (219.2° F.), and boils at 271° C. (519.8° F.), but becomes par- tially volatilized at a much lower tempera- ture ; when heated on platinum-foil, it burns with a bright flame, and is finally completely dissipated. Resorcin is very readily soluble in water, alcohol, and ether, but is insoluble in chloro- form and carbon bisulphide. Its aqueous solution is neutral in its action on litmus, pos- sesses an intensely and disagreeably sweet taste, and assumes a dark violet color on the addition of ferric chloride, which disappears on the subsequent ad- dition of ammonia; chlorinated lime also produces a transient violet coloration. Its solution with ammonia-water by exposure to the air becomes rose-red, then brown, by evaporation at a gentle heat, green, finally dark blue, and, on the addition of an acid, again dark red. Resorcin reduces an ammoniacal solution of argentic nitrate and an alkaline cupric solution on boiling; upon the addition of bro- mine-water to its aqueous solution until a permanent turbidity is produced, small colorless needles of tribromresorcin, C6HBr3(OH)2, are separated, which are sparingly soluble in cold water, more readily in hot water, and freely soluble in alcohol. With acetyl, benzol, and succinyl chlorides, resorcin combines to form ether- Fig. 156. SALICINUM. 527 like compounds, in which the hydrogen atoms of the hydroxyl are replaced by acetyl, benzoyl, and succinvl groups, as, e. —32) 9 X '• If below freezing, but above 0° F. (—17.77° C.) _(32-D) 9 X)- x 5. 9 If below 0° F. (— 17.77° O'.) TABLES. TABLE FOR CONVERTING METRIC MEASURES OF CAPACITY INTO UNITED STATES FLUID MEASURES. Cubic centi- meters. Minims. Cubic centi- meters. Fluid ounces. Fluid dr'li ms. Minims. Cubic 1 centi- meters. Fluid ounces. Fluid dr’hms. Minims 0-01 0.16 0.65 10.55 46 1 4 26.40 0.02 0.32 0.70 11.36 47 1 4 42.60 0.08 0.49 0.75 12.17 48 1 4 58.80 0.04 0.65 0.80 12.98 49 1 5 15.00 0.05 0.81 0.85 13.80 50 1 5 31.80 0.0G 0.97 0.90 14.61 60 2 14.40 0.07 1.14 0.95 15.42 70 2 2 56.40 0.08 1.30 1 16.23 80 2 5 36.60 0.09 1.46 2 32-46 90 3 • . 21.00 0.10 1.62 3 48-69 100 3 3 3 60 0.11 1.79 4 i 4.80 110 3 5 46.20 0.12 1.95 5 i 21.00 120 4 28.20 0-18 2.11 6 l 37.20 130 4 3 8.40 0.14 2.27 7 l 53.40 140 4 5 52.80 0.15 2.43 8 2 9.60 150 5 35.40 0-16 2.60 9 2 25.80 160 5 3 18.00 0-17 2.76 10 o 42.60 170 5 6 0.18 2.92 11 2 58.83 180 6 40.20 0.19 3.08 12 3 15.06 1 190 6 3 24.60 0.20 3.25 13 3 31-29 200 6 6 7.20 0.21 3.41 14 3 57-40 225 7 4 52.85 0.22 3.57 15 4 18.60 250 8 3 39.00 0.28 3.74 16 4 19.80 275 9 2 24.65 0.24 3.90 17 4 36.00 300 10 1 10.80 0.25 4.06 18 4 52.20 325 10 7 56.40 0.26 4.22 19 5 8.40 350 11 6 42.60 0.27 4.39 20 5 24.60 375 12 5 28.20 0.28 4.55 21 5 40.83 1 400 13 4 14-40 0.29 4.71 22 5 57.06 ! 425 14 3 0.80 4.87 23 6 13.29 i 450 15 1 46.20 0.81 5.03 24 6 29.40 ! 475 16 . . 31.80 0.82 5.19 i 25 6 45.60 i 500 16 7 18.00 0.33 5.36 * 26 7 1.80 ! 525 17 6 3.60 0.34 5.52 27 7 18.00 550 18 4 49.80 0.35 5.68 28 7 34.20 575 19 3 35.40 0.36 5.84 29 7 50.40 600 20 2 21.60 0.37 6.01 30 i . , 4.80 625 21 1 17.20 0.38 6.17 31 i 21.03 650 21 7 53.40 0.39 6.33 32 i 37.26 675 22 6 49.00 0.40 6.49 33 i 53.49 700 23 5 25.20 0.41 6.65 34 i i 9.60 725 24 4 10.80 0.42 6.81 35 i 1 25.80 750 25 2 57.00 0.43 6.98 36 i l 42.00 775 26 1 42.60 0.44 7.14 37 i l 58.20 800 27 0 28.80 0.45 7.30 38 i 2 14.40 825 27 7 14.40 0.46 7.46 39 i 2 80.60 850 28 6 0.60 0.47 7.63 40 i 2 49.20 875 29 4 46.20 0.48 7.79 41 i 3 5.43 900 30 3 32.40 0.49 7.95 42 i 3 21.66 925 31 2 18.00 0.50 8.12 43 i 3 37.89 950 32 1 4.20 0.55 8.93 44 i 3 54.00 975 32 7 49.80 0.60 9.74 45 i 4 10.20 1000 33 6 36.00 TABLES. 607 TABLE FOR CONVERTING UNITED STATES FLUID MEASURES INTO METRIC MEASURES OF CAPACITY. Minims. Cubic centimeters. Minims. Fluid drachms. Cubic centimeters. Fluid ounces. Cubic centimeters. 1 0.06 43 2.64 3 88.67 2 0.12 44 2.71 4 118.24 3 0.18 45 2.77 5 147.81 4 0.25 46 2.83 6 177.39 5 0.31 47 2.89 7 206.96 6 0.37 48 2.95 8 236.53 7 0.43 49 3.01 9 266.10 8 0.49 50 3.08 10 295.68 9 0.55 55 3.39 11 325.25 10 0.62 60 3.70 12 354.82 11 0.68 65 4.01 13 384.40 12 0.74 70 4-31 14 413.97 13 0.80 75 4.62 15 443.54 14 0.86 80 4.93 16 473.11 15 0.92 85 5.24 17 502.69 10 0.99 90 5.54 18 532.26 17 . 1.05 95 5.85 19 561.93 18 1.11 100 6.16 20 591.50 19 1.17 no 6.78 21 621.08 20 1.23 120 7.39 22 650.65 21 1.29 3 11.09 23 680.22 22 1.36 4 14.79 24 709.80 23 1.42 5 18.48 25 739.37 24 1.48 6 22.18 26 768.94 25 1.54 7 25.88 27 798.51 26 1.60 8 29.57 28 828.09 27 1.66 9 33.27 29 857.66 28 1.73 10 36.97 30 887.23 29 1.79 11 40.66 31 916.80 30 1.85 12 44.36 946.38 31 1.91 13 48.06 40 1183.00 32 1.97 14 51.75 45 1330.81 33 2.03 15 55.45 48 1419.53 34 2.10 16 59.10 50 1478.74 35 2.16 17 62.85 55 1626.55 36 2.22 18 66.54 60 1774.46 37 2.28 19 70.24 64 1892.75 38 2.34 20 73.94 80 2366.00 39 2.40 21 77.63 96 2839.11 40 2.46 22 81.33 112 3312.22 41 2.52 23 85.03 128 3785.51 42 2.58 256 7571.02 TABLES. TABLE FOR CONVERTING METRIC WEIGHTS INTO TROY WEIGHTS. 0 © 50 00 -7 © Or 4^ CO to h- © O © o © © © © o o © © O o o © o © a © © O O © © O O o o o CO CO -7 © 4^ CO to H* o o © o o o O o © 3 CO GO •7 © Or 4^ CO to T t—a. U-A (—A © or CO to o 50 -7 © 4- CO 1—*■ cr* o co 4^ 00 CO CO to -7 © o Or CO to © CO -7 © 4^ CO h“L I-*- © © © © o o 3 S 45 •7 CO 00 4^ O Or k—5 -7 to CO 4x nr CO GO to “7 k—1 © © or CO to o CO -7 C5 4^ CO H-i to co Crr tO CO © to CO © CO GO 4^ O err •7 0D CD CO GO to •7 05 o Or © CO H* 50 © 4^ to CO -7 to CO © CO CO © CO o © CO co 4-* o © •7 CO CD 4^ * © 'f o -7 CO O -7 CO o a CO Ounce. 73 73 to to to to k—i k—5 M- gf to to : to k-5 Scruples. k—*■ 4-5. H-l k—5 H-A k-5 ►_A h-a JC < co *- GO CO GO to •7 k-A © o Or 42- to o CO •7 © 4* CO k—A k-5 k—1 k-A y. a- oi<° toH cn.cc Oi|M 4-jCo **,M o<;4* tC|~ WH Hen ©1° rfHw w| Wjr-* C.|M Grains. te- es ' o co 00 -7 © Or 4— 4^ CO CO CO tO to to to to to to to to to >—i k—5 k-5 k—5 k—5 o o © O O O O or O to o CO OD © Or 4X CO to o CO GC -7 C5 Or 45* CO to & © © © o © © © o © © <=• © © o © © ’© © © o O o O © O © O o o 1 H-t V—L h—* |—A or #co to 50- -7 © © 4^ 4^ 4- 45* 4~ 4^ CC CO CO CO CO CO to to to to to to to 4^ GC CO oo to CO CO -7 © 4— CO o OD -7 Or oo to o CO “7 © 4-* CC o OD “pi© CO 00 4^ o Or 4^ -7 CO CO to to © Cr o 45* CO 45* (JO oo •7 to Oi C5 o Or ? y 5 to co Of to CO © 4- to GO C- co Of ►_A © to GO CO co Or o © to “7 CO CO A- o Ci b < CO OD © 4^ Or CO CO o CO o -7 4- O -7 4- -7 4-* C3D Or GO Or to 00 /- p 7 Or H-1 00 4-* t—* -7 © 4- Or cc © (JO © CO k—*• CO © 4-* to CO or to o GC or CO t—* 00 CO to to to - M- l-± 1—5 Ounces. > 73 c S 4* to 4- CO to • nvier amongst his books, and he will find it invaluable for reference in working up his case-; in fact, a great deal of well-condensed matter is collected together here which is not easily found in the same form anywhere else. — Can. Med. and Surg. Journal, June, 1880. Their book is not a collection of the works of others, but has been written in the laboratory be- side the microscope. It bears the marks of personal knowledge and investigation upon every page, con- trolled by and controlling the work of others. In short, its translation has made it the best work Iti pathology attainable in onr language, one that every ■.trident certainly ought to have.—Archives of Med- icine., April, 1880. We have no hesitation in cordially recommend- ing he translation of Cornil and Ranvier’s Patho- logical Histology” as the best work of the kind in any language, and as giving to its readers a trustworthy guide in obtaining a broad and solid basis for the appreciation of the practical bearings of pathological anatomy.—Am. Journ. of Med. Sciences, April, 1880. This important work, in its American dress, is a welcome offering to all students of the subjects which it treats. The great mass of material is arranged naturally and comprehensively. The classification of tumors is clear and full, so far as the subject Admits of definition, and this one chap- ter is worth the price of the book. The illustra- tions are copious and well chosen. Without the slightest hesitation, the translators deserve honest thanks for placing this indispensable work in the hands of American students.—Phila. Med. Times, April 24, 1880. This volume we cordially commend to the profes- sion. It will prove a valuable, almost necessary, addition to the libraries of students who are to he physicians, and to the libraries of students who are physicians.— American Practitioner, June, 1880. The best and most complete wor-k ever issued on the subject from the pres- of any country. — London Medical Press and Circular. UOHAFER (ED WA RD ALBERT), M.D., Assistant Prof essor of Physiology in University College, London. A COURSE OF PRACTICAL HISTOLOGY: Being an Introduction to the Use of the Microscope. In one handsome royal 12mo. volume of 308 pages, with numerous illustrations. Cloth, $2 00. (1REEN (T. HE NR Y),M.D„ Lecturer on Pathology and Morbid Anatomy at Charing-Cross Hospital Medical School, etc. PATHOLOGY AND MORBID ANATOMY. • Fifth American,from the Sixth Enlarged and Revised English Edition. In one very handsome octavo volume of about 350 pages, with about 150 fine engravings. (Preparing.) A few notices of the previous edition are appended. No late discovery or investigation has been over- looked, and the illustrations are the best that ever accompanied any book on tho subject In few de- partments of medicine has so much progress been made of late as io that of pathology, supported as it is hy the promising sciences of biology and physio- logical chemistry, and these lie at the basis of sci- entific treatment. It will repay most practitioners to peruse this book at least two or three times.— Chicago Med. Journ. and Examiner, Feb., 18S2. All the good thiugs that have been said and writ- ten of previous editions apply with added force to this, and we know not how to recommend the book too highly to all students and to these practitioners who have not a recent edition, and who care to know the why and wherefore of those processes which fall nnder their daily observation.—Can. Journ. of Med. Science, Aug. 18S1. Henry C. Lea’s Son & Co.’s Publications—(Practice, etc.). 14 IDRIS TO WE (JOHN SFER), M.D , F.R.C.P., ID Physician and Joint Lectzirer on Medicine at St. Thomas' Hospital. A TREATISE ON THE PRACTICE OF MEDICINE. Second American Edition, revised by the Author. Edited, with Additions, by James H. Hutch- inson, M.D., Physician to the Penna. Hospital. In one handsome octavo volume of 1085 pages, with illustrations. Cloth, $5 00; leather, $6 00; half Russia, raised bands, $6 50. (Lately Issued.) The second edition of this excellent work, lik e the first, has received the benefit of Dr. Hutchinson’s annotations, by which the phases of disease which are peculiar to this country are indicated, and thus a treatise which was intended for British practi- tioners and students is made more practically useful on this side of the water. We see no reason to modify the high opinion previously expressed with regard to Dr. Brist.owe’s work, except by adding our appreciation of the careful labors of the author in following the latest growth of medical science. — Boston Medical and Surgical Journal, February, 1880 What we said of the first edition, we can, with i no reased emphasis, repeat concerning this: “Every page is characterized by the utterances of a thought- ful man. What has been said, has been well said, and the book is a fair reflex of all that is certainly knr.yon on the subiects considered.”—Ohio Med. Recorder, Jan. 7, 1880. The reader will find every conceivable subject connected with the practice of medicine ably pre- sented, in a style at once clear, interesting and con- cise. The additions made by Dr. Hutchinson are appropriate and practical, and greatly add to its usefulness to American readers.—Buffalo Med. and Burg. Journ., March, 18S0. We regard it as an excellent work forstudents and for practitioners. It is clearly written, the author’s style is attractive, and it is especially to be com- mended for its excellent exposition of the pathology and clinical phenomena of disease.—St. Louis Clin. Record, Feb. 1880. LIEN WICK (SAMUEL), M.D., Assistant Physician to the London Hospital. THE STUDENT’S GUIDE TO MEDICAL DIAGNOSIS. From the Third Revised and Enlarged English Edition. In one very handsome royal 12mo. volume of 328 pages, with 87 illustrations on wood. Cloth, $2 25. LIOTHERG1LL (J. MILNER), M.D. Edin., M.R.C.P. Lond., I Asst. Phys. to the West Lond IIosp.: Asst. Phys. to the City of Lond. Hasp.,etc. THE PRACTITIONER’S HANDBOOK OF TREATMENT; Or, The Principles of Therapeutics. Second Edition, revised and enlarged. In one very hand- some octavo volume of about 650 pages. Cloth, $4 00; very handsome half Russia, raised bands, $5 50. (Just Issued.) A book which can give correctly and interestingly as well as scientifically, the method of prescribing aud the rationale of the best therapeutics in the treatment of disease, is manifestly just the work, which each physician desires. It is not extrava- gant eulogy to say that the physician will find in tiiis work of Ftthergill ihe guide which he seeks for his therapeutics ; tor not only is the treatment which he seeks already indicated herein, but the rationale of the treatment is as clearly explained. — Gaillard's Med. Journ., Sept. 1880. The author merits the thaDks of every well-edu- cated physician for his efforts toward rationalizing the treatment of diseases upon the scientific basis of physiology. Every chapter, every line, has the impress of a master hand, and while the work is thoroughly scientific in every particular, it presents to the thoughtful reader all the charms and beau- ties of a well-written novel. No physician can well afford to be without this valuable work, for Us originality makes it fill a niche in medical litera- ture hitherto vacant.—Nashville Journ. of Med. and Surg., Oct. 18S0. The junior members of the profession will find in it a work that should not only be read, brU care- fully studied. It will assist them in the proper selection and combination of therapeutical ageuts best adapted to each case and condition, and enable them to prescribe intelligently and successfully. To do full justice to a work of this scope and char- acter will be impossible in a review of this kind. The book itself must be read to be fully appreciated —St. Louis Courier of Medicine, Nov. 1880. Both in matter and manner the book is most thor- oughly excellent.—Ohio Med. Recorder, Oct. 18S0. LJABERSHON (S. O.) M.D. Senior Physician to and late Lecturer on the Principles and Practice of Medicine at Guy's Hospital, etc. ON THE DISEASES OF THE ABDOMEN, COMPRISING THOSE of the Stomach, and other parts of the Alimentary Canal, (Esophagus, Caecum, Intes- tines and Peritoneum. Second American, from the Third Enlarged and Revised Eng- lish Edition. With illustrations. In one handsome octavo volume of 554 pages, with illustrations. Cloth, $3 50. (Lately Issued.) This valuable treatise on diseases of the stomach a nd abdomen has been out of print for several years, and is therefore not so well known to the profession as it deserves to be. It will be found a cyclopaedia of information, systematically arranged, on all dis- eases of the alimentary tract, from the mouth to the rectum A fair proportion of each chapter is devoted to symptoms, pathology and therapeutics. The present edition is fuller than former ones in many particulars, and has been thoroughly revised and amended by the author. Several new chapters have been added, bringing the work fully up to the times, and making it a volume of interest to the practi- tioner in every field of medicine and surgery. Per- verted nutrition is in some form associated with all diseases we have to combat, and we need all the light that can he obtained on a subject so broad and general. Dr. Habershon’s work is one that every practitioner should read and study for himself.— N. Y Med. Journ , April, 1879. « LUGE’S ATLAS op PATHOLOGICAL HISTOLOGY. Translated, with Notes and Additions, by Joseph Leidy, M. D. In one volume, very largeimperiai rjuarto, witli 320 copper-plate figures, plain and colored. Clotb, $4 00. HOLLAND’S MEDICAL NOTES AND REFLEC- TIONS. 1 vol. 8vo . pp 500. Cloth, *3 50. BARLOW’S MANUAL OF THE PRACTICE OF MEDICINE. With Additions by D. F. Condie, M.D. 1 vol. 8vo. pp.600. Cloth, $2 50. LA ROCHE ON YELLOW FEVER,considered in its Historical, Pathological, Etiological and Thera- peutical Relations. In two large and handsome octavo volumes of nearly 1 500 pp. Cloth,$7 00. LA ROCHE ON PNEUMONIA. 1 vol.8vo. of 490 pages Cloth, $3 00. PAVY’S TREATISE ON THE FUNCTION OF DI- GESTION: its Disorders and their Treatment. From the Second London Edition In one hand- some volume, small octavo. Cloth, $2 00. Henry C. Lea’s Son & Co.’s Publications—{Practice of Medicine). 15 fiTLINT (A USTIN), M.D., Professor of the Principles and Practice of Medicine in Bellevue Med. College, N. Y. A TREATISE ON THE PRINCIPLES AND PRACTICE OF MEDICINE ; designed for the use of Students and Practitioners of Medicine. Fifth Edition, entirely rewritten and much improved.' In one large and closely printed octavo volume of 1150 pages. Cloth, $5 50; leather, $6 50; very handsome half Russia, raised bands, $7. (Just Issued.) This work has been so long and favorably known, and has obtained so high a position amongst mod- ern treatises on medicine, that it is hardly neces- sary to do more than announce the publication of this fifth edition. All who peruse it must be struck by the extensive research which has been under- taken in the revision of this edition, combined with much original thought. There is hardly a subject which does not receive fresh illustration and discus- sion, opening up new lines of inquiry which had not been thought of when the previous edition appeared. We cannot conclude this notice without expressing our admiration of this volume, which is certainly one of the standard text-books on medicine, and we may saf'elv affirm that, taken altogether, it exhibits a fuller and wider acquaintance with recent patho- logical inquiry than any similar work with which wo are acquainted, whilst at the same time it shows its author to be possessed of the rare faculties of clear exposition, thoughtful discrimination, and sound judgment.—London Lancet, July 23, I SSI. Practically, this edition is a new work; for so many additions and changes have been made that one well acquainted with previous editions would hardly recognize this as an old friend. The size of the volume is somewhat increased. An entire new section and several new chapters have been added. It is universally conceded that no text book upon this subject was ever published in this country that can at all compare with it It has long been at the very head of American text-book literature, aud there can be no doubt but that it will be many years before it yields the place to others.—Nash- ville Journ. of Med. and Surg , Feb. 1881. “Flint’s Practice’’ is recognized to be a standard treatise of high rank upon the principles and the practice of medicine wherever the English language is read. The opinions everywhere reveal the man of extensive experience, diligent study, calm judg- ment, and unbiassed criticism. The work should be in the hands of every practitioner. — New Turk Med. Record, Feb. 26, 1881. The style aud character of this work are too well known to the profession to require an introduction. For a number of years this volume has occupied a leading position as a text-book in the majority of medical schools, and the high position accorded to it in the past is a guarantee of a hearty welcome in this new edition. The book may be said to represeat the present state of the science of medicine as now understood and taught. Itis a safe guide to students and practitioners of medicine.—Maryland Medical Journal, March 1, 1SSI. The author has, in this edition, revised and re- written a great oart and made it accord with the more advanced ideas which have been developed within the past few years. He is fhe more fitted to do so, as he is actively engaged in his profession, and can make deductions, not from the work of others, but from his own labors. It is a treatise which every American physician should bare upon his table, and which he should consult on occasions when his leisure permits him to do so.—St. Louis Med a.nd Surg. Journal, March, 1881. T THE SAME AUTHOR. CLINICAL MEDICINE; a Systematic Treatise on the Diagnosis and Treatment of Diseases. Designed for Students and Practitioners of Medicine. In one large and handsome octavo volume of 799 pages. Cloth, $4 50 ; leather, $5 50; half Russia, $6. (Lately Issued.) The eminent teacher who has written the volume under consideration has recognized the needs of the American profession, and the result is all that we could wish. The style in which it is written is peculiarly the author’s; it is clear and forcible, and marked by those characteristies which have ren- dered him one of the best writers and teachers this country has ever produced. We have not space for so full a consideration of this remarkable work as we would desire.—St. Louis Clin. Record, Oct. 1879. It is here that the skill and learning of the great clinician are displayed He has given ns a store- house of medical knowledge, excellent for the stu- dent, convenient for the practitioner, the result of a long life of the most faithful clinical work, collect- ed by an energy as vigilant and systematic as un- tiring, and weighed by a judgment no less clear than his observation is close.—Archives of Medi- cine, Dec. 1879 To give an adequate and useful conspeotus of the extensive field of modern clinical medicine is a task of no ordinary difficulty; bat to accomplish this consistently with brevityand clearness,the different subjects and their several parts receiving the atten- tion which, relatively to their importance, medical opinion claims for them,is still more difficult. This task we feel bound to say has been executed with more than partial success by Dr Flint, whose name is already familiar to students of advanced medicine in this country as that of the author of two works of great merit on special subjects, and of numerous papers, exhibiting much originality aud extensive research. — The Dublin Journal, Dec. 1S79. There is every reason to believe that this book will be well received. The active practitioner is frequently in need of some work that will enable him to obtain information in the diagnosis and treatment of cases with comparatively little labor. Dr. Flint has the faculty of expressing himself clearly, and at the same time so concisely as to enable the searcher to traverse the entire ground of his search, and at the same time obtain all that is essential, without plodding through an intermi- nable space.—N. Y. Med. Jour., Nov. 1879 The great object is to place before the reader the latest observations and experience in diagnosis and treatment. Such a work is especially valuable to students. Itis complete in its special design, and yet so condensed, that he can by its aid, keep up with the lectures on practice without neglecting other branches. It will not escape the notice of the practitioner that such a work is most valuable in culling points in diagnosis and treatment in the in- tervals between the daily rounds of visits, since he can in a few minutes refresh his memory, or learn the latest advance in the treatment of diseases which demand his instant attention.—Cincinnati Lancet and Clinic, Oct. 25, 1879. nT THE SAME A UTHOR. ESSAYS ON CONSERVATIVE MEDICINE AND KINDRED TOPICS. In one very handsome royal 12mo. volume. Cloth, $1 38. DAVIS’ CLINICAL LECTURES ON VARIOUS IM-li PORTANf DISEASES; beluga collection of the Clinical Lectures delivered in the Medical Wards of Mercy Hospital, Chicago. Edited by Frank H. Davis, M.D. Second Edition, enlarged. In one ! handsome royal 12mo. volume. Cloth, SI 75. CHAMBERS’ MANUAL OF DIET AND REGIMEN IN HEALTH AND SICKNESS. In one handsome octavo volume. Cloth, $2 75. ' STURGES’ INTRODUCTION TO THE STUDY OF CLINICAL MEDICINE. Being a Guide to the In- vestigation of Disease. In one handsome 12mo. : volume. Cloth, $1 25. TODD’S CLINICAL LECTURES ON CERTAIN ACUTE DISEASES. In one octavo volume, of 329 pages. Cloth, $2 50. 16 IJICF1ARDSON {BENJ. IF.), M.A., M.D., LL.D., F.R.S., F.S.A., -R Fellow of the Royal College of Physicians, London. PREVENTIVE MEDICINE. In one octavo volume of about 500 pages. (Preparing.) Henry C. Lea’s Son & Co.’s Publications—{Practice of Medicine). HARTSHORNE {HENRY), M.D., late. Professor of Hygiene in the. University of Pennsylvania ESSENTIALS OF THE PRINCIPLES AND PRACTICE OF MEDI- CINE. A handy book for Students and Practitioners Fifth Edition, thoroughly re- vised and rewritten. In one handsome royal 12mo. volume, of 669 pages, with 144 illus- trations. Cloth, $2.75 ; half hound, $3.00. (Just Heady.) The very great success which has exhausted four large editions of this work shows that the author has succeeded in supplying a want felt by a large portion of the profession. It has also enabled him in successive revisions to perfect the details of his plan, and to render the work still more worthy of the favor with which it has been received. In the present edition several hundred brief additions have been made, a number of new subjects have been written upon, especially in connection with the Pathology of the Nervous System, the illustrations have been considerably increased, and a large number of new and carefully selected formulas for the admi- nistration of medicines have been introduced. An account is given, also, in this edition for the first time, of the method of prescribing according to the metrical system, and a section is added upon Eyesight, its Examination and Correction. In presenting this edition, therefore, the pub- lishers feel that it is in every way worthy a continuance of the favor hitherto accorded this work. The author of this book seems to have spared no pains to bring it up to the modern standpoint, for as we turn over its pages we find many subjects intro- duced which have only lately been brought before the profession. Certainly amongst books of its class it deserves and has obtained a good position. On the whole it is a careful and conscientious piece of work, and may be commended.—Lancet, June 24, 1882. As to the popularity of the fifth edition of a med- ical work, nothing need be said. Concerning the one before us, we need only to say that the author has exercised the same good judgment as was ap- parent in former editions, and that all recent addi- tions to this field have been laid under contribu- tion to fill its pages. As a brief compend of the essentials of practical medicine, we have never seen the superior to this work. Used in a proper- manner it will be of great service to both medical students and practitioners. So thoroughly has be digested his materials, and so attractively has he arranged them, that it is a real pleasure to read his work. We can cordially commend it to the favor- able attention of such as may desire the aid of its pages. That it will be even more helpful in its present form than it was in former editions we fully believe.—Detroit Lancet, Dec. 1881. The style is condensed and terse, yet simple and perspicuous. The author has skilfully picked out the kernel from the nut and thrown aside the shells. To the every-day practitioner it is a ready help, and a thorough study of the subject, will be greatly facilitated by a previous perusal of the essentials. The present edition ;is a great improvement on its predecessors—in fact almost a new book.—Pacific Med. and Surg. Journal, Jan. 1882. WOODBURY (FRANK), M.D., ’ ’ Physician to the German Hospital, Philadelphia; late Chief Assistant to the Medical Clinic in Jefferson College Hospital, etc. A HANDBOOK OF THE PRINCIPLES AND PRACTICE OF Medicine ; for the use of Students and Practitioners. In one royal 12mo. volume, with illustrations. (Preparing.) TpINLA YSON {JAMES), M.D., * Physician and Lecturer on Clinical Medicine in the Glasgow Western Infirmary, etc. CLINICAL DIAGNOSIS; A Handbook for Students and Prac- titioners of Medicine. In one handsome 12mo. volume, of 546 pages, with 85 illustra- tions. Cloth, $2 63. {Lately Issued.) The book is an excellent one,clear, concise, conve- nient, practical. It is replete with the very know- ledge the student needs when he quits the lecture- room and the laboratory for the ward and sick-room, and does not lack in information that will meet the wants of experienced and older men.—Phila. Med. Times, Jan. 4, 1879. This is one of the really useful books. It is attrac- tive from preface to the final page, and ought to be gi ven a place on every office table, because it contains in a condensed form all that is valuable in semeiology and diagnostics to be found in bulkier volumes, and because in its arrangement and complete index, it is unusually convenient for quick reference in any emergency that may come upon the busy practitioner. —N. C. Med. Juurn., Jan. 1879. WATSON {THOMAS), M.D. LECTURES ON THE PRINCIPLES AND PRACTICE OF PHYSIC. Delivered at King’s College, London. A New American, from the Fifth English Edition, revised and enlarged. Edited, with additions, and 190 illustrations, by Henry Hartshorne, A.M., M.D., late Professor of Hygiene in the University of Penn- sylvania. In two large and handsome octavo volumes. Cloth, $9 00 ; leather, $11 00. WILLIAMS ON PULMONARY CONSUMPTION; its Nature, Varieties and Treatment. With an Ana- lysis of One Thousand Cases to exemplify its duration. In one octavo volume of about 350 pages. Cloth, $2 50. SLADE ON DIPHTHERIA; its Nature and Treat- ment, with an account of the History of its Pre- valence iu various Countries. Second and Revised Edition. In one royal 12mo. volume. Cloth, tBl 25. WALSHEON THE DISEASES OF THEHEART AND GREAT VESSELS. Third American Edition. In 1 vol. Svo., 420 pp. Cloth, $3 00. SMITH ON CONSUMPTION ; ITS EARLY AND RE- MEDIABLE STAGES. 1 vol. Svo..pp. 254. *2 25. FULLER ON DISEASES OF THE LUNGS AND AIR- PASSAGES. Their Pathology, Physical, Diagnosis, Symptoms and Treatment. From the Second and Revised English Edition. In one handsome octavo volume of about 500 pages. Cloth, $3 50. Henry C. Lea’s Son & Co.’s Publications—(Practice of Medicine). 17 REYNOLDS (J. RUSSELL). M.D., A 1 Prof. of the Principles and Practice of Medicine in Univ. College, Lond,on. A SYSTEM OF MEDICINE with Note? and Additions by Henry Harts- horne, A.M., M.D , late Professor of Hygienein the University of Penna. In three large and handsome octavo volumes, containing 3056 closely printed double-columned pages, with 317 illustrations. Price per vol., cloth, $5.00 ; sheep, $6.00: very handsome half Russia, raised bands, $6.50. Per set, cloth, $15; sheep, $18; half Russia, $19.50. (Sold only by subscription.) Volume I. (now ready) contains General Diseases and Diseases of theNervous System Volume II. (now ready) contains Diseases of Respiratory and Circulatory Systems. Volume III. (now ready) contains Diseases of the Digestive and Blood-Glandular Systems, of the Urinary Organs, of the Female Reproductive System, and of the Cutaneous System. Reynolds’ System of Medicine, recently completed, has acquired, since the first appearance of the first volume, the well-deserved reputation of being the work in which modern British medicine is presented in its fullest and most practical form. This could scarce be otherwise in view of the fact that it is the result of the collaboration of the leading minds of the profession, each subject being treated by some gentleman who is regarded as its highest authority—as for instance, Diseases of the Bladder by Sir Henry Thompson, Malpositions of the Uterus by Graily Hewitt, Insanity by Henry Maudsley, Consumption by J. Hughes Bennet, Dis- eases of the Spine by Charles Bland Radcliffe, Pericarditis by Francis Sibson, Alcoholism by Francis E. Anstie, Renal Affections by William Roberts, Asthma by Hyde Salter, Cerebral Affections by II Charlton Bastian, Gout and Rheumatism by Alfred Baring Gar- rod, Constitutional Syphilis by Jonathan Hutchinson, Diseases of the Stomach by Wilson Fox, Diseases of the Skin by Bai.manno Squire, Affections of the Larynx by Morell Mac- kenzie, Diseases of the Rectum by Blizard Curling, Diabetes by Lauder Brunton, Intes- tinal Diseases by John Syer Bristowe, Catalepsy and Somnambulism by Thomas King Cham- bers, Apoplexy by J. Hughlings Jackson, Angina Pectoris by Professor Gairdner, Emphy- sema of the Lungs by Sir William Jenner, etc. etc. All the leading schools in Great Britain have contributed their best men in generous rivalry, to build up this monument of medical sci- ence. St. Bartholomew’s, Guy’s, St. Thomas’, University College, St. Mary’s, in London, while the Edinburgh, Glasgow and Manchester schools are equally well represented, the Army Medical School at Netley, the military and naval services, and the public health boards. That a work conceived in such a spirit, and carried out under such auspices should prove an indispensable treasury of facts and experience, suited to the daily wants of the practitioner, was inevitable, and the success which it has enjoyed in England, and the reputation which it has acquired on this side of the Atlantic, have sealed it with the approbation of the two pre-eminently practical nations. Its large size and high price having kept it beyond the reach of many practitioners in this country who desire to possess it, a demand has arisen for an edition at a price which shall ren- der it accessible to all. To meet this demand the present edition has been undertaken. The five volumes and five thousand pages of the original have, by the use of a smaller type and double columns, been compressed into three volumes of over three thousand pages, clearly and hand- somely printed, and offered at a price which renders it one of the cheapest works ever presented to the American profession. But not only is the American edition more convenient and lower priced than the English ; it is also better and more complete. Some years having elapsed since the appearance of a portion of the work, additions are required to bring up the subjects to the existing condition of science. Some diseases, also, which are comparatively unimportant in England, require more elaborate treatment to adapt the articles devoted to them to the wants of the American physi- cian ; and there are points on which the received practice in this country differs from that adopted abroad. The supplying of these deficiencies has been undertaken by Henry Harts- horne, M.D.,late Professor of Hygiene in the University of Pennsylvania, who has endeavored to render the work fully up to the day, and as useful to the American physician as it has proved to be to his English brethren. The number of illustrations has also been largely increased, and no effort spared to render the typographical execution unexceptionable in every respect. Really too much praise can scarcely be given to this noble book. It is a cyclopaedia of medicine written by some of the best men of Europe. It is full of useful information such as one finds frequent need of in one’s daily work As a book of reference it is invaluable. It is up with the times. It is clear and concentrated in style, and its form is worthy of its famous publisher. — Louisville Med. News, Jan. 31, 1880. “Reynolds’ System of Medicine” is justly con- sidered the most popular work on the principles and practice of medicine in the English language The contributors to this work are gentlemen of well- known reputation on both sides of the Atlantic. Each gentleman has striven to make his part of the work as practical as possible, and the information contained is such as is needed by the busy practi- tioner.— St. Louis Med. and Sure/. Journ., Jan. ’80. Dr. Hartshorne has made ample additions and revisions, all of which give increased value to the volume, and render it more useful to the Ameri- can practitioner There is no volume in English medical literature more valuable, and every pur- chaser will, on becoming familiar with it, congrat- ulate himself on the possession of this vast store- house of information, in regard to so many of the subjects with which he should be familiar-—Gail- lard's Med. Journ., Feb. 1880. There is no medical work which we have in times past more frequently and fully consulted when per- plexed by doubts as to treatment, or by having un- usual or apparently inexplicable symptoms pre- sented to us than “Reynolds’ System of Medicine.” Among its contributors are gentlemen who are as well known by reputation upon this side of the Atlantic as in Great Britain, and whose right to speak with authority upon the subjects about which they have written, is recognized the world over. They have evidently striven to make their essays as practical as possible, and while these are sufficiently full to entitle them to the name of monographs, they are not loaded down with such an amount of detail as to render them wearisome to the general reader. In a word, they contain just that kind of information which the busy practitioner frequently finds himself in need of. in order that any deficiencies may be supplied, ihe publishers have committed the preparation of the book for the press to Dr. Henry Hartshorne, whose judicious notesdistributed throughout the volume afford abun- dant evidence of the thoroughness of the revision to which he has subjected it—American Journalof the Medical Sciences, Jan. 1880. 18 Henry C. Lea’s Son & Co.’s Publications—(New. Dis., (fee.). UARTHOLOW {ROBERTS), A M., M.D.. LL.D., J..J' Prof, of Materia Medica and General Therapeutics in the Jefferson Med. Coll, of Phila., etc. A PRACTICAL TREATISE ON ELECTRICITY IN ITS APPLI- CATION TO MEDICINE. Secon I Edition. In one very handsome octavo volume of 296 pages, with 109 illustrations. Cloth, $2 50. {Just Ready.) From the Preface to the Second Edition. In the present edition I have made many additions and improvements to render the work more useful to those for whom it is intended. At the same time, in response to what seems to me an increasing desire for scientific treatment, I have developed more fully the modern methods of ascertaining and expressing current strength, tension, resistances, etc. I have also entered more fully into the polar method, and into the action and uses of the magnet. Notwithstand- ing an increase in the number of lines to the page, and the condensation of the matter new and old, the work has enlarged by the addition of thirty pages. Thus improved, I may be permitted to hope that the new edition will continue to enjoy the favor so largely bestowed on the first. The second edition of this work following so soon upon the first, would in itself appear to be a suffi- cient announcement; nevertheless, the text has been so considerably revised and condensed, and so much enlarged by the addition of new matter, that we cannot fail to recognize a vast improvement upon the former work. The author has prepared his work for students aud practitioners; for those who have never acquainted themselves with the subject, or having done so, find that after a time their knowledve needs refreshing. We think he ! has accomplished his object The book is not too voluminous, but is thoroughly practical, simple, 1 complete and comprehensible. It is, moreover, re- ! plete with numerous illustrations of instruments, appliances, etc., is printed on fine paper, and hand- somely bound in cloth.— Med. Record, Nov. 15,1882. It is fortunately not such an interminable trea- tise a< most electro-therapeutists like to write. It is not burdened with a needlessly learned terminol- ogy, and is written more from the point of view of the physician than the specialist. The second edi- tion has been considerably increased over the first, and has been brought up to the most recent ad- vances of the science. It can in every way be re- commended to those who wish to read a lucid, manageable monograph on this form of therapeu- tics.— Med. and Sura. Revorter. Nov. 4. 1882. MITCHELL [S. WEIR), M.D., J., S.. Phys. to Orthopaedic Hospital and the Infirmary for Pis. of the Nervous System, Phila., etc. etc. LECTURES ON DISEASES OF THE NERVOUS SYSTEM, ESPECIALLY IN WOMEN. Second Edition. In one very handsome 12mo. volume of about 250 pages. (Preparing.) The life-long devotion of the author to the subjects discussed in this volume has rendered it eminently desirable that the results of his labors should be embodied for the benefit of those who may experience the difficulties connected with the treatment of this class of disease. Many of these lectures are fresh studies of hysterical affections; others treat of the modifica tions his views have undergone in regard to certain forms of treatment, while, throughout the whole work he has been careful to keep in view the practical lessons of his cases. A few notices of the previous edition are appended :— It is a record of a number of very remarkable cases, with acute analyses and discussions, clinical, physiological and therapeutical It is a book to which the physician meeting wiih a new hysterical experience, or in doubt whether his new experience is hysterical, may well turn with a well-grounded hope of finding a parallelism; it will be a new ex- perience, indeed, if no similar one is here recorded —Phila. Med. Times, June 4, 1881. The book throughout is not only intensely enter- taining, but it contains a large amount of rare and valuable information. Dr. Mitchell has recorded not only the results of his most careful observation, but has added to the knowledge of the subjects treat- ed by his original investigation aud practical study. The book is one we can commend to all of our read- ers.—Maryland Med. Journal, May 1, 1881. fjA MIL TO A' (ALLAN Me LA NE), M. D., ■s Attending Physician at the. Hospital for Epileptics and Paralytics, Blackwell's Island, N. Y., and at the Out-Patients’ Department of the. New York Hospital. NERYOUSDISEASES;TIIEIR DESCRIPTION AND TREATMENT. Second Edition, thoroughly revised and rewritten. In one handsome octavo volume of 598 pages, with 72 illustrations. Cloth, $4. (Just Ready.) We are glad to welcome a second edition of so i useful a work as this, in which Dr. Hamilton has I succeeded in condensing into convenient limits the j most important of the recent developments in regard to diseases of ths nervous system. Of recent years nervous pafhology has attained to such importance i as to necessitate very careful description in special ! works, and among these this volume must take a high place. This volume is on the whole excellent, I and is devoid of that spirit of plagiarism which we I have unfortunately seen too much of in certain recent English works on nervous disease.—Edinburgh Med. Journal, May, 1882. When the first edition of this good book appeared we gave it our emphatic endorsement, and the pre- I sent edition enhances our appreciation of the book and its author, as a safe guide to students of clini- cal neurology. One of the best and most critical of English neurological journals, Brain, has charac terized this book as the best of its kind in any lan- guage, which is a handsome endorsement from an ! exalted source. The improvements in the new edi- : tion, and the additions to it, will justify its pur- chase even by those who possess the old.—Alienist and Neurologist, April, 1882. CLINICAL OBSERVATIONS ON FUNCTIONAL N ERVO US DISORDERS B y C. H andfie lb Jones, The author’s aim is to write a treatise on Nervous Di eases which is both concise and practical, while ! it is, at the same time, sufficiently comprehensive. We have pleasure in bearing testimony to the fact that his efforts have been crowned with success. | The various diseases have been well described, the | directions as to how to arrive at a correct diagnosis are very clear,and the hints in treatment are plain, | practical and sound. Such a book should be con- J sidered a necessity in e tery medical library, as the ailments described are among the most common j that come under observation in the every-day work of the general physician. To him, therefore, we recommend it with pleasure; in fact, we may go | further and say that, all things considered, it is fpr f his purpose the best work of the kind now avail- able.—Can. Journ Med. Sciences, April. 1S82. This work is well adapted to the wants of the general practitioner, for whom it seems to have been especially written. It is a thoroughly prac- i tical book, the careful study of which will render the diagnosis of nervous affections the more easy, and their treatment more successful. The book is very useful as a reference work to the busy prac- titioner, to whom we can commend it. — Med. arid I Surg. Reporter. Jan. 21, 1882. 1 M.D. Second American Edition. Inone handsome I octavo volume of 348 pages. Cloth, $3 25. Henry C. Lea’s Son & Co.’s Publications—(Dis.of the Skin, d»c.). 19 MORRIS (MALCOLM), M.D., Joint Lecturer on Dermatology, St. Mary's Hospital Med. School. SKIN DISEASES, Including their Definitions, Symptoms, Diagnosis, Prognosis, Morbid Anatomy and Treatment. A Manual for Students and Practitioners. In one 12mo. volume of over 300 pages, with illustrations. Cloth, $1 75. Jo physicians who would like to know something about skin diseases, so that when a patient presents himself for relief they cau make a correct diagnosis and prescribe a rational treatment, we unhesitatingly recommend this little book of Dr. Morris. The affec- tions of the skin are described in a terse, lucid man- ner. and their several characteristics so plainly set forth that diagnosis will be easy. The treatment in each case is such as the experience of the most eminent dermatologists advises.—Cincinnati Medi- cal News, April, 18S0. This is emphatically a learner’s book ; for we can safely say, so far as our judgment goes, that in the whole range of medical literature of a like scope’ there is no book which for clearness of expression, and methodical arrangement is better adapted to promote a rational conception of dermatology, a branch confessedly difficult and perplexing to the begianer.—St. Louis Courier of Medicine, April, 18S0. The author’s task has been well done and/haR pro- duced one of the best recent works upon the difficult subject of which ittreats. There is no work published which gives a better view of the elementary facts and principles of dermatology.—New Orleans Medi- cal and Surgical Journal, April, 1880. JJYDE (J. NEVINS), M.D.7 -*-A. Professor of Dermatology and Venereal Diseases in Rush Medical College, Chicago. A PRACTICAL TREATISE ON DISEASES OF THE SKIN. For the Use of Students and Practitioners In one handsome octavo volume of 570 pages, with 66 beautiful and elaborate illustrations. Cloth, $4 25; leather, $5 25. (Just Ready.) FOX ( TILBVRD. M.D., F.R.C.P.. and T. O. FOX. B.A., M.R.C.S., Physician to the Department for Skin Diseases, University College Hospital AN EPITOME OF SKIN DISEASES. WITH FORMULA]. For Students and Practitioners. Third Edition, specially revised by the Author, aDd greatly enlarged. In one very handsome 12mo. volume. (Preparing.) Jj7LINT (AUSTIN), M.D., Professor of the Principles and Practice of Medicine in Bellevue Hospital Med. College, N. T. A MANUAL OF AUSCULTATION AND PERCUSSION; of the Physical Diagnosis of Diseases of the Lungs and Heart, and of Thoracic Aneurism. Third Edition. In one handsome royal 12mo. volume. (Nearly Ready.) JJ T THE S A ME A UTIIOR PHYSICAL EXPLORATION OF THE LUNGS BY MEANS OF AUSCULTATION AND PERCUSSION, phia County Medical Society, 1882-1883. pages. Cloth, $1 00. (Just Ready.) Three lectures delivered before the Philadel- In one handsome small 12mo. volume of 83 JJT THE SAME AUTHOR. PHTHISIS: ITS MORBID ANATOMY, ETIOLOGY, SYMPTOM- ATIC EVENTS AND COMPLICATIONS, FATALITY AND PROGNOSIS, TREAT- MENT AND PHYSICAL DIAGNOSIS; in a series of Clinical Studies. By Austin Flint, M.D., Prof, of the Principles and Practice of Medicine in Bellevue Hospita l Med- ical College, New York. In one handsome octavo volume of 142 pages. Cloth, $3 50. JJT THE SAME AUTHOR. A PRACTICAL TREATISE ON THE DIAGNOSIS, PATHOLOGY AND TREATMENT OF DISEASES OF THE HEART. Second revised and enlarged Edition. In one octavo volume of 550 pages, with a plate. Cioth, $4. JOT THE SAME AUTHOR. A PRACTICAL TREATISE ON THE PHYSICAL EXPLORA- TION OF THE CHEST AND THE DIAGNOSIS OF DISEASES AFFECTING THE RESPIRATORY ORGANS. Second and Revised Edition. In one handsome octavo vol- ume of 591 pages. Cloth, $4 50. 'UROWNE (LENNOX), F.R.C.S. Ed., Senior Surgeon to the Central London Throat and Ear Hospital, etc. THE THROAT AND ITS DISEASES. Second American, from the Second English Edition, thoroughly revised. With one hundred typical illustrations in colors, and fifty wood engravings, designed and executed by the author. In one very handsome imperial octavo volume of about .350 pages. (Preparing. ) OE1LER {CARL), M.D., Lecturer on Laryngoscopy at the University of Pennsylvania, Chief of the Throat Dispen- sary at tht University Hospital, Philadelphia, etc. A HANDBOOK OF DIAGNOSIS AND TREATMENT OF DISEASES OF THE THROAT, NOSE AND NASO-PHARYNX. Second Edition. In one hand- some royal 12mo. vol. of about 150 pages, with about 50 illustrations. (Nearly Ready.) WILSON'S STUDENT’S BOOK OP CUTANEOUS MEDICINE and Diseases op the Skin. In one very handsome royal 12mo, volume. Cloth, $3 50. HILLIER’S HANDBOOK OP SKIN DISEASES, for Students and Practitioners. SeeoDd Am Ed. In one roval 12mo. vol. of 358 pp, with illustrations. Cloth, $2 25. 20 Henry C. Lea’s Son & Co.’s Publications—(Venereal Diseases, d?c.). PORNIL (V.). V' Professor to the Faculty of Medicine of Paris, and Physician to the Lourcine Hospital. SYPHILIS, ITS MORBID ANATOM DIAGNOSIS AND TREAT- MENT. Specially revised by the Author, and translated with notes and additions by J. Henry C. Simes, M.D., Demonstrator of Pathological Histology in the University of Penn- sylvania and Surgeon to the Episcopal Hospital, Philadelphia, and J. William White, M.D., Lecturer on Venereal Diseases and Demonstrator of Surgery in the University of Pennsylvania, and Surgeon to the Philadelphia Hospital In one handsome octavo volume of 461 pages, with 84 very beautiful illustrations. Cloth, $3 75. (Just Ready.) It is with the special purpose of showing the evo- lution of the disease as indicated by histological changes that the author has prepared this volume. In , his respect it is much better than any other we could name, and merits the close reading of -ypiii- lologists. The translation is well done, and the reader will not regret the considerable additions which the translators have inserted in the text.— Medical and Surgical Reporter, Ang. 5, 18S2. The original form of lectures has been changed into chapters in the present issue, and a large amount of additional matter has, with the consent of the author, been inserted by the translators. These interpolations deal mainly with the clinical aspects of the disease, and contain much valuable and well-digested material. Of the of re- searches contained in the present work, it is need- less to say that they are worthy of the high reputa- tion the author has gained in other branches of pathological anatomy. The volume differs in one respect from the many excellent treatises on the subject, which have appeared in Tecent years, both in this country, in France and in America, and sup- plies a deficiency in the bibliography of the affec- lion, by giving especial prominence to its minute anatomy. The microscopical sections were, as far as possible, made from portions of tissue removed dur- ing life, so as to eliminate appearances due to post- mortem change, and excellent drawings of the chief lesions are scattered throughout the volume. We cau strongly recommend the work to all who are interested in the study of the intimate pathology of syphilis.—London Med. Times and Gaz., Nov. 18, 18S2. The characteristic feature of M. Cornil’s work is the attention paid to the minute anatomy of the syphilitic lesions. The histological evolution of the various phases of the disease, from the initial chan- cre to the gumma, including the mucous patch, the superficial and deep cutaneous syphilides, the osse- ous and visceral affections—is considered with a de- tail that is in striking contrast to that of other works upon the same subject. The translation has been made wi h bis consent and approval, and he is for- tunate in the selection of his translators, for they have added materially to the interest aud value of the volume —Maryland Mtd. Journ., Aug. 15, 1882. Q UMSTEAD (F. J.), M.D., LL.D., Late Professor of Venereal Diseases at the Coll, of Phys. and Surg., New York, etc and /TAYLOR {R. W.), A.M.. M.D., Professor of Dermatology in the Uni- versity of Vermont; Attending Sur- geon to Charity Hospital, etc. THE PATHOLOGY AND TREATMENT OF VENEREAL DIS- EASES. Including the results of recent investigations upon the subject. Fifth Edition, revised and largely rewritten. In one large and handsome octavo volume of about 900 pages, with about 160 illustrations. (In Press.) A few notices of the previous edition are appended. We have to congratulate our countrymen upon the truly valuable addition which they have made to American literature. The careful estimate of the value of the volume, which we have made, justifies us in declaring that this is the best treatise on venereal diseases in the English language, and we might add, if there is a better in any other tongue we cannot name it; there are certainly no books in which the student or the general practitioner can find such an excellent risnmi of the literature of any topic, and such practical suggestions regarding the treatment of the various complications of every venereal disease. We take pleasure in repeating that we believe this to be the best treatise on vene- real disease iu the English language, and we con- gratulate the authors upon their brilliant addition to American medical literature.—Ohicago Med. Jour- nal and Examiner, February, 18S0. It is, without exception, the most valuable single work on all branches) of the subject of which it treats in any language. The pathology is sound, the work is, at the same time, in the highest degree practical, and the hints that the practitioner will get from it for the management of any one case, at all obscure or obstinate, will more than repay him for the out- lay.— Archives of Medicine, April, 1880. It is one of the best general treatises on venereal diseases with which we are acquainted, and is espe- cially to be recommended as a guide to the t reatment of syphilis.—London Practitioner, March, 1880. (AROSS (SAMUEL IF), A.M., M l).. YT Professor of the Principles of Surgery and. of Clinical Surgery in the. Jefferson Med. College, Phila. A PRACTICAL TREATISE ON IMPOTENCE, STERILITY, AND ALLIED DISORDERS OF THE MALE SEXUAL ORGANS. In one very hand- some octavo volume of 166 pages, with 16 illustrations. The author has devoted much time to the hardest study of this most trying class of diseases, and this labor, together with the fruit of laborious research into the scattered literature of the subject, consti- tutes the result of his investigations. We cau ear- nestly commend it to the practitioner as the very besi work upon the subject in the English language. —Nashville Journ. of Med. and Surg., Oct. 1S81. The author is a clear aud concise writer, and every page of this treatise gives evidence of his thorough familiarity with recent research, and with the latest journal literature. The book is a thoroughly scien- tific exposition of our present knowledge of the sub- jects treated of ; its pages are rich in information of high value to the practitioner, and once read, will be frequently referred to.—St. Louis Courier of Med., Nov. 1S81. (JULLERIER (A.), Surgeon to the Hdpital du Midi. and T? UMSTEAD (F. J.), MB., LL.D., J * late Prof essor of Venerea l Diseases in the Col- lege of Physicians and Surgeons, N. Y AN ATLAS OF VENEREAL DISEASES. Translated and Edited by Freeman J. Bumstead. In one large imperial 4to. volume of 328 pages, double-columns, with 26 plates, containing about 160 figures, beautifully colored, many of them the size of life. Strongly bound in cloth, $17 00 ; also, in five parts, stout wrappers, at $3 per part. A specimen of the plates and text sent free by mail, on receipt of 26 cents. LEE’S LECTURES ON SYP1IILTS AND SOME I FORMS OF LOCAL DISEASE AFFECTING PRIN- CIPALLY THE ORGANS OF GENERATION. In 1 one handsome octavo volume. Cloth, $2 25. HILL ON SYPHILIS AND LOCAL CONTAGIOUS DISORDERS. In one handsome octavo volume. Cloth, $3 25. Henry C. Lea’s Son & Co.’s Publications—(Dia. of Children, dec.). 21 jgMITH (J. LEWIS), M.D., Clinical Professor of Diseases of Children in the Bellevue Hospital Med. College, N.7. A COMPLETE PRACTICAL TREATISE ON THE DISEASES OF CHILDREN. Fifth Edition, thoroughly revised and rewritten. In one handsome oc- tavo volume of 836 pages, with illustrations. Cloth, $4 50; leather, $5 50; very hand- some half Russia, raised bands, $6. That a book professing to treat of diseases of chil- dren should have reached a fifth edition is iu itself fair evidence of 'ts worth, the more especially as it has not tlie field to itself, but has to compete with several other excellent manuals. The chapter on Rachitis is excellent, and well up to the day—a re- mark which may with equal justice be applied to the chapter on Scrofula, which is one of the best we remember to hare read. The diseases of the nervous system are well described, and so, for the most part, are those of the iung?. Dr. Smith would appear to be qui e au courant with the work done on this side of the world, and refers freely to English and foreign auth rs, as well as to periodicals especially devoted to children’s diseases.—British Medical Journal, May 6, 1882. Dr. Smith is a careful observer and painstaking writer. He has enjoyed unusual facilities which would en> hie him to write a practical and useful book, and that he has succeeded is attested by the appearance of successive editions of his work. There is no doubt bur. that it will long retain its place as a standard text-bo k among students and prac’ition- ers.—American Journal of Obstetrics, Jan. 18S2. There is no book published on the subjects of which this one treats that is its equal in value to the physician. While he has said just enough to impart the information desired by general practitioners on such questions as etiology, pathology, prognosis, etc., he has devoted more attention to the diagnosis and treatment of the ailments which ho so accu- rately describes, and such information is exactly what is wanted by the vast majority of ‘‘family physicians.”—Virginia Med. Monthly, Feb. 1882. The appearance of a fifth edition of this work is sufficient attestation of its great value to the prac- titioners of the country, and of the use they are disposed to make of it. Unquestionably it is the best work on the maladies of childhood in the Eng- lish language, and in any foreign language we knew of no work which will compare with it. That the fifth edition has been thoroughly revised and brought up to date an attentive (or even careless) perusal will abundantly disclose.—Canadian Jour- nal of Med. Science, Feb. 18S2. The improvements that have been added briDg the work fully abreast of the times. We can assure our readers that they can procure no better work on infancy and childhood for reference and study than this one.—Cincinnati Med. Ntios, Jan. 1882. TREATING [JOFIN M.), M.D., -*•*- Lecturer on the Diseases of Children at the University of Pennsylvania, etc. THE MOTHER’S GUIDE IN THE MANAGEMENT AND FEED- ING OF INFANTS. In one handsome 12mo. volume of 118 pages. Cloth, $1 00. The titleof this little book is well chosen, and Dr. Keating has written a work which should be read, and its precepts followed by every intelligent mo- ther in this country. It is free from all technical terms, the language is clear and distinct, and so carefully written that it cannot fail to become popu- lar. It has always been a mooted question how far it is well to instruct the public, but works like this one will aid the physician immensely, for it saves the time he is constantly giving his patients in in- structing them on the subjects here dwelt upon so thoroughly and practically. Dr. Keating has writ- ten a practical book, has carefully avoided unne- cessary repetition, and, I think, successfully in- structed the mother in such details of the treatment of her child as devolve upon her; he has studiously omitted giving prescriptions, and instrucis the mo- ther when to call upon the doctor, as his duties are totally distinct from hers.—American Journal of Obstetrics October 1S81. T> A MSB 0 THA M (FRANCIS H.), M.D THE PRINCIPLES AND PRACTICE OF OBSTETRIC MEDI- CINE AND SURGERY, in Reference to the Process of Parturition. A new and enlarged Edition, thoroughly revised by the author. With additions by W. V. Keating, M. D., Professor of Obstetrics, Ac., in the Jefferson Medical College, Philadelphia. In one large and handsome imperial octavo volume of 640 pages, with sixty-four beautiful plates, and numerous wood-cuts in the text, containing in all nearly 200 large and beautiful figures. Strongly bound in leather, with raised bands. $7 00 IXTEST [CHARLES). M.D., Physician to the Hospital for Sick Children, London, Ac. LECTURES ON THE DISEASES OF INFANCY AND CHILD- HOOD. Fifth American from the Sixth revised and enlarged English Edition. In one large and handsome octavo volume of 686 pages. Cloth, $4 50 ; leather, $5 50. fiY THE SAME AUTHOR ( Lately Issued.) ON SOME DISORDERS OF THE NERVOUS SYSTEM IN CHILD- HOOD ; being the Lumleian Lectures delivered at the Royal College of Physicians of London, in March, 1871. In one volume, small 12mo. Cloth, $1 00. ft Y THE SAME AUTHOR. LECTURES ON THE DISEASES OF WOMEN. Third American, from the Third London Edition. In one octavo volume of about 550 pages. Cloth, $3 75; leather, $4 75. TXTINCKEL (F.). V A COMPLETE TREATISE ON THE PATHOLOGY AND TREATMENT OF CHILDBED, for Students and Practitioners. Translated, with theconsent ofthe author,from the Second German Edition, by James Read Chadwick, M.D. Id one octavo volume of 484 pages. Cloth, $4 00. SMITH’S PRACTICAL TREATISE ON THE WAST- ING DISEASES OF INFANCY AND CHILDHOOD. Second American, from the Second English Edi- tion. In one octavo volume. Cloth, $2 SO. Henry C. Lea’s Son & Co.’s Publications—(Dis. of Women). 22 rpHOMAS (T. GAILLARD), M.D A Professor of Obstetrics, &c., in the College of Physicians and Surgeons, N. Y., &c A PRACTICAL TREATISE ON THE DISEASES OF WOMEN. Fifth Edition, thoroughly revised and rewritten. In one large and handsome octavo volume of 810 pages, with 266 illustrations. Cloth, $5; leather, $6; very handsome half Russia, raised bands, $6 50. The words which follow “fifth edition” are in this case no mere formal announcement. The alter- ations and additions which have been made are both numerous and important. The attraction and the permanent character of this book lie in the clear- ness and truth of the clinical descriptions of dis- eases ; the fertility of the author in therapeutic re- sources, and the fulness with which the details of treatment are described; the definite character of the teaching; and last, but not least, the evident candor which pervades it. We would also particu- larize the fulness with which the history of the sub- ject is gone into, which makes the book addition- ally interesting, and gives it value as a work of reference.—London Med. Times and Gaz., July 30, 1881. An examination of the work will prove that it is one of great merit. It is not a mere compilation from other works, but is the fruit of the ripe thought, sound judgment, and critical observations of a leirned, scientific man. it is a treasury of knowledge of the department of medicine to which it is devoted In its present revised state it cer- tainly holds a foremost position as a gynaecological work, and will continue to be regarded as a stan- dard authority.—Cincinnati Med. News, Dec. 18S0. This work needs no introduction to any of the civilized nations of the world. The edition before us adds to the strength of former volumes. With the wisdom of a master teacher he here gives the results that, in his judgment, are most trustworthy at the present time. In its own place it has no rival, because the author is the best teacher on this subject to the masses of the profession As hitherto this work will he the text-book on diseases of wo- men. We only wish that in other branches of medi- cine as capable teachers could be found to write our text-books.—Detroit Lancet, Jan. 1881. It has been enlarged and carefully revised. The author has brought it fully abreast with the times, and as the wave of gynaecological progression has been widespread and rapid during the twelve years that have elapsed since theissue of the first edition, one can conceive of the great improvement this edi- tion must be upon the earlier. It is a condensed en- cyclopaedia of gynaecological medicine. The style of arrangement, the masterly manner in which each subject is treated, and the honest convictions de- rived from probably the largest clinical experience in that specialty of any in this country, all serve to commend it in the highest terms to the practitioner. — Nashville Journ. of Med. and Surg., Jan. 1881. (GYNECOLOGICAL TRANSACTIONS. Vol. VI. Being the Transactions of the American Gynecological Society for the Year 18S1. VOLUME VI. (Just Ready) Contains Essays by Doctors W. H, By- ford, S. C. Busey, H. J. Garrigues, G. H. Lyman, Nathan Bozeman, E. Van de War- ker, I. E. Taylor, W. Goodell, II. F. Campbell, T. G. Thomas T. A. Reamy, A. H. Smith, A. D. Sinclair, J. W. Underhill, E. W. Jenks, LL.D., W. M. Polk, W. R.'Gillette, C. C. Lee, F. P. Foster, E. W. Sawyer and B. B. Browne. With Indexes: (a), of Vol. VI.; (5), of the Gynecological and Obstetric Literature of all Countries for the Year 1880; (c), of Obstetric and Gynecological Journals, and (d) of Obstetric and Gynecological Societies. The six volumes completing the series will be sent by mail postpaid on receipt of $30, or if single copies are desired they will be furnished at the rate of $5 each, excepting Vol. II. for the year 1877, the price of which is $6.50. JfDIS {ARTHUR W.), M.D. Lond., F.R. G.P., M R.G.S., Assist. Obstetric Physician to Middlesex Hospital, late Physician to British Lying-in Hospital. THE DISEASES OF WOMEN. Including their Pathology, Causa- tion, Symptoms, Diagnosis and Treatment. A manual for Students and Practitioners. In one handsome octavo volume of 576 pages, with 148 illust. Cloth, $3 ; leather, $4. It is a pleasure to read a book so thoroughly good as this one. The special qualities which are con- spicuous are thoroughness in covering the whole ground, clearness of description, and conciseness of statement. Another marked feature of the book is the attention paid to the deails of many minor sur- gical operationsand procedures, as, forinstance the use of tents, application of leeches, and use of hot- water injections. These are among the more com- mon methods of treatment, and yet very little is said about them in many of the text-books. The hook is one to be warmly recommended, especially to students and general practitioners, who need a con- cise but complete risume of the whole subject. Spe- cialists, too, will find many useful hints in its pages. —Boston Med and Surg. Journ., March 2, 1882. The greatest pains have been taken with the sec- tions relating to treatment. A liberal selection of remedies is given for each morbid condition, the strength, mode of application, and other details being fully explained. The descriptions of gynteco- logical manioula tions and operations are full, clear, and practical. Much care lias also been bestowed on the parts of the book which deal with diagnosis : we note especially the pages dealing with the dif- ferentiation, one from another of the different binds of abdominal tumors. The practitioner will there- fore find in this book the kind of knowledge be most needs in his daily work, and he will be pleased w th the clearness and fulness of the information there given.— The Practitioner, Feb. 18S2. DARNES [ROBERT), M.D., F.R.C.P., Obstetric Physician to St. Thomas' Hospital, &c. A CLINICAL EXPOSITION OF THE MEDICAL AND SURGI- CAL DISEASES OF WOMEN. In one handsome octavo volume, with numerous illustrations. (New Edition Preparing.) TJODGE {HUGH L.), M.D., •*-*- Emeritus Professor of Obstetrics, Sec., in the University of Pennsylvania. ON DISEASES PECULIAR TO WOMEN; including Displacements of the Uterus. Second Edition, revised and enlarged. Id one beautifully printed octavo volume of 519 pages, with original illustrations. Cloth, $4 50. Henry C. Lea’s Son & Co.’s Publications—(Dis.of Women'). JAM ME T (THOMAS ADDIS), M.D., LED., Surgeon to the Woman's Hospital, New York, etc. THE PRINCIPLES AND PRACTICE OF for the use of Students and Practitioners of Medicine. Second Edition. Thoroughly Revised. In one large and very handsome octavo volume of 879 pages, with 133 illustrations. Cloth, $5; leather, $6; half Russia, raised hands, $6 50. In no country of the world has gynecology re- ceived more attention thanin America. It is, then, with a feeling of pleasure that we welcome a work on diseases of women from so eminent a gynecolo gist as Dr. Emmet. The work is essentially clini- cal, and leaves a strong impress of the author’s in- dividuality. To criticize, with the care it merits, the book throughout, would demand far more space than is at our command. In parting, we can say that the work teems with original ideas, fresh and valuable methods of practice, and is written in a clear and elegant style, worthy of the literary repu- tation of the country of Longfellow and Oliver Wen- dell Holmes.—Brit. Med. Journ. Feb 21,18S0. No gynecological treatise has appeared which contains an equal amount of original and useful matter; nor does the medical and surgical history of America include a book mor» novel and useful. The tabular and statistical information which it contains is marvellous, both in quantity and accu- racy, and cannot be otherwise than invaluable to future investigators. It is a work which demands not careless reading but profound study. Its value as a contribution o gynecology is, perhaps,greater than that of ail previous literature on the subject combined.—Chicago Med. Gaz., April t, 1S80 The wide reputation of the author makes itspub- lication an event in the gynaecological world ; and a glance through its pages shows that it is a work to be studied with care. ... It must always be a work to be carefully studied and frequently con- sulted by those who practise this branch of our pro- fession.— Lond. Med. Times and Gaz., Jan. 10,1880. The character of the work is too well known to require extended notice—suffice it to say that no recent work upou any subject has attained such great popularity so rapidly. As a work of general reference upon the subject of Diseases of Women it is invaluable. As a record of the largest clinical experience and observation it has no equal. No physician who pretends to keep up with the ad- vances of this department of medicine can afford to be without it.—Nashville Journ. of Medicine and Surgery, May, 1880. AMERICAN SYSTEM OE GYNAECOLOGY. A SYSTEM OF GYNAECOLOGY IN TREATISES BY VARIOUS AUTHORS. (In Active, Preparation.) n UNCAN (J. MATTHEWS), M.D., LL.D., F.R.S.E., etc. CLINICAL LECTURES ON THE DISEASES OF WOMEN, Delivered in Saint Bartholomew’s Hospital. In one handsome octavo volume of 175 pages. Cloth, $1 50. They are in every way worthy of their author ; Indeed, we look upon them as among tbe most valu- able of his contributions. They are ail upon mat- ters of great interest to the general practitioner Some of them deal with subjects that are not, as a rule, handled in the text-books; others of them, while bearing upon topics that are usually treated of at length in such works, yet bear such a stamp of individuality that, if widely read, as they certainly deserve to be, they cannot fail to exert a wholesome restraint upon the undue eagerness with which many yonng physicians seem bent npon fol- lowing the wild teachings which so infest the gyne- cology of the present day.—N. Y. Med. Journ., March, 1880. PARRY (JOHN S.), M.V., Obstetrician to the Philadelphia Hospital, Vice-Prest. of the, Ohstet. Society of Philadelphia EXTRA-UTERINE PREGNANCY: ITS CLINICAL HISTORY, DIAGNOSIS, PROGNOSIS AND TREATMENT. In one handsome octavo volume of 272 pages. Cloth, $2 50. J1ANNER ( THOMAS //.), M.D. ON THE SIGNS AND DISEASES OF PREGNANCY. First American from the Second and Enlarged English Edition. With four colored plates and illustra- tions on wood. In one handsome octavo volume of about 500 pages. Cloth, $4 25. fVUSSEROW [A.), Professor of Midwifery and the Diseases of Children at the University of Berlin. A PRACTICAL TREATISE ON UTERINE TUMORS. Specially revised by the Author, and translated with Notes and Additions by Edmund C. Wendt, M D., Pathologist to the St. Francis Hospital, N. Y., etc., and revised by Nathan Bozeman, M.D., Surgeon to the Woman’s Hospital of the State of New York. In one handsome octavo volume, with about 40 illustrations. (Preparing.) nnADWICK (JAMES R.), A.M., M.D. MANUAL OF THE DISEASES PECULIAR TO WOMEN. In one handsome royal 12mo. volume, with illustrations. (Preparing.) ASHWELL’S PRACTICAL TREATISE ON THE DIS EASES PECULIAR TO WOMEN. Third American from the Third and revised London Edition. In one 8vo. vo’., pp 528. Cloth, $3 50. CON DIE’S PRACTICAL TREATISE ON THE DIS- EASES OF CHILDREN. Sixth Edition, revised and augmented. In one large octavo volume o nearly 8f0 closely-printed pages Cloth, $5 25 : leather $6 25. JHURCHILL ON THE PUERPERAL FEVER AND OTHER DISEASES PECULIAR TO WOMEN. In one octavo volume of 450 pages. Cloth, $2 50. MEIGS ON THE NATURE, SIGNS AND TREAT MENT OF CHILDBED FEVER In one 8vo. vol. pp. 346. Cloth, $2 00. MONTGOMERY’S EXPOSITION OF THE SIGNS AND SYMPTOMS OF PREGNANCY. With two exquisite colored plates, and numerous wood cuts. In one vol. 8vo.,of nearly 600pp. Cloth,$3 75. 24 Henry C. Lea’s Son & Co.’s Publications—(Midwifery). J EISHMAN ( WILLIAM). M.D., Regius Professor of Midwifery in the University of Glasgow, Ac. A SYSTEM OF MIDWIFERY, INCLUDING THE DISEASES OF PREGNANCY AND THE PUERPERAL ST ATE. Third American Edition, revised by the Author, with additions hy John S. Parry, M.D., Obstetrician to the Philadelphia Hospital, &c. In one large and very handsome octavo volume, of 740 pages, with 205 illustrations. Cloth, $4 50 ; leather, $5 50 ; half Russia, $6. Few works on this subject have met with as great a demand as this one appears to have. To judge by the frequency with which its author’s views are quoted, and its statements referred to in obstetrical literature, one would judge that there are fewphy- siciaus devoting much attention to obstetrics who are without it. The author is evidently a man of ripe experience and conservative views, and in no branch of medicine are these more valuable than in this.—New Remedies, Jan. 1880. We gladly welcome the new edition of this excel- lent text-book of midwifery. The former editions have been most favorably received by the profes- sion on both sides of the Atlantic In the prepara- tion of the present edition the author has made.such alterations as the progress of obstetric rl science seems to require, and we cannot but admire the ability with which the task has been performed. We consider it an admirable text-book for students duriug their attendance upon lectures, and have great pleasure in recommending it. As an exponent of the midwifery of the present day it has no supe- rior in the English language.—Canada Lancet, Jan. 1880. To the American student the work before us must prove admirably adapted, complete in all its parts, essentially modern in its teachings and with dem- onstrations noted for clearness and precision, it will gain in favor and be recognized as a work of stand- ; ard merit. The work cannot fail to be popular, and ; is cordially recommended.—N. 0. Med. and Surg. Journ., March, 1S80. PLAYFAIR ( W. S.), M.D., F.R.C.P., Professor of Obstetric Medicine in King's College,etc. etc. A TREATISE ON THE SCIENCE AND PRACTICE OF MIDWIFERY. Third American Edition, revised by the author. Edited, with additions, by Robert P. Harris, M.D. In one handsome octavo volume of 659 pages, with 183 illustrations. Cloth, $4 ; leather, $5 ; half Russia, $5 50. The medical profession has now the opportunity of adding to their stock of standard medical works one of the best volumes on midwifery ever published. The subject is taken up with a master hand. The part devoted to laborin all its various presentations, the management and results, is admirably arranged, and the views entertained will he fouud essentially modern, and the opinions expressed trustworthy. The work abounds with plates, illustrating various obstetrical positions ; they are admirably wrought, and afford great assistance to the student.—N. O. Med. and Surg. Journ., March, 1880. The rapidity with which one edition of this work follows another is proof alike of its excellence and of the estimate that the profession has formed of it. It is indeed so well known and so highly valued that nothing need be said of it as a whole. All things considered, we regard this treatise as the very- best on Midwifery in the English language.—N. Y. Medical Journal,, May, 1880. It certainly is an admirable exposition of the Science and Practice of Midwifery. Of course the additions made by the American editor, Dr. R. P. Harris, who never utters an idle word, and whose studious researches in some special departments of obstetrics are so well known to the profession, are of great value.—The American Practitioner, April, 1880. JOY THE H A ME AUTHOR. THE SYSTEMATIC TREATMENT OF NERYE PROSTRATION AND HYSTERIA. In one handsome small 12mo. volume, of 97 pages. Cloth, $1 00. (Just Issued ) JZING (A. F. A.), M.D., ' Professor of Obstetrics and D 'senses of Women in the Medical Department of the Columbian University, Washington, D.C., and in the University of Vermont, &c. A MANUAL OF OBSTETRICS. In one very handsome 12mo. vol- ume of 321 pages, with 58 illustrations. Cloth, $2. (Just Ready.) Though the book appears small externally, it | contains as complete a consideration of obstetric ! subjects as many larger volumes, and this is chiefly ! owing to a directness of expression, and an avoid- ance of repetition, and of waste of words. The au- j thor endeavors to place theories, causes of disease, ! and. methods of treatment in that order which, by 1 weight of authority, they merit. His excellent j judgment has availed him well in this effort. While, jn one sense, the book is an excellent obstetric die- ' tionavy, and well suited to the student, it is also of value to the general practitioner, who often desires to find a risumk of information upon a given subject. It will be of farther value to the latter, as, in our opinion, the author holds most sensible views on practical matters. The book is admirably ar- ranged for reference, being well paragraphed, with suitable subdivisions, and well indexed.—American Journal of Obstetrics, Aug. 1882. pARVIN (THEOPHILUS), M.D. LL.D , ■-*- Prof, of Obstetrics and of the Med. and Surg. Diseases of Women in the Med. Coll, of Indiana. A TREATISE ON MIDWIFERY. In one very handsome octavo volume of about 550 pages, with numerous illustrations. (Preparing.) TDARNES [FANCOURT), M.D., Physician to the Genera l Dying-in Hospital, London. A MANUAL OF MIDWIFERY FOR MIDWIFES AND MEDICAL STUDENTS. With 50 illustrations. In one royal 12mo. volume of 200 pages. Cloth, $1 25. (Lately Issued.) fFODG-E (HUGH L.). 31.D., **-“• Emeritus Professor of Midwifery, Sec., in the University of Pennsylvania, Ac. THE PRINCIPLES ANI) PRACTICE OF OBSTETRICS. Illus- trated with large lithographic plates containing one hundred and fifty-nine figures from original photographs, and with numerous wood-cuts. In one large and beautifully printed quarto volume of 550 double-columned pages. Strongly bound in cloth, $14. Specimens of the plates and letter-press will be forwarded to any address, free by mail, on receipt of six cents in postage stamps. Henry C. Lea’s Son & Co.’s Publications—{Surgery). 25 LJAMILTON {FRANK H.), M.D., LL.D., a A Surgeon to the Bellevue Hospital, New York. A PRACTICAL TREATISE ON FRACTURES AND DISLOCA- TIONS Sixth Edition, thoroughly revised, and much improved. In one very handsome octavo volume of 909 pages, with 352 illustrations. Cloth, $5 50; leather, $6 50; half Russia, raised hands, $7 00. (Just Issued.) So many kind expressions ot welcome have been showered upon each successive edi iou of this val- uable treatise, that scarcely anything remains for ns to do hut to extend the customary cordial greet- ing. It is the only complete work on the subject of Fractures in the English language. We con- gratulate the accomplished author on the deserved success of his work and hope that he may live to liavemanv succe- dingeditions pas- underhis skilled supervision. — Coll, and Clin Rec., Nov. 15, 1880. Universal verdict has pronounced it, humanly speaking, a perfect treatise upon this subject. As it is the only complete and illustrated work in any language trea tiug of fracture? and dislocations, it is safe to ; ffivm that every wide-awake surgeon and general practitioner will regard it as indispensable tw the safe and pleasant conduct of their profes- sional work. — Detroit Lancet, Nov. 18, 1880. Dr Hamilton has devoted great tabor to the study of these subjects. His large experience, extended research, and patient investigation have made him one of the highest authorities among living writers in this branch of surgery This work is systematic and practical in its arrangement, and presents its subject matter clearly and forcibly to the reader or student.—Maryland Med. Journ., Nov. 15,1880. The only complete work on its subjectin the Eus- lish tongue, and, indeed, may now be said to be the only work of its kind in any tongue. It would require an exceedingly critical examination to de- tect in it any particulars in which it might be im- proved. The work is a monument to American surgery, and will long serve to keep green the memory of its venerable author.— Michigan Med. News, Nov. 10, 18S1. A SHHURST {JOHN, Jr.), 31.B., ■AA- Prof, of Clmical Surgery, Unix, of Pa., Surgeon to the Episcopal Hospital, Philadelphiai. THE PRINCIPLES AND PRACTICE OF SURGERY. Third Edition, enlarged and revised. In one very large and handsome octavo volume of 1060 pages, with 555 illustrations. Cloth, |6”; leather, $7 ; very handsome half Russia, raised bands, $7 50. (Just Ready.) The author, long known as a thorough student of surgery, and one of the most accomplished scholars in the country, aim3 to give in this work “a con- densed but comprehensive description of the modes of practice now generally employed in the treatment of surgical affections, with a plain exposition of the principles upon which these modes of practice are based.” In this he has so well succeeded that it will he a surprise to the reader to know how much practical knowledge extending over such a wide range of research is compressed in a volume of this size This feature of the work must be its best claim for continued popularity with students and practitioners. In fact, in this respect it is with- out any equal in any language. In the present edi- tion many novelties in surgical practice are intro- duced, many modifications of previous statements made, and several new illustrations added.—Med. Record, Nov. 18, 1882. A good student’s book, thoroughly reliable, brief, and to the point, abundantly illustrated. The posi- tion in medical literature of Ashhurst’s Surgery needs only the announcement of the appearance of a new edition without an extending notice of its peculiar merits.-— CjVegeand Clinical Record, Nov. 15, 18S2, /JOBERTS [JOHN 11), A.M., 31.D., A-*/ Lecturer on Anatomy avd on Operative Surgery at the Philadelphia School of Anatomy, Fellow of the PMlstAelphia Academy of Surgery. etc. THE PRINCIPLES AND PRACTICE OF SURGERY. For the Use of Students and Praetitioners of Medicine and Surgery. In one very handsome octavo volume of about 500 pages, with many illustrations. (Preparing.) & TIMS ON (LEWIS A.), B.A., M.I).. A-J Professor of Pathological Anatomy at the University of the City of New York, Surgeon and Cura- tor to BeHevue Hospital, Surgeon to the Presbyterian Hospital, New York, etc. A PRACTICAL TREATISE ON FRACTURES. In one very hand- some octavo volume of 582 pages, with 360 beautiful illustrations. Cloth, $4 75 ; leather, $5 75. (Just Ready.) This practical treatise upon the subject of frac- tures of the various portions of the boDy skeleton is a compendious exposition of the most recent as well as the best attested modes of treatment; but is not confined to this, as it also considers tiie pathology, etiology and mechanical principles involved in the different forms of fracture as well as the cause of delayed union, pseudo-arthrosis and other related topics. We have no criticism, hut only commenda tion, for this excellent work.—College and Clinical Record, Jan. 15, 1883. In examining the work one is impressed with the conciseness and propriety of the diction. The best views and the best practice of the best men are comprehensively and concisely massed. The judg- ment, extensive reading and extensive experience everywhere manifested are very welcome and valu- able. As a treatise on fractures it is a complete success, and it is issued in a manner thoroughly commensurate with its merits.—Ameiican Medical Weekly, Jan. 6, 1S8;>. ft Y THE SAME AUTHOR. A MANUAL OF OPERATIVE SURGERY. In one very handsome royal 12mo. volume of about 500 pages, with 332 illustrations ; cloth, $2 50. The work before us is a well printed, profusely Illustrated manual. The novice, by a perusal of the work, will gain a good idea of the general domain of operative surgery, while the practical surgeon has presented to him within a very concise and intelli- gible form the latest and mostapproved selections of operative procedure. Theprecision and conciseness ; with which the different operations are described , enable the author to compress an immense amount of practical information in a very small compass.— TV. Y. Medical Record, Aug. 3,1878. This volume is devoted entirely to operative sur-: gery, and is intended to familiarize the student with ; the details of operations and the different modes of performing them. The work is handsomely illus- trated, and the descriptions are clear and well drawn. It is a clever and useful volume; every student should possess one. The preparation of this work does away with the necessity of pondering over larger works on surgery for descriptions of opera- tions, asit presents in a nut-shell just whatis wanted by the surgeon without an elaborate search to find it.—Md. Med Journal, Aug. 1878. The author’s conciseness and the repleteness of the work with valuable illustrations entitle it to be classed with the text-books for students of operative surgery, and as one of reference for the practitioner. —Cincinnati Lancet and Clinic, July 27,1878. 26 Henry C. Lea’s Son & Co.’s Publications—{Surgery). SIR OSS (SAMUEL D.), M.D., LL.D., D.C.L., Oxon., LL.D., Cantab. La Emeritus Professor o f Surgery in the Jefferson Medical College of Philadelphia A SYSTEM OF SURGERY: Pathological, Diagnostic, Therapeutic and Operative Sixth Edition, greatly enlarged and thoroughly revised by the Author and Samuel W. Gross, A.M., M.D., Professor of the Principles of Surgery and of Clini- cal Surgery in the Jefferson Medical College. In two large and beautifully printed impe- rial octavo volumes containing 2382 pages, illustrated by 1623 engravings Strongly bound in leather, raised bands, $ 1 5; half Russia, raised bands, $16. (Just Ready ) Extract from Preface to the Sixth Edition. The object of this work, as set forth in the first edition, issued in 1859, is to fu>nish a sys- tematic and comprehensive treatise on the art and science of surgery, considered in the broad- est sense; one that shall serve the practitioner as a faithful and available guide in his daily routine of duty. My aim has been to embrace the whole domain of surgery, and to allot to every subject its legitimate claim to notice in the great family of external diseases and acci- dents. Special attention has also been bestowed upon the discrimination of diseases; and an elaborate chapter on general diagnosis has been introduced. Upon the edition now issued much time and labor have been expanded, rendered necessary by the astonishing progress made during the last ten years in every branch of surgery. Every chapter has been thoroughly revised, many portions have been entirely rewritten, and a large amount of new matter has been introduced, in order to place the work fully abreast of the existing state of our knowledge. The v-ork as a whole needs no commendation. Many years ago it earned for itseif the enviable re- putation of the leading American work on surgery, and it is still capable of maintaining that standard. The reason for iliis need only to be mentioned to be appreciated. The author has always been calm and jnuicious in his statements, has based his conclu- sions on much study and personal experience, lias been able to grasp bis subject in its entirely, and, above all, ha s consciei tiously adhered to truth and fact, weighing the evidence, pro and con, accoid- ingly. A considerable amount of new material has been introduced, and altogether the distinguished author i:as reason to be satisfied that he has placed the work fully abreast of the state of our knowl- edge.—Medical Record, Nov. 18, 18S2. This great work by Professor Gross is undoubt- edly the most magnificent work upon surgery in the English language It is a treatise upon surgery that is really encyclopaedic in its c! aracter as re- gards fully treating every topic of the science, and minutely detailing all tint is known in regard to it. There is scarcely a department to which he has not either added something, or elucidated better that which was already kuown. Without stopping to record actual discoveries we can truly say that his learning, experience and research, more than that of almost auy other great surgeon, has elevated sur- gery to the high pinnacle which it lias attained. In the sixth edition of this great work every chapter has been thoroughly revised, many portions have been entirely rewritfen and a large amount of new matter has been introduced in order to place the work fully abreast of the existing state of our knowledge.— Cincinnati Med. News, Nov. 18S2. UY THE SAME AUTHOR. A PRACTICAL TREATISE ON THE DISEASES, INJURIES and Malformations of the Urinary Bladder, the Prostate Gland and the Urethra. Third Edition, thoroughly revised and much condensed, by Samuel W. Gross, M.D., Sur- geon to the Philadelphia Hospital. In one handsome octavo volume of 574 pages, with 170 illustrations. Cloth, $4.50. For referenceandgeneral information, the physician or surgeon can find no work that meets their necessities i more thoroughly than this, a revised edition of an ex- cellent treatise, and no medical library should be with- out it. Replete with handsome illustrations and good t ideas, it has the unusual advantage of being easilj 5omprehended,by the reasonableand practical manner iu which the various subjects are systematized and arranged We heartily recommend it to the profession ts a valuableaddition to theimportant literature of dis- eases of the urinary organs.—Atlanta Med.Journ., Oct. 1876. 1>Y the same author. A PRACTICAL TREATISE ON FOREIGN BODIES IN THE AIR-PASSAGES. In 1 vol. 8vo., with illustrations, pp. 452. Cloth, $2 75. (lOLEMAN [ALFRED), L.R.C.P., F.R.G.S., Exam. L.D.S., etc. Senior Dental Surgeon and Lecturer on Dental Surgery to St. Bartholomew s Hospital and the Dental College of London. A MANUAL OF DENTAL SURGERY AND PATHOLOGY. Thoroughly revised and adapted to the use of American students, by Thomas C. Stell- wttgen, M.A., M.D., D.D.S., Prof, of Physiology at the Philadelphia. Dental College. In one handsome volume of 412 pages, with 331 illustrations. Cloth, $3 25. (Just Ready.) This volume presents a highly creditable appear- ance, and deserves to rank among the most important of recent contributions to dental literature. Mr. Coleman has presented his methods of practice, for the most part, in a plain and concise manner, and the work of the American editor has been conscien- tiously performed. He has evidently labored to pre- sent his convictions of the best modes of practice lor the instruction of those commencing a professional career, and he has faithfully endeavored to teach to others all that he has acquired by his own ob erva- tion and experience, f he book deserves a place in the library of every dentist.—Denial Cosmos, May, 1882 The author brings to his task a large experience acquired under the most favorable circumstances. There have been added to the volume a hundred pages by the American editor, embedying the views of the leading home teachers in dental surgery. The work, therefore may be regarded as strictly abreast with the times, and as a very high authority on the subject of which it treats.—Amer. Prae., July, 18S2. It should be in the possession of every practitioner in this country. The part devoted to first and second dentition and irregularities in the permanent teeth is fully worth the price. In fact, price should not be considered in purchasing such a work. If the money put into some of our su-colted standard text- books could be converted into such publications as this, much good would result.— Southern Dental Journal, May, 1882. SCROFULA AND ITS GLANI) DISEASES. NJ an Introduction to the General Pathology of Scrofula, with an Account of the Histology, Diagnosis and Treatment of its Glandular Affections. By Fred- erick Treves, F.R.C.S. Eng., Assistant Surgeon to and Senior Demonstrator of Anatomy at the London Hospital. Complete in one octavo volume, in paper covers. Price, 10 cents. Henry C. Lea’s Son & Co.’s Publications—[Surgery). HOLMES (TIMOTHY), M. A., Surgeon and Lecturer on Surgery at St. George's Hospital, London. A SYSTEM OF SURGERY; THEORETICAL AND PRACTICAL. In Treatises by various authors. American Edition, Thoroughly revised and re-edited by John II Packard, M.D., Surgeon to the Episcopal and St. Joseph’s Hospi- tals, Philadelphia, assisted by a large corps of the most eminent American surgeons. In three large and very handsome imperial octavo volumes containing 3137 double-columned pages, with 979 illustrations on wood and thirteen lithographic plates, beautifully colored. Price per volume, cloth, $6 00 ; leather, $7 00 ; half Russia, $7 50. Per set, cloth, $18 00 ; leather, $21 00; half Russia, $22 50. (Sold only by subscription.) Volume I. (now ready) contains General Pathology, Morbid Processes, Injuries in General, Complications of Injuries and Injuries of Regions. Volume II. (now ready) contains Diseases of Organs of Special Sense, Circulatory System, Digestive Tract and Genito-urinary Organs. Volume III. (just ready) contains Diseases of the Respiratory Organs, Bones, Joints and Muscles, Diseases of the Nervous System, Gunshot Wounds, Operative and Minor Surgery, and Miscellaneous Subjects (including an essay on Hospitals). This great work, issued some years since in England, has won such universal confidence whereve” the language is spoken, that its republication here, in a form more thoroughly adapted to the wants of the American practitioner, has seemed to be a duty owing to the pro- fession. To accomplish this, the aid has been invited of thirty-three of the most distinguished gentle- men, in every part of the country, and for more than a year they have been assiduously engaged upon the task. Each article has been placed in the hands of a gentleman specially competent to treat its subject, and no labor has been spared to bring each one up to the foremost level of the times, and to adapt it thoroughly to the practice of the country. In certain cases, this has rendered necessary the substitution of an entirely new essay for the original, as in the case of the articles on Skin Diseases, and on Diseases of the Absorbent System, where the views of the authors have been superseded by the advance of medical science, and new articles have therefore been prepared by Drs. Arthur Van Harlingen and S. C. Busey. respectively. So also in the case of Anaesthetics, in the use of which American practice differs from that of Eng- land, the original has been supplemented with a new essay by J. C. Reeve, M.D., treating not only of the employment of ether and chloroform, but of the other anaesthetic agents of more recent discovery. The same careful and conscientious revision has been pursued through- out, leading to an increase of nearly one-fourth in matter, while the series of illustrations has been nearly trebled, and the whole is presented as a complete exponent of British and Ameri- can Surgery, adapted to the daily needs of the working practitioner In order to bring it within the reach of every member of the profession, the five volumes of the original have been compressed into three, by employing a double-columned imperial octavo page, and in this improved form it is offered at less than one half the price of the original. It is beautifully printed on handsome laid paper and forms a worthy companion to Reynolds’ System of Medicine, which has met with so much favor in every section of the country. The work will be sold by subscription only, and in due time every member of the profession will be called unon and offered an opportunity to subscribe. of Medicine”—will well represent the present state of ottr science. One wlio is larniliar with those two works will be fairly well furnished head-wise and hand-wise.— The .Medical News, Jan. 7, 1882. Great credit is due to the American editor and his co-laborers for revising and bringing within easy reach of American surgeons, a work wnich has been received with such universal (avoron the other side of the Atlantic as Holmes’ System of Surgery. In the list of English contributors to the first volume, we find the names of such well-known surgeons as Sir James Paget, Simon, Savory, Cailender, Barclay and others equally distinguished ; while among the American revisers we recognize men of no less celeb- rity. With regard to the mechanical execution of the work, neither pains nor money seem to have been spared by the publishers. — Med. and Surg. Reporter, Sept. 14, 1881. In the revision of the work for the American edi- tion, not only has provision been made for a recog- nition of the advances made in our knowledge dur- ing the ten years since its first publication, but also for a presentation of tbe variations in practice which characterize American surgery, and distinguish it from that of Great Britain. The work is one which we take plea ure in commending to the notice of our readers as an encyclopedia of surgical knowledge and practice.—St. Louis Ouuri r of Medicine, Nov. 1881. It is a subject for congratulation that the idea of an American edition. incorporating all recently ac- quired knowledgeand experience, should have been conceived, and its execution intrusted to such able hands as Packard’s. The names of coadjutors in the edition of the 1st volume, which has come to hand, afford a sufficient guarantee that the wor k has not only been brought folly up to date, but also that it has been accomplished in that large, thorough, and scientific spirit which characterized the contri- butions to the original edition.—Can. Journ. of Med. Science, Nov. 1SS1. The authors of the original English edition are men of the front rank in England, and Dr. Packard has been fortunate in securing as his American co- adjutors such men as Bartholow, Hyde, Hunt, Con- ner, Stimson, Morton, Hodgen, Jewell and their colleagues. They have revised and added to all the articles except three, which were found so complete as not to require any additions. The new matter varies considerably in amount and character, but is always judicious and useful. In some cases it is very slight, while in others the additions are large in amount and radical in character. As a whole, the work, if we may judge by this first volume, will be solid and substantial, and a valuable addition to the library of any medical man. It is more wieldy and more useful than the five volume English edition; and with its companion work—“Reynolds’ System nR UITT (ROBER T), M. R. C.S., frc. THE PRINCIPLES AND PRACTICE OF MODERN SURGERY. A new and revised American, from the Eighth enlarged and improved London Edition. Illus - trated with four hundred and thirty-two wood engravings. In one very handsome octawo volume, of nearly 700 large and closely printed pages. Cloth, $4 00 ■ leather, $5 00. MILLER’S PRINCIPLESOF SURGERY. Fourth Arne rican, from the Third Edinburgh Edition. In one large 8vo. vol. of 700pages, with 340 illustrations. Cloth, $3 76. MILLER’S PRACTICE OF SURGERY. Fourth Ame- rican, from the last Edinburgh Edition Revised by the American editor. In onelarge 8vo.vol.of nearly 700pages, with 364 illustrations. Cloth, $3 76. 28 Henry C. Lea’s Son & Co.’s Publications—[Surgery). URYA NT ( THOM A S), F.R. C.S., -*-* Surgeon to Guy's Hospital. THE PRACTICE OF SURGERY. Third American, from the Third and Revised English Edition. Thoroughly revised and much improved, by John B. Roberts, A.M., M.D. In one large and very handsome imperial octavo volume of 1009 pages, with 735 illustrations. Cloth, $6 50; leather, $7 50 ; very handsome half Russia, raised bands, $8 00. Mr. Bryant's work has long been a favorite one with surgeons. As its name indicates, it is of a tho- roughly practical character. It is distinctly indi- vidual in that it gives the results of the author’s large and varied experience as an operator and cli- nical teacher, ard is on that account prized deserv- edly high as an original work. The style is neces- sarily condensed, the descriptions of surgical dis- eases brief and to the point. The illustrations are well chosen, and the typical cases of the author’s experience are full of interest, and are of more than ordinary value to the working surgeon.—N. Y. Medical Record, March 5, 1881. It is a work especially adapted to the wants of students and practitioners. While not prolix, it affords instruction in sufficient detail for a full un- derstanding of surgical principles and the treat- ment of surgical diseases. ,It embraces in its scope all ihe diseases that are recognized as belonging to surgery, and all traumatic injuries. In discussing these H has seemed to be the aim of the author rather to present the student with practical infor- mation. a... d that alone, than to burden his memory with the views of different writers, however dis languished they might have been. In this edition the whole work has been carefully revised, much of it has been rewritten, and important additions have been made to almost every chapter.—Cincinnati Med. News, Jan. 18S1. The English edition, from which this is printed, has been carefully revised and rewritten; almost every chapter has received additions, and nearly one hundred new cuts introduced. The labors of the American editor, Dr. John B Roberts, have very mnch increased the value of the hook. He has introduced many new illustrations and much new material not found in the English edition. He has written, too, with great conciseness, which is a rare virtue in an American editor of an English work. If one could procure or wished only one surgery, this volume would certainly be selected. If he desired two, Erichien’s Surgery would he added, and if he wished a third, Gross’ Surgery would justly be the work selected. As the great work of Gross is amply sufficient for the wants of any surgeon, the priority given to Erich sen, and above all others, to this work of Bryant, is no labored eulogy of the last vol ujne, but a simple and j ust statement of its demonstrable and pre-eminent merits.—Am. Med. Bi-Weekly, Feb. 26, 1881. I? RICH SEN (JOHN E.), F.R.S., F.R.C.S. AJ Professor of Surgery in University College, London, etc. THE SCIENCE AND ART OF SURGERY ; being a Treatise on Sur- gical Injuries, Diseases and Operations. Carefully revised by the Author from the Seventh and enlarged English Edition. In two large and beautiful octavo volumes of nearly 2000 pages, illustrated by eight hundred and sixty-two engravings on wood. Cloth, $8 50 ; leather, $10 50; half Russia, raised hands, $11 50. Ofthe many treatises on Surgery which it has been our task to study, or our pleasure to read, there is none which in all points has satisfied us so well as the clas.su treatise of Epichsen. His polished, clear style, bis free- dom from prejudice and hobbies, his unsurpassed grasp ofhis subject, and vast clinical experience, qualify him admirably to write a model text-book. When we wish, at the least cost of time, to learn the most of a topic in surgery, we turn, by preference, to his work. It is a pleasure, therefore, to see that the appreciation of it is general, and has led to the appearance of anolher edi tion.—Med. and Surg. Reporter, Feb. 2,1878. Notwithstanding the increase in size, we observe that much old matter has been omitted. The entire work has been thoroughly written up, and not merely amend- ed by a few extra chapters A great improvement has been made in the illustrations. One hundred and fifty new ones have been added, and many of the old ones have been redrawn. The author highly appreciates the favor with which his work has been received by Ameri- can surgeons, and has endeavored to render his latest edition more than ever worthy of their approval. That he has succeeded admirably, must, we think, be the general opinion. We heartily recommend the book ti both student and practitioner.—N. Y.Med. Journal. Feb.1878. The seventh edition is before the world as the last word of surgical science. There may he monographs which excel It upon certain points, but as a con- spectus upon surgical principles and practice it is unrivalled. It will well reward practitioners to read it, for it has been a peculiar province of Mr. Erichseu to demonstrate the absolute interdepend- ence of medical and sargical science We need scarcely add, ia conclusion, that we heartily com- mend the work to students that they may be grounded in a sound faith, and to practitioners as an invaluable guide at the bedside.—Am Practi- tioner, April, 1878. For the past twenty years Erichsea’s Surgery has maintained itspLaee as the leading text-book, not only in this country, but in Great Bri tain. That it is able to hold its ground, is abundantly proven by the tho- roughness with which the present edition has been revised, and by the large amount of valuable mate- rial that has been added. Aside from this, one hun- dred anil fifty new illustrations have been inserted, including quite a number of microscopical appear- ances of pathological processes. So marked is this change for the better, that the work almost appears as an entirely new one.—Med. Record, Feb. 23,1878. IJOLMES (TIMOTHY), M.A., AA Surgeon to St. George’s Hospital, London. SURGERY, ITS PRINCIPLES AND PRACTICE. In one hand- some octavo volume of 968 pages, with 411 illustrations. Cloth, $6; leather, $7 ; half Russia, $7 50. It will be found a most excellent epitome of sur- gery by the general practitioner who has not the time togiveattentionto more minute and extended works, and to the medical student. In fact, we know of no one we can more cordially recommend. The author has succeeded well in giving a plain and, practical account of each surgical injury and die ease, and of the treatment which is most com- monly advisable. It will no doubt become a popu lar workin the profession, and especially as a text book.—Cincinnati Med. News, April, 1876. This is a work which has been lookedfor on both sides ofthe Atlantic with much interest. Mr. Holmes is a surgeon of large and varied experience, and one of the best known, and perhaps the most brilliant writer upon surgical subjects in England, It is a .rook for studentb—and au admirable one—and for the busy general practitioner. It will give a student til the knowledge needed to pass a rigid examina- tion. The book fairly justifies the high expectations ■hat were formed of it. Its style is clear and forcible, ,even brilliant at tiroes, and the conciseness needed to bring it witblD its nroper limits has not impaired its force and distinctness.— N. Y Med. Record, April 14, 1876. Henry C. Lea’s Son & Co.’s Publications—(Ophthalmology, etc.). 29 M/ELLS { J. SOELBERG), F.R.C.S. ’ * Professor of Ophthalmology in King’s College Hospital, London, Ac. A TREATISE ON DISEASES OF THE EYE. Third American, from the Third London Edition. Thoroughly revised, with copious additions, by Charles S. Bull, M D., Surgeon and Pathologist to the New York Eye and Ear Infirmary. In one large and very handsome octavo volume of 883 pages, with 254 illustrations on wood, six colored plates, and selections from the Test-types of Jaeger and Snellen. Cloth, $5 ; leather, $6 ; half Russia, raised bands, $6 50. The merits of Wells’ treatise on diseases of the eye have been so universally acknowledged, and are so familiar to all who profess to have given any at- tention to ophthalmic surgery, that any discussion of them at this late day will be a work of superero- gation. Very little that is practically useful in re- cent ophthalmic literature has eseaped the editor, and the third American edition is well up to the times. As a text-hook on ophthalmic surgery for the English-speaking practitioner, it is without a rival. —Am. Journ. of Med. S.i., Jan. 1881. The work has justly held a high place in English ophthalmic literature, and at the time of its first ap- pearance was the best treatise of its kind in the lan- guage. In the second edition, the author showed industi'ious research in adding new materia! from every quarter, and his spirit was eminently candid. A work thus built up by honest effort should not be suffered to die, and we are pleased to receive this third edition from the hands of Dr. Bull. His labor h is been arduous, as the very great number of addi- tions bracketed with his initial testify. Under the editorship which the third edition has enjoyed, the work is sure to sustain its good reputation, and to maintain its usefulness.—N. Y. idea. Journ., Jan. 1SS1. XTETTLESHIP {ED WARD), F.R.C.S., Ophthalmic Surg. and Lect. on Ophth. Surg. at St. Thomas' Hospital. London. THE STUDENT’S GUIDE TO DISEASES OF THE EYE. New Edition. With a Chapter on the Detection of Color-Blindness, by William Thomson, M D., Ophthalmologist to the Jefferson Medical College. In one royal 12mo. vol. of about 400 pages, with 138 illustrations. (In a few days .) This new edition of an excellent handbook embo- dies several improvements. A brief but c'ear intro- duction to the principles of geometrical optics so far as they concern the ophtbalmist, will be hailed by many a student whose preliminary scientific lessons are fadmg from his mind. The advantage to all readersof having this risumi of physical principles thus readily at hand is manifest. We confidently recommended the first edition; we have only now to congratulate the author ou his assuied success.— The Practitioner, Nov. 1882. flARTER (R. BRUDENELL), F.R.C.S., Ophthalmic Surgeon to St. George s Hospital, etc. A PRACTICAL TREATISE ON DISEASES OF THE EYE. Edit- ed, with test-types and Additions, by John Green, M.D. (of St. Louis, Mo.). In one handsome octavo volume of about 500 pages, and 124 illustrations. T>RO WNE {EDGAR A.), ■F* Surgeon to the Liverpool Eye and Ear Infirmary, andtothe Dispensary for Skin Diseases. HOWTO USE THE OPHTHALMOSCOPE. Being Elementary In- structions in Ophthalmoscopy, arranged for the Use of Students. In one small volume, royal 12mo., of 116 pages, with 35 illustrations. Cloth, $1. PSMARCH (Dr. FRIEDRICH), Af Professor of Surgery at the University of K el, etc. EARLY AID IN INJURIES AND ACCIDENTS. Five Ambulance Lectures. Translated by H. R. H. Princess Christian. In one handsome volume, small 12mo. of 109 pages, with 24 illustrations. Cloth, 75 cents. (Just Ready.) The first, or introductory lecture, gives a brief account of the structure and organization of the human body, illustrated by clear, suitable dia- grams. The second teaches how to give judicious help in ordinary injuries—contusions, wounds, haemorrhage and poisoned wounds. The third treats of first aid. iu cases of fracture aud of dislocations, in sprains and in burns. Next, the methods of affording first treatment in cases of frost-bile, of drowning:, of suffocation, of loss of consciousness and of poisoning are described; and the fifth lecture teaches how injured persons may be most safely aud easily transported to their homes, to a medical man or to a hospital. The illustrations in the book are clear and good, and it will, we doubt not, com- mand an extensive circulation. — Medical Times and Gazette, Nov. 4, 1882. SKEY’S OPERATIVE SURGERY. In 1 vol. 8vo. j’ of 661 pages, wirh 81 woodcuts. Cloth, $3 -25. COOPER’S LECTURES ON TIIE PRINCIPLES AND Practice of Surokry. In 1 vol. 8vo. 750 p. Cl h $2. 01ESON 'S INSTITUTES AND PRACTICED* SuR- siERY. Eighth Edit’n, improved and altered. With thirty-four plates. In two handsome octavo vol- umes, about 1000 pp. Leather $6 50. SARGENT ON BANDAGING ANDOTHER OPERA TIONS OF MINOR SURGERY. New Edition, witl an additionalchapter on Military Surgery. Out !3iao. vol. ol383pag9swithl8f wood-cuts. Cloth, #1 76. Lawson on injuries to the eye, orbii AND EYELIDS: Their Immediate and Remote Effects. With about one hundred illastrations In one very handsome octavo volume. Cloth, *3 50. THE PRINCIPLES AND PRACTICE OP SURGERY. By William Pikrik,F.R.S.E.,Profes’rof Surgery la the University of Aberdeen. Edited by John -N kill, M. D., Professor of Surgery in the Penn a. MedicalCollege,Surg’ntottae Pennsylvania Hos- pital, &e. In one very handsome octavo vol. of 780 pages, with 316 illustrations. Cloth, -$3 76. cBH 1 ON ON THE DISEASES, INJURIES, AND MALFORMATIONS OF THE RECTUM AND ANUS : with remarks on Habitual Constipation. Second American,from the Fourth and Enlarged London Edition. With illustrations. In one 8vo. vol. of 387 pages Cloth.#326. LAURENCE’S HA .il»i’ BOOK OF OPHTHALMIC SURGERY, fur the u-o of Praciitioners. Second Edition, rerised and enlarged With numerous illustrations. In one very handsome octavo vol- ivme. Cloth, $2 75. 30 Henry C. Lea’s Son & Co.’s Publications— (Otol., Med. Juris.). DURNETT (CHARLES H.), A.M , M.D., H Aura! Surg. to the Presb. Hasp., Surgeon-in-charge of the Infir. for His. of the Ear, Phila. THE EAR, ITS ANATOMY, PHYSIOLOGY AND DISEASES. A Practical Treatise for the Use of Medical Students and Practitioners. In one hand- some octavo volume of 619 pages, with eighty-seven illustrations: Cloth, $4 50; leather, $5 50; very handsome half Russia, raised bands, $6 00. On account of the great advances which have been made of late years in otology, and of the increased interest manifested in it, the medical profession will welcome this new work, which presents clearly and concisely its present aspect, whilst clearly indi- cating the direction in which further researches can be most profitably carried on. Dr. Barnett from his own matured experience, and availing himself of the observations and discoveries of others, has pro- duced a work which, as a text-hook, stauds facile princeps in our language. The book ought to be in the hands of every medical student, and its study will well repay the busy practitioner in the pleasure he will derive from the agreeable style in which many otherwise dry and mostly unknown subjects are treated. To the specialist the work is of the highest value, and his sense of gratitude to Dr. Burnett will, we hope, be proportionate to the amount of benefit lie can obtain from the careful study of the book, and a constant reference to its trustworthy pages.—Edinburgh Med. Jour., Aug. 1878. pOLITZER (ADAM), M.D., Imperial-Royal Professor of Aural Therapeutics in the University of Vienna. Chief of the Impe- rial-Royal University Clinic for Diseases of the Ear in the General Hospital, Imperial- Royal Public Aurist to the city of Vienna. A TEXT-BOOK OF THE EAR AND ITS DISEASES. Translated at the Author’s request, by James Patterson Cassells, M.D., F.F.P.S. In one hand- some octavo volume of 809 pages, with 257 illustrations. Cloth, $5 50. (Jvst Ready.) The name of Dr. Poiitzer is indissolubly associ- ated with the progress of aural surgery daring this generation. The tre.tise which he has written on this branch has long been a standard in Germany, and this translation of it, with the an,hor’s appro- bation, and by one of the most eminent aurists of Great Britain, will certainly take rank as a stand- ard work of reference for years to come. The vol- ume begins with a complete exposition of the anat- omy of the ear and the physiology of audition. Then follows a discussion of tire diseases of the several portions of the organ, the middle ear, the mastoid process, the internal ear, etc. Injuries of the organ and the relations of ear disease to life assurance are also treated of. The book closes with chapters on malformations of the ear, deaf-mutism, hearing instruments for the deaf and a satisfactory index. The text is elucidated by more than two hundred and fifty illustrations.—Medical and Sur- gical Reporter, Feb. 3, 1883. fVA YLOR (ALFRED S.), ~M. D., A Lecturer on Med. Jurisp. and. Chemistry in Ouy's Hospital. A MANUAL OF MEDICAL JURISPRUDENCE. Eighth Ameri- can from the Tenth London Edition, thoroughly revised and rewritten. Edited by John J. Reese, M.D., Professor of Medical Jurisprudence and Toxicology in the University of Pennsylvania. In one large octavo volume ol 937 pages, with 70 illustrations. Cloth, $5; leather, $6; half Russia, raised bands, $6 50. (Lately Issued.) The American editions of this standard manual have for a long time laid claim to the attention of the profession in this country; and that the profes- sion has recognized this claim with favor is proven by the call for frequent new editions of the work. This one, the eighth, comes before us as embodying the latest thoughts and emendations of Hr. Taylor, upon the subject to which he devoted bis life, with an assiduity and success which made him facile princeps among English writers on medical juris- prudence. Both the author and the book have made a mark too deep to be affected by criticism, whether it he censure or praise. In this case, how- ever, we shonld only have to seek for laudatory ferrns.—Am. -Tourn. of Med. Sci., Jan. 18S1. JJT THE SAME AUTHOR. THE PRINCIPLES AND PRACTICE OF MEDICAL JURIS- PRUDENCE. Third Edition. In two handsome octavo volumes. (In Press.) J>¥ THE SAME AUTHOR. POISONS IN RELATION TO MEDICAL JURISPRUDENCE AND MEDICINE. Third American, from the Third and Revised English Edition. In one large octavo volume of 788 pages. Cloth, $5 50 ; leather, $6 50. The present is based upon the two previous edi- tions ; but the complete revision rendered necessary by time has converted it into a new work.” This statement from the preface contains all that it is de- sired to know in reference to the new edition. The works of this author are already in the library of every physician who is liable to be called upon for medico-legal testimony (and what one is not?), so that all that is required to be known about the present book is that the author has kept it abreast with the times. What makes it now, as always, especially valuable to the practitioner is its conciseness and practical character, only those poisonous substances being described which give rise to legalinvestiga- tions. — The Clinic, Nov. 6, 1875. rpIDY {CHARLES MEYMOTT) M B., F.C.S, Professor of Chemistry and of Forensic Medicine and Public Health at the London Hospital, etc. LEGAL MEDICINE. Volume I. Embracing Evidence, The Signs op Death, Identity, The Causes op Death, The Post-Mortem, Sex, Monstrosities, Hermaphrodism, Expectation op Life, Presumption op Death and Survivorship, Heat and Cold, Burns, Lightning, Explosives, Starvation. Making a very hand- some imperial octavo volume of 664 pages, with 2 beautifully colored plates. Cloth, $6 ; leather, $7. (Just Ready.) He whose iucliuatious or necessities lead him to assume the functions of a medical jurist, wants a hook encyclopaedic in character, in which he may be reasonably sure of finding medico-iegal topics dis- cussed with judicial fairness, with sufficient com- pleteness, and with due attention to the most recent advances in medical science Mr. Tidy’s work bids fair to meet this need satisfactorily. The fact that the very numerous illustrative cases are drawn from many sources, and are not limited, as in Cas- per’s Haudbook, to the author’s own experience, and the additional fact that they are brought down to a very recent date, give them, for purposes of re- ference, a very obvious value.—Bouton Medical and Surgical Journal, Feb. 8, 1883. Henry C. Lea’s Son & Co.’s Publications—(Miscellaneous). 31 ROBERTS ( WILLIAM), M.D., A w hectv.rer on Medicine in the Manchester School of Medicine, etc. A PRACTICAL TREATISE ON URINARY AND RENAL DIS- EASES, including Urinary Deposits. Illustrated by numerous cases and engravings. Fourth American, from the Fourth Revised and Enlarged London Edition. In one large and handsome octavo volume. (Preparing.) ffHOMPSON (SIR HENRY), Surgeon and Professor of Clinical Surgery to University College Hospital. LECTURES ON DISEASES OF THE URINARY ORGANS. With illustrations on wood. Second American from the Third English Edition. In one octavo volume of 203 pages, with 25 illustrations. Cloth, $2 25. TOY THE SAME AUTHOR. ON THE PATHOLOGY AND TREATMENT OF STRICTURE OF THE URETHRA AND URINARY FISTULAS. With plates and wood-cuts. From the Third and revised English Edition. In one very handsome octavo volume. Cloth, $3 5u. BASHAM ON RENAL DISEASES : A Clinical Guide to Their Diaguosis and Treatment. In one 12mo. vol. of 304pages,with illustrations. Clntb, $2 00. A TREATISE ON FEVER. By Robert D. Lyons, K.C.C. In one octavo volume of 362 pages, Cloth,$2 25. LECTURES ON THE STUDY OF FEVER. By A. Hudson, M.D., M.R.I.A., Physician to the Meath Hospital. In one vol. 8vo. Cloth, $2 50. STOKES’LECTURES ON FEVER. Edited by John William Moore, M.D., F. K.Q.C.P. In one octavo volume of 26-1 pages. Cloth, $2 00. rpUKE (DANIEL HACK), M.D., Joint author of The Manual of Psychological Medicine, &c. ILLUSTRATIONS OF THE INFLUENCE OF THE MIND UPON THE BODY IN HEALTH AND DISEASE. Designed to illustrate the Action of the Imagination. New Edition In one handsome octavo volume (Preparing.) D> LAND FORD (0. FIELDING), M.D., F.R.C.P., Lecturer on Psychological Medicine at the School of St. George's Hospital, &c. INSANITY AND ITS TREATMENT: Lectures oil the Treatment, Medical and Legal, of Insane Patients. With a Summary of the Laws in force in the United States on the Confinement of the Insane. By Isaac Rav, M.D. In one very handsome octavo volume of 471 pages. TEA (HENRY C.). AND FORCE: ESSAYS ON THE WAGER OF LAW, THE WAGER OF BATTLE, THE ORDEAL AND TORTURE. Third Revised and Enlarged Edition. In one handsome royal 12mo. volume of 552 pages. Cloth, $2 50. (Lately Issued.) This valuable work is in reality a history of civi- , lization as interpreted by the progress of jurispru-| dence. ... in “Sapeistition and Force” we have j a pnilosophic survey of the long period intervening between primitive barbarity and civilized eniight- eument. There is not a chapter in the work that should not be most carefully studied, and however well versed the reader may be in the scieuce of jurisprudence, he will find much in Mr. Lea’s vol- ume of which he was previously ignorant. The book is a valuable addition to the literature of social science.— Westminster Review, Jan. 1880. The appearance of a new edition of Mr. Henry C. Lea’s "Superstition and Force” is a sign that our highest scholarship is not without honor in its na ti ve country. Mr. Lea has met every fresh demand for his work with a careful revision of it, and the present edition is not only fuller and, if possible, more accurate than either of the preceding, but, from the thorough elaboration, is more like a har- monious concert and less like a batch of studies.— The Nation, Aug. 1, 1878. Many will be tempted to say that this, like the •Decliueand Fall,”isone of the uncriticizable books. Its facts ate innumerable,its deductions simple and inevitable, and its cheva ux-de-frise of references bristling and dense enough to make the keenest, stoutest, and best equipped assailant think twice before advancing. Nor is there anything contro- versial in it to provoke assault. The author is no polemic. Though he obviously feels and thinks strongly, he succeeds in attaining impartiality. W betl er looked on as a picture or a mirror, a work such as this has a lasting value.—LippincotV* Magazine, Oct. 1878. £ Y THE SAME AUTHOR. STUDIES IN CHURCH HISTORY. THE RISE OF THE TEM- PORAL power—benefit of CLERGY—EXCOMMUNICATION. New Edition. In one very handsome royal octavo volume of about 500 pages. (In a few days.) A few notices of the previous edition are appended. Toe story was never told more calmly or with greater learning or wiser thought. We doubt, indeed, l i if any other study of this field can be compared with this for clearness, accuracy, and power. — Chicago' Examiner, Dec. 1870. Mr. Lea’s latest work,“ Studiesin Church History,” i fully sustains the promise of the first. It deals with three subjects—the Temporal Power, Benefit of. Clergy and Excommunication, the record of which; ias a peculiar importancefor the English student, and is a chapter on Ancient Law likely to be regarded as final. We can hardly pass from our mention of such works as these—with which that on “Sacerdotal ! Celibacy’’ should be included—without noting the | literary phenomenon that the head of one of the first i American houses is also the writer of some of its roost I original books.—London Athenasum, Jan. 7,1871. 32 Henry C. Lea’s Son & Co.’s Publications. INDEX TO CATALOGUE PAGE American Journal of the Medical Sciences . 3 American System of Gynaecology . . .23 Allen’s Anatomy 7 ♦Ashhurst’s Surgery ... . . 25 Ashton on the Rectum and Anus . ,29 Ashwellon Diseases of Women . . .23 Attfleid’s Chemistry 9 Barlow’s Practice of Medicine .... 14 Barnes’ Midwifery 24 ♦Birnes on Diseases of Women ... .22 Bartholow on Electricity 16 Basham on Renal Diseases ... 31 Bellamy’s Surgical Auatomy .... 6 Blandford on Insanity 31 Bloxam’s Chemistry .... .10 Bowman’s Practical Chemistry .... 9 ♦Bristowe’s Practice 14 Browne on Ophthalmoscope 29 Browne on the Throat ...... 19 ♦Bryant’s Practice of Surgery . . 28 ♦ Burnstead on Venereal 20 ♦Burnett on the Ear 30 ♦Carpenter’s Hainan Physiology ... 8 Carpenter on the Use and Abuse of Alcohol . 8 Carter ou the Eye 29 Century of American Medicine . . . .5 Chadwick on Diseases of Women . . .23 Chambers on Diet and Regimen . . . . 15 Churchill on Puerperal Fever . .23 Classen’s Chemistry 9 Cleland’s Dissector 6 Clowes’ Chemistry 10 Coats’ Pathology 13 Coleman's Dental Surgery 26 Condie on Diseases of Children . . . 23 Cooper’s Lectures on Surgery . . 29 ♦Cornil and Ranvier’s Pathological Histology . 13 Cornil on Syphilis 20 Atlas of Venereal Diseases . . 20 ♦Dalton’s Human Physiology 8 Davis’ Clinical Lectures 15 Druitt's Modern Surgery ... .27 Duncan on Diseases of Women . . . .23 ♦Duaglison s Medical Dictionary ... 4 Edis on Diseases of Women . ... 22 Ellis’ Demonstrations in Anatomy ... 7 ♦Emmet’s Gy usecology . . . 23 ♦Erichsen’s System of Surgery . 2S Esmarch’s Early Aid in Injuries and Accidents . 29 s'arqubarson’s Therapeutics . ... 11 Fenwick’s Diagnosis 14 Finlayson’s Clinical Diagnosis .... 16 Flint on Auscultation and Percussion . . 19 flint on the Heart . . . .19 Flint on Phthisis .... 19 Flint on Physical Exploration of the Lungs . 19 flint on Respiratory Organs . ]9 ♦Flint’s Clinical Medicine 15 Flint’s Essays 15 ♦Flint’s Practice of Medicine . . . .15 Foster’s Physiology 8 ♦Fothergill’s Handbook of Treatment . . 14 Fjwne3’ Elementary Chemistry . . . 10 Fox on Diseases of the Skin .... 19 Fuller on the Lungs, &c. 16 Galloway’s Analysis 9 Gibson s Surgery 29 Gluge’s Pathological Histology, by Leidy . . 14 ♦Gray’s Anatomy 6 Greene’s Medical Chemistry .... 9 Green’s Pathology and Morbid Anatomy . . 13 Griflitb’s Universal Formulary . . . .11 Gross on Foreign Bodies in Air-Passages . . 2b Gross on Impotence and Sterility . . .20 Gross on Urinary Organs 26 ♦Gross’System of Surgery .... 26 Gusserow on Uterine Tumors . . . .23 Gynecological Transactions 22 Habershon on the Abdomen . . . . .14 ♦Hamilton on Fractures and Dislocations . . 25 Hamilton on Nervous Diseases . . . . 18 Hartshorne’s Anatomy and Physiology . 6 Hartsnorne’s Conspectus of the MedicalSciences 6 Hartshorne’s Essentials ofMedicine . . 16 Heath’s Practical Anatomy 5 Hermann’s Experimental Pharmacology . . lo Hillier’s Handbook of Skin Diseases . 19 Hill on Venerea] Diseases 20 Hoblyn’s Medical Dictionary .... 4 PAUB Hodge’s Obstetrics 24 Hodge on Worneu . 22 Hoffmann and Power’s Chemical Analysis . . 10 Holden’s Landmarks . . . . b Holland’s Medical Notesand Reflection* . 14 ♦Holmes’ Surgery 28 ♦Holmes' System of Surgery . . . .27 Horner’s Anatomy and Histology . .6 Hudson on Fever . ... 31 Hyde on the Diseases of the Skin . . .19 Jones (C. Handheld) on Nervous Disorders . 18 Keating on Infants 21 King's Manual of Obstetrics . . .24 La Koclie on Pneumonia, Malaria, &c. . . 14 La Roche on Yellow Fevei 14 Laurence and Moon’s OphtbalmicSurgery . 29 Lawson on the Eye 29 Lea s Studiesin Church History . . 31 Lea’sSuperstition and Force . . . 81 Lee on Syphilis 20 Lehmann’s Chemical Physiology ... 9 ♦Leishinan’s Midwifery 24 Ludlow’s Manual of Examinations ... 6 Lyons on Fever ....... 31 Maisch’s Materia Medina .... .13 Medical News Meigs on Puerperal Fever 23 Miller’s Practice of Surgery . . . .27 Miller’s Principles of .-surgery . . . 27 Mitchell’s Nervous Diseases of Women . . 18 Montgomery on Pregnancy .... 23 Morris on Skin Diseases I9 Neill and Smith’s Compendium o f Med Science 6 Nettleship ou Diseases of the Eye . . .29 ♦Parrish’s Practical Pharmacy . Parry on Extra-CJterine Pregnancy . . .23 Parviu’s Midwifery 24 Pavy on Digestion 14 Pirrie’s System of Surgery 29 ♦Playfair’s Midwifery ...... 24 Playfair on Nerve Prostration and Hysteria . 24 Politzer on the Ear 30 Ramsbotham on Parturition . . . . 21 Remsen’s Principles of Chemistry ... 9 ♦Reynolds’ System of Medicine .... 17 Richardson’s Preventive Medicine . . .16 Roberts’ Principles and Practice of Surgery . 25 Roberts ou Urinary Diseases . . .31 Rodwell’s Dictionary of Science . ... 4 Sargent’s Minor Surgery 29 Schafer’s Histology 13 Seiler on the Throat 19 Sharpev and Quain’s Anatomy .... 5 Skey’s Operative Surgery 29 Slade on Diphtheria 11> Smith (Edward) on Consumption . . .16 Smith (Eust.) on Wasting Diseases i n Children 21 Smith (H. H.) and Horner’s Anatomical Atlas . 6 ♦Smith (J. L.) on Children ..... 21 ♦Stillb & Maisch’s Dispensatory . . . .12 ♦Still6’s Therapeutics 11 Stimson on Fractures 25 Stimson’s Operative Surgery ... .25 Stokes on Fever 31 Sturges’ Clinical Medicine 15 Tanner on Pregnancy ... . 23 Tanner’s Manual of Clinical Medicine . . 6 ♦Taylor’s Medical Jurisprudence . . 30 Taylor’s Prin. and Prac. of Med. Jurisprudence 30 Taylor on Poisons . . . .30 ♦Thomas on Diseases of WorJ8n . 22 Thompson on Stricture 31 Thompson on Urinary Organs . • 31 Tidy’s Legal Medicine 30 Todd on Acute Diseases . ..15 Tuke on the Influence of the Mind . . .31 Walshe on the Heart 16 Watson’s Practice of Physic . . . .16 ♦Wells on the Eye 29 West on Diseases of Children . . . .21 West on Diseases of Women . . 21 Weston Nervous Disorders ofChildren . . 21 Williams on Consumption ..... 16 Wilson’s Handbook of Cutaneous Medicine . 19 Wilson’s Human Anatomy . ... 7 Winckel on Childbed . . . . .21 Wohler’s Organic Chemistry .... 9 Woodbury’s Practice 16 Books marked * are also bound in half Russia. HENRY C. LEA’S SON & CO.—Philadelphia.