THE MEDICAL STUDENT'S MANUAL OF s CHEMISTRY BY l£' K. WITTHAUS, A.M., M.D. t|J * PROFESSOR OF CHEMISTRY AND TOXICOLOGY IN THE UNIVERSITY OF BUFFALO; PROFESSOR OF CHEM- ISTRY AND TOXICOLOGY IN THE UNIVERSITY OF VERMONT ; PROFESSOR OF PHYSIOLOGICAL CHEMISTRY IN THE UNIVERSITY OF THE CITY OF NEW YORK; CHEMIST TO THE CITY OF BUFFALO *, MEMBER OF THE CHEMICAL SOCIETIES OF PARIS AND BERLIN ; MEMBER OF THE AMERICAN CHEMICAL society; fellow of the American acad- emy OF MEDICINE, ETC. NEW YORK WILLIAM WOOD & COMPANY 56 & 58 Lafayette Place 1883 Copyright, 1883, by WILLIAM WOOD & COMPANY. Trow’s Printing and Bookbinding Company 201-213 East Tivelth St. NEW YORK PREFACE. In venturing to add another to the already long list of chemical text-books, the author trusts that he may find some apology in this, that the work is intended solely for the use of a class of students whose needs in the study of this science are peculiar. While the main foundations of chemical science, the philosophy of chemistry, must be taught to and studied by all classes of students alike, the subsequent development of the study in its details must be moulded to suit the purposes to which the student will subsequently put his knowledge. And particularly in the case of medical students, in our present defective methods of medical teaching, should the sub- ject be confined as closely as may be to the general truths of chemistry and its applications to medical science. In the preparation of this Manual the author has striven to pro- duce a work which should contain as much as possible of those por- tions of special chemistry which are of direct interest to the medical practitioner, and at the same time to exclude so far as possible, without detriment to a proper understanding of the subject, those portions which are of purely technological interest. The descriptions of pro- cesses of manufacture are therefor made very brief, while chemical physiology and the chemistry of hygiene, therapeutics, and toxicology have been dwelt upon. The work has been divided into three parts. In the first part the principles of chemical science are treated of, as well as so much of chemical physics as is absolutely requisite to a proper understanding of that which follows. A more extended study of physics is purposely avoided, that subject being, in the opinion of the author, rather within the domain of physiology than of chemistry. The second part treats of special chemistry, and in this certain departures from the methods usually followed in chemical text-books are to be noted. The elements are classed, not in metals and metal- IV PREFACE. loids, a classification as arbitrary as unscientific, but into classes and groups according to their chemical characters. In the text the formula, of a substance is used in most instances in place of its name, after it has been described, with a view to giving the student that familiarity with the notation which can only be obtained by continued use. As the distinction between inorganic and organic chemistry is merely one of convenience, the consideration of the carbon compounds is made to follow in its logical place after that of the element carbon. In the third part those operations and manipulations which will be of utility to the student and physician are briefly described; not with the expectation that these directions can take the place of actual ex- perience in the laboratory, but merely as an outline sketch in aid thereto. Although the Manual puts forth no claim as a work upon analyti- cal chemistry, we have endeavored to bring that branch of the subject rather into the foreground so far as it is applicable to medical chem- istry. The qualitative characters of each element are given under the appropriate heading, and in the third part, systematic schemes for the examination of calculi and of simple chemical compounds are given. Quantitative methods of interest to the physician are also described in their appropriate places'. In this connection the author would not be understood as saying that the methods recommended are in all in- stances the best known, but simply that they are the best adapted to the limited facilities of the physician. The author would have preferred to omit all mention of Troy and Apothecaries’ weight, but in deference to the opinions of those vener- able practitioners who have survived their student days by a half cen- tury, those weights have been introduced in brackets after the metric, as the value of degrees Fahrenheit have been made to follow those Centigrade. K. A. W. Buffalo, N, Y., September 16, 1S83. TABLE OF CONTENTS. PAGE PART I—INTRODUCTION l General Properties op Matter 2 Indestructibility 2 Weight 2 Specific gravity 2 States of matter 6 Divisibility 7 Elements 8 Combination op Elements 8 Atomic Theory 9 Atomic and Molecular Weights 11 Valence or Atomicity 15 Symbols—Formulae—Equations 16 Electrolysis 17 Acids, Bases, and Salts 19 Oxides and Hydrates 21 Nomenclature 22 Radicals < 25 Constitution 25 Classification op Elements 28 Physical Characters 29 Crystallization 29 Isomorphism 82 Dimorphism 33 Allotropy 33 Solution 33 Diffusion 34 Specific heat 35 Spectroscopy 35 Polarimetry 38 VI CONTENTS. PAGE PART II.—SPECIAL CHEMISTRY 39 Typical Elements 39 Hydrogen 89 Oxygen 42 Ozone 44 Water 44 Hydrogen dioxide 54 Acidulous Elements 55 Chlorine Group 55 Fluorine 55 Hydrogen fluoride 55 Chlorine 56 Hydrogen chloride 58 Compounds of chlorine and oxygen 59 Bromine 60 Hydrogen bromide 60 Oxacids of bromine 61 Iodine 61 Hydrogen iodide 62 Oxacids of iodine 63 Sulphur Group 63 Sulphur 64 Hydrogen sulphide 65 Sulphur dioxide 67 Sulphur trioxide 68 Hydrosulphurous acid 68 Sulphuric acid 68 Pyrosulphuric acid 70 Selenium 70 Tellurium 71 Nitrogen Group 71 Nitrogen .. 71 Atmospheric air 72 Ammonia 73 Nitrogen monoxide 74 Nitrogen dioxide 75 Nitrogen trioxide 75 Nitrogen tetroxide 75 Nitrogen pentoxide 76 Nitrogen acids 76 Nitric acid 77 Compounds of nitrogen with the halogens 78 Phosphorus 79 Hydrogen phosphides 83 Oxides of phosphorus. 83 Phosphorus acids 84 Compounds of phosphorus with the halogens 86 Arsenic 86 Hydrogen arsenides 87 Oxides of arsenic 88 CONTENTS. PAGE Arsenic acids 90 Sulphides of arsenic 90 Haloid compounds of arsenic 91 Arsenical poisoning 91 Analytical 94 Antimony 99 Hydrogen antimonide 99 Oxides of antimony 99 Antimony acids 100 Chlorides of antimony 100 Sulphides of antimony 101 Antimonial poisoning 102 Analytical 102 Boron Group 102 Boron 102 Boron oxide and acids 103 Carbon Group 103 Carbon 103 Compounds op Carbon 106 Hydrocarbons CnHin + 110 Haloid derivatives 112 Alcohols CnH2» + aO 115 Simple ethers 126 Acids C»H2nOa 129 Compound ethers 135 Aldehydes C»H3„0 138 Ketones CnH2nO 141 Monamines 143 Monamides 145 Amido acids 146 Sulphides, etc 156 Allylic series 157 Acids C„H2;l_202 160 Aldehydes CnH2a_20 160 Hydrocarbons C»H2n 164 Alcohols C»H2„ + 302 165 Acids C«H2Jl03 168 Acids C„H2»_204 182 Amines 185 Amides 186 Alcohols C»H2ll + 203 200 Glycerides 201 Neutral fats and oils 203 Hydrocarbons C„H2„_2 209 Alcohols C„H2n + 204 210 Acids CnH2„_20(! 210 Hydrocarbons C»H2»_ . 212 Carbohydrates 216 Hydrocarbons C„ H2„ _ 230 Phenols 233 Aromatic alcohols 236 CONTENTS. PAGE Diatomic aromatic hydrates 236 Triatomic aromatic hydrates 237 Acids 237 Aldehydes 239 Amines 240 Hydrocarbons CMH2„_ 8 242 Alcohols H2„ _ 80 242 Hydrocarbons C„H2n-io 243 Hydrocarbons C»H an — 243 Hydrocarbons C»H2n_i4 244 Hydrocarbons CnH2n_16 244 Hydrocarbons C«H2n_18 244 Cyanogen compounds 245 Compounds of unknown constitution 248 Glucosides 248 Alkaloids 251 Albuminoids and gelatinoids 260 Animal cryptolytes 268 Animal coloring matters 269 Silicon 272 Vanadium Group 273 Vanadium 273 Niobium 273 Tantalium 273 Molybdenum Group 273 Molybdenum 273 Tungsten 273 Osmium 273 Amphoteric Elements 274 Gold Group 274 Gold 274 Iron Group 274 Chromium 275 Analytical characters 276 Manganese 276 Compounds 276 Salts 277 Analytical characters 277 Iron 277 Compounds 278 Salts 280 Analytical characters 282 Aluminium Group 283 Glucinium 283 Aluminium 283 Compounds 284 Salts 284 Analytical characters 285 Scandium 286 Gallium 286 CONTENTS IX PAGE Indium 28(5 Uranium Group 287 Uranium 287 Lead Group 287 Lead 287 Compounds 288 Salts 289 Analytical characters 290 Toxicology 290 Bismuth Group 291 Bismuth 291 Compounds 292 Salts of bismuth 292 Salts of bismuthyl . 292 Analytical characters 293 Toxicology 293 Tin Group 293 Titanium 293 Zirconium 293 Tin 294 Compounds 294 Analytical characters 295 Platinum Group 295 Rhodium Group 295 Platinum 295 Palladium 296 Rhodium 296 Ruthenium / 296 Iridium 296 Basylous Elements 297 Sodium Group 297 Lithium 297 Analytical characters 297 Sodium 298 Compounds 298 Salts 300 Analytical characters ... 303 Potassium 303 Compounds 304 Salts 305 Analytical characters 310 Toxicology 310 Rubidium 310 Caesium 310 Silver 310 Analytical characters 311 Toxicology 311 Ammonium 311 Compounds 312 Salts 313 X CONTENTS PAGE Analytical characters 313 Toxicology 314 Thallium Group 314 Thallium 314 Calcium Group 314 Calcium 314 Compounds 315 Salts 316 Analytical characters 318 Strontium 319 Barium 319 Compounds 319 Salts 319 Analytical characters 320 Toxicology 320 Magnesium Group 320 Magnesium 320 Compounds 321 Salts 321 Analytical characters 322 Zinc 323 Compounds 323 Salts 323 Analytical characters 323 Toxicology 323 Cadmium. 325 Nickel Group 325 Nickel. 325 Cobalt 325 Copper Group 326 Copper 326 Compounds 326 Salts 327 Analytical characters 328 Toxicology 329 Mercury 330 Compounds 330 Salts 333 Analytical characters 334 Toxicology 335 Cerium Group 336 Yttrium 336 Cerium 336 Lanthanium i 336 Didymium 336 Erbium 336 Ytterbium 336 Thorium Group 336 Thorium 336 CONTENTS. XI PART m— CHEMICAL TECHNICS *33? General Rules 337 Reagents 338 Glass tubing 338 Collection of gases , 339 Solution 340 Precipitation, decantation, etc 341 Evaporation, drying, etc 342 Weighing 345 Measuring 346 Scheme for Analysis of Calculi 348 Scheme for Analysis of Mineral Compounds 349 Table of Solubilities 354 Table of Weights and Measures 355 INDEX 357 THE MEDICAL STUDENT’S MANUAL OF CHEMISTRY. PART I. INTRODUCTION. The simplest definition of chemistry is a modification of that given by Webster: That branch of science which treats of the composition of sub- stances, their changes in composition, and the laws governing such changes. If a bar of soft iron be heated sufficiently it becomes luminous; if caused to vibrate it emits sound ; if introduced within a coil of wire through which a galvanic current is passing, it becomes magnetic and at- tracts other iron brought near it. Under all these circumstances the iron is still iron, and so soon as the heat, vibration, or galvanic current ceases, it will be found with its original characters unchanged ; it has suffered no change in composition. If now the iron be heated in an atmosphere of oxygen gas it burns and is converted into a substance which, although it contains iron, has neither the appearance nor the properties of that metal. The iron and a part of the oxygen have disappeared and have been con- verted into a new substance, differing from either ; there has been change in composition, there has been chemical action. Changes wrought in matter by physical forces, such as light, heat and electricity are temporary, and last only so long as the force is in activity; except in the case of changes in the state of aggregation, as when a substance is pulverized or fashioned into given shape. Changes in chemical composition are permanent, last- ing until some other change is brought about by another manifestation of chemical action. However distinct chemical may thus be from physical forces, it is none the less united with them in that grand correlation whose existence was first announced by Grove, in 1842. As, from chemical action, manifesta- tions of every variety of physical force may be obtained : light, heat, and mechanical force from the oxidation of carbon ; and electrical force from the action of zinc upon sulphuric acid—so does chemical action have its origin, in many instances, in the physical forces. Luminous rays bring about the chemical decomposition of the salts of silver, and the chemical union of chlorine and hydrogen ; by electrical action a decomposition of many compounds into their constituents is instituted, while instances are 2 MANUAL OF CHEMISTRY. abundant of reactions, combinations, and decompositions which require a certain elevation of temperature for their production. While, therefor, chemistry in the strictest sense of the term, deals only with those actions which are attended by a change of composition in the material acted upon, yet chemical actions are so frequently, nay universally, affected by existing physical conditions, that the chemist is obliged to give his attention to the science of physics, in so far, at least, as it lias a bearing upon chemical reactions, to chemical physics—a branch of the subject which has afforded very important evidence in support of theoretical views originating from purely chemical reactions. General Properties of Matter. Indestructibility.—The result of chemical action is change in the composition of the substance acted upon, a change accompanied by cor- responding alterations in its properties. Although we may cause matter to assume a variety of different forms and render it, for the time being, invisible, yet in none of these changes is there the smallest particle of matter destroyed. When carbon is burned in an atmosphere of oxygen, it disappears, and, so far as we can learn by the senses of sight or touch, is lost; but the result of the burning is an invisible gas, whose weight is equal to that of the carbon which has disappeared, plus the weight of the oxygen required to burn it. Weight. —All bodies attract each other with a force which is in direct proportion to the amount of matter which they contain. The force of this attraction exerted upon surrounding bodies by the earth becomes sensible as weight, when the motion of the attracted body toward the centre of gravity of the earth is prevented. In chemical operations we have to deal with three hinds of weight: absolute, apparent, and specific. The Absolute Weight of a body is its weight in vacuo. It is deter- mined by placing the entire weighing apparatus under the receiver of an air-pump. The Apparent Weight, or Relative Weight, of a body is that which we usually determine with our balances, and is, if the volume of the body weighed be greater than that of the counterpoising weights, less than its true weight. Every substance in a liquid or gaseous medium suffers a loss of apparent weight equal to that of the volume of the medium so dis- placed. For this reason the apparent weight of some substances may be a minus quantity ; thus, if the air contained in a vessel suspended from one arm of a poised balance be replaced by hydrogen, that arm of the balance to which the vessel is attached will rise, indicating a diminution in weight. (See Weighing ; Part III.) The Specific Weight or Specific Gravity of a substance is the weight of a given volume of that substance, as compared with the weight of an equal bulk of some substance, accepted as a standard of comparison, under like conditions of temperature and pressure. The sp. gr. of solids and liquids are referred to water ; those of gases to air or to hydrogen. Thus the sp. gr. of sulphuric acid being 1.8, it is, volume for volume, one and eight-tenths times as heavy as water. As, by reason of their different rates of expansion by heat, solids and liquids do not have the same sp. gr. at all temperatures, that at which the observation is made should always be noted, or some standard temperature adopted. The standard tempera- GENERAL PROPERTIES OF MATTER. 3 ture adopted by some continental writers and in the U. S. P. is 50° (59° F.); other standard temperatures are 4° (39.2° F.), the point of greatest density of water, used by most continental writers, and 15.6° (60° F.), used in Great Britain and to some extent in this country. The determination of the specific weight of a substance is frequently of great service. Sometimes it affords a rapid means of distinguishing between two substances similar in appearance ; sometimes in determining the quantity of an ingredient in a mixture of two liquids, as alcohol and water ; and frequently in determining approximately the quantity of solid matter in solution in a liquid. It is the last object which we have in view in determining the sp. gr. of the urine. An aqueous solution of a solid has a higher sp. gr. than pure water, the increase in sp. gr. following a regular but different rate of increase with each solid. In a simple solution—one of common salt in water, for instance—the proportion of solid in solution can be de- termined from the sp. gr. In complex solutions, such as the urine, the sp. gr. does not indicate the propor- tion of solid in solution with accuracy. In the absence of sugar and albumen, a determination of the sp. gr. of urine affords an indication of the amount of solids sufficiently accurate for usual clinical purposes. More- over, as urea is much in excess over other urinary sol- ids, the oscillations in the sp. gr. of the urine, if the quantity passed in twenty-four hours be considered, and in the absence of albumen and sugar, indicate the variations in the elimination of urea, and consequently the activity of disassimilation of nitrogenous material. To determine the sp. gr. of substances, different methods are adopted, according as the substance is in the solid, liquid, or gaseous state ; is in mass or in powder; or is soluble or insoluble in water. Solids.—The substance is heavier than water, insoluble in that liquid, and not in powder.—It is attached by a fine silk fibre or platinum wire to a hook arranged on one arm of the balance, and weighed. A beaker full of pure water is then so placed that the body is immersed in it (Fig. 1.), and a second weighing made. By dividing the weight in air by the loss in water, the sp. gr. (water =1.00) is obtained. Example: -Fig. 1. A piece of lead weighs in air 82.0 A piece of lead weighs in water 74.0 Loss in water 7.1 82.0 = 11.55 = sp. gr. of lead. 7.1 The substance is in powder, insoluble in water.—The specific gravity bottle (Fig. 2) filled with water, and the powder previously weighed and in a separate vessel, are weighed together. The water is poured out of the bottle, into which the powder is introduced with enough water to fill the bottle completely : the weight of the bottle and its contents is now determined. The weight of the powder alone, divided by the loss between the first and second weighings, is the specific gravity. Example : Weight of iron filings used 6 562 Weight of iron filings and sp. gr. bottle filled with water 148.327 Weight of sp. gr. bottle containing iron filings and filled with water 147.470 Water displaced by iron 0.857 6.562 — 7.65 = sp. gr. of iron. 0.857 4 MANUAL OF CHEMISTRY. The substance is lighter than water.—A sufficient bulk of some heavy substance, whose sp. gr. is known, is attached to it and the same method followed, the loss of weight of the heavy substance being subtracted from the total loss. Example : A fragment of wood weighs 24 A fragment of lead weighs 44 Wood with lead attached weighs 68 Wood with lead attached weighs in water 16 Loss of weight of combination 52 Loss of weight of lead in water. 6 Loss of weight of wood 46 24 — = 0.5217 = sp. gr. of wood. 46 The substance is soluble in or decomposable by water.—Its specific gravity, referred to some liquid not capable of acting on it, is determined, using that liquid as water is used in the case of insoluble substances. The sp. gr. so obtained, multiplied by that of the liquid used, is the sp. gr. sought. Example : A piece of potassium weighs 2.576 , A sp. gr. bottle full of naphtha, sp. gr. 0.758, weighs. 22.784 25.360 The bottle with potassium and naphtha weighs 23.103 Loss S 2.257 2.576 = 1.141 x 0.758 = 0.865 = sp. gr. of potassium. 2.257 Liquids.—The sp. gr. of liquids is determined by the specific gravity bottle, sometimes called picnometer, or by the spindle or hydrometer. By the bottle.—This method is the more accurate, and, if a balance be at hand, is easily conducted. A bottle of thin glass (Fig. 2) is so made as to contain a given volume of water, say 100 c.c., at 15° C., and its weight is determined once for all. To use the picnometer, it is filled with the liquid to be examined and weighed. The weight obtained, minus that of the bottle, is the sp. gr. sought if the bottle contain 1000 c.c. ; -fe if 100 c.c., etc. Example : Having a bottle whose weight is 35.35, and which contains 100 c.c. ; filled with urine it weighs 137.91, the sp. gr. of the urine is 137.91-35.35=102.56 x 10=1025.6 -Water=1000. By the spindle.—The method by the hydrometer is based upon the fact that a solid will sink in a liquid whose sp. gr. is greater than its own, until it has displaced a volume of the liquid whose weight is equal to its own ; and all forms of hydrometers are simply contrivances to measure the volume of liquid which they displace when immersed. The hydrome- ter most used by physicians is the urinometer (Fig. 3); it should not be chosen too small, as the larger the bulb, and the thinner and longer the stem, the more accurate are its indications. The most convenient method of using the instrument is as follows : The cylinder, which should have a foot and rim, but no pouring lip, is filled to within an inch of the top ; the spindle is then floated and the cylinder completely filled with the liquid under examination (Fig. 3). The reading is then taken at the highest point a, where the surface of the liquid comes in contact with the spindle.* * The advantages of the method described over that usually followed are : Greater facility in reading, less liability to error, the possibility of taking the reading in opaque liquids, and the fact that readings are made upward, not downward. The spindles require to be specially graduated, and are made by Baudin, of Paris, and Eimer & Amend, of New York. GENERAL PROPERTIES OF MATTER. 5 In all determinations of sp. gr. the liquid examined should have the temperature for which the instrument is graduated, as all liquids expand with heat and contract when cooled, and consequently the result obtained will be too low if the urine or other liquid be at a temperature above that at which the instrument is intended to be used, and too high if below that temperature. An accurate correction may be made for temperature in Fig. 2. Fig. 3. simple solutions ; in a complex fluid like the urine, however, this can only be done roughly by allowing 1° of sp. gr. for each 3° C. (5.4° Fahr.) of variation in temperature. Gases and Vapors.—The specific gravities of gases and vapors are of great importance in theoretical chemistry, as from them we can determine molecular weights, in obedience to the law of Avogadro (p. 14). Gases.—The specific gravities of gases are obtained as follows: A glass flask of about 300 c.c. capacity, having a neck 20 centimetres long and 6 millimetres in diameter, and fitted with a glass stopcock, is filled with mercury; reversed over mercury; and filled with the gas to just below the stopcock. The stopcock is now closed ; the temperature, t; the barometric pressure, H ; and the height of the mercurial column in the neck above that in the trough, A, are determined, and the flask weighed. Let P be the weight found, and V the capacity of the flask, determined once for all, then _ y _ the volume of the gas at 0° and 760 mm, 760 (1+0.00366 t) 0 The flask is then brought under the receiver of an air-pump, the glass stopcock being open, and the air alternately exhausted and allowed to enter until the gas in the flask is replaced by air. The temperature t', the barometric pressure H7, and the weight of the flask filled with air 1>/. are now determined. From these results the weight, K, of the gas occupying the volume V0 is obtained by the formula : V H' K=P—P'+ — x 0.001293 760 (1+0.00366 «') The sp. gr. referred to air is found by the formula : _ K V„x 0.001293 and that referred to hydrogen by the formula : K V0 x 0.001293 x 0.06927 6 MANUAL OF CHEMISTKY. Vapors.—The specific gravity of vapors is best determined by Meyer’s method, as follows: A small, light glass vessel (Fig. 4) is filled completely with the solid or liquid whose vapor density is to be determined, and weighed ; from this weight that of the vessel is subtracted ; the difference being the weight of the substance P. The small vessel and contents are now introduced into the large branch of the apparatus (Fig. 5), whose weight is then determined. The apparatus is now filled with mer- cury, the capillary opening at the top of the larger branch is closed by the blow-pipe, and the whole again weighed. The apparatus is suspended by a metallic wire near the bottom of a long tube closed at the bottom, and containing about 51) c.c. of some liquid whose boiling-point is con- stant and higher than that of the substance experimented on. When the liquid has been heated to active boiling, and the mercury ceases to escape from the small tube, the barometric pressure and the temperature of the air are observed. After the apparatus is cooled, the tube (Fig. 5), with its contents, is weighed, and the difference in the level of mercury which existed in the two branches during the heating determined by breaking the capillary point, tilting the apparatus un- til the smaller branch is completely filled, marking the level of mercury in the larger branch, and afterward measuring the distance from that point to the opening. By the above process the following factors are determined: P = weight of substance ; T = boiling-point of external liquid ; t = temperature of air; H = barometric pressure reduced to 0° ; A = difference in level of mercury in two branches of tube; h' — tension of vapor of mercury at T; a — weight of mercury used; q = weight of mercury required to fill the tube Pig. 4; r = weight of mercury remaining in the apparatus after heating. From these the specific gravity, air = 1, is obtained by the equation: P 160 (1 + 0.00367 T) 13.59 U~(H+A+A') 0.0012933 [(«+° 0.1915 2.11 Crystallized at 4- 1C). 7° 0 2737 3.01 Crystallized at + 233. 2° 0.3603 3.99 Amorphous. 0.255 2.81 Carbon. Diamond at — 50.5° .... 0.0635 0.76 Diamond at -f- 140° 0 2218 2.66 Diamond at -j- 985° 0.4589 5.51 Graphite at — 50.3° 0.1138 1.37 Graphite at -f- 138.5° 0.2642 3.05 Graphite at 4- 977.9° 0.4670 5.60 Wood charcoal.... 0.2415 2.90 Specific Atomic heat. heat. Silicon. Crystallized at — 39.8°... ... 0.1360 3.81 Crystallized at -j-* 128.7°... ... 0.1964 5.50 Crystallized at -j- 232.4°... ... 0.2029 5.68 Fused at -j- 100° ... ... 0.175 4.90 Sulphur. Orthorhombic at 45° ... ... 0.163 5.22 Orthorhombic at -j- 99° .. . ... 0.1776 5.68 Liquid at -j- 150“ ... ... 0.234 7.49 Recently fused at -j- 98° ... ... 0.20259 6.48 Phosphorus. Yellow at — 78° ... ... 0.174 5.39 Yellow at + 30° ... ... 0.202 6.26 Liquid at 100° ... ... 0.212 6.57 Amorphous at -j- 98° ... ... 0.170 5.27 It will be observed that, as the temperature of the solid element is in- creased, the atomic heat more nearly approaches 6.4. It will further be noticed that those elements with which the perturbations occur are those which are capable of existing in two or more allotropic forms (see p. 63). As in the passage of an element from one allotropic condition to another, absorption or liberation of heat always takes place, as the result of “ inte- rior work ; ” it is probable that these perturbations are due to a constant tendency of the element to pass from one allotropic condition to another. The atomic heats of those elementary gases which have only been liquefied by enormous cold and pressure are tolerably constant at about 2.4. Molecular Weight.—The molecular weight of a substance is the weight of its molecule as compared with the weight of an atom of hydrogen. It is also, obviously, the sum of the weights of all the atoms making up the molecule. A very ready means of determining the molecular weight of any sub- stance which we can convert into a gas is based upon Avogadro’s law. The sp. gr. of a gas is the weight of a given volume as compared with that of an equal volume of hydrogen. But these equal volumes contain equal numbers of molecules (p. 11), and therefor, in determining the sp. gr. of a gas, we obtain the weight of its molecule as compared with that of a molecule of hydrogen; and, as the molecule contains two atoms of hy- drogen, while one atom of hydrogen is the unit of comparison, it follows that the specific gravity of a gas, multiplied by two, is its molecular weight. For example, the gas acetylene and the liquid benzene each contain 92.31 per cent, of carbon, and 7.69 per cent, of hydrogen; which is equiv- alent to 24 parts, or two atoms of carbon; and 2 parts, or two atoms of VALENCE OR ATOMICITY. 15 hydrogen. The sp. gr. of acetylene, referred to hydrogen = 2, is 13 ; its molecular weight is, therefor, 26, and its molecule contains two atoms of carbon and two atoms of hydrogen. The sp. gr. of vapor of benzene is 39 ; its molecular weight is, therefor, 78, and its molecule contains six atoms of carbon and six atoms of hydrogen. The vapor densities of comparatively few elements are known : Hydrogen Vapor Density. 1 Atomic Weight. 1 Molecular Weight. 2 Oxygen 16 16 32 Sulphur 32 32 64 Selenium 82 79 164 Tellurium 130 128 260 Chlorine 35.5 35 5 71 Bromine 80 80 160 Vapor Atomic Molecular Density. Weight. Weight. Iodine 127 127 254 Phosphorus .... (53 31 12(5 Arsenic 150 75 300 Nitrogen 14 14 28 Potassium 39 39 78 Cadmium 5(5 112 112 Mercury 1U0 200 200 The atomic weight being, in most of the above instances, equal to the vapor density, and to half the molecular weight, it may be inferred that the molecules of these elements consist of two atoms. Noticeable discrep- ancies exist in the case of four elements. The molecular weights of phosphorus and arsenic, as obtained from their vapor densities, are not double but four times as great as their atomic weights. The molecules of phosphorus and arsenic are, therefor, supposed to contain four atoms. Those of cadmium and mercury contain but one atom. Valence or Atomicity. It is known that the atoms of different elements possess different powers of combining with and of replacing atoms of hydrogen. Thus : One atom of chlorine combines with one atom of hydrogen, One atom of oxygen combines with two atoms of hydrogen, One atom of nitrogen combines with three atoms of hydrogen, One atom of carbon combines with four atoms of hydrogen. The valence, atomicity, or equivalence of an element is the saturating power of one of its atoms as compared with that of one atom of hydrogen. Elements may be classified according to their valence into— Univalent elements or monads Cl' Bivalent elements or dyads O" Trivalent elements or triads B'" Quadrivalent elements or tetrads CiT Quinquivalent elements or pentads Pv Sexvalent elements or hexads Wyi Elements of even valence, i.e., those which are bivalent, quadrivalent, or sexvalent are sometimes called artiads ; those of uneven valence being designated as per'issads. In notation the valence is indicated, as above, by signs placed to the right and above the symbol of the element. But the valence of the elements is not fixed and invariable. Thus, while chlorine and iodine each combine with hydrogen, atom for atom, and in those compounds are consequently univalent, they unite with each other to form two compounds—one containing one atom of iodine and one of chlorine, the other containing one atom of iodine and three of chlorine. Chlorine being univalent, iodine is obviously trivalent in the second of 16 MANUAL OF CHEMISTRY. these compounds. Again, phosphorus forms two chlorides, one contain- ing three, the other five atoms of chlorine to one of phosphorus. In view of these facts, we must consider, either : 1, that the valence of an element is that which it exhibits in its most saturated compounds, as phosphoi’us in the pentachloride, and that the lower compounds are non- saturated and have free valences ; or 2, that the valence is variable. The first supposition depends too much upon the chances of discovery of com- pounds in which the element has a higher valence than that which might be considered as the maximum to-day. The second supposition—notwith- standing the fact that, if we admit the possibility of tw'o distinct valences, we must also admit the possibility of others—is certainly the more tenable and the more natural. In speaking, therefor, of the valence of an element, we must not consider it as an absolute quality of its atoms, but simply as their combining power in the particular class of compounds under consideration. Indeed, compounds are known in whose molecules the atoms of one ele- ment exhibit two distinct valences ; thus, ammonium cyanate contains two atoms of nitrogen : one in the ammonium group is quinquivalent, one in the acid radical is trivalent. When an element exhibits different valences, these differ from each other by two. Thus, phosphorus is trivalent or quinquivalent ; platinum is bivalent or quadrivalent. Symbols—Formulae—Equations. Symbols.—These are conventional abbreviations of the names of the elements, whose purpose it is to introduce simplicity and exactness into descriptions of chemical actions. They consist of the initial letter of the Latin name of the element, to which is usually added one of the other letters. If there be more than two elements whose names begin with the same letter, the single-letter symbol is reserved for the commonest ele- ment. Thus, we have nine elements whose names begin with C ; of these the commonest is Carbon, whose symbol is C ; the others have double- letter symbols, as Chlorine, Cl; Cobalt, Co ; Copper, Cu (Cuprum), etc. These symbols do not indicate simply an indeterminate quantity, but one atom of the corresponding element. When more than one atom is spoken of, the number of atoms which it is desired to indicate is written either before the symbol, or, in small figures, after and below it; thus, H indicates one atom of hydrogen; 2C1, two atoms of chlorine; C4, four atoms of carbon, etc. Formulae.—What the symbol is to the element, the formula is to the compound ; by it the number and kind of atoms of which the molecule of a substance is made up are indicated. The simplest kind of formula are what are known as empirical formulce, which indicate only the kind and number of atoms which form the compound. Thus, HC1 indicates a mole- cule composed of one atom of hydrogen united with one atom of chlorine ; 5H20, five molecules, each composed of two atoms of hydrogen and one atom of oxygen, the number of molecules being indicated by the proper numeral placed before the formula, in which place it applies to all the symbols following it. Sometimes it is desired that a numeral shall apply to a part of the symbols only, in which case they are enclosed in parenthe- ses ; thus, (S04)3A12 means 3 times S04 and twice A3. For other varieties of formulae, see p. 25. Equations are combinations of formulae and algebraic signs so arranged ELECTROLYSIS. 17 as to indicate a chemical reaction and its results. The signs used are the plus and equality signs; the former being equivalent to “and,” and the second meaning “have reacted upon each other and have produced.” The substances entering into the reaction are placed before the equality sign, and the products of the reaction after it; thus, the equation 2KH0 + S04H2 = S04K3 + 2Ha0 means, when translated into ordinary language : two molecules of potash, each composed of one atom of potassium, one atom of hydrogen and one atom of oxygen, and one molecule of sulphuric acid, composed of one atom of sulphur, four atoms of oxygen, and two atoms of hydrogen, have reacted upon each other and have produced one molecule of potassium sulphate, composed of one atom of sulphur, four atoms of oxygen, and two atoms of potassium, and two molecules of water, each composed of two atoms of hydrogen and one atom of oxygen. As no material is ever lost or created in a reaction, the number of each kind of atom occurring before the equality sign in an equation must al- ways be the same as that occurring after it. Electrolysis. When a galvanic current of sufficient power is made to pass through a compound liquid, or a solution of a compound capable of conducting the current, a decomposition of the compound almost invariably ensues. Fig. 6. The terminals by which the current is conducted into the liquid are known as the poles or electrodes, and for this purpose are best made of sheets of platinum. The pole connected with the copper, carbon, or platinum 18 MANUAL OF CHEMISTRY. end of the battery is known as the positive pole ; that connnected with the zinc end as the negative pole. The decomposition by the voltaic current is known as electrolysis, and the liquid subjected to decomposition is called an electrolyte. When compounds are subjected to electrolysis the constituent ele- ments are not discharged throughout the mass, although the decomposition occurs at all points between the electrodes. In compounds made up of two elements only, binary compounds, one element is given off at each of the poles, entirely unmixed with the other, and always from the same pole. Thus, if hydrochloric acid be subjected to electrolysis in the apparatus shown in Fig. 6, pure hydrogen is given off at the negative pole and pure chlorine at the positive pole. In the case of compounds containing more than two elements, a simi- lar decomposition occurs ; one element being liberated at one pole and the remaining group of elements separating at the other. This primary decomposition is frequently modified as to its final products by intercur- rent chemical reactions; indeed, the group of elements liberated at one pole is rarely capable of separate existence. When, for instance, a solution of potassium sulphate is subjected to electrolysis in the apparatus figured above, the liquid in the arm of the tube connected with the positive pole becomes acid in reaction, and gives off oxygen ; at the same time the liquid on the negative side becomes alkaline and gives off a volume of hy- drogen double that of the oxygen liberated. In the first place, the potas- sium sulphate molecule is decomposed into potassium and the group S04: so4k2 = so4+e:2. The potassium liberated at the negative pole immediately decomposes the surrounding water, forming potash and liberating hydrogen : K2 -f 2H20 = 2KHO + H2. The group S04 liberated at the positive pole immediately reacts with water to form sulphuric acid and liberates oxygen : so4+h2o = so4h2+o. In the electrolysis of chemical compounds the different elements and groups of elements, such as S04 in the example given above, known as residues or radicals, seem to be possessed of definite electrical characters, and are given off at one or the other pole in preference. Those which are given off at the positive or platinum pole are supposed to be negatively electrified, and are therefor known as electro-negative or acidulous ele- ments or residues; those given off at the negative pole, being positively electrified, are known as electro-positive or basylous elements or residues. The following are the electrical characters of the principal elements and residues: Electro-negative or Acidulous. Electro-positive or Basylous. Oxygen, Sulphur, Nitrogen, Chlorine, Iodine, Fluorine, Molybdenum, Tungsten, Boron, Carbon, Antimony, Tellurium, Hydrogen, Potassium, Sodium, Lithium, Barium, Strontium, Nickel, Cobalt, Cerium, Lead, Tin, Bismuth, ACIDS, BASES, AND SALTS. 19 Electro-neoative or Acidulous. Electbo-positive or Basylous. Phosphorus, Selenium, Arsenic Chromium, Niobium, Titanium, Silicon, Osmium, Calcium, Uranium, Magnesium, Copper, Glucinium, Silver, Yttrium, Mercury, Aluminium, Palladium, Zirconium, Platinum, Manganese, Rhodium, Zinc, Iridium, Cadmium, Gold, Iron, Alcoholic radicals. Residues of acids remaining after the removal of a number of hydro- gen atoms equal to the basicity of the acid. Acids, Bases, and Salts. An acid is a compound of an electro-negative element or residue vrith hy- drogen ; which hydrogen it can part with in exchange for an electro-positive element or radical. An acid may also be defined as a compound body which evolves water by its action upon pure caustic potash or soda. No substance which does not contain hydrogen can, therefor, be called an acid. The basicity of an acid is the number of replaceable hydrogen atoms con- tained in its molecule. A monobasic acid is one containing a single replaceable atom of hy- drogen, as nitric acid, N03H; a dibasic acid is one containing two such replaceable atoms, as sulphuric acid, S04H„; a tribasic acid is one contain- ing three replaceable hydrogen atoms, as phosphoric acid, P04H3. Poly- basic acids are such as contain more than one atom of replaceable hy- drogen. Hydracids are acids containing no oxygen ; oxacids or oxyacids contain both hydrogen and oxygen. The term base is regarded by many authors as applicable to any com- pound body capable of neutralizing an acid ; it is, however, more consist- ent with modern views to limit the application of the name to such compound substances as are capable of entering into double decomposition with acids to form salts and water. They may be considered as one or more molecules of water in which one-half of the hydrogen hae- been re- placed by an electro-positive element or radical; or as compounds of such elements or radicals with one or more groups, OH. Being thus consid- ered as derivable from water, they are also known as basic hydrates. They have the general formula Mx (OH)n. They are monoatomic, diatomic, tri- atomic, etc., according as they contain one, two, three, etc., groups oxhy- dryl (OH). A double decomposition is a reaction in which both of the reacting com- pounds are decomposed to form two new compounds, thus: KHO + NOsH = H02 + N03K Potassium hydrate. Nitric acid. Water. Potassium nitrate. Sulphobases, or hydrosulphides, are compounds in all respects resem- bling the bases, except that in them the oxygen of the base is replaced by sulphur. Salts are substances formed by the substitution of basylous radicals or ele- ments for a part or all of the replaceable hydrogen of an acid. They are 20 MANUAL OF CHEMISTRY. always formed, therefor, when bases and acids enter into double decompo- sition. They are not, as was formerly supposed, formed by the union of a metallic with a non-metallic oxide, but, as stated above, by the substitu- tion of one or more atoms of an element or radical for the hydrogen of the acid. Thus, the compound formed by the action of sulphuric acid upon quicklime is not S03Ca0, but S04Ca, formed by the interchange of atoms: S o. < (Ca H. > O and not O. < {? <-$ it is, therefor, calcium sulphate, and not sulphate of lime. The term salt, as used at present, applies to the compound formed by the substitution of another element for the hydrogen of any acid ; and in- deed, as used by some authors, to the acids themselves, which are con- sidered as salts of hydrogen. It is probable, however, that eventually the name will be limited to such compounds as correspond to acids whose molecules contain more than two elements. Indeed, from the earliest times of modern chemistry a distinction has been observed between the haloid salts, i.e., those the molecules of whose corresponding acids con- sisted of hydrogen united with one other element, on the one hand ; and the salts of the oxacids, i.e., those into whose composition oxygen en- tered, on the other hand. This distinction, howrever, has gradually fallen into the background, for the reason that the methods and conditions of formation of the two kinds of salts are usually the same when the basylous element belongs to that class usually designated as metallic. There are, however, important differences between the two classes of compounds. There exist compounds of all of the elements correspond- ing to the hydracids, binary compounds of chlorine, bromine, iodine, and sulphur. There is, on the other hand, a large class of elements which are incapable of forming salts corresponding to the oxacids ; no salt of an oxacid with any one of the elements usually classed as metalloids (except- ing hydrogen) has been obtained. Haloid salts can be formed either by displacement of the hydrogen of the corresponding acid, or by direct union of the elements: 2HC1 + Na2 = NaCl + H2, or Na2 + Cl3 = 2 NaCl Oxysalts are formed either by the action of a basylous element or its hydrate or oxide on the acid; by direct union of the basic oxide and anhydride, by double decomposition, or by oxidation of a lower com- pound : S04H3-f K„ = S04K2+H., S04H2 + KH0 = SO K2 + 2H„0 so4h2+k2o = SQ4K2+H20‘ so3+k2o = so4k2 S04H2 + 2N03K = S04K3 + 2N03H K2S + 20 = S04K2 As in the formulae of the organic acids it is customary and convenient to place the replaceable hydrogen atoms at the right hand end of the for- ACTION OF ACIDS AND BASES ON SALTS. 21 mula, e.g., C2H402H, we consider the method of French and German authors of writing the formulae of the oxacids and their salts in the same way, e.g., S04H2 ; P04K3, as far preferable to the English and American method of writing them in the opposite way, H2 S04; K3 P04. In the case of the haloid salts there is not that close connection between the acid and salt, and, therefor, the distinction marked by writing their formulae in the opposite way, e.g., HC1; NaCl is to be desired. Oxides and Hydrates. All the elements, except fluorine, unite with oxygen in one or more proportions to form one or more oxides which are capable of uniting with water. Acid oxides, or anhydrides are those ivhose corresponding hydrates are acids. Thus, sulphuric anhydride, S03, unites with water to form sulphuric acid, S04H2. Basic oxides are those whose hydrates are bases. Thus calcium oxide, CaO, unites with water to form calcium hydrate, CaH202. Saline, neutral, or indifferent oxides are compounds formed by the union of two other oxides. Thus manganoso-manganic oxide, Mn304, is a compound of manganous oxide, MnO, and manganic oxide, Mn203. Action of Acids and Bases on Salts, and of Salts on each other. If an acid be added to a solution of a salt whose acid it nearly equals in chemical activity, the salts of both acids and the free acids themselves will probably exist in the solution, provided both acids and salts are solu- ble. Thus : 2S04H2 + 3N03K; = S04K2 + N03K + S04H2 + 2N03H Sulphuric acid. Potassium nitrate. Potassium sulphate. Potassium nitrate. Sulphuric acid. -Nitric acid. If an acid be added to a solution of a salt whose acid it greatly exceeds in activity, the salt is decomposed, with formation of the salt of the stronger acid, and liberation of the weaker acid ; both acids and salts being soluble : S04H2 4- 2C2H302Na = S04Na2 + 2C2H302H Sulphuric acid. Sodium acetate. Sodium sulphate. Acetic acid. If to a solution of a salt whose acid is insoluble in the solvent used, an acid be added capable of forming a soluble salt with the basylous element, such soluble salt is formed and the acid is deposited : S04H2 + 2C18H3ANa = S04Na2 + 2C18H3602H If, to a salt whose acid is volatile at the existing temperature, an acid, capable of forming with the basylous element a salt fixed at the same temperature, be added, the fixed salt is formed and the volatile acid ex- pelled. Thus, with the application of heat: Sulphuric acid. Sodium stearate. Sodium sulphate. Stearic acid. S04H2 + 2N03Na = S04Na2 + 2NOsH Sulphuric acid. Sodium nitrate. Sodium sulphate. Nitric acid. 22 MANUAL OF CHEMISTRY. If to a solution of a salt an acid be added which is capable of forming an insoluble salt with the base, such insoluble salt is formed and precipi- tated : S04H2 + (N03)2Ba = S04Ba + 2N03H If to a solution of a salt whose basylous element is insoluble, a soluble base is added, capable of forming a soluble salt with the acid, such soluble salt is formed, with precipitation of the insoluble base : Sulphuric acid. Barium nitrate. Barium sulphate. Nitric acid. S04Cu + 2KHO = S04K2 + CuH202 Cupric sulphate. Potassium hydrate. Potassium sulphate. Cupric hydrate. If a base be added to a solution of a salt with whose acid it is capable of forming an insoluble salt, such insoluble salt is formed and precipitated, and the base of the original salt, if insoluble, is also precipitated: Barium hydrate. BaH202 + S04K2 = S04Ba + 2KHO Potassium sulphate. Barium sulphate. Potassium hydrate. BaH202 + S04Ag2 = S04Ba + 2AgHO Barium hydrate. Silver sulphate. Barium sulphate. Silver hydrate. When solutions of two salts, the acids of both of which form soluble salts with both bases, are mixed, the resultant liquid contains the four salts : 3S04K2 + 3N03Na = 2S04K2 + S04Na2 + 2N03K + NOsNa Potassium sulphate. Sodium nitrate. Potassium sulphate. Sodium sulphate. Potassium nitrate. Sodium nitrate. or in some other proportion. If solutions of two salts the acid of one of which is capable of uniting with the base of the other to form an insoluble salt, are mixed, such in- soluble salt is precipitated: Barium nitrate. (N03)2Ba + S04Na2 = S04Ba + 2NOsNa Sodium sulphate. Barium sulphate. Sodium nitrate. Nomenclature. The names of the elements are mostly of Greek derivation, and have their origin in some prominent property of the substance ; thus, phos- phorus, ws, light, and 4>epeLv, to bear. Some are of Latin origin, as silicon, from silex, flint ; some of Gothic origin, as iron, from iarn ; and others are derived from modern languages, as potassium, from pot-ash. Very little system has been followed in naming the elements, beyond applying the termination ium to the metals, and ine or on to the metalloids ; and even to this rule we find such exceptions as a metal called manganese and a metalloid called sulphur. The names of compound substances were formerly chosen upon the same system, or rather lack of system, as those of the elements. So long as the number of compounds with which the chemist had to deal remained small, the use of these fanciful appellations, conveying no more to the mind than perhaps some unimportant quality of the substances to which they applied, gave rise to comparatively little inconvenience. In these NOMENCLATURE. later days, however, when the number of compounds has risen high in the thousands, some systematic method has become absolutely necessary. The principle at the base of the system of nomenclature at present used is that the name shall itself convey, as far as possible, the composition and character of the substance. Compounds consisting of two elements, or of an element and a radical only, binary compounds, are designated by compound names made up of the name of the more electro-positive, followed by that of the more elec- tro-negative, in which the termination ide has been substituted for the terminations ine, on, ogen, ygen, orus, ium, and ur. For example : the compound of potassium and chlorine is called potassium chloride, that of potassium and oxygen, potassium oxide, that of potassium and phos- phorus, potassium phosphide. In a few instances the older name of a compound is used in preference to the one which it should have under the above rule, for the reason that the substance is one which is typical of a number of other substances, and therefor deserving of exceptional prominence ; such are ammonia, NH3; water, H20. When, as frequently happens, two elements unite with each to form more than one compound, these are usually distinguished from each other by prefixing to the last word of the name the Greek numeral correspond- ing to the number of atoms of the element designated by that word, as compared with a fixed number of atoms of the other element. Thus, in the series of compounds of nitrogen and oxygen, most of which contain two atoms of nitrogen, N2 is the standard of comparison, and consequently the names are as follows : N,,0 =Nitrogen monoxide. NO (=N202)=Nitrogen dioxide. N203 = Nitrogen trioxide. N„0 (=N204):=Nitrogen fe/roxide. N205 = Nitrogen pentoxide. Another method of distinguishing two compounds of the same two elements consists in terminating the first word in ous, in that compound which contains the less proportionate quantity of the more electro-nega- tive element, and in ic in that containing the greater proportion ; thus : S02=Sulphurous oxide. S03=Sulphuric oxide. Hg2Cl2 (2Hg : 2C1) = Mercurous chloride. HgCl2 (2Hg : 4C1)=Mercuric chloride. This method, although used to a certain extent in speaking of compounds composed of two elements of Class II. (see p. 29), is used chiefly in speak- ing of binary compounds of elements of different classes. In naming the oxacids the word acid is used, preceded by the name of the electro-negative element other than oxygen, to which a prefix or suffix is added to indicate the degree of oxidation. If there be only two, the least oxidized is designated by the suffix ous, and the more oxidized by the suffix ic, thus : NO„H = Nitrous acid. NOaH = Nitric acid. 24 MANUAL OF CHEMISTRY. If there be more than two acids, formed in regular series, the least oxi- dized is designated by the prefix hypo and the suffix ous; the next by the suffix ous ; the next by the suffix ic ; and the most highly oxidized by the prefix per and the suffix ic ; thus : ClOH = Hypochlorous acid. C102H = Chlorous acid. C103H = Chloric acid. C104H = Perchloric acid. Certain elements, such as sulphur and phosphorus, exist in acids which are derived from those formed in the regular way, and which are specially designated. The names of the oxysalts are derived from those of the acids by drop- ping the word acid, changing the termination of the other word from ous into ite, or from ic into ate, and prefixing the name of the electro-positive element or radical; thus: so3h2 sosK, Sulphurous acid. Potassium sulphite. SO.H, SO.K, Sulphuric acid. Potassium sulphate. ClOH ClOK Hypochlorows acid. Potassium hypochlorite. Acids whose molecules contain more than one atom of replaceable hy- drogen are capable of forming more than one salt with electro-negative elements, or radicals, whose valence is less than their basicity. Ordinary phosphoric acid, for instance, contains in each molecule three atoms of basic hydrogen, and consequently is capable of forming three salts by the replacement of one, two, or three of its hydrogen atoms by one, two, or three atoms of a univalent element; to distinguish these the Greek prefixes mono, di, and tri are used, thus: P04H,,K = il/onopotassic phosphate. P04HIv2 =. Dipotassic phosphate. P04K3 = Tripotassic phosphate. The first is also called rfiAyciropotassic phosphate, and the second hydrodi- potassic phosphate. In the older works, salts in which the hydrogen has not been entirely displaced are sometimes called bisalts (bicarbonates), or acid salts ; those in which the hydrogen has been entirely displaced being designated as neutral salts. Some elements, such as mercury, copper, and iron, form two distinct series of salts ; these are distinguished, in the same way as the acids, by the use of the suffix ous in the names of those containing the less propor- tion of electro-negative group, and the suffix ic in those containing the greater proportion, e.g.: S04(Cu2)3 (1S04 : 4Cu) = Cuprous sulphate. S04 Cu2 (2S04 : 4Cu) = Cupric sulphate. S04Fe (2S04 : 2Fe) = Ferrous sulphate. (S04)3Fe2 (3S04 : 2Fe) = Ferric sulphate. CONSTITUTION’. TYPICAL AND GRAPHIC FORMULAE. 25 The names, basic salts, sw&salts, and oaysalts have been applied in- differently to salts, such as the lead subacetates, which are compounds containing the normal acetate and the hydrate or oxide of lead ; and to salts such as the so-called bismuth subnitrate, which is a nitrate, not of bismuth, but of the univalent radical (Bi"'0")'. By double salts are meant such as are formed by the substitution of different elements or radicals for two or more atoms of replaceable hydro- gen of the acid, such as ammonio-magnesian phosphate, P04Mg" (NH4)'. Radicals. A radical, or compound radical, is a non-saturatea group of atoms which behaves like an atom of an element. Such radicals are capable of passing from one compound into another, and are sometimes, although rarely, cap- able of separate existence. Marsh gas has the composition CH4 ; by act- ing upon it in suitable ways we can cause the atom of carbon, accompanied by three of the hydrogen atoms, to pass into a variety of other compounds, such as : (CHJCl; (CHJOH ; (CH3)20 ; C2H302(CH3). Marsh gas, there- for, consists of the radical (CH3) combined with an atom of hydrogen: (CHJ'H. It is especially among the compounds of carbon that the existence of radicals comes into prominent notice ; they, however, occur in inorganic substances also ; thus the nitric acid molecule consists of the radical N02, combined with the group OH. Like the elements, the radicals possess different valences, depending always upon the number of unsatisfied valences which they contain. Thus the radical (CH3) is univalent, because three of the four valences of the carbon atom are satisfied by atoms of hydrogen, leaving one free valence ; the radical (PO) of phosphoric acid is trivalent, because two of the five valences of the phosphorus atom are satisfied by the two valences of the bivalent oxygen atom, leaving three free valences. In notation the radicals are usually enclosed in brackets, as above, to indicate their nature. The names of radicals terminate in yl or in gen ; thus : (CHa) = methyl; (CN) = cyanogen. The terms radical and residue, although sometimes used as synonyms, are not such in speaking of electrical decompositions (see p. 18). Thus the radical of sulphuric acid is S03; but when sulphuric acid is electrolyzed it is decomposed into hydrogen and the residue S04. Constitution. Typical and Graphic Formulae. The composition of a compound is the number and kind of atoms con- tained in its molecule ; and is shown by its empirical formula. The constitution of a compound is the number and kind of atoms and their relations to each other, within its molecule ; and is shown by its typical or graphic formula. The characters of a compound depend not only upon the kind and number of its atoms, but also upon the manner in which they are attached to each other, upon their constitution. There are, for instance, two sub- stances, each having the empirical formula C2H402, one of which is a strong acid, the other a neutral ether. As the molecule of each contains the same number and kind of atoms, the differences in their properties 26 MANUAL OF CHEMISTRY. must be due to differences in the manner in which the atoms are linked together. In the system of typical formulae all substances are considered as being so constituted that their rational formulas may be referred to one of .three classes or types, or to a combination of two of these types. These three classes, being named after the most common substance occurring in each, are expressed thus : The hydrogen type. The water type. The ammonia type. H H S}° H) H >- N H 5} etc., H4o H,) °> HJ h;[ ’ etc., etc., it being considered that the formula of any substance of known consti- tution can be indicated by substituting the proper element, or radical, for one or more of the atoms of the type, thus : 3} (°Ah}° mv) HVN h) C14 Caj (SO,)"} HJO, (GO)") h5n, HJ Hydrochloric acid. Alcohol. Ethylamine. Calcium chloride. Sulphuric acid. Urea. Typical formulre are of great service in the classification of compound substances, as well as to indicate, to a certain degree, their nature and the method of the reactions into which they enter. Thus in the case of the two substances mentioned above as both having the composition c2h4o2, we find on examination that one contains the group (CHS)', while the other contains the group (C2H30)', united to one atom of replaceable hydrogen. The difference in their constitution at once becomes apparent in their typical formula?, j O and j C> indicating differ- ences in their properties, which we find upon experiment to exist. The first substance is neutral in reaction and possesses no acid properties ; it closely resembles a salt of an acid having the formula j O. The second substance, on the other hand, has a strongly acid reaction, and markedly acid properties, as indicated by the oxidized radical and the extra-radical hydrogen. It is capable of forming salts by the substitution of an atom of a univalent, basylous element for its single replaceable atom of hydrogen : (C2H30)') Q Na j Although typical formulae have been, and still are, of great sendee, many cases arise, especially in treating of the more complex organic sub- stances, in which they do not sufficiently indicate the relations between the atoms which constitute the molecule, and thus fail to convey a proper idea of the nature of the substance. Considering, for example, the ordi- nary lactic acid, wre find its composition to be C Hc03, which, expressed (G H 01" ) typically, would be ' 3 4 pj- j 02, a constitution supported by the fact CONSTITUTION. TYPICAL AND GRAPHIC FORMULAE. that the radical (C3H40)' may be obtained in other compounds, as ' 3 4 q f • This constitution, however, cannot be the true one, because in the first place, lactic acid is not dibasic, but monobasic ; and, in the second place, there is another acid, called paralactic acid, having an iden- tical composition, yet differing in its products of decomposition. These differences in the properties of the two acids must be due to a different arrangement of atoms in their molecules, a view which is supported by the sources from which they are obtained and the nature of their products of decomposition. To express the constitution of such bodies, graphic formulce are used, in which the position of each atom in relation to the others is set forth. The constitution of the two lactic acids would be expressed by graphic formulae in this way : /H C—H ,,/H I \0—H u\0—H /H C—H \0—H 0/H | \H u\0—H and or, CH3 I CH.OH I CO.OH Ordinary lactic acid. ch2oh I fH’ CO.OH Paralactic acid. and It must be understood that these graphic formula are simply in- tended to show the relative attachments of the atoms, and are in nowise intended to convey the idea that the molecule is spread out upon a flat surface with the atoms arranged as indicated in the diagram. Great care and much labor are required in the construction of these graphic formulae, the positions of the atoms being determined by a close study of the methods of formation, and of the products of decomposition of the substance under consideration. Naturally, in a matter of this na- ture, there is always room for differences of opinion—indeed, the entire atomic theory is open to question, as is the theory of gravitation itself. But, whatever may be advanced, two facts cannot be denied: first, that chemistry owes its advancement within the past half-century to the atomic theory, which to-day is more in consonance with observed facts than any substitute which can be offered ; second, that without the use of graphic formulas it is impossible to offer any adequate explanation of the reac- tions which we observe in dealing with the more complex organic sub- stances. In chemistry, as in other sciences, a sharp distinction must always be made between facts and theory: the former, once observed, are immut- able additions to our knowledge ; the latter are of their nature subject to change with our increasing knowledge of facts. We have every reason for believing, however, that the supports upon which the atomic theory 28 MANUAL OF CHEMISTRY. rests are such that, although it may be modified in its details, its essential features will remain unaltered. Classification of the Elements. Berzelius was the first to divide all the elements into two great classes, to which he gave the names metals and metalloids. The metals, being such substances as are opaque, possess what is known as metallic lustre, are good conductors of heat and electricity, and are electro-positive ; the metal- loids, on the other hand, such as are gaseous, or, if solid, do not possess metallic lustre, have a comparatively low power of conducting heat and electricity, and are electro-negative. This division, based purely upon physical properties, which, in many cases, are ill-defined, has become insufficient. Several elements formerly classed under the above rules with the metals, resemble the metalloids in their chemical characters much more closely than they do any of the metals; indeed, by the characters mentioned above, it is impossible to draw any line of demarcation which shall separate the elements distinctly into two groups. The classification of the elements should be such that each group shall contain elements whose chemical properties are similar—the physical prop- erties being considered only in so far as they are intimately connected with the chemical (see p. 14). The arrangement of elements into groups is not equally easy in all cases ; some groups, as the chlorine group, are sharply defined, while the members of others differ from each other more widely in their properties. The positions of most of the more recently discovered elements are still uncertain, owing to the imperfect state of our knowledge of their properties. The method of classification which we will adopt, and which we be- lieve to be more natural than any hitherto suggested, is based upon the chemical properties of the oxides and upon the valence of the elements. We abandon the division into metals and metalloids, and substitute for it a division into four great classes, according to the nature of the oxides and the existence or non-existence of oxysalts. In the first of these classes hydrogen and oxygen are placed together, for the reason that, although they differ from each other in many of their properties, they together form the basis of our classification, and may, for this and other reasons, be regarded as typical elements. They both play important parts in the formation of acids, and neither wrould find a suitable place in either of the other classes. Our primary division would then be as follows : Class I.—Typical elements. Class II.—Elements whose oxides unite with water to form acids, never to form bases. Which do not form oxysalts. This class contains all the so-called metalloids except hydrogen and oxygen. Class III.—Elements whose oxides unite with water, some to form bases, others to form acids. Which form oxysalts. Class IV.—Elements ivhose oxides unite with ivater to form bases; never to form acids. Which form oxysalts. In this class are included the more strongly electro-positive metals. Within the classes a further subdivision is made into groups, each group containing those elements within the class which have equal va- PHYSICAL CHARACTERS OF CHEMICAL INTEREST. 29 lences, which form corresponding compounds, and whose chemical charac- ters are otherwise similar. For the sake of convenience the term metal is retained to apply to the members of Classes IH. and IV.; the term non-metal being used for those belonging to Class H. Class I. Group I.—Hydrogen. Group H.—Oxygen. Class II. Group I.—Fluorine, chlorine, bromine, iodine. Group II.—Sulphur, selenium, tellurium. Group III.—Nitrogen, phosphorus, arsenic, antimony. Group IV.—Boron. Group V.—Carbon, silicon. Group VI.—Vanadium, niobium, tantalium. Group VII.—Molybdenum, tungsten, osmium (?). Class in. Group I. —Gold. Group II.—Chromium, manganese, iron. Group III.—Glucinium, aluminium, scandium, gallium, indium. Group IV.—Uranium. Group V.—Lead. Group VI.—Bismuth. Group VII.—Titanium, zirconium, tin. Group V11L—Palladium, platinum. Group IX.—Rhodium, ruthenium, iridium. Class IV. Group I.—Lithium, sodium, potassium, rubidium, ccesium, silver. i Group II.—Thallium. Group III.—Calcium, strontium, barium. Group IV.—Magnesium, zinc, cadmium. Group V.—Nickel, cobalt. Group VI.—Copper, mercury. Group VII.—Yttrium, cerium, ytterbium, lanthanium, didymium, er- bium. Group VHI.—Thorium. Physical Characters of Chemical Interest. Crystallization.—Solid substances exist in two forms, amorphous and crystalline. In the former they assume no definite shape ; they con- duct heat equally well in all directions ; they break irregularly ; and, if transparent, allow light to pass through them equally well in all direc- tions. A solid in the crystalline form has a definite geometrical shape ; conducts heat more readily in some directions than in others ; when 30 MANUAL OF CHEMISTRY. broken, separates in certain directions, called planes of cleavage, more readily than in others; and modifies the course of luminous rays passing through it differently when they pass in certain directions than when they pass in others. Crystals are formed in one of four ways : 1.) An amorphous substance, Fig. 7. by slow and gradual modification, may assume the crystalline form ; as vitreous arsenic trioxide (q. v.) passes to the crystalline variety. 2.) A fused solid, on cooling, crystallizes ; as bismuth. 3.) When a solid is sub- limed it is usually condensed in the form of crystals. Such is the case with arsenic trioxide. 4.) The usual method of obtaining crystals is by the evaporation of a solution of the substance. # If the evaporation be slow and the solution at rest, the crystals are large and well-defined. If the crystals separate by the sudden cooling of a hot solution, especially if it be agitated during the cooling, they are small. Most crystals may be divided by imaginary planes into equal, symmet- rical halves ; such planes are called planes of symmetry. Thus in the crystals in Fig. 7 the planes ab ab, ac ac, and be be are planes of symmetry. When a plane of symmetry contains two or more equivalent linear directions passing through the centre, it is called the principal plane of symmetry ; as in Fig. 8 the plane ab ab, containing the equal linear direc- tions aa and bb. Fig. 8. Any normal erected upon a plane of symmetry, and prolonged in both directions until it meets opposite parts of the exterior of the crystal, at equal distances from the plane, is called an axis of symmetry. The axis normal to the principal plane is the principal axis. Thus in Fig. 8, aa, bb, and cc are axes of symmetry, and cc is the principal axis. PHYSICAL CHARACTERS OF CHEMICAL INTEREST. 31 Upon the relations of these imaginary planes and axes a classification of all crystalline forms into six systems has been based. I. The Cubic, Regular, or Monometric System.—The crystals of this system have three equal axes, aa, bb, cc, Fig. 7, crossing each other at right angles. The simple forms are the cube ; and its derivatives, the octahedron, tetrahedron, and rhombic dodecahedron. The crystals of this system expand equally in all directions when heated, and are not doubly refracting. II. The Right Square Prismatic, Pyramidal, Quadratic, Tetragonal, or Dimetric System contains those crystals having three axes placed at right angles to each other—two as aa and bb, Fig. 8, being equal to each other and the third, cc, either longer or shorter. The simple forms are the right square prism and the right square based octahedron. The crystals of this system expand equally only in two directions when heated ; they Fig. 9. refract light doubly in all directions except through one axis of single re- fraction. m. The Rhombohedral or Hexagonal System includes crystals hav- ing four axes, three of which aa, aa, aa, Fig. 9, are of equal length and cross each other at 60° in the same plane ; to which plane the fourth axis, cc, longer or shorter than the others, is at right angles. The simple forms are the regular nix-sided prism, the regular dodecahedron, the rhombohedron, and the scalenohedron. These crystals expand equally in two directions when heated, and refract light singly through the principal axis, but in other directions refract it doubly. IV. The Rhombic, Right Prismatic, or Trimetric System.—The axes of crystals of this system are three in number, all at right angles to each other, and all of unequal length. Fig. 8 represents crystals of this system, supposing aa, bb, and cc to be unequal to each other. The simple forms are the right rhombic octahedron, the right rhombic prism, the right rectangu- lar octahedron, and the right rectangular prism. The crystals of this system, like those of the two following, have no true principal plane or axis. V. The Oblique, Monosymmetric, or Monoclinic System.—The crystals of this system have three axes, two of which, aa, and cc, Fig. 10, are at 32 MANUAL OF CHEMISTKY. right angles; the third, bb, is perpendicular to one and oblique to the other ; they may be equal or all unequal in length. The simple forms are the oblique rectangular and oblique rhombic prism and octahedron. VI. The Doubly Oblique, Asymmetric, Triclinic, or Anorthic System contains crystals having three axes of unequal length, crossing each other Pig. 10. at angles not right angles ; Fig. 10, aa, bb, and cc being unequal and the angles between them other than 90°. The crystals of the fourth, fifth, and sixth systems, when heated, ex- pand equally in the directions of their three axes ; they refract light doubly except in two axes. Secondary Forms.—The crystals occurring in nature or produced arti- ficially have some one of the forms mentioned above, or some modification Pig. 11. of those forms. These modifications or secondary forms may be produced by symmetrically removing the angles or edges, or both angles and edges, of the primary forms ; thus, by progressively removing the angles of the cube, the secondary forms shown in Fig. 11 are produced. It sometimes happens in the formation of a derivative form that alter- nate faces are excessively developed, producing at length entire oblitera- tion of the others, as shown in Fig. 12. Such crystals are said to be Fig. 12. hemihedral; they can be developed only in a system having a principal axis. Isomobphism.—In many instances two or more substances crystallize in forms identical with each other, and, in most cases, such substances re- semble each other in their chemical constitution ; they are said to be 33 PHYSICAL CHARACTERS OF CHEMICAL INTEREST. isomorphous. This identity of crystalline form does not depend so much upon the nature of the elements themselves, as upon the structure of the molecule. The protoxide and peroxide of iron do not crystallize in the same form, nor can they be substituted for each other in reactions with- out radically altering the properties of the resultant compound. On the other hand, all that class of salts known as alums are isomorphous ; not only are their crystals identical in shape, but a crystal of one alum, placed in a saturated solution of another, grows by regular deposition of the second upon its surface. Other alums may be subsequently added to the crystal, a section of which will then exhibit the various salts, layer upon layer. Dimorphism.—Although most substances crystallize, if at all, in one simple form or in some of its modifications, a few bodies are capable of assuming two crystalline forms belonging to different systems ; such are said to be dimorphous. Thus, sulphur, as obtained by the evaporation of its solution in carbon disulphide, forms octahedra belonging to the fourth system ; when obtained by cooling melted sulphur, the crystals are oblique prisms, belonging to the fifth system. Occasional instances of trimor- phism, of the formation of crystals belonging to three different systems by the same substance, are also known. Allotropy.—Dimorphism apart, a few substances are known to exist in more than one solid form. These varieties of the same substance ex- hibit different physical properties, while their chemical qualities are the same in kind. Such modifications are said to be allotropic. One or more allotropic modifications of a substance are usually crystalline, the other or others amorphous or vitreous. Sulphur, for example, exists not only in two dimorphous varieties of crystals, but also in a third, allotropic form, in which it is flexible, amorphous, and transparent. Carbon exists in three allotropic forms : two crystalline, the diamond and graphite ; the third amorphous. In passing from one allotropic modification to another, a substance absorbs or gives out heat. Solution.—A solid, liquid, or gas is said to dissolve, or form a solution with a liquid when the two substances unite to form a homogeneous liquid. Solution may be a purely physical process or a chemical combination. In simple or physical solution there is no modification of the properties of the solvent and dissolved substance, beyond the liquefaction ; the latter can be regenerated in its primitive form by simple evaporation of the former; and the act of solution is attended by a diminution of temperature. In chemical solution the properties of both solvent and dissolved are more or less modified; the dissolved substance can not be obtained from the solution by simple evaporation of the solvent, unless the compound formed be decomposable, with formation of the original substance, at the tempera- ture of the evaporation. The act of chemical solution is attended by an elevation of temperature. The amount of solid, liquid, or gas which a liquid is capable of dissolv- ing by simple solution depends upon the following conditions : 1. The nature of the solvent and substance to be dissolved.—No rule can be given which will apply in a general way to the solvent power of liquids or the solubility of substances. Water is of all liquids the best solvent of most substances ; in it some substances are so readily soluble that they absorb a sufficiency from the atmosphere to form a solution ; as calcium chloride. Such substances are said to be deliquescent. Other substances are insoluble in water in any proportion ; as barium sulphate. Elemen- 34 MANUAL OF CHEMISTRY. tary substances are insoluble, or sparingly soluble, in water. Substances rich in carbon are insoluble in water, but soluble in organic liquids. 2. The temperature has a marked influence on the solubility of a sub- stance. As a rule, water dissolves a greater quantity of a solid substance as the temperature is increased. This increase in solubility is different in the case of different soluble substances ; thus the increase in solubility of the chlorides of barium and of potassium is directly in proportion to the increase of temperature; the solubility of sodium chloride is almost imperceptibly increased by elevation of temperature ; the solubility of sodium sulphate increases rapidly up to 33° (91°.4 F.), above which tem- perature it again diminishes. The solubility of gases in water is the greater the lower the tempera- ture and the higher the pressure. The amount of a substance that a given quantity of solvent is capable of dissolving at a given temperature is fixed. A solution containing as much of the dissolved substance as it is capable of dissolving is said to be saturated ; if made at high temperatures it is said to be a hot saturated, and if at ordinary temperatures a cold saturated solution. If a hot saturated solution of a salt be cooled, the solid is in most in- stances separated by crystallization. If in the case of certain substances, such as sodium sulphate, however, the solution be allowed to cool while undisturbed, no crystallization occurs, and the solution at the lower tem- perature contains a greater quantity of the solid than it could dissolve at that temperature. Such a solution is said to be supersaturated. The con- tact of particles of solid material with the surface of a supersaturated so- lution induces immediate crystallization, attended with elevation of tem- perature. 3. The presence of other substances already dissolved.—If to a saturated solution of potassium nitrate, sodium chloride be added, a further quan- tity of potassium nitrate may be dissolved. In this case there is double decomposition between the two salts, and the solution contains, besides them, potassium chloride and sodium nitrate. 4. The presence of a second solvent.—If two solvents, a and b, incapable of mixing with each other, be brought in contact with a substance which both are capable of dissolving; neither a nor 6 take up the whole of the substance to the exclusion of the other, however greatly the solvent power or bulk of the one may exceed that of the other. The relative quantities taken up by each solvent is in a constant ratio. Diffusion of Liquids—Dialysis.—If a liquid be carefully floated upon the surface of a second liquid, of greater density, with which it is capable of mixing, two distinct layers will at first be formed. Even at perfect rest, mixture will begin immediately, and progress slowly until the two liquids have diffused into each other to form a single liquid whose density is the same throughout. Substances differ from each other in the rapidity with which they dif- fuse. Substances capable of crystallization, crystalloids, are much more diffusible than those which are incapable of crystallization—colloids. If, in place of bringing two solutions in contact with each other, they be separated by a solid or semi-solid, moist, colloid layer, diffusion takes place in the same way through the interposed layer. Advantage is taken of this fact to separate crystalloids from colloids by the process of dialysis. The mixed solutions of crystalloid and colloid are brought into the inner vessel of a dialyser, Fig. 13, whose bottom consists of a layer of moist parchment paper, while the outer vessel is filled with pure water. Water PHYSICAL CHARACTERS OF CHEMICAL INTEREST. 35 passes into tlie inner vessel, and the crystalloid passes into the water in the outer vessel. By frequently changing the water in the outer vessels, solutions of the albuminoids or of ferric hydrate, etc., almost entirely free from crystalloids, may be obtained. Fig. 13. Specific Heat.—Equal volumes of different substances at the same temperature contain different amounts of beat. If two equal volumes of the same liquid of different temperatures be mixed together, the resulting mixture has a temperature which is the mean between the temperatures of the original volumes. If one litre of water at 4° be mixed with a litre at 38°, the resulting two litres will have a temperature of 21°. Mixtures of equal volumes of different substances, at different temperatures, do not have a temperature which is the mean of the original temperatures of its constituents. A litre of water at 4°, mixed with a litre of mercury at 38°, forms a mixture whose temperature is 27°. Mercury and water, therefor, differ from each other in their capacity for heat. The same difference exists in a more marked degree between equal weights of dissimilar bodies ; if a pound of water at 4° be agitated with a pound of mercury at 70°, both liquids will have a temperature of 67°. The amount of heat required to raise a kilo of water 1° in temperature is a definite quantity. The specific heat of any substance is the amount of heat required to raise one kilo of that substance 1° in temperature, ex- pressed in terms having the amount of heat required to raise a kilo of water 1° as unity. Spectroscopy.—Light in passing through a prism is not only re- fracted into a different course, but is also decomposed or dispersed into different colors, which make up a spectrum. A spectrum is one of three kinds: 1.) Continuous, consisting of a continuous band of colors: red, orange, yellow, green, blue, indigo, and violet. Such spectra are pro- duced by light from white-hot solids and liquids, from gas-light, candle- light, lime-light, and electric light. 2.) Bright-line spectra, composed of bright lines upon a dark ground, are produced by glowing vapors and gases. 3.) Absorption spectra consist of continuous spectra, crossed by dark lines or bands, and are produced by light passing through a solid, liquid, or gas, capable of absorbing certain rays. Examples of bright-line and absorption spectra are shown in Fig. 14. 36 MANUAL OF CHEMISTRY. The spectrum of sun-light belongs to the third class. It is not con- tinuous, but is crossed by a great number of dark lines, known as Fraun- Fig. 14. liofer’s lines, the most distinct of which are designated by letters (No. 1, Fig. 14). The spectroscope consists of four essential parts : 1st, the slit, a, Fig. 15 ; a linear opening between two accurately straight and parallel knife- PHYSICAL CHARACTERS OF CHEMICAL INTEREST. 37 edges. 2d, the collimating lens, b; a biconvex lens in whose principal focus the slit is placed, and whose object it is to render the rays from the slit parallel before they enter the prism. 3d, the prism, or prisms, c, of dense glass, usually of 60°, and so placed that its refracting edge is paral- lel to the slit. 4th, an observing telescope, d, so arranged as to receive the rays as they emerge from the prisms. Besides these parts spectro- scopes are usually fitted with some arbitrary graduation, which serves to fix the location of lines observed. In direct vision spectroscopes a com- pound prism is used, so made up of prisms of different kinds of glass that the emerging ray is nearly in the same straight line as the entering ray. As the spectra produced by different substances are characterized by Fig. 15. the positions of the lines or bands, some means of fixing their location is required. The usual method consists in determining their relation to the principal Fraunhofer lines. As, however, the relative positions of these lines vary with the nature of the substance of which the prism is made, although their position with regard to the colors of the spectrum is fixed, no two of the arbitrary scales used will give the same reading. The most satisfactory method of stating the positions of lines and bands is in wave-lengths. The lengths of the waves of rays of different degrees of refrangibility have been carefully determined, the unit of measurement being the tenth-metre, of which 1010 make a metre. The wave-lengths, = A, of the principal Fraunhofer lines, are : A 7604.00 D 5892.12 G 4307.25 a 7185.00 E 5269.13 H, 3968.01 B 6867.00 b 5172.00 H2 3933.00 C 6562.01 F 4860.72 The scale of wave-lengths can easily be used with any spectroscope having an arbitrary scale, with the aid of a curve constructed by interpo- lation. To construct such a curve, paper is used which is ruled into square inches and tenths. The ordinates are marked with a scale of wave-lengths, and the abscisses with the arbitrary scale of the instrument. The posi- tion of each principal Fraunhofer line is then carefully determined in terms of the arbitrary scale, and marked upon the paper with a x at the 38 MANUAL OF CHEMISTRY. point where the line of its wave-length and that of its position in the ar- bitrary scale cross each other. Through these x a curve is then drawn as regularly as possible. In noting the position of an absorption-band, the position of its centre in the arbitrary scale is observed, and its value in wave-lengths obtained from the curve, which, of course, can only be used with the scale and prism for which it has been made. Polarimetry.—A ray of light passing from one medium into another of different density, at an angle other than 90° to the plane of separation of the two media, is deflected from its course, or refracted. Certain sub- stances have the power, not only of deflecting a ray falling upon them in certain directions, but also of dividing it into two rays, which are pecu- liarly modified. The splitting of the ray is termed double refraction, and the altered rays are said to be polarized. When a ray of such polarized light meets a mirror held at a certain angle, or a crystal of Iceland spar peculiarly cut (a Nichol’s prism), also at a certain angle, it is extinguished. The crystal which produces the polarization is called the polarizer, and that which produces the extinction the analyzer. If, when the polarizer and analyzer are so adjusted as to extinguish a ray passing through the former, certain substances are brought between them, light again passes through the analyzer ; and in order again to pro- duce extinction, the analyzer must be rotated upon the axis of the ray to the right or to the left. Substances capable of thus influencing polarized light are said to be optically active. If, to produce extinction, the analyzer is turned in the direction of the hands of a watch, the substance is said to be dextrogyrous ; if in the opposite direction, Icevogyrous. The distance through which the analyzer must be turned depends upon the peculiar power of the optically active substance, the length of the column interposed,. the concentration if in solution, and the wave-length of the original ray of light. The specific rotary power of a substance is the rotation produced, in degrees and tenths, by one gram of the sub- stance, dissolved in one cubic centimetre of a non-active solvent, and ex- amined in a column one decimetre long. The specific rotary power is determined by dissolving a known weight of the substance in a given vol- ume of solvent, and observing the angle of rotation produced by a column of given length. Then let p = weight in grams of the substance con- tained in 1 c.c. of solution ; l the length of the column in decimetres; a the angle of rotation observed ; and [a] the specific rotary power sought, we have a M = -• pi In most instruments monochromatic light, corresponding to the D line of the solar spectrum, is used, and the specific rotary power for that ray is expressed by the sign [a]D. The fact that the rotation is right-handed is expressed by the sign +, and that it is left-handed by the sign —. It will be seen from the above formula that, knowing the value of [a] D for any given substance, we can determine the weight of that substance in a solution by the formula a p = . [a]D x l The polarimeter or sarcharometer is simply a peculiarly constructed polariscope used to determine the value of [o]d. PART II. SPECIAL CHEMISTRY. CLASS I TYPICAL ELEMENTS. Hydrogen—Oxygen. Although, in a strict sense, hydrogen is regarded by most chemists as the one and only type-element—that whose atom is the unit of atomic and molecular weights—the important part which oxygen plays in the forma- tion of those compounds whose nature forms the basis of our classification, its acid-forming power in organic compounds, and the differences existing between its properties and those of the elements of the sulphur group, with which it is usually classed, warrant us in separating it from the other elements and elevating it to the position it here occupies. HYDROGEN. Symbol = H—Univalent—Atomic weight — 1—Molecular weight = 2— Sp. gr. = 0.06926 A*—One litre weighs 0.0896 gram f—100 cubic inches weigh 2.1496 grains %—1 gram measures 11.19 litres f—1 grain measures 46.73 cubic inches J —Name derived from vSwp = water, and yewaw — I pro- duce—Discovered by Cavendish, in 1766. Occurrence.—Occurs free in volcanic gases, in fire-damp, occluded in meteorites, in the gases exhaled from the lungs, and in those of the stomach and intestine. In combination in water, hydrogen sulphide, am- moniacal compounds, and in many organic substances. Preparation.—(1.) By electrolysis of water, H is given off at the nega- tive pole. Utilized when pure H is required. * Air = 1. When the sp. gr. is referred to H = 1, A is replaced by H. f At 0° C. and 760 mm. barometric pressure, j At 60° F. and 30 inches bar. pressure. 40 MANUAL OF CHEMISTRY. (2.) By the disassociation of water at very high temperatures. (3.) By the decomposition of water by certain metals. The alkaline metals decompose water at the ordinary temperature : Sodium. Nas + 2H20 = 2NaHO + H2 Water. Sodium hydrate. Hydrogen. Some other metals, such as iron and copper, effect the decomposition only at high temperatures : Iron. 3Fe2 + 4H20 = 2Fe304 + 4H2 Water. Triferric tetroxide. Hydrogen. (4.) By decomposition of water, passed over red hot coke : C + 2H20 = C02 + 2H2 Carbon. Water. Carbon dioxide. Hydrogen. or at a higher temperature : Carbon. 2C + 2H20 = 2CO + 2H2 Water. Carbon monoxide. Hydrogen. (5.) By decomposition of mineral acids, in the presence of water, by zinc and certain other metals : Zn + S04H2 + xHfi = S04Zn + H2 + xH.fi Zinc. Sulphuric acid. Water. Zinc sulphate. Hydrogen. Water. What part the water plays m the reaction is still a subject of discus- sion ; it is probable that its action is rather physical than chemical. Chemically pure zinc, or zinc whose surface has been coated with an alloy of zinc and mercury, does not decompose the acid un- less it forms part of a gal- vanic battery whose circuit is closed. The zincs of galvanic batteries are there- for coated with the alloy mentioned — are amalga- mated— to prevent waste of zinc and acid. This method is resorted to for obtaining H ; the gas so obtained is, however, contaminated with small quantities of other gases, hydrogen phosphide, sul- phide, and arsenide. Hydrogen, carbon dioxide, hydro- gen sulphide, and other gases produced by the action of a liquid upon a solid at ordinary temperatures, are best prepared in one of the forms of apparatus shown in Figs. 16 and 17. The solid material is placed in the larger bottle (Fig. 16), or over a layer of broken glass about five centi- metres thick in the bottle A (Fig. 17). The liquid reagent is from time to time introduced by the funnel tube. Fig. 16: or the bottle B, Fig. 17, is filled with it. The wash-bottles are partially filled with water to arrest any liquid or solid impurity. The apparatus, Fig. 17, has the advantage of being always ready for use; when the stopcock is open the gas escapes, when it is closed the internal pressure depresses the level of the liquid in A into the layer of broken glass, and the action is arrested. Fig. 16. Properties.—Physical.—Hydrogen is a colorless, odorless, tasteless gas; 14.47 times lighter than air, being the lightest substance known. The weight of a litre, 0.0896 gram, is called a crith {Kpidy = barleycorn). HYDROGEN. 41 It is almost insoluble in water and alcohol. In obedience to the law : The difusibility of two gases varies inversely as the square roots of their densities, it is the most rapidly diffusible of gases. The rapidity with which this diffusion takes place renders the use of hydrogen, which has been kept for even a short time in gas-bags or gasometers, dangerous. At 140° (229° F.), under a pressure of 650 atmospheres, it forms a steel-blue liquid. • Certain metals have the power of absorbing large quantities of hydrogen, which is then said to be occluded. Palladium ab- sorbs 376 volumes at the ordinary temperature ; 643 vols. at 90° (194° F.), and 526 vols. at 245° (473° F.). The occluded gas is driven off by the application of heat, and possesses great chemical activity, similar to that which it has when in the nascent state. This latter quality would seem to indicate that the gas is contained in the metal, not in a mere physical state of condensation, but in chemical Fig. 17. Chemical.—Hydrogen exhibits no great tendency to combine with other elements at ordinary temperatures ; the only one with which it combines under such circumstances is chlorine, and then only under the influence of light. It does not support combustion, but, when ignited, burns with a pale blue and very hot flame ; the result of the combination being water. Mixtures of hydrogen and oxygen (in the proportion of 2H to O) explode violently on the approach of flame or by the passage of the electric spark, the explosion being caused by the sudden expansion of the vapor of water formed, under the influence of the heat of the reaction. Hydrogen also unites with oxygen when brought in contact with spongy platinum. Many compounds containing oxygen give up that element when heated in an atmosphere of hydrogen : Cupric oxide. CuO + H, = Cu + HaO. Hydrogen. Copper. Water. The removal of oxygen from a compound is called a reduction or deoxi- dation. At the instant that H is liberated from its compounds it has a deoxi- dizing power similar to that which ordinary H possesses only at elevated temperatures. The greater energy of H, and of other elements as well, in this nascent state, may be thus explained: free H exists in the form of molecules, each one of which is composed of two atoms. At the instant of its liberation from a compound, on the other hand, it is in the form of individual atoms, and that portion of force required to split up the mole- cule into atoms, necessary when free H enters into reaction, is not re- quired when the gas is in the nascent state, and consequently a less addition of force in the shape of heat is required to bring about the reaction. In its physical and chemical properties, this element more closely re- sembles those usually ranked as metals than it does those forming the class of metalloids, among which it is usually placed ; its conducting power, 42 MANUAL OF CHEMISTRY. its appearance in the liquid form, as well as its relation to the acids, which may be considered as salts of H, tend to separate it from the metalloids. Analytical Characters.—(1.) Burns with a faintly blue flame, which deposits water on a cold surface brought in contact with it; (2.) Mixed with oxygen, explodes on contact with flame, producing water. OXYGEN. Symbol = O—Divalent—Atomic weight = 16 ; molecular weight — 32— sp. gr. — 1.10563 A {calculated = 1.1088) ; 15.95 H; sp. gr. of liquids 0.9787—One litre weighs 1.4336 grams — 16 crilhs—100 cubic inches weigh 34.27 grains— Name derived from s = acid, and yewaw = I produce—Dis- covered by Mayow in 1674 ; re-discovered by Priestley in 1774. Occurrence.—Oxygen is the most abundant of the elements. It exists free in atmospheric air ; in combination in a great number of substances, mineral, vegetable, and animal. Preparation.—(1.) By heating certain oxides : 2HgO = 2Hg + 02 Mercuric oxide. Mercury. Oxygen. This was the method used by Priestley : 100 grams of mercuric oxide produce 5.16 litres of oxygen : 3MnO, = Mn304 + Oa Manganese dioxide. Trimanganic tetroxide. Oxygen. The black oxide of manganese is heated to redness in an iron or clay retort (Scheele, 1775) ; and 100 grams yield 8.51 litres of oxygen. (2.) By the electrolysis of water, acidulated with sulphuric acid, O is given off at the positive pole. (3.) By the action of sulphuric acid upon certain compounds rich in O : manganese dioxide, potassium dichromate, and plumbic peroxide : 2MnO, + 2S04H, = 2S04Mn + 2H,0 + O, Manganese dioxide. Sulphuric acid. Manganous sulphate. Water. Oxygen. 100 grams of manganese dioxide produce 12.82 litres of O. (4.) By decomposing S04H2 at a red heat, 2S04H, = 2SO, 4- 2H,0 + 0„. (5.) By the decomposition by heat of certain salts rich in O : alkaline permanganates, nitrates, and chlorates. The best method, and that usually adopted, is by heating a mixture of potassium chlorate and manganese dioxide in equal parts, moderately at first and more strongly toward the end of the reaction. At the end of the operation the manganese dioxide remains, apparently unaltered, and it is probable that during the action it goes through a series of oscillating oxi- dations and deoxidations, which take place at a lower temperature than that required for the decomposition of the chlorate alone. The chlorate gives up all its O (27.26 litres from 100 grains of the salt), according to the equation : 2C10,K = 2KC1 + 30, Potassium chlorate. Potassium chloride. Oxygen. OXYGEN". 43 The operation may be conducted in the apparatus shown in Fig. 18, or, on a large scale, with a copper or iron retort. Properties.—Physical.—Oxygen is a colorless, odorless, tasteless gas, very sparingly soluble in water, somewhat more soluble in absolute alco- hol. It liquefies at — 140° (229° F.) under a pressure of 300 atmospheres. Chemical.—Oxygen is characterized, chemically, by the strong ten- dency which it exhibits to enter into combination with other elements, only one of which is known, i.e., fluorine, that does not form an oxygenated compound. With most elements it unites directly, especially at elevated temperatures. In many instances this union is attended by the appear- ance of light, and always by the extrication of heat. The luminous union of O with another element constitutes the familiar phenomenon of combus- tion, and is the principal source from which we obtain so-called artificial Fig. 18. heat and light. A body is said to be combustible when it is capable of so energetically combining with the oxygen of the air as to liberate light as well as heat. Gases are said to be supporters of combustion, when com- bustible substances will unite with them, or with some of their constitu- ents, the union being attended with the appearance of heat and light. The distinction between combustible substances and supporters of com- bustion is, however, one of mere convenience ; the action taking place be- tween the two substances, one is as much a party to it as the other. A jet of air burns in an atmosphere of coal-gas as readily as a jet of coal-gas burns in air. The process of respiration is very similar to combustion, and as oxygen gas is the best supporter of combustion, so, in the diluted form in which it exists in atmospheric air, it is not only the best, but the only supporter of animal respiration. (See carbon dioxide.) Analytical Characters.—1.) A glowing match-stick bursts into flame in free oxygen. 2.) Free O when mixed with nitrogen dioxide produces a brown gas. 44 MANUAL OF CHEMISTRY. OZONE.—ALLOTROPIC OXYGEN. Air through which discharges of static electricity have been passed, and oxygen obtained by decomposition of water (if electrodes of gold or platinum be used) have a peculiar odor, somewhat resembling that of sul- phur, which is due to the conversion of a part of the oxygen into ozone. Ozone has not been obtained free from oxygen ; indeed, the highest degree of concentration which has been reached does not exceed ten per cent, of ozone. Thus diluted, ozone is produced : 1.) By the decomposi- tion of water by the battery. 2.) By the slow oxidation of phosphorus in damp air. 3.) By the action of concentrated sulphuric acid upon barium dioxide. 4.) By the passage of electric discharges through air or oxygen. It is by the last method that ozonized oxygen is usually obtained artifi- cially, and that the traces of ozone existing in the atmosphere are pro- duced. When oxygen is ozonized it contracts slightly in volume, and when the ozone is removed from ozonized oxygen by mercury or potassium iodide, the volume of the gas is not diminished. These facts, and the great chem- ical activity of ozone, have led chemists to regard it as condensed oxygen ; the molecule of ozone being represented thus (OOO), while that of ordi- nary oxygen is (00). Ozone is very sparingly soluble in water, insoluble in solutions of acids and alkalies. In the presence of moisture it is slowly converted into ox- ygen at 100° (212° F.), a change which takes place rapidly and completely at 237° (459° F.). It is a powerful oxidant; it decomposes solutions of potassium iodide with formation of potassium hydrate and liberation of iodine ; it oxidizes all metals except gold and platinum, in the presence of moisture ; it decolorizes indigo and other organic pigments, and acts rapidly upon rubber, cork, and other organic substances. Analytical Characters.—1.) Neutral litmus paper, impregnated with solution of potassium iodide, is turned blue when exposed to air con- taining ozone. The same litmus paper without iodide is not affected. 2.) Manganous sulphate solution is turned brown by ozone. 3.) Solutions of thallous salts are colored yellow or brown by ozone. When inhaled, air containing 0.07 gram of ozone per litre causes in- tense coryza and haemoptysis. Its presence in atmospheric air has been considered by some as favoring, and by others as preventive of contagious diseases ; certain it is that, by its oxidizing action, ozone is fatal to the lower forms of animal and vegetable life. Compounds of Hydrogen and Oxygen. Two are known—hydrogen oxide or water, H„0 ; hydrogen peroxide or oxygenated water, H.,02. Water. HaO—Molecular weight = 18—Sp. gr. = 1—Vapor density = 0.6234 A — Composition discovered by Priestley in 1780. Occurrence.—In unorganized nature H.,0 exists in the gaseous form in atmospheric air and in volcanic gases ; in the liquid form very abundantly ; and as a solid in snow, ice, and hail. WATER 45 As water of crystallization it exists in definite proportion in certain crystals, to the maintenance of whose shape it is necessary. In the organized world HaO forms a constituent part of every tissue and fluid. Formation.—Water is formed : 1. By union, brought about by eleva- tion of temperature, of one vol. O with two vols. H. 2. By burning H or substances containing it in air or O. 3. By heating organic substances containing H to redness with cupric oxide, or with other substances capable of yielding O. This method of formation is utilized to determine the amount of H contained in organic substances. 4. When an acid and a hydrate react upon each other to form a salt: Sulphuric acid. S04H2 + 2KHO = SO,K2 + 2H20 Potassium hydrate. Potassium sulphate. Water. 5. When a metallic oxide is reduced by hydrogen : CuO + H3 = Cu + H20 6. In the reduction and oxidation of many organic substances. Pure H,0 is not found in nature. When required pure it is separated from suspended matters by filtration, and from dissolved substances by distillation. Cupric oxide. Hydrogen. Copper. Water. Properties.—Physical.—With a barometric pressure of 760 mm. H O is solid below 0° (32° F.) ; liquid between 0° (32° F.) and 100° (212° F.) ; and gaseous above 100° (212° F.). When HaO is enclosed in capillary tubes, or is at complete rest, it may be cooled to—15° (5° F.) without solid- ifying. If at this temperature it be agitated, it solidifies instantly and the temperature suddenly rises to 0° (32° F.). The melting-point of ice i3 lowered 0.0075° (0.0135° F.) for each additional atmosphere of pressure. The boiling-point is subject to greater variations than the freezing- point. It is the lower as the pressure is diminished, and the higher as it is increased. Advantage is taken of the reduced boiling-point of solutions in vacuo for the separation of substances, such as cane sugar, which are injured at the temperature of boiling H20. On the other hand the in- creased temperature that may be imparted to liquid H20 under pressure is utilized in many processes, in the laboratory and in the arts, for effecting solutions and chemical actions which do not take place at lower tempera- tures. The boiling point of H.20 holding solid matter in solution is higher than that of pure H20, the degree of increase depending upon the amount and nature of the substance dissolved. On the other hand, mixtures of H20 with liquids of lower boiling-point boil at temperatures less than 100° (212° F.). Although the conversion of water into water-gas takes place most actively at 100° (212° F.), water and ice evaporate at all temperatures. Water is the best solvent we have, and acts in some instances as a sim- ple solvent, in others as a chemical solvent. Solution is effected in two ways : Simple or physical solution is the dissolving of a solid, liquid, or gas in a liquid without the occurrence of any chemical change. It is a mere physical dissemination of the particles of the dissolved substance among those of the solvent. In this,'true solution, as in all instances where a substance passes from the solid to the liquid form, there is absorption of heat and consequent diminution of temperature. 46 MANUAL OF CHEMISTRY. In chemical solution the dissolved substance is chemically acted upon by the solvent. "When copper dissolves in nitric acid it is not dissolved as copper, but is converted into copper nitrate, which subsequently dissolves. In this case, as in all instances where chemical union occurs, there is lib- eration of heat. It may occur that in chemical solutions there is not elevation but diminution of temperature ; in that event the absorption of heat by the physical act of solution has been greater than the liberation by the chem- ical action ; the sum being a minus quantity. The quantity of a substance which a given volume of H20 is capable of dissolving depends upon the nature of the substance, the temperature, the presence or absence of other substances already in solution, and the presence or absence of another solvent (see p. 34). Some substances are much more soluble in HaO than others ; barium sulphate is insoluble in HaO, while calcium chloride has such an avidity for the solvent that, when exposed to the air, it quickly absorbs sufficient HaO therefrom to form a solution. When a solid absorbs sufficient water from the air to form a solution it is said to deliquesce. Gases are more soluble in cold than in hot liquids. Hydrogen forms an exception to this rule, being equally soluble at all temperatures. The solubility of a gas in water varies directly as the pressure. In most cases solids are more soluble in hot than in cold liquids. When a liquid contains as much of a dissolved substance as it is capable of holding at the existing temperature, it is said to be saturated. Solutions of certain salts, saturated at high temperatures, may be cooled without depositing any of the salt; they are then super-saturated, and contain more of the dissolved substance than they could take up at the lower temperature. A saturated solution of one substance in HaO is often capable of dis- solving considerable quantities of another substance, and of then becom- ing capable of taking up a further quantity of the first substance. The power of H.,0 to dissolve gases increases with increased pressure. Fats, resins, and, in general, organic substances containing a large number of carbon atoms, are insoluble in H20. Vapor of water is colorless, transparent, and invisible. Sp. gr. 0.6234 A or 9 H. A litre of vapor of water weighs 0.8064. The latent heat of vaporization of water is 636.5 ; that is, as much heat is required to vapor- ize 1 kilo, of water at 100° as would suffice to raise 536.6 kilos of water 1° in temperature. In passing from the liquid to the gaseous state, water expands 1,696 times in volume. Chemical.—Water may be shown to consist of 1 vol. O and 2 vols. H ; or 8 by weight of O and 1 by weight of H ; either by analysis or synthesis. Analysis is the reducing of a compound to its constituent elements. Synthesis is the formation of a compound from its elements. A partial synthesis is one in which a complex compound is produced from a simpler one, but not from the elements. Water may be resolved into its constituent gases : 1st. By electrolysis of acidulated water ; H being given off at the negative and O at the posi- tive pole. 2d. By passing vapor of H„0 through a platinum tube heated to a whiteness, or through a porcelain tube, heated to about 1,100°. 3d. By the action of the alkaline metals. Hydrogen is given off, and the me- tallic hydrate remains in solution in an excess of H20. 4th. By passing vapor of HaO over red-hot iron. Oxide of iron remains and H is given off. WATER. 47 Water combines with oxides to form new compounds, some of which are acids and others bases, known as hydrates. A hydrate is a compound formed by the replacement of part of the hydro- gen of water by another element or radical. The hydrates of the electro-negative elements and radicals are acids ; most of those of the electro-positive elements and radicals are basic hydrates. A compound capable of combining with water to form an acid is called an anhydride. Certain substances, in assuming the crystalline form, combine with a definite proportion of water, which is known as water of crystallization, and whose presence, although necessary to the maintenance of certain physical characters, such as color and crystalline form, does not modify their chem- ical reactions. In many instances a portion of the water of crystallization may be driven off at a comparatively low temperature, while a much higher temperature is required to expel the remainder. This latter is known as water of constitution. The symbol Aq (Latin, aqua) is frequently used to designate the water of crystallization, the water of constitution being indicated by H20. Thus S04Mg H20 + 6 Aq represents magnesium sulphate with one molecule of water of constitution and six molecules of water of crystallization. We consider it preferable, however, as the distinction between water of crys- tallization and water of constitution is only one of degree and not of kind, to use the symbol Aq to designate the sum of the two ; thus, S04Mg + 7 Aq. Crystals which lose their water of crystallization on exposure to air are said to effloresce ; those which do not are said to be permanent. Water decomposes the chlorides of the second class of elements (those of carbon only at high temperatures and under pressure); while the chlorides of the elements of the third and fourth classes are either insolu- ble, or soluble without decomposition. Natural Waters.—Water, as it occurs in nature, always contains solid and gaseous matter in solution, and frequently solids in suspension. Natural waters may be classified, according to the nature and quantity of foreign matters which they contain, into potable and unpotable waters. To the first class belong rain-water, snow- and ice-water, spring-water (fresh), river-water, lake-water, and well-water. To the second class belong stagnant waters, sea-water, and the waters of mineral springs. Rain-water is usually the purest of natural waters, so far as dissolved solids are concerned, containing very small quantities of the chlorides, sulphates, and nitrates of sodium and ammonium. Owing to the large surface exposed during condensation, rain-water contains relatively large quantities of dissolved gases—oxygen, nitrogen, and carbon dioxide ; and sometimes hydrogen sulphide and sulphur dioxide. The absence of car- bonates and the presence of nitrates and oxygen render rain-water particu- larly prone to dissolve lead when in contact with that metal. In summer, rain-water is liable to become charged with vegetable organic matter sus- pended in the atmosphere. Ice-water contains very small quantities of dissolved solids or gases, which, during freezing, remain in great part in the unfrozen water. Sus- pended impurities are imprisoned in the ice and liberated when this is melted. Melted snow contains about the same proportion of fixed solid matter as rain-water, but a less proportion of ammoniacal salts and of gases. Spring-water is rain-water which, having percolated through a portion 48 MANUAL OF CHEMISTRY. of the earth’s crust (in which it may also have been subjected to pressure), has become charged with solid and gaseous matter ; varying in kind and quantity according to the nature of the strata through which it has perco- lated, the duration of contact, and the pressure to which it was subject during such contact. Spring-waters from igneous rocks and from the older sedimentary for- mations are fresh and sweet, and any spring-water may be considered such whose temperature is less than 20° (68° F.), and which does not contain more than 0.4 gram of solid matter to the litre (28 grains per gal.) ; pro- vided that a large proportion of the solid matter does not consist of salts having a medicinal action, and that sulphurous gases and sulphides are absent. Artesian wells are artificial springs, produced by boring in a low-lying district, until a pervious layer between two impervious strata is reached ; the outcrop of the system being in an adjacent elevated region. River-water is a mixture of rain-water, spring-water, and the drainage water of the district through which the river flows, to which snow-water, ice-water, or sea-water is sometimes added. The water of a river flowing rapidly through a granitic region is, unless polluted by man, bright, fresh, and highly aerated ; that of a stream flowing sluggishly through rich al- luvial land is unaerated, and rich in dissolved and suspended solids. The amount of dissolved solids in river water increases with the dis- tance from its source. The chief sources of pollution of river-water are by the discharge into them of the sewage of towns and cities, or of the waste products of factories. Lake-water is an accumulation of river- and rain-water. As the waters of lakes are kept in constant agitation both by the wind and by the cur- rent, they become to a great extent purified from organic contamina- tion. Well-water may be very good or very bad. If the well be simply a res- ervoir dug over a spring, and removed from sources of contamination, it has all the characters of fresh spring-water. If, on the other hand, it be simply a hole dug in the earth, the water which it contains is the surface wrater which has percolated through the thin layer of earth corresponding to the depth of the well, and is consequently warm, unaerated and charged with organic impurity. Wells dug near dwellings are very liable to become charged with the worst of contaminations, animal excreta, by their filtration through the soil, either by reason of the fracture of the house-drain or otherwise. Impurities in Potable Waters.—A water to be fit for drinking pur- poses should be cool, limpid, and odorless. It should have an agreeable taste, neither flat, salty, nor sweetish, and it should dissolve soap readily, without formation of any flocculent precipitate. Although it is safe to condemn a water which does not possess the above characters, it is by no means safe to regard all waters which do pos- sess them as beyond suspicion. To determine whether a water is potable it must be more carefully examined as to the following constituents : Total solids.—The amount of solid material dissolved in potable waters varies from 0.05 to 0.4 gram per litre ; and a water containing more than the latter quantity (28 grains per gall.) is to be condemned on that account alone. To determine the quantity of total solids 25 c.c. of the filtered water are evaporated to dryness in a pre- viously weighed platinum dish, over the water-bath. The dish with the contained dry residue is cooled in a desiccator and again weighed. The increase in weight, multiplied by 40, gives the total solids in grams per litre. WATER, 49 Hardness. —The greater part of the solid matter dissolved in natural waters consists of the salts of calcium, accompanied by less quantities of the salts of magnesium. The calcium salt is usually the carbonate or the sulphate ; sometimes the chloride, phosphate, or nitrate. A water containing an excess of calcareous salt is said to be hard, and one not so charged is said to be soft. If the hardness be due to the pres- ence of the carbonate it is temporary, if due to the sulphate it is perma- nent. Calcium carbonate is almost insoluble in pure water, but in the presence of free carbonic acid the more soluble bicarbonate is dissolved, but on the water being boiled, it is decomposed with precipitation of the carbonate if the quantity exceed 0.5 gram per litre. As calcium sulphate is held in solution by virtue of its own, albeit sparing, solubility, it is not deposited when the water is boiled. An accurate determination of the quantity of calcium and magnesium salts in water is rarely required ; it is, however, frequently desirable to de- termine their quantity approximately, the result being the degree of hardness. For this purpose a solution of soap of known strength is required. This is made by dissolving 10 grams of air-dried, white Castile soap, cut into thin shavings, in a litre of dilute alcohol (sp. gr. 0.949). To determine whether this solution contains the proper amount of soap, 10 c.c. of a solution, made by dissolving 1.11 grams of pure, recently fused calcium chloride in a litre of water, are diluted with 00 c.c. of water and the soap solution added until a persistent lather is produced on agitation. If 11 c.c. of soap solution have been used it has the proper strength ; if a greater or less quantity have been added it must be concentrated or diluted in proportion to the excess or deficiency. The soap solution must not be filtered, but, if turbid, must be shaken before using. To determine the hardness, 70 c.c. of the water to be tested are placed in a glass-stoppered bottle of 250 c.c. capacity, and the soap solution gradually added from a burette. After each addition of Boap solu- tion the bottle is shaken, and allowed to lie upon its side five minutes. This is continued until at the end of five minutes a lather remains upon the surface of the liquid in the bottle. At this time the hardness is in- dicated by the number of c.c. of soap solution added, minus one. If more than 16 c.c. of soap solution are added the liquid in the bottle must be diluted with 70 c.c. of distilled water. A good drinking-water should not have a hardness of more than fifteen. Chlorides.—The presence of the chlorides of the alkaline metals, in quantities not sufficient to be detectable by the taste, is of no importance per se ; but in connection with the presence of organic impurity, a deter- mination of the amount of chlorine affords a ready method of indicating the probable source of the organic contamination. As vegetable organic matter brings with it but small quantities of chlorides, while animal contaminations are rich in those compounds, the presence of a large amount of chlorine serves to indicate that organic impurity is of animal origin. Indeed, when time presses, as during an epidemic, it is best to rely upon determinations of chlorine, and condemn all waters containing more than 0.015 gram per litre (one grain per gallon) of that element. For the determination of chlorine two solutions are required : a solution of silver nitrate containing 4.79 grams per litre; a strong solution of potassium chromate. One hundred c.e. of the water are placed in a beaker with enough of the chromate solution to communicate a distinct yellow color. If the reaction be acid it is rendered neutral or faintly alkaline by the addition of sodium carbonate solution. The silver solu- tion is now allowed to flow in from a burette, drop by drop, during constant agitation, until a faint, reddish tinge persists. At this time the burette reading is taken ; each c.c. of silver solution added represents 0.01 of chlorine per litre. Organic Matter.—The most serious of the probable contaminations of drinking-water is that by organic matters containing nitrogen. When these are present in even moderate quantity, and when, at the same time, the proportion of chlorine is greater than usual, the water has been con- taminated by animal excreta and contains, under suitable conditions, the causes of disease, be they germs or poisons. Of the methods suggested for the determination of the amount of or- ganic matter in natural waters there is unfortunately none which is easy 50 MANUAL OF CHEMISTRY. of application and at the same time reliable. That which yieids the best results is Wanklyn’s process : The following solutions are required; a. Made by dissolving 200 grams of potassium hydrate and 8 grams of potassium permanganate in a litre of water. The solution is boiled down to about 125 c.c., cooled, and brought to its original bulk by the addition of boiled distilled water. b. Nessler's reagent. 35 grams of potassium iodide and 13 grams of mercuric chloride are dissolved in 800 c.c. of water by the aid of heat and agitation. A cold, saturated solution of mercuric chloride is then added, drop by drop, until the red pre- cipitate which is formed is no longer redissolved on agitation; 160 grams of potassium hydrate are then dis- solved in the liquid, to which a slight excess of mercuric chloride solution is finally added, and the bulk of the whole made up to a litre with water. The solution is allowed to stand, decanted, and preserved in com- pletely filled, well-stoppered bottles, e. Standard solutions of ammonia. The stronger of these is made by dissolving 3.15 grams of ammonium chloride in a litre of water. The weaker, by mixing one volume of the stronger with 99 volumes of water. The latter contains 0.00001 gram of ammonia in each c.c., and is the one used in the determ.nations, the stronger solution serving only for its convenient preparation, d. A saturated solution of sodium carbonate, e. Distilled water. The middle third of the distillate, 100 c.c. of which must not be perceptibly colored in ten minutes by the addition of 2 c.c. of Nessler’s reagent. The testing of a water is conducted as follows : Half a litre of the water to be tested (before taking the sample, the demijohn or other vessel containing the water must be thoroughly shaken) is introduced, by a funnel, into a tubulated retort capable of holding one litre. If the water be acid, 10 c.c. of the solution of sodium carbonate d are added. Having connected the retort with a Liebig’s condenser, the joint being made tight by a packing of moistened filter-paper, the water is made to boil as soon as possible by applying the flame of a Bunsen burner brought close to the bottom of the naked retort. The first 50 c.c. of distillate are collected in a cylindrical vessel of clear glass, about an inch in diameter. The following 150 c.c. are collected and thrown away, after which the fire is withdrawn. While these are passing over, the first 50 c.c. are Nesslerized (vide infra), and the result, plus one-third as much again, is the amount of free am- monia contained in the half-Hire of water. When 200 c.c. have distilled over, all the free ammonia has been removed, and it now remains to decom- pose the organic material, and determine the amount of ammonia formed. To effect this, 50 c.c. of the permanganate solution a are added through the funnel to the contents of the retort, which is shaken, stop- pered, and again heated. The distillate is now collected in separate portions of 50 c.c. each, in glass cylin- ders, until 3 such portions have been collected. These are then separately Nesslerized as follows: 2 c.c. of the Nessler reagent are added to the sample of 50 c.c. of distillate; if ammonia be present, a yellow or brown color will be produced, dark in proportion to the quantity of ammonia present. Into another cylin- der a given quantity of the standard solution of ammonia c is allowed to flow from a burette; enough water is added to make the bulk up to 50 c.c., and then 2 c.c. of Nessler reagent. This cylinder, and that con- taining the 50 c.c. of Nesslerized distillate, are then placed side by side upon a sheet of white paper and their color examined. If the shade of color in the two cylinders be exactly the same, the 50 c.c. of distillate contain the same amount of ammonia as the quantity of standard solution of ammonia used. If the colors be different in intensity, another comparison-cylinder must be arranged, using more or less of the standard solution, as the first comparison-cylinder was lighter or darker than the distillate. When the proper simi- larity of shades has been attained, the number of cubic centimetres of the standard solution used is deter- mined by the reading on the burette. This process, which, with a little practice, is neither difficult nor tedious, is to be repeated with the first 50 c.c. of distillate and with the three portions of 50 c.c. each, dis- tilled after the addition of the permanganate solution. If, for example, it required 1 c.c. of standard solu- tion in Nesslerizing the first 50 c.c., and for the others 3.5 c.c., 1.5 c.c., and 0.2 c.c., the following is the re- sult and the usual method of recording it: Free ammonia 01 Correction 003 .013 Free ammonia per litre 026 milligr. Albuminoid ammonia 035 .015 .002 .052 Albuminoid ammonia per litre 104 milligr. If a water yield no albuminoid ammonia it is organically pure, even if it contains much free ammonia and chlorides ; if it contains from .02 to .05 milligrams per litre, it is still quite pure ; when the albuminoid ammonia reaches 0.1 milligr. per litre the water is to be looked upon with suspi- cion ; and it is to be condemned when the proportion reaches 0.15. When free ammonia is also present in considerable quantity, a water yielding 0.05 of albuminoid ammonia is to be looked upon with suspicion. Poisonous Metals.—Those most liable to occur in drinking waters are iron, copper, and lead, and of these the last is the most important. The power possessed by a water of dissolving lead varies materially with the nature of the substances which it holds in solution. The pres- ence of nitrates is favorable to the solution of lead, an influence which is, however, much diminished by the simultaneous presence of other salts. A water highly charged with oxygen dissolves lead readily, especially if the metallic surface be so exposed to the action of the water as to be alter- nately acted upon by it and by the air. On the other hand, waters con- taining carbonates or free carbonic acid may be left in contact with lead with comparative impunity, owing to the formation of a protective coating WATER. 51 of tbe insoluble carbonate of lead on the surface of the metal. This does not apply, however, to water charged with a large excess of carbon dioxide under pressure. Of all natural waters that most liable to contamination with lead is rain-water; it contains ammonium nitrate with very small quantities of other salts ; and it is highly aerated, but contains no car- bonates and comparatively small quantities of carbon dioxide. Obviously, therefor, rain-water should neither be collected from a leaden roof, nor stored in leaden tanks, nor drank after having been long in contact with lead pipes. As a rule, the purer the water the more liable it is to dissolve lead when brought in contact with that metal, especially if the contact occur when the water is at a high temperature, or when it lasts for a long period. To determine the power of water for dissolving lead, take two tumblers of the water to be tested ; in one place a piece of lead, whose surface has been scraped bright, and allow them to stand twenty-four hours. At the end of that time remove the lead and pass sulphuretted hydrogen through the water in both tumblers ; if the one which contained the metal become perceptibly darker than the other, the water has a power of dis- solving lead such as to render its contact with surfaces of that metal dan- gerous if prolonged beyond a short time. To test for the presence of poisonous metals, solution of ammonium sulphydrate is added to the water contained in a porcelain capsule. If a dark color be produced, the water is contaminated with a poisonous metal, whose nature is then to be determined by the appropriate tests. For quantitative determinations, solutions containing known quantities of the poisonous metals are used: for iron 4. Kb grams of ferrous sulphate in a litre of water; for copper 3.93 grams of cupric sulphate to the litre ; and for lead 1.615 gram of lead acetate to the litre. One c.c. of each solution contains 0.001 gram of the metal. To use the solutions 100 c.c. of the water to be tested and 100 c.c. of pure water are placed in two porcelain capsules, to each of which some ammonium sulphydrate is then added. The appropriate stand- ard solution is then allowed to flow into the capsule containing the pure water, until the shade of color produced is the same as that of the liquid in the other capsule. The burette reading at this time gives the number of centigrams of the metal in a litre of water. Suspended solids.—Most natural waters deposit, on standing, more or less solid, insoluble material. These substances have been either sus- pended mechanically in the water, which deposits them when it remains at rest, or they have been in solution, and are deposited by becoming in- soluble as the water is deprived of carbon dioxide by exposure to air and by relief from pressure. The suspended particles should be collected by subsidence in a conical glass, and should bo examined microscopically for low forms of animal and vegetable life. The quantity of suspended solids is determined by passing a litre of the turbid water through a dried and weighed filter, which with the collected deposit, is again dried and weighed. The difference between the two weights is the weight of suspended matter in a litre of the water. Purification of water.—The artificial means of rendering a more or less contaminated water fit for use are of five kinds : 1. Distillation ; 2. Subsi- dence ; 3. Filtration ; 4. Precipitation; 5. Boiling. The method of distillation is used in the laboratory when a very pure water is desired, and also at sea upon steamships, and even on sailing ves- sels upon occasion. Distilled water is, however, too pure for continued use, being hard of digestion, and flat to the taste from the absence of gases and of solid matter in solution. When circumstances oblige the use of such water, it should be agitated with air, and should be charged with inorganic matter to the extent of about 0.15 gram each of calcic bicarbon- ate and sodium chloride to the litre. Purification by subsidence is adopted only as an adjunct to precipitation and filtration, and for the separation of the heavier particles of suspended matter. 52 MANUAL OF CHEMISTRY. The ideal process of filtration consists in the separation of all particles of suspended matter, -without any alteration of such substances as are held in solution. In the filtration of potable waters on a large scale, however, the more minute particles of suspended matters are only partially sepa- rated, while, on the other hand, an important change in the dissolved materials takes place, at least in certain kinds of filters, in the oxidation of organic matters, whether in solution or in suspension. In the filtration of large quantities of water it is passed through sand or charcoal, or through both substances arranged in alternate layers. Filtration through charcoal is much more effective than that through sand, owing to the much greater activity of the oxidation of nitrogenized organic matter in the former case. Precipitation processes are only adapted to hard waters, and are de- signed to separate the excess of calcium salt, and at the same time a con- siderable quantity of organic matter, which is mechanically carried down with the precipitate. The method usually followed consists in the addi- tion of lime (in the form of lime-water), in just sufficient quantity to neutralize the excess of carbon dioxide present in the water. The added lime, together with the calcium salt naturally present in the water, is then precipitated, except that small portion of calcium carbonate which the water, freed from carbon dioxide, is capable of dissolving. To determine when sufficient lime-water has been added, take a sample from time to time during the addition, and test it with solution of silver nitrate until a brown precipitate is formed. At this point cease the addition of lime- water and mix the limed water with further portions of the hard water, until a sample, treated with silver-nitrate solution, gives a yellowish in place of a brown color. The purification of water by boiling can only be carried on upon a small scale ; it is, however, of great value for the softening of temporarily hard waters, and for the destruction of organized impurities, for which latter purpose it should never be neglected during outbreaks of cholera and typhoid, if, indeed, water be drank at all at such times. Mineral Waters.—Under this head are classed all waters which are of therapeutic or industrial value, by reason of the quantity or nature of the dissolved solids which they contain ; or which have a temperature greater than 20° (68° Fah.). The composition of mineral waters varies greatly, according to the na- ture of the strata or veins through which the wTater passes, and to the conditions of pressure and previous composition under which it is in con- tact with these deposits. The substances almost universally present in mineral waters are : oxy- gen, nitrogen, carbon dioxide ; sodium carbonate, bicarbonate, sulphate and chloride ; calcium carbonate and bicarbonate. Of substances occasion- ally present the most important are : sulphydric acid ; sulphides of sodium, iron and magnesium ; bromides and iodides of sodium and magnesium ; calcium and magnesium chlorides ; carbonate, bicarbonate, sulphate, per- oxide, and crenate of iron ; silicates of sodium, calcium, magnesium, and iron ; aluminium salts ; salts of lithium, csesium, and rubidium ; free sul- phuric, silicic, arsenic, and boric acids ; and ammoniacal salts. Although a sharply defined classification of mineral waters is not pos- sible, one which is useful, if not accurate, may be made, based upon the predominance of some constituent, or constituents, which impart to the water a well-defined therapeutic value. A classification which has been generally adopted is into five classes : I. Acidulous waters; whose value depends upon dissolved carbonic acid. WATEE 53 They contain but small quantities of solids, principally the bicarbonates of sodium and calcium and sodium chloride. II. Alkaline waters ; which contain notable quantities of the carbonates or bicarbonates of sodium, potassium, lithium, and calcium, sufficient to communicate to them an alkaline reaction, and frequently a soapy taste ; either naturally or after expulsion of carbon dioxide by boiling. III. Chalybeate waters ; which contain salts of iron in greater propor- tion than 40 milligrams per litre (2.8 grains per gall.). They contain fer- rous bicarbonate, sulphate, crenate, and apocrenate, calcium carbonate, sulphates of potassium, sodium, calcium, magnesium, and aluminium, notable quantities of sodium chloride, and frequently small amounts of ar- senic. They have the taste of iron and are usually clear as they emerge from the earth. Those containing ferrous bicarbonate deposit a sediment on standing, by loss of carbon dioxide and formation of ferrous carbonate. IV. Saline waters ; which contain neutral salts in considerable quantity. The nature of the salts which they contain is so diverse that the group may well be subdivided : a Chlorine icaters ; which contain large quantities of sodium chloride, accompanied by less amounts of the chlorides of potassium, calcium, and magnesium. Some are so rich in sodium chloride that they are not of service as therapeutic agents, but are evaporated to yield a more or less pure salt. Any natural water containing more than 3 grams per litre (210 grains per gall.) of sodium chloride belongs to this class, provided it do not contain substances more active in their medicinal action in such pro- portion as to warrant its classification elsewhere. Waters containing more than 15 grams per litre (1,050 grains per gall.) are too concentrated for internal administration. Sulphate waters are actively purgative from the presence of consider- able proportions of the sulphates of sodium, calcium, and magnesium. Some contain large quantities of sodium sulphate, with mere traces of the calcium and magnesium salts, while in others the proportion of the sul- phates of magnesium and calcium is as high as 30 grams per litre (2,100 grains per gall.), to 20 grams per litre (1,400 grains per gall.) of sodium sulphate. They vary much in concentration ; from 5 grams (350 grains per gall.) of total solids to the litre in some, to near 60 grams per litre (4,200 grains per gall.) in others. They have a salty, bitter taste, and vary much in temperature. y. Bromine and iodine waters are such as contain the bromides or iodides of potassium, sodium, or magnesium in sufficient quantity to com- municate to them the medicinal properties of those salts. Y. Sulphurous waters ; which hold hydrogen sulphide or metallic sul- phides in solution. They have a disagreeable odor and are usually warm. They contain 0.2 to 4 grams of solids per litre (14-280 grains per gall.). Physiological. —Water is taken into the body both as a liquid and as a constituent of every article of food ; the amount ingested by a healthy adult being 2.25 to 2.75 litres (2J to 3 quarts) per diem. The greater the elimination and the drier the nature of the food the greater is the amount of H„0 taken in the liquid form. Water is a constituent of every tissue and fluid of the body, varying from 0.2 per cent, in the enamel of the teeth to 99.5 per cent, in the per- spiration and saliva. It constitutes about 60 per cent, of the weight of the body. The consistency of the various parts does not depend entirely upon the relative proportion of solids and HaO, but is influenced by the nature of 54 MANUAL OF CHEMISTRY. the solids. The blood, although liquid in the ordinary sense of the term, contains a less proportional amount of H20 than does the tissue of the kidneys, and about the same proportion as the tissue of the heart. Although the bile and mucus are not as fluid as the blood, they contain a larger proportion of H.,0 to solids than does that liquid. Water is discharged by the kidneys, intestine, skin, and pulmonary surfaces. The quantity discharged is greater than that ingested ; the excess being formed in the body by the oxidation of the H of its organic constituents. Hydrogen Dioxide. Hydrogen peroxide—Oxygenated water. H O,—Molecular weight — 34—Sp. gr. = 1.455—Discovered by Then- ard in 1818. This substance may be obtained in a state of purity by accurately fol- loAving the process of Thenard. It may also be obtained, mixed with a large quantity of H„0, by passing a rapid current of carbon dioxide through H20 holding hydrate of barium dioxide in suspension —Ba03H9 + C02 = C03Ba + H20„. It is also formed in small quantity during the slow oxidation of many elements and compounds, such as P, Pb, Zn, Cd, Al, alcohol, ether, and the essences. The pure substance is a colorless, syrupy liquid, which, when poured into H20, sinks under it before mixing. It has a disagreeable, metallic taste, somewhat resembling that of tartar emetic. When taken into the mouth it produces a tingling sensation, increases the flow of saliva, and bleaches the tissues with which it comes in contact. It is still liquid at —30° (— 22° F.). It is very unstable, and, even in darkness and at ordinary temperatures, is gradually decomposed. At 20° (68° F.) the decomposi- tion takes place more quickly, and at 100° (212° F.) rapidly and with ef- fervescence. The dilute substance, however, is comparatively stable, and may be boiled and even distilled without suffering decomposition. Hydrogen peroxide acts both as a reducing and an oxidizing agent. Arsenic, sulphides, and sulphur dioxide are oxidized by it at the expense of half its oxygen. When it is brought in contact with silver oxide both substances are violently decomposed, water and elementary silver remain- ing. By certain substances, such as gold, platinum, and charcoal in a state of fine division, fibrin, or manganese dioxide, it is decomposed with evolution of oxygen ; the decomposing agent remaining unchanged. The pure substance, when decomposed, yields 475 times its volume of oxygen ; the dilute 15 to 20 volumes. In dilute solution it is used as a bleaching agent and in the renovation of old oil-paintings. Analytical Chakacteks.—1. To a solution of starch a few drops of potassium iodide solution are added, then a small quantity of the fluid to be tested, and, finally, a drop of a solution of ferrous sulphate. A blue color is produced in the presence of hydrogen peroxide, even if the solu- tion contain only 0.05 milligram per litre. 2. Oxygenated water produces' a blue color with a mixture of tincture of guaiacum and extract of malt. FLUOKINE. CLASS II.—ACIDULOUS ELEMENTS. Elements all of whose Hydrates are Acids, and which do not form Salts with the Oxacids. I. CHLORINE GROUP. Fluorine. Chlorine. Bromine. Iodine. The elements of this group are univalent. "With hydrogen they form acid compounds, composed of one volume of the element in the gaseous state with one volume of hydrogen. Their hydrates are monobasic acids when they exist (fluorine forms no hydrate). The first two are gases, the third liquid, the fourth solid at ordinary temperatui'es. They are known as the halogens. The relations of their compounds to each other are shown in the following table : HF, • HC1, C120 C1203 C1204 C10H C102H C10,H C104H HBr — BrOH BrO,H Br04H HI I„04 IOH I02H I03H I04H Hydro-ic acid. Monoxide. Trioxide. Tetroxide. Hypo-ous acid, -ous acid. -ic acid. Per-ic acid. FLUORINE. Symbol = F—Atomic weight — 19—Discovered by Sir II. Davy in 1812. Although many attempts have been made to isolate this element, it has probably never been obtained in the free state, unless the colorless gas obtained by G. J. and Th. Knox, by the decomposition of mercury fluo- ride and of hydrofluoric acid in vessels of fluor-spar was the element. Fluorine forms compounds with all the other elements except oxygen. Hydrogen Fluoride. Hydrofluoric acid = HF—Molecular weight = 20. Hydrofluoric acid is obtained by the action of an excess of sulphuric acid upon fluor-spar, with the aid of gentle heat: CaFl2 + S04H2 = S04Ca + 2HF. If a solution be desired, the operation is conducted in a platinum or lead retort, whose beak is connected with a U-shaped receiver of the same metal, which is cooled and contains a small quantity of water. The aqueous acid is a colorless liquid, highly acid and corrosive, and having a penetrating odor. Great care must be exercised that neither the solution nor the gas come in contact with the skin, as they produce pain- ful ulcers which heal with difficulty, and also constitutional symptoms which may last for days. When the acid has accidentally come in contact with the skin the part should be washed with dilute solution of potash, and the vesicle which forms should be opened. Its boiling-point is between 15° and 30° (59°- 86° F.). It is still liquid at — 40°, and has a sp. gr. of 1.06. 56 MANUAL OF CHEMISTRY. Both the gaseous acid and its solution remove the silica from glass, a property utilized in etching upon that substance, the parts upon which no action is desired being protected by a coating of wax. The presence of fluorine in a compound is detected by reducing the substance to powder, moistening it with sulphuric acid in a platinum cru- cible, over which is placed a slip of glass prepared as above ; at the end of half an hour the wax is removed from the glass, which will be found to be etched if the substance examined contained a fluoride. CHLORINE. Symbol — Cl—Atomic weight — 35.5—Molecular weight = 71—Sp. gr. — 2.4502 A — One litre weighs 3.17 grams—100 cubic inches weigh 76.3 grains—Name derived from yXcnpos = yellowish-green—Discovered by Scheele in 1774. Occurrence.—Only in combination, most abundantly in sodium chlo- ride. Preparation.—(1.) By heating together manganese dioxide and hydro- chloric acid (Scheele). The reaction takes place in two stages : manganic chloride is first formed according to the equation: MnOa + 4HC1 = MnCl4 + 2H20 ; and is subsequently decomposed into manganous chlo- ride and chlorine : MnCl4 = MnCla -j- Cl2. This and Rimilar operations are usually conducted in an apparatus such as that shown in Fig. 19. The earthenware vessel A (which on a small scale may be replaced by a glass flask) is two-thirds filled with lumps of manganese dioxide of the size of hazel-nuts, and adjusted in the water-bath; hydrochloric acid is poured in through the safety-tube and the bath heated. The disengaged gas is caused to bubble through the small quantity of water in B, is then dried by passage over the fragments of calcium chloride in C, and is finally collected by displacement of air in the vessel D. When the vessel A has become half filled with liquid it is best to decant the solution of manganous chlo- ride, wash the remaining oxide with water and begin anew. A kilo, of oxide yields 257.5 litres of Cl. Fig. 19. (2.) By the action of manganese dioxide upon hydrochloric acid in the presence of sulphuric acid, manganous sulphate being also formed: MnOs + CHLORINE. 2HC1 -f S04H2 = SO„Mn + 2H20 + Cl2. The same quantity of chlorine is obtained as in (1), with the use of half the amount of hydrochloric acid. (3.) By heating a mixture of one part each of manganese dioxide and sodium chloride, with three parts of sulphuric acid. Hydrochloric acid and sodium sulphate are first formed : S04H2-f 2NaCl = S04Na2 + 2HC1; and the acid is immediately decomposed by either of the reactions indi- cated in (1) and (2), according as sulphuric acid is or is not present in excess. (4.) By the action of potassium dichromate upon hydrochloric acid ; potassium and chromic chlorides being also formed : Cr201K„ + 14HC1 = 2KC1 + Cr2Cl„ + 7H20 + 3C12. Two parts of powdered dichromate are heated with 17 parts of acid of sp. gr., 1.16 ; 100 grams of the salt yield- ing 22.5 litres of Cl. (5.) When a slow evolution of Cl, extending over a considerable period of time, is desired, as for ordinary disinfection, moistened chloride of lime is exposed to the air, the calcium hypochlorite being decomposed by the atmospheric carbon dioxide. If a more rapid evolution of gas be desired, the chloride of lime is moistened with dilute hydrochloric acid in place of with water. Properties.—Physical.—A greenish yellow gas, at the ordinary tempera- ture and pressure; it has a penetrating odor, and is, even when highly diluted, very irritating to the respiratory passages. Being soluble in H20 to the extent of one volume to three volumes of the solvent, it must be collected by displacement of air, as shown in Fig. 19. A saturated aque- ous solution of Cl is known to chemists as chlorine ivater, and in phar- macy as aqua chlori (U. S.), Liquor chlori (7>r.); it should bleach, but not redden, litmus paper. Under a pressure of 6 atmospheres at 0° (32° F.), or atmospheres at 12° (53°.G F.), Cl becomes an oily, yellow liquid, of sp. gr. 1.33 ; and boiling at — 33.6° (— 28°.5 F.). Chemical.—Chlorine exhibits a great tendency to combine with other elements, with all of which, except F, O, N, and C, it unites directly, fre- quently with evolution of light as well as heat, and sometimes with an ex- plosion. With H it combines slowly, to form hydrochloric acid, under the influence of diffuse daylight, and violently in direct sunlight or in highly actinic artificial lights. A candle burns in Cl with a faint flame and thick smoke, its H combining with the Cl, while carbon becomes free. At a red heat Cl decomposes H20 rapidly, with formation of hydro- chloric acid. The same change takes place slowly under the influence of sunlight, hence chlorine water should be kept in the dark or in bottles of yellow glass. In the presence of H20, chlorine is an active bleaching and disinfect- ing agent. It acts as an indirect oxidant, decomposing H.,0, the nascent O from which then attacks the coloring or odorous principle. Chlorine is readily fixed by many organic substances, either by addi- tion or substitution. In the first instance, as when Cl and olefiant gas unite to form ethylene chloride, the organic substance simply takes up one or more atoms of chlorine : C2H4 + Cl2 = C2H4C19. In the second instance, as when Cl acts upon marsh gas to produce methyl chloride : CH4 -+- Cl,, = CH3C1 + HC1, each substituted atom of Cl displaces an atom of H, which combines with another Cl atom to form hydrochloric acid. Hydrate of chlorine, C15H20, is a yellowish green, crystalline substance, formed when Cl is passed through chlorine water cooled to 0° (32° F.). It is decomposed at 10° (50° F.). Analytical Characters.—See p. 62. 58 MANUAL OF CHEMISTRY. Hydrogen Chloride. Hydrochloric Acid.—Muriatic Acid.—Acidum Ilydrochloricum (U. S. ; Br.)—HC1—Molecular weight = 36.5—Sp. gr., 1.264 A—A litre weighs 1.6352 gram. Occurrence.—In volcanic gases and in the gastric juice of the mam- malia. Preparation.—(1.) By the direct union of its constituent elements. (2.) By the action of sulphuric acid upon a chloride, a sulphate being at the same time formed: SO,H„ + 2NaCl = S04Na2 + 2HC1. This is the reaction by which the HC1 used in the arts is produced, either as a separate industry or as an incidental product in Leblanc’s pro- cess for obtaining sodium carbonate (q. v.). (3.) Hydrochloric acid is also formed in a great number of reactions, as when Cl is substituted in an organic compound. Properties.—Physical.—A colorless gas, acid in reaction and taste, hav- ing a sharp, penetrating odor, and producing great irritation when in- haled. It becomes liquid under a pressure of 40 atmospheres at 4° (39° F.). It is very soluble in H20, one volume of which dissolves 480 volumes of the gas at 0° (32° F.). Chemical.—Hydrocliloric acid is neither combustible nor a supporter of combustion, although certain elements, such as K and Na, burn in it. It forms white clouds on contact with moist air. Solution oe Hydrochloric Acid.—It is in the form of aqueous solution that this acid is usually employed in the arts and in pharmacy. It is, when pure, a colorless liquid (yellow when impure), acid in taste and reaction, whose sp. gr. and boiling-point vary with the degree of concen- tration. When heated, it evolves HC1, if it contain more than 20 per cent, of that gas, and H„0 if it contain less. A solution containing 20 per cent, boils at 1110 (232° F.), is of sp. gr. 1.099, has the composition HC1 4- 8H20, and distils unchanged. Commercial muriatic acid is a yellow liquid ; sp. gr. about 1.16 ; con- tains 79 per cent. HC1; and contains iron, sodium chloride, and arsenical compounds. Acidum hydrochloricum is a colorless liquid, containing small quantities of impurities. It contains 31.9 per cent. HC1 and its sp. gr. is 1.16 (U. S. ; Br.). The dilute acid is the above diluted with water. Sp. gr. 1.049 = 10 per cent. HC1 (U. S.) ; sp. gr. 1.052 = 10.5 per cent. HC1 (Br.). C. P. (chemically pure) acid is usually the same as the strong pharma- ceutical acid and far from pure (see below). Hydrochloric acid is classed, along with nitric and sulphuric acids, as one of the three strong mineral acids. It is decomposed by many elements, with formation of a chloride and liberation of hydrogen: 2HC1 + Zn = ZnCl2 + H„. With oxides and hydrates of elements of the third and fourth classes it enters into double decomposition, forming H„0 and a chloride: CaO + 2HC1 = CaCl2 + H20 or CaH„0„ + 2HC1 = CaCl, + 2H,0. Most of the metallic chlorides are soluble in H20, those of Ag, Pb, and Hg (ous) being exceptions. The chlorides of the non-metals are decomposed on contact with H„0. Oxidizing agents decompose HC1 with liberation of Cl. A mixture of hydrochloric and nitric acids in the proportion of three molecules of the former to one of the latter, is the acidum nitrohydrochloricum (U. S. ; Br.), COMPOUNDS OF CHLOKINE AND OXYGEN. 59 or aqua regia. The latter name alludes to its power of dissolving gold, by combination of the nascent Cl which it liberates with that metal to form the soluble auric chloride. Impurities.—A chemically pure solution of this acid is exceedingly rare. The impurities usually present are : Sulphurous acid—hydrogen sulphide is given off when the acid is poured upon zinc ; Sulphuric acid—a white precipitate is formed with barium chloride ; Chlorine colors the acid yel- low ; Lead gives a black color when the acid is treated with hydrogen sulphide ; Iron—the acid gives a red color with ammonium sulpliocyanate ; Arsenic—the method of testing by hydrogen sulphide is not sufficient. If the acid is to be used for toxicological analysis, a litre, diluted with half as much H20, and to which a small quantity of potassium chlorate has been added, is evaporated over the water-bath to 400 c.c. ; 25 c.c. of sul- phuric acid are then added, and the evaporation continued until the liquid measures about 100 c.c. This is introduced into a Marsh apparatus and must produce no mirror during an hour. Analytical Characters.—See p. 62. Toxicology.—Poisons and corrosives.—A poison is any substance which, after absorption into the blood, produces death or serious bodily harm. A corrosive is a substance capable of producing death by its chemical action upon a tissue with which it comes in direct contact, without absorption by the blood. Under the above definitions the strong mineral acids act as corrosives rather than as poisons. They produce their injurious results by destroy- ing the tissues with which they come in contact, and will cause death as surely by destroying a large surface of skin as when they are taken into the stomach. The antidote to be given when hydrochloric acid, or other strong min- eral acid, has been taken is magnesia, or, if this be not at hand, soap. The administration of oil is waste of time. The stomach-pump should not be used. Compounds of Chlorine and Oxygen. Three compounds of chlorine and oxygen have been isolated, two be- ing anhydrides. They are all very unstable, and prone to sudden and violent decomposition. Chlorine Monoxide—C1„0—87—= hypochlorous anhydride or oxide, is formed as a blood-red liquid by the action, below 20° (68° F.), of dry Cl upon precipitated mercuric oxide : HgO -I- 2C12 = HgCl3 + C120. It de- composes explosively upon the slightest jar and even spontaneously. On contact with H.,0 it forms hypochlorous acid, ClOH, which may also be obtained by passing Cl through H O holding recently precipitated calcium carbonate in suspension, and distilling. This solution is a yellow liquid, having the odor of Cl and endowed with active oxidizing powers. Owing to its instability it is not used in- dustrially, although the hypochlorites of Ca, K, and Na are. Chlorine Trioxide = chlorous anhydride or oxide, 01,0,, —119—is a yel- lowish green gas, formed by the action of dilute nitric acid upon potas- sium chlorate in the presence of arsenic trioxide. At 50° (122° F.) it explodes. It is a strong bleaching agent; is very irritating when inhaled, and readily soluble in HaO, the solution probably containing chlorous acid, C103H. 60 MANUAL OF CHEMISTRY. Chlorine Tetroxide = chlorine peroxide, C1204—135—is a violently ex- plosive body, produced by the action of sulphuric acid upon potassium chlorate. Below — 20° ( — 4° F.), it is an orange-colored liquid ; above that temperature, a yellow gas. There is no corresponding hydrate known ; and if it be brought in contact with an alkaline hydrate, a mix-, ture of chlorate and chlorite is formed. Besides the above, two oxacids of Cl are known, the anhydrides cor- responding to which have not been isolated. Chloric Acid—C103H — 84.5—obtained in aqueous solution as a strongly acid, yellowish, syrupy liquid, by decomposing its barium salt by the proper quantity of sulphuric acid. Perchloric Acid—C104H—100.5—is the most stable of the series. It is obtained by boiling potassium chlorate with hydrofluosilicic acid, de- canting the cold fluid, evaporating until white fumes appear, decanting from time to time, and finally distilling. It is a colorless, oily liquid ; sp. gr. 1.782 ; which explodes on contact with organic substances or charcoal. BROMINE. Symbol = Br—Atomic weight = 80—Molecular weight = 160—Sp. gr. of liquid — 3.1872 at 0° ; of vapor = 5.54 A—Freezing-point = — 24°.5 (—12°.l F.)—Boiling-point = 63° (145°.4 F.)—Name derived from fipw/j.os = a stench.—Discovered by Balard in 1826—Bromum (U. S. ; Br.). Occurrence.—Only in combination, most abundantly with Na and Mg in sea-water and the waters of mineral springs. Preparation.—It is obtained from the mother liquors left by the evap- oration of sea-water and of that of certain mineral springs, and from sea- weed. These are mixed with sulphuric acid and manganese dioxide and heated, when the bromides are decomposed by the Cl produced, and Br distils. Properties.—Physical.—A dark reddish brown liquid, volatile at all temperatures above — 24°.5 (—12°.l F.); giving off brown-red vapors which produce great irritation when inhaled. Soluble in water to the extent of 3.2 parts per 100 at 15° (59° F.); more soluble in alcohol, carbon disulphide, chloroform, and ether. Chemical.—The chemical characters of Br are similar to those of Cl, but less active. With H„0 it forms a crystalline hydrate at 0° (32° F.): Br. 5H„0. Its aqueous solution is decomposed by exposure to light, with formation of hydrobromic acid. It is highly poisonous. Analytical Characters.—See p. 62. Hydrogen Bromide. Hydrobromic acid—Acidum hydrobromicum dil. (U. S.) = HBr—Mole- cular weight — 81—Sp. gr. = 2.71 A—A litre weighs 3.63 grams—Liquefies at - 69° (-92°. 2 F.)—Solidifies at - 73° (-99°.4 F.). Preparation.—This substance cannot be obtained from a bromide as HC1 is obtained from a chloride. It is produced, along with phosphorous acid, by the action of H.,0, upon phosphorus tribromide : PBr3 + 3HaO = P03H3 + 3HBr; or by the action of Br upon paraffine. IODINE. 61 Properties.—A colorless gas ; produces white fumes with moist air; acid in taste and reaction, and readily soluble in H20, with which it forms a hydrate, HBr2II20. Its chemical properties are similar to those of the corresponding Cl compound. Analytical.—See page 62. Oxacids of Bromine. No oxides of bromine are known, although three oxacids exist, either in the free state or as salts : Hypobromous Acid—BrOH—97—is obtained, in aqueous solution, by the action of Br upon mercuric oxide, silver oxide, or silver nitrate. When Br is added to concentrated solution of potassium hydrate, no hypobro- mite is found, but a mixture of bromate and bromide, having no decolor- izing action. With sodium hydrate, however, sodium liypobromite is formed in solution ; and such a solution, freshly prepared, is used in Knop’s process for determining urea (q. v.). Bromic Acid—Br03H—129—has only been obtained in aqueous solu- tion or in combination. It is formed by decomposing barium bromate with an equivalent quantity of sulphuric acid : (Br03)2 Ba + S04H2 = 2Br 03H + S04Ba. In combination it is produced, along with the bromide, by the action of Br on caustic potassa: 3Br2 + 6KHO = Br03K + 5KBr + 3H20. Perbromic Acid—Br04H—145—is obtained as a comparatively stable, oily liquid, by the decomposition of perchloric acid by Br, and concentrat- ing over the water-bath. It is noticeable in this connection that, while HC1 and the chlorides are more stable than the corresponding Br compounds, the oxygen com- pounds of Br are more permanent than those of CL IODINE. Symbol = 1—Atomic weight — 127—Molecular weight = 254—Sp. gr. of solid = 4.948 ; of vapor = 8.716 A—Fuses at 113°.6 (236°. 5 A7.)—Boils at 175° (347° F.)—Name derived from IwSys = violet—Discovered by Cour- tois in 1811—Iodum (U. S. ; Br.). Occurrence.—In combination with Na, K, Ca, and Mg, in sea-water, the waters of mineral springs, marine plants and animals; cod-liver oil contains about 37 parts in 100,000. Preparation.—It is obtained from the ashes of sea-weed, called kelp or varech. These are extracted with H.20, and the solution evaporated to small bulk. The mother liquor, separated from the other salts which crystallize out, contains the iodides, which are decomposed by Cl, aided by heat, and the liberated iodine condensed. Properties.—Physical.—Iron-gray, crystalline scales, having a metallic lustre. Volatile at all temperatures, the vapor having a violet color and a peculiar odor. It is sparingly soluble in II20, which, however, dissolves larger quantities on standing over an excess of iodine, by reason of the formation of hydriodic acid. The presence of certain salts, notably potas- sium iodide, increase the solvent power of H20 for iodine. The Liq. Iodi 62 MANUAL OP CHEMISTRY. Comp. (U. S), (IAq. Iodi, Br.) is solution of potassium iodide containing free iodine. Very soluble in alcohol; Tinct. iodi (U. S. ; Br.) ; in ether chloroform, benzol, and carbon disulphide. With the three last-named solvents it forms violet solutions, with the others brown solutions. Chemical.—In its chemical characters I resembles Cl and Br, but is less active. It decomposes H20 slowly and is a weak bleaching and oxidizing agent. It decomposes hydrogen sulphide with formation of liydriodic acid and liberation of sulphur. It does not combine directly with oxygen, but does with ozone. Potassium hydrate solution dissolves it, with for- mation of potassium iodide and some liypoiodite. Nitric acid oxidizes it to iodic acid. With ammonium hydrate solution it forms the explosive nitrogen iodide. Impurities. — Non-volatile substances remain when the I is volatilized. Water separates as a distinct layer when I is dissolved in carbon disulph- ide. Cyanogen iodide appears in white, acicular crystals among the crys- tals of sublimed I when half an ounce of the substance is heated over the water-bath for twenty minutes, in a porcelain capsule, covered with a flat-bottomed flask filled with cold water. The last named is the most serious impurity as it is actively poisonous. Toxicology.—Taken internally, iodine acts both as a local irritant and as a true poison. It is discharged as an alkaline iodide by the urine and perspiration, and when taken in large quantity it appears in the fseces. The poison should be removed as rapidly as possible by the use of the stomach-pump and of emetics. Farinaceous substances may also be given. Analytical Characters.—See below. Hydrogen Iodide. Ilydriodic acid—HI—Molecular weight — 128—Sp. gr. 4.443 A. Preparation.—By the decomposition of phosphorous triiodide by water: PI3 + 3H..0 = PO H, + 3HI. Or, in solution, by passing hydrogen sulph- ide through water holding iodine in suspension : H ,S + I2 = 2HI + S. Properties.—A colorless gas, forming white fumes on contact with air, and of strong acid reaction. Under the influence of cold and pressure it forms a yellow liquid, which solidifies at —55° ( — 67° F.). Water dissolves it to the extent of 425 volumes for each volume of the solvent at 10° (50° F.). It is partly decomposed into its elements by heat. Mixed with O it is decomposed, even in the dark, with formation of H,,0 and liberation of I. Under the influence of sunlight the gas is slowly decomposed, although its solutions are not so affected, if they be free from air. Chlorine and bro- mine decompose it, with liberation of iodine. With many metals it forms iodides. It yields up its H readily and is used in organic chemistry as a source of that element in the nascent state. Analytical Characters.—Chlorine, Bromine, and Iodine, and their Bi- nary Compounds.—Chlorine.—(1.) Color. (2.) Odor. (3.) Is dissolved by solutions of the alkaline hydrates, to which it com- municates bleaching powers. (4.) With silver nitrate solution it gives a white ppt., soluble in NH4 HO, insoluble in NO,H. Bromine.—(1.) Color of liquid and vapor. OXACIDS OF IODINE. 63 (2.) Chloroform or carbon disulphide, when shaken with solution of Br, assume a yellow or brown color. (3.) Colors starch paste yellow. Iodine.—(1.) Color of vapor. (2.) Dissolves in chloroform and carbon disulphide with a violet color. (3.) Colors starch-paste deep violet-blue, the color disappearing on heating and returning on cooling. Chlorides.—(1.) With NO,Ag a white ppt., insoluble in NO„H, readily soluble in NH4HO. (2.) With (N03).Hg„ a white ppt., which turns black with NH HO. Bromides.—(1.) With N03Ag a yellowish-white ppt., insoluble in N03 H, sparingly soluble in NH HO. (2.) With chlorine water a yellow color and, when shaken with chloro- form, the latter is colored yellow ; or colors starch-paste yellow. Iodides.—(1.) With N03Ag a yellowish-white ppt., insoluble in NOaH, almost insoluble in NHHO. (2.) With fuming NO H a yellow color, and when shaken with chloro- form the latter is colored violet ; or colors starch paste dark blue. (3.) With PdCl2 a dark brown ppt. Oxacids of Iodine. The best known of these are the highest two of the series—iodic and periodic acids. Iodic Acid—IO;!H—176 — is formed as an iodate, whenever I is dis- solved in a solution of an alkaline hydrate : I6 + 6KHO = IOaK + 5KI + 3H„0 ; as the free acid, by the action of strong oxidizing agents, such as nitric acid or chloric acid, upon I; or by passing Cl for some time through H20 holding I in suspension. Iodic acid appears in white crystals, decomposable at 170° (338° F.), and quite soluble in H,0, the solution having an acid reaction, and a bit- ter, astringent taste. It is an energetic oxidizing agent, yielding up its O readily, with sepa- ration of elementary I or of HI. It is used as a test for the presence of morphine (q. u.). Periodic Acid—IO,H—192—is formed by the action of Cl upon an al- kaline solution of sodium iodate. The sodium salt thus obtained is dis- solved in eitric acid, treated with silver nitrate, and the resulting silver periodate decomposed with H.20. From the solution the acid is obtained in colorless crystals, fusible at 130° (266° F.), very soluble in water, and readily decomposable by heat. n. SULPHUR GROUP. Sulphur—Selenium—Tellurium. The elements of this group are bivalent. With hydrogen they form compounds composed of one volnme of the element, in the form of vapor, with two volumes of hydrogen—the combination being attended with a condensation in volume of one-third. Their hydrates are dibasic acids 64 MANUAL OF CIIEMISTKY. They are all solid at ordinary temperatures. The relation of their com- pounds to each other are shown in the following table : H2S H2Se H2Te S02 Se02 TeOa S03 Se03 Te03 S02H2 SOsH„ SeO. H2 Te03H2 so4h2 Se04H, Te04H3 Hydro-ic acid. Dioxide. Trioxide. -ous acid. Hypo-ous acid. -ic acid. SULPHUR. Symbol — S—Atomic weight = 32—Molecular weight = 64—Sp. gr. of vapor - 2.22 A—Fuses at 114° (237.2° F.)—Boils at 447.3° (837° F.). Occurrence.—Free in crystalline powder, large crystals, or amorphous in volcanic regions. In combination in sulphides and sulphates, and in albuminoid substances. Preparation.—By purification of the native sulphur, or decomposition of pyrites, natural sulphides of iron. Crude sulphur is the product of a first distillation. A second distilla- tion in more perfectly constructed apparatus yields refined sulphur. Dur- ing the first part of the distillation, while the air of the condensing cham- ber is still cool, the vapor of S is suddenly condensed into a fine, crystal- line powder, which is flowers of sulphur, sulphur sublimatum (U. S.). Later, when the temperature of the condensing chamber is above 114°, the liquid S collects at the bottom, whence it is drawn off and cast into sticks of roll sulphur. Properties.—Physical.—Sulphur is usually yellow in color ; at low tem- peratures, and in minute subdivision, as in the precipitated milk of sulphur, sulphur prcecipitatum (U. S.), it is almost or quite colorless. Its taste and odor are faint but characteristic. At 114° (237°.2 F.) it fuses to a thin yel- low liquid, which at 150°-160° (302°-320° F.) becomes thick and brown ; at 330°-340° (626°-642°.2 F.) it again becomes thin and light in color; finally it boils, giving off brownish-yellow vapor at a temperature variously stated between 440° (824° F) and 448° (838°.4 F.). If heated to about 400° (752° F.) and suddenly cooled it is converted into plastic sulphur, w'hich may be moulded into any desired form. It is insoluble in water, sparingly soluble in anilin, phenol, benzol, benzine, and chloroform ; read- ily soluble in protochloride of sulphur and carbon disulphide. It is di- morphous ; when fused sulphur crystallizes it does so in oblique rhombic prisms; its solution in carbon disulphide deposits it on evaporation in rhombic octahedra. The prismatic variety is of sp. gr. 1.95 and fuses at 120° (248° F.) ; the sp. gr. of the octahedral is 2.05, and its fusing point 114°. 5 (238° F.). The prismatic crystals by exposure to air become opaque, by reason of a gradual conversion into octahedra. Chemical.—Sulphur unites readily with other elements, especially at high temperatures. Heated in air or O, it burns with a blue flame to sul- phur dioxide, S02. In H it burns with formation of hydrogen sulphide, H,S. The compounds of S are similar in constitution, and to some extent in chemical properties, to those of O. In many organic substances S may replace O, as in sulphocyanic acid, CNSH, corresponding to cyanic acid, CNOH. Uses.—Sulphur is used principally in the manufacture of gunpowder ; also to some extent in making sulphuric acid, sulphur dioxide, and matches, and for the prevention of fungoid and parasitic growths. HYDROGEN SULPHIDE. 65 Hydrogen Sulphide. Sulphydric acid—Hydrosulphuric acid—Sulphuretted hydrogen. H3S—Molecular weight — 34—Sp. gr. = 1.19 A. Occurrence.—In volcanic gases ; as a product of the decomposition of organic substances containing S ; in solution in the waters of some min- eral springs ; and occasionally in small quantity in the gases of the intes- tine. Preparation.—(1. ) By direct union of the elements ; either by burning S in H, or by passing H through molten S. (2.) By the action of nascent H upon sulphuric acid if the mixture be- come heated. (See Marsh test for arsenic.) (3.) By the action of HC1 upon antimony trisulphide: Sb2S3 + 6HC1 = 2SbCl3 + 3HS. (4.) By the action of dilute sulphuric acid upon ferrous sulphide : FaS + S04H, = S04F2 + H.B. (5.) By the action of HC1 upon calcium sulphide : CaS + 2HC1 = CaCl3 f H„S. The gas is usually obtained in the laboratory by reaction (4), either in an apparatus such as that shown in Fig. 17 (p. 41) or in one of the forms of apparatus shown in Figs. 20, 21. The sulphide is put into the bulb b, Fig. 20, through the opening e, or into the bottle b, Fig. 21. The dilute acid with which the upper- Fig. 20. Fig. 21. most and lowest bulbs, Fig. 20, are filled comes in contact with the sulphide when the stopcock is opened, or in the apparatus. Fig. 21, is poured through the funnel tube c. a is a wash-bottle partly filled with water. As ferrous sulphide is liable to contain arsenic, and as hydrogen sulphide generated from it may be con- taminated with hydrogen arsenide, the gas, when required for toxicological analysis should always be ob- tained by reaction (5) in the apparatus, Fig. 20. Properties.—Physical.—A colorless gas, having the odor of rotten eggs and a disgusting taste ; soluble in H20 to the extent of 3.23 parts to 1 at 15° (59° F.); soluble in alcohol. Under 17 atmospheres pressure, or at — 74° ( — 101°.2 F.) at the ordinary pressure, it liquefies; at — 85.5° ( — 122° F.) it forms white crystals. MANUAL OF CHEMISTRY. Chemical.—Burns in air with formation of sulphur dioxide and water : 2H2S + 302 = 2S02 + 2H20. If the supply of oxygen be deficient, H20 is formed and sulphur liberated : 2H„S 02=2H20 + S2. Mixtures of H2S and air or O explode on contact with flame. Solutions of the gas when ex- posed to air become oxidized with deposition of S. Such solutions should be made with boiled H20 and kept in bottles which are completely filled and well corked. Oxidizing agents, Cl, Br, and I remove its H with depo- sition of S. Hydrogen sulphide and sulphur dioxide mutually decompose each other into water, pentathionic acid and sulphur: 4S02 + 3H2S = 2H20 + S5OfH2 + Ss. When the gas is passed through a solution of an alkaline hydrate its S displaces the O of the hydrate to form a sulphydrate : H2S + KHO = h2o + KHS. With solutions of metallic salts H2S usually relinquishes its S to the metal: S04Cu + H„S = CuS + S04H2, a property which renders it of great value in analytical chemistry. Analytical Characters — Hydrogen sulphide.—(1.) Blackens paper moistened with lead acetate solution. (2.) Has an odor of rotten eggs. Sulphides.—(1.) Heated in the oxidizing flame of the blowpipe, give a blue flame and odor of S02. (2.) With a mineral acid give off HsS (except sulphides of Hg, Au, and Pt). Physiological.—Hydrogen sulphide is produced in the intestine by the decomposition of albuminous substances or of taurochloric acid; it also Fig. 22. occurs sometimes in abscesses, and in the urine in tuberculosis, variola, and cancer of the bladder. It may also reach the bladder by diffusion from the rectum. Toxicology.—An animal dies almost immediately in an atmosphere of pure H.S, and the diluted gas is still rapidly fatal. An atmosphere con- taining one per cent, may be fatal to man, although individuals habituated to its presence can exist in an atmosphere containing three per cent. Even when highly diluted it produces a condition of low fever, and care is to be taken that the air of laboratories in which it is used shall not become con- taminated with it. Its toxic powers are due primarily, if not entirely, to its power of reducing and combining with the blood-coloring matter. The form in which hydrogen sulphide generally produces deleterious effects is as a constituent of the gases emanating from sewers, privies, burial vaults, etc. These give rise to either slow poisoning, as when sewer gases are admitted to sleeping and other apartments by defective plumbing, or to sudden poisoning, as when a person enters a vault or other locality containing the noxious atmosphere. The treatment should consist in promoting the inhalation of pure air, artificial respiration, cold affusions, and the administration of stimulants. After death the blood is found to be dark in color, and gives the spec- trum shown in Fig. 22, due to sulphasmoglobin. SULPHUR DIOXIDE. 67 Sulphur Dioxide. Sulphurous oxide, anhydride or acid—Acidum sulphurosum (U. S. ; Br.)—S02—Molecular weight = 64—Sp. gr. of gas = 2.234; of liquid — 1.45—Liquefies at — 10° (14° F.) ; solidifies at — 75° ( — 103° F.). Occurrence.—In volcanic gases and in solution in some mineral waters. Preparation.—(1.) By burning S in air or O. (2.) By roasting iron pyrites in a current of air. (3.) During the combustion of coal or coal-gas containing S or its compounds. (4.) By heating sulphuric acid with copper : 2S04H2 4- Cu= S04Cu + 2H20 + S02. (5.) By heating sulphuric acid with charcoal: 2S04H2 + C = 2SOa 4- C02 + 2HaO. When the gas is to be used as a disinfectant it is usually obtained by reaction (1) ; in sulphuric acid factories (2) is used; (3) indicates the method in which atmospheric S02 is chiefly produced ; in the labora- tory (4) is used ; (5) is the process directed by the U. S. and Br. Phar- macopeeias. Properties.—Physical.—A colorless, suffocating gas, having a disagree- able and persistent taste. Very soluble in H20, which at 15° (59 J F.) dissolves about 40 times its volume (see below) ; also soluble in alcohol. At — 10° (14° F.) it forms a colorless, mobile, transparent liquid, by whose rapid evaporation a cold of — 65° ( — 85° F.) is obtained. Chemical.—Sulphur dioxide is neither combustible nor a supporter of combustion. Heated with H it is decomposed : S02 + 2H2 = S 4- 2H20. With nascent hydrogen H2S is formed : S02 4- 3H2 = H„S + 2H..O. Water not only dissolves the gas but combines with it to form the true sulphurous acid, SO,H2. With solutions of metallic hydrates it forms metallic sulphites: S02 + KHO = S03KH or S02 + 2KHO — SOsK2 + H20. A hydrate having the composition SO„H2, 8HaO has been obtained as a crystalline solid, fusible at + 4° (39°. 2 F.). Sulphur dioxide and sulphurous acid solution are powerful reducing agents, being themselves oxidized to sulphuric acid : S02 4- H„0 4- O = SO,H2 or SO.,H2 4- O = S04H2. It reduces nitric acid with formation of sulphuric acid and nitrogen tetroxide : S02 4- 2N03H = S04H2 + 2N02. It decolorizes organic pigments, without, however, destroying the pig- ment, whose color may be restored by an alkali or a stronger acid. It destroys HaS, acting in this instance, not as a reducing, but as an oxidiz- ing agent: 4S02 4- 3H2S = 2H20 4- S506H2 4- S2. With Cl it combines directly under the influence of sunlight to form sulphuryl chloride (S02) " Cl2. Sulphurous acid is dibasic. Analytical Characters.—(1.) Odor of burning sulphur. (2.) Paper moistened with starch-paste and iodic acid solution turns blue in air containing 1 in 3,000 of SO„. Sulphites.—(1.) With HC1 give off S02. (2.) With Zn and HC1 give off H2S. (3.) With NO,Ag a white ppt., soluble in excess of sulphite. When the mixture is boiled elementary Ag is deposited. (4.) With (NOa)2Ba a white ppt., soluble in HC1. Solution of Cl added to this solution forms a white ppt., insoluble in acids. 68 MANUAL OF CHEMISTRY. Sulphur Trioxide. Sulphuric oxide or anhydride—SOa—Molecular weight — 80—Sp. gr. 1.95—Fuses at 18.3° (65° F.)—Boils at 35° (95° F.). Preparation.—(1.) By union of SO, and O at 250°-300° (482°-572° F.) or in presence of spongy platinum. (2.) By heating sulphuric acid in presence of phosphoric anhydride : S04H2 + P206 - S03 + 2P03H. (3.) By heating dry sodium pyrosulphate : S207Na2 = S04Na2 + S03. (4.) By heating pyrosulphuric acid below 100° (212° F.) in a retort fitted with a receiver, cooled by ice and salt: S20,H2 = S04H2 + S03. Properties.—White, silky, odorless crystals which give off white fumes in damp air. It unites with H20 with a hissing sound and elevation of temperature to form sulphuric acid. When dry it does not redden litmus. Oxacids of Sulphur. S02H2 Hydrosulphurous acid. SOsH2 Sulphurous acid. S04H2 Sulphuric acid. S2O.H2 Pyrosulphuric acid. S2OfH2 Dithionic acid. S306H2 Trithionic acid. S4OfcH2 Tetrathionic acid. S606H2 Pentathionic acid. SjOjH, Hyposulphurous acid. Hydrosulphurous Acid—S02H2—66. Is an unstable body only known in solution, obtained by the action of zinc upon solution of sulphurous acid. It is a powerful bleaching and deoxidizing agent. Sulphuric Acid. Preparation.—(1.) By the union of sulphur trioxide and water : SO + h2o = so4h2. (2.) By the oxidation of S02 or of S in the presence of water : 2SO + 2H20 + 02 = 2S04H2; or S2 + 2H20 + 302 = 2S04H2. The manufacture of S04H2 may be said to be the basis of all chemical industry, as there are but few processes in chemical technology into some part of which it does not enter. The method followed at present, the re- sult of gradual improvement, may be divided into two stages: 1st, the formation of a dilute acid ; 2d, the concentration of this product. The first part is carried on in immense chambers of timber, lined with lead, and furnishes an acid having a sp. gr. of 1.55, and containing 65 per cent, of true sulphuric acid, SO,H2. Into these chambers S02, obtained by burning sulphur or by roasting pyrites, is driven along with a large excess of air. In the chambers it comes in contact with nitric acid, at the ex- pense of which it is oxidized to S04H„, while nitrogen tetroxide (red fumes) is formed : S02 4- 2NO,H = S04H2 + 2N02. Were this the only reaction the disposal of the red fumes would present a serious difficulty Oil of Vitriol—Acidum sulphuricum (U. 8.; Br.)—S04H2—98. SULPHURIC ACID. 69 and the amount of nitric acid consumed would be very great. A second reaction occurs between the red fumes and H20, which is injected in the form of steam, by which nitric acid and nitrogen dioxide are produced : 3N02 + H20 = 2N03H + NO. The nitrogen dioxide in turn combines with O to produce the tetroxide, which then regenerates a further quan- tity of nitric acid, and so on. This series of reactions is made to go on continuously, the nitric acid being constantly regenerated, and acting merely as a carrier of O from the air to the S02, in such manner that the sum of the reactions may be represented by the equation: 2SO 4 2H O + O, = 2S04H2. The acid is allowed to collect in the chambers until it has the sp. gr. 1.55, when it is drawn off. This chamber acid, although used in a few in- dustrial processes, is not yet strong enough for most purposes. It is con- centrated, first by evaporation in shallow leaden pans until its sp. gr. reaches 1.746 ; at this point it begins to act upon the lead, and is transferred to platinum stills, where the concentration is completed. Varieties.—Sulphuric acid is met with in several conditions of concen- tration and purity : (1.) The commercial oil of vitriol, largely used in manufacturing pro- cesses, is a more or less deeply colored, oily liquid, varying in sp. gr. from 1.833 to 1.842, and in concentration from 93 per cent, to 99£ per cent, of true S04H2. (2.) C. P. acid = Acidum sulphuricum, U. S. ; Br., of sp. gr. 1.84, color- less and comparatively pure (see below). (3.) Glacial sulphuric acid is a hydrate of the composition S04Hr,,H.,0, sometimes called bihydrated sulphuric acid, which crystallizes in rhombic prisms, fusible at -+- 8.°5 (47. °3 F.) when an acid of sp. gr. 1.788 is cooled to that temperature. (4.) Ac. sulph. dil. (U. S. ; Br.) is a dilute acid of sp. gr. 1.069 and containing between 9 and 10 per cent. S04H2 (U. S.), or of sp. gr. 1.094, containing between 12 and 13 per cent. S04H2 (Br.). Properties.—Physical.—A colorless, heavy, oily liquid ; sp. gr. 1.842 at 12° (53.6° F.); crystallizes at 10.°5 (50.°9 F.) ; boils at 338° (640.°4 F.). It is odorless, intensely acid in taste and reaction, and highly corrosive. It is non-volatile at ordinary temperatures. Mixtures of the acid with H„0 have a lower boiling-point and lower sp. gr. as the proportion of H20 in- creases. Chemical.—At a red heat vapor of S04H2 is partly dissociated into S03 and H ,0 ; or, in the presence of platinum, into S02,H20 and O. When heated with S, C, P, Hg, Cu, or Ag, it is reduced, with formation of S02. Sulphuric acid has a great tendency to absorb H20, the union being attended with elevation of temperature, increase of bulk and diminution of sp. gr. of the acid, and contraction of volume of the mixture. Three parts, by weight, of acid of sp. gr. 1.842, when mixed with one part of H„0 produce an elevation of temperature to 130° (266° F.), and the re- sulting mixture occupies a volume i less than the sum of the volumes of the constituents. Strong S04H2 is a good desiccator of air or gases. It should not be left exposed in uncovered vessels lest, by increase of volume, it overflow. When it is to be diluted with H„0, the acid should be added to the H,0 in a vessel of thin glass, to avoid the projection of particles or the rupture of the vessel. It is by virtue of its affinity for H20 that S04H2 chars or dehydrates organic substances. Sulphuric acid is a powerful di- basic acid. Impurities.—The commercial acid is so impure that it is only fit for 70 MANUAL OF CHEMISTRY. manufacturing and the coarsest chemical uses. The so-called C. P. acid may further contain : Lead; becomes cloudy when mixed with 10 times its volume of H20 ; if the quantity of Pb be sufficient, the dilute acid gives a black color with H2S. Salts; leave a fixed residue when the acid is evaporated. Sulphur dioxide ; gives off H2S when the acid, diluted with an equal volume of H20, comes in contact with Zn. Carbon ; communi- cates a brown color to the acid. Arsenic; is very frequently present. When the acid is to be used for toxicological analysis, the test by H2S is not sufficient; the acid, diluted with an equal volume of H20, is to be in- troduced into a Marsh apparatus, in which no visible stain should be pro- duced during an hour. Oxides of nitrogen ; are almost invariably present; they communicate a pink or red color to pure brucine. Analytical Characters.—(1.) Barium chloride (or nitrate) ; a white ppt., insoluble in acids. The ppt., dried and heated with charcoal, forms BaS, which, with HC1, gives off H2S. (2.) Plumbic acetate forms a white ppt., insoluble in dilute acids. (3.) Calcium chloride forms a white ppt., insoluble in dilute HC1 or N03H. Toxicology.—Sulphuric acid is an active corrosive and may be, if taken in sufficient quantity in a highly diluted state, a true poison. The concentrated acid causes death, either within a few hours by corrosion and perforation of the walls of the stomach and oesophagus, or, after many weeks, by starvation due to destruction of the gastric mucous membrane and closure of the pyloric orifice of the stomach. The treatment to be followed is the same as that for corrosion by HC1. (See p. 59.) Pyrosulphuric Acid. Fuming sulphuric acid—Nordhausen oil of vitriol — Disulphuric hy- drate—S207H2—Molecular weight = 178—Sp. gr. = 1.9—Boils at 52. °2 (126° F.). Preparation.—By distilling dry ferrous sulphate ; and purification of the product by repeated crystallizations and fusions, until a substance fusing at 35° (95° F.) is obtained. Properties.—The commercial Nordhausen acid, which is a mixture of S,,07H. with excess of S03, or of S04H„, is a brown, oily liquid, which boils below 100° (212° F.) giving off S03 ; and is solid or liquid according to the temperature. SELENIUM. Symbol = Se—Atomic weight = 79.5—Molecular weight = 159—Sp. gr. of solid = 4.788 ; of vapor = 5.68A—Name from artXfjwi = moon—Dis- covered by Berzelius in 1817. A rare element, occurring in combination with Cu, Fe, Ag and Hg and accompanying S. It is capable of existing in three allotropic forms. Its compounds are similar in constitution to those of S. 71 NITROGEN. TELLURIUM. Symbol = Te—Atomic weight — 128—Molecular weight = 256—Sp. gr. of solid = 6.25; of vapor = 9.0A—Name from tellus = earth—Discovered in 1782 by Muller. One of the least common of the elements, it occurs free and com- bined with Bi, Pb, Ag, Sb, Ni and Au. It is solid, has a metallic lustre, fuses at about 500° (932° F.). Its compounds are similar to those of Se and S. m. NITROGEN GROUP. Nitrogen—Phosphorus—Arsenic—Antimony. The elements of this group are either trivalent or pentavalent. With hydrogen they form non-acid compounds composed of one volume of the element in the gaseous state with three volumes of hydrogen, the union being attended with a condensation of volume of one-half. Their hy- drates are acids containing one, two, three, or four atoms of replaceable hydrogen. Bismuth, frequently classed in this group, is excluded, owing to the existence of the nitrate (N03)3 Bi. The relations existing between the compounds of the elements of this group are shown in the following table : nh3, n„o,no,n2o3, no2,n2o5, — — - N03H PH„ J PA> - PA, P02H3, PO.,H„ P04H3, P20,H4, po3h AsH3, — — As203, — As306, — As03H3, As04H3, As207H4, As03H SbH3, - - Sb303, — Sb20„ — — Sb04H3, Sb„07H4, Sb03H Hyd- Mon- Bi- Tri- Tetr- Tent- Hypo-ous -oua Ortho-ic Pyro-ic Meta-ic ride. oxide. oxide, oxide. oxide. oxide. acid. acid. acid. acid. acid. NITROGEN. Azote—Symbol — N—Atomic weight = 14—Molecular weight = 28—Sp. gr. — 0.9713—One litre weighs 1.263 grams—Name from virpov = nitre, yeveo-i? — source ; or from a, privative far] = life—Discovered by Mayow in 1669. Occurrence.—Free in atmospheric air and in volcanic gases. In com- bination in the nitrates, in ammoniacal compounds and in a great num- ber of animal and vegetable substances. Preparation.—(1.) By removal of O from atmospheric air, or by burn- ing P in air, or by passing air slowly over red-hot copper. It is contam- inated with C03, H20, etc. (2.) By passing Cl through excess of ammonium hydrate solution. If ammonia be not maintained in excess, the Cl reacts with the ammonium chloride formed, to produce the explosive nitrogen chloride. (3.) By heating ammonium nitrite : or a mixture of ammonium chlo- ride and potassium nitrite. Properties.—A colorless, odorless, tasteless, non-combustible gas; not a supporter of combustion ; very sparingly soluble in water. It is very slow to enter into combination, and most of its compounds 72 MANUAL OF CHEMISTRY. are very prone to decomposition, which may occur explosively or slowly. Nitrogen combines directly with O under the influence of electric dis- charges ; and with H under like conditions and indirectly during the decomposition of nitrogenized organic substances. Nitrogen is not poisonous, but is incapable of supporting respiration. Atmospheric Air. The alchemists considered air as an element until Mayow in 1669 demonstrated its complex nature. It was not, however, until 1770 that Priestley repeated the work of Mayow ; and that the compound nature of air and the characters of its constituents were made generally known by the labors (1770-1781) of Priestley, Rutherford, Lavoisier and Cavendish. The older chemists used the terms gas and air as synonymous. Composition.—Air is not a chemical compound, but a mechanical mix- ture of O and N with smaller quantities of other gases. Leaving out of consideration about 0.4 to 0.5 per cent, of other gases, air consists of 20.93 O and 79.07 N, by volume ; or 23 O and 77 N, by weight; pro- portons which vary but very slightly at different times and places; the extremes of the proportion of O found having been 20.908 and 20.999. That air is not a compound is shown by the fact that the proportion of its constituents does not represent a relation between their atomic weights or between any multiples thereof; as well as by the solubility of air in water. Were it a compound it would have a definite degree of solubility of its own, and the dissolved gas would have the same composition as when free. But each of its constituents dissolves in H20 according to its own solubility and air dissolved in H„0 at 13° (55°.4 F.) consists of N and O, not in the proportion given above, but in the proportion 65.27 to 34.72. Besides these two main constituents, air contains about 4-5 thous- andths of its bulk of other substances : vapor of water, carbon dioxide, ammoniacal compounds, hydrocarbons, ozone, oxides of nitrogen, and solid particles held in suspension. Vapor of water.—Atmospheric moisture is either visible, as in fogs and clouds, when it is in the form of a finely divided liquid ; or invisible, as vapor of water. The amount of HaO which a given volume of air can hold without precipitation varies according to the temperature. It hap- pens rarely that air is as highly charged with moisture as it is capa- ble of being for the existing temperature. The difference between the amount of water which the air is capable of holding at the existing tem- perature and that which it actually does hold is its fraction of satu- ration, or hygrometric state. Ordinarily air contains from 66 to 70 per cent, of its possible amount of moisture ; if the quantity be less than this the air is too dry and causes a parched sensation and the sense of “ stuffiness ” so common in furnace-heated houses ; if it be greater, evapor- ation from the skin is impeded and the air is oppressive if warm. The actual amount of moisture in air is determined by passing a known volume through tubes filled with calcium chloride ; whose increase in weight represents the amount of H.,0 in the volume of air used. The frac- tion of saturation is determined by instruments called hygrometers, hygro- scopes or psychrometers. Carbon dioxide.—The quantity of carbon dioxide in free air varies from 3 to 6 parts in 10,000 by volume. (See Carbon dioxide.) Ammoniacal compounds. —Carbonate, nitrate, and nitrite of ammonium AMMONIA. 73 occur in small quantity (0.1 to 6.0 parts per million of NH3) in air, as products of the decomposition of nitrogenized organic substances. They are absorbed and assimilated by plants. Nitric and nitrous acids, usually in combination with ammonium, are produced either by the oxidation of combustible substances containing N, or by direct union of N and HaO during discharges of atmospheric electricity. Rain-water falling during thunder-showers has been found to contain as much as 3.71 per million of NOaH. Sulphuric and sulphurous acids occur in combination with NH4 in the air over cities and manufacturing districts, where they are produced by the oxidation of S existing in coal and coal-gas. Hydrocarbons have been de- tected in the air of cities and of swampy places, in small quantities. Solid particles of the most di- verse nature are always present in air and become visible in a beam of sunlight. Chloride of sodium is almost always present, always in the neighborhood of salt water. Air contains myriads of germs of vegetable organisms, mould, etc., which are propagated by the trans- portation of these germs by air- currents. Whether or no certain diseases are thus propagated by germs or poisons ; and whether low forms of organized beings can or cannot make their appearance without the introduction of germs are questions, both sides of which are supported by active partisans, and concerning which little or nothing is known with certainty. The continued inhalation of air containing large quantities of solid par- ticles in suspension may cause severe pulmonary disorder by mere mechani- cal irritation, and apart from any poisonous quality in the substance ; such is the case with the air of carpeted ball-rooms, and of the workshops of certain trades, furniture-polishers, metal-filers, etc. Fig. 23. Atmospheric dust is best collected by an instrument such as is shown in Fig. 23. A disk of thin glass is fastened upon the plate b, over the small opening in A, and its lower surface moistened with a mixture of equal parts of water and glycerin, the opening C is connected with an aspirator. After one or more cubic metres of air have been drawn through the apparatus, the thin glass is detached and the deposit examined microscopically. Ammonia. Hydrogen nitride—Volatile alkali—NH,—Molecular weight — 17—Sp. grr.= 0.589^4—Liquefies at —40° (— ±0° F*.)—Boils at — 33°.7 (— 28°.7 F.)—Solidifies at — 75° ( —103° F.)—A litre weighs 0.7655 grams. Preparations.—(1.) By union of nascent H with N. (2.) By decomposition of organic matter containing N, either spon- taneously or by destructive distillation. 74 MANUAL OF CHEMISTRY. (3.) By heating a mixture of dry slacked lime with ammonium chloride: 2NH4C1 + CaH202 = CaCl2 + 2H20 + 2NH3. (4.) By heating solution of ammonium hydrate : NH4HO = NH3 + H20. Properties.—Physical.—A colorless gas, having a pungent odor and an acrid taste. It is very soluble in H20, 1 volume of which at 0° (32° F.) dissolves 1050 vols. NH3 and at 15J (59° F.), 727 vols. NH3. Alcohol and ether also dissolve it readily. Liquid ammonia is a colorless, mobile fluid, used in ice machines for producing artificial cold, the liquid absorb- ing a great amount of heat in volatilizing. Chemical.—At a red heat ammonia is decomposed into a mixture of N and H, occupying double the volume of the original gas. It is similarly decomposed by the prolonged passage through it of discharges of elec- tricity. It is not readily combustible, yet it burns in an atmosphere of O with a yellowish flame. Mixtures of NH3 with O, nitrogen monoxide, or nitrogen dioxide, explode on contact with flame. Water dissolves am- monia with elevation of temperature and probably with formation of ammonium hydrate, NH4HO (q. v.). It combines directly with acids to produce ammonium salts, without separation of hydrogen. (See Ammo- nium.) Nitrogen Monoxide Nitrous oxide—Laughing gas—Nitrogen protoxide—N20—Molecular weight — 44—Sp. gr. = 1.5274—Fuses at —100° (—148° F.)—Boils at —87° ( — 124° F.)—Discovered in 1776 by Priestley. Preparation.—By heating ammonium nitrate: N03(NH4) = N.,0 4- 2 H20. To obtain a pure product there should be no ammonium chloride present (as an impurity of the nitrate), and the heat should be applied gradually and not allowed to exceed 250° (482° F.), and the gas formed should be passed through wash-bottles containing sodium hydrate and ferrous sulphate. Properties.—Physical.—A colorless, odorless gas, having a sweetish taste ; soluble in H„0, more so in alcohol. Under a pressure of 30 atmo- spheres, at 0° (32° F.), it forms a colorless, mobile liquid, which, when dissolved in carbon disulphide and evaporated in vacua, produces a cold of -140° (- 220° F.) Chemical.—It is decomposed by a red heat and by the continuous passage of electric sparks. It is not combustible, but is, after oxygen, the best supporter of combustion known. Physiological.—Although, owing to the readiness with which N20 is decomposed into its constituent elements, and the nature and relative pro- portions of these elements, it is capable of maintaining respiration longer than any gas except oxygen or air; an animal will live for a short time only in ah atmosphere of pure nitrous oxide. When inhaled, diluted with air, it produces the effects first observed by Davy in 1799 : first an exhil- aration of spirits, frequently accompanied by laughter, and a tendency to muscular activity, the patient sometimes becoming aggressive ; afterward there is complete anaesthesia and loss of consciousness. It has been much used, by dentists especially, as an anaesthetic in operations of short dura- tion, and in one or two instances anaesthesia has been maintained by its use for nearly an hour. A solution in water under pressure, containing five volumes of the gas, is sometimes used for internal administration. NITROGEN TETROXIDE. 75 Nitrogen Dioxide. Nitric oxide—NO—Molecular weight = 30—Sp. gr. — 1.039.4—Dis- covered by Hales in 1772. Preparation.—By the action of copper on moderately diluted nitric acid in the cold : 3Cu + 8N03H — 3(N03)2Cu -f- 4H20 + 2NO ; the gas being collected after displacement of air from the apparatus. Properties.—A colorless gas, whose odor and taste are unknown ; very sparingly soluble in H20 ; more soluble in alcohol. It combines with O when mixed with that gas or with air, to form the reddish-brown nitrogen tetroxide. It is absorbed by solution of ferrous sulphate, to which it communicates a dark brown or black color. It is neither combustible nor a good supporter of combustion, although ignited C and P continue to burn in it, and the alkaline metals, when heated in it, combine with its O with incandescence. Nitrogen Trioxide. Nitrous anhydride.—N203—76. Has not been obtained in a condition of purity. A mixture of 95 per cent, of N„03 with 5 per cent, of N20 may, however, be obtained by decomposing liquefied niti'ogen tetroxide with a small quantity of H20 at a low temperature : 4N02 + H20 = 2N03H + N203. This is a dark indigo-blue liquid, which, boiling at about 0° (32° F.), is partly decom- posed. Nitrogen Tetroxide Nitrogen peroxide—Hyponitric acid—Nitrous fumes—NO—Molec- ular weight = 46—Sp. gr. = 1.58A. (at 154°<7.)—Boils at 22° (71°.G F.) —Solidifies at 9° (15°.8 F). Preparation.—(1.) By mixing one volume O with two volumes NO ; both dry and ice-cold. (2.) By heating perfectly dry lead nitrate, O being also produced : 2(N03)2Pb = 2PbO + 4N02 + 02. (3.) By dropping strong nitric acid upon a red-hot platinum surface. Properties.—When pure and dry it is an orange-yellow liquid at the ordinary temperature ; the color being darker the higher the temperature. The red fumes which are produced when nitric acid is decomposed by starch or by a metal consist of N02 mixed with N203. It dissolves in nitric acid, forming a dark yellow liquid, which is blue or green if N203 be also present. With SO„ it combines to form a solid, crystalline compound, which is sometimes produced in the manufacture of S04H2 and known as 'ead chamber crystals. A small quantity of H20 decomposes it into NOsH and N203, which latter colors it green or blue ; a larger quantity of H20 iecomposes it into N03H and NO. By bases it is transformed into a mixture of nitrite and nitrate : 2NO,, + 2KHO = N02K 4- NO,K + H20. It is an energetic oxydant, for which it is largely used. With certain organic substances it does not behave as an oxydant, but becomes 76 MANUAL OF CHEMISTRY. substituted as an univalent radical; thus with benzol it forms nitro-benzol: CeH6(N03). Toxicology.—The brown fumes given off during many processes, in which nitric acid is decomposed, are dangerous to life. All such opera- tions, when carried on on a small scale, as in the laboratory, should be conducted under a hood or some other arrangement, by which the fumes are carried into the open air. When, in industrial processes, the volume of gas formed becomes such as to be a nuisance when discharged into the air, it should be utilized in the manufacture of S04H3 or absorbed by H30 or an alkaline solution. An atmosphere contaminated with brown fumes is more dangerous than one containing Cl, as the presence of the latter is more immediately annoying. At first there is only coughing, and it is only two to four hours later that a difficulty in breathing is felt, death occurring in ten to fifteen hours. At the autopsy the are found to be extensively disorganized and filled with black fluid. Even air containing small quantities of brown fumes, if breathed for a long time, produces chronic disease of the respiratory organs. To prevent such accidents, thorough ventilation in locations where brown fumes are liable to be formed is imperative. In cases of spilling nitric acid, safety is to be sought in retreat from the apartment until the fumes have been replaced by pure air from without. Nitrogen Pentoxide. Nitric anhydride—N„06—Molecular weight — 108—Fuses at 30° (86° F) —Boils at 47° (116°.G F). Preparation.—(1.) By decomposing dry silver nitrate with dry Cl in an apparatus entirely of glass: 4N03Ag + 2Cla = 4AgCl + 2Na06 + Oa. (2.) By removing water from fuming nitric acid with phosphorus pent- oxide : 6N03H + P305 = 2PO H3 + 3Na06. Properties.—Prismatic crystals at temperatures above 30° (86° F.). It is very unstable, being decomposed by a heat of 50° (122° F.) ; on contact with H„0, with which it forms nitric acid ; and even spontaneously. Most substances which combine readily with O, remove that element from Na06. Nitrogen Acids, Three are known, either free or in combination, corresponding to the three oxides containing uneven numbers of O atoms: N„0 + H20 = 2N0H—Hyponitrous acid. N203 + HaO = 2N02H—Nitrous acid. Na05 + H20 = 2N03H—Nitric acid. Hyponitrous acid—NOH — 31—Known only in combination. Silver hyponitrite is formed by reduction of sodium nitrate by nascent H and decomposition with silver nitrate. Nitrous acid—N02H—47—has not been isolated, although its salts, the nitrites, are well-defined compounds : NOaM' or (NOa)a M". NITRIC ACID. 77 Nitric Acid. Aquafortis—Hydrogen nitrate—Acidum nitricum—U. S.; Br.—NO H —63. Preparation.—(1.) By the direct union of its constituent elements under the influence of electric discharges. (2.) By the decomposition of an alkaline nitrate by strong S04H„. With moderate heat a portion of the acid is liberated : 2N03Na -f S04H2 = S04NaH + N03Na + N03H, and at a higher temperature the remainder is given off: N03Na + S04NaH = S04Na2 + N03H. This is the reaction used in the manufacture of N03H. Varieties.—Commercial—a yellowish liquid, very impure, and of two degrees of concentration : single aquafortis; sp. gr. about 1.25 = 39$ N03H ; and double aquafortis ; sp. gr. about 1.4 = 64$ N03H. Fuming—a reddish yellow liquid, more or less free from impurities; charged with oxides of nitrogen. Sp. gr. about 1.5. Used as an oxidizing agent. C. P.—a colorless liquid, sp. gr. 1.522, which should respond favorably to the tests given below. Acidum nitricum, U. S. ; Br.—a colorless acid, of sp. gr. 1.42 = 70$ no3h. Acidum nitricum dilutum, U. S. ; Br.—the last mentioned, diluted with H20 to sp. gr. 1.059 = 10$ NO„H (U. S.), or to sp. gr. 1.101 = 17.44$ N03H (Br.). Properties.—Physical.—The pure acid is a colorless liquid ; sp. gr. 1.522 ; boils at 86° (186°.8 F.) ; solidifies at —40° (—40° F.) ; gives off white fumes in damp air ; and has a strong acid taste and reaction. The sp. gr. and boiling-point of dilute acids vary with the concentration. If a strong acid be distilled, the boiling-point gradually rises from 86° (186°.8 F.) until it reaches 123° (253°. 4 F.), wdien it remains constant, the sp gr. of distilled and distillate being 1.42 = 70$ N03H. If a weak acid be taken originally the boiling-point rises until it becomes stationary at the same point. Chemical.—When exposed to air and light, or when heated to redness, nq3h is decomposed into N02 ; H20 and O. Nitric acid is a valuable oxydant; it converts I, P, S, C, B, and Si or their lower oxides into their highest oxides; it oxidizes and destroys most organic substances, although with some it forms products of substitution. Most of the metals dissolve in N03H as nitrates, a portion of the acid being at the same time decomposed into NO and H20 : 4N03H + 3Ag = 3N03Ag + NO + 2H,0. The so-called “ noble metals,” gold and platinum, are not dissolved by either N03H or HC1, but dissolve as chlorides in a mixture of the two acids, called aqua regia. In this mixture the two acids mutually decompose each other according to the equations: N03H + 3HC1 = 2H20 -t- NOC1 + Cl2 and 2N03H + 6HC1 = 4H20 + 2N0C12 + Cl2 with formation of nitrosyl chloride, NOC1, and bichloride N0C12 ; and nascent Cl; the last named combining with the metal. When N03H is decomposed by zinc or iron or in the porous cup of a Grove battery, N203 and N02 are formed and dissolve in the acid, which is colored dark yellow, blue or green. An acid so charged is known as nitroso-nitric acid. Nitric acid is monobasic. Impurities.— Oxides of Nitrogen render the acid yellow, and decolorize 78 MANUAL OF CHEMISTRY. potassium permanganate when added to the dilute acid. Sulphuric acid produces cloudiness when BaCl2 is added to the acid, diluted with two volumes of H20. Chlorine, iodine cause a white ppt. with NOsAg. Iron gives a red color when the diluted acid is treated with ammonium sulpliocyanate. Salts, leave a fixed residue when the acid is evaporated to dryness on platinum. Analytical Chaeactees.—(1.) Add an equal volume of concentrated S04H,, cool, and float on the surface of the mixture a solution of S04Fe. The lower layer becomes gradually colored brown, black or purple, beginning at the top. (2.) Boil in a test-tube a small quantity of HC1 containing enough sulphindigotic acid to communicate a blue color, add the suspected solution and boil again ; the color is discharged. (3.) If acid neutralize with KHO, evaporate to dryness, add to the residue a few drops of S04H2 and a crystal of brucine (or some sulph- anilic acid) ; a red color is produced. (4.) Add S04H2 and Cu to the suspected liquid and boil, brown fumes appear (best visible by looking into the mouth of the test-tube). The above appearances are caused by free nitric acid, but if the tests be conducted as directed a nitrate, if present, is decomposed with lib- eration of the acid. All neutral nitrates are soluble in H„0 ; some so-called basic salts are insoluble, as bismuthyl nitrate : NOa (BiO). Toxicology.—Although most of the nitrates are poisonous when taken internally in sufficiently large doses, their action seems to be due rather to the metal than to the acid radical. Nitric acid itself is one of the most powerful of corrosives. Any animal tissue with which the concentrated acid comes in contact is immediately disintegrated ; a yellow stain, afterward turning to dirty brownish, or, if the action be prolonged, an eschar, is formed. When taken internally its action is the same as upon the skin, but, owing to the more immediately important function of the parts, is followed by more serious results (unless a large cutaneous surface be destroyed). The symptoms following its ingestion are the same as those produced by the other mineral acids, except that all parts with which the acid has come in contact, including vomited shreds of mucous membrane, are colored yellow. The treatment is the same as that indicated when S04Ha or HC1 have been taken ; i.e. neutralization of the corrosive by magnesia or an alkali. Compounds of Nitrogen with the Halogens. Nitrogen chloride—NC1S—120.5—is formed by the action of excess of Cl upon NH3 or an ammoniaeal compound. It is an oily, light yellow liquid ; sp. gr. 1.653 ; has been distilled at 71° (159°.8 F.). When heated to 96° (204°.8 F.), when subjected to concussion, or when brought in contact with phosphorus, alkalies or greasy matters it is decomposed, with a violent explosion, into one volume N and three volumes Cl. Nitrogen bromide—NBra—254—has been obtained as a reddish brown, syrupy liquid, very volatile, and resembling the chloride in its jxroperties, by the action of potassium bromide upon nitrogen chloride. Nitrogen iodide—NI,—395—When iodine is brought in contact with ammonium hydrate solution, a dark brown or black powder, highly PHOSPHOKUS. 79 explosive when dried, is formed. This substance varies in composition according to the conditions under which the action occurs ; sometimes the iodide alone is formed ; under other circumstances it is mixed with compounds containing N, I and H. PHOSPHORUS. Symbol = P—Atomic weight — 31—Molecular weight — 124—Sp. gr. of vapor = 4.2904 A—Name from ws = light, 0 C ,H 0O (’s,OiHi 9 c10h22o CioOjH2o CnHo4 c,2h26 c14h30 C14O.H28 But the arrangement in homologous series does more for us than this. The properties of substances in the same series vary in regular gradation according to their position in the series ; thus, in the series of alcohols in the above table, the boiling-points of the first six are, 66.5.°, 78.4°, 96.7°, 111.7°, 132.2°, 153.9° ; from which it will be seen that the boiling-point of any one of them can be determined, with a maximum error of 3°, by taking the mean of those of its neighbors above and below. In this way we may prophecy, to some extent, the properties of a wranting member in a series before its discovery. The terms of any homologous series must all have the same constitution, i.e., their constituent atoms must be sim- ilarly arranged within the molecule. Isomerism—Metamerism—Polymerism. Two substances are said to be isomeric, or to be isomeres of each other, when they have the same centesimal composition. If, for instance, we analyze acetic acid and methyl formiate, we find that each body consists of C, O and H, in the following proportions : Carbon 40 24 = 12 x 2 Oxygen 53.33 32 = 16 x 2 Hydrogen 6.67 4= 1x4 100.00 60 CLASSIFICATION OF ORGANIC SUBSTANCES. 109 This similarity of centesimal composition may occur in two ways : the two substances may each contain in a molecule the same numbers of each kind of atom ; or one may contain in each molecule the same kind of atoms as the other, but in a higher multiple. In the above instance, for example, each substance may have the composition C2H402; or one may have that formula and the other, C6H1206, or C2H 02 x 3. In the former case the substances are said to be metameric, in the latter polymeric. Whether two substances are metameric or polymeric can only be determined by ascer- taining the weights of their molecules, which is usually accomplished by determining the sp. gr. of their vapors (see p. 14). The sp. gr. of the vapor of acetic acid is the same as that of methyl formiate, and, consequently, each substance is made up of molecules, each containing C2H402. But the two substances differ from each other greatly in their properties, and their differences are at once indicated by their typical or graphic formulae : moyjo (CHO)') Q. (CH 3)'fU’ and or graphically : CH3 COOH H I cooch3. and Classification of Organic Substances. As the compounds of the other elements may be divided into classes, such as acids, bases, salts, etc., according to their chemical functions, the compounds of carbon also arrange themselves into certain well-defined groups, called by the French chemists functions—a term which it would be well to introduce into our own nomenclature. The properties of the functions of organic substances do not depend, like those of other com- pounds, upon the kind of atoms of which they are composed, but rather upon the arrangement of the atoms within the molecule ; and in this point we find the most prominent distinction between organic and mineral sub- stances. Arsenic, for instance, is poisonous in whatever form of chemical combination it may be, provided only that it can be rendered soluble, and therefor capable of absorption. Carbon, oxygen, and hydrogen, on the other hand, combine with each other to form substances having the most diverse action upon the economy—the fats and sugars, ordinary articles of food, on the one hand, and substances having such marked toxic powers as ether and oxalic acid, on the other—the differences between the prop- erties of the two substances depending entirely upon the numbers and positions in the molecule of the same kind of atoms. 110 MANUAL OF CIIEMISTKY. SATURATED HYDROCARBONS AND THEIR DERIVATIVES. FIRST SERIES OF HYDROCARBONS. Series CnHm + 8. A hydrocarbon is a compound of carbon and hydrogen only. It is satu- rated when all the valences of all the constituent atoms are satisfied. The hydrocarbons of this series at present known are the following : Name. Formula. Specific gravity of liquid. Boiling- point. Cen- tigrade. Name. Formula. Specific gravity of liquid. Boiling- point. Cen- tigrade. Methyl hydride... Ethyl hydride Propyl hydride... CH3H c2h5h c3h7h Nonyl hydride.... Decyl hydride TJndecyl hydride.. C,H19H !0.741 at 18° Ci0H21H 0.757 at 18° 0.766 at 18° 136°-138° 158°-162° 180°-182° Butyl hydride O4H9H 0.600 at 0° 0° Dodecyl hydride.. 0.778 at 18° 198°-200° Amyl hydride O.HnH 0.628 at 18° 30° Tridecyl hydride.. C,3H27H 0.796 at 18° 218° 220° Hexyl hydride c6h13ii 0.669 at 18° 68° Tetradecyl hydride C14H29H 0.809 at 18° 236°-240° Heptyl hydride C711i5H 0.690 at 18° 92°-94° Pentadecvlhydride C15H31H 0.825 at 18° 258°-262° Octyl hydride .... c8h17h 0.726 at 18° 116°-118’ Hexadecyl hydride, C16H33H i 1 about 280° They form an homologous series whose general formula is C„H,,n + s, and are known as paraffines from their stability (parum = little, affinis = affinity). Their constitution is expressed typically by the formula C H ) n 2n H ( the radicals CnH2„ + „ of which they are the hydrides, are designated as the radicals of the monoatomic alcohols. Corresponding to the higher terms of the series (those above the third) there are one or more isomeres, which may be arranged in four classes. (1.) The normal or regularly formed series, in which each C atom is linked to two other C atoms. (2.) Those in which one C atom is linked to three others. (3.) Those in which two G atoms are each linked to three others. (4.) Those in which one C atom is linked to four others. The constitution of these series is explained by the graphic formulae : ”h9o nH90 ”h9o mh9o 'ho 'HO | 'ho 1 'ho 1 'ho 1 'HO 1 'HO | 'ho 'HO—0—H 'ho 'ho 1 'ho—o— o'h 1 'HO—0—H 'HO-0—H 'ho j 'ho 'HO 'HO 'ho (•?) ('8) (’5) (•X) As all of these compounds are saturated they are incapable of being modified by addition, i.e. by the simple insertion of other atoms into the FIRST SERIES OF HYDROCARBONS. molecule ; they may, however, be modified by substitution, i.e. by the re- moval of one or more of their atoms and the substitution therefor of an atom or atoms of different kind. Methyl hydride—Methane—Marsh-gas—Light carburetted hydrogen— Fore-damp—CHt—16—is given oft“ in swamps as a product of decomposi- tion of vegetable matter, in coal mines, and in the gases issuing from the earth in the vicinity of petroleum deposits. Coal-gas contains it in the proportion of 36-50 per cent. It may be prepared by strongly heat- ing a mixture of sodium acetate with sodium hydrate and quicklime. It is a colorless, odorless, tasteless gas ; very sparingly soluble in 1I20 ; sp. gr. 0.559A. At high temperatures it is decomposed into C and H. It burns in air with a pale yellow flame. Mixed with air or O it explodes violently on contact with flame, producing water and carbon dioxide ; the latter constituting the after-damp of miners. It is not affected by Cl in the dark, but under the influence of diffuse daylight one or more of the H atoms are displaced by an equivalent quantity of Cl. In direct sunlight the substitution is accompanied by an explosion. Petroleum.—Crude petroleum differs in composition and in physical properties in the products of different wells, even in the same section of country. It varies in color from a faintly yellowish tinge to a dark b'rown, nearly black, with greenish reflections. The lighter-colored varie- ties are limpid, and the more highly colored of the consistency of thin syrup. The sp. gr. varies from 0.74 to 0.92. Crude petroleums contain all the hydrocarbons mentioned in the list on p. 110 (the first of the series, being found in the gases accompanying petroleum, is also held in solution by the oil under the pressure it supports in natural pockets), be- sides hydrocarbons of the olefine series, and of the benzol series. The crude oil is highly inflammable, usually highly colored, and is pre- pared for its multitudinous uses in the arts by the processes of distillation and refining. The distillation is usually so conducted as to divide the product into four parts: Naphtha Sp. gr. 0.700-12-15$ Benzine Sp. gr. 0.730— 9-12$ Burning oil Sp. gr. 0.783—60$ Residuum and loss 13-1!% The naphtha, or petroleum ether, is further separated by distillation into other products : lihigoline, a highly inflammable liquid; sp. gr. about 0. GO, which boils at about 21° (70° F.). It is used to produce cold by its rapid evaporation, but its low boiling-point and inflammability render its use dangerous. Gasoline; sp. gr. about 0.G3-0.61; boils at about 76° (170° F.). Benzine or benzoline, sp. gr. about 0.73 ; boils at about 148° (298° F.), and is largely used in the arts as a solvent. It must not be confounded with benzol or benzene, CGHfi (q. v.). The most important product of petroleum is that portion which distils above 183° (361° F.) and which constitutes kerosene, and other oils used for burning in lamps. An oil to be safely used for burning in lamps should not “flash,” or give off inflammable vapor, below 60° (140° F.); and should not burn at temperatures below 65°.5 (150° F.). From the residue remaining after the separation of the kerosene, a variety of other products are obtained. Lubricating oils, of too high boil- ing-point for use in lamps. Paraffine, a white, crystalline solid, fusible at 45°-G5° (113°-149° F.), which is used in the arts for a variety of pur- poses formerly served by wax, such as the manufacture of candles. In the laboratory it is very useful for coating the glass stoppers of bottles, and for 112 MANUAL OF CHEMISTRY. other purposes, as it is not affected by acids or by alkalies. It is odorless, tasteless, insoluble in H20 and in cold alcohol; soluble in boiling alcohol and in ether, fatty and volatile oils, and mineral oils. It is also obtained by the distillation of certain varieties of coal, and is found in nature in fossil wax or ozocerite. The products known as vaseline, petrolatum (U. S.), cosmoline, etc., which are now so largely used in pharmacy and perfumery, are mixtures of paraffine and the heavier petroleum oils. Like petroleum itself, its various commercial derivatives are not definite compounds, but mixtures of the hydrocarbons of this series. Haloid Derivatives of the Paraffines. By the action of Br upon the paraffines, or by the action of HC1, HBr or HI upon the corresponding hydrates, compounds are obtained in which one of the H atoms of the hydrocarbon has been replaced by an atom of Cl, Br or I: C2H6 + Br2 = C2H5Br + HBr, or C2H5OH + HC1 = C2H5C1 + H20. These compounds may be considered as the chlorides, bromides or iodides of the alcoholic radicals ; and are known as haloid ethers. When Cl is allowed to act upon CH(, it replaces a further number of H atoms until finally carbon tetrachloride, CC14, is produced. Consider- ing marsh gas as methyl hydride, CH3,H, the first product of substitution is methyl chloride, CH3,C1; the second monochlormethyl chloride, CH2C1, Cl; the third dichlormethyl chloride, or chloroform, CHC12C1; and the fourth carbon tetrachloride, CC14. Similar derivatives are formed with Br and I and with the other hydro- carbons of the series. Methyl chloride—CH3C1 —50.5—is a colorless gas, slightly solu- ble in H20, and having a sweetish taste and odor. It is obtained by dis- tilling together S04H2, sodium chloride and methyl achohol. It may be condensed to a liquid which boils at —22° ( —7°.6F.). It burns with a greenish flame. Heated with potassium hydrate it is converted into methyl alcohol. Monochlormethyl chloride—Methene chloride—Dichloromethane— Methxylene chloride—Chloromethyl—CH2C1,C1—85—is obtained by the action of Cl upon CH3C1; or by shaking an alcoholic solution of chloro- form with powdered zinc and a little ammonium hydrate. In either case the product must be purified. It is a colorless, oily liquid, boils at 40°-42° (104°-107°.6 F.) ; sp. gr. 1.36 ; its odor is similar to that of chloroform ; it is very slightly soluble in H20 ; and is not inflammable. Like most of the chlorinated derivatives of this series, it is possessed of anaesthetic powers. Its use as an anaes- thetic is attended with the same (if not greater) danger as that of chloro- form. Dichlormethyl chloride—Methenyl chloride—Formyl chloride— Trichloromethane—Chloroform—Chloroformum (U. S., Br.)—CH„C12,C1— 120.5—is obtained by heating in a capacious still, 35-40 litres (9-11 gall.) of H20, adding 5 kilos (11 lbs.) of recently slacked lime and 10 kilos (22 lbs.) of chloride of lime ; 2.5 kilos (2|- qts.) of alcohol are then added and the temperature quickly raised until the product begins to distil, when the fire is withdrawn, heat being again applied toward the end of the reaction. The crude chloroform so obtained is purified, first by agitation HALOID DERIVATIVES OF THE PARAFFINES. 113 with S04H2, then by mixing with alcohol and recently ignited potassium carbonate, and distilling the mixture. It is a colorless, volatile liquid, having a strong, agreeable, ethereal odor, and a sweet taste ; sp. gr. 1.497 ; very sparingly soluble in H20; miscible with alcohol and ether in all proportions ; boils at 60°.8 (141°.4 F.). It is a good solvent for many substances insoluble in H„0, such as phos- phorus, iodine, fats, resins, caoutchouc, gutta-percha and the alkaloids. It ignites with difficulty, but burns from a wick with a smoky, red flame, bordered with green. It is not acted on by S04Ho, except after long contact, when HC1 is given off. In direct sunlight Cl converts it into CC14 and HC1. The alkalies in aqueous solution do not act upon it, but when heated with them in alcoholic solution it is decomposed with formation of chloride and formiate of the alkaline metal. When perfectly pure it is not altered by exposure to light ; but if it contain compounds of N, even in very minute quantity, it is gradually decomposed by solar action into HC1, Cl and other substances. Impurities.—Alcohol, if present in large amount, lowers thesp. gr. of the chloroform, and causes it to fall through H,0 in opaque, pearly drops. If present in small amount it produces a green color with ferrous dinitrosul- phide (obtained by acting on ferrous chloride with a mixture of potassium nitrate and ammonium hydrosulphide). Aldehyde produces a brown color when CHC13 containing it is heated with liquor potassae. Hydrochloric acid reddens blue litmus, and causes a white precipitate in an aqueous solution of silver nitrate shaken with chloroform. Methyl and empyreu- matic compounds are the most dangerous of the impurities of chloroform. Their absence is recognized by the following characters: (1.) When the chloroform is shaken with an equal volume of colorless SO,H.., and allowed to stand 24 hours ; the upper (chloroform) layer should be perfectly color- less, and the lower (acid) layer colorless or faintly yellow. (2.) When a small quantity is allowed to evaporate spontaneously, the last portions should have no pungent odor, and the remaining film of moisture should have no taste or odor other than those of chloroform. Analytical Characters.—(1.) An alcoholic solution of CHC13, to which a little alcoholic solution of potash and 2-3 drops of aniline have been added develops, when gently warmed, the peculiar, disagreeable odor of isobenzo- nitril. (2.) Vapor of CHC1, when passed through a red-hot tube, is decomposed with formation of HC1 and Cl, the former of which is recognized by the production of a white ppt., soluble in ammonium hydrate, in an acid solu- tion of silver nitrate, and the latter by the production of a blue color in paper moistened with starch paste and potassium iodide solution. This test does not afford reliable results when the substance tested contains a free acid and chlorides. Toxicology.—The action of chloroform varies as it is taken by the stomach or by inhalation. In the former case, owing to its insolubility, but little is absorbed, and the principal action is the local irritation of the mucous surfaces. Recovery has followed a dose of four ounces, and death has been caused by one drachm, taken into the stomach. Chloro- form vapor acts much more energetically, and seems to owe its potency for evil to its paralyzing influence upon the nerve-centres, notably upon those of the heart. While persons suffering from heart disease are particu- larly susceptible to the paralyzing effect of chloroform vapor, there are many cases recorded of death from the inhalation of small quantities, properly diluted, in which no heart lesion was found upon a post-mortem examina- 114 MANUAL OF CHEMISTRY. tion. Chloroform is apparently not altered in the system, and is elimi- nated with the expired air. No chemical antidote to chloroform is known. When it has been swallowed, the stomach-pump and emetics are indicated ; when taken by inhalation, a free circulation of air should be established about the face ; artificial respiration and the application of the induced current to the sides of the neck should be resorted to. The nature of the poison is usually revealed at the autopsy by its peculiar odor, which is most noticeable on opening the cranial and tho- racic cavities. In a toxicological analysis, chloroform is to be sought for especially in the lungs and blood. These are placed in a flask ; if acid, neutralized with sodium carbonate ; and subjected to distillation at the temperature of the water-bath. The vapors are passed through a tube of difficultly fusible glass ; at first the tube is heated to redness for about an inch of its length, and test No. 2 applied to the issuing gas. The tube is then allowed to cool, and the distillate collected in a pointed tube, from the point of which any CHC13 is removed by a pipette and tested according to No. 1 above. Carbon tetrachloride—Chlorocarbon—CC14—154—is formed by the prolonged action, in sunlight, of Cl upon CHSC1 or CHC13; or more rapidly, by passing Cl, charged with vapor of carbon disulphide, through a red-hot tube, and purifying the product. It is a colorless, oily liquid, insoluble in II„0 ; soluble in alcohol and in ether; sp. gr. 1.56 ; boils at 78° (172°.4 F.). Its vapor is decomposed at a red heat into a mixture of the dichloride, C2C14, trichloride, C2Clc, and free Cl. Methyl bromide—CH3Br—95.—A colorless liquid ; sp. gr. 1.664 ; boils at 13° (55.4° F.); formed by the combined action of P and Br on methyl hydrate. Dibromomethyl bromide'—Methenyl bromide—Formyl bromide— Bromoform—CHBr„, Br—253—is prepared by gradually adding Br to a cold solution of potassium hydrate in methyl alcohol, until the liquid begins to be colored ; and rectifying over calcium chloride. A colorless, aromatic, sweet liquid ; sp. gr. 2.13 ; boils at 150°-152° (302°-306° F.); solidifies at —9° (15°.8 F.); sparingly soluble in H20 ; soluble in alcohol and ether. Boiled with alcoholic potash it is decom- posed in the same way as is CHOI,,. Its physiological action is similar to that of CHC13. It occurs as an impurity of commercial Br, accompanied by carbon tetrabromide, CBr4. Methyl iodide—CH3I—142—a colorless liquid, sp. gr. 2.237 ; boils at 45° (113° F.) ; burns with difficulty, producing violet vapor of iodine. It is prepared by a process similar to that for obtaining the bromide ; and is used in the aniline industry. Diiodomethyl iodide—Methenyl iodide—Formyl iodide—Iodoform— Iodoformum, U. S.—CHI„I—394.—Formed, like chloroform and bromoform, by the combined action of potash and the halogen upon alcohol; it is also produced by the action of I upon a great number of organic substances, and is usually prepared by heating a mixture of alkaline carbonate, H20, I and ethylic alcohol, and purifying the product by recrystallization from alcohol. Iodoform is a solid, crystallizing in yellow, hexagonal plates, which melt at 115°-120° (239°-248° F.). It maybe sublimed, a portion being decomposed. It is insoluble in water, acids, and alkaline solutions : solu- ble in alcohol, ether, carbon disulphide, and the fatty and essential oils: MONOATOMIC ALCOHOLS. 115 the solutions, when exposed to the light, undergo decomposition and assume a violet-red color. It has a sweet taste and a peculiar, penetrating odor, resembling, when the vapor is largely diluted with air, that of Saffron. When heated with potash, a portion is decomposed into formiate and iodide, while another portion is carried off unaltered with the aqueous ■vapor. It contains 96.7$ of its weight of iodine. Ethyl chloride—Hydrochloric or muriatic ether—C2H5C1—64.5.—A colorless, white, ethereal liquid; boils at 11° (51°.8 F.) ; obtained by passing gaseous HC1 through ethylic alcohol to saturation and distilling over the water-bath. Ethyl bromide — Hydrobromic ether— CsH,Br —109.—A colorless, ethereal liquid; boils at 40°.7 (105°.3 F.) ; obtained by the combined action of P and Br on ethylic alcohol. Ethyl iodide—Hydriodic ether—C2H5I—156—is prepared by placing absolute alcohol and P in a vessel surrounded by a freezing mixture and gradually adding I; when the action has ceased, the liquid is decanted, distilled over the water-bath, and the distillate washed and rectified. It is a colorless liquid ; boils at 72°.2 (162° F.) ; has a powerful, ethereal odor ; burns with difficulty. It is largely used in the aniline industry. MONOATOMIC ALCOHOLS. Sebies C„H2n+20. The following is a list of the terms of the primary series which have been studied, and their prominent physical properties. Name. Empirical formula. Typical formula. Fusing- point. Boiling- point. Specific gravity. Methyl hydrate ch4o ch3 H [° . , 66°.5 0 814 Ethyl hydrate c2h6o C2H5 H [° . • 78°.3 0 8095 Propyl hydrate c3h„o c3h, H 1° . . 96°.7 0 820 Butyl hydrate C4H1 oO C4Ha H 1° .. 114°.7 0 817 Amyl hydrate c6h12o c6h,, H .0 -20° 132° Hexyl hydrate c„huo c6h13 H .0 .. 150° 0 O CQ CO Heptyl hydrate c7h16o c7h16 H 0 .. 168° Octyl hydrate CsH! sO c«h17 H [° .. 186° Nonyl hydrate C9H20O c9hi9 H 0 .. 204° Decyl hydrate c10h32o C,oH2I H 0 Cetyl hydrate C16H340 C18Hs3 H ■0 49° .... Ceryl hydrate c27h56o Oa7H.55 H 0 79° — Myricyl hydrate C30H62O CaoHci H 0 85° ... 116 MANUAL OF CHEMISTRY. The name alcohol, formerly applied only to the substance now pop- ularly so called, has gradually come to be used to designate a large class of important bodies, of which vinic alcohol is the representative. These substances are mainly characterized by their power of entering into double decomposition with acids, to form neutral compounds, called com- pound ethers, water being at the same time formed, at the expense of both alcohol and acid. They are the hydrates of the alcoholic radicals, and as such resemble the metallic hydrates, while the compound ethers are the coun- ter parts of the metallic salts: (0 A) l o + 1 o - I o + H1 o H ) + H(U_ (C2H6) [ u + H j u Ethyl hydrate. Acetic acid. Ethyl acetate. Water. K|o+(C^O)|o=(C.H.O)|o,+ HiJo Potassium hydrate. Acetic acid. Potassium acetate. Water. As the metallic hydrates may be considered as formed by the union of one atom of the metallic element with a number of groups OH', corre- sponding to its valence, so the alcohols are formed by union of an unoxi- dized radical with a number of groups OH', equal to or less than the num- ber of free valences of the radical. When the alcohol contains one OH, it is designated as monoatomic; when two, diatomic; when three, tri- atomic, etc. The simplest alcohols are those of this series derivable from the saturated hydrocarbons, and having the general formula CnH2„+20, or C„H2n+1OH. They may be formed synthetically : (1.) By acting upon the corresponding iodide with potassium hydrate : C2H5I 4- KHO = KI + C.,H. OH. (2.) From the alcohol next below it in the series, by direct addi- tion of CH2, only, however, by a succession of five reactions. (3.) By the action of SO+Ha and H20 upon the corresponding hydrocarbon of the se- ries C„H2„. The saturated monoatomic alcohols are, however, not limited to one corresponding to each alcoholic radical. There exist—corresponding to the higher alcohols—a number of substances having the same centesimal com- position and the same alcoholic properties, but differing in their physical characters and in their products of decomposition and oxidation. These isomeres have been the subject of much careful study of late years. It has been found that the molecules of methyl, ethyl, and other higher alco- hols are made up of the group (CH2OH)' united to H or to CnH2n+1, thus : CH„OH H CHOH I ch3 ch2oh I c2h6 Methyl alcohol. Ethyl alcohol. Propyl alcohol. and all monoatomic alcohols containing this group, CH„OH, have been designated as primary alcohols. Isomeric with these are other bodies, MONO ATOMIC ALCOHOLS. 117 which, in place of the group (CH2OH)', contain the group (CHOH)", and are distinguished as secondary alcohols. Thus we have : (CH2OH)' I CaHB c3h8o ch3 (CHOH)" ch3 C3HhO Primary propyl alcohol. Secondary propyl alcohol. And further, other isomeric substances are known which contain the group (COH)'", and which are called tertiary alcohols, thus : (CHaOH)' I c4h9 C3Hb (CHOH)" I c2h5 c6h12o CH I (CaHB)—(COH)'" CH3 c6h12o cbh120 Primary amylic alcohol. Secondary amylic alcohol. Tertiary amylic alcohol. The alcohols of these three classes are distinguished from each other principally by their products of oxidation. The primary alcohols yield by oxidation, first an aldehyde and then an acid, each containing the same num- ber of C atoms as the alcohol, and formed, the aldehyde by the removal of Ha from the group (CHaOH), and the acid by the substitution of O for Ha in the same group, thus: CHsOH I ch3 COH cooh ch3 Ethyl alcohol. Ethyl aldehyde. Acetic acid. In the case of the secondary alcohols, the first product of oxidation is a ketone, containing the same number of C atoms as the alcohol, and formed by the substitution of O for HOH in the distinguishing group : r CHOH I ch3 cn, CO I CH, Secondary propyl alcohol. Propyl ketone or acetone. The tertiary alcohols yield by oxidation ketones or acids, whose molecules contain a less number of C atoms than the alcohol from which they are derived. But the complication does not end here ; isomeres exist corresponding to the higher alcohols, which are themselves primary alcohols, and contain the group (CHaOH/. Thus there exist no less than seven distinct sub- 118 MANUAL OF CHEMISTRY. stances, all having the centesimal composition of amyl alcohol, C6HiaO, and the properties of alcohols; and theoretical considerations point to the probable existence of an eighth. Of these eight substances, four are pri- mary, three secondary alcohols, and the remaining one a tertiary alcohol. As each of these bodies contains the group of atoms characteristic of the class of alcohol to which it belongs, it is obvious that the differences ob- served in their properties are due to differences in the arrangement of the other atoms of the molecule. Experimental evidence, which it would require too much space to discuss in this place, has led chemists to ascribe the following formulae of constitution to these isomeres. Primary amylic alcohols: CH-CH—CH—CH-CHa,OH Normal amylic alcohol. 3/CH-CH-CH„OH Active amylic alcohol of fermentation. chj-cI;>ch-ch.’°11 Inactive amylic alcohol of fermentation. CH3\ CH— C—CHa,OH cay Unknown. Secondary amylic alcohols: CH3—CH \prT OH CH—CH2/CH’0H Diethyl earbinol. CH—CH—CHa/CH’0H Methyl-propyl carbinol. CH3/CH / Methyl-isopropyl carbinol. Tertiary amylic alcohol: ch3\ CH — C,OH CH—CH / Methyl hydrate—Carbinol—Pyroxylic spirit—Wood spirit—CH..HO —32—may be formed from marsh-gas, CH3H, by first converting it into the iodide and acting upon this with potassium hydrate : CHaI + KHO = KI + CH3HO. It is usually obtained by the destructive distillation of wood. The crude wood vinegar so produced is a mixture of acetic acid and methyl alcohol with a variety of other products. The crude vinegar, separated from tarry products, is redistilled ; the first tenth of the distil- MONOATOMIC ALCOHOLS. 119 late is treated with quicklime and again distilled; the distillate treated with dilute S04H2 ; decanted and again distilled. The product, still quite impure, is the wood alcohol, wood naphtha, or pyroxylin spirit of commerce. The pure hydrate can only be obtained by decomposing a crystalline com- pound, such as methyl oxalate, and rectifying the product until the boiling- point is constant at 66°.5 (151°.7 F.). Pure methyl alcohol is a colorless liquid, having an ethei'eal and alco- holic odor, and a sharp, burning taste ; sp. gr. 0.814 at 0° ; boils at 66°.5 (151°. 7 F.) ; bunis with a p ile flime, giving less heat than that of ethylic alcohol; mixes with water, alcohol, and ether in all proportions ; is a good solvent of resinous substances, and also dissolves sulphur, phosphorus, potash, and soda. Methyl hydrate is not affected by exposure to air under ordinary cir- cumstances, but in the presence of platinum-black it is oxidized, with for- mation of the corresponding aldehyde and acid, formic acid. Hot N03H decomposes it with formation of nitrous fumes, formic acid and methyl nitrate. It is acted upon by S04H2 in the same way as ethyl alcohol. The organic acids form methyl ethers with it. With HC1 under the in- fluence of a galvanic current, it forms an oily substance having the com- position CJI^CIO. Methylated spirit is ethyl alcohol containing sufficient wood spirit to render it unfit for the manufacture of ardent spirits, by reason of the dis- gusting odor and taste which crude wood alcohol owes to certain empy- reumatic products which it contains. Spirits so treated are not subject to the heavy duties imposed upon ordinary alcohol, and are, therefor, largely used in the arts and for the preservation of anatomical preparations. It contains one-ninth of its bulk of wood naphtha. Ethyl hydrate—Ethylic alcohol—Methyl carbinol—Vinic alcohol—Al- cohol—Spirits of wine—C2H5HO—46. Preparation.—Industrially alcohol and alcoholic liquids are obtained from substances rich in starch or glucose. The manufacture of alcohol consists of three distinct processes : 1st, the conversion of starch into sugar ; 2d, the fermentation of the saccharine liquid ; 3d, the separation, by distillation, of the alcohol formed by fer- mentation. The raw materials for the first process are malt and some sub- stance (grain, potatoes, rice, corn, etc.) containing starch. Malt is barley which has been allowed to germinate, and, at the proper stage of germina- tion, roasted. During this growth there is developed in the barley a peculiar nitrogenous principle called diastase. The starchy material is mixed with a suitable quantity of malt and water, and the mass maintained at a temperature of 65°-70° (149°-158° F.) for two to three hours, during which the diastase rapidly converts the starch into dextrin, and this in turn into glucose. The saccharine fluid, or wort, obtained in the first process, is drawn off, cooled, and yeast is added. As a result of the growth of the yeast-plant, a complicated series of chemical changes take place, the principal one of which is the splitting up of the glucose into carbon dioxide and alcohol: C6H1205 = 2C2H5OH + 2CO„. There are formed at the same time small quantities of glycerin, succinic acid, and propyl, butyl, and amyl alcohols. An aqueous fluid is thus obtained which contains 3-15 per cent, of alcohol; this is then separated by the third process, that of distillation and rectification. The apparatus used for this purpose has been so far perfected that by a single distillation an alcohol of 90-95 per cent, can be obtained. 120 MANUAL OF CHEMISTRY. In some cases alcohol is prepared from fluids rich in glucose, such as grape-juice, molasses, syrup, etc. ; in such cases the first process becomes unnecessary. Commercial alcohol always contains H20, and when pure or absolute alcohol is required, the commercial product must be mixed with some hy- groscopic solid substance, such as quicklime, from which it is distilled after having remained in contact twenty-four hours. Fermentation.—This term, derived from fervere = to boil, was origi- nally applied to alcoholic fermentation, by reason of the bubbling of the saccharine liquid caused by the escape of C02 ; subsequently it came to be applied to all decompositions similarly attended by the escape of gas. At present it is used by many authors to apply to a number of hetero- geneous processes; and some writers distinguish between “true” and “ false ” fermentation. It is best, we believe, to limit the application of the term to those decompositions designated as true fermentations. Fermentation is a decomposition of an organic substance, produced by the processes of nutrition of a low form of animal or vegetable life. The true ferments are therefor all organized beings, such as torula cere- visice, producing alcoholic fermentation ; penicillium glaucum, producing lactic acid fermentation ; and mycoderma aceti, producing acetic acid fer- mentation. The false fermentations are not produced by an organized body, but by a soluble, unorganized, nitrogenous substance, whose method of action is as yet imperfectly understood. They may be, therefor, designated by the term cryptolysis. Diastase, pepsin and trypsin are cryptolytes. Properties.—Alcohol is a thin, colorless, transparent liquid, having a spirituous odor, and a sharp, burning taste; sp. gr. 0.8095 at 0°, 0.7939 at 15° (59° F.) ; it boils at 78°.5 (173°.3 F.), and has not been solidified; at temperatures below —90° ( — 130° F.) it is viscous. It mixes with water in all proportions, the union being attended by elevation in temperature and contraction in volume (after cooling to the original temperature). It also attracts moisture from the air to such a degree that absolute alcohol only remains such for a very short time after its preparation. It is to this power of attracting 1I20 that alcohol owes its preservative power for animal substances. It is a very useful solvent, dissolving a number of gases, most of the mineral and organic acids and alkalies, most of the chlorides and carbonates, some of the nitrates, all the sulphates, essences, and resins. Alcoholic solutions of fixed medicinal substances are called tinctures ; those of volatile principles, spirits. The action of oxygen upon alcohol varies according to the conditions. Under the influence of energetic oxidants, such as chromic acid, or, when alcohol is burned in the air, the oxidation is rapid and complete, and is attended by the extrication of much heat, and the formation of carbon dioxide and water : C.,11,,0 -f 30, = 2CO, + 3H,,0. Mixtures of air and vapor of alcohol explode upon contact with flame. If a less active oxidant be used, such as platinum-black, or by the action of atmospheric oxygen at low temperatures, a simple oxidation of the alcoholic radical takes place, with formation of acetic acid - jj \ O + 02 = 2 jj r O + H,0, a reaction which is utilized in the manufacture of acetic acid and vinegar. If the oxidation be still further limited, aldehyde is formed : 2C„HrO + 02 = + 2H20. If vapor of alcohol be passed through a tube filled with platinum sponge and heated to redness, or if a coil of heated platinum wire be introduced into an atmosphere of alcohol vapor, the products of MONO ATOMIC ALCOHOLS. 121 oxidation are quite numerous : among them are water, ethylene, aldehyde, acetylene, carbon monoxide, and acetal. Heated platinum wire introduced into vapor of alcohol continues to glow by the heat resulting from the oxi- dation, a fact which has been utilized in the thermocautery. Chlorine and bromine act energetically upon alcohol, producing a num- ber of chlorinated and brominated derivatives, the final products being chloral and bromal (q. v.). If the action of Cl be moderated, aldehyde and HC1 are first produced. Iodine acts quite slowly in the cold, but old solu- tions of I in alcohol (tr. iodine) are found to contain HI, ethyl iodide, and other imperfectly studied products. In the presence of an alkali, I acts upon alcohol to produce iodoform. Potassium and sodium dissolve in alcohol with evolution of H ; upon cooling, a white solid crystallizes, which is the double oxide of ethyl and the alkaline metal. Nitric acid, aided by a gentle heat, acts violently upon alcohol, producing nitrous ether, brown fumes, and products of oxidation. For the action of other acids upon alcohol see the corresponding ethers. The hydrates of the alkaline metals dissolve in alcohol, but react upon it slowly ; the solution turns brown and contains an acetate. If alcohol be gently heated with NOsH and nitrate of silver or of mercury, a gray precipitate falls, which is silver or mercury fulminate. Varieties.—It occurs in different degrees of concentration : absolute alcohol is pure alcohol, C„HpO. It is not purchasable and must be made as required ; the so-called absolute alcohol of the shops is rarely stronger that 98 per cent. Alcohol (U. S.), sp. gr. 0.820, contains 94 per cent, by volume, and spiritus rectificatus (Br.), sp. gr. 0.838, contains 84 per cent. This is the ordinary rectified spirit used in the arts. Alcohol dilutum (U. 8.) =Spiritus tenuior (Br.), sp. gr. 0.920, used in the preparation of tinctures, contains 53 per cent. It is of about the same strength as the proof spirit of commerce. Analytical Characters.—(1.) Heated with a small quantity of solution of potassium dichromate and S04H„, the liquid assumes an emerald-green color, and if the quantity of C2H60 be not very small, the peculiar fruity odor of aldehyde is developed. (2.) Warmed and treated with a few drops of potash solution and a small quantity of iodine, an alcoholic liquid deposits a yellow, crystalline ppt. of iodoform, either immediately or after a time. (3.) If N03H be added to a liquid containing CaHeO, nitrous ether, recognizable by its odor, is given oft‘. If a solution of mercurous nitrate with excess of NO,H be then added, and the mixture heated, a further evo- lution of nitrous ether occurs, and a yellow-gray deposit of fulminating mercury is formed, which may be collected, washed, dried and exploded. (4.) If an alcoholic liquid be heated for a few moments with S04H2, di- luted with H40 and distilled, the distillate, on treatment with S04H2 and potassium permanganate, and afterward with sodium hyposulphite, yields aldehyde, which may be recognized by the production of a violet color with a dilute solution of fuchsin. None of the above taken singly, is characteristic of alcohol. Action on the Economy.—In a concentrated form, alcohol exerts a de- hydrating action upon animal tissues with which it comes in contact; causing coagulation of the albuminoid constituents. When diluted, ethylic alcohol may be a food, a medicine, or a poison, according to the dose and the condition of the person taking it. When taken in excessive doses, or in large doses for a long time, it produces symptoms and lesions characteristic of pure alcoholism, acute or chronic, modified or 122 MANUAL OF CHEMISTRY. aggravated by those produced by other substances, such as amyl alcohol, which accompany it in the alcoholic fluids used as beverages. Taken in moderate quantities, with food, it aids digestion and produces a sense of comfort and exhilaration. As a medicine it is the most valuable of stimulants. Much has been written concerning the value of alcohol as a food. If it have any value as such, it is as a producer of heat and force by its ox- idation in the body ; experiments have failed to show that more than a small percentage (16 per cent, in 24 hrs.) of medium doses of alcohol in- gested are eliminated by all channels ; the remainder, therefor, disappears in the body, as the idea that it can there “accumulate ” is entirely unten- able. That some part should be eliminated unchanged is to be expected from the rapid diffusion and the high volatility of alcohol. On the other hand, if alcohol be oxidized in the body, we should ex- pect, in the absence of violent muscular exercise, an increase in tempera- ture, and the appearance in the excreta of some product of oxidation of alcohol: aldehyde, acetic acid, carbon dioxide, or water, while the elimi- nation of nitrogenous excreta, urea, etc., would remain unaltered or be diminished. While there is no doubt that excessive doses of alcohol pro- duce a diminution of body temperature, the experimental evidence con- cerning the action in this direction of moderate doses is conflicting and incomplete. Of the products of oxidation, aldehyde has not been detected in the excreta, and acetic acid only in the intestinal canal. The elimi- nation of carbonic acid, as such, does not seem to be increased, although positive information upon this point is wanting. If acetic acid be pro- duced, this would form an acetate, which in turn would be oxidized to a carbonate, and eliminated as such by the urine. The elimination of water under the influence of large doses of alcohol is greater than at other times: but whether this water is produced by the oxidation of the hydrogen of the alcohol, or is removed from the tissues by its dehydrating action, is an open question. While physiological experiment yields only uncertain evidence, the experience of arctic travellers and others shows that the use of alcohol tends to diminish rather than increase the capacity to withstand cold. The experience of athletes and of military commanders is that intense and prolonged muscular exertion can be best performed without the use of alcohol. The experience of most literary men is that long-continued mental activity is more difficult with than without alcohol. In cases of acute poisoning by alcohol, the stomach-pump and catheter should be used as early as possible. A plentiful supply of air, the cold douche, and strong coffee are indicated. Alcoholic Beverages. —The variety of beverages in whose prepara- tion alcoholic fermentation plays an important part is very great, and the products differ from each other materially in their composition and in their physiological action. They may be divided into four classes, the classifi- cation being based upon the sources from which they are obtained and upon the method of their preparation. I. —Those prepared by the fermentation of malted grain—beers, ales, and porters. II. —Those prepared by the fermentation of grape juice—wines. III. —Those prepared by the fermentation of the juices of fruits other than the grape—cider, fruit-ivines. TV.—Those prepared by the distillation of some fermented saccharine liquid—ardent spirits. MONOATOMIC ALCOHOLS. 123 Beer, ale, and porter are aqueous infusions or decoctions of malted grain, fermented and flavored with hops ; they contain, therefor, the soluble con- stituents of the grain employed ; dextrin and glucose, produced during the malting ; alcohol and carbon dioxide, produced during the fermen- tation ; and the soluble constituents of the flavoring material. The al- coholic strength of malt liquors varies from 1.5 to 9 percent. Weiss beer contains 1.5-1.9 per cent.; lager, 41-4.5 per cent. ; bock beer, 3.88- 5.23 per cent. ; London porter, 5.4-G.9 per cent. ; Burton ale, 5.9 per cent. ; Scotch ale, 8.5-9 per cent. Malt liquors all contain a considerable quantity of nitrogenous material (0.4-1 per cent. N), and succinic, lactic, and acetic acids. The amount of inorganic material, in which the phos- phates of potassium, sodium, and magnesium predominate largely, varies from 0.2 to 0.3 per cent. The sp. gr. is from 1.014 to 1.033. The adulterations of malt liquors are numerous and varied. Sodium carbonate is added with the double purpose of neutralizing an excess of acetic acid and increasing the foam. The most serious adulteration consists in the introduction of bitter principles other than hops, and nota- bly of strychnine, cocculus indicus (picrotoxin), and picric acid. Wines are produced by the fermentation of grape-juice : in the case of red wines the marc, or mass of skins, seed and stems, is allowed to remain in contact with the must, or fermenting juice, until, by production of al- cohol, the liquid dissolves a portion of the coloring-matter of the skins. A certain proportion of tannin is also dissolved, whose presence is neces- sary to prevent stringiness. Sweet wines are produced from must rich in glucose and by arresting the fermentation before that sugar has been com- pletely decomposed. Dry wines are obtained by more complete fermen- tation of must less rich in glucose. Tartaric acid is the predominating acid in grape-juice, and as the proportion of alcohol increases during fer- mentation the acid potassium tartrate is deposited. Most wines of good quality improve in flavor with age, and this im- provement is greatly hastened by the process of pasteuring, which con- sists in warming the wine to a temperature of 60° C. (140° F.), without contact of air. Light wines are those whose percentage of alcohol is less than 12 per cent. In this class are included the clarets, Sauternes, Rhine, and Moselle wines ; champagnes, Burgundies, the American wines (except some varie- ties of California wine) Australian, Greek, Hungarian, and Italian wines. The champagnes and some Moselle wines are sparkling, a quality which is communicated to them by bottling them before the fermentation is completed, thus retaining the carbon dioxide, which is dissolved by virtue of the pressure which it exerts. When properly prepared they are agreeable to the palate, and assist the digestion ; when new, however, they are liable to communicate their fermentation to the contents of the stomach and thus seriously disturb digestion. Of the still wines, the most widely used are the clarets, Vinum ruorum (U. S.), or red Bordeaux wines, and the hocks, Vinum album (U. S.), or white Rhine, Moselle and American wines. The former are of low alcoholic strength, mildly astringent, and contain but a small quantity of nitrogen- ous material, qualities which render them particularly adapted to table use and as mild stimulants. The Rhine wines are thinner and more acid, and generally of lower alcoholic strength than the clarets. The Burgundy and Rhone wines are celebrated for their high flavor and body ; they are not strongly alcoholic, but contain , a large quantity of nitrogenous ma- terial, to which they are indebted for their notoriety as developers of 124 MANUAL OF CHEMISTRY. gout. Our native American wines, particularly those of the Ohio Valley and of California, are yearly improving in flavor and quality ; they more closely resemble the Bhine wines and Sauternes than other European wines. Heavy wines are those whose alcoholic strength is greater than 12 per cent., usually 14 to 17 percent.; they include the sherries, ports, Madeiras, Marsala, and some California wines, and are all the products of warm climates. Sherry is an amber-colored wine, grown in the south of Spain, Vinum Xericum (Br.). Marsala closely resembles sherry in appearance, and is frequently substituted for it. Port is a rich, dark red wine, grown in Portugal. The adulteration of wine by the addition of foreign substances is confined almost entirely to their artificial coloration, which is produced by the most various substances, indigo, logwood, fuchsine, etc. The addi- tion of natural constituents of wines, obtained from other sources, and the mixing of different grades of wine are, however, extensively practised. Water and alcohol are the chief substances so added ; an excess of the former may be detected by the taste, and the low sp. gr. after expulsion of the alcohol. Most wines intended for export are fortified by the addition of alcohol; when the alcoholic spirit used is free from amyl alcohol, and is added in moderate quantities, there can be no serious objection to the practice, especially when applied to certain wines which, without such treatment, do not bear transportation. The mixing of fine grades of wine with those of a poorer quality is extensively practised, particularly with champagnes, clarets, and Burgundies, and is perfectly legitimate. The same cannot be said, however, of the manufacture of factitious wine, either entirely from materials not produced from the grape, or by con- converting white into red wines, or by mixing wines with coloring matters, alcohol, etc., to produce imitations of wines of a different class, an indus- try which flourishes extensively in Normandy, at Bingen on the Bhine, and at Hamburg. The wines so produced are usually heavy wines, port and sherry so-called. Cider is the fermented juice of the apple, prepared very much in the same way as wine is from grape-juice, and containing 3.5 to 7.5 per cent, of alcohol. It is very prone to acetous fermentation, which renders it sour and not only unpalatable, but liable to produce colic and diarrhoea with those not hardened to its use. Spirits are alcoholic beverages, prepared by fermentation and distilla- tion. They differ from beers and wines in containing a greater propor- tion of alcohol, and in not containing any of the non-volatile constituents of the grains or fruits from which they are prepared. Besides alcohol and water they contain acetic, butyric, valerianic and cenanthic ethers, to which they owe their flavor ; sometimes tannin and coloring matter derived from the cask ; amylic alcohol remaining after imperfect purifica- tion ; sugar intentionally added ; and Caramel. It is to the last-named sub- stance that all dark spirits owe their color ; although, after long keeping in wood a naturally colorless spirit assumes a straw color. The varieties of spirituous beverages in common use are : Brandy, spiritus vini gallici (U. S., Br.), obtained by the distillation of wine, and manufactured in France and in California and Ohio. It is of sp. gr. 0.929 to 0.934, is dark or light in color, according to the quantity of burnt sugar added, and contains about 1.2 per cent, of solid matter. American whiskey, spiritus frumenti (U. S.), prepared from wheat, rye, barley, or Indian corn; has a sp. gr. of 0.922 to 0.937 and contains 0.1 to MONO ATOMIC ALCOHOLS. 125 0.3 per cent, of solids. Scotch and Irish whiskies, colorless spirits distilled from fermented grains: sp. gr. 0.915 to 0.920, having a peculiar smoky flavor produced by drying the malted grain by a peat fire. Gin, also dis- tilled from malted grain, sp. gr. 0.930 to 0.944, flavored with juniper, and sometimes fraudulently with turpentine. Rum, a spirit distilled from molasses, and varying in color and flavor from the dark Jamacia rum to the colorless St. Croix rum. The former is of sp. gr. 0.914 to 0.926, and con- tains one per cent, of solid matter. Liqueurs are spirits sweetened and flavored with vegetable aromatics, and frequently colored ; anisette is flavored with aniseed; absinthe, with wormwood ; curagoa, with orange-peel; kirschwasser, with cherries, the stones being cracked and the spirits distilled from the bruised fermented fruit; kiimmel, with cummin and caraway seeds ; maraschino, with cherries ; noyeau, with peach and apricot kernels. Propyl hydrate—Ethyl carbinol—Primary propyl alcohol—C3H7OH —60—is produced, along with ethylic alcohol, during fermentation, and obtained by fractional distillation of marc brandy, from cognac oil, huile de marc (not to be confounded with oil of wine), an oily matter, possessing the flavor of inferior brandy, which separates from marc brandy, distilled at high temperatures; and from the residues of manufacture of alcohol from beet-root, grain, molasses, etc. It is a colorless liquid, has a hot alcoholic taste, and a fruity odor ; boils at 96.7° (206°.1 F.) ; and is mis- cible with water. It has not been put to any use in the arts. Its intoxi- cating and poisonous actions are greater than those of ethyl alcohol. It exists in small quantity in cider. Butyl alcohols—C4H9OH—74.—Of the four butyl alcohols theoret- ically possible three are known to exist: Primary normal butyl alcohol—Butyl alcohol of fermentation—Propyl carbinol—CH3—CH2—CII2—CH..OH—is formed in small quantities during alcoholic fermentation, and may be obtained by repeated fractional dis- tillation from the oily liquid left in the rectification of vinic alcohol. It is a colorless liquid ; boils at 114°.7 (238°.5 F.). It is more actively poi- sonous than ethyl or methyl alcohol. Secondary butyl alcohol; ethyl-methyl carbinol—CH—CII \ ~rTr.TT CH3/UilUil_“ a liquid which boils at 99° (210°.2 F.). CH3\ Tertiary butyl alcohol; trimethyl carbinol, CH3—COH—a crystalline CH3/ solid, which fuses at 20°-25° (68°-77° F.), and boils at 82° (179°.6 F.). Amylie alcohols—C5H,OH—88.—Of the eight amyl alcohols theo- retically possible (see p. 118) seven have been obtained. The substance usually known as amylie alcohol, potato spirit, fusel oil, alcohol amylicum (Br.), is a mixture in varying proportions of the two primary alcohols ; CH — CH..0H and CH’~^£5^CH—CHaOH ; the former dif- .3' ... / fering from the latter in that it deviates the plane of polarization to the left ([a]D = —4°.36') ; in its boiling-point being 2° (3°.6 F.) lower, and in the greater solubility of the amyl-sulphate of barium obtained from it. It is formed during alcoholic fermentation of glucose in greater abun- dance than any of the alcohols other than the ethylic. Owing to its high boiling-point, it is in great part retained in the oily material which collects in the still during the rectification of alcohol and spirits ; a portion, how- ever, passes over and is removed by subsequent treatment (see below). It 126 MANUAL OF CHEMISTRY. is obtained from the last milky products of rectification of alcoholic fluids made from grain or potatoes ; these are shaken with H20 to remove ethyl alcohol, the supernatant oily fluid is decanted, dried by contact with fused calcium chloride, and distilled ; that portion which passes over between 128° and 132° (262°.4-269°.6 F.) being collected. It is a colorless, oily liquid, has an acrid taste and a peculiar odor, at first not unpleasant, afterward nauseating and provocative of severe head- ache ; it boils at 132° (2G9°.6 F.) and crystallizes at —20° (4° F.) ; sp. gr. 0.8184 at 15° (5° F.) ; it mixes with alcohol and ether, but not with water. It burns difficultly with a pale blue flame. When exposed to air it oxidizes very slowly ; quite rapidly, however, in contact with platinum-black, forming valerianic acid. The same acid, along with other substances, is produced by the action of the more power- ful oxidants upon amyl alcohol. Chlorine attacks it energetically, forming amyl chloride, HC1, and other chlorinated derivatives. Sulphuric acid dissolves in amyl alcohol, with formation of amyl-sulphuric acid, S04 (0,11,,)H, corresponding to ethyl-sulphuric acid. It also forms similar acids with phosphoric, oxalic, citric, and tartaric acids. Its ethers, when dissolved in ethyl alcohol, have the taste and odor of various fruits, and are used in the preparation of artificial fruit-essences. Amyl alcohol is also used in analysis as a solvent, particularly for certain alkaloids, and in phar- macy for the artificial production of valerianic acid and the valerianates. Its vapor, when inhaled, produces severe headache, a sense of suffo- cation, giddiness, and, in large doses, death. The liquid, taken internally, especially when in alcoholic solution, is much more actively poisonous than etliylic alcohol. Even in very dilute solution it produces the rapid intoxication, and severe headache and vertigo, which are prominent effects of inferior whiskey. To free spirits of amyl alcohol, to defuselate them, advantage is usually taken of the absorbent power of freshly burnt wood charcoal, which is either placed in the still or made into a filter, through which the spirit is passed after distilliation, or, preferably, the vapor from the still is made to pass through a layer of charcoal before condensation. Spirits properly freed of fusel oil give off no irritating or foul fumes, when hot; they are not colored red when mixed with three parts C,,HeO and one part strong S04H2 ; they are not colored red or black by ammoniacal silver nitrate solution ; when 150 parts of the spirit mixed with 1 part potash, dis- solved in a little H„0, are evaporated down to 15 parts, and mixed with an equal volume of dilute S04H„, no offensive odor should be given off. Cetyl hydrate—Cetylic alcohol—Ethal—C)6H3SOH—242—is obtained by the saponification of spermaceti (its palmitic ether). It is a white crys- talline solid; fusible at 49° (120°.2 F.) ; insoluble in H20 ; soluble in alcohol and ether ; tasteless and odorless. Ceryl hydrate—C27H66OH—396—and Myricyl hydrate—CS„H6] OH—438—are obtained as white, crystalline solids: the former from China wax ; the latter from beeswax, by saponification. SIMPLE ETHERS. Oxides of Alcoholic Radicals of the Series CnH„n+1. The term ether was originally applied to anj* volatile liquid obtained by the action of an acid upon an alcohol. The simple ethers are the oxides of the alcoholic radicals. They bear the SIMPLE ETHERS. 127 same relation to the alcohols that the oxides of the basylous elements bear to their hydrates: C,H, | C5H, f u !}o c£}° g}0 Ethyl oxide (ethylic ether). Potassium oxide. Ethyl hydrate (alcohol.) Potassium hydrate. When the two alcoholic radicals are the same, as in the above instance, the ether is designated as simple ; when the radicals are different, as in CH ) methyl-ethyl oxide, q pj3 r O, they are called mixed ethers. 2 no ■) Methyl oxide —- O—4G—isomeric with ethyl alcohol, is ob- tained by the action of S04H2 and boric acid upon methyl alcohol, or by the action of silver oxide on methyl iodide. It is a colorless gas; has an ethereal odor ; burns with a pale flame ; liquefies at —36° ( —32°.8 F.); and boils at — 21°(—5°.8 F.) ; is soluble in H20, S04H2 and ethyl alcohol. Ethyl oxide—Ethylic ether—Ether—Sulphuric ether—JEther fortior (U. S.)—jEther purus (Br.)—| O—74. Preparation.—A mixture is made of 5 pts. of alcohol, 90 vered vats, from which the vinegar is drawn off after acetification has 3en completed ; the mother is collected, washed, and used in a subsequent peration. The liquids from which vinegar is made are wine, cider, and beer, to hich dilute alcohol is frequently added ; the most esteemed being that stained from white wine. Wine vinegar has a pleasant, acid taste and lor ; it consists of water, acetic acid (about 5 per cent.), potassium bitar- ate, alcohol, acetic ether, glucose, malic acid, mineral salts present in ine, a fermentescible, nitrogenized substance, coloring matter, etc. Sp. 132 MANUAL OF CHEMISTRY. gr. 1.020 to 1.025. When evaporated, it yields from 1.7 to 2.4 per cent, of solid residue. Vinegars made from alcoholic liquids other than wine contain no po- tassium bitartrate, contain less acetic acid, and have not the aromatic odor of wine vinegar. Cider vinegar is of sp. gr. 2.0 ; is yellowish, has an odor of apples, and yields 1.5 per cent, of extract on evaporation. Beer vinegar is of sp. gr. 3.2 ; has a bitterish flavor, and an odor of sour beer ; it leaves 6 per cent, of extract on evaporation. The principal adulterations of vinegar are : sulphuric acid, which pro- duces a black or brown color when a few drops of the vinegar and some fragments of cane-sugar are evaporated over the water-bath to dryness. Water, an excess of which is indicated by a low power of saturation of the vinegar, in the absence of mineral acids. Two parts of good wine vinegar neutralize 10 parts of sodium carbonate ; the same quantity of cider vine- gar, 3.5 parts ; and of beer vinegar, 2.5 parts of carbonate. Pyroligneous acid may be detected by the creosote-like odor and taste. Pepper, capsi- cum, and other acrid substances, are often added to communicate fictitious strength. In vinegar so adulterated an acrid odor is perceptible after neutralization of the acid with sodium carbonate. Copper, zinc, lead, and tin frequently occur in vinegar which has been in contact with those ele- ments, either during the process of manufacture or subsequently. Distilled vinegar is prepared by distilling vinegar in glass vessels ; it contains none of the fixed ingredients of vinegar, but its volatile constitu- ents (acetic acid, water, alcohol, acetic ether, odorous principles, etc.), and a small quantity of aldehyde. When dry acetate of copper is distilled, a blue, strongly acid liquid passes over ; this, upon rectification, yields a colorless, mobile liquid, which boils at 56° (132°.8 F.), has a peculiar odor, and is a mixture of acetic acid, water, and acetone, known as radical vinegar. Toxicology.—When taken internally, acetic acid and vinegar (the latter in doses of 4-5 fl. § ) act as irritants and corrosives, causing in some in- stances perforation of the stomach, and death in 6-15 hours. Milk of magnesia should be given as an antidote, with the view to neutralizing the acid. Propionic acid—C2H5CO,OH —74—is formed in many decomposi- tions of organic substances : By the action of caustic potassa upon sugar, starch, gum, and ethyl cyanide ; during fermentation, vinous or acetic ; in the distillation of wood ; during the putrefaction of peas, beans, etc. ; by the oxidation of normal propylic alcohol, etc. It is best prepared by heating ethyl cyanide with potash until the odor of the ether has disap- peared ; the acid is then liberated from its potassium compound by S04H3 and purified. It is a colorless liquid, sp. gr. 0.996, does not solidify at —21° (—5°.8 F.), boils at 140° (284° F.), mixes with water and alcohol in all proportions, resembles acetic acid in odor and taste. Its salts are soluble and crys- tallizable. Butyric acid—CsH7CO,OH—88—has been found in the milk, per- spiration, muscular fluid, the juices of the spleen and of other glands, the urine, contents of the stomach and large intestine, feces, and guano ; in certain fruits, in yeast, in the products of decomposition of many vege- table substances ; and in natural waters ; in fresh butter in small quantity, more abundantly in that which is rancid. It is formed by the action of S04Ha and manganese dioxide, aided by heat, upon cheese, starch, gelatin, etc. ; during the combustion of tobacco MONOBASIC ACIDS. 133 (as ammonium butyrate) ; by the action of N03H upon oleic acid ; during the putrefaction of fibrin and other albuminoids ; during a peculiar fer- mentation of glucose and starchy material in the presence of casein or gluten. This fermentation, known as the butyric, takes place in two stages ; at first the glucose is converted into lactic acid: C6H1206 = 2(C3H603) ; and this in turn is decomposed into butyric acid, carbon di- oxide, and hydrogen : 2C3H603 = C4H802 + 2C02 + 2H2. Butyric acid is obtained from the animal charcoal which has been used in the purification of glycerin, in which it exists as calcium butyrate. It is also formed by subjecting to fermentation a mixture composed of glu- cose, water, chalk, and cheese or gluten. The calcium butyrate is de- composed by S04H2, and the butyric acid separated by distillation. Butyric acid is a colorless, mobile liquid, having a disagreeable, per- sistent odor of rancid butter, and a sharp, acid taste ; soluble in water, alcohol, ether, and methyl alcohol; boils at 164° (327°.2 F.), distilling unchanged ; solidifies in a mixture of solid carbon dioxide and ether ; sp. gr. 0.974 at 15° (59° F.) ; a good solvent of fats. It is not acted upon by S04H2 in the cold, and only slightly under the influence of heat. Nitric acid dissolves it unaltered in the cold, but on the application of heat, oxidizes it to succinic acid. Dry Cl under the influence of sunlight, and Br under the influence of heat and pressure, form pro- ducts of substitution with butyric acid. It readily forms ethers and salts. Butyric acid is formed in the intestine, by the process of fermentation mentioned above, at the expense of those portions of the carbohydrate elements of food which escape absorption, and is discharged with the faeces as ammonium butyrate. Isobutyric acid, an isomere of butyric acid, which boils at 152° (305°.6 F.), has also been found in human faeces. It corresponds to isobutyl alcohol. Valerianic acids—C4H0CO,OH—102.—Corresponding to the four primary amylic alcohols, there are four amylic or valerianic acids : I. CH — CH — CH — CH — CO,OH. H. j^^CH—CH — CO,OH. CH\ CH3\ HI. ptr n33 / CH—CO,OH. IV. CH3—C—CO,OH. CH3-CH3/ CH / I. Normal valerianic acid—Butylformic acid—Propylacetic acid— is obtained by the oxidation of normal amylic alcohol. It is an oily liquid, boils at 185° (365° F.), and has an odor resembling that of butyric acid. II. III. Ordinary valerianic acid—Delphinic acid—Phocenic acid— Isovaleric acid—Isopropyl acetic acid—Isobutylformic acid—Acidum valeri- anicum (Br.).—This acid exists in the oil of the porpoise, and in valerian root and in angelica root. It is formed during putrid fermentation or oxidation of albuminoid substances. It occurs in the urine and faeces in typhus, variola, and acute atrophy of the liver. It is also formed in a variety of chemical reactions and notably by the oxidation of amylic alcohol. It is prepared either by distilling water from valerian root, or, more economically, by mixing rectified amylic alcohol with S04H2, adding when cold, a solution of potassium dichromate, and distilling after the reaction has become moderated : the distillate is neutralized with sodium carbon- ate ; and the acid is obtained from the sodium valerianate so produced, by decomposition by SO.H2 and rectification. 134 MANUAL OF CHEMISTRY. The properties and nature of the acid differ according to those of the amyl alcohol from which it is obtained. The active alcohol yields the acid, 0jj3^/CH—CHa—CO, OH, which is itself optically active ; which forms an uncrystallizable and exceedingly soluble barium salt, and whose boiling- point is 173°.5 (344°.3 F.). The inactive alcohol yields by oxidation the CH \ acid, (jy3^/CH—CO, OH, which is optically inactive ; whose barium salt is readily crystallizable and soluble in water to the extent of 48 parts in 100 ; and whose boiling-point is 174°.5 (346° F.). The acid obtained from valerian root is identical with the acid obtained by the oxidation of optically inactive amylic alcohol. The artificial product, being obtained from the commercial mixture of active and inactive alcohols, is a mixture in different proportions of the two acids mentioned above. The ordinary valerianic acid is an oily, colorless liquid, having a pene- trating odor, and a sharp, acrid taste. It solidifies at —16° (3°.2 F.); boils at 173°-175° (343°.4-347° F.); sp. gr. 0.9343-0.9465 at 20° (68° F.); burns with a white, smoky flame. It dissolves in 30 parts of water, and in alcohol and ether in all proportions. It dissolves phosphorus, camphor, and certain resins. IY. Trimethyl acetic acid—Pivalic acid—is a crystalline solid, which fuses at 35.5° (96° F.) and boils at 163°.7 (326°.7 F.) ; sparingly soluble in H20 ; obtained by the action of cyanide of mercury upon tertiary butyl iodide. Caproic acids—Hexylic acids—C5HnCO,OH—116.—There probably exist quite a number of isomeres having the composition indicated above, some of which have been prepared from butter, cocoa-oil, and cheese, and by decomposition of amyl cyanide, or of hexyl alcohol. The acid obtained from butter, in which it exists as a glyceric ether, is a colorless, oily liquid, boils at 205° (401° F.); sp. gr. 0.931 at 15° (59° F.); has an odor of perspiration and a sharp, acid taste ; is very sparingly soluble in water, but soluble in alcohol. (Enanthylic acid — Ileptylic acid — C6H13CO,OH—130—exists in spirits distilled from rice and maize, and is formed by the action of N03H on fatty substances, especially castor oil. It is a colorless oil; sp. gr. 0.9167 ; boils at 212° (413°.6 F.). Caprylic acid — Octylic acid — C.Hj rCO,OH —144 — accompanies caproic acid in butter, cocoa-oil, etc. It is a solid ; fuses at 15° (59° F.); boils at 236° (457° F.); almost insoluble in HaO. Pelargonic acid—Nonylic acid—ChH]7CO,OH—158.—A colorless oil, solid below 10° (50° F.); boils at 260° (500° F.); exists in oil of geranium, and is formed by the action of NOaH on oil of rue. Capric acid — Decylic acid—C9H13CO,OH—172—exists in butter, cocoa-oil, etc., associated with caproic and caprylic acids in their glyceric ethers, and in the residues of distillation of Scotch whiskey, as amyl caprate. It is a white, crystalline solid ; melts at 27°.5 (81°.5 F.); boils at 273° (523°.4 F.). Laurie acid — Laurostearic add—CnH .CO,OH—200—is a solid, fusible at 43°.5 (110°.3 F.) obtained from laurel berries, cocoa-butter, and other vegetable fats. Myristic acid—C13H.,7CO,OH—228.—A crystalline solid, fusible at 54° (129°.2 F.); existing in many vegetable oils, cow’s butter, and spermaceti. Palmitic acid—Ethalic add—Clf>H31CO,OH—256—exists in palm-oil, in combination when the oil is fresh, and free when the oil is old ; it also COMPOUND ETHERS. 135 enters into the composition of nearly all animal and vegetable fats. It is obtained from the fats, palm-oil, etc., by saponification with caustic potassa and subsequent decomposition of the soap by a strong acid. It is also formed by the action of caustic potash in fusion upon cetyl alcohol (ethal), and by the action of the same reagent upon oleic acid. Palmitic acid is a white, crystalline solid ; odorless ; tasteless ; lighter than H20, in which it is insoluble ; quite soluble in alcohol and in ether; fuses at 62° (143°. 6 F.); distils unchanged with vapor of water. Margaric acid—C17H33CO,OH—2 70—formerly supposed to exist as a glyceride in all fats, solid and liquid. What had been taken for margaric acid was a mixture of 90 per cent, of palmitic and 10 per cent, of stearic acid. It is obtained by the action of potassium hydrate upon cetyl cyanide, as a white, crystalline body ; fusible at 59°. 9 (140° F.). Stearic acid—C17H36CO,OH—284—exists as a glyceride in all solid fats, and in many oils, and also free to a limited extent. To obtain it pure, the fat is saponified with an alkali, and the soap decomposed by HC1; the mixture of fatty acids is dissolved in a large quantity of alcohol, and the boiling solution partly precipitated by the addition of a concentrated solution of barium acetate. The precipitate is collected, washed, and decomposed by HC1; the stearic acid which sepa- rates is washed and recrystallized from alcohol. The process is repeated until the product fuses at 70° (158° F.). Pure stearic acid is a colorless, odorless, tasteless solid ; fusible at 70° (158° F.); unctuous to the touch; insoluble in H20 ; very soluble in alcohol and in ether. The alkaline stearates are soluble in H20 ; those of Ca, Ba, and Pb are insoluble. Stearic and palmitic acids exist free in the intestine during the diges- tion of fats, a portion of which is decomposed by the action of the pan- creatic secretion into fatty acids and glycerin. The same decomposition also occurs in the presence of putrefying albuminoid substances. Arachio acid—C,9H39CO,OH—312—exists as a glyceride in peanut- oil (now largely used as a substitute for olive-oil), in oil of ben, and in small quantity in butter. It is a crystalline solid, which melts at 75° (167° F.). COMPOUND ETHERS. As the alcohols resemble the mineral bases, and the organic acids re- semble those of mineral origin, so the compound ethers are similar in con- stitution to the salts, being formed by the double decomposition of an alcohol with an acid, mineral or organic, as a salt is formed by double decomposi- tion of an acid and a mineral base, the radical playing the part of an atom of corresponding valence. h}° + = + <*$\o Totassium hydrate. t Nitric acid. Water. Potassium nitrate. (C,HHIo - (NOil}o = i}0 + «®}o Ethyl hydrate (alcohol). Nitric acid. Water. Ethyl nitrate (nitric ether). 136 MANUAL OF CHEMISTRY. Methyl nitrate—j- O—77.—A colorless liquid ; sp. gr. 1.182 at 22° (71°.6 F.) ; boils at 66° (150°.8 F.) ; gives off vapor which detonates at 150° (302° F.). Prepared by the action of potassium nitrate and S04 H2 on methyl alcohol. Methyl nitrite—| O—61—obtained by heating methyl alcohol with NOsH andCu. Below —12° (10°.4 F.) it is a yellowish liquid ; above that temperature a gas. Ethyl nitrate—Nitric ether J l O—91.—A colorless liquid ; has a sweet taste and bitter after-taste ; sp. gr. 1.112 at 17 (62 .6 F.) ; boils at 85° (185° F.) ; gives off explosive vapors. Prepared by distilling a mix- ture of N03H and C2H60 in the presence of urea. Ethyl nitrite—Nitrous ether—(Jjj* j- O—75—is best prepared by directing the nitrous fumes, produced by the action of starch on N03H under the influence of heat, into alcohol, contained in a retort connected with a well-cooled receiver. It is a yellowish liquid ; has an apple-like odor, and a sharp, sweetish taste ; sp. gr. 0.947 ; boils at 18° (64°.4 F.) ; gives off inflammable vapor ; very sparingly soluble in H20 ; readily soluble in alcohol and ether. Warm H20 decomposes it into ; NOsH and NO. Alkalies de- compose it into malate and nitrate of the alkaline element. It is ener- getically attacked by S04H„, H2S and the alkaline sulphides. It is liable to spontaneous decomposition, especially in the presence of H20, into NO and malic acid. Its vapor rapidly produces anaesthesia ; it is, however, used only in alco- holic solution: Spiritus cetheris nitrosi (U. S., Br.), which also contains aldehyde. Owing to the presence of the last-named substance, and to the presence of H20, the spirit is very liable to become acid, either from the formation of acetic acid by the oxidation of the aldehyde, or from the decomposition of the ether under the influence of H„0, a change which renders it unfit for use in many of the prescriptions in which it is fre- quently used, especially in that with potassium iodide, from which it liber- ates iodine. The presence of free acid may be detected by effervescence when the spirit is shaken with hydrosodic carbonate. Its acidity may be corrected by shaking with potassium carbonate, and decanting, provided it does not contain H20. Ethyl sulphates.—These are two in number: S04(C2Hr)H—Ethyl-sul- phuric, or sulphovinic acid ; S04(C2Hr)2—Ethyl-sulphate—Sulphuric ether. soj Ethyl-Sulphuric Acid—(C2Hs) v 02—126—is formed as an interme- S) diate product in the manufacture of ethylic ether (q. v.). Pure ethyl-sulphuric acid is a colorless, syrupy, highly acid liquid ; sp. gr. 1.316 ; soluble in water and alcohol in all proportions, insoluble in ether. It decomposes slowly at ordinary temperatures, more rapidly when heated. When heated alone or with alcohol, it yields ether and S04H2. When heated with H,0, it yields alcohol and S04H2. It forms crystalline salts, known as sulphovinates, one of which, sodium sulphovinaie, S04 (C2H5)Na, has been used in medicine. It is a white, deliquescent solid, COMPOUND ETHEKS. 137 either crystalline with lAq., or granular and anhydrous ; soluble in H,,0. Its solution should give no precipitate with barium chloride. Ethyl Sulphate j- Oa—154—the true sulphuric ether, is ob- tained by passing vapor of S03 into pure ethylic ether, thoroughly cooled. It is a colorless, oily liquid ; has a sharp, burning taste, and the odor of peppermint; sp. gr. 1.120; it cannot be distilled without decompo- sition ; in contact with HaO it is decomposed with formation of sulpho- vinic acid. By the action of an excess of S04H9 upon alcohol; by the dry distil- lation of the sulphovinates ; and in the last stages of manufacture of ether, a yellowish, oily liquid, having a penetrating odor and a sharp, bitter taste, is formed ; this is sweet or heavy oil of wine, and its ethereal solution is Oleum cethereum (U. S.). It seems to be a mixture of ethyl-sulphate with hydro- carbons of the series CnH2n. On contact with H,,0 or an alkaline solution, it is decomposed, sulphovinic acid is formed, and there separates a color- less oil, of sp. gr. 0.917, boiling at 280° (536° F.), which is light oil of wine. This oil is polymeric with ethylene, and is probably cetene, CICH3a; it is sometimes called etherine or etherol. Q IT A ] Ethyl acetate—Acetic ether—JEther aceticus (U. S.)— - O— 88—is obtained by distilling a mixture of sodium acetate, alcohol and S04H2; or by passing carbon dioxide through an alcoholic solution of potassium acetate. • It is a colorless liquid, has an agreeable, ethereal odor; boils at 74° (165°.2 F.) ; sp. gr. 0.89 at 15° (59° F.) ; soluble in 6 pts. water, and in all proportions in methyl and ethyl alcohols and in ether; a good solvent of essences, resins, cantharidine, morphine, gun-cotton, and, in general, of substances soluble in ether ; burns with a yellowish white flame. Chlor- ine acts energetically upon it, producing products of substitution, varying according to the intensity of the light from C4H6ClaOa to C4Cl8Oa. Amyl nitrate— j O —133—obtained by distilling a mixture of . 11 ' N03H and amylic alcohol in the presence of a small quantity of urea. It is a colorless, oily liquid ; sp. gr. 0.994 at 10° (50° F.) ; boils at 148° (298°.4 F.) with partial decomposition. Amyl nitrite—Amyl nitris (U. S.)—| O—117—prepared by directing the nitrous fumes, evolved by the action of NO;iH upon starch, into amyl alcohol contained in a retort heated over a water-bath ; purifying the distillate by washing wTith an alkaline solution ; and rectifying. It is a slightly yellowish liquid ; sp. gr. 0.877 ; boils at 95° (203° F.) ; its vapor explodes when heated to 260° (500° F.) ; insoluble in water; soluble in alcohol in all proportions; vapor orange-colored. Alcoholic solution of potash decomposes it slowly, with formation of potassium ni- trite and oxides of ethyl and amyl. When dropped upon fused potash, it ignites and yields potassium valerianate. Amyl nitrite is frequently impure ; its boiling-point should not vary more than two or three degrees from that given above. Cetyl palmitate—Cetine—| O—480—is the chief constit- uent of spermaceti — cetaceum (U. S., Br.). This is the concrete portion, obtained by expression and crystallization from alcohol, of the oil con- tained in the cranial sinuses of the sperm-whale. It forms white, crystal- 138 MANUAL OF CHEMISTRY. line plates ; fusible at 49° (120°.2 F.) ; slightly unctuous to the touch ; tasteless, and almost odorless ; insoluble in water ; soluble in alcohol and ether ; burns with a bright flame. Besides cetine, it contains ethers not only of palmitic, but also of stearic, myristic, and laurostearic acids ; and of the alcohols : lethal, C12H260 ; methal, C14H30O ; ethal, C16H340 ; and stethal, C18H380. C H O ) Melissyl palmitate — Melissin— q jj \ O—676.—Beeswax con- sists mainly of two substances ; cerotic acid, C27HB30,0H, which is soluble in boiling alcohol, and melissyl palmitate, insoluble in that liquid, united with minute quantities of substances which communicate to the wax its color and odor. Yellow wax melts at 62°-63° (143°.6-145°.4 F.) ; after bleach- ing, which is brought about by exposure to light, air, and moisture, it does not fuse below 66° (150°.8 F.). China wax, a white substance resembling spermaceti, is a vegetable product, consisting chiefly of ceryl cerotate, C27H6302(C27HJ. ALDEHYDES. Series CnH3„0. Formic aldehyde CH20. Acetic al(jehyde C2H40. l’ropionic aldehyde C3H60. Butyric aldehyde C4HgO. Isobutyrlc aldehyde C4H80. Valerianic aldehyde ,C5H10O. Caproic aldehyde C6H120. CEnanthylic aldehyde C7H140. Caprylic aldehyde C8HleO. Palmitic aldehyde C16H320. It will be remembered that the monobasic acids are obtained from the alcohols by oxidation of the radical: «^}0 (CAoyjo Ethyl alcohol. Acetic acid. These oxidized radicals are capable of forming compounds similar in con- stitution to those of the non-oxidized radicals. There are chlorides, bro- mides, and iodides; their hydrates are the acids, j O = acetic ,n jj q\ i * acid ; their oxides are known as anhydrides, (CAO) f O = acetic anhy- dride ; and their hydrides are the aldehydes j. _ acetic aldehyde. The name aldehyde is a corruption of alcohol dehydrogenatum, from the method of their formation, by the removal of hydrogen from alcohol. The aldehydes all contain the group of atoms (COH)', and their con- stitution may be thus graphically indicated: COH I CH, I CH, COH I ch3 Acetic aldehyde. Propionic aldehyde. ALDEHYDES. 139 They are capable, by fixing H2, of regenerating the alcohol; and, by fixing O, of forming the corresponding acid : COH I CH, ch2oh CH, CO, OH ch3 Acetic aldehyde. Ethylic alcohol. Acetic acid. C H O ) Acetic aldehyde—Acetyl hydride— 3 3jj j- —44—is formed in all reactions in which alcohol is deprived of H without introduction of O. It is prepared by distilling from a capacious retort, connected with a well-cooled condenser, a mixture of S04H2, 6 pts.; H20, 4 pts.; alcohol, 4 pts. ; and powdered manganese dioxide, 6 pts. The product is redistilled from cal- cium chloride below 50° (122° R). The second distillate is mixed with two volumes of ether, cooled by a freezing mixture, and saturated with dry NH3; there separate crystals of ammonium acetylide, C2HaO, NH4, which are washed with ether, dried, and decomposed in a distilling apparatus, over the water-bath, with the proper quantity of dilute S04H2; the distillate is finally dried over calcium chloride and rectified below 35° (95° R). Aldehyde is a colorless, mobile liquid ; has a strong, suffocating odor ; sp. gr. 0.790 at 18° (64°.4 R) ; boils at 21° (69°.8 R); soluble in all pro- portions in water, alcohol, and ether. If perfectly pure, it may be kept unchanged ; but if an excess of acid have been used in its preparation, it gradually decomposes. When heated to 100° (212° R), it is decomposed into water and crotonic aldehyde. In the presence of nascent H, aldehyde takes up H2 and regenerates alcohol. Cl converts it into acetyl chloride, C2II30, Cl, and other products. Oxidizing agents quickly convert it into acetic acid. At the ordinary tem- perature S04H2; HC1; and S02 convert it into a solid substance called paraldehyde, C6H1203 (?), which fuses at 10.5° (50°.9 R); boils at 124° (255°.2 F.), and is more soluble in cold than in warm water. When heated with potassium hydrate, aldehyde becomes brown, a brown resin separates, and the solution contains potassium formiate and acetate. If a watery solution of aldehyde be treated, first with NH3 and then with II2S, a solid, crystalline base, thialdine, C6II13NS„, separates. It also forms crystalline compounds with the alkaline bisulphites. It decomposes solutions of silver nitrate, separating the silver in the metallic form, and under condi- tions which cause it to adhere strongly to glass. Yapor of aldehyde, when inhaled in a concentrated form, produces as- phyxia, even in comparatively small quantity ; when diluted with air it is said to act as an anaesthetic. When taken internally it causes sudden and deep intoxication, and it is to its presence that the first products of the distillation of spirits of inferior quality owe in a great measure their rapid, deleterious action. C Cl O 1 Trichloraldehyde—Trichloracetyl hydride—Chloral— 3 3jj j-— 147.5—is one of the final products of the action of Cl upon alcohol, and is obtained by passing dry Cl through absolute alcohol to saturation ; apply- ing heat toward the end of the reaction, which requires several hours for its completion. The liquid separates into two layers ; the lower is removed and shaken with an equal volume of concentrated SO„H2 and again allowed to separate into two layers ; the upper is decanted ; again mixed with S04H2, from which it is distilled ; the distillate is treated with quicklime, 140 MANUAL OF CHEMISTRY. from which it is again distilled, that portion which passes over between 94° and 99° (201°.2-210°. 2 F.) being collected. It sometimes happens that chloral in contact with SO„H2 is converted into a modification, insoluble in II20, known as metachloral; when this occurs it is washed with 1I20, dried and heated to 180° (356° F.), when it is converted into the soluble variety, which distils over. Chloral is a colorless liquid, unctuous to the touch ; has a penetrating odor and an acrid, caustic taste ; sp. gr. 1.502 at 18° (64°.4 F.) ; boils at 94.4° (201°.9 F.) ; very soluble in water, alcohol, and ether ; dissolves Cl, Br, I, S and P. Its vapor is highly irritating. It distils without alteration. Although chloral has not been obtained by the direct substitution of Cl for H in aldehyde, its reactions show it to be an aldehyde ; it forms crystalline compounds with the bisulphites ; it reduces solutions of silver nitrate in the presence of NH3; NH„ and II2S form with it a compound similar to thialdine ; with nascent H it regenerates aldehyde ; oxidizing agents convert it into trichloracetic acid. Alkaline solutions decompose it with formation of chloroform and a formiate. With a small quantity of H20 chloral forms a solid, crystalline hydrate, heat being at the same time liberated. This hydrate has the composition C„HC130,H20, and its constitution, as well as that of chloral itself, is indi- cated by the formulae: ch3 I CIIO CC13 I CIIO CC13 I CH(OH)a Aldehyde. Trictaloraldehyde (chloral). Chloral hydrate, Chloral hydrate—Chloral (U. 8.)—is a white, crystalline solid ; fuses at 57° (134°.6 F.); boils at 98° (208°.4 F.), at which temperature it suffers partial decomposition into chloral and H20 ; volatilizes slowly at ordinary temperatures; is very soluble in H20 ; neutral in reaction ; has an ethereal odor, and a sharp, pungent taste. Concentrated S04H2 decomposes it with formation of chloral and chloralide. N03H converts it into trichlor- acetic acid. When pure it gives no precipitate with silver nitrate solution, and is not browned by contact with concentrated S04H2. Chloral also combines with alcohol, with elevation of temperature, to form a solid, crystalline body—chloral alcoholate: CC13—Ch/q^^ Action of Chloral Hydrate upon the Economy.—Although it was the ready decomposition of chloral into a formiate and chloroform which first suggested its use as a hypnotic to Liebreich, and although this decompo- sition was at one time believed to occur in the body under the influence of the alkaline reaction of the blood, more i-ecent investigations have shown that the formation of chloroform from chloral in the blood is, to say the least, highly improbable, and that chloral has, in common with many other chlorinated derivatives of this series, the property of acting directly upon the nerve-centres. Neither the urine nor the expired air contain chloroform wdien chloral is taken internally ; when taken in large doses, chloral appears in the urine. The fact that the action of chloral is prolonged for a longer period than that of the other chlorinated derivatives of the fatty series is probably due, in a great measure, to its less volatility and less rapid elimination. When taken in overdose, chloral acts as a poison, and its use as such KETONES OR ACETONES. 141 is rapidly increasing as acquaintance with its powers becomes more widely disseminated. No chemical antidote is known. The treatment should be directed to the removal of any chloral remaining in the stomach by the stomach-pump, and to the maintenance or restoration of respiration. In fatal cases of poisoning by chloral that substance may be detected in the blood, urine, and contents of the stomach by the following method: the liquid is rendered strongly alkaline with potassium hydrate; placed in a flask, which is warmed to 50°-60° (122°-140° F.), and through which a slow current of air, heated to the same temperature, is made to pass ; the air, after bubbling through the liquid, is tested for chloroform by the methods described on p. 113. If affirmative results are obtained in this testing, it remains to determine whether the chloroform detected existed in the fluid tested in its own form, or resulted from the decomposition of chloral; to this end a fresh portion of the suspected liquid is rendered acid and tested as before. A negative result is obtained in the second testing when chloral is present. C Br O ) Bromal— 2 3jj j- —281.—A colorless, oily, pungent liquid ; sp. gr. 3.34; boils at 172° (341°.6 F.); neutral; soluble in II20, alcohol, and ether. It combines with H20 to form bromal hydrate, CBr3,CH(OIi)2; large transparent crystals ; soluble in II20 ; decomposed by alkalies into bromoform and a formiate. Produces anaesthesia without sleep; very poisonous. KETONES OR ACETONES. Sekies CnH2„0. Although the aldehydes are not acid in reaction, and are not usually regarded as acids, there exist substances known as ketones or acetones, which may be regarded as formed by the substitution of an alcoholic radi- cal for the H of the group COH. These substances all contain the group of atoms (CO)", and their constitution may be represented graphically thus : ch3 I CO I ch2 I ch3 CH3 I CO I OH, Dimethyl ketone (acetone). Methyl-ethyl ketone, the first being a symmetrical ketone and the latter a non-symmetrical. The ketones are isomeric with the aldehydes, from which they are distinguished: 1st, by the action of H, which produces a primary alcohol with an alde- hyde, and a secondary alcohol with a ketone : COH CH2OII CH2 + H, = CH, I I ch3 ch3 Propionic aldehyde. Propyl alcohol. 142 MANUAL OF CHEMISTRY. CH3 , ch3 I I CO + H3 = CH,OH I I CH3 ch3 Acetone. Isopropyl alcohol, 2d, by the action of O, which unites directly with an aldehyde to produce the corresponding acid, while it causes the disruption of the molecule of the ketone, with formation of two acids : COH CO,OH ! I ch2 + o = ch2 CH3 CH. Propionic aldehyde. Propionic acid. CH | 3 CO,OH CO,OH CO + 03 = | +| | H CII, CIL Dimethyl ketone — Acetone — Acetylmetliylide—Pyroacetic ether or /CH spirit — CO/^-,jj8—58—is formed as one of the products of the dry dis- tillation of the acetates ; by the decomposition of the vapor of acetic acid at a red heat; by the dry distillation of sugar, tartaric acid, etc.; and in a number of other reactions. It is obtained by distilling dry calcium acetate in an earthenware retort at a dull red heat; the distillate, col- lected in a well-cooled receiver, is freed from II„0 by digestion with fused calcium chloride, and rectified ; those portions being collected which pass over at 60° (140° F.). It is also formed in large quantity in the preparation of aniline. It is a limpid, colorless liquid ; sp. gr. 0.7921 at 18° (64°.4 F.) ; boils at 56° (132°.8F.) ; soluble in H20, alcohol, and ether ; has a peculiar, ethereal odor, and a burning taste ; is a good solvent of resins, fats, camphor, gun- cotton ; readily inflammable. It forms crystalline compounds with the alkaline bisulphites. Cl and Br, in the presence of alkalies, convert it into chloroform or bromoform ; Cl alone produces with acetone a number of chlorinated products of substitution. Certain oxidizing agents transform it into a mixture of formic and acetic acids ; others into oxalic acid. Acetone has been found to exist in the blood and urine in certain pathological conditions, and notably in diabetes ; the peculiar odor exhaled by diabetics is produced by this substance, which has also been considered by some authors as being the cause of the respiratory derangements and coma which frequently occur in the last stages of the disease. That acetone exists in the blood in such cases is certain ; it is not cer- tain, however, that its presence produces the condition designated as acetoncemia. It can hardly be doubted that the acetone thus existing in the blood is indirectly formed from diabetic sugar, and it is probable also that a complex acid, known as ethyidiacetic, C6H903H, is formed as an in- termediate product. Acetone. Formic acid. Acetic acid. MONAMINES. 143 MONAMINES. The monamines are substances which may be considered as being de- rived from one molecule of NH3 by the substitution of one, two, or three alcoholic radicals for one, two, or three H atoms. They are designated as primary, secondary, and tertiary, according as they contain one, two, or three alcoholic radicals: H H H CEL—CH3 II I I N—II N—CIE—CH N—CH—CEE N—CEI—CEE II I I H H CH—CH3 CH—CH3 Ammonia. nh. (C2H6)H2N Ethylamine (primary). (C2H5)2HN Diethylamine (secondary). Triethylamine (tertiary). (C2H6)3N They are also known as compound ammonias, and resemble ammonia in their chemical properties ; uniting with acids, without elimination of H20, to form salts resembling those of ammonium. They also combine with H20 to form quaternary ammonium hydrates, similar in constitution to am- monium hydrate. The alkalinity and solubility in H20 of the primary monamines are greater than those of the secondary, and those of the second- ary greater than those of the tertiary. Their chlorides form sparingly soluble compounds with platinic chloride. The primary monamines are formed by the action of potassium hydrate upon the corresponding cyanic ether : CNO,C2H6 + 2KHO = NH2,C2IIb + C03K2 ; Ethyl cyanate. Potash. Ethylamine. Potassium carbonate. or by heating together an alcoholic solution of ammonia and an ether : C2H6I + NH3 = HI + NH„C,H.; Ethyl iodide. Ammonia. Hydriodic acid. Ethylamine. or by the action of nascent II upon the cyanides of the alcoholic radicals : CN,CH3 + 2H2 = NH2,C2H6. Methyl cyanide. Hydrogen. Ethylamine. The secondary monamines are formed by the action of the iodides or bromides of the alcoholic radicals upon the primary monamines. The tertiary monamines are produced by the distillation of the hy- drates or iodides of the quaternary ammoniums, or by the action of the iodides of the alcoholic radicals upon the secondary monamines. Cpi ) Methylamine—Methylia— jj3 - N—31—is a colorless gas; has a fishy, ammoniacal odor ; inflammable ; is the most soluble gas known, one volume of H.,0 dissolving 1,154 volumes of methylia at 12°.5 (54°.5 F.); the solution is strongly alkaline and caustic. 144 MANUAL OF CHEMISTRY. Dimethylamine—Dimethylia—j N—45—is a liquid below 8° (46°.4 F.) ; has an ammoniacal odor and is quite soluble in II20. Trimethylamine — Trimethylia— (CR3)3N—59—is formed by the action of methyl iodide upon NH3, and as a product of decomposition of many organic substances, it being one of the products of the action of potash on many vegetable substances, alkaloids, etc., of the putrefaction of fish and of starch paste. It also occurs naturally in cod-liver oil, ergot, chenopodium, yeast, guano, herring pickle, human urine, the blood of the calf, and many flowers. It is an oily liquid, having a disagreeable odor of fish ; boils at 9° (48°.2 F.); alkaline ; soluble in II20, alcohol, and ether ; inflammable. It combines with acids to form salts of trimethyl ammonium, which are crystallizable. It has frequently been mistaken by writers upon materia medica for its isomere propylamine, | N, which differs from it in odor and in boiling at 50° (122° F.). Its chloride, under the names chloride of propyla- mia, (f secalia, of secalin, has been used in the treatment of gout and of rheumatism. Tetramethyl ammonium hydrate—(CH3)4N,OH—91.—This sub- stance, w'hose constitution is similar to that of ammonium hydrate, is obtained by decomposing the corresponding iodide, (CH3)4NI, formed by the action of methyl iodide upon trimethylamine. It is a crystalline solid; deliquescent; very soluble in H.,0 ; caustic ; not volatile without decom- position. It attracts carbon dioxide from the air, and combines with acids to form crystallizable salts. The iodide is said to exert an action upon the economy similar to that of curare. Choline; neurine, | —N,OH—121—is a quaternary mon- ammonium hydrate, containing three methyl groups, and one ethylene hydroxide group. It has not as yet been found to exist free in the animal body, but only as a constituent of those important elements of nerve-tissue, the lecithins (q. v.). It was first obtained from bile, but is best prepared from the yolks of eggs. It appears as a thick syrup, soluble in II20 and in alcohol, and strongly alkaline in reaction. Even in dilute aqueous solution it prevents the coagulation of albumin and redissolves coagulated albumin and fibrin. It is a strong base ; attracts carbon dioxide from the air; forms with HC1 a salt, soluble in alcohol, which crystallizes in plates and needles, very much resembling in appearance those of cliolesterin. Choline has been obtained synthetically by the action of a concen- trated solution of trimethylamine upon ethylene oxide, or upon ethylene chlorhydrate. When heated, it splits up into glycol and trimethylamine. By partial oxidation a solid, crystalline base, known as oxyneurine, oxycholine, or betain, is formed. In this substance, which has also been obtained by synthesis, the group C2H4OH is replaced by C2H,0,0H. Choline is isomeric with amanitine, and betain with muscarine; poi- sonous alkaloids obtained from species of Agaricus. There are also amines containing two or more different alcoholic CH’) radicals, such as methyl-ethyl-amylamine, C2H >- N. O.HJ 145 MON AMIDES. MONAMIDES. These bodies differ from the amines in containing oxygenated, or acid radicals, in place of alcoholic radicals. Like the amines, they are divisible into primary, secondary, and tertiary. They are the nitrides of the acid radicals, as the amines are the nitrides of the alcoholic radicals. The monamides may also be regarded as the acids in which the OH of the group COOH has been replaced by (NH2): ch3 I COOH ch3 I conh2 Acetic acid. Acetamide. The primary monamides, containing radicals of the acids of the acetic series, are formed: (1.) By the action of heat upon an ammoniacal salt: = g}o+mo£}, Ammonium acetate. Water. Acetamide. (2.) By the action of a compound ether upon ammonia : <%hs:!»*!|'-(0-h«>+chhI» Ethyl acetate. Ammonia. Acetamide. Alcohol. (3.) By the action of the chloride of an acid radical upon dry NH3 <™; } + 2 (I l N ) = | + (Wj)' | N Acetyl chloride. Ammonia. Ammonium chloride. Acetamide. The secondary monamides of the same class are obtained : (1.) By the action of the chlorides of acid radicals upon the primary amides : (°,H,oy | N +(CAoy j. = (C,HA|N + HJ Acetamide. Acetyl chloride. Diacetamide. Hydrochloric acid. (2.) By the action of HC1 upon the primary monamides at high temperatures : 2((™»+h^(CAO^n + nh.| Acetamide. Hydrochloric acid. Diacetamide. Ammonium chloride. The tertiary monamides of this series of radicals have been but im- perfectly studied; some of them have been obtained by the action of 146 MANUAL OF CHEMISTRY. the chlorides of acid radicals upon metallic derivatives of the secondary amides. The primary monamides containing radicals of the fatty acids are solid, crystallizable, neutral in reaction, volatile without decomposition, mostly soluble in alcohol and ether, and mostly capable of uniting with acids to form compounds similar in constitution to the ammoniacal salts. They are capable of uniting with H20 to form the ammonical salt of the cor- responding acid, and with the alkaline hydrates to form the metallic salt of the corresponding acid, and ammonia. The secondary monamides, containing two radicals of the fatty series, are acid in reaction, and their remaining atom of extra-radical H may be replaced by an electro-positive atom. Acetamide—jj j N—59—is obtained by heating, under press- ure, a mixture of ethyl acetate and aqua ammonite, and purifying by distillation. It is a solid, crystalline substance, very soluble in H20, alcohol, and ether; fuses at 78° (172°.4 F.) ; boils at 221° (429°.8 F.); has a sweetish, cooling taste, and an odor of mice. Boiling potassium hy- drate solution decomposes it into potassium acetate and ammonia. Phos- phoric anhydride deprives it of H20, and forms with it acetonitrile or methyl cyanide. AMIDO-ACIDS OF THE FATTY SERIES. These compounds, also known as glycocols, are of mixed function, acid and basic, obtained by the substitution of the univalent group (NH2)' for an atom of radical H of an acid : ch3 I COOH CH2(NH3) COOH Acetic acid. Amido-acetic acid (glycocol). Some of them, and many of their derivatives, exist in animal bodies. Corresponding to them are many isomeres belonging to other series. Amido-acetic acid—Glycocol—Sugar of gelatin—Glycolamic acid— ch2,nh2 Glycine— | —75—was first obtained by the action of S04H2 upon COOH gelatin. It is best prepared by acting upon glue with caustic potassa, NH3 being liberated ; SOtH„ is then added, and the crystals of potassium sulphate separated; the liquid is evaporated, the residue dissolved in alcohol, from which solution the glycocol is allowed to crystallize. It may also be obtained synthetically by a method which indicates its constitution—by the action of ammonia upon chloracetic acid : CH„C1 H\ CH2NH3 w | ' + H-N =| + ™ COOH H / COOH Chloracetic acid. Ammonia. Amido-acetic acid. Hydrochloric acid. It may be obtained from ox-bile, in which it exists as the salt of a con- jugate acid; from uric acid by the action of hydriodic acid; and by the AMIDO-ACIDS OF THE FATTY SERIES. 147 union of formic aldehyde, hydrocyanic acid, and water. It is isomeric with glycolamide. It has been found to exist free in animal nature only in the muscle of the scallop, and, when taken internally, its constituents are eliminated as urea. In combination it exists in the gelatinoids, and with cholic acid as sodium glycocholate (q. v.) in the bile. It is one of the products of de- composition of glycocholic acid, hyoglycocholic acid, and hippuric acid by dilute acids and by alkalies, and of the decomposition of tissues contain- ing gelatinoids. It appears as large, colorless, transparent crystals; has a sweet taste ; melts at 170° (338° F.); decomposes at higher temperatures; sparingly soluble in cold H20 ; much more soluble in warm H20 ; insoluble in abso- lute alcohol and in ether ; acid in reaction. It combines with acids to form crystalline compounds, which are de- composed at the temperature of boiling water ; hot S04H2 carbonizes it; N03H converts it into glycolic acid (q. v.); with HC1 it forms a chloride ; heated under pressure with benzoic acid it forms hippuric acid. Its acid function is more marked; it expels carbonic and acetic acids from calcium carbonate and plumbic acetate. The presence of a small quantity of glycocol prevents the precipitation of cupric hydrate from cupric sulphate solution by potassium hydrate ; the solution becomes dark blue, does not yield cuprous hydrate on boiling, and precipitates crystalline needles of copper glycolamate on the addition of alcohol to the cold solution. With ferric chloride it gives an intense red solution, whose color is discharged by acids, and reappears on neutralization. With phenol and sodium hypo- chlorite it gives a blue color, as does ammonia. By oxidation with potas- sium permanganate in alkaline solution it yields carbon dioxide, oxalic, carbonic, and oxamic acids, and water. It also forms crystalline com- pounds with many salts and ethers. Methyl amido-acetate is isomeric with sarcosine : ch2nh. I COOH ch2nh, I COOCH3 CH2NH(CH3) I COOH Glycocol (amido-acetic acid). Methyl amido-acetate. Sarcosine (methyl-glycocol). CH2[NH(CH3)] Methyl-glycocol—Sarcosine— | —89—isomeric with COOH alanine and with lactamide (q. v.), does not exist as such in animal nature, but has been obtained from creatine (q. v.) by the action of barium hydrate : C4H9N302 + H20 = C3H7N02 + CON„H4; Creatine. Water. Saroosine. Urea. urea being formed at the same time, and decomposed by the further action of the barium hydrate into NH3 and barium carbonate. Its constitution is indicated by its synthetic formation from chloracetic acid and methylamine : CH2C1 CHq\ CH„[NH(CH3)] w I + H-N = I + Cl COOH H / COOH U1 Chloracetic acid. Methylamine. Sarcosine. Hydrochloric acid. 148 MANUAL OF CHEMISTRY. It crystallizes in colorless, transparent prisms ; very soluble in water; sparingly soluble in alcohol and ether. Its aqueous solution is not acid, and has a sweetish taste ; it unites with acids to form crystalline salts, but does not form metallic salts. It is capable of combining with cyanamide to form creatine. Biliary Acids.—The bile of most animals contains the sodium salts of two amido-acids of complex constitution. These acids may be decomposed into a non-nitrogenized acid (cholic acid), and either an amido-acid (glyco- col), or an amido-sulphurous acid (taurine). The following biliary acids have been described: Glycocholic acid—C26H43N06—465—(sometimes designated as acide cholique, cholsaure, cholic acid, by French and German writers). It exists as its sodium salt in the bile of the herbivora, and in much smaller proportion in that of the carnivora ; it exists in small quantity in human blood and urine in icterus ; in human bile its quantity varies with the diet. It is best obtained from ox-bile ; this is evaporated to one-fourth of its original volume, the residue is ground up with animal charcoal, and dried at 100° (212° F.); the dry mass, while still hot, is broken up and introduced into a flask, in which it is digested with absolute alcohol, writh repeated agitation, for some days ; the colorless, filtered alcoholic solution is partially evaporated, but not to the extent of becoming syrupy, then mixed with an excess of anhydrous ether, which, if the reagents were free from H20, causes the immediate separation of a crystalline precipitate of the mixed biliary salts. If the alcohol or ether used contain H20, the precipitate is at first resinous and only becomes crystalline after standing, or does not become crystalline if the proportion of H20 be too great. The crystalline deposit is collected upon a filter, washed with ether and dissolved in a small quantity of H20 ; to the aqueous solution a small quantity of ether is added, and then enough dilute S04H2 to render the mixture permanently cloudy ; the glycocholic acid gradually crystallizes out, and may be further purified by solution in alcohol, and precipitation with a great excess of ether. Glycocholic acid forms brilliant, colorless, transparent needles, which are sparingly soluble in cold H20, readily soluble in warm H20 and in alcohol, almost insoluble in ether. The watery solution is acid in reac- tion, and tastes at first sweet, afterward intensely bitter. Its alcoholic solu- tion exerts a right-handed polarization [o]D = +29°; when evaporated it leaves the acid in a resinous form. When heated with potash, baryta, or dilute S04II2 or HC1, it is de- composed into cholic acid and glycocol: c26h43no8 + h2o = c24n40o5 + c2h5no2. Glycocholic acid. Water. Cholic acid. Glycocol. Glycocliolic acid dissolves unchanged in cold concentrated SO,H,, and is precipitated on dilution of the solution with H ,0 ; if the mixture be warmed the bile acid is decomposed, and there separate oily drops of cholonic acid, C2(,H4]N05, differing from glycocliolic acid by —H,0. When allowed to remain long in contact with concentrated S04H2, glycocliolic acid is converted into a colorless, resinous mass, which slowly forms a saffron- yellow solution with the mineral acid, which turns flame-red when warmed, and which, on dilution, deposits a flocculent material which is colorless, greenish, or brownish, according to the temperature at which it AMIDO-ACIDS OF THE FATTY SERIES. 149 is formed. Glycocholic acid, altered by contact with concentrated S04H2, absorbs O when exposed to the air, and turns red, then blue, and finally brown after a few days. Sodium Glycocholate, C26H42NOfiNa, exists in the bile ; it crystallizes in stellate needles, very soluble in HO, less so in absolute alcohol, and insoluble in ether ; its acoholic solution exerts right-handed polarization [a]n= +25°.7. Lead Glycocholate, (C2CH42N06)2 Pb (?), is formed as a white, floccu- lent precipitate, when solution of lead subacetate is added to a solution of a glycocholate or of glycocholic acid ; with the neutral acetate the pre- cipitation does not occur in the presence of an excess of acetic acid. It is soluble in alcohol, and in an excess of lead acetate solution. The glycocholates of the alkaline earths are soluble in H20. Gly- cocholic acid and the glycocholates react with Pettenkofer’s test (see below). Glycocholic acid forms compounds with the alkaloids, some of which are crystalline, others amorphous ; they are for the most part very spar- ingly soluble in HaO, but readily soluble in solutions of the biliary salts and in bile. Taurocholic acid—C26H4.N01S—515—{choleic acid of Strecker)— exists as its sodium salt in the bile of man and of the carnivora, and in much less abundance in that of the lierbivora ; in the bile of the dog it seems to be unaccompanied by any other biliary acid. It maybe obtained from dog’s bile by a modification of the method described under glyco- cholic acid ; the watery solution is not treated with S04H„, as in the preparation of that acid, but with solution of basic lead acetate and am- monia. The precipitate so formed is extracted with boiling alcohol, the solution filtered hot and treated with H2S ; the clear liquid, filtered from the precipitated lead sulphide, is evaporated to a small bulk and treated with a large excess of ether ; the acid is precipitated in the resinous form, but, after standing for a varying period, assumes the crystalline form. When carefully prepared it forms silky, crystalline needles, which, when exposed to the air, deliquesce rapidly, and which, even under abso- lute ether, are gradually converted into a transparent, amorphous, resinous mass. It is soluble in H20 and alcohol; insoluble in ether; its aqueous solution is very bitter ; in alcoholic solution it deviates the plane of polar- ization to the right, [a]D= + 24°.5 ; its solutions are acid in reaction. Taurocholic acid is very readily decomposed by heating with barium hydrate, with dilute acids, and even by evaporation of its solution, into cholic acid and taurine: C2,H46N07S + H20 = c24h40o5 + c2h7no3s Taurocholic acid. Water, Cholic acid. Taurine. The same decomposition occurs in the presence of putrefying material and in the intestine. Taurocholic acid has not been found to accompany glycocholic in the urine of icteric patients. The taurocholates are neutral in reaction ; those of the alkaline metals are soluble in alcohol and in water; and by long contact with ether they assume the crystalline form. They may be separated from the glycocho- lates in watery solution, either : (1) by dilute S04H2 in the presence of a small quantity of ether, which precipitates glycocholic acid alone; or (2) by' adding neutral lead acetate to the solution of the mixed salts (which must be neutral in reaction) lead glycocholate is precipitated and separated by 150 MANUAL OP CI1EMISTKY. filtration; to the mother liquor basic lead acetate and ammonia are added, when lead taurocholate is precipitated. The acids are obtained from the hot alcoholic solutions of the Pb salts by decomposition with H2S, filtra- tion, concentration, and precipitation by ether. Solutions of the taurocholates, like those of the glycocholates, have the power of dissolving cholesterin and of emulsifying the fats ; they also form with the salts of the alkaloids compounds which are insoluble in H20, but soluble in an excess of the biliary salt. The taurocholate of morphine is crystallizable. They react with Pettenkofer’s test. Hyoglyeocholic acid, C„7H43KOr, and Hyotaurocholic acid, C27H4i.NO(.S, (?) are conjugate acids of hyocholic add, C25H40O4, and glycocol and taurine, which exist in the bile of the pig. Chenotauroeholic acid, a conjugate acid of taurine and chenocholic add, C27H4404, is obtained from the bile of the goose. Cholic acid—C„4H40O5—408—(cholalic add of Strecker), is a product af decomposition of glyco- and taurocholic acids, obtained as indicated above. It also occurs, as the result of a similar decomposition, in the intestines and faeces of both herbivora and carnivora. It forms large, clear, deliquescent crystals ; sparingly soluble in H20, readily soluble in alcohol and ether ; intensely bitter in taste, with a sweetish aftertaste ; in alcoholic solution it is dextrogyric [a]D = +35°. The alkaline cholates are crystallizable and readily soluble in H„0, the others difficultly soluble. Cholic acid and the cholates respond to Pettenkofer’s test. By boiling with acids or by continued heating to 200° (392° F.), cholic acid loses the elements of H„0, and is transformed into dyslysin, C24H36 03, a neutral, resinous material, insoluble in H20 and alcohol, sparingly solu- ble in ether. The Pettenkofer Reaction.—All of the biliary acids, and the cholic acid and dyslysin obtained by their decomposition, have the property of forming a yellow solution with concentrated SO,H2, the color of which rapidly increases in intensity, and which exhibits a green fluorescence. Their watery solutions also, when treated wTitli a small quantity of cane- sugar and with concentrated S04H2, so added that the mixture acquires a temperature of 70° (158° F.) but does not become heated much beyond that point, develop a beautiful cherry-red color, which gradually changes to dark reddish purple. Although this reaction is observed in the pres- ence of very small quantities of the biliary acids, it loses its value, unless applied as directed below, from the fact that many other substances give the same reaction, either with S04H2 alone, or in the presence of cane- sugar. Among these substances are many which exist naturally in animal fluids, or which may be introduced with the food or as medicines ; such are cholesterin, the albuminoids, lecithin, oleic acid, cerebrin, phenol, tur- pentine, tannic acid, salicylic acid, morphine, codeine, many oils and fats, cod-liver oil, etc. It has been suggested that a distinction could be made between the color produced by the Pettenkofer test with the biliary acids and those produced by the same test with other substances, by spectro- scopic observation ; the test with biliary acids in watery solution exhibit- ing a single dark and broad absorption-band (Fig. 34, No. 2) ; the same test in alcoholic solution shows two bands (No. 1) ; but while this spec- trum differs from those observed in the purple solutions obtained with many other substances, such as albumin (No. 3) ; it does not differ suffi- ciently from that obtained with the morphine salts (No. 4) to render it a safe method for controlling the test. The following method of applying Pettenkofer’s test to the urine and AMIDO-ACIDS OF THE FATTY SERIES. 151 other fluids removes, we believe, every source of error. The urine, etc., is first evaporated to dryness at the temperature of the water-bath, a small quantity of coarse animal charcoal having been added ; the residue is extracted with absolute alcohol, the alcoholic liquid filtered, partially evaporated, and treated with ten times its bulk of absolute ether ; after standing an hour or two, any precipitate which may have formed is col- lected upon a small filter, washed with ether, and dissolved in a small quantity of H,0 ; this aqueous solution is placed in a test-tube, a drop or two of a strong aqueous solution of cane sugar (sugar, 1 ; water, 4), and then pure concentrated S04H2 are added ; the addition of the acid being so regulated, and the test-tube dipped from time to time in cold water, that the temperature shall be from 60°-75° (140°-167° F.). In the pres- ence of biliary acids the mixture usually becomes turbid at first, and then turns cherry-red and finally purple, the intensity of the color varying with the amount of biliary acid present. Fig. 34. Physiological Chemistry oe the Biliary Acids.—These substances do not normally pre-exist in the blood, and are consequently formed in the liver, and they are not reabsorbed from the intestine unchanged. Solu- tions of the biliary salts, injected into the circulation in small quantity, cause a diminution in the frequency of the pulse and of the respiratory movements, a lowering of the temperature and arterial tension, and dis- integration of the blood-corpuscles. In large doses (2-4 grams [30-60 grains] for a dog) they produce the same effects to a more marked degree; epileptiform convulsions, black and bloody urine, and death more or less rapidly. These effects do not follow the injection of the products of decomposition of the biliary acids, except cholic acid, and in that case the symptoms are much less marked. Nor are the biliary acids discharged unaltered with the feces; they are decomposed in the intestine. The extract, suitably purified, of the contents of the upper part of the small intestine, gives a well-marked reaction with Pettenkofer’s test; while similar extracts of the contents of the lower part of the large intestine, or of the feces, fail to give the reaction, and consequently are free from glyco- or taurocholic, cholic acid, or dyslysin ; the feces, more- over, do not contain either taurine or glycocol. During the processes, at 152 MANUAL OF CHEMISTRY. present but imperfectly understood, which take place in the intestine, the bile-acids are undoubtedly decomposed into cholic acid and taurine or glycocol, which are subsequently reabsorbed, either as such, or after having been subjected to further decomposition; and as a consequence of their decomposition they probably have some influence upon intestinal digestion. The biliary salts are precipitated from their aqueous solution, or from bile, by fresh gastric juice from the same animal; but they are not so precipitated if the gastric juice contain peptone. The proportion of biliary salts in human bile seems to vary considerably, as shown by the following analyses : i. II. nr. IV. V. VI. VII. VIII. IX. Mucin 2.G6 2.98 2.21 1.45 2.48 1.29 1.29 Cholesterin 0.16 0.26 ) ( 0.25 0.25 0.34 0.35 Fats 0.32 0.92 J o. uy I 0.04 0.05 0.36 0.73 Taurocholate of sodium, i j.... 0.75 1.93 1.57 0.87 Glycocholate of sodium f ' ’ (4.48 2.09 0.44 4.90 3.03 Soaps 0.64 0.82 1.63 1 46 1 39 Mineral salts 0.65 0.77 1.08 0.63 3.86 0.46? 1.46? Water 86.00 85.92 82.27 89.81 90.88 91.08 Total solids 14.00 14.08 17.73^10.19 9.12 8.92 — .... I. Frerichs : Bile from man, set. 18, killed by a fall. II. Frerichs: Male, set. 22, died of a wound. III. Gorup-Besanez: Male, set. 49, decapitated. IV. Gorup-Be- sanez: Female, set. 29, decapitated. V. Jacobsen: Male, biliary fistula. VI., VII. Trifanowski: Males. VIII. Socolof: Mean of six analyses of human bile. IX. Hoppe- Seyler: Mean of five analyses of bile from subjects with healthy livers. Pathologically, the biliary acids may be detected in the blood and urine in icterus and acute atrophy of the liver, although by no means as frequently as the biliary coloring matters. CH—CH2(NH2) Amidopropionie Acid—Alanine— | —89.—Isomeric COOH with sarcosine and with lactamide ; does not exist, as far as is known at present, in nature. It is obtained by the action of alcoholic ammonia upon bromopropionic acid : CH2Br CH2(NH2) ! /H\ \ I CH2 + 21H—N) = CH2 + BrNH4 I \H/ / | COOH COOH Bromopropi- onic acid. Ammonia. Amidopropi- onic acid. Ammonium bromide. It may also be prepared by starting from lactic acid, from wliicb it differs by containing NH„ in place of OH. It crystallizes in large, oblique, rhombic prisms ; very soluble in H20 ; sparingly soluble in alcohol; insoluble in ether. Its aqueous solution is neutral and sweet. Nitrous acid converts it into lactic acid, N, and H.,0. It dissolves in acids without neutralizing them, but yet, in certain cases, with the formation of crystalline compounds. Its Ba, Pb, Cu, and Ag salts are soluble and crystalline. AMIDO-ACIDS OF THE FATTY SEKIES. 153 Amidobutyric Acid—Butalanine—C4HgN02—and Amidovaleri- anic acid—CsHuNO 3—are only of theoretic interest at present. The latter has been found in the tissue of the pancreas and among the products of the action of pancreatic juice upon albumin. They are among the pro- ducts of the decomposition of albumin by caustic baryta. CH-CsH-CHa(NHs) Amidocaproic Acid—Leucine— | =C0HnNO„ COOH —131—exists widely distributed in animal nature ; it has been obtained from the normal spleen, pancreas, salivary, lymphatic, thymus, and thyroid glands, lungs, and liver. Pathologically, its quantity in the liver is much increased in diseases of that organ, and in typhus and variola ; in the bile in typhus ; in the blood in leucocythsemia, and in yellow atrophy of the liver ; in the urine in yellow atrophy of the liver, in typhus, and in variola ; in choleraic discharges from the intestine ; in pus ; in the fluids of dropsy; and of atheromatous cysts. In these situations it is usually accompanied by tyrosine (q. v.). It is much more abundant in the tissues of the lower forms of animal life, and has also been found in vegetable tissues. It is formed by the decomposition of nitrogenized animal and vegetable substances, by heating with strong alkalies or dilute acids; by the decom- position of elastic tissues it is formed with a small quantity of tyrosine ; by that of gelatinoid materials, leucine and glycine are obtained ; by that of albuminoids, leucine and a small, but variable, quantity of tyrosine are formed ; and that of epidermic tissues yields leucine and tyrosine. It is also one of the products of the putrefaction of animal and vegetable albu- minoids, and of the action of pancreatic juice upon fibrin. It has also been formed synthetically by the action of NH3 upon bromocaproic acid, in the same way that alanine is formed from bromopropiondc acid (see above). It may be obtained by a variety of methods, the most advantageous of which consists in boiling 1 pt. horn-shavings with 4 pts. S04H3 and 12 pts. HaO, for 36 hours, renewing the H20 as it evaporates ; the acid liquid is saturated with milk of lime and boiled again for 24 hours; it is then filtered through linen, a slight excess of S04H3 is added, and the liquid again filtered and evaporated ; tyrosine first crystallizes out and is sepa- rated, after which leucine separates in crystals, which are purified by re- crystallization from a small quantity of H(0, the crystals first formed being rejected. The leucine so obtained is further purified by solution in hot H30 ; digestion with lead hydrate ; filtration ; treatment with H2S ; fil- tration ; treatment with animal charcoal; filtration and crystallization. Leucine crystallines from alcohol in soft, pearly plates, lighter than H20, and somewhat resembling cholesterin ; sometimes in round masses composed of closely grouped needles radiating from a centre. It is spar- ingly soluble in cold H,0 ; readily in warm H20 ; almost insoluble in cold alcohol and ether ; soluble in boiling alcohol, which deposits it on cooling ; it is odorless and tasteless, and its solutions are neutral. Its solubility in H,0 is increased by the presence of acetic acid or of potassium acetate. It sublimes at 170° (338° F.) without decomposition ; if suddenly heated above 180° (356° F.), it is decomposed into amylamine and carbon dioxide. When heated to 1403 (284° F.), with hydriodic acid under pressure, it is decomposed into caproic acid and ammonia. Nitrous acid converts it into leucic acid, CfiH)203, H20 and N. It unites with acids to form solu- ble, crystalline salts. It also dissolves readily in solutions of alkaline hy- drates, forming crystalline compounds with the metallic elements. The formation of leucine in the body is one of the steps of the trans- 154 MANUAL OF CHEMISTRY. formation of at least some part of the albuminoids into urea. That leucine is formed at the expense of the albuminoids by some fermentation-like process, there can be no doubt. As it is only discharged in the urine in certain exceptional pathological conditions, and as at the same time the elimination of urea is greatly diminished, it seems highly probable that under normal conditions the N of leucine finally makes its exit from the body as urea, notwithstanding the fact that chemists have hitherto been unable to obtain urea from leucine artificially. As to the nature of the changes by which leucine is converted into urea in the body, we are as yet in the dark. When leucine and tyrosine appear in the urine, that fluid is poor in urea and usually contains biliary coloring matters; the substitution of leucine for urea may be so extensive that the urine con- tains no urea, and contains leucine in such quantity that it crystallizes out spontaneously. Analytical Characters.—The presence of leucine and tyrosine in the urine may be detected as follows : the freshly collected urine is treated with basic lead acetate, filtered, the filtrate treated with H2S, filtered from the precipitated lead sulphide, and the filtrate evaporated over the water- bath ; leucine and tyrosine crystallize ; they may be separated by extrac- tion of the residue with hot alcohol, which dissolves the leucine and leaves the tyrosine. The leucine left by evaporation of the alcoholic solu- tion may be recognized by its crystalline form and by the following characters : (1) a small portion is moistened on platinum foil with NO.H, which is then cautiously evaporated ; a colorless residue remains, which, when warmed with caustic soda solution, turns yellow or brown, and by further concentration is converted into oily drops, which do not adhere to the platinum (Scherer’s test); (2) a portion of the residue is heated in a dry test-tube ; it melts into oily drops, and the odor of amylamine (odor of ammonia combined with that of fusel oil) is observed ; (3) if a boiling mixture of leucine and solution of neutral lead acetate be carefully neu- tralized with ammonia, brilliant crystals of a compound of leucine and lead oxide separate; (4) leucine carefully heated in a glass tube, open at both ends, to 170° (338° F.), sublimes without fusing, and condenses in flocculent shreds, resembling those of sublimed zinc oxide. If heated be- yond 180° (356° F.), the decomposition mentioned in 2d occurs. Tyrosine—C6HnN03 —145—is a substance which does not belong to this series, and is probably an amido-acid of the aromatic series ; neverthe- less, as its constitution is still undetermined, and as it is almost universally found to accompany leucine in animal tissues and in the products of their decomposition, it may be considered in this place. The methods of its formation and preparation are given under leucine. It crystallizes from its watery and ammoniacal solutions in silky needles, arranged in stellate bundles ; very sparingly soluble in cold H20 ; almost insoluble in alcohol ; more soluble in hot H„0. When heated, it turns brown and yields an oily matter having the odor of phenol ; when heated in small quantities to 270° (518° F.), it is decomposed into carbon dioxide and a white solid, having the composition CgHuNO, which sublimes. It combines with both acids and bases. It has been found in animal nature in the same situations as leucine. When taken into the stomach it is not altered in the economy, but is eliminated in the urine and fames. Analytical Characters.—(1) its crystalline form ; (2) when heated it does not sublime, but gives off an odor resembling that of phenol; (3) when moistened on platinum foil with NOaH and this carefully evaporated, COMPOUNDS OF ALCOHOLIC RADICALS. 155 it dissolves and leaves a deep yellow residue, which, when moistened with sodic hydrate solution, turns deep yellowish-red and leaves, on evapora- tion of the H30, a dark brown residue (Scherer) ; (4) when moistened on a porcelain dish with concentrated S04H2 and slightly warmed, it dis- solves with a transient red color ; the solution, diluted with Ho0, neutral- ized with calcium carbonate and filtered, gives a liquid to which a neutral solution of ferric chloride communicates a violet color (Piria) ; (5) if boiled with a solution of acid nitrate of mercury, a pink color is first observed, and later a red px*ecipitate (Hoffmann, L. Meyer). Creatine—C4H9N302 +Aq—131 + 18—is another complex amido-acid, which occurs as a normal constituent of the juices of muscular tissue, voluntary and involuntary, of brain, blood, and amniotic fluid. It is best obtained from the flesh of the fowl, which contains 0.32 per cent., or from beef-heart, which contains 0.14 per cent., by hashing, warming with alcohol and expressing strongly ; the alcohol is distilled oflj the residual liquid precipitated with lead acetate, filtered, treated with H„S, again filtered, the filtrate evaporated to a syrup, from which the creatine crystallizes. It is soluble in boiling H,0 and in alcohol, insoluble in ether; crystallizes in brilliant, oblique, rhombic prisms ; neutral, tasteless, loses aq. at 100° (212° F.) ; fuses and decomposes at higher temperatures. When long heated with HaO or treated with concentrated acids, it loses H O, and is converted into creatinine. Baryta water decomposes it into sarcosine and urea. It is not precipitated by silver nitrate, except when it is in excess and in presence of a small quantity of potassium hydrate ; the white precipitate so obtained is soluble in excess of potash, from which a jelly separates which turns black, slowly at ordinary temperatures, rapidly at 100° (212° F.). A white precipitate, which turns black when heated, is also formed when a solution of creatine is similarly treated with mercuric chloride and potash. Creatinine—C4H7N30—113—a product of the dehydration of crea- tine, is a normal and constant constituent of the urine and amniotic fluid, and also exists in the blood and muscular tissue. It crystallizes in oblique, rhombic prisms, soluble in H.,0 and in hot alcohol; insoluble in ether. It is a strong base, has an alkaline taste and reaction ; expels N H3 from the ammoniacal salts, and forms well-defined salts, among which is the double chloride of zinc and creatinine (C4H7N3 0)2ZnCl2, obtained in very sparingly soluble, oblique prismatic crystals, when alcoholic solutions of creatinine and zinc chloride are mixed. The quantity of creatinine eliminated is slightly greater than that of uric acid, 0.6-1.3 gram (9.25-20 grains) in 24 hours ; it is not increased by muscular exercise, but is diminished in progressive muscular atrophy. It is obtained from the urine by precipitation with zinc chloride. COMPOUNDS OF THE ALCOHOLIC RADICALS WITH OTHER ELEMENTS. The organic substances hitherto considered are composed, of seven ele- ments only : C, H, 0, N, Cl, Br and I; but compounds of C containing every known element have been observed to exist in nature, or have been pro- duced artificially. Of these quite a number may be considered as con- taining the radicals of the series C„H2n+1, which exist in the monoatomic alcohols. These bodies are almost exclusively the products of the labora- 156 MANUAL OF CHEMISTRY. tory, and resemble in constitution some of the compounds already con- sidered. Sulphides.—The compounds of the alcoholic radicals with S are the same in constitution as those with O, S taking the place of O : C-H{ I O" c2hJ° c2h6 i s„ C2H6 f b Ethyl hydrate (alcohol). Ethyl oxide (ether). Ethyl sulphydrate (mercaptan). Ethyl sulphide, Ethyl Sulphydrate, usually known as mercaptan, from its tendency to unite with mercury (corpus mercurium captans), is formed in a variety of reactions. It is best prepared by treating alcohol with SO,!!.,, as in the preparation of sulphovinic acid (q. v.); mixing the crude product with excess of potash ; separating from the crystals of potassium sulphate; saturating with H ,S ; and distilling. It is a mobile, colorless liquid; sp. gr. 0.8325 ; has an intensely disa- greeable odor, combined of those of garlic and H2S ; boils at 36°.2 (97°. 2 F.) ; ignites readily and bums with a blue flame ; may be readily frozen by the cold produced by its own evaporation ; neutral in reaction ; sparingly soluble in H20, soluble in all proportions in alcohol and ether ; dissolves I, S and P. Potassium and sodium act with mercaptan as with alcohol, replacing the extra-radical hydrogen. In its behavior toward the oxides it more closely resembles the acids than the alcohols, being capable even of enter- ing into double decomposition to form salts, called sulphethylates or mer- captides. Its action with mercuric oxide is characteristic, forming a white, crystalline sulphide of ethyl and mercury : 2 (°’h |s) + He"° = (C,Hg'’}s. + H.° Ethyl sulphydrate. Mercuric oxide. Ethyl-mercuric sulphide. Water. Ethyl Sulphide, a colorless liquid ; having a penetrating, disagreeable odor of garlic ; boiling at 73° (163°.4F.) ; insoluble in H20, soluble in alcohol; inflammable; obtained by the action of ethyl chloride upon potassium sulphide. Phosphines, arsines, and stibines are compounds resembling the amines in constitution, in which the N is replaced by P, As, or Sb. Like the amines, they may be primary, secondary, or tertiary : CaH5) hIn H) H >- P c2h8) C2H , [ As H) CJIJ C.,H. [ Sb. c:hJ Ethylamine (primary). Ethylphospine (primary). Diethyl-arsine (secondary). Triethyl-stibine (tertiary). There also exist compounds containing P, As, or Sb, which are similar in constitution to the hydrates and salts of ammonium, and of the com- pound ammoniums : NH4I N(CHs)4I As(CH3)4I Ammonium iodide. Tetramethyl ammonium iodide. Tetramethyl arsenium iodide. ALLYLIC SERIES. 157 Most of these compounds, which are very numerous, are as yet only of theoretic interest. One of them, however, is deserving of notice here : CH3 ) V Dimethyl Arsine, CH, > As—106—which may be considered as being H) the hydride of the radical [As(CH3) J, does not exist as such; there is however, a liquid known as the fuming liquor of Cadet, or alkarsin, which is obtained by distilling a mixture of potassium acetate and arsenic trioxide. This liquid contains the oxide of the above radical, and a sub- stance which ignites on contact with air, and which consists of the same radi- cal united to itself 2[As(CH3)J. This radical, called cacodyle (kolk6s = evil), is capable of entering into a great number of other combinations. Cacodyle and its compounds are all exceedingly poisonous, especially the cyanide, an ethereal liquid, very volatile, the presence of whose vapor in inspired air, even in minute traces, produces symptoms referable both to arsenic and to hydrocyanic acid. Organo-metallie substances are compounds of the alcoholic radi- cals with metals. They are very numerous, usually obtained by the action of the iodide of the alcoholic radical upon the metallic element, in an atmosphere of H. They are substances which, although they have been put to no uses in the arts or in medicine, have been of great service in chemical research. As typical of this class of substances we may men- tion : Zinc-ethyl—q'jj5 | Zn—123—obtained by heating at 130° (266° F.) in a sealed tube a mixture of perfectly dry zinc amalgam with ethyl iodide ; the contents of the tube are then distilled in an atmosphere of coal-gas, or H, and the distillate collected in a receiver, in which it can be sealed by fusion of the glass without contact with air. It is a colorless, transparent, highly refracting liquid; sp. gr. 1.182 ; boils at 118° (244°.4 F.). On contact with air it ignites and burns with a luminous flame, bordered with green, and gives off dense clouds of zinc oxide, a property which renders it very dangerous to handle. On contact with HO it is immediately decomposed into zinc hydrate and ethyl hydride! It is chiefly useful as an agent by which the radical ethyl can be introduced into organic molecules. ALLYLIC SERIES. The compounds heretofore considered may be derived more or less directly from the saturated hydrocarbons ; in the derivatives, as in the hydrocarbons, the valences of the C atoms are all satisfied, and that in the simplest and most complete manner, two neighboring C atoms always exchanging a single valence. There exist, however, other compounds, containing less H in proportion to C than those already considered, and yet resembling them in being monoatomic. These compounds have usually been considered as non-saturated, because all the possible valences are not satisfied, and the substances are therefor capable of forming pro- ducts of addition, while the saturated compounds can only form products of substitution. In this sense the substances composing this series are non-saturated, but they are not so in the sense that they contain C or other atoms whose valences are not satisfied. The following formulas indicate the constitu- 158 MANUAL OF CHEMISTRY. tion of the substances of this series, and their relation to those of the pre- vious one. It will be observed that in the allyl compounds two neighbor- ing C atoms exchange tiuo valences : CH3 ch2 I ch2h or (CSH,)' ) Hf ch3 I ch2 ch2oh or (C:|H H } 0 CH3 I ch2 I COH or (C3H50)' | Hi CH3 I ch2 I COOH or (c.H.oy | o fCHsl I ch2 I ch2 I (CSH ,)' Propyl hydride (hydrocarbon). Propyl hydrate (alcohol). Propionyl hydrate (aldehyde). Propionyl hydrate (acid). Propyl (radical). r chi ii 2 CH I CHJ or c3h5) C3H5 ) ch2 II CH I ch2oh or <0,H£}o CH2 II CH COH or (C3H30)' ) Hf ch2 II CH I COOH or (CAoyjo ch2] II CH I iH ((TO Diallyl (hydrocarbon). Allyl hydrate (alcohol). Acrolein (aldehyde). Acrylic acid (acid). Allyl (radical). Cjj ) Diallyl—q8jj6 r —82—formerly known as allyl, is obtained by the action of sodium upon allyl iodide, and is not, as its empirical formula would seem to indicate, a superior homologue of acetylene and allylene (q. u). It is a colorless liquid, having a peculiar odor, somewhat resembling that of horseradish ; boils at 59° (138°.2 F.); sp. gr. 0.684 at 14° (57°.2 F.). C H ) Allyl hydrate—Allylic alcohol— 3 - O—58—may be obtained by the action of sodium upon dichlorhydrine in ethereal solution ; or by heating four parts of glycerin with one part of crystallized oxalic acid. Allvlic alcohol is a colorless, mobile liquid ; solidifies at —54° (—65°.2 F.); boils at 97° (206°.6 F.); sp. gr. 0.8507 at 25° (77° F.); soluble in H20 ; has an odor resembling the combined odors of alcohol and essence of mustard ; burns with a luminous flame. Allyl alcohol is isomeric with propylic aldehyde and with acetone. Being an unsaturated compound, it is capable of forming products of addition with Cl, Br and I, etc., which are isomeric or identical with pro- ducts of substitution obtained by the action of the same elements upon glycerin. Oxidizing agents convert it first into acrolein, acrylic alde- hyde, CsH40, and finally into acrylic acid. It does not combine readily with H, but in the presence of nascent H combination takes place slowly, with formation of propylic alcohol. ALLYLIC SERIES. 159 CHI Allyl oxide—Allylic ether—q3jj5 r O—98—exists in small quantities in crude essence of garlic. It is obtained as a colorless liquid, having an alliaceous odor ; insoluble in H20 ; boiling at 82° (179°.6 F.), by a num- ber of reactions, but best by the action of allyl iodide upon sodium allyl oxide. C H ) Allyl sulphide—essence of garlic—q3jj" c S—114—is obtained by the action of an alcoholic solution of potassium sulphide upon allyl iodide ; also as a constituent of the volatile oil of garlic, by macerating garlic, or other related vegetables, in water, and distilling. Crude essence of garlic is thus obtained as a heavy, fetid, brown oil ; this is purified by redistilla- tion below 140° (284° F.) ; contact with potassium and subsequent redis- tillation from calcium chloride. It is a colorless, transparent oil; lighter than H.20, sparingly soluble in H20, very soluble in alcohol and ether; boils at 140° (280° F.); has an in- tense odor of garlic. It does not exist naturally in the plant, but is formed during the process of extraction by the action of H,0, probably in a man- ner similar to that in which essence of mustard is formed under similar circumstances. It is to the formation of allyl sulphide, which is highly volatile, that garlic owes the odor which it emits. Allyl sulphocyanate—Essential oil of mustard—Oleum sinapis vola- tile (U S.)—| S—99.—If the seeds of white or black mustard be strongly expressed, a bland, neutral oil is obtained, which resembles rape- seed and colza oils in its physical properties, and in being composed of the glycerides of stearic, oleic, and erucic acids. The cake remaining after the expression of this oil from black mustard, or the black-mustard seeds themselves, pulverized and moistened with H20, gives off a strong, pun- gent odor. If the H20 be now distilled, a volatile oil passes over with it, which is the crude essential oil of mustard. In practice the powdered cake of black-mustard seeds, from which the fixed oil has been expressed, is digested with H20 for 24 hours, after which the H20 is distilled as long as any oily matter passes over ; the oil is col- lected, dried by contact with calcium chloride, and redistilled. Essence of mustard may also be obtained synthetically by the action of allyl bro- mide or iodide upon potassium sulphocyanate, or by the action of allyl iodide upon silver sulphocyanate. This essence does not exist preformed in the mustard, but results from the decomposition of a peculiar constituent of the seeds, potassium myro- nate, determined by cryptolytic action set up by another constituent, myro- sine, in the presence of H20. Potassium myronate exists only in appreciable quantity in the black variety of mustard, from which it may be obtained in the shape of short prismatic crystals, transparent, odorless, bitter ; very soluble in H20, sparingly so in alcohol. Myrosine is a nitrogenized cryptolite, existing in the white as well as in the black mustard, and in other seeds. It may be obtained from white- mustard seeds, in an impure form, by extraction with cold H20, filtering and evaporating the solution at a temperature below 40° (104° F.) ; the syrupy fluid so obtained is precipitated with alcohol, the precipitate washed with alcohol, redissolved in H20, and the solution evaporated below 40° (104° F.) to dryness. At temperatures above 40° (104° F.) myrosine becomes coagulated and 160 MANUAL OF CHEMISTRY. incapable of decomposing potassium myronate, a change which is also pro- duced by contact with acetic acid. As the rubefacient and vesicant ac- tions of mustard when moistened with H20, are due to the production of allyl sulphocyanate, neither vinegar, acetic acid, nor heat greater than 40° (104° F.) should be used in the preparation of mustard cataplasms. Pure allyl sulphocyanate is a transparent, colorless oil; sp. gr. 1.015 at 20° (68° F.) ; boils at 143° (289°.4 F.); has a penetrating, pungent odor, sparingly soluble in H20, very soluble in alcohol and ether. WThen exposed to the light it gradually turns brownish yellow and deposits a re- sinoid material. When applied to the skin it produces rubefaction, quickly followed by vesication. ACIDS AND ALDEHYDES OF THE ACRYLIC SERIES. These substances bear the same relation to the alcohols of the allyl series that the volatile fatty acids and the corresponding aldehydes bear to the ethylic series of alcohols. The following terms of the series have been obtained : Acids. CnH2a_202, Acrylic acid C302H4 Orotonic C402H9 Angelic C602H8 Pyroterebic C9O2H10 Oleic C1802H34 Aldehydes. CnHaD„_aO. Acrolein C30H4 Crotonic Aldehyde C4OH9 The acids of this series differ from those containing the same number of C atoms in the formic series, by containing two atoms of H less ; they are readily converted into acids of the formic series by the action of potas- sium hydrate in fusion. QJJO) Acrylic acid— 3 3jj > O—72—is obtained by oxydation of acrolein by silver oxide, and is formed in a number of other reactions. It is a col- orless, highly acid liquid ; has a penetrating odor ; solidifies at 7° (44°.6 F.); boils at 140° (284° F.). Nascent H unites with it to form propionic acid. It forms crystalline salts and ethers. Acrylic aldehyde—Allylic aldehyde—Acrolein—C3H30 | When the fats and fixed oils are decomposed by heat, a disagreeable, irri- tating odor is produced, which is due to the formation of acrolein by the dehydration of the glycerin contained in the fatty material. Acrolein may be obtained by heating glycerin with strong S04H„, or with hydropotassic sulphate. Glycerin is the alcohol (hydrate) of a radical having the same composition as allyl, but so differing from it in constitution as to be triva- lent in place of univalent. (C3H&)'"(OH)3 = 2H20 + (C3H30)'H Glycerin. Water. Acrolein. Acrolein is a colorless, limpid liquid ; lighter than H20 ; boils at 52°.4 (126°.3 F.) ; sparingly soluble in H20, more soluble in alcohol; very vola- tile ; its vapor is very pungent and irritating. When freshly prepared it is neutral in reaction, but on contact with air it rapidly becomes acid by oxidation. For the same reason it does not keep well, even in closed ves- ACIDS AND ALDEHYDES OF THE ACRYLIC SERIES. 161 sels ; on standing it deposits a flocculent material, which has been called disocryl, while at the same time formic, acetic, and acrylic acids are formed. Oxydizing agents convert it into acrylic acid, or, if they be energetic, into a mixture of formic and acetic acids. The caustic alkalies produce from it resinoid substances similar to those formed from acetic aldehyde. With NH3 it forms a crystalline, odorless compound, which behaves as a base. Acrolein is formed whenever glycerin, or any substance containing it or its compounds with the fatty acids, is heated to a temperature sufficient to effect its decomposition ; for this reason, and because of the irritating action of the acrolein, the heavy petroleum-oils are preferable to those of vegetable or animal origin for the lubricating of machinery operated in en- closed places. C H O ) Crotonic acid— 4 6jj v O—86—was first obtained from croton-oil, oleum tiglii (U S.), oleum crotonis (Br.), in which it exists in combination with glycerin, and accompanied by the glycerin ethers of several other fatty acids ; it is, however, neither the vesicant nor the purgative prin- ciple of the oil. It may be obtained by saponification of croton-oil, or, better, by the action of potassium hydrate upon allyl cyanide. It is an oily liquid ; solidifies at —5° (23° F.) ; acrid in taste ; gives off highly irritating vapors at temperatures slightly above 0° (32° F.). When taken internally it acts as an irritant poison. An acid obtained by oxidation of crotonic aldehyde is probably an iso- mere, as it is in the form of crystals at ordinary temperatures, and only fuses at 73° (163°.4F.). Crotonic aldehyde—jj j- —70.—If aldehyde, H20, and HC1, be mixed together at a low temperature, and the mixture exposed to diffused daylight for some days, an oily liquid is formed, which, after purification, has the composition C4H80,. This substance, known as aldol, when ex- posed to heat, is decomposed into water and crotonic aldehyde : C4H6Oa = HjO + C4HeO. Crotonic aldehyde is a colorless liquid ; boils at 105° (221° F.) ; gives off highly irritating vapors. It bears the same relation to croton chloral that aldehyde does to chloral. C H Cl O ) Croton chloral—Trichlorocroton aldehyde— 4 a 3jj v—173.5—a substance which has been used as an anaesthetic whose action is particu- larly directed to the sensory nerves distributed to the head and face. It is prepared by directing a current of Cl through acetic aldehyde, as ordin- ary chloral is obtained by the action of Cl upon ethylic alcohol. The first action is to convert ethylic aldehyde into crotonic aldehyde by condensa- tion and elimination of H30 ; in the second stage of the reaction the substitution of three atoms of Cl for an equal number of atoms of H in the croton aldehyde thus formed takes place. OHO) Angelic acid— 5 7jj V O—100—exists in angelica root, in the flow- ers of chamomile, Anthemis (U. S.), and in croton-oil. It crystallizes in colorless prisms, which fuse at 45°. 5 (113°.9 F.) ; boils at 185° (365° F.); has an aromatic odor and an acid, pungent taste ; sparingly soluble in cold HaO ; readily soluble in hot 11,0, alcohol, and ether. By the action of heat it is converted into its isomere, methylcro- tonic acid, c | q 11 162 MANUAL OF CHEMISTRY. C H O) Oleic acid—Acidum oleicum (U. S.)— 18 33jj V O—246—exists as its glyceric ether, olein, in most, if not in all the fats and in all fixed oils. It is obtained in an impure form on a large scale as a by-product in the manufacture of candles. This product is, however, very impure ; to purify it, it is first cooled to 0° (32° F.), the liquid portion collected ; cooled to —10° (14° F.), expressed, and the solid portion collected ; this is melted and treated with half its weight of massicot; the lead oleate so obtained is dissolved out by ether ; the decanted ethereal solution is shaken with HC1, the ethereal layer decanted and evaporated, when it leaves oleic acid, contaminated with a small quantity of oxyoleic acid, from which it can be purified only by a tedious process. Pure oleic acid is a white, pearly, crystalline solid, which fuses to a colorless liquid at 14° (57°.2 F.); it is odorless and tasteless ; soluble in alcohol, ether, and cold S04Ha; insoluble in H20 ; sp. gr. 0.808 at 19° (66°.2 F.). Neutral in reaction. It can be distilled in vacuo without decom- position, but when heated in contact with air, it is decomposed with formation of hydrocarbons, volatile fatty acids, and sebacic acid. It dis- solves the fatty acids readily, forming mixtures whose consistency varies with the proportions of liquid and solid acid which they contain. The solid acid is but little altered by exposure to air, but when liquid it absorbs O rapidly, becomes yellow, rancid, acid in reaction, and incapable of solidifying when cooled; these changes take place the more rapidly the higher the temperature. Cl and Br attack oleic acid with formation of products of substitution. If oleic acid be heated with an excess of caustic potassa to 200° (392° F.), it is decomposed into palmitic and acetic acids ; C18HS4Oa -t- 2KHO = C16H3102K + C2H302K + H,; a reaction which is utilized industrially to obtain hard soaps, palmitates, from olein, which itself only forms soft soaps. Cold S04H2 dissolves oleic acid, and deposits it unaltered on the addition of H20, but if the acid solution be heated it turns brown and gives off S02. Nitric acid oxidizes it energetically, with formation of a number of volatile fatty acids and acids of another series—suberic, adipic, etc. The oleates of the alkaline metals are soft, soluble soaps ; those of the earthy metals are insoluble in H20, but soluble in alcohol and in ether. Elaidic acid is an isomere of oleic acid, produced by the action upon it of nitrous acid in the preparation of Unguentum hydrargyri nitratis (U. S. ; Br.). The nitrous fumes formed convert the oleic acid, contained in the oil and lard used, into elaidic acid, which exists in the ointment in combination with mercury. POLYATOMIC COMPOUNDS. The organic compounds hitherto considered may be looked upon as compounds of univalent carbon radicals, these radicals existing in the al- cohols and acids in combination with an atom each of O and H ; they are called monoatomic because they contain a siugle atom of H capable of being replaced by an alcoholic radical. There exist other C compounds, in which the radicals, containing a less number of H atoms as compared with the number of C atoms, have a valence greater than one ; these radi- cals form acids, alcohols, etc., in which the number of atoms of replaceable H is greater than one, and which are designated as polyatomic. HYDROCARBONS. 163 1st Series. C„KWS 2d Series. 3d Series. CnH,n_, 4th Series. c„h2„_4 5th Series. C„H2„_6 6th Series. CnH2n_8 7th Series. **—10 8th Series. CkH9»-,4 9th Series. c„h9»_14 10th Series. C„H2„_lg 11th Series. C„H2n_]8 0H4 Methane. c„h8 C^H* Calls Ethane. Ethene. Acetylene. C3H8 c3h8 C3H4 Propane. Propene. Allylene. c4h10 c4h8 C4H8 c4h4 Butane. Butene. Crotonylene. CsHu C5H10 C6H8 c6h8 Pentane. Pentene. Valery lene. Valylene. C8Hh C0Hu C8H8 c8h8 Hexane. Hexene. Hexylene. Benzene. CtHu c,h14 C7H1S 1 C7H,o C7H8 Heptane. Heptene. CEnanthylidene Toluene. CsHis CsHie C8H14 c8hI3 C8H8 Octane. Octene. Caprylidene. Xylene. Cinnamene. C9H30 CaHis c»h14 Nonane. Nonene. Cuinene. c10h8 Decane. Decene. Decenylene. Terebenthene. Cymene. Naphthydrene. Naphthalene. CuHjo CiiHj8 CuHio TJndecane. Undecene. Laurene. Dodecane. Dodecene. Acenaphthalene. C13H3S Cl3H26 Ci3H34 C43Haa c13h„ CisHis CisHiu CisHu Ci3H:a CisHio Tridecane. Tridecene. Fluorene. CuH,o Cl4H28 Oi4Hq8 Ci4H34 Ci4Hqs CwHso Ci4His CuHis Cj4Hu c14h, a ChH10 Tetradecane. Tetradecene. Stilbene. Anthracene. HYDROCARBONS. 164 MANUAL OF CHEMISTRY. NON-SATURATED HYDROCARBONS. Besides the compounds of C and H described on pp. 110 et seq., in which all the valences of the C atoms are satisfied, either by the attachment of H atoms, or by the interchange of a single valence between neighboring C atoms, there exist many others in which the proportion of H to C is less. These compounds are non-saturated, in this, that they are capable of unit- ing directly with atoms of other elements, or with radicals, to form pro- ducts of addition, while the composition of the saturated hydrocarbons can only be modified by substitution ; they are not, however, to be consid- ered as containing any unsatisfied valence. These hydrocarbons are very numerous, and may be arranged in ho- mologous series, as shown in the table on page 163, each succeeding series containing a less amount of H in proportion to the C : SECOND SERIES OF HYDROCARBONS—OLEFINES. Sekies CnH2„. The terms of this series contain two H atoms less than the correspond- ing terms of the first series ; they differ in constitution in this, that, while in the first series a single valence is exchanged between each two neighboring C atoms, in the second series two valences are exchanged be- tween two of the C atoms: c=h3 I C=H, c-H3 c-h3 I C-H II c=h, Propane. Propylene. They are designated as olefines ; or, to distinguish them from the terms of the first series, by the terminations ylene or ene, thus the second is called ethylene or ethene. They behave as bivalent radicals. Ethene—Ethylene—Olefiant gas—Elayl—Heavy carburetted hydro- CH* gen— || —28—is formed by the dry distillation of fats, resins, wood, CH’ and coal, and is one of the most important constituents of illuminating gas. It is also obtained by the dehydration of alcohol or ether. It has been obtained synthetically: (1) by passing a mixture of HaS and carbon monoxide over iron or copper heated to redness; (2) by heat- ing acetylene in the presence of H, or by the action of nascent H upon copper acetylide ; (3) by the action of H upon the chloride C„C14, obtained by the action of Cl upon carbon disulphide. It is prepared in the labora- tory by the dehydration of alcohol: a mixture of 4 pts. S04H„ and 1 pt. alcohol is placed in a flask containing enough sand to form a thin paste, and gradually heated to about 170° (338° F.) ; the gas, which is given off in abundance, is purified by causing it to pass through wash-bottles con- taining HaO, an alkaline solution, and concentrated S04Ha. DIATOMIC ALCOHOLS. 165 Pure ethylene is a colorless gas ; tasteless ; has a faint odor resembling that of salt water, or an ethereal odor when impure ; irrespirable ; spar- ingly soluble in H.,0, more soluble in alcohol. It burns with a luminous, white flame, and forms explosive mixtures with air and oxygen. When heated for some time at a dull red heat it is converted into acetylene, ethyl and methyl hydrides, a tarry product, and carbon. Ethylene readily enters into combination. It unites with H to form ethyl hydride, C,H6. With O it unites explosively on the approach of a flame, with formation of carbon dioxide and H20. Oxidizing agents, such as potassium permanganate in alkaline solution, convert it into oxalic acid and H20. A mixture of Cl and ethene, in the proportion of two volumes of the former to one of the latter, unite with an explosion on contact with flame, the union being attended with a copious deposition of C and the formation of HC1. Chlorine and ethene, mixed in equal volumes and ex- posed to diffused daylight, unite slowly, with formation of an oily liquid ; ethene chloride, C2H4C12=Dutch liquid, to whose formation ethene owes the name olefiant gas. By suitable means ethene may also be made to yield chlorinated products of substitution, the highest of which is carbon dichloride, C2C14. Br and I also form products of addition and of substitu- tion with ethene. By union with (OH)2 it forms glycol (q. v.). It slowly dissolves in ordinary S04H„, with formation of sulphovinic acid ; with fuming S04H2 it combines with elevation of temperature and formatio'n of ethionic anhydride. When inhaled, diluted with air, ethene produces effects somewhat similar to those of nitrous oxide. Pentene—Amylene or valerene—C6HI0—70—a colorless, mobile liquid, boiling at 39° (102°.2 F.) ; obtained by heating alcohol with a concentrated solution of zinc chloride. Its use as an anaesthetic has been suggested. CH2C1 Ethene chloride—Bichloride of ethylene—Dutch liquid— | —99 CH2C1 —is obtained by passing a current of ethene through a retort in which Cl is being generated, and connected with a cooled receiver. The dis- tillate is washed with a solution of caustic potassa, afterward with H20, and is finally rectified. It is a colorless, oily liquid, which boils at 82.5° (180°. 5 F.); has a sweet- ish taste and an ethereal odor. It is isomeric with the chloride of mo- C2H4C1 nochlorinated ethyl, | , which boils at 64° (147°. 2 F.). It is capable Cl of fixing other atoms of Cl by substitution for H, and thus forming a series of chlorinated derivatives, the highest of which is C2C1„. DIATOMIC ALCOHOLS. Series CnH2n+202. These substances are usually designated as glycols. They are the hydrates of the hydrocarbons of the series CnH,n, and consist of those hydrocarbons, playing the part of bivalent radicals, united with two groups OH ; their general typical formula is then (CnH.,n)" ) Q We have geen ) (p. 116) that the primary monoatomic alcohols contain the group of 166 MANUAL OF CHEMISTRY. atoms (CH,OH), united with n(CnH,n_v_1); the primary glycols are simi- larly constructed, and consist of twice the group (CH,OH), united in the higher terms to n(CH,). The constitution of the glycols and their rela- tions to the monoatomic alcohols are indicated by the following formulae : ch2oh I I CH CHpH I I ch2oh Primary propyl alcohol. Primary propyl glycol. As the monoatomic alcohols are such by containing in their molecules a group (OH), closely attached to an electro-positive group, and capable of removal and replacement by an electro-negative group or atom, so the glycols are diatomic by the fact that they contain two such groups (OH). As the monoatomic alcohols are therefor only capable of forming a single ether with a monobasic acid, the glycols are capable of forming two such others: CHa (C2H302)' ch3 ch3 (c2h3o2)' I ch2oh CH, (C3H302)' CH2 (C2H302)' Ethyl acetate Monoacetic glycol. Diacetic glycol. ch2oh Ethene glycol—Ethylene glycol or Alcohol or Hydrate— | — CH2OH 62 This, the best known of the glycols, is prepared by the action of dry silver acetate upon ethylene bromide. The ether so obtained is purified by redistillation, and decomposed by heating for some time with barium hydrate. It is a colorless, slightly viscous liquid ; odorless ; faintly sweet; sp. gr. 1.125 at 0° (32° F.); boils at 197° (386°.6 F.) ; sparingly soluble in ether; very soluble in water and in alcohol. It is not oxidized by simple exposure to air, but on contact with plati- num black it is oxidized to glycolic acid ; more energetic oxidants trans- form it into oxalic acid. Chlorine acts slowly upon glycol in the cold ; more rapidly under the influence of heat, producing chlorinated and other derivatives. By the action of dry HC1 upon cooled glycol, a product is formed, intermediate between it and ethylene chloride, a neutral com- ch3oh pound—ethene chlorhydrate or ethene chlorhydrin, | , which boils at CH2C1 130° (266° F.). Ethene oxide—Ethylene oxide— (C,H4)"0 —44.—This substance, iso- meric with aldehyde, is obtained by the action of potassium hydrate upon ethene chlorhydrate. It is a transparent, volatile liquid ; boils at 13°.5 (54°. 3 F.) ; gives off inflammable vapors ; mixes with H„0 in all proportions. It is capable of uniting directly with H20 to form glycol; and with HC1 gas to regenerate ethene chlorhydrate. Taurine—SO?C.,H7N—125 —is isomeric with a derivative of glycol, isethionamide. It is obtained from ox-bile by boiling with dilute HC1; ACIDS DERIVED FROM THE GLYCOLS. 167 decanting and concentrating the liquid ; separating from the sodium chlo- ride which crystallizes ; evaporating further, and precipitating with alco- hol. The deposit is purified by recrystallization from alcohol. It crystallizes in large, transparent, oblique, rhombic prisms, permanent in air, soluble in H20, almost insoluble in absolute alcohol and ether. Taurine has acid properties and forms salts ; it is not attacked by S04H2, NOsH, or nitromuriatic acid, but is oxidized by nitrous acid, with formation of H20, N, and isethionic acid. It exists in the animal economy, in the bile in taurocholic acid (q. v.) ; and has also been detected in the intestine and faeces, muscle, blood, liver, kidneys, and lungs. The pneumic acid, described as existing in the lung, is taurine. When taken internally, it is eliminated by the urine, not in its own form, but as taurocarbamic or isethionuric acid, C3H8N2S06. ACIDS DERIVED FROM THE GLYCOLS. As the acids of the acetic series are obtained from the primary mono- atomic alcohols by the substitution of O for H2 in the characterizing group CH2OH: CH3 I ch2,oh ch3 I CO,OH Ethyl alcohol. Acetic acid. so the diatomic alcohols may, by oxidation, be made to yield acids, formed by the same substitution of O for H2. But the glycols differ from the monoatomic alcohols in containing two groups CH2OH, and they con- sequently yield two acids, as the substitution occurs in one or both of the alcoholic groups : CH,,OH I CH„OH CH2,OH I CO,OH CO, OH I CO,OH Ethene glycol. Glycolic acid. Oxalic acid. A study of these two acids shows them to be possessed of peculiar differences of function. Each of them contains two groups (OH), whose hydrogen is capable of replacement by an acid or alcoholic radical: CH,,OC2H3 CHo,0H ch3oc,,h, CO,oh co,oc2hs I I I ' J I I COOH CO,OC3H5 CO,OC2H3 CO,OC2H5 co,oc2h5 Ethylglycolic acid. Ethyl glycolate. Ethyl etliylglycolate. Ethyloxalic acid. Ethyl oxalate. They are, therefor, both said to be diatomic. The ability, however, of the two acids to form salts is not the same, for while oxalic acid is capable of forming two salts of univalent metals, and a salt of a bivalent metal with a single molecule of the acid ; glycolic acid only forms a single salt of an univalent metal, and two of its molecules are required to form a salt of a bivalent metal ; in other words, glycolic acid is monobasic while oxalic acid is dibasic. It is only that H atom which is contained in the electro-nega- tive group COOH, which is replaceable as acid hydrogen, while that of 168 MANUAL OF CHEMISTRY. the electro-positive group CH2OH is only replaceable, as is the correspond- ing hydrogen of an alcohol. In general terms, therefor, the atomicity of an organic acid may be greater than its basicity, the former representing the number of H atoms contained in its molecule, which are capable of being displaced by alco- holic radicals, while the latter represents the number of H atoms re- placeable by electro-positive elements or radicals, with formation of salts or of ethers. There may, therefor, be obtained from the glycols, by more or less complete oxidation, two series of acids; those of the first are diatomic and monobasic ; those of the second diatomic and dibasic. DIATOMIC AND MONOBASIC ACIDS. Sekies C„HsBOs. The acids of this series at present known are (Carbonic acid) C03H2 I Glycolic acid C203H4 Ethyleno-lactic acid C303H6 | Butylactic acid C403H8 I Oxyvaleric acid C5O3H)0 Leucio acid C603H12 (?) CEnanthic acid C1403H28 The first-named of these acids, although not capable, so far as yet known, of existing in the free state, is widely represented in nature in the shape of its salts, the carbonates. Its position in this series is an anomaly, and at first sight a contradiction, as it is certainly not a mono- basic, but a distinctly dibasic acid, or, more properly speaking, would be such were it obtained in a state of purity. It is, however, in this position, as the inferior homologue of glycolic acid, that carbonic acid is most naturally placed, and the dibasic nature of the latter acid does not pre- sent any valid objection to such a position, for if we consider one term of a series as derivable from its superior homologue by the subtraction of CH2, and if we bear in mind that the basic nature of the hydrogen atom in a group OH depends upon its close union with the group CO (or with some other electro-negative group), it will become evident that the in- ferior homologue of glycolic acid must contain two groups OH united to one CO, and must, therefor, be dibasic: CHaOH OH /OH | - CH2 = | or CO/^g CO,OH CO,OH XUil Glycolic acid. Carbonic acid. The other acids of the series are formed : (1.) By the partial oxidation of the corresponding glycol: CHOH CH OH xj-v I + O. = I + f>0 CHaOH CO,OH Glycol. Glycolic acid. Water. OXIDES OF CARBON. 169 (2.) By the combined action of water and silver oxide upon the mono- chlor-acid of the acetic series, or by heating the alkaline salt of such an acid with water or potassium hydrate: ch2ci ch2oh I + £>0 = I + KC1 COOK CO,OH Potassium monochloracetate. Water. Glycolic acid. Potassium chloride. (3.) By reducing the corresponding acid of the oxalic series by nascent hydrogen : COOH CH2OH | + 2Ha = | + g>0 COOH COOH Oxalic acid. Glycolic acid. Water. Carbonic acid—CC)/q^—62.—Although this acid has not been isolated, it probably exists in aqueous solutions of C02, which have an acid reaction, while dry C02 is neutral. Its salts, the carbonates, are well char- acterized. Oxides of Carbon. Carbon monoxide—Carbonous oxide—Carbonic oxide—CO—28. Formation.—(1.) By burning C with a limited supply of air. (2.) By passing dry carbon dioxide over red-hot charcoal. (3.) By heating oxalic acid with S04H2: C204H2 = H20 -f CO + C0„; and passing the gas through sodic hydrate to separate C02. (4.) By heating potassium ferrocyanide with S04H2. Properties.—A colorless, tasteless gas; sp. gr. 0.9678A; very sparingly soluble in H,0 and in alcohol. It burns in air with a blue flame and formation of carbon dioxide ; it forms explosive mixtures with air and oxygen ; it is oxidized to carbon dioxide by cold chromic acid. It is a valuable reducing agent, and is used for the reduction of metallic oxides at a red heat. Ammoniacal solutions of the cuprous salts absorb it readily. Being non-saturated, it unites readily with O to form C02, and with Cl to form C0C12, the latter a colorless, suf- focating gas, known as phosgene, or carbonyl chloride. Toxicology.—Carbon monoxide is an exceedingly poisonous gas, and is the chief toxic constituent of the gases given off from blast-furnaces, from defective flues, and open coal or charcoal fires, and of illuminating gas. An atmosphere containing but a small proportion of this gas pro- duces asphyxia and death, even if the quantity of oxygen present be equal to or even greater than that normally existing in the atmosphere ; 0.5 per cent, of CO in air is sufficient to kill a small bird in a few moments, and one per cent, proves fatal to small mammals. Poisoning by CO may occur in several ways. By inhalation of the gases discharged from blast-furnaces and from copper-furnaces, the former con- taining 25 to 32 per cent., and the latter 13 to 19 per cent, of CO. By the fumes given off from charcoal burned in a confined space, which con- sist of a mixture of the two oxides of carbon, the dioxide predominating 170 MANUAL OF CHEMISTEY. largely, especially when the combustion is most active. The following is the composition of an atmosphere produced by burning charcoal in a con- fined space, and which proved rapidly fatal to a dog : oxygen, 19.19 ; nitro- gen, 76.62; carbon dioxide, 4.61; carbon monoxide, 0.54; marsh-gas, 0.04. Obviously the deleterious effects of charcoal-fumes are more rapidly fatal in proportion as the combustion is imperfect and the room small and ill-ventilated. A fruitful source of CO poisoning, sometimes fatal, but more frequently producing languor, headache, and debility, is to be found in the stoves, furnaces, etc., used in heating our dwellings and other buildings, especially when the fuel is anthracite coal. This fuel produces in its combustion, when the air-supply is not abundant, considerable quantities of CO, to which a further addition may be made by a reduction of the dioxide, also formed, in passing over red-hot iron ; this poisonous gas may find its way into the rooms either through cracks or other defects in the stoves, flues, or pipes ; by occasional downward currents of air passing over fires in open fireplaces, or, much more frequently, by direct passage through the heated metal. Experiment has shown that metals, notably cast-iron, are quite pervious to gases when heated to redness ; when, therefor, a stove or the fire-box of a hot-air furnace becomes red-hot, a portion of the gases, formed by the combustion of the fuel, passes through the pores of the metal to contaminate the air without, and gives rise to CO poisoning to a degree dependiirg upon the degree of imperfection of the ventilation, the nature of the fuel, and the amount of air supplied to it. The precautions required to avoid this form of what may be called chronic CO poisoning, and which is by no means uncommon, are : (1) To have the stoves or furnaces lined with fire-clay, which tends to prevent their overheating and to diminish their perviousness to gases ; (2) to avoid heating to redness ; (3) to furnish an abundant supply of air to the fuel; (4) to secure proper ventilation ; and (5), in the case of hot-air furnaces, to obtain, by an abun- dant supply of external air to the air-chamber, a large supply of moderately heated air rather than a small quantity of very hot air. Of late years cases of fatal poisoning by coal-gas are of very frequent occurrence, caused either by accidental inhalation, by inexperienced per- sons blowing out the gas, or by suicides. The most actively poisonous in- gredient of coal-gas is CO, which exists in the ordinary illuminating gas in the proportion of 4 to 7.5 per cent., and in water-gas, made by decompos- ing superheated steam by passage over red-hot coke, and subsequent charging with vapor of hydrocarbons, in the large proportion of 30-35 per cent. The method in which CO produces its fatal effects is by forming with the blood-coloring matter a compound which is more stable than oxyhsemo- globin, and thus causing asphyxia by destroying the power of the blood- corpuscles of carrying O from the air to the tissues. This compound of CO and haemoglobin is quite stable, and hence the symptoms of this form of poisoning are very persistent, lasting until the place of the coloring-mat- ter thus rendered useless is supplied by new-formation. The prognosis is very unfavorable when the amount of the gas inhaled has been at all con- siderable ; the treatment usually followed, i.e., artificial respiration, and inhalation of 0, failing to restore the altered coloring-matter. There would seem to be no form of poisoning in which transfusion of blood is more directly indicated than in that by CO. Detection after death.— The blood of those asphyxiated by CO is per- sistently bright red in color. When suitably diluted and examined with OXIDES OF CARBON-. the spectroscope, it presents an absorption spectrum (Fig. 35) of two bands similar to that of oxyhsemoglobin (Fig. 14, No. 11) but in which the two bands are more equal and somewhat nearer the violet end of the spectrum. Owing to the greater stability of the CO compound, its spectrum may be readily distinguished from that of the O compound by the addition of a reducing agent (an ammoniacal solution of ferrous tartrate), which changes the spectrum of oxyhaemoglobin to the single-band spectrum of haemo- globin (Fig. 14, No. 12), while that of the CO compound remains unaltered, or only fades partially. If a solution of caustic soda of sp. gr. 1.3 be added to normal blood, a black, slimy mass is formed, which, when spread upon a white plate, has a greenish-brown color ; the same reagent added to blood altered by CO forms a firmly clotted mass, which in thin layers upon a white surface is bright red in color. Fig. 35. For the method of detecting and determining CO in gaseous mixtures, see p. 178. Carbon dioxide—Carbonic anhydride—Carbonic acid gas—C03—44. Preparation.—(1.) By burning C in air or O. (2.) By decomposing a carbonate (marble = C03Ca) by a mineral acid (HC1 diluted with an equal volume of H20). Properties.—At ordinary temperatures and pressures it is a colorless, suffocating gas ; has an acidulous taste ; sp. gr. 1.529A ; soluble in an equal volume of H20 at the ordinary pressure ; much more soluble as the pressure increases. Soda water is a solution of carbonic acid in H20 under increased pressure. When compi-essed to the extent of 38 atmospheres at 0° (32° F.); 50 atm. at 15° (59° F.); or 73 atm. at 30° (86° F.) it forms a transparent, mobile liquid, by whose evaporation, when the pressure is relieved, sufficient cold is produced to solidify a portion into a snow-like mass, which by spontaneous evaporation in air, produces a temperature of -90° (-130° F.). Carbon dioxide neither burns nor does it support combustion. When heated to 1,300° (2,370° F.), it is decomposed into CO and O. A similar de- composition is brought about by the passage through it of electric sparks. When heated with H it yields CO and H20. When K, Na or Mg is heated in an atmosphere of C02, the gas is decomposed with formation of a car- bonate and separation of carbon. When caused to pass through solutions of the hydrates of Na, K, Ca, or Ba, it is absorbed, with formation of the carbonates of those elements, which, in the case of the last two, are de- posited as white precipitates. Solution of potash is frequently used in analysis to absorb C02, and lime and baryta water as tests for its presence. The hydrates mentioned also absorb C02 from moist air. Atmospheric Carbon Dioxide.—Carbon dioxide is a constant constituent of atmospheric air in small and varying quantities ; the mean amount in free country air being about 4 in 10,000. The variations in amount under different conditions is shown in the following table : 172 MANUAL OF CHEMISTRY. Amount or Carbon Dioxide in Air. Collected at Parts in 10,000. Determined by Paris 3.190 Boussingault and Lewy. Boussingault and Lewy. Boussingault. Boussingault. Lewy. Lewy. Saussure. Andilly—twenty miles from Paris 2.989 Paris—Day 3.9 Night 4.2 Ocean—Day 5.42 Night 3.346 Geneva 4.68 Meadow—three-fourths mile from Geneva : Dry months 4.79 to 5.18 Saussure. After long rains 3.57 to 4.56 Saussure. December, damp and cloudy January, frost 3.85 to 4.25 4.57 Saussure. January, thaw 4.27 Saussure. Lake Geneva 4.39 Saussure. Arctic regions 4.83 to 6.41 Moss. Gosport barracks 6.45 Chaumont. Anglesey barracks 14.04 Chaumont. Hilsey Hospital 4.72 Chaumont. Portsmouth Hospital 9.76 Chaumont. Cell in Pentonville Prison 9.89 Chaumont. Cell in Chatham Prison 16.91 Chaumont. Boys’ school—69 cubic feet per head 31.0 Roscoe. Room—51 cubic feet per head 52.8 Weaver. Girls’ school—150 cubic feet per head 72.3 Pettenkofer. Greenhouse—Jardin des Plantes 1.0 Theatre—Parquet. 23.0 Near ceiling 43.0 Lead mine—Lamps burn 80.0 F. Leblanc. Lamps extinguished 390.0 F. Leblanc. Grotto del Cane 7,360.0 F. Leblanc. It will be observed that on land the amount is greater by night than by day, while the reverse is the case at sea; on land the green parts of plants absorb C02 during the hours of sunlight, but not during those of darkness. The increase in the amount in air over large bodies of water during the daytime is due to the less solubility of C02 in the surface- water when heated by the sun’s rays. The absence of vegetation accounts for the large quantity of C02 in the air of the polar regions, and the same cause, aided by an increased production, for its excess in the air of cities over that of the country. The sources of atmospheric C02 are : (1.) The respiration of animals.—The air expired from the lungs of animals contains a quantity of C02, varying with the age, sex, food, and muscular development and activity, while, at the same time, a much smaller quantity is discharged by the skin and in solution in the urine. In females the increase of elimination follows the same rule as with males until puberty, when it ceases, and the amount exhaled remains about the same until the menopause, when the elimination of C02 suddenly in- creases to nearly the same as that occurring in males of the same age, and subsequently gradually declines with advancing age. During pregnancy the elimination of C02 is temporarily increased. In both sexes and at all ages the exhalation of C02 is greater during muscular activity than when the individual is at rest, and greater in those whose muscular development is more perfect. An adult man discharges 20.77 litres = three-fourths cubic foot, of C03 per hour, or 498.88 litres = 18 cubic feet, per diem. greater by night than ad the green parts of 173 OXIDES OF CARBOX. The following table, from the experiments of Andral and Gavarret, indi- cates the quantity of C02 eliminated by males of various ages : Elimination of Carbon Dioxide. Age. Mean weight. Carbon elim- inated, in grams. Carbon diox- ide elimina- ted, in grams Oxygen ab- sorbed, in grams. Carbon diox- ide elimina- ted, in litres. Oxygen ab- sorbed, in litres. In kilos. In lbs. In 1 hour. In 24 hours. Ini hour. In 24 hours. In 1 hour. In 24 hours. Ini hour. In 24 hours. In 1 hour. In 24 hours. 8 years 22.26 49.07 5.0 120.8 18.3 442.9 15.613 374.70 9.30 225.16 8.63 207.22 15 years... 46.41 102.32 8.7 208.8 31.9 765.6 27.166 651.98 16.21 389 22 18.91 453.89 16 years 58.39 117.70 10.8 259.2 39.6 950.4 33.723 809.36 20.13 483.17 23.48 563.42 18 to 20 years 60.88 134.22 11.4 273.6 41.8 1003.2 35.599 854.32 21.25 510.01: 24.78 594.79 20 to 24 years 66.90 147.49 12.2 292.8 44.7 1073.6 38.094 914.28 22.72 545.81 26.52 686.47 40 to 60 years 67.15 148.04 10.1 242.4 37.0 888.8 31.537 756.89 18.81 451.85 21.95 526.92 60 to 80 years 63.35^139.66 9.2 220.8 33.7 809.6 28.727 689.45 17.13 411.59 20.00 479.98 The expired air under ordinary conditions contains about 4.5 per cent, by volume of C02, the proportion being greater the slower the respiration. (2.) Combustion.—The greater part of the atmospheric C02 is a pro- duct of the oxidation of C in some form as a source of light and heat. In the following table are given the amounts of C02 produced, and of air consumed, by different kinds of fuel and illuminating materials ; by com- paring them with the quantities of the same gases produced and consumed by an adult man it will be seen that, in equal times, an ordinary gas-burner produces nearly six times as much C02, and consumes nearly ten times as much air as a man. The amount of air consumed by fuel is, for practical pur- poses, greater than that given in the table, as the oxidation is never com- plete, the air in the chimney frequently containing ten per cent, of oxygen by volume (see below). Combustion of Fuel. Fuel. Average amount burned in one hour. Average per- centage of Carbon dioxide duced by pro- Air deoxidized by Heat units. 1 Light in standard candles, 100. Carbon. Hydrogen. One volume in vol- umes. One part by weight in parts by weight. one hour. | One volume in vol- umes. One kilo in cubic metres. In one hour. In kilos. In litres. In kilos. In litres. Hydrogen 100.0 2.39 26.89 34462 Carbon to C02 100.0 3.65 9.83 8080 Carbon to CO" 100.0 4.93 2474 Carbon monoxide ... 42.86 1.0 i.57 2.39 0.44 2403 76.0 25.09 1.0 2.75 9.55 13.45 13063 86.72 14.2S 2.0 3.14 14.33 12.67 11857 Coal-gas 140 litres 40.0 55.0 0.80 1.67 0.221 112 7.14 11.04 1.293 1000 11000 Crude petroleum 84.0 13.0 3.08 12.07 11775 87.0 13.0 3.17 0.048 25 12.12 0.235 i§2 11055 180 Wax 10 gr. 79.2 13.2 2.89 0.029 15 11.24 0.146 113 10496 100 76.05 12.68 2.9 0.029 15 8.69 0.112 86.9 9716 84 Colza-oil 42 gr. 70.43 10.5 2.81 0.118 60 8.28 0.450 348 159 Wood (dry pine) 39.10 4.90 1.4a • • • • 5.16 3600 Wood charcoal 85.0 3.10 8.36 7640 Peat 45.0 1.5 1.64 4.82 3000 87.0 3.17 8.55 Anthracite 90.0 2.5 3.29 9.22 6000 52.17 13.04 1.90 8.64 7ia3 Adult man 10 gr. C 0.037 19 ... 0.134 104 174 MANUAL OF CHEMISTRY. (3.) Fermentation.—Most fermentations, including putrefactive changes, are attended by the liberation of C03; thus, alcoholic fermentation takes place according to the equation: C6HJ=Oe = 2C2H60 + 2C0„ 180 92 44 and consequently discharges into the air 44 parts by weight of C02 for every 92 parts of alcohol formed, or 191.5 litres of gas for every litre of absolute alcohol obtained. (4.) Tellural sources.—Volcanoes in activity discharge enormous quan- tities of C02, and, in volcanic countries, the same gas is thrown out abun- dantly through fissures in the earth. All waters, sweet and mineral, hold this gas in solution, and those which have become charged with it under pressure in the earth’s crust, upon being relieved of the pressure when they reach the surface, discharge the excess into the air. (5.) Manufacturing processes.—Large quantities of C02 are added to the air in the vicinity of lime- and brick-kilns, cement-works, etc. (6.) In mines, after explosions of “fire-damp.” These explosions are caused by the sudden union of the C and H of CH4 with the O of the air, and are consequently attended by the formation of large volumes of COs, known to miners as after-damp. Constancy of the amount of atmospheric carbon dioxide.—It has been roughly estimated by Poggendorff that 2,500,000,000,000 cubic metres of C02 are annually discharged into our atmosphere, and that this quantity represents one eighty-sixth of the total amount at present existing therein. This being the case, with the present production, the percentage of atmos- pheric C02 would be doubled in eighty-six years ; no such increase has, however, been observed, and the average percentage found by Angus Smith, in 1872, is about the same as that observed by Boussingault in 1840, i.e., four parts in ten thousand. The C02 discharged into the air is, therefor, removed from it about as fast as it is produced. This removal is effected in two ways : (1) by the formation of deposits of earthy carbonates by animal organisms, corals, mollusks, etc.; (2) principally by the process of nutrition of vegetables, which absorb C02 both by their roots and leaves, and in the latter, under the influence of the sun’s rays, decompose it, retaining the C, which passes into more complex molecules ; and dis- charging a volume of O about equal to that of the C03 absorbed. Air contaminated urith excess of carbon dioxide, and its effects upon the organism.—When, from any of the above sources, the air of a given locality has received sufficient C02 to raise the proportion above 7 in 10,000 by volume, it is to be considered as contaminated ; the seriousness of the contamination depending not only upon the amount of the increase, but also upon the source of the C02. If the gas be derived from fermen- tation, or from tellural or manufacturing sources, it is simply added to the otherwise unaltered air, and the absolute amount of oxygen present remains the same ; when, however, it is produced in a confined space by the processes of combustion and respiration, the composition of the air is much more seriously modified, as not only is there addition of a de- leterious gas, but a simultaneous removal of an equal volume of O ; hence the importance of providing, by suitable ventilation, for the supply of new air from without to habitations and other places where human beings are collected within doors, especially where the illumination is artificial. Although an adult man deoxidizes a little over 100 litres of air in an hour, a calculation of the quantity which he would require in a given time 175 OXIDES OF CARBOX. cannot be based exclusively upon that quantity, as the deoxidation cannot be carried to completeness ; indeed, when the proportion of COtJ in air ex- ceeds five per cent., it becomes incapable of supporting life, while a much smaller quantity, one per cent., is provocative of severe discomfort, to say the least. In calculating the quantity of air which should be supplied to a given enclosed space, most authors have agreed to adopt as a basis that the per- centage of C02 should not be allowed to exceed 0.6 volume per 1,000 ; of which 0.4 is normally present in air, and 0.2 the product of respiration or combustion. Taking the amount of COa eliminated by an adult at 19 litres (=0.7 cubic foot) per hour, a man will have brought the air of an air-tight space of 100 cubic metres (=3,500 cubic feet) up to the permis- sible maximum of impurity in an hour. The following table is given by Parkes to indicate the contamination of air by the respiration of an adult in an hour, and the supply of external air required to restore the proper equilibrium : Amount of cubic space (breathing- space) for one man in cubic feet. Ratio per 1,000 of C02 from respiration at the end of one hour, if there have been no change of air. Amount of air neces- sary to dilute to standard of 0.2, or in- cluding initial C02, of 0.6 per 1,000 vol- umes during the first hour. Amount necessary to dilute to the given standard every hour after the first. 100 6.00 2,900 3,000 200 3.00 2,800 3,000 300 2.00 2,700 3,000 400 1.50 2,600 3,000 500 1.20 2.500 3,000 600 1.00 2,400 3,000 700 0.85 2,300 3,000 800 0.75 2,200 3,000 900 0.66 2,100 3,000 1,000 0.60 2,000 3,000 Practically, owing to the imperfect closing of doors and windows, and to ventilation by chimneys, inhabited spaces are never hermetically closed, and a less quantity of air-supply than that indicated in the table may usually be considered as sufficient. A sleeping-room occupied by a single person should have a cubic space of 30 to 50 cubic metres (==1,050 to 1,800 cubic feet), conditions which are fulfilled in rooms measuring 10 x 13 x 8 feet, and 13 x 15.6 x 9 feet. In calculating the space of dormitories to be occupied by several healthy people, the smallest air-space that should, under any circum- stances, be allowed, is 12 cubic metres (=420 cubic feet) for each person, To determine the number of individuals that may sleep in a room, multi- ply its length, width, and height together, and divide the product by 420 if the measurement be in feet, or by 12 if it be in metres. Thus, a dor- mitory 40 feet long, 20 feet wide, and 10 feet high, is fitted for the ac- commodation of 19 persons at most; for 40 x 20 x 10 = 8,000 and = 19.05. As a rule, in places where many persons are congregated, it is neces- sary to resort to some scheme of ventilation by which a sufficient supply 176 MANUAL OF CHEMISTRY. of fresh air shall be introduced and the vitiated air removed, the quantity to be supplied varying according to circumstances. Experiment has shown that, in order to keep the air pure to the senses, the quantity of air which must be supplied per head and per hour in temperate climates are as shown in the table : which must be as shown in th< Situation. Cubic metres. Cubic feet. Situation. Cubic metres. Cubic feet. Barracks (daytime) 35 1,236 Hospital wards (surgical) 170 6,004 Barracks (night-time) 70 2,472 Contagious and lying-in.. 170 6,004 Workshops (mechanical) 70 2,472 Mines, metalliferous 150 6,297 35 1,236 170 6,004 Hospital wards 85 3,002 The amounts given are the smallest permissible, and should be ex- ceeded wherever practicable. Lights.—The amount of air to be supplied to each individual, given in the last section, are, with the exception of those furnished in mines, based upon the supposition that coal-gas is not used as a means of artificial il- lumination, or that the burners are so arranged with reference to the ventilating-flues that the products of combustion pass out immediately. Each cubic foot of illuminating-gas consumes in its combustion a quan- tity of O equal to that contained in 7.14 cubic feet of air, and produces 0.8 cubic feet of CO„, besides a large quantity of watery vapor, and less amounts of S04H2, SO„, and sometimes CO ; and an ordinary gas-burner consumes about three feet per hour. It is obvious, therefor, that a much larger quantity of pure air must be furnished to maintain the atmosphere of an apartment at the standard of 0.6 per 1,000 of C02, when the vitia- tion is produced by the combustion of gas, than when it is the result of the respiration of a human being, and that to such an extent that a single three-foot burner requires a supply of air which would be sufficient for six human beings. As a basis for computation, it may be considered that, for each cubic foot of gas consumed, 1,800 cubic feet of air should be furnished by ventilation. The contamination of air by gas-lights becomes a question of serious importance in our dwellings upon occasions of social gatherings, and in theatres and other places of public resort which are used during the hours of darkness. The average size of a parlor in a city dwelling is 15 x 25 x 15 feet ; it therefor contains 4,875 cubic feet, and its atmosphere would, if it were hermetically closed, be brought to the standard of maximum allow- able contamination by the respiration of four adults in an hour, allowing 1,200 cubic feet per head, per hour. If such an apartment be illuminated, upon the occasion of an evening party at which fifty adults are present for four hours, by ten three-feet gas-burners, the amounts of air which should be supplied by ventilation are as follows in cubic feet: If the products of combus- tion of gas be discharged into the room. If the products of combus- tion of the gas be carried off. Per hour. Forfour hours. Per hour. For four hours. For fifty persons 60,000 54,000 240,000 216,000 60,000 240,000 114,000 456,000 60,000 240,000 OXIDES OF CARBOX. 177 In the first instance, in which the products of the combustion of gas are discharged into the apartment, an adequate ventilation can only be secured by a complete change of the air every 2.6 minutes, which can only be attained by the use of mechanical contrivances, and with the production of draughts ; in the second instance, in which it is presumed that the gas-burners are so situated, with reference to a ventilating-shaft or shafts, that the products of combustion are immediately carried off, not only is the period in which a complete change of air is required ex- tended to 4.8 minutes, but the heat of the burners, causing an uptake current in the ventilator, favors the exit of the vitiated air, and the con- sequent entrance of external air to take its place. In theatres the contamination of the air by the burning of gas should be entirely eliminated by placing the burners either under the dome ven- tilator, or in boxes which open to the air of the house only below the level of the burner, and which are in communication with a ventilating- shaft. Even under these conditions *it is necessary, to ensure perfect ventilation, to resort to some mechanical contrivance to remove the air vitiated by respiration and to supply its place by fresh air from without, which may be previously warmed or cooled according to the season, and which, in cities, should be filtered. When artificial illumination is obtained from lamps or candles, or from gas in small quantity and for a shoi’t time, the contamination of the air is sufficiently compensated by the ventilation through imperfect closing of the windows. A room without a window should never be used for human habitation. One important advantage of the electric light, if it ever become prac- ticable, will be that it consumes no O and produces no C02. Although, by the combustion of fuel, O is consumed and C02 pro- duced, heating arrangements only become a source of vitiation of air under the circumstances detailed above (see p. 170) ; indeed, in the majority of cases, if properly arranged, they are the means of ventilation, either by aspirating the vitiated air of the apartment, or by the introduction of air from without. Action on the economy.—An animal introduced into an atmosphere of pure C02 dies almost instantly, and without entrance of the gas into the lungs, death resulting from spasm of the glottis, and consequent apnoea. When diluted with air, the action of C02 varies according to its pro- portion, and according to the proportion of O present. First.—When the proportion of O is not diminished, the poisonous action of C02 is not as manifest, in equal quantities, as when the air is poorer in oxygen. An animal will die rapidly in an atmosphere composed of 21 per cent. O, 59 per cent. N, and 20 per cent. C02 by volume ; but will live for several hours in an atmosphere whose composition is 40 per cent. O, 37 per cent. N, 23 per cent. C02. If C02 be added to normal air, of course the relative quantity of O is slightly diminished, while its absolute quantity remains the same ; this is the condition of affairs existing in nature when the gas is discharged into the air ; under these circumstances an addition of 10-15 per cent, of CO„ renders an air rapidly poisonous, and one of 5-8 per cent, will cause the death of small animals moi’e slowly. Even a less proportion than this may become fatal to an individual not habituated. In the higher states of dilution, CO„ produces immediate loss of mus- cular power, and death without a struggle ; when more dilute, a sense of irritation of the larynx, drowsiness, pain in the head, giddiness, gradual loss of muscular power, and death in coma. 178 MANUAL OF CHEMISTRY. Second.—If the CO,, present in air be produced by respiration or com- bustion, the proportion of O is at the same time diminished, and much smaller absolute and relative amounts of the poisonous gas will produce the effects mentioned above ; thus, an atmosphere containing in volumes 19.75 per cent. O, 74.25 per cent. N, G per cent. C02, is much more rapidly fatal than one composed of 21 per cent. O, 59 per cent. N, 20 per cent. CO,,. With a corresponding reduction of O, 5 per cent, of C02 ren- ders an air sufficiently poisonous to destroy life ; 2 per cent, produces severe suffering; 1 per cent, causes great discomfort, while 0.1 per cent., or even less, is recognized by a sense of closeness. The treatment in all cases of poisoning by C02 consists in the inhalation of pure air (to which a small excess of O may be added), aided, if neces- sary, by artificial respiration, the cold douche, galvanism, and friction. When it chances that an individual entering an atmosphere containing an excess of C02, or other noxious gas, is seen to fall insensible, it is simply multiplying the number of* victims, for others to follow, unpro- tected, with a view to effecting a rescue. Probably the most readily ob- tainable protection is a towel saturated wdtli lime-water, and so held over the mouth and nostrils that the inspired air passes through it, and also through two or three layers of dry towelling interposed between the moist- ened part and the skin. Detection of carbon dioxide and analysis of confined air.—Carbon dioxide, or air containing it, causes a white precipitate when caused to bubble through lime or baryta water ; normal air contains enough of the gas to form a scum upon the surface of these solutions when exposed to it. It was at one time supposed that air in which a candle continued to burn was also capable of maintaining respiration. This is, however, by no means necessarily true; a candle introduced into an atmosphere in which the normal proportion of O is contained, burns readily in the presence of 8 per cent, of CO„; is perceptibly dulled by 10 per cent.; is usually extin- guished with 13 per cent.; always extinguished with 16 per cent. Its ex- tinction is caused by a less proportion of CO,, 4 per cent., if the quantity of O be at the same time diminished. Moreover, a contaminated atmos- phere may not contain enough CO,, to extinguish, or perceptibly dim the flame of a candle, and at the same time contain enough of the monoxide to render it fatally poisonous if inhaled. The presence of C02 in a gaseous mixture is determined by its absorp- tion by a solution of potash ; its quantity either by measuring the diminu- tion in bulk of the gas or by noting the increase in weight of an alkaline solution. To determine the proportions of the various gases present in air the apparatus shown in Fig. 36 is used. A is an aspirator of known capacity, filled with water at the beginning of the operation. It connects by a flexible tube from its upper part with an absorbing apparatus con- sisting of a, a U-shaped tube containing fragments of pumice stone, moist- ened with SO.H„; by the increase in weight of this tube the weight of watery vapor in the volume of air drawn through by the aspirator is de- termined ; b, a Liebig’s bulb filled with a solution of potash ; c, a U-tube filled with fragments of pumice moistened with S04H2; b and c are weighed together and their increase in weight is the weight of C02 in the volume of air operated on. Every gram of increase in weight represents 0.50607 litre, or 31.60356 cubic inches ; d is a tube of difficultly fusible glass, filled with black oxide of copper and heated to redness ; e is a U-tube filled with pumice moistened with SO,!!,; its increase in weight represents H20 obtained from decomposition of CH4. Every gram of increase in weight of OXIDES OF CARBON. 179 e represents 0.444 gram, or 0.621 litre, or 38.781 cubic inches of marsh gas ; f and g are similar to b and c, and their increase in weight represents C02 formed by oxidation of CO and CH, in d. From this the amount of CO is thus calculated : First, 2.75 grams are deducted from the increase of weight of / and g for each gram of CH4 formed by e ; of the remainder, every gram represents 0.6364 gram, or 0.5085 litre, or 31.755 cubic inches of CO. The air is drawn through the apparatus by opening the stopcock of A to such an extent that about 30 bubbles a minute pass through b. Fig. 36. Carbon disulphide—Bisulphide of carbon—Carbonei bisidphidum (II- S'.)—CS2—76—is formed by passing vapor of S over C heated to redness, and is partly purified by rectification. It is a colorless liquid ; when pure it has a peculiar, but not disagree- able odor, the nauseating odor of the commercial product being due to the presence of another sulphurated body; boils at 47° (116°.6 F.) ; sp. gr. 1.293 ; very volatile ; its rapid evaporation in vacuo produces a cold of — 60° ( —76° F.); it does not mix with H,0 ; it refracts light strongly. It is highly inflammable, and burns with a bluish flame, giving off C02 and S02 ; its vapor forms highly explosive mixtures wfith air, which deto- nate on contact with a glass rod heated to 250° (482° F.). Its vapor forms a mixture with nitrogen dioxide, which, when ignited, burns with a bril- liant flame, rich in actinic rays. There also exists a substance intermediate in composition between C02 and CS2, known as carbon oxysulphide, CSO, which is an inflammable, col- orless gas, obtained by decomposing potassium sulpliocyanate with dilute so4H2. Toxicology.—Cases of acute poisoning by CS2 have hitherto only been observed in animals ; its action is very similar to that of chloroform. Workmen engaged in the manufacture of CS2 and in the vulcanization of rubber, as well as others exposed to the vapor of the disulphide, are sub- ject to a form of chronic poisoning which may be divided into two stages. The first, or stage of excitation, is marked by headache, vertigo, a dis- agreeable taste, cramps in the legs ; the patient talks, laughs, sings, and weeps immoderately, and sometimes becomes violently delirious. In the 180 MANUAL OF CHEMISTRY. second stage the patient becomes sad and sleepy, sensibility diminishes, sometimes to the extent of complete anaesthesia, especially of the lower extremities, the headache becomes more intense, the appetite is greatly impaired, and there is general weakness of the limbs, which terminates in paralysis. The only remedy which has been suggested is thorough ventilation of the workshops, and abandonment of the trade at the first appearance of the symptoms. CHaOH Glyeollic acid— | —76—is formed by the oxidation of glycol, by COOH the action of nitrous acid on glycocol, and by the action of potash on mono- cliloracetic acid. It forms deliquescent, acicular crystals ; very soluble in water ; soluble in alcohol and ether ; has a strongly acid taste and reaction ; fuses at 78° (172°.4P.) ; is decomposed at 150° (302° F.) ; at an intermediate tem- perature it loses H..O, forming glycollide, or glyeollic anhydride, C2H2Oa. Lactic acids—C3Hf03—90.—There are probably three, certainly two acids having this composition. Two of these would seem, from their pro- ducts of decomposition, to be of similar constitution, while the molecular composition of the third is distinct; the two of similar constitution are sometimes designated as ethylidene lactic acids, because of their containing the group of atoms CH3, while the third is designated as ethyleno-lactic acid, as it contains the group CHa ; the constitution is expressed by the formulae : CH3 I CH,OH I COOH CHaOH I CH, I COOH Ethylidene lactic acid. Ethyleno-lactic acid. Obviously it is the ethylene acid which is the superior homologue of gly- collic acid. Ethyleno-lactic Acid.—Muscular tissue contains a mixture of this and optically active ethylidene lactic acid, which has been known as sarcolactic acid. Ethyleno-lactic acid may be obtained from muscular tissue or from Liebig’s extract of meat. 11 is optically inactive, as are also solutions of its salts ; its zinc salt contains 2 Aq, and is very soluble in water and quite soluble in alcohol. When oxidized by chromic acid it yields malonic acid. Of the two ethylidene lactic acids, that which is optically active is the one accompanying ethylene lactic acid, and predominating over it in amount, in dead muscle ; it is to this acid that the name paralactic acid is most properly applied. It may be obtained from Liebig’s meat extract. Paralactic acid differs from its two isomeres in that its solutions are dextrogyrous, and the solutions of its salts are lsevogyrous. The specific rotary power of the acid is [a]n= +3°.5; that of the zinc salt [a]D= — 7.6°; and of the calcium salt; [«]D= —3°.8. Its products of decomposi- tion are the same as those of ordinary lactic acid. Ordinary Lactic Acid—Lactic acid of fermentation—Optically inactive ethylidene lactic acid—Acidum lacticum (U. S.)—exists in nature, widely distributed in the vegetable kingdom, and as the product of a fermenta- OXIDES OF CAKBOX. 181 tion which is designated as the lactic, in milk, sour-krout, fermented beet- juice, and rice, and in the liquid refuse of starch factories and tanneries. Lactic acid is obtained as a product of the fermentation of certain sugars, milk-sugar and grape-sugar; as a result of the processes of nutri- tion of a minute vegetable, the lactic ferment, in which the sugar is con- verted into its polymere : CcH1206 = 2C3H603. It is usually produced by allowing a mixture of cane-sugar, tartaric acid, water, rotten cheese, skim milk and chalk to ferment for 10 days at 35° (95° F.). The calcium lactate produced is separated, purified and decomposed with an equivalent quantity of S04H2. It has also been obtained synthetically by oxidation of the propylglycol of Wurtz, which is a secondary glycol, a synthesis which indicates its con- stitution : ch3 ch3 I I CHOH + 03 = CHOH + H30 I I CHOH COOH Propylglycol. Oxygen. Lactic acid Water. It is a colorless, syrupy liquid ; sp. gr. 1.215 at 20° (68° F.); does not solidify at —24° ( —11°.2 F.); soluble in water, alcohol, and ether ; is not capable of distillation without decomposition; when heated to 130° (260° F.) it loses water and is converted into dilactic acid, CfH10O6, and, when heated to 250° (482° F.), into lactide, C3H404. It is a good solvent of tricalcic phosphate. Oxidizing agents convert this acid into formic and acetic acids, without the formation of any malonic acid. Physiological.—The three lactic acids occur in animal nature, either free or in combination. Free lactic acid of fermentation occurs in the contents of the small intestine, and, when vegetable food has been taken, in the stomach ; it is not, however, the acid to which the normal, unmixed gastric juice owes its acidity. Its salts have been found to exist in the contents of the stomach and those of the intestines, chyle, bile, parenchymatous fluid of spleen, liver, thymus, thyroid, pancreas, lungs, and brain ; urine. Pathologically in the blood in leucocythremia, pyae- mia, puerperal fever, and after excessive muscular effort; in the fluids of ovarian cysts and transudations. In the urine it is abundant in phos- phorus-poisoning, in acute atrophy of the liver, and in rachitis and osteo malachia. Muscular tissue, after death or continued contractions, contains the mixture of acids known to the older authors as sarcolactic acid. Normal, quiescent muscle is neutral in reaction ; but, when rigor mortis appears, or if the muscle be tetanized, its reaction becomes acid from the liberation of sarcolactic acid. Whether these acids are formed de novo during the contraction of the muscle, or whether they are produced by the decom- position of lactates existing in the quiescent muscle, is still undetermined; certain it is, however, that a given quantity of muscle has, when separated from the circulation, a fixed maximum of acid-producing capacity, which is greater in a muscle that has been tetanized during the interval between its removal and the establishment of rigor, than in one which has been at rest. There exist no grounds upon which to base the supposition that, in rheumatic fever, lactic acid is present in the blood. 182 MANUAL OF CHEMISTRY. DIATOMIC AND DIBASIC ACIDS. Series C„H2n_204. Oxalic acid C204H2 Malonic acid G304H4 Succinic acid C404H6 Deoxyglutanic acid C604H8 Adipic acid C6O4H10 Pimelic acid C704H12 Suberic acid C804H14 Azelaic acid C904Hle Sebacic acid C10O4H18 Roccellic acid C17041I32 They are derived from the primary glycols by complete oxidation ; they are diatomic and dibasic, and contain two groups, CO, OH. They form two series of salts with the univalent metals, and two series of ethers, one of which contains neutral, and the other acid ethers. They may be obtained from the corresponding glycols, or from acids of the pre- ceding series, by oxidation. COOH Oxalic acid— I —90—C204H2,2Aq—126—does not occur free COOH in nature, but in the oxalates of K, Na, Ca, Mg, and Fe in the juices of many plants, soi'rel, rhubarb, cinchona, oak, etc.; as a native ferrous oxa- late ; and in small quantity in human urine. It is prepared artificially by oxidizing sugar or starch by N03H, or by the action of an alkaline hydrate in fusion upon sawdust. The soluble alkaline oxalate obtained by the latter method is converted into the insoluble Ca or Pb salt, which is washed and decomposed by an equivalent quantity of S04H2 or H2S ; and the liberated acid purified by recrystallization. Oxalic acid is also formed by the oxidation of many organic substances —alcohol, glycol, sugar, etc.; by the action of potassa in fusion upon the alkaline formiates ; and by the action of K or Na upon CO„. It crystallizes in transparent prisms, containing 2Aq, which effloresce on exposure to air, and lose their Aq slowly but completely at 100° (212° F.), or in a dry vacuum. It fuses at 98° (208°.4 F.) in its Aq ; at 110°- 132° (230°-269°.6 F.) it sublimes in the anhydrous form, while a portion is decomposed ; above 1G0° (320° F.) the decomposition is more extensive ; H20, C02, CO, and formic acid are produced, while a portion of the acid is sublimed unchanged. It dissolves in 15.5 parts of water at 10° (50° F.); the presence of N03H increases its solubility. It is quite soluble in alcohol. It has a sharp taste and an acid reaction in solution. Oxalic acid is readily oxidized ; in watery solution it is converted into C02 and H„0, slowly by simple exposure to air, more rapidly in the pres- ence of platinum black or of the salts of platinum and gold ; under the influence of sunlight; or when heated with NOaH, manganese dioxide, chromic acid, Br, Cl, or hypochlorous acid. Its oxidation, when it is triturated dry with pure oxide of lead, is sufficiently active to heat the mass to redness. SO(H2, P04H3, and other dehydrating agents decompose it into H20, CO, and C02. Analytical Characters.—(1.) In neutral or alkaline solution a white ppt. with a solution of a Ca salt. (2.) Silver nitrate, a white ppt., soluble in N03H and in NH4HO. Tbe ppt. does not darken when the fluid is boiled, but, when dried and heated on platinum foil, it explodes. (3.) Lead acetate, in solutions not too dilute, a white ppt., soluble in NOsH, insoluble in acetic acid. 183 DIATOMIC AND DIBASIC ACIDS. Toxicology.—Although certain oxalates are constant constituents of vegetable food and of the human body, the acid itself, as well as hydro- potassic oxalate, is a violent poison when taken internally, acting both locally as a corrosive upon the tissues with which it comes in contact, and as a true poison, the predominance of either action depending upon the concentration of the solution. Dilute solutions may produce death without pain or vomiting, and after symptoms resembling those of narcotic poisoning. Death has followed a dose of 3 j- of the solid acid, and re- covery a dose of § j. in solution. When death occurs, it may be almost instantaneously, usually within half an hour ; sometimes after weeks or months, from secondary causes. The treatment, which must be as expeditious as possible, consists in the administration, first, of lime or magnesia, or a salt of Ca or Mg sus- pended or dissolved in a small quantity of or mucilaginous fluid ; afterward, if vomiting have not occurred spontaneously, and if the symptoms of corrosion have not been severe, an emetic may be given. In the treatment of this form of poisoning several points of negative cau- tion are to be observed. As in all cases in which a corrosive has been taken internally, the use of the stomach-pump is to be avoided. The al- kaline carbonates are of no value in cases of oxalic acid poisoning, as the oxalates which they form are soluble, and almost as poisonous as the acid itself. The ingestion of water, or the administration of warm water as an emetic, is contraindicated when the poison has been taken in the solid form (or where doubt exists as to what form it was taken in), as they dis- solve, and thus favor the absorption of the poison. Analysis.—In fatal cases of poisoning by oxalic acid the contents of the stomach are sometimes strongly acid in reaction ; more usually, owing to the administration of antidotes, neutral, or even alkaline. In a sys- tematic analysis the poison is to be sought for in the residue of the por- tion examined for prussic acid and phosphorus ; or, if the examination for those substances be omitted, in the residue or final alkaline fluid of the process for alkaloids (see p. 252 et seq.). If oxalic acid alone is to be sought for, the contents of the stomach, or other substances if acid, are extracted with water, the liquid filtered, the filtrate evaporated, the residue extracted with alcohol, the alcoholic fluid evaporated, the residue redissolved in water (solution No. 1). The portion undissolved by al- cohol is extracted with alcohol acidulated with hydrochloric acid, the solution evaporated after filtration, the residue dissolved in water (so- lution No. 2). Solution No. 1 contains any oxalic acid which may have existed free in the substances examined ; No. 2 that which existed in the form of soluble oxalates. If lime or magnesia have been administered as an antidote, the substances must be boiled for an hour or two with potas- sium carbonate (not the hydrate), filtered, and the filtrate treated as above. In the solutions so obtained, oxalic acid is characterized by the tests given above. The urine is also to be examined microscopically for crystals of cal- cium oxalate. The stomach may contain small quantities of oxalates as normal constituents of certain foods. CH—COOH Malonic acid— | —104—is a product of oxidation of COOH ethyleno-lactic acid, and is identical with the nicotic acid of tobacco. It forms prismatic crystals, very soluble in H O, alcohol, and ether ; which fuse at 140° (284° F.), and are decomposed at 150° (302° F.). 184 MANUAL OF CHEMISTRY. CH—COOH Succinic acid— | —118—exists in amber, coal, fossil wood, CH— COOH and in small quantity in animal and vegetable tissues. Its presence bas been detected in the normal urine after the use of fruits and of asparagus, in the parenchymatous fluids of the spleen, thyroid, and thymus, and in the fluids of hydrocele and of hydatid cysts. It is also formed in small quan- tity during alcoholic fermentation ; as a product of oxidation of many fats and fatty acids ; and by synthesis from ethylene cyanide. It may be obtained by dry distillation of amber, or, preferably, by the fermentation of malic acid. It crystallizes in large prisms or hexagonal plates, which are colorless, odorless, permanent in air, acid in taste, soluble in water, sparingly so in ether and in cold alcohol. It fuses at 180° (356° F.), and distils with par- tial decomposition at 235° (455° F.). It withstands the action of oxidiz- ing agents ; reducing agents convert it into the corresponding acid of the fatty series, butyric acid ; with Br it forms products of substitution ; S04H2 is without action upon it; phosphoric anhydride removes HaO and converts it into succinic anhydride, C4H403. COMPOUND ETHERS OF THE ACIDS OF THE SERIES C„H2„03 and C„H2n_a04. The members of both of these series contain two atoms of H replace- able by alcoholic radicals. In those of the series C„H2„03 (with the exception of carbonic acid), being monobasic, although diatomatic, it is not immaterial which H is so replaced. If it be that of the group CH2OH, the resulting compound is a monobasic acid, in which the H of the group COOH may be replaced by another alcoholic radical to form a neutral ether of the new acid ; if, on the other hand, the H of the group COOH be first replaced, a neutral compound ether is formed. In the members of the series C„H„n_a04, which are dibasic, the substitution of an alco- holic radical for the H of either group COOH produces a monobasic acid, in which the H of the other COOH may be replaced by another radical to form a neutral ether. The following formulae indicate the differences in the nature of these compounds : ch2oh I COOH CH2OC2H5 I COOH CH„OH I COOC2H5 ch,oc2h& I COOC2H5 Glycolic acid. Ethylglycolic acid. Ethyl glycolate. Ethyl ethylglycolate. COOC2H5 COOH COOH I COOH cooc„h5 I COOC2H6 Oxalic acid. Ethyloxalic acid. Ethyl oxalate. AMINES OF THE GLYCOLS. 185 ALDEHYDES AND ANHYDRIDES OF THE SERIES C„HanOs and C„Ha„_a04. In treating of the monoatomic compounds, it was stated that sub- stances existed corresponding to the fatty acids, known as aldehydes and anhydrides, the former differing from the acids in that they contained the group COH instead of COOH ; the latter being the oxides of the acid radicals. Similar compounds exist corresponding to the acids of these two series. The aldehydes corresponding to the series CnHaJl03 contain the group COH in place of the group COOH, and as they also contain the group C1IV0H, they are possessed of the double function of primary alcohol and aldehyde. Those of the series CBHJt*_a04 form two series ; in one of which only one of the groups COOH is deoxidized to COH ; in the other, both. Those of the first series, still containing a group COOH, are monobasic acids as well as aldehydes : ch3oh I COOH CH..OH COH COOH I COOH COOH I COH COH I COH Glycolic acid. Glycolic aldehyde. Oxalic acid. Glyoxalic acid. GlyoxoL While the anhydrides of the fatty series may be considered as derived from the acids by the subtraction of H20 from two molecules of the acid ; those of both the series of acids under consideration are derived from a single molecule of the acid by the subtractioD of H_,0 : CH3 I COOH CH2OH I COOH CH—COOH I CH—COOH Acetic acid. Glycolic acid. Succinic acid. ch—cox >° CH—CO/ CH I >0 CO / CH3—CO. 1 /° CH—CO/ Acetic anhydride. Glycolic anhydride. Succinic anhydride. AMINES OF THE GLYCOLS. Ethylenic Compound Ammonias. These substances are derived from a double molecule of NH3, or of ammonium hydrate, by the substitution of the diatomic radicals of the glycols (hydrocarbons of the series C„Hon) for an equivalent number of H atoms. They are distinguished from the corresponding compounds of the radicals of the monoatomic alcohols, the monamines, by the designation of diamines. When it is considered that in the formation of these substances double 186 MANUAL OF CHEMISTRY. H atoms can be replaced by diatomic radicals to form primary, secondary, and tertiary amines: HJ Hj-Na HJ (CaH4)") HjN, Hj (CTO") (CTO"U hJ < 1.1334 1.1365 1.1396 1.1427 1.1458 1.1489 1.1520 1.1551 1.1582 1.1613 1.1644 1.1675 1.1706 18" S’ 1.1279 1.1310 1.1341 1.1372 1.1403 1.1434 1.1465 1.1496 1.1527 1.1558 1.1589 1.1620 1.1650 19“ o 1.1225 1.1256 1.1287 1.1318 1.1348 1.1379 1.1410 1.1441 1.1472 1.1502 1.1533 1.1504 1.1595 20“ 3 1.1170 1.1201 1.1231 1.1262 1.1293 1.1324 1.1354 1.1385 1.1416 1.1446 1.1477 1.1508 1.1539 21“ 1.1115 1.1145 1.1176 1.1206 1.1237 1 1263 1.1298 1.1329 1.1359 1.1390 1.1421 1.1451 1.1482 22° (g 1.1058 1.1089 1.1119 1.1150 1.1180 1.1211 1.1211 1.1272 1.1302 1.1333 1.1363 1.1394 1.1424 23“ Cu 1.1001 1.1032 1,1063 1.1092 1.1123 1 .1153 1.1184 1.1214 1.1214 1.1275 1.1305 1.1336 1.1366 24“ 1.0944 1.0974 1.1004 1.1035 1.1065 1.1095 1.1126 1 1156 1.1186 1.1216 1 1247 1.1277 1.1307 25“ J 746 748 750 752 754 756 758 760 762 764 766 768 770 Barometric pressure in millimetres. liq. sod. chlor., and, after the first violence of the reaction has subsided, the mixture is shaken from time to time during an hour, when the decomposition is complete ; the sp. gr. of the mixture is then determined. As the reaction begins instantaneously when the urine and reagent are mixed, the sp. gr. of the mixture must be calculated by adding together once the sp. gr. of the urine and seven times the sp. gr. of the liq. sod. chlor., and dividing the sum by eight. From the quotient so obtained the sp. gr. of the mixture after decomposition is subtracted ; every degree of loss in sp. gr. indicates 0.7791 gram of urea in 100 c.c. of urine. The sp. gr. determinations must all be made at the same temperature; and that of the mixture only when the evolution of gas has ceased entirely. Finally, when it is only desired to determine whether the urea is greatly in excess or much below the normal, advantage may be taken of the formation of crystals of urea nitrate. Two samples of the urine are taken, one of 5 c.c. and one of 10 c.c. ; the latter is evaporated, at a low temperature, to the bulk of the former, and cooled; to both one-third volume of colorless N03H is added. If crystals do not form within a few moments in the concentrated sample, the quantity of urea is below the normal; if they do in the unconcentrated sample, it is in excess. In using this very rough method, regard must be had to the quantity of urine passed in 24 hours ; the above applies to the normal amount of 1200 c.c. ; if the quantity be greater or less, the urine must be concentrated or diluted in proportion. This method cannot be used if the urine is albuminous. Compound Ureas. These compounds, which are exceedingly numerous, may be considered as formed by the substitution of one or more alcoholic or acid radicals for one or more of the remaining H atoms of urea. Those containing alcoholic radicals may be obtained, as urea is ob- tained from ammonium cyanate, from the cyanate of the corresponding compound ammonium ; or by the action of NH3, or of the compound ammonias, upon the cyanic ethers. Those containing acid radicals have received the distinctive name of ureids ; some of them are derivatives of uric acid, which is itself probably 196 MANUAL OF CHEMISTRY. an ureid. We will limit our consideration of these bodies to uric acid and the ureids obtained from and related to it. Uric acid—Lithic acid— Cs.H,N403H2—1G8.—Occurrence.—So far as jet known, uric acid is exclusively an animal product. It exists in the urine of man and of the carnivora, and in that of the herbivora when, during early life or starvation, they are for the time being carnivora ; as a constituent of urinary calculi ; and very abundantly in the excrement of serpents, tortoises, birds, molluscs, and insects, also in guano. It is pres- ent in very small quantity in the blood of man, more abundantly in that of gouty patients and in that of birds. The so called “chalk-stones” de- posited in the joints of gouty patients are composed of sodium urate. It also occurs in the spleen, lungs, liver, pancreas, brain, and muscular fluid. Preparation.—-Although uric acid may be obtained from calculi, urine, and guano, the source from which it is most readily obtained in a state of purity is the solid urine of large serpents, which is composed almost entirely of uric acid and the acid urates of sodium, potassium, and am- monium. This is dried, powdered, and dissolved in a solution of potassium hydrate, containing one part of potash to 20 of water; the solution is boiled until all odor of NH3 has disappeared. Through the filtered solu- tion C02 is passed, through a wide tube, until the precipitate, which was at first gelatinous, has become granular and sinks to the bottom ; the acid potassium urate so formed is collected on a filter, and washed with cold H20 until the wash-water becomes turbid when added to the first filtrate ; the deposit is now dissolved in hot dilute caustic potassa solution, and the solution filtered hot into HC1, diluted with an equal volume of H.,0. The precipitated uric acid is washed and dried. Properties—Physical.—Uric acid, when pure, crystallizes in small, white, rhombic, rectangular or hexagonal plates, or in rectangular prisms, or in dendritic crystals of a hydrate, CtH4N403,2H.,0. As crystallized from urine it is more or less colored with urinary pigments, and forms rectangular or rhombic plates, usually with the angles rounded so as to form lozenges, which are arranged in bundles, daggers, crosses, or den- dritic groups, sometimes of considerable size. It is almost insoluble in H.20, requiring for its solution 1900 parts of boiling H,,0 and 15,000 parts of cold H.20 ; insoluble in alcohol and ether ; its aqueous solution is acid to test-paper ; cold HC1 dissolves it more readily than H O, and on evapo- ration deposits it in rectangular plates. It is tasteless and odorless. Chemical —When heated, it is decomposed without fusion or sublima- tion. Its constitution is unknown. Heated in Cl it yields cyan uric acid and HC1. When Cl is passed for some time through H;0 holding uric acid in suspension, alloxan, parabanic and oxalic acids, and ammonium cyanate are formed. Similar decomposition is produced by Br and I. It is simply dissolved by HC1. It is dissolved by S04H, ; from a hot solu- tion in which a deliquescent, crystalline compound, C5H4N40,, 4S04H, is deposited; it is partly decomposed by SO H2 at 140° (284° F.). It dis- solves in cold NO. H with effervescence and formation of alloxan, alloxan- tine, and urea ; with hot NO,,H parabanic acid is produced. Solutions of the alkalies dissolve uric acid with formation of neutral urates. Uric acid is dibasic. Ammonium urates.—The neutral salt, C.H.,N4Oa(NH4)„, is unknown. The acid salt, C.H,!N4Os(NH1), exists as a constituent of the urine of the lower animals, and occurs, accompanying other urates and free uric acid, in urinary sediments and calculi. Sediments of this salt are rust-yellow or pink in color, amorphous, or composed of globular masses, set with pro- COMPOUND UREAS. jecting points, or elongated dumb-bells, and are formed in alkaline urine. It is very sparingly soluble in H,,0 ; soluble in warm HC1, from which solution crystalline plates of uric acid are deposited. Potassium urates.—The neutral salt, C6H2N4OsK3, is obtained when a solution of potassium hydrate, free from carbonate, is saturated with uric acid ; the solution on concentration deposits the salt in fine needles. It is soluble in 44 parts of cold H30 and in 35 parts of boiling H30. It is alkaline in taste, and absorbs CO,, from the air. The acid salt, C.H.N403K, is formed as a granular (at first gelatinous) precipitate when a solution of the neutral salt is treated with C03. It dissolves in 800 parts of cold H20 and in 80 parts of boiling H,,0. The occurrence of potassium urates in urinary sediments and calculi is very exceptional. /Sodium urates.—The neutral salt, C5H3N403Na3, is formed under simi- lar conditions as the corresponding potassium salt. It forms nodular masses, soluble in 77 parts of cold H30 and in 75 of boiling H30 ; it absorbs C03 from the air. The acid salt, C5H3N403Na, is formed when the neutral salt is treated with C02. It is soluble in 1200 parts of cold H.,0 and in 125 parts of boiling I120. It occurs in urinary sediments and calculi, very rarely crys- tallized. The arthritic calculi of gouty patients are almost exclusively composed of this salt, frequently beautifully crystallized. Calcium urates.—The neutral salt, C6H2N403Ca, is obtained by-drop- ping a solution of neutral potassium urate into a boiling solution of cal- cium chloride until the precipitate is no longer redissolved, and then boil- ing for an hour. A granular powder, soluble in 1500 parts of cold H30 and in 1440 parts of boiling H30. The acid salt, (C5H3N403)3Ca, is obtained by decomposing a boiling solution of acid potassium urate with calcium chloride solution. It crys- tallizes in needles, soluble in 603 parts of cold H30 and in 276 parts of boiling H30. It occurs occasionally in urinary sediments and calculi, and in “chalk-stones.” Lithium urates.—The acid salt, CrH3N403Li, is formed by dissolving uric acid in a warm solution of lithium carbonate. It crystallizes in needles, which dissolve in 60 parts of H30 at 50° (122° F.) and do not separate when the solution is cooled. It is with a view to the formation of this, the most soluble of the acid urates, that the compounds of lithium are given to patients suffering with the uric acid diathesis. Physiology.—Uric acid exists in the economy chiefly in combination as its sodium salts ; it is occasionally found free, and from the probable method of its formation it is difficult to understand how all the uric acid in the economy should not have existed there free, at least at the instant of its formation. It can scarcely be doubted that uric acid is one of the products of the oxidation of the albuminoid substances—an oxidation in- termediate in the production of urea ; and that consequently diseases in which there is an excessive formation of uric acid, such as gout, have their origin in defective oxidation. In human urine the quantity of uric acid varies with the nature of the food in the same manner as does urea, and in about the same pro- portion : Urea. Uric acid. Proportion of uric acid to urea. Animal food 71.5 1.25 0.76 57.2 48.7 Vegetable food Non-nitrogenized food 26.0 0.50 0.34 52.0 47.0 198 MANUAL OF CHEMISTRY. The mean elimination of uric acid in the urine is from one-thirty-fifth to one-sixtieth of that of urea, or about 0.5 to 1.0 gram (7.7-15.4 grains) in 24 hours. With a strictly vegetable diet the elimination of 24 hours may fall to 0.3 gram (4.6 grains), and with a surfeit of animal food it may rise to 1.5 gram (23 grains). The hourly elimination is increased after meals, and diminished by fasting and by muscular and mental activity. Deposits of free uric acid occur in acid, concentrated urines. In gout the proportion of uric acid in the urine is diminished, although, owing to the small quantity of urine passed, it may be relatively great; during the paroxysms the quantity of uric acid is increased, both relatively and absolutely. The proportion of uric acid in the blood is invariably in- creased in gout. Analytical Chakactebs.—Uric acid may be recognized by its crystalline form and by the murexid test. To apply this test the substance is moistened with NO;iH, which is evaporated nearly to dryness at a low temperature ; the cooled residue is then moistened with ammonium hydrate. If uric acid be present, a yellow residue—sometimes pink or red when the uric acid was abundant—remains after the evaporation of the N03H, and this, on the addition of the alkali, assumes a rich purplish-red color. To detect uric acid in the blood, about two drachms of the serum are placed in a flat glass dish and faintly acidulated with acetic acid ; a very fine fibril of linen thread is placed in the liquid, which is set aside and allowed to evaporate to the consistency of a jelly ; the fibril is then removed and examined microscopically. If the blood contain uric acid in abnormal proportion, the thread will have attached to it crystals of uric acid. Quantitative Determination.—The best method for the determination of the quantity of uric acid in urine is the following: 250 c.c. of the fil- tered urine are acidulated with 10 c.c. of HC1, and the mixture set aside for 24 hours in a cool place. A small filter is washed, first with dilute HC1 and then with H„0, dried at 100° (212° F.), and weighed. At the end of 24 hours this filter is moistened in a funnel, and the crystals of uric acid collected upon it (those which adhere to the walls of the precipitating vessel are best separated by a small section of rubber tubing passed over the end of a glass rod, and used as a brush). No H,20 is to be used in this part of the process, the filtered urine being passed through a second time, if this be required, to bring all the crystals upon the filter. The deposit on the filter is now washed with 35 c.c. of pure H20, added in small portions at a time ; the filter and its contents are then dried and weighed. The difference between this weight and that of the dry filter alone is the weight of uric acid in 250 c.c. of urine. If from any cause more than 35 c.c of wash-water have been used, 0mgr-.043 must be added to this weight for every c.c. of extra wash-water. If the urine contain albumen, this must first be separated by adding two or three drops of acetic acid, heating to near 100° (212° F.), until the coagulum becomes flocculent, and filtering. Ureids derived from Uric Acid.—These substances are quite numer- ous, and are divisible into ureids, diureids, triureids, and urasmic acids, ac- cording as they are formed by substitution in one, two, or three molecules of urea, and according as the acid radical substituted does or does not re- tain a group COOH. Some of these substances require a brief mention : (CO)" ) Oxalylurea—Parabanic acid— (CA)" N, —114 —is urea in which A ) two atoms of H have been replaced by the bivalent radical (CA) > of SUBSTANCES OF UNKNOWN CONSTITUTION. 199 oxalic acid. It is obtained by oxidizing uric acid or alloxan by hot no3h. AUantoxn — C4H6N203—130 — occurs in the allantonic fluid of the cow ; in the urine of sucking calves, in that of dogs and cats when fed on meat, in that of children during the first eight days of life, in that of adults after the ingestion of tannin, and in that of pregnant women. It is produced artificially by oxidizing uric acid, suspended in boiling II20, with lead dioxide. It crystallizes in small, tasteless, neutral, colorless prisms ; sparingly soluble in cold H20, readily soluble in warm H20. Heated with alkalies it yields oxalic acid and NH3 ; and with dilute acids, allanturic acid, c3h4n2o3. Mesoxalylurea—Alloxan—C4H2N204—142—is a product of the limited oxidation of uric acid. It has been found in the intestinal mucus in a case of diari'hoea. It forms colorless crystals, readily soluble in II20. It gradually turns red in air, and stains the skin red. Oxaluric Acid—C3H4N„04—132—occurs in its ammonium salt, as a normal constituent, in small quantity, in human urine. It may be ob- tained by heating oxalylurea with calcium carbonate. It is a white, sparingly soluble powder, which is converted into urea and oxalic acid when boiled with water or alkalies. Its ammonium salt crystallizes in white, glistening, sparingly soluble needles. Its ready conversion into urea and oxalic acid and its formation from oxalylurea, it- self a product of oxidation of uric acid, render it probable that oxaluric acid is one of the many intermediate products of the oxidation of the ni- trogenous constituents of the body. Substances of Unknown Constitution Related to Uric Acid. Xanthine—Xanthic oxide—Urous acid—C5H4N40„—152—occurs in a rare form of urinary calculus ; in tlie pancreas, spleen, liver, thymus, and brain of mammals and fishes; and in human urine after the use of sulphur baths or inunctions. It is an amorphous, yellowish-white powder; very slightly soluble in cold H20. If dissolved in N03H and the solution evaporated, xanthine leaves a yellowish residue, which turns reddish-yellow on the addition of potash solution, and violet-red when heated. Xanthine calculi vary in size from that of a pea to that of a pigeon’s egg. They are rather hard, brownish-yellow, smooth, shining, and made up of well-defined, concentric layers. Their broken surfaces assume a waxy polish when rubbed. Hypoxanthine—Sarcine—C.HNO—136—occurs in the spleen, muscular tissue, thymus, suprarenal capsules and brain of mammals ; in the liver in acute yellow atrophy ; and in the blood and urine in leucocy- thaemia. It may be obtained from the mother liquor of the preparation of creatine (q. v.). It forms nodular masses ; soluble in 300 parts of cold, and 78 parts of boiling II20. It is produced from uric acid or from xanthine by the action of sodium amalgam, and when oxidized by N03H it yields xanthine. Guanine—C6H5N&0—151—occurs in guano, in the excrements of the lower animals, and in the pancreas, lungs, and liver of certain mam- malians. It is a white or yellowish, amorphous, odorless and tasteless 200 MANUAL OF CHEMISTRY. solid; almost insoluble in H20, alcohol and ether ; readily soluble in acids and alkalies, with which it forms compounds. Carnine—C7HflN403 + H20—196 + 18—is obtained from Liebig’s meat extract in chalky, microscopic crystals, readily soluble in warm li20. It forms compounds with acids and alkalies, similar to those of liypoxan- thine. TRIATOMIC ALCOHOLS. Series C„H2n+203. There is as yet only one alcohol known containing a trivalent radical. This is glycerin, whose relation to the monoatomic and diatomic alcohols is shown by the following formulas : ch3 I ch2 I CH3 ch3 ch2 ch2oh CH..OH I ch2 ch2oh CH2OH I CITOH I ch2oh Propane. Propyl alcohol. Propyl glycol. Glycerin. Glycerin—Glycerinum (U. S.)—C5Hs(OH)3—92—was first obtained as a secondary product in the manufacture of lead plaster ; it is now pro- duced as a by-product in the manufacture of soaps and of stearin candles. It exists free in palm-oil and in other vegetable oils ; it is produced in small quantity during alcoholic fermentation, and is consequently present in wine and beer. It is much more widely disseminated in its ethers, the neutral fats, in the animal and vegetable kingdoms. It has been obtained by partial synthesis, by heating for some time a mixture of allyl tribromide, silver acetate and acetic acid, and saponifying the triacetin so obtained. The glycerin obtained by the process now generally followed—the decomposition of the neutral fats and distillation of the product in a cur- rent of superheated steam—is free from the impurities which contami- nated the product of the older processes. The only impurity likely to be present is water, which may be recognized by the low sp. gr. Glycerin is a colorless, odorless, syrupy liquid ; has a sweetish taste ; sp. gr. 1.26 at 15° (59° F.). Although it cannot usually be caused to crystallize by the application of the most intense cold, it does so some- times under imperfectly understood conditions, forming small white needles of sp. gr. 1.268, and fusible between 7 J and 8° (44°.6-46°.4 F.) ; it is soluble in all proportions in water and alcohol, insoluble in ether and in chloroform. The sp. gr. of mixtures of glycerin and water increase with the proportion of glycerin. It is a good solvent for a number of mineral and organic substances (glycerites and glyceroles). It is not volatile at ordinary temperatures. When heated, a portion distils unaltered at 275°- 280° (527°-536° F.), but the greater part is decomposed into acrolein, acetic acid, carbon dioxide and combustible gases. It may be distilled unchanged in a current of superheated steam between 285° and 315° (545°-599° F.). Platinum black oxidizes glycerin with the production, finally, of H20 and COa; oxidized by manganese dioxide and S04H2, it yields C02 and ETHERS OF GLYCERIN. 201 formic acid. If a layer of glycerin, dilated with H20, be floated on N03H of sp. gr. 1.5, glyceric acid is formed. By the action of a mixture of N03H and S04H, on glycerin, nitroglycerin is formed. When glycerin is heated with an alkaline hydrate, a mixture of potassium acetate and formiate is produced. The elements of H.20 are removed from glycerin, with for- mation of acrolein (q. v.), by P205; or by heating with S04H2, or with potassium hydrosulphate. Heated with oxalic acid it yields C02 and formic acid. The glycerin used for medicinal purposes should respond to the fol- lowing tests : (1) its sp. gr. should not vary much from that given above ; (2) it should not rotate polarized light; (3) it should not turn brown when heated with sodium hydrate ; (4) it should not be colored by H2S ; (5) when dissolved in its own weight of alcohol, containing one per cent, of S02H4, the solution should be clear; (6) when mixed with an equal volume S04H.,, of sp. gr. 1.83, it should form a limpid, brownish mixture, but should not give off gas. ACIDS DERIVABLE FROM THE GLYCERINS. Two series of acids are derivable from the glycerins by substitution of 0 for H2 in the group CH .OH : CH20H I CHOH I CH„OH ch2oh I CHOH COOH COOH I CHOH I COOH Glycerin. Glyceric acid. Tartronic acid. The terms of both series are triatomic ; those of the glyceric series are monobasic, and those of the tartronic series are dibasic (see p. 167). Malic acid—C H60—134 —is the second term of the tartronic series, and is therefor dibasic. It exists in the vegetable kingdom ; either free or combined with K, Na, Ca, Mg, or organic bases ; principally in fruits, such as apples, cherries, etc. ; accompanied by citrates and tartrates. It crystallizes in brilliant, prismatic needles ; odorless ; acid in taste ; fusible at 100° (212° F.); loses H,0 at 140° (284° F.) ; deliquescent; very soluble in H20 and in alcohol. Heated to 175°-180° (347°-356° F.), it is decomposed into HO and maleic acid, C4H404. The malates are oxidized to carbonates in the body. ETHERS OF GLYCERIN. Glycerides. Being a triatomic alcohol, glycerin contains three groups OH, the H of each of which may be replaced by an acid radical; or, more properly speaking, one, two, or three of these oxhydryl groups may be removed, leaving a univalent, bivalent, or trivalent remainder, which may replace 202 MANUAL OF CHEMISTRY. the H of one, two, or three molecules of a monobasic acid to form three series of ethers : cii2oh CHOH I CH3OH CH-O-Cpp I CHOH I ch2oh CH —O—C H O | CH—O—C2H30 ch2oh CH—O—C,,HO I CH—O—C2H30 i CH—O—C2H30 Glycerin. Manoacetin. Diacetin. Triacetin. Of the many substances of this class, only a few, principally those en- tering into the composition of the neutral fats, require consideration here. Tributyrin—C3H5 (0,C4H70)3 —302—exists in butter. It may also be obtained by heating glycerin with butyric acid and S04H2. It is a pungent liquid, very prone to decomposition, with liberation of butyric acid. Trivalerin—C3H5 (O,CH0O) 3—344—exists in the oil of some mari- time mammalia, and is identical with the phocenine of Chevreul. Tricaproin — C3H5 (0,CcHii0)3 —386 — Tricaprylin C3H (0,C8 h16o), —470—and Tricaprin—C;)Hr (O,C10H19O)3 —554—exist in small quantities in milk, butter, and cocoa-butter. Tripalmitin—C3HS (0,C,6H310)- -806—exists in most animal and vegetable fats, notably in palm-oil; it may also be obtained by heating glycerin with 8 to 10 times its weight of palmitic acid for 8 hours at 250° (482° F.). It forms crystalline plates, very sparingly soluble in alcohol, even when boiling ; very soluble in ether. It fuses at 50° (122° F.) and solidifies again at 46° (114°.8 F.). Trimargarin—C,H6 (0,C17H330)3- -848—has probably been obtained artificially as a crystalline solid, fusible at 60° (140° F.), solidifiable at 52° (125°.6 F.). The substance formerly described under this name as a con- stituent of animal fats is a mixture of tripalmitin and tristearin. Tristearin—C3H6 (0,C18H350)3—890—is the most abundant constit- uent of the solid fatty substances. It is prepared in large quantities as an industrial product in the manufacture of stearin candles, etc., but is ob- tained in a state of purity only wTith great difficulty. In as pure a form as readily obtainable, it forms a hard, brittle, crystal- line mass ; fusible at 68° (154°.4 F.), solidifiable at 61° (141°.8 F.) ; soluble in boiling alcohol, almost insoluble in cold alcohol, readily soluble in ether. Triolein-C3H6 (0,C18H330)3 —884—exists in varying quantity in all fats, and is the predominant constituent of those which are liquid at ordi- nary temperatures; it may be obtained from animal fats by boiling with alcohol, filtering the solution, decanting after twenty-four hours’ standing ; freezing at 0° (32° F.), and expressing. It is a colorless, odorless, tasteless oil; soluble in alcohol and ether, insoluble in water ; sp. gr. 0.92. Trinitro-glycerin—Nitro-glycerin — C3HB (ONO,,)3—227—used as an explosive, both pure and mixed with other substances, in dynamite, giant powder, etc., is obtained by the combined action of S04H2 and NOsH upon glycerin. Fuming NO.H is mixed with twice its weight of S04H„ in a cooled earthen vessel; 33 parts by weight of the mixed acids are placed in a porcelain vessel, and 5 parts of glycerin, of 31° Beaum6, are gradually added with constant stirring, while the vessel is kept well cooled ; after five minutes the whole is thrown into 5-6 volumes of cold NEUTRAL OILS AND FATS. 203 water; the nitro-glycerin separates as a heavy oil which is washed with cold water. Nitro-glycerin is an odorless, yellowish oil; has a sweetish taste ; sp. gi*. 1.6 ; insoluble in water, soluble in alcohol and ether ; not volatile ; crystallizes in prismatic needles when kept for some time at 0° (32° F.); fuses again at 8° (46°.4 F.). When pure nitro-glycerin is exposed to the air at 30° (86° F.) for some time, it decomposes, without explosion and with production of glyceric and oxalic acids. When heated to 100° (212° F.) it volatilizes without de- composition ; at 185° (365° F.) it boils, giving off nitrous fumes ; at 217° (422°. 6 F.) it explodes violently ; if quickly heated to 257° (494°.6 F.) it assumes the spheroidal form, and volatilizes without explosion. Upon the approach of flame at low temperatures it ignites and burns with slight decrepitations. When subjected to shock, it is suddenly decomposed into CO^; N ; vapor of H20, and O, the decomposition being attended with a violent explosion. In order to render this explosive less dangerous to handle, it is now usually mixed with some inert substance, usually diatomaceous earth, in which form it is known as dynamite, etc. When taken internally, nitro-glycerin is an active poison, producing effects somewhat similar to those of strychnine ; in drop-doses, diluted, it causes violent headache, fever, intestinal pain, and nervous symptoms. It has been latterly used as a therapeutic agent, and has been used by the homoeopaths under the name of glonoin. NEUTRAL OILS AND FATS. These are mixtures in varying proportions of tripalmitin, tristearin, and triolein, with small quantities of other glycerides, coloring and odor- ous principles, which are obtained from animal and vegetable bodies. The oils are fluid at ordinary temperatures, the solid glycerides being in solution in an excess of the liquid triolein. The fats, owing to a less pro- portion of the liquid glyceride, are solid or semi-solid at the ordinary tem- perature of the air. Members of both classes are fluid at sufficiently high temperatures, and solidify when exposed to a sufficiently low temperature. They are, when pure, nearly tasteless and odorless, unctuous to the touch, insoluble in and not miscible with H O, upon which they float; combus- tible, burning with a luminous flame ; when rubbed upon paper they ren- der it translucent. When heated with the caustic alkalies or in a current of superheated steam, they are saponified, i.e., decomposed into glycerin and a fatty acid. If the saponification be produced by an alkali, the fatty acid combines with the alkaline metal to form a soap (q. v.). Most of the fats and many of the oils, when exposed to the air, absorb 0, are decomposed with liberation of volatile fatty acids, and acquire an acid taste and odor, and an acid reaction. A fat which has undergone these changes is said to have become rancid. Many of the vegetable oils are, however, not prone to this decomposition. Some of them, by oxida* tion on contact with the air, become thick, hard and dry, forming a kind of varnish over surfaces upon which they are spread ; these are as drying or siccative oils. Others, although they become more dense on exposure to air, become neither dry nor gummy ; these are known as non. drying, greasy, or lubricating oils. Under ordinary conditions, oils and melted fats do not mix with 204 MANUAL OF CHEMISTRY. water, and, if shaken with that fluid, form a temporary milky mixture, which, on standing for a short time, separates into two distinct layers, the oil floating on the water. In the presence, however, of small quantities of certain substances, such as albumen, pancreatin (q. v.), ptyalin, etc., the milky mixture obtained by shaking together oil and water does not sepa- rate into distinct layers on standing; such a mixture, in which the fat is held in a permanent state of suspension in small globules in a watery fluid, is called an emulsion. Perfect emulsions may be easily obtained by agitating an oil containing a trace of free oleic acid with a very dilute solution of sodium carbonate and borax. Fixed oils.—These substances are designated as “fixed,” to distinguish them from other vegetable products having an oily appearance, but which differ from the true oils in their chemical composition and in their physical properties, especially in that they are volatile without decomposition, and are obtained by distillation, while the fixed oils are obtained by expression, with or without the aid of a gentle heat. Palm oil is a reddish-yellow solid at ordinary temperatures, has a bland taste and an aromatic odor. It saponifies readily, and is usually acid and contains free glycerin from spontaneous decomposition. Pape seed and colza oils, produced from various species of Brassica, are yellow, limpid oils having a strong odor and disagreeable taste. Croton-oil—Oleum tiglii (U. S.)—Oleum crotonis (Br.)—varies much in color and activity, according to its source ; that which is obtained from the East is yellowish, liquid, transparent, and much less active than that prepared in Europe from the imported seeds, which is darker, less fluid, caustic in taste, and wholly soluble in absolute alcohol. Croton-oil con- tains, beside the glycerides of oleic, crotonic and fatty acids, about four per cent, of a peculiar principle called crotonol, to which the oil owes its vesicating properties ; it also contains an alkaloid-like substance, also ex- isting in castor-oil, called ricinine. None of these bodies, however, are possessed of the drastic powers of the oil itself. Peanut-oil—Ground-nut oil—an almost colorless oil, very much re- sembling olive-oil, in place of which it is frequently used for culinary purposes, intentionally or otherwise. It is readily saponifiable, yielding two peculiar acids, arachaic and hypogaic (see Olive-oil). Cotton-seed oil—Oleum gossypii seminis (U. S.)—a pale yellow, bland oil, also resembling olive-oil, for which it is frequently substituted. Almond-oil—Oleum amygdalae ecrpressum (U. S.)—Oleum amygdalae (Br.)—a light yellow oil, very soluble in ether, soluble in alcohol; nearly inodorous ; has a bland, sweetish taste. The pure oil has no odor of bitter almonds. Olive-oil—Oleum olivae (U. S., Br.).—A well-known oil of a yellow or greenish-yellow color, almost odorless, and of a bland and sweetish taste. The finest grades have a yellow tinge and a faint taste of the fruit; they are prepared by cold pressure ; they are less subject to rancidity than the lower grades. Olive-oil is very frequently adulterated, chiefly with poppy- oil, sesame oil, cotton-seed oil and peanut-oil; the presence of the first is detected by Pontet’s reagent (made by dissolving 6 parts Hg in 7.5 parts of N03H of 36° in the cold), which converts pure olive-oil into a solid mass, while an oil adulterated with a drying oil remains semi-solid. A contamination with oil of sesame is indicated by the production of a green color, with a mixture of N03H and S04H.,. Peanut-oil, an exceedingly common adulterant in this country, is recognized by the following method: ten grams of the oil are saponified ; the soap is decomposed with HC1; the NEUTRAL OILS AND FATS. 205 liberated fatty acids dissolved in 50 c.c. of strong alcohol ; the solution precipitated with lead acetate ; the precipitate washed with ether ; the residue decomposed with hot dilute HC1 ; the oily layer separated and ex- tracted with strong alcohol ; the alcoholic fluid, on evaporation, yields crystals of arachaic acid, if the oil contains peanut-oil. Cocoa-butter—Oleum theobromce (U. S., Br.)—is, at ordinary tempera- tures, a whitish or yellowish solid of the consistency of tallow, and having an odor of chocolate and a pleasant taste ; it does not easily become ran- cid. The most reliable test of its purity is its fusing-point, which should not be much below 33J (91°.4 F.). Linseed oil—Flaxseed oil—Oleum lini ( U S., Br.)—is a dark, yellowish- brown oil of disagreeable odor and taste. In it oleic acid is, at least par- tially, replaced by linoleic acid, whose presence causes the oil, on exposure to air, to absorb oxygen and become thick and finally solid. This drying power is increased by boiling the oil with litharge (boiled oil). Castor-oil—Oleum ricini (U S., Br.)—is usually obtained by expression of the seeds, although in some countries it is prepared by decoction or by extraction with alcohol. It is a thick, viscid, yellowish oil, has a faint odor and a nauseous taste. It is more soluble in alcohol than any other fixed vegetable oil, and is also very soluble in ether. It saponifies very readily. Ammonia separates from it a crystalline solid, fusible at 66° (158°.8 F.) ricinolamide. Hot N03H attacks it energetically, and finally converts it into suberic acid. Whale-oil—Train-oil—obtained by trying out the fat or blubber of the “rightwhale” and of other species of balcence. It is of sp. gr. 0.924 at 15° (59 J F.) ; brownish in color ; becomes solid at about 0° ; has a very nause- ous taste and odor. It is colored yellow by SO ,H2; and is blackened by Cl. Neat’s-foot oil—is obtained by the action of boiling H20 upon the feet of neat cattle, horses, and sheep, deprived of the flesh and hoofs. It is straw-yellow or reddish-yellow, odorless, not disagreeable in taste, not prone to rancidity, does not solidify at quite low temperatures; sp. gr. at 153 (59° F.) = 0.916. It is bleached, not colored, by chlorine. Lard-oil—Oleum adipis (U. S.)—obtained in large quantities in the United States as a by-product in the manufacture of candles, etc., from pig’s fat. A light yellow oil, used principally as a lubricant; is not colored by SOtH2, but is colored brown by a mixture of SO,H„ and N03H. Tallow-oil—obtained by expression with a gentle heat from the fat of the ox and sheep. Sp. gr. 0.9003 ; light yellow in color. Colored brown by S04H,. Formerly this oil, under the trade-name of “ oleic acid,” was simply a by-product in the manufacture of stearin candles; of late years, however, it is specially prepared for the manufacture of oleo-margarine. Cod-liver oil—Oleum morrhuce (U. S., Br.)—is obtained from the livers of cod-fish, either by extraction with water heated to about 80° (176° F.), or by hanging the livers in the sun and collecting the oil which drips from them. There are three commercial varieties of this oil: a. Brown.—Dark brown, with greenish reflections; has a disagreeable, irritating taste ; faintly acid; does not solidify at —13° (8°.6 F.). b. Pale brown.—Of the color of Malaga wine ; has a peculiar odor and a fishy, irritating taste ; strongly acid. c. Pale.—Golden yellow ; deposits a white fat at —13° (8°.6 F.); has a fresh odor, slightly fishy, and a not unpleasant taste, without after-taste. Pure cod-liver oil, with a drop of S04H„, gives a bluish-violet aureole, which gradually changes to crimson, and later to brown. A drop of fum- ing NOsH dropped into the oil is surrounded by a pink aureole if the oil 206 MANUAL OF CHEMISTRY. be pure ; if largely adulterated with other fish-oils, the pink color is not observed and the oil becomes slightly cloudy. Fresh cod-liver oil is not colored by rosaniline. If a third of the oil be distilled, the distillate be- comes solid ; while if it be contaminated with vegetable oils, the distillate becomes liquid. Cod liver oil contains, besides the glycerides of oleic, palmitic and stearic acids, those of butyric and acetic acids ; certain biliary principles (to whose presence the sulphuric acid reaction given above is probably due), a phosphorized fat of undetermined composition ; small quantities of bro- mine and iodine, probably in the form of organic compounds ; a peculiar fatty acid called gadinic acid, which solidities at 60° (140° F.); and a brown substance called gaduin or gadinine. To which, if to any, of these substances cod-liver oil owes its value as a therapeutic agent is still unknown, although many theories have been advanced. Certain it is, however, that one of the chief values of this oil is as a food in a readily assimilable form. Solid Animal Fats.—The glycerides of stearic, palmitic, and oleic acids exist, in health, in nearly all parts of the body ; in the fluids in solu- tion or in suspension, in the form of minute oil-globules ; incorporated in the solid or semi-solid tissues, or deposited in collections in certain loca- tions, as under the skin, enclosed in cells of connective tissue, in which the mixture of the three glycerides is in such proportion that the contents of the cells are fluid at the temperature of the body. The total amount of fat in the body of a healthy adult is from 2.5 to 5 per cent, of the body-weight, although it may vary considerably from that proportion in conditions not, strictly speaking, pathological. The approximate quantities of fat in 100 parts of the various tissues and fluids, in health, are the following : Urine ? Perspiration 0.001 Vitreous humor .... 0.002 Saliva 0.02 Lymph 0.05 Synovial fluid 0.06 Amniotic fluid 0.2 Chyle 0.3 Mucus 0.4 Blood 0.4 Cartilage 1.3 Bone 1.4 Bile 1.4 Crystalline lens 2.0 Liver 2.4 Muscle 3.3 Hair 4.2 Milk 4.3 Cortex of brain 5.5 Brain 8.0 Hen’s egg 11.6 White matter of brain. 20.0 Nerve-tissue 22.1 SSpinal cord 23.6 Fat-tissue 82.7 Marrow 96.0 The amount of fat, under normal conditions, is usually greater in women and children than in men ; generally greater in middle than in old age, although in some individuals the reverse is the case ; greater in the inhab- itants of cold climates than in those of hot countries. In wasting from disease and from starvation the fats are rapidly ab- sorbed, and are again as rapidly deposited when the normal condition of affairs is restored. Besides, as a result of the tendency to corpulence, which in some indi- viduals amounts to a pathological condition, fats may accumulate in cer- tain tissues as a result of morbid changes. This accumulation may be due either to degeneration or to infiltration. In the former case, as when mus- cular tissue degenerates in consequence of long disuse, the natural tissue disappears and is replaced by fat; in the latter case, as in fatty infiltration of the heart, oil-globules are deposited between the natural morphological elements, whose change, however, may subsequently take place by true fatty degeneration, due to pressure. Fatty degeneration of the liver and of other organs occurs also in phthisis, chronic heart, and lung affections, NEUTRAL OILS AND FATS. 207 as a result of overfeeding, from the abuse of alcoholic stimulants, and from the action of certain poisons, especially of phosphorus. Tumors com- posed of adipose tissue occur and are known as “ lipomata.” The greater part of the fat of the body enters it as such with the food. Not unimportant quantities are, however, formed in the body, and that from the albuminoid as well as from the starchy and saccharine constitu- ents of the food. By what steps this transformation takes place is still uncertain, although there is abundant evidence that it does occur. Those fats taken in with the food are unaltered by the digestive fluids, except in that they are freed from their enclosing membranes in the stomach, until they reach the duodenum ; here, under the influence of the pancreatic juice, the major part is converted into a fine emulsion, in which form it is absorbed by the laeteals. A smaller portion is saponified, and the products of the saponification, free fatty acids, soaps, and glycerin, subsequently absorbed by laeteals and blood-vessels. The service of the fats in the economy is undoubtedly as a producer of heat and force by its oxidation ; and by its low power of conducting heat, and the position in which it is deposited under the skin, as a retainer of heat produced in the body. The fats are not discharged from the system in health, except the excess contained in the food over that which the absorbents are capable of taking up, which passes out with the feces; a small quantity distributed over the surface in the perspiration and seba- ceous secretion (which can hardly be said to be eliminated) ; and a mere trace in the urine. Butter.—The fat of milk, separated and made to agglomerate by agi- tation, and more or less salted to insure its keeping. It consists of the glycerides of stearic, palmitic, oleic, butyric, capric, caprylic, and caproic acids, with a small amount of coloring matter, more or less water and salt, and caseine. Good, natural butter contains 80-90 per cent, of fat, 6-10 per cent, of water, 2-5 per cent, of curd, and 2-5 per cent, of salt; fuses at from 32°.8 to 34°.9 (91°-94°.8 F.). Butter is adulterated with excess of water and salt, starch, animal fats other than those of butter, and artificial coloring matters. Excess of salt and water are usually worked in together, the former up to 14 per cent, and the latter to 15 per cent. To determine the pres- ence of an excess of water, about 4 grams (60 grains) of the butter, taken from the middle of the lump, are weighed in a porcelain capsule, in which it is heated over the water-bath, as long as it loses weight; it is then weighed again ; the loss of weight is that of the quantity of water in the original weight of butter, less that of the capsule. The proportion of salt is determined by incinerating a weighed quantity of butter and determining the chlorine in the ash by the nitrate of silver method (see Sodium chloride). Boughly, the weight of the ash may be taken as salt. Starch is detected by spreading out a thin layer of butter, adding solution of iodine, and examining under the microscope for purple spots. To determine the presence of foreign fats, the best method is that of Angell and Hehner. A pear-shaped bulb of thin glass is made of such size as to displace 1 c.c. water, is weighted with mercury until it weighs 3.4 grams (52.5 grains), and the pointed end closed by fusion. The but- ter to be tested is fused in a beaker over the water-bath and when quite fluid is poured out into a test-tube, about f inch diameter and 6 inches long, which is kept moderately warm and upright until the fat has separated in a clear layer above the water; and then immersed in water at 15° (59°. F.) until the fat has solidified. The test-tube is then ar- 208 MANTJAL OF CHEMISTRY. ranged as shown m Fig. 38, the bulb being laid upon the surface of the fat. The water in the beaker is now heated until the globular part of the bulb has just sunk below the surface of the fat, at which time the height of the thermometer is noted ; this is the “ sinking-point.” The sinking-point of pure butter is 34°.3 to 36°.3 (93°.7-97°.3 F.), that of oleo-margarine is lower, that of butter adulter- ated with other fats is higher. Soaps—are the metallic salts of stearic, palmitic and oleic acids; those of K, Na and NH4 are soluble, those of the other metals insoluble. Those of Na are hard, those of K soft. Soap is made from almost any oil or fat, the best from olive-oil, or peanut- or palm-oil, and lard. The first step in the process of manufacture is the saponifi- cation of the fat, which consists in the decomposition of the glyceric ethers into glycerin and the fatty acids, and the combination of the latter with an alkaline metal. It is usually effected by gradually adding the fluid fat to a weak boiling solution of caustic soda or potassa to saturation. From this weak solution the soap is separated by “ salting,” which consists in add- ing, during constant agitation, a solution of caustic alkali, heavily charged with common salt, until the soap separates in grumous masses, which float upon the surface and are separated. Finally the soap is pressed to separate adhering water, fused, and cast into moulds. White castile soap—Sapo (U. S.)—Sapo durus (Br.)—is a Na soap made from olive-oil; strongly alkaline, hard, not greasy, very soluble ; contains 21 per cent. H20. Sapo mollis (Br.) is a K soap made from olive-oil, and contains an excess of alkali and glycerin. Yellow soap is made from tallow or other animal fat, and contains about \ its weight of rosin. Emplastrum plumbi (V. S. ; Br.) is a lead soap, prepared by saponifying olive-oil with litharge. The soaps are decomposed by weak acids, with liberation of the fatty acid ; by compounds of the alkaline earths, with formation of an insolu- ble soap ; and in the same way by most of the metallic salts. Phosphorized fats—Lecithins—are highly complex substances ob- tained from brain-tissue, the yolks of hen’s eggs and fish roes. They are yellowish-white, waxy, hygroscopic solids ; imperfectly crys- talline ; soluble in alcohol and ether; insoluble in water, in which they swell like starch. They form compounds with certain salts and with acids. They are very prone to decomposition ; and may be made to yield neurine (q. v.) ; stearic, palmitic or oleic acid and a peculiar acid, glycerophosphoric acid. Their constitution is indicated in the following formula?, by which it will be seen that they are glycerophosphoric acid in which the remain- ing H atoms of the glycerin have been replaced by radicals of the fatty acids, and the remaining oxhydryls of the phosphoric acid by neurine: fig. 38. CH-OH I CH-OH L-0P0/g! CH-O (C18H360)" CH-0 (C18H350)' I CH -0P0/°HN Glyccrophosphoric acid. Stearine lecithin. THIRD SERIES OF HYDROCARBONS. 209 THIRD SERIES OF HYDROCARBONS. •Sebies C„H2„.2. The terms of this series at present known are Acetylene C2H2 Allylene C3H4 Crotonylene C4H6 Valerylene C6H8 Rutylene Ci0Hi8 Benylene Cj 5H2 8 Acetylene—Ethene—C2H2—26—exists in coal gas and is formed in the decomposition, by heat or otherwise, of many organic substances. It is best prepared by passing a slow current of coal gas through a narrow tube, traversed by induction sparks; directing the gas through a solution of cuprous chloride ; and collecting and decomposing the precipitate by HC1. It may be obtained by direct synthesis from H and C, by producing the electric arc between carbon points in a glass globe filled with hydrogen. It is a colorless gas, rather soluble in H20 ; has a peculiar, disagree- able odor; such as is observed when a Bunsen burner burns within the tube. It forms explosive mixtures with O. It unites with N, under the influence of the electric discharge, to form hydrocyanic acid. Mixed with Cl, it detonates violently in diffuse daylight, without the aid of heat. It may be made to unite with itself to form its polymeres benzene, C6H6, styrolene, C8H8 and naphthydrene, C10H10. Its presence may be detected by the formation in an ammoniacal solu- tion of cuprous chloride of a blood red precipitate, which is explosive when dry. It is probable that explosions which sometimes occur in brass or copper pipes, through which illuminating gas is conducted, are due to the formation of this compound. Illuminating gas—is now manufactured by a variety of processes, almost every company using some modification of the method, or of the nature and proportion of the materials ; thus we have gas made from wood, from coal, from fats, from petroleum, and by the decomposition of H,0 and subsequent charging of the gas with the vapor of naphtha. The typical process is that in which the gas is produced by heating bituminous coal to bright redness in retorts. As it issues from the re- torts the gas is charged with substances volatile only at high tures; these are deposited in the condensers or coolers, and form coal- or gas-tar. From the condensers the gas passes through what are known as “ scrubbers” and “ lime-purifiers,” in which it is deprived of ammoni- cal compounds and other impurities. As it comes from the condensers, coal-gas contains: * Acetylene. * Ethylene. * Marsh-gas. * Butylene. * Propylene. * Benzene. * Styrolene. * Naphthalene. * Acenaphthalene. * Fluorene. * Propyl hydride. * Butyl hydride. Hydrogen. • • Carbon monoxide. • ■ Carbon dioxide. •• Ammonia. ■ Cyanogen. •• Sulphocyanogen. f Hydrogen sulphide, f Carbon disulphide, f Sulphuretted hy- drocarbons, f Nitrogen, f Aqueous vapor. Iii passing through the purifiers the gas is freed of the impurities to a greater or less extent, and, as usually delivered to consumers, contains : * Marsh-gas. * Acetylene. * Ethylene. X Hydrogen. f Nitrogen, f Aqueous vapor. f Carbon monoxide, f Carbon dioxide. * Vapors of Hydrocarbons. * Illuminating constituents. f Impurities. X Diluent. 210 MANUAL OF CHEMISTRY. TETRATOMIC ALCOHOLS. Series C„H2„ + 204. Very few of these compounds have yet been obtained. They may be regarded as the hydrates of the hydrocarbons CnH2n_a ; as the glycols are the hydrates of the ethylene series. ch2oh I CHOH Erythrite—Phycite— | =C4H6(OH)4—122—is a product of de- CHOH I ch2oh composition of erythrine, C20H22O1#, which exists in the lichens of the genus rocella. It crystallizes in large, brilliant prisms ; very soluble in H20 and in hot alcohol, almost insoluble in ether ; sweetish in taste ; its solutions neither affect polarized light, nor reduce Fehling’s solution, nor are capable of fermentation. Its watery solution, like that of sugar, is capable of dis- solving a considerable quantity of lime, and from this solution alcohol precipitates a definite compound of erythrite and calcium. By oxida- tion with platinum black it yields erythroglueic acid, C4H806. With fuming NOaH it forms a tetranitro compound, which explodes under the hammer. ACIDS DERIVABLE FROM ERYTHRITE. Theoretically erythrite should, by simple oxidation, yield two acids; one of the series C„H2nO., and another of the series CnH2„_206. Although both of these acids are known, only the first, erythroglueic acid, has been obtained by oxidation of erythrite : CH2OH CHOH I CHOH I ch2oh COOH I CHOH I CHOH I CH2OH COOH I CHOH I CHOH I COOH Erythrite. Erythroglucic acid. Tartaric acid. Tartaric acids—Acidurn tartaricum (U. S., Br.)—C4HfO(—150.— There exist four acids having the composition C4HB06, which differ from each other only in their physical properties, and are very readily converted into one another ; they are designated as : 1st, Right ; 2d, Left ; 3d, Inac- tive tartaric acid; 4th, Racemic acid. Right or Dextrotartaric acid crystal- lizes in large, oblique, rhombic prisms, having hemihedral facettes. Solu- tions of the acid and its salts are dextrogyrous. Lcevotartaric acid crystallizes in the same form as dextrotartaric acid, only the hemihedral facettes are on the opposite sides, so that crystals of ACIDS DERIVABLE FROM ERYTIIRITE. 211 the two acids, wdien held facing each other, appear like the reflections one of the other. Its solution and those of its salts are laevogyrous to the same degree that corresponding solutions of dextrotartaric acid are dex- trogyrous. Racemic add is a compound of the two preceding ; it forms crystals having no hemihedral facettes, and its solutions are without action on polarized light. It is readily separated into its components. Inactive tartaric acid, although resembling racemic acid in its crystalline form and inactivity with respect to polarized light, differs essentially from that acid in that it cannot be decomposed into right and left acids, and in the method of its production. The tartaric acid which exists in nature is the dextrotartaric ; it occurs, both free and in combination, in the sap of the vine and in many other vegetable juices and fruits. Although this is probably the only tar- taric acid existing in natui’e, all four varieties may and do occur in the commercial acid, being formed during the process of manufacture. Tartaric acid is obtained in the arts from hydropotassic tartrate, or cream of tartar (q. v.). This salt is dissolved in H„0 and the solution boiled with chalk until its reaction is neutral ; calcic and potassic tartrates are formed. The insoluble calcic salt is separated and the potassic salt decomposed by treating the solution with calcic chloride. The united de- posits of calcium-tartrate are suspended in H O, decomposed with the pro- per quantity of SOH, the solution separated from the deposit of calcium sulphate, and evaporated to crystallization. The ordinary tartaric acid crystallizes in large prisms ; very soluble in H.,0 and alcohol; acid in taste and reaction. It fuses at 170° (338° F.) ; at 180° (SSG0 F.) it loses H20, and is gradually converted into an anhy- dride ; at 200°-210° (392°-410° F.) it is decomposed with formation of pyruvic acid, C3H4Os, and pyrotartaric acid, CrH804; at higher tempera- tures COn, CO, H.,0, hydrocarbons and charcoal are produced. If kept in fusion some time, two molecules unite, with loss of H20, to form tartralic or ditartaric acid, CfH10On. Tartaric acid is attacked by oxidizing agents with formation of CO„, H20, and, in some instances, formic and oxalic acids. Certain reducing agents convert it into malic and succinic acids. With fuming N03H it forms a dinitro-compound, which is very unstable, and which, when decomposed below 36° (968 F.), yields tartaric acid. It forms a precipitate with lime-water, soluble in an excess of H,,0 ; in not too dilute solution it forms a precipitate with potassium sulphate solution; it does not precip- itate with the salts of Ca. When heated with a solution of auric chloride it precipitates the gold in the metallic form. As its formula indicates (see above), tartaric acid is tetratomic and dibasic. It has a great ten- dency to the formation of double salts, such as tartar emetic (q. v.). When taken into the economy, as it constantly is in the form of tar- trates, the greater part is oxidized to carbonic acid (carbonates) ; but, if taken in sufficient quantity, a portion is excreted unchanged in the urine and perspiration. The free acid is poisonous in large doses. Citric acid—Acidum citricum (U. S., Br.).—0fHHO7 + Aq—192 4- 18—is best considered in this place, although its constitution is different from that of tartaric acid. It exists in the juices of many fruits—lemon, strawberry, etc. It is obtained from lemon-juice, which is filtered, boiled, and saturated with chalk. The insoluble calcium citrate is separated and decomposed with SO H , the solution filtered, and evaporated to crystallization. It crystallizes in large, right rhombic prisms, which lose their aq. at 212 MANUAL OF CHEMISTRY. 100° (212° F.); very soluble in water, less soluble in alcohol, sparingly soluble in ether ; heated to 100° (212° F.) it fuses ; at 175° (347° F.) it is decomposed, with loss of H20 and formation of aconitic acid, CfHfO0; at a higher temperature C02 is given off, and itaconic acid, C.H 04, and citraconic acid, C5Hf04, are formed. Concentrated S04H2 decomposes it with evolution of CO ; oxidizing agents convert it injto formic acid and C02, or into acetone and CO„, or into oxalic and acetic acids and C02. It is tetratomic and tribasic. In the body its salts are oxidized to carbonates. FOURTH SERIES OF HYDROCARBONS Series C„H2?l_4. But one of the lower terms of this series is known ; this is valylene, C.H6, obtained by the action of an alcoholic solution of potash on valery- lene dibromide. It is a liquid, boiling at 45° (113° F.). Among the higher terms of the series are many substances of industrial and medical importance. Terebenthene—C10H16—136—is the type of a great number of iso- meric substances existing in the volatile oils or essences. It is the chief con- stituent of oil of turpentine. To obtain it in a state of purity, oil of turpentine is mixed with an alkaline carbonate, and distilled in vacuo over a water-bath, or by frac- tional distillation of the crude oil, those portions being collected which pass over at about 156° (312°.8 F.). Pure terebenthene is a colorless, mobile liquid ; has the peculiar odor of turpentine; boils at about 156° (312°.8F.); burns with a smoky, luminous flame. Obtained from the turpentine of pinus maritima, it is laevogyrous, purified by distillation in vacuo, [a]D = —42°.36, by frac- tional distillation, [a]D = — 40°.32 ; that obtained from pinus australis is dextrogyrous, [ojD = + 18°.9 ; specific gravity at 0° (32° F.) = 0.8767. It absorbs oxygen rapidly from the air, whether pure or in the com- mercial essence, becoming thick and finally gummy. Oxidizing agents, such as N03H, attack it energetically, causing it to ignite and burn sud- denly, with separation of a large volume of carbon. HC1 unites with it to form a number of compounds, as do also HI and HBr—all the compounds having the odor of camphor. When mixed with N03H, diluted with alco- hol, and exposed to the air, it forms a crystalline pseudo-glycol, terpine. Cl, Br and I form compounds of substitution or of addition. Turpentine—Terebenlhina (U. S.)—is the name given to the concrete juice of various species of trees of the genera Pinus, Abies, and Larix, which consist of terebenthene, its isomeres, and resinous and other sub- stances. The product differs in composition and properties according to the kind of tree from which it is produced. White turpentine—Common American turpentine—obtained from Pinus palustris and P. tceda; is yellowish-white, semi-fluid at summer tempera- ture, hard and solid when cooled ; on exposure to air it becomes dry, hard, and brittle. It is usually subjected to distillation near the place of its col- lection, by which process it is separated into the volatile oil, or essence of turpentine (q. v.), and rosin, or colophony (q. v.). European turpentine— Bordeaux turpentine—obtained from P. sylvestris and P. maritima. Canada turpentine—Canada balsam—Balsam of fir—Terebenthina canadensis (U. S.) FOURTH SERIES OF HYDROCARBONS. 213 —is from abies balsamea. It is a tenacious semi-solid, of the consistency of honey when fresh, colorless or yellowish, sticky, bitter in taste, and having a balsamic odor; when long exposed to the air, or when heated over the water-bath, its volatile constituents are lost, and it is converted into a hard brittle mass. Venice turpentine—produced from larix Europcea— is a thick, viscid liquid, yellowish or greenish in color ; soluble in alcohol; does not concrete as readily as other turpentines. Chian turpentine, the product of pistachia terebinthus, is a thick, greenish-yellow liquid. Essence or Turpentine—Oil of turpentine—Spirits of turpentine—Oleum terebinthince (U. S., Br.)—is the volatile product of the distillation of tur- pentine. It is not identical with terebenthene, although that substance is its main constituent; it contains also hydrocarbons isomeric with turpen- tine and substances containing oxygen, which either pre-exist in the turpen- tine, or, more usually, result from the method of preparing the oil. When recently distilled, it is a colorless, limpid, neutral liquid ; sp. gr. 0.86 ; usually hevogyrous, sometimes dextrogyrous. When exposed to the air it rapidly becomes yellow and viscid. The action of reagents upon it is practically the same as upon terebenthene. The number of isomerides existing in oil of turpentine is very great; some are optically active, others inactive ; they also vary in their sp. gr., fusing- or boiling-points, and capacity for absorbing oxygen. Isomeres of Terebenthene.—There exist a great number of bodies, the products of distillation of vegetable substances, which are known as essences, essential oils, volatile oils or distilled oils. They resemble each other in being odorous, oily, sparingly soluble in water, more or less soluble in alcohol and ether ; colorless or yellowish, inflammable, and prone to be- come resinous on exposure to air. They are not simple chemical com- pounds, but mixtures, and in many of them the principal ingredient is a hydrocarbon, isomeric with terebenthene, and consequently having the composition Some contain hydrocarbons, others aldehydes, acet- ones, phenols, and ethers. Of the numerous other hydrocarbons closely related to terebenthene, but two require further consideration as being the principal constituents of caoutchouc and gutta-percha. Caoutchouc—India-rubber—is a peculiar substance existing in sus- pension in the milky juice of quite a number of trees growing in warm climates. It is, when pure, a mixture of two hydrocarbons—caoutchene, C10H16, and isoprene, CfH_. The commercial article is yellowish-brown; sp. gr. 0.919 to 0.942 ; soft, flexible ; almost impermeable, but still capable of acting as a dialyzing membrane when used in sufficiently thin layers. It is insoluble in HO and alcohol, both of which, however, it absorbs by long immersion, the former to the -extent of 25 per cent., and the latter of 20 per cent., of its own weight; it is soluble in ether, petroleum, fatty and essential oils ; its best solvent is carbon disulphide, either alone, or, better, mixed with 5 parts of absolute alcohol. It is not acted upon by dilute mineral acids, but is attacked by concen- trated N03H and 80,14,,, and especially by a mixture of the two. Alkalies tend to render it tougher, although a solution of soda of 40° B. renders it soft after an immersion of a few hours. Cl attacks it after a time, de- priving it of its elasticity, and rendering it hard and brittle. When heated it becomes viscous at 145° (293° F.), and fuses at 170°-180° (347°-356 3 F.) to a thick liquid, which, on cooling, remains sticky and only regains its primitive character after a long time. On contact with flame it ignites, 214 MANUAL OF CHEMISTRY. burning with a reddish, smoky flame, which is extinguished with dif- ficulty. The most valuable property of india-rubber, apart from its elasticity, is that which it possesses of entering into combination with S to form what is known as vulcanized rubber, which is produced by heating together the normal caoutchouc and S to 130°-150° (266°-302° F. j. Ordinary vulcanized rubber differs materially from the natural gum in its properties ; its elas- ticity and flexibility are much increased; it does not harden when ex- posed to cold ; it only fuses at 200° (392° F.) ; finally, it resists the action of reagents, of solvents, and of the atmosphere much better than does the natural gum. Frequently rubber tubing is too heavily charged with sulphur for cer- tain chemical uses, in which case it may be desulphurized by boiling with dilute caustic soda solution. Hard rubber, vulcanite, or ebonite, is a hard, tough variety of vulcanized rubber, susceptible of a good polish, and a non-conductor of electricity. It contains 20 to 35 per cent, of S (the ordinary vulcanized rubber contains 7 to 10 per cent.). Gutta-percha—is the concrete juice of isonandra gutta. It is a tough, inelastic, brownish substance, having an odor similar to that of caout- chouc ; at ordinary temperatures it is rather hard, but when warmed it becomes soft and may be moulded, or even cast, so as to assume any form, which it retains on cooling ; it may be welded at slightly elevated temper- atures, is a good insulating and waterproofing material, and is tough and pliable. It is insoluble in water, alkaline solutions, dilute acids, includ- ing hydrofluoric, and in fatty oils; it is soluble in benzene, oil of turpentine, essential oils, chloroform, and especially in carbon disulphide. A solution in chloroform is known as traumaticine or Liq. gutta perchce (U. 8.), and is used to obtain, by its evaporation, a thin film of gutta-percha over parts which it is desired to protect from the air. It is attacked by NOsH and SO.H,,. When exposed to air and light, it is gradually changed from the sur- face inward, assuming a sharp, acid odor, becoming hard and cracked, and even a conductor of electricity. Gutta-percha is a more complex substance than caoutchouc, and seems to be made up of three substances : Gutta, C,nHp4, 75-82 per cent., a white, tough substance, fusing at 150° (302° F.), soluble in the ordinary solvents of gutta-percha, but insoluble in alcohol and ether. Albane, C„nH3202, 14- 19 per cent., a white, crystalline resin, heavier than water, fusible at 160° (320° F.) ; soluble in benzene, essence of turpentine, carbon disulphide, ether, chloroform, and hot absolute alcohol; not attacked by HC1. Flu- viale, 4-6 per cent., C„0H,2O, a yellowish resin, slightly heavier than water, hard and brittle at 0° (32° F.), soft at 50° (122° F.), liquid at 100° (212° F.); soluble in the solvents of gutta-percha. Camphors and Resins.—Most of the essential oils yield on distilla- tion two products of different boiling-points; one of these is a hydrocarbon, in most instances of the terebenthene series, liquid at ordinary tempera- tures, and sometimes known as an eleoptene. The other, of higher boiling- point, and solid at ordinary temperatures, designated a stearoptene, is an oxidized product, and either exists as such in the vegetable exudation, or is produced under subsequent treatment. The camphors are probably aldehydes or alcohols corresponding to hydrocarbons related to tereben- thene, although their constitution is still uncertain. Common camphor—Japan camphor—Laurel camphor—Gampholic aldehyde—Camphora (U. 8., Br.)—Ci0HlcO—152.—Three modifications are FOURTH SERIES OF HYDROCARBONS. 215 known, which seem to differ from each other only in their action upon polarized light: (1.) Dextro camphor — camphore officinarum; obtained from laurus camphora—[a] D = -f 47°.4. (2.) Laevo camphor ; obtained from matricaria postlanium—[a]D = —47°.4. (3.) Inactive camphor, obtained from the essential oils of rosemary, sage, lavender, and origanum. The first is the ordinary camphor of the shops. It is a white, translu- cent, crystalline solid ; sp. gr. 0.986-0.996, hot and bitter in taste ; aro- matic ; sparingly soluble in H20 ; quite soluble iu ether, acetic acid, methylic and ethylic alcohols and the oils; fuses at 175° (347° F.); boils at 204° (399°. 2 F.); sublimes at all temperatures. It ignites readily and burns with a luminous flame. Cold NOH dis- solves it, and from the solution H,0 precipitates it unchanged. Boiling NO,H, or potassium permanganate, oxidizes it to dextro camphoric acid, Cl0H16O4. Concentrated SO,11., forms with it a black solution, from which H,0 precipitates an oily material called camphene. Distilled with P2Or, it yields cymene, Cl0H,4. Alkaline solutions, by long heating under pressure, convert it into camphic acid, C10H16O2, and borneol. Cl attacks it with difficulty. Br unites with it to form an unstable compound, which forms ruby-red crystals having the composition C10H]4OBr2. These crystals, when heated to 80°-90° (176°-194° F.), fuse and give off HBr, there re- maining an amber-colored liquid, which solidifies on cooling and yields, by recrystallization from boiling alcohol, long, hard, rectangular crystals of monobromo camphor—camphora monobromata (U. S.)—C10H]5OBr. When vapor of camphor is passed over a mixture of fused potash and lime, heated to 300°-400° (572°-752° F.), it unites directly with the potash to form the K salt of campholic acid, C]0H18O2. Borneol—Borneo camphor—Camphol—Gamphyl alcohol—C10H18O— 154—is usually obtained from dryobalanops camphora, although it may be obtained from other plants, and even artificially by the hydrogenation of laurel camphor. The product from these different sources is the same chemically, so far as we can determine, but varies, like the modifications of camphor, in its action on polarized light. It forms small, white, transparent, friable crystals ; has an odor which recalls at the same time those of laurel camphor and of pepper ; has a hot taste ; is insoluble in water, readily soluble in alcohol, ether, and acetic acid ; fuses at 198° (388°.4 F.), boils at 212° (413°.6 F.). It is a true alcohol, and enters into double decomposition with acids to form ethers. When heated with P206, it yields a hydrocarbon, borneene, C10H16. Oxidized by N03H, it is converted into laurel camphor. Menthol—Menthyl alcohol—C]0H20O—156—exists in essential oil of peppermint. It crystallizes in colorless prisms ; fusible at 36° (96°.8 F.); sparingly soluble in water ; readily soluble in alcohol, ether, carbon disul- phide, and in acids. Corresponding to it are a series of menthyl ethers. Euealyptol—C]2H„oO —180—is contained in the leaves of eucalyptus globulus ; it is liquid at ordinary temperatures, and boils at 175° (347° F.) ; by distillation with phosphoric anhydride it yields eucalyptene, C12H18. Terpine— Terebenthene bihydrate—C10H1(,,2H.,O + Aq—172 + 18—is sometimes spontaneously deposited from oil of turpentine containing water ; it may be obtained by frequently agitating for a month or more a mixture of oil of turpentine, alcohol, and ordinary nitric acid. It forms fine, large, rhombic prisms ; sp. gr. 1.0994 ; sparingly soluble in cold water; soluble in hot water, alcohol, and ether; fusible at 103° (217°.4 F.). Terpinol—(C10H]6)2H„O —290—is formed when terpine in solution in warm water is treated with a very small quantity of S04H2 or HC1, and 216 MANUAL OF CHEMISTRY. distilled. It is a colorless liquid ; lias an odor of hyacinth ; sp. gr. 0.852 ; boils at 168° (334°.4 F.), at which temperature it suffers partial decompo- sition. It appears to possess the function of an ether. Resins—are generally the products of oxidation of the hydrocarbons allied to terebenthene ; are amorphous (rarely crystalline) ; insoluble in water ; soluble in alcohol, ether, and essences. Many of them contain acids. They may be divided into several groups, according to the nature of their constituents: (1.) Balsams; which are usually soft or liquid, and are distinguished by containing free cinnamic or benzoic acid (q. v.). The principal members of this group are benzoin, liquidambar, Peru balsam, styrax, and balsam tolu. (2.) Oleo-resins consist of a true resin mixed with an oil, and usually with an oxidized product other than cinnamic or benzoic acid. The principal members of this group are Burgundy and Canada pitch, Mecca balsam, and the resins of capsicum, copaiva, cubebs, elemi, labdanum, and lapulin. (3.) Gum-resins are mixtures of true resins and gums. Many of them are possessed of medicinal qualities ; aloes, ammoniac, asafcetida, bdellium, euphorbium, galbanum, gamboge, guaiac, myrrh, olibanum, opoponax, and scammony. (4.) True resins are hard sub- stances obtainable from the members of the three previous classes, and containing neither essences, gums, nor aromatic acids. Such are colophony or rosin, copal, dammar, dragon's blood, jalap, lac, mastic, and sandarac. (5.) Fossil resins, such as amber, asphalt, and ozocerite. CARBOHYDRATES. These substances are composed of C, H and O ; they all contain C6, or some multiple thereof; and the H and O which they contain is always in the proportion of Ha to O. Their constitution is still unknown ; prob- ably some are aldehydes, others alcohols and others ethers. Most of them are constituents of animal or vegetable organisms, and have not been obtained by complete synthesis. They are divisible into three groups, the members of each of which are isomeric with each other : I. Glucoses. «(C6H1206.) +Glucose. (Dextrose.) — Laevulose. Mannitose. 4-Galactose. Inosite. — Sorbin. —Eucalin. II. Saccharoses. "(CjsHjjOj,.) 4-Saccharose. 4-Lactose. 4-Maltose. 4-Melitose. 4-Melezitose. 4-Trehalose. 4-Mycose. Synanthrose. 4-Parasaccharose. III. Amyloses. »(c6h10o5.) 4- Starch. 4-Glycogen. + Dextrin. — Inulin. Tunicin. Cellulose. Gums. Glucoses, C6Hr,06—180 Glucose—Grape-sugar—Dextrose—Liver-sugar—Diabetic sugar.—The substance from which this group takes its name exists in all sweet and acidulous fruits ; in many vegetable juices ; in honey; in the animal economy in the contents of the intestines, in the liver, bile, thymus, heart, lungs, GLUCOSES. 217 blood, and in small quantity in the urine. Pathologically it is found in the saliva, perspiration, faeces, and largely increased in the blood and urine in diabetes mellitus (see below). It may also be obtained by decomposi- tion of certain vegetable substances called glucosides (q. v.). It is prepared artificially by heating starch or cellulose for 24 to 36 hours with a dilute mineral acid (S04HJ. Glucose obtained by this method is liable to contamination with traces of arsenic, which it receives from the S04H,. Starch is also converted into glucose by the influence of diastase, formed during the germination of grain. Glucose crystallizes with difficulty from its aqueous solution, in white, opaque, spheroidal masses containing 1 aq.; from alcohol in fine, trans- parent, anhydrous prisms; at about 60° (140° F.) in dry air the hydrated variety loses H ,0. It is soluble in all proportions in hot H20 ; very solu- ble in cold H,0 ; soluble in alcohol. It is less sweet and less soluble than cane sugar. Its solutions are dextrogyrous : [a] D = + 52°.85. At 170° (338° F.) it loses H20 and is converted into glucosan, C!;H10O.. Hot dilute mineral acids convert it into a brown substance, ulmic acid, and, in the presence of air, formic acid. It dissolves in concentrated S04H„ without coloration, forming sidphoglucic acid. Cold concentrated N03H converts it into nitro-glucose; hot dilute NO.(H oxidizes it to a mixture of oxalic and oxysaccharic acids. With organic acids it forms ethers. Its solutions dissolve potash, soda, lime, baryta, and the oxides of Pb and Cu, with which it forms compounds. When its solutions are heated with an alkali they assume a yellow or brown color, and give off a molasses-like odor, from the formation of glucic and melassic acids. Glu- cose in alkaline solution exerts a strong reducing action, which is favored by heat; Ag, Bi, and Hg are precipitated from their salts ; and cupric are reduced to cuprous compounds with separation of cuprous oxide. In the presence of yeast, at suitable temperatures, glucose undergoes alco- holic fermentation. Physiological.—The greater part of the glucose in the economy in health is introduced with the food, either in its own form or as other car- bohydrates, which by digestion are converted into glucose ; a certain quantity is also produced in the liver at the expense of glycogen, a for- mation which continues for some time after death. In some forms of diabetes the production of glucose in the liver is undoubtedly greatly increased. The quantity of sugar normally existing in the blood varies from 0.81 to 1.231 part per thousand ; in diabetes it rises as high as 5.8 parts per thousand. Under normal conditions, and with food not too rich in starch and saccharine materials, the quantity of sugar eliminated as such is exceed- ingly small—so small indeed that some observers have contested the fact of any being eliminated in health. It is oxidized in the body, and the ultimate products of such oxidation eliminated as CO,, and H .O. Whether or no intermediate products are formed, is still uncertain ; the probability, however, is that there are. The oxidation of sugar is impeded in diabetes. Where this oxidation, or any of its steps, occurs, is at present a matter of conjecture merely ; if, as is usually believed, glucose disappears to a marked extent in the passage of the blood through the lungs, the fact is a strong support of the view that its transformation into CO„ and H O does not occur as a simple oxidation, as the notion that sugar or any other sub- stance is “ burned ” in the lung, beyond the small amount required by the nutrition of the organ itself, is scarcely tenable at the present day. So long as the quantity of glucose in the blood remains at or below 218 MANUAL OF CHEMISTRY. the normal percentage, it is not eliminated in the urine in quantities appreciable by the tests usually employed ; when, however, the amount of glucose in the blood surpasses this limit from any cause, the urine becomes saccharine, and that to an extent proportional to the increase of glucose in the circulating fluids. The causes which may bring about such an increase are numerous and varied ; many of them are entirely consistent with health, and the mere presence of increased quantities of sugar in the urine is no proof, taken by itself, of the existence of diabetes. Sugar is detectable by the ordinary tests in the urine under the fol- lowing circumstances : Physiologically.—(1.) In the urine of pregnant women and during lac- tation. It appears in the latter stages of gestation and does not disappear entirely until the suppression of the lacteal secretion. (2.) In small quantities in sucking children from eight days to two and one half months. (3.) In the urine of old persons (seventy to eighty years). (4.) In those whose food contains a large amount of starchy or sac- charine material. To this cause is due the apparent prevalence of diabetes in certain localities, as in districts where the different varieties of sugar are produced. Pathologically.—(1.) In abnormally stout persons, especially in old per- sons and in women at the period of the menopause. The quantity does not exceed 8 to 12 grams per 1,000 c.c. (3.5-5.5 grains per ounce), and disappears when starchy and saccharine food is withheld. This form of glycosuria is liable to develop into true diabetes when it appears in young persons. (2.) In diseases attended with interference of the respiratory processes —lung diseases, etc. (3.) In diseases where there is interference with the hepatic circulation —hepatic congestion, compression of the portal vein by biliary calculi, cirrhosis, atrophy, fatty degeneration, etc. (4.) In many cerebral and cerebro-spinal disturbances—general paresis, dementia, epilepsy ; by puncture of the fourth ventricle. (5.) In intermittent and typhus fevers. (6.) By the action of many poisons—carbon monoxide, arsenic, chloro- form, curari; by injection into an artery of ether, ammonia, phosphoric acid, sodium chloride, amyl nitrite, glycogen. (7.) In true diabetes the elimination of sugar in the urine is constant, unless arrested by suitable regulation of diet, and not temporary, as in the conditions previously mentioned. The quantity of urine is increased, some- times enormously, and it is of high sp. gr. The elimination of urea is in- creased absolutely, although the quantity in 1,000 c.c. may be less than that normally existing in that bulk of urine. The quantity of sugar in diabetic urine is sometimes enormous ; an elimination of 200 grams (6.4 ounces) in twenty-four hours is by no means uncommon ; instances in which the amount has reached 400 to 600 grams (12.9-19.3 ounces) are recorded, and one case in which no less than 1,376 grams (45 ounces) were discharged in one day. The elimination is not the same at all hours of the day ; during the night less sugar is voided than during the day ; the hourly elimination increases after meals, reaching its maximum in 4 hours, after which it diminishes to reach the minimum in 6 to 7 hours, when it may disappear entirely ; this variation is more pronounced the more copious the meal. It is obvious from the above, that, in order that quantitative determinations of sugar in urine shall be of clinical value, it is necessary GLUCOSES. 219 that the determination be made in a sample taken from the mixed urine of twenty-four hours. The relation existing between the quantity of sugar in the blood and its elimination by the urine in diabetes is well shown by the following re- sults of Pavy, which also show the beneficial effects of restricting the diet: * Urine. Blood. Quantity in 24 hours. Specific gravity. Sugar excreted in 24 hours. Sugar in 1,000 parts. Sugar in 1,000 parts. Case I. Mixed diet Case II. Mixed diet Case II. Restricted diet Case III. Mixed diet Case III. Restricted diet Case IV. Partly restricted diet.. Case IV. Partly restricted diet, ) 3i months later.... j’ 6608 c.c. 6474 c.c. 3407 c.c. 5878 c.c. 3470 c.c. 1704 c.c 853 c.c 1040 1041 1031 1036 1033 1036 1034 751.6 grams. 633.0 grams. 245.2 grams. 567.7 grams. 115.8 grams. 21.81 grams. 14.40 grams. 109.91 94.08 61.34 93.39 45.49 48.11 31.76 5.763 5.545 2.625 4.970 2.789 1.848 1.543 Analytical Characters.—A saccharine urine is usually abundant in quantity, pale in color, of high sp. gi\, covered with a persistent froth on being shaken, and exhales a peculiar odor ; when evaporated it leaves a sticky residue. The presence of glucose in urine is indicated by the following tests: If the urine be albuminous, it is indispensable that the albumen be separated before any of the tests for sugar are applied ; this is done by adding one or two drops of acetic acid, or, if the urine be alkaline, just enough acetic acid to turn the reaction to acid, and no more, heating over the water-bath until the albumen has separated in flocks, and filtering. (1.) When examined by the polarimeter (see p. 38) it deviates the plane of polarization to the right. (2.) When mixed with an equal volume of liquor potassfe and heated, it turns yellow, and, if sugar be abundant, brown. A molasses-like odor is observable on adding N03H (Moore’s test). (3.) The urine, rendered faintly blue with indigo solution and faintly alkaline with sodium carbonate, and heated to boiling without agitation, turns violet and then yellow if sugar be present; on agitation the blue color is restored (Mulder-Neubauer test). (4.) About 1 c.c. of the urine, diluted with twice its bulk of water, is treated with two or three drops of cupric sulphate solution and about 1 c.c. of caustic potassa solution ; if sugar be present the bluish precipi- tate is dissolved on agitation, forming a blue solution ; the clear blue fluid, when heated to near boiling, deposits a yellow, orange, or red precipitate of cuprous oxide if sugar be present (Trommer’s test). In the applica- tion of this test an excess of cupric sulphate is to be avoided, lest the color be masked by the formation of the black cupric oxide. Sometimes no precipitate is formed, but the liquid changes in color from blue to yellow ; this occurs in the presence of small quantities of cupric salt and large quantities of sugar, the cuprous oxide being held in solution by the excess of glucose ; in this case the test is to be repeated, using a sample of urine more diluted with water. In some instances, also, the reaction is interfered with by excess of normal constituents of the urine, uric acid, creatinine, coloring matter, etc., and instead of a bright precipitate, a muddy deposit is formed ; when this occurs the urine is heated with ani- 220 MANUAL OF CHEMISTRY. mal charcoal and filtered ; the filtrate evaporated to dryness ; the residue extracted with alcohol; the alcoholic extract evaporated ; the residue re- dissolved in water, and tested as described above. (5.) Four or five c.c. of Fehling’s solution (see p. 221) are heated in a test-tube to boiling ; it should remain unaltered. The urine is then added guttatim ; if it contain sugar, the mixture turns green, and a yellow or red precipitate of cuprous oxide is formed, usually darker in color than that obtained by Trommer’s test. The absence of glucose is not to be in- ferred until a bulk of urine equal to that of the Fehling’s solution used has been added, and the mixture boiled from time to time without the formation of a precipitate. This test is the most convenient and the most reliable for clinical purposes. (6.) A few c.c. of the urine are mixed in a test-tube with an equal volume of solution of sodium carbonate (1 pt. crystal, carbonate and 3 pts. water), a few granules of bismuth subnitrate are added, and the mixture boiled for some time (until it begins to “bump,” if necessary). If sugar be present, the bismuth powder turns brown or black by reduction to elementary bismuth (Boettger’s test). No other normal constituent of the urine reacts with this test; a fallacy is, however, possible from the pres- ence of some compound, which, by giving up sulphur, may cause the formation of the black bismuth sulphide ; to guard against this, when an affirmative result has been obtained, another sample of urine is rendered alkaline and boiled with pulverized litharge; the powder should not turn black. (7.) A solution of sugar, mixed with good yeast and kept at 25° (77° F.) is decomposed into C02 and alcohol. To apply the fermentation-test to urine, take three test-tubes, A, B, and C, place in each some washed (or compressed) yeast, fill A completely with the urine to be tested, and place it in an inverted position, the mouth below the surface of some of the same urine in another vessel (the entrance of air being prevented, during the inversion, by closing the opening of the tube with the finger, or a cork on the end of a wire, until it has been brought below the surface of the urine). Fill B completely with some urine to which glucose has been added, and C with distilled water, and invert them in the same way as A ; B in saccharine urine, and C in distilled water. Leave all three tubes in a place where the temperature is about 25° (77° F.) for twelve hours, and then examine them. If gas have collected in B over the surface of the liquid, and none in A, the urine is free from sugar ; if gas have collected in both A and B, and not in C, the urine contains sugar ; if no gas have col- lected in B, the yeast is worthless, and if any gas be found in C, the yeast itself has given off C02. In the last two cases the process must be repeated with a new sample of yeast. Quantitative Determination of Glucose.—(1.) By the polarimeter.— The filtered urine is observed by the polariscope (see p. 38) and the mean of half a dozen readings taken as the angle of deviation ; from this the percentage of sugar is determined by the formula p = ro-^_— „ in which X L p = the weight, in grams, of glucose in 1 c.c. of urine ; a = the angle of deviation ; l = the length of the tube in decimeters. The same formula may be used for other substances by substituting for 52.85 the value of [ o]n for that substance. If the urine contain albumen, it must be removed be- fore determining the value of a. (2.) By specific gravity; Bobert’s method.—The sp. gr. of the urine is carefully determined at 25° (77° F.); yeast is then added, and the mixture GLUCOSES. 221 kept at 25° (77° F.) until fermentation is complete ; the sp. gr. is again observed, and will be found to be lower than before. Each degree of dim- inution represents 0.2196 gram of sugar in 100 c.c. (1 grain per ounce) of urine. (3.) By Fehling’s solution.—Of the many formulae for Fehling’s solu- tions, the one to which we give the preference is that of Dr. Pifiard. Two solutions are required : I. Cupric sulphate (pure, crystals) 51.98 crams. Water 500.0 c.c. II. Rochelle salt (pure, crystals) 259.9 grams. Sodic hydrate solution, sp. gr. 1.12 1000.0 c.c. When required for use, one volume of No. I. is mixed with two vol- umes of No. II. The copper contained in 20 c.c. of this mixture is pre- cipitated as cuprous oxide by 0.1 gram glucose. To use the solution, 20 c.c. of the mixed solutions are placed in a flask of 250-300 c.c. capacity, 40 c.c. of distilled water are added, the whole thoroughly mixed and heated to boiling. On the other hand, the urine to be tested is diluted with four times its volume of water if poor in su- gar, and with nine times its volume if highly saccharine (the degree of di- lution required is, with a little practice, determined by the appearance of the deposit obtained in the qualitative testing); the water and urine are thoroughly mixed and a burette filled with the mixture. A few drops of aqua ammonia? are added to the Feliling’s solution and the diluted urine added, in small portions toward the end, until the blue color is entirely discharged—the contents of the flask being made to boil briskly between each addition from the burette. When the liquid in the flask shows no blue color, when looked through with a white background, the reading of the burette is taken ; this reading, divided by five if the urine was diluted with four volumes of water, or by ten if with nine volumes, gives the num- ber of c.c. of urine containing 0.1 gram of glucose ; and consequently the elimination of glucose in twenty-four hours, in decigrams, is obtained by dividing the number of c.c. of urine in twenty-four hours by the result ob- tained above. Example.—20 c c. Fehling’s solution used, and urine diluted with four volumes of water. 36.5 Reading of burette : 36.5 c.c. —■=—= 7.3 c.c. urine contain 0.1 gram o glucose. Patient is passing 2,436 c.c. urine in twenty-four hours. 2 436 333.6 decigr. = 33.36 grams glucose in twenty-four hours. 1.0 The accuracy of the determination may be controlled by filtering off some of the fluid from the flask at the end of the reaction ; a portion of the filtrate is acidulated with acetic acid and treated with potassium fer- rocyanide solution; if it turn reddish brown the reduction has not been complete, and the result is affected with a plus error. To another portion of the filtrate a few drops of cupric sulphate solution are added and the mixture boiled ; if any precipitation of cuprous oxide be observed, an ex- cess of urine has been added, and the result obtained is less than the true one. This method, when carefully conducted with accurately prepared and 222 MANUAL OF CHEMISTRY. undeteriorated solutions, is the best adapted to clinical uses. The copper solution should be kept in the dark, in a well-closed bottle, and the stopper and neck of the No. II. bottle should be well coated with paraffin. (4.) Gravimetric method.—When more accurate results than are ob- tainable by Fehling’s volumetric process are desired, recourse must be had to a determination of the weight of cuprous oxide obtained by reduction. A small quantity of freshly prepared Fehling’s solution is heated to boil- ing in a small flask ; to it is gradually added, with the precautions ob- served in the volumetric method, a known volume of urine, such that at the end of the reduction there shall remain an excess of unreduced copper salt. The flask is now completely filled with boiling H„0, corked, and al- lowed to cool. The alkaline fluid is separated as rapidly as possible from the precipitated oxide, by decantation and filtration through a small double filter, and the precipitate and flask repeatedly washed with hot H.,0 until the washings are no longer alkaline ; a small portion of the precipitate re- mains adhering to the walls of the flask. The filter and its contents are dried and burned in a weighed porcelain crucible ; when this has cooled, the flask is rinsed out with a small quantity of N03H ; this is added to the contents of the crucible, evaporated over the water-bath, the crucible slowly heated to redness, cooled, and weighed ; the difference between this last weight and that of the crucible -f- that of the filter ash, is the weight of cupric oxide, of which 220 parts = 100 parts of glucose. Laevulose—■Uncrystallizable sugar—forms the uncrystallizable por- tion of the sugar of fruits and of honey, in which it is associated with glucose ; it is also produced artificially by the prolonged action of boiling water upon inulin ; and as one of the constituents of inverted sugar. Laevulose is not capable of crystallization, but may be obtained as a thick syrup ; very soluble in water, insoluble in absolute alcohol ; it is sweeter but less readily fermentable than glucose, which it equals in the readiness with which it reduces cupro-potassic solutions. Its prominent physical property, and that to which it owes its name, is its strong left- handed polarization, [a]D= —106° at 15° (593F.). At 170° (338° F.) it is converted into the solid, amorphous Icevulosan, C6H10O5. Mannitose—is obtained by the oxidation of mannite. It is a yellow, uncrystallizable sugar, having many of the characters of glucose, but opti- cally inactive. Galactose—sometimes improperly called lactose—is formed by the action of dilute acids upon lactose (milk sugar) as glucose is formed from saccharose. It differs from glucose in crystallizing more readily, in being very sparingly soluble in cold alcohol, in its action upon polarized light, [a]„ = +83°.33, and in being oxidized to mucic acid by NOsH. Inosite—Muscle-sugar—exists in the liquid of muscular tissue, in the lungs, kidneys, liver, spleen, brain, and blood ; pathologically in the urine in Bright’s, diabetes, and after the use of drastics in uraemia, and in the contents of hydatid cysts ; also in the seeds and leaves of certain plants. What the source and function of inosite in the animal economy may be is still a matter of conjecture. It forms long, colorless, monoclinic crystals, containing 2 Aq., usually arranged in groups having a cauliflower-like appearance. It effloresces in dry air ; has a distinctly sweet taste ; is easily soluble in water, difficultly in alcohol; insoluble in absolute alcohol and in ether ; it is without action upon polarized light. The position of inosite in this series is based entirely upon its chem- ical composition, as it does not possess the other characteristics of the SACCHAROSES. 223 group. It does not enter directly into alcoholic fermentation, although upon contact with putrefying animal matters it produces lactic and butyric acids ; -when boiled with barium or potassium hydrate, it is not even col- ored ; in the presence of inosite, potash precipitates with cupric sulphate solution, the precipitate being redissolved in an excess of potash ; but no reduction takes place upon boiling the blue solution. The presence of inosite is indicated by the following reactions: Scherer's. —Treated with N03H, the solution evaporated to near dryness, and the residue moistened with ammonium hydrate and calcium chloride, and again evaporated ; a rose-pink color is produced. Succeeds only with nearly pure inosite. Gallois’.—Mercuric nitrate produces, in solutions of inosite, a yellow precipitate, which, on cautious heating, turns red ; the color dis- appears on cooling, and reappears on heating. Saccharoses, C12H2aOH—342. Saccharose—Cane-sugar—Beet-sugar—Saccharum (U S.)—The most important member of the group, exists in many roots, fruits, and grasses, and is produced from the sugar-cane, saccharum officinarum, sorghum, sorghum saccharatum, beet, beta vulgaris, and sugar-maple, acer saccha- rinum. For the extraction of sugar the expressed juice is heated in large pans to about 100° (212° F.) ; milk of lime is added, which causes the precipi- tation of albumen, wax, calcic phosphate, etc.; the clear liquid is drawn off, and “ delimed ” by passing a current of C02 through it; the clear liquid is again drawn off and evaporated, during agitation, to the crystal- lizing-point ; the product is drained, leaving what is termed raw or mus- covado sugar, while the liquor which drains off is molasses. The sugar so obtained is purified by the process of “ refining,” which consists essentially in adding to the raw sugar, in solution, albumen in some form, which is then coagulated, filtering first through canvas, afterward through animal charcoal; the clear liquid is evaporated in “ vacuum-pans,” at a temper- ature not exceeding 72° (161°. 6 F.), to the crystallizing-point. The pro- duct is allowed to crystallize in earthen moulds ; a saturated solution of pure sugar is poured upon the crystalline mass in order to displace the uncrystallizable sugar which still remains ; and the loaf is finally dried in an oven. The liquid displaced as above is what is known as sugar-house syrup. Pure sugar should be entirely soluble in water ; the solution should not turn brown when warmed with dilute potassium hydrate solution ; should not reduce Fehling’s solution, and should give no precipitate with ammo- nium oxalate. Beet-sugar is the same as cane-sugar, except that, as usually met with in commerce, it is lighter, bulk for bulk. Sugar-candy, or rocTc-candy, is cane-sugar allowed to crystallize slowly from a concentrated solution with- out agitation. Maple-sugar is a partially refined, but not decolorized va- riety of cane sugar. Saccharose crystallizes in small, white, monoclinic prisms ; or, as sugar- candy, in large, yellowish, transparent crystals ; sp. gr. 1.606. It is very soluble in water, dissolving in about one-third its weight of cold water, and more abundantly in hot water. It is insoluble in absolute alcohol or ether, and its solubility in water is progressively diminished by the addi- 224 MANUAL OF CHEMISTRY. tion of alcoliol. Aqueous solutions of cane-sugar are dextrogvrous, ty]u = + 73°.8. When saccharose is heated to 1G0° (320° F.) it fuses, and the liquid, on cooling, solidifies to a yellow, transparent, amorphous mass, known as barley-sugar ; at a slightly higher temperature, it is decomposed into glu- cose and lnevulosan ; at a still higher temperature, HaO is given oft', and the glucose already formed is converted into glucosan ; at 210° (410° F.) the evolution of H20 is more abundant, and there remains a brown material known as caramel, or burnt sugar; a tasteless substance, insoluble in strong alcohol, but soluble in H20 or aqueous alcohol, and used to com- municate color to spirits ; finally, at higher temperatures, methyl hydride and the two oxides of carbon are given off; a brown oil, acetone, acetic acid, and aldehyde distil over ; and a carbonaceous residue remains. If saccharose be boiled for some time with H„0, it is converted into inverted sugar, which is a mixtui’e of glucose and laevulose: + H„0 — CeHI208 4- C6II]O0c. With a solution of saccharose the polarization is dextrogyrous, but, after invertion, it becomes lsevogyrous, because the left handed action of the molecule of kevulose produced, [a]D= —106,° is only partly neutralized by the right-handed action of the glucose, [ajn — + 52°.85. This inversion of cane-sugar is utilized in the testing of samples of sugar. On the other hand, it is to avoid its occurrence, and the conse- quent loss of sugar, that the vacuum-pan is used in refining—its object be- ing to remove the H„0 at a low temperature. Those acids which are not oxidizing agents act upon saccharose in three ways, according to circumstances: (1) if tartaric and other organic acids be heated for some time with saccharose to 100°—120° (212°-248° F.), compounds known as saccharides, and having the constitution of ethers, are formed ; (2) heated with mineral acids, even dilute, and less rapidly with some organic acids, saccharose is quickly converted into in- verted sugar ; (3) concentrated acids decompose cane-sugar entirety, more rapidly when heated than in the cold ; with HC1, formic acid and a brown, flocculent material (ulmic acid ?) are formed; with S04H2, S02 and H20 are formed, and a voluminous mass of charcoal remains. Oxalic acid, aided by heat, produces C02, formic acid, and a brown substance (humine ?). Oxidizing agents act energetically upon cane-sugar, which is a good reducing agent. With potassium chlorate, sugar forms a mixture which detonates when subjected to shock, and which deflagrates when moistened with S04H2. Dilute NOsH, when heated with saccharose, oxidizes it to saccharic and oxalic acids. Concentrated NOaH, alone or mixed with S04H3, converts it into the explosive nitro-saccharose. Potassium per- manganate, in acid solution, oxidizes it completely to C02 and H20. Cane-sugar reduces the compounds of Ag, Hg and Au, when heated with their solutions ; it does not reduce the cupro-potassic solutions in the cold, but effects their reduction when heated with them to an extent pro- portional to the amount of excess of alkali present. When moderately heated with liquor potassse, cane-sugar does not turn brown, as does glucose; but by long ebullition it is decomposed by the alkalies much less readily than glucose, with formation of acids of the fatty series and oxalic acid. With the bases, saccharose forms definite compounds called sucrates (improperly saccharates, a name belonging to the salts of saccharic acid). With Ca it forms five compounds. Hydrate of calcium dissolves readily in solutions of sugar, with formation of a Ca compound, soluble in H20, AMYLOSES. 225 containing an excess of sugar. A solution containing 100 parts of sugar in 600 parts of H,0 dissolves 32 parts of calcic oxide. These solutions have an alkaline taste ; are decomposed, with formation of a gelatinous precipitate, when heated, and, with deposition of calcium carbonate and regeneration of saccharose, when treated with C02. Quantities of cal- cium sucrates are frequently introduced into sugars to increase their weight—an adulteration the less readily detected, as the sucrate dissolves with the sugar. Calcium sucrates exist in the liq. calcis saccharatus (Br.). Yeast causes fermentation of solutions of cane-sugar, but only after its conversion into glucose. Fermentation is also caused by exposing a solu- tion of sugar containing ammonium phosphate to the air. During the process of digestion, probably in the small intestine, cane- sugar is converted into glucose. Lactose—Milk-sugar—Lactine—Saccharum lactis (U. S., Br.)—has hitherto been found only in the milk of the mammalia. It may be ob- tained from skim-milk by coagulating the casein with a small quantity of SO.H2, filtering, evaporating, redissolving, decolorizing with animal char- coal, and recrystallizing. It forms prismatic crystals; sp. gr. 1.53 ; hard, transparent, faintly sweet, soluble in 6 parts of cold and in 2.5 parts of boiling H20 ; soluble in acetic acid ; insoluble in alcohol and in ether ; its solutions are dextro- gyrous, [a]D=+59°.3. The crystals, dried at 100° (212° F.), contain 1 Aq., which they lose at 150° (302° F.). Lactose is not altered by contact with air. Heated with dilute mineral or with strong organic acids, it is converted into galactose. NOsH oxidizes it to mucic and oxalic acids. A mixture of N03H and S04H„ converts it into an explosive nitro-compound. With organic acids it forms ethers. With soda, potash, and lime it forms compounds similar to those of sac- charose, from which lactose may be recovered by neutralization, unless they have been heated to 100° (212° F.), at which temperature they are decomposed. It reduces Fehling’s solution, and reacts with Trommer’s test. In the presence of yeast, lactose is capable of alcoholic fermentation, which takes place slowly, and, as it appears, without previous transforma- tion of the lactose into either glucose or galactose. On contact with putrefying albuminoids it enters into lactic fermentation. The average proportion of lactose in different milks is as follows : Cow, 5.5 per cent. ; mare, 5.5 ; ass, 5.8 ; human, 5.3 ; sheep, 4.2 ; goat, 4.0. When taken internally, it is converted into galactose by the pancreatic secretion ; wrhen injected into the blood, it does not appear in the urine, which, however, contains glucose. Maltose—A sugar closely resembling glucose in many of its proper- ties, is formed along with dextrine during the conversion of starch into sugar by the action of diastase and of the cryptolytes of the saliva and pancreatic juice. It crystallizes as does glucose, but differs from that sugar in being less soluble in alcohol and in exerting a dextrogyratory power three times as great. Amyloses, „(C6H10O5)—wl62. Starch—Amylum (U. S.)—the most important member of the group, exists in the roots, stems, and seeds of all plants. It is prepared from rice, wheat, potatoes, maniot, beans, sago, arrow-root, etc. The com- minuted vegetable tissue is steeped for a considerable time in H.20 ren- 226 MANUAL OF CHEMISTRY. dered faintly alkaline with soda ; the softened mass is then rubbed on a sieve under a current of water, which washes out the starch granules ; the washings are allowed to deposit the starch, which, after washing by de- cantation, is dried at a low temperature. Starch is a white powder, having a peculiar slippery feel, or it appears in short columnar masses. The granules of starch differ in size and appearance according to the kind of plant from which they have been ob- tained. They are rounded or egg-shaped masses, having at the centre or toward one end a spot, called the hilum, around which are a series of con- centric lines more or less well marked. Differences in size, shape, and markings of starch granules are shown in Fig. 39. Fig. 39. Starch is not altered by exposure to air, except that it absorbs moisture. Commercial starch contains 18 per cent, of H„0, of which it loses 8 per cent, in vacuo, and the remaining 10 per cent, at 145° (293° F.). It is insoluble in alcohol, ether and cold water. If 15 to 20 parts of H„0 be gradually heated with 1 part of starch, the granules swell at about 55° (131° F.), and at 80° (176° F.) they have reached 30 times their original dimensions ; their structure is no longer distinguishable, and they form a translucent, gelatinous mass, commonly known as starch AMYLOSES. 227 paste. In this state the starch is said to be hydrated, and, if boiled with much H20, and the liquid filtered, a solution of starch passes through, which is opalescent from the suspension in it of undissolved particles. Cold dilute solutions of the alkalies produce the same effects on starch as does hot water. Hydrated starch is dextrogyrous, [a]D = + 216°. Dry heat causes the granules of starch to swell and burst; at 200° (392° F.) it is converted into dextrin ; at 230° (446° F.) it forms a brownish-yellow, fused mass, composed principally of pyrodextrin. Hydrated starch is converted into dextrin by heating with Ho0 at 160° (320° F.), and, if the action be prolonged, the.new product is changed to glucose. The amount of starch contained in food vegetables varies from about 5 per cent, in turnips to 89 per cent, in rice, as will be observed in the following table : Nitrogen- j ized matter. Starch. Dextrin, etc. Cellu- lose. Fat. Mineral matter. Carbo- hydrate. Water. Vegetable fibre, etc. Authority. Wheat, hard. 22.75 58.02 9.50 3.50 2.61 3.02 Payen. Wheat, hard 111.50 65.07 7.60 3.0 2.12 2.71 Payen. Wheat, hard 2U.0 63.80 8.0 3.10 2.25 2.85 Payen. Wheat, semi-hard.. 15.25 70.05 7.0 3.0 1.95 2.75 Payen. Wheat, soft 12.05 70.51 6.C5 2.80 1.87 2.12 Payen. Rye 12.50 04.05 14.90 3.10 2.25 2.60 Payen. Rarley 12.90 06.43 10.0 4.75 2 76 3.10 Payen. Oats 11x9 60.59 9.25 7.06 5.50 3.25 Payen. Maize 12.50 f>7.f 5 4.0 5.90 8.80 1.25 Payen. Rice 7.55 88.65 1.0 1.10 0.80 0.90 Payen. Flour 14.45 1.25 1.60 68.48 14.22 Payen. Flour 10.80 2.0 1.70 70.50 15.0 Letheby. Bread 8 10 1.60 2.30 51.CO 37.0 Letheby. Oatmeal 12.00 5.60 3.0 63.80 15.0 Letheby. Buckwheat 18.10 64.90 3.50 3.0 2.50 13.0 Payen. Quinoa seeds 22.86 56.80 5.74 5.05 9.53 Voelcker. Quinoa flour 19.0 60.0 5.0 16.0 Voelcker. Horse-bean 30.80 48.30 3.6 1.90 3.50 12 50 Payen. Broad bean 29 65 55.85 1.05 2.0 3.65 8.40 Payen. White bean 25.50 65.70 2.09 2.80 3.20 9.90 Payen. Peas, dried 23.80 58.70 3.50 2.10 2.10 8.30 Paven. Lentils Potato 25.20 2.50 56.0 20.0 L09 2.40 1.04 2.60 0.11 2.30 1.26 11.50 74.0 Payen. Payen. Potato 2.10 18.80 3.20 0.20 0.70 75.0 Letheby. Sweet potato 1.50 16.05 10.20 6.45 0 30 2.60 67.50 i.io Payen. Carrots 1.30 8.40 6.10 0.20 1.0 83.0 Letheby. Parsnip 1.10 9.00 5.80 0.50 1.0 82.0 Letheby. Turnip 1.20 5.10 2.10 0.60 91.0 Letheby. Composition of Vegetable Foods. If starch be ground up with dilute S04H„ after about half an hour the mixture gives only a violet color with I (see below) ; if now the acid be neutralized with chalk and the filtered liquid evaporated, it yields a white, granular product, which differs from starch in being soluble in H.,0, especially at 50° (122° F.), and in having a lower rotary power, [a]„ = -f 211°. If the action be prolonged, the value of [a]D continues to sink until it reaches 4-73.7°, when the product consists of a mixture of dextrin and glucose. Concentrated N03H dissolves starch in the cold, forming a nitro-product called xylodin or pyroxam, which is insoluble in H„0, sol- uble in a mixture of alcohol and ether; explosive. HC1 and oxalic acid convert starch into glucose. "When starch is heated under pressure to 120° (248° F.) with stearic or acetic acid, compounds are formed which seem to be ethers, and to indicate that starch is the hydrate of a trivalent, oxygen- ated radical, (CcH7O0)'". Potash and soda in dilute solution convert starch into the soluble modification mentioned above. 228 MANUAL OF CHEMISTRY. A dilute solution of I produces a more or less intense blue-violet color with starch, either dry, hydrated, or in solution, the color disappearing on the application of heat, and returning on cooling. If to a solution of starch, blued by I, a solution of a neutral salt be added, there separates a blue, ilocculent deposit of the so-called iodide of starch. Iodine renders starch soluble in water, and a soluble iodized starch, Amylum iodatum (U. S. ), is obtained by triturating together 19pts. starch, 2 pts. water, and 1 pt. iodine, and drying below 40° (104° F.). Starch has not been found in the animal economy outside of the ali- mentary canal, in which, as a prerequisite to its absorption, it must be converted into dextrin and glucose. This change is partially effected by the action of the saliva ; more rapidly with hydrated than with dry starch, and more rapidly with the saliva of some animals than that of others ; those of man and of the rabbit acting much more quickly than those of the horse and dog. A great part of the starch taken with the food passes into the small intestine unchanged ; here, under the influence of a pancreatic crvp- tolyte, a further transformation into glucose, and of a portion into lactic and butyric acids, takes place. Glycogen occurs in the liver, the placenta, white blood-corpuscles, pus-cells, young cartilage-cells, in many embyronic tissues, and in muscu- lar tissue. During the activity of muscles the amount of glycogen which they contain is diminished, and that of sugar increased. Pure glycogen is a snow-white, floury powder; amorphous, tasteless, and odorless ; soluble in H20, insoluble in alcohol and ether; in H20 it swells up at first, and forms an opalescent solution, which becomes clear on the addition of potash. Its solutions are dextrogyrous to about three times the extent of those of glucose. Dilute acids, ptyalin, pancreatin, extract of liver-tissue, blood, diastase, and albuminoids convert glycogen into a sugar having all the properties of glucose. Cold NO..H converts it into xyloidin ; on boiling, into oxalic acid. Its solutions dissolve cupric hydrate, which is, however, not reduced on boiling. Iodine colors glycogen wine red. Concerning the method of formation of glycogen in the economy, but little is known with certainty ; there is little room for doubting, however, that while the bulk of the glycogen found in the liver results from mod- ification of the carbohydrates, it may be and is produced from the al- buminoids as well. The ultimate fate of glycogen is undoubtedly its transformation into sugar under the influence of the many substances existing in the body capable of provoking that change. Dextrin—British gum—a substance resembling gum arabic in appear- ance and in many properties, is obtained by one of three methods : (1) by subjecting starch to a dry heat of 175° (347° F.); (2) by heating starch with dilute S04li2 to 90° (194° F.) until a drop of the liquid gives only a wine-red color ; neutralizing with chalk, filtering, concentrating, precipi- tating with alcohol; (3) by the action of diastase (infusion of malt) upon hydrated starch ; as soon as the starch is dissolved the liquid must be rapidly heated to boiling to prevent saccharification. Dextrin is a colorless, or yellowish, amorphous powder, soluble in H20 in all proportions, forming mucilaginous liquids ; when obtained by evap- oration of its solution, it forms masses resembling gum arabic in appear- ance. Dextrogyrous [a]D = + 138.88°. NO.II oxidizes it, not to mucic acid, as it does the gums, but to oxalic acid ; a mixture of N03H and S04H2 converts it into a dinitro-compound. It reduces the cupro-potassic solutions at 85° (185° F.). By iodine it is colored light wine-red. AMYLOSES. Dextrin lias been found to exist in the blood, lungs, and other organs of carnivora and herbivora, and in the contents of the intestine. Cellulose—Cellulin—Lignin—forms the basis of all vegetable tissues ; it exists, almost pure, in the pith of elder and of other plants, in the purer, unsized papers, in cotton, and in the silky appendages of certain seeds. Cotton, freed from extraneous matter by boiling with potash, and after- ward with dilute HC1, yields pure cellulose. It is a white material, having the shape of the vegetable structure from which it was obtained ; insoluble in the usual neutral solvents, but soluble in the deep blue liquid obtained by dissolving copper in ammonia in contact with air. Vegetable parchment, or parchment paper, is a tough material, possess- ing all the valuable properties of parchment, made by immersing unsized paper for an instant in moderately strong S04H2, washing thoroughly, and drying. Nitro-cellulose. By the action of NO.H upon cellulose (cotton) three different products of substitution may be obtained : mononitro-cellulose, soluble in acetic acid, insoluble in a mixture of ether and alcohol; dinitro- cellulose, insoluble in acetic acid, soluble in a mixture of ether and alcohol; trinitro-cellulose, soluble in both the above solvents. Gun-cotton or pyroxy- lin is composed of varying proportions of these three derivatives. When gun-cotton is required as an explosive agent, the process is so managed that the product shall contain the greatest possible proportion of trinitro- cellulose, the most readily inflammable of the three. When required for the preparation of collodion, for use in medicine or in photography, dinitro- cellulose is the most valuable. To obtain this, a mixture is made of equal weights of N03H and S04H2 (of each about 5 times the weight of the cot- ton to be treated); in this the cotton is immersed and well stirred for about three minutes, after which it is well stirred in a large vessel of water, washed with fresh portions of water until the washings are no longer pre- cipitated by barium chloride, and dried. Collodion is a solution of dinitro- cellulose in a mixture of three volumes of ether and one volume of alcohol. Gums—are substances of unknown constitution, existing in plants ; amorphous ; soluble in water, insoluble in alcohol; converted into glucose by boiling with dilute S04H2. Lichenin is»obtained from various lichens by extraction with boiling water, forming a jelly on cooling ; it is oxidized to oxalic acid by N03H ; is colored yellow by iodine ; and is precipitated from its solutions by alcohol. Arabin is the soluble portion of gum arabic and gum Senegal—Aca- cia (U. /S'.). To separate it, gum arabic is dissolved in water acidulated with HC1, and precipitated by alcohol. It is a white, amorphous, taste- less substance, which is not colored by iodine ; is oxidized by N03II to mucic and saccharic acids ; is converted by S04H2 into a non-fermentable sugar, arabinose ; and has the composition, C12H20O10+ 1 Aq. Bassorin constitutes the greater part of gum tragacanth ; it is insoluble in water, but swells up to a jelly in that fluid. Cerasin is an insoluble gum exuded by cherry- and plum-trees ; water acts upon it as upon bassorin. 230 MANUAL OF CHEMISTRY. FIFTH SERIES OF HYDROCARBONS. Series CnH3n_6. The hydrocarbons of this series are the starting-points from which the major part of that numerous and important class of substances usually classed as aromatic are obtainable or derivable. Those of the series at present known are: Benzene CBH6 boils at 80°.4 (176°. 7 F.) Toluene ..C7H8 boils at 110°.3 (230°. 5 F.) Xylene CSH10 boils at 142°.0 (287°. 6 F.) Cumene C9H]2 ... .boils at 151°.4 (304°. 5 F.) Cymene e10H14... .boils at 115°.0 (347°. 0 F.) Laurene CnH1{ boils at 188°.(I (370°. 4 F.) Benzene—Benzol—phenyl hydride—CRHR—78—(not to be confounded with the commercial benzine, a mixture of hydrocarbons of the series C,tII2n+2, obtained from petroleum) does not exist in nature, but is pro- duced in a number of reactions. It is obtained by one or two methods, according as it is required chemically pure or mixed with other sub- stances. To obtain it pure, recourse must be had to the decomposition of one of its derivatives, benzoic acid ; this substance is intimately mixed with 3 pts. slacked lime, and the mixture heated to dull redness in an earthen- ware retort, connected with a well-cooled receiver ; the upper layer of dis- tilled liquid is separated, shaken with potassium hydrate solution, again separated, dried by contact with fused calcium chloride, and redistilled over the water-batli. For use in the arts, and for most chemical purposes, benzene is ob- tained from coal- or gas-tar, an exceedingly complex mixture, containing some forty or fifty substances, among which are : Hydrocarbons. Acids. Bases. Benzene, Toluene. Xylene. Cumene. Cymene. Naphthalene. Acenaphthalene. Fluorene. Anthracene. Retene. Chrysene. Pyrene. Carbolic. Cresylic. Phlorylic. Rosolie. Oxyphenic. Pyridine. Aniline. Picoline. Lutidine. Collidine. Leucoline. Iridoline. Cryptidine. Acridine. Coridine. Rubidiue. Yiridine. By a primary distillation of coal-tar the most volatile constituents, in- cluding benzene, are separated as light oil; this is washed, first with SO(H.,, and then with caustic soda, and afterward redistilled ; that portion being collected which passes between 80° and 85° (lTO0-!^3 F.). This is the commercial benzene, a product still contaminated with the higher liomologues of the same series, from which it is almost impossible to separate it, but whose presence is rather advantageous than otherwise to the principal use to which benzol is put—the manufacture of aniline dyes. Benzene is a colorless, mobile liquid, having, when pure, an agreeable odor; sp. gr. 0.86 at 15° (59° F.) ; crystallizing at +4°. 5 (40°. 1 F.) ; boiling at 80°.5 (176°.9 F.) ; very sparingly soluble in water, soluble in alcohol, ether, and acetone. It dissolves I, S, P, resins, caoutchouc, gutta- percha, and almost all the alkaloids. It is inflammable, and burns with a luminous, smoky flame. Benzene unites with Cl or Br to form products of addition, or of sub- stitution ; the corresponding iodine compounds can only be obtained by indirect methods. Sulphuric acid combines with benzene to form a neu- FIFTH SERIES OF HYDROCARBONS. 231 tral substance, sulpho-benzide, when the anhydrous acid is used, and phenyl- sulphurous acid with the ordinary S04H2. If fuming N03H of sp. gr. 1.52 be slowly added to benzene, a reddish liquid is formed ; from which, on the addition of H20, a reddish-yellow oil separates, and is purified by washing with 11„0 and with sodium car- bonate solution, drying and rectifying. This oily material is mononitro- benzene (see p. 233). If benzol be boiled with fuming N03H, or if it be dropped into a mixture of N03H and S04II2, so long as the fluids mix, a crystalline product, dinitro-benzene, is formed. The constitution of benzene, the nucleus of the aromatic compounds, differs in character from that of the hydrocarbons of the series hitherto considered, and is of importance in connection with the formation of its numerous derivatives. Writing the molecular formulae of the sixth of each of the first three series (the constitution of those of the terebentliene series is still doubtful) we have: First Series. c = h3 I c = h2 I c = h2 I c = h2 I C = H, I c=h3 C6H14 Second Series. CeeII3 I C = H2 C = H2 I C = Ha I C- II II c = h2 c6h„ Third Series. c = h3 I C = H„ I c = h3 I c = n, I c in C-H c6h10 It will be observed that in each of these the chain of C atoms is an open one, and that the series differ in this, that in the first each of the C atoms exchanges with its neighbor a single valence ; in the second two neighboring C atoms exchange two valences between them ; and that in the third there is an exchange of three valences between two neighboring C atoms. And, further, that in terms above the second in the first two series, and the third in the third series, superior homologues may be considered as formed by interpolation of CH2 in the chain of the one next below. In the case of benzene the C atoms are arranged, not in an open, but a closed chain, and exchange with each other alternately one and two va- lences, and consequently the molecular formula of benzol is : H vV i ii /C c H \c/ H I H The superior homologues of benzene are derived from it by the sub- stitution of CH3 for H, and all the derivatives of benzol are formed by 232 MANUAL OF CHEMISTRY. such substitution of a group or groups for an atom or atoms of H, in such a way that they all contain one or more groups of six atoms of C arranged as above : H I H-C C-CeeH3 I II H-C C—H \C/ I H H ! H-C C—O—H I II H—C C—H \c/ I H Toluene. Phenol (carbolic acid). H I H—C C—(NOa)' I II H—C C—H \c/ I H H I H—C C—(NH2)' I II H—C C—H \c/ I H Nitro-benzene. Amido-benzene (aniline). Toluene—Toluol—Methyl-benzene—C6H5,CH3—92— exists in the pro- ducts of distillation of wood, coal, etc., and as one of the constituents of commercial benzene. It has been formed synthetically by acting upon a mixture of monobromo-benzene and methyl iodide with sodium. It is a colorless liquid, having a peculiar odor, differing somewhat from that of benzene ; boils at 110°.3 (230°.5 F.) ; does not solidify at —20° (—4° F.) ; sp. gr. 0.872 at 15° (59° F.) ; almost insoluble in water, solu- ble in alcohol, ether, carbon disulphide. It burns with a bright, but very smoky flame. It yields a number of derivatives similar to those of ben- zene, among which may be mentioned nitro-toluene and toluidine, the ho- mologues of nitro-benzene and aniline, which accompany those substances in the commercial products ; cresylol, the superior homologue of carbolic acid, and benzylic alcohol. Xylene—Xylol—Dimethyl-benzene— C6H4(CH3)3 —106 — accompanies its inferior homologues in coal-tar. When pure it is a liquid of an aro- matic odor; sp. gi*. 0.865 at 20° (68° F.) ; boils at 142° (287°.6 F.); insoluble in water, soluble in ether, benzene, etc., sparingly soluble in alcohol. There are three isomeric substances having this composition, and differing in the position in which the substituted CHS groups are placed. Each of these corresponds to a series of derivatives parallel to those of benzene. Cumene—Cumol—Propyl-benzene—CBH6(C3H7)—120—is obtained by distilling a mixture of cuminic acid and lime, as benzene is prepared from benzoic acid. It is a limpid liquid, having a strong aromatic odor ; PHENOLS. 233 boils at 151°.4 (304°.5 F.) ; insoluble in II„0, very soluble in alcohol and ether. There are several isomeres of this substance, among which are pseudo- cumene, or trimethyl-benzene, C6H3 (CH3)3, and mesitylene, or methyl-ethyl- benzene, C6H4 (CH3)(C,,Hr) ; each corresponding to a series of derivatives. Cymene—Cymol.—There are many isomeres, of which one exists ready formed in essence of cumin, and in hemlock. It is a colorless, oily liquid ; has an odor of lemon ; sp. gr. 0.857 at 16° (60°.8 F.) ; boils at 175° (347° F.) ; insoluble in wrater, but readily soluble in alcohol, ether, and essential oils. Nitro-benzol — Nitro benzene — Mono-nitro-benzene — Essence of Mir- bane—CrH.(NO„) —123—is obtained by the moderated action of fuming NOsH, or ot mixture of OincT S04II2) on benzol. It is a yellow, sweet liquid, with an odor of bitter almonds ; sp. gr. 1 209 at 15° (59° F.); boils at 213° (415°.4 F.); almost insoluble in water ; very soluble in alcohol and ether. Concentrated S04H2 dissolves, and, when boiling, decomposes it. Boiled with fuming N03H, it is converted into binitro-benzol. It is converted into aniline by reducing agents. It has been used in perfumery as artificial essence of bitter almonds ; but as inhalation of its vapor, even largely diluted with air, causes headache, drowsiness, difficulty of respiration, cardiac irregularity, loss of muscular power, convulsions, and coma, its use for that purpose is to be condemned. Taken internally it is an active poison. Nitro-benzol may be distinguished from oil of bitter almonds (benzoic aldehyde) by S04H2, which does not color the former ; and by the action of acetic acid and iron filings, which convert nitro-benzol into aniline, whose presence is detected by the reactions for that substance (q. v.). PHENOLS. The hydrocarbons of the benzene series, unlike those previously con- sidered, form two distinct kinds of hydrates, differing from each other materially in their properties. The terms of one of these series exhibit all the functions of the alcohols, and are known as aromatic alcohols. The terms of the other series differ in function from any substance thus far considered, and are known as phenols. The difference between them and the aromatic alcohols is due to the fact that in the phenols the OH is directly attached to a C atom, while in the alcohols it forms part of the group of atoms CH2OH, characteristic of the alcohols : H A H—C C-CH3 I II H—C C—OH \C/ I H H I H—C C—CH2OH I II H—C C—H \C/ I H Benzylic Phenol. Benzylic alcohol. The phenols differ from the alcohols in not furnishing by oxidation corresponding aldehydes and acids ; in not dividing into water and hydro- 234 MANUAL OF CHEMISTRY. carbon under the influence of dehydrating agents ; in not reacting with acids to form ethers ; in combining to form directly products of substitu- tion with Cl and Br ; and in forming with metallic elements compounds more stable than similar compounds of the true alcohols. In short, the phenols appear to have, besides an alcoholic function, more or less of the function of acids. Phenol—Phenyl hydrate—Phenic acid—Carbolic acid—Acidum carboli- cum (U. 8, Br.)—CfH OH —94—exists in considerable quantity in coal- and wood-tar, and in small quantity in castoreum, and possibly in urine. It is formed : (1) by fusing sodium phenylsulpliide with an excess of alkali; (2) by heating phenyl iodide with potassium hydrate to 320° (608° F.) ; (3) by heating together salicylic acid and quicklime ; (4) by total synthesis from acetylene ; (5) by dry distillation of benzoin. The source from which it is obtained is that portion of the product of distillation of coal-tar which passes over between 150° and 200° (302°- 392° F.). This is treated with a saturated solution of potash containing undissolved alkali; a solid phenate is formed, which is dissolved in hot II20 ; the liquid is allowed to separate into two layers, the lower of which is drawn off and neutralized with HC1; the phenol rises to the surface, is separated, washed Avith Avater, dried OArer calcium chloride, redistilled, crystallized at —10° (14° F.), and the crystals drained. Pure phenol crystallizes in long, colorless, prismatic needles, fusible at 35° (95° F.), boiling at 187° (368kG F.). It has a peculiar, well-known odor, and an acrid, burning taste ; very sparingly soluble in water, readily soluble in alcohol and in ether; sp. gr. 1.065 at 18° (64°.4 F.) ; neutral in reaction. On contact Avith the skin or with mucous surfaces, it produces a white stain ; it coagulates albuminoids, and is a powerful antiseptic. It may be distilled without decomposition. It absorbs H.,0 from damp air to form a hydrate, which crystallizes in six-sided prisms, fusible at 16° (60°.8 F.). Its vapor is reduced to benzene when heated Avith Zn. It combines with S04H2 to form phenylsulphuric acids. It forms trinitro- phenic acid (q. v.) with NOJ4 of 36° B. When hearted with S04H2 and oxalic acid it forms rosolic acid or corallin, which is a mixture from which the pigments aurw, peonin, azulin, and phenicin are obtained. Analytical Characters.—(1.) Its peculiar odor. (2.) A yelloAv color or ppt. with NOsH of 36° B. (3.) A blue or green color Avith a small quantity of NH4HO and a trace of a hypochlorite. (4.) A lilac color with a small quantity of ferric sulphate. (5.) A yellowish-white ppt. with bromine Avater. Toxicology.—When taken internally, phenol is an active poison, and one Avhose use by suicides has become quite common. "Vyhen it has been taken the mouth is whitened by its caustic action, and there is a marked odor of carbolic acid in the breath. It is eliminated by the urine, partly unchanged, and partly in the form of colored derivatives, which color the urine greenish, brownish, or even black. The treatment consists in the administration of albumen (Avliite of egg) and of emetics. To detect phenol in the urine, that liquor must not be distilled with S04H2, as sometimes recommended, as it contains normally substances which by such treatment yield carbolic acid. The best method consists in adding an excess of bromine water to about 500 c.c. (1 pint) of the urine ; on standing some hours, a yelloAAdsli precipitate collects at the bottom of the vessel; this is removed, washed, and treated Avith sodium amalgam, Avhen the characteristic odor of phenol is developed. From other parts of PHENOLS. 235 the body, phenol may be recovered by acidulating with tartaric acid ; dis- tilling ; extracting the distillate by shaking with ether; evaporating the ethereal solution ; extracting the residue with a small quantity of water, and applying to this solution the tests described above. Trinitrophenol—Picric acid—Trinitrophenic acid—C,H, (N0o)a0H —229—is derived from phenol by the substitution of three groups (NO,,) for three atoms of hydrogen. It crystallizes in brilliant, yellow, rectan- gular plates, or in six-sided prisms; it is odorless, and has an intensely bitter taste, whence its name (from wiKpos = bitter) ; it is acid in reaction ; sparingly soluble in water, very soluble in alcohol, ether, and benzene ; it fuses at 122°.5 (252°.5 F.), and may, if heated with caution, be sublimed unchanged ; but, if heated suddenly or in quantity, it explodes with violence. It behaves as a monobasic acid, forming salts, which are for the most part soluble, yellow, crystalline, and decompose with explosion when heated. Analytical Chabacters.—(1.) Its intensely bitter taste. (2.) Its alcoholic solution, when shaken with a potassium salt, gives a yellow crystalline ppt. (3.) An ammoniacal solution of cupric sulphate gives *a green, crystal- line ppt. (4.) Glucose heated with a dilute alkaline solution of picric acid, communicates to it a blood-red color. (5.) Warmed with an alkaline solution of potassium cyanide, an in- tense red color is produced (the same effect is produced by ammonium sulphydrate). (6.) Unbleached wTool, immersed in boiling solution of picric acid, is dyed yellow. Nos. 1, 3, 5 and 6 are quite delicate. When taken internally in overdose, it acts as a poison : it may be separated from animal fluids or from beer by evaporation to a syrup, ex- tracting with 95 per cent, alcohol, acidulated with S04H2; filtering; evaporating ; and applying the tests to a solution of the residue. Cresylol—Cresol—Cresylic acid—Benzylic phenol—Cresylic phenol— CPH, (CHJOH —108—accompanies phenol in coal- and wood-tars, from which it may be obtained by fractional distillation; it is more readily obtained pure from toluene. When pure it is a crystalline solid, fusible at 34°.5 (94°. 1 F.) ; as usually met with, however, it is a liquid, which does not solidify at —18° (—03.4 F.), and boils at 203° (397°.4 F.) ; it has an odor of creasote. Its properties, decompositions, and products resemble those of phenol. Creasote—Creasotum {U. S.)—is a complex mixture, containing phenol, cresylol, creasol, CHII10O„, and other substances, obtained from wood-tar, and formerly extensively used as an antiseptic. It is an oily liquid, color- less when freshly prepared, but becoming brownish on exposure to light; it has a burning taste and a strong, peculiar odor ; it boils at 203° (397°.4 F.), and does not solidify at —27° ( — 16°.6 F.). Crude phenol is often substituted for creasote ; the two substances may be distinguished by the following characters : Phenol. Creasote. Soluble in commercial glycerin. Precipitates nitro-cellulose from collodion. Gives a brown color with ferric chloride and alcohol Gives a violet color with ferric chloride and ammonium hydrate. Insoluble in commercial glycerin. Does not precipitate collodion. Gives a green color with ferric chloride and alcohol. Gives a green color, passing to brown, with ferric chloride and ammonium hydrate. 236 MANUAL OF CHEMISTRY. Xenols—Xylenols—CfH.(CH,)2OH—122.—Theoretically there are six possible xenols derivable from corresponding xylenes ; of these, four have been thus far obtained by the general methods of obtaining the phenols. None is of practical interest. Thymol—Cymylic phenol—CcH(CH3)4OH—150—exists, accompany- ing cymene and thymene, C10H16, in essence of thyme, from which it is ob- tained. The essence contains about one-half its weight of thymol, which is separated by agitation with a concentrated solution of caustic soda ; separation of the alkaline liquid, which is diluted and neutralized with HC1; thymol separates and is purified by rectification at 230° (446° F.). It crystallizes in large, transparent, rhombohedral tables ; has a pep- pery taste and an agreeable, aromatic odor; it fuses at 44° (111°.2 F.), and boils at 230° (446° F.) ; is sparingly soluble in water, very soluble in alcohol and ether; with the alkalies it forms definite compounds, which are very soluble in water. Its reactions are very similar to those of phenol. Thymol is an excellent disinfecting and antiseptic agent, and one of the best of embalming materials ; possessing the advantage over phenol of having itself a pleasant odor. AROMATIC ALCOHOLS. The alcohols corresponding to this series of hydrocarbons have the same composition as the corresponding phenols, from which they differ in con- stitution and in having the functions of true alcohols (see p. 116). Benzylic alcohol—Benzoic alcohol—Benzyl hydrate—C,H (CH,OH) —108—does not exist in nature, and is of interest chiefly as correspond- ing to two important compounds, benzoic acid and benzoic aldehyde (oil of bitter almonds). It is obtained by the action of potassium hydrate upon oil of bitter almonds, or by slowly adding sodium amalgam to a boiling solution of benzoic acid. It is a colorless liquid ; boils at 206°.5 (403°.7 F.) ; has an aromatic odor; is insoluble in water, soluble in all proportions in alcohol, ether, and carbon disulphide. By oxidation it yields, first, benzoic aldehyde, CcH6(COH) ; and afterward, benzoic acid, CrH6(COOH). By the same means it may be made to yield products similar to those obtained from the alcohols of the saturated hydrocarbons. DIATOMIC AROMATIC HYDRATES. There are three classes of these substances, viz.: Diatomic phenols, diatomic alcohols, and alphenols, which last are substances having a mixed function of alcohol and phenol, thus : H I C /\ H—C C—Oil II I H—C C—OH NX C I H H I C /\ H—C C—CH2OH 11 I H—C C—CH2OH NX C I H H i • /\ H—C C—CH.OH II I H—C C—OH NX C I H Hydroquinone (diatomic phenol). Toluyl glycol (diatomic alcohol). Saligenin (alphenol). ACIDS CORRESPONDING TO THE AROMATIC HYDRATES. 237 Hydroquinone—C6H602—110—forms transparent prisms ; fusible at 177°. 5 (351°.5 F.) ; obtained by the action of reducing agents on quinone, C6H4Oa ; itself a product of oxidation of quinic acid, C7Hia06, which oc- curs in cinchona bark. / CHaOH Saligenin, C6H4 —124—is an alphenol, i.e., a substance partly \OH alcohol (by the group CH,,OH) and partly phenol. It is obtained from salicin (q. v.) in large, tabular crystals ; quite soluble in alcohol, water, and ether. Oxidizing agents convert it into salicylic aldehyde, which by fur- ther oxidation yields salicylic acid. TRIATOMIC AROMATIC HYDRATES. The only compounds of this class at present known with certainty are two isomeric triatomic phenols, which probably owe the differences in properties existing between them to a different placing of the OH groups. They are phloroglucin and pyrogallol. Phloroglucin—C6H3 (OH) 3 —126—is obtained by the action of potash upon phloretin, quercitrin, maclurin (see Glucosides), catechin, kino, etc. It crystallizes in rhombic prisms, containing 2 Aq.; is very sweet; very sol- uble in water, alcohol, and ether. Pyrogallol—Pyrogallic acid—C6H3 (OH)3—126—is formed when gal- lic acid (q. v.) is heated to 200° (392° F.). It crystallizes in white needles ; neutral in reaction ; very soluble in water ; very bitter ; fuses at 115° (239° F.) ; boils at 210° (410° F.); poisonous. Its most valuable property is that of absorbing oxygen, for which purpose it is used in the laboratory in the form of a solution of potassium pyrogallate. ACIDS CORRESPONDING- TO THE AROMATIC HYDRATES. The acids, possibly derivable from benzene by the substitution of (COOH), or of (COOH) and (OH), for atoms of hydrogen, would form, were they all known, a great number of series ; there are, however, compar- atively few of them which have been as yet obtained, although the num- ber of acid series known is greater than that of corresponding alcohols. Each series of mono- and diatomic alcohols furnishes a corresponding series of acids ; thus : /CH2OH tl*\CH9OH H /CH2OH C„H6—CHaOH Benzoic alcohol. Saligenin. r tt /COOH U*\COOH Toluyl glycol. c tt /COOH C«i:L<\OH C6Hs-COOH There are still a number of other series of acids possibly derivable directly from benzene, without speaking of substituted acids of more com- plex nature ; of these, however, the majority are wanting. By the progressive substitution of groups (COOH) for atoms of hydro- Benzoic acid. Terephthalic acid. Salicylic acid. 238 MANUAL OF CIIEMISTKY. gen in benzene, we may obtain six series of acids, five of which have been isolated: C6H5(COOH) — C?1H2„_ 802 Benzoic series. Ct,H4(COOH)2—C„H,„_10O4 Phthalic series. C6H3(COOH)3—C„Hjn_J206 Triinellitic series. C6H2(COOH)4—CnH2n_1408 Prehnitic series. C6H(COOH)5 — CbH2„_16O10 Wanting. C6(COOH)6 — C„H3n_18012 Mellitic series. The alplienols, containing a single group (OH), are at present repre- sented by a single series: C6H4(OH)(COOH)—C„Hs„_80— Salicylic series. Corresponding to the unknown alplienols, containing a greater num- ber of (OH) groups, there are at present but two series of acids known : C6H3(OH)2(COOH)—CnH2„_80—Veratric series, and C6H2(OH)3(COOH)—C „H2„_8O6—Gallic series. In each of these series the basicity is, as usual, equal to the number of groups (COOH). Benzoic acid—Acidurn benzoicum (27. S.)—CfH.(COOH)—122— exists ready formed in benzoin, tolu balsam, castoreum, and several resins, It does not exist in animal nature, so far as is at present known ; in those situations in which it has been found, it has resulted from decomposition of hippuric acid (q. v.), or has been introduced from without. When taken in moderate doses, it does not pass out in its own form, but is con- verted into hippuric acid ; in excessive doses a portion is eliminated, unchanged in the urine. It is obtained from benzoin, or from the urine of herbivorous animals ; and is formed in a variety of reactions. It crystallizes in white, transparent plates ; odorless ; acid ; fuses at 122° (251°.6 F.); sublimes at 145° (293° F.); boils at 240° (464° F.); spar- ingly soluble in cold water ; soluble in hot water, alcohol, and ether. Dilute NOaH does not attack it. It dissolves in ordinary S04H2, and is precipitated unchanged by H,,0. Its salts are all soluble. Hippuric acid—Benzyl-glycocol—Benzyl-amido-aeetic acid—C.H NO., —179—is a constant constituent of the urine of the herbivora, and of human urine to the extent of 0.29-2.84 grams (4.5-43.8 grains) in 24 hours. It is more abundant with a purely vegetable diet, after the ad- ministration of benzoic acid, and in diabetes mellitus and chorea. It crystallizes in transparent, colorless, odorless, bitter prisms ; spar- ingly soluble in water; fuses at 130° (266° F.). It dissolves unchanged in HC1; but on boiling the solution it is decomposed into benzoic acid and glycocol. The same decomposition is effected by dilute S04H2, NO.,H, and oxalic acid, and by a ferment developed in putrefying urine. Oxidizing agents convert it into benzoic acid, benzamide, and C02. The characters of hippuric acid are : (1) when heated in a dry tube it fuses and gives off a sublimate of benzoic acid and an odor of hydrocyanic acid ; (2) it gives a brown ppt. with ferric chloride ; (3) when heated with lime it gives off benzine and ammonia. Salicylic Acid—Oxybenzoic acid—Acidurn salicylicum (27. S.)—CfH4 ALDEHYDES. (OH) COOK —138—was first obtained from essence of spircea, which con- sists largely of salicylic aldehyde, and subsequently from oil of winter- green (yaultheria), which contains methyl salicylate ; and also from salicine, a glucoside yielding salicylic aldehyde. It is now obtained from phenol. This is fused, and, while a current of dry C02 is passed through it, small portions of Na are added ; the sodium salicylate thus formed is dissolved in H,0 and decomposed with HC1, when the liberated salicylic acid is precipitated. It crystallizes in fine white needles ; very sparingly soluble in cold water, quite soluble in hot water, alcohol, and ether; it fuses at 158° (316°.4 F.), and maybe distilled with but slight decomposition, if it be pure. Cl and Br form with it products of substitution. Fuming N03H forms with it a nitro-derivative and, if the action be prolonged, converts it into picric acid. With ferric chloride, its aqueous solution assumes a fine violet color. Salicylic acid and its salts (it is monobasic, although diatomic) are extensively used in medicine, both externally as antiseptics and internally in the treatment of rheumatism, etc. It is not without caustic properties, and hence, when taken internally, it should be largely diluted. Gallic acid—Acidum gallicum (U. S.)—C0Ho (OH)3COOH—170— exists in nature in certain leaves, seeds, and fruits. It is best obtained from gall-nuts, which contain its glucoside, gallotannic acid (q. v.). It can be obtained from salicylic acid. It crystallizes in long, silky needles with 1 Aq. ; odorless ; acidulous in taste ; spai’ingly soluble in cold water, very soluble in hot water and in alcohol ; its solutions are acid. When heated to 210°-215° (410°-419° F.) it yields C02 and pyrogallol (q. v.). Its solution does not precipitate gelatin, nor the salts of the alkaloids, as does tannin. It forms four series of salts. ALDEHYDES. Benzoic aldehyde—Benzoyl hydride—C„H. (COH)—106—is the main constituent of oil of bitter almonds, although it does not exist in the almonds (see p. 248) ; it is formed, along with hydrocyanic acid and glu- cose, by the action of water upon amygdalin. It is also formed by a num- ber of general methods of producing aldehydes: by the dehydration of benzylic alcohol; by the dry distillation of a mixture in molecular pro- portions of calcium benzoate and formiate ; by the action of nascent hydrogen upon benzoyl cyanide, etc. It is obtained from bitter almonds. The crude oil contains, besides benzoic aldehyde, hydrocyanic and benzoic acids and cyanobenzoyl; to purify it, it is treated with three to four times its volume of a concen- trated solution of sodium bisulphite ; the crystalline mass is expressed, dissolved in a small quantity of water, and decomposed with a concen- trated solution of sodium carbonate—the treatment being repeated, if necessary. It is a colorless oil, having an acrid taste and the odor of bitter almonds ; sp. gr. 1.043 ; boils at 179°.4 (354°.9 F.) ; soluble in 30 parts of water, and in all proportions in alcohol and ether. Oxidizing agents convert it into benzoic acid, a change which occurs by mere exposure to air. Nascent hydrogen converts it into benzylic alcohol. With Cl and Br it forms benzoyl chloride or bromide. S04H9 dissolves it when heated, forming a purple-red color, which turns black if more strongly heated. 240 MANUAL OF CHEMISTRY. When perfectly pure, benzoic aldehyde exerts no deleterious action Avlien taken internally ; owing, however, to the difficulty of completely removing the hydrocyanic acid, the substances usually sold as oil of bitter almonds, ratafia, and almond flavor, are almost always poisonous, if taken in sufficient quantity. They may contain as much as 10-15 per cent, of hydrocyanic acid, although said to be “purified.” The presence of the poisonous substances may be detected by the tests given on page 246. Salicylic aldehyde—Salicyl hydride—Salicylol—Salicylous acid— CfH4 (OH) COH —122—exists in the flowers of spiraea ulmaria, and is the principal ingredient of the essential oil of that plant. It is best ob- tained by oxidizing salicine (q. v.). It is a colorless oil; turns red on exposure to air ; has an agreeable, aromatic odor, and a sharp, burning taste ; sp. gr. 1.173 at 13°.5 (56°.3 F.); boils at 196°.5 (385°.7 F.) ; soluble in water, more so in alcohol and ether. It is, as we should suspect from its origin, a substance of mixed func- tion, possessing the characteristic properties of aldehyde and phenol. It produces a great number of derivatives, some of which have the charac- ters of salts and ethers. AMINES. Phenylamines. Benzene may be considered as being made up of a radical group (C6H.)', united to hydrogen ; this radical is known as phenyl, and benzene is, therefor, phenyl hydride, as marsh-gas is methyl hydride. The radical, phenyl, is capable, like methyl, of replacing atoms of H of NH3 to form amines precisely similar in typical constitution to those of the univalent alcoholic radicals (see p. 143); or these amines may be considered as formed by the substitution of a group NH2 for an atom of H of one mole- cule of benzene, or of (NH)" for two atoms of H in two molecules, etc.: H I H—C C—NH, I II H—C C-H \c/ I H CH2(NH ,)' ch3 H H H I I I X°\ /N. C\ H-C C / N C C—H I II I II H—C C—H H—C C—H \c/ \c/ I I H H AMINES. 241 or typically: H H N ( N. H ) Analytical Characters.—(1.) With dry HC1 gas it turns reddish pur- ple, and then dark blue. (2.) Aqueous HC1 of sp. gr. 1.12 evaporated from coniine leaves a green-blue, crystalline mass. (3.) With iodic acid a white ppt. from alcoholic solutions. (4.) With S04H3 and evaporation of the acid : a red color, changing to green, and an odor of butyric acid. Nicotine—C10H14N3—162—exists in tobacco in the proportion of 2-8 per cent. It is a colorless, oily liquid, which turns brown on exposure to light and air; has a burning, caustic taste and a disagreeable, penetrating odor; it distils at 250° (392° F.) * it burns with a luminous flame ; sp. gr. 1.027 at 15° (59° F.) ; it is very soluble in water, alcohol, the fatty oils, and ether ; the last-named fluid removes it from its aqueous solution when the two are shaken together; it absorbs water rapidly from moist air. Its salts are deliquescent and crystallize with difficulty. 254 MANUAL OF CHEMISTRY. Analytical Characters.—(1.) Its ethereal solution, added to an ethereal solution of iodine, separates a reddish-brown, resinoid oil, which gradu- ally becomes crystalline. (2.) With HC1, a violet color. (3.) With N03H, an orange color. Both nicotine and coniine are actively poisonous, producing death by asphyxia, sometimes as rapidly as prussic acid. Fixed Alkaloids. These are much more numerous than those which are volatile, and form the active principles of a great number of poisonous plants. As we are yet in the dark as to the constitution of these bodies, the classification which we adopt is the temporary one, based upon the botanic characters of the plants from which they are derived. Opium Alkaloids. Opium is the inspissated juice of the capsules of the poppy. It is of exceedingly complex composition, and contains, besides a neutral body called meconin (probably a polyatomic alcohol, CUiH]oO,), a peculiar acid, meconic acid (q. v.), lactic acid, gum, albumen, wax, and a volatile matter —no less than eighteen different alkaloids, one or two of which, how- ever, are probably formed during the process of extraction, and do not pre-exist in opium. The following is a list of the constituents of opium, those marked * being of medical interest: Name. Formula. Percent, in Smyrna opium. Percent, in Constantino- ple opium. *Meconic acid.. C7H4O7 4.70 4.38 Lactic acid C3ILO3 1.25 .... Meconine. CioH, 0O4 0.08 0.30 * Morphine C17H19NO3 10.30 4.50 Pseudomorphine c17h19no4 Hydr ocotarnine. Ci 2H15NO3 * Codeine c18h21no3 0.25 1.52 *Thebaine c19h21no3 0.15 . • • • Protopine c20h1unob .... • • • • Rhasadine c2„h2,no6 .... Codamine C*0H4»NO4 Name. Formula. Percent, in Smyrna opium. Percent, in Constantino- ple opium. Laudanine C20H26NO4 Papaverine c2Ih21no4 1.00 • • • • Opianine C2 ] U2 j N 0 7 • - • • Meconidine.... c21h.23no4 .... Cryptopine..... C-2 i H03NO5 .... Laudanosine... c21h27no4 *Nareotine C22H23N07 1.30 3.47 Lanthopine c2Sh25no4 * Narceine CmH2BNOb 6.71 6.42 Porphyroxine... • • .... Morphine—Morphina (U. S.)—C]7H NO, + Aq—285 + 18—crystal- lizes in colorless prisms ; odorless, but very bitter ; it fuses at 120° (248° F.), losing its Aq. More strongly heated, it swells up, becomes carbon- ized, and finally burns. It is soluble in 1,000 pts. of cold water, in 100 pts. of boiling water ; in 20 pts. of alcohol of 0.82, and in 13 pts. of boil- ing alcohol of the same strength ; in 390 pts of cold amyl alcohol, much more soluble in the same liquid warm ; almost insoluble in aqueous ether; OPIUM ALKALOIDS. 255 rather more soluble in alcoholic ether ; almost insoluble in benzine ; soluble in 60 pts. of chloroform. All the solvents dissolve morphine more readily and more copiously when it is freshly precipitated from solutions of its salts than when it has assumed the crystalline form. Morphine combines with acids to form crystallizable salts, of which the chloride, sulphate, and acetate are used in medicine. If morphine be heated for some hours with excess of HC1, under pressure, to 150° (302° F.), it loses water and is converted into a new base—apomorphine, C]7HnN02—a valuable emetic, which may be administered hypodermically. It is a crystalline solid, soluble in ether. Analytical Characters—(1.) It is colored red, changing to yellow, by no3h. (2.) Cold, concentrated SO H , dissolves it, forming a colorless solution, which after 24 hours turns pink on addition of a trace of NO H; and the fluid when warmed, cooled, and diluted with H20, turns deep mahogany brown on the addition of a splinter of potassium dichromate. (3.) A mixture of morphine and cane sugar (1 to 4) added to concen- trated S04H2, gives a dark red color, which is intensified by a drop of bromine water. (4.) If iodic acid solution and a drop of chloroform be added to mor- phine, free iodine is liberated, which colors the chloroform violet. If now dilute NH HO iJe floated on the surface of the liquid, a dark brownish zone is formed. (5.) A neutral solution of a morphine salt gives a blue color with neutral solution of ferric chloride. (6.) A solution of molybdic acid in S04H2 (Frohde’s reagent) gives with morphine a violet color, changing to blue, dirty green and faint pink. Water discharges the color. (7.) Solution of morphine acetate produces a gray ppt. when warmed with ammoniacal silver nitrate solution ; and the filtrate turns red or pink with NO ,H. (8.) Auric chloride gives a yellow ppt., turning violet blue, with solu- tions of morphine salts. Codeine—Codeina (U. S.)—C18H21N03 + Aq—299 + 18—crystallizes in large rhombic prisms, or from ether, without Aq., in octahedra ; bitter ; soluble in 80 pts. cold water; 17 pts. boiling water; very soluble in alcohol, ether, chloroform, benzol; almost insoluble in petroleum ether. Analytical Characters.— (1.) Cold concentrated S04H2 forms with it a colorless solution, which turns blue after some days, or when warmed, (2.) Frohde’s reagent dissolves it with a dirty green color, which after a time turns blue. (3.) Chlorine water forms with it a colorless solution which turns yel- lowish red with NH4HO. Narceine—C23H29N09 + 2Aq—463 + 36—crystallizes in bitter, pris- matic needles ; sparingly soluble in water, alcohol, and amyl alcohol; in- soluble in ether, benzol, and petroleum ether. Analytical Characters.—(1.) Concentrated S04H2 dissolves it with a gray brown color, which changes to red, slowly at ordinary temperatures, rapidly when heated. (2.) Frohde’s reagent colors it dark olive green, passing to red after a time, or when heated. (3.) Iodine solution colors it blue violet, like starch. Narcotine—C2„H23N07— 413—crystallizes in transparent prisms, almost insoluble in water and in petroleum ether ; soluble in alcohol, ether, 256 MANUAL OF CHEMISTRY. benzol, and chloroform. Its salts are mostly uncrystallizable, unstable, and readily soluble in water and alcohol. Analytical Characters. — (1.) Concentrated S04H2 forms with it a solution, at first colorless, in a few moments yellow, and after a day or two, red. (2.) Its solution in dilute SO,H2, if gradually evaporated until the acid volatilizes, turns orange red, bluish violet, and reddish violet. (3.) Frohde’s reagent dissolves it with a greenish color, passing to cherry red. Thebaine — Paraviorphine — C H. NO,—311—crystallizes in white plates ; tasteless when pure ; insoluble in water ; soluble in alcohol, ether, and benzol. Analytical Characters.—(1.) With concentrated S04H2 an immediate bright red color, turning to yellowish red. (2.) Its solution in chlorine water turns reddish-brown with NH4HO. (3.) With Frohde’s reagent same as 1. Meconic acid—C7H407 + 3Aq—200 + 54—is a tribasic acid, peculiar to opium, in which it exists in combination with a part, at least, of the alkaloids. It crystallizes in small prismatic needles; acid and astringent in taste ; loses its Aq at 120° (248° F.); quite soluble in water; soluble in alcohol; sparingly soluble in ether. Analytical Characters.—With ferric chloride, a blood-red color, which is not discharged by dilute acids or by mercuric chloride ; but is discharged by stannous chloride and by the alkaline hypochlorites. Toxicology of Opium and its Derivatives.—Opium, its preparations and the alkaloids obtained from it are all active poisons. They produce drow- siness, stupor, slow and stertorous respiration, contraction of the pupil; small and irregular pulse, coma, and death. The symptoms set in from 10 minutes to 3 hours, sometimes immediately, sometimes only after 18 hours. Death has occurred in from 45 minutes to 3 days, usually in 5-18 hours. After 24 hours the prognosis is favorable. Death has been caused in an adult by one-lialf grain of acetate of morphia, while 30 grains a day have been taken by those accustomed to its use without ill effects. The alkaloids of opium have not the same action. In soporific action, beginning with the most powerful, they rank thus : Narceine, morphine, codeine ; in tetanizing action: thebaine, papaverine, narcotine, codeine, mor- phine ; in toxic action : thebaine, codeine, papaverine, narceine, morphine, narcotine. The treatment should consist in the removal of unabsorbed poison from the stomach by emesis and the stomach-pump, and washing out of the stomach after injection into it of powdered charcoal in suspension, or tea or coffee infusion. Cold affusions should be used and the patient kept awake. After death the reactions for meconic acid and narcotine permit of dis- tinguishing whether the poisoning was by opium or its preparations, or by morphine. Cinchona Alkaloids. Although by no means so complex as opium, cinchona bark contains a great number of substances : quinine, cinchonine, quinidine, cinchonidine, aricine; quinic, quinotannic, and quinovic acids; cinchona red, etc. Of these the most important are quinine and cinchonine. CINCHONA ALKALOIDS. 257 Quinine—Quinina (U. S.)—C20H24N2O2+n Aq.—324+nl8—exists in the bark of a variety of trees of the genera Cinchona and China, indigenous in the mountainous regions of the north of South America, which vary considerably in their richness in this alkaloid, and consequently in value ; the best samples of calisaya bark contain from 30 to 32 parts per 1,000 of the sulphate ; the poorer grades 4 to 20 parts per 1,000 ; inferior grades of bark contain from mere traces to 6 parts per 1,000. It is known in three different states of hydration, with 1, 2, and 3 Aq. and anhydrous. The anhydrous form is an amorphous, resinous sub- stance, obtained by evaporation of solutions in anhydrous alcohol or ether. The first hydrate is obtained in crystals by exposing to air recently pre- cipitated and well-washed quinine. The second by precipitating by am- monia a solution of quinine sulphate, in which H has been previously liberated by the action of Zn upon S04H2 ; it is a greenish, resinous body, which loses H,0 at 150° (302° F.). The third, that to which the following remarks apply, is formed by precipitating solution of quinine salts with ammonia. It crystallizes in hexagonal prisms ; very bitter; fuses at 57° (134°. 6 F.); loses Aq. at 100° (212° F.) and the remainder at 125° (257° F.); becomes colored, swells up, and, finally, burns with a smoky flame. It does not sublime. It dissolves in 2,200 pts. of cold H20, in *760 of hot II.,O ; very soluble in alcohol and chloroform ; soluble in amyl alcohol, benzene, fatty and essential oils, and ether. Its alcoholic solution is powerfully lsevogy- rous, [a]n = —270°.7 at 18° (64°.4 F.), which is diminished by increase of temperature, but increased by the presence of acids. Analytical Characters.—(1.) Dilute S04H2 dissolves quinine in color- less but fluorescent solution (see below). (2.) Solutions of quinine salts turn green when treated with Cl and then with NH3. (3.) Cl passed through H20 holding quinine in suspension forms a red solution. (4.) Solution of quinine treated with Cl water and then with fragments of potassium ferrocyanide becomes pink, passing to red. Sulphate —Disulphate—Quinince sulphas (US.)—Quinice sulphas (Br.)— lAq—746 + 126—crystallizes in prismatic needles; very light; intensely bitter; phosphorescent at 100° (212° F.); fuses readily ; loses its Aq. at 120° (248° F.), turns red, and finally carbonizes ; effloresces in air, losing 6 Aq.; soluble in 740 pts. H20 at 13° (55°.4F.), in 30 pts. boiling H20, and 60 pts. alcohol. Its solution with alcoholic solution of I deposits brilliant green crystals of iodoquinine sulphate. Hydrosulphate—Quinince bisulphas (U. S.)—S04H(C3tH2.N,,0.2) 4- 7Aq. —422 + 126—is formed when the sulphate is dissolved in excess of dilute It crystallizes in long, silky needles, or in short, rectangular prisms; soluble in 10 pts. H.,0 at 15° (59° F.). Its solutions exhibit a marked fluorescence, being colorless, but showing a fine pale blue color when illuminated by a bright light against a dark background. Impurities.—Quinine sulphate should respond to the following tests : (1.) When 1 gram (15.4 grains) is shaken in a test tube with 15 c.c. (4 fl 3 ) of ether, and 2 c.c. (32 Tfp.) of NH4HO ; the liquids should sep- arate into two clear layers, without any milky zone between them (cin- chonine). (2.) Dissolved in hot H„0, the solution precipitated with an alkaline oxalate, the filtrate should not ppt. with NH(HO (quinidine). (3.) It should dissolve completely in dilute S04H2 (fats, resins). 17 258 MANUAL OF CHEMISTRY. (4.) It should dissolve completely in boiling, dilute alcohol (gum, starch, salts). (5.) It should not blacken with SO H2 (cane-sugar). (6.) It should turn red or yellow with S04H2 (salicin and phlorizin). (7.) It should leave no residue when burnt on platinum foil (mineral substances). Cinchonine—Ginchonina (U. S.)—C19H22N20—294—occurs in Peru- vian bark in from 2 to 30 pts. per 1,000. It crystallizes without Aq. in colorless prisms ; fuses at 150° (302'3 F.) ; soluble in 3,810 pts. H20 at 10° (50° F.), in 2,500 pts. boiling H20 ; in 140 pts. alcohol and in 40 pts. chloroform. The salts of cinchonine resemble those of quinine in composi- tion ; are quite soluble in H20 and alcohol; are not fluorescent; perma- nent in air ; phosphorescent at 100° (212° F.). Quinidine and Quinicine—are bases isomeric with quinine ; the former occurring in cinchona bark, and distinguishable from quinine by its strong dextrorotary power; the second a product of the action of heat on quinine, not existing in cinchona. Cinchonidine—a base, isomeric with cinchonine, occurring in certain varieties of bark; lsevogyrous. At 130° (266° F.) S04H2 converts it into another isomere, cinchonicine. Caffeine—Theine—Guaranine—Gaffeina (U. S.)—C8H]0N4O2 + Aq— 194 + 18—exists in coffee, tea, Paraguay tea, and other plants. It crys- tallizes in long, silky needles ; faintly bitter ; soluble in 75 pts. H„0 at 15° (59° F.) ; less soluble in alcohol and ether. Hot fuming NOsH con- verts it into a yellow liquid, which after evaporation, turns purple with nh4ho. Alkaloids of the Loganiaceae. Strychnine—Strychnina (U. S.)—C1H,,„N'202—334—exists in the seeds and bark of different varieties of strychnos. It crystallizes on slow evaporation of its solutions in orthorhombic prisms, by rapid evaporation as a crystalline powder ; very sparingly solu- ble in H20 and in strong alcohol ; soluble in 5 pts. chloroform. Its aqueous solution is intensely bitter, the taste being perceptible in a solu- tion containing 1 pt. in 600,000. It is a powerful base ; neutralizes and dissolves in concentrated SO ,H2 without coloration ; and precipitates many metallic oxides from solutions of their salts. Its salts are mostly crystallizable, soluble in H,,0 and alco- hol, and intensely bitter. The acetate is the most soluble. The neutral sulphate crystallizes, with 7 Aq., in rectangular prisms. The iodides of methyl and ethyl react with strychnine to produce the iodides of methyl or ethylstrychnium, white crystalline basic substances, producing an ac- tion on the economy similar to that of curare. When acted on by S04Ha and potassium chlorate, with proper precautions, strychnic or igasuric acid is formed. Analytical Chabacters.—(1.) Dissolves in concentrated S04H2 without color. The solution deposits strychnine when diluted with H20, or when neutralized with magnesia or an alkali. (2.) If a fragment of potassium dichromate (or other substance capable of yielding nascent O) is drawn through a solution of strychnine in S04H2 it is followed by a streak of color ; at first blue (very transitory and fre- quently not observed), then a brilliant violet, which slowly passes to rose- pink and finally to yellow. Reacts with jo-J-ot grain of strychnine. ALKALOIDS OP THE SOLAHACEiE. 259 (3.) A dilute solution of potassium dichromate forms a yellow, crystal- line ppt. in strychnine solutions ; which, when washed and heated with concentrated S04H„ gives the play of colors indicated in 2. (4.) If a solution of strychnine be evaporated on a bit of platinum foil, the residue moistened with concentrated S04H2, the foil connected with the + pole of a single Grove cell, and a platinum wire from the — pole brought in contact with the surface of the acid, a violet color appears upon the surface of the foil. (5.) Strychnine and its salts are intensely bitter. (6.) A solution of strychnine introduced under the skin of the back of a frog causes difficulty of respiration and tetanic spasms, which are aggra- vated by the slightest irritation, and twitching of the muscles during the intervals between the convulsions. With a small frog, whose surface has been dried before injection of the solution, grain of acetate of strychnine will produce tetanic spasms in 10 minutes and death in 2 hours. (7.) Solid strychnine, moistened with a solution of iodic acid in S04H2, produces a yellow color, changing to brick-red and then to violet-red. (8.) Moderately concentrated N03H colors strychnine yellow in the cold. A pink or red color indicates the presence of brucine. Toxicology.—Strychnine is one of the most active and most frequently used of poisons. It produces a sense of suffocation, thirst, tetanic spasms, usually opisthotonos, sometimes emprosthotonos, occasionally vomiting, contraction of the pupils during the spasms, and death, either by asphyxia during a paroxysm or by exhaustion during a remission. The symptoms appear in from a few minutes to an hour after taking the poison, usually in about 20 minutes ; and death in frpm 5 minutes to 6 hours, usually within 2 hours. Death has been caused by grain, and recovery has fol- lowed the taking of 20 grains. The treatment should consist of the removal of the unabsorbed poison by the stomach-pump, injecting charcoal, and pumping it out after about 5 minutes ; under the influence of chloroform if necessary. Chloral hydrate should be given. Strychnine is one of the most stable of the alkaloids, and may remain for a long time in contact with putrefying organic matter without suffering decomposition. Brucine C23H2rN204 -t- 4 Aq —394 + 72—accompanies strychnine. It forms oblique rhomboidal prisms, which lose their Aq. in dry air. Sparingly soluble in H20; readily soluble in alcohol, chloroform, and amyl alcohol ; intensely bitter. It is a powerful base and most of its salts are soluble and crystalline. Its action on the economy is similar to that of strychnine but much less energetic. Analytical Characters. — (1.) Concentrated N03H colors it bright red, soon passing to yellow ; stannous chloride, or colorless NH4HS, change the red color to violet. (2.) Chlorine water, or Cl, color brucine bright red, changed to yellow- ish brown by NH4HO. Alkaloids of the Solanaceae. Solanine—C43H71NOi(.—857—obtained from many species of Solarium; crystallizes in small, white, bitter, sparingly soluble prisms. Concen- trated S04H2 colors it orange red, passing to violet and then to brown. It is colored yellow by concentrated HC1. It dissolves in concentrated 260 MANUAL OF CHEMISTRY. N03H, the solution being at first colorless, but after a time becomes purple. Atropine—Daturine—Atropina (U S.)—C17H23N03—289—the active principle of belladonna, crystallizes in colorless, bitter, alkaline, sparingly soluble needles. It volatilizes when solutions of its salts are boiled. It has been obtained by partial synthesis. Toxicology.—It is actively poisonous, producing drowsiness, dryness of the mouth and throat, dilatation of the pupils, loss of speech, diplopia, dizziness, delirium, coma. The treatment should consist in the administration of emetics and the use of the stomach-pump. Analytical Characters. -(1.) If a fragment of potassium dichromate be dissolved in a few drops of S04H2, the mixture warmed, a fragment of atropine and a drop or two of H20 added and the mixture stirred, an odor of orange blossoms is developed. (2.) A solution of atropine dropped upon the eye of a cat produces dilatation of the pupil. Hyoscyamine—C16H23N03—265—the active principle of hyoscyamus niger, forms a yellow, hygroscopic mass; has the odor of tobacco and a sharp, disagreeable taste. Alkaloids from other Sources. Colchicine—from colchicum autumnale ; is colored yellow, then green by S04H2; and violet, then green by N03H. Veratrine—from veratrum album and viride ; is colored yellow, red, and purple by S04H2. Bromine water colors it violet, then violet red ; and boiling HC1 colors it red. Physostigmine—Eserine—from physostigma venenosum; is colored by S04H3 yellow passing to red, or to reddish-brown on addition of bromine water. Aconitine—from aconitum napellus; is colored yellow by S04H2, changing to brown, red-brown and violet. Ptomaines—Septicine.—Under these names substances have been described which are produced from animal tissues in complete or in- cipient putrefaction, and even from the living body under certain patho- logical conditions. Some are fixed, others volatile ; some soluble in ether, others insoluble in ether but soluble in amyl alcohol, and others insoluble in both liquids. Some are strong reducing agents and respond to the iodic acid test for morphine. They are readily oxidizable, turn brown on contact with air, and give off odors resembling those of urine, of coniine or of certain flavors. They are pungent in taste, and produce a sense of numbness in the tongue, and a tickling sensation in the throat. Some are non-poisonous, others are actively toxic. They react with the general tests for the alkaloids. ALBUMINOIDS AND GELATINOIDS. Protein Bodies. The substances of this class are never absent in living vegetable or ani- mal cells, to whose “ life ” they are indispensable. They are as yet the products exclusively of the organized world. ALBUMINOIDS AND GELATINOIDS. 261 Physical Characters.—They are almost all uncrystallizable and incap- able of dialysis. Some are soluble in water, others only in water contain- ing traces of other substances, others are insoluble. Their solutions are all ltevogyrous. Some are separated as solids from their solutions, in a permanently modified form, by heat and by certain reagents ; a change called coagulation. When once coagulated they cannot be redissolved. The temperature at which coagulation by heat occurs varies with dif- ferent albuminoids, and is of value in distinguishing them from one an- other. Composition.—They consist of C, N, H, O, and usually a small quantity of S, and form highly complex molecules whose exact composition is un- certain. Of their constitution nothing is definitely known, although there is probability that they are highly complex amides, related to the ureids, and formed by the combination of glycollamine, leucine, tyrosine, etc., with radicals of the acetic and benzoic series. General Reactions.—They all respond to the following tests: (1.) A purple red color when warmed to 70° (158° F.) withMillon’s re- agent. The reagent is made by dissolving, by the aid of heat, 1 pt. Hg in 2 pts. N03H of sp. gr. 1.42 ; diluting with 2 vols. H,0, and decanting after 24 hours. (2.) A yellow color with N03H ; changing to orange with NH4HO (Xanthoproteic reaction). (3.) A purple color with Pettenkofer’s test (q. v.). (4.) With a drop or two of cupric sulphate solution and liquor potassse a violet color. (5.) A solution of an albuminoid in excess of glacial acetic acid is colored violet and rendered faintly fluorescent by concentrated S04H,. (6.) With potassium ferrocyanide, in solutions strongly acid with acetic acid, a white ppt. Decompositions.—Dilute acids decompose them into two substances : one insoluble, amorphous, yellowish, called hemxprotein ; the other soluble in water, insoluble in alcohol, faintly acid, called hemialbumin. A pro- longed boiling with moderately concentrated SO,H, decomposes them, forming well-defined substances—glycocol, leucine, tyrosine ; aspartic and glutamic acids. Alkalies dissolve them more or less readily ; on boiling the solution, part of the sulphur is converted into sulphide and hyposul- phite. Their alkaline solutions, when neutralized by acids, deposit Mul- der’s proteine. Concentrated alkalies decompose them into amido-acids. By fusion with alkalies, alkaline cyanides are also produced. When they are heated with caustic baryta and water at 100° (212° F.) carbonate, sul- phate, oxalate, and phosphate of barium are deposited, and C02 and NHS are given off in the same proportions as when urea is similai'ly treated ; when the temperature is raised, under pressure, finally to 200° (392° F.), a crystalline mass is formed which contains oxalic and acetic acids, a num- ber of amido-acids, aspartic and glutamic acids, and a substance x'esemb- ling dextrin. Heated with HnO, under pressure, they are partly dissolved and partly decomposed. A mixture of S04H, and manganese dioxide, or potassium dichromate, produces from the albuminoids, aldehydes, and acids of the fatty and benzoic series, hydrocyanic acid, and cyanides. When heated under pressure with Br and H„0 they yield CO,, oxalic and aspartic acids, amido acids, and bromine derivatives of the fatty and ben- zoic series. Potassium permanganate produces from them urea, C02, KH3 and H,0. Putrefaction—is a decomposition of dead albuminoid and gelatinous mat- 262 MANUAL OF CHEMISTRY. ter, attended by the evolution of fetid gas, and by the appearance of low forms of organized beings (bacteria). That it may occur there must have been contact with air, and there must be presence of moisture and a temperature between 5°-90° (41°-194° F.). It is attended by the breaking down and liquefaction of the material if it be solid ; or its clouding and the formation of a scum upon the sur- face if it be liquid. The products of putrefaction vary with the conditions under which it occurs, the most prominent are : N, H, hydrocarbons, H„S, NH.„ CO,„ certain ill-defined phosphorized and sulphurated bodies, acids of the acetic and lactic series, amido acids, and alkaloidal substances. Under certain imperfectly defined conditions, buried animal matter is converted into a substance resembling tallow, and called adipocere, which consists chiefly of palmitate, stearate, and oleate of ammonium, phosphate and carbonate of calcium, and an undetermined nitrogenous substance. Putrefaction may be prevented by: (1) exclusion of air ; (2) removal of water ; (3) maintaining the temperature below 5° (41° F.); (4) the action of antiseptics. Antiseptics are substances which prevent or restrain putrefaction. Deodorizers, or air purifiers, are substances which destroy the odorous pro- ducts of putrefaction. Disinfectants are substances which restrain infectious diseases by destroying their specific poisons. Certain substances are antiseptic, deodorant, and disinfectant; such are : chlorine, bromine, iodine, the hypochlorites, and sulphur dioxide ; others lack one of the powers, as the mineral acids and the non-volatile “ disinfectants,” which are antiseptic and disinfectant, but not deodorant. Still others exert but one of the powers, as water and air, which may be mechanical deodorants, but neither disinfectants nor antiseptics. There occurs a decomposition of vegetable tissues under the influence of warmth and moisture, which is known as eremacausis, differing from putrefaction in that the substances decomposed are the carbohydrate in- stead of the azotized constituents, and in the products of the decomposi- tion, there being no fetid gases evolved (except there be simultaneous putrefaction), and the final product is a brownish material (humus or ulmin). Classification.—In the present unsatisfactory state of our knowledge of the chemical constitution of these substances, we can only adopt a tempo- rary classification, based upon their physical and physiological characters. A. Albuminoids : I. Soluble in pure water; coagulated by heat.—The true albumins of the white of egg, serum, and vegetable albumin. II. Insoluble in pure water; soluble in water without alteration in presence of neutral salts, alkalies and acids; and capable of precipitation unchanged from these solutions. 1. Globulins.—Yitellin, myosin, paraglobulin, fibrinogen. 2. Animal caseins.—Milk casein, serum casein. 3. Vegetable caseins.—Gluten casein, legumin, conglutin. 4. First terms of decomposition of the albuminoids by acids, alkalies, and crxjptolytes.—Albuminates (so called), acid albumin, syntonin, liemiprotein, peptone. III. Insoluble in water and only soluble after decomposition. Cannot be separated without alteration from their solutions in acids and alkalies.—Gluten fibrin, gliadin, mucedin. IY. Coagulated.—Coagulated albumin and fibrin. Y. Amyloid matter.—Lardacein. ALBUMINOIDS AND GELATINOIDS. 263 B. Gelatinoids : I. Collagenes.—Collagen, elastin, ossein and its derivatives, chondrigen ? cliondrin ? gelatin, keratin. II. Mucilaginous bodies.—Mucin, paralbumin, colloidin. Albuminoids. I.—Egg albumin exists in solution, imprisoned in a network of deli- cate membranes, in the white of egg. It is obtained in an impure condi- tion by cutting the whites of eggs with scissors, expressing through linen, diluting with an equal volume of water, filtering and concentrating the filtrate at a temperature below 40° (104° F.); mineral salts, which adhere to it tenaciously, are separated by dialysis. It seems to be a mixture of two different substances, one of which coagulates at 63° (145°.4 F.), and has the rotary power [a]D=— 43° ; the other coagulates at 74° (165°.2 F.), and has the value of [a]D = — 26°. Its solutions are not precipitated by a small quantity of HC1, but an excess of that acid produces a deposit which is difficultly soluble in HC1, H O, and salt solution. Its characteristic reaction is that it is coagulated by agitation with ether. Serum-albumin exists in blood-serum, chyle, lymph, pericardial fluid, the fluids of cysts and of transudations, in milk and, pathologically, in the urine. It is best obtained from blood-serum, after removal of para- globulin (q. u.), by a tedious process, and only then in a state of doubtful purity. It is less abundant in the blood of some animals than paraglobu- lin, but more abundant in that of man. Solutions of serum-albumin are kevogvrous [a]„ =— 56° ; they are not precipitated by CO„, by acetic or orthophosphoric acid, by ether or by magnesium sulphate. They are precipitated by mineral acids, tannic acid, metaphosphoric acid, and most metallic salts. When heated they become opalescent at 60° (140° F.), and coagulate in the flocculent form at 72°- 75° (161°.6-167° F.). Detection and Determination of Albumin in Urine.—If the urine be not perfectly clear it is filtered, if this do not render it perfectly transparent, it is treated with a few drops of magnesia mixture (p. 85 note), and again filtered. The filtrate, if alkaline, is rendered just acid by adding acetic acid guttatim (nitric acid should not be used, and the acidu- lation of alkaline urine is imperative). The urine is now heated to near boiling, and if a cloudiness or precipitate be formed, no3h is added slowly to the extent of about 10 drops. If heat produce a cloudi- ness, which clears up completely on addi- tion of N03H, it is due to an excess of earthy phosphates. If a cloudiness pro- duced by heat do not clear up (it may in- crease) on addition of N03H it is due to albumin. Small quantities of albumin may some- times be better detected by Heller’s test: A layer of N03H is placed in a test-tube, which is then held at an angle and the urine allowed to flow slowly upon its surface (Fig. 40) so as to form a distinct layer, with the Fig. 40. MANUAL OF CHEMISTRY. minimum of mixing of tlie two liquids; tlie test-tube is then brought to the vertical slowly, and the point of junction of the two liquids examined against a dark background. If albumin be present a white, opaque band, whose upper and lower borders are sharply defined, will be seen at the line of junction of the two liquids. When urates are present in excess, a white band will be observed, but its position will be rather above the line of junction, and its upper border will not be sharply defined, but gradually diminish in density from below upward. In non-albuminous urines there is usually a darkening, but never an opacity at the line of junction. Quantity.—The only method of determining the quantity of albumin in urine, with an approach to accuracy, is gravimetric : 20-50 c.c. (5.4-13.5 fl 3 ) of the filtered urine (according as the qualitative testing shows albumin to be present in large or small quantity) are slowly heated over the water-bath, and, as the boiling temperature is approached, 3-4 drops of acetic acid are added. After the urine has boiled for a few moments, it is thrown upon a filter. The coagulum is washed with boiling HaO, then with H20 acidulated with N03H, then with alcohol and finally with ether. By these washings impurities are removed, and the albumin is caused to contract firmly, so that it can be easily detached and transferred to a weighed watch- glass : upon this it is dried at 115° (239° F.) and the whole weighed. The difference between the last weight and that of the watch-glass, is the weight of dry albumin in the volume of urine used. Vegetable albumin—exists in solution in all vegetable juices, and forms the most valuable constituent of those vegetables which are used as food. It is coagulated from its solutions at Gl°-63° (141°.8-145°.4 F.), and by nearly all acids. II.—Vitelin exists in the yolk of egg and in the crystalline lens. It is soluble in dilute solution of sodium chloride, from which it is precipi- tated by excess of H20 ; by heating to 75°-80° (167°-176° F.); and by alcohol. It is not precipitated by solid sodium chloride. It dissolves in weak alkaline solutions without alteration and in very dilute HC1 (1-1000), by which it is quickly converted into syntonin. Myosin—is one of the principal constituents of the muscular fibre in rigor mortis. It is a faintly yellow, opalescent, distinctly alkaline liquid, which, when dropped into distilled H20, deposits the myosin in globular masses, while the H.,0 assumes an acid reaction. It is insoluble in H.,0, easily soluble in dilute salt solution, from which it is precipitated by the addition of solid sodium chloride, or by a heat of 55°-60° (131°-140° F.). Very dilute HC1 dissolves and converts it into syntonin. Paraglobulin.—This substance has been described by various authors under the names: plasmine (Denis), serum casein (Panumi, serum glob- uline, fibrino-plastic matter (Schmidt), serin (Denis). It exists in blood- serum, in pericardial fluid, hydrocele fluid, lymph and chyle, from which it is obtained by diluting with 10-15 volumes of ice-cold H„0, treatment of the solution with strong current of C02, and washing the collected deposit with H,0 as long as a portion of the filtrate precipitates with acetic acid and potassium ferrocyanide, or with silver nitrate. It is a granular substance, which gradually becomes more compact; insoluble in H20, sparingly soluble in H.,0 containing CO,,; soluble in dilute alkalies, in lime-water, in solutions of neutral alkaline salts, in dilute acids. Its solution in very dilute alkaline fluids is perfectly neutral and is not coagulated by heat, except after faint acidulation with acetic or mineral acids; it is precipitated by a large volume of alcohol ; its solutions are also precipitated incompletely by dissolving sodium chloride in them to saturation, and completely by similar solution of magnesium sulphate ; this last method of precipitation is used for the separation of paraglobulin from serum-albumin (see Fibrin). Fibrinogen—after the separation of paraglobulin from blood-plasma, as described above, if the liquid be still further diluted and again treated with C02, a substance is obtained which, although closely resembling ALBUMINOIDS AND GELATINOIDS. 265 paraglobulin in many characters, is distinct from it, and, unlike paraglob- ulin, it cannot be obtained from the serum separated from coagulated blood. Paraglobulin and fibrinogen are both soluble in a solution of sodium chloride containing 5-8 per cent, of the salt ; when the degree of concen- tration of the salt solution is raised to 12-16 per cent., the fibrinogen is precipitated, while the paraglobulin remains in solution and is only pre- cipitated, and then incompletely, when the percentage of salt surpasses twenty (see Fibrin). Mils casein—the most abundant of the albuminoids of the milk of mammalia, closely resembles alkali albuminates, with which it is probably identical, as the main point of distinction has been found to be without significance. Unlike pure alkali albuminates, casein is coagulated from its solution by rennet (the product of the fourth stomach of the calf) at 40° (104° F.); but it has been found that alkali albuminate is also so coagu- lated when milk-sugar and fat are added to the solution. Milk. —The secretion of the mammary gland is water holding in solu- tion casein, albumin, lactose, and salts ; and fat in suspension. Cream consists of the greater part of the fat, with a small proportion of the other constituents of the milk. Skim milk is milk from which the cream has been removed. Buttermilk is cream from which the greater part of the fat has been removed, and consequently is of about the same composition as skim milk. The composition of milk differs in animals of different species : Human. Cow. Goat. Sheep. Ass. Mare. Cream. Condens- ed milk. Water.... 88.35 84.28 86.85 83.30 89.01 90.45 45.99 25.68 Solids.... 11.65 15.72 13.52 16.60 10.99 9.55 54.01 74.32 Casein ... Albumin.. | 3.15 { 3.57 0.78 2.53 1.26 } 5.73 3.57 2.53 6.33 16.83 Fat 3.87 6.47 4.34 6.05 1.85 1.31 43.97 10.27 Lactose .. Salts 4.37 0.26 4.34 0.63 3.78 0.65 3.96 0.68 l 5.05 j 5.43 { 0.29 3.28 0.42 44.33* 2.80 * Including 28.98 parts of cane-sugar. The composition of cows’ milk varies considerably according to the age, condition, breed and food of the cow ; to the time and frequency of milking ; and to whether the sample examined is from the first, middle, or last part of each milking. Cows’ milk is very frequently adulterated, both by the removal of the cream and the addition of water. For ordinary purposes, the purity of the milk may be determined by observing the sp. gr. and the percentage of cream by the lactometer and creamometer, neither of which, used alone, affords indications which can he relied upon. The sp. gr. should be ob- served at the temperature for which the instrument is made, as in a com- plex fluid such as milk no valid correction for temperature is practical; it ranges in pure milk from 1027 to 1034, it being generally the lower in milk which has been watered, and in such as is very rich in cream, and the higher the less cream is present. The average sp. gr. is 1030 ; the average percentage of cream 13. The percentage of cream is determined by the creamometer: a glass 266 MANUAL OF CHEMISTRY. tube about a foot long and half an inch in diameter, the upper fifth (ex- cluding about an inch from the top) being graduated into hundredths of the whole, the 0 being at the top. To use it, it is simply filled to the 0 with the millc to be tested, set aside for twenty hours and the point of sep- aration between milk and cream read off. It should be above eight per cent. This method of determining the purity of milk, although sufficient for ordinary purposes, should not be considered as affording evidence upon which to base legal proceedings ; in such cases nothing short of a chemical determination of the percentage of fats, and of solids not fat, should be accepted as evidence of the impurity of milk. Serum-cassin is a substance obtained from blood-serum diluted with 10 volumes of H20, freed from paraglobulin by CO,,, and from albumin by acetic acid and heat. It is insoluble in salt solutions, slowly soluble in a one per cent, solution of sodium hydrate. Such a solution is partially pre- cipitated by C02, almost completely by acetic acid, and completely by heat- ing with excess of powdered sodium chloride ; incompletely soluble in di- lute HC1. Gluten-casein.—That portion of crude gluten (a soft, elastic, grayish, material best obtained from flour) which is insoluble in alcohol, hot or cold ; Legumin—a sparingly soluble albuminoid obtained from peas, beans, etc.; and Conglutin—a substance closely related to legumin and to gliadin, but differing from them in some characters, obtained from almonds, are three vegetable albuminoids resembling casein. They are insoluble in pure water, readily soluble in dilute alkaline so- lutions, from which they are precipitated by acids and by rennet. Alkali albuminates—proteins of Hoppe Seyler—are formed when an albuminoid is dissolved in concentrated solutions of potassium and sodium hydrates ; it is very probable that they are identical with serum and milk- casein. Acid albumins—are substances obtained by precipitating solutions of albuminoids by the simultaneous addition of an acid and a large quan- tity of a neutral salt; they vary exceedingly in composition and proper- ties. Syntonin—Parapeptone—is extracted from contractile tissues. The same substance is formed by the action of dilute acids upon the albumi- noids, and as the first product of the action of the gastric juice, or of mix- tures of pepsin and dilute acid upon albuminoids. It resembles serum casein closely, the only divergence in their properties being that syntonin is much more readily soluble in a 0.1 per cent, solution of HC1, and in faintly alkaline liquids. Peptone—Albuminose—is the product of the action of the gastric and pancreatic juices upon albuminoids during the process of digestion. It is soluble in H20, insoluble in alcohol and in ether. Its watery solution is neutral, not precipitable by acids or alkalies, or by heat w hen faintly acid. Alcohol precipitates it in white, casein-like flocks, which, if slowly heated to 90° (194° F.) while still moist form a transparent, yellowish liquid, and, on cooling, an opaque, yellowish, glassy mass. It has a greater power than other albuminoids of combining with acids and bases. The most important character of peptone, in which it differs from other albuminoids, is that it is readily dialysable. Its presence in the blood has not been demonstrated, and it is probable that immediately upon its en- trance into the circulation it is converted into albuminoids resembling, yet differing from, those from which it was derived. ALBUMINOIDS AND GELATINOIDS. 267 IV. —Coagulated albumins—are obtained, as described above, from the soluble varieties by the action of acids, heat, alcohol, etc. They are insoluble in water, alcohol, solutions of neutral salts ; difficultly soluble in dilute alkaline solutions. In acetic acid they swell up and dissolve slowly; from this solution they are precipitated by concentrated salt solution. Concentrated HC1 dissolves them with formation of syntonin. By the ac- tion of gastric juice, natural or artificial, they are converted first into syn- tonin, then into peptone. Fibrin—is obtained when blood is allowed to coagulate or is whipped with a bundle of twigs. When pure it is at first a gelatinous mass, which contracts to a white, stringy, tenacious material, made up of numerous minute fibrils ; when dried it is hard, brittle, and hygroscopic. It is in- soluble in water, alcohol, ether ; in dilute acid it swells up and dissolves slowly and incompletely. When heated with water to 72° (161°.6 F.), or by contact with alcohol, it is contracted, and is no longer soluble in dilute acids, but soluble in dilute alkalies. In solutions of many neutral salts of 6-10 per cent., it swells up and is partially dissolved ; from this solu- tion it separates on the addition of water, or upon the application of heat to 73° (163°. 4 F.), or by acetic acid or alcohol. Moist fibrin has the property of decomposing oxygenated water with copious evolution of oxygen. Fibrin does not exist as such in the blood, and the method of its form- ation and of the clotting of blood has been the subject of much experiment and argument; nor can the question be said to be definitely set at rest. In the light of the researches of Denis, Schmidt, and especially of Hammar- sten, it may be considered as almost proven that fibrin is formed from fibrinogen under favorable circumstances, and by a transformation which is not yet understood. Whether paraglobulin plays any part directly in the formation of fibrin or not, is still an open question. V. —Amyloid—is a pathological product, occurring in fine grains, re- sembling starch-granules in appearance, in the membranes of the brain and cord, in waxy and lardaceous liver, and in the walls of the blood-ves- sels. Its composition is that of the albuminoids, from which it differs in being colored red by iodine ; violet or blue by iodine and S04H2. Soluble in HC1 with formation of syntonin ; and in alkalies. It is not at- tacked by the gastric juice, and is not as prone to putrefaction as the other albuminoids. Gelatinoids. I.—Collagen.—Bony tissue is made up mainly of tricalcic phosphate, combined with an organic material called ossein, which is a mixture of collagen, elastin, and an albuminoid existing in the bone-cells. Collagen also exists in all substances which, when treated with HO, under the in- fluence of heat and pressure, yield gelatin. It is insoluble in cold H20, but by prolonged boiling is converted into gelatin, which dissolves. It is dissolved by alkalies. Gelatin—obtained as above, from ossein, exists in the commercial pro- duct of that name, and in a less pure form in glue. When pure it is an amorphous, translucent, yellowish, tasteless substance, which swells up in cold H.O, without dissolving, and forms, with boiling H„0, a thick, sticky solution, which on cooling becomes, according to its concentration, a hard glassy mass or a soft jelly—the latter even when the solution is very dilute. It is insoluble in alcohol and ether, but soluble, on warming, in glycerin ; 268 MANUAL OF CHEMISTRY. the solution in the last-named liquid forms, on cooling, & jelly which has recently been applied to various contrivances for copying writing. A film of gelatin impregnated with potassium dichromate becomes hard and insol- uble on exposure to sunlight. Ghondrin is the name given to a substance obtained from cartilaginous tissue and supposed to be distinct from gelatin. It is probably a mixture of gelatin and mucin. Elastin—is obtained from elastic tissues by successive treatment with boiling alcohol, ether, water, concentrated acetic acid, dilute potash solu- tion and water. It is fibrous, yellowish ; swells up in water and becomes elastic; soluble with a brown color in concentrated potash solution. It contains no S, and on boiling with S04H2 yields glycol. Keratin—is the organic basis of horny tissues, hair, nails, feathers, whalebone, epithelium, tortoise-shell, etc. It is probably not a distinct chemical compound, but a mixture of several closely related bodies. II.—Mucin—is a substance containing no S and existing in the differ- ent varieties of mucus, in certain pathological fluids, in the bodies of mol- luscs, in the saliva, bile, connective tissues, etc. Its solutions, like the fluids in which it occurs, are viscid. It is precipitated by acetic acid and by NOsH, but is dissolved by an excess of the latter; it dissolves readily in alkaline solutions, and swells up in H20, with which it forms a false solution. It is not coagulated by heat. ANIMAL CRYPTOLYTES. Soluble Animal Ferments. Under this head are classed substances somewhat resembling the al- buminoids, of unknown composition, occurring in animal fluids, and having the power of effecting changes in other organic substances, the method of whose action is undetermined. (See p. 120.) Ptyalin—is a substance occurring in saliva, and having the power of converting starch into dextrin and a sugar resembling glucose (ptyalose), in liquids having an alkaline, neutral, or faintly acid reaction. Pepsin—is the cryptolyte of the gastric juice. Attempts to separate it without admixture of other substances have hitherto proved fruitless ; nevertheless, mixtures containing it and exhibiting its characteristic prop- erties more or less actively have been obtained by various methods. The most simple consists in macerating the finely divided mucous membrane of the stomach in alcohol for 48 hours, and afterward extracting it with gly- cerin ; this forms a solution of pepsin, which is quite active and resists putrefaction well, and from which a substance containing the pepsin is precipitated by a mixture of alcohol and ether. If pepsin be required in the solid form, it is best obtained by Briicke’s method. The mucous membrane of the stomach of the pig is cleaned and detached from the muscular coat by scraping ; the pulp so obtained is di- gested with dilute phosphoric acid at 38° (100°.4 F.), until the greater part of it is dissolved ; the filtered solution is neutralized with lime-water ; the precipitate is collected, washed with H20, and dissolved in dilute HC1; to this solution a saturated solution of cliolesterin, in a mixture of 4 pts. alcohol and 1 pt. ethei’, is gradually added; the deposit so formed is repeatedly shaken with the liquid, collected on a filter, washed with H ,0 and then with dilute acetic acid, until all HC1 is removed ; it is then ANIMAL COLORING MATTERS. 269 treated with ether and H20 : the former dissolves cholesterin and is poured off, the latter the pepsin ; after several shakings with ether the aqueous liquor is evaporated at 38° (100°.4 F.;, when it leaves the pepsin as an amorphous, grayish-white substance ; almost insoluble in pure H.,0, readily soluble in acidulated HaO ; probably forming a compound with the acid, which possesses the property of converting albuminoids into peptone. The so-called pepsina porci is either the calcium precipitate obtained as described in the first part of the above method: or, more commonly, the mucous membrane of the stomach of the pig, scraped off, dried, and mixed with rice-starch or milk sugar. Pancreatin.—Under this name, substances obtained from the pancre- atic secretion, and from extracts of the organ itself, have been described, and to some extent used therapeutically. They do not, however, contain all the cryptolytes of the pancreatic juice, and in many instances are inert albuminoids. The actions of the pancreatic juice are : (1) it rapidly con- verts starch, raw or hydrated, into sugar; (2) in alkaline solution—its natural reaction—it converts albuminoids into peptone ; (3) it emulsifies neutral fats; (4) it decomposes fats, with absorption of H,0 and libera- tion of glycerin and fatty acids. The pancreatic secretion probably contains a number of cryptolytes— certainly two. The one of these to which it owes its peptone-forming power has been obtained in a condition of comparative purity by Kiihne, and called by him trypsin ; in aqueous solution it digests fibrin almost immediately, but it exerts no action upon starch. The diastatic (sugar-forming) cryptolyte of the pancreatic juice has not been separated, although a glycerin extract of the finely divided pancre- atic tissue contains it, along with trypsin. ANIMAL COLORING MATTERS. Haemoglobin and its Derivatives—Hcemato-crystallin.—The color- ing matter of the blood is a highly complex substance, resembling the albuminoids in many of its properties, but differing from them in being crystallizable and in containing iron. Haemoglobin exists in the red-blood corpuscles in two conditions of oxidation ; in the form in which it exists in arterial blood it is loosely com- bined with a certain quantity of oxygen, and is known as oxyhcemoglobin. The mean of many nearly concording analyses shows its composition to be CB(l0H9(i0Nj64FeS3O179. When obtained from the blood of man and from that of many of the lower animals, it crystallizes in beautiful red prisms or rhombic plates ; that from the blood of the squirrel in hexagonal plates ; and that from the guinea-pig in tetrahedra. The crystals are always doubly refracting. It may be dried in vacuo at 0° (32° F.); if thoroughly dried below 0° (32° F.), it may be heated to 100° (212° F.) without decomposition, but the presence of a trace of moisture causes its decomposition at a much lower temperature. Its solubility in water varies with the species of animal from whose blood it was obtained ; thus, that from the guinea-pig is but sparingly soluble, while that from the pig is very soluble. It is also dissolved unchanged by very weak alkaline solutions, but is decomposed by acids or salts having an acid reaction. Haemoglobin, or reduced haemoglobin, is formed from oxyhemoglobin in 270 MANUAL OF CHEMISTRY. the economy during the passage of arterial into venous blood; and by the action of reducing agents, or by boiling its solution at 40° (104° F.) in the vacuum of the mercury pump. Oxyhsemoglobin is of a much brighter color than the reduced, and has a different absorption spectrum. The spectrum of oxyhaemoglobin varies with the concentration. In concentrated solutions the light is entirely absorbed, in more dilute solutions the spectrum 10, Fig. 14, is observed, and in still further dilutions 11, Fig. 14 ; in which the band at D is nar- rower, darker, and more sharply defined than the other. In highly diluted solution the band at D is alone visible. The spectrum of haemoglobin consists of a single band much broader and fainter than either of the oxy- haemoglobin bands (12, Fig. 14). Haunoglobin, in contact with O or air, is immediately converted into oxyhaemoglobin. With CO it forms a compound resembling oxylia moglo- bin in the color of its solution, but in which the CO cannot be replaced by O ; for which reason haemoglobin, once combined with CO, becomes per- manently unfit to fulfil its function in respiration (see p. 170). When a solution of oxyhaemoglobin is boiled, it becomes turbid, and a dirty, brownish-red coagulum is deposited ; the haemoglobin has been decomposed into an albuminoid (or mixture of albuminoids), called by Preyer globln, and hcematin. The latter, at one time supposed to be the blood-coloring matter, is a blue-black substance, having a metallic lustre and incapable of crystallization ; it is insoluble in water, alcohol, ether, and dilute acids; soluble in alkaline solutions. It has the composition CC(H70 Nf,Fe2O10. Its alkaline solutions exhibit the spectrum 13, Fig. 14. Although itself uncrystallizable, haematin combines with HC1 to form a compound which crystallizes in rhombic prisms, and which is identical with the earliest known crystalline blood pigment, hcemin, or Teiclmiann’s crystals. When reduced haemoglobin is decomposed as above, in the absence of oxygen, hrematin is not produced, but a substance identical with that called reduced hcematin, and called by Hoppe-Seyler hcemocromogen ; "whose spectrum is shown in 14, Fig. 14. If a solution of haemoglobin be exposed for some time to air it changes in color from red to brownish, and assumes an acid reaction ; it then ex- hibits the spectrum 15, Fig. 14, due to the production of methcemoglobin, probably a stage in the conversion of haemoglobin into liaematin and globin. Biliary pigments.—There are certainly four, and probably more, pigmentary bodies obtainable from the bile and from biliary calculi, some of which consist in great part of them. Bilirubin—C3„H36N406—is, when amorphous, an orange-yellow powder, and when crystalline, in red rhombic prisms. It is sparingly soluble in H20, alcohol, and ether ; readily soluble in hot chloroform, carbon disul- phide, benzene, and in alkaline solutions. When treated with N03H con- taining nitrous acid, or with a mixture of concentrated N03H and S04H2, it turns first green, then blue, then violet, then red, and finally yellow. This reaction, known as Gmelin’s, is very delicate, and is used for the de- tection of bile-pigments in icteric urine and in other fluids. Biliverdin—C32H3(.N408—is a green powder, insoluble in H20, ether, and chloroform ; soluble in alcohol and in alkaline solutions. It exists in green biles, but its presence in yellow biles or biliary calculi is doubtful. It responds to Gmelin’s test. In alkaline solution it is changed after a time into biliprasin. Bilifuscin—CirH2nN„04—obtained in small quantity from human gall- stones, is an almost black substance, sparingly soluble in H20, ether, and 271 ANIMAL COLORING MATTERS. chloroform ; readily soluble in alcohol and in dilute alkaline solutions. Its existence in the bile is doubtful. Biliprasin—C16HaaNsO0(?)—exists in human gall-stones, in ox-gall, and in icteric urine. It is a black, shining substance, insoluble in H O, ether, and chloroform ; soluble in alcohol and in alkaline solutions. Urobilin — Hyclrobilirubin — CsaH40N4O7.—Under the name urobilin, Jaffe described a substance which he obtained from dark, febrile urine, and which he regarded as the normal coloring matter of that fluid ; subse- quently he obtained it from dog’s bile and from human bile, from gall- stones and from faeces. Stercobilin, from the faeces, is identical with urobilin. Urinary pigments.—Our knowledge of the nature of the substances to which the normal urinary secretion owes its color is exceedingly unsatis- factory. Jaffe in his discovery of urobilin shed but a transient light upon the question, as that substance exists in but a small percentage of normal urines, although they certainly contain a substance readily convertible into it. Besides the substance convertible into urobilin, and sometimes urobilin itself, human and mammalian urines contain at least one other pigmentary body, uroxanthin, or indigogen. This substance was formerly considered as identical with indican, a glucoside existing in plants of the genus Isatis, which, when decomposed, yields, among other substances, indigo-blue. Uroxanthin, however, differs from indican in that the former is not de- composed by boiling with alkalies, and does not yield any glucose-like substance on decomposition ; the latter is almost immediately decom- posed by boiling alkaline solutions, and, under the influence of acids and of certain ferments, yields, besides indigo-blue, indiglucin, a sweet, non- fermentable substance, which reduces Fehling’s solution. Uroxanthin is a normal constituent of human urine, but is much in- creased in the first stage of cholera, in cases of cancer of the liver, Addi- son’s disease, and intestinal obstruction. It has also been detected in the perspiration. In examining the color of urine it should be rendered strongly acid with N03H or HC1, and allowed to stand six hours to liberate combined pig- ment, and then examined by transmitted light in a beaker three inches in diameter. Melanin is the black pigment of the choroid, melanotic tumors, and skin of the negro ; and occurs pathologically in the urine and deposited in the air-passages. 272 MANUAL OF CHEMISTRY. SILICON. Symbol = Si—Atomic weight = 28—Molecular weight = 56 (?)—Discovered by Davy 1807—Name from silex =flint. Also known as silicium ; occurs in three allotropic forms : Amorphous silicon, formed when silicon chloride is passed over heated K or Na, is a dark brown powder, heavier than water. When heated in air it burns with a bright flame to the dioxide. It dissolves in potash and in hydro- fluoric acid, but is not attacked by other acids. Graphitoid silicon is ob- tained by fusing potassium fluosilicate with aluminium. It forms hexag- onal plates, of sp. gr. 2.49, which do not burn when heated to whiteness in O, but may be oxidized at that temperature by a mixture of potassium chlorate and nitrate. It dissolves slowly in alkaline solutions, but not in acids. Crystallized silicon, corresponding to the diamond, forms crystalline needles, which are only attacked by a mixture of nitric and hydrofluoric acids. Silicon, although closely related to C, exists in nature in but few com- pounds ; it has been caused to form artificial combinations, however, which indicate its possible capacity to exist in substances corresponding to those C compounds vulgarly known as organic, e.g., silicichloroform and silicibromoform, SiHCl„ and SiHBr,. Hydrogen silicide—SiH4—32—is obtained as a colorless, insoluble, spontaneously inflammable gas, by passing the current of a galvanic bat- tery of twelve cells through a solution of common salt, using a plate of aluminium, alloyed with silicon, as the positive electrode. Silicon chloride—SiCl4—170—a colorless, volatile liquid, having an irritating odor ; sp. gr. 1.52 ; boils at 59° (138°.2 F.); formed when Si is heated to redness in Cl. Silicic oxide—Silicic anhydride—Silex—SiO„—60 —is the most im- portant of the compounds of silicon. It exists in nature in the different varieties of quartz, and in the rocks and sands containing that mineral, in agate, carnelian, flint, etc. Its purest native form is rock crystal; its hy- drates occur in the opal, and in solution in natural waters. When crys- tallized it is fusible with difficulty ; when heated to redness with the alka- line carbonates it forms silicates, which solidify to glass-like masses on cooling. It unites with H20 to form a number of acid hydrates. The normal hydrate, Si04H4, has not been isolated, although it probably exists in the solution obtained by adding an excess of HC1 to a solution of sodium silicate. A gelatinous hydrate, soluble in wrater and in acids and alkalies, is obtained by adding a small quantity of IIC1 to a concentrated solution of sodium silicate. Hydrofluosilicic acid—SiFfH3—144—is obtained in solution by passing the gas disengaged by gently heating a mixture of equal parts of fluorspar and pounded glass, and 6 pts. S04H2, through water ; the dis- engagement tube being protected from moisture by a layer of mercury. It is used in analysis as a test for K and Na. VANADIUM AND MOLYBDENUM GROUPS. 273 VI. VANADIUM GROUP. Y anadium—Niobium—Tantalum. The elements of this group resemble those of the N group, but are more distinctly quadrivalent; par- ticularly Nb and Ta. / Vanadium—V—51.3—a brilliant, crystalline metal; sp. gr. - 5.5 ; which forms a series of oxides similar to those of N. No salts of V are known, but salts of vanadyl (VO) are numerous, and are used in the manu- facture of aniline black. Niobium—Nb—94—a bright, steel-gray metal; sp. gr. 7.06 ; which burns in air to Nb205 and in 01 to NbCl5; not attacked by acids. Tantalum—Ta—182—closely resembles Nb in its chemical characters. VII. MOLYBDENUM (TROUP. Molybdenum—Tungsten—Osmium. The position of this group is doubtful; and it is probable that the lower oxides will be found to be basic in character: in which case the group should be transferred to the third class. Molybdenum—Mo—95.5—a brittle white metal. The oxide Mo03, molybdic anhydride, combines with H20 to form a number of acids ; the ammonium salt of one of which is used as a reagent for P04H3 ; with which it forms a conjugate acid, phosphomolybdic acid, used as a reagent for the alkaloids. Tungsten—Wolfram—W—183.6—a hard, brittle metal; sp. gr. 17.4. The oxide, W03, tungstic anhy- dride, is a yellow powder, forming with H20 several acid hydrates; one of which, metatungstic acid, is used as a test for the alkaloids, as are also the conjugate silicotungstic and phosphotungstic acids. Tissues impregnated with sodium tungstate are rendered uninflammable. Osmium—Os—198.5 —occurs in combination with Ir in Ptores: combustible and readily oxidized to 0s04. This oxide, known as osmic acid, forms colorless crystals, soluble in H20, which give off intensely irritating vapors. It is used as a staining agent by histologists, and also in dental practice. 274 MANUAL OF CHEMISTRY. CLASS m.—AMPHOTERIC ELEMENTS. Elements whose Oxides Unite with Water, some to form Bases, OTHERS TO FORM ACIDS. WHICH FORM OxVSALTS. I. GOLD GROUP. GOLD. Symbol — Au (AURUM)—Atomic weight — 196.2—Molecular weight — 392.4 (?)—sp. gr. = 19.258-19.367—Fuses at 1200° (2192° F.). This, the only member of the group, forms two series of compounds; in one, AuCl, it is univalent; in the other, AuC13, trivalent. Its hydrate, auric acid, Au (OH)3, corresponds to the oxide Au203. Its oxysalts are unstable. It is yellow or red by reflected light, green by transmitted light, reddish-purple when finely divided ; not very tenacious ; softer than sil- ver ; very malleable and ductile. It is not acted on by HO or air at any temperature, nor by any single acid. It combines directly with Cl, Br, I, P, Sb, As, and Hg. It dissolves in nitromuriatic acid as auric chloride. It is oxidized by alkalies in fusion on contact with air. Auric chloride— Gold trichloride—AuC13—302.7—obtained by dis- solving Au in aqua regia, evaporating at 100° (212° F.), and purifying by crystallization from HaO. Deliquescent yellow prisms, very soluble in H20, alcohol and ether ; readily decomposed with separation of Au, by contact with P, or with reducing agents. Its solution, treated with the chlorides of tin, deposits a purple double stannate of Sn and Au, called “purple of cassius.” With alkaline chlorides it forms double chlorides, chloraurates (auri et sodii chloridum, U.S.). Analytical Characters. (1.) With H2S, from neutral or acid solution, a blackish-brown ppt. in the cold ; insoluble in N03H and HC1; soluble in aqua regia and in yel- low NH4HS. (2.) With stannous chloride and a little chlorine water, a purple-red ppt., insoluble in HC1. (3.) With ferrous sulphate a brown deposit, which assumes the lustre of gold when dried and burnished. n. IRON GROUP. Chromium—Manganese—Iron. The elements of this group form two series of compounds : in one they are bivalent, as in Fe"Cla or S04Mn", while in the other they are quad- CHROMIUM. 275 rivalent; but when quadrivalent the atoms do not enter into combination crj- singly, but grouped two together to form a hexavalentunit as in (Fe2)vlCl6, (Cr2)vl03. They form several oxides ; of which the oxide M03 is an anhydride, corresponding to which are acids and salts; most of the other oxides are basic. CHROMIUM. Symbol = Cr—Atomic weight = 52.4—Molecular weight = 104.8 (?)— Sp. gr. = 6.8—Discovered by Vauquelin, 1797—Name from xp^ya — color. The element is separated with difficulty by reduction of its oxide by charcoal, or of its chloride by sodium. It is a hard, crystalline, almost infusible metal. Combines with O only at a red heat; it is not attacked by acids, except HC1; is readily attacked by alkalies. Chromic Oxide—Sesquioxide, or green oxide of chromium—Cr, 03— 152.8—obtained, amorphous, by calcining a mixture of potassium dichro- mate and starch, or, crystallized, by heating neutral potassium chromate to redness in Cl. It is green ; insoluble in H20, acids, and alkalies ; fusible with diffi- culty, and not decomposed by heat; not reduced by H. At a red heat in air, it combines with alkaline hydrates and nitrates to form chromates. It forms two series of salts, the terms of one of which are green, those of the other violet. The alkaline hydrates separate a bluish green hydrate from solutions of the green salts, and a bluish violet hydrate from those of the violet salts. Chromium green, or emerald green, is a green hydrate, formed by de- composing a double borate of chromium and potassium by HO. It is used in the arts as a substitute for the arsenical greens, and is non- poisonous. Chromic Anhydride—Acidum chromicum (U. S.)—Cr03—100.4—is formed by decomposing a solution of potassium dichromate by excess of S04H2, and crystallizing. It crystallizes in deliquescent crimson prisms, very soluble in H20 and in dilute alcohol. It is a powerful oxidant, capable of igniting strong alcohol. The true chromic acid has not been isolated, but salts are known which correspond to three acid hydrates : Cr04H2 = chromic acid ; Cr207H2 = dichromic add; and Cr301(1H2 = trichromic acid. Chlorides.—Two chlorides and one oxychloride of chromium are known. Chromous chloride, CrCl2, is a white solid, soluble with a blue color in H O. Chromic chloride, (Cr2)ClG, forms large, red crystals, in- soluble in H20 when pure. Sulphates.—A violet sulphate crystallizes in octahedra, (S04)3(Cr)2 -f 15 Aq, and is very soluble in H20 ; at 100 it is converted into a green salt, (S04)3(Cr)2+5 Aq, soluble in alcohol; which at higher temperatures is converted into the red, insoluble, anhydrous salt. Chromic sulphate forms double sulphates, containing 24 Aq, with the alkaline sulphates. (See Alums.) 276 MANUAL OF CHEMISTRY. Analytical Characters. Chromotxs Salts.—(1.) Potash, a brown ppt. (2.) Ammonium hydrate, greenish white ppt. (3.) Alkaline sulphides, black ppt. (4.) Sodium phosphate, blue ppt. Chromic Salts.—(1.) Potash, green ppt.; an excess of precipitant forms a green solution, from which Cr203 separates on boiling. (2.) Ammonium hydrate, greenish-gray ppt. (3.) Ammonium sulphydrate, greenish ppt. Chromates.—(1.) H2S in acid solution, brownish color, changing to green. (2.) Ammonium sulphydrate, greenish ppt. (3.) Barium chloride, yellowish ppt. (4.) Silver nitrate, brownish-red ppt., soluble in N03H or NH4HO. (5.) Lead acetate, yellow ppt., soluble in potash, insoluble in acetic acid. Action on the Economy. Chromic anhydride oxidizes organic substances, and is used as a caustic. The chromates, especially potassium dichromate (q. v.), are irritants, and have a distinctly poisonous action as well. Workmen handling the dichromate are liable to a form of chronic poisoning. In acute chromium-poisoning, emetics, and subsequently magnesium carbonate in milk, are to be given. MANGANESE. Symbol = Mn—Atomic weight = 54—Molecular weight = 108 (?)—Sp. gr. = 7.138-7.206. A hard, grayish, brittle metal; fusible with difficulty ; obtained by reduction of its oxides by C at a white heat. It is not readily oxidized by cold, dry air; but is superficially oxidized when heated. It decomposes H20, liberating H ; and dissolves in dilute acids. Compounds of Manganese. Oxides.—Manganese forms six oxides or compounds representing them : Manganous oxide, MnO ; manganoso-manganic oxide, Mn304 ; man- ganic oxide, Mn.,03 ; permanganic oxide, MnO„, and permanganic anhydride, Mn„07, are known free. Manganic anhydride, MnOs, has not been iso- lated. MnO and Mn,,03 are basic ; Mn304 and Mn02 are indifferent oxides ; and Mn03 and Mn207 are anhydrides, corresponding to the manganates and permanganates. Permanganic Oxide.—Manganese dioxide, or black oxide—Mangani oxi- dum nigrum (TJ. S.)—Manganesii ox. nig. (Hr.)—MnO,—86—exists in nature as pyrolusite, the principal ore of manganese, in steel gray or brownish-black, imperfectly crystalline masses. IRON. 277 At a red heat it loses 12 per cent, of O : 3Mn02 = Mn304 + 02 ; and at a white heat a further quantity of O is given off: 2Mn304 = 6MnO + 02. Heated with S04H2 it gives off O and forms manganous sulphate: 2Mn02 2S04H, = 2S04Mn 4- 2H..0 + 02. With HC1 it yields manganous chlo- ride, H„0 and Cl: Mn02 + 4HC1 = MnCla + 2H,0 -+- Cl2. It is not acted on by N03H. Chlorides.—Two chlorides of Mn are known : manganous chloride, MnCl2, a pink, deliquescent, soluble salt, occurring, mixed with ferric chloride, in the waste liquid of the preparation of Cl; and manganic chloride, Mn2Cl, Salts of Manganese. Manganese forms two series of salts : Manganous salts, containing Mn"; and manganic salts, containing (Mn2)vi ; the former are colorless or pink, and soluble in water ; the latter are unstable. Manganous Sulphate.—Mangani sulphas (U. S.)—S04Mn+wAq—150 -fnl8—is formed by the action of S04H, on MnOa. Below 6° (42°.8 F.) it crystallizes with 7 Aq, and is isomorphous with ferrous sulphate ; between 7°-20° (44°.6-68° F.) it forms crystals with 5 Aq, and is isomorphous with cupric sulphate ; between 20°-30° (68°-86° F.) it crystallizes with 4 Aq. It is rose-colored, darker as the proportion of Aq increases, soluble in H,0, insoluble in alcohol. With the alkaline sulphates it forms double salts, with 6 Aq. Analytical Characters. Manganous.—(1.) Potash, white ppt., turning brown. (2.) Alkaline carbonates, white ppts. (3.) Ammonium sulphydrate, flesh-colored ppt., soluble in acids, spar- ingly soluble in excess of precipitant. (4.) Potassium ferrocyanide, faintly reddish white ppt., in neutral solu- tion ; soluble in HC1. (5.) Potassium cyanide, rose-colored ppt., forming brown solution with excess. Manganic.—(1.) H,S, ppt. of sulphur. (2.) Ammonium sulphydrate, flesh-ccflored ppt. (3.) Potassium ferrocyanide, greenish ppt. (4.) Potassium ferricyanide, brown ppt. (5.) Potassium cyanide, light brown ppt. Manganates—are green salts, whose solutions are only stable in pres- ence of excess of alkali, and turn brown when diluted and acidulated. Permanganates—form red solutions, which are decolorized by S02, other reducing agents, and many organic substances. IRON. Symbol- Fe (FERRUM) —Atomic weight = 55.9—Molecular weight = 111.8 ?—Sp. gr. = 7.25-7.9 Fuses at 1600° (1912° F.)—Name from the Saxon, iren. Occukrence.—Free in small quantity only in platinum ores and me- teorites. As Fe203 in red hcematite and specular iron; as hydrates of Fe203 in brown hcematite and oolitic iron ; as Fe„04 in magnetic iron ; as 278 MANUAL OF CHEMISTRY. C03Fe in spathic iron, clay ironstone and hog ore ; and as FeS2 in pyrites. It is also a constituent of most soils and clays, exists in many mineral waters, and in the red blood pigment of animals. Preparation.—In working the ores, reduction is first effected in a blast-, furnace, into which alternate layers of ore, coal, and limestone are fed from the top, while air is forced in from below. In the lower part of the furnace C02 is produced at the expense of the coal; higher up it is re- duced by the incandescent fuel to CO, which at a still higher point reduces the ore ; the fused metal so liberated collects at the lowest point under a layer of slag, and is drawn off to be cast as pig iron. This product is then purified by burning out impurities, in the process known as puddling. Pure iron is prepared by reduction of ferrous chloride or of ferric oxide by H at a temperature approaching redness. Varieties.—Cast iron is a brittle, white or gray, crystalline metal, con- sisting of Fe 89-90$ ; C 1-4.5$ ; and Si, P, S, and Mn. As pig iron, it is the product of the blast-furnace. Wrought or bar iron is a fibrous, tough metal, freed in part from the impurities of cast iron by refining and puddling. Steel is Fe combined with a quantity of C less than that existing in cast, and greater than that in bar iron. It is prepared by cementation ; which consists in causing bar iron to combine with C ; or by the Bessemer method ; which, as now used, consists in burning the C out of molten cast iron, to which the proper proportion of C is then added in the shape of spiegel eisen, an iron rich in Mn and C. The purest forms of commercial iron are those used in piano-strings, the teeth of carding machines, and electro-magnets ; known as soft iron. Reduced iron—Ferrum reductum (U. S.)—Fer. red actum (Br.)—is Fe, more or less mixed with Fe203 and Fe304, obtained by heating Fe203 in H. Properties.—Physical.—Pure iron is silver-white ; quite soft; crystal- lizes in cubes or octaliedra. Wrought iron is gray, hard; very tenacious ; fibrous; quite malleable and ductile ; capable of being welded ; highly magnetic but only temporarily so. Steel is gray ; very hard and brittle if tempered, soft and tenacious if not ; permanently magnetic. Chemical.—Iron is not altered by dry air at the ordinary temperature. At a red heat it is oxidized. In damp air it is converted into a hydrate ; iron rust. Tinplate is sheet iron, coated with tin ; galvanized iron is coated with zinc, to preserve it from the action of damp air. Iron unites directly with Cl, Br, I, S, N, P, As, and Sb. It dissolves in HC1 as ferrous chloride, while H is liberated. Heated with strong S04H,, it gives off S02 ; with dilute SOH2, H is given off and ferrous sulphate formed. Dilute NO,H dissolves Fe, but the concentrated acid renders it passive, when it is not dissolved by either concentrated or dilute NO.H, until the passive condition is destroyed by contact with Pt, Ag or Cu, or by heating to 40° (104° F.). Compounds of Iron. Oxides.—Three oxides of iron exist free : FeO ; Fe203; Fe304. Ferrous Oxide—Protoxide of iron—FeO—71.9—is formed by heating Fea03 in CO or C02. Ferric Oxide—Sesquioxide or peroxide of iron—Colcothar—Jeweller’s rouge—Venetian red—Fe„0?—159.8—occurs in nature (see above); and is formed when ferrous sulphate is strongly heated, as in the manufacture of 279 COMPOUNDS OF IRON. pyrosulphuric acid. It is a reddish, amorphous solid, is a weak base, and is decomposed at a white heat into O and Fe304. Magnetic Oxide—Black oxide—Ferri oxidum magneticum (Br.)—Fe304 —231.7—is the natural loadstone, and is formed by the action of air or steam upon iron at high temperatures. It is probably a compound of ferrous and ferric oxides (FeO, Fe203), as acids produce with it mixtures of ferrous and ferric salts. Hydrates.—Ferrous.—When a solution of a ferrous salt is decom- posed by an alkaline hydrate, a greenish-white hydrate, FeH202, is de- posited ; which rapidly absorbs O from the air, with formation of ferric hydrate. Ferric.—When an alkali is added to a solution of a ferric salt, a brown, gelatinous precipitate is formed, which is the normal ferric hydrate, (Fe)2 H6Ofi = Ferri peroxidum hydratum (U. S.); Fer. perox. humidum (Br.). It is not formed in the presence of fixed organic acids, or of sugar in suffi- cient quantity. If preserved under H20 it is partly oxidized, forming an oxyhydrate which is incapable of forming ferrous arsenate with As203. If the hydrate (Fe2)H#06 be dried at 100° (212° F.), it loses 2H20, and is converted into (Fe )0 , HO, which is the Ferri peroxidum hydratum (Br.). If the normal hydrate be dried in vacuo it is converted into (Fe 2)2H609, and this, when boiled for some hours with H20, is converted into the col- loid, or modified hydrate (Fe2)H204 (?), which is brick-red in color; almost insoluble in N03H and HC1; gives no Prussian blue reaction, and forms a turbid solution with acetic acid. If recently precipitated ferric hydrate be dissolved in solution of ferric chloride or acetate, and subjected to dialysis, almost all the acid passes out, leaving in the dialyzer a dark-red solution, which probably contains this colloid hydrate, and which is instantly coag- ulated by a trace of S04H2, by alkalies, many salts, and by heat (dialyzed iron). Ferric Acid—Fe204H„.—Neither the free acid nor the oxide, FeO,,, are known in the free state ; the ferrates, however, of Na, K, Ba, Sr, and Ca are known. Sulphides.—Ferrous Sulphide—Protosulphide of iron—FeS—87.9—is formed : (1) By heating a mixture of finely divided Fe and S to redness ; (2) by pressing roll sulphur on white hot iron ; (3) in a hydrated condi- tion, FeS, H20, by treating a solution of a ferrous salt with an alkaline sulphydrate. The dry sulphide is a brownish, brittle, magnetic solid ; insoluble in H20, soluble in acids with evolution of H2S. The hydrate is a black pow- der, which absorbs O from the air, turning yellow, by formation of Fe203, and liberation of S. It occurs in the faeces of persons taking chalybeate waters or preparations of iron. Ferric Sulphide—Sesquisulphide—Fe2S3—207.8—occurs in nature in copper pyrites and is formed when the disulphide is heated to redness. Ferric Disulphide—FeS2—119.9—occurs in the white and yellow Mar- tial pyrites used in the manufacture of S04H„. When heated in air it is decomposed into SO„ and magnetic pyrites: 3FeS2 + 202 = Fe,,S4 +2S02. Chlorides.—Ferrous Chloride—Protochloride—FeCl„—129.9—is pro- duced : (1) by passing dry HC1 over red hot Fe ; (2) by heating ferric chloride in H ; (3) as a hydrate, FeCl2, 4H20, by dissolving Fe in HC1. The anhydrous compound is a yellow, crystalline, volatile, and very solu- ble solid ; the hydrated is in greenish, oblique rhombic prisms, deliques- 280 MANUAL OF CHEMISTRY. cent and very soluble in H20 and alcohol. "When heated in air it is con- verted into ferric chloride and an oxychloride. Ferric Chloride—Sesquichloride—Perchlonde—Ferri chloridum (U. S.) —Fe2Cl6—324.8—is produced in the anhydrous form by heating Fe in Cl. As a hydrate, Fe2Clr,4H, 0 or Fe2Cl,6H20 ; it is formed : (1) by so- lution of the anhydrous compound ; (2) by dissolving Fe in aqua regia ; (3) by dissolving ferric hydrate in HC1; (4) by the action of Cl or of NOsH on solution of ferrous chloride. It is by the last method that the pharma- ceutical product is obtained. The anhydrous compound forms reddish-violet, crystalline plates, very deliquescent. The hydrates form yellow, nodular, imperfectly crystalline masses, or rhombic plates, very soluble in H.,0, soluble in alcohol and ether. In solution it is converted into FeCl2 by reducing agents. The Liq. ferri chloridi (U. S.) — Liq. fer. perchloridi (Br.) is an aqueous solu- tion of this compound, containing excess of acid. The Tinct.fer. chlor. (U. S.) and Tinct.fer. perchl. (Br.) are the solution diluted with alcohol; and contain ethyl chloride and ferrous chloride. Bromides.—Ferrous Bromide—FeBr2—215.9—is formed by the ac- tion of Br on excess of Fe in presence of H„0. Ferric Bromide—Fe2Br6—591.8—is prepared by the action of excess of Br on Fe. Iodides.—Ferrous Iodide—Ferriiodidum (U. S.; Br.)—Fel„—309.9— is obtained, with 4H20, by the action of I upon excess of Fe in the pre- sence of warm H20. When anhydrous, it is a white powder ; hydrated, it is in green crystals. In air it is rapidly decomposed, more slowly in the presence of sugar. Ferric Iodide—Fe2I6—873.8—is formed by the action of excess of I on Fe. Salts of Iron. Sulphates.—Ferrous Sulphate — Protosulphate—Green vitriol—Cop- peras—Ferri sulphas (U. 8.; Br.)—S04Fe + 7 Aq—151.9 + 126—is formed : (1) by oxidation of the sulphide, Fe.tS4, formed in the manu- facture of S04H3 ; (2) by dissolving Fe in dilute S04H2. It forms green, efflorescent, oblique rhombic prisms, quite soluble in HaO, insoluble in alcohol. It loses 6 Aq at 100° (212 F.) (Ferr. sulph. exsiccatus U. S.); and the last Aq at about 300° (572° F.). At a red heat it is decomposed into Fe203, S02 and S03. By exposure to air it is gradually converted into a basic ferric sulphate, (S04)3(Fe2),5Fe203. Ferric Sulphates are quite numerous, and are formed by oxidation of ferrous sulphate under different conditions. The normal sulphate, (S04)3 (Fe2), is formed by treating solution of SO,Fe with N03H, and evaporat- ing, after addition of one molecule of S04H2 for each two molecules of S04Fe. The Liq. fer. tersulphatis (U. S.) contains this salt. It is a yel- lowish-white, amorphous solid. Of the many basic ferric sulphates, the only one of medical interest is Monsel's salt, 5(S04)3(Feo) + 4Fe203, which exists in the Liq. ferri subsul- phatis (U. S.) and Liq. fer. persulphatis (Br.). Its solution is decolorized, and forms a white deposit with excess of S04H2. Nitrates.—Ferrous Nitrate— (NOs)2Fe —179.9—a greenish, unstable salt, formed by double decomposition between barium nitrate and ferrous sulphate ; or by the action of NOaH on FeS. Ferric Nitrates.—The normal nitrate — (NOs)6(Fe2)- 483.8—is ob- SALTS OF IROIL 281 tainecl in solution by dissolving Fe in NO.,H of sp. gr. 1.115 ; or by dis- solving ferric hydrate in NOaH. It therefor exists in the Liq. ferri nitratis (U. S.). It crystallizes in rhombic prisms with 18 Aq, or in cubes with 12 Aq. Several basic nitrates are known, all of which are uncrystallizable, and by their presence (as when Fe is dissolved in N03H to saturation) prevent the crystallization of the normal salt. Phosphates.—Triferrous Phosphate.—(P04).,Fe.—357.7.—A white precipitate, formed by adding disodic phosphate to a solution of a ferrous salt, in presence of sodium acetate. By exposure to air it turns blue ; a part being converted into ferric phosphate. The ferri phosphas (Br.), is such a mixture of the two salts. It is insoluble in H20 ; sparingly solu- ble in H20 containing carbonic or acetic acid. It is probably this phosphate, capable of turning blue, which some- times occurs in the lungs in phthisis, in blue pus, and in long buried bones. Ferric Phosphate— (P04)„(Fe.) —301.8—is produced by the action of an alkaline phosphate on ferric chloride. It is soluble in HC1, N03H, citric and tartaric acids, insoluble in phosphoric acid and in solution of liydrosodic phosphate. The ferri phosphas (U. S.) is a compound, or mixture of this salt with disodic citrate, which is soluble in water. There exist quite a number of basic ferric phosphates. Ferric Pyrophosphate—(P„07)3(Fe2)2—745.6—is precipitated by de- composition of a solution of a ferric compound by sodium pyrophosphate ; an excess of the Na salt dissolves the precipitate when warmed, and, on evap- oration, leaves scales of a double salt, (P207)3(Fe2)2, (P207)2 Nas + 20 Aq. The ferri pyrophosphas (U. S.) is probably a mixture, or compound (?) of ferric pyrophosphate, trisodic citrate, and ferric citrate. Acetates.—Ferrous Acetate—(C2H303)2Fe—173.9—is formed, by de- composition of ferrous sulphate by calcium acetate, in soluble, silky needles. Ferric Acetates.—The normal salt, (C2H302)c,(Fe2), is obtained by adding slight excess of ferric sulphate to lead acetate, and decanting after twenty-four hours. It is dark red, uncrystallizable, very soluble in alco- hol and in H ,0. If its solution be heated it darkens suddenly, gives off acetic acid, and contains a basic acetate ; when boiled it loses all its acetic acid and deposits ferric hydrate ; when heated in closed vessels to 100° (212° F.), and treated with a trace of mineral acid, it deposits the modified ferric hydrate. Ferrous Carbonate—C03Fe—115.9—occurs as an ore of iron, and is obtained in a hydrated form by adding an alkaline carbonate to a ferrous salt. It is a greenish, amorphous powder, which, on exposure to air, turns red by formation of ferric hydrate ; a change which is retarded by the pre- sence of sugar, hence the addition of that substance in the ferri carbonas saccharatus (U.S.; Br.). It is insoluble in pure H,0, but soluble in H O containing carbonic acid, probably as ferrous bicarbonate, (C03)2H2Fe, in which form it occurs in chalybeate waters. Ferrous Lactate—Ferri lactas(U. S.)—(C3HfOa)2Fe->-3 Aq—233.9 + 54—is formed when iron filings are dissolved in lactic acid. It crystallizes in greenish-yellow needles ; soluble in H20 ; insoluble in alcohol; perma- nent in air when dry. Ferrous Oxalate—Ferri oxalas (U. S.)—C,0,Fe + Aq—143.9 + 36 —is a yellow, crystalline powder ; sparingly soluble in H20 ; formed by dissolving iron filings in solution of oxalic acid. 282 MANUAL OP CHEMISTRY. Tartrates.—Ferrous Tartrate—C4H4OeFe + 2 Aq—203.9 + 36.—A white, crystalline powder ; formed by dissolving Fe in hot concentrated solution of tartaric acid. Ferric Tartrate—(C4H406)3Fe2 + 3 Aq—555.8 -+- 54.—A dirty yellow, amorphous mass, obtained by dissolving recently precipitated ferric hy- drate in tartaric acid solution, and evaporating below 50° (122° F.). A number of double tartrates, containing the group (Fe202)" are also known. Such are: Ferrico-ammonic tartrate = ferri et ammonii tartras (E S.), (C.H.O.yFeA), (NH.) + 4 Aq, and Ferrico-potassic tartrate = ferri etpotassii tartras (U. /S'.),(C4H40fi)2(Fe202)K2. They are prepared by dissolving recently precipitated ferric hydrate in hot solutions of the hydro- alkaline tartrate. They only react with ferro- and sulphocyanides after ad- dition of a mineral acid. Citrates.—Ferric Citrate—Ferri citras (£7. 8.)—(CrH507)2(Fe.2) + 6 Aq—489.8 + 108—is in garnet-colored scales, obtained by dissolving fer- ric hydrate in solution of citric acid and evaporating the solution at about 60° (140° F.). It loses 3 Aq at 120° (248° F.), and the remainder at 150° (302° F.). If a small quantity of ammonia be added before the evapora- tion, the product consists of the modified citrate = ferri et ammonii citras {U. S.), which only reacts with potassium ferrocyanide after addition of HC1. The various citrates of iron and alkaloids are not definite compounds. Ferric Ferrocyanide—Prussian blue—(FeC(.N6)3(Fe2)2 + 18 Aq— 859.3 + 324—is a dark blue precipitate, formed when potassium ferrocy- anide is added to a ferric salt. It is insoluble in H20, alcohol and di- lute acids ; soluble in oxalic acid solution (blue ink). Alkalies turn it brown. Ferrous Ferricyanide—Turnbull’s blue— (Fe2C]2N12)Fe3 + n Aq —591.5 + n 18—is a dark-blue substance produced by the action of po- tassium ferricyanide on ferrous salts. Heated in air it is converted into Prussian blue and ferric oxide. Analytical Characters. Ferrous.—Are acid ; colorless when anhydrous ; pale green when hy- drated ; oxidized by air to basic ferric compounds. (1.) Potash : greenish-white ppt.; insoluble in excess ; changing to green or brown in air. (2.) Ammonium hydrate : greenish ppt.; soluble in excess ; not formed in presence of ammoniacal salts. (3.) Ammonium sulphydrate : black ppt.; insoluble in excess ; soluble in acids. (4.) Potassium ferrocyanide (in absence of ferric salts): white ppt.; turning blue in air. (5.) Potassium ferricyanide : blue ppt.; soluble in KHO ; insoluble in HC1. Ferric—Are acid, and yellow or brown. (1.) Potash or ammonium hydrate : voluminous, red-brown ppt.; insol- uble in excess. (2.) Hydrogen sulphide: in acid solution ; milky ppt. of sulphur; ferric reduced to ferrous compound. (3.) Ammonium sulphydrate : black ppt; insoluble in excess ; soluble in acids. ALUMINIUM. 283 (4) Potassium ferrocyanide : dark-blue ppt.; insoluble inHCl; soluble in KHO. (5.) Potassium sulphocyanate : dark red color ; prevented by tartaric or citric acid ; discharged by mercuric chloride. (6.) Tannin : blue-black color. HI. ALUMINIUM GROUP. Glucinium—Aluminium—Scandium—Gallium—Indium. This group is placed in the third class by virtue of the existence of the aluminates, and of the relations between the compounds of these ele- ments and some of those of the previous group. They form, however, but one series of compounds, corresponding to the ferric, containing the group (MJTi. No acids or salts of the members of the group, other than aluminium, are known ; yet their resemblances in other points are such as to forbid their separation. GLUCINIUM. Symbol = G1 or Be (Beryllium)—Atomic weight = 9—Sp. gr. — 2.1. A rare element occurring In the emerald and beryl. The metal resembles aluminium and its com- pounds resemble those of Al, and, in some respects, those of Mg. Its soluble salts are sweet in taste (yAvicuc = sweet). ALUMINIUM. Symbol = A1—Atomic weight — 27—Molecular weight — 55 (?)—sp. gr. = 2.56-2.67—Fuses at about 700° (1292° F.)—Name from alumen = alum —Discovered by Wohler, 1827. Occurrence.—Exceedingly abundant in the clays as silicate. Preparation.—(1.) By decomposing vapor of aluminium chloride by Na or K (Wohler). (2.) Aluminium hydrate, mixed with sodium chloride and charcoal, is heated in Cl, by which a double chloride of Na and A1 (2NaCl, A13C16) is formed. This is then heated with Na, when A1 and NaCl are produced. (The industrial process.) Properties.—Physical.—A bluish-white metal; hard ; quite malleable and ductile when annealed from time to time ; slightly magnetic ; a good conductor of electricity ; non-volatile ; very light, and exceedingly sonor- ous. Chemical.—It is not affected by air or O, except at very high tem- peratures, and then only superficially ; if, however, it contain Si, it burns readily in air, forming aluminium silicate. It does not decompose H O at a red heat; but in contact with Cu, Pt, or I it does so at 100° (212° F.). It combines directly with Bo, Si, Cl, Br, and I. It is attacked by HC1, gaseous or in solution, with evolution of H, and formation of Al2Clfi. It dissolves in alkaline solutions, with formation of aluminates, and liberation of H. It alloys with Cu to form a golden yellow metal (aluminium bronze). 284 MANUAL OF CHEMISTKY. Compounds of Aluminium. Aluminium Oxide—Alumina—A1203—102—occurs in nature, nearly pure, as corundum, emery, ruby, sapphire, and topaz ; and is formed arti- ficially by calcining the hydrate, or ammonia alum, at a red heat. It is a light, white, odorless, tasteless powder ; fuses with difficulty ; and, on cooling, solidifies in very hard crystals. Unless it have been heated to bright redness, it combines with H20, with elevation of tem- perature. It is almost insoluble in acids and alkalies. S04H2, diluted with an equal bulk of H20, dissolves it slowly as (S04)3(A12). Fused potash and soda combine with it to form aluminates. It is not reduced by charcoal. Aluminium Hydrate—Aluminii hydras (U. 8.)— A12H60(.—156—is formed when a solution of an aluminium salt is decomposed by an alkali, or alkaline carbonate. It constitutes a gelatinous mass, which, when dried, leaves an amorphous, translucid mass ; and when pulverized a white, tasteless, amorphous powder. When the liquid in which it is formed con- tains coloring matters, these are carried down with it, and the dried de- posits are used as pigments, called lacs. When freshly precipitated, it is insoluble in H20 ; soluble in acids and solutions of the fixed alkalies. When dried at a temperature above 50° (122° F.), or after 24 hours contact with the mother liquor, its solubility is greatly diminished. With acids it forms salts of aluminium ; and with alkalies, aluminates of the alkaline metal. Heated to near redness it is decomposed into A1203 and H20. A soluble modification is obtained by dialysing a solution of Al2HcOc in AlaCle, or by heating a dilute solution of aluminium acetate for 240 hours. Aluminates are for the most part crystalline, soluble compounds, obtained by the action of metallic oxides or hydrates upon alumina. Potas- sium aluminate, Al204Ka + 3Aq—is formed by dissolving recently precipi- tated aluminium hydrate in potash solution. It forms white crystals ; very soluble in H20, insoluble in alcohol; caustic and alkaline. By a large quantity of H20 it is decomposed into aluminium hydrate and a more alkaline salt, A1408K6. Sodium Aluminate.—The aluminate Al204Na2 is not known. That hav- ing the composition AI4OuNa6 is prepared by heating to redness a mixture of 1 pt. sodium carbonate and 2 pts. of a native ferruginous aluminium hydrate (beauxite). It is insoluble in H„0, and is decomposed by carbonic acid, with precipitation of aluminium hydrate. Aluminium Chloride—Al .Cl,—267—is prepared by passing Cl over a mixture of Al.O,, and C, heated to redness ; or by heating clay in a mix- ture of gaseous HC1 and vapor of CS2. It crystallizes in colorless, hexagonal prisms ; fusible ; volatile ; deli- quescent ; very soluble in H20 and in alcohol. From a hot, concentrated solution, it separates in prisms with 12 Aq. The disinfectant called chloralum is a solution of impure A12C16. Salts of Aluminium. Aluminium Sulphate—Aluminii sulphas (U. S.)—(S04),(A12) + 18 Aq—342 + 324—is obtained by dissolving A12H606 in S04H2; or (industri- ally) by beating clay with S04H2. It crystallizes with difficulty in thin, flexible plates; soluble in H,,0 ; very sparingly soluble in alcohol. Heated, it fuses in its Aq, which it ALUMINIUM. 285 gradually loses up to 200° (392° F.), when a white, amorphous powder, (504)3(A12), remains ; this is decomposed at a red heat, leaving a residue of pure alumina. Alums—are double sulphates of the alkaline metals, and the higher sulphates of this or the preceding group. When crystallized, they have the general formula : (S04)3(Ma)vi, S04B'2 + 24 Aq, in which (M.) may be (Fe,), (Mn,), (CrJ, (A1J, or (GaJ ; and R2 may be K2, Na2, Bb2, Cs2, Tl2, or (NH,)2. They are isomorphous with each other. Alumen (U. S.)—(S04)sA12, S04K2 + 24 Aq—516 + 432—is manufac- tured from “ alum shale,” and is formed when solutions of the sulphates of A1 and K are mixed in suitable proportion. It crystallizes in large, transparent, regular octahedra ; has a sweetish, astringent taste, and is readily soluble in H O. Heated, it fuses in its Aq at 92° (197.6° F.); and gradually loses 45.5 per cent, of its weight of H20 as the temperature rises to near redness. The product, known as burnt alum = alumen exsiccatum (U. S.), is (S04)3A1„,S04K2, and is slowly, but completely soluble in 20-30 pts. H.,0. At a bright red heat, SO„ and O are given off and A1203 and potassium sulphate remain ; at a higher temperature, potassium aluminate is formed. Its solutions are acid in re- action ; dissolve Zn and Fe with evolution of H ; and deposit A12H608 when treated with ammonium hydrate. Alumen (Br.)—(S04)3A12,S04(NH4)2 + 24 Aq—474 + 432—is the com- pound now usually met with as alum, both in this country and in England. It differs from potash alum in being more soluble in H20 between 20°-30° (68°-86° F.), and less soluble at other temperatures ; and in the action of heat upon it. At 92° (197°.6 F.) it fuses in its Aq; at 205° (401° F.) it loses its ammonium sulphate, leaving a white, hygroscopic substance, very slowly and incompletely soluble in H20. More strongly heated, it leaves alumina. Silicates—are very abundant in the different varieties of clay, feld- spar, albite, labradorite, mica, etc. The clays are hydrated aluminium silicates, more or less contaminated with alkaline and earthy salts and iron, to which last certain clays owe their color. The purest is kaolin, or porcelain clay, a white or grayish powder. They are largely used in the manufacture of the different varieties of bricks, terra cotta, pottery, and porcelain. Porcelain is made from the purer clays, mixed with sand and feldspar ; the former to prevent shrinkage, the latter to bring the mixture into partial fusion, and to render the product translucent. The fashioned articles are subjected to a first baking ; the porous, baked clay is then coated with a glaze, usually composed of oxide of lead, sand, and salt. During a second baking, the glaze fuses and coats the article with a hard, impermeable layer. The coarser articles of pottery are glazed by throwing sodium chloride into the fire ; the salt is volatilized, and, on con- tact with the hot aluminium silicate, deposits a coating of the fusible so- dium silicate, which hardens on cooling. Analytical Characters. (1.) Potash, or soda ; white ppt. ; soluble in excess. (2.) Ammonium hydrate ; white ppt.; almost insoluble in excess, es- pecially in presence of ammoniacal salts. (3.) Sodium phosphate; white ppt.; readily soluble in KHO and Na HO, but not in NH4HO; soluble in mineral acids, but not in acetic acid. 286 MANUAL OF CHEMISTRY. (4.) Blowpipe—on charcoal does not fuse, and moistened with cobalt nitrate solution turns dark sky-blue. SCANDIUM. Symbol — Sc—Atomic weight = 44.9—Discovered by Nilson (1879)—Name from Scandia. Occurs in minute traces in gadoiinite and euxenite. It forms an oxide, Sc2Oa ; a light, white, infusible powder; sp. gr. 3.8; resembling alumina. GALLIUM. Symbol = Ga—Atomic weight = 68.8—Sp. gr. = 6.9—Fuses at 36° (86° F.)—Name from Gallia—Dis- covered by Lecoq de Boisbaudran (1876). Occurs in very small quantity in certain zinc blendes. It is a hard, white metal; soluble in hot N03H, in HC1 and in KHO solution. In chemical characters it closely resembles A1; forms an oxide Gaa03, and a series of alums. The discovery of Sc and Ga afford most flattering verifications of predictions based upon purely theo- retical considerations. It has been observed that there exist numerical relations between the atomic weights of the elements, which, in groups of allied elements, differ from each other by (approximately) some multiple of eight. Upon this variation Mendelejeff has based what is known as the Periodic Law, to the effect that: “ The properties of elements, the constitution of their compounds, and the properties of the latter, are periodic functions of the atomic weights of the elements." In accordance with this law the elements may be thus arranged: Series. Group Group Group Group Group Group Group Group I. II. III. IY. V. VI. Y. VI. rh4 rh3 rh2 RH (R2H) (H04) R20 RO R2^3 ro2 RjO^ RO3 r2o7 1 H—1 2 Li—7 Be=9 B = ll C=12 N=14 0=16 F = 19 3 Na=23 Mg=24 Al=27 Si=28 P=31 S=32 Cl=36 Cu=63 Fe=56 4 K=39 Ca=40 Sc=44 Ti=48 V=61 Cr=62 Mn=56 Co=59 Ni = 59 5 (Cu=63) Rb=85 Zn=65 Ga=68 ?=72 As=75 Se=78 Br=80 Ru=104 Rh=104 Pd=106 Ag=108 6 Sr=87 Yt=88 Zr (?)=90 Kb=94 Mo=96 ? = 100 7 (Ag —108) Cs=133 Cd = 112 In-113 Sn=118 Sb=120 Fe=126 1=127 Os=195 8 Ba=137 D=138 (?) Ce=140 Pb=198 Au=196 9 10 E=178 (?) L=180 (?) Ta=182 W=184 ?=190 11 (Au = 196) Hg=200 Tl=204 Pb—207 Bi=208 12 Th=231 U=250 1 The atomic weights arm chemical characters, which were announced by Mendelejeff in 1870 as those of the undiscovered elements which would occupy the positions 4 and 5 in group III., have been since found to be those qf Sc and Ga. INDIUM. Symbol = In—Atomic weight = WZA—Sp. gr. = 1 At—Fuses at 170° (348°.8 P)—Discovered by Reich and Richter in 1863. A soft, silver-white, ductile metal, which occurs in small quantity in certain zinc blendes. It is charac- terized spectroscopically by two principal lines—X = 4511 and 4101. LEAD. 287 IV. URANIUM GROUP. URANIUM. This element is usually classed with Fe and Cr, or with Ni and Co. It does not, however, form com- pounds resembling the ferric; it forms a series of well-defined urancites, and a series of compounds of the radical uranyl (UOy. Standard solutions of its acetate or nitrate are used for the quantitative determina- tion of P04Hs. Symbol = Ur—Atomic weight — 238.5—Sp. gr. = 18.4—Discovered by Klaproth (1789). Y. LEAD GROUP. LEAD. Syrnbol - Pb (PLUMBUM) —Atomic weight = 206.9—Molecular weight = 413.8 (?)—Sp. gr. = 11.445—Fuses at 325° (617° F.)—Name from Iced = heavy (Saxon). Lead is usually classed with Cd, Bi, or Cu and Hg. It differs, how- ever, from Bi in being bivalent or quadrivalent, but not trivalent, and in forming no compounds resembling those of bismuthyl (BiO); from Cd, in the nature of its O compounds; and from Cu and Hg in forming no com- pounds similar to the mercurous and cuprous salts. Indeed, the nature of the Pb compounds is such that the element is best classed in a group by itself, which finds a place in this class by virtue of the existence of potas- sium plumbate. Occurrence.—Its most abundant ore is galena, PbS. It also occurs in white lead ore, in anglesite, SO,Pb, and in horn lead, PbCl,. Preparation.—Galena is first roasted with a little lime. The mixture of PbO, PbS, and S04Pb, so obtained, is strongly heated in a reverberatory furnace, when S02 is driven off. The impure work lead so formed is puri- fied by fusion in air and removal of the film of oxides of Sn and Sb. If the ore be rich in Ag, that metal is extracted by taking advantage of the greater fusibility of an alloy of Pb and Ag, than of Pb alone ; and subse- quent oxidation of the remaining Pb. Properties.—Physical.—It is a grayish white metal; brilliant upon freshly cut surfaces; very soft and pliable ; not very malleable or ductile ; crystallizes in octahedra ; a poor conductor of electricity ; a better con- ductor of heat. When expanded by heat it does not, on cooling, return to its original volume. Chemical.—When exposed to air it is oxidized, more readily and com- pletely at high temperatures. The action of H20 on Pb varies with the conditions : Pure unaerated H20 has no action upon it. By the combined action of air and moisture Pb is oxidized, and the oxide dissolved in the HO, leaving a metallic surface for the continuance of the action. The solvent action of H20 upon Pb is increased, owing to the formation of basic salts, by the presence of nitrogenized organic substances, nitrates, nitrites, and chlorides. On the other hand, carbonates, sulphates, and phosphates, by their tendency to form insoluble coatings, diminish the corroding action of H O. Carbonic acid in small quantity, especially in presence of carbonates, tends to preserve Pb from solution, while H„0 highly charged with it (soda water) dissolves the metal readily. Lead is dissolved, as the nitrate, by N03H. S04H2 when cold and moderately con- 288 MANUAL OF CHEMISTRY. centrated, does not affect it; but, when heated, dissolves it the more readily as the acid is more concentrated. It is attacked by HC1 of sp. gr. 1.12, especially if heated. Acetic acid dissolves it as acetate, or in the presence of CO„ converts it into white lead. Compounds of Lead. Oxides.—Lead Monoxide—Protoxide—Massicot—Litharge—Plumbioxi- dum (U. S. ; Br.)—PbO—222.9—is prepared by beating Pb or its carbo- nate or nitrate in air. If the product have been fused, it is litharge; if not, massicot. It forms copper-colored, mica-like plates, or a yellow pow- der ; or crystallizes from its solution in soda or potash in white, rhombic dodecahedra, or in rose-colored cubes. It fuses near a red heat, and vola- tilizes at a white heat; sp. gr. 9.277-9.5. It is sparingly soluble in H20, forming an alkaline solution. Heated in air to 300° (572° F.) it is oxidized to minium. It is readily reduced by H or C. With Cl it forms PbCl2 and O. It is a strong base ; decomposes alkaline salts, with liberation of the alkali. It dissolves in N03H and in hot acetic acid, as nitrate or acetate. When ground up with oils it saponifies the glycerin ethers, the Pb combining with the fatty acids to form Pb soaps, one of which, lead oleate, is the emplastrum plumbi (U. S. ; Br.). It also combines with the alkalies and earths to form plum- bites. Calcium plumbite, Pb,03Ca, is a crystalline salt, formed by heating PbO with milk of lime, and used in solution as a hair-dye. Plumboso-plumbic Oxide—Red oxide—Minium—Red lead—Pb304— 684.7—is prepared by heating massicot to 300° (572° F.) in air. It ordinarily has the composition Pb304, and has been considered as composed of PbO„ 2PbO ; or as a basic lead salt of plumbic acid, Pb03Pb, PIO. An orange- colored variety is formed when lead carbonate is heated to 300° (572° F.). It is a bright red powder, sp. gr. 8.62. It is converted into PbO when strongly heated, or by the action of reducing agents. NO.H changes its color to brown, dissolving PbO and leaving PbO,. It is decomposed by HC1, with formation of PbCl„ H.,0 and Cl. Lead Dioxide—Peroxide, or puce oxide, or broum oxide, or binoxide of lead—Plumbic anhydride—PbO„—238.9 — is prepared, either by dissolving the PbO out of red lead by dilute NO,H, or by passing a current of Cl through H,,0 holding lead carbonate in suspension. It is a dark, reddish-brown, amorphous powder ; sp. gr. 8.903-9.190 ; insoluble in H,0. Heated, it loses half its O and is converted into PbO. It is a valuable oxidant. It absorbs SO, to form S04Pb. It combines with alkalies to form plumbates, Pb03M2. Plumbic Acid—Pb03H„—256.9—forms crystalline plates, at the-(-elec- trode, when alkaline solutions of the Pb salts are decomposed by a weak current. Lead Sulphide—Galena—PbS—238.9—exists in nature. It is also formed by direct union of Pb and S ; by heating PbO with S or vapor of CS2 ; or by decomposing a solution of a Pb salt by H,S or an alkaline sul- phide. The native sulphide is bluish-gray, and has a metallic lustre ; sp. gr. 7.58 ; that formed by precipitation is a black powder ; sp. gr. 6.924. It fuses at a red heat and is partly sublimed, partly converted into a subsul- phate. Heated in air it is converted into S04 Pb, PbO and SO,. Heated SALTS OF LEAD. 289 in H it is reduced. Hot NOsH oxidizes it to S04Pb. Hot HC1 converts it into PbCl2. Boiling S04H2 converts it into S04Pb and S02. Lead Chloride—PbCl2—277.9—is formed by the action of Cl upon Pb at a red heat; by the action of boiling HC1 upon Pb ; and by double decomposition between a lead-salt and a chloride. It crystallizes in plates, or hexagonal needles ; sparingly soluble in cold H,0, less soluble in H,0 containing HC1; more soluble in hot H20, and in concentrated HC1. Several oxychlorides are known. Cassel, Paris, Verona, or Turner's yel- low is PbCl2,7PbO. Lead iodide—Plumbi iodidum (U. S. ; Br.)—Pbl2—460.9—is de- posited as a bright yellow powder, when a solution of potassium iodide is added to a solution of a Pb salt. Fused in air it is converted into an oxyiodide. Light and moisture decompose it, with liberation of I. It is almost insoluble in H20, soluble in solutions of ammonium chloride, so- dium hyposulphite, alkaline iodides, and potash. Salts of Lead. Nitrates.—Lead Nitrate—Plumbi nitras—(If. S. ; Br.)—(NOj Pb— 330.9—is formed by solution of Pb or of its oxides in excess of N03H. It forms anhydrous crystals ; soluble in H.,0. Heated, it is decomposed into PbO ; 6 and N„04. Besides the neutral nitrate, basic lead nitrates are known, which seem to indicate the existence of nitrogen acids similar to those of phosphorus ; (N04)3Pb 3—orthonitrate ; and N,,0_Pb2—pyronitrate. Lead Sulphate—S04Pb —302.9—is formed by the action of hot, con- centrated S04H2 on Pb ; or by double decomposition between a sulphate and a Pb salt in solution. It is a white powder ; almost insoluble in H„0 ; soluble in concentrated S04H , from which it is deposited by dilution. Lead Chromate—Chrome yellow—Cr04Pb—323.3—is formed by de- composing (N03)„Pb with potassium chromate. It is a yellow, amor- phous powder ; insoluble in J InO ; soluble in alkalies. Acetates—Neutral Lead Acetate—Salt of Saturn—Sugar of Lead— Plumbi acetas (If. S. ; Br.)—(C„H.,0„) Pb + 3 Aq—324.9 + 54—is formed by dissolving PbO in acetic acid ; or by exposing Pb in contact with acetic acid to air. It crystallizes in large, oblique rhombic prisms, sweetish, with a metal- lic after-taste ; soluble in H20 and alcohol; its solutions being acid. In air it effloresces, and is superficially converted into carbonate. It fuses at 75°.5 (167°.9 F.); loses Aq, and a part of its acid at 100° (212° F.), forming the sesquibasic acetate; at 280° (536° F.) it enters into true fusion, and, at a slightly higher temperature, is decomposed into CO„ ; Pb, and acetone. Its aqueous solution dissolves PbO, with formation of basic acetates. Sexbasic Lead Acetate—(C2H30„)Pb0H, 2PbO—728.7—is the main constituent of Goulard's extract — Liq. plumbi subacetatis (U. S. ; Br.), and is formed by boiling a solution of the neutral acetate with Pb in fine pow- der. The solution becomes milky on addition of ordinary H20 from formation of the sulphate and carbonate. Lead Carbonate—CO.,Pb—266.9—occurs in nature as cerusite; and is formed, as a white, insoluble powder, when a solution of a Pb com- 19 290 MANUAL OF CHEMISTRY. pound is decomposed by an alkaline carbonate, or by passing COa through a solution containing Pb. The plumbi carbonas (U. S. ; Br.), or white lead or ceruse, is a basic car- bonate, (C03Pb)2, PbH202—774.7—mixed with varying proportions of other basic carbonates. It is usually prepared by the action of C02 on a solution of the subacetate, prepared by the action of acetic acid on Pb and PbO. It is a heavy, white powder ; insoluble in H20, except in the pre- sence of C02; soluble in acids with effervescence; and decomposed by heat into C03 and PbO. Analytical Characters. (1.) Hydrogen sulphide, in acid solution : a black ppt. ; insoluble in alkaline sulphides, and in cold, dilute acids. (2.) Ammonium sulphydrate : black ppt. ; insoluble in excess. (3.) Hydrochloric acid : white ppt. ; in not too dilute solution ; solu- ble in boiling H20. (4.) Ammonium hydrate : white ppt. ; insoluble in excess. (5.) Potash ; white ppt. : soluble in excess, especially when heated. (6.) Sulphuric acid : white ppt.; insoluble in weak acids, soluble in solution of ammonium tartrate. (7.) Potassium iodide : yellow ppt. ; sparingly soluble in boiling H20; soluble in large excess. (8.) Potassium chromate : yellow ppt. ; soluble in KIIO solution. (9.) Iron or zinc separate the element from solutions of its salts. Action on the Economy. All the soluble compounds of Pb, and those which, although not solu- ble, are readily convertible into soluble compounds by H,0, air, or the digestive fluids, are actively poisonous. Some are also injurious by their local action upon tissues with which they come in contact; such are the acetate, and, in less degree, the nitrate. The chronic form of lead intoxication, painter's colic, etc., is purely poisonous, and is produced by the continued absorption of minute quan- tities of Pb, either by the sldn, lungs, or stomach. The acute form pre- sents symptoms referable to the local as well as to the poisonous action of the Pb salt, and is usually caused by the ingestion of a single dose of the acetate or carbonate. Metallic Pb, although probably not poisonous of itself, causes chronic lead-poisoning by the readiness with which it is converted into compounds capable of absorption. The sources of poisoning by metallic Pb are : the contamination of drinking water which has been in contact with the metal (see p. 50); the use of articles of food or of chewing tobacco which has been packed in tin-foil containing an excess of Pb ; the drinking of beer or other beverages which have been in contact with pewter ; or the hand- ling of the metal and its alloys. Almost all the compounds of Pb may produce painter’s colic. The carbonate, in painters, artists, manufacturers of white lead, and in persons sleeping in newly painted rooms ; the oxides, in the manufactures of glass, pottery, sealing-wax, and litharge, and by the use of lead-glazed pottery; BISMUTH. 291 by other compounds, by the inhalation of the dust of cloth factories, and by the use of lead hair-dyes. Acute lead-poisoning is by no means of as common occurrence as the chronic form, and usually terminates in reqovery. It is caused by the ingestion of a single large dose of the acetate, subacetate, carbonate, cr of red lead. In such cases the administration of magnesium sulphate is indicated ; it enters into double decomposition with the Pb salt to form the insoluble S04Pb. Lead once absorbed is eliminated very slowly, it becoming fixed by combination with the albuminoids, a form of combination which is ren- dered soluble by potassium iodide. The channels of elimination are by the perspiration, urine, and bile. In the analysis for mineral poisons (see p. 98), the major part of the Pb is precipitated as PbS in the treatment by H,S. The PbS remains upon the filter after extraction with ammonium sulphydrate ; it is treated with warm HC1, which decolorizes it by transforming the sulphide into chloride. The PbCl, thus formed is dissolved in hot H„0, from which it crystallizes on cooling. The solution still contains PbCl2 in sufficient quantity to respond to the tests for the metal. Although Pb is not a normal constituent of the body, the every-day methods by which it may be introduced into the economy, and the slow- ness of its elimination are such as to render the greatest caution neces- sary in drawing conclusions from the detection of Pb in the body after death. VI. BISMUTH GROUP. BISMUTH. Symbol — Bi—Atomic weight — 210—Molecular weight = 420 (?)—Sp. gr. = 9.677-9.935— at 247° (476°.6 F). This element is usually classed with Sb ; by some writers among the metals, by others in the phosphorus group. We are led to class Bi in our third class, and in a group alone, because : (1) while the so-called salts of Sb are not salts of the element, but of the radical (SbO)', antimonyl, Bi enters into saline combination, not only in the radical bismuthyl (BiO) but also as an element; (2) while the compounds of the elements of the N group in which those elements are quinquivalent are, as a rule, more stable than those in which they are trivalent, Bi is trivalent in all its known compounds except one, which is very unstable, in which it is quin- quivalent ; (3) the hydrates of the N group are strongly acid, and their corresponding salts are stable and well defined ; but those hydrates of Bi which are acid are but feebly so, and the bismuthates are unstable ; (4) no compound of Bi and H is known. Occurrence.—Occurs principally free, also as Bi,03 and BiS,. Properties.—Crystallizes in brilliant, metallic rhombohedra ; hard and brittle. It is only superficially oxidized in cold air. Heated to redness in air, it becomes coated with a yellow film of oxide. In H-,0 containing CO„ it forms a crystalline subcarbonate. It combines directly with Cl, Br, and I. It dissolves in hot S04H3 as sulphate, and in NO, 11 as nitrate. It is usually contaminated with As, from which it is best purified by 292 MANUAL OF CHEMISTRY. heating to redness a mixture of powdered bismuth, potassium carbonate, soap, and charcoal, under a layer of charcoal. After an hour the mass is cooled ; the button is separated and fused until its surface begins to be coated with a yellowish-brown oxide. Compounds of Bismuth. Oxides.—Four oxides are known : Bi202; Bi203; Bi204; and Bi206. Bismuth Trioxide—Bismuthous oxide — Protoxide—BiaOs— 468 — i3 formed by heating Bi, or its nitrate, carbonate, or hydrate, it is a pale yellow, insoluble powder ; sp. gr. 8.2 ; fuses at a red heat; soluble in HC1, N03H and S04H2 and in fused potash. Hydrates.—Bismuth forms at least four hydrates. Bismuthous Hydrate—BiH303—261—is formed as a white precipitate when potash or ammonium hydrate is added to a cold solution of a Bi salt. When dried, it loses H20 and is converted into bismuthyl hydrate (BiO)HO. Bismuthic Acid—(BiO,)HO—259—is deposited as a red powder when Cl is passed through a boiling solution of potash, holding bismuthous hy- drate in suspension. Pyrobismuthic Acid—Bi207H4—536—is a dark brown powder, precipi- tated from solution of bismuth nitrate by potassium cyanide. Bismuth Trichloride — Bismuthous chloride — BiCl3 — 316.5 — is formed by heating Bi in Cl; by distilling a mixture of Bi and mercuric chloride ; or by distilling a solution of Bi in aqua regia. It is a fusible, volatile, deliquescent solid ; soluble in dilute HC1. On contact with H20 it is decomposed with formation of bismuthyl chloride (BiO)Cl, or pearl white. Salts of Bismuth. Bismuth Nitrate—(NOs)3 Bi + 5 Aq—396 + 90—obtained by dissolv- ing Bi in N03H. It crystallizes in large, colorless prisms ; at 150° (302° F.), or by contact with li30, it is converted into bismuthyl nitrate ; at 260° (500° F.) into Bi203. Salts of Bismuthyl. Bismuthyl Nitrate—Trisnitrate or subnitrate of bismuth—Flake white—Bismuthi subnitras (U. S.; Br.)—NO (BiO)—288—is formed by de- composing a solution of (NOa)3Bi with a large quantity of H,,0. It is a white, heavy, faintly acid powder; soluble to a slight extent in H.,0 when freshly precipitated, the solution depositing it again on standing. It is de- composed by pure H„0, but not by H„0 containing jJ-w ammonium nitrate. It usually contains 1 Aq, which it loses at 100° (212° F.). Bismuth subnitrate is very liable to contamination with As ; the method followed in the preparation of the pharmaceutical product rarely excluding As completely, sometimes very imperfectly. It is also frequently contam- inated with Pb. Bismuthyl Carbonate—Bismuthi subcarbonas (U. S.)—Bismuthi car- bonas (Br )—CO,(BiO)a—512—is a white or yellowish precipitate, formed ZIRCONIUM. 293 by alkaline carbonates in solution of (N03)3Bi. Heat decomposes it into C03 and Bi203. Liable to contain As. Analytical Characters. (1.) Water : white ppt., even in presence of tartaric acid, but not of N03H, HC1, or S04H2. (2.) Hydrogen sulphide : black ppt.; insoluble in dilute acids and in alkaline sulphides. (3.) Ammonium sulphydrate : black ppt.; insoluble in excess. (4.) Potash, soda, or ammonia : white ppt.; insoluble in excess, and in tartaric acid ; turns yellow when the liquid is boiled. (5.) Potassium ferrocyanide : yellowish ppt.; insoluble in HC1. (6.) Potassium ferricyanide : yellowish ppt.; soluble in HC1. (7.) Infusion of galls : orange ppt. (8.) Potassium iodide : brown ppt.; soluble in excess. (9.) Reacts with Reinsch’s test (q. v.), but gives no sublimate in the glass tube. Action on the Economy. Although the medicinal compounds of bismuth probably are poisonous, if taken in sufficient quantity, the ill effects ascribed to them are in most, if not all cases, referable to contamination with arsenic. Symptoms of arsenical poisoning have not only been frequently observed when the subnitrate has been taken internally, but also when it has been used as a cosmetic. When preparations of bismuth are administered, the alvine discharges contain bismuth sulphide as a dark brown powder. VII. TIN GROUP. Titanium. Zirconium. Tin. Ti and Sn are bivalent in one series of compounds, SnCl.,, and quadri- valent in another, SnCl4. Zr, so far as known, is always quadrivalent. Each of these elements forms an acid (or salts corresponding to one) of the composition M03H2, and a series of oxysalts of the composition (N03)4 MiT. TITANIUM. Symbol = Ti—Atomic weight = 48—sp. gr. = 5.3. Occurs in clays and iron ores and as Ti02 in several minerals. Titanic anhydride, Ti02, is a white, in- soluble, infusible powder, used in the manufacture of artificial teeth ; dissolves in fused KHO as potassium titanate. Titanium combines readily with N, which it absorbs from air when heated. When NII3 is passed over red-hot Ti02, it is decomposed with formation of the violet nitride, TiN2. Another compound of Ti and N forms hard, copper-colored, cubical crystals. ZIRCONIUM. Occurs in zircon and hyacinth. Its oxide, zirconia, Zr02, is a white powder, insoluble in KTIO. Being infusible and not altered by exposure to air; it is used in pencils to replace lime in the calcium light. Symbol = Zr—Atomic weight = 89.6—up. gr. = 4.16. 294 MANUAL OF CHEMISTRY. TIN. Symbol = Sn (STANNUM) — Atomic weight = 117.7 —Molecular weight = 235.4 (?)— sp. gr. = 7.285-7.293—Fuses at 228° (442°.4 F.). Occurrence.—As tinstone (Sn02) and in stream tin. Preparation.—The commercial metal is prepared by roasting the ore, extracting with H20, reducing the residue by heating with charcoal, and refining. Pure tin is obtained by dissolving the metal in IICl ; filtering ; evapo- rating ; dissolving the residue in H20 ; decomposing with ammonium car- bonate ; and reducing the oxide with charcoal. Properties.—A soft, malleable, bluish-white metal; but slightly tena- cious ; emits a peculiar sound, the tin-cry, when bent. A good conductor of heat and electricity. Air affects it but little, except when it is heated ; more rapidly if Sn be alloyed with Pb. It oxidizes slowly in H„0, more rapidly in the presence of sodium chloride. Its presence with Pb accele- rates the action of H„0 upon the latter. It dissolves in HC1 as SnCl2. In presence of a small quantity of H..O, NO,H converts it into metastannic acid. Alkaline solutions dissolve it as metastannates. It combines directly with Cl, Br, I, S, P, and As. Tin plates are thin sheets of Fe, coated with Sn. Tin foil consists of thin laminae of Sn, frequently alloyed with Pb. Copper and iron vessels are tinned, after brightening, by contact with molten Sn. Pewter, bronze, bell metal, gun metal, britannia metal, speculum metal, type metal, solder, and fusible metal contain Sn. Compounds of Tin. Oxides.— Stannous Oxide—Protoxide—SnO — 133.7 — obtained by beating the hydrate or oxalate without contact of air. It is a white, amor- phous powder, soluble in acids and in hot concentrated solution of potash. It absorbs O readily. Stannic Oxide—Binoxide of tin—Sn02—149.7—occurs native as tin- stone or cassiterite, and is formed when Sn or SnO is heated in air. Hydrates.—Stannous Hydrate—SnH202—151.7—is a white precipitate formed by alkaline hydrates and carbonates in solutions of SnCl2. Stannic Acid—Sn03H2—167.7—is formed by the action of alkaline hy- drates on solutions of SnCl4. It dissolves in solutions of the alkaline hy- drates, forming stannates. Metastannic Acid—SnrOnH2—766.5—is a white, insoluble powder, formed by acting on Sn with NO.H. Chlorides. —Stannous Chloride—Protochloride— Tin crystals—SnCl2 + 2 Aq —188.7 + 36—is obtained by dissolving Sn in IIC1. It crystallizes in colorless prisms ; soluble in a small quantity of H20 ; decomposed by a large quantity, unless in the presence of free HC1, with formation of an oxychloride. Loses its Aq at 100° (212° F.). In air it is transformed into stannic chloride and oxychloride. Oxidizing and chlorinating agents con- vert it into SnCl4. It is a strong reducing agent. Stannic Chloride—Bichloride—Liquid of Libavius—SnCl4—259.7—by acting on Sn or SnCl2 with Cl, or by heating Sn in aqua regia. It is a fum- ing, yellowish liquid ; sp. gr. 2.28 ; boils at 120° (248° F.). PLATINUM. 295 Analytical Characters. Stannous.—(1.) Potash or soda: white ppt.; soluble in excess; the solution deposits Sn when boiled. (2.) Ammonium hydrate : white ppt.; insoluble in excess ; turns olive- brown when the liquid is boiled. (3.) Hydrogen sulphide: dark brown ppt. ; soluble in KHO, alkaline sulphides, and hot H20. (4.) Mercuric chloride : white ppt. ; turning gray and black. (5.) Auric chloride : purple or brown ppt., in presence of small quan- tity of N03H. (6.) Zinc : deposit of Sn. Stannic.—(1.) Potash or ammonia : white ppt. ; soluble in excess. (2.) Hydrogen sulphide : yellow ppt.; soluble in alkalies, alkaline sul- phides, and hot HC1. (3.) Sodium hyposulphite : yellow ppt. when heated. VIH. PLATINUM GROUP. Palladium. Platinum. IX. RHODIUM GROUP. Rhodium. Ruthenium. Iridium. The elements of these two groups, together with osmium, are usually classed as “metals of the platinum ores.” They all form hydrates (or salts representing them) having acid properties. Osmium has been re- moved because the relations existing between its compounds and those of molybdenum and tungsten are much closer than those which they ex- hibit to the compounds of these groups. The separation of the remaining platinum metals into two groups is based upon resemblances in the com- position of their compounds, as shown in the following table : PdCl2. .PtCl2.. PdCl4. .PtCl4.. Chlorides. RhCl2 . .RuCl, .. ? .. . .RuC14 . .IrCl4 .. Rh2Cl6.. Ru2C1# .. Ir2Cla.. PdO ..PtO .... Pd02. .PtOa Oxides. RhO ..RuO ..IrO Rh203. .Ru203. .Ir203 Rh02 . .Ru02 . .Ir02 Rh03 ..Ru03 ..Ir03 . .Ru04 .. PLATINUM. Symbol = Pt—Atomic weiqht = 194.4—Molecular weiqht — 388.8 (?) —sp. gr. = 21.1-21.5. Occurrence.—Free and alloyed with Os, Ir, Pd, Rh, Ru, Fe, Pb, Au, Ag, and Cu. Properties.—The compact metal has a silvery lustre ; softens at a white heat; may be welded ; fuses with difficulty ; highly malleable, ductile and tenacious. Spongy platinum is a grayish, porous mass, formed by 296 MANUAL OF CHEMISTRY. heating the double chloride of Pt and NH4. Platinum black is a black powder, formed by dissolving Pt Cl3 in solution of potash and heating with alcohol. Both platinum black and platinum sponge are capable of condens- ing large quantities of gas, and act as indirect oxidants. Platinum is not oxidized by air or O ; it combines directly with Cl, P, As, Si, S, and C ; is not attacked by acids, except aqua regia, in which it dissolves as PtCl4. It forms fusible alloys when heated with metals or reducible metallic oxides. It is attacked by mixtures liberating Cl, and by contact with heated phosphates, silicates, hydrates, nitrates, or carbonates of the alkaline metals. Platinic Chloride—Tetrachloride or perchloride of platinum—PtCl4— 336.4—is obtained by dissolving Pt in aqua regia, and evaporating. It crystallizes in very soluble, deliquescent, yellow needles. Its solution is used as a test for compounds of NH4 and K. PALLADIUM.—Symbol — Pd—Atomic weight — 105.7—sp. gr. = 11.5. A white metal resembling Pt in appearance and in chemical characters; but harder, lighter, more fusible, more readily oxidizable, and soluble in N03H as (N03)3Pd. It possesses in a higher degree than any other element the power of occluding, or condensing within its pores, hydrogen; of which it absorbs 040 times its volume at 100° (212° F.). RHODIUM.—Symbol = Rh—Atomic weight = 104.1—sp. gr. = 11.4. A hard, malleable, white metal, insoluble in aqua regia, which occurs in Pt ores, and alloyed with Au. Its compounds are for the most part red in the solid form or in solution, whence its name, from poSov, a rose. RUTHENIUM—Symbol = Ru—Atomic weight = 104.2 sp. gr. — 11.4. A hard, brittle, very difficultly fusible metal, not dissolved by aqua regia, occurring in Pt ores. IRIDIUM— Symbol = Ir—Atomic weight = 192.7—sp. gr. — 22.3. A hard, brittle metal, occurring alloyed with osmium ; not attacked by aqua regia. Platinum alloyed with 15-20 per cent. Ir is less fusible, more rigid, harder, denser and less readily attacked chemically than pure Pt. ANALYTICAL CHARACTERS. 297 CLASS IV.—BASYLOUS ELEMENTS. Elements whose Oxides Unite with Water to form Bases ; never to form Acids. Which form Oxysalts. I. SODIUM GROUP. Alkaline Metals. Lithium—Sodium—Potassium. Rubidium—Cesium—Silver. Each of the elements of this group forms a single chloride, M'Cl, and one or more oxides, the most stable of which has the composition M'aO ; they are, therefor, univalent. Their hydrates, M HO, are more or less alkaline and have markedly basic characters. Silver resembles the other members of the group in chemical properties, although it does not in physical characters. LITHIUM. Symbol = Li—Atomic weight = 7—Molecular weight = 14 (?)—Sp. gr. = 0.589—Fuses at 180° (356° F.)—Discovered by Arfvedson in 1817— Name from Xidtios — stony. Occurrence.—Widely distributed in small quantity ; in many minerals and mineral waters ; in the ash of tobacco and other plants; in the milk and blood. Properties.—A silver-white, ductile, volatile metal; the lightest of the solid elements ;• burns in air with a crimson flame ; decomposes at ordinary temperatures, without igniting. Lithium Oxide—Li20—30—is a white solid, formed by burning Li in dry O. It dissolves slowly in H O to form lithium hydrate—LiHO. Lithium Chloride—LiCl—43.5—crystallizes in deliquescent, reg- ular octahedra ; very soluble in H20 and in alcohol. Lithium Bromide—Lithii bromidum (U. S.)—LiBr—87—is formed by decomposing lithium sulphate with potassium bromide ; or by satur- ating a solution of HBr with lithium carbonate. It crystallizes in very deliquescent, soluble needles. Lithium Carbonate—Lithii carbonas (U. S.; Br.)—C03Li2—74—is a white, sparingly soluble, alkaline, amorphous powder. With uric acid it forms lithium urate (q. v.). Analytical Characters. (1.) Ammonium carbonate : white ppt. in concentrated solutions; not in dilute solutions or in presence of ammoniacal salts. (2.) Sodium phosphate : white ppt. in neutral or alkaline solution ; soluble in acids and in solutions of ammoniacal salts. 298 MANUAL OF CHEMISTRY. (3.) It colors the Bunsen flame red ; and exhibits a spectrum of two lines—A = 6705 and 6102 (Fig. 14, No. 4). SODIUM. Symbol Na (NATRIUM) —Atomic weight = 23—Molecular weight, — 46 (?)—Sp. gr. = 0.972—Fuses at 95°.6 (204°. 1F.)—Discovered by Davy, 1807. Occurrence.—As chloride very abundantly and widely distributed ; also as carbonate, nitrate, sulphate, borate, etc. Preparation.—By heating a mixture of dry sodium carbonate, chalk, and charcoal to whiteness in iron retorts, connected with suitable condensers in which the distilled metal collects under a layer of coal naphtha. Properties.—A silver-white metal, rapidly tarnished and coated with a yellow film in air. Waxy at ordinary temperatures; volatile at a white heat. In air it is gradually oxidized from the surface, but may be kept in closed vessels without the protection of a layer of naphtha. It decomposes H20, sometimes explosively. Burns with a yellow flame. Combines di- rectly with Cl, Br, I, S, P, As, Pb, and Sn. Compounds of Sodium. Oxides.—Two oxides are known: Sodium monoxide—Na20—a grayish- wliite mass ; formed when Na is burnt in dry air, or by the action of Na on NaHO. Sodium dioxide—Na204—a white solid, formed when Na is heated in dry air to 200° (392° F.). Sodium Hydrate—Caustic soda—Soda (U. S.)—Soda caustica (Br.)— NaHO—40 —is formed : (1) when H20 is decomposed by Na ; (2) by de- composing sodic carbonate by calcium hydrate : C03Na2 -f- CaH202 = C03 Ca + 2NaHO (soda by lime); (3) in the same manner as in (2), using barium hydrate in place of lime (soda by baryta). It frequently contains con- siderable quantities of As. It is an opaque, white, fibrous, brittle solid ; fusible below redness ; sp. gr. 2.00 ; very soluble in H20, forming strongly alkaline and caustic solu- tions (isoda lye and liq. sodce). "When exposed to air, solid or in solution, it absorbs H20 and C02 and is converted into carbonate. Its solutions attack glass. Sodium Chloride—Common salt—Sea salt—Table salt—Sodii chloridum (VS., Br.)—NaCl—58.5—occurs very abundantly in nature, deposited in the solid form as roc/c salt ; in solution in all natural waters, especially in sea and mineral spring waters ; in suspension in the atmosphere ; and as a constituent of almost all animal and vegetable tissues and fluids. It is formed in an infinite variety of chemical reactions. It is obtained from rock salt, or from the waters of the sea or of saline springs; and is the source from which all the Na compounds are usually obtained, directly or indirectly. It crystallizes in anhydrous, white cubes or octahedra ; sp. gr. 2.078 ; fuses at a red heat, and crystallizes on cooling : sensibly volatile at a white heat; quite soluble in H20, the solubility varying but slightly with the COMPOUNDS OF SODIUM. 299 temperature. Dilute solutions yield pure ice on freezing. It is precipi- tated from concentrated solutions by HC1. It is insoluble in absolute alcohol; sparingly soluble in dilute spirit. It is decomposed by S04H2 with formation of HC1 and sodium sulphate : 2NaCl + S04H = 2HC1 4- S04Na2. Physiological.—Sodium chloride exists in every animal tissue and fluid, and is present in the latter, especially the blood, in tolerably con- stant proportion. It is introduced with the food, either as a constituent of the alimentary substances, or as a condiment. In the body it serves to aid the phenomena of osmosis and to maintain the solution of the albu- minoids. It is probable, also, that it is decomposed in the gastric mucous membrane with formation of free hydrochloric acid. It is discharged from the economy by all the channels of elimination, notably by the urine, when the supply by the food is maintained. If, however, the food contain no salt, it disappears from the urine before it is exhausted from the blood. The amount of Cl (mainly in the form of NaCl) voided by a normal male adult in 24 hours is about 10 grams (154 grains), corresponding to 16.5 grams (255 grains) of NaCl. When normal or excessive doses are taken, the amount eliminated by the urine is less than that taken in ; when small quantities are taken, the elimination is at first in excess of the supply. The hourly elimination increases up to the seventh hour, when it again diminishes. The amount of NaCl passed in the urine is less than the normal in acute, febrile diseases; in intermittent fever it is diminished during the paroxysms, but not during the intervals. In diabetes it is much increased, sometimes to 29 grams (448 grains) per diem. Quantitative determination of chlorides in urine.—The process is based upon the formation of the insoluble silver chloride, and upon the formation of the brown silver chromate in neutral liquids, in the absence of soluble chlorides. The solutions required are : (1) solution of silver nitrate of known strength, made by dissolving 29.075 grams of pure, fused silver nitrate (see p. 310) in a litre of water ; (2) a solution of neutral potassium chromate. To conduct the determination, 5-10 c.c. of the urine are placed in a platinum basin, 2 grams of sodium nitrate (free from chloride) are added ; the whole is evaporated to dryness over the water-batli, and the residue heated gradually until a colorless, fused mass remains. This, on cooling, is dissolved in H.20, the solution placed in a small beaker, treated with pure, dilute N03H to faintly acid reaction, and neutralized with calcium carbonate. Two or three drops of the chromate solution are added, and then the silver solution from a burette, during constant stirring of the liquid in the beaker, until a faint reddish tinge remains permanent. Each c.c. of the silver solution used represents 10 milligrams NaCl (or 6.065 milligrams Cl) in the amount of urine used. Example.—5 c.c. urine used ; 6 c.c. silver solution added ; 1,200 c.c. urine passed in 24 hours: . v ‘ r X- x 1,200 = 14.4 grams NaCl in 24 hours. ° If the urine contain iodides or bromides, they must be removed by acidulating the solution of the residue of incineration with S04H2, remov- ing the iodine or bromine by shaking with carbon disulphide, neutralizing the aqueous solution with calcium carbonate and proceeding as above. Sodium Bromide—Sodii bromidum (V. S.)—NaBr—103—is formed by dissolving Br in solution of NaHO to saturation; evaporating ; calcining 300 MANUAL OF CHEMISTRY. at dull redness ; redissolving ; filtering ; and crystallizing. It crystallizes in anhydrous cubes ; quite soluble in H20, soluble in alcohol. Sodium Iodide—Sodii iodidum (U. S.)—Nal—150—is prepared by heating together H20, Fe, and I in fine powder ; filtering ; adding an equivalent quantity of sodium sulphate and some slacked lime ; boiling ; decanting and evaporating. Crystallizes in anhydrous cubes ; very sol- uble in H20 ; soluble in alcohol. Salts of Sodium. Sodium Nitrate—Cubic or Chili saltpetre—Sodii nitras (U S.)—Sodce nitras (Br.)—N03Na—85—occurs in natural deposits in Chili and Peru. It crystallizes in anhydrous, deliquescent rhombohedra ; cooling and some- what bitter in taste ; fuses at 310° (590° F.); very soluble in Ii20. Heated with S04H2 it is decomposed, yielding N03H and hydrosodic sulphate : S04H2+ N03Na = S04HNa + N03H. Sulphates—Hydrosodic Sulphate—Acid sodium sulphate—Bisulphate —S04HNa—120—crystallizes in long, four-sided prisms ; is unstable and decomposed by air, H20 or alcohol, into S04H„ and S04Na2. Heated to dull redness it is converted into sodium pyrosulphate, S207Na2, correspond- ing to Nordhausen sulphuric acid. Sodic Sulphate—Neutral sodium sulphate—Glauber’s salt—Sodii sulphas (U. S.)—Sodce sulphas (Br.)—S04Na2 + n Aq—142 -f n 18—occurs in nature in solid deposits and in solution in natural waters. It is obtained principally as a step in the manufacture of the carbonate by the action of S04H2 on NaCl. It crystallizes with 7 Aq, from saturated or supersaturated solutions at 5° (41° F.) ; or, more usually, with 10 Aq. As usually met with it is in large, colorless, oblique rhombic prisms with 10 Aq ; which effloresce in air and gradually lose all their Aq. It fuses at 33° (91°.4 F.) in its Aq, which it gradually loses. If fused at 33° (91°.4 F.) and allowed to cool, it remains liquid in supersaturated solution, from which it is deposited, the entire mass becoming solid, on contact with a small particle of solid mat- ter. It dissolves in HC1 with considerable diminution of temperature. Physiological.—The neutral sulphates of Na and K seem to exist in small quantity in all animal tissues and fluids, with the exception of milk, bile, and gastric juice ; certainly in the blood and urine. They are partially introduced with the food, and partly formed as a result of the metamor- phosis of those constituents of the tissues which contain S in organic combination. The principal elimination of the sulphates is by the urine. All the sulphuric acid in the urine is not in simple combination with the alkaline metals; a considerable amount exists in the form of the alkaline salts of conjugate, monobasic ether acids, which on decomposition yield an aro- matic organic compound. The amount of S04H2 discharged by the urine in 24 hours, in the form of alkaline sulphates, is from 2.5 to 3.5 grams (38.5-54 grains) ; that eliminated in the salts of conjugate acids, 0.617 to 0.094 gram (9.5-1.5 grains). Sodium Sulphite—Sodii sidphis (U. S.)—SO..Na2 + 7 Aq—126 + 126—is formed by passing S02 over crystallized C03Na2. It crystallizes in efflorescent, oblique prisms; quite soluble in H20, forming an alkaline solution. It acts as a reducing agent. SALTS OF SODIUM. 301 Sodium Hyposulphite—Sodii hyposulphis (U. S.)— S„0.,Na„ -f- 5 Aq —158 + 90—is obtained by dissolving S in hot concentrated solution of S03Na2, and crystallizing. It forms large, colorless, efflorescent prisms; fuses at 45° (113° F.); very soluble in H,,0 ; insoluble in alcohol. Its solutions precipitate alu- mina from solutions of A1 salts, without precipitating Fe or Mn ; they dis- solve many compounds insoluble in H20 ; cuprous hydrate, iodides of Pb, Ag and Hg, sulphates of Ca and Pb. It acts as a disinfectant and anti- septic. Silicates.—Quite a number of silicates of Na are known. If silica and C03Na2 be fused together, the residue extracted with H.,0, and the solution evaporated, a transparent, glass-like mass, soluble in warm water, remains; this is soluble glass or water glass. Exposed to air in contact with stone, it becomes insoluble, and forms an impermeable coating. Phosphates.—Trisodic Phosphate—Basic sodium phosphate—POtNa.t + 12 Aq—164 + 216—is obtained by adding NaHO to disodic phosphate solution and crystallizing. It forms six-sided prisms ; quite soluble in H.,0. Its solution is alkaline, and, on exposure to air, absorbs C02 with formation of P04HNa2 and C03Na2. Disodic Phosphate —Hydro-disodic phosphate—Neutral sodium phosphate —Phosphate of soda—Sodii phosphas (U. S.)—Sodce phosphas (Br.)—P04 HNa2 + 12 Aq—142 + 216—is obtained by converting tricalcic phosphate into monocalcic phosphate and decomposing that salt with sodium carbo- nate : (P04H,)2Ca -(- 2C03Na2 = C03Ca + H,0 + C02 + 2P04HNa2. Below 30° (86° F.) it crystallizes in oblique rhombic prisms with 12 Aq ; at 33° (91°.4 F.) it crystallizes with 7 Aq. The salt with 12 Aq ef- floresces in air and parts with 5 Aq ; and is very soluble in H.,0. The salt with 7 Aq is not efflorescent and less soluble in H20. Its solutions are faintly alkaline. Monosodic Phosphate—Acid sodium phosphate—P04H2Na + Aq—120 + 18—crystallizes in rhombic prisms ; forming acid solutions. At 100° (212° F.) it loses Aq ; at 200° (392° F.) it is converted into acid pyrophos- phate, P207Na2H2 ; and at 204° (399°.2 F.) into the metaphosphate, P03Na. Physiological.—All the sodium phosphates exist, accompanied by the corresponding K salts, in the animal economy. The disodic and dipotas- sic phosphates are the most abundant, and of these two the former. They exist in every tissue and fluid of the body, and are more abundant in the fluids of the carnivora than in those of the herbivora. In the blood, in which the Na salt predominates in the plasma, and the K salt in the cor- puscles, they serve to maintain an alkaline reaction. With strictly vege- table diet the proportion of phosphates in the blood diminishes, and that of the carbonates (the predominating salts in the blood of the herbivora) increases. The monosodic and monopotassie phosphates exist in the urine, the former predominating, and to their presence the acid reaction of that fluid is largely due. They are produced by decomposition of the neutral salts by uric acid. The urine of the herbivora, whose blood is poor in phosphates, is alkaline in reaction. The greater part of the phosphates in the body are introduced with the food. A portion is formed in the economy by the oxidation of plios- phorized organic substances, the lecithins. Disodic Tetraborate—Sodium pyroborate—Borate of sodium—Borax —Tincal—Sodii boras (U. S.)—Borax (Br.)— + 10 Aq—202 + 180 —is prepared by boiling boracic acid with C03Na2 and crystallizing. It 302 MANUAL OF CHEMISTRY. crystallizes in hexagonal prisms with 10 Aq; permanent in moist air, but efflorescent in dry air ; or in regular octahedra with 5 Aq, permanent in dry air. Either form, when heated, fuses in its Aq, swells considerably ; at a red heat becomes anhydrous ; and, on cooling, leaves a transparent, glass-like mass. When fused it is capable of dissolving many metallic oxides, forming variously colored masses, hence its use as a flux and in blow-pipe analysis. Sodium Hypochlorite—ClONa—74.5—only known in solution— Liq. sodce chloratce (U. S.; Br.) or Laharraques solution—obtained by de- composing a solution of chloride of lime by C03Na2. It is a valuable source of Cl, and is used as a bleaching and disinfecting agent. Sodium Manganate—Mn04Na2 + 10 Aq—164 + 180—faintly col- ored crystals, forming a green solution with HaO—Condys green disin- fectant. Sodium Permanganate—Mn,20#NaJ—282—prepared in the same way as the K salt (q. v.), which it resembles in its properties. It enters into the composition of Condys fluid, and of “chlorozone,” which contains Mn208Na2 and ClONa. Sodium Acetate—Sodii acetas(U. S.)—Sodce acetas (Br.)—C2Hs02Na + 3Aq—82 + 54—crystallizes in large, colorless prisms ; acid and bitter in taste ; quite soluble in H20 ; soluble in alcohol; loses its Aq in dry air, and absorbs it again from moist air. Heated with soda lime, it yields marsh gas. The anhydrous salt, heated with S04H2, yields glacial acetic acid. Carbonates.—Three are known: C03Na2; CO.HNa; and (C03). H2 Na4. Some Carbonate.—Neutral carbonate—Soda—Sal soda—Washing soda— Soda crystals—Sodii carbonas (U. S.)—Sodce carbonas (Br.)—CO3Na24-10 Aq- -106 +180—industrially the most important of the Na compounds, is manufactured by Leblanc’s or Solvay’s processes ; or from cryolite, a na- tive fluoride of Na and Al. Leblanc’s process, in its present form, consists of three distinct pro- cesses : (1.) The conversion of NaCl into the sulphate by decomposition by S04H2. (2.) The conversion of the sulphate into carbonate by heating a mixture of the sulphate with calcium carbonate and charcoal. The pro- duct of this reaction, known as black ball soda, is a mixture of sodium carbonate with charcoal and calcium sulphide and oxide. (3.) The puri- fication of the product obtained in (2). The ball black is broken up, dis- integrated by steam, and lixiviated. The solution on evaporation yields the soda salt or soda of commerce. Of late years Leblanc’s process has been in great part replaced by Solvay’s method, or ammonia process, which is more economical and yields a purer product. In this process sodium chloride and ammonium bicar- bonate react upon each other, with production of the sparingly soluble sodium bicarbonate and the very soluble ammonium chloride. The sodium bicarbonate is then simply collected, dried, and heated, when it is decom- posed into C03Na2, H20, and CO„. The anhydrous carbonate, Sodii carbonas exsiccatus (U. S.), CO.Na„, is formed as a white powder by calcining the crystals. It fuses at dull red- ness and gives off a little C02. It combines with and dissolves in H O with elevation of temperature. The crystalline sodium carbonate, CO,Na„ + 10 Aq, forms large rhom- bic crystals, which effloresce rapidly in dry air ; fuse in their Aq at 34° (93°.2 F.); are soluble in H„0, most abundantly at 38° (100°.4 F.). The solutions are alkaline in reaction. POTASSIUM. 303 Hydrosodic Carbonate—Monosodic carbonate—Bicarbonate of soda— Acid carbonate of soda—Vichy salt—Sodii bicarbonas—(U. S.)—Sodce bi- carbonas (Br.)—C03NaH—84—exists in solution in many mineral waters. It is obtained by the action of C03 upon the disodic salt in the presence of H30. It crystallizes in rectangular prisms, anhydrous and permanent in dry air ; in damp air it gives off C02 and is converted into the sesquicarbonate, (C03)3Na4H. When heated, it gives off C02 and H30, and leaves the disodic carbonate ; quite soluble in water ; above 70° (158° F.) the solu- tion gives off C03. The solutions are alkaline. Physiological.—The fact that the carbonates of Na and K are almost invariably found in the ash of animal tissues and fluids, is no evidence of their existence there in life, as the carbonates are produced by the incinera- tion of the Na and K salts of organic acids. There is, however, excellent indirect proof of the existence of the alkaline carbonates in the blood, especially of the herbivora, in the urine of the herbivora at all times, and in that of the carnivora and omnivora when food rich in the salts of the organic acids, with alkaline metals, is taken. The carbonates in the blood are both the mono- and disodic and potassic ; and the carbonic acid in the plasma is held partially in simple solution, and partly in combination in the monometallic carbonates. Analytical Characters. (1.) Hydrofluosilicic acid : gelatinous ppt., if not too dilute. (2.) Potassium pyroantimonate : in neutral solution and in absence of metals, other than K and Li : a white flocculent ppt. ; becoming crystal- line on standing. (3.) Periodic acid in excess : white ppt., in not too dilute solutions. (4.) Colors the Bunsen flame yellow, and shows a brilliant double line at X = 5895 and 5889 (Fig. 14, No. 2). POTASSIUM. Symbol = K (KALIUM) —Atomic weight = 39—Molecular weight — 78 (?)—Sp. gr. = 0.865—Fuses at 62°.5 (144°.5 F.)—Discovered by Davy, 1807—Names from pot ash, and Kali = ashes (Arabic). It is prepared by a process similar to that followed in obtaining Na ; is a silver-white metal; brittle at 0° (32° F.) ; waxy at 15° (59° F.) ; fuses at 62°.5 (144°.5 F.) ; distils in green vapors at a red heat, condensing in cubic crystals. It is the only metal which oxidizes at low temperatures in dry air, in which it is rapidly coated with a white layer of oxide or hydrate, and fre- quently ignites, burning with a violet flame ; it must, therefor, be kept under naphtha. It decomposes H O or ice with great energy, the heat of the reaction igniting the liberated H. It combines with Cl with incan- descence, and also unites directly with S, P, As, Sb, and Sn. Heated in C03 it is oxidized and liberates C. 304 MANUAL OF CHEMISTRY. Compounds of Potassium. Oxides.—Three are known : K20 ; K202 ; and K204. Potassium Hydrate—Potash — Potassa — Comvion caustic — Potassa (U. S.)—Potassa caustica (Br.)—KHO—56—is obtained by a process simi- lar to that used in manufacturing NaHO. It is purified by solution in al- cohol, evaporation and fusion in a silver basin and casting in silver moulds—potash by alcohol; it is then free from KC1 and S04K2, but con- tains small quantities of C03K and frequently As. It is usually met with in cylindrical sticks, hard, white, opaque, and brittle. The KHO by alcohol has a bluish tinge and a smoother surface than the common ; sp. gr. 2.1 ; fuses at dull redness ; is freely soluble in H20, forming a strongly alkaline and caustic liquid ; less soluble in alcohol. In air, solid or in solution, it absorbs H20 and C02, and is converted into C03K2. Its solutions dissolve Cl, Br, I, S, and P. It decomposes the am- moniacal salts with liberation of NH3 ; and the salts of many of the metals, with formation of a K salt and a metallic hydrate. It dissolves the albuminoids ; and, when heated, decomposes them with formation of leu- cin, tyrosin, etc. It oxidizes the carbohydrates with formation of potas- sium oxalate and carbonate. Sulphides.—Five are known: K2S, K2S2, K2Ss, K2S4, and K2S6; also a sulphydrate: KHS. Potassium Monosulphide—K2S—110—is formed by the action of IvHO on KHS. Potassium Disulphide—K2S2—142—is an orange-colored solid, formed by exposing an alcoholic solution of KHS to the air. Potassium Tkisulphide—K2S3—174—a brownish-yellow mass, obtained by fusing together C03K2 and S in the proportion : 4C03K2 + 10S = S04 Iv2 + 3K„S3 + 4C02. Potassium Pentasulphide—K„S5—238—is formed, as a brown mass, when C0.K and S are fused together in the proportion : 4CO K + 16S = 4C02 + 3K.,Ss + S04K2. I Aver of sulphur—hepar sulphuris—potassi sulphuratum (U S.; Br.)—is a mixture of K2S3 and K2S5. Potassium Sulphydrate—KHS—72—is formed by saturating a solution of KHO with H2S. Potassium Chloride—Sal digestivum Sylvii—KC1—74.5—exists in nature, either pure or mixed with other chlorides ; principally as carnallite, KC1, MgCl2 + 6 Aq. It crystallizes in anhydrous, permanent cubes, sol- uble in H20. Potassium Bromide—Potassii bromidum (U. S.; Br.)—KBr—119— is formed either by decomposing ferrous bromide by C03K2, or by dis- solving Br in solution of KHO. In the latter case the bromate formed is converted into KBr by calcining the product. It crystallizes in anhydrous cubes or tables ; has a sharp, salty taste ; very soluble in H20, sparingly so in alcohol. It is decomposed by Cl with liberation of Br. Potassium Iodide—Potassii iodidum (U. S.; Br.)—KI—166—is ob- tained by saturating KHO solution with I, evaporating, and calcining the resulting mixture of iodide and iodate with charcoal. It frequently con- tains iodate and carbonate. It crystallizes in cubes, transparent if pure; permanent in air; anhydrous ; soluble in H20 and in alcohol. It is de- composed by Cl, NOaH, and N02H, with liberation of I. It combines with other iodides to form double iodides. 305 SALTS OF POTASSIUM. Salts of Potassium. Potassium Nitrate—Nitre—Saltpetre—Potassii nitras (U. S.)—Potassce nitras (Br.)—NO;iK—101—occurs in nature and is produced artificially as a result of the decomposition of nitrogenized organic substances. It. is usually obtained by decomposing native N03Na by boiling solution of C03 Kaor KC1. It crystallizes in six-sided, rhombic prisms, grooved upon the surface ; soluble in H.,0 with depression of temperature ; more soluble in H O con- taining NaCl; very sparingly soluble in alcohol; fuses at 350° (662° F.) without decomposition ; gives off O and is converted into nitrite below redness ; more strongly heated, it is decomposed into N, O, and a mixture of K oxides. It is a valuable oxidant at high temperatures ; heated with charcoal it deflagrates. Gunpowder is an intimate mixture of NOK with S and C, in such pro- portion that the N03K yields all the O required for the combustion of the S and C. Potassium Chlorate—Potassii chloras (U. S.)—Potassce chloras (Br.)— ClOK—122.5—is prepared : (1) by passing Cl through a solution of KHO ; (2) by passing Cl over a mixture of milk of lime and KC1, heated to 60° (140" F.). It crystallizes in transparent, anhydrous plates ; soluble in H,0 ; sparingly soluble in weak alcohol. It fuses at 400° (752° F.). If further heated it is decomposed into KC1 and perchlorate, and at a still higher temperature the perchlorate is decom- posed into KC1 and O : 2C103K = CIO/K + KC1 + 02 and C104K = KC1 + 20„. It is a valuable source of O, and a more active oxidant than NO IL When mixed with readily oxidizable substances, C, S, P, sugar, tannin, resins, etc., the mixtures explode when subjected to shock. With strong SO(H, it gives off Cl.,0,, an explosive yellow gas. It is decomposed by NOaH with formation of N03K, C104K, and liberation of Cl and O. Heated with HC1 it gives off a mixture of Cl and C1204, the latter acting as an ener- getic oxidant in solutions in which it is generated. Potassium Hypochlorite—ClOK—90.5—is formed in solution by imperfect saturation of a cooled solution of KHO with hypochlorous acid. An impure solution is used in bleaching : Javelle water. Sulphates.—Potassic Sulphate—Dipotassic sulphate—Potassii sulphas (U S.)—Potassce sulphas (Br.)—SOK2 —174—occurs native ; in the ash of many plants ; and in solution in mineral waters. It crystallizes in right rhombic prisms ; hard ; permanent in air ; salt and bitter in taste ; soluble in H20. Hydropotassic Sulphate—Monopotassic sulphate—Acid sulphate—S04 KH—136—is formed as a by-product in the manufacture of NOsH. When heated it loses HX1, and is converted into the pyrosulphate, S207K2, which, at a higher temperature, is decomposed into S04K2 and S02. Potassic Sulphite—Dipotassic sulphite—Potassii sulphis (U. S.)— S03K2—158—is formed by saturating solution of C03K2 with S02, and evaporating over S04H2. It crystallizes in oblique rhombohedra ; soluble in H,0. Its solution absorbs O from air, with formation of S04K . Potassium Dichromate—Bichromate of potash—Potassii bichromas (U. S.)—Potassce bichromas (Br.)—Cr O.K,—294.8—is formed by heating a mixture of chrome iron ore with NOaK, or C03K2 in air ; extracting with HO ; neutralizing with dilute SO,H, ; and evaporating. It forms large, reddish-orange colored prismatic crystals ; soluble in H20; fuses below 306 MANUAL OF CHEMISTRY. redness, and at a higher temperature is decomposed into O, potassium chromate, and sesquioxide of chromium. Heated with HC1, it gives off Cl. Potassium Permanganate—Potassii permanganas (U. S.)—Potasses permanganas (Br.)—Mn2OsK1—314—is obtained by fusing a mixture of manganese dioxide, KHO, and C103K, and evaporating the solution to crys- tallization ; Mn04K2 and KC1 are first formed ; on boiling with H20 the manganate is decomposed into Mn2OeK2 and KHO and MnO.,. It crystallizes in dark prisms, almost black, with greenish reflections, which yield a red powder when broken. Soluble in H20, communicating to it a red color, even in very dilute solution. It is a most valuable oxidiz- ing agent. With organic matter its solution is turned to green by the for- mation of the manganate, or deposits the brown sesquioxide of manganese, according to the nature of the organic substance ; in some instances the reaction takes place best in the cold, in others under the influence of heat; in some better in acid solutions, in others in alkaline solutions. Mineral reducing agents act more rapidly. Its oxidizing powers render its solu- tions valuable as disinfectants. Potassium Acetate—Potassii acetas (U. S.)—Potasses acetas (Br.)— C3H302K—110—exists in the sap of plants ; and it is by its calcination that the major part of the carbonate of wood ashes is formed. It is pre- pared by neutralizing acetic acid with C03K2 or C03KH. It forms crystalline needles, deliquescent, and very soluble in H20; less soluble in alcohol. Its solutions are faintly alkaline. Carbonates—Potassic Caebonate—Salt of tartar—Pearl ash—Potassii carbonas (U. S.)—Potassoe carbonas (Br.)—C03K2—138—exists in mineral waters and in the animal economy. It is prepared industrially in an impure form, known as p>otash or pearlash, from wood ashes, from the molasses of beet-sugar, and from the native Stassfurth chloride. It is obtained pure by decomposing the monopotassic salt, purified by several recrystallizations, by heat or by calcining a potassium salt of an organic acid. Thus cream of tartar, mixed with nitre and heated to redness, yields a black mixture of C and C03K„, called black flux ; on extracting which with H20, a pure carbonate, known as salt of tartar, is dissolved. Anhydrous, it is a white, granular, deliquescent, very soluble powder. At low temperatures it crystallizes with 2 Aq. Its solution is alkaline. Hydkopotassic Carbonate—Monopotassic carbonate—Bicarbonate—Potassii bicarbonas (U. S.)—Potasses bicarbonas (Br.)—CO.HK—100—is obtained by dissolving C03K2 in H O and saturating the solution with C02. It crys- tallizes in oblique rhombic prisms, much less soluble than the carbonate. In solution it is gradually converted into the dipotassic salt when heated, when brought into a vacuum, or when treated with an inert gas. The solutions are alkaline in reaction and in taste, but are not caustic. The substance used in baking, under the name salcsratus, is this or the corresponding Na salt. Its extensive use in some parts of the country is undoubtedly in great measure the cause of the prevalence of dyspepsia. When used alone in baking it “raises” the bread by decomposition into carbon dioxide and dipotassic (or disodic) carbonate, the latter producing disturbances of digestion by its strong alkaline reaction. Hydropotassic Oxalate—Monopotassic oxalate—Binoxalate of potash— C„04HK—128—forms transparent, soluble, acid needles. It occurs, along with the quadroxalate, C204HK, C204H2 -f 2 Aq, in salt of lemon or salt of sorrel, used in straw bleaching and for the removal of ink-stains, etc. It SALTS OF POTASSIUM. 307 closely resembles Epsom salt in appearance, and has been fatally mistaken for it. Tartrates.—Potassic Taeteate—Dipotassic tartrate—Soluble tartar— Neutral tartrate of potash—Potassii tartras (U. S.)—Potassce tartras (Br.)— C4H406K2—226 —is prepared by neutralizing the hydropotassic salt with potassium carbonate. It forms a white, crystalline powder, very soluble in H20, the solution being dextrogyrous, [a]D = + 28°.48 ; soluble in alcohol. Acids, even acetic, decompose its solution with precipitation of the monopotassic salt. Hydeopotassic Taeteate—Monopotassic tartrate—Cream of tartar—Po- tassii bitartras (U. S.)—Potassce bitartras (Br.)—C4H4OfiHK—188.—Dur- ing the fermentation of grape-juice, as the proportion of alcohol increases, crystalline crusts collect in the cask. These constitute the crude tartar or argol of commerce, which is composed, in great part, of monopotassic tar- trate. The crude product is purified by repeated crystallization from boiling H.,0 ; digesting the purified tartar with HC1 at 20° (68° F.) ; washing with cold H20, and crystallizing from hot H.,0. It crystallizes in hard, opaque (translucent when pure), rhombic prisms, which have an acidulous taste, and are very sparingly soluble in H20, still less soluble in alcohol. Its solution is acid, and dissolves many metallic oxides with formation of double tartrates. When boiled with antimony trioxide, it forms tartar emetic. It is used in the household, combined with monosodic carbonate, in baking, the two substances reacting upon each other to form Rochelle salt, with liberation of carbon dioxide. Baking-powdees are now largely used as substitutes for yeast in the manufacture of bread. Their action is based upon the decomposition of C03HNa by some salt having an acid reaction, or by a weak acid. In ad- dition to the bicarbonate and flour, or corn starch (added to render the bulk convenient to handle and to diminish the rapidity of the reaction), they contain cream of tartar, tartaric acid, alum, hydrochloric acid, or acid phosphates. Sometimes ammonium sesquicarbonate is used, in whole or in part, in place of sodium carbonate. The reactions by which the C02 is liberated are: 1. C4H4OfHK + C03NaH = C4H406NaK + H20 + C02. Hydropotassic Hydrosodic tartrate. carbonate. Sodium potassium tartrate. Water. Carbon. dioxide. 2. C4H406H2 + 2C03NaH = C4H406Naa + 2H20 + 2C0a Tartaric acid. Hydrosodic carbonate. Disodic tartrate. Water. Carbon dioxide. 3. (S04)3A12,S04K2 + 6COsNaH = S04K2 + 3S04Na3 + Al2Hfi0e-i-6C0a. Aluminium potassium alum. Hydrosodic carbonate. Potassic sulphate. Sodic sulphate. Aluminium hydrate. Carbon dioxide. 4. (S04)3A12,S04(NH4)2 + 6C03NaH = S04(NH4)a + 3S04Na2 + Aluminium ammonium alum. Hydrosodic carbonate. Ammonic sulphate. Sodic sulphate. Al2Hr;06 + 6C02 Aluminium hydrate. Carbon dioxide. 5. (S04)3Ala 4- 6C0.,NaH = 3S04Naa + A1,H 0, + 6C0a. Aluminium sulphate. Hydrosodic carbonate. Sodic sulphate. Aluminium hydrate. Carbon dioxide. 308 MANUAL OF CHEMISTRY. 6. HC1 + C03NaH = NaCl + H20 + CO,2. Hydrochloric acid. Hydrosodic carbonate. Sodium chloride. Water. Carbon dioxide. 7. P04NaH2 + COsNaH = P04Na2H 4- H20 + C02. Monoaodic phosphate. Hydrosodic carbonate. Disodic phosphate. Water. Carbon dioxide. 8. 2(S04)3A12 + 3[2(CO, [NHJa)CO„] + 6H20 = 6S04(NH4)a + Aluminium sulphate. Ammonium sesquicarbonate. Water. Ammonium sulphate. 2Al2H„O0 + 9CO,. Aluminium hydrate. Carbon dioxide. No. 1 is the reaction which takes place when cream of tartar and soda, or a baking-powder composed of those substances, are used in baking. The solid product of the reaction is Rochelle salt. No. 2 is that which occurs between tartaric acid and soda, and is but seldom utilized. No. 3 is that between burnt potassium alum and soda. It is not utilized at present, as the ammonium alum is more economical. Nos. 4 and 5 are those which occur in alum baking-powders, the burnt ammonia alum be- ing anhydrous ammonium aluminium sulphate, or aluminium sulphate, ac- cording to the degree of heat used in its manufacture. The solid residues of the reaction are sodic sulphate and aluminium hydrate. No. 6 is a re- action very little used, owing to the inconvenience of handling a liquid, to the too rapid action of the substances upon each other, and to the danger of introducing arsenic with the acid. No. 7 is used to a certain extent, and has the advantage that the solid residue of the reaction is a normal constituent of the body. No. 8 is occasionally utilized as an adjunct to No. 5. In our opinion, while yeast is to be prefeired to any baking-powder, an alum-powder is in no way more liable to produce disturbances of digestion than one compounded of cream of tartar and soda. Referring to Equation 5, above, and taking the amount of powder generally used, 35 grains per pound of bread, it will be seen that that amount of powder, containing 9.26 grains of aluminum sulphate, when neutralized during baking, produces 11.5 grains of Glauber’s salt, 4.24 grains of aluminium hydrate, and 7.12 grains of carbon dioxide. On the other hand, a cream of tartar powder to produce, according to reaction above, the same quan- tity, 7.12 grains, of carbon dioxide, forms at the same time 33.98 grains of Rochelle salt. Assuming that one to two pounds is the average amount of bread consumed by an adult in twenty-four hours, there can be but little choice between taking on the one hand 4.24-8.48 grains of alumina and 11.5-23.0 grains of Glauber’s salt; and on the other hand, 33.98-67.96 grains of Rochelle salt. Indeed, there is more danger to be apprehended from the tendency of repeated small doses of Rochelle salt to render the urine alkaline and thus favor the formation of phosphatic calculi, than from any supposed deleterious action of alumina, whose local action, even in considerable doses, is that of a very mild astringent, and whose ab- sorption is very doubtful. Sodium Potassium Tartrate—Rochelle salt—Sel de seignette—Potassii et sodii tartras (U. S.)—Soda tartarata (Br.)—C4Ht06NaK + 4Aq—210 + 72 —is prepared by saturating hydropotassic tartrate with sodium carbonate. It crystallizes in large, transparent prisms, which effloresce superficially in dry air and attract moisture in damp air. It fuses at 70-80° (158°-176° F.), and loses 3 Aq at 100° (212° F.). It is soluble in H,0, the solutions being dextrogyrous, [a]D = +29°. 67. SALTS OF POTASSIUM. 309 Potassium Antimonyl Tartrate—Tarlarated antimony—Tartar emetic— Antimonii et potassii tartras (U. S.)—Antimonium tartaratum (Hr.)—C4H4 0,.K(Sb0)'—323—is prepared by boiling a mixture of 3 pts. Sb„03 and 4 pts. C4H406HK in H,,0 for an hour, filtering, and allowing to crystallize ; when required pure, it must be made from pure materials. It crystallizes in transparent, soluble, right rhombic octohedra, which turn white in air. Its solutions are acid in reaction, have a nauseating, me- tallic taste, are lrevogyrous, [aj D — +156°.2, and are precipitated by alco- hol. The crystals contain Aq, which they lose entirely at 100° (212° F.), and partially by exposure to air. It is decomposed by the alkalies, alka- line earths, and alkaline carbonates, with precipitation of Sb„03. The precipitate is redissolved by excess of soda or potash, or by tartaric acid. HC1, SO,H, and N03H precipitate corresponding antimonyl compounds from solutions of tartar emetic. It converts mercuric into mercurous chlo- ride. It forms double tartrates with the tartrates of the alkaloids. Potassium Cyanide—Potassii cyanidum (U. S.)—CNK—65—is ob- tained by heating a mixture of potassium ferrocyanide and dry C03K3 as long as effervescence continues ; decanting and crystallizing. It is usually met with in dull, white, amorphous masses ; odorless when dry, it has the odor of hydrocyanic acid when moist. It is deliquescent, and very soluble in H O ; almost insoluble in alcohol. Its solution is acrid, and bitter in taste, with an after-taste of hydrocyanic acid. It is very readily oxidized to the cyanate, a property which renders it valuable as a reducing agent. Solutions of CNK dissolve I, AgCl, the cyanides of Ag and Au, and many metallic oxides. It is actively poisonous, and produces its effects by decomposition and liberation of hydrocyanic acid (q. v.). Potassium Ferrocyanide—Yellow prussiate of potash—Potassii fer- rocyanidum (U. S.)-—Potassce prussias flam (Hr.)—[Fe(CN)JK4 + 3Aq— 367.9-|-54.—This salt, the source of the other cyanogen compounds, is manufactured by adding organic matter (blood, bones, hoofs, leather, etc.) and iron to C03K„ in fusion ; or by other processes in which the N is ob- tained from the residues of the purification of coal-gas, from atmospheric air, or from ammoniacal compounds. It forms soft, flexible, lemon-yellow crystals, permanent in air at ordi- nary temperatures. They begin to lose Aq at 60° (140° F.), and become anhydrous at 100° (212° F.). Soluble in H„0 ; insoluble in alcohol, which precipitates it from its aqueous solution. When calcined with KHO or C03 K„ potassium cyanide and cyanate are formed, and Fe is precipitated. Heated with dilute S04H,, it yields an insoluble white or blue salt, potas- sium sulphate and hydrocyanic acid. Its solutions form with those of many of the metallic salts insoluble ferrocyanides ; those of Zn, Pb and Ag are white, cupric ferrocyanide is mahogany-colored, ferrous ferrocyanide is bluish-white, ferric ferrocyanide (Prussian blue) is dark blue. Blue ink is a solution of Prussian blue in a solution of oxalic acid. Potassium Ferricyanide—Red prussiate of potash—Fe5(CN)]2Kc— 657.8—is prepared by acting upon the ferrocyanide with chlorine ; or, better, by heating the white residue of the action of S04H2 upon potassium ferrocyanide, in the preparation of hydrocyanic acid, with a mixture of 1 vol. NO.(H and 20 vols. H,0 ; the blue product is digested with HvO and potassium ferrocyanide, the solution filtered and evaporated. It forms red, oblique, rhombic prisms, almost insoluble in alcohol. With solutions of ferrous salts it gives a dark blue precipitate, Turnbull’s blue. 310 MANUAL OF CHEMISTRY. Analytical Characters. (1.) Platinic chloride, in presence of IIC1 : yellow ppt.; crystalline if slowly formed; sparingly soluble in H20, much less so in alcohol. (2.) Tartaric acid, in not too dilute solution : white ppt.; soluble in al- kalies and in concentrated acids. (3.) Hydrofluosilicic acid : translucent, gelatinous ppt.; forms slowly; soluble in strong alkalies. (4.) Perchloric acid : white ppt.; sparingly soluble in I120 ; insoluble in alcohol. (5.) Phosphomolybdic acid : white ppt.; forms slowly. (6.) Colors the Bunsen flame violet (the color is only observable through blue glass in presence of Na), and exhibits a spectrum of two bright lines : A = 7860 and 4045 (Fig. 14, No 3). Action of the Sodium and Potassium Compounds on the Economy. The hydrates of Na and of K, and in a less degree the carbonates, dis- integrate animal tissues, dead or living, with which they come in contact, and, by virtue of this action, act as powerful caustics upon a living tissue. Upon the,skin they produce a soapy feeling and in the mouth a soapy taste. Like the acids, they cause death, either immediately, by corrosion or perforation of the stomach ; or secondarily after weeks or months, by closure of one or both openings of the stomach, due to thickening, conse- quent upon inflammation. The treatment consists in the neutralization of the alkali by an acid, dilute vinegar, or lemon-juice ; or by an oil, olive-oil, or milk, with which it forms a soap. The other compounds of Na, if the acid be not poisonous, are without deleterious action, unless taken in excessive quantity. Common salt has produced paralysis and death in a dose of half a pound. The neutral salts of K, on the contrary, are by no means without true poisonous action when taken internally, or injected subcutaneously in sufficient quantities ; causing dyspnoea, convulsions, arrest of the heart’s action, and death. In the adult human subject, death has followed the ingestion of doses of 5 ss. - 3 j. of the nitrate, in several instances ; doses of 3 ij. - § ij. of the sul- phate have also proved fatal. Csesium—Symbol = Cs—Atomic weight — 132.6 ; and Rubidium—Symbol = Rb—Atomic weight = 85.3 —are two rare elements, discovered in 1860 by Kirchoff and Bunsen while examining spectroscopically the ash of a spring water. They exist in very small quantity in lepidolite. They combine with 0 and decom- pose H20 even more energetically than does K, forming strongly alkaline hydrates. Rb is characterized spectroscopically by two red and two violet bands (rubidue — dark-red) : A = 7800, 6297, 4216, and 4202 ; Cs by two blue bands {coesius = sky blue) : A = 4560 and 4597. SILVER. Symbol = Ag (ARGENTUM) —Atomic weight = 107.9— Molecular weight = 216 (?)—Sp. gr. = 10.4-710.54—Fuses at 1,000° (1,832° F.). Although silver is usually classed with the “noble metals,” it differs from Au and Pt widely in its chemical characters, in which it more closely resembles the alkaline metals. ANALYTICAL CHARACTERS. 311 When pure Ag is required, coin silver is dissolved in N03H and the di- luted solution precipitated with HC1. The silver chloride is washed until the washings no longer precipitate with silver nitrate ; and reduced either (1) by suspending it in dilute S04H3 in a platinum basin, with a bar of pure Zn, and washing thoroughly after complete reduction ; or, (2) by mix- ing it with chalk and charcoal (AgCl, 100 parts; C, 5 parts ; C03Ca, 70 parts) and gradually introducing the mixture into a red-hot crucible. Silver is a white metal ; very malleable and ductile ; the best known conductor of heat and electricity. It is not acted on by pure air, but is blackened in air containing a trace of H,S. It combines directly with Cl, Br, I, S, P, and As. Hot S04H2 dissolves it as sulphate, and N03H as nitrate. The caustic alkalies do not affect it. It alloys readily with many metals; its alloy with Cu is harder than the pure metal. Oxides.—Three oxides of silver are known : Ag40, Ag,,0, and Ag302. Silver Monoxide—Protoxide—Argenti oxidum—(U. S.; Br.)—AgO— 231.8—formed by precipitating a solution of silver nitrate with potash. It is a brownish powder; faintly alkaline and very slightly soluble in H20 ; strongly basic. It readily gives up its oxygen. On contact with ammo- nium hydrate it forms a fulminating powder. Chloride—AgCl—143.4—formed when HC1 or a chloride is added to a solution containing silver. It is white ; turns violet and black in sun- light ; volatilizes at 260° (500° F.) ; sparingly soluble in HC1; soluble in solutions of the alkaline chlorides, hyposulphides, and cyanides, and in am- monium hydrate. Bromide—AgBr ; and Iodide—Agl—are yellowish precipitates, formed by decomposing silver nitrate with potassium bromide and iodide. Argentic Nitrate—Argenti nitras (U.; S. Br.)—L\03Ag—169.9—is prepared by dissolving Ag in N03H, evaporating, fusing, and recrystalliz- ing. It crystallizes in anhydrous, right rhombic plates; soluble in H20. The solutions are colorless and neutral. In the presence of organic matter it turns black in sunlight. The salt, fused and cast into cylindrical moulds, constitutes lunar caus- tic, lapis infernalis; argenti nitras fusa (V’. S.). If, during fusion, the tem- perature be raised too high, it is converted into nitrite, O, and Ag; and if sufficiently heated leaves pure Ag. Dry Cl and I decompose it, with liberation of anhydrous N03H. It absorbs NH3 to form a white solid, NOaAg,3NH.t, which gives up its NHa when heated. Its solution is decomposed very slowly by H, with de- position of Ag. Argentic Cyanide—Argenti cyanidum (U. S.)—CNAg—133.9—is prepared by passing CNH through a solution of NOaAg. It is a white, tasteless powder ; gradually turns brown in daylight; insoluble in dilute acids ; soluble in ammonium hydrate, and in solutions of ammoniacal salts, cyanides, or hyposulphites. The strong mineral acids decompose it with liberation of CNH. Analytical Characters (1.) Hydrochloric acid : white, flocculent ppt.; soluble in NH4HO; in- soluble in NOH. (2.) Potash or soda : brown ppt.; insoluble in excess ; soluble in NH4 HO. (3.) Ammonium hydrate, from neutral solutions : brown ppt.; soluble in excess. 312 MANUAL OF CHEMISTRY. (4.) Hydrogen sulphide or ammonium sulphydrate : black ppt. ; in- soluble in NH4HS. (5.) Potassium bromide : yellowish-white ppt. ; insoluble in acids, if not in great excess ; soluble in NH4HO. (6.) Potassium iodide : same as KBr, but the ppt. is less soluble in nh4ho. Action on the Economy. Silver nitrate acts both locally as a corrosive, and systemically as a true poison. Its local action is due to its decomposition by contact with organic substances, resulting in the separation of elementary Ag, whose deposition causes a black stain, and liberation of free N03H, which acts as a caustic. When absorbed, it causes nervous symptoms, referable to its poisonous action. The blue coloration of the skin, observed in those to whom it is administered for some time, is due to the reduction of the metal under the combined influence of light and organic matter ; especially of the latter, as the darkening is observed, although it is less intense, in internal organs. In acute poisoning by silver nitrate, sodium chloride or white of egg should be given; and, if the case be seen before the symptoms of corrosion are far advanced, emetics. AMMONIUM COMPOUNDS. The ammonium theory.—Although the radical ammonium, NH(, has probably never been isolated, its existence in the ammoniacal com- pounds is almost universally admitted. The ammonium hypothesis is based upon the following facts: (1) the close resemblance of the ammoni- acal salts to those of K and Na ; (2) when ammonia gas and an acid gas come together, they unite, without liberation of hydrogen, to form an am- moniacal salt; (3) the diatomic anhydrides unite directly with dry am- monia with formation of the ammonium salt of an amido acid : Sulphur trioxide. S03 + 2NH3 = S03(NH2)(NH4) Ammonia. Ammonium sulphamate. (4) when solutions of the ammoniacal salts are subjected to electrolysis, a mixture having the composition NH3 + H is given off at the negative pole ; (5) amalgam of sodium, in contact with a concentrated solution of am- monium chloride, increases much in volume, and is converted into a light, soft mass, having the lustre of mercury. This ammonium amalgam is de- composed gradually, giving off ammonia and hydrogen in the proportion NH3 + H ; (6) if the gases NH3 + H, given off by decomposition of the amalgam, exist there in simple solution, the liberated H would have the ordinary properties of that element; if, on the other hand, they exist in combination, the H would exhibit the more energetic affinities of an ele- ment in the nascent state. The hydrogen so liberated is in the nascent state. Compounds of Ammonium. Ammonium Hydrate—Caustic ammonia—NH4HO—35—has never been isolated, probably owing to its tendency to decomposition: NH HO = NH3 + H20. It is considered as existing in the so-called aqueous solutions SALTS OF AMMONIUM. 313 of ammonia. These are colorless liquids ; of less sp. gr. than H20 ; strongly alkaline ; and having the taste and odor of ammonia, which gas they give off on exposure to air, and more rapidly when heated. They are neutralized by acids, with elevation of temperature and formation of ammoniacal salts. The Aqua ammonice {U. S.) and Liq. Ammonice (Br.) are such solutions. Su phides.—Four are known : (NH4)2S ; (NH4)aS, ; (NH4)2S4 ; an 1 (NH J,,S5; as well as a sulphydrate (NH4)HS. Ammonium Sulphydrate—NH4HS—51—is formed in solution by satu- rating a solution of NH4HO with H2S; or anhydrous by mixing equal volumes of dry NH3 and dry H,S. The anhydrous compound is a colorless, transparent, volatile and soluble solid ; capable of sublimation without decomposition. The solution when freshly prepared is colorless, but soon becomes yellow from oxidation and formation of ammonium disulphide and hyposulphite, and finally de- posits sulphur. The sulphides and hydrosulphide of ammonium are also formed during the decomposition of albuminoids, and exist in the gases formed in burial vaults, sewers, etc. Ammonium Chloride—Sal ammoniac—Ammonii chloridum (U. S. ; Br.)—NH4C1—53.5—is obtained from the ammoniacal water of gas- works. It is a translucid, fibrous, elastic solid ; salty in taste, neutral in reaction ; volatile without fusion or decomposition ; soluble in HaO. Its solution is neutral, but loses NHS and becomes acid when boiled. Ammonium chloride exists in small quantity in the gastric juice of the sheep and dog ; also in the perspiration, urine, saliva, and tears. Ammonium Bromide—Ammonii bromidum (U. S.)—(NHjBr—98 —is formed either by combining NH3 and HBr ; by decomposing ferrous bromide with NH4HO ; or by double decomposition between KBr and S04 (NH4)2. It is a white, granular powder, or crystallizes in large prisms, which turn yellow on exposure to air ; quite soluble in H20 ; volatile with- out decomposition. Ammonium Iodide—Ammonii iodidum (U. S.)—NH4I — 145 — is formed by union of equal volumes of NH3 and HI ; or by double decom- position of KI and S04(NH4)2. It crystallizes in deliquescent, soluble cubes. Salts of Ammonium. Ammonium Nitrate—Ammonii nitras (U. S.)—N03(NH4)—80—is prepared by neutralizing NO ,H with ammonium hydrate or carbonate. It crystallizes in flexible, anhydrous, six-sided prisms ; very soluble in H20 with considerable diminution of temperature ; fuses at 150° (302° F.), and decomposes at 210° (410° F.), with formation of nitrous oxide : N03(NH4) = N20 + 2 H.O. If the heat be suddenly applied or allowed to surpass 250° (482° F.), NH3, NO, and N20 are formed. When fused it is an active oxidant. Sulphates—Ammonic Sulphate—Diammonic sulphate—Ammonii sul- phas (U. S.)—S04(NH4), —132—is obtained by collecting the distillate from a mixture of ammoniacal gas liquor and lime in SO,H2. It forms anhydrous, soluble, rhombic crystals ; fuses at 140° (284° F.), and is decomposed at 200° (392° F.) into NH3 and SO.H (NH4). Hydroammonic Sulphate—Mono-ammonic sulphate—Bisulphate of ammo- nia—SO)H(NH1)—115—is formed by the action of SO„H,, on It crystallizes in right rhombic prisms, soluble in H20 and alcohol. 314 MANUAL OF CHEMISTKY. Ammonium Acetate—C2H302(NHJ—77—is formed by saturating acetic acid with NH,, or with ammonium carbonate. It is a white, odor- less, very soluble solid ; fuses at 86° (186°.8 F.), and gives off NH3 ; then acetic acid, and finally acetamide. Liq. ammonii acetatis = Spirit of Min- dererus is an aqueous solution of this salt. Carbonates.—Ammonic Carbonate—Diammonic carbonate—Neutral am- monium carbonate—CO.(NH )2 + Aq—96 + 18—has been obtained as a white crystalline solid. In air it is rapidly decomposed into NH3 and COH(NH4). Hydro ammonic Carbonate — Monoammonic carbonate—Acid carbonate of ammonia—COaH(NH4)—79—is prepared by saturating a solution of NH HO or ammonium sesquicarbonate with C03. It crystallizes in large, rhombic prisms ; quite soluble in H20. At 60° (140° F.) it is decomposed into NH3 and C02. Ammonium Sesquicarbonate—Sal volatile—Preston salts—Ammonii car- bonas (U. S.)—Ammonioe carbonas (Br.)—(C03)3(NH4)4H2—254—is pre- pared by heating a mixture of NH4C1 and chalk, and condensing the pro- duct. It crystallizes in rhombic prisms; has an ammoniacal odor and an alkaline reaction ; soluble in H.,0. By exposure to air or by heating its solution it is decomposed into H30, NH3, and C03H(NH4). Analytical Characters. (1.) Entirely volatile at high temperatures. (2.) Heated with KHO, the ammoniacal compounds give off NHS, re- cognizable : (a) by changing moist red litmus to blue ; (b) by its odor ; (c) by forming a white cloud on contact with a glass rod moistened with HC1. (3.) With platinic chloride : a yellow, crystalline ppt. (4.) With hydro-sodic tartrate, in moderately concentrated and neutral solution : a white, crystalline ppt. Action on the Economy. Solutions of the hydrate and carbonate act upon animal tissues in the same way as the corresponding Na and K compounds. They, moreover, disengage NH3, which causes intense dyspnoea, irritation of the air pas- sages, and suffocation. The treatment indicated is the neutralization of the alkali by a dilute acid. Usually the vapor of acetic acid or of dilute HC1 must be adminis- tered by inhalation. n. THALLIUM GKOUP. THALLIUM. Symbol —'ll—Atomic weight = 203.7 — sp. gr.— 11.8-11.9—Fuses at 294° (561° P.)—Discovered by Crookes (1861). A rare element, first obtained from the deposits in flues of sulphuric acid factories, in which pyrites from the Hartz were used. It resembles Pb in appearance and in physical properties, but differs entirely from that element in its chemical characters. It resembles Au in being univalent and trivalent, but differs from it, and resembles the alkaline metals in being readily oxidized, in forming alums, and in forming no acid hydrate. It differs from the alkaline metals in the thallic compounds, which contain Tlw. It is character- ized spectroscopically by a bright green line—A — 5349. COMPOUNDS OF CALCIUM. 315 m. CALCIUM GBOUP. Metals of the Alkaline Earths. Calcium—Strontium—Barium. The members of this group are bivalent in all their compounds ; each forms two oxides : MO and MOa ; each forms a hydrate having well- marked basic characters. CALCIUM. Symbol — Ca—Atomic weight = 40—Molecular weight — 80 (?)—Sp. gr. = 1.984—Discovered by Davy in 1808—Name from calx = lime. Occurs only in combination, as limestone, marble, chalk (C03Ca); gypsum, selenite, alabaster (S04Ca), and many other minerals. In bones, egg-shells, oyster-shells, etc., as (P04)2Ca3 and C03Ca, and in many vegetable structures. The element is a hard, yellow, very ductile, and malleable metal; fusi- ble at a red heat ; not sensibly volatile. In dry air it is not altered, but is converted into CaH203 in damp air ; decomposes HaO; burns when heated in air. Compounds of Calcium. Calcium Monoxide—Quick lime—Lime—Calx (U. S.; Br.)—CaO— 56—is prepared by heating a native carbonate (limestone) ; or, when re- quired pure, by heating a carbonate prepared by precipitation. It occurs in white or grayish, amorphous masses ; odorless ; alkaline ; caustic ; almost infusible ; sp. gr. 2.3. With H,0 it gives off great heat and is converted into the hydrate (slacking). In air it becomes air-slacked, falling into a white powder, having the composition C03Ca, CaH,02. Calcium Hydrate—Slacked lime—Calds hydras (Br.)—CaH202—74 —is formed by the action of H20 on CaO. If the quantity of H,,0 used be one-third that of the oxide, the hydrate remains as a dry, white, odorless powder ; alkaline in taste and reaction ; more soluble in cold than in hot H20. If the quantity of H.,0 be greater a creamy or milky liquid remains, cream or milk of lime ; a solution holding an excess in suspension. With a sufficient quantity of H,0 the hydrate is dissolved to a clear solution, which is lime water—Liquor calcis (V. S.; Br.). The solubility of CaH202 is diminished by the presence of alkalies, and is increased by sugar or man- nite: Liq. calc, saccharatus (Br.). Solutions of CaH303 absorb C03 with for- mation of a white deposit of C03Ca. Calcium Chloride—Caldi chloridum (U. S. ; Br.)—CaCl2—111—is obtained by dissolving marble in HC1: CaC03 + 2HC1 = CaCl2 + H20 4- CO,. It is bitter; deliquescent; very soluble in H20 ; crystallizes with 6 Aq, which it loses when fused, leaving a white, amorphous mass ; used as a drying agent. Chloride of Lime—Bleaching powder—Calx chlorata (U. S.; Br.)—is a mixture composed chiefly of CaCl2 and calcium hypochlorite (C10)2Ca ; pre- pared by passing Cl over CaH303, maintained in excess. It is a grayish 316 MANUAL OF CHEMISTRY. white powder ; bitter and acrid in taste ; soluble in cold H20 ; decomposed by boiling H.,0, and by the weakest acids with liberation of CL It is de- composed by C02 with formation of C03Ca, and liberation of hypochlorous acid, if it be moist; or of Cl, if it be dry. A valuable disinfectant. Salts of Calcium. Calcium Sulphate—S04Ca—136—occurs in nature as anhydrite; and with 2 Aq in gypsum, alabaster, selenite ; and in solution in natural waters. Terra alba is ground gypsum. It crystallizes with 2 Aq in right rhombic prisms ; sparingly soluble in H O, more soluble in H.,0 containing free acid or chlorides. When the hydrated salt (gypsum) is heated to 80° (176° F.), or more rapidly between 120°-130° (248°-266° F.), it loses its Aq and is converted into a white, opaque mass ; which, when ground, is plaster-of-Paris. ' The setting of plaster when mixed with H20, is due to the conversion of the anhydrous into the crystalline, hydrated salt. The ordinary plastering should never be used in hospitals, as, by reason of its irregularities and porosity it soon becomes saturated with the transferrers of septic disease, be they germs or poisons, and cannot be thoroughly purified by disinfect- ants. Plaster surfaces may, however, be rendered dense and be highly polished, so as to be smooth and impermeable, by adding glue and alum, or an alkaline silicate to the water used in mixing. Phosphates.—Three are known: (P04)2Ca3 ; (P04H)2Ca2; and (P04 H2)2Ca. Teicalcic Phosphate—Tribasic or neutral phosphate—Bone phosphate— Calcii phosphas prmcipitatus (U. S.)—Calcis phosphas (Br.)—(P04)2Ca3— 310—occurs in nature in soils, guano, coprolites, phosphorite, in all plants, and in every animal tissue and fluid. It is obtained by dissolving bone-ash in HC1, filtering, and precipitating with NH HO ; or by double decomposi- tion between CaCl, and an alkaline phosphate. When freshly precipitated it is gelatinous; when dry, a light, white, amorphous powder; almost in- soluble in pure H.,0; soluble to a slight extent in H O containing am- moniacal salts, or NaCl or N03Na ; readily soluble in dilute acids, even in H20 charged with carbonic acid. It is decomposed by SO ,H„ into S04Ca and (P04H2)2Ca. Bone-ash is an impure form of (P04)2Ca3, obtained by calcining bones, and used in the manufacture of P and of superphosphate. Dicalcic Phosphate— (P04H).,Ca2 + 2 Aq—272 + 36—is a crystalline, insoluble salt; formed by double decomposition between CaCl2 and P04 HNa2 in acid solution. Monocalcic Phosphate—Acid calcium phosphate—Superphosphate of lime— (PO4 a w-a w-a w-a a a w j a W a a a Tartrate. i (S04)4(A12)(NH4)2 = W; (S04)4(A12)K2 = W. 2 As(NH4)C14 = W; Pt(NH4)Cl6 = W-I. * P04HNa(NH4) = W; P04MgfNH4) = A. * (804)2FeWTI4)2 = W: (S04)2Cu (NH4)2 = W. 5 C4H40(iK(NH4) = W. 6 SbOCl = A. 7 Sb203 = soluble in HC1, not in NOsH. 8 Sb2S3 = Sol. in hot HC1, slightly in NOsH. * C4H406K(Sb0) = W. 10BiOCl = A. NOs(BiO) = A. 12 (S04)4(Cr2)K2 = W. 73 CoS = easily sol. in NO.H, very slowly in HC1. (C4H4Os)4(Fe2)K2 = W MnOa = sol. in HC1; insol. in N03H. Mercnram- moniuni chloride = A. 17 Basic sulphate = A. 18 HsrS = insol. in HOI and in N03H, sol. in aq. regia. 19 See 13. 20 PtKClg = W-A. 21 Only soluble in N03H. 22 gn sulphides = sol. in hot. IIC1; oxidized, not dissolved by NO;iH. Sublimed SnCl4 only sol. in aq. regia. 23 Easily sol. in N03H, difficultly in HC1. Au2S = insol. in HC1 and in NO,H, sol. iii aq. regia. AuBr3, AuC13, and Au(CN)3 = w; Aula = a. PtS2 = insol. in HC1, slightly sol. in hot N03H; sol. in aq. regia. PtBr4, PtCl4, Pt(CN)4, (N03)4Pt, (C204)2Pt, (S04)2Pt = w; Pt02 = a ; Ptl4 = i.' WEIGHTS AND MEASURES. 355 TABLE II.—WEIGHTS AND MEASURES. Measures of Length. 1 millimetre = 0.001 metre = 0.0394 inch. 1 centimetre = 0.01 “ = 0.3937 “ 1 decimetre =0.1 “ = 3.9371 inches. 1 METRE = 39.3708 “ 1 decametre = 10 metres = 32.8089 feet. 1 hectometre = 100 “ = 328.089 “ 1 kilometre = 1000 “ = 0.6214 mile. Inch. Millimetres. Ve4 = 0.3819 l/at = 0.7638 Vl8 = 1-5875 Vs = 3.175 V4 = 6.® Va = 12.7 1 = 25.4 Inches. Centimetres. 2 = 5.08 3 = 7.62 4 = 10.16 5 - 12.70 6 = 15.24 7 = 17.78 8 = 20.32 Inches. Centimetres 9 = 22.86 10, = 25.40 11! = 27.94 12 = 30.48 18 = 45.72 24 = 60.96 36 = 91.44 Measures of Capacity. 1 millilitre = 1 c.c. = 0.001 litre = 0.0021 U. S. pint. 1 centilitre = 10 “ = 0.01 “ = 0.0211 “ “ 1 decilitre = 100 “ =0.1 “ = 0.2113 “ “ 1 LITRE = 1000 = 1.0567 “ quart. 1 decalitre = 10 litres = 2.6418 “ galls. 1 hectolitre = 100 “ = 26.418 “ “ 1 kilolitre = 1000 “ = 264.18 F|. C.C. 1 = 0.06 2 = 0.12 3 = 0.19 4 = 0.25 5 = 0.31 6 = 0.37 7 = 0.43 8 = 0.49 9 = 0.55 10 = 0.62 11 = 0.68 12 - 0.74 13 = 0.80 14 = 0 86 15 = 0.92 16 = 0.99 17 = 1.05 18 = 1.11 19 = 1.17 20 = 1.23 FI. C.C. 21 = 1.29 22 = 1.36 23 = 1.42 24 = 1.48 25 = 1.54 26 = 1.60 27 = 1.66 28 = 1.73 29 = 1.79 30 = 1.85 31 = 1.91 32 = 1.98 33 = 2.04 34 = 2.10 35 = 2.16 36 = 2.22 37 = 2.28 38 = 2.34 39 = 2.40 40 = 2.46 FI. c.c. 41 = 2.52 42 = 2.58 43 = 2.66 44 = 2.72 45 = 2.77 46 = 2.84 47 = 2.90 48 = 2.96 49 = 3.02 50 = 3.08 51 = 3.14 52 = 3.20 53 = 3.26 54 = 3.32 55 = 3.39 56 = 3.46 57 = 3.52 58 = 3.58 59 = 3.64 60 = 3.70 FI 3. c.c. 1 = 3.70 2 = 7.39 3 = 11.09 4 = 14.79 5 - 18.48 6 = 22.18 7 = 25.88 8 = 29.57 FI?. 1 = 29.57 2 = 59.14 3 = 88.67 4 = 118.24 5 = 147.81 6 = 177.39 7 = 206.96 8 = 236.53 9 as 266.10 10 - 295.68 FI ?. J0.0. 11 = 326 25 12 = 354.82 13 = 384.40 14 = 413.97 15 = 443.54 16 = 473.11 O. Litres. 1 = 0.47 2 = 0.95 3 = 1.42 4 = 1.89 5 = 2.36 6 = 2.84 7 = 3.31 8 = 3.79 9 = 4.26 10 = 4.73 11 = 5.20 12 = 5.67 356 MANUAL OF CIIEMISTKY. Weights, 1 milligram = 0.001 gram = 0.015 grain Troy. 1 centigram = 0.01 “ = 0.154 “ “ 1 decigram =0.1 “ = 1.543 “ 1 GRAM = 15.432 grains “ 1 decagram = 10 grams = 154.324 “ “ 1 hectogram = 100 “ = 0.268 lb. 1 kilogram = 1000 “ = 2.679 lbs. “ Grains. Grams. V94 = 0.001 7H = 0.002 Vis = 0.004 7» = 0.008 J/4 = 0.016 7a = 0.032 1 = 0.065 2 = 0.130 3 = 0.194 4 = 0.259 5 = 0.324 6 = 0.389 7 = 0.454 8 = 0.518 9 = 0.583 10 = 0.648 11 = 0.713 12 = 0.778 13 = 0.842 14 = 0.907 15 = 0.972 16 = 1.037 17 = 1.102 18 = 1.166 19 = 1.231 20 = 1.296 Grains. Grams. 21 = 1.361 22 = 1.426 23 = 1.458 24 = 1.555 25 = 1.620 26 = 1.685 27 = 1.749 28 = 1.814 29 = 1.869 30 = 1.944 31 = 2.009 32 = 2.074 33 = 2.139 34 = 2.204 35 = 2.268 36 = 2.332 37 = 2.397 38 = 2.462 39 = 2.527 40 = 2.592 41 = 2.657 42 = 2.722 43 = 2.787 44 = 2.852 45 = 2.916 46 = 2.980 Grains. Grams. 47 = 3.046 48 = 3.110 49 = 3.175 50 = 3.240 51 = 3.305 52 = 3.370 53 = 3.434 54 = 3.499 65 = 3.564 56 = 3.629 57 = 3.694 68 = 3.758 59 = 3.823 60 = 3.888 3 1 = 3.888 2 = 7.776 3 = 11.664 4 = 15.552 5 = 19.440 6 = 23.328 7 = 27.216 8 = 31.103 5 Grams. 1 = 31.103 2 = 62.207 3 = 93.310 4 = 124.414 6 = 165.517 6 = 186.621 7 = 217.724 8 = 248.823 9 = 279.931 10 = 311.035 11 = 342.138 12 = 373.250 lbs. Kilos. 1 = 0.373 2 = 0.747 3 = 1.120 4 = 1.493 5 = 1.866 6 = 2.240 7 = 2.613 8 = 2.986 9 = 3.359 10 = 3.733 INDEX. Acenaphthalene, 244 Acetamide, 146 Acetone, 142 Acetones, 141 Acetyl, 141 hydrate, 130 hydride, 139 methylide, 143 Acetylene, 209 Acid, acetic, 130 aconitic, 212 acrylic, 160 adipic, 182 allanturic, 199 amidoacetic, 146 amidobutyric, 152 amidocaproic, 153 amidoproprionic, 152 amidovalerianic, 153 angelic, 161 arachaic, 204 arachic, 135 arsenic, 90, 92 arsenious, 88, 90 auric, 274 azelaic, 182 benic, 129 benzoic, 216, 238 bismuthic, 292 boracic, 103 boric, 103 bromic, 61 butylactic, 168 butylformic, 133 butyric, 132 cachoutannic, 250 caffeic, 250 caffetannic, 250 camphic, 215 campholic, 215 capric, 134 caproic, 134 caprylic, 134 carbolic, 234 carbonic, 169, 171 cerotic, 138 chenocholic, 150 chenotaurocholic, 150 chloric, 60 chlorous, 59 Acid, cholalic, 150 choleic, 149 cholesteric, 243 cholic, 148, 150 cholonic, 148 chromic, 275 cinnamic, 216 citraconic, 212 citric, 211 convolvulinic, 249 cresylic, 235 crotonic, 161 cyanic, 247 cyanuric, 188 decylic, 134 delphinic, 133 deoxyglutanic, 182 dextrotartaric, 210 dichloracetic, 131 dichromic, 275 dilactic, 181 disulphanilic, 241 disulphuric, 70 ditartaric, 211 dithionic, 68 elaidic, 162 erythroglucic, 210 ethalic, 134 ethyldiacetic, 142 ethylenolactic, 180 ethylidenelactic, 180 ethylsulphuriG, 136 ferric, 279 formic, 129 gadinic, 206 gallic, 239 gallotannic, 249 glucic, 217 glyceric, 201 glycerophosphoric, 208 glycocholic, 148 glycolamic, 146 glycolic, 180 heptylic, 134 hexylic, 134 hippuric, 238 hysenic, 129 hydrobromic, 60 hydrochloric, 58 hydrocyanic, 246 358 INDEX. Acid, hydroferricyanic, 248 hydroferrocyanic, 248 hydrofluoric, 55 hydrofluesilicic, 272 hydriodic, 62 hydrosulphuric, 65 hydrosulphurous, 68 hyoebolic, 150 hyoglycocholic, 150* hyotaurocholic, 1501 hypobromoms, 61 hypochlorous, 59 hypogaic, 204 hyponitric, 75 hyponitrous, 76 hypophosphorous, 84 hyposulphureus, 68 iodic, 63 ssethionic, 167 isethioimric, 167 isobutylformic, 133 isobutyric, 133 isopropylacetic, 133 isovaleric, 133 itaconic, 212 lactic, 180 Itevotartari®, 210 lauric, 134 laurostearie, 134 Jeucic, 153 linoleic, 205 lithic, 196 malei®, 201 malic, 201 malonic, 183 margaric, 135 meconie, 256 melassic, 217 melissic, 129 mellitio. 238 metaboric, 103 metantimonic, 100 metantimonous, 100* metaphosphoric, 85' metarsenic, 90 metastannic, 294 metatungstic, 273 methylcrotonic, 161 monocbloracetic, 131 morintannic, 250 muriatic, 58 myristic, 134 nicotic, 183 nitric, 77 nitrohydrochloric, 58 nitromuriatic, 58 nitrosonitric, 77 nitrous, 76 nonylic, 134 Nordhausen, 70 octylic, 134 cenanthylic, 134 oleic, 162 orthoantimonic, 100 orthoarsenic, 90 Acid, orthoboric, 103 orthophosphoric, 84 osmic, 273 oxalic, 182 oxaluric, 199 oxybenzoic, 238 oxyphenie, 230 oxy valeric, 168 palmitic, 134 parabanic, 198 paralactic, 180 pelargonic, 134 pentathionic, 68 perbromic, 61 perchloric, 60 periodic, 63 phenic, 234 phenylsulphurous, 231 phlorylic, 230 phocenic, 133 phosphomolybdic, 251, 273 phosphoric, 84 phosphorous, 84 phosphotungstic, 273 phthalic, 238 picric, 235 pimelic, 182 pivalic, 134 plumbic, 288 pneumic, 167 prehnitic, 238 propionic, 132 propylacetic, 133 protocatechuic, 250 prussic, 246 pyroantimonic, 100 pyroarsenic, 90 pyrobismuthie, 292 pyroboric, 103 pyrogallic, 237 pyroligneous, 130 pyrophosphoric, 85 pyrosulphuric, 70 pyrotartaric, 211 pyroterebic, 160 pyruvic, 211 quercitannic, 250 quinic, 237 quinotannic, 250 quinovatic, 249 quinovic, 249 racemic, 210 rocellic, 182 rosolic, 230, 234 salicylous, 239 salicylic, 238 santonic, 249 sarcolactic, 180 sebacic, 182 silicotungstic, 273 stannic, 294 stearic, 135 suberic, 182 succinic, 184 sulphanilic, 241 INDEX. 359 Acid, sulphocyanic, 247 sulphoglucic, 217 sulphovinic, 136 sulphuric, 68 sulphurous, 67 sulphydric, 65 tannic, 249 tartaric, 210 tartralic, 211 taurocarbamic, 167 taurocholic, 149 terephthalic, 237 tetrathionic, 68 trichloracetic, 131 trichromic, 275 trimellitic, 238 trimethylacetic, 134 trinitrophenic, 234, 235 trithionic, 68 ulmic, 217 uric, 196 urous, 199 valerianic, 133 veratric, 238 Acids, 19 amido, 146 biliary, 148 diatomic and dibasic, 183 diatomic and monobasic, 168 fatty, 129 monobasic, 129 valerianic, 133 Aconitine, 260 Acridine, 230 Acrolein, 160 Action on the economy of acetic acid, 132 of alcohol, 121 of ammonia, 314 of antimony, 102 of arsenic. 91 of atropine, 260 of barium, 320 of bismuth, 293 of carbolic acid, 234 of carbon dioxide, 177 of carbon disulphide, 179 of carbon monoxide, 169 of chloral. 140 of chloroform, 113 of chromium compounds, 276 of copper, 329 of ether, 129 of hydrocyanic acid, 247 of hydrogen sulphide, 66 of iodine, 61 of lead, 290 of mercury, 335 of mineral acids, 59 of nitrogen monoxide, 74 of nitrogen tetroxide, 76 of opium, etc,, 256 of oxalic acid, 183 of phenol, 234 of phosphoric acids, 85 Action of phosphorus, 80 of potassium, 310 of silver, 312 of sodium, 310 of strychnine, 259 of sulphuric acid, 70 of zinc, 324 Addition, 110, 157, 104 Adipocere, 262 After-damp, 111 Air, 72 ammonia in, 72 carbon dioxide in, 72, 171 confined, 174 solids in, 73 water in, 72 Alanine, 152 Albane, 214 Albumin, acid, 266 alkali, 266 egg, 263 in urine, 263 serum, 263 vegetable, 264 Albuminates, 263 Albuminoids, 260, 263 Albuminose, 266 Alcohol, 119, 121 absolute, 121 allylic, 158 benzoic, 232, 236 benzylic, 232, 236 butyl, 125 camphyl, 215 cerylic, 126 cetylic, 126 cholesteric, 242 cinnamic, 242 ethylic, 119 menthylic, 215 methylic, 118 propylic, 125 vinic, 119 Alcoholic beverages, 122 radicals, 110, 116 Alcohols, 116 amylic, 118, 125 aromatic, 236 butyric, 125 diatomic, 116, 165 monoatomic, 115 primary, 116 secondary, 117 tertiary, 117 tetratomic, 210 triatomic, 200 Aldehyde, 139 acetic, 139 acrylic, 160 allylic, 160 benzoic, 239 butyric. 138 campholic, 214 caproic, 138 caprylic, 138 360 INDEX. Aldehyde, crotonic, 161 isobutyric, 138 oenanthylic, 138 palmitic, 138 propionic, 138 salicylic, 240 valerianic, 138 Aldehydes, 138 Aldol, 161 Ale, 123 Algaroth, powder of, 101 Alizarin, 245 Alkaline metals, 297 Alkaloids, 251 cinchona, 256 detection of, 252 fixed, 254 opium, 254 strychnos, 258 volatile, 253 Alkarsin, 157 Allantoin, 199 Allotropy, 33 Alloxan, 199 Allyl, 158 hydrate, 158 oxide, 159 sulphide, 159 sulphocyanate, 159 Allylene, 209 Allylic series, 157 Alphenols, 236 Alumina, 284 Aluminates, 284 Aluminium, 283 chloride, 284 hydrate, 284 oxide, 284 salts, 284 silicates, 285 sulphate, 284 Alums, 285 Amanitine, 144 Amides, 145, 186 Amido acids, 146 benzol, 241 Amines, 143, 240 Ammonia, 73 Ammonias, compound, 143 Ammonium, 312 acetate, 314 bromide, 313 carbonates, 314 chloride, 313 compounds, 312 hydrate, 312 iodide, 313 nitrate, 313 salts of, 313 sulphates, 313 sulphides, 313 sulphydrate, 313 theory, 312 urates, 196 Amorphism, 29 Amphoteric elements, 274 Amygdalin, 248 Amyl nitrate, 137 nitrite, 137 Amylene, 165 Amyloid, 267 Amyloses, 225 Amylum, 225 Analysis, 8, 46, 349 Analytical characters of alkaloids, 251 of acetates, 131 of albumin, 263 of alcohol, 121 of aluminium, 285 of ammonium, 314 of aniline, 241 of antimony, 102 of arsenic, 94 of atropine, 260 of barium, 320 of bismuth, 293 of bromides, 63 of brucine, 259 of cadmium, 325 of calcium, 319 of carbolic acid, 234 of chlorides, 63 of chloroform, 113 of cholesterin, 243 of chromium, 276 of cobalt, 326 of codeine, 255 of coniine, 253 of copper, 328 of cyanides, 246 of glucose, 219 of gold, 274 of hydrogen, 42 of hydrogen dioxide, 54 of iodides, 63 of iron, 282 of lead, 290 of leucin, 154 of lithium, 297 of magnesium, 322 of manganese, 277 of mecaric acid, 256 of mercury, 334 of morphine, 255 of narceine, 255 of narcotine, 256 of nickel, 325 of nicotine, 254 of nitrates, 78 of nitrous fumes, 76 of oxalates, 182 of oxygen, 43 of ozone, 44 of phenol, 234 of phosphates, 85 of phosphorus, 81 of picric acid, 235 of potassium, 310 of quinine, 267 of silver, 312 INDEX. 361 Analytical characters of sodium, 303 of strychnine, 258 of sulphates, 70 of sulphides, 66 of sulphites, 67 of thebaine, 256 of tin. 295 of tyrosine, 154 of uric acid, 197 of zinc, 324 Anhydride, antimonic, 100 antimonous, 99 arsenic, 89 arsenious, 88 boric, 103 carbonic, 171 chlorous, 59 chromic, 275 hypochlorous, 59 molybdic, 273 nitric, 76 nitrous, 75 phosphoric, 84 phosphorous, 83 plumbic, 288 silicic, 272 sulphuric, 68 sulphurous, 67 tungstic, 273 Anhydrides, 47, 138 Aniline, 241 Anthracene, 244 Anthracite, 104 Antimony, 99 antimonate, 100 black, 101 butter of, 100 cinnabar, 101 crocus of, 99 crude, 99 glass of, 101 intermediate oxide, 100 liver of, 101 pentachloride, 101 pentasulphide, 101 pentoxide, 100 protochloride, 100 trichloride, 100 trioxide, 99 trisulphide, 101 Antimonyl, 99 Antiseptics, 262 Apomorphine, 255 Aqua ammonise, 312 chlori, 57 fortis, 77 regia, 58, 77 Arabin, 229 Argol, 306 Aromatic series, 230 Arsenamine, 87 Arsenia, 87 Arsenic, 86, 88 acids, 89 disulphide, 90 Arsenic, flour of, 88 oxides, 88 pentasulphide, 91 pentoxide, 89 sulphides, 90 tribromide, 91 trichloride, 91 trifluoride, 91 triiodide, 91 tri oxide, 88 trisulphide, 90 white, 88 Arsenical greens, 92 Arsines, 156 Artiads, 15 Atom, 12 Atomic heat, 14 theory, 9 weight, 11, 12 Atomicity. 15, 168 Atropine, 260 Auric chloride, 274 Aurin, 234 Auripigmentum, 90 Azote, 71 Azulin, 234 Baking-powders, 307 Balsams, 216 Barium, 319 carbonate, 320 chloride, 320 compounds, 320 hydrate, 320 nitrate, 320 oxides, 320 salts, 320 sulphate, 320 Baryta, 319 Bases, 19 Basicity, 19. 168 Bassorin, 229 Beer, 123 Benylene, 209 Benzene, 230 Benzine, 111, 230 Benzol, 230 Benzoline, 111 Benzyl hydrate, 236 hydride, 239 Beryelium, 283 Betaine, 144 Beverages, alcoholic, 122 Bile acids, 148 pigments, 270 Bilifuscin, 270 Biliprasin, 271 Bilirubin, 270 Biliverdin, 270 Binary compounds, 23 Bismuth, 291 hydrates, 292 nitrate, 292 oxides-, 292 salts, 292 Beer, 123 362 INDEX. Bismuth, trichloride, 292 Bismuthyl, 291 carbonate, 292 nitrate, 292 Bleaching-powder, 315 Boiling-point, 7 Bone, 316 ash, 316 black, 104 phosphate, 316 Borax, 301 Borneene, 215 Borneol, 215 Boron, 102 oxide, 103 Brandy, 124 Bromal, 121, 141 Bromine, 60 Bromoform, 114 Brucine, 259 Butalanine, 153 Butter, 207 Cacodyle, 157 Cadmium, 325 Caesium, 310 Caffeine, 258 Calcium, 315 carbonate, 318 chloride, 315 hydrate, 315 monoxide 815 oxalate. 318 phosphates, 816 salts, 316 sulphate, 315 n vntPQ 1 Qv Calculi, 198, 199, 317, 318, 348 Calomel, 331 Camphene, 215 Camphol, 215 Camphor, 214 Borneo, 215 Japan, 214 laurel, 214 monobromo, 215 Camphors, 214 Caouchene, 213 Caoutchouc, 213 Carbamide, 187 Carbimide, 186 Carbinol, 118 Carbohydrates, 216 Carbon, 103 compounds of, 106 dichloride, 114, 165 dioxide, 171 disulphide, 179 monoxide, 169 oxysulphide, 179 tetra bromide, 114 tetrachloride, 114 trichloride, 114 Carbonyl chloride, 169 Carnine, 200 Casein, gluten, 2C6 milk, 265 serum, 264, 266 Cellulin, 229 Cellulose, 229 Cerasin, 229 Cerium, 386 oxalate, 336 Ceruse, 289 Ceryl hydrate, 126 cerotate, 138 Cetaceum, 137 Cetene, 137 Cetine, 137 Cetyl hydrate, 126 palmitate, 137 Chalk, 318 Charcoal, 104 animal, 104 Chemistry, 1 China wax, 138 Choline, 144 Chloral, 121, 139 alcoholate, 140 hydrate, 140 Chlorine, 56 monoxide, 59 peroxide, 60 tetroxide, 60 trioxide, 59 Chlorocarbon, 114 Chloroform, 112 Cholesterin, 242 Chondrin, 268 Chromium, 275 chlorides, 275 oxides, 275 sulphates, 275 Chrysene, 245 Cicutine, 253 Cider, 124 Cinchonidine, 258 Cinchonine, 258 Cinnabar, 331 Cinnamene, 242 Cinnatnol, 242 Classification, 28 Coagulated albumins, 267 Coal, 104 Cobalt, 325 Codeine, 255 Coke, 104 Collagen, 267 Collodion, 229 Colophony, 216 Combustion, 43 Composition, 1, 25 Compounds, 8 Conicine, 253 Coniine, 253 Constitution, 25, 108 Copper, 326 acetates, 328 arsenite, 328 carbonates, 328 INDEX. 363 Copper, chlorides, 327 hydrates, 327 nitrate, 327 oxides, 326 sulphate, 327 sulphides, 327 Corallin, 234 Corrosives, 59 Corrosive sublimate, 332 Cosmoline, 112 Creasol, 235 Creasote, 235 Creatine, 155 Creatinine, 155 Cresol, 235 Cresylol, 232, 235 Cristallin, 241 Crith, 40 Crotonylene, 209 Cryptidine, 230 Cryptolysis, 120 Cryptolytes, 120, 268 Crystallization, 29 Crystalloids. 34 Cumene. 232 Cumol, 232 Cupric chloride, 327 oxide, 326 nitrate, 327 sulphate, 227 sulphide, 327 Cuprous chloride, 327 oxide, 326 sulphide, 327 Cyanogen, 245 hydrate, 247 hydride, 246 Cymene, 215, 233 Cvmol, 233 Daturine, 260 Decantation, 341 Deliquescence, 46 Deodorizers, 262 Deoxidation, 41 Dextrin, 119, 227, 228 Dextrogyrous, 38 Dextrose, 216 Diallyl, 158 Dialysis, 34 Diamides, 186 Diamines, 185 Diamond, 103 Diastase, 119, 216 Dibromomethyl bromide, 114 Diehloromethane, 112 Dichlormethyl chloride, 112 Dicyanogen, 245 Didymium. 336 Dietbylamine, 143 Diffusion, 34, 41 Digitaleni*, 248 Digitalin, 248 Digitonin, 248 Digitoxin, 248 Diiodomethyl iodide, 114 Dimethylamine, 144 Dimethyl arsine, 157 Dimethyl benzene, 232 Dimethylia, 144 Dimorphism, 33 Disinfectants, 262 Disocryl, 161 Divisibility, 7 Drying, 343 Dutch liquid, 165 Dynamite, 203 Dyslysin, 150 Ebonite, 214 Efflorescence, 47 Elastin. 268 Elayl, 164 Eleoptene, 214 Electrolysis, 17 Electro-negative, 18 Electro-positive, 18 Elements, 8, 12 acidulous, 55 amphoteric, 274 basylous, 297 typical, 39 Elutriation, 318 Emulsin, 248 Emulsion, 204 Equations, 16 Equivalence, 15 Equivalents, 9 Erbium, 336 Erythrine, 210 Erythrite, 210 Eserine, 260 Essence of bitter almonds, 239 of garlic, 159 of mirbane, 233 of mustard, 159 Essences, 212, 213 j Ethal, 126, 138 Ethene, 164, 209 chlorhydrate, 166 chlorhydrin. 166 chloride, 165 glycol, 166 oxide, 166 Ether, 127 acetic, 137 allylic, 159 ethylic, 127 hydrobromic, 115 hydrochloric, 115 hydriodic, 115 me thy lie, 127 muriatic, 115 nitric, 136 nitrous, 136 petroleum, 111 pyroacetic, 142 sulphuric, 127, 136 Etherification, 127 364 INDEX. Etherine, 137 Etherol, 137 Ethers, 126 compound, 135 haloid, 112 mixed, 127 simple, 126 Ethyl acetate, 137 bromide, 115 carbinol, 125 chloride, 115 hydrate, 119 iodide, 115 nitrate, 136 nitrite, 136 oxide, 127 sulphates, 136, 137 sulphide, 156 sulphydrate, 156 Ethylene, 165 alcohol, 165 bichloride, 165 glycol, 165 hydrate, 165 oxide, 166 Eucalyptene, 215 Eucalyptol, 215 Evaporation, 343 Fats, 203, 206 phosphorized, 208 Fermentation, 120 Ferments, animal, 268 Ferric acetates, 281 bromide, 280 chloride, 280 citrate, 282 ferrocyanide, 282 hydrates, 279 iodide, 280 nitrates, 280 oxide, 278 phosphate, 281 pyrophosphate, 281 sulphates, 280 sulphides, 279 tartrate, 282 Ferrous acetate, 281 bromide, 280 carbonate, 281 chloride, 279 ferricyanide, 282 hydrate, 279 iodide, 280 lactate, 281 nitrate, 280 oxalate, 281 oxide, 278 phosphate, 281 sulphate, 280 sulphide, 279 tartrate, 282 Fibrin, 267 Fibrinogen, 264 Fibrinoplastic matter, 264 Filtration, 52, 342 Fire-damp, 111 Fluids, 6 compressible, 6 incompressible, 6 Fluorene, 244 Fluorine, 55 Fluviale, 214 Foods, vegetable, 227 Formulas, 16, 25 empirical, 25 general, 108 graphic, 25 of constitution, 25 typical, 25 Formyl bromide, 114 chloride, 112 iodide, 114 Fuchsine, 241 Fusel oil, 125 Fusing-point, 7 Gadinin, 206 Gaduin, 206 Galactose, 222 Galena, 288 Gallium, 286 Gasoline, 111 Gelatin, 267 sugar of, 146 Gelatinoids, 260, 267 Gin, 125 Glauber’s salt, 299 Gliadin, 266 Globin, 270 Glucinium, 283 Glucosan. 217 Glucose, 216 Glucoses, 216 Glucosides, 217, 248 Glycerin, 200 ethers of, 201 Glycin, 146 Glycocol, 146 Glycocols, 146 Glycogen, 228 Glycol, 166 benzyl, 238 Glycol lide, 180 Glycols, 165 Glycyrrhetin. 249 Glycyrrhizin, 249 Gold, 274 trichloride. 274 Grape-sugar, 216 Graphite, 104 Gravity, 2 specific, 2 Guanine, 199 Guaranine, 258 Gum, British, 228 Gum resins, 216 Gums, 229 Gun-cotton, 229 Gutta, 214 INDEX. Gutta percha, 214 Gypsum, 315 ILematin, 270 Hsematocrystallin, 269 Hsemochromogen, 270 Haemoglobin, 269 Halogens, 55 Heat, atomic, 14 latent, 7 specific, 35 Hemialbumin. 261 Hemihedral, 32 Hemiprotein. 261 Homologous series, 107 Hydracids, 19 Hydrates, 19, 21, 46 Hydrobilirubin, 271 Hydrocarbons, 110, 163 first series, 110 second series, 164 third series, 209 fourth series, 212 fifth series, 230 sixth series, 242 seventh series, 243 eighth series, 243 ninth series, 244 tenth series, 244 eleventh series, 244 higher series, 245 series of, 163 non-saturated, 164 saturated, 110 Hydrogen, 39 antimonide, 99 arsenides, 87 bromide, 60 chloride, 58 cyanide, 246 dioxide, 54 fluoride, 55 heavy earburetted, 164 iodide, 62 light earburetted, 111 nitride, 73 oxide, 44 peroxide, 54 phosphides, 83 silicide, 272 sulphide, 65 Hydrometer, 4 Hydroquinone, 237 Hyoscyamine, 260 Hypoxanthine, 199 Ignition, 344 Illuminating gas, 209 Imides, 186 Indestructibility of matter, 2 Indican, 271 Indiglucin, 271 Indigogen, 271 Indium, 286 Inosite, 222 Inulin, 222 Iodine, 61 Iodoform, 114 Iridium, 296 Iridoiine, 230 Iron, 277 acetates, 281 bromides, 280 carbonate, 281 chlorides, 279 citrates, 282 compounds of, 278 ferricyanide, 282 ferrocyanide, 282 hydrates, 279 iodides, 280 lactate, 281 nitrates, 280 oxides, 278 phosphates, 281 pyrophosphate, 281 salts, 280 sulphates, 280 sulphides, 279 tartrates, 282 Isethionamide, 166 Isomerism, 108 Isomorphism, 32, 108 Isoprene, 213 Ivory black, 104 Jalapin, 249 Jalapinol, 249 Javelle water, 305 Jet, 104 Kaolin, 285 Kelp, 61 Keratin, 268 Kermes mineral, 101 Kerosene, 111 dimethyl, 142 Ketones, 141 King’s yellow, 90 Kyanol, 241 Lactide, 181 Lactine, 225 Lactose, 225 Lsevogyrous, 38 Laevulosan, 222 Laevulose, 222 Lamp-black, 104 Lanthanium, 336 Latent heat, 7 Laughing-gas, 74 Laurene, 230 Law of Ampere, 11 of Avogadro, 11 of definite proportions, 8 of Dulong and Petit, 14 of multiple proportions, 9 of reciprocal proportions, 9 periodic, 286 Laws of Dalton, 7 366 INDEX. Laws of Gay Lussac, 10 Lead, 287 acetates, 289 black, 104 carbonate, 289 chloride, 289 chromate, 289 compounds of, 288 dioxide, 288 glycocholate, 149 iodide, 289 monoxide, 288 nitrates, 289 oxides, 288 peroxide, 288 protoxide, 288 puce oxide, 288 red, 288 salts, 289 sulphate, 289 sulphide, 288 Lecithins, 144, 208 Legumin, 266 Lethal, 138 Leucine, 153 Leucoline, 230 Lichenin. 229 Lignin, 229 Lime, 315 chloride of, 315 slacked, 315 water, 315 Liqueurs, 125 Litharge, 288 Lithium, 297 bromide, 297 carbonate, 297 chloride, 297 hydrate, 297 oxide, 297 urates, 197 Lutidine, 230 Maclurin, 250 Magenta, 241 Magnesia, 321 alba, 322 Magnesium, 321 carbonates, 322 chloride, 321 compounds, 321 hydrate, 321 oxide, 321 phosphates, 321 salts, 321 sulphate, 321 Maltose, 225 Manganese, 276 chlorides, 277 oxides, 276 salts, 277 Mannitose, 222 Marsh-gas. Ill Massicot, 288 Mauvein, 242 Meconine, 254 Melanin, 271 Melissin, 138 Menthol, 215 Mercaptan, 156 Mercaptides, 156 Mercurammonium chloride, 333 Mercuric chloride, 332 cyanide, 333 iodide, 333 oxide, 331 sulphide, 331 Mercurous chloride, 331 iodide, 333 oxide, 330 Mercury, 330 chlorides, 331 iodides, 333 oxides, 330 nitrates, 333 salts, 333 sulphates, 334 sulphides, 331 Mesitylene, 233 Mesoxalylurea, 199 Metachloral, 140 Metallocyanides, 248 Metalloids, 28 Metals, 28 Metamerism, 108 Methal, 138 Methane, 111 Methenyl bromide, 114 chloride, 112 iodide, 114 Methyl benzene, 232 bromide, 114 carbinol, 119 chloride, 112 coniine, 253 glycocol, 147 hydrate, 118 hydride, 111 iodide, 114 nitrate, 136 nitrite, 136 oxide, 127 Methylamine, 143 Methylene bichloride, 112 Methylia, 143 Milk, 265 Minium, 288 Mixtures, 9 Molecule, 7, 11 Molybdenum, 273 Monamides, 144 Mon amines, 143 Monochlorm ethyl chloride, 112 Morphine. 254 Mucin, 268 Murexid, 198 Muscarine. 144 Myosin, 264 Myricyl hydrate, 126 Myrosin, 159 INDEX. 367 NAPHTIIA, 111 wood, 119 Naphthalene, 243 Naphthydrene, 243 Narceine, 255 Narco tine. 255 Nascent state, 41 Neurine, 144, 208 Nickel, 325 Nicotine, 253 Niobium, 273 Nitre, 304 Nitro-benzene, 233 benzol, 233 cellulose, 229 glycerin, 202 Nitrogen, 71 bromide, 78 chloride, 78 dioxide, 75 iodide, 78 monoxide, 74 pentoxide, 76 peroxide, 75 protoxide, 74 tetroxide, 75 trioxide, 75 Nitrous fumes, 75 oxide, 74 Nomenclature, 22 Occlusion, 41 Oils, 203 distilled, 213 essential, 213 fixed, 204 volatile, 212, 213 Olefiant gas, 164 Olefines, 164 Olein, 162 Oleoresins, 216 Optically active bodies, 38 Organic substances, 106 Orpiment, 90 Osmium, 273 Oxacids, 19 Oxalylurea, 198 Oxy acids, 19 Oxycholine, 144 Oxygen, 42 Oxyhasmoglobin, 269 Oxyneurine, 144 Oxysalts, 20 Ozone, 44 Palladium. 295 Pancreatin. 269 Paraffin, 111 Paraffines, 110 Paraglobulin, 4 Paraldehyde, 139 Paramorphine. 256 Parapeptone, 266 Paris green. 92, 328 Pearlash, 306 Pentene, 165 Peonin, 234 Pepsin, 268 Peptone, 266 Perissads, 15 Petroleum, 111 ether, 111 Petrolatum, 112 Phenicin, 234 Phenol, 234 benzylic, 235 cresylic, 235 cymylic, 236 Phenols, 238 Phenyl, 240 hydrate, 234 hydride, 230 Phenylamine, 240, 241 Phloroglucin, 237 Phosgene, 169 Phosphamine, 83 Phosphines, 156 Phosphonia, 83 Phosphorus, 79 bromides, 86 fluorides, 86 iodides, 86 oxides, 83 oxychloride, 86 pentachloride 86 pentoxide, 84 trichloride, 86 trioxide, 83 Phyeite, 210 Physostigmine, 260 Picnometer, 4 Picohne, 230 Plasmine. 264 Plaster of-Paris, 316 Platinic chloride, 295 Platinum, 295 Plumbago, 104 Plumbates, 288 Poisons, 59 mineral, 98 Polarimetry, 38 Polymerism, 108 Porcelain, 285 Porter, 123 Potash, 304, 306 Potassa, 304 Potassium, 303 acetate, 306 aluminate, 284 arsenite, 92 bichromate, 305 bromide, 304 carbonates, 306 chlorate, 305 chloride, 304 cyanide, 309 dichromate, 305 ferricyanide, 309 ferrocyanide, 309 hydrate, 304 368 INDEX. Potassium, hypochlorite, 305 iodide, 304 myronate, 159 nitrate, 305 oxalates, 306 oxides, 304 permanganate, 306 pyrosulphate, 305 salts, 305 sulphates, 305 sulphides, 304 sulphite, 305 tartrates, 307 urates, 197 Potato spirit, 125 Precipitation, 52, 341 Proof spirit, 121 Propyl-benzene, 232 hydrate, 125 Propylamine, 144 Protein bodies, 260 Protein, 261 Prussian blue, 282 Ptomaines, 260 Ptyalin, 268 Putrefaction, 261 Pyrene, 230, 245 Pyridine, 230 Pyrodextrin, 227 Pyrogallol, 237 Pyroxam, 227 Pyroxylin, 229 Quick-lime, 315 Quinicine, 258 Quinidine, 258 Quinine, 257 Quinone, 237 Quinova red, 250 Quinovin, 249 Radicals, 18, 25, 107 Reagents, 338 Realgar, 90 Reduction, 41 Residues, 18 Resins, 214, 216 Reteue, 230 Rhigolene, 111 Rhodium, 296 Ricinine, 204 Rock crystal, 272 oil, 111 Rosaniline, 241 Rosin, 216 Rubidine, 230 Rubidium, 310 Rum, 125 Ruthenium, 296 Rutylene, 209 Saccharides, 224 Saccharoses, 223 Salfranin, 242 Sal ammoniac, 313 volatile, 314 Salceratus, 306 Salicin, 239, 249 Salicylol, 240 Saligenin, 237, 249 Salt, Epsom, 321 common, 298 Glauber’s, 300 of lemon, 306 of tartar, 306 Rochelle, 308 Seidlitz, 321 sorrel, 306 Saltpetre, 305 Chili, 300 Salts, 19, 20 basic, 25 double, 25 haloid, 20 oxy, 25 sub, 25 Santonin, 249 Saponification, 203 Sarcine, 199 Sarcosine, 147 Scandium, 286 Scheele’s green, 92, 328 Schweinfurth green, 92, 328 Sea salt, 298 Secalin, 144 Selenium, 70 Septicine, 260 Serin, 264 Silex, 272 Silicates, 272 Silicic oxide, 272 Silicibromoform, 272 Silicichloroform, 272 Silicon, 272 chloride, 272 Silver, 311 bromide, 311 chloride, 311 cyanide. 311 iodide, 311 nitrate, 311 oxides, 311 Soaps, 208 Soda, 297, 302 Sodium, 298 acetate, 302 aluminate, 284 arsenite, 92 borates, 301 bromide, 299 carbonates, 302 chloride, 298 compounds, 298 glycocholate, 149 hydrate, 298 hypochlorite, 302 hyposulphite, 301 iodide, 300 manganate, 302 INDEX. 369 Sodium, nitrate, 300 oxides, 298 permanganate, 302 phosphates, 301 salts, 300 silicates, 301 sulphates, 300 sulphite, 300 tungstate, 273 urates, 197 Solanidine, 249 Solanine, 249, 259 Solution, 33, 45, 340 chemical, 33, 46 physical, 33, 45 saturated, 46 simple, 33, 45 supersaturated, 46, 300 Spectroscopy, 35 Spermaceti, 137 Spirits, 124 methylated, 119 of wine, 119 pyroxylic, 118 wood, 118 Stannic compounds, 294 Stannous compounds, 294 Starch, 225 States of matter, fi Stearoptenes, 214 Steel, 278 Stercobilin, 271 Stethal, 138 Stibamine, 99 Stibines, 156 Stilbene, 244 Strontium, 319 Strychnine, 258 Styrol, 242 Styrolene, 242 Sublimation, 7 Sugar, beet, 223 candy, 223 cane, 223 diabetic, 216 of gelatin, 146 grape, 216 inverted. 224 of lead, 289 liver, 216 maple, 223 milk, 225 muscle, 222 tests for, 219 Sulphethylates, 156 Sulphobases, 19 Sulphobenzide, 231 Sulphur, 64 dioxide, 67 trioxide, 68 Superphosphate, 316 Supersaturation, 46, 300 Symbols, 16 Synthesis, 8, 46 Syntonin, 266 Tannin, 249 Tantalum, 273 Tar, 230 Tartar, 807 emetic, 309 Taurine, 149, 166 Teeth, 317 Tellurium, 71 Terebenthene, 212 Terpine, 212, 215 Terpinol, 215 Terra alba, 315 Test, biuret, 193 Boettger’s, 220 Fehling’s, 220, 221 fermentation, 220 Frezenius’ and von Babo’s, 98 Gallois’, 223 Heller’s, 263 Marsh’s, 95 Moore’s, 219 Mulder-Neubauer’s, 219 murexid, 198 Pettenkofer’s, 150 Beinsch’s, 95 Scherer’s, 223 Trommer’s, 219 Thallium, 314 Thebaine, 256 Theine, 258 Thialdine, 139 Thorium, 336 Thymol, 236 Tin, 294 chlorides, 294 compounds, 294 hydrates, 294 oxides, 294 Tincal, 301 Titanium, 293 Toluene, 232 Toluidine, 232 Toluol, 232 Texiresin, 248 Traumaticine, 214 Trehalose, 216 TributyriD, 202 Tricaprin, 202 Tricaproin, 202 Tricaprylin, 202 Trichloraldehyde, 139 Triethylamine, 143 j Trimargarin, 202 Trimethylamine, 144 Trimethylia, 144 Trimorphism, 33 Trinitro-glycerin, 202 Trinitro-phenol, 235 Triolein, 202 Tripalmitin, 202 Triple phosphate, 321 Tristearin, 202 Trivalerin, 202 Trypsin, 269 Tungsten, 273 cane, 223 370 INDEX. Turnbull’s blue, 282, 309 Turpentine, 212 Tutty, 323 Typical elements, 39 Tyrosine, 154 Urea, 187 determination of, 193 nitrate, 189 oxalate, 189 tests for, 193 Ureas, compound, 195 Ureids, 195, 198 Urinary pigments, 271 Urinometer, 4 Urobilin, 271 Uroxanthin, 271 Valence, 15 Valerene, 165 Valerylene, 209 Valylene, 212 Vanadium, 273 Vanadyl, 273 Vapors, 6 Varech, 61 Vaselin, 112 Veratrine, 260 Verdigris, 328 Vermilion, 331 Vinegar, 131 wood, 118 Viridine, 230 Vitelin, 264 Vitriol, blue, 327 green, 280 oil of, 69 white, 324 Volumetric analysis, 346 Washing, 341 Water, 44 chlorides in, 49 glass, 300 hardness of, 49 impurities of, 48 metals in, 50 mineral, 52 Water, natural, 47 of constitution, 47 of crystallization, 47 organic matter in, 49 oxygenated, 54 purification of, 51 solids in, 48 Wax, 188 Weighing, 845 Weight, 2 absolute, 2 atomic, 11 molecular, 14 relative, 2 specific, 2 of gases, 5 of liquids, 4 of solids, 4 of vapors, 5 Weights, 355 Whiskey, 124 White-lead, 290 precipitate, 331 Wine, 123 oil of, 136 spirits of, 119 Wolfram, 273 Xanthine, 199 Xenols, 236 Xylene, 232 Xylenols, 236 Xyloidin, 227 Xylol, 232 Yeast, 119 Ytterbium, 336 Yttrium, 386 Zinc, 323 butter of, 323 carbonates, 324 chloride, 323 compounds, 323 hydrate, 323 oxide, 323 sulphate, 324 Zirconium, 293