THE MEDICAL STUDENT’S MANUAL OF C H E M I S T R Y BY R. A. WITTHAUS, A.M., M.D., Professor of Chemistry and Physics in the University of the City of New York ; Professor of Chem- istry and Toxicology in the University of Vermont; Member of the Chemical Societies of Paris and Berlin ; Member of the Amorican Chemical Society; Fellow of the Amer- ican Academy of Medicine; of the N. Y. Academy of.Medicine; of the American Association for the Advancement of Science, etc. THIRD EDITION. NEW YORK WILLIAM WOOD & COMPANY 1890 Copyright, 1890, WILLIAM WOOD & COMPANY ELECTROTYPED AND PRINTED BY THE PUBLISHERS’ PRINTING COMPANY 30 & 32 WEST I3TH STREET NEW YORK PREFACE TO THE PRESENT EDITION. The arrangement and classification followed in previous edi- tions have been continued. Those portions of the work dealing with chemical physics and with mineral chemistry have been extended in the light of dis- coveries announced since the appearance of the second edition. The orthography of certain words, as chlorin, chlorids, has been modified in accordance with the views expressed in the re- port of the committee of the Chemical Section of the American Association for the Advancement of Science (see Appendix A). That portion of the work treating of the chemistry of the car- bon compounds has been much extended and in great part re- written. The prominence given to this branch of the subject the author believes to be justified, notwithstanding its intricacy and the consequent difficulty of teaching it satisfactorily to medi- cal students, by reason of the intimate connection of organic chemistry with physiology and with modern pharmacy, and the rapidly increasing use of complex organic products, natural and synthetic, as medicines. R. A. W. New York, September 21st, 1890. PREFACE TO THE FIRST EDITION. In venturing to add another to the already long list of chemi- cal 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 stu- dents alike, the subsequent development of the study in its de- tails 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 subject 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 produce a work which should contain as much as possible of those portions 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 in- terest. The descriptions of processes of manufacture are there- fore made very brief, while chemical physiology and the chemis- try 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 under- standing of that which follows. A more extended study of phy- sics 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- VI PREFACE TO TIIE FIRST EDITION. books are to be noted. The elements are classed, not in metals and metalloids, 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. 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 experience in the laboratory, but merely as an outline sketch in aid thereto. Although the Manual puts forth no claim as a work upon an- alytical chemistry, we have endeavored to bring that branch of the subject rather into the foreground so far as it is applicable to medical chemistry. The qualitative characters of each element are given under the appropriate heading, and in the third part, a systematic scheme for the examination of urinary calculi is given. Quantitative methods of interest to the physician are also described in their appropriate places. In this connection the au- thor would not be understood as saying that the methods rec- ommended are in all instances 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 venerable practitioners who have survived their student days by a half-century, those weights have been introduced in brackets after the metric, as the value of degrees Fahrenheit have been made to follow those Centigrade. R. A. W. Buffalo, N. Y., September 16th, 1883. TABLE OF CONTENTS. PART I.—INTRODUCTION 1 General Properties of Matter 2 Indestructibility 2 Impenetrability. 2 Weight 2 Specific gravity 3 States of matter 9 Divisibility 10 Physical Characters of Chemical Interest 10 Crystallization 10 Allotropy 15 Solution, 15 Diffusion of liquids 17 Change of state 18 Specific heat 19 Thermometers 20 Spectroscopy 21 Polarimetry 25 Chemical effects of light 26 Galvanic electricity 27 Chemical Combination 30 Elements 30 Combination of elements 30 Atomic theory 32 Atomic and molecular weights 34 Valence or atomicity 38 Symbols, formulae, equations 39 Acids, bases and salts 41 Stoichiometry 44 Nomenclature 46 Radicals 49 Composition and constitution 50 Classification of elements 52 PAGE VIII TABLE OF CONTENTS. PAGE PART II.—SPECIAL CHEMISTRY 55 Typical Elements 55 Hydrogen 55 Oxygen 59 Ozone 62 Water 64 Hydrogen dioxid 77 Acidulous Elements 79 Chlorin Group 79 1’luorin , 79 Hydrogen fluorid 79 Chlorin 80 Hydrogen chlorid 83 Compounds of clilorin and oxygen 85 Bromin 86 Hydrogen bromid 87 Oxacids of bromin 87 Iodin 88 Hydrogen iodid 1 89 Chlorids of iodin 90 Oxacids of iodin 90 Sulphur Group 90 Sulphur 91 Hydrogen sulphid 92 Sulphur dioxid 95 Sulphur trioxid 96 Hyposulphurous acid 97 Sulphurous acid 97 Sulphuric acid 98 Thiosulphuric acid 100 Pyrosulphuric acid 100 Selenium and Tellurium 101 Nitrogen Group 101 Nitrogen 101 Atmospheric air 102 Ammonia 104 Hydroxylainin 105 Nitrogen monoxid 106 Nitrogen dioxid 106 Nitrogen trioxid 107 Nitrogen tetroxid 107 Nitrogen pentoxid 108 Nitrogen acids 108 Hyponitrous acid 108 Nitrous acid 108 TABLE OF CONTENTS IX Nitric acid 109 Compounds of nitrogen with the halogens Ill Phosphorus 112 Hydrogen phosphids 117 Oxids of phosphorus 118 Phosphorus acids 118 Compounds of phosphorus with the halogens 120 Arsenic 121 Hydrogen arsenids 122 Oxids of arsenic 123 Arsenic acids 125 Sulphids of arsenic 127 Haloid compounds of arsenic 127 Arsenical poisoning 128 Analytical 131 Antimony 137 Hydrogen antimonid 138 Oxids of antimony 138 Antimony acids 139 Chlorids of antimony 139 Sulphids of antimony HO Antimonial poisoning 141 Analytical 141 Boron Group 142 Boron 142 Carbon Group 143 Carbon 143 Silicon 145 Vanadium Group 146 Molybdenum Group 146 Amphoteric Elements. 148 Gold Group 148 Iron Group 148 Chromium 149 Manganese 150 Iron 162 Compounds of iron 153 Salts of iron 155 Aluminium Group 158 Glucinium 168 Aluminium 169 Scandium 132 Gallium 132 Indium 133 Uranium Group 133 PAGE X TABLE OE CONTENTS. PAGE Lead Group 163 Bismuth Group 168 Tin Group 171 Platinum Group 173 Basylous Elements 176 Sodium Group 176 Lithium 176 Sodium 177 Potassium 184 Silver 192 Ammonium 194 Thallium Group 197 Calcium Group 197 Calcium 197 Strontium 203 Barium 203 Magnesium Group 204 Magnesium 204 Zinc 207 Cadmium 209 Nickel Group 209 Copper Group 210 Copper 210 Mercury 215 Compounds op Carbon 222 Homologous series. 224 Isomerism 225 Classification of organic substances 226 Acyclic Hydrocarbons 229 First Series of Hydrocarbons—Paraffins 229 Haloid derivatives 232 Monoatomic alcohols 237 Simple ethers 251 Monobasic acids 254 Compound ethers 262 Aldehydes 266 Acetals 271 Ketones or acetones 271 Nitroparaffins 273 Monainins or amidoparaffins 274 Monainids 278 Amido acids 280 Azoparaffins—Cyanogen compounds 291 Sulphur derivatives 296 Compounds with other elements ... 298 TABLE OF CONTENTS. XI Ally lie series 300 Acrylic acids and aldehydes 303 Second Series of Hydrocarbons—Olefins 307 Diatomic alcohols 308 Diatomic, monobasic acids 311 Oxids and sulpliids of carbon 315 Diatomic, dibasic acids 326 Unsaturated acids 329 Compound ethers 330 Aldehydes and anhydrids 330 Amins 331 Amids 332 Compound ureas 343 Triatomic alcohols 348 Acids 350 Ethers.. 351 Fats and oils 353 Lecithins—Nerve-tissue 361 Diamids of the tartronic series 363 Third Series of Hydrocarbons 364 Tetratomic alcohols 365 Acids 365 Hexatomic alcohols 368 Carbohydrates 368 Glucoses 369 Saccharoses 376 Amy loses 380 Cyclic Hydrocarbons 387 Honobenzenic Hydrocarbons 389 Haloid derivatives 395 Phenols 396 Substituted phenols 399 Diatomic phenols 401 Triatomic phenols 403 Phenol dyes 404 Aromatic alcohols 404 Alplienols 405 Aldehydes 405 Ketones 406 Acids 407 Sul phonic acids 409 Nitro derivatives of benzene 410 Amido derivatives of benzene 411 Derivatives of anilin 412 Hydrazins 414 PAGE XII TABLE OF CONTENTS. Azo- and diazo- derivatives 414 Pyridin bases 415 Incomplete Benzenic Hydrocarbons 417 Alcohols 417 Indigo Group 418 Bi- and Poly-benzoic Hydrocarbons 421 Hydrocarbons with Indirectly United Benzene Nuclei. 421 Derivatives of phenylmethanes 421 Hydrocarbons with Directly United Benzene Nuclei.. 423 Substitution derivatives of naphthalene 424 Chinolin bases 426 Anthracene group 428 Derivatives of anthracene 428 Terebenthic Series 430 Compounds of Unknown Constitution 436 Glucosids 436 Alkaloids 439 Volatile alkaloids 442 Fixed alkaloids 443 Albuminoids and Gelatinoids 458 Animal Cryptolytes 469 Animal Coloring Matters 471 PART III.—CHEMICAL TECHNICS 475 General rules 475 Reagents 476 Glass tubing 477 Collection of gases 478 Solution 479 Precipitation, decantation, etc 479 Evaporation, drying, etc 482 Weighing 485 Measuring 486 Scheme for Analysis of Calculi 489 Appendix A.—Orthography and pronunciation 493 Appendix B.—Tables 502 Index 509 PAGE 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 substances, 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 attracts 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 pi-operties of that metal. The iron and a part of the oxygen have disappeared, and have been converted into a new sub- stance, differing from either ; there has been change in composi- tion, there has been chemical action. Changes wrought in mat- ter by physical forces, such as light, heat, and electricity, are temporary, and last only so long as the force is active ; except in the case of changes in the state of aggregation, as when a sub- stance is pulverized or fashioned into given shape. Changes in chemical composition are permanent, lasting 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 1 2 MANUAL OF OliEMISTKY. existence was first announced by Grove, in 1842. As, from chem- ical action, manifestations of every variety of physical force may be obtained : light, heat, and mechanical force from the oxida- tion 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 chem- ical union of chlorin and hydrogen ; by electrical action a decom- position of many compounds into their constituents is instituted, while instances are abundant of reactions, combinations, and de- compositions which require a certain elevation of temperature for their production. While, therefore, 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 has 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 accom- panied by corresponding 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. Impenetrability.—Although one mass of matter may penetrate another, as when a nail is driven into wood, or when salt is dis- solved in water; the ultimate particles of which matter is com- posed cannot penetrate each other, and, in cases like those above cited, the particles of the softer substance are forced aside, or the particles of one substance occupy spaces between the particles of the other. Such spaces exist between the ultimate particles of even the densest substances. 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 GENERAL PROPERTIES OF MATTER. 3 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 kinds of weight: absolute, apparent, and specific. The Absolute Weight of a body is its weight in vacuo. It is determined 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 counter- poising 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 displaced. 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 temperature adopted by ;oine continental writers and in the U. S. P. is 15° (59° F.). Other standard temperatures are 4° (89°.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. * As the sp. gr. of pure air (hydrogen = 1) is 14.42, the sp. gr. in terms of air X 14.42 — sp. gr. in terms of hydrogen. Thus, the sp. gr. of hydrochloric acid gas (A — 1) is 1.259. Its sp. gr. (H — 1) is therefore 1.259 X 14.42 — 36.31. 4 MANUAL OF CHEMISTRY. An aqueous solution of a solid heavier than water has a higher sp. gr. than pure water, the variation in sp. gr. following a regular but different rate with each solid. In a simple solution— one of common salt in water, for instance—the proportion of solid in solution can be determined from the sp. gr. In complex solutions, such as the urine, the sp. gr. does not indicate the proportion 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. Moreover, as urea is much in excess over other urinary solids, the oscillations in thesp. 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 elim- ination of urea, and consequently the activity of disassiinilation of nitrogenous material. To determine the sp. gr. of substances, dif- ferent 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. Ex- ample : Fig. 1. A piece of lead weighs in air 82.0 A piece of lead weighs in water 74.9 Loss in water 7.1 82.0 = 11.55 = sp. gr. of lead. The substance is in powder, insoluble in water.—The specific gravity bottle (Fig. 3), filled with water, and the powder, pre- viously 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 : GENERAL PROPERTIES OF MATTER. 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 ([357 = 7.65 = sp. gr. of iron 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 sub- stance being subtracted from the total loss. Example : A fragment of wood weighs 4.3946 A fragment of lead weighs 10.6193 Wood with lead attached weighs in air 15.0139 Wood with lead attached weighs in water 5.9295 Loss of weight of combination 9.0844 Loss of weight of lead in water (determined as above) 0.7903 Loss of weight of wood 8.2941 4.3946 n . , _____ = 0.529 = sp. gr. of wood. The substance is soluble in or decomposable by water.—Its spe- cific 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 2.257 = 1.141 X 0.758 = 0.865 = sp. gr. of potassium Liquids.—The sp. gr. of liquids is determined by the specific gravity balance, by the specific gravity bottle, sometimes called picnometer, or by the spindle or hydrometer. By the balance.—The liquid, previously brought to the proper temperature, is placed in the cylinder a (Fig. 2), and the plunger immersed in it, and attached to the arm of the balance. The weights are now adjusted, beginning with the largest, until the balance is in equilibrium. The sp. gr. indicated by the balance in Fig. 2 is 1.98. 6 MANUAL OF CHEMISTRY. By the bottle.—An ordinary analytical balance is used. A_bottle of thin glass (Fig. 3) is so made as to contain a given volume of water, siy 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.; 1-10 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. Fig. 2. 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 hydrometer most used by physi- cians is the urinometer (Fig. 4). 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. It should be tested by immersion in liquids of known sp. gr., and the error at differ- ent points of the scale should be noted on the box. The most convenient method of using the instrument is as follows : The cylinder, which should have a foot and rim, but no pouring lip, GENERAL PROPERTIES OF MATTER. 7 is filled to within an inch of the top ; the spindle is then floated and the cylinder completely filled with the liquid under exami- nation (Fig. 4). The reading is then taken at the highest point a, where the surface of the liquid comes in contact with the spindle.* 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 con- Fig. •!. sequently the result obtained will be too low if the urine or other liquid be at a temperature above that at which the instru- ment is intended to be used, and too high if below that tempera- ture. An accurate correction may he made for temperature in 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. Fig. 8. * 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 m opaque liquids, and the fact that readings are made upward, not downward. 8 MANUAL OP CHEMISTRY. Gases and Vapors.—The specific gravities of gases and va- pors are of great importance in theoretical chemistry, as from them we can determine molecular weights, in obedience to the law of Avogadro (p. 33). Gases.—The specific gravities of gases are obtained as follows : A glass flask of about 300 c.c. capacity, having a neck 20 centi- metres 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, h, 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 /tj j*\ - 760 (l+'0~003(iC7)—= T'l== the volume of the gasat 0° and 760 mm. 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 H , and the weight of the flask filled with air P', are now determined. From these results the weight, K, of the gas occupying the volume Vo is obtained by the formula : K P P + 760 (1+0.00366 t') x°-001293 The sp. gr. referred to air is found by the formula: K Vo XO. 001293 and that referred to hydrogen by the formula K Vo X 0.001293x0.00927 Vapors.—The specific gravity of vapors is best determined by Meyer's method, as follows : A small, light glass vessel (Fig. 5) is filled completely with the solid or liquid whose vapor density is to be determined and weighed ; from this weight that of the ves- sel is subtracted; the difference being the weight of the substance P. The small vessel and contents are now in- troduced into the large branch of the apparatus (Fig. 6), whose weight is then determined. The apparatus is now filled with mercury, 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.50 c.c. of some liquid whose boil- ing-point is constant and higher than that of the substance experimented on. When the liquid has been heated to active Fia. 5. GENERAL PROPERTIES OF MATTER. 9 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. 6), 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 until the smaller branch is completely tilled, 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 ; £=temperature of air ; H=barometric pressure reduced to 0°; A—difference in level of mercury in two branches of tube ; A= tension of vapor of mercury at T ; a=weight of mercury used ; q—weight of mercury required to fill the tube Fig. 5 ; r=weight of mercury remaining in the apparatus after heating. From these the specific gravity, air = 1, is obtained by the equation : P 760 (1+0.00867 T) 13.59 ~(H+A+ft') 0.0012932 \(a+q) 1+0.0000303 (T—t) }- —r ■{ 1+ 0.00018 (T—t) H [1+0.00018 t] The sp. gr. in terms of air=l may be reduced to sp. gr. referred to hydrogen=2, by dividing by 0.06927. States of Matter.—Matter exists in one of three states; solid, liquid, and gaseous. In the solid form, the particles of matter are comparatively close together, and are separated with more difficulty than are those of liquid or gaseous matter ; or in other words the cohesion of solid matter is greater than that of the other two forms. In the liquid, the particles are less firmly bound together, and are capable of freer motion about one an- other. In the gas, the mutual attraction of the particles disap- pears entirely, and their distance from each other depends upon the pressure to which the gas is subjected. The term fluid applies to both liquids and gases, the former being designated as incompressible, from the very slight degree to which their volume can be reduced by pressui-e. The gases are designated as compressible fluids, from the fact that their volume can be reduced by pressure, to an extent limited only by their passage into the liquid form. It is highly probable that all substances, which are not decom- posed when heated, are capable of existing in the three forms of solid, liquid, and gas. There are, however, some substances which are only known in two forms—as alcohol ; or in a single 10 MANUAL OF CHEMISTRY. form—as carbon; probably because we are as yet unable to pro- duce artificially a temperature sufficiently low to solidify the one, or sufficiently high to liquefy or volatilize the other. A vapor is an aeriform fluid into which a substance, solid or liquid at the ordinary temperature, is converted by elevation of temperature, or by diminution of pressure. Since the liquefaction of the so-called permanent gases, the distinction between gases and vapors is only one of degree and of convenience. A liquid is said to be volatile when, like ether, it is readily converted into vapor. It is said to be fixed if. like olive oil, it does not yield a vapor when heated. Certain solids are directly volatile, like camphor, passing from the condition of solid to that of vapor without liquefaction. Divisibility.—All substances are capable of be- ing separated, with greater or less facility, by mechanical means into minute particles. With suitable apparatus, gold may be divided into fragments, visible by the aid of the microscope, whose weight would be innjTroWTunnr of a grain ; and it is probable that when a solid is dissolved in a liquid .a still greater subdivision is attained. Although we have no direct experimental evi- dence of the existence of a limit to this divisibility, we are warranted in believing that matter is not infinitely divisible. A strong argument in favor of this view being that, after physical subdivision has reached the limit of its power with regard to compound substances, these may be further divided into dissimilar bodies by chemical means. The limit of mechanical subdivision is the molecule of the physi- cist, the smallest quantity of matter with which he has to deal, the smallest quantity that is capable of free existence. Fig. 6. Physical Characters of Chemical Interest. Crystallization.—Solid substances exist in two forms, amor- phous and crystalline. In the former they assume no definite shape ; they conduct heat equally well in all directions; they break irregularly; and, if transparent, allow light to pass through them equally well in all directions. A solid in the crystalline form has a definite geometrical shape ; conducts heat more read- ily in some directions than in others ; when broken, separates in certain directions, called planes of cleavage, more readily than in others; and modifies the course of luminous rays passing through PHYSICAL CHARACTERS OF CHEMICAL INTEREST. 11 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, by slow and gradual modification, may assume the crystalline form ; as vitreous arsenic trioxid {q. v.) passes to the crystalline variety. 2.) A fused solid, on cooling, crystallizes; as bismuth. 3.) When a solid is sublimed it is usually condensed in the form of crystals. Such is the case with arsenic trioxid. 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, espe- cially if it be agitated during the cooling, they are small. Most crystals may be divided by imaginary planes into equal, Fig. 7 Fig. 8. symmetrical halves. Such planes are called planes of symmetry. Thus in the crystals in Fig. 7 the planes ab ab, ac ae, 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 prin- cipal plane of symmetry; as in Fig. 8 the plane ab ab, containing the equal linear directions aa and bn. 12 MANUAL OF CHEMISTRY. 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. Upon the relations of these imaginary planes and axes a classi- fication 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 dode- cahedron. The crystals of this system expand equally in all directions when heated, and are not doubly refracting. II. The Right Square Prismatic, Pyramidal, Quadratic, Tetrag- onal, 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 ex < pand equally only in two directions when heated. They refract light doubly in all directions except through one axis of single refraction. III. The Rhombohedral or Hexagonal System includes crys- tals having four axes, three of which aa, aa, aa, Fig. 9, are of Fig. 9. PHYSICAL CHARACTERS OF CHEMICAL INTEREST. 13 equal length and cross each other at GO' 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 six-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 rectangular octa- hedron, and the right rectangular prism. The crystals of this Fig. 10. 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 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 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, expand equally in the directions of their three axes. They refract light doubly except in two axes. Secondary Forms.—The crystals occurring in nature or pro- duced artificially have some one of the forms mentioned above, or some modification of those forms. These modifications, or 14 MANUAL OF CHEMISTRY. 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 alternate faces are excessively developed, producing at length entire obliteration of the others, as shown in Fig. 12. Such crystals are said to be hemihedral. They can be developed only in a system having a principal axis. Isomorphism.—In many instances two or more substances crystallize in forms identical with each other, and, in most cases, such substances resemble each other in their chemical constitu- tion. They are said to be isomorphous. This identity of crystal- line form does not depend so much upon the nature of the ele- ments themselves, as upon the structure of the molecule. The protoxid and perbxid of iron do not crystallize in the same form, nor can they be substituted for each other in reactions without radically altering the properties of the resultant compound. On the other hand, all that class of salts known as alums are isomor- phous. Not only are their crystals identical in shape, but a crys- tal of one alum, placed in a saturated solution of another, grows Fig. 11. Fig. 12. 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, sul- phur, as obtained by the evaporation of its solution in carbon disulphid, forms octahedra, belonging to the fourth system. When obtained by cooling melted sulphur the crystals are PHYSICAL CHARACTERS OP CHEMICAL INTEREST. 15 oblique prisms belonging to the fifth system. Occasional in- stances of trimorphism, of the formation of crystals belonging to three different systems by the same substance, are also known. Many substances, on assuming the crystalline form, combine with a certain amount of water which exists in the crystal in a solid combination. Thus nearly half of the weight of crystallized alum is water. This water is called water of crystallization, and is necessary to the maintenance of the crystalline form, and frequently to the color. If blue vitriol be heated, it loses its water of crystallization, and is converted into an amorphous, white powder. Some crystals lose their water of crystallization on mere exposure to the air. They are then said to effloresce. Usually, however, they only lose their water of crystallization when heated. (See p. 66.) Allotropy.—Dimorphism apart, a few substances are known to exist in more than one solid form. These varieties of the same substance exhibit different physical properties, while their chem- ical qualities are the same in kind. Such modifications are said to be allotropic. One or more allotropic modifications of a sub- stance are usually crystalline, the other or others amorphous or vitreous. Sulphur, for example, exists not only in two dimor- phous 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 sub- stance 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 dis- solved are more or less modified. The dissolved substance cannot be obtained from the solution by simple evaporation of the sol- vent, unless the compound formed be decomposable, with forma- tion of the original substance, at the temperature of the evapora- tion. The act of chemical solution is usually attended by an elevation of temperature. The amount of solid, liquid, or gas which a liquid is capable of dissolving by simple solution depends upon the following condi- tions : MANUAL OF CHEMISTRY. 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 to 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 suffi- ciency from the atmosphere to form a solution; as calcium chlorid. Such substances are said to deliquesce. Other sub- stances are insoluble in water in any proportion ; as barium sulphate. Elementary substances (with the exception of chlorin) are insoluble, or sparingly soluble, in water. Substances rich in carbon are insoluble in water, but soluble in organic liquids. 2. The temperature usually has a marked influence on the solubility of a substance. 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 chlorals of barium and of potassium is directly in proportion to the increase of temperature. The solubility of sodium chlorid is almost imperceptibly increased by elevation of temperature. The solubility of sodium sulphate increases rapidly up to 33° (91°.4 F.), above which temperature it again diminishes. The solubility of gases in water is the greater the lower the temperature, and the greater 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 instances 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 'temperature contains a greater quantity of the solid than it could dissolve at that temperature. Such a solution is said to be supersaturated. The contact of particles of solid material with the surface of a supersaturated solution induces immediate crystallization, attended with eleva- tion of temperature. 3. The presence of other substances already dissolved.—If to a saturated solution of potassium nitrate, sodium chlorid be added, a further quantity of potassium nitrate may be dissolved. In this case there is double decomposition between the two salts, and the solution contains, besides them, potassium chlorid and sodium nitrate. 4. The presence of a second solvent.—If two solvents, a and b,. PHYSICAL CHARACTERS OF CHEMICAL INTEREST. 17 incapable of mixing with each other, be brought in contact with a substance which both are capable of dissolving ; neither a nor b takes 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 Fig. 13. they diffuse. Substances capable of crystallization, crystalloids, are much more diffusible than those which are incapable of crystal lization—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 inter- posed 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 passes into the inner vessel, and the crystalloid passes into the water in the outer vessel. By frequently chang- ing the water in the outer vessel, solutions of the albuminoids or of ferric hydrate, etc., almost entirely free from crystalloids, may be obtained. 18 MANUAL OF CHEMISTRY. Change of State—Latent Heat.—The passage of a substance from one form to another is always attended by the absorption or liberation of a definite amount of heat. In passing from the solid to the gaseous form, a body absorbs a definite amount of heat with each change of form. If a given quantity of ice at a temperature below the freezing-point of water be heated, its temperature gradually rises until the thermometer marks 0° (32° F.), at which i>oint it remains stationary until the last parti- cle of ice has disappeared. At that time another rise of the thermometer begins, and continues until 100° (212° F.) is reached (at 760 mm. of barometric pressure), when the water boils, and the thermometer remains stationary until the last particle of water has been converted into steam ; after which, if the applica- tion of heat be continued, the thermometer again rises. During these two periods of stationary thermometer, heat is taken up by the substance, but is not indicated by the thermometer or by the sense. Not being sensible, it is said to be latent, a term which is liable to mislead, as conveying the idea that heat is stored up in the substance as heat; such is not the case. During the periods of stationary thermometer the heat is not sensible as heat, for the reason that it is being used up in the work required to effect that separation of the particles of matter which consti- tutes its passage from solid to liquid or from liquid to gas. The amount of heat required to bring about the passage of a given weight of a given substance from the denser to the rarer form is always the same, and the temperature indicated by the thermometer during this passage is always the same for that sub- stance, unless in either case a modification be caused by a varia- tion in pressure. When a solid is liquefied it is said to fuse, or to melt. The degree of temperature indicated by the thermometer while a substance is passing from the solid to the liquid state is called its fusing-point; that indicated during its passage from the liquid to the solid form, its freezing-point; and that indicated dur- ing its passage from the liquid to the gaseous form, its boiling- point. The absorption of heat by a volatilizing liquid is utilized in the arts and in medicine for the production of cold (which is simply the absence of heat), in the manufacture of artificial ice, and in the production of local anaesthesia by the ether-spray. The removal of heat from the body in this way, by the evaporation of perspiration from the surface, is an important factor in the main- tenance of the body temperature at a point consistent with life. When a substance passes from a rarer to a denser form it gives out—liberates—an amount of heat equal to that which it absorbed in its passage in the opposite direction. It is for this reason that, PHYSICAL CHARACTERS OF CHEMICAL INTEREST. 19 while we apply heat to convert a liquid into a vapor, we apply cold (or abstract heat) to reduce a gas to a liquid. As a rule, the thermometrical indication is the same in whichever direction the change of form occurs. Some substances, however, solidify at a temperature slightly different from that at which they fuse. Usually a solid, when sufficiently heated, passes suddenly into the liquid form, and the fusing-point is sharply defined, and easily determined. Some solids, however, like iron and the fats, when heated to the proper degree, are gradually liquefied, first becoming pasty. Such substances have no true fusing-point, as the thermometer passes through several degrees during their liquefaction. Most solids, when heated, are first converted into liquids, and these into gases. There are, however, some exceptions to this rule. Most vapors, when condensed, pass into the liquid form, and this in turn into the solid. Some substances, however, are condensed from the form of vapor directly to that of solid, in which case they are said to sublime. Law of Raoult.—When a substance is dissolved in a liquid the freezing point of the latter is lowered and the amount by which it is lowered varies with the nature and quantity of the dissolved substance. Raoult found that the product obtained by mul- tiplying the amount by which the freezing point of a solution containing a fixed quantity of the dissolved substance (1 gram in 100 c.c.), is lowered by the molecular weight of that substance is nearly constant at 18°.5 C. or at 37° C. (See molecular weight, p. 38.) The following are some of the results of Raoult. D. =de- pression of freezing point in one per cent, solution ; M.W.=molec- ular weight; M. D. = molecular depression. M. w. D. M.D. Hydrogen sulphid 34 0.560 19.2 Sulphurous acid 82 0.232 19.1 Nitrous acid 47 0.404 19.0 Hvdrocvanic acid 27 0.718 19.4 Acet ic acid 60 0.317 19.0 Ammonia 17 1.117 16.9 Methyl alcohol 32 0.541 17.3 Glycerin 92 0.186 17.1 Cane sugar 342 0.054 18.5 Chloral hydrate 165.5 0.114 18.9 Hydrochloric acid 36.5 1.006 36.7 Nitric acid 63 0.568 35.8 Sulphuric acid 98 0.389 38.2 Phosphoric acid 98 0.438 42.9 Sodium hydrate 40 0.905 36.2 Potassium hydrate 56 0.630 35.2 Specific Heat.—Equal volumes of different substances at the same temperature contain different amounts of heat. If two 20 MANUAL OF CHEMISTRY. 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 Avater at 4° (39°.2 F.) be mixed with a litre at 38° (100°.4 F.), the resulting two litres will have a temperature of 21° (69°.8 F.). Mixtures of equal volumes of different substances, at different temperatures, do not liaA'e a temperature Avhich is the mean of the original temperatures of its constituents. A litre of Avater at 4° (39°.2 F.), mixed with a litre of mercury at 38° (100°.4 F.), forms a mixture Avliose temperature is 27° (80°. 6 F.). Mercury and water, therefore, 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° (39°.2 F.) be agitated Avitli a pound of mercury at 70c (158° F.), both liquids will have a temperature of 67° (152°.6 F.). The amount of heat required to raise a kilo of Avater from 0° C. to 1° C. is the unit of heat, and is knoAvn as a calorie. The specific heat of any substance is the amount of heat required to raise one kilo of that substance 1° in temperature, expressed in calories. Thermometers. — Temperatures beloAV and slightly above the boil- ing point of mercury are measured by thermometers. The thermometer is usually a glass tube, having a bulb bloAvn at one extremity and closed at the other. The bulb and part of the tube are fdled with mercury, or with alcohol, AArhose contraction or expansion indicates a fall or rise of temperature. The alcoholic thermometer is used for measur- ing temperatures beloAV the freezing point of mercury (—40°), and the mercurial for temperatures betAveen that point and the boil- ing point of mercury, 360c(680° F.). Mercurial thermometers are also constructed to read still higher temperatures, the boiling point of the mercury being raised by filling the upper part of the tube with nitrogen under pressure. In eATery thermometer there are two fixed points, determined by experiment. The freezing point is fixed by immersing the in- Fig. 14, PHYSICAL CHARACTERS OF CHEMICAL INTEREST. 21 strument in melting ice, and marking the level of the mercury in the tube upon the stem. The boiling point is similarly fixed by suspending the instrument in the steam from boiling water. The instrument is graduated according to one of three scales : the Celsius or Centigrade, the Fahrenheit, and the Reaumur. The freezing point is marked 0° in the Centigrade and R&umur scales, and 32° in the Fahrenheit. The boiling point is marked 100° in the Centigrade, 212° in the Fahrenheit, and 80° in the Reaumur (Fig. 14). The space between the fixed points is di- vided into 100 equal degrees in the Centigrade scale, into 180 in the Fahrenheit, and into 80 in the Reaumur. Five degrees Centi- grade are therefore equal to nine degrees Fahrenheit. To convert a thermometric reading in one scale into its equiva- lent in another the following formula} are used : CvO Centigrade into Fahrenheit, +32=F. o Fahrenheit into Centigrade, ——=C. The Reaumur scale is not used in this country. The Fahren- heit scale is used for unscientific, medical and meteorological purposes, in England and America. The Centigrade scale is used Fig. 15. among all nations for all scientific purposes other than those mentioned, and for all uses on the continent of Europe, except in Germany. _ * Spectroscopy.—A beam of white light, in passing through a prism, is not only refracted, or bent into a different course, but is also dispersed, or divided into the different colors which con- stitute the spectrum (Fig. 15). The red rays, being the least de- 22 MANUAL OF CHEMISTRY. Red. Orange. Yellow. Green. Blue. Indigo. Violet. Fig. 16. PHYSICAL CHARACTERS OF CHEMICAL INTEREST. 23 fleeted are the least refrangible, the violet rays, being the most deflected are the most refrangible. A spectrum is of one of three kinds : 1.) Continuous, consisting of a continuous band of colors : red, orange, yellow, green, blue, cyan-blue, and violet. Such spectra are produced 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 pass- ingthrough a solid, liquid, or gas, capable of absorbing certain rays. Examples of bright-line and absorption spectra are shown in Fig. 16. The spectrum of sun-light belongs to the third class. It is not Fig. 17, continuous, but is crossed by a great number of dark lines, known as Fraunhofer’s lines, the most distinct of which are designated by letters (No. 1, Fig. 16). The spectroscope consists of four essential parts : 1st, the slit, a, Fig. 17 ; a linear opening between two accurately straight and parallel knife-edges. 2d, the colimating lens, 7>;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 parallel to the slit. 4tli, an observing telescope, d. so arranged as to receive the rays as 24 MANUAL OF CHEMISTRY. tliey emerge from the prisms. Besides these parts spectroscopes are usually fitted with some arbitrary graduation, which serves to fix the location of lines or bands observed. In direct vision spectroscopes a compound 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. The micro-spectroscope (Fig. 18) is a direct vision spectroscope used as the eye-piece of a microscope. With it the spectra of very small bodies may be observed. As the spectra produced by different substances are character- ized by the positions of the lines or bands, some means of fixing Fig. 18. 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 deter- PHYSICAL CHARACTERS OF CHEMICAL INTEREST. 25 mined, 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 7004.00 a 7185.00 B 0807.00 C 0502.01 D 5892.12 E 5209.13 b 5172.00 F 4800.72 Gr 4307.25 H, 3908.01 H2 3933.00 The scale of wave-lengths can easily be used with any spectroscope having an arbitrary scale, with the aid of a curve constructed by interpolation. 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 point where the line of its wave-length and that of its position in the arbitrary 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 DO3 to the plane of separation of the two media, is deflected from its course, or refracted. Certain substances 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 peculiarly 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 Nicol’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 extin- guish a ray passing through the former, certain substances are brought between them, light again passes through the analyzer ; and in order again to produce extinction, the analyzer must be rotated upon the axis of the ray to the right or to the left. Sub- stances 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, loevogyrous. The distance through which the analyzer must be turned de- 26 MANUAL OF CIIEMISTKY. pends upon the peculiar power of the optically active substance, the length of the column interposed, the concentration, if in solu- tion, 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 substance, dissolved in one cubic centimetre of a non-active solvent, and examined in a column one decimetre long. The specific rotary power is deter- mined by dissolving a known weight of the substance in a givep volume of solvent, and observing the angle of rotation px*oduced by a column of given length. Then let p = weight in grams of the substance contained 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 r t a [a] =pr 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 [«]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]n for any given substance, we can determine the weight of that substance in a solution by the formula a P ~ |>]d Xl' The polarimeter or saccharoineter is simply a peculiarly con- structed polariscope, used to determine the value of a. Chemical effects of light.—Many chemical combinations and decompositions are much modified by the intensity, and the kind of light to which the reacting substances are exposed. Hydrogen and chlorin gases do not combine, at the ordinary temperature, in the absence of light ; in diffused daylight or gaslight, they unite slowly and quietly ; in direct sunlight, or in the electric light, they unite suddenly and explosively. The salts of silver, used in photography, are not decomposed in the dark, but are rapidly decomposed in the presence of organic matter, when ex- posed to sunlight. The chemical activity of the different colored rays of which the solar spectrum is composed is not the same. Those which are the most refrangible possess the greatest chemical ac- tivity—the greatest actinic power. The visible solar spectrum represents only about one-third of the rays actually emitted from the sun. Two-thirds of the spectrum are invisible as light, PHYSICAL CHARACTERS OE CHEMICAL INTEREST. 27 and are only recognizable by their heating effects, or by chemical decompositions which they provoke. Galvanic Electricity.—If two plates, one of pure zinc, the other of pure copper, be immersed in pure, dilute hydrochloric acid, in such a way that the metals are not in contact with each other, there is no action. But if the two metals be connected, outside of the liquid, by a copper wire, the zinc immediately begins to dissolve, and bubbles of hydrogen gas are collected on, and escape from, the surface of the copper, the action continuing so long as the wire connection is maintained, and ceasing so soon as it is in- terrupted. If a magnetic compass be approached near to the wire, while it is connected with the two plates, the needle will assume a position at right angles to the wire whether the latter be in an east and west position or not. But if the wire be discon- nected from either plate, the needle returns to its normal, north and south, position. While the two plates are connected by the wire, an electrical current is produced by the chemical action be- tween the zinc and hydrochloric acid, and passes through the liquid and through the wire. A similar electrical current is pro- duced whenever two plates, of different substances, which are conductors of electricity, are connected with each other by a con- ducting wire, and the free ends dipped into a liquid which has a more intense chemical action upon one plate than upon the other. The plate upon which the greater chemical action is exerted is known as the negative plate, or negative pole, or anode, and, in most batteries consists of zinc. The other plate is called the col- lecting plate, the positive pole, or the cathode, and usually is made of platinum, carbon or copper. The wires attached to the two plates, as well as any plate, knob or other apparatus in which they terminate are known as the positive and negative electrodes. The current is said to pass from the negative to the positive plate in the battery, and from the positive to the negative in the connecting wire, or apparatus outside the battery. The exciting liquid, the two plates, and the connecting wire, with any con- ducting apparatus that may be interposed in the course of the wire, is called the circuit. The circuit is said to be closed when the conducting circle is complete. It is open, or broken, when it is interrupted at one or more points. Electrolysis.—When a galvanic current of sufficient power passes through a compound liquid, or through a solution of a compound, capable of conducting the current, the compound is decomposed. The decomposition of a compound by this means is called electrolysis, and the substance so decomposed is known as the electrolyte. When compounds are subjected to electrolysis the constituent elements are not discharged throughout the mass, although the 28 MANUAL OF CHEMISTRY. decomposition occurs at all points between the electrodes. In compounds made up of two elements only, 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 sub- jected to electrolysis, pure hydrogen is given off at the negative pole and pure chlorin at the positive pole. In the case of compounds containing more than two elements, a similar 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 intercurrent 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, the liquid surrounding the positive electrode becomes acid in reaction, and gives off oxygen. At the same time the liquid on the negative side becomes alka- line, and gives off a volume of hydrogen double that of the oxygen liberated. In the first place the potassium sulphate, which consists of potassium, sulphur, and oxygen, is decomposed into potassium, which separates at the negative pole ; and sul- phur and oxygen, combined together, which go to the positive pole. The potassium liberated at the negative pole immediately decomposes the surrounding water, forming potash, and liberat- ing hydrogen. The sulphur and oxygen group at the positive pole immediately reacts with water to form sulphuric acid and liberate oxygen. In the electrolysis of chemical compounds the different elements and groups of elements, such as the sulphur and oxygen group 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 therefore known as electro-negative or acidu- lous elements or residues. Those given off at the negative pole, being positively electrified, are known as electro-positive or basy- lous elements or residues. The following are the electrical char- acters of the principal elements and residues : ELECTRO-NEGATIVE OR ACIDULOUS Oxygen, Sulphur, Nitrogen, Chlorin, Iodin, Fluorin, Phosphorus, Selenium, Molybdenum, Tungsten, Boron, Carbon, Antimony, Tellurium, Niobium, Titanium, Arsenic, Chromium, Silicon, Osmium, Residues of acids remaining after the removal of a number of hydrogen atoms equal to the basicity of the acid. PHYSICAL CHARACTERS OF CHEMICAL INTEREST. 29 Nickel, Cobalt, Cerium, Lead, Tin, Bismuth, Uranium, Copper, Electro-positive or Basylous. Glucinium, Yttrium, Aluminium, Zirconium, Manganese, Zinc, Cadmium, Iron, Silver, Mercury, Palladium, Platinum, Rhodium, Iridium, Gold, Alcoholic radicals. Hydrogen, Potassium, Sodium, Lithium, Barium, Strontium, Calcium, Magnesium 30 MANUAL OF CHEMISTRY. CHEMICAL COMBINATION. Elements.—The great majority of the substances existing in and upon the earth may be so decomposed as to yield two or more other substances, distinct in their properties from the sub- stance from whose decomposition they resulted, and from each other. If, for example, sugar be treated with sulphuric acid, it blackens, and a mass of charcoal separates. Upon further exam- ination we find that water has also been produced. From this water we may obtain two gases, differing from each other widely in their properties. Sugar is therefore made up of carbon and the two gases, hydrogen and oxygen ; but it has the properties of sugar, and not those of either of its constituent parts. There is no method known by which carbon, hydrogen, and oxygen can be split up, as sugar is, into other dissimilar substances. An element is a substance which cannot by any known means be split up into other dissimilar bodies. Elements are also called elementary substances or simple sub- stances. The number of well-characterized elements at present known is sixty-nine. Of these, either free, or united with each other in varied proportion, and in different ways, all matter is composed. Laws governing the combination of elements.—The alchemists, Arabian and European, contented themselves in accumulating a store of knowledge of isolated phenomena, without, as far as we know, attempting, in any serious way, to group them in such a manner as to learn the laws governing their occurrence. It was not until the latter part of the last century, 1777, that Wenzel, of Dresden, implied, if he did not distinctly enunciate, what is known as the law of reciprocal proportions. A few years later, Richter, of Berlin, confirming the work of Wenzel, added to it the law of definite proportions, usually called Dalton’s first law. Finally, as the result of his investigations from 1804 to 1808, Dal- ton added the law of multiple proportions, and, reviewing the work of his predecessors, enunciated the results clearly and dis- tinctly. Considering these laws, not in the order of their discovery, but in that of their natural sequence, we have : The Law of Definite Proportions.—The relative weights of elementary substances in a compound are definite and invari- able. If, for example, we analyze water, we find that it is com- posed of eight parts by weight of oxygen for each part by weight of hydrogen, and that this proportion exists in every instance, whatever the source of the water. If, instead of decomposing, or CHEMICAL COMBINATION. 31 analyzing water, we start from its elements, and by synthesis, cause them to unite to form water, we find that, if the mixture be made in the proportion of eight oxygen to one hydrogen by weight, the entire quantity of each gas will be consumed in the formation of water. But if an excess of either have been added to the mixture, that excess will remain after the combination. Compounds are substances made up of two or more elements united with each other in definite proportions. Compounds exhibit properties of their own, which differ from those of the constituent elements to such a degree that the properties of a com- pound can never be deduced from a knowledge of those of the constituent elements. Common salt, for instance, is composed of 39.32 per cent, of the light, bluish-white metal, sodium, and 60.68 per cent, of the greenish-yellow, suffocating gas, chlorin. Compounds made up of two elements only are called binary compounds ; those consisting of three elements, ternary com- pounds ; those containing four elements, quaternary compounds, etc. A mixture is composed of two or more substances, elements or compounds, mingled in any proportion. The characters of a mixture may be predicated from a knowledge of the properties of its constituents. Thus sugar and water may be mixed in any proportion, and the mixture will have the sweetness of the sugar, and will be liquid or solid, according as the liquid or solid ingre- dient predominates in quantity. The Law of Multiple Proportions.—When two elements unite with each other to form more than one compound, the re- sulting compounds contain simple multiple proportions of one element as compared with a constant quantity of the other. Oxygen and nitrogen, for example, unite with each other to form no less than five compounds. Upon analysis we find that in these the two elements bear to each other the following rela- tions by weight: In the first, 14 parts of nitrogen to 8 of oxygen. In the second, 14 parts of nitrogen to 8x2=10 of oxygen. In the third, 14 parts of nitrogen to 8X3=24 of oxygen. In the fourth, 14 parts of nitrogen to 8X4=32 of oxygen. In the fifth, 14 parts of nitrogen to 8X5=40 of oxygen. The Law of Reciprocal Proportions.—The ponderable quantities in which substances unite with the same substance express the relation, or a simple multiple thereof, in which they unite with each other. Or, as Wenzel stated it, “the weights &, b" of several bases which neutralize the same weight a of an acid are the same which will neutralize a constant weight a of another acid; and the weights a, a', a" of different acids which 32 MANUAL OF CHEMISTRY. neutralize the same weight & of a base are the same which will neutralize a constant weight of another base For example : 71 parts of chlorin combine with 40 parts of calcium, and 1G parts of oxygen also combine with 40 parts of calcium, therefore 71 parts of chlorin combine with 10 parts of oxygen, or the two ele- ments combine in the proportion of some simple multiples of 71 and 16. The Atomic Theory.—The laws of Wenzel, Richter, and Dal- ton, given above, are simply generalized statements of certain groups of facts, and, as such, not only admit of no doubt, but are the foundations upon which chemistry as an exact science is based. Dalton, seeking an explanation of the reason of being of these facts, was led to adopt the view held by the Greek philoso- pher, Democritus, that matter was not infinitely divisible. He retained the name atom (arogof = indivisible), given by Democri- tus to the ultimate particles, of which matter was supposed by him to be composed ; but rendered the idea more precise by ascribing to these atoms real magnitude, and a definite weight, and by considering elementary substances as made up of atoms of the same kind, and compounds as consisting of atoms of differ- ent kinds. This hypothesis, the first step toward the atomic theory as en- tertained to-day, afforded a clear explanation of the numerical results stated in the three laws. If hydrogen and oxygen always unite together in the proportion of one of the former to eight of the latter, it is because, said Dalton, the compound consists of an atom of hydrogen, weighing 1. and an atom of oxygen, weighing 8. If, again, in the compounds of nitrogen and oxygen, we have the two elements uniting in the proportion 14 : 8 14 : 8x2 14 : 8X3 14 : 8x4 14 : 8x5, it is because they are sev- erally composed of an atom of nitrogen weighing 14, united to 1, 2, 3, 4, or 5 atoms of oxygen, each weighing 8. Further, that compounds do not exist in which any fraction of 8 oxygen enters, because 8 is the weight of the indivisible atom of oxygen. Dalton’s hypothesis of the existence of atoms as definite quan- tities did not, however, meet with general acceptance. Davy, Wollaston, and others considered the quantities in which Dalton had found the elements to unite with each other, as mere propor- tional numbers or equivalents, as they expressed it, nor is it probable that Dalton’s views would have received any further recognition until such time as they might have been exhumed from some musty tome, had their publication not been closely followed by that of the results of the labors of Humboldt and of Gay Lussac, concerning the volumes in which gases unite with each other. CHEMICAL COMBINATION. In the form of what are known as Gay Lussac’s laws, these results are : First.—There exists a simple relation between the volumes of gases which combine with each other. Second.—There exists a simple relation between the sum of the volumes of the constituent gases, and the volume of the gas formed by their union. For example : 1 volume chlorin unites with 1 volume hydrogen to form 2 volumes hydrochloric acid. 1 volume oxygen unites with 2 volumes hydrogen to form 2 volumes vapor of water. 1 volume nitrogen unites with 3 volumes hydrogen to form 2 volumes ammonia. 1 volume oxygen unites with 1 volume nitrogen to form 2 volumes nitric oxid. 1 volume oxygen unites with 2 volumes nitrogen to form 2 volumes nitrous oxid. Berzelius, basing his views upon these results of Gay Lussac, modified the hypothesis of Dalton and established a distinction between the equivalents and atoms. The composition of water he expressed, in the notation which lie was then introducing, as being H20, and not HO as Dalton’s hypothesis called for. As, however, Berzelius still considered the atom of oxygen as weigh- ing 8, he was obliged also to consider the atoms of hydrogen and of certain other elements as double atoms—a fatal defect in his system, which led to its overthrow, and to the re-establishment of the formula HO for water. It was reserved to Gerhardt to clearly establish the distinction between atom and molecule ; to observe the bearing of the dis- coveries of Avogadro and Ampere upon chemical philosophy; and thus to establish the atomic theory as entertained at present. As a result of his investigations in the domain of organie chemistry, Gerhardt found that, if Dalton’s equivalents be ad- hered to, whenever carbon dioxid or water is liberated by the decomposition of an organic substance, it is invariably in double equivalents, never in single ones. Always 2C02 or 2H0, or some multiple thereof, never C02 or HO. He further found that if the equivalents C=6, H=l, and 0=8 be retained, the formuhe became such that the equivalents of carbon are always divisible by two. In fact, he found the same objections to apply to the notation then in use that had been urged against that of Berzelius. In 1811, Avogadro, from purely physical researches, had been enabled to state the law which is now known by his name, to the effect that equal volumes of all gases, under like conditions of temperature and pressure, contain equal numbers of molecules. This law is also known as the law of Ampere, the French physicist having enunciated it about the same time as, and in- dependently of, his Italian colaborer. In the hands of Gerhardt this law, in connection with those of Gay Lussac, became the foundation of what is sometimes called the “ new chemistry.” Bearing in mind Avogadro’s law, we may 34 MANUAL OF CHEMISTRY. translate the first three combinations given in the table on p. 33 into the following : 1 molecule clilorin unites with 1 molecule hydrogen, to form 2 molecules hydrochloric acid, l molecule oxygen unites with 2 molecules hydrogen, to form 2 molecules vapor of water. 1 molecule nitrogen unites with 3 molecules hydrogen, to form 2 molecules ammonia. But the ponderable quantities in which these combinations take place are: 35.5 chlorin to 1 hydrogen. 16 oxygen to 2 hydrogen. 14 nitrogen to 3 hydrogen. And as single molecules of hydrogen, oxygen, and nitrogen are in these combinations subdivided to form 2 molecules of hydro- chloric acid, water, and ammonia, it follows that these molecules must each contain two equal quantities of hydrogen, oxygen, and nitrogen, less in size than the molecules themselves. And, further, as in these instances each molecule contains two of these smaller quantities, or atoms, the relation between the weights of the molecules must be also the relation between the weights of the atoms, and we may therefore express the combinations thus : 1 atom chlorin weighing 35.5 unites with 1 atom hydrogen weighing 1 ; 1 atom oxygen weighing 16 unites with 2 atoms hydrogen weighing 2 ; 1 atom nitrogen weighing 14 unites with 3 atoms hydrogen weighing 3 ; and consequently, if the atom of hydrogen weighs 1, that of chlorin weighs 35.5, that of oxygen 16, and that of nitrogen 14. Atomic Weight.—The distinction between molecules and atoms may be expressed by the following definitions : A molecule is the smallest quantity of any substance that can exist in the free state. An atom is the smallest quantity of an elementary substance that can enter into a chemical reaction. The molecule is always made up of atoms, upon whose nature, number, and arrangement with regard to each other, the proper- ties of the substance depend. In an elementary substance the atoms composing the molecules are the same in kind, and usu- ally two in number. In compound substances they are dissimi- lar, and vary in quantity from two in a simple compound, like hydrochloric acid, to hundreds or thousands in more complex substances. The word atom can only be used in speaking of an elementary body, and that only while it is passing through a reaction. The term molecule applies indifferently to elements and compounds. The atoms have definite relative weights ; and upon an exact determination of these weights depends the entire science of quantitative analytical chemistry. (See stoichiometry, p. 44.) CHEMICAL COMBINATION. They havre been determined by repeated and careful analyses of perfectly pure compounds of the elements, and express the weight of one atom of the element as compared with the weight of one atom of hydrogen, that being the lightest element known. It is also the weight of a volume of the element, in the form of gas, which would occupy the same volume, under like pressure and temperature, as an amount of hydrogen weighing one. What the absolute weight of an atom of any element may be we do not know, nor would the knowledge be of any service did we pos- sess it. The following table contains a list of the elements at present known, with their atomic weights : ELEMENTS Name. A. | Symbol. is. i Atomic Weight. Name. A. Symbol. B. Atomic Weight. Aluminium... I Al. 27.02 Molybdenum. . Mo. 95.5 Antimony i Sb. 120 ; A ickel....... . Ni. 58 Arsenic ! As. 749 Niobium Nb. 94 Barium Ba. 126.8 ! Nitrogen N 14 044 Bismuth Bi. 200.5 i )smium.... Os 198 5 Boron Bo. 11 Oxygen .... o 16 Bromin Br. 79 952 Palladium Pd. 105.7 Cadmium Cd. 111.8 Phosphorus P. 31 Caesium Cs. 122.0 Platinum Pt. 194.4 Calcium Ca. 40 Potassium K. 39.137 Carbon C. 11.974 ! Rhodium Rh 104.1 Cerium Ce. 141 ! Rubidium Rb 85.3 Chlorin Cl. 85.457 Ruthenium.... Ru. 104.2 Chromium.... Cr. 52.4 Samarium Sm. 150 Cobalt Co. 58.9 Scandium Sc. 44 Copper Cu. 68.2 Selenium Se. 78.8 Davyium Da. 154 Silicon Si. 28 Didymium D. 144.78 Silver Ag. 107.675 Erbium E. 165.9 Sodium Na. 22.998 Fluorin F. 19 Strontium Sr. 87.4 Gallium 68.8 Sulphur S. 31.984 Germanium... Gr. 72.82 Tantalum Ta. 182 Glucinum Gl. 9 Tellurium Te. 128 Gold Au. 196.2 Thallium Tl. 203.7 Hydrogen H. 1 Thorium Th. 233 Indium In. 113.4 Tin Sn. 117.7 lodin I 126.85 Titanium Ti. 49.85 Iridium Ir 192.7 Tungsten W. 183.6 Iron Fe. 55.9 Uranium U. 238.5 Lanthanium.. La. 138.5 Vanadium .. . V. 51.3 Lead Pb. 206.92 Ytterbium Yb. 172.7 Lithium Li. 7 Yttrium ....... Y. 89.8 Magnesium... Mg. 24 Zinc Zn. 64.9 Manganese ... Mn. 54 Zirconium Zr. 89.6 Mercury Hg. 199.7 36 MANUAL OF CHEMISTRY. In some cases the results of analyses are such as would agree with two values as the atomic weight of an element equally well. In this case we can decide which is the correct value by the law of Dulong and Petit. These observers found that while the atomic weights of the elements vary greatly from each other, the specific heats (see p. 19) differ from each other in an opposite manner, and to such an extent that the product obtained by multiplying the two together does not vary much from 6.4. This product is known as the atomic heat. When it is not possible to determine by analysis which of two numbers is the cor- rect atomic weight of an element, that one is selected which, when multiplied by the specific heat, gives a result most nearly approaching 6.4. The atomic heats of boron, carbon, silicon, sulphur, and phos- phorus are subject to great variations, as is shown in the follow- ing table : Boron. Specific Heat. Atomic Heat. Crystallized at — 39.6° 0.1915 2.11 Crystallized at -t- 76.7° 0.2737 3.01 Crystallized at 4- 283.2° 0.3663 3.99 Amorphous... 0.255 2.81 Carbon. Diamond at — 50.5° 0.0635 0.76 Diamond at + 140° 0.2218 2.66 Diamond at + 985° 0.4589 5.51 Graphite at — 50.3° 0.1138 1.37 Graphite at + 138.5° 0.2542 3.05 Graphite at + 977.9° 0.4670 5.60 Wood charcoal 0.2415 2.90 Silicon. Crystallized cit; 39.8° 0.1360 3.81 Crystallized at + 128.7° 0.1964 5.50 Crystallized Hjt + 232.4° 0.2029 5.68 Fused at + 100° 0.175 4.90 Sulphur. Orthorhombic Sit “I- 45° 0.163 5.22 Orthorhombic Sit 99° 0.1776 5.68 Liquid at + 150° 0.234 7.49 Recently fused at + 98° 0.20259 6.48 CHEMICAL COMBINATION. Specific Atomic Phosphorus. Heat. Heat. Yellow at — 78° 0.174 5.39 Yellow at + 36° 0.202 6.26 Liquid at + 100° 0.212 6.57 Amorphous at + 98° 0.170 5.27 It will be observed that, as the temperature of the solid element is increased, the atomic heat more nearly approaches 6.4. It will further be noticed that those elements with which the perturba- tions occur are those which are capable of existing in two or more allotropic forms (see p. 15). 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 “interior work;” it is probable that these perturbations are due to a constant ten- dency of the element to pass from one allotropic condition to an- other. The atomic heats of those elementary gases which have only been liquefied by enormous cold and pressure are tolerably con- stant 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 a gaseous substance or of one which may be converted into vapor, 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. 33), and therefore, 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 hydrogen, while one atom of hydrogen is the unit of comparison, it follows that the specific gravity of a gas compared with hydrogen, multiplied by two, is its molecular weight. For example, the gas acetylene and the liquid benzene each contain 92.31 percent, of carbon, and 7.69 per cent, of hydrogen ; which is equivalent to 24 parts, or two atoms of carbon ; and 2 parts, or two atoms of hydrogen. The sp. gr. of acetylene, re- ferred to hydrogen=2, is 13 ; its molecular weight is, therefore, 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, therefore, 78. and its molecule contains six atoms of carbon and six atoms of hydrogen. When a substance is not capable of being volatilized, its mo- lecular weight may be obtained by determining its percentage 38 MANUAL OF CHEMISTRY. composition by analysis, and selecting that value which is near- est in obedience to the law of Raoult (see p. 19). The vapor densities of comparatively few elements are known : Vapor Atomic Molecular Density. Weight. Weight. Hydrogen 1 2 Oxygen 16 32 Sulphur 32 64 Selenium 79 164 Tellurium 128 260 Chlorin 35.5 35.5 71 Bromin 80 80 160 Iodin 127 254 Phosphorus 31 124 Arsenic 150 75 300 Nitrogen 14 14 28 Potassium 39 39 78 Cadmium 56 112 112 Mercury 100 200 200 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 discrepancies 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, therefore, 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 re- placing atoms of hydrogen. Thus : One atom of chlorin 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 sat- urating 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 0" Trivalent elements, or triads B Quadrivalent elements, or tetrads Civ Quinquivalent elements, or pentads Pv Sexvalent elements, or hexads Wvi Elements of even valence, i. e., those which are bivalent, quad- rivalent, or sexvalent, are sometimes called artiads ; those of un- even valence being designated as perissads. CHEMICAL COMBINATION. 39 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 chlorin and iodin each combine with hydrogen, atom for atom, and in those compounds are consequently univalent, they unite with each other to form two compounds—one contain- ing one atom of iodin and one of chlorin, the other containing one atom of iodin and three of chlorin. Chlorin being univalent, iodin is obviously trivalent in the second of these compounds. Again, phosphorus forms two chlorids, one containing three, the other five atoms of chlorin 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 satu- rated compounds, as phosphorus in the pentachlorid, 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 compounds in which the element has a higher valence than that which might be con- sidered the maximum to-day. The second supposition—notwith- standing the fact that, if we admit the possibility of two dis- tinct valences, we must also admit the possibility of others—is certainly the more tenable and the more natural. In speaking, therefore, 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 element 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 quinqui- valent : platinum is bivalent or quadrivalent. Symbols—Formulae—Equations.—Symbols are conventional ab- breviations 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 element. Thus, wre 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 Chlorin, Cl; Cobalt, Co; Copper, Cu (Cuprum), etc. These symbols do not indicate simply an indeterminate quan- tity, but represent one atom of the corresponding element. 40 MANUAL OF CJIEMISTK1’ 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 chlorin ; C4, four atoms of carbon, etc. What the symbol is to the element, the formula is to the com- pound. By it the number and kind of atoms of which the mole- cule of a substance is made up are indicated. The simplest kind of formula1 are what are known as empirical formulae, which indicate only the kind and number of atoms which form the compound. Thus, HC1 indicates a molecule composed of one atom of hydrogen united with one atom of chlorin ; 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 parentheses ; thus, Al2 (S04)3 means twice A1 and three times S04. For other varieties of formulae, see pp. 50-52. Equations are combinations of formulae and algebraic signs so arranged 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 2KHO+H2S04 = K2S04+2H20 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 sul- phuric 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 com- posed 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 always be the same as that occurring after it. In writing equations they should always be proved by examining whether the half of the equation before the equality sign con- tains the same number of each kind of atom as that after the equality sign. If it do not the equation is incorrect. CHEM ICAL COM BINATION. 41 Acids, Bases, and Salts.—All ternary and quaternary mineral substances have one of three functions. The function of a substance is its chemical character and rela- tionship, and indicates certain general properties, reactions and decompositions which all substances possessing the same function possess or undergo alike. Thus, in mineral chemistry we have acids, bases, and salts ; in organic chemistry alcohols, aldehydes, ketones, ethers, etc. An acid is a compound of an electro-negative element or resi- due with hydrogen; which hydrogen it can part with in exchange for an electro-positive element without formation of a base. 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, therefore, be called an acid. The basicity of an acid is the number of replaceable hydrogen atoms contained in its molecule. A monobasic acid is one containing a single replaceable atom of hydrogen, as nitric acid, HN03; a dibasic acid is one contain- ing two such replaceable atoms, as sulphuric acid, H2SOi ; a tri- basic acid is one containing three replaceable hydrogen atoms, as phosphoric acid, H3PO,. Polybasic acids are such as contain more than one atom of replaceable hydrogen. 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 compound body capable of neutralizing an acid. It is, how- ever, more consistent with modern views to limit the application of the name to such compound substances as are capable of en- tering 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 has been replaced by an electro-positive element or radical; or as compounds of such elements or radicals with one or more groups, OH. Being thus considered as derivable from water, they are also known as basic hydrates. They have the general formula, Mn (OH)?i. They are monatomic, diatomic, triatomic, etc., according as they contain one, two, three, etc., groups oxhydryl (OH). A double decomposition is a reaction in which both of the re- acting compounds are decomposed to form two new compounds. Sulphobases, or hydrosulphids, are compounds in all respects resembling 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 elements for a part or all of the replaceable hydrogen of an acid. They are always formed, therefore, when bases and 42 MANUAL OF CHEMISTRY. acids enter into double decomposition. They are not, as was formerly supposed, formed by the union of a metallic with a non- metallic oxid, but, as stated above, by the substitution 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 SOsCaO, but CaSCh, formed by the interchange of atoms: s 04- H,- (Ca 0 and not s Os- H, o Ca .0 it is, therefore, calcium, sulphate, and not sulphate of lime. The term salt, as used at present, applies to the compounds formed by the substitution of a basylous element for the hydro- gen of any acid ; and indeed, as used by some authors, to the acids themselves, which are considered 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, ?'.e, those the molecules of whose corresponding acids consist of hydrogen, united with one other element, on the one hand ; and the oxysalts, the salts of the oxacids, i.e., those into whose composition oxygen enters, on the other hand. This dis- tinction, however, 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 ele- ment 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 ele- ments corresponding to the hydracids, binary compounds of clilorin, bromin, iodin, and sulphur. There is, on the other hand, a large class of elements the members of which are incapa- ble of forming salts corresponding to the oxacids. No salt of an oxacid with any one of the elements usually classed as metalloids (excepting hydrogen) has been obtained. Haloid salts maybe formed by direct union of their constituent elements ; oxysalts are never so produced. 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 CHEMICAL COMBINATION. 43 acids themselves will probably exist in the solution, provided both acids and salts are soluble. Thus : 2H2S04 4- 3KNOs — KaS04 4- KNOs 4- H2S04 4- 2HNOa 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 : Sulphuric acid. H2S04 + 2C2H30jNa — JNa2S04 + 2C2H302H 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 de- posited : H2S04 4- 20i8H35OaNa — !Na2S04 4- 2Cit-H3502H Sulphuric acid. Sodium stearate. Sodium sulphate. Stearic acid. 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 expelled. Thus, with the application -of heat: H2S04 4- 2NaNOs = Na2S04 4- 2HN03 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 precipitated : Sulphuric acid. Sodium nitrate. Sodium sulphate. Nitric acid. H2S04 + Ba(N03)2 = BaS04 + 2HN03 If to a solution of a salt whose basylous element is insoluble a soluble base is added, capable of forminga soluble salt with the acid, such soluble salt is formed, with precipitation of the insol- uble base : Sulphuric acid. Barium nitrate. Barium sulphate. Nitric acid Cupric sulphate. CuS04 4- 2KHO = K2S04 4- CuH202 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 4- K2S04 = BaS04 4- 2KHO Potassium sulphate. Barium sulphate. Potassium hydrate. Barium hydrate. BaHsOa + Ag2S04 = BaS04 + 2AgHO Silver sulphate. Barium sulphate. Silver hydrate. 44 MANUAL OF CHEMISTRY. When solutions of two salts, the acids of both of which form soluble salts with both bases, are mixed, the resultant liquid con- tains the four salts: 3K2S04 + 3NaNOs = 2K2S04 + Na2S04+ 2KN03 + NaNOs 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 insoluble salt is precipitated : Ba(N03)2 + Na2S04 = BaS04 + 2NaN03 Barium nitrate. Sodium sulphate. Barium sulphate. Sodium nitrate. Stoichiometry (aroixetov = an element; pirpov = a measure)—in its strict sense refers to the law of definite proportions, and to its applications. In a wider sense, the term applies to the mathe- matics of chemistry, to those mathematical calculations by which the quantitative relations of substances acting upon each other, and of the products of such reactions are determined. A chemical reaction can always be expressed by an equation, which, as it represents not only the nature of the materials in- volved, but also the number of molecules of each, is a quantita- tive as well as a qualitative statement. Let it be desired to determine how much sulphuric acid will be required to completely decompose 100 parts of sodium nitrate, and what will be the nature and quantities of the products of the decomposition. First the equation representing the reaction is constructed : Sulphuric acid. H2S04 + 2NaN03 = Na2S04 + 2HN03 Sodium nitrate. Disodic sulphate. Nitric acid. which shows that one molecule of sulphuric acid decomposes two molecules of sodium nitrate, with the formation of one molecule of sodium sulphate and two of nitric acid. The quantities of the different substances are, therefore, represented by their molecular weights, or some multiple thereof, which are in turn obtained by adding together the atomic weights of the constituent atoms : H2S04 + 2NaNOs = Na2S04 + 2HN03 1X2= 2 32X1=32 16X4=64 98 23X1=23 14X1 = 14 16X3=48 85X2=170 23X2=46 32X1=32 16X4=64 142 1X1= 1 14X1=14 16X3=48 63X2=126 CHKM IOAL COMBINATION. 45 Consequently, 98 parts H2S()4 decompose 170 parts NaNOs, and produce 142 parts NaaSCL and 126 parts HN03. To find the result as referred to 100 parts NaN03, we apply the simple pro- portion : 170 : 100 :: 98 : 57.04—57.64=parts H2S04 required. 170 : 100 :: 142 : 83.53—83.53= “ Na2S(34 produced. i70 : 100 :: 120 : 74.11—74.11= “ HN03 As in writing equations (see p. 40), the work should always be proved by adding together the quantities on each side of the equality sign, which should equal each other : 98+170=268= 142+126=268 or 57.64+100=157.64=88.53+ 74.11=157.64. In determining quantities as above, regard must be had to the purity of the reagents used, and, if they be crystallized, to the amount of water of crystallization (see p. 15) they contain. Let it be desired to determine how much crystallized cupric sulphate can be obtained from 100 parts of sulphuric acid of 92# strength. As cupric sulphate crystallizes with five molecules of water of crystallization the reaction occurs according to the equation : Sulphuric acid. H2S04 + CuO + 4HaO = CuS045Aq. Cupric oxiil. Water Cupric sulphate. 63 16 79 1X2= 2 16X1=16 18X4=72 63X1=63 32X1=32 16x4=64 18X5=90 249 1X2= 2 32X1=32 16X4=64 98 98 + 79 + 72 = 249. 98 parts of 100# H2S04 will produce, therefore, 249 parts of crys- tallized cupric sulphate. But as the acid liquid used contains only 92 parts of true H2S04 in 100; 100 parts of such acid will yield 233.75 parts of crystallized sulphate, for 98 : 92 : : 249 : 233.75. In gravimetric quantitative analysis the substance whose quan- tity is to be determined is converted into an insoluble compound, which is then purified, dried, and weighed (see Part III.), and from this weight the desired result is calculated. Let the problem be to determine what percentage of silver is contained in a silver coin. Advantage is taken of the formation of the insoluble silver chlorid. A piece of the coin is then chipped off and weighed : Weight of coin used = 2.5643 grams. The chip is then dissolved in nitric acid, forming a solution of silver nitrate. From this solution the silver is precipitated as chlorid, by the addition of hydrochloric acid, according to the equation : 46 MANUAL OF CHEMISTRY. AgNOs + HC1 = AgCl + HNCh Silver nitrate. Hydrochloric acid. Silver chlorid. Nitric acid. 108X1 = 108 14X1= 14 16X3=_48 170 1 35.5 736775 108 35.5 14375 lXl= 1 14X1=14 16X3—48 63 170 + 36.5 = 206.5 = 143.5 + 63. The silver chlorid is collected, dried, and weighed : Weight of coin used 2.5643 grams. Weight of AgCl obtained 3.0665 “ as 143.5 grams AgCl contain 108 grams Ag—143.5 :108 : : 3.0665 : 2.3078—2.5643 grams of the coin contain 2.3078 grams of silver, or 90#—2.5643 :100 : : 2.3078 : 8. Nomenclature.—The names * of the elements are mostly of Greek derivation, and have their origin in some prominent prop- erty of the substance. Thus, phosphorus, <£w?, light, and epeiv, to hear. Some are of Latin origin, as silicon, from silex, flint ; some of Gothic origin, as iron, from iarn; and others are de- rived 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 in 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 ele- ments. So long as the number of compounds with which the chemist had to deal remained small, the xise 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 later days, however, when the number of compounds known to exist, or Avhose existence is shown by approved theory to be possible, is practically infinite, some systematic method of nomenclature has become absolutely necessary. The principle of the system of nomenclature at present used is that the name shall convey 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 tlie more electro-negative, in which the termination id has been substituted for the termination, in, on, ogen, ygen, ♦For rules governing orthography and pronunciation of chemical terms see Appendix A. CHEMICAL COMBINATION. 47 orus, ium, and ur. For example : the compound of potassium and chlorin is called potassium chlomZ, that of potassium and oxygen, potassium oxid, that of potassium and phosphorus, po- tassium phosphid. 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 therefore deserving of ex- ceptional prominence. Such are ammonia, NH3; water, H20. When, as frequently happens, two elements unite with each other to form more than one compound, these are usually dis- tinguished from each other by prefixing to the name of the ele- ment varying in amount the Greek numeral corresponding to the number of atoms of that element, 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 : N20 = Nitrogen mouoxid. NO (=N202)=Nitrogen eZzoxid. NaOa =Nitrogen trioxid. N03 (=N304) = Nitrogen tetr oxid. N205 =Nitrogen pentoxid. 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-negative element, and in ic in that containing the greater proportion ; thus : S02=Sulphurous oxid. S03 = Sulphuric oxid. HgaCla (2Hg : 2C1) = Mercurous chlorid. HgCl2 (2Hg : 4C1)=Mercuric chlorid. This method, although used to a certain extent in speaking of compounds composed of two elements of Class II. (see p. 54), is used chiefiy in speaking 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 ; HNOa = Nitroits acid. HNOa = Nitric acid. 48 M A NTT A b OF CHEMISTKY. If there be more than two acids, formed in regular series, the least oxidized 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: HCIO = Hypoch]orous acid. HG102 — Chloro?/,S' acid. HCIO3 = Chloric acid. HCIO4 = 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 dropping 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 : HN02 KNCh Nitrows acid. HNO3 Potassium nitrite. KNOs Nitric acid. Potassium nitrate. Hypochlorows acid. HCIO Potassium hypochlorite KCIO Acids whose molecules contain more than one atom of replace- able hydrogen are capable of forming more than one salt with electro-positive elements, or radicals, whose valence is less than the basicity of the acid. Ordinary phosphoric acid, for instance, con- tains in each molecule three atoms of basic hydrogen, and conse- quently 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 metal. To distinguish these the Greek pre- fixes mono, di, and tri are used, the termination ium of the name of the metal being changed to ic, thus : H2KP04 = Monopotnssic phosphate. HK2P04 = Dipotassic phosphate. K3PO4 = TVipotassie phosphate. The first is also called clihydropoteissic phosphate, and the second, hydrodipot&ssic 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 dis- placed 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 CHEMICAL COMBINATION. 49 containing the less proportion of the electro negative group, and the suffix ic in those containing the greater proportion, e.g. : (CuuhSCL (1S04 : 4Cu) = Cuprous sulphate. Cu2S04 (2SO4 : 4Cu) = Cupric sulphate. FeS04 (2SO4 : 2Fe) = Ferrous sulphate. (Fe2)(S04)3 (3S(J>4 : 2Fe) = Ferric sulphate. The names, basic salts, subsalts, and oxysalts have been ap- plied indifferently to salts, such as the lead subacetates, which are compounds containing the normal acetate and the hydrate or oxid of lead ; and to salts such as the so-called bismuth subni- trate, 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 substitu- tion of different elements or radicals for two or more atoms of replaceable hydrogen of the acid, such as ammonio-magnesian phosphate, PChMg" (NH4)'. Radicals.—Many compounds contain groups of atoms which pass from one compound to another, and, in many reactions, be- have like elementary atoms. Such groups are called radicals, or compound radicals. Marsh gas has the composition CH4. By acting 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 com- pounds, such‘as: (CHS)C1; (CH.)OH ; (CH,)„0 ; C2H302 (CH,). Marsh gas, therefore, consists of the radical (CH3) combined with an atom of hydrogen : (CH3) H. It is especially among the compounds of carbon that the exist- ence of radicals comes into prominent notice. They, however, occur in inorganic substances also. Thus the nitric acid mole- cule consists of the radical N02, combined with the group OH. Like the elements, the radicals possess different valences, de- pending 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 phos- phoric acid is trivalent, because two of the five valences of the phosphorus atom are satisfied by the two valences of the biva- lent 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 termi- nate in yl or in gen ; thus : (CH3) = methyl; (CN) = cyanogen. The terms radical and residue, although sometimes used as synonyms, are not such in speaking of electrical decompositions (see p. 27). Thus the radical of sulphuric acid is S08; but when 50 MANUAL OF CHEMISTRY. sulphuric acid is electrolyzed it is decomposed into hydrogen and the residue S04. Composition and Constitution.—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. There are, for instance, two substances, each having the empirical formula C2H402, one of which is a strong acid, the other a neu- tral ether. As the molecule of each contains the same number and kind of atoms, the differences in their properties must be due to differences in the manner in which the atoms are linked to- gether. The composition of a compound is the number and kind of atoms contained 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. In the system of typical formulae all substances are considered as being so constituted that their rational formulae may be re- ferred 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 The water The ammonia type. type. type. Hi Hi S}o H) H -N H i H2 ) £}<>■ H2 ) h2 f h2 *n3 etc., etc., h3 ) etc., it being considered that the formula of any substance of known constitution can be indicated by substituting the proper ele- ment, or radical, for one or more of the atoms of the type, thus : Cl) H ) (CaH5') ) 0 H (U (C2H.)' ) H [■ N H Cl2 ) Ca \ (CO)" ) h2 [ n2 h2 ) Hydrochloric acid. Alcohol. Ethylamin. Calcium chlorid. Sulphuric acid. Urea. Typical formulae 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 C2H402, we find on examination that one contains the group (CH3)', while the other contains the CHEMICAL COMBINATION. 51 group (CaHsO)'. The difference in their constitution at once becomes apparent in their typical formulae, !- O and ((J H O) ) v a 3 H -■ O, indicating differences 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 sub- stance, on the otner 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 : | q Although typical formula; have been and still are of great ser- vice, many cases arise, especially in treating of the more complex organic substances, 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 ordinary lactic acid, we find its composition to be C3Ht)03, which, expressed typically, would be (C3H4O) ) 04 +7Aq. Water decomposes the clilorids of the second class of elements (those of carbon only at high temperatures and under pressure); while the chlorids of the elements of the third and fourth classes are either insoluble, or soluble without decomposition. Natural Waters.—Water, as it occurs in nature, ahvays con- tains solid and gaseous matter in solution and frequently solids in suspension. Natural Avaters 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, snoAv- and ice-water, spring-water (fresh), river-water, lake-water, and Avell-Avater. To the second class belong stagnant waters, sea- Avater, and the waters of mineral springs. Rain-water is usually the purest of natural Avaters, so far as dissoWed solids are concerned, containing ATerv small quantities of the chlorids, sulphates, and nitrates of sodium and ammo- nium. OAving to the large surface exposed during condensa- tion, rain-water contains relatively large quantities of dissolved gases—oxygen, nitrogen, and carbon dioxid ; and sometimes hydrogen sulphid and sulphur dioxid. The absence of carbon- ates and the presence of nitrates and oxygen render rain-water particularly prone to dissolve lead, when in contact with that metal. In summer, rain-water is liable to become charged Avith vegetable organic matter suspended in the atmosphere. Ice-water contains very small quantities of dissolved solids or WATER. gases, which, during freezing, remain in great part in the un- frozen water. Suspended 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 of the earth’s crust (in which it may also have been sub- jected 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 percolated, the duration of con- tact, and the pressure to which it was subject during such con- tact. Spring-waters from igneous rocks and from the older sedi- mentary formations 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 40 parts in 100,000 of solid matter; provided that a large proportion of the solid matter does not consist of salts having a medicinal action, and that sulphurous gases and sulphids are absent. Artesian wells are artificial springs, produced by boring in a I >w-lying district, until a pervious layer, between two imper- vious 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 streanrflowing sluggishly through rich alluvial land is un- aerated, and rich in dissolved and suspended solids. The amount of dissolved solids in river-water increases with the distance from its source. The chief sources of pollution of river-water are by the dis- charge 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 current, they become to a certain extent purified from organic contamination. Well-water may be very good or very bad. If the well be simply a reservoir 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 water which has percolated through the thin layer of earth corresponding to the depth of the 68 MANUAL OF CHEMISTKY. well, and is consequently warm, unaerated and charged with organic impurity. Such water is sometimes called “ ground water.” Wells dug near dwellings are very liable to become charged with the worst of contaminations, animal excreta, by their filtra- tion 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 purposes 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 precip- itate. 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 possess 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 pota- ble waters varies from 5 to 40 in 100,000 ; and a water containing more than the latter quantity is to be condemned on that account alone. To determine the quantity of total solids 500 c.c. of the filtered water are evaporated to dryness in a previously weighed plati- num dish, over the water-bath. The dish with the contained dry residue is cooled in a desiccator and again weighed. The in- crease in weight, multiplied by 200, gives the total solids in parts per 100,000. Hardness.—The greater part of the solid matter dissolved in natural fresh 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 chlorid, 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 presence of the carbonate it is temporary, if due to the sulphate it is permanent. Calcium carbonate is almost insol- uble 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 50 in 100,000. 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 determine their quantity approximately, the result being the degree of hardness. WATER. For this purpose a solution of soap of known strength is re- quired. 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. 0.940). 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 chlorid in a litre of water, are diluted with GO 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 concen- trated 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 addi- tion of soap solution 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 indicated by the number of c.c. of soap solution added, minus one. If more than 1G 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. Chlorids.—The presence of the clilorids 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 or- ganic impurity, a determination of the amount of chlorin affords a ready method of indicating the probable source of the organic contamination. As vegetable organic matter brings with it but small quantities of chlorids, while animal contaminations are rich in those compounds, the presence of a large amount of chlorin serves to indicate that organic impurity is of animal origin. In- deed. when time presses, as during an epidemic, it is best to rely upon determinations of chlorin, and condemn all waters contain- ing more than 1.5 in 100,000 of that element. For the determination of chlorin two solutions are required : a solution of silver nitrate containing 4.79 grams per litre ; a strong solution of potassium chromate. One hundred c.c. 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 solution 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 chlorin per litre. Organic Matter.—The most serious of the probable contamina- tions 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 chlorin is greater 70 MANUAL OF CHEMISTRY. than usual, the water has been contaminated 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 organic matter in natural waters there is, unfortunately, none which is easy of application and at the same time reliable. That which yields 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 permanga- nate in a litre of water. The solution is boiled down to about 725 c.c., cooled, and brought to its original bulk by the addition of boiled distilled water, b. Nessler's reagent. 85 grams of potassium iodid and 18 grams of mercuric clilorid are dissolved in 800 c.c. of water by the aid of heat and agitation. A cold, saturated solution of meeuric clilorid is then added, drop by drop, until the red pre- cipitate which is formed is no longer redissolved on agitation ; 100 grams of potassium hydrate are then dissolved in the liquid, to which a slight excess of mercuric clilorid solution is finally added, and the bulk of the whole made up to a litre with water. Hie solution is allowed to stand, decanted, and preserved in com- pletely filled, well-stoppered bottles, c. Standard solutions of ammonia. The stronger of these is made by dissolving 3.15 grams of ammonium clilorid in a litre of water, dlie 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 determinations, 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’g 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 hold- ing 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 inade 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 dis- tillate 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 ammonia contained in the half-litre of water. When 200 c.c. have distilled over, all the free ammonia lias been removed, and it now remains to decompose 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, stoppered, and again heated. The distillate is now collected in separate portions of 50 c.c. each, in glass cylinders, until 3 such portions have been collected. These are then separately Ness- lerized as follows : 2 c.c. of the Nessler reagent are added to the WATER. 71 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 cylinder 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 Kessler reagent. This cylinder, and that con- taining the 50 c.c. of Nesslerized distillate, are then placed side by side on 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 moreorlessof the standard solution, as the first compai*i- son-cylinder was lighter or darker than the distillate. When the proper similarity of shades has been attained, the number of cubic centimetres of the standard solution used is determined 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 Vith the three portions of 50 c.c. each, distilled after the addition of the permanganate solution. If, for example, it required 1 c.c. of standard solution in Nessler- izing 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 result 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 j)ure, even if it contains much free ammonia and clilorids. If it contain 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 suspicion ; 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 albumi- noid ammonia is to be looked upon with suspicion. Nitrates and Nitrites—Are present in rain-water in quantities less than 2 parts in 100,000, calculated as N203. When the amount exceeds this, these salts are considered as indicating previous contamination by organic matter which has been oxidized and whose nitrogen has been to some extent converted into nitrites and nitrates. To determine the amount of nitrous acid the following solutions are used : 1.) Dilute sulphuric acid 1:3; 2.) A solution containing 5 grams of metaphenylendiamin and sufficient sulphuric acid to 72 MANUAL OF CIIEMISTKY. form an acid reaction in -1 litre of H20 ; 3.) A solution made by dissolving 0.400 gram pure, dry silver nitrite in hot water, adding pure sodium clilorid so long as a precipitate is formed, diluting with HjO to 1 litre, after cooling and Avithout filtration. 100 c.c. of the clear liquid are then diluted to 1 litre. 1 c.c. of this solution contains 0.01 mgr. N2O3. To make the determination 100 c.c. of the water are placed in a glass cylinder and 1 c.c. each of solutions 1 and 2 added. Three other cylinders are at the same time prepared, by diluting from 0.3 to 2.5 c.c. of solution 3 to 100 c.c. with pure H20, and adding to each 1 c.c. each of solutions 1 and 2. The shade of color of the water-cylinder is then compared with that of the others, as described above in Nesslerizing. The amount of N203 in the water is equal to that in the comparison-cylinder having the same shade. 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. Lead is not dissolved by water as lead, but only after conversion into an oxid ; therefore any condition favoring the oxidation of the metal favors its solution. The presence 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 alternately acted upon by it and by the air. On the other hand, waters containing carbonates or free carbonic acid may be left in contact with lead with comparative impunity, owing to the formation of a protective coating of the insoluble carbonate of lead on the surface of the metal. This does not apply, however, to water charged with a large excess of carbon dioxid 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 carbonates, and compara- tively small quantities of carbon dioxid. Obviously, therefore, 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 WATER. 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 dissolving lead, such as to render its contact with surfaces of that metal dangerous if prolonged beyond a short time. To test for the presence of poisonous metals, solution of am- monium sulpliydrate is added to the water, contained in a porce- lain capsule. If a dark color be produced, which is not discharged on addition of hydrochloric acid, the water is contaminated with lead or copper. For quantitative determinations, solutions containing known quantities of the poisonous metals are used : for iron 4.9(5 grams of ferrous sulphate in a litre of water ; for copper 3.93 grams of cupric sulphate to the litre ; and for lead 1.06 gram of lead ace- tate 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 cap- sules, to each of which some ammonium sulphydrate is then added. The appropriate standard 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 suspended mechanically in the water, which deposits them when it remains at rest, or they have been in solution, and are deposited by becoming insoluble as the water is deprived of carbon dioxid by exposure to air and by relief from pressure. The suspended particles should be collected by subsidence in a conical glass, anti should be 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. Bacteriological Examination of Water.—In recent years much attention has been given to the examination of natural waters by bacteriological methods, plate cultures on gelatin, cultures in blood serum and on potatoes, and experiments on animals. Although in some instances pathogenic bacteria have been found in water, and although in tlie future valuable results will proba- bly be attained by these methods, the chief reliance in deter- mining the quality of a drinking-water is still to be placed upon the older chemical processes. Purification of Water.—The artificial means of rendering a more or less contaminated water fit for use are of five kinds : 1. Distil- 74 MANUAL OF CHEMISTRY. lation ; 2. Subsidence ; 3. Filtration ; 4. Precipitation ; 5. Boil- ing. The method of distillation is used in the laboratory when a very pure water is desired, and also at sea. 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 0.03 gram each of calcic bicarbonate and sodium chlorid 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. 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 separated, 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 or- ganic matters, whether in solution or in suspension. In the filtra- tion 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 oxida- tion of nitrogenized organic matter in the former case. Precipitation processes are only adapted to hard waters, and are designed to separate the excess of calcium salt, and at the same time a considerable quantity of organic matter, which is mechanically carried down with the precipitate. The method usually followed consists in the addition of lime (in the form of lime-water), in just sufficient quantity to neutralize the excess of carbon dioxid present in the water. The added lime, together with the ealcmm salt naturally present in the water, is then pre- cipitated, except that small portion of calcium carbonate which the water, freed from carbon dioxid, 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 soften- ing of temporarily hard waters, and for the destruction of organ- AVATEK. ized impurities, for which latter purpose it should never be neg- lected during outbreaks of cholera and typhoid, if, indeed, water be drank at all at such times. Natural Purification of Water.—The water of brooks, rivers, and lakes which have been contaminated by sewage and other organic impurity becomes gradually purified by' natural proc- esses. Suspended particles are deposited upon the bottom and sides of the stream, more or less rapidly, according to their grav- ity' and the rapidity of the current. The bicarbonates of cal- cium, magnesium, and iron gradually lose carbon dioxid, and are precipitated as carbonates, which mechanically carry down dis- solved as well as suspended impurities. The fermentations, oxi- dations, and reductions to which organic matters are subject bring about their gradual mineralization and the conversion of ammonia into nitrates. The processes of nutrition of aquatic plant life absorb dissolved organic impurity, as well as the prod- ucts of decomposition of nitrogenized substances. This natural purification proceeds the more rapidly the more contact with air is favored. 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° F.). The composition of mineral waters varies greatly, according to the nature of the strata or veins through which the water passes, and to the conditions of pressure and previous composition under which it is in contact with these deposits. The substances almost universally present in mineral waters are: oxygen, nitrogen, carbon dioxid ; sodium carbonate, bicar- bonate, sulphate and chlorid ; and calcium bicarbonate. Of sub- stances occasionally present the most important are : sulphydric acid ; sulphids of sodium, iron, and magnesium ; bromids and iodids of sodium and magnesium ; calcium and magnesium chlo- rals ; carbonate, bicarbonate, sulphate, peroxid, and crenate of iron ; silicates of sodium, calcium, magnesium, and iron ; alu- minium salts ; salts of lithium, caesium, and rubidium; free sul- phuric, silicic, arsenic, and boric acids ; and ammoniacal salts. Although a sharply defined classification of mineral waters is not possible, one which is useful, if not accurate, may' be made, based upon the predominance of some constituent, or constit- uents, which impart to the water a well-defined therapeutic value. A classification which has been generally adopted includes five classes : 1. Acidulous waters; whose value depends upon dissolved car- bonic acid. They contain but small quantities of solids, princi- pally the bicarbonates of sodium and calcium and sodium chlorid. 76 MANUAL OF CHEMISTRY. 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 dioxid by boiling. III. Chalybeate waters; which contain salts of iron in greater proportion than 4 parts in 100,000. They contain ferrous bicar- bonate, sulphate, crenate, and apocrenate, calcium carbonate, sulphates of potassium, sodium, calcium, magnesium, and alu- minium, notable quantities of sodium chlorid, and frequently small amounts of arsenic. 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 dioxid, and formation of ferrous carbonate. IV. Saline waters ; which contain neutral salts inconsiderable quantity. The nature of the salts which they contain is so diverse that the group may wrell be subdivided : a. Chlorin waters; which contain large quantities of sodium chlorid, accompanied by less amounts of the chlorids of potas- sium, calcium, and magnesium. Some are so rich in sodium chlorid 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 300 parts in 100,000 of sodium chlorid belongs to this class, provided it do not contain substances more active in their medicinal action in such proportion as to warrant its classification elsewhere. Waters containing more than 1,500 parts in 100,000 are too concentrated for internal administration. /?. Sulphate waters are actively purgative from the presence of considerable 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 sulphates of magnesium and calcium is as high as 3,000 parts in 100,000 to 2,000 parts in 100,000 of sodium sulphate. They vary much in concentration ; from 500 to nearly 6,000 parts of total solids in 100,000. They have a salty, bitter taste, and vary much in temperature. ■y. Bromin and iodin waters are such as contain the bromids or iodids of potassium, sodium, or magnesium in sufficient quantity to communicate to them the medicinal properties of those salts. V. Sulphurous waters ; which hold hydrogen sulphid or metal- lic sulphids in solution. They have a disagreeable odor and are usually warm. They contain 20 to 400 parts in 100,000 of total solids. 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 (24 to 3 quarts) per HYDliOGEN DIOXID. diem. The greater the elimination and the drier the nature of the food the greater is the amount of H 20 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 perspiration 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 l’elative proportion of solids and 1I20, but is influenced by the nature of the solids. The blood, although liquid in the ordinary sense of the term, contains a less proportional amount of JH20 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 propor- tion of H20 to solids than does that liquid. Water is discharged by the kidneys, intestine, skin, and pul- monary 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 Dioxid H20n—Molecular weight — 34—Sp. gr. = 1.455—Discovered by Thenard in 1818. Exists naturally in very minute quantity in rain-water, in air, and in the saliva. This substance may be obtained in a state of purity by accu- rately following the process of Thenard. It may also be obtained, mixed with a large quantity of H20, by passing a rapid current of carbon dioxid through H20 holding hydrate of barium dioxid in suspension —Ba03H2 + C02 = BaC03 -f- H202. 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. It is prepared industrially of 10-12 volume strength by gradu- ally adding barium peroxid to dilute hydrofluoric acid solution, the mixture being maintained at a low temperature and con- stantly agitated. The pure substance is a colorless, syrupy liquid, which, when poured into H20, sinks under it before mixing. It has a disagree- able, metallic taste, somewhat resembling that of tartar emetic. When taken into the mouth it produces a tingling sensation, in- creases 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 tempex-ature, is gradually decomposed. At 20’ (68’ F.) the decomposition takes Hydrogen peroxid—Oxygenated water. MANUAL OF CHEMISTRY. place more quickly, and at 100° (212° F.) rapidly and with effer- vescence. The dilute substance, however, is comparatively stable, and may be boiled and even distilled without suffering decompo- sition. Yet it is liable to explosive decomposition when exposed to summer temperature in closed vessels. Hydrogen* peroxid acts both as a reducing and an oxidizing agent. Arsenic, sulphids, and sulphur dioxid are oxidized by it at the expense of half its oxygen. When it is brought in contact with silver oxid both substances are violently decomposed, water and elementary silver remaining. By certain substances, such as gold, platinum, and charcoal in a state of fine division, fibrin, or manganese dioxid, it is decomposed with evolution of oxygen ; the decomposing agent remaining unchanged. The pure substance, when decomposed, yields 475 times its vol- ume 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. It is an energetic disinfectant and antiseptic, and is extensively used in surgery. Analytical Characters.—1. To a solution of starch a few drops of cadmium iodid solution are added, then a small quantity of the fluid to lie tested, and, finally, a drop of a solution of ferrous sulphate. A blue color is produced in the presence of hydrogen peroxid, even if the solution contain only 0.05 milligram per litre. 2. Add freshly prepared tincture of guaiacum and a few drops of a cold infusion of malt. A blue color—1 in 2,000,000. 3. Add the liquid to be tested to mixed solutions of ferric chlorid and potassium ferricyanid (which should have no blue tinge). A blue color—1 in 10,000,000. 4. Add to 6 c.c. of the liquid sulphuric acid, iodid of zinc, starch-paste, two drops of a two per cent, solution of cupric sulphate, and a little one-half per cent, solution of ferrous sul- phate, in the order named. A blue color. 5. Add a trace of acetic acid, some a naphtliylamin and solid sodium chlorid. After a short time a blue or blue-violet color and, after some hours, a flocculent ppt. of the same color. Atmospheric Hydrogen Dioxid.—It has been claimed that atmospheric air, rain-water, snow, and hoar-frost constantly contain small quantities of hydrogen peroxid ; the amount in rain-water varying from 0.0008 to 0.05 part in 100,000. The most recent experiments bearing upon the supposed presence of ozone and hydrogen peroxid in atmospheric air seem, however, to justify the belief that those substances, if present in air at all, are not met with in the amounts and with the constancy that have been claimed. According to this later view, the appear- ances from which the presence of ozone and hydrogen peroxid has been inferred are not caused by those substances, but by nitrous acid and the oxids of nitrogen. FLUORIN. 70 CLASS II.—ACIDULOUS ELEMENTS. Elements all of whose Hydrates are Acids, and which do not form Salts with the Oxacids. I. CHLORIN GROUP. Fluoric. Chlorin. Bromin. Iodin. 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 (fluorin forms no hydrate). The first two are gases, the third liquid, the fourth solid at ordi- temperatures. They are known as the halogens. The relations of their compounds to each other are shown in the fol- lowing table : HF HC1 HBr HI ChO CI2O3 ChCh I2O4 HCIO HBrO HIO HCICh HIOa HCIO* HBr03 HI03 HCICh HBrCh HIO4 Hydro-ic acid. Monoxid. Trioxid. Tetroxid. . Hypo- ous acid. -ous acid. -ic acid. Per-ic acid. FLUORIN. Symbol = F—Atomic weight = 19—Sp. gr. 1.265 A (calculated = 1.316)—Discovered by Sir H. Davy in 1812. Fluorin has been isolated by the electrolysis of HF at —23° (—93.4 F.). It is a gas, colorless in thin layers, greenish-yellow in layers 50 cent, thick. It decomposes H20, with formation of HF and ozone. In it Si, Bo, As, Sb, S, and I fire spontaneously. With H it detonates violently, even in the dark. It attacks organic substances vio- lently. The apparatus in which it is liberated must be made of platinum and fluor-spar. It forms compounds with all other elements except oxygen. Hydrogen Fluorid—Hydrofluoric acid = HF—Molecular weight = 20. Hydrofluoric acid is obtained by the action of an excess of sulphuric acid upon fluor-spar or upon barium fluorid, with the aid of gentle heat : CaF2+ H2SOj = CaSCh-|-2 HF. Ifasolution be desired, the operation is conducted in a platinum or lead re- tort. 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 corro- 80 MANUAL OF CHEMISTRY. sive, and having a penetrating odor. Great care must be exer- cised that neither the solution nor the gas come in contact with the skin, as they produce painful ulcers which heal with diffi- culty, and also constitutional symptoms which may last for days. The inhalation of air containing very small quantities of HF has caused permanent loss of voice and, in two cases, death. 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. 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 coat- ing of wax. The presence of fluorin in a compound is detected by reducing the substance to powder, moistening it with sulphuric acid in a platinum crucible, 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 fluorid. Symbol = Cl—Atomic weight=‘S5.5—Molecular weight — 71—Sp. gr. = 2.4502 A—One litre weighs 3.17 grams—100 cubic inches weigh 70.3 grains—Name derived from = yellowish-green— Discovered by Scheele in 1774. Occurrence.—Only in combination, most abundantly in sodium chlorid. Preparation.—(1.) By heating together manganese dioxid and hydrochloric acid (Scheele). The reaction takes place in two stages. Manganic chlorid is first formed according to the equa- tion: MnOa -f- 4HC1 = MnCh -f- 2H20 ; and is subsequently de- composed into manganous chlorid and chlorin : MnCl4 = MnCU + Cl,. CHLORIN. This and similar operations are usually conducted in an appa- ratus such as that shown in Fig. 23. The earthenware vessel A (which on a small scale may be replaced by a glass flask) is two- tliirds tilled with lumps of manganese dioxid of the size of hazel- nuts, and adjusted in the water-batli; 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 chlorid 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 chlorid. wash the remaining oxid with water and begin anew. A kilo, of oxid yields 257.5 litres of Cl. CHLOKIN. 81 (2.) By the action of manganese dioxid upon hydrochloric acid in the presence of sulphuric acid, manganous sulphate being also formed : Mii02 + 2HC1+ H2S04 = MnSCh-f- 2H20-(- Cl2. The same quantity of chlorin 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 dioxid and sodium chlorid, with three parts of sulphuric acid. Hydro- chloric acid and sodium sulphate are first formed : H2S04 + 2NaCl = Na2S04 + 2HC1; and the acid is immediately decom- posed by either of the reactions indicated in (1) and (2), according as sulphuric acid is or is not present in excess. (4.) By the action of potassium dichromate upon hydrochloric Fig. S3. acid; potassium and chromic chloride being also formed: K2Cr207 + 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 yielding 22.5 litres of Cl. (5.) A convenient method of obtaining chlorin on a laboratory scale is by the use of “ chlorin cubes.” These are made by press- ing together 1 part of plaster of Paris and 4 parts of chloral of lime (q. v.), cutting into small cubes and drying. The cubes are used in one of the forms of constant apparatus (Figs. 10, 20, 21), with dilute hydrochloric acid, Cl being evolved at the ordinary temperature. When a slow evolution of Cl, extending over a considerable MANUAL OF CHEMISTRY. period of time, is desired, as for ordinary disinfection, moistened chlorid of lime is exposed to the air, the calcium hypochlorite being decomposed by the atmospheric carbon dioxid. If a more rapid evolution of gas be desired, the chlorid of lime is moist ened with dilute hydrochloric acid in place of with water. (6.) By the action of potassium chlorate upon hydrochloric acid Cl is liberated, slowly at the ordinary temperature, more rapidly at the temperature of the water-bath : 2KCIO3 + 4HC1 = Cl* + C1204 + 2KC1 + 2H20. Potassium chlorate. Hydrochloric acid. Chlorin Chlorin tetroxid. Potassium chlorid. Water. Properties.—Physical.—A greenish-yellow gas, at the ordinary temperature 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 vol- umes of the solvent, it must be collected by displacement of air, as shown in Fig. 23. A saturated aqueous solution of Cl is known to chemists as chlorin water, and in pharmacy as aqua chlori (Z7. $.), Liquor chlori (Br.). It should bleach, but not redden, litmus paper. Under a pressure of G atmospheres at 0° (32° F.), or atmospheres at 12° (53°.6 F.), Cl becomes an oily, yellow liquid, of sp. gr. 1.33 ; and boiling at —33.6° (—28°.5 F.). Chemical.—Chlorin exhibits a great tendency to combine with other elements, with all of which, except F, O, N, and C, it unites directly, frequently with evolution of light as well as heat, and sometimes with an explosion. With II 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 hydrochloric, chloric, and probably liypochlorous acids. The same change takes place slowly under the influence of sunlight, hence chlorin water should be kept in the dark or in bottles of yellow glass. In the presence of H20, chlorin is an active bleaching and dis- infecting agent. It acts as an indirect oxidant, decomposing H 20, the nascent O from which then attacks the coloring or odorous principle. Chlorin is readily fixed by many organic substances, either by addition or substitution. In the first instance, as when Cl and olefiant gas unite to form ethylene chlorid, the organic substance simply takes up one or more atoms of chlorin: C2H4 + Cl2 = C2H4CI0. In the second instance, as when Cl acts upon marsh gas to produce methyl chlorid : CI14 -f- Cl2 = CH;iCl -(- HC1, each CHLOKLX. 83 substituted atom of Cl displaces an atom of H, which combines with another Cl atom to form hydx-ochloric acid. Hydrate of chlorin, Cl 5H20, is a yellowish-green, crystalline substance, formed when Cl is passed through chlorin water, cooled to 0° (32° F.). It is decomposed at 10° (50° F.). Hydrogen Chlorid—Hydrochloric Acid—Muriatic Acid— Acidum Hydrochloricum (U. S.; Br.j—HC1—Molecular weight = 36.5—Sp. gr. 1.259 A—A litre weighs 1.6293 gram. Occurrence.—In volcanic gases and in the gastric juice of the mammalia. Preparation.—(1.) By the direct union of its constituent ele- ments. (2.) By the action of sulphuric acid upon a chlorid, a sulphate being at the same time formed : H3S04 + 2NaCl = Na2S04 -}- 2HC1. This is the reaction by which the HC1 used in the arts is pro- duced. (3.) Hydrochloric acid is also formed in a great number of reac- tions, as when Cl is substituted in an organic compound. Properties.—Physical. — A colorless gas, acid in reaction and taste, having a sharp, penetrating odor, and producing great irritation when inhaled. It becomes liquid under a pressure of 40 atmospheres at 4° (29° F.). It is very soluble in H20, one vol- ume of which dissolves 480 volumes of the gas at 0° (32° F.). Chemical.—Hydrochloric acid is neither combustible nor a sup- porter of combustion, although certain elements, such as K and Na, burn in it. It forms white clouds on contact with moist air. Solution of 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 im- pure), acid in taste and reaction, whose sp. gr. and boiling-point vary with the degree of concentration. When heated, it evolves HC1, if it contain more than 20 per cent, of that gas, and H20 if it contain less. A solution containing 20 per cent, boils at 111° (232° F.), is of sp. gr. 1.099, has the composition HCI-I-8H2O, and distils unchanged. Commercial muriatic acid is a yellow liquid ; sp. gr. about 1.16; contains 32 per cent. HC1 ; and contains ferric chlorid, sodium chlorid, 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 (IT. S.); sp. gr. 1.052 = 10.5 per cent. HC1 (Br.). 84 MANUAL OF CHEMISTRY. C. P. (chemically pure) acid is usually the same as the strong pharmaceutical 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 decom- posed by many elements, with formation of a clilorid and libera- tion of hydrogen : 2HC1 -\- Zn = ZnCl2 + H2. With oxids and hydrates of elements of the third and fourth classes it enters into double decomposition, forming H20 and a chlorid : CaO -j- 2HC1 = CaCl2 + H20 or CaH202 + 2HC1 = CaCl2 + 2H20. Oxidizing agents decompose HC1 with liberation of Cl. A mix- ture of hydrochloric and nitric acids in the proportion of three molecules of the former to one of the latter, is the acidum nitro- hydrochloricum (U. S. ; Br.), 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 solu- ble auric chlorid. "Impurities.—A chemically pure solution of this acid is exceed- ingly rare. The impurities usually present are: Sulphurous acid—hydrogen sulphid is given off when the acid is poured upon zinc ; Sulphuric acid—a white precipitate is formed with barium chlorid ; Chlorin colors the acid yellow ; Lead gives a black color when the acid is treated with hydrogen sulphid ; Iron—the acid gives a red color with ammonium sulphocyanate ; Arsenic—the method of testing by hydrogen sulphid is not suffi- cient. 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 sulphuric 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. Chlorids.—A few of the clilorids are liquid, SnCl4, SbCl5; the remainder are solid, crystalline and more or less volatile. The metallic chlorids are soluble in water, except AgCl, Hg2Cl2, which are insoluble, .and PbCl2, which is sparingly soluble. The chlorids of the non-metals are decomposed by H20. The chlorids are formed : 1.) By the direct union of the ele- ments: P -}- Cl5 = PC15; 2.) By the action of chlorin upon a heated mixture of oxid and carbon : A1203 + 3C -f- 3C12 = A12C16 + 3CO ; 3.) By solution of the metal, oxid, hydrate, or carbonate in HC1: Zn -|- 2HC1 = ZnCl2 -(- H2; 4.) By double decomposition between a solution of a chlorid and that of another salt whose metal forms an insoluble chlorid: AgXOs + NaCl = AgCl-f- NaNO.. Analytical Characters.—1.) With AgNOs a white,flocculent ppt., insoluble in HN03, soluble in NH4HO. 2.) With Hg2(N03)2, a white ppt., which turns black with NH4HO. CHLORIN. Toxicology.—Poisons and corrosives.—A poison is any sub- stance which, after entrance 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. The corrosives act much more energetically when concentrated than when dilute ; and when the dilution is great they have no deleterious action. The degree of concentration in which the true poisons are taken is of little influence upon their action if the dose taken remain the same. Under the above definitions the strong mineral acids act as corrosives rather than as poisons. They produce their injurious results by destroying 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 symptoms of corrosion by the mineral acids begin immedi- ately, during the act of swallowing. The chemical action of the acid upon every part with which it comes in contact causes acute burning pain, extending from the mouth to the stomach and intestine, referred chiefly to the epigastrium. Violent and dis- tressing vomiting of dark, tarry, or “ coffee-ground,” highly acid material is a prominent symptom. Eschars, at first white or gray, later brown or black, are formed where the acid has come in contact with the skin or mucous membrane. Respiration is labored and painful, partly by pressure of the abdominal muscles, but also, in the case of hydrochloric acid, from entrance of the irritating, acid gas into the respiratory passages. Death may occur within 24 hours, from collapse ; more suddenly from perforation of large blood-vessels, or from peritonitis ; or after several weeks, secondarily, from starvation, due to closure of the pylorus by inflammatory thickening, and destruction of the gastric glands. The object of the treatment in corrosion by the mineral acids is to neutralize the acid and convert it into a harmless salt. For this purpose the best agent is magnesia (magnesia usta), sus- pended in a small quantity of water, or if this be not at hand, a strong solution of soap. Chalk and the carbonates and bicar- bonates of sodium and potassium should not be given, as they generate large volumes of gas. The scrapings of a plastered wall, or oil, are entirely useless. The stomach-pump, or any attempt at the introduction of a tube into the oesophagus, is not to be thought of. Compounds of Chlorin and Oxygen.—Three compounds of chlorin and oxygen have been isolated, two being anhydrids. They ara 86 MANUAL OF CHEMISTRY. all very unstable, and prone to sudden and violent decomposi- tion. Chlorin Monoxid.—C120—87—Hypochlorous anhydrid or oxid, is formed by the action, below £0° (68° F.), of dry Cl upon pre- cipitated mercuric oxid : HgO -|- 2C12 = HgCl2 -f- Cl20. On contact with H20 it forms hypochlorous acid, HCIO, which, owing to its instability, is not used industrially, although the hypochlorites of Ca, K, and Na are. Chlorin Trioxid—Chlorous anhydrid or oxid, C1203—119—is a yel- lowish-green gas formed by the action of dilute nitric acid upon potassium chlorate in the presence of arsenic trioxid. At 50° (122° F.) it explodes. It is a strong bleaching agent ; is very irri- tating wdien inhaled and readily soluble in H20, the solution probably containing chlorous acid, HC102. Chlorin Tetroxid—Chlorin peroxid, C1204—135—is a violently explosive 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. It ex- plodes violently when heated to a temperature below 100° (212° F.). There is no corresponding hydrate known, and if it be brought in contact with an alkaline hydrate, a mixture of chlorate and chlorite is formed. Besides the above, two oxacids of Cl are known, the anhydrids corresponding to which have not been isolated. Chloric Acid—HC103—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—HC104—100.5—is the most stable of the series. It is obtained by boiling potassium chlorate with hydro- fluosilicic acid, decanting 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. BROMIN. Bromum, TJ.S., Br.—Symbol = Br—Atomic weight = 80—Molec- ular weight = 160—Sp. gr. of liquid = 3.1872 at 0° ; of vapor = 5.52 A—Freezing-point = — 24°.5 (—12°.1 F.)—Boiling-point = 03° (145°.4 F.)—Name derived from Ppuyog = a stench—Discovered by Balard in 1826. 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 evaporation of sea-water, and of that of certain mineral springs, and from sea-weed. These are mixed with sulphuric B HO MIX. 87 acid and manganese dioxid and heated, when the bromids are decomposed by the Cl produced, and Br distils. Properties.—Physical.—A dark reddish-brown liquid, volatile at all temperatures above — 34°.5 (—12°. 1 F.); giving off brown- red vapors which produce great irritation when inhaled. Solu- ble in water to the extent of 3.2 parts per 100 at 15° (59° F.); more soluble in alcohol, carbon disulphid, chloroform, and ether. Chemical.—The chemical characters of Br are similar to those of Cl, but less active. With HaO it forms a crystalline hydrate at 0° (32° F.) : Br 5H20. Its aqueous solution is decomposed by exposure to light, with formation of hydrobromic acid. It is highly poisonous. Hydrogen Bromid—Hydrobromic acid—Acidum hydrobromi- cum dil. (U. S.) = HBr—Molecular weight = 81—Sp. gr. = 2.71 A—A litre weighs 3.63 grams—Liquefies at — 09° (—92°.2 F.)— Solidifies at — 73° (— 99°.4 F.). Preparation.—This substance cannot be obtained from a bromid as HC1 is obtained from a clilorid. It is produced, along with phosphorous acid, by the action of HaO upon phosphorus tri- bromid : PBr3 -|- 3HaO = H3P03 + 3HBr ; or by the action of Br upon paraffin. Properties.—A colorless gas; produces white fumes with moist air ; acid in taste and reaction, and readily soluble in HaO, with which it forms a hydrate, HBr 2HaO. Its chemical properties are similar to those of HC1. Bromids closely resemble the clilorids and are formed under sim- ilar conditions. They are decomposed by chlorin, with formation of a chlorid and liberation of Br : 2KBr-}- Cla = 2KC1 -f- Bra. The metallic bromids are soluble in HaO, except AgBr and HgaBra, which are insoluble, and PbBra, which is sparingly soluble. The bromids of Mg, Al, Ca are decomposed into oxid and HBr oa evaporation of their aqueous solutions. Analytical Characters.—(1.) With AgNOs, a yellowisli-white ppt., insoluble in HN03, sparingly soluble inNH4HO. (2.) With chlorin water a yellow solution which communicates the same color to chloroform and to starch-paste. (3.) With palladic nitrate a black ppt. in the absence of clilorids. Oxacids of Bromin.—No oxids of bromin are known, although three oxacids exist, either in the free state or as salts : Hypobromous Acid—HBrO—97—is obtained, in aqueous solu- tion, by the action of Br upon mercuric oxid, silver oxid, or silver nitrate. When Br is added to concentrated solution of potassium hydrate no hypobromite is formed, but a mixture of bromate and bromid, having no decolorizing action. With sodium hy- MANUAL OF CIIEMISTKY. drate, however, sodium hypobromite is formed in solution ; and such a solution, freshly prepared, is used in Knop’s process for determining urea (q. v.). Bromic Acid—HBr03—129—has only been obtained in aqueous solution, or in combination. It is formed by decomposing barium bromate with an equivalent quantity of sulphuric acid : Ba (Br03)2+HoS04=2HBr03+BaS04. In combination it is pro- duced, along with the bromid, by the action of Br on caustic potassa : 3Br2 -f- 6KHO = KBr03 -\- 5KBr -f- 3H20. Perbromic Acid—HBrCh—145—is obtained on a comparatively stable, oily liquid, by the decomposition of perchloric acid by Br, and concentrating over the water-bath. It is noticeable in this connection that, while HC1 and the chlorids are more stable than the corresponding Br compounds, the oxygen compounds of Br are more permanent than those of Cl. IODIN. Iodum (U. S. ; Br.)—Symbol = I—Atomic weight = 127—Molec- ular weight — 254—Sp. gr. of solid = 4.948 ; of vapor = 8.716 A —Fuses at 113°.6 (236°.5 F.)—Boils at 175° (347° F.)—Name derived from iwdr/f = violet—Discovered by Courtois in 1811. Occurrence.—In combination with JSTa, K, Ca, and Mg, in sea- water, the waters of mineral springs, marine plants and animals. Cod-liver oil contains about 87 parts in 100,000. Preparation.—It is obtained from the ashes of sea-weed, called kelp or varech. These are extracted with 11,0, and the solution evaporated to small bulk. The mother liquor, separated from the other salts which crystallize out, contains the iodids, which are decomposed by Cl, aided by heat, and the liberated iodin condensed. Properties.—Physical.—Blue-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 H20, which, however, dissolves larger quantities on standing over an excess of iodin, by reason of the formation of hydriodic acid. The presence of certain salts, notably potassium iodid, increases the solvent power of H20 for iodin. The Liq. Iodi Comp. (U. IS.). Liq. Iodi, Br. is solution of potassium iodid containing free iodin. Very soluble in alcohol; Tinct. iodi (U. 8.; Br.)\ in ether, chloro- form, benzol, and carbon disulphid. 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 sulphid IODIN. 89 with formation of hydriodic acid, and liberation of sulphur. It does not combine directly with oxygen, but does with ozone. Potassium hydrate solution dissolves it, with formation of potas- sium iodid, and some hypoiodite. Citric acid oxidizes it to iodic acid. With ammonium hydrate solution it forms the explosive nitrogen iodid. Impurities.—Non-volatile substances remain when the I is heated. Water separates as a distinct layer when I is dissolved in carbon disulphid. Cyanogen iodid appears in white, acicular crystals among the crystals 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, iodin acts both as a local irri- tant and as a true poison. It is discharged as an alkaline iodid by the urine and perspiration, and when taken in large quantity it .appears in the fieces. 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. Hydrogen Iodid—Hydriodic acid—HI—Molecular weight— 128—Sp. gr. 4.443 A. Preparation.—By the decomposition of phosphorus triiodid by Avater : PI3 + 3H20 — H3P03 3HI. Or, in solution by passing hydrogen sulphid through water holding iodin in suspension : H2S -f I2 = 2HI + S. Properties.—A colorless gas, forming white fumes on contact with air, and of strongly acid reaction. Under the influence of cold and pressure it forms a yellow liquid, which solidifies at —55°(—G7° 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 H20 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. Chlorin and bromin decompose it, with liberation of iodin. With many metals it forms iodids. It yields up its H readily and is used in organic chemistry as a source of that ele- ment in the nascent state. Iodids—are formed under the same conditions as the chlorids and bromids, which they resemble in their properties. The metallic iodids are soluble in water except Agl, Hg2I2, which are insoluble, and Pbl2, which is very slightly soluble. The iodids of the earth metals are decomposed into oxid and HI on evapora- 90 MANUAL OF CHEMISTRY. tion of their aqueous solutions. Chlorin decomposes the iodids as it does the bromids; Analytical Characters.—(1.) With AgN03, a yellow ppt., insol- uble in HN03, and in NH4HO. (2.) With fuming HJST03 or with chlorin water, a yellow liquid, which colors starch-paste black or purple, and chloroform violet. (3.) With palladic nitrate, a black ppt., insoluble in cold HN03 and in solutions of alkaline chlorids, but forming a dark brown solution with alkaline iodids. Chlorids of Iodin.—Chlorin and iodin combine with each other in two proportions : Iodin monochlorid, or protochlorid—IC1 is a red-brown, oily, pungent liquid, formed by the action of dry Cl upon I, and distilling at 100° (212° F.). Iodin trichlorid or per- chlorid—IC13 is a yellow, crystalline solid, having an astringent, acid taste, and a penetrating odor ; very volatile ; its vapor irri- tating ; easily soluble in water. It is formed by saturating II20 holding I in suspension with Cl, and adding concentrated sul- phuric acid. IC13 has been used as an antiseptic. Oxacids of Iodin.—The best known of these are the highest two of the series—iodic and periodic acids. Iodic Acid—HI03—176—is formed as an iodate, whenever I is dissolved in a solution of an alkaline hydrate: I6 + 6KHO = KI03 -f- SKI -j- 3H20. 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 H20, the solution having an acid reaction, and a bitter, astringent taste. It is an energetic oxidizing agent, yielding up its O readily, with separation of elementary I or of HI. It is used as a test for the presence of morphin (g. v.). Periodic Acid—HIOi—192—is formed by the action of Cl upon an alkaline solution of sodium iodate. The sodium salt thus ob- tained is dissolved in nitric acid, treated with silver nitrate, and the resulting silver periodate decomposed with H20. From the solution the acid is obtained in colorless crystals, fusible at 130° (266° F.), very soluble in water, and readily decomposable by heat. II. SULPHUR GROUP. Sulphur—Selenium—Tellurium. The elements of this group are bivalent. With hydrogen they form compounds composed of one volume 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. SULPHUR. Their hydrates are dibasic acids. They are all solid at ordinary temperatures. The relation of their compounds to each other is shown in the following table : HaS SOa SOs HaSOa H4SO3 HaSO< H2Se SeOa Se03 HaSeOs HaSe04 HaTe TeOa Te03 HaTeOs HaTeO< Hydro-ic acid. Dioxid. Trioxid. Hypo-ous acid. -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 sulpliids and sulphates, and in albuminoid substances. Preparation.—By purification of the native sulphur, or decom- position oi pyrites, natural sulphids of iron. Crude sulphur is the product of a first distillation. A second distillation, in more perfectly constructed apparatus, yields re- fined sulphur. During the first part of the distillation, while the air of the condensing chamber is still cool, the vapor of S is sud- denly condensed into a tine, crystalline powder, which is flowers of sulphur, sulphur sublimatum (U. S.). Later, when the tem- perature 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 lovr temperatures, and in minute subdivision, as in the precipi- tated milk of sulphur, sulphur praecipitatum (U. S.), it is almost or quite colorless. Its taste and odor are faiTit but characteristic. At 114° (237°.2 F.) it fuses to a thin yellow 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 plas- tic sulphur, which may be moulded into any desired form. It is insoluble in water, sparingly soluble in anilin, phenol, benzol, benzin, and chloroform ; readily soluble in protochlorid of sul- phur and carbon disulphid. It dissolves in hot alcohol, and crys- tallizes from the solution, on cooling, in white prismatic crystals. It is dimorphous. When fused sulphur crystallizes it does so in oblique rhombic prisms. Its solution in carbon disulphid de- posits it on evaporation in rhombic octahedra. The prismatic MANUAL OF CHEMISTRY. variety is of sp. gr. 1.95 and fuses at 120 (248 F.) ; the sp. gr. ol 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, espe- cially at high temperatures. Heated in air or O, it burns with a blue flame to sulphur dioxid, S02. In H it burns with formation of hydrogen sulphid, H2S. 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 sul- phocyanic acid, CNSH, corresponding to cyanic acid, CNOH. Sulphur is used principally in the manufacture of gunpowTder ; also to some extent in making sulphuric acid, sulphur dioxid, and matches, and for the prevention of fungoid and parasitic growths. Hydrogen Monosulphid—Sulphydric acid—Hydrosulphuric acid—Sulphuretted hydrogen—H2S—Molecular weight = 34—Sp. gr. = 1.19 A. Occurrence.—In volcanic gases : as a product of the decomposi- tion of organic substances containing S ; in solution, in the waters of some mineral springs ; and, oc- casionally, in small quantity, in the gases of the intestine. 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 mix- ture become heated. (See Harsh test for arsenic.) (3.) By the action of HC1 upon antimony trisulphid: Sb2Ss+6HCl = 2SbCl3 + 3H2S. (4.) By the action of dilute sul- phuric acid upon ferrous sulphid : FeS+H2S04=FeS04+H2S. This is the method generally’ used. The gas should be purified by passage over dry calcium clilorid, then through a tube, 20 cent, long, loosely filled with solid iodin and, finally, through a solution of potassium sulphid. (5.) By’ the action of HC1 upon calcium sulphid : CaS -I-2HC1 = CaCl2 4- H2S. Fig. 24. SULPHUK. 93 The gas is usually obtained in the laboratory by reaction (4), either in an apparatus such as that shown in Fig. 20 (p. 43) or in one of the forms of apparatus shown in Figs. 24, 25. The sulphid is put into the bulb b, Fig. 24, through the opening e, or into the bottle b, Fig. 25. The dilute .acid, with which the uppermost and loAvest bulbs. Fig. 24, are filled, comes in contact Avitli the sulphid Fig. 25. when the stopcock is opened, or in the apparatus, Fig. 25, is poured through the funnel tube c. a is a wash-bottle partly filled with water. As ferrous sulphid is liable to contain arsenic, and as hydrogen sulphid generated from it may be contaminated with hydrogen arsenid, the gas, when required for toxicological analysis should always be obtained by reaction (5) in the apparatus, Fig. 24, or should be purified as above directed. Properties.—Physical.—A colorless gas, having the odor of rot- ten eggs and a disgusting taste ; soluble in H20 to the extent of 8.23 parts to 1 at 15° (59 F.); soluble in alcohol. Under 17 atmos- pheres pressure, or at —74° (—101°.2 F.) at the ordinary press- ure, it liquefies; at —85.5° (—122° F.) it forms white crystals. Chemical.—Burns in air with formation of sulphur dioxid and water: 2H2S + 30a = 2S02 + 2Ha0. If the supply of oxygen be deficient, H20 is formed, and sulphur liberated: 2H2S + 02 = 2H20 + Sa. Mixtures of H2S and air or O explode on contact with flame. Solutions of the gas when exposed to air become oxidized with deposition of S. Such solutions should be made Avith boiled H20, and kept in bottles Avhich are completely filled, and well corked. Oxidizing agents, Cl, Br, and I remove its H 94 MANUAL OF CHEMISTRY. with deposition of S. Hydrogen sulphid and sulphur dioxid mutually decompose each other into water, pentatliionic acid and sulphur: 4S02 + 3H2S = 2H-0 + HsSsOe + S2. 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 = HjO 4- KHS. With solutions of metallic salts H2S usually relinquishes its S to the metal : CuS04 -I- H2S = CuS 4- HySCh, a property which renders it of great value in analytical chemistry. Physiological.—Hydrogen sulphid is produced in the intestine by the decomposition of albuminous substances or of taurochloric acid; it also 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 atmos- phere of pure H2S, and the diluted gas is still rapidly fatal. An atmosphere containing one per cent, may be fatal to man, Fig. 26. 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 sulphid generally produces dele- terious effects is as a constituent of the gases emanating from sewers, privies, burial vaults, etc. These give rise to either sIoav 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 administra- tion of stimulants. After death the blood is found to be dark in color, and gives the spectrum shown in Fig. 20, due to sulphaemoglobin. Sulphids and Hydrosulphids.—These compounds bear the SULlMIUll DIOXID. same relation to sulphur that the oxids and hydrates do to oxy- gen. The two sulphids of arsenic, AaS3 and AaS», correspond to the two oxids, Aa03 and AaS5, and the liydrosulphid of potas- sium. KHS, corresponds to the hydrate, KHO. Many metallic sulphids occur in nature and are important ores of the metals, as the sulphids of zinc, mercury, cobalt, nickel, and iron. They are formed artificially, either by direct union of the elements at elevated temperatures, as in the case of iron : Fe + S = FeS ; or by reduction of the corresponding sulphate, as in the case of calcium : CaS04 —(— 2C = CaS + 2COa. The sulphids are insoluble in HaO, except those of the alkali metals. Many of the sulphids are soluble in alkaline liquids, and behave as sulphanhydrids, forming sulpho- or thio-salts, corresponding to the oxysalts. Thus potassium arsenate, K3 As04 and thioarsenate, K3AsS4; antimonate, K3Sb04, and thioantimo- nate, K3SbS4 The metallic sulphids are decomposed when heated in air, usually with the formation of sulphur dioxid and the metallic oxid ; sometimes with the formation of the sulphate ; and some- times with the liberation of the metal, and the formation of sul- phur dioxid. The strong mineral acids decompose the sulphids with formation of hydrogen monosulpliid. Analytical Characters.—Hydrogen Sulphid.—(1.) Blackens pa- per moistened with lead acetate solution. (2.) Has an odor of rotten eggs. Sulphids.—(1.) Heated in the oxidizing flame of the blowpipe, give a blue flame and odor of S0a. (2.) With a mineral acid give off HaS (except sulphids of Hg, Au, and Pt). Sulphur Dioxid—Sulphurous oxid, or anhydrid—Acidum sul- phurosum (TJ. S.; Br.)—S0a—Molecular weight = 64—Sp.gr. of gas — 2.213 ; of liquid — 1.45—Boils at—W (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 : 2HaS04 + Cu = CuS04 4- 2HaO + SOa. (5.) By heating sulphuric acid with charcoal : 2H2S04 + C = 2SOa + COa + 2HaO. (6.) By decomposing calcium sulphite, made into cubes with plaster of Paris, by HC1, at the ordinary temperature. When the gas is to be used as a disinfectant it is usually 96 MANUAL OF CHEMISTRY. obtained by reaction (1) ; in sulphuric acid factories (2) is used ; (3) indicates the method in which atmospheric ISO* is chiefly pro- duced ; in the laboratory (4) and (6) are used ; (5) is the process directed by the U. S. and Br. Pharmacopoeias. Properties.— Physical.—A colorless, suffocating gas, having a disagreeable and persistent taste. Very soluble in BUO, which at 15° (59° F.) dissolves about 40 times its volume (see below); also soluble in alcohol. At —10° (14° F.) it forms a colorless, mo- bile, transparent liquid, by whose rapid evaporation a cold of — 05° (—85° F.)is obtained. Chemical.—Sulphur dioxid is neither combustible nor a sup- porter of combustion. Heated with H it is decomposed : SO2 + 2Ha = S +2H20. With nascent hydrogen, H2S is formed: S02 + 3H2 = H2S + 2H2O. Water not only dissolves the gas, but combines with it to form the true sulphurous acid, H2SO3. With solutions of metallic hy- drates it forms metallic sulphites : S02 + KH0=KHS03; or S02 4- 2KHO‘= K2SO3 + H20. A hydrate having the composition H2SO3, 8H2O has been obtained as a crystalline solid, fusible at + 4° (39°.2 F.). Sulphur dioxid aqd sulphurous acid solution are powerful reducing agents, being themselves oxidized to sulphuric acid : SO2 + H2O + O =H2S04; or H2SO3 + O = H2SO4. It reduces nitric acid with formation of sulphuric acid and nitrogen tetroxid : S02 + 2HNO3 = H2SO4 + 2N02. It decolorizes organic pigments, without, however, destroying the pigment, whose color may be restored by an alkali or a stronger acid. It de- stroys H2S, acting in this instance, not as a reducing, but as an oxidizing agent : 4SOa + 3HaS = 2HaO + H2S6Oo + S.. With Cl it combines directly under the influence of sunlight to form sulphuril chlorid (SOs)' Cl2. Analytical Characters.—(1.) Odor of burning sulphur. (2.) Paper moistened with starcli-paste and iodic acid solution turns blue in air containing 1 in 3,000 of S02. Sulphur Trioxid—Sulphuric oxid or anhydrid—SO:i—Molecular weight = 80—Sp. gr. 1.95. Preparation.—(1.) By union of S02 and O at 250 -300’ (482 - 572° F.) or in presence of spongy platinum. (2.) By heating sulphuric acid in presence of phosphoric anhy- drid : H2SO4 + P2O5 = S03 + 2HP03. (3.) By heating dry sodium pyrosulphate : ]Sa2S207 = Na2S()4 + SO3. (4.) By heating pyrosulpliuric acid below 100c (212 F.), in a retort fitted with a receiver, cooled by ice and salt : H2S2O7 = H2SO4 + S03. OXACIDS OF SULPHUR. Properties.—White, silky, odorless crystals which give off white fumes in damp air. It unites with Ha0 with a hissing sound, and elevation of temperature, to form sulphuric acid. When dry it does not redden litmus. Sulphur trioxid exists in two isomeric (see isomerism) modifica- tions, being one of the few instances of isomerism among mineral substances. The a modification, liquid at summer temperature, solidifies in colorless prisms at 16° (60 .8 F.) and boils at 46J (114°.8 F.). The /? isomere is a white, crystalline solid which gradually fuses and passes into the a form at about 50° (122Q F.). Oxacids of Sulphur. H2SO2 Hyposulphurous acid. H2SO3 Sulphurous acid. H2SO4 Sulphuric acid. H2S2O7 Pyrosulpliuric acid. H2S2O6 Dithionic acid. HsSsOe Trithionic acid. H2S4O6 Tetratliionic acid. HiSsOo Pentatliionic acid. H2S2O3 Thiosulphuric acid. Hyposulphurous Acid—H2S02—66.—Hydrosulphurous acid—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. Sulphurous Acid—H2S03—82.—Although sulphurous acid has not been isolated, it, in all probability, exists in the acid solution, formed when sulphur dioxid is dissolved in water: S02 4- H20 = S03H2. Its salts, the sulphites, are well defined. From the ex- istence of certain organic derivatives (see sulphonic acids) it would seem that two isomeric modifications of the acid may exist. They are distinguished as the symmetrical, in which the S atom is quadrivalent, q a / OH ° - ®\OH’ and the unsymmetrical, in which the S atom is hexavalent 0\q/H 0/b\OH. Sulphites.—The sulphites are decomposed by the stronger acids, with evolution of sulphur dioxid. Nitric acid oxidizes them to sulphates. The sulphites of the alkali metals are soluble, and are active reducing agents. The analytical characters of the sulphites are: (1.) With HC1 they give off S02. (2.) With zinc and HC1 they give off H2S. (3.) With AgN03 they form a white ppt., soluble in excess of sulphite, and depositing metallic Ag when the mixture is boiled. (4.) With Ba(N03)2 they form a white ppt., soluble in HC1. If chlorin water 98 MANIAL OF CHEMISTRY. be added to the solution so formed a white ppt., insoluble in acids, is produced. Sulphuric Acid—Oil of Vitriol—Acidum sulphuricum (U. S.; Br.) —H,Sdr—98. Preparation.—(1.) By the union of sulphur trioxid and water : S03 + H,0 = H2S04. (2.) By the oxidation of S02 or of S in the presence of water : 2S02 + 2H20 + 02 = 2H2S04 ; or S2 + 2H20 + 302 = 2H2S04. The manufacture of H2S04 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 result 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 G5 per cent, of true sulphuric acid, H2S04. Into these chambers S02, obtained by burning sulphur, or by roast- ing pyrites, is driven, along with a large excess of air. In the chambers it comes in contact with nitric acid, at the expense of which it is oxidized to H2S04, while nitrogen tetroxid (red fumes) is formed : S02 + 2HN03 = H2S04 + 2N02. Were this the only reaction, the disposal of the red fumes would present a serious difficulty 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 dioxid are produced : 3N02 + H20 = 2HN03 + N0. The nitrogen dioxid in turn combines with O to produce the tetroxid, which then regenerates a further quantity of nitric acid, and so on. This series of reactions is made to go on contin- uously, the nitric acid being constantly regenerated, and acting merely as a carrier of 0 from the air to the S02, in such manner that the sum of the reactions may be represented by the equa- tion : 2S02 -I- 2H20 -I- 02 = 2H2S04. 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 industrial processes, is not yet strong enough for most purposes. It is concentrated, first by evaporation in shal- low leaden pans, until its sp. gr. reaches 1.74(5. 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 concentration and purity : (1.) The commercial oil of vitriol, largely used in manufactur- ing processes, is a more or less deeply colored, oily liquid, vary- OX ACIDS OF SULPHUR. ing in sp. gr. from 1.833 to 1.842, and in concentration from 93 per cent, to per cent, of true H2S04. (2.) C. P. acid = Acidum sulphuricum, V. 8. ; Br., of sp. gr. 1.84, colorless and comparatively pure (see below). (3.) Glacial sulphuric acid is a hydrate of the composition H2S04,H20, 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. 8. ; Br.) is a dilute acid of sp. gr. 1.069 and containing between 9 and 10 per cent. H2S04 (U. S.), or of sp. gr. 1.094, containing between 12 and 13 per cent. H2S04 (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 H20 have a lower boiling-point, and lower sp. gr. as the proportion of H20 increases. Chemical.—At a red heat vapor of H2S04 is partly dissociated into S03 and H20 ; or, in the presence of platinum, into SOi, 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 H30, 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 H20 produce an elevation of tem- perature to 130 (266° F.), and the resulting mixture occupies a volume 1-6 less than the sum of the volumes of the constituents. Strong H2S04 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 H20, the acid should be added to the H20 in a vessel of thin glass, to avoid the pro- jection of particles or the rupture of the vessel. It is by virtue of its affinity for H20 that H2S04 chars or dehydrates organic substances. Sulphuric acid is a powerful dibasic acid. Impurities.—The commercial acid is so impure that it is only fit for manufacturing and the coarsest chemical uses. The so- called C. P. acid may further contain : Lead ; becomes cloudy when mixed with ten times its volume of H20, if the quantity of Pb be sufficient. The dilute acid gives a black color wfith H2S. Salts; leave a fixed residue when the acid is evaporated. Sul- phur dioxid ; gives off H2S wfiien the acid, diluted with an equal volume of H20, comes in contact wfith Zn. Carbon; communi- cates a brown color to the acid. Arsenic; is very frequently present. When the acid is to be used for toxicological analybis, the test by H2S is not sufficient. The acid, diluted with an equal 100 MANUAL OF CHEMISTRY. volume of H20, is to be introduced into a Marsh apparatus, in which no visible stain should be produced during an hour. Oxids of nitrogen; are almost invariably present; they communicate a pink or red color to pure brucin. Sulphates.—Sulphuric acid being dibasic, there exist two sul- phates of the univalent metals : HKS04 and K2S04, and but one sulphate of each bivalent metal: CaS04. The sulphates of Ba, Ca, Sr, and Pb are insoluble, or very sparingly soluble, in H20. Other sulphates are soluble in H20, but all are insoluble in alcohol. Analytical Characters.—(1.) Barium chlorid (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. (8.) Calcium chlorid forms a white ppt., either immedi- ately or on dilution with two volumes of alcohol; insoluble in dilute HC1 or HNO,. 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 (esophagus, 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 is the same as that for corrosion by HC1. (See p. 85.) Thiosulphuric Acid—Hyposulphurous acid—H2S2O3—114—may be considered as sulphuric acid, H2SO4, in which one atom of oxygen has been replaced by one of sulphur. The acid itself lias not been isolated, being decomposed, on liberation from the thio- sulphates, into sulphur, water and sulphur dioxid : H2S2O3 = S + 80s + H2O. Pyrosulphuric Acid.—Fuming sulphuric acid—Nordhausen oil of vitriol—Disulphuric hydrate—H2S207—Molecular weigh t = 178 —Sp. gr. = 1.9—Boils at 52°.2 (126° F.). Preparation.—By distilling dry ferrous sulphate ; and purifica- tion of the product by repeated crystallizations and fusions, until a substance fusing at 85° (95n F.) is obtained. Properties.—The commercial Nordhausen acid, which is a mix- ture of H2S2O7 with excess of S03, or of H2S04, is a brown, oily liquid, which boils below 100c (212° F.) giving off S03 ; and is solid or liquid according to the temperature. It is used chiefly as a solvent for indigo, and in the anilin industry. 101 NITROGEN. SELENIUM AND TELLURIUM. Se—79.5. Te—128. These are rare elements which form compounds similar to those of sulphur. Elementary selenium is used in some forms of elec- trical apparatus. III. NITROGEN GROUP. Nitrogen—Phosphorus—Arsenic—Antimony. The elements of this group are trivalent or quinquivalent, oc- casionally univalent. With hydrogen they form non-acid com- pounds, 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 hydrates are acids containing one, two, three, or four atoms of replaceable hy- drogen. Bismuth, frequently classed in this group, is excluded, owing to the existence of the nitrate Bi(N03)3. The relations existing between the compounds of the elements of this group are shown in the following table: nh3, PH:, AsHs, SbH3, NaO, NO, N3O3, P3O3, ASaOs, Sb303, NO,, Na05, p3os, AS305, SbaOs, H3PO„ Hyd- rid. Mon- oxid. Di- oxid. Tri- oxid. Tetr- oxid. Pent- oxid. Hypo-ous acid. H3PO3, H3As03, h3po4, H3As04, H3Sb04, H4P507, HiAsjOtj H4Sba07, HNO3 HPO, HAsOs HSbCb -ous acid. Ortho-ic acid. Pyro-ic acid. Meta-ic acid. NITROGEN. Azote—Symbol=TX—Atomic weight=\\—Molecular weight— —Sp. gr.— 0.9701—One litre weighs 1.254 grams—Name from v'LTpov=nitre, yheaig—source ; or from a,, privative £uij=life—Dis- covered by Mayoio in 1669. Occurrence.—Free in atmospheric air and in volcanic gases. In combination in the nitrates, in ammoniacal compounds and in a great number of animal and vegetable substances. Preparation.—(1.) By removal of O from atmospheric air; by 102 MANUAL OF CHEMISTRY. burning P in air, or by passing air slowly over red-hot copper. It is contaminated with C02, H20, etc. (2.) By passing Cl through excess of ammonium hydrate solu- tion. If ammonia be not maintained in excess, the Cl reacts with the ammonium chlorid formed, to produce the explosive nitrogen chlorid. (3.) By heating ammonium nitrite, (NIL) N02: or a mixture of ammonium chlorid 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 com- pounds are very prone to decomposition, which may occur ex- plosively or slowly. Nitrogen combines directly with O under the influence of electric discharges; and with H under like condi- tions, and, indirectly, during the decomposition of nitrogenized organic substances. It combines directly with magnesium, boron, vanadium and titanium. Nitrogen is not poisonous, but is incapable of supporting respi- ration. Atmospheric Air.—The alchemists considered air as an element, until Mayow, in 1G69, 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 mechani- cal mixture 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; proportions which vary but very slightly at dif- ferent 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 pro- portion 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 H20 at 14°. 1 (57.4 F.) consists of N and O, not in the proportion given above, but in the proportion 66.76 to 33.24. Besides these two main constituents, air contains about 4-5 NITROGEN. 103 thousandths of its bulk of other substances: vapor of wator, car- bon dioxid, ammoniacal compounds, hydrocarbons, ozone, oxids 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 Ha0 which a given volume of air can hold, without precipitation, varies ac- cording to the temperature and the pressure. It happens rarely that air is as highly charged with moisture as it is capable of being for the existing temperature. The difference between the amount of water which the air is capable of holding at the exist- ing temperature, and that which it actually does hold is it* frac- tion of saturation, or hygrometric state, or relative humidity. 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 “ stuffi- ness ” so common in furnace-heated houses. If it be greater, evap- oration 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 chlorid; whose increase in weight represents the amount of HaO in the volume of air used. The fraction of saturation is determined by instru- ments called hygrometers, hygroscopes or psychrometers. Carbon dioxid.—The quantity of carbon dioxid in free air varies from 3 to 6 parts in 10,000 by volume. (See Carbon dioxid.) Ammoniacal compounds.—Carbonate, nitrate, and nitrite of ammonium occur in small quantity (0.1 to 0.0 parts per million of KH3) 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 ammo- nium, are produced either by the oxidation of combustible sub- stances containing N, or by direct union of N and H20 during discharges of atmospheric electricity. Rain-water, falling during thunder-showers, has been found to contain as much as 3.71 per million of HN03. (See Hydrogen peroxid, p. 77.) 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 detected in the air of cities, and of swampy places, in small quantities. Solid particles of the most diverse nature are always present in air and become visible in a beam of sunlight. Sodium chlorid is almost always present, always in the neighborhood of salt water. Air contains myriads of germs of vegetable organisms, mould, 104 MANUAL OF CHEMISTRY. etc., which are propagated by the transportation of these germs by air-currents. It seems probable, also, that the germs or poi- sons by which certain diseases are propagated float in the air. The continued inha- lation of air containing large quantities of solid particles in suspension may cause severe pul- monary disorder, by mere mechanical irrita- tion, 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, furni- ture-polishers, metal- filers, etc. Atmospheric dust is best collected by an in- strument such as is shown in Fig. 27. A disk of thin glass is fastened upon the plate b, over the small opening in A, and its lower surface moistened with a mix- ture of equal parts of water and glycerin, the opening C is con- nected with an aspirator. After one or more cubic metres of air have been drawn through the apparatus, the thin glass is de- tached and the deposit examined microscopically. The deposit may be also examined for bacteria by the proper methods. Fig. 27. Ammonia. Hydrogen nitrid—Volatile alkali—NH3—Molec- ular weight=17—ftp. gr. =0.589 A—Liquefies at— 40° (—40° F.)— Boils at —33°.7 (—28°.7 F.)—Solidifies at —75° (—103° F.)—A litre weighs 0.7655 gram. Preparation.—(1.) By union of nascent H with N. (2.) By decomposition of organic matter containing N, either spontaneously or by destructive distillation. (8.) By heating a mixture of dry slacked lime with ammonium clilorid: 2NH4C1 + CaH202 = CaCl, + 2HaO + 2NH3. (4.) By heating solution of ammonium hydrate: NH4HO = NH, +Ha0. Properties.—Physical.—A colorless gas, having a pungent odor, and an acrid taste. It is very soluble in H30, 1 volume of which NITROGEN. 105 at 03 (32° F.) dissolves 1050 vols. NH3, and at 15° (59 F.), 727 vols. NH3. Alcohol and ether also dissolve it readily. Liquid ammo- nia is a colorless, mobile fluid, used in ice machines for producing artificial cold, the liquid absorbing a great amount of heat in volatilizing. Chemical.—At a red heat ammonia is decomposed into a mix- ture 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 electricity. It is not readily combustible, yet it burns in an atmosphere of O with a yellowish flame. Mixtures of NH3 with O, nitrogen monoxid, or nitrogen dioxid, explode on contact with flame. The solution of ammonia in H20 constitutes a strongly alkaline liquid, known as aqua ammonise, which is possessed of strongly basic properties. It is neutralized by acids with the formation of crystalline salts, which are also formed, without liberation of hy- drogen, by direct union of gaseous NH3, with acid vapors. The ammoniacal salts and the alkaline base in aqua ammonise are compounds of a radical, ammonium, NH,, which forms compounds corresponding to those of potassium or sodium. The compound formed by the union of ammonia and water is ammonium hydrate or hydroxid, NH,HO: NH3-|-H20 = NH4HO; and that formed by the union of hydrochloric acid and ammonia is ammonium chlorid, NH.Cl: NH3 + HC1 = NH4C1. Hydroxylamin—NHsHO—33.—The arnins and amids (q.v.) are compounds derived from ammonia by the substitution of radicals for a part or all of its hydrogen. This substance, which is intermediate in composition between ammonia and am- monium hydrate, may be considered as ammonia, one of whose hydrogen atoms has been replaced by the radical hydroxyl, HO. It is obtained in aqueous solution by the union of nascent hydro- gen with nitrogen dioxid: NO + H3 = NH2HO; or by the action of nascent hydrogen upon nitric acid: HN03-j-3H2 = 2H20 -j- NH2 HO. Hydroxylamin is only known in solution and in combination. Its aqueous solution, which probably contains the corresponding hydrate, NH30, HO, is strongly alkaline and behaves with regard to acids as does ammonium hydrate solution, forming salts cor- responding to those of ammonium. Thus hydroxylammonium chlorid, NH«0C1, crystallizes in prisms or tables, fusible at 100° (212° F.), and decomposed into HC1, H20 and NH4C1 at a slightly higher temperature. Hydroxylammonium chlorid has been used in the treatment of cutaneous disorders. It is an actively toxic agent, converting oxyhemoglobin into methsemoglobin. 106 MANUAL OF CHEMISTRY. Nitrogen Monoxid. Nitrous oxid—Laughing gas—Nitrogen protoxid—N20—Molecular weight—^—Sp. gr. = 1.527A—Fuses at — 100° (—148° F.)—Boils at —87° (—124° F.)—Discovered in 1770 by Priestley. Preparation. — By heating ammonium nitrate: (NH4)N03 = Na0 + 2H20. To obtain a pure product there should be no am- monium chlorid 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-bot- tles containing sodium hydrate and ferrous sulphate. Properties. — Physical. — A colorless, odorless gas, having a sweetish taste; soluble in H20; more so in alcohol. Under a pressure of 30 atmospheres, at 0° (32° F.), it forms a colorless, mo- bile liquid which, when dissolved in carbon disulphid and evaporated in vacuo, produces a cold of —140° (— 220° F.). Chemical.—It is decomposed by a red heat and by the contin- uous 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 proportions of these elements, it is capable of main- taining respiration longer than any gas except oxygen or air; an animal will live for a short time only in an atmosphere of pure nitrous oxid. When inhaled, diluted with air, it produces the effects first observed by Davy in 1799: first an exhilaration of spirits, frequently accompanied by laughter, and a tendency to muscular activity, the patient sometimes becoming aggressive; afterward there is complete amesthesia, and loss of consciousness. It has been much used, by dentists especially, as an anaesthetic in operations of short duration, and in one or two instances an- aesthesia 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 Dioxid. Nitric oxid—NO—Molecular 'weight—30— Sp. gr. =1.039A—Discovered by Hales in 1772. Preparation.—By the action of copper on moderately diluted nitric acid in the cold: 3Cu + 8HN03 = 3Cu(N03)2 + 4H20 + 2NO; the gas being collected after displacement of air from the ap- paratus. Properties.—A colorless gas, whose odor and taste are unknown; very sparingly soluble in HA); more soluble in alcohol. It combines with O, when mixed with that gas or with air, to form the reddish-brown nitrogen tetroxid. It is absorbed by solution of ferrous sulphate, to which it communicates a dark NITROGEN. 107 brown or black color. It is neither combustible nor a good sup- porter 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 Trioxid. Nitrous anhydrid—N203—76—Is prepared by the direct union of nitrogen dioxid and oxygen at low temper- atures, or by decomposing liquefied nitrogen tetroxid with a small quantity of H20 at a low temperature: 4N02 -f- H20 = 2HNOs -f- N203. It is a dark indigo-blue liquid, which, boiling at about 0° (32° F.), is partly decomposed. It solidifies at — 82° (— 115°.6 F.). Nitrogen Tetroxid. Nitrogen peroxid—Hyponitric acid—Ni- trous fumes—N02—Molecular weight=46—tip. gr.=1.58A (at 154° C.)—Boils at 22° (71°.6 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 pro- duced : 2Pb(N03)2 = 2PbO + 4N02 + O,. (B.) 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 ni- tric acid is decomposed by starch or by a metal, consist of N02, mixed with N203. It dissolves in nitric acid, forming a dark yel- low liquid, which is blue or green if N203 be also present. With SOa it combines to form a solid, crystalline compound, which is sometimes produced in the manufacture of H2S04. This sub- stance, which forms the lead chamber crystals, is a substituted sul- phurous acid, nitrosulphonic acid, NO .SO.OH (see sulphonic acids). A small quantity of H20 decomposes N02 into HN03and N203, which latter colors it green or blue. A larger quantity of H20 decomposes it into HN03 and NO. By bases it is transformed into a mixture of nitrite and nitrate: 2N02 -f- 2KHO = KN02 -f- KN03+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 substituted as an univalent radical; thus with benzol it forms nitro-benzol: C6H5(N02). Toxicology.—The brown fumes given off during many processes, in which nitric acid is decomposed, are dangerous to life. All such operations, when carried on on a small scale, as in the labor- atory, should be conducted under a hood or some other arrange- ment, by which the fumes are carried into the open air. When, 108 MANUAL OF CHEMISTRY. 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 H2S04 or absorbed by H20 or an alkaline solution. An atmosphere contaminated with brown fumes is more dan- gerous 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 lungs 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 Pentoxid. Nitric anhydrid— N206 — Molecular weight—108—Fuses at 30° (86° F.)—Boils at 47° (116°.6 F.). Preparation.—(1.) By decomposing dry silver nitrate with dry Cl in an apparatus entirely of glass: 4AgN03-f-2Cl2=4AgCl-l- (2.) By removing water from fuming nitric acid with phosphorus pentoxid: 6HN03+P206=2H3P04+3N205. 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 ICO, with which it forms nitric .acid; and even spontaneously. Most substances which combine readily with O, remove that element from Ns06. Nitrogen Acids.'—Three are known, either free or in combina- tion, corresponding to the three oxids containing uneven num- bers of O atoms: N20 -f- H20 = H2N2O2—Hyponitrous acid. N2O3 -j- H2O = 2HNO2—Nitrous acid. N2O5 -j- H2O = 2HN03—Nitric acid. Hyponitrous acid—H2N202—31—Known only in combination. Silver liyponitrite is formed by reduction of sodium nitrate by nascent H and decomposition with silver nitrate. Nitrous acid—HN02—47—has not been isolated, although its salts, the nitrites, are well-defined compounds: M'NOa or M"(NOa)a. The nitrites occur in nature, in small quantity, in natural waters, where they result from the decomposition of nitrogenous NITKOGEN. organic substances; also in saliva. They are produced by heat- ing the corresponding nitrate, either alone or in the presence of a readily oxidizable metal, such as lead. Solutions of the nitrites are readily decomposed by the mineral acids, with evolution of brown fumes. They take up oxygen readily and are hence used as reducing agents. Solutions of potassium permanganate are in- stantly decolorized by nitrites. A mixture of thin starch paste and zinc iodid solution is colored blue by nitrites, which decom- pose the iodid, liberating the iodin. A solution of metaphenvlen- diamin, in the presence of free acid, is colored brown by very minute traces of a nitrite, the color being due to the formation of triamido-azobenzol (Bismark brown). Nitric Acid. Aquafortis—Hydrogen nitrate—Acidum nitri- cum—U.S. ; Br.—HN03—63. Preparation.—(1.) By the direct union of its constituent ele- ments under the influence of electric discharges. (2.) By the decomposition of an alkaline nitrate by strong H2SO4. With moderate heat a portion of the acid is liberated- 2jNaN03-|-H2S04=NaHS04+NaN03-fHN03, and at a higher tem- perature the remainder is given off: NaN03-|-NaHS04=Na2SC)4-f- HNO3. This is the reaction used in the manufacture of HN03. Varieties.—Commercial—a yellowish liquid, impure, and of two degrees of concentration: single aquafortis; sp. gr. about 1.25 = 39# HN03; and double aquafortis; sp. gr. about 1.4=64# HN03. Fuming—a reddish-yellow liquid, more or less free from impuri- ties; charged with oxids 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 ni- tricum, TJ. S.; Br.—a colorless acid, of sp. gr. 1.42=70# HN03. Acidum nitricum dilutum, XJ. S.; Br.—the last mentioned, diluted with H20 to sp. gr. 1.059=10# HNO3 (U. $.), or to sp. gr. 1.101 =17.44# HNO3 (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 reac- tion. 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.), when it remains constant, the sp. gr. of distilled and distillate being 1.42=70# HN03. 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 strongly heated, HN03 is decomposed into NCh; H20 and O. Nitric acid is a valuable oxydant; it converts I, P, S, C, B, and Si or their 110 MANUAL OF CHEMISTRY. lower oxids into their highest oxids; it oxidizes and destroys most organic substances, although with some it forms products of sub- stitution. Most of the metals dissolve in HNOs as nitrates, a portion of the acid being at the same time decomposed into NO and H20 : 4HN03-|-3Ag=3AgN03+N0-|-2H20. The chemical ac- tivity of HN03 is much reduced, or even almost arrested, when the intervention of nitrous acid is prevented by the presence of carbamid. The so-called “ noble metals,” gold and platinum, are not dissolved by either HN03 or HC1, but dissolve as chlorids in a mixture of the two acids, called aqua regia. In this mixture the two acids mutally decompose each other according to the equations: HN03+3HC1=2H20+N0C1+Cl2 and 2HN03+6HC1 =4H20-f2N0Cl2-|-Cl2 with formation of nitrosyl chlorid, NO Cl and bichlorid, NOCh, and nascent Cl; the last named combin- ing with the metal. Iron dissolves easily in dilute HN03, but if dipped into the concentrated acid, it is rendered passive, and does not dissolve when subsequently brought in contact with the dilute acid. This passive condition is destroyed by a temper- ature of 40° (104° F.) or by contact with Pt, Ag or Cu. When HN03 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.—Oxids of Nitrogen render the acid yellow, and de- colorize 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. Chlorin, iodin cause a white ppt. with AgNOs. Iron gives a red color wrhen the diluted acid is treated with ammonium sulphocyanate. Salts, leave a fixed residue when the acid is evaporated to dryness on platinum. Nitrates.—The nitrates of K and Na occur in nature. Nitrates are formed by the action of HN03 on the metals, or on their oxids or carbonates. They have the composition M'N03, M"(N03)2 or M'"(N03)s, except certain basic salts, such as the sesquibasic lead nitrate, Pb(N03)2, 2PbO. With the exception of a few basic salts, the nitrates are all soluble in water. When heated, they fuse and act as powerful oxidants. They are decomposed by H2S04 with liberation of HNOs. Analytical Characters.—(1.) Add an equal volume of concen- trated H2S04, cool, and float on the surface of the mixture a solu- tion of FeS04. 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 sulpliindigotic 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 NITROGEN. the residue a few drops of H2SO4 and a crystal of bruein (or some sulplianilic acid); a red color is produced. (4.) Add HoSCh and Cu to the suspected liquid and boil, brown fumes appear (best visible by looking into the mouth of the test- tube). (5.) A solution of diphenylamin in concentrated H2S04 (.01 grin, in 100 c.c.) is colored blue by nitric acid A similar color is pro- duced by other reducing agents. (6.) To 0.5 c.c. nitrate solution add 1 drop aqueous solution of resorcin (10$), and 1 drop HC1 (15$), and float on the surface of 2 c.c. concentrated H2SO4; a purple-red band. 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 H3S04 or HC1 have been taken; i.e. neutralization of the corrosive by magnesia or soap. Compounds of Nitrogen with the Halogens.—Nitrogen chlorid— NCls—120.5—is formed by the action of excess of Cl upon NH3 or an ammoniacal 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 con- tact with phosphorus, alkalies or greasy matters it is decomposed, with a violent explosion, into one volume N and three volumes Cl. Nitrogen bromid—NBr:i—254—has been obtained, as a reddish- brown, syrupy liquid, very volatile, and resembling the chlorid in its properties, by the action of potassium bromid upon nitro- gen chlorid. Nitrogen iodid—NI3—395—When iodin is brought in contact with ammonium hydrate solution, a dark brown or black powder, highly explosive when dried, is formed. This substance varies in composition according to the conditions under which the action occurs; sometimes the iodid alone is formed; under other circum- stances it is mixed with compounds containing N, I and H. 112 MANUAL OF CHEMISTKY. PHOSPHORUS. Symbol—Atomic weight—31—Molecular weight=124:—Sp_ gr. o/mpor=4.2904 A—Name from light, ° 0=P—O—H NO—H Pyrophosphoric acid: Metaphosphoric acid : /O—H 0=P—O NO Only those H atoms which are connected with the P atoms through 0 atoms are basic. Hence H3P02 is monobasic; HsPOs is dibasic; H3P04 is tribasic; H4P207 is tetrabasic, and HPOs is monobasic. Hypophosphorous acid—H:,PO.—GG—is a crystalline solid, or, PHOSPHORUS. 119 more usually, a strongly acid, colorless syrup. It is oxidized by air to a mixture of H3P03 and H3P04. The hypophosphites as well as the free acid, are powerful re- ducing agents. Phosphorous acid—H3P03—82—is formed by decomposition of phosphorous trichlorid by water: PCl3-j-8H30=H3P03-{-3HCl. It is a highly acid syrup, is decomposed by heat, and is a strong re- ducing agent. Phosphoric acid— Orthophosphoric acid—Common, or tribasic, phosphoric acid—Acidum phosphoricum, U. S.; Br.—H PO,—98— does not occur free in nature, but is widely disseminated in com- bination, in the phosphates, in the three kingdoms of nature. It is prepared: (1) By converting bone phosphate, Ca3(P04)3, into the corresponding lead or barium salt, Pb3(P04)2 or Ba3(P04)3, and decomposing the former by H3S, or the latter by H3S04. (2) By oxidizing P by dilute HNOa, aided by heat. The operation should be conducted with caution, and heat gradually applied by the sand-bath. It is best to use red phosphorus. This is the process directed by the U. S. and Br. Pharm. The concentrated acid is a colorless, transparent, syrupy liquid; still containing H20, which it gives off on exposure over H3SU4, leaving the pure acid, in transparent, deliquescent, prismatic crystals. It is decomposed by heat to form, first, pyrophosphoric acid, then metaphosphoric acid. It is tribasic. If made from arsenical phosphorus, and commercial phosphorus is usually arsenical, it is contaminated with arsenic acid, whose presence may be recognized by Marsh’s test (q. v.). The acid should not respond to the indigo and ferrous sulphate tests for hno3. Phosphates.—Phosphoric acid being tribasic the phosphates have the composition M H3P04; M 2HP04; M’3P04; M "(H3P04)3; M%(HP04); M"3(P04); M M'P04; and M "P04. The monometallic salts are all soluble and are strongly acid. Of the dimetallic salts, those of the alkali metals only are soluble and their solutions are faintly alkaline; the others are unstable, and exhibit a marked tendency to transformation into monometallic or trimetallic salts. The normal phosphates of the alkali metals are the only soluble trimetallic phosphates. Their solutions are strongly akaline, and they are decomposed even by weak acids: Na3P04 + C03H3 = HNa3P04 + HNaCO-, Trisodic phosphate. Carbonic acid. Disodic phosphate. Monosodic carbonate. All the monometallic phosphates, except those of the alkali metals, are decomposed by ammonium hydrate, with precipita- tion of the corresponding trimetallic salt. MANUAL OF CHEMISTRY. Analytical Characters.—(1) With ammoniacal solution of silver nitrate, a yellow precipitate. (2) With solution of ammonium molybdate in HN03, a yellow precipitate. (3) With magnesia mixture,* a white, crystalline precipitate, soluble in acids, insolu- ble in ammonium hydrate. Pyrophosphoric acid — H,P.07 —178. — When orthophosphoric acid (or hydro-disodic phosphate) is maintained at 213° (415°.4 F.), two of its molecules unite, with the loss of the elements of a molecule of water: 2H3P04=H4P207+H20, to form pyrophos- phoric acid. Metaphosphoric acid—Glacial phosphoric acid—HP03—80—is formed by heating H3P04 or H4P207 to near redness: H3PO«= HP03-)-H20; or H4P207=2HP03-f-H20. It is usually obtained from bone phosphate; this is first converted into ammonium phosphate, which is then subjected to a red heat. It is a white, glassy, transparent solid, odorless, and acid in taste and reaction. Slowly deliquescent in air, it is very soluble in H20, although the solution takes place slowly, and is accom- panied by a peculiar crackling sound. In constitution and basic- ity it resembles HJIOs. The metaphosphates are capable of existing in five polymeric modifications (see polymerism): Mono- di- tri- tetra- and hexmeta- phosphates: M'P03; M'2(P03)2 and M"(P03)2; M'3(P03)3; M'4(P03)4 and M"2(P03)4; and M'6(P03)6. Action of the Phosphates on the Economy.—The salts of ortho- phosphoric acid are important constituents of animal tissues, and give rise, when taken internally, in reasonable doses, to no un- toward symptoms. The acid itself may act deleteriously, by vir- tue of its acid reaction. Meta- and pvro-phosphoric acids, even when taken in the form of neutral salts, have a distinct action (the pyro being the more active) upon the motor ganglia of the heart, producing diminution of the blood-pressure, and, in com- paratively small doses, death from cessation of the heart’s action. Compounds of Phosphorus with the Halogens.—Phosphorus tri- chlorid—PC13—137.5—is obtained by heating P in a limited supply of Cl. It is a colorless liquid; sp. gr. 1.61; has an irritating odor; fumes in air; boils at 76° (169° F.). Water decomposes it with formation of H3P03 and HC1. Phosphorus pentachlorid—PC15—208.5—is formed when P is burnt in excess of Cl. It is a light yellow, crystalline solid: gives off irritating fumes; and is decomposed by H20. Phosphorus oxychlorid — P0C13 —153.5 — is formed by the ac- * Made by dissolving 11 pts. crystallized magnesium chlorid and 28 pts. ammo- nium chlorid in 130 pts. water, adding 70 pts. dilute ammonium hydrate and filtering after two days. ARSENIC. 121 tion of a limited quantity of H20 on the pentachlorid: PCls-{- H20=P0Cl3-(-2HCl. It is a colorless liquid; sp. gr. 1.7; boils at 110 (230° E.); and solidifies at —10° (+14° F.). With bromin P forms compounds similar in composition and properties to the chlorin compounds. With iodin it forms two compounds, PIa and PI3. With fluorin it forms two compounds, PF3 and PF3, the former liquid, the second gaseous. ARSENIC. Symbol=As—Atomic weight=75—Molecular weight^800—Sp. gr. of solid=5.75 ; of vapor=li). 6J. at 860° (1580° F.)—Name from apacviKov—orpi merit. Occurrence.—Free in small quantity; in combination as ar- senids of Fe, Co, and Ni, but most abundantly in the sulphids, orpiment and realgar, and in arsenical iron pyrites or mispickel. Preparation.—(1.) By heating mispickel in clay cylinders, which communicate with sheet iron condensing tubes. (2.) By heating a mixture of arsenic trioxid and charcoal; and purifying the product by resublimation. Properties.—Physical.—A brittle, crystalline, steel gray solid, having a metallic lustre, or a dull, black, amorphous solid. At the ordinary pressure, and without contact of air, it volatilizes without fusion at 180° (256° F.); under strong pressure it fuses at a dull red heat. Its vapor is yellowish, and has the odor of gar- lic. It is insoluble in H20 and in other liquids unless chemically altered. Chemical.—Heated in air it is converted into the trioxid and ignites somewhat below a red heat. In O it burns with a bril- liant, bluish-white light. In dry air it is not altered, but in the presence of moisture its surface becomes tarnished by oxidation. In HaO it is slowly oxidized, a portion of the oxid dissolving in the water. It combines readily with Cl, Br, I, and S, and with most of the metals. With H it only combines when that element is in the nascent state. Warm, concentrated H2SO4 is decom- posed by As, with formation of S02, As203, and H20. Nitric acid is readily decomposed, giving up its O to the formation of arsenic acid. With hot HC1, arsenic trichlorid is formed. When fused with potassium hydrate, arsenic is oxidized, H is given off, and a mixture of potassium arsenite and arsenid remains, which by greater heat is converted into arsenic, which volatilizes, and potassium arsenate, which remains. Elementary arsenic enters into the composition of fly poison and of shot, and is used in the manufacture of certain pigments and fire-works. 122 MANUAL OF CHEMISTRY. Compounds of Arsenic and Hydrogen.—Two are known: the solid As2H (?), and the gaseous, AsH3. Hydrogen arsenid—Arseniuretted or arsenetted hydrogen=Ar- senia—Arsenamin—AsHa—Molecular weight—IQ—tip. gr.= 2.695 A—Liquefies at —40° (—40° P.). Formation.—(1.) By the action of H20 upon an alloy, obtained by fusing together native sulphid of antimony, 2 pts.; cream of tartar, 2 pts.; and arsenic trioxid, 1 pt. (2.) By the action of dilute HC1 or H2S04 upon the arsenids of Zn and Sn. (3.) Whenever a reducible compound of arsenic is in presence of nascent hydrogen. (See Marsh test.) (4.) By the action of H20 upon the arsenids of the alkali metals. (5.) By the combined action of air, moisture and organic mat- ter upon arsenical pigments. (G.) By the action of hot solution of potassium hydrate upon reducible compounds of As in the presence of zinc. Properties.—Physical.—A colorless gas; having a strong allia- ceous odor; soluble in 5 vols. of H20, free from air. Chemical.—It is neutral in reaction. In contact with air and moisture its H is slowly removed by oxidation, and elementary As deposited. It is also decomposed into its elements by the pas- sage through it of luminous electric discharges; and when sub- jected to a red heat. It is acted on by dry 0 at ordinary temper- atures with the formation of a black deposit which is at first solid hydrogen arsenid, later elementary As. A mixture of AsH3 and 0, containing 3 vols. 0 and 2 vols. AsH3, explodes when heated, forming As2Os and H20. If the proportion of O be less, ele- mentary As is deposited. The gas burns with a greenish flame, from which a white cloud of arsenic trioxid arises. A cold surface, held above the flame, becomes coated with a white, crystalline deposit of the oxid. If the flame be cooled, by the introduction of a cold surface into it, the H alone is oxidized, and elementary As is deposited. Chlorin decomposes the gas explosively, with formation of HC1 and ar- senic trioxid. Broinin and iodin behave similarly, but with less violence. All oxidizing agents decompose it readily; H20 and arsenic tri- oxid being formed by the less active oxidants, and H20 and ar- senic acid by the more active. Solid potassium hydrate decom- poses the gas partially, and becomes coated with a dark deposit, which seems to be elementary arsenic. Solutions of the alkaline hydrates absorb and decompose it; H is given off and an alkaline ARSENIC. arsenite remains in the solution. Many metals, when heated in Ha As, decompose it with formation of a metallic arsenid and lib- eration of hydrogen. Solution of silver nitrate is reduced by it; elementary silver is deposited, and the solution contains arsenic trioxid. Although H2S and H3As decompose each other to a great ex- tent, with formation of arsenic trisulphid, in the presence of air, the two gases do not act upon each other at the ordinary temper- ature, even in the direct sunlight, either dry or in the presence of HiO, when air is absent. Hence in making H2S for use in toxico- logical analysis, materials free from As must be used; or the H2S must be purified as described on p. 92. Compounds of Arsenic and Oxygen.—Two are known: AsaOs and As205. Probably the gray substance formed by the action of moist air on elementary arsenic is a lower oxid. Arsenic trioxid—Arsenious anhydrid—Arsenions oxid—White arsenic—Arsenic—Arsenions acid—Acidum arseniosum, U. S.; Br.—Asj03—198. Preparation.—(1.) By roasting the native sulphids of arsenic in a current of air. (2.) By burning arsenic in air or oxygen. Properties.—Physical.—It occurs in two distinct forms: crys- tallized or “powdered'' and vitreous or porcelainous. When freshly fused, it appears in colorless or faintly yellow, trans- parent, vitreous masses, having no visible crystalline structure. Shortly, however, these masses become opaque upon the surface, and present the appearance of porcelain. This change, which is due to the substance assuming the crystalline form, slowly pro- gresses toward the centre of the mass, which, however, remains vitreous for a long time. The change is attended by the slow liberation of heat, and, if it be made to take place more rapidly, a faint light is visible in obscurity. When arsenic trioxid is sub- limed, if the vapors be condensed upon a cool surface, it is de- posited in the form of brilliant octahedral crystals, which are larger and more perfect the nearer the temperature of the con- densing surface is to 180° (356° F.). The crystalline variety may be converted into the vitreous, by keeping it for some time at a temperature near its point of volatilization. The taste of arsenic trioxid is at first faintly sweet, afterward somewhat acrid, metallic, and nauseating. It is odorless. In aqueous solution (see below) it has a faintly acid reaction. The sp.gr. of the vitreous variety is 3.785; that of the crystalline, 3.689. 124 MANUAL OF CHEMISTRY. Its solubility in water varies with the temperature, the method of making the solution, the presence of foreign substances and the nature of the oxid: Transparent Form. Opaque Form. Fresh Crystal- line Oxid. 1,000 parts of cold distilled water, after standing 24 hours, dissolved 1.74 parts. 1.16 parts. 2.0 parts. 1,000 parts of boiling water poured on the oxid, and allowed to stand for 24 hours, dissolved 1.000 parts of water boiled 10.12 parts. 5.4 parts. 15.0 parts. for one hour, the quan- tity being kept uniform by the addition of boil- ing water from time to time, and filtered mime- diately, dissolved 64.5 parts. 76.5 parts. 87.0 parts. The vitreous variety is more soluble than the crystalline, but, by prolonged boiling, the crystalline is converted into the vitre- ous, or, at all events, the solubility of the two forms becomes the same. The solution of the crystallized oxid in cold H20 is always very slow (the vitreous oxid dissolves more rapidly), and contin- ues for a long time. If white arsenic be thrown upon cold H20, only a portion of it sinks, the remainder floating upon the sur- face, notwithstanding its high specific gravity. This is due to a repulsion of the HaO from the surfaces of the crystals, which also accounts, to some extent at least, for its slow solution. Even after several days, cold H20 does not dissolve all the oxid with which it is in contact. If one part of oxid be digested with 80 parts of H20, at ordinary temperatures for several days, the re- sulting solution with 160 parts H20, X£T; with 240 parts, -jlo; with 1,000 parts H20, y-aVxx ; and even when 16,000 or 100,000 parts of H20 are used, a portion of the oxid remains un- dissolved. Arsenious oxid, which had remained in contact with cold H20 in closed vessels for eighteen years, dissolved to the ex- tent of 1 part in 54 of H20, or 18.5 parts in 1,000, which may be given as the maximum solubility of the crystallized oxid in cold water. The power of H20 of holding the acid in solution, once it is dissolved, is not the same as its power of dissolving it. If a concentrated solution be made, by boiling H20 upon the oxid, and filtering hot, the filtrate may be evaporated to one-half its original bulk, without depositing any of the acid, of which this concentrated fluid now contains as much as one part in six of ARSENIC. 125 H20, or 166.6 parts per 1,000. If a hot solution of the acid be al- lowed to cool, the solution will contain 62.5 parts per 1,000 at 16° (60°.8 F.), and 50 parts per 1,000 at 7° (44°.6 F.). The solubility of the oxid in alcohol varies with the strength of the spirit, and the nature of the oxid, the vitreous variety being more soluble in strong than in weak alcohol, while the contrary is the case with the crystalline, as is shown in the following table: 1,000 parts dissolve Alcohol Alcohol Alcohol Absolute at 56*. at 79*. at 86*. alcohol. Crystallized Olid Slin^int 16.80 48.95 14.30 45.51 7.15 31.97 0.25 34.02 Vitreous oxid. at 15° (59° F.) 5.04 5.40 10.60 The presence of the mineral acids and alkalies, ammonia and ammoniacal salts, alkaline carbonates, tartaric acid, and the tar- trates, increases the solubility of arsenic trioxid in water. It is less soluble in fluids containing fats, or extractive or other or- ganic matters (the various liquid articles of food), than it is in pure water. In chemico-legal cases, in which ihe question of the solubility of arsenic is likely to arise, it must not be forgotten that the quantity of As203 which a person may unconsciously take in a given quantity of fluid is not limited, uifder certain circumstances, to that which the fluid is capable of dissolving. A much greater quantity than this may be taken, while in suspension in the liquid, especially if it be mucilaginous. Chemical.—Its solutions are acid in reaction, and probably contain the true arsenious acid, H3As03. They are neutralized by bases, with formation of arsenites. Solutions of sodium or potassium hydrate dissolve it, with formation of the correspond- ing arsenite. It is readily reduced, with separation of As, when heated with hydrogen, carbon, or potassium cyanid, and at lower temperatures by more active reducing agents. Oxidizing agents, such as HN03, the hydrates of chlorin, chromic acid, convert it into arsenic pentoxid or arsenic acid. Its solution, acidulated with HC1 and boiled in presence of copper, deposits on the metal a gray film, composed of an alloy of Cu and As. Arsenic pentoxid—Arsenic anhydrid—Arsenic oxid—As206— 230—is obtained by heating arsenic acid to redness. It is a white, amorphous solid, which, when exposed to the air, slowly absorbs moisture. It is fusible at a dull red heat, and at a slightly higher temperature decomposes to As203 and O. It dissolves slowly in HoO, forming arsenic acid, H3As04. Arsenic Acids. — The oxyacids of arsenic form a series, corre- sponding to that of the oxyacids of phosphorus, except that the hvpoarsenious acid is unknown 126 MANUAL OF CHEMISTRY. /O—H 0=As—O—H > 0=As—O—H \0—H Arsenious acid: /O—H 0=As—O—H \H /O—H Pyroarsenic acid : Arsenic acid : 0=As—O—H \0—H /O—H 0=As=0 Metarsenic acid : Arsenious Acid—H3 As03—126—exists in aqueous solutions of the trioxid, although it has not been separated. Corresponding to it are important salts, called arsenites, which have the general formulae HM'2As03, HM"As03, H4M"(As03)2. Arsenic Acid—Orthoarsenic acid— HaAs04—142—is obtained by oxidizing As203 with HN03 in the presence of H20: As203-|- 2H20-f-2HN03 = 2H3As04-|-N203. A similar oxidation is also ef- fected by Cl, aqua regia, and other oxidants. A syrupy, colorless, strongly acid solution is thus obtained, which, at 15° (59° F.) becomes semi-solid, from the formation of transparent crystals, containing 1 Aq. These crystals, which are very soluble and deliquescent, lose their Aq. at 100° (212° F.), and form a white, pasty mass composed of minute white, anhydrous needles. At higher temperatures it is converted into H4As207, HAs03, and As2Os. In presence of nascent H it is decomposed into H20 and AsH3. It is reducible to H3As03 by S02. The action of H2S upon acid solutions of arsenic acid, or of the arsenates, varies with the rapidity of the action, and the temper- ature at which it occurs. With a slow current of H2S, at a low temperature, no precipitate is formed, and the solution remains colorless, under these conditions sulphoxyarsenic acid, H3As03S is formed: H3As04-)-H2S=H3AsS03-|-H20. By a further action of H2S, arsenic pentasulphid is formed: 2H3As03S-f-3H2S=As2S5 -j-6HaO. If the current of H2S be very slow, the sulphoxy- arsenic acid produced is decomposed according to the equation: 2H3As03S=As203-|-3H20-(-S, and the precipitate then produced consists of a mixture of As2S3, As2SB and S. Like phosphoric acid, arsenic acid is tribasic; and the arsenates resemble the phosphates in composition, and in many of their chemical and physical properties. Pyroarsenic acid—H4As20T—266.—Arsenic acid, when heated to 160° (320° F.), is converted into compact masses of pyroarsenic acid : 2H3As04=H4As207-|-H20. It is very prone to revert to ar- senic acid, by taking up water. Metarsenic acid—HAsOs—124.—At 200°-206° (392°-403° F.) H4 As207 gradually loses H20 to form metarsenic acid: H4As207 = 2HAsOs-fH20. It forms white, pearly crystals, which dissolve readily in H20, with regeneration of H3As04. It is monobasic. AliSENIC. 127 Compounds of Arsenic and Sulphur.—Arsenic disulphid—Red sulphid of arsenic—Realgar—Red orpiment—Ruby sulphur— Sandarach—As2S2—214—occurs in nature, in translucent, ruby- red crystals. It is also prepared by heating a mixture of As2G3 and S. As so obtained it appears in brick-red masses. It is fusible, insoluble in H20, but soluble in solutions of the alkaline sulphids, and in boiling solution of potassium hydrate. Arsenic trisulphid—Orpiment—Auripigmentum— Yellow sul- phid of arsenic—King's yellow—As2S3—246—occurs in nature in brilliant golden yellow flakes. Obtained by passing H2S through an acid solution of As203; or by heating a mixture of As and S, or of As203 and S in equivalent proportions. When formed by precipitation, it is a lemon-yellow powder, or in orange-yellow, crystalline masses, when prepared by sublima- tion. Almost insoluble in cold H20, but sufficiently soluble in hot H20 to communicate to it a distinct yellow color. By contin- ued boiling with H20 it is decomposed into H2S and As203. In- soluble in dilute HC1; but readily soluble in solutions of the alkaline hydrates, carbonates, and sulphids. It volatilizes when heated. Nitric acid oxidizes it, forming H3As()4 and H2SG4. A mixture of HC1 and potassium chlorate has the same effect. It corre- sponds in constitution to As203, and, like it, may be regarded as an anliydrid, for, although sulpharsenious acid, H3AsS3, has not been separated, the sulpharsenites, pyro- and meta-sulpliarsenites are well-characterized compounds. Arsenic pentasulphid—As2Sa—310—is formed by fusing a mix- ture of As2S3 and S in proper proportions, and, by the prolonged action of II2S, at low temperatures, upon solutions of the arsen- ates. It is a yellow, fusible solid, capable of sublimation in absence of air. There exist well-defined sulpharsenates, pyro- and rneta- sulpharsenates. Compounds of Arsenic with the Halogens.—Arsenic trifluorid— AsF3—132.—A colorless, fuming liquid, boiling at 63° (145° F.), ob- tained by distilling a mixture of As203, H2S04 and fluorspar. It attacks glass. Arsenic trichlorid—AsC13—181.5.—Obtained by distilling a mix- ture of As203, H2S04 and NaCI, using a well-cooled receiver. It is a colorless liquid, boils at 134° (273° F.), fumes when ex- posed to the air, and volatilizes readily at temperatures below its boiling-point. Its formation must be avoided in processes for the chemico-legal detection of arsenic, lest it be volatilized and lost. It is formed by the action of HC1, even when compara- tively dilute, upon As203.at the temperature of the water-bath; 128 MANUAL OF CHEMISTRY. but, if potassium chlorate be added, the trioxid is oxidized to arsenic acid, and the formation of the chlorid thus prevented. Arsenic trioxid, when fused with sodium nitrate, is converted into sodium arsenate, which is not volatile. If, however, small quan- tities of chlorids be present, AsCh is formed. It is highly poi- sonous. Arsenic tribromid—AsBr3—315.—Obtained by adding pow- dered As to Br, and distilling the product at 220° (428° F.). A solid, colorless, crystalline body, fuses at 20°-25° (68°-77° F.), boils at 220° (428° F.), and is decomposed by H20. Arsenic triiodid—Arsenii iodidum, U. S.—Asl3—456.—Formed by adding As to a solution of I in carbon disulphid; or by fusing together As and I in proper proportions. A brick-red solid, fusi- ble and volatile. Soluble in a large quantity of H20. Decom- posed by a small quantity of HuO into HI, As203, HsO and a resi- due of AsI3. Action of Arsenical Compounds upon the Animal Economy. The poisonous nature of many of the arsenical compounds has been known from remote antiquity, and it is probable that more murders have been committed by their use than by that of all other toxic substances combined. Even at the present time— notwithstanding the fact that, suspicion once aroused, the detec- tion of arsenic in the dead body is certain and comparatively easy—criminal arsenical poisoning is still quite common, espe- cially in rural districts. The poison is usually taken by the mouth, but it has also been introduced by other channels; the skin, either uninjured or abraded; the rectum, vagina and male urethra. The forms in which it has been taken are: (1.) Elementary arsenic, which is not poisonous so long as it remains such. In contact with water, or with the saliva, however, it is converted into an oxid, which is then dissolved, and, being capable of absorption, produces the characteristic effects of the arsenical compounds. Fly-paper is coated with a paste containing As, a portion of which has been oxidized by the action of air and moisture. (2.) Hydrogen ar- senid, the most actively poisonous of the inorganic compounds of arsenic, has been the cause of several accidental deaths, among others, that of the chemist Gehlen, who died in consequence of having inhaled the gas while experimenting with it. In other cases death has followed the inhalation of hydrogen, made from zinc and sulphuric acid contaminated with arsenic. (3.) Arsenic trioxid is the compound most frequently used by criminals. It has been given by every channel of entrance to the circulation; in some instances concealed with great art, in others merely held ARSENIC. 129 in suspension by stirring in a transparent fluid,, given to an in- toxicated person. If the poison have been in quantity, and un- dissolved, it may be found in the stomach after death, in the form of eight-sided crystals, more or less worn by the action of the sol- vents with which it has come in contact. The lethal dose is variable, death having occurred from two and one-half grains, and recovery having followed the taking of a dose of two ounces. It is more active when taken fasting than when taken on a full stomach, in which latter case all, or nearly all, the poison is frequently expelled by vomiting, before there has been time for the absorption of more than a small quantity. (4.) Potassium arsenite, the active substance in “ Fowler’s solu- tion,” although largely used by the laity in malarial districts as an ague-cure, has, so far as the records show, produced but few cases of fatal poisoning. (5.) Sodium arsenite is sometimes used to clean metal vessels, a practice whose natural results are exem- plified in the death of an individual who drank beer from a pew- ter mug so cleaned; and in the serious illness of 340 children in an English institution, in which this material had been used for cleaning the water-boiler. (6.) Arsenic acid and arsenates.—The acid itself has, so far as we know, been directly fatal to no one. The cases of death and illness, however, which have been put to the account of the red anilin dyes, are not due to them directly, but to arsenical residues remaining in them as the result of de- fective processes of manufacture. (7.) Sulphids of arsenic.—Poison- ing by these is generally due to the use of orpiment, introduced into articles of food as a coloring matter, by a combination of fraud and stupidity, in mistake for turmeric. (8.) The arsenical greens.—Scheele’s green, or cupric arsenite, and Schweinfurth green, or cupric aceto-metarsenite (the latter commonly known in the United States as Paris green, a name applied in Europe to one of the anilin pigments). These substances, although rarely administered with murderous intent, have been the cause of death in a great number of cases. Among suicides in the lower orders of the population in large cities, Paris green has been the favorite. The arsenical pigments may also produce disastrous results by “accident;” by being incorporated in ornamental pieces of con- fectionery; by being used in the dyeing of textile fabrics, from which they may be easily rubbed off; from their use for the de- struction of insects, and by being used in the manufacture of wall-paper. Many instances of chronic or subacute arsenical poi- soning have resulted from inhabiting rooms hung with paper whose whites, reds, or greens were produced by arsenical pig- ments. From such paper the poison is disseminated in the at- mosphere of the room in two ways: either as an impalpable pow- der, mechanically detached from the paper and floating in the MANUAL OF CHEMISTRY. air, or by their, decomposition, and the consequent diffusion of volatile arsenical compounds in the air. The treatment in acute arsenical poisoning is the same, whatever may be the form in which the poison has been taken, if it have been taken by the mouth. The first indication is the removal of any unabsorbed poison from the alimentary canal. If vomiting have not occurred from the effects of the toxic, it should be in- duced by the administration of zinc sulphate, or by mechanical means. The stomach-pump should not be used unless the case is seen soon after the taking of the poison. When the stomach has been emptied, the chemical antidote is to be administered, with a view to the transformation, in the stomach, of any remaining arsenical compound into the insoluble, and therefore innocuous, ferrous arsenate. To prepare the antidote, a solution of ferric sulphate, Liq. ferri tersulphatis (U. S,)=Liq. ferri persulphatis (Br.) is diluted with three volumes of water, and treated with aqua ammonias in slight excess. The precipitate formed is col- lected upon a muslin filter, and washed with water until the Avashings are nearly tasteless. The contents of the filter—Ferri oxidum hydratum (U. S.), Ferri per oxidumhumidum (Br.) are to be given moist, in repeated doses of one to two teaspoonfuls, until an amount of the hydrate equal to 20 times the Aveight of Avliite arsenic taken has been administered. Dialyzed iron may be given Avhile the hydrate is in preparation, or AArhen the mate- rials for its preparation are not obtainable. Precautions to be taken by the Physician in cases of suspected Poisoning. It will rarely happen that in a case of suspected homicidal poi- soning by arsenic, or by other poisons, the physician in charge will be willing or competent to conduct the chemical analysis, upon which, probably, the conviction or acquittal of the accused will mainly depend. Upon his knowledge and care, however, the success or futility of the chemist’s labors depends in a great measure. It is, as a rule, the physician who first suspects foul play; and, while it is undoubtedly his duty to avoid any public manifesta- tion of his suspicion, it is as certainly his duty toward his patient and toward the community, to satisfy himself as to the truth or falsity of his suspicion by the application of a simple test to the excreta of the patient during life, the result of which may enable him to prevent a crime, or, failing that, take the first step toward the punishment of the criminal. In a case in which, from the symptoms, the physician suspects poisoning by any substance, he should himself test the urine or AESENIC. 131 faeces, or both, and govern his treatment and his actions toward the patient, and those surrounding the patient, by the results of his examination. Should the case terminate fatally, he should at once communicate his suspicions to the prosecuting officer, and require a post-mortem investigation, which should, if at all pos- sible, be conducted in the presence of the chemist who is to con- duct the analysis. For, be the physician as skilled as he may, there are odors and appearances, observable in many cases at the opening of the body, full of meaning to the toxicological chemist, which are ephemeral, and whose bearing upon the case is not readily recognized by those not thoroughly experienced. Cases frequently arise in which it is impossible to bring the chemist upon the ground in time for the autopsy. In such cases the physician should remember that that portion of the poison remaining in the alimentary tract (we are speaking of true poi- sons) is but the residue of the dose in excess of that which has been necessary to produce death; and, if the processes of elimina- tion have been active, there may remain no trace of the poison in the alimentary canal, while it still may be detectable in deeper- seated organs. The poison may also have been administered by another channel than the mouth, in which event it may not reach the stomach. For these reasons it is not sufficient to send the stomach alone for analysis. The chemist should also receive the entire intestinal canal, at least one-half the liver, the spleen, one or both kidneys, a piece of muscular tissue from the leg, the brain, and any urine that may remain in the bladder. The intestinal canal should be removed and sent to the chemist without having been opened, and with ligatures, enclosing the contents, at the two ends of the stomach, and at the lower end of the intestine. The brain and alimentary canal are to be placed in separate jars, and the other viscera in another jar together; the urine in a vial by itself. All of these vessels are to be new and clean, and are to be closed by new corks, or by glass stoppers, or covers (not zinc screw-caps), which are then coated with paraffin (not sealing-wax), and so fastened with strings and seals, that it is impossible to open the vessels without cutting the strings, or breaking the seals. Any vomited matters are to be preserved. If the physician fail to ob- serve these precautions, he has probably made the breach in the evidence through which the criminal will escape, and has at the outset defeated the aim of the analysis. Analytical Characters of the Arsenical Compounds.—Arsenious Compounds.—(1.) H2S, a yellow color in neutral or alkaline liquids; a yellow ppt. in acid liquids. The ppt. dissolves in solutions of the alkaline hydrates, carbonates, and sulphvdrates; but is scarcely affected by HC1. Hot HNOa decomposes it. 132 MANUAL OF CHEMISTRY. (2.) AgN03, in the presence of a little NH4HO, gives a yellow ppt. This test is best applied by placing the neutral arsenical solution in a porcelain capsule, adding neutral solution of AgNCb, and blowing upon it over the stopper of the NH4HO bottle, moist- ened with that reagent. (3.) CuS04 under the same conditions as in (2) gives a yellowish- green ppt. (4.) A small quantity of solid As203 is placed in the point a of the tube, Fig. 32; above it, at 5, a splinter of recently ignited charcoal; b is first heated to redness, then a ; the vapor of As203, passing over the hot charcoal, is reduced, and elementary As is deposited at c in a metallic ring. The tube is then cut between b and c, the larger piece held with d uppermost and heated at e; Fia. 32. the deposit is volatilized, the odor of garlic is observed, and bright, octahedral crystals (Fig. 34), appear in the cool part of the tube. (5.) Reinsch test.—The suspected liquid is acidulated with one- sixth its bulk of HC1. Strips of electrotype copper are immersed in the liquid, which is boiled. In the presence of an arsenious compound, a gi-ay or bluish deposit is formed upon the Cu. A similar deposit is produced by other substances (Bi, Sb, Hg). To complete the test the Cu is removed, washed, and dried between folds of filter-paper, without removing the deposit. The copper, with its adherent film, is rolled into a cylinder, and introduced into a dry piece of Bohemian tubing, about i inch in diameter and six inches long, which is held at the angle shown in Fig. 33 and heated at the point containing the copper. If the deposit consist of arsenic, a white deposit is formed at a, which contains brilliant specks, and, when examined with a magnifier, is found to consist of minute octahedral crystals, Fig. 34. The advantages of this test are: it may be applied in the pres- ence of organic matter, to the urine for instance; it is easily con- ARSENIC. 133 ducted; and its positive results are not misleading, if the test be carried to completion. These advantages render it the most suit- able method for the physician to use, during the life of the pa- tient. It should not be used after death by the physician, as by Fig. 33. Fig. 34. it copper is introduced into the substances under examination, which may subsequently interfere seriously with the analysis. The purity of the Cu and HC1 must be proved by a blank testing before use. Reinscli's test is not as delicate as Marsh’s, and it only reacts slowly and imperfectly when the arsenic is in the higher stage of oxidation, or in presence of oxidizing agents. (6.) Marsh’s test is based upon the formation of AsH3 when a reducible compound of arsenic is in presence of nascent H; and Fig. 35. the subsequent decomposition of the arsenical gas by heat, with separation of elementary arsenic. The apparatus used (Fig. 35) consists of a glass generating ves- sel a, of about 150 c.c. capacity (5 fl §), into whose upper opening 134 MANUAL OF CHEMISTRY. a funnel tube c is either ground, or fitted by a section of rubber tube. The lateral outlet is connected with a tube d, filled with fragments of calcium chlorid; which in turn connects with the Bohemian glass tube gy, which should be about 0.5 cent, in diam- eter, and about 80 cent. long. This tube is protected by a tube of wire gauze, within which it is adjusted in the furnace as shown in the figure. The other end of gg is bent downward, and dips into a solution of silver nitrate in the test-tube/. The vessel a is first charged with about 25 grams (6f 3 ) of pure granulated zinc, which has been in contact with a diluted solu- tion of platinic chlorid for half an hour, and then washed. The apparatus is then connected in .such a manner that all joints are gas-tight, and the funnel-tube c about half filled with H2S04, diluted with an equal bulk of H20, and cooled. By opening the stopcock, the acid is brought in contact with the zinc in small quantities, in such a manner that during the entire testing bub- bles of gas pass through/, at the rate of 60-80 per minute. After fifteen minutes the burner is lighted, and the heating continued, during evolution of gas from zinc and H«S04, for an hour. At the end of that time, if no stain have formed in g beyond e, then zinc and acid may be considered pure and the suspected solution, prepared as described on page 137, introduced slowly through the funnel-tube. If arsenic be present in the substance examined, a hair-brown or gray deposit is formed in the cool part of g beyond e. At the same time the contents of / are darkened if the amount of As present is so great that all the AsH3 produced is not decomposed in the heated portion of gg. To distinguish the stains produced by arsenical compounds from the similar ones produced by antimony the following differ- ences are noted: The Arsenical Stain. The Ailtimonial Stain. First. — Is farther removed from the heated portion of the tube, and, if small in quantity, is double—the first liair-brown, the second steel-gray. First. — Is quite near the heated portion of the tube. Second. — Volatilizes readily when heated in an atmosphere of hydrogen, being deposited farther along in the tube. The escaping gas has the odor of garlic. Second.—Requires a much higher temperature for its vola - tilization ; fuses before volatil- izing. Escaping gas has no al- liaceous odor. Third. — When cautiously heated in a current of oxygen, brilliant, white, octahedral crys- tals of arsenic trioxid are depos- ited farther along in the tube. Third.—No crystals formed by heating in oxygen. ARSENIC. 135 The Arsenical Stain. The Antimonial Stain Fourth.—Instantly soluble in solution of sodium hypochlor- ite. Fourth. — Insoluble in solu- tion of sodium hypochlorite. Fifth.—Slowly dissolved by solution of ammonium sulphy- drate; more rapidly when warmed. Fifth.—Dissolves quickly in solution of ammonium sulphy- drate. Sixth.— The solution ob- tained in 5 leaves, on evapora- tion over the water-bath, a bright yellow residue. Sixth. —The solution ob- tained in 5 leaves, on evapo- ration over the water-bath, an orange-red residue. Seventh.—The residue ob- tained in 6 is soluble in aqua aminoniae, but insoluble in hy- drochloric acid. Seventh.—The residue ob- tained in 6 is insoluble in aqua ammonias, but soluble in hy- drochloric acid. Eighth.—Is soluble in warm nitric acid; the solution on evaporation yields a white resi- due, which turns brick-red when moistened with silver ni- trate solution. Eighth.—Is soluble in warm nitric acid; the solution on evaporation yields a white resi- due, which is not colored when moistened with silver nitrate solution. Ninth.—Is not dissolved by a solution of stannous chlorid. Ninth. — Dissolves slowly in solution of stannous chlorid. If, however, the process described on p. 136 have been followed, there can be no antimony in the liquid which would contain ar- senic, if present. The silver solution in / is tested for arsenious acid, by floating upon its surface a layer of diluted NH4HO solu- tion, which, in the presence of arsenic, produces a yellow (not brown) band, at the point of junction of the two liquids. In place of bending the tube gg' downward, it may be bent up- ward and drawn out to a fine opening. If the escaping gas be then ignited, the heating of the tube being discontinued, a white deposit of As-jOa may be collected on a glass surface held above the flame; or a brown deposit of elementary As upon a cold (porcelain) surface held in the flame. In place of generating nascent hydrogen by the action of Zn on H2SO4, it may be produced by the decomposition of acidulated H„»0 by the battery, in a Marsh apparatus especially modified for that purpose. In another modification of the Marsh test the AsH3 is decom- posed, not by passage through a red-hot tube, but by passing through a tube traversed by the spark from an induction coil. (7.) Fresenius’ and von Babo’s test.—The sulphid, obtained in (1), is dried, and mixed with 12 parts of a dry mixture of 3 pts. sodium carbonate and 1 pt. potassium cyanid, and the mixture brought into a tube, drawn out to a fine opening, through which a slow current of C0-2 is allowed to pass. The tube is then heated to redness at the point containing the mixture, when, if MANUAL OF CHEMIST11Y. arsenic be present, a gray deposit is formed at the constricted portion of the tube; which has the characters of the arsenical stain indicated on pp. 134, 135. (8.) Place a small crystal of sodium sulphite in a solution of 0.3-0.4 gram of stannous chlorid in pure HC1, sp. gr. 1.13. Float the liquid to be tested on the surface of this mixture. If As be present a yellow band is formed at the junction of the two liquids, and gradually increases upward. Arsenic Compounds—(1.) HUS does not form a ppt. in neu- tral or alkaline solutions. In acid solutions a yellow ppt., con- sisting either of AS2S3 or As2S5, or a mixture of the sulphids with free S, is formed only after prolonged passage of H2S at the or- dinary temperature, more rapidly at about 70° (158° F.). (2.) AgNOs, under the same conditions as with the arsenious com- pounds, produces a brick-red ppt. of silver arsenate. (3.) CuSCh under like circumstances produces a bluish-green ppt. Arsenic compounds behave like arsenious compounds with the tests 4, 6 and 7 for the latter. Method of Analysis for Mineral Poisons.—In cases of suspected poisoning a systematic course of analysis is to be followed by which the presence or absence of all the more usual poisons can be determined. In the search for mineral poisons (see alkaloids), the first step is the destruction of organic matter. To this end the material to he examined, if liquid, is concentrated, and, if solid, is divided into small pieces and suspended in H20. About the volume of concentrated HC1, and a small quantity of potassium chlorate are added, and the mixture allowed to stand 24 hours at the ordi- nary temperature, in a porcelain capsule covered by a glass plate. The contents of the capsule are then heated over the water-bath, while potassium chlorate, in small quantities, and, if necessary, HC1, are added from time to time, and the mixture is occasionally stirred, and lumps of solid matter crushed with a flattened glass rod, until the mass has a uniform light-yellow color. If the liquid smell strongly of Cl, C02 is passed through it. When the odor of Cl has disappeared, the liquid is filtered, and the residue washed with hot water. If a deposit form on cooling, the liquid is again filtered. The clear filtrate and washings, if strongly acid, five partially neutralized with sodium carbonate, and treated with H2S; the gas being passed slowly through the liquid for about half an hour at a time, at intervals of 4-G hours, during 3 days; the vessel being well corked during the intervals. The precipitate formed, which may contain Sn, As, Sb, Hg, Pb, Bi or Cu, is collected on a filter, and washed with H20, containing a small quantity of H2S, until the washings fail to give the faintest cloudiness when boiled, acidulated with HN()3 and treated with silver nitrate. Solution of ammonium sulphydrate is added to the precipitate on the filter, which is then washed with water. The solution passing through may contain As, Sb, Sn and Cu; the residue on ANTIMONY. 137 the filter (A) may contain Hg, Pb, Bi and Cu. The solution is evaporated over the water-bath to dryness, and the residue moist- ened with fuming HAU3, dried, moistened with HaO, and dried several times, and then, after neutralization with caustic soda, fused with a mixture of sodium carbonate and nitrate, until it is colorless, or contains only a black, granular deposit, the heat being slowly increased. The cooled residue of fusion is dissolved in a small quantity of warm HaO, and CC2 is passed through the solution, whether it be clear or cloudy. The solution, if not per- fectly clear, is filtered. Any deposit retained by the filter (B) may contain Sn, Sb or Cu. The filtrate is strongly acidulated with HjSOi, and slowly evaporated and heated, with addition of more H2SC>4, if necessary, until abundant white fumes are given off. The cooled residue, which may contain As, is dissolved in H2G, and introduced into the Marsh apparatus when cold. The residue B, if black, is dissolved in hot HN03, and the solu- tion tested for Cu. If it be white, it is ignited, with the filter, in a porcelain crucible; fused with potassium cyanid; and washed with H20. The residue is extracted with warm HC1, and the solution tested for Sn. If any residue remain, it is extracted with HC1, to which a few drops of HN03 have been added, and the solution tested for Sb. The residue A, after washing, is boiled with HN03, diluted with H20 and filtered. The filtrate is tested for Cu, Bi and Pb. The residue, if any, is tested for Hg and Pb. ANTIMONY. Symbol=Sb (Latin, stibium)—Atomic weight=120—Molecular weight=240 (?)—Sp. yr. =6.175—Fuses at 450° (842° F.). Occurrence.—Free in small quantity; principally in the trisul- phid, Sb2S3. Preparation.—The native sulphid (black, or crude antimony) is roasted, and then reduced, by heating with charcoal. The com- mercial antimony so obtained may be purified by fusing a mix- ture of antimony, 10 pts.; native sulphid of antimony, 1 pt.; and dry sodium carbonate, 2 pts. After cooling, the button is pow- dered, and fused with 1+ pts. sodium carbonate and 1% ferrous sulphid. The antimony is again separated, powdered, and fused with sodium carbonate and a small quantity of sodium nitrate. Each fusion is maintained for an hour. Properties.—Physical.—A bluish-gray, brittle solid, having a metallic lustre; readily crystallizable; tasteless and odorless; volatilizes at a red heat, and may be distilled in an atmosphere of H. Chemical.—Is not altered by dry or moist air at ordinary tem- peratures. When sufficiently heated in air, it burns, with forma- tion of Sb203, as a white, crystalline solid. It also combines directly with Cl, Br, I, S, and many metallic elements. It com- bines with H under the same circumstances as does As. Cold, 138 MANUAL OF CHEMISTRY. dilute H2S04 does not affect it; the hot, concentrated acid forms with it antimonyl sulphate, (Sb0)2S04 and S02. Hot HC1 dis- solves it, when finely divided, with evolution of H. It is readily oxidized by HNOs, with formation of H3Sb04 or Sb204. Aqua regia dissolves it as SbCl3, or SbCl5. Solutions of the alkaline hydrates do not act on it. The element itself does not form salts with the oxyacids. There are, however, compounds, formed by the substitution of the group antimonyl (SbO), for the basic hydrogen of those acids. (See tartar emetic.) It enters into the composition of type metal, antifriction metals, and britannia metal. Hydrogen Antimonid—Antimoniuretted hydrogen—Stibamin —Stibonia—Stibin—SbH3—123.—It has not been obtained in a condition of purity, but is produced, mixed with H, when a reduci- ble compound of Sb is in presence of nascent H. It is obtained in larger amount, by decomposing an alloy of 400 parts of a 2% so- dium amalgam, and 8 parts of freshly reduced, and dried Sb, by H20, in a current of C02. It is a colorless, odorless, combustible gas, subject to the same decomposition? as AsH3; from which it differs in being by no means as poisonous, and in its action upon silver nitrate solu- tion. The arsenical gas acts upon the silver salt according to the equation: 6AgN03+AsH3-|-3H20=GHN03-{-HsAsC)3-|-3Ag2, and the precipitate formed is elementary silver, while H3As03 re- mains in the solution. In the case of SbHs the reaction is 3AgZS"03 -j-SbH3=3HNOs+SbAg3, all of the Sb being precipitated in the black silver antimonid. Compounds of Antimony and Oxygen.—Three are known, Sb203, Sb204 and Sb205. Antimony trioxid—Antimonous anhydrid—Oxid of antimony —Antimonii oxidum (U. S.; Br.)—Sb203—288—occurs in nature; and is prepared artificially by decomposing the oxyclilorid; or by heating Sb in air. It is an amorphous, insoluble, tasteless, odorless powder; white at ordinary temperatures, but yellow when heated. It fuses readily, and may be distilled in absence of oxygen. Heated in air, it burns like tinder, and is converted into Sb204. It is reduced, v'itli separation of Sb, when heated with char- coal, or in H. It is also readily oxidized by HN03, or potassium permanganate. It dissolves in HC1 as SbCl3; in Nord hausen sul- phuric acid, from which solution brilliant crystalline plates of antimonyl pyrosulphate, (Sb0)2S207, separate; and in solutions of tartaric acid, and of hydropotassic tartrate (see tartar emetic). ANTIMONY. Boiling solutions of alkaline hydrates convert it into antinionic acid. Antimony pentoxid—Antimonic anhydr 'ul—Sb206—320—is ob- tained by heating metantimonic acid to dull redness. It is an amorphous, tasteless, odorless, pale lemon-yellow colored solid; very sparingly soluble in water and in acids. At a red heat it is decomposed into Sb204 and O. Antimony antimoniate—Intermediate oxid—Diantimonic te- troxid—Sb204—304—occurs in nature, and is formed when the oxids or hydrates of Sb are strongly heated, or when the lower stages of oxidation or the sulphids are oxidized by HN()3, or by fusion with sodium nitrate. It is insoluble in H20; but is decom- posed by HC1, hydropotassic tartrate, and potash. Antimony Acids.—The normal antiinonous acid, H3Sb03, cor- responding to H3P03, is unknown; but the series of antimonic acids: ortho—H3Sb04, pyro—H4Sb20-, and meta—HSbC)3, is com- plete, either in the form of salts, or in that of the free acids. There also exists, in its sodium salt, a derivative of the lacking antiinonous acid: metantimonous acid, HSb02. The compound sometimes used in medicine under the name washed diaphoretic antimony is potassium metantimonate, uni- ted with an excess of the pentoxid: 2KSb03, Sb205. The hydro- potassic pyroantiinonate, K2H2Sb207,6Aq is a valuable reagent for the sodium compounds. It is obtained by calcining a mixture of one part of antimony with four parts of potassium nitrate, and fusing the product with its own weight of potassium carbonate. Chlorids of Antimony.—Antimony trichlorid—Protochlorid or butter of antimony—SbCl3—226.5—is obtained by passing dry Cl over an excess of Sb2S3; by dissolving Sb2S3 in HC1; or by distil- ling mixtures, either of Sb2S3 and mercuric chlorid, or of Sb and mercuric chlorid, or of antimonyl pyrosulpliate and sodium chlorid. At low temperatures it is a solid, crystalline body; at the ordi- nary temperature a yellow, semi-solid mass, resembling butter; at 73°.2 (164’ F.) it fuses to a yellow, oily liquid, which boils at 223’ (433°.4 F.). Obtained by solution of Sb2S3 in HC1 of the usual strength, it forms a dark yellow solution, which, when con- centrated to sp. gr. 1.47, constitutes the Liq. Antimonii chloridi (Sr.). It absorbs moisture from air, and is soluble in a small quantity of H20; with a larger quantity it is decomposed, with precipita- tion of a white powder, powder of Algaroth, whose composition is SbOCl if cold H20 be used, and Sb405Cl2 if the H20 be boiling. In II20 containing 15 per cent, or more HC1, SbCl3 is soluble with- out decomposition. 140 MANUAL OF CHEMISTRY. Antimony pentachlorid—SbCl5—297.5—is formed by the action of Cl, in excess, upon Sb or SbCl3, and purified by distillation, in a current of Cl. It is a fuming, colorless liquid, which solidifies at —20° (—4° F.), the solid fusing at —6° (21°.2 F.). It absorbs moisture from air. With a small quantity of H20, and by evaporation over H2S04, it forms a hydrate, SbCl64H20, which appears in transparent, deliquescent crystals. With more H20, a crystalline oxychlorid, SbOCl3, is formed; and with a still greater quantity, a white pre- cipitate of orthoantimonic acid, H3Sb04. Sulphids of Antimony.—Antimony trisulphid—Sesquisulphid of antimony—Black antimony— Antimonii sulphidum (U. S.)— Antimonium nigrum (Br.)—Sb2S3—336—is the chief ore of anti- mony; and is formed when H2S is passed through a solution of tartar emetic. The native sulphid is a steel-gray, crystalline solid; the artifi- cial product, an orange-red, or brownish-red, amorphous powder. The crude antimony of commerce is in conical loaves, prepared by simple fusion of the native sulphid. It is soft, fusible, readily pulverized, and has a bright metallic lustre. Heated in air, it is decomposed into S02 and a brown, vitreous, more or less transparent mass, composed of varying proportions of oxid and oxysulphids, known as crocus, or liver, or glass of antimony. Sb2S3 is an anhydrid, corresponding to which are salts known as sulphantimonites, having the general formula M'2HSbS3. If an excess of Sb2S3 be boiled with a solution of pot- ash or soda, a liquid is obtained, which contains an alkaline sul- phantimonite, and an excess of Sb2S3. If this solution be filtered, and decomposed by an acid while still hot, an orange-colored, amorphous precipitate is produced, which is the antimonium sul- phuratum (U. S. ; Br.), and consists of a mixture, in varying pro- portions, of Sb2S3 and Sb203. If, however, the solution be al- lowed to cool, a brown, voluminous, amorphous precipitate separates, which consists of antimony trisulphid and trioxid, potassium or sodium sulphid, and alkaline sulphantimonite in varying proportions; and is known as Kermes mineral. If now the solution from which the Kermes has been separated, be de- composed with II2S04, a reddish-yellow substance separates, which is the golden sulphuret of antimony, and consists of a mix- ture of Sb2S3 and Sb2S5. The precipitate obtained when H2S acts upon a solution of an antimonial compound is, according to cir- cumstances, Sb2S3 or Sb2S5, mixed with free S. By the action of IICl on Sb2S3, II2S is produced. Antimony pentasulphid—Sb2S5—400—is obtained by decompos- ing an alkaline sulphantimonate by an acid. It is a dark orange- ANTIMONY. 141 red, amorphous powder, readily soluble in solutions of the alkalies, and alkaline sulphids, with which it forms sulphantimonates. An oxysulphid, SbeSeCb, is obtained by the action of a solution of sodium hyposulphite upon SbCla or tartar emetic. It is a fine red powder, used as a pigment, and called antimony cinnabar or antimony vermilion. Action of Antimony Compounds on the Economy.—The com- pounds of antimony are poisonous, and act with greater or less energy as they are more or less soluble. The compound which is most frequently the cause of antimonial poisoning is tartar emetic (q. v.), which has caused death in a dose of half a grain, although recovery has followed the ingestion of half an ounce in several instances. Indeed, the chances of recovery seem to be better with large, than with small doses, probably owing to the more rapid and complete removal of the poison by vomiting with large doses. Antimonials have been sometimes criminally admin- istered in small and repeated doses, the victim dying of exhaus- tion. In such a case an examination of the urine will reveal the cause of the trouble. If vomiting have not occurred in cases of acute antimonial poi- soning it should be provoked by warm water, or the stomach should be evacuated by the pump. Tannin in some form (decoc- tion of oak bark, cinchona, nutgalls, tea) should then be given, with a view to rendering any remaining poison insoluble. Medicinal antimonials are very liable to contamination with arsenic. Analytical characters of Antimonial Compounds.—(1.) With H3S in acid solution, an orange-red ppt., soluble in NH4HS and in hot HC1. (2.) A strip of bright copper, suspended in a boiling solution of an Sb compound, acidulated with HC1, is coated with a blue-gray deposit. This deposit when dried (on the copper), and heated in a tube, open at both ends yields a white, amorphous sublimate (see No. 5, p. 132). (3.) Antimonial compounds yield a deposit by Marsh’s test, sim- ilar to that obtained with arsenical compounds, but differing in the particulars given above (see No. 6, p. 134). If, in cases of suspected poisoning, the examination have been conducted as directed on p. 136, any Sb present is separated dur- ing the fusion with sodium nitrate and carbonate, and the subse- quent solution and filtration, so completely that As and Sb can- not be mistaken for one another. 142 MANUAL OF CHEMISTRY. IV.—BORON GROUP. BORON. Symbol='B—Atomic weight—\\—Molecular weight=22 (i)=Iso- lated by Davy in 1807. Boron constitutes a group by itself; it is trivalent in all of its compounds; it forms but one oxid, which is the anhydrid of a tribasic acid; and it forms no compound with H. It is separable in two allotropic modifications. Amorphous boron is prepared by decomposition of the oxid, by heating with metallic potassium or sodium. It is a greenish-brown powder; sparingly soluble inH20; infusible, and capable of direct union with Cl, Br, O, S, and N. Crystallized boron is produced when the oxid, chlorid or fluorid is reduced by Al. It crystallizes in quadratic prisms; more or less transparent, and varying in color from a faint yellow to deep garnet-red; very hard; sp. gr. 2.68. It burns when strongly heated in O, and readily in Cl; it also combines with N, which it is ca- pable of removing from NHa at a high temperature. Boron trioxid—Boric or boracic anhydrid—B203—70—is ob- tained by heating boric acid to redness in a platinum vessel. It is a transparent, glass-like mass, used in blowpipe analysis under the name vitreous boric acid. Boric Acids.—Boric acid—Boracic acid—Acidum boricum (U. S.)—H3B03—62—occurs in nature; and is prepared by slowly de- composing a boiling, concentrated solution of borax, with an ex- cess of H2SO4, and allowing the acid to crystallize. It forms brilliant crystalline plates, unctuous to the touch; odorless; slightly bitter; soluble in 25 parts H20 at 10° (50 F.); soluble in alcohol. Its solution reddens litmus, but turns tur- meric paper brown. When its aqueous solution is distilled, a portion of the acid passes over. Boric acid readily forms ethers with the alcohols. When heated with ethylic alcohol, ethyl borate is formed, which burns with a green flame. Heated with glycerin a soluble, neutral ether is formed, known as boroglycerid, and used as an antiseptic. If H3BO3 be heated for some time at 80° (176° F.), it loses H20 and is converted into metaboric acid, HB02. If maintained at 100° (212' F.) for several days, it loses a further quantity of H20, and is converted into tetraboric or pyroboric acid, H2B40t, whose sodium salt is borax. CARBON. 143 V.—CARBON GROUP. Carbon—Silicon. The elements of this group are bivalent or quadrivalent. The saturated oxid of each is the anhydrid of a dibasic acid. They are both combustible, and each occurs in three allotropic forms. CARBON. Symbol—C—Atomic weight—12—Molecular weight—24 (?). Occurrence.—Free in its three allotropic forms: The diamond in octahedral crystals; in alluvial sand, clay, sandstone and con- glomerate; graphite, in amorphous or imperfectly crystalline forms; amorphous, in the different varieties of anthracite and bi- tuminous coal, jet, etc. In combination, it is very widely distrib- uted in the so-called organic substances. Properties.—Diamond.—The crystals of diamond, which is al- most pure carbon, are usually colorless or yellowish, but may be blue, green, pink, brown or black. It is the hardest substance known, and the one which refracts light the most strongly. Its index of refraction is 2.47 to 2.75. It is very brittle; a bad con- ductor of heat and of electricity; sp. gr. 3.50 to 3.55. When very strongly heated in vacuo, it swells up, and is converted into a black mass, resembling coke. Graphite is a form of carbon almost as pure as the diamond, capable of crystallizing in hexagonal plates; sp. gr. 2.2; dark gray in color; opaque; soft enough to be scratched by the nail; and a good conductor of electricity. It is also known as black lead or plumbago. It has been obtained artificially, by allowing molten cast-iron, containing an excess of carbon, to cool slowly, and dissolving the iron in HC1. Amorphous carbon is met with in a great variety of forms, nat- ural and artificial, in all of which it is black; sp. gr. l.G-2.0; more or less porous; and a conductor of electricity. Anthracite coal is hard and dense; it does not flame when burn- ing; is difficult to kindle, but gives great heat with a suitable draught. It contains 80-90 per cent, of carbon. Bituminous coal differs from anthracite in that, when burning, it gives off gases, which produce a flame. Some varieties are quite soft, while others, such as jet, are hard enough to assume a high polish. It is usually compact in texture, and, very frequently, contains im- pressions of leaves, and other parts of plants. It contains about 75 per cent, of carbon. Charcoal, carbo ligni, U. S., is obtained by burning woody fibre, 144 MANUAL OF CHEMISTRY. with an insufficient supply of air. It is brittle and sonorous; has the form of the wood from which it was obtained, and retains all the mineral matter present in the woody tissue Its sp. gr. is about 1.57. It has the power of condensing within its pores odor- ous substances, and large quantities of gases; 90 volumes of am- monia, 55 of hydrogen sulphid, 9.25 of oxygen. This property is taken advantage of in a variety of ways. Its power of absorbing odorous bodies renders it valuable as a disinfecting, and filtering agent, and in the prevention of putrefaction and fermentation of certain liquids. The efficacy of charcoal as a filtering material is due also, in a great measure, to the oxidizing action of the oxygen condensed in its pores; indeed, if charcoal be boiled with dilute IIC1, dried, and heated to redness, the oxidizing action of the oxygen, which it thus condenses, is very energetic. Lamp-black is obtained by incomplete combustion of some res- inous or tarry substance, or natural gas, the smoke or soot from which is directed into suitable condensing-chambers. It is a light, amorphous powder, and contains a notable quantity of oily and tarry material, from which it may be freed by heating in a cov- ered vessel. It is used in the manufacture of printer’s ink. Coke is the substance remaining in gas-retorts, after the distil- lation of bituminous coal, in the manufacture of illuminating gas. It is a hard, grayish substance, usually very porous, dense, and sonorous. When iron retorts are used, a portion of the gaseous products are decomposed by contact with the hot iron surface, upon which there is then deposited a layer of very hard, compact, grayish carbon, which is a good conductor of electricity, and fur- nishes the best material for making the carbons of galvanic bat- teries and the points for the electric light. It does not form when gas is made in clay retorts. Animal charcoal is obtained by calcining animal matters in closed vessels. If prepared from bones it is known as bone-black, carbo animalis, U. S.; if from ivory, ivory black. The latter is used as a pigment, the former as a decolorizing agent. Bones yield about 00 per cent, of bone-black, which contains, besides carbon, nitrogen and the phosphates and other mineral sub- tances of the bones. It possesses in a remarkable degree the power of absorbing coloring matters. When its decolorizing power is lost by saturation with pigmentary bodies, it may be restored, although not completely, by calcination. For certain purposes purified animal charcoal, i.e., freed from mineral mat- ter, carbo animalis purificatus, TJ. S., is required, and is obtained by extracting the commercial article with HC1, and washing it thoroughly. Its decolorizing power is diminished by this treat- ment. Animal charcoal has the power of removing from a solu- tion certain crystalline substances, notablv the alkaloids, and a SILICON. 145 method has been suggested for separating these bodies from organic mixtures by its use. All forms of carbon are insoluble in any known liquid. Chemical.—All forms of C combine with O at high temperatures, with light and heat. The product of the union is carbon dioxid if the supply of air or O be sufficient; but if O be present in lim- ited quantity, carbon monoxid is formed. The affinity of C for O renders it a valuable reducing agent. Many metallic oxids are reduced, when heated with C, and steam is decomposed when passed over red-hot C: H20-f-C=C0-|-H2. At elevated tempera- tures C also combines directly with S, to form carbon disulpliid. With H, carbon also combines directly, under the influence of the voltaic arc. For Compounds of Carbon see page 222, SILICON. Symbol=Si—Atomic weight—28—Molecular weight=5Q (?)—Bis- covered by Davy 1807—Name f rom silex=flint. Also known as silicium; occurs in three allotropic forms: Amor- phous silicon, formed when silicon chlorid 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 dioxid. It dis- solves in potash and in hydrofluoric acid, but is not attacked by other acids. Graphitoid silicon is obtained by fusing potassium fluosilicate with aluminium. It forms hexagonal 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 dia- mond, 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 com- paratively few compounds. It has been caused to form artificial combinations, however, which indicate its possible capacity to exist in substances, corresponding to those C compounds com- monly known as organic, e.g., silicichloroform and silicibromo- form, SiHCh and SiHBr3. Hydrogen silicid—SiH,—32—is obtained as a colorless, insolu- ble, spontaneously inflammable gas, by passing the current of a galvanic battery of twelve cells through a solution of common salt, using a plate of aluminium, alloyed with silicon, as the posi- tive electrode. Silicon chlorid—SiCl4—170—a colorless, volatile liquid, having 146 MANUAL OF CHEMISTRY. an irritating odor; sp. gr. 1.52; boils at 59° (138°.2 F.); formed when Si is heated to redness in Cl. Silicic oxid—Silicic anhydrid—Silex—Si02—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 contain- ing that mineral, in agate, carnelian, flint, etc. Its purest native form is rock crystal. Its hydrates occur in the opal, and in solu- tion in natural waters. When crystallized, it is fusible with diffi- culty. When heated to redness with the alkaline carbonates it forms silicates, which solidify to glass-like masses, on cooling. It unites with H20 to form a number of acid hydrates. The nor- mal hydrate, H4Si04, 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 water and in acids and alkalies, is obtained by adding a small quantity of HC1 to a concentrated solution of sodium silicate. Hydrofluosilicic acid—H.SiF, —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. H2S04, through water; the disengagement tube being protected from moisture by a layer of mercury. It is used in analysis as a test for K and Na. VI. VANADIUM GROUP. Vanadium—Niobium—Tantalum. The elements of this group resemble those of the N group, but are usually quadrivalent. Vanadium—V—51.3—a brilliant, crystalline metal; sp. gr. =5.5; which forms a series of oxids similar to those of N. No salts of V are known, but salts of vanadyl (VO) are numerous, and are used in the manufacture of anilin black. Niobium—Nb—94—a bright, steel-gray metal; sp. gr. 7.06; which burns in air to Nb206 and in Cl to NbCh; not attacked by acids. Tantalum—Ta—183—closely resembles Nb in its chemical char- acters. VII. MOLYBDENUM GROUP Molybdenum—Tungsten—Osmium. The position of this group is doubtful; and it is probable that the lower oxids 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 oxid Mo03, molybdic anhydrid, combines with lUO to form a number of acids; the ammonium salt of one of which is used as a reagent for H3P04; with which it forms a conjugate acid, phosphomolyb- dic acid, used as a reagent for the alkaloids. Tungsten— Wolfram—W—183.6—a hard, brittle metal; sp. gr. T UNOSTJCN, OS311U 31. 147 17.4. The oxid W03, tungstic anhydrid, is a yellow uowder .orining WI .H-iO several acid hydrates; one of which ineta- tungstic acid, is used as a test for the alkaloids as are also conjugate silicotungstic and phosphotungstic acids. Tissues im- 1 "osmium Wo S?atl->a tun9state are rendered uninflammable. osmium Os—198.0—occurs in combination with Ir in Pt ores- combustible and readily oxidized to OsO«. This oxid known is +aoul\' colorless crystals, soluble in H,<), which give off intensely irritating vapors. It is used as a staining agent by histologists, and also in dentai practice. ok y 148 MANUAL OF CHEMISTRY. CLASS III.—AMPHOTERIC ELEMENTS. Elements whose Oxids Unite with Water, Some to Form Bases, Others to Form Acids. Which Form Oxysalts. I. GOLD GROUP. GOLD. Symbol — Au (AURUM) — Atomic weight = 196.2 — Molecu- lar 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 com- pounds ; in one, AuCl, it is univalent; in the other, AuCL, tri- valent. Its hydrate, auric acid, Au(OH)3, corresponds to the oxid Au202. 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 silver; very malleable and ductile. It is not acted on by H20 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 chlorid. It is oxidized by alkalies in fusion on contact with air. Auric chlorid—Gold trichlorid—AuCl:i—302.7—obtained by dis- solving Au in aqua regia, evaporating at 100° (212° F.), and puri- fying by crystallization from H20. 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 chlorids of tin, deposits a purple double stannate of Sn and Au, called “ purple of Cas- sius.” With alkaline chlorids it forms double chlorids, chlorau- rates (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 HN03 and HC1; soluble in aqua regia, and in yellow NH4HS. (2.) With stannous chlorid and a little chlorin water, a purple-red ppt., insoluble in HC1. (3.) With ferrous sulphate a brown deposit, which assumes the lustre of gold when dried and bur- nished. II. 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 Mn"S04, while in the other CHROMIUM. 149 they are quadrivalent; but when quadrivalent, the atoms do not enter into combination singly, but grouped, two together, to u=|" form a hexavalent unit as in (Fe3)viCl8, (Cr2)vi03. They form several oxids ; of which the oxid M()3 is an anhydrid, cor- responding to which are acids and salts. Most of the other oxids are basic. CHROMIUM. Symbol = Cr—Atomic weight — 52.06—Molecular weight = 104.12 (V)—Bp. gr. = 6.8—Discovered by Vauquelin, 1797—Name from xpuya = color. Occurs iu nature principally as chrome ironstone, a double oxid of Cr and Fe. The element is separated with difficulty by reduction of its oxid by charcoal, or of its chlorid by sodium. It is a hard, crystalline, almost infusible metal. Combines with 0 only at a red heat. It is not attacked by acids, except HC1; is readily attacked by alkalies. Chromic Oxid—Sesquioxid, or green oxid of chromium—Cr203 —152.8—obtained, amorphous, by calcining a mixture of potas- sium dichromate and starch, or, crystallized, by heating neutral potassium chromate to redness in Cl. It is green ; insoluble in H20, acids, and alkalies ; fusible with difficulty, 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 hy- drates 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 decomposing a double borate of chromium and potassium by HnO. It is used in the arts as a substitute for the arsenical greens, and is non-poisonous. Chromic Anhydnd—Acidum chromicum (U. S.)—CrOn—100.4—is formed by decomposing a solution of potassium dichromate by excess of H2SO.», 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 : H2CrCh = chromic acid; H2Cr207 = dichromic acid; and H2Cr3Oio = trichromicacid. Chlorids.—Two clilorids and one oxyclilorid of chromium are known. Chromous chlorid, CrCl2, is a white solid, soluble, with 150 MANUAL OF CHEMISTRY a blue color, in H20. Chromic chlorid, (Cr2)Cl6, forms large, red crystals, insoluble in H20 when pure. Sulphates. — A violet sulphate crystallizes in octahedra, (Cr)2(S04)3 + 15 Aq, and is very soluble in H20. At 100° it is con- verted into a green salt, (Cr)2(S04)3 + 5 Aq, soluble in alcohol; Avliich, at higher temperatures, is converted into the red, insolu- ble, anhydrous salt. Chromic sulphate forms double sulphates, containing 24 Aq,with the alkaline sulphates. (See Alums.) Analytical Characters.—Chromous Salts. — (1.) Potash, a brown ppt. (2.) Ammonium hydrate, greenish-white ppt. (3.) Alkaline sulpliids, black ppt. (4.) Sodium phosphate, blue ppt. Chromic Salts.—(1.) Potash, green ppt.: an excess of precip- itant forms a green solution, from which Cr203 separates on boiling. (2.) Ammonium hydrate, greenish-gray ppt. (3.) Am- monium sulpliydrate, greenish ppt. Chromates.—(1.) H2S in acid solution, brownish color, chang- ing to green. (2.) Ammonium sulpliydrate, greenish ppt. (3.) Barium chlorid, yellowish ppt. (4.) Silver nitrate, brownish-fed ppt., soluble in HN03 or NH4HO. (5.) Lead acetate, yellow ppt., soluble in potash, insoluble in acetic acid. Action on the Economy.—Chromic anhydrid 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. 'Work- men handling the dichromate are liable to a form of chronic poisoning. In acute chromium-poisoning, emetics, and subsequently mag- nesium carbonate in milk, are to be given. Symbol = Mn—Atomic weight = 54—Molecular weight — 108 (?) —Sp. gr. = 7.138-7.206. MANGANESE. Occurs chiefly in pyrolusite, MnOa, hausmanite, Mns04, brau- nite, M112O3, and manganite, Mn203, H20. A hard, grayish, brittle metal; fusible with difficulty ; obtained by reduction of its oxids by C at a white heat. It is not readily oxidized by cold, dry air ; but is superficially oxidized when heated. It decom- poses H20, liberating H ; and dissolves in dilute acids. Oxids.—Manganese forms six oxids or compounds representing them: Manganous oxid, MnO; manganoso-manganic oxid, M113O4; manganic oxid, Mn203 ; permanganic oxid, MnOa, and perman- ganic anhydrid, Mn20-, are known free. Manganic anhydrid, MnOa, has not been isolated. MnO and Mn203 are basic ; M113O4 MANGANESE. 151 and Mn02 are indifferent oxids; and Mn(J3 and Mn207 are anhy- drids, corresponding to the manganates and permanganates. Permanganic Oxid—Manganese dioxid, or black oxid—Man- gani oxidum nigrum (U. S.)—Manganesii ox. nig. (Br.)—-MnO.— 86—exists in nature as pyrolusite, the principal ore of manganese, in steel gray, or brownisli-black, imperfectly crystalline masses. At a red heat it loses 12 per cent, of 0 : 3MnOa = Mii304 + 02 ; and, at a white heat, a further quantity of 0 is given off : 2M113O4 = 6Mn0-t-02. Heated with H2S04, it gives off O, and forms manganous sulphate : 2Mn02+2H2S04 = 2MnS04-t-2H20+ 02. With HC1 it yields manganous clilorid, H20 and Cl : Mii02+ 4HC1 = MnCl2 + 2H20+Cl2. It is not acted on by HN03. Chlorids.—Two clilorids of Mil are known : manganous chlorid, MnCl2, a pink, deliquescent, soluble salt, occurring, mixed with ferric chlorid, in the waste liquid of the preparation of Cl ; and manganic chlorid, Mn2Cl6. Salts of Manganese.—Manganese forms two series of salts : Manganous salts, containing Mn' ; and manganic salts, contain- ing (Mns)Ti; the former are colorless or pink, and soluble in water ; the latter are unstable. Manganous Sulphate—Mangani sulphas (U.S.)—MnSO, + wAq —150+nl8—is formed by the action of H2S04 on Mn02. Be- low 6° (42°.8 P.) it crystallizes with 7 Aq, and is isomorplious 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 H20. insolu- ble in alcohol. With the alkaline sulphates it forms double salts, Avith 6 Aq. Analytical Characters.—Manganous.—(1.) Potash, white ppt., turning brown. (2.) Alkaline carbonates, white ppts. (8.) Am- monium sulpliy(Irate, flesh-colored ppt., soluble in acids, spar- ingly soluble in excess of precipitant. (4.) Potassium ferrocyanid, faintly reddish-white ppt., in neutral solution ; soluble in HC1. (5.) Potassium cyanid, rose-colored ppt., forming brown solution with excess. Manganic.—(1.) H2S, ppt. of sulphur. (2.) Anmfoniuni sulphy- drate, flesh-colored ppt. (3.) Potassium ferrocyanid, greenish ppt. (4.) Potassium ferricyanid, brown ppt. (5.) Potassium cyanid, light browrn ppt. Manganates—are green salts, whose solutions are only stable in presence 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. 152 MANUAL OF CHEMISTRY. IRON. Symbol — Fe (FERRUM)—Atomic weight = 55.9—Molecular weight - 111.8 (?)—Sp. gr. = 7.25-7.9-Fuses at 1600° (2912° F.)— Name from the Saxon, iren. Occurrence.—Free, in small quantity only, in platinum ores and meteorites. As Fe203 in red haematite and specular iron; as hydrates of Fe203 in brown haematite and oolitic iron; as Fe304 in magnetic iron; as FeC03 in spathic iron, clay ironstone and bog 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 reduced 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 chlorid, or of ferric oxid, by H at a temperature approaching redness. Varieties.—Cast iron is a brittle, white or gray, crystalline metal, consisting 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 exist- ing in east iron, 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 puresttforms 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. redactum (Br.)— is Fe, more or less mixed with Fe203 and Fe3G4, obtained by heating Fe203 in II. Properties.—Physical.—Pure iron is silver-white ; quite soft ; crystallizes in cubes or octahedra. Wrought iron is gray, hard, very tenacious, fibrous, quite malleable and ductile, capable of I RON. 153 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 tem- perature. 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 chlorid, while H is liberated. Heated with strong 1I2S04, it gives off S03; with dilute H2S04, H is given off and ferrous sulphate formed. Dilute HN03 dissolves Fe, but the concentrated acid renders it passive, when it is not dissolved by either concentrated or dilute HN03, until the passive condi- tion is destroyed by contact with Pt, Ag or Cu, or by heating to 40° (104° F.). Compounds of Iron.—Oxids.—Three oxids of iron exist free : FeO ; Fe303 ; Fe304. Ferrous Oxid—Protoxul of iron—FeO—71.9—is formed by heating Fe203 in CO or C03. Ferric Oxid—Sesquioxid or peroxid of iron—Colcothar—Jewel- ler's rouge—Venetian red—Fe303—159.8—occurs in nature (see above); and is formed when ferrous sulphate is strongly heated, as in the manufacture of pyrosulphuric acid. It is a reddish, amorphous solid, is a weak base, and is decomposed at a white heat into O and Fe304. Magnetic Oxid—Black oxid—Ferri oxidurn magneticum (Br.) —Fe30i—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 oxids (FeO, Fe303), as acids produce with it mixtures of ferrous and ferric salts. Hydrates.—Ferrous.—When a solution of a ferrous salt is de- composed by an alkaline hydrate, a greenish-white hydrate, FeH202, is deposited ; 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 H6Ob = Ferri peroxidum hydratum (U. S.); Fer. perox. humidum (Br.). It is not formed in the presence of fixed organic acids, or of sugar in sufficient quantity. If pre- served under H20, it is partly oxidized, forming an oxy'hydrate which is incapable of forming ferrous arsenate with As203. If the hydrate, (Fe2)H608, be dried at 100° (212° F.), it loses 2H20, and is converted into (Fe2)02, H303, which is the Ferri peroxidum hydratum (Br.). 154 MANUAL OF CHEMISTRY. If the normal hydrate be dried in vacuo, it is converted into (Fe2)2Hc09, and this, when boiled for some hours with H20, is converted into the colloid or modified hydrate (Fe2)H204 (?), which is brick-red in color, almost insoluble in HN03 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 chlorid 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 coagulated by a trace of H2SC>4, by alkalies, many salts, and by heat; dialyzed iron. Ferric Acid.—H2Fe204.—Neither the free acid nor the oxid, Fe03, are known in the free state ; the ferrates, however, of Na, K, Ba, Sr, and Ca are known. Sulphids.—Ferrous Sulphid—Protosulphid 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 condition, FeS, H20, by treating a solution of a ferrous salt with an alkaline sulphydrate. The dry sulphid is a brownish, brittle, magnetic solid, insoluble in H20, soluble in acids with evolution of H2S. The hydrate is a black powder, 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 Sulphid—Sesquisulphid—Te2S3—207.8—occurs in nature in copper pyrites, and is formed when the disulphid is heated to redness. Ferric Disulphid—FeS2—119.9—occurs in the white and yellow Martial pyrites, used in the manufacture of H2S04. When heated in air, it is decomposed into S02 and magnetic pyrites : 3FeS2 + 202 =Fe3S4 +2S02. Chlorids.—Ferrous Chlorid—Protochlorid—FeCl2—129.9—is pro- duced : (1) by passing dry HC1 over red-hot Fe; (2) by heating ferric chlorid in H ; (3), as a hydrate, FeCl2, 4H20, by dissolving Fe in HC1. The anhydrous compound is a yellow, crystalline, volatile, and very soluble solid. The hydrated is in greenish, oblique rhombic prisms, deliquescent and very soluble in H20 and alcohol. When heated in air it is converted into ferric chlorid, and an oxychlorid. Ferric Chlorid—Sesquichlorid—Per chlorid—Ferri chloridum (U. S.)—Fe2Cl6—324.8—is produced, in the anhydrous form, by heating Fe in Cl. As a hydrate, Fe2Cl6,4H20, or Fe2Clfi,6H20, it is formed : (1) by solution of the anhydrous compound ; (2) by dissolving Fe in aqua regia ; (3) by dissolving ferric hydrate in IKON. 155 HC1; (4) by the action of Cl or of HN03 on solution of ferrous chlorid. It is by the last method that the pharmaceutical prod- uct 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 H20, soluble in alcohol and ether. In solution, it is converted into FeCl2 by reducing agents. The Liq. ferri chloridi (XJ. S.) = Liq. fer. perchloridi (Br.) is an aqueous solution of this com- pound, containing excess of acid. The Tinct. fer. chlor. (XJ. S.) and Tinct. fer. perchl. (Br.) are the solution, diluted with alcohol; and contain ethyl chlorid and ferrous chlorid. Bromids.—Ferrous Bromid — FeBr2 — 215.9—is formed by the action of Br on excess of Fe, in presence of H20. Ferric Bromid—Fe2Br„—591.8—is prepared by the action of excess of Br on Fe. Iodids.—Ferrous Iodid—Ferri iodidum (XJ. S.; Br.)—Fel2—309.9 —is obtained, with 4H20, by the action of 1 upon excess of Fe in the presence of warm HaO. 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 Iodid—Fe2I6—873.8—is formed by the action of excess of I on Fe. Salts of Iron.—Sulphates.—Ferrous Sulphate—Protosulphate— Green vitriol—Copperas—Ferri sulphas (XJ. S.; Br.)—FeSO, + 7 Aq-1 51.9+126—is formed: (1) by oxidation of the sulphid, Fe3S4, formed in the manufacture of H2S04 ; (2) by dissolving Fe in di- lute H2S04. It forms green, efflorescent, oblique rhombic prisms, quite solu- ble in H20, insoluble in alcohol. It loses 6 Aq at 100° (212° F.) (Ferr. sulph. exsiccatus, XI. S.); and the last Aq at about 300° (572 F.). At a red heat it is decomposed into Fe203; S03 and S03. By exposure to air it is gradually converted into a basic ferric sulphate, (Fe2)(S04)3,5Fe203. Ferric Sulphates are quite numerous, and are formed by oxida- tion of ferrous sulphate under different conditions. The normal sulphate, (Fe2)(S04)3, is formed by treating solution of FeS04 with HN03, and evaporating, after addition of one molecule of H2S04 for each two molecules of FeS04. The Liq. fer. tersulphatis (U. S.) contains this salt. It is a yellowish-white, amorphous solid. Of the many basic ferric sulphates, the only one of medical in- terest is Monsel’s salt, 5(Fe2)(S04)3 + 4Fe203, which exists in the Liq. ferri subsulphatis (XJ. S.) and Liq. fer. persulphatis (Br.). Its solution is decolorized, and forms a white deposit with excess of H2S04. 156 MANUAL OF CHEMISTRY. Nitrates.—Ferrous Nitrate—Fe(N03)2—179.9—a greenish, un- stable salt, formed by double decomposition between barium nitrate and ferrous sulphate ; or by the action of HN03 on FeS. Ferric Nitrates.—The normal nitrate—(Fe2)(N03)6—483.8—is ob- tained in solution by dissolving Fe in HN03 of sp. gr. 1.115; or by dissolving ferric hydrate in HN03. It therefore exists in the Liq. ferri nitratis (U. JS.). It crystallizes in rhombic prisms with 18 Aq, or in cubes with 12 Aq. Several basic nitrates are known, all of which are uncrystal- lizable, and by their presence (as when Fe is dissolved in HN03 to saturation) prevent the crystallization of the normal salt. Phosphates.—Triferrous Phosphate—Fe3(P04)2—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 soluble in H20 containing car- bonic or acetic acid. It is probably this phosphate, capable of turning blue, which sometimes occurs in the lungs in phthisis, in blue pus, and in long-buried bones. Ferric Phosphate—(Fe2)(P04)2—301.8—is produced by the action of an alkaline phosphate on ferric chlorid. It is soluble in HC1, HNOs, citric and tartaric acids, insoluble in phosphoric acid and in solution of hydrosodic 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—(Fe2)2(P207)3—745.6—is precipitated by decomposition of a solution of a ferric compound by sodium py- rophosphate ; an excess of the Na salt dissolves the precipitate when warmed, and, on evaporation, leaves scales of a double salt, (Fe2)2(P207)3, Na6(P207)2 + 20 Aq. The ferri pyrophosphas (U. S.) is a mixture of ferric pyrophos- phate, trisodic citrate, and ferric citrate. Acetates.—Ferrous Acetate—Fe(C2H302)a—173.9—is formed by decomposition of ferrous sulphate by calcium acetate, in soluble, silky needles. Ferric Acetates.—The normal salt, (Fe2)(C2H302)«, is obtained by adding slight excess of ferric sulphate to lead acetate, and de- canting after twenty-four hours. It is dark red, uncrystallizable, very soluble in alcohol, and in H20. 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. IKON. 157 Ferrous Carbonate—FeCOa—115.9—occurs asan 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 presence of sugar, hence the addition of that substance in the ferri carbonas saccharatus (U. S.; Br.). It is insoluble in pure HaO, but soluble in H20 containing carbonic acid, probably as ferrous bicarbonate, H2Fe(C03)a, in which form it occurs in chalybeate waters. Ferrous Lactate—Ferri lactas (TJ. S.)—Fe(C;jH503)a+3Aq—233.9+ 54—is formed when iron filings are dissolved in lactic acid. It crystallizes in greenish-yellow needles ; soluble in HaO; insol- uble in alcohol ; permanent in air when dry. Ferrous Oxalate—Ferri oxalas (U. S.) FeC.O,+Aq—143.9+36—is a yellow, crystalline powder ; sparingly soluble in HaO ; formed by dissolving iron filings in solution of oxalic acid. Tartrates — Ferrous Tartrate — FeC4 H ,06+2 Aq—203.9+36. —A white, crystalline powder ; formed by dissolving Fe in hot concen- trated solution of tartaric acid. Ferric Tartrate — Fea(C,H4Os)s+3Aq—555.8+54 — A dirty yel- low, amorphous mass, obtained by dissolving recently precipi- tated ferric hydrate in tartaric acid solution, and evaporating below 59° (122° F.). A number of double tartrates, containing the group (Fe2Oa)' are also known. Such are : Ferrico-ammonic tartrate = ferri et ammonii tartras (U. S.), (C4H408)a(Fea0a), (NH)4+4Aq, and Ferrico-potassic tartrate = ferri et potassii tartras, (U. S.), (C4H408)a(Fea0a)Ka. They are prepared by dissolving recently precipitated ferric hydrate in hot solutions of the hydro-alkaline tartrate. They only react with ferrocyanids and sulphocyanates after addition of a mineral acid. Citrates.—Ferric Citrate—Ferri citras (TJ. S.j—(Fe3)(C,;H,-107)a + 6Aq—489.8+108—is in garnet-colored scales, obtained by dissolv- ing ferric hydrate in solution of citric acid, and evaporating the solution at about 60° (140° F.). It loses 3Aq at 120° (248° F.), and the remainder at 150° (302° F.). If a small quantity of ammo- nium hydrate be added, before the evaporation, the product consists of the modified citrate = ferri et ammonii citras < TJ. S.), which only reacts with potassium ferrocyanid after addition of HC1. The various citrates of iron and alkaloids are not definite compounds. Ferric Ferrocyanid—Prussian blue—(Fea)a(FeC8N8)3+18Aq— 859.3+324—is a dark blue precipitate, formed when potassium ferrocyanid is added to a ferric salt. It is insoluble in HaO, alcohol and dilute acids ; soluble in oxalic acid solution (blue ink). Alkalies turn it brown. 158 MANUAL OF CHEMISTRY. Ferrous Ferricyanid—Turnbull’s blue—Fe3(Fe.»C] ,N12)+aAq— 591.5 +-?il8—is a dark blue substance produced by the action of potassium ferricyanid on ferrous salts. Heated in air it is con- verted into Prussian blue and ferric oxid. Analytical Characters.—Ferrous—Are acid ; colorless when anhydrous ; pale green when hydrated ; oxidized by air to basic ferric compounds. (1.) Potash : greenish-white ppt.; insoluble in excess ; changing to green or brown in air. (2.) Ammonium hy- drate : greenish ppt.; soluble in excess ; not formed in presence of aminoniacal salts. (3.) Ammonium sulphydrate : black ppt.; insoluble in excess ; soluble in acids. (4.) Potassium ferrocyanid (in absence of ferric salts): white ppt.; turning blue in air. (5.) Potassium ferricyanid ; blue ppt.; soluble in KHO ; insolu- ble in HC1. Ferric—Are acid, and yellow or brown. (1.) Potash, or ammo- nium hydrate : voluminous, red-brown ppt.; insoluble in excess. (2.) Hydrogen sulphid : in acid solution ; milky ppt. of sulphur ; ferric reduced to ferrous compound. (3.) Ammonium sulphydrate : black ppt.; insoluble in excess ; soluble in acids. (4.) Potassium ferrocyanid: dark blue ppt.; insoluble in HC1; soluble in KHO. (5.) Potassium sulphocyanate: dark red color; prevented by tartaric or citric acid; discharged by mercuric chlorid. (G.) Tannin: blue-black color. III. ALUMINIUM GROUP. G-lucinium—Aluminium—Scandium—Gallium—Indium. This group is placed in the third class by virtue of the exist- ence of the aluminates, and of the relations between the com- pounds of these elements and some of those of the previous group. They form one series of compounds, corresponding to the ferric, containing the group (M2)vi, but no compounds corre- sponding to the ferrous M" are known. Indeed, certain organic compounds, such as aluminium acetylacetonate, Al(C5H70a)3, seem to contain single, trivalent atoms of the metal. 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 for- bid 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 compounds resemble those of Al, ALUMINIUM. 159 and, in some respects, those of Mg. Its soluble salts are sweet in taste (jXvkvs = sweet). ALUMINIUM. /Symbol = A1—Atomic weight = 27—Molecular weight = 55 (?)— JSp. gr. = 2.56-2.67—Fuses at about 700° (1292° F.)—Name from nlumen=a£um—Discovered by Wohler, 1827. Occurrence.—Exceedingly abundant in the clays as silicate. Preparation.—(1.) By decomposing vapor of aluminium chlorid by Na or K (Wohler). (2.) Aluminium hydrate, mixed with sodium chlorid and charcoal, is heated in Cl, by which a double chlorid of Na and A1 (2NaCl, A13C18) is formed. This is then heated with ATa, 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 sonorous. Chemical.—It is not affected by air or O, except at very high temperatures, and then only superficially. If, however, it con- tain Si, it burns readily in air, forming aluminium silicate. It does not decompose H30 at a red heat ; but in contact with Cu, Pt, or I, it does so at 1003 (212° F.). It combines directly with B, Si, Cl, Br, and I. It is attacked by HC1, gaseous or in solution, with evolution of H, and formation of AlaCl«. It dissolves in alkaline solutions, with formation of aluminates, and liberation of H. It allbys with Cu to form a golden yellow metal (alumin- ium bronze). Aluminium Oxid—Alumina—A1.0:,—102—occurs in nature, nearly pure, as corundum, emery, ruby, sapphire and topaz; and is formed artificially, by calcining the hydrate, or ammonia alum, at a red heat. It is a light, white, odorless, tasteless powder ; fuses with diffi- culty ; and, on cooling, solidifies in very hard crystals. Unless it have been heated to bright redness, it combines with H30, with elevation of temperature. It is almost insoluble in acids and alkalies. H2SCh, diluted with an equal bulk of H20, dissolves it slowly as Fused potash and soda combine with it to form aluminates. It is not reduced by charcoal. Aluminium Hydrate—Aluminium hydroxzd—Aluminii hydras (U. S.)—A1,H,,0 6—156—is formed when a solution of an aluminium salt is decomposed by an alkali, or alkaline carbonate. It con- stitutes a gelatinous mass, which, when dried, leaves an amor- phous, 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 deposits are used as pigments, called lakes. 160 MANUAL OF CHEMISTRY. When freshly precipitated, it is insoluble in H20 ; soluble in acids, and in 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 dialyzing a solution of A12H608 in A12C16, or by heating a dilute solution of aluminium acetate for 24 hours. Aluminates are for the most part crystalline, soluble com- pounds, obtained by the action of metallic oxids or hydrates upon alumina. Potassium aluminate, K2Al204-l-3Aq, is formed by dissolving recently precipitated 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, KoAhCb. Sodium Aluminate.—The aluminate Na2Al204 is not known. That having the composition NaeAhOs 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 H20, and is decomposed by carbonic acid, with precipitation of aluminium hydrate. Aluminium Chlorid—Al2Clr>—267—is prepared by passing Cl over a mixture of A1203 and C, heated to redness ; or by heating clay in a mixture of gaseous HC1 and vapor of CS2. * It crystallizes in colorless, hexagonal prisms ; fusible ; volatile ; deliquescent; 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. Aluminium Sulphate—Aluminii sulphas (U.S.)—(Al2)(SO,)3 -+- 18 Aq—342 -t- 324—is obtained by dissolving A12H608 in H2S04 ; or (industrially) by heating clay with H2S04. It crystallizes, with difficulty, in thin, flexible plates; soluble in H20 ; very sparingly soluble in alcohol. Heated, it fuses in its Aq, which it gradually loses up to 200° (392 F.), when a white, amorphous powder, (A12)(S04)3, 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 crystal- lized, they have the general formula: (M2)vi(S04)3.R 2S04 + 24 Aq, in which (M) may be (Fe2), (Mn2), (Cr2), (Al2), or (Gra2); and R2 may be K2, Na2, Rb2, Cs2, Tl2, or (NH4)2. They are isomor- plious with each other. Alumen (U. S.)—A12(S04)3,K2S04 + 24 Aq—516 + 432—is manu- factured from “alum shale,” and is formed when solutions of the sulphates of A1 and K are mixed in suitable proportion. ALUMINIUM. 161 It crystallizes in large, transparent, regular octahedra; has a sweetish, astringent taste, and is readily soluble in HaO. Heated, it fuses in its Aq at 92° (197=.6 F.); and gradually loses 45.5 per cent, of its weight of HaO, as the temperature rises to near red- ness. The product, known as burnt alum = alumen exsiccatum (U. S.), is (Al)a(S04)3, KaSCh, and is slowly, but completely solu- ble in 20-30 pts. HaO. At a bright red heat, SOa and O are given off, and AlaOa and potassium sulphate remain ; at a higher tem- perature, potassium aluminate is formed. Its solutions are acid in reaction; dissolve Zn and Fe with evolution of H ; and deposit AlaHaOe when treated with ammonium hydrate. Alumen (Br.)—Ala(S04)3,(NH4)aS04 -I- 24 Aq—474 + 432—is the compound*now usually met with as alum, both in this country and in England. It differs from potash alum in being more solu- ble in HaO, 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 incom- pletely soluble in HaO. More stongly heated, it leaves alumina. Silicates—are very abundant in the different varieties of clay, feldspar, 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 pow- der. 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 fash- ioned articles are subjected to a first baking. The porous, baked clay is then coated with a glaze, usually composed of oxid 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 chlorid into the fire ; the salt is volatilized, and, on contact with the hot aluminium sili- cate, deposits a coating of the fusible sodium silicate, which hardens on cooling. Analytical Characters.—(1.) Potash, or soda; white ppt. ; solu- ble in excess. (2.) Ammonium hydrate; white ppt. ; almost in- soluble in excess, especially in presence of ammoniacal salts. (3.) Sodium phosphate; white ppt.; readily soluble in KHO and NaHO, but not in NH ,HO ; soluble in mineral acids, but not in acetic acid. (4.) Blowpipe—on charcoal does not fuse, and moist- ened with cobalt nitrate solution turns dark sky-blue. 162 MANUAL OF CIIEMISTI1Y. Symbol — Sc—Atomic weight — 44.9—Discovered by Nilson (1879) —Name from Scandia. Occurs in minute traces in gadolinite and euxenite. It forms an oxid, Sc203; a light, white, infusible powder; sp. gr. 3.8; re- sembling alumina. SCANDIUM. GALLIUM. Symbol = Ga—Atomic weight — 68.8—Sp. gr. — 5.9—Fuses at 36° (86° F.)—Name from Gallia—Discovered by Lecoq de lioisbaudran (1876). Occurs in very small quantity in certain zinc blendes. It is a hard, white metal; soluble in hot HN03, in HC1, and in KHO solution. In chemical characters it closely resembles A1 ; forms an oxid, Ga203, and a series of alums. The discovery of Sc and Ga affords most flattering verifications of predictions based upon purely theoretical considerations. It has been observed that there exist numerical relations be- tween 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 I. Group II. Group III. Group IV. Group V. Group VI. Group V. Group. VI. 1 rh4 ro2 RHS R2Q5 rh2 R03 RH R20, (R2H) (R04) r2o H=1 Li=? RO R2O3 2 Be=9 B=ll C=12 N=14 0=16 F=19 3 Na=23 K=39 Mg=24 Ca=40 Al=27 Sc=44 Si=28 Ti=48 P=31 V=51 S=32 Cr=52 Cl=35 Mn=55 Cu=63 Fe=56 Co=59 Ni=59 4 5 (Cu=63) Rb=85 Zn=65 Sr=87 Ga=69 Yt=88 Ge=72 Zr=90 As=75 Nb=94 Se=78 Mo=96 Br=80 ?=100 Ru=104 Rh=:104 Pd =106 Ag=108 6 7 (Ag=108) Cs=i33 jCd=112 |Ba=137 In=113 La=139 Sn=118 Ce=142 Sb=120 Di=145 Te=125 Sm=i50 1=127 Da=154 8 9 E=166 Yb=173 Os =195 Ir=193 Pt=195 Au = 197 10 Ta=182 W=184 ?=190 11 (Au=196) Hg=200 Tl=204 Pb=207 Th=231 Bi=208 12 U=238 INDIUM, URANIUM, LEAD. 163 The atomic weights and chemical characters, which were an- nounced by Mendelejeff in 1870 as those of the undiscovered ele- ments which would occupy the positions 4 and 5 in group 111. have been since found to be those of Sc and Ga. Still later, the vacant positions 10, III., 5, IV., 8, VI., and 8, V., have been filled by the discovery of Yb, Ge, Sm, and Da. INDIUM Symbol = In—Atomic weight= 113.4—gr.= 7.42—Fuses at 176° (348°.8 F.)—Discovered by Reich and Richter in 1863. A soft, silver-white, ductile metal, which occurs in small quan- tity in certain zinc blendes. It is characterized spectroscopically by two principal lines—A = 4511 and 4101. IV. URANIUM GROUP. URANIUM Symbol = Ur—Atomic weight — 238.5—Sp. gr.= 18.4—Discovered by Klaproth (1789). This element is usually classed with Fe and Cr, or with Ni and Co. It does not, however, form compounds resembling the ferric ; it forms a series of well-defined uranates, and a series of compounds of the radical uranyl (UO)'. Standard solutions of its acetate or nitrate are used for the quantitative determina- tion of H3PO4. V. LEAD GROUP. LEAD. Symbol = Pb (PLUMBUM)—Atomic weight = 206.9—Molecular weight = 413.8 (?)—Sp. gr.— 11.445—Fuses at 325° (617° F.)—Name from Iced = heavy (Saxon). Uead is usually classed with Cd, Bi, or Cu and Hg. It differs, however, 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 compounds 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 potassium plumbate. 164 MANUAL OF CHEMISTRY. Occurrence.—Its most abundant ore is galena, PbS. It also occurs in white lead ore, PbC03, in anglesite, PbS04, and in horn lead PbCl2. Preparation.—Galena is first roasted with a little lime. The mixture of PbO, PbS, and PbS04, so obtained, is strongly heated in a reverberatory furnace, when S02 is driven off. The impure work lead, so formed, is purified by fusion in air, and removal of the film of oxids 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 subsequent oxidation of the remaining Pb. Properties.—Physical.—It is a bluish-white metal ; brilliant upon freshly cut surfaces ; very soft and pliable ; not very malle- able or ductile; crystallizes in octahedra; a poor conductor of electricity ; a better conductor 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 completely 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 oxi- dized, and the oxid dissolved in the H20, leaving a metallic sur- face 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 chlorids. On the other hand, carbonates, sulphates, and phosphates, by their tendency to form insoluble coatings, diminish the corroding action of H20. Carbonic acid in small quantity, especially in presence of carbonates, tends to preserve Pb from solution, while H20 highly charged with it (soda water) dissolves the metal readily. Lead is dissolved, as a nitrate, by HNOa. H2S04 when cold and moderately concentrated, 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 C02, converts it into white lead. Oxids.—Lead Monoxid—ProtoxicL—Massicot—Litharge — Plum- bi oxidum (U. S.; Br.)—PbO—222.9—is prepared by heating Pb, or its carbonate, 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 powder; or crystallizes, from its solution in soda or potash, in white, rhombic dodecaliedra, or in rose-colored cubes. It fuses near a red heat, and volatilizes at a white heat ; sp. gr. 9.277-9.5. It is sparingly soluble in H20, forming an alka- line solution. Heated in air to 300° (572° F.) it is oxidized to minium. It is LEAD. 165 readily reduced by H or C. With Cl it forms PbCla and O. It is a strong base ; decomposes alkaline salts, w ith liberation of the alkali. It dissolves in HNOs, 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 w’hich, lead oleate, is the emplastrum plumbi, U. S.; Br. It also combines with the alkalies and earths to form plumbites. Calcium plumbile, CaPba03, is a crystalline salt, formed by heat- ing PbO with milk of lime, and used in solution as a hair-dye. Plumboso-plumbic Oxid—Red oxid—Minium—Red lead—Pb3 04—(584.7—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, PbO. 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. HNOs changes its color to browrn, dissolving PbO and leaving PbOa. It is decomposed by HC1, with formation of PbCla, HaO and Cl. Lead Dioxid—Peroxid, or puce oxid, or brown oxid, or binoxid of lead—Plumbic anhydrid—PbO>—238.9—is prepared, either by dissolving the PbO out of red lead by dilute HN03, or by passing a current of Cl through HaO, holding lead carbonate in suspen- sion. It is a dark, reddish-brown, amorphous powder; sp. gr. 8.903- 9.190; insoluble in HaO. Heated, it loses half its O, and is con- verted into PbO. It is a valuable oxidant. It absorbs SOa to form PbS04. It combines wdth alkalies to form plumbates, M3Pb03. Plumbic Acid—PbO,Ha—256.9—forms crystalline plates, at the -+- electrode, when alkaline solutions of the Pb salts are decom- posed by a weak current. Lead Sulphid—Galena—PbS—338.9—exists in nature. It is also formed by direct union of Pb and S ; by heating PbO with 8, or vapor of CSa; or by decomposing a solution of a Pb salt by HaS or an alkaline sulphid. The native sulphid is a 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 subsulphate. Heated in air it is converted into PbS04, PbO and SOa. Heated in H it is reduced. Hot HN03 oxidizes it to PbS04. Hot HC1 converts it into PbCla. Boiling HaS04 converts it into PbS04 and SOa. Lead Chlorid—PbCla—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 decomoosition between a lead-salt and a chlorid. 166 MANUAL OF CHEMISTRY. It crystallizes in plates, or hexagonal needles ; sparingly solu- ble in cold HsO, less soluble in H20 containing HC1; more solu- ble in hot H20, and in concentrated HC1. Several oxychlorids are known. Cassel, Paris, Verona, or Turner’s yellow is PbCl2, 7PbO. Lead Iodid—Plumbi iodidum (U. S.; Br.)—Pbl2—460.9—is de- posited, as a bright yellow powder, when a solution of potassium iodid is added to a solution of a Pb salt. Fused in air, it is con- verted into an oxyiodid. Light and moisture decompose it, with liberation of I. It is almost insoluble in H20, soluble in solutions of ammonium chlorid, sodium hyposulphite, alkaline iodids, and potash. Nitrates. — Lead Nitrate — Plumbi nitras — (TJ. S. ; Br.)— Pb(N03)2—330.9—is formed by solution of Pb, or of its oxids, in excess of HNO3. It forms anhydrous crystals; soluble in H20. Heated, it is decomposed into PbO, O and N02. Besides the neutral nitrate, basic lead nitrates are known, which seem to indicate the existence of nitrogen acids similar to those of phosphorus ; Pb3(N04)2—orthonitrate; and Pb2N207— pyronitrate. Lead Sulphate—PbS04—302.9—is formed by the action of hot, concentrated H2S04 on Pb ; or by double decomposition between a sulphate and a Pb salt in solution. It is a white powder, almost insoluble in H20, soluble in concentrated H2S04, from which it is deposited by dilution. Lead Chromate—Chrome yellow—PbCr04—323.3—is formed by decomposing Pb(N03)2 with potassium chromate. It is a yellow, amorphous powder, insoluble in H20, soluble in alkalies. Acetates.—Neutral Lead Acetate—Salt of Saturn—Sugar of Lead—Plumbi acetas (U.S.; Br.)—Pb(C.H02)2 + 3Aq—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 metallic 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 C02 ; Pb, and acetone. Its aqueous solution dissolves PbO, with formation of basic acetates. Sexbasic Lead Acetate—Pb(C2H:i02)0H, 2PbO—728.7—is the main constituent of Goulard’s extract = Liq. plumbi subacetatis (XT. S. ; Br.), and is formed by boiling a solution of the neutral acetate with PbO in fine powder. The solution becomes milky on addition of ordinary H20, from formation of the sulphate and carbonate. LEAD. 1G7 Lead Carbonate—PbC03—2G0.9—occurs in nature ascerusite; and is formed, as a white, insoluble powder, when a solution of a Pb compound is decomposed by an alkaline carbonate, or by passing COa through a solution containing Pb. The plumbi carbonas (TJ. S. ; Br.), or white lead or ceruse, is a basic carbonate (PbC03)3, 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 presence of C02; soluble in acids with effervescence ; and decomposed by heat into C02 and PbO. Analytical Characters.—(1.) Hydrogen sulphid, in acid solu- tion : a black ppt. ; insoluble in alkaline sulphids, and in cold, dilute acids. (2.) Ammonium sulphydrate : black ppt. ; insolu- ble in excess. (3.) Hydrochloric acid : white ppt. ; in not too dilute solution ; soluble in boiling HaO. (4.) Ammonium hy- drate : white ppt. ; insoluble in excess. (5.) Potash: white ppt. ; soluble in excess, especially when heated. (6.) Sulphuric acid: white ppt. ; insoluble in w-eak acids, soluble in solution of am- monium tartrate. (7.) Potassium iodid : yellow ppt. ; sparingly soluble in boiling H20 ; soluble in large excess. (8.) Potassium chromate : yellow ppt. ; soluble in KHO solution. (9.) Iron or zinc separate the element from solution of its salts. Action on the Economy.—All the soluble compounds of Pb, and those which, although not soluble, are readily convertible into soluble compounds by H20, air, or the digestive fluids, are ac- tively 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 quantities of Pb, either by the skin, lungs, or stomach. The acute form presents 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 convertible into compounds capable of absorption. The principal sources of poisoning by metallic Pb are : the contamination of drinking water which has been in contact with the metal (see p. 72); 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 handling of the metal and its alloys. 168 MANUAL OF CHEMISTRY. 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 oxids, in the manufactures of glass, pottery, sealing-wax, and litharge, and by the use of lead-glazed pottery ; by other compounds, by the inhalation of the dust of cloth factories, and by the use of lead hair-dyes. Acute lead-poisoning is of by no means as common occurrence as the chronic form, and usually terminates in recovery. It is caused by the ingestion of a single large dose of the acetate, sub- acetate, carbonate, or of red lead. In such cases the administra- tion of magnesium sulphate is indicated; it enters into double decomposition with the Pb salt to form the insoluble PbS04. Lead, once absorbed, is eliminated very slowly, it becoming fixed by combination with the albuminoids, a form of combina- tion which is rendered soluble by potassium iodid. The channels of elimination are by the perspiration, urine and bile. In the analysis for mineral poisons (see p. 136), the major part of the Pb is precipitated as PbS in the treatment by H2S. The PbS remains upon the filter after extraction with ammonium sulphydrate. It is treated with warm HC1, which decolorizes it by transforming the sulpliid into chlorid. The PbCl2 thus formed is dissolved in hot H20, 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 econ- omy, and the slowness of its elimination, are such as to render the greatest caution necessary in drawing conclusions from the detection of Pb in the body after death. VI. BISMUTH GROUP. Symbol — Bi—Atomic weight = 207.5—Molecular weight = 420 (T)—Sp. gr. = 9.677-9.985—Fuses at 268° (514°.4 F.). BISMUTH. This element is usually classed with Sb ; by sdme writers among the metals, by others in the phosphorous 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 BISMUTH. 169 compounds except one, which is very unstable, in which it is quinquivalent; (3) the hydrates of the N group are strongly acid, and their corresponding salts are stable and well deiined ; 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 Bia03 and BiaSa. 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 oxid. In Ha0, con- taining COa, it forms a crystalline subcarbonate. It combines directly with Cl, Br, and I. It dissolves in hot HaS04 as sulphate, and in HX03 as nitrate. It is usually contaminated with As, from which it is best puri- fied by heating to redness a mixture of powdered bismuth, po- tassium 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 oxid. Oxids.—Four oxids are known: Bi2Oa; Bi303 ; Bi204; and BiaOs. Bismuth Trioxid—Bismuthous oxid—Protoxid—Bia03—468—is 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, HN03 and H3S04 and in fused potash. Hydrates.—Bismuth forms at least four hydrates. Bismuthous Hydrate—BiH,03—261—is formed, as a white pre- cipitate, when potash or ammonium hydrate is added to a cold solution of a Bi salt. When dried, it loses HaO, and is converted into bismuthyl hydrate (BiO)HO. Bismuthic Acid—(BiOa)HO—259—is deposited, as a red powder, when Cl is passed through a boiling solution of potash, holding bismuthous hydrate in suspension. When heated it is converted into the pentoxid, Bia05. Pyrobismuthic Acid—H,BiaOT—536—is a dark brown powder, precipitated from solution of bismuth nitrate by potassium cyanid. Bismuth. Trichlorid—Bis mu thous chlorid — BiCl3 — 316.5 — is formed by heating Bi in Cl; by distilling a mixture of Bi and mercuric chlorid ; 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 bis- muthyl chlorid (BiO)Cl, or pearl white. 170 MANUAL OF CHEMISTRY. Bismuth Nitrate—Bi(N03)3+5 Aq—396+90—obtained by dis- solving Bi in HNOs. It crystallizes in large, colorless prisms ; at 150° (302° F.), or by contact with H20, it is converted into bis- rnuthyl nitrate ; at 260° (500° F.) into Bi203. Bismuthyl Nitrate—Trisnitrate or subnitrate of bismuth— Flake white—Bismuth! subnitras (U. S. ; Br.)—(Bi0)N03H20— 306—is formed by decomposing a solution of Bi(N03)3 with a large quantity of H20. It is a white, heavy, faintly acid powder ; sol- uble to a slight extent in H20 when freshly precipitated, the solu- tion depositing it again on standing. It is decomposed by pure H20, but not by H20 containing ammonium nitrate. It usually contains 1 Aq, which it loses at 100° (212° F.). Bismuth subnitrate, as well as the subcarbonate, is liable to contamination with arsenic, which accompanies bismuth in its ores. The method for separating this dangerous impurity, directed by the British Pharmacopoeia, is more perfect than that usually followed in this country. The metal is first purified by fusion with potassium nitrate, which dissolves any arsenic present in the form of sodium arsenite, and the purified metal is then converted into nitrate by solution in HN03, and this in turn into subnitrate by decomposition with a large volume of H20. The maximum amount of arsenic which has been found in commercial bismuth subnitrate is one-tenth of one per cent. To detect the presence of arsenic, the subnitrate (or subcarbon- ate) is boiled for half an hour with an equal weight of pure sodium carbonate, dissolved in ten times its weight of H20. The solution is filtered ; the filtrate evaporated to dryness ; the resi- due strongly heated ; and, after cooling, cautiously decomposed with strong H2S04. The mass is then gradually heated, during stirring, until dense white fumes are given off. The cooled resi- due is finally treated with water and the liquid introduced into a Marsh apparatus. (See page 133.) Bismuthyl Subcarbonate—Bismuth! subcarbonas (TJ. S.)—Bis- muthi carbonas (Br.)—(Bi0)2C0;,H20—530—is a white or yellowish, amorphous powder, formed when a solution of an alkaline car- bonate is added to a solution of Bi(N03)3. It is odorless and taste- less, and insoluble in H20 and in alcohol. When heated to 100° (212° F.), it loses H20, and is converted into (Bi0)2C03. At a higher temperature it is further decom- posed into Bi203 and C02. Analytical Characters.—(1.) Water : white ppt., even in pres- ence of tartaric acid, but not of HN03, HC1, or H2S04. (2.) Hydrogen sulpliid : black ppt. ; insoluble in dilute acids and in alkaline sulpliids. (3.) Ammonium sulphydrate : black ppt.; in- soluble in excess. (4.) Potash, soda, or ammonia : white ppt., in- TITANIUM, ZIRCONIUM. 171 soluble in excess, and in tartaric acid; turns yellow when the liquid is boiled. (5.) Potassium ferrocyanid : yellowish ppt. ; in- soluble in HC1. (6.) Potassium ferricyanid : yellowish ppt.; solu- ble in HC1. (7.) Infusion of galls : orange ppt. (8.) Potassium iodid : 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 are probably poisonous, if taken in sufficient quantity, the ill effects ascribed to them are in most, if not all cases, refer- able to contamination with arsenic. Symptoms of arsenical poisoning have been frequently observed when the subnitrate has been taken internally, and also when it has been used as a cosmetic. When preparations of bismuth are administered, the alvine discharges contain bismuth sulphid, as a dark brown powder. VII. TIN GROUP. Titanium. Zirconium. Tin. Ti and Sn are bivalent in one series of compounds, SnCl2, and quadrivalent in another, SnCh. Zr, so far as known, is always quadrivalent. Each of these elements forms an acid (or salts corresponding to one) of the composition HaMOs, and a series of oxysaltsof the composition Miv(N03)<. TITANIUM. Symbol = Ti—Atomic weight = 48—Sp. gr. = 5.8. Occurs in clays and iron ores, and as TiOa in several minerals. Titanic anhydrid, TiOa, is a white, insoluble, 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'NHs is passed over red-hot TiOa, it is decomposed with formation of the violet nitrid, TiNa. Another compound of Ti and N forms hard, cop- per-colored, cubical crystals. ZIRCONIUM. Symbol = Zr—Atomic weight = 89.G—Sp. gr. = 4.15. Occurs in zircon and hyacinth. Its oxid, zirconia, Zr02, is a white powder, insoluble in KHO. Being infusible, and not altered by exposure to air, it is used in pencils to replace lime in the calcium light. 172 MANUAL OF CHEMISTRY. TIN. Symbol = Sn (STANNUM)—Atomic weight = 117.7—Molecular weight = 235.4 (?)—8p. gr. = 7.285-7.293—Fuses at 228° (442°.4 F.). Occurrence.—As tinstone (Sn02) or cassiterite, 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 HC1; filtering ; evaporating ; dissolving the residue in H20 ; decomposing with ammonium carbonate ; and reducing the oxid with charcoal. Properties.—A soft, malleable, bluish-white metal ; but slightly tenacious; 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 H20, more rapidly in the presence of sodium chlorid. Its presence with Pb accelerates the action of H20 upon the latter. It dissolves in HC1 as SnCl2. In presence of a small quantity of H20, HN03 converts it into metastannic acid. Alka- line 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 con- sists 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. Oxids.—Stannous Oxid—Protoxid—SnO—133.7—obtained by heating the hydrate or oxalate without contact of air. It is a white, amorphous powder, soluble in acids, and in hot concen- trated solution of potash. It absorbs O readily. Stannic Oxid.—Binoxid of tin—Sn02—149.7—occurs native as tinstone or cassiterite, and is formed when Sn or SnO is heated in air. It is used as a polishing material, under the name of putty powder. Hydrates.—Stannous Hydrate—SnH202—151.7—is a white pre- cipitate, formed by alkaline hydrates and carbonates in solu- tions of SnCl2. Stannic Acid.—H2SnO:)—167.7—is formed by the action of alka- line hydrates on solutions of SnCh. It dissolves in solutions of the alkaline hydrates, forming stannates. Metastannic Acid.—H2Snr,On—766.5—is a white, insoluble pow- der, formed by acting on Sn with HNOs. Chlorids.—Stannous Chlorid—Protochlorid—Tin crystals—Sn Cl2 + 2 Aq—188.7 + 36—is obtained by dissolving Sn in HC1. It 173 PLATINUM. cry stallizes in colorless prisms; soluble in a small quantity of Ha0 ; decomposed by a large quantity, unless in the presence of free HC1, with formation of an oxychlorid. Loses its Aq at 100’ (212° F.). In air it is transformed into stannic chlorid and oxy- chlorid. Oxidizing and chlorinating agents convert it into SnCL. It is a strong reducing agent. Stannic Chlorid—Bichlorid—Liquid of Libavius—SnCL—259.7 —is formed by acting on Sn or SnCL with Cl, or by heating Sn in aqua regia. It is a fuming yellowish liquid ; sp. gr. 2.28 ; boils at 120° (248° F.). Analytical Characters.—Stannous.—(1.) Potash or soda : white ppt. ; soluble in excess; the solution deposits Sn when boiled. (2.) Ammonium hy'drate : white ppt. ; insoluble in excess ; turns olive-brown when the liquid is boiled. (3.) Hydrogen sulphid : dark browrn ppt. ; soluble in KHO, alkaline sulphids, and hot H20. (4.) Mercuric chlorid : white ppt. ; turning gray and black. (5.) Auric chlorid : purple or brown ppt., in presence of small quantity of HNCb. (6.) Zinc : deposit of Sn. Stannic.—(1.) Potash or ammonia : white ppt.; soluble in excess. (2.) Hydrogen sulphid: yellow ppt.; soluble in alkalies, alkaline sulphids, and hot HCL. (3.) Sodium hyposulphite : yellow ppt. when heated. VIII. PLATINUM GROUP. Palladium. Platinum. IX. RHODIUM GROUP. Rhodium. Ruthenium. Iridium. The elements of these two groups, together with osmium, are usually classed as “metalsof the platinum ores.” They all form hydrates (or salts representing them) having acid properties. Osmium has been removed, because the relations existing be- tween its compounds, and those of molybdenum and tungsten, are much closer than those which they exhibit 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: Chlorids. PdCL PtCl, PdCL PtCl4 RhCL RuCb ? RuCL IrCL RhaCls RujCls Ir2Cl# 174 MANUAL OF CHEMISTRY. Oxids. PdO PtO PdoV.....'.... PtOa RhO RuO IrO RI12O3 RU2O3 Ir203 Rh02 RuOa Ir02 RhOs Ru03 IrOs Ru04 PLATINUM. Symbol = Pt—Atomic weight = 194.4—Molecular weight = 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 heating the double chlorid of Pt and NH4. Platinum black is a black powder, formed by dissolving PtCl2 in solution of potash, and heating with alcohol. Both platinum black and platinum sponge are capable of condensing 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 oxids. It is attacked by mixtures liberating Cl, and by contact with heated phos- phates, silicates, hydrates, nitrates, or carbonates of the alka- line metals. Platinic chlorid—Tetrachlorid or perchlorid of platinum— PtCl4—336.4—is obtained by dissolving Pt in aqua regia, and evaporating. It crystallizes in very soluble, deliquescent, yel- low needles. Its solution is used as a test for compounds of NH, and K. PALLADIUM. Symbol = Pd—Atomic weight — 105.7—Molecular weight — 211.4 (?)—Sp. gr. =11.5. A white metal, resembling Pt in appearance; but usually exhib- iting a reddish reflection. It is harder, much lighter, and more readily fusible than Pt. It dissolves in HNOs, as Pd(N03)2. It possesses the property of occluding gases, notably hydrogen, in a much more marked degree than any other metal. One volume of palladium condenses (?40 volumes of hydrogen at 100° (212° F.). RHODIUM, RUTHENIUM, IRIDIUM. 175 RHODIUM. Symbol = Rh — Atomic weight = 104.1 — Molecular weight = 208.2 (?)—Sp. gr. = 11.4. A hard, malleable, white metal, insoluble in aqua regia. Its compounds are mostly red, whence its name, from p66ov a rose. RUTHENIUM A hard, brittle, very difficultly fusible metal, not dissolved by aqua regia, occurring in small quantity in platinum ores. Symbol = Ru—Atomic weight = 104.2—Sp. gr. = 11.4 IRIDIUM. A hard, brittle metal which occurs in nature in platinum ores, and alloyed with osmium. It is not attacked by aqua regia. It is used to make an alloy with platinum, which is less fusible, more rigid, harder, denser, and less readily attacked chemically than pure platinum. Symbol = Ir—Atomic weight = 192.7—Sp. gr. = 22.3 176 MANUAL OF CHEMISTRY. CLASS IV — BASYLOUS ELEMENTS. Elements whose Oxids Unite with Water to form Bases ; never to form Acids. Which form Oxysalts. I. SODIUM GROUP. Alkali Metals. Lithium—Sodium—Potassium—Rubidium—Cesium—Silver. Each of the elements of this group forms a single chlorid, M CI, and one or more oxids, the most stable of which has the compo- sition M'20 ; they are, therefore, univalent. Their hydrates, H HO, are more or less alkaline and have markedly basic charac- ters. Silver resembles the other members of the group in chemi- cal 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 kideiog = 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 ; decom- poses H20 at ordinary temperatures, without igniting. Lithium Oxid—Li20—30—is a white solid, formed by burning Li in dry O. It dissolves slowly in HaO to form lithium hydrate— LiHO. Lithium Chlorid—LiCl—43.5—crystallizes in deliquescent, reg- ular octaliedra ; very soluble in II20 and in alcohol. Lithium Bromid—Lithii bromidum (U. S.)—LiBr—87—is formed by decomposing lithium sulphate with potassium bromid ; or by saturating a solution of HBr with lithium carbonate. It crystal- lizes in very deliquescent, soluble needles. Lithium Carbonate—Lithii carbonas (U. S.; Br.)—Li .CO ,—74—is a white, sparingly soluble, alkaline, amorphous powder. With uric acid it forms lithium urate (g. •«.). 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 neu- tral or alkaline solution; soluble in acids and in solutions of ammoniacal salts. (3.) It colors the Bunsen flame red ; and ex- hibits a spectrum of two lines—A = 6705 and 6102 (Fig. 16, No. 4). SODIUM. 177 SODIUM. Symbol = Na (NATRIUM) — Atomic weight = 23—Molecular weight = 46 (?)—Sp. gr. =0.972—Fuses at 95°.6 (204°.1 F.)—Boils at 742° (1368° F.)—Discovered by Davy, 1807. Occurrence.—As chlorid, very abundantly and widely distrib- uted ; 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 ; vola- tile at a white heat, forming a colorless vapor, which burns in air with a yellow flame. 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 HaO, sometimes explosively. Burns with a yellow flame. Combines directly with Cl, Br, I, S, P, As, Pb, and Sn. Oxids.—Two oxids are known : Sodium monoxid—NaaO—a grayish-white mass ; formed when Na is burnt in dry air, or by the action of Na on NaHO. Sodium dioxid—NaaOa—a white solid, formed when Na is heated in dry air to 200° (392° F.). Sodium hydrate—Sodium hydroxid—Caustic Soda—Soda (U. S.) —Soda caustica (Br.)—NaHO—40—is formed : (1) when HaO is decomposed by Na ; (2) by decomposing sodic carbonate by cal- cium hydrate : NaaC03 -I- CaHaOa = C03Ca + 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 consider- able quantities of As. It is an opaque, white, fibrous, brittle solid ; fusible below red- ness ; sp. gr. 2.00 ; very soluble in HaO, forming strongly alkaline and caustic solutions (soda lye and liq. sodse). When exposed to air, solid or in solution, it absorbs HaO and C03, and is converted into carbonate. Its solutions attack glass. Sodium chlorid—Common salt—Sea salt—Table salt—Sodii chloridum (TJ. S., Br.)—NaCl—58.5—occurs very abundantly in nature, deposited in the solid form as rock 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 infi- nite variety of chemical reactions. It is obtained from rock salt, or from the waters of the sea or of saline springs ; and is the 178 MANUAL OF CHEMISTRY. source from which all the JSTa compounds are usually obtained, directly or indirectly. It crystallizes in anhydrous, white cubes, or octaliedra ; sp. gr. 2.078 ; fuses at a red heat, and crystallizes on cooling ; sensibly volatile at a white heat; quite soluble in HaO, the solubility varying but slightly with the variations of temperature. Dilute solutions yield almost pure ice on freezing. It is precipitated from concentrated solutions by HC1. It is insoluble in absolute alcohol; sparingly soluble in dilute spirit. It is decomposed by H2SO4 with formation of HC1 and sodium sulphate : 2NaCl 4- H2S04 = 2HC1 + Na2S04. Physiological.—Sodium chlorid exists in every animal tissue and fluid, and is present in the latter, especially the blood, in tolerably constant proportion. It is introduced with the food, either as a constituent of the alimentary substances, or as a con- diment. In the body it serves to aid the phenomena of osmosis, and to maintain the solution of the albuminoids. 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 elimi- nation, 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), cor- responding 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 elimi- nation 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 dimin- ished 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 chlorids in urine.—The process is based upon the formation of the insoluble silver chlorid, and upon the formation of the brown silver chromate in neutral liquids, in the absence of soluble chlorids. The solutions required are : (1) A solution of silver nitrate of known strength, made by dissolving 29.075 grams of pure, fused silver nitrate (see p. 193) 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 chlorid) are added ; the whole is evaporated to dryness over the Avater- bath, and the residue heated gradually until a colorless, fused SODIUM. 179 mass remains. This, on cooling, is dissolved in H20, the solution placed in a small beaker, treated with pure, dilute HXO3 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 perma- nent. Each c.c. of the silver solution used represents 10 milli- grams NaCl (or 6.0G5 milligrams Cl) in the amount of urine used. Example.—5 c.c. urine used ; G c.c. silver solution added ; 1,200 c.c. urine passed in 24 hours : 1,200—14.4 grams NaCI in 24 hours. If the urine contain iodids or bromids, they must be removed, by acidulating the solution or the residue of incineration with H2S04, removing the iodin or bromin by shaking with carbon disulphid, neutralizing the aqueous solution with calcium car- bonate and proceeding as above. Sodium Bromid—Sodii bromidum (TJ. S.)—NaBr—103—is formed by dissolving Br in solution of NaHO to saturation ; evaporating ; calcining at dull redness ; redissolving ; filtering; and crystal- lizing. It crystallizes in anhydrous cubes ; quite soluble in H20, soluble in alcohol. Sodium Iodid—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 soluble in H20 ; soluble in alcohol. Sodium Nitrate—Cubic or Chili saltpetre—Sodii nitras (TJ. S.) —Sodse nitras (Br.)—NaNOa—85—occurs in natural deposits in Chili and Peru. It crystallizes in anhydrous, deliquescent rhom- bohedra ; cooling and somewhat bitter in taste ; fuses at 3103(590° F.); very soluble in H20. Heated with H2S04, it is decomposed, yielding HN03 and hydrosodic sulphate : H2S04 4- NaN03 = HNaS04 4- HNOa. This reaction is that used for obtaining HNO3. Sulphates.—Monosodic sulphate—Hydrosodic sulphate—Acid sodium sulphate—Bisulphate—HNaSO,—120—crystallizes in long, four-sided prisms; is unstable and decomposed by air, H20 or alcohol, into H2S04 and Na2SG4. Heated to dull redness it is converted into sodium pyrosulphate, Na2S207, corresponding to Nordhausen sulphuric acid. Disodic Sulphate—So die sulphate—Neutral sodium sulphate— Glauber’s salt—Sodii sulphas (TJ. S.)—Sodae sulphas (Br.)—Na2 S04 + n Aq —142 + n 18—occurs in nature in solid deposits, and in solution in natural waters. It is obtained as a secondary prod- uct in the manufacture of HC1, by the action of H2S04 on NaCl, 180 MANUAL OF CHEMISTRY. the decomposition occurring according to the equation : 2 NaCI + H2SO4 = Na2S04 + 2 HC1, if the temperature be raised suffi- ciently. At lower temperatures, the monosodic salt is produced, with only half the yield of HC1: NaCl + H2S04 = NaHS04 + HCL 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 38° (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 super- saturated solution, from which it is deposited, the entire mass becoming solid, on contact with a small particle of solid matter. 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 metamorphosis 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 alkali metals. A considerable amount exists in the form of the alkaline salts of conjugate, monobasic, ether acids, which, on decomposition, yield an aromatic organic compound. The amount of H2S04 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 sulphis (U. S.)—Na2S03 4- 7 Aq—126 + 126—is formed by passing S02 over crystallized .Na2C03. It crystallizes in efflorescent, oblique prisms ; quite soluble in H20, forming an alkaline solution. It acts as a reducing agent. Sodium Thiosulphate—Sodium hyposulphite—Sodii hyposul- phis (TJ. S.)—Na2S203 + 5 Aq—158 + 90—is obtained by dissolving S in hot concentrated solution of Na2S03, and crystallizing. It forms large, colorless, efflorescent prisms ; fuses at45c (113° F.); very soluble in H20 ; insoluble in alcohol. Its solutions precipi- tate alumina from solutions of A1 salts, without precipitating Fe or Mn ; they dissolve many compounds insoluble in H20 ; cuprous hydrate, iodids of Pb, Ag and Hg, sulphates of Ca and Pb. It acts as a disinfectant and antiseptic. H2S04 and most other acids decompose Na2S203 according to the equation : Na2S203 + II2S04 = Na2S04 + S02 + S + H20. Oxalic, and a few other acids, de- compose the thiosulphate with formation of H2S as well as S02 and S. Silicates.—Quite a number of silicates of Na are known. If SODIUM. 181 silica and be fused together, the residue extracted with H2O, 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— NaaPOi + 12 Aq—164 + 216—is obtained by adding XiaHO to diso- dic phosphate solution, and crystallizing. It forms six-sided prisms ; quite soluble in Ha0. Its solution is alkaline, and, on exposure to air, absorbs COa, with formation of HNaaPOi and ]N aaOOa. Disodic Phosphate—Hydro-disodic phosphate—Neutral sodium phosphate—Phosphate of soda—Sodii phosphas (U. S.)—Sodse phosphas (Br.)—HNa2PO, + 12 Aq—142 + 216—is obtained by con- verting tricalcic phosphate into monocalcic phosphate, and de- composing that salt with sodium carbonate: Ca(P04Ha)a + 2NaaC03 = CaC03 + HaO + COa + 2HNaaP04. 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 effloresces in air, and parts with 5 Aq; and is very soluble in HaO. The salt with 7 Aq is not efflorescent, and less soluble in HaO. Its solutions are faintly alkaline. Monosodic Phosphate—Acid sodium phosphate—HaNaPO, + Aq —120+18—crystallizes in rhombic prisms; forming acid solu- tions. At 100° (212° F.) it loses Aq ; at 200° (392° F.) it is converted into acid pyrophosphate, NaaH3PaOT ; and at 204° (399°.2 F.) into the metaphosphate, _NaP03. Physiological.—All the sodium phosphates exist, accom- panied by the corresponding K salts, in the animal economy. The disodic and dipotassic 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 car- nivora than in those of the herbivora. In the blood, in which the Na salt predominates in the plasma, and the K salt in the corpuscles, they serve to maintain an alkaline reaction. With strictly vegetable 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 monopotassic phosphates exist in the urine, the former predominating, and to their presence the acid reac- tion of that fluid is largely due. They are produced by decom- position of the neutral salts by uric acid. The urine of the her- bivora, 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 oxida- tion of phosphorized organic substances, the lecithins. 182 MANUAL OF ClIEMISTKY. Disodic Tetraborate—Sodium pyroborate—Borate of sodium— Borax—Tinoal—Sodii boras (TJ. S.)—Borax (Br.)—Na2B ,0, +10 Aq —202+180—is prepared by boiling boric acid with Na2C03 and crystallizing. It 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 be- comes anhydrous ; and, on cooling, leaves a transparent, glass- like mass. When fused, it is capable of dissolving many metallic oxids, forming variously colored masses, hence its use as a flux and in blowr-pipe analysis. Sodium Hypochlorite—NaCIO—74.5—only known in solution— Liq. sodae chloratse (U. S. ; Br.) or Labarraque’s solution—ob- tained by decomposing a solution of chlorid of lime by Na2C03. It is a valuable source of Cl, and is used as a bleaching and dis- infecting agent. Sodium Manganate—Na2MnO4 + 10 Aq—164+180—faintly col- ored crystals, forming a green solution with H20—Condy’s green disinfectant. Sodium Permanganate—Na2Mn208—282—prepared in the same way as the K salt (q. v.), which it resembles in its properties. It enters into the composition of Condy’s fluid, and of “chloro- zone,” which contains Na2Mn2Oe and NaCIO. Sodium Acetate—Sodii acetas (U. S.)—Sodae acetas (Br.)— NaC2Ha02+3Aq—82+54—crystallizes in large, colorless prisms ; acid and bitter in taste ; quite soluble in H20 ; soluble in alco- hol ; 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 H2SCb, yields glacial acetic acid. Carbonates.—Three are knowui : Na2C03 ; HNaC03, and H2Na4 (C03)3. Disodic Carbonate — Neutral carbonate — Soda — Sal soda— Washing soda—Soda crystals—Sodii carbonas (TJ. S.)—Sodee carbonas (Br.)—Na2CO3 + 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 native fluorid of Na and Al. Leblanc's process, in its present form, consists of three dis- tinct processes : (1.) The conversion of XaCl into the sulphate, by decomposition by H2S04. (2.) The conversion of the sulphate into carbonate, by heating a mixture of the sulphate with cal- cium carbonate and charcoal. The product of this reaction, knovrn as black ball soda, is a mixture of sodium carbonate, with charcoal and calcium sulphid and oxid. (3.) The purification of the product obtained in (2). The ball black is broken up, disin- tegrated by steam, and lixiviated. The solution on evaporation yields the soda salt or soda of commerce. SODIUM. Of late years Leblanc’s process has been in great part replaced by Solvay’s method, or the ammonia process, which is more eco- nomical, and yields a purer product. In this process sodium clilorid and ammonium bicarbonate react upon each other, with production of the sparingly soluble sodium bicarbonate, and the very soluble ammonium chlorid. The sodium bicarbonate is then simply collected, dried, and heated, when it is decomposed into Na2C03, H20, and C02. The anhydrous carbonate, Sodii carbonas exsiccatus (U. S.), Na2C03, is formed, as a white powder, by calcining the crystals. It fuses at dull redness, and gives off a little C03. It combines with and dissolves in H20 with elevation of temperature. The crystalline sodium carbonate, Na2CO3 + 10 Aq, forms large rhombic crystals, which effloresce rapidly in dry air ; fuse in their Aq at 34° (93°.2 F.); are soluble in H20, most abundantly at 38° (100 .4 F.). The solutions are alkaline in reaction. Monosodic Carbonate—Hydrosodic carbonate—Bicarbonate of soda—Acid carbonate of soda—Vichy salt—Sodii bicarbonas (U. S.)—Sodee bicarbonas (Br.)—NaHC03—84—exists in solution in many mineral waters. It is obtained by the action of C02 upon the disodic salt in the presence of H20 ; or, as above described, by the Solvay method. It crystallizes in rectangular prisms, anhydrous and permanent in dry air. In damp air it gives off C02, and is converted into the sesquicarbonate, Xa4H2(C03)3. When heated, it gives off C02 and H20, and leaves the disodic carbonate. Quite soluble in water; above 70° (158° F.) the solution gives off C02. The solu- tions 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 car- bonates are produced by the incineration 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 alkali metals, is taken. The car- bonates in the blood are both the mono- and disodic, and potas- sic; 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 crystalline on standing. (3.) 184 MANUAL OF CHEMISTRY. Periodic acid in excess : white ppt., in not too dilute solutions. (4.) Colors the Bunsen flame yellow, and shows a brilliant double line at A = 5895 and 5889 (Fig. 16, No. 2). POTASSIUM. Symbol — K (KALIUM) — Atomic weight = 39 — Molecular weight — 78 (?)—Sp. gr. — 0.865—Fuses at 62°.5 (144°.5 F.)—Boils at 667° (1233° 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 oxid or hydrate, and frequently ignites, burning with a violet flame. It must, therefore, be kept under naphtha. It decomposes H20, or ice, with great energy, the heat of the reaction igniting the liber- ated II. It combines with Cl with incandescence, and also unites directly with S, P, As, Sb, and Sn. Heated in C02 it is oxidized, and liberates C. Oxids.—Three are known : K20 ; K202; and K204. Potassium Hydrate—Potassium lxydroxid—Potash—Potassa— Common caustic—Potassa (U. S.)—Potassa caustica (Br.)-KHO— 56—is obtained by a process similar to that used in manufactur- ing NaHO. It is purified by solution in alcohol, evaporation and fusion in a silver basin, and casting in silver moulds—potash by alcohol; it is then free from KC1 and K2S04, but contains small quantities of K2C03, 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 red- ness ; 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 K2C03. Its solu- tions dissolve Cl, Br, I, S, and P. It decomposes the ammoniacal 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 leucin, tyrosin, etc. It oxidizes the carbohy- drates with formation of potassium oxalate and carbonate. It decomposes the fats with formation of soft soaps. Sulphids.—Five are known : K2S, K2S2, K2S3, K2S4, and K2Ss; also a sulphydrate : KHS. POTASSIUM. 185 Potassium Monosulphid—K,S—110—is formed by the action of KHO on KHS. Potassium Disulphid—KaSa—142—is an orange- colored solid, formed by exposing an alcoholic solution of KHS to the air. Potassium Trisulphid—KjS3—174—a brownish-yellow mass, obtained by fusing together K3C03 and S in the propor- tion : 4KaCO*+10S = S04Ks-t-3KaS3-t-4C0». Potassium Penta- sulphid—KaSa—288—is formed, as a brown mass, when K2C03 and S are fused together in the proportion : 4KaC034-16S = 4COa -f-SKaSg+KiSCh. Liver of Sulphur—hepar sulphuric—potassii sulphuratum (U. S.; Br.)—is a mixture of KaS3 and KaS5. Potassium Sulphydrate—KHS-72—is formed by saturating a solution of KHO with HaS. Potassium Chlorid.—Sal digestivum Sylvii—KC1—74.5—exists in nature, either pure or mixed with other ehlorids ; principally as carnallite, KOI, MgCla + 6 Aq. It crystallizes in anhydrous, per- manent cubes, soluble in HaO. Potassium Bromid—Potassii bromidum (TJ. S. ; Br.)—KBr—119 —is formed, either by decomposing ferrous bromid by KaC03, or by dissolving 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 HaO, sparingly so in alcohol. It is decom- posed by Cl with liberation of Br. Potassium Iodid—Potassii iodidum (TJ. S. ; Br.)—KI—160—is obtained by saturating KHO solution with I, evaporating, and calcining the resulting mixture of iodid and iodate with charcoal. It frequently contains iodate and carbonate. It crystallizes in cubes, transparent if pure ; permanent in air ; anhydrous ; sol- uble in H20, and in alcohol. It is decomposed by Cl, HN03 and HNOa, with liberation of I. It combines with other iodids to form double iodids. Its solutions dissolve iodin and many me- tallic iodids. Potassium Nitrate—Nitre—Saltpetre—Potassii nitras (TJ. S.)— Potassae nitras (Br.)—KN03—101—occurs in nature, and is pro- duced artificially, as a result of the decomposition of nitrogenized organic substances. It is usually obtained by decomposing native NaNOs by boiling solution of KaC03 or KC1. It crystallizes in six-sided, rhombic prisms, grooved upon the surface ; soluble in HaO, with depression of temperature ; more soluble in HaO containing NaCl; very sparingly soluble in alcohol; fuses at 850’ (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 ox ids. It is a valuable oxidant at high temperatures ; heated with charcoal it deflag- rates. 186 MANUAL OF CHEMISTRY. Gunpowder is an intimate mixture of KN03 with S and C, in such proportion that the KNOa yields all the O required for the combustion of the S and C. Potassium Chlorate—Potassii chloras (U. S.)—Potassae chloras (Br.)—KClOa—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 trans- parent, anhydrous plates; soluble in H20 ; 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 decomposed into KC1 and O : 2KC103 = KC104 + KC1 + 02 and KC104 = KC1 4- 202. It is a valuable source of O, and a more active oxidant than KN03. When mixed with readily oxidizible substances, C, S, P, sugar, tannin, resins, etc., the mixtures explode when subjected to shock. With strong H2S04 it gives off C1204, an explosive yellow gas. It is decomposed by HNOs with formation of KN03, KC104, and liberation of Cl and O. Heated with HC1 it gives off a mixture of Cl and C1204, the latter acting as an energetic oxidant in solutions in which it is generated. Potassium Hypochlorite—KC10—90.5—is formed in solution by imperfect saturation of a cooled solution of KHO with hypo- chlorous acid. An impure solution is used in bleaching : Javelle water. Sulphates.—Dipotassic sulphate—Potassium sulphate—Potassii sulphas (U. S.)—Potassae sulphas (Br.)—K SO,—174—occurs na- tive ; 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 1I20. Monopotassic Sulphate—Hydropotass i c sv Iph ate— Acid sv Iph ate —KHSO,—1B6—is formed as a by-product in the manufacture of HN03. When heated it loses H20, and is converted into the pyrosulphate. K2S207, which, at a higher temperature, is decom- posed into Iv2S04 and S03. Dipotassic Sulphite—Potassicsulphite—Potassii Sulphis (U.S.)— KjSOa—158—is formed by saturating solution of K2CG3 with S02, and evaporating over H2S04. It crystallizes in oblique rhoinbo- liedra; soluble in H20. Its solution absorbs O from air, with formation of K2S04. Potassium Dichromate—Bichromate of potash—Potassii bi- chromas (U. S.)—Potassae bichromas (Br.)—K2Cr207—294.8—is formed by heating a mixture of chrome iron ore with KNOs, or K2C03 in air ; extracting with H20 ; neutralizing with dilute H2S04 ; and evaporating. It forms large, reddish-orange colored prismatic crystals ; soluble in H20 ; fuses below redness, and at POTASSIUM. a higher temperature is decomposed intoO, potassium chromate, and sesquioxid of chromium. Heated with HC1, it gives off Cl. Potassium Permanganate—Potassii permanganas (TJ. S.)—Po- tassae permanganas (Br.)—K.Mn,0P—314—is obtained by fusing a mixture of manganese dioxid, KHO, and KC103, and evapora- ting the solution to crystallization ; KsMn04 and KC1 are first formed ; on boiling with H20, tliemanganate is decomposed into K2Mna08, KHO, and MnOa. It crystallizes in dark prisms, almost black, with greenish re- flections, which yield a red powder when broken. Soluble in HaO, communicating to it a red color, even in very dilute solu- tion. It is a most valuable oxidizing agent. With organic mat- ter its solution is turned to green, by the formation of the man- ganate, or deposits the brown sesquioxid of manganese, accord- ing to the nature of the organic substance. In some instances the reaction takes place best in the cold, in others under the in- fluence of heat; in some better in acid solutions, in others in alka- line solutions. Mineral reducing agents act more rapidly. Its oxidizing powers render its solutions valuable as disinfectants. Potassium Acetate—Potassii acetas (U. S.)—Potassae acetas(Br.) —KC2H3O2—110—exists in the sap of plants ; and it is by its cal- cination that the major part of the carbonate of wood ashes is formed. It is prepared by neutralizing acetic acid with K3C03 or KHCCh. It forms crystalline needles, deliquescent, and very soluble in H20 ; less soluble in alcohol. Its solutions are faintly alkaline. Carbonates.—Dipotassic Carbonate—Potassic Carbonate—Salt of tartar—Pearl ash—Potassii Carbonas (TJ. S.)—Potassae car bonas (Br.)—K.CO;i—138—exists in mineral waters, and in the animal economy. It is prepared industrially, in an impure form, known as potash or pearlash, from wood ashes, from the molasses of beet-sugar, and from the native Stassfurth chlorid. It is ob- tained 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 K2C03, called black flux; on extracting which with H20, a pure carbon- ate, 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. Monopotassic Carbonate—Hydropotassic carbonate—Bicarbon- ate—Potassii bicarbonas—(TJ. S.)—Potassae bicarbonas (Br.)— HKCO:i—100 —is obtained by dissolving K2C03 in H20, and sat- urating the solution with C02. It crystallizes in oblique rhom- bic prisms, much less soluble than the carbonate. In solution, it 188 MANUAL OF CHEMISTRY. 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 saleeratus, is this or the corresponding ]\Ta salt, usually the latter. Its exten- sive 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 dioxid and dipotassic (or disodic) carbonate, the latter producing disturbances of digestion by its strong alkaline reac- tion. Monopotassic oxalate—Hydropotassic oxalate—Binoxalate of jiotash—HKC20i—128—forms transparent, soluble, acid needles. It occurs along with the quadroxalate HKC204,H2C204+2 Aq, in salt of lemon or salt of sorrel, used in straw bleaching, and for the removal of ink-stains, etc. It closely resembles Epsom salt in appearance, and lias been fatally mistaken for it. Tartrates.—Dipotassic tartrate—Potassic tartrate—Soluble tar- tar—Neutral tartra te of potash—Potassii tartras (U. S.)—Potassae tartras (Br.)—K2C4HiO0—226—is prepared by neutralizing the hydropotassic salt with potassium carbonate. It forms a white, crystalline powder, very soluble in H20, the solution being dex- trogyrous, [a]D = +28°.48 ; soluble in alcohol. Acids, even acetic, decompose its solution, with precipitation of the monopotassic salt. Monopotassic tartrate—Hydropotassic tartrate—Cream of tartar —Potassii bitartras (U. S.)—Potassae bitartras (Br.)—HKC,H,06 —188.—During the fermentation of grape juice, as the porportion of alcohol increases, crystalline crusts collect in the cask. These constitute the crude tartar, or argol, of commerce, which is com- posed, in great part, of monopotassic tartrate. The crude prod- uct is purified by repeated crystallization from boiling H20 ; digesting the purified tartar with HC1 at 20° (68° F.) ; washing with cold H20, and crystallizing from hot H20. It crystallizes in hard, opaque (translucent when pure), rhom- bic 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 oxids with formation of double tar- trates. When boiled with antimony trioxid, it forms tartar emetic. It is used in the household, combined with monosodic carbon- ate, in baking, the two substances reacting upon each other to form Rochelle salt, with liberation of carbon dioxid. Baking Powders are now largely used as substitutes for yeast in the manufacture of bread. Their action is based upon the de- POTASSIUM. 189 composition of HNaC03 by some salt having an acid reaction, or by a weak acid. In addition 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, or acid phosphates. Sometimes am- monium sesquicarbonate is used, in whole or in part, in place of sodium carbonate. The reactions by which the 04)a and CaC03, and in many vegetable structures. The element is a hard, yellow, very ductile, and malleable metal; fusible at a red heat; not sensibly volatile. In dry air it is not altered, but is converted into CaH30a in damp air; decom- poses HaO; burns when heated in air. Calcium Monoxid—Quick lime—Lime—Calx (TJ. S.; Br.)—CaO— 56—is prepared by heating a native carbonate (limestone); or, when required pure, by heating a carbonate, prepared by precip- itation. It occurs in white or grayish, amorphous masses; odorless; alkaline; caustic; almost infusible; sp. gr. 2.3. With HaO 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 CaC03, CaHaOa. 198 MANUAL OF CHEMISTRY. Calcium Hydrate—Slacked lime—Calcis hydras (Br.)—CaH202 —74—is formed by the action of H20 on CaO. If the quantity of H20 used be one-third that of the oxid, 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 H2G be greater, a creamy, or milky liquid remains, cream or milk of lime; a solution holding an excess in suspension. With a suffi- cient quantity of H20 the hydrate is dissolved to a clear solution, which is lime water—Liquor calcis (TJ. S.; Br.). The solubility of CaH202 is diminished by the presence of alkalies, and is in- creased by sugar or mannite: Liq. calc, saccharatus (Br.). Solu- tions of CaH202 absorb C02 with formation of a white deposit of CaC03. Calcium Chlorid—Calcii chloridum (TJ. S.; Br.)—CaCl2—111—>is obtained by dissolving marble in HC1: CaC03-f-2HCl=CaCl2-|- H20—(-C02. It is bitter; deliquescent; very soluble in H20; crys- tallizes with 0 Aq, which it loses when fused, leaving a white, amorphous mass; used as a drying agent. Chloride of Lime—Bleaching powder—Calx chlorata (TJ.S.; Br.) —is a white or yellowish, hygroscopic powder, prepared by pass- ing Cl over CaH202, maintained in excess. It is bitter and acrid in taste; soluble in cold H20; decomposed by boiling H20, and by the weakest acids, with liberation of Cl. It is decomposed by C02, with formation of CaC03, and liberation of liypochlorous acid, if it be moist; or of Cl, if it be dry. A valuable disinfectant. Bleaching powder was formerly considered as a mixture of cal- cium chlorid and hypochlorite, formed by the reaction: 2CaO-|- 2Cl2=CaCl2-|-Ca(C10)2, but it is more probable that it is a definite compound having the formula CaCl(OCl), which is decomposed by H20 into a mixture of CaCl2 and Ca(C10)2; and by dilute HN03 or H2SO.i with formation of HC10. Calcium Sulphate—CaS04—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 H20, more soluble in H20 containing free acids or chlorids. 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 con- version of the anhydrous into the crystalline, hydrated salt. The ordinary plastering should never be used in hospitals, as, by rea- son 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 disinfectants. Plaster sur- 199 CALCIUM. faces 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: Ca3(P04)2; Ca2(HP04)2, and Ca(H2P04)2. Tricalcic Phosphate—Tribasic or neutral phosphate — Bone phosphate—Calcii phosphas praecipitatus (U. S.)—Calcis phosphas (Br.)—Ca3(P04)2—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, fdtering, and pre- cipitating with IsH4HO; or by double decomposition between CaCl2 and an alkaline phosphate. When freshly precipitated it is gelatinous; when dry, a light, white, amorphous powder; almost insoluble in pure II20; soluble to a slight extent in H20 contain- ing ammoniacal salts, or NaCl or NaNOs; readily soluble in dilute acids, even in H20 charged with carbonic acid. It is decomposed by H2S04 into CaS04 and Ca(H2P04)2. Bone-ash is an impure form of Ca3(P04)2, obtained by calcining bones, and used in the manufacture of P and of superphosphate. Dicalcic Phosphate—Ca.(HPO,)2-(-2Aq—272—j-36—is a crystal- line, insoluble salt; formed by double decomposition between CaCl2 and HNa2P04 in acid solution. Monocalcic Phosphate—Acid calcium phosphate—Superphos- phate of lime—Ca(H2PO,)2—234—exists in brain tissue, and in those animal liquids whose reaction is acid It is also formed when Ca3(P04)2 is dissolved in an acid, and is manufactured, for use as a manure, by decomposing bone-ash with H2S04. It crys- tallizes in pearly plates; very soluble in H20. Its solutions are acid. Physiological.—All three calicum phosphates, accompanied by the corresponding Mg salts, exist in the animal economy. The tricalcic salt occurs in all the solids of the body, and in all fluids not having an acid reaction, being held in solution in the latter by the presence of chlorids. In the fluids it is present in very small quantity, except in the milk, in which it is comparatively abundant ; 2.5 to 3.95 parts per 1,000 in human milk, and 1.8 to 3.87 parts per 1,000 in cow’s milk; constituting about 70 per cent, of the ash. The bones contain about 35 parts of organic matter, combined with G5 parts of mineral material. The average of human bone-ash is: Ca3(P04)2—83.89; CaC03—13.03; Ca, combined with Cl, F, and organic acids—0.35; F—0.23; Cl—0.18. The aver- age quantity of Ca3(P04)2 in male adult bones is 57 per cent.; that of CaC03, 10 per cent.; and that of Mg3(P04)2, 1.3 per cent. In pathological conditions the composition of bone is modified as shown in the following table: 200 MANUAL OF CHEMISTRY. Analyses of Bones. male. ; fe- CS o •3 2 3% .38 • 3 $ lacia, rerte- u P 01 2 u p S male, ver- 3 b£ a 0) A In 100 parts. ealtliy aged 4 mur. steom male, a femur. steom male, a femur. steom child; bra. « 2 o achitis merus. cc 2 aries, f aged 4 tebra. 2 8 o o H O O O (2 M o a 48 83 32 54 75.22 72 20 J- 81.12 j 35.69 41.42 19.58 29.18 4.15 6.12 7.20 3.00 8.30 1.22 Tricalcic phosphate 56.9 17.56 53.25 12.50 14.78 1 00 15.60 [51.68 44.05 72.63 Calcium carbonate ioi 3.04 7.49 3.20 3.00 2.66 5.44 3 45 4.03 Trimagnesic phosphate. 1.3 0.23 1.22 0.92 0.80 * 3.43 1.02 1.93 0 37 1 35 1 98 1 02 0.62 0.91 1.70 0.01 Organic matter 35.8 78.01 36.69 81.34 79.40 81.12 38.69 49.78 20.80 Ash 64.2 21.20 63.31 19.66 20.00 18.88 01.31 50.22 79.20 * Included in tricalcic P P C$ o3 . 5 'd p 3 >> M 2 d u 2 phosphate. s P 8 s- 03 U) a crS'S g as o §■31 o ci a o 6 > s S « « 3 > The teeth consist largely of Ca3(P04)2; the dentin of human molars containing 66.72 per cent., and the enamel 89.82 per cent. From the urine, tricalcic phosphate is frequently deposited, either in the form of an amorphous, granular sediment, or as calculi. The dicalcic salt occurs occasionally in urinary sedi- ments, in the form of needle-shaped crystals, arranged in rosettes, and also in urinary calculi. The monocalcic salt is always pres- ent in acid urine, constituting, with the corresponding mag- nesium salt, the earthy phosphates. The total elimination of H3PO4 by the urine is about 2.75 grams (42.5 grains) in 24 hours; of which two-thirds are in combination with Na and K; and one- third with Ca and Mg. The hourly elimination follows about the same variation as that of the chlorids. The total elimination is greater with animal than with vegetable food; is diminished dur- ing pregnancy; and is above the normal during excessive mental work. The elimination of earthy phosphates is greatly increased in osteomalacia, often so far that they are in excess of the alkaline phosphates. So long as the urine is acid, it contains the soluble acid phos- phates. When the reaction becomes alkaline, or even on loss of C02 by exposure to air, the acid phosphate is converted into the insoluble Ca3(P04)2. Alkaline urines are, for this reason, almost always turbid, and become clear on the addition of acid. It is in such urine that phosphatic calculi are invariably formed, usually about a nucleus of uric acid, or of a foreign body. If the alka- linity be due to the formation of ammonia, the trimagnesic phos- phate is not formed, but ammonio-magnesian phosphate (q.v.). Quantitative determination of phosphates in urine.—A process CALCIUM. 201 for determining the quantity of phosphates in urine is based upon the formation of the insoluble uranium phosphate, and upon the production of a brown color when a solution of a uranium salt is brought in contact with a solution of potassium ferrocyanid. Four solutions are required: (1) a standard solution of disodic phosphate, made by dissolving 10.085 grams of crystallized, non- eftloresced HNa2P04 in H20, and diluting to a litre; (2) an arid solution of sodium acetate, made by dissolving 100 grams sodium acetate in H20, adding 100 c.c. glacial acetic acid, and diluting with H20 to a litre; (3) a strong solution of potassium ferrocy- anid; (4) a standard solution of uranium acetate, made by dis- solving 20.3 grams of yellow uranic oxid in glacial acetic acid, and diluting with H20 to nearly a litre. Solution 1 serves to deter- mine the true strength of this solution, as follows: 50 c.c. of Solu- tion 1 are placed in a beaker, 5 c.c. of Solution 2 are added, the mixture heated on a water-bath, and the uranium solution grad- ually added, from a burette, until a drop from the beaker pro- duces a brown color when brought in contact with a drop of the ferrocyanid solution. At this point the reading of the burette, which indicates the number of c.c. of the uranium solution, cor- responding to 0.1—P205, is taken. A quantity of H20, determined by calculation from the result thus obtained, is then added to the remaining uranium solution, such as to render each c.c. equiva- lent to 0.005 gram P205. To determine the total phosphates in a urine: 50 c.c. are placed in a beaker, 5 c.c. sodium acetate solution are added; the mix- ture is heated on the water-bath, and the uranium solution de- livered from a burette, until a drop, removed from the beaker and brought in contact with a drop of ferrocyanid solution, pro- duces a brown tinge. The burette reading, multiplied by 0.005, gives the amount of P205 in 50 c.c. urine ; and this, multiplied by the amount of urine passed in 24 hours, gives the daily elimi- nation. To determine the earthy phosphates, a sample of 100 c.c. urine is rendered alkaline with NH4HO, and set aside for 12 hours. The precipitate is then collected upon a filter, washed with ammoni- acal water, brought into a beaker, dissolved in a small quantity of acetic acid; the solution diluted to 50 c.c. with H20, treated with 5 c.c. sodium acetate solution, and the amount of P205 de- termined as above. Calcium Carbonate—CaCO:,—100—the most abundant of the nat- ural compounds of Ca, exists as limestone, calcspar, chalk, mar- ble, Iceland spar, and arragonite ; and forms the basis of corals, shells of Crustacea and of molluscs, etc. The precipitated chalk—Calcii carbonas prsecipitata (U. S. ; Br.) —is prepared by precipitating a solution of CaCl2 with one of 202 MANUAL OF CHEMISTRY. Na2COs. Prepared chalk—Creta praeparata (U. S.; Br.)—is native chalk, purified by grinding with H20, diluting, allowing the coarser particles to subside, decanting the still turbid liquid, col- lecting, and drying the finer particles. A process known as elutriation. It is a white powder, almost insoluble in pure H20; much more soluble in H20 containing carbonic acid, the solution being re- garded as containing monocalcic carbonate H2Ca(COs)2. At a red heat it yields C02 and CaO. It is decomposed by acids with liberation of C02. Physiological.—Calcium carbonate is much more abundant in the lower than in the higher forms of animal life. It occurs in the egg-shells of birds, in the bones and teeth of all animals; in solution in the saliva and urine of the herbivora, and deposited in the crystalline form, as otoliths, in the internal ear of man. It is deposited pathologically in calcifications, in parotid calculi, and occasionally in human urinary calculi and sediments. Calcium Oxalate—Oxalate of lime—CaC204—128—exists in the sap of many plants, and is formed as a white, crystalline precipi- tate, by double decomposition, between a Ca salt and an alkaline oxalate. It is insoluble in H20, acetic acid, or NH4HO; soluble in the mineral acids and in solution of H2NaP04. Physiological.—Calcium oxalate is taken into the body in vegetable food, and is formed in the economy, where its produc- tion is intimately connected with that of uric acid. It occurs in the urine, in which it is increased in quantity when large amounts of vegetable food are taken; when sparkling wines or beers are indulged in; and when the carbonates of the alkalies, lime-water and lemon-juice, are administered. It is deposited as a urinary sediment in the form of small, brilliant octahedra, hav- ing the appearance of the backs of square letter-envelopes; or in dumb-bells. It is usually deposited from acid urine, and accom- panied by crystals of uric acid. Sometimes, however, it occurs in urines undergoing alkaline fermentation, in which case it is ac- companied by crystals of ammonio-magnesian phosphate. The renal or vesical calculi of calcium oxalate, known as mul- berry calculi, are dark brown or gray, very hard, occasionally smooth, generally tuberculated, soluble in HC1 without efferves- cence; and when ignited, they blacken, turn white, and leave an alkaline residue. (See oxalic acid.) Analytical Characters.—(1.) Ammonium sulphydrate: nothing, unless the Ca salt be the phosphate, oxalate or fluorid, when it forms a white ppt. (2.) Alkaline carbonates: white ppt.; not prevented by the presence of ammoniacal salts. (3.) Ammonium oxalate: white ppt.; insoluble in acetic acid; soluble in HC1, or STRONTIUM, BARIUM. 203 HNOs. (4.) Sulphuric acid: white ppt., either immediately or on dilution with three volumes of alcohol; very sparingly soluble in H20; insoluble in alcohol; soluble in sodium hyposulphite solu- tion. (5.) Sodium tungstate: dense white ppt., even from dilute solutions. (6.) Colors the flame of the Bunsen burner reddish- yellow, and exhibits a spectrum of a number of bright bands, the most prominent of which are: /.=6265, 6202, 6181, 0044, 5982, 5933, 5543, and 5517. STRONTIUM. Symbol=Sr—Atomic weight=SJA—Sp. gr. =2.54. An element, not as abundant as Ba, occurring principally in the minerals strontianite (SrCOs) and celestine (SrS04). Its com- pounds resemble those of Ca and Ba. Its nitrate is used in mak- ing red fire. Analytical characters.—(1.) Behaves like Ba with alkaline car- bonates and Na2HP04. (2.) Calcium sulphate: a white ppt. which forms slowly; accelerated by addition of alcohol. (3.) The Sr compounds color the Bunsen flame red, or, as observed through blue glass, purple or rose color. The Sr flame gives a spectrum of many bands, of which the most prominent are: *=6694, 6664, 6059, 6031, 4607. BARIUM. Symbol—Ha.—Atomic weight—136.8—Molecular weights273.6 (?) —Sp. gr. —4.0—Discovered by Davy, 1808—Name from [iapvg— heavy. Occurs only in combination, principally as heavy spar (BaS04) and witherite (BaC03). It is a pale yellow, malleable metal, quickly oxidized in air, and decomposing H20 at ordinary tem- peratures. Oxids.—Barium Monoxid—Baryta—BaO—152.8—is prepared by calcining the nitrate. It is a grayish-wliite or white, amorphous, caustic solid. In air it absorbs moisture and C02, and combines with HaO as does CaO. Barium Dioxid—Barium peroxid—Ba02—1C8.8—is prepared by heating the monoxid in O. It is a grayish-white, amorphous solid. Heated in air it is decomposed: Ba02=Ba0-f-0. Aqueous acids dissolve it with formation of a barytic salt and H202. Barium Monohydrate—BaH202—170.8—is prepared by the ac- tion of H20 on BaO. It is a white, amorphous solid, soluble in H20. Its aqueous solution, baryta water, is alkaline, and absorbs C02, with formation of a white deposit of BaCOs. Barium Chlorid—BaCl2-f-2A.q—207.8-f36—is obtained by treating BaS or BaC03 with HC1. It crystallizes in prismatic plates, per- manent in air, soluble in H20. 204 MANUAL OF CHEMISTRY. Barium Nitrate—Ba(N03)2—260.8—is prepared by neutralizing HXOs with BaC03. It forms octahedral crystals, soluble in H20. Barium Sulphate—BaSO,—232.8—occurs in nature as heavy spar, and is formed as an amorphous, white powder, insoluble in acids, by double decomposition between a Ba salt and a sulphate in solution. It is insoluble in H20 and in acids. It is used as a pig- ment, permanent white. Barium Carbonate—BaCO:i—196.8—occurs in nature as witherite, and is formed by double decomposition between a Ba salt and a carbonate in alkaline solution. It is a heavy, amorphous, white powder, insoluble in H20, soluble with effervescence in acids. Analytical Characters.—(1.) Alkaline carbonates: white ppt., in alkaline solution. (2.) Sulphuric acid, or calcium sulphate: white ppt.; insoluble in acids. (3.) Sodium phosphate: white ppt.; sol- uble in HX03. (4.) Colors the Bunsen flame greenish-yellow, and exhibits a spectrum of several lines, the most prominent of which are : a=6108, 6044, 5881, 5536. Action on the Economy.—The oxids and hydrate act as corro- sives, by virtue of their alkalinity, and also as true poisons. All soluble compounds of Ba, and those which are readily converted into soluble compounds in the stomach, are actively poisonous. Soluble sulphates, followed by emetics, are indicated as antidotes. The sulphate, notwithstanding its insolubility in water is poison- ous to some animals. IV. MAGNESIUM GROUP. Each of these elements forms a single oxid—a corresponding basic hydrate, and a series of salts in which its atoms are bivalent. Magnesium—Zinc—Cadmium. MAGNESIUM. Symbol=Mg—Atomic weight=24—Molecular weight=48 (?)— JSp. gr.—1.75—Fuses at 1000° (1832° F.)—Discovered by Davy, 1808. Occurs as carbonate in dolomite or magnesian limestone, and as silicate in mica, asbestos, soapstone, meerschaum, talc, and in other minerals. It also accompanies Ca in the forms in which it is found in the animal and vegetable worlds. It is prepared by heating its clilorid with Na. It is a hard, light, malleable, ductile, white metal. It burns with great bril- liancy when heated in air (magnesium light), but may be distilled in H. The flash light used by photographers is a mixture of powdered Mg with an oxidizing agent, KC103 or KNO:t. It de- MAGNESIUM. 205 composes vapor of H20 when heated; reduces C02 with the aid of heat, and combines directly with Cl, S, P, As, and N. It dissolves in dilute acids, but is not affected by alkaline solutions. Magnesium Oxid—Calcined magnesia—Magnesia (TJ. S.; Br.)— MgO—40—is obtained by calcining the carbonate, hydrate, or nitrate. It is a light, bulky, tasteless, odorless, amorphous, white powder; alkaline in reaction; almost insoluble in H20; readily soluble without effervescence in acids. Magnesium Hydrate—MgH.,Oa—58—occurs in nature, and is formed when a solution of a Mg salt is precipitated with excess of NaHO, in absence of ammoniacal salts. It is a heavy, white powder, insoluble in H20; absorbs C02. Magnesium Chlorid—MgCl2—95—is formed when MgO or MgC03 is dissolved in HC1. It is an exceedingly deliquescent, soluble substance, which is decomposed into HC1 and MgO when its aqueous solutions are evaporated to dryness. Like all the soluble Mg compounds it is bitter in taste, and accompanies the sulphate and bicarbonate in the bitter waters. Magnesium Sulphate—Epsom salt—Sedlitz salt—Magnesii sul- phas (TJ. S.)—Magnesise sulphas (Br.)—MgS04-}-7 Aq—120—(-126— exists in solution in sea-water and in the waters of many mineral springs, especially those known as bitter waters. It is formed by the action of H2S04 on MgC03. It crystallizes in right rhombic prisms; bitter; slightly effervescent, and quite soluble in H20. Heated, it fuses and gradually loses 6 Aq up to 182° (269°.G F.); the last Aq it loses at 210° (410° F.). Phosphates.—Resemble those of Ca in their constitution and properties, and accompany them in the situations in which they occur in the animal body, but in much smaller quantity. Magnesium also forms double phosphates, constituted by the substitution of one atom of the bivalent metal for two of the atoms of basic hydrogen, of a molecule of phosphoric acid, and of an atom of an alkaline metal, or of an ammonium group, for the remaining basic hydrogen. Ammonio-Magnesian Phosphate—Triple phosphate—Mgi NH,) POk-f-6 Aq—137+108—is produced when an alkaline phosphate and NH 4HO are added to a solution containing Mg. When heated it is converted into magnesium pyrophosphate Mg2P2OT, in which form H3P04 and Mg are usually weighed in quantitative analysis. In the urine, alkaline phosphates and magnesium salts are al- ways present, and consequently when, by decomposition of urea, the urine becomes alkaline, the conditions for the formation of this compound are fulfilled. Being practically insoluble, espe- cially in the presence of excess of phosphates and of ammonia, it is deposited in crystals, usually tabular, sometimes feathery and stellate in form. When it is formed in the bladder, in the pres- 206 MANUAL OF CHEMISTRY. ence of some body to serve as a nucleus, the crystallization takes place upon the nucleus, and a fusible calculus is produced. Carbonates.—Magnesium Carbonate—Neutral carbonate—Mg C0y—84—exists native in magnesite, and, combined with CaC03, in dolomite. It cannot be formed, like other carbonates, by de- composing a Mg salt with an alkaline carbonate, but may be ob- tained by passing C02 through H20 holding tetramagnesic tricar bonate in suspension. Trimagnesic Dicarbonate—(MgC03)2MgH202+2Aq—226+36—is formed, in small crystals, when a solution of MgSCh is precipi- tated with excess of Na2C03, and the mixture boiled. Tetramagnesic Tricarbonate—Magnesia alba—Magnesii car- bonas (TJ. S.)—Magnesise carbonas (Br.)—3(MgC03 )MgH202+3Aq —310+54—occurs in commerce in light, white cubes, composed of a powder which is amorphous, or partly crystalline. It is pre- pared by precipitating a solution of MgSCh with one of Na2C03. If the precipitation occur in cold, dilute solutions (Magnesiae carbonas loevis, Br.), very little C02 is given off; a light, bulky precipitate falls, and the solution contains magnesium, probably in the form of the bicarbonate Mg(HC03)2. This solution, on standing, deposits crystals of the carbonate, MgC03+3Aq. If hot concentrated solutions be used, and the liquid be then boiled upon the precipitate, C02 is given off, and a denser, heavier pre- cipitate is formed, which varies in composition, according to the length of time during which the boiling is continued, and to the presence or absence of excess of sodium carbonate. The pharma- ceutical product frequently contains 4(MgC03),MgH202+4H20, or even 2(MgC03),MgH202+2H20. All of these compounds are very sparingly soluble in H20, but much more soluble in H20 containing ammoniacal salts. Analytical Characters.—(1.) Ammonium hydrate: voluminous, white ppt. from neutral solutions. (2.) Potash or soda: volumi- nous, white ppt. from warm solutions; prevented by the presence of NH4 salts, and of certain organic substances. (3.) Ammonium carbonate ; slight ppt. from hot solutions; prevented by the pres- ence of NHj salts. (4.) Sodium or potassium carbonate: white ppt., best from hot solution; prevented by the presence of ]STH( compounds. (5.) Disodic phosphate: white ppt. in hot, not too dilute solutions. (6.) Oxalic acid: nothing alone, but in presence of NH4HO, a white ppt.; not formed in presence of salts of NH ,. ZINC. ZINC. Symbols Zn —Atomic weight=tH2)i _ 2. The first term is HC = CH. Family II.—Cyclic or Closed Chain Hydrocarbons.—The com- pounds of this family all contain a “nucleus” or “ring,” in which every carbon atom is linked to at least two other carbon atoms, thus forming a “ cycle,” or closed chain. The number of possible groups in this series is very large. Representatives of the follow- ing are known : Group A — Paraffene Series — have the algebraic formula CnHm. This is the simplest form of cyclic hydrocarbon, each carbon atom exchanging a valence with its neighbor on each side. Some representatives of the group exist in petroleum and have been formed synthetically. They are isomeric with the terms of Group B, Family I. Group B — Terebenthic Series — have the algebraic formula CnH2n - 4. The lower terms of the series are not well known. Among the higher terms are a great number of isomeres existing in nature among the essential oils. Group C—Benzenic Series.—This series includes the most im- portant of the closed chain hydrocarbons, and their derivatives. They have the algebraic formula CnHan- e, and all contain the benzene nucleus C6H8, or some product of substitution thereof. The number of derivatives obtainable by substitution, by graft- ing together of two or more benzene nuclei, or by grafting of open-chain hydrocarbons, or of their derivatives, upon a benzol 228 MANUAL OF CHEMISTRY. nucleus is apparently unlimited. They are all very stable sub- stances. The other carbon compounds may be regarded as derived from the hydrocarbons by the substitution or addition of an atom or group of atoms in or upon the hydrocarbon, the character, or function of the substance so produced depending upon the char- acter and position of the substituted or added atom or group. This will be developed as we proceed. ACYCLIC HYDROCARBONS. 229 ACYCLIC HYDROCARBONS AND THEIR DERIVATIVES. FIRST SERIES OF HYDROCARBONS Series CnH2n + j. lowing: Name. Formula. Specific Gravity oil Liquid. Boiling-point. Centigrade. Methyl h yd rid ch3h Kthyl hyd rid c,h5h Propyl hydrid c3h7h Butyl hydrid c4h9h - 0.600 at 0° 0° Amyl hydrid CsHuH 0.628 at 18° 30° Hexyl hydrid • CeHnH 0.669 at 18° 68° Heptyl hydrid C: H i jH 0.690 at 18° 92°-94° Octyl hydrid c«h17h 0.726 at 185 116°-118° Nonyl hydrid c9h19h 0.741 at 18° 136°-138° Decyl hydrid CioHjiH 0.757 at 18° 158°-162° Undecyl hydrid CnHasH 0.766 at 18° 180°-182° Dodecyl hydrid C19H25H 0.778 at 18° 198°-200° Tridecyl hydrid c13h27h 0.796 at 18° 218°-220° Tetradecyl hydrid.... ChHJ9H 0.809 at 18D 2363-240° Pentadecyl hydrid C1sH31H 0.825 at 18° 258°-262° Hexadecyl hydrid c18h33h about 2802 The hydrocarbons of this series at present known are the fol They form an homologous series whose general formula is CnH271 + 2, and are known as paraffins from their stability {param — little, afflnis = affinity). The radicals CnH2n + i, of which they are the hydrids, are sometimes designated as the rad- icals of the monoatomic alcohols, or inonoatomic alcoholic rad- icals. 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 paraffins, or regularly formed series, in which each C atom is linked to two other C atoms. (2.) The isoparaffins, those in which one C atom is linked to three others. (3.) The neoparaffins, those in which two C atoms are each linked to three others. (4.) The mesoparaffins, those in wrhich one C atom is linked to four others. The constitution of these series is explained by the graphic formulae : 230 MANUAL OF CHEMISTRY. (1.) ch3 ch2 I ch2 I ch2 CHj I ch3 (2.) ch3 I H—C—CH3 ch2 ch2 ch-ch-oh Unknown, CH3\ CH3—C—CH,,OH CH3/ Unknown. Secondary amylic alcohols: CH3 CHjXpiJ ATT ch3—ch2/ch,u±1 Diethyl carbinol. CHaXpri CHa-CH3-CH2/' M’UH Methyl-propyl carbinol. 240 MANUAL OF CHEMISTRY. CH^CH>CH’0H ch3/ Tertiary amylic alcohol: Methyl-isopropyl carbinol. CH3\ CH3—C,OH CH3—CHS/ Methyl hydrate—Carhinol— Pyroxylic spirit—Methylic alcohol —Wood spirit—H,CH2OH—32—may be formed from marsh-gas, CH3H, by first converting it into the iodid, and acting upon this with potassium hydrate: CH3I-fKHO = KI-(-CH3HO. It is usu- ally 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 distillate is treated with quicklime and again distilled; the distillate treated with dilute H2S04; decanted and again distilled. The product, still quite impure, is the wood alcohol, wood naphtha, or pyroxylic spirit of commerce. The pure hydrate can only be obtained by decomposing a crystalline compound, such as methyl oxalate, and rectifying the product until the boiling-point is constant at 06°.5 (151°.7 F.). Pure methyl alcohol is a colorless liquid, having an ethereal and alcoholic odor, and a sharp, burning taste; sp. gr. 0.814 at 0°; boils at 66°.5 (151°.7 F.); burns with a pale flame, 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 ordi- nary circumstances, but in the presence of platinum-black it is oxidized, with formation of the corresponding aldehyde and acid, formic acid. Hot HN03 decomposes it with formation of nitrous fumes, formic acid and methyl nitrate. It is acted upon by H 2S04 in the same way as ethyl alcohol. The organic acids form methyl ethers with it. With HC1 under the influence of a gal- vanic current, it forms an oily substance having the composition C2H3C10. Methylated spirit is ethyl alcohol containing sufficient wood spirit to render it unfit for the manufacture of ardent spirits, by reason of the disgusting odor and taste which crude wood alcohol owes to certain empyreumatic products which it contains. Spirits so treated are not subject to the heavy duties imposed upon ordi- nary alcohol, and are, therefore, largely used in the arts and for the preservation of anatomical preparations. It contains one- ninth of its bulk of wood naphtha. MONOATOMIC ALCOHOLS. 241 Ethyl hydrate—Ethylic alcohol—Methyl Carbinol—Vimc al- cohol—Alcohol—Spirits of wine—C.H.HO—40. Preparation.—Industrially alcohol and alcoholic liquids are ob- tained 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 fermentation. 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 germination, roasted. During this growth there is de- veloped in the barley a peculiar nitrogenous principle called dias- tase. The starchy material is mixed with a suitable quantity of malt and water, and the mass maintained at a temperature of G5 - 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 dioxid and alcohol: 2C02. 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 pur- pose has been so far perfected that by a single distillation an alcohol of 90-95 per cent, can be obtained. —* 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 H40, and when pure or absolute alcohol is required, the commercial product must be mixed with some hygroscopic 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 originally applied to alcoholic fermentation, by reason of the bub- bling of the saccharine liquid caused by the escape of C05; sub- sequently 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 heterogeneous processes; and some writers distinguish between “ true ” and “ false ” fermentation. It is best, we believe, to limit MAN UAL OF C1IFMISTKY. the application of the term to those decompositions designated as true fermentations. Fermentation is a decomposition of an organic substance, pro- duced by the processes of nutrition of a low form of animal or vegetable life. The true ferments are therefore all organized beings, such as torula cerevisice, producing alcoholic fermentation; penicillium glaucum, producing lactic acid fermentation; and mycoderma aceti, producing acetic acid fermentation. 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, therefore, designated by the term cryptolysis. Diastase, pep- sin 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 at0°, 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 moist- ure from the air to such a degree that absolute alcohol only re- mains such for a very short time after its preparation. It is to this power of attracting KUO that alcohol owes its preservative power for animal substances. It is a very useful solvent, dissolv- ing a number of gases, most of the mineral and organic acids and alkalies, most of the chlorids and carbonates, some of the nitrates, all the sulphates, essences, and resins. Alcoholic solutions of fixed medicinal substances are called tinctures ; those of volatile prin- ciples, 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 dioxid and water: CalUO-j-SCh =20O j-(-3H... O. 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 tem- peratures, a simple oxidation of the alcoholic radical takes place, with formation of acetic acid 5 j- 04-0-1= (UH30 { o-|_h20, a reaction which is utilized in the manufacture of acetic acid and vinegar. If the oxidation be still further limited, aldehyde is formed: 2C2Ha0-f-02=2C2HJ0-f-2H30. 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 MONOATOM 10 ALCOHOLS. jin atmosphere of alcohol vapor, the products of oxidation are quite numerous: among them are water, ethylene, aldehyde, ace- tylene, carbon monoxid, and acetal. Heated platinum wire in- troduced into vapor of alcohol continues to glow by the heat re- sulting from the oxidation, a fact which has been utilized in the thermocautery. Chlorin and bromin act energetically upon alcohol, producing a number 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. Iodin acts quite slowly in the cold, but old solutions of I in alcohol (tr. iodin) are found to contain HI, ethyl iodid, and other imperfectly studied products. In the presence of an alkali, I acts upon al- cohol to produce iodoform. Potassium and sodium dissolve in alcohol with evolution of H; upon cooling, a white solid crystal- lizes, which is the double oxid of ethyl and the alkali metal, and is known as potassium or sodium ethylate. 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 alkali metals dissolve in alcohol, but react upon it slowly; the solution turns brown and contains an acetate. If alcohol be gently heated with HN03 and nitrate of silver or of mercury, a gray precipitate falls, which is silver or mercury ful- minate. Varieties.—It occurs in different degrees of concentration: ab- solute alcohol is pure alcohol, C2HeO. It is not purchasable, and must be made as required. The so-called absolute alcohol of the shops is rarely stronger than 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 rec- tified spirit used in the arts. Alcohol dilutum (U. S.) —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 H2SOi, 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 iodin, an alcoholic liquid deposits a yellow, crystalline ppt. of iodoform, either immediately or after a time. (3.) If HN03 be added to a liquid containing C2H60, nitrous ether, recognizable by its odor, is given off. If a solution of mercurous nitrate with excess of HNO3 be then added, and the mixture heated, a further evolution of nitrous ether occurs, and a yellow- 244 MANUAL OF CHEMISTRY. 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 H2SO4 diluted with H20 and distilled, the distillate, on treatment with H2S04 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 reactions, taken singly, is characteristic of alcohol. Action on the Economy.—In a concentrated form alcohol exerts a dehydrating action upon animal tissues with which it comes in contact; causing coagulation of the albuminoid constituents. When diluted, ethylic alcohol may be a foot!, 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 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 a valua- ble stimulant. 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 oxidation in the body. Experiments have failed to show that more than a small percentage (TO per cent, in 34 hrs.) of medium doses of alcohol ingested are eliminated by all channels; the remainder, therefore, disappears in the body, as the idea that it can there “ accumulate ” is entirely untenable. 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 expect, in the absence of violent muscular exercise, an increase in temperature, and the appearance in the excreta of some product of oxidation of alcohol: aldehyde, acetic acid, carbon dioxid, or water, while the elimination of nitrogenous excreta, urea, etc., would remain unaltered or be diminished. While there is no doubt that excessive doses of alcohol produce a diminution of body temperature, the experimental evidence concerning the action in this direction of moderate doses is conflicting and in- complete. Of the products of oxidation, aldehyde has not been detected in the excreta, and acetic acid only in the intestinal canal. The elimination of carbonic acid, as such, does not seem to be increased, although positive information upon this point is wanting. If acetic acid be produced, this would form an acetate, which in turn would be oxidized to a carbonate, and eliminated MONOATOMIC ALCOHOLS. 245 as such by the urine. The elimination of water under the influ- ence 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 com- manders 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 prepa- ration 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 classification 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-wines. IV. —Those prepared by the distillation of some fermented sac- charine liquid—ardent spirits. Beer, ale, and porter are aqueous infusions or decoctions of malted grain, fermented and flavored with hops. They contain, therefore, the soluble constituents of the grain employed; dextrin and glucose, produced during the malting; alcohol and carbon dioxid, produced during the fermentation; and the soluble con- stituents of the flavoring material. The alcoholic strength of malt liquors varies from 1.5 to 0 per cent. Weiss beer contains 1.5-1.9 per cent.; lager, 4.1-4.5 per cent.; bock beer, 3.88-5.23 per cent.; London porter, 5.4-6.9 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 phosphates of potassium, sodium, and magnesium pre- dominate 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. 246 MANUAL OF CHEMISTRY. Sodium carbonate is added with the double purpose of neutral- izing an excess of acetic acid and increasing the foam. The most serious adulteration consists in the introduction of bitter princi- ples other than hops, and notably of strychnin, 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 alcohol, the liquid dissolves a por- tion of the coloring matter of the skins. A certain proportion of tannin is also dissolved, whose presence is necessary to prevent stringiness. Sweet wines are produced from must rich in glu- cose, and by arresting the fermentation before that sugar has been completely decomposed. Dry wines are obtained by more complete fermentation of must less rich in glucose. Tartaric acid is the predominating acid in grape-juice, and as the proportion of alcohol increases during fermentation the acid potassium tar- trate is deposited. Most wines of good quality improve in flavor with age, and this improvement is greatly hastened by the process of pasteuring, which consists 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 Ameri- can wines (except some varieties of California wine), Australian, Greek, Hungarian, and Italian wines. The champagnes and some Moselle wines are sparkling, a qual- ity which is communicated to them by bottling them before the fermentation is completed, thus retaining the carbon dioxid, 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 com- municate their fermentation to the contents of the stomach and thus seriously disturb digestion. Of the still wines, the most widely used are the c7arefc,Vinum rubrum (U. S.), or red Bordeaux wines, and the hocks, Vinum album (IT. S.), or white Rhine, Moselle and American wines. The former are of low alcoholic strength, mildly astringent, and contain but a small quantity of nitrogenous 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 nitro- genous material, to which they are indebted for their notoriety MONOATOMIC ALCOHOLS. as developers of 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 Rhine wines and Sauternes than other European wines. Heavy wines are those whose alcoholic strength is greater than 12 per cent., usually 14 to 17 per cent.; 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 substi- tuted 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, fuch- sin, etc. The addition 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 mix- ing of fine grades of wine with those of a poorer quality is exten- sively practised, particularly with sherries, 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- verting white into red wines, or by mixing wines with coloring matters, alcohol, etc., to produce imitations of wines of a differ- ent class, an industry which flourishes extensively in Normandy, at Bingen on the Rhine, and at Hamburg. The wines so pro- duced 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 fermenta- tion, which renders it sour and not only unpalatable, but liab ; to produce colic and diarrhoea with those not hardened to its use. Spirits are alcoholic beverages, prepared by fermentation and distillation. They differ from beers and wines in containing a greater proportion 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 248 MANUAL OF CHEMISTRY. cask; amylic alcohol remaining after imperfect purification; 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 (TJ. S., Br.), obtained by the distilla- tion 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, ac- cording to the quantity of burnt sugar added, and contains about 1.2 per cent, of solid matter. American whiskey, spiritus fru- menti (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 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 distilled 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 Jamaica rum to the colorless St. Croix rum. The former is of sp. gr. 0.914 to 0.920, and contains one per cent, of solid matter. Liqueurs or cordials are spirits sweetened and flavored with veg- etable aromatics, and frequently colored ; anisette is flavored with aniseed; absinthe, with wormwood; curaqoa, with orange-peel; kirschwasser, with cherries, the stones being cracked and the spirits distilled from the bruised fermented fruit; kilmmel, with cummin and caraway seeds; maraschino, with cherries; noyeau, with peach and apricot kernels. Propyl hydrate—Ethyl carhinol—Primary propyl alcohol—CH:i, CH .,CH;OH—00—is produced, along with etliylic 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 tem- peratures ; 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 miscible with water. It has not been put to any use in the arts. Its intoxicating and poisonous actions are greater than those of ethyl alcohol. It exists in small quantity in cider. Butyl alcohols—C iH;)OH—74.—The four butyl alcohols theoret- ically possible are known to exist: Propyl carbinol—Primary normal butyl alcohol—Butyl alcohol of fermentation—CH:t—CH2—CH2—CH2OH—is formed in small quantities during alcoholic fermentation, and may be obtained by repeated fractional distillation from the oily liquid left in the MONO ATOMIC ALCOHOLS. 249 rectification of vinic alcohol. It is a colorless liquid; boils at 114 .7 (238 .5 F.). It is more actively poisonous than ethyl or methyl alcohol. Isopropyl carbinol—Isobutyl alcohol—CH—CH,OH—oc- curs in the fusel oil obtained in the products of fermentation and distillation of beet-root molasses. It is a colorless liquid, sp. gr. 0.8032; boils at 110° (230° F.). Ethyl-methyl carbinol; secondary butyl alcohol— rjir x CHS—CHOH—a liquid which boils at 99° (210°.2 F.). . CH:,\ Trimethyl carbinol; tertiary butyl alcohol, CH,—COH—a crys- CHa/ talline solid, which fuses at 20°-25° (68°-77° F.), and boils at 82° (179°.6 F.). Amylic alcohols—C5H, ,OH—88.—Of the eight amyl alcohols theoretically possible (see p. 239) six have been obtained. The substance usually known as amylic alcohol, potato spirit, fusel oil, alcohol amylicum (Br.), is the primary alcohol —CH2 —CH2OH—with lesser quantities of other alcohols, differing in na- ture and amount with the grain used, and the conditions of the fermentation and distillation. Each kind of “spirit” furnishing and containing a peculiar fusel. In the process of manufacture of ardent spirits the fusel oil ac- cumulates in great part in the still, but much of it distils over, and is more or less completely removed from the product by the process of defuselation. 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 C2H60 and one part strong H2S04. They are not col- ored red or black by ainmoniacal silver nitrate solution. When 150 parts of the spirit, mixed with 1 part potash, dissolved in a little HaO, are evaporated down to 15 parts, and mixed with an equal volume of dilute H2S04, no offensive odor should be given off. While young spirits owe their rough taste and, in great measure, their intoxicating qualities to the presence of fusel oil, it is a pop- ular error that a spirit would be improved by complete removal of all products except ethyl alcohol. The improvement of a spirit by age is due to chemical changes in the small amount of fusel retained in a properly manufactured product, and, were this ab- sent, the spirit would deteriorate rather than improve by age. The individual amylic alcohols have the following characters: Butyl carbinol; normal amylic acohol, CH3—CH2—CH2—CH2— CH2OH—is a colorless liquid, boils at 135° (275° F.). Obtained 250 MANUAL OF CHEMISTRY. from normal butyl alcohol. It yields normal valerianic acid on oxidation. PIT \ Isobutyl carbinol—Amyl alcohol—CH—CH2—CH.OH—is the principal constituent of the fusel oil from grain and potatoes. It is obtained from the last milky products of rectification of alcoholic liquids. These are shaken with H20 to remove ethyl alcohol, the supernatant oily fluid is decanted, dried by contact with fused calcium chlorid, 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 provoca- tive of severe headache. It boils at 132° (269°.G F.) and crystal- lizes at —20° (4° F.); sp. gr. 0.8184 at 15° (5° F.). It mixes with al- cohol and ether, but not with water. It burns difficultly with a pale blue flame. When exposed to air it oxidizes very slowly; quite rapidly, how- ever, in contact with platinum-black, forming valerianic acid. The same acid, along with other substances, is produced by the action of the more powerful oxidants upon amyl alcohol. Chlorin attacks it energetically, forming amyl chlorid, HC1, and other chlorinated derivatives. Sulphuric acid dissolves in amyl alcohol, with formation of amyl-sulpliuric acid, S04(C6Hn)H, correspond- ing to ethyl-sulphuric acid. It also forms similar acids with phos- phoric, oxalic, citric, and tartaric acids. Its ethers, when dis- solved in ethyl alcohol, have the taste and odor of various fruits, and are used in the prepax*ation of artificial fruit-essences. Amyl alcohol is also used in analysis as a solvent, particularly for cer- tain alkaloids, and in pharmacy for the artificial production of valerianic acid and the valerianates. Diethyl carbinol—ojj —CH2 —*s Pro(^ by the action of a mixture of zinc and ethyl iodid on ethyl formiate, with the subsequent addition of H20. It is a liquid which boils at 116°.5 (241°.7 F.). Methyl-propyl-carbinol — qjj CH. — CH2 CITOH—a liquid, boiling at 118°.5 (245°.3 F.), obtained by the hydrogenation of methylpropylic acetone. Methyl-isopropyl-carbinol—Amylene hydrate— (CHj )2 —^CHOH—obtained by the hydrogenation of methyl- isopropylic acetone; or by the action of hydriodic acid upon amy- lene, and the action of moist silver oxid upon the product so ob- tained. It is a colorless liquid, sp. gr. 0.829 at0° (32° F.), having a pungent, ethereal odor; boils at 108° (226°.4 F.); soluble in H2G and in alcohol. Has been used as a hypnotic. SIMPLE ETHERS Ethyl-dimethyl-carbinol—'Tertiary arnylic alcohol— CHA CHa—CH3—COH—is a liquid which solidifies at —12° (10°.4 F.)and CH3/ boils at 102°.5 (216°.5 F.); formed by the action of zinc methyl upon propionyl chlorid, or by decomposition of tertiary sulphamy- lic acid by boiling HjO. It is a colorless liquid; sp. gr. 0.828 at 0° (32° F.), crystallizes at —30° (—22" F.), boils at about 100’ (212° F.). The nitrite of this alcohol has been used as a substitute for amyl nitrite. Cetyl hydrate—Cetylic alcohol—Ethal— C,sH3aOH—242—is ob- tained by the saponification of spermaceti (its palmitic ether). It is a white, crystalline solid; fusible at 49° (120°.2 F.); insoluble in H20; soluble in alcohol and ether; tasteless and odorless. Ceryl hydrate—CJTH;>r)OH—396—and Myricyl hydrate—C:i HM OH—438—are obtained as white, crystalline solids: the former from China wax; the latter from beeswax, by saponification. SIMPLE ETHERS. The term ether was originally applied to any volatile liquid obtained by the action of an acid upon an alcohol. The simple ethers are the oxids of the alcoholic radicals. They bear the same relation to the alcohols that the oxids of the basyl- ous elements bear to their hydrates: Oxids of Alcoholic Radicals of the Series CnH2n + i. C,H») n c2h5 j u Kl0 K ) u c,h5>0 Klo H f u Ethyl oxid (ethylic ether). Potassium oxid. 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 methyl-ethyl oxid, 3 ( O, they are called mixed ethers. qtx Methyl oxid—qjj3 ' O—46—isomeric with ethyl alcohol, is ob- tained by the action of H3SCh and boric acid upon methyl al- cohol, or by the action of silver oxid on methyl iodid. It is a colorless gas; has an ethereal odor; burns with a pale flame; liquefies at — 36c (—32°.8 F.); and boils at —21° (—5°.8 F.); is solu- ble in H20, H3SO4 and ethyl alcohol. Ethyl oxid—Ethylic ether—Ether—Sulphuric ether—2Ether fortior (TJ. S.)—iEther purus (Br.)—£'5 } 0—74. ) Preparation.—A mixture is made of 5 pts. of alcohol, 90$, and 9 MANUAL OF CHEMISTRY. pts. of concentrated H2S04, in a vessel surrounded by cold H20. This mixture is introduced into a retort, over which is a vessel from which a slow stream of alcohol is made to enter the retort. Heat is applied, and the addition of alcohol and the heat are so regulated that the temperature does not rise above 140° (284° F.). The retort is connected with a well-cooled condenser, and the process continued until the temperature in the retort rises above the point indicated. It is important that the tube by which the alcohol is introduced be drawn out to a small opening, and dip well down below the surface of the liquid. The distillate thus obtained contains ether, alcohol, water, and gases resulting from the decomposition of the alcohol and H2S04, notably S02. It is subjected to a first purification bv shaking with H20 containing potash or lime, decanting the supernatant ether and redistilling. The product of this process is “washed ether,” or aether (U. S.). It is still contaminated with water arid alcohol, and when desired pure, as for producing anaesthesia and for processes of analysis, it is subjected to a second purification. It is again shaken with H20, decanted after separation, shaken with recently fused cal- cium chlorid and newly burnt lime, with which it is left in con- tact 24 hours, and from which it is then distilled. It was known at an early day that a small quantity of H2S04 is capable of converting a large quantity of alcohol into ether, and that at the end of the process the H2S04 remains in the retort unaltered, except by secondary reactions. A metaphysical ex- planation of the process was found in the assertion that the acid acted by its mere presence, by catalysis, as it was said. In other words, it acts because it acts, a very ready but a very feminine method of explaining what is not understood, which is still in- voked by some authors as a covering for our ignorance of the rationale of certain chemico-physiological phenomena. It was only in 1850 that Alex. Williamson, by a series of ingenious expe- riments, determined the true nature of the process. In the con- version of alcohol into ether, an intermediate substance, sulpho- vinic acid, is alternately formed at the expense of the alcohol, and destroyed with formation of ether and regeneration of H2S04. At first H2S04 and alcohol act upon each other, molecule for molecule, to form H20 and sulpliovinic acid: 2 jq5 j- O-f-^y2 | 02 =T> [0 4- C2H5 - Oa. The new acid as soon as formed reacts with H J H j a second molecule of alcohol, with regeneration of H2S04 and for- mation of ether: CJH j- 02+C'2lJ| |- 0=Sgj J- | O. Theoretically, therefore, a given quantity of H2S04 could con- SIMPLE ETHERS. 253 vert an unlimited amount of alcohol into ether. Such would also be the case in practice, were it not that the acid gradually be- comes too dilute, by admixture with the HUO formed during the reaction, and at the same time is decomposed by secondary reac- tions, into which it enters with impurities in the alcohol; causes which in practice limit the amount of ether produced to about four to five times the bulk of acid used. Ether is a colorless, limpid, mobile, highly refracting liquid; it has a sharp, burning taste, and a peculiar, tenacious odor, char- acterized as ethereal. Sp. gr. 0.723 at 12°.5 (54°.5 F.); it boils at 34°.5 (94°. 1 F.), and crystallizes at —31° (—23°.8 F.). Its tension of vapor is very great, especially at high temperatures; it should, therefore, be stored in strong bottles, and should be kept in situ- ations protected from elevations of temperature. It is exceedingly volatile, and, when allowed to evaporate freely, absorbs a great amount of heat, of which property advantage is taken to produce local anaesthesia, the part being benumbed by the cold produced by the rapid evaporation of ether sprayed upon the surface. Water dissolves one-ninth its weight of ether. Ethylic andme- thylic alcohols are miscible with it in all proportions. Ether is an excellent solvent of many substances not soluble in water and alcohol, while, on the other hand, it does not dissolve many sub- stances soluble in those fluids The resins and fats are readily soluble in ether; the salts of the alkaloids and many vegetable coloring matters are soluble in alcohol and water, but insoluble in ether, while the free alkaloids are for the most part soluble in ether, but insoluble, or very sparingly soluble, in water. Ether, whether in the form of vapor or of liquid, is highly in- flammable; and burns with a luminous flame. The vapor forms with air a violently explosive mixture. It is denser than air, through which it falls and diffuses itself to a great distance; great caution is therefore required in handling ether in a locality in which there is a light or fire, especially if the fire be near the floor. Pure ether is neutral in reaction, but, on exposure to air or O, especially in the light, it becomes acid from the formation of a small quantity of acetic acid. HUSCh mixes with ether, with ele- vation of temperature, and formation of sulphovinic acid. Sul- phuric anhydrid forms ethyl sulphate. HN03, aided by heat, oxidizes ether to carbon dioxid and acetic and oxalic acids. Ether, saturated with HC1 and distilled, yields ethyl chlorid. Cl, in the presence of H20, oxidizes ether, with formation of aldehyde, acetic acid, and chloral. In the absence of H20, however, a series of products of substitution are produced, in which 2, 4 and 10 atoms of H are replaced by a corresponding number of atoms of Cl. These substances in turn, by substitution of alcoholic radicals, or 254 MANUAL OF CHEMISTRY. of atoms of elements, for atoms of Cl, give rise to other deriva- tives. Action on the Economy.—Ether is largely used in medicine for producing anaesthesia, either locally by diminution of tempera- ture due to its rapid evaporation, or generally by inhalation. When taken in overdose it causes death, although it is by no means as liable to give rise to fatal accidents as is chloroform. Pa- tients suffering from an overdose may, in the vast majority of cases, be resuscitated by artificial respiration and the induced current, one pole to be applied to the nape of the neck, and the other carried across the body just below the anterior attachments of the diaphragm. In cases of death from ether the odor is generally well marked in the clothing and surroundings, and especially on opening the thoracic cavity. In the analysis it is sought for in the blood and lungs at the same time as chloroform (q.v.). MONOBASIC ACIDS. As the higher terms of this series are obtained from the fats, and the lower terms are volatile liquids, these acids are some- times designated as the volatile fatty acids. Although formed in a variety of ways, these acids may be con- sidered as being derived from the primary monoatomic alcohols, by the substitution of 0 for H2 in the group CH2OH : Series CwH2”02. ch3—ch2—ch2—ch2—ch2,oh CH3—CH2—CH„—CH2—CO,OH Normal amylic alcohol. Normal valerianic acid. Considered typically, the substitution of O for H2 occurs in the radical: * 11 j- O— CsHsO j an(j communicates to the radical electro-negative or acid qualities. Formic acid—HCO.OH—46—occurs in the acid secretion of red ants, in the stinging hairs of certain insects, in the blood, urine, bile, perspiration, and muscular fluid of man, in the stinging- nettle, and in the leaves of trees of the pine family. It is pro- duced in a number of reactions; by the oxidation of many or- ganic substances: sugar, starch, fibrin, gelatin, albumin, etc.; by the action of potash upon chloroform and kindred bodies; by the action of mineral acids in hydrocyanic acid; during the fer- mentation of diabetic urine; by the direct union of carbon mon- MONOBASIC ACIDS. oxid and water; by the decomposition of oxalic acid under the influence of glycerin at about 100" (212° F.). It is a colorless liquid, having an acid taste and a penetrating odor; it acts as a vesicant; it boils at 100° (2123 F.), and, when pure, crystallizes at 0° (32° F.). It is miscible with HaO in all proportions. The mineral acids decompose it into HaO and carbon monoxid. Oxidizing agents convert it into HaO and carbon dioxid. Alka- line hydrates decompose it with formation of a carbonate and liberation of H. It acts as a reducing agent with the salts of the noble metals. Acetic acid—Acetyl hydrate—Hydrogen acetate—Pyroligneous acid—Acidum aceticum (U. S.; Br.)—CHj.COOH—60. It is formed—(1.) By the oxidation of alcohol: CH3,CHa0H+03=CH3,C00H+H,0 (2.) By the dry distillation of wood. (3.) By the decomposition of natural acetates by mineral acids. (4.) By the action of potash in fusion on sugar, starch, oxalic, tartaric, citric acids, etc. (5.) By the decomposition of gelatin, fibrin, casein, etc., by H2SO4 and manganese dioxid. (6.) By the action of carbon dioxid upon sodium methyl: C02+NaCH3=CiH302Na; and decomposition of the sodium ace- tate so produced. The acetic acid used in the arts and in pharmacy is prepared by the destructive distillation of wood. The products of the dis- tillation, which vary with the nature of the wood used, are numerous. Charcoal remains in the retort, while the distilled product consists of an acid, watery liquid; a tarry material; and gaseous products. The gases are carbon dioxid, carbon monoxid, and hydrocarbons. The tar is a mixture of empyreumatic oils, hydrocarbons, phenol, oxyphenol, acetic acid, ammonium ace- tate, etc. The acid water is very complex, and contains, besides acetic acid, formic, propionic, butyric, valerianic, and oxyphenic acids, acetone, naphthalene, benzene, toluene, cumene, creasote, methyl alcohol, and methyl acetate, etc. Partially freed from tar by de- cantation, it still contains about 20 per cent, of tarry and oily material, and about 4 per cent, of acetic acid; this is the crude pyroligneous acid of commerce. The crude product is subjected to a first purification by distil- lation ; the first portions are collected separately and yield methyl alcohol (q.v.); the remainder of the distillate is the distilled pyroligneous/ acid, used to a limited extent as an antiseptic, but principally for the manufacture of acetic acid and the acetates. 256 MANUAL OK CHEMISTRY. It can only be freed from the impurities which it still contains by chemical means. To this end slacked lime and chalk are added, at a gentle heat, to neutralization; the liquid is boiled and allowed to settle twenty-four hours; the clear liquid, which is a solution of calcium acetate, is decanted and evaporated; the calcium salt is converted into sodium acetate, which is then purified by cal- cination at a temperature below 330° (626° F.), dissolved, filtered, and recrystallized; the salt is then decomposed by a proper quan- tity of H2SO4, and the liberated acetic acid separated by distilla- tion. The i>roduct so obtained is a solution of acetic acid in water, containing 30 per cent, of true acetic acid, and being of sp. gr. 1.047, U. S. (the acid of the Br. Ph. is weaker—33 per cent. C2H402, and sp. gr. 1.044). Pure acetic acid, known as glacial acetic acid, acidum aceticum glaciale (U. S.), is obtained by decomposition of a pure dry ace- tate by heat. Acetic acid is a colorless liquid. Below 17° (62 .6 F.), when pure, it is a crystalline solid. It boils at 119° (246°.2 F.); sp. gr. 1.0801 at 0° (32° F.); its odor is penetrating and acid; in contact with the skin it destroys the epidermis and causes vesication; it mixes with HaO in all proportions, the mixtures being less in vol- ume than the sum of the volumes of the constituents. The sp. gr. of the mixtures gradually increase up to that containing 23 per cent, of H20, after which they again diminish, and all the mixtures containing more than 43 per cent, of acid are of higher sp. gr. than the acid itself. Vapor of acetic acid burns with a pale blue flame; and is de- composed at a red heat. It only decomposes calcic carbonate in the presence of H20. Hot H2S04 decomposes and blackens it, S02 and C02 being given off. Under ordinary circumstances Cl acts upon it slovdy, more actively under the influence of sunlight, to produce monochloracetic acid, CH2C1C0,0H ; dichloracetic acid, CHCl2CO,OH; and trichloracetic acid, CCl;,CO,OH. The last named is an odorless, acid, strongly vesicant, crystalline solid; fuses at 46° (114°.8 F.) and boils at 195°-200° (383°-392° F.). Analytical Characters.—(1.) Warmed with H2S04 it blackens. (2.) With silver nitrate a white crystalline ppt., partly dissolved by heat; no reduction of Ag on boiling. (3.) Heated with H2S04 and C2H60, acetic ether, recognizable by its odor, is given off. (4.) When an acetate is calcined with a small quantity of As2Oa the foul odor of cacodyl oxid is developed. (5.) Neutral solution of ferric clilorid produces in neutral solutions of acetates a deep red color, which turns yellow on addition of free acid. Vinegar is an acid liquid owing its acidity to acetic acid, and holding certain fixed and volatile substances in solution. It is MONOBASIC ACIDS. obtained from some liquid containing 10 per cent, or less of al- cohol, which is converted into acetic acid by the transferring of atmospheric oxygen to the alcohol during the process of nutri- tion of a peculiar vegetable ferment, known as mycoderma aceti, or, popularly, as mother of vinegar. Vinegar is now manufac- tured principally by one of two processes—the German method, and that of Pasteur. In the former, the alcoholic fluid, which must also contain albuminous matter, is allowed to trickle slowly through barrels containing beeeh-wood shavings, supported by a perforated false bottom. By a suitable arrangement of holes and tubes, an ascending current of air is made to pass through the barrel. The acetic ferment clings to the shavings, and under its influence acetiftcation takes place rapidly, owing to the large sur- face exposed to the air. In Pasteur's process, the ferment is sown upon the surface of the alcoholic liquid, contained in large, shal- low, covered vats, from which the vinegar is drawn off after acet- ifieation has been completed; the mother is collected, washed, and used in a subsequent operation. The liquids from which vinegar is made are wine, cider, and beer, to which dilute alcohol is frequently added; the most es- teemed being that obtained from white wine. 1 Vine vinegar has a pleasant, acid taste and odor; it consists of water, acetic acid (about 5 per cent.), potassium bitartrate, alcohol, acetic ether, glucose, malic acid, mineral salts present in wine, a fermentesci- ble, nitrogenized substance, coloring matter, etc. Sp. 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 potassium bitartrate, contain less acetic acid, and have not the aromatic odor of wine vinegar. Cider vinegar is of sp. gr. 1.020; is yellowish, has an odor of apples, and yields 1.5 per cent, of extract on evaporation. Beer vinegar is of sp. gr. 1.082; 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 produces 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 vinegar, 8.5 parts; and of beer vinegar, 2.5 parts of carbonate. Pyrolig- neous acid may be detected by the creasote-like odor and taste. Pepper, capsicum, 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 258 MANTAL OF CHEMISTRY. sodium carbonate. Copper, zinc, lead, and tin frequently occur in vinegar which has been in contact with those elements, either during the process of manufacture or subsequently. Distilled vinegar is prepared by distilling vinegar in glass ves- sels; it contains none of the fixed ingredients of vinegar, but its volatile constituents (acetic acid, water, alcohol, acetic ether, odor- ous 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 50° (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 instances 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—CH;j.CH,,—COOH—is formed by the action of caustic potassa upon sugar, starch, gum, and ethyl cyanid; dur- ing 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 cyanid with potash until the odor of the ether has disappeared; the acid is then liberated from its potassium compound by H2S04 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 crystallizable. Butyric acid—Propyl-formic acid—CH:i—CH,—CH2—COOH—has been found in the milk, perspiration, muscular fluid, the juices of the spleen and of other glands, the urine, contents of the stomach and large intestine, faeces, and guano; in certain fruits, in yeast, in the products of decomposition of many vegetable 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 H2SG4 and manganese dioxid, aided by heat, upon cheese, starch, gelatin, etc.; during the com- bustion of tobacco (as ammonium butyrate); by the action of HN03 upon oleic acid; during the putrefaction of fibrin and other albuminoids; during a peculiar fermentation of glucose and starchy material in the presence of casein or gluten. This fer- mentation, known as the butyric, takes place in two stages; at first the glucose is converted into lactic acid: C«H, 2 O e=2 (C 3 H r, O 3); and this in turn is decomposed into butyric acid, carbon dioxid, and hydrogen: 2C3H603 = C4Hr02-f2C02-j-2H!i. MONOBASIC ACIDS. 259 Butyric acid is obtained from the animal charcoal which has been used in the purification of glycerin, in which it exists as cal- cium butyrate. It is also formed by subjecting to fermentation a mixture composed of glucose, water, chalk, and cheese or gluten. The calcium butyrate is decomposed by H2SCh, and the butyric acid separated by distillation. Butyric acid is a colorless, mobile liquid, having a disagreeable, persistent odor of rancid butter, and a sharp, acid taste; soluble in water, alcohol, ether, and methyl alcohol; boils at 184° (327 .2 F.), distilling unchanged; solidifies in a mixture of solid carbon dioxid and ether; sp. gr. 0.974 at 15° (59° F.); a good solvent of fats. It is not acted upon by H3SCh 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 products of substitution with butyric acid. It readily forms ethers and salts. Butyric acid is formed in the intestine, by the process of fermen- tation 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. pTT Isobutyric acid—Isopropyl-formic acid—qjj ‘ CH—COOH—boils at 152° (305°.0 F.), has been found in human faeces. It corresponds to isobutyl alcohol, from which it is produced by oxidation. Valerianic acids—C,H;,CO,OH—102.—Corresponding to the four primary amylic alcohols, there are four possible amylic or valeri- anic acids, of which three, I., II., and IV., are known. I. oh3—ch2—ch3—ch3—CO,oh. II. —CH^—C°,°H- II!. CH3-gg;>CH-CO,OH CH3\ iv ch3—c—CO,oh. ch3/ 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’ (865° F.), and has an odor resembling that of butyric acid. II. Ordinary valerianic acid—Delphinic acid—Phocenic acid— Isovaleric acid—Isopropyl acetic acid—Isobutylformic acid— Acidum valerianicum (Br.).—This acid exists in the oil of the por- poise, and in valerian root and in angelica root. It is formed during putrid fermentation or oxidation of albuminoid sub- stances. It occurs in the urine and faeces in typhus, variola, and 260 MANUAL OF CHEMISTRY. acute atrophy of the liver. It is also formed in a variety of chem- ical 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 H2SCb, adding when cold, a solution of potassium dichromate, and dis- tilling after the reaction has become moderated: the distillate is neutralized with sodium carbonate; and the acid is obtained from the sodium valerianate so produced, by decomposition by H2SO4 and rectification. The ordinary valerianic acid is an oily, colorless liquid, having a penetrating 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. IV. Trimethyl acetic acid—Pivalic acid—is a crystalline solid, which fuses at 35°.5 (96° F.) and boils at 163°.7 (326°.7 F.); spar- ingly soluble inH20; obtained by the action of cyanid of mer- cury upon tertiary butyl iodid. Caproic acids—Hexylic acids—C5Hn,COOH—116.—There proba- bly exist quite a number of isomeres having the composition in- dicated above, some of which have been prepared from butter, cocoa-oil, and cheese, and by decomposition of amyl cyanid, 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. CEnanthylic acid—Heptylic acid—Cf,Hi3,COOH—130—exists in spirits distilled from rice and maize, and is formed by the action of HN03 on fatty substances, especially castor-oil. It is a color- less oil; sp. gr. 0.9167; boils at 212° (413°.6 F.). Caprylic acid—Octylic acid— CfH, 5. COOH—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 H20. Pelargonic acid—Nonylic acid—Cf H17,COOH—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 HN03 on oil of rue. Capric acid—Decylic acid—CH^.COOH—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 acid—CnH2:i,COOH—200—is a solid, fusible at 43°.5 (110°.3 F.), obtained from laurel berries, cocoa-but- ter, and other vegetable fats. MONOBASIC ACIDS. 261 Myristic acid—Cl3HJ7,COOH—228.—A crystalline solid, fusible at 54° (129 .2 F.); existing in many vegetable oils, cow's butter, and spermaceti. Palmitic acid—Ethalic acid—C10H3i,COOH—256—exists in palm- oil, in combination when the oil is fresh, and free when the oil is old; it also 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—C, r,H33,COOH—270—formerly supposed to exist as a glyeerid 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 cyanid, as a white, crystalline body; fusible at 59’.9 (140' F.). Stearic acid—CieHas,COOH—284—exists as a glyeerid 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 In HC1; the stearic acid which separates is washed and reerystallized from alcohol. The process is repeated until the product fuses at 70° (158° F.). Stearic acid is formed from oleic acid (q.v.) by the action of iodin under pressure at 270°-280° (518°-536° 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 solu- ble in H-iO; those of Ca, Ba, and Pb are insoluble. Stearic and palmitic acids exist free in the intestine during the digestion of fats, a portion of which is decomposed by the action of the pancreatic secretion into fatty acids and glycerin. The same decomposition also occurs in the presence of putrefying albuminoid substances. Arachic acid—C19H39.COOH—312—exists as a glyeerid 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.). 262 MANUAL OF CHEMISTRY. COMPOUND ETHERS. As the alcohols resemble the mineral bases, and the organic acids resemble those of mineral origin, so the compound ethers are similar in constitution 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 decomposition of an acid and a mineral base, the radical playing the part of an atom of corresponding valence : K ? © i (NOa) ) q _ H ) o i (NOa) ) q Hfu + HfU “ HfU + K'fU Potassium hydrate. (C- + = H f 0 - Nitric acid. Water. Potassium nitrate. Ethyl hydrate (alcohol). Nitric acid. Water. Ethyl nitrate (nitric ether). Therefore the compound ethers are acids whose hydrogen has been partially or completely displaced by a hydrocarbon radical or radicals. Some of the compound ethers still contain a portion of the acid hydrogen which, being replaceable by another radical or by a metal, communicates acid qualities to the substance, which is at the same time a compound ether and a true acid. The compound ethers are produced : 1.) By the action of the acid upon the alcohol: Sulphuric acid. h2so4 + c2h5,oh = c2h6,hso4 + h2o Ethyl hydrate. Ethylsulphuric acid. Water. H2S04 + 2C2H5,OH = (C2H5)a,S04 + 2H20 Sulphuric acid. 2.) By the action of the corresponding haloid ethers upon the silver salt of the acid : Ethyl hydrate. Ethyl sulphate. Water. Silver nitrate. AgNOa + C2H5I = Agl + C2H6,N03 Ethyl iodid. Silver iodid. Ethyl nitrate. 3.) By the action of the chlorids of the acid radicals upon the sodium derivatives of the alcohols, and in some instances upon the alcohols themselves: Acetyl chlorid. C2H302C1 + C2HBNa = NaCl + (C2HB)C2H302. Sodium ethylate. Sodium chlorid. Ethyl acetate. All compound ethers are decomposed into acid and alcohol by the action of water at high temperatures, or of caustic potash or soda: Ethyl nitrate. (C2H5)N03 + KHO = KNOa + C2H5HO Potassium hydrate. Potassium nitrate. Ethyl hydrate. COMPOUND ETHERS. 263 As this decomposition is analagous to that utilized in the man- ufacture of soap (q. v.), it is known as saponification, and when- ever an ether is so decomposed it is said to be saponified. 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 de- tonates at 150° (302° F.). Prepared by the action of potassium nitrate and hUSCh on methyl alcohol. Methyl nitrite—j- O—61—obtained by heating methyl alco- hol with HN03 and Cu. Below —12° (10°.4 F.) it is a yellowish liquid ; above that temperature a gas. Ethyl nitrate—Nitric ether—j- 0—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. Pre- pared by distilling a mixture of HN03 and C2HbO in the pres- ence of urea. Ethyl nitrite—Nitrous ether— j- 0—75—is best prepared by directing the nitrous fumes, produced by the action of starch on HN03 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 in- flammable vapor ; very sparingly soluble in H20 ; readily soluble in alcohol and ether. Warm H20 decomposes itintoC2H60, HN03 and NO. Alkalies decompose it into malate and nitrate of the alkaline element. It is energetically attacked by H2SO.t, H2S and the alkaline sul- pliids. It is liable to spontaneous decomposition, especially in the presence of H20. Its vapor rapidly produces anesthesia; it is, however, used only in alcoholic solution : Spiritus setheris nitrosi (XT. 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 H20, a change which renders it un- fit for use in many of the prescriptions in which it is frequently used, especially in that with potassium iodid, from which it lib- erates iodin. The presence of free acid may be detected by effervescence when the spirit is shaken with hydrosodic carbon- ate. Its acidity may be corrected by shaking with potassium carbonate, and decanting, provided it does not contain H20. (See Nitro-paraffins.) 264 MANUAL OF CHEMISTRY. Ethyl sulphates.—These are two in number : (CiH;i)HSOJ = Ethyl-sulphuric or sulphovinic acid and (C,H*),S04—Ethyl sulphate—Sulphuric ether. SO, ) Ethyl-sulphuric Acid—(C,H6) ■- O,—126—is formed as an inter- H ) mediate 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 Avater and alcohol in all propor- tions, insoluble in ether. It decomposes slowly at ordinary temperatures, more rapidly AA’hen heated. When heated alone or with alcohol, it yields ether and H2SO4. When heated with H20, it yields alcohol and H,S04. It forms crystalline salts, known as sulphovmates, one of Avhicli, sodium sulphovinate, (C,H5)NaS04. has been used in medicine. It is a white, deliquescent solid either crystalline with 1 Aq, or granular and anhydrous ; soluble in H,0. Its solution should give no precipitate \\rith barium chlorid. Ethyl Sulphate.—(C,Hs),SO 4—154—the true sulphuric ether, is obtained by passing Arapor of S03 into pure ethylic ether, thor- oughly cooled. It is a colorless, oily liquid ; has a sharp, burningtaste, and the odor of peppermint; sp. gr. 1.120 ; it cannot be distilled without decomposition ; in contact with HO, it is decomposed with for- mation of sulphovinic acid. By the action of an excess of H2SO4 upon alcohol ; by the dry distillation of the sulplioATinates ; and in the last stages of manu- facture of ether, a yelloAvisli, 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 aethereum (U. S.). It seems to be a mixture of ethyl sulphate with hydrocarbons of the series Cn,H,?i. On contact with H20 or an alkaline solution, it is decomposed, sulphovinic acid is formed, and there separates a colorless 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, Ci8H3,. It is sometimes called etherin or etherol. Sulphurous and Hyposulphurous ethers.—These compounds have recently assumed medical interest from their relationship to mercaptan, sulplional and a number of aromatic derivatives used as medicines. There exist two isomeric sulphurous acids (see p. 97), both of which yield neutral ethers, but only one of which, the unsym- metrical, forms acid ethers. These acid ethers are known as sulphonic acids. (See Aromatic sulphonic acids, mer- captan, sulphones, sulplional.) Diethyl sulphite—(C..H5),SO s—is produced by the action of COMPOUND ETJIERS. 265 tliionyl chlorid on absolute alcohol : SOCla+2C3H6HO = S03 (CoH6)a+2HCl. It is a colorless liquid, having a powerful odor : sp. gr. 1.085, boils at 161° (321°.8 F.). HaO decomposes it into alcohol and sulphurous acid. Ethyl sulphonic acid.—SO , 4—is formed by the action of ethyl iodid on potassium sulphite : CaH6I+S03Ka=CaH6, SOaOK + KI. It forms salts and ethers. Sulphinic acids—are the acid ethers of hyposulphurous acid / H and are analagous to the sulphonic acids. Ethyl acetate—Acetic ether—ASther aceticus (TJ. S.) j- 0— 88—is obtained by distilling a mixture of sodium acetate, alco- hol and H 3SO4; or by passing carbon dioxid through an alcoholic solution of potassium acetate. It is a colorless liquid, has an agreeable, ethereal odor ; boils at 74° (165c.2 F.); sp. gr. 0.89 at 15° (59° F.); soluble in 6 pts. wa- ter, and in all proportions in methyl and ethyl alcohols and in ether; a good solvent of essences, resins, cantharidin, morpliin, gun-cotton, and in general, of substances soluble in ether ; burns with a yellowish-white flame. Chlorin acts energetically upon it, producing products of substitution, varying according to the intensity of the light from CtH6ClaOa to C4CLO2. Amyl nitrate | 0—133—obtained by distilling a mix- ture of HNOs and amylie 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°.4F.) with partial decomposition. Amyl nitrite—Amyl nitris (TJ. S.)—q 0—117 — prepared by directing the nitrous fumes, evolved by the action of HN03 upon starch, into amyl alcohol contained in a retort heated over a water-bath ; purifying the distillate by washing with an alka- line 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.); insolu- ble in water ; soluble in alcohol in all proportions ; vapor orange- colored. Alcoholic solution of potash decomposes it slowly, with formation of potassium nitrite and oxids of ethyl and amyl. When dropped upon fused potash, it ignites and yields potas- sium valerianate. Amyl nitrite is frequently impure ; its boiling-point should not vary more than two or three degrees from that given above. Cetyl palmitate — Cetin — | ®—480—is the chief con- stituent of spermaceti = cetaceum (TJ. S., Br.). This is the con- crete portion, obtained by expression and crystallization from 266 MANUAL OF CHEMISTRY. alcohol, of the oil contained in the cranial sinuses of the sperm whale. It forms white, crystalline 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 cetin, it contains ethers not only of palmitic, but also of stearic, myristic, and laurostearic acids ; and of the alcohols: lethal, C12H260; methal, C14H30O; ethal, Ci6H340 ; and stethal, Cit.H3t.O. Melissyl palmitate—Melissin—j- 0—676.—Beeswax con- sists mainly of two substances ; cerotic acid, C24H530,0H, 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°-6B° (143°.6-145°.4 F.) ; after bleaching, 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, C27H33O2(02tH56). ALDEHYDES. Series CwH2nO. It will be remembered that the monobasic acids are obtained from the alcohols by oxidation of the radical: (CsH5) ) n H f u (C.HsO)' ) n Hfu These oxidized radicals are capable of forming compounds similar in constitution to those of the non-oxidized radicals. There are clilorids, bromids, and iodids ; their hydrates are the acids, (C2H30) l q — acetjc acid ; their oxids are known as anhydrids, } O=acetic anliydrid; and their liydrids are the aldehydes (C3H3O0 | _ 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 constitution may be thus graphically indicated : Ethyl alcohol. Acetic acid. COH CH, CH3 COH ch3 Acetic aldehyde. Propionic aldehyde. ALDEHYDES. 267 They are capable, by fixing H2, of regenerating the alcohol; and, by fixing O, of forming the corresponding acid : COH I ch3 ch2oh CHj CO,OH I ch3 Acetic aldehyde Ethylic alcohol. Acetic acid The aldehydes combine with the acid sulphites of the alkali met- als to form crystalline compounds. They combine with ammonia to form aldehyde-ammonias: CH3CHO+NH3 = CH3 • They are converted by Cl and Br into the chlorids or bromids of the acid radicals. The aldehydes are formed : 1. By the limited oxidation of the corresponding alcohol : CH3CH20H + 0 = CH3C0H + H20. 2. By the action of nascent H upon the chlorids or anhydrids of the corresponding acids : CH3COCI+H3 = CH3,COH + HCl or (CH3C0)20-l-2H2 = 2CH3C0H + H20. 3. By the distillation of a mixture of calcium formiate and the Ca salt of the corresponding acid : (HCOOLCa-KCHsCOOhCa = 2C03Ca-t-2CH3.C0H. Formaldehyde—Formyl hydrid—H,COH—30—is formed when air charged with vapor of methylic alcohol is passed over an in- candescent platinum wire. It is also produced by the dry distil- lation of calcium formiate : (HCOO)2Ca = CaC03-i-HC0H. It has not been obtained pure, but is known in solution in methyl al- cohol. Corresponding to this aldehyde is a product of condensation. Paraformaldehyde, or Trioxymethane (H,COH)3, which is ob- tained, as a crystalline substance, fusing at 152° (305°.6 F.), in- soluble in H20, alcohol and ether, by distilling glycollic acid with H.2SO4, or by the action of silver oxalate or oxid on methene iodid r 3CH2I2+3COOAg2 = (HCOH)3+6AgI + 3CO. Acetaldehyde—Acetic aldehyde—Acetyl hydrid—CH3COH—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 mix- ture of HsS04, 6 pts.; H20, 4 pts.; alcohol, 4 pts.; and powdered manganese dioxid, 6 pts. The product is redistilled from calcium chlorid below 50° (122° F.). 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 acetylid, C.H3O, NH„ which are washed with ether, dried, and decom- posed in a distilling apparatus, over the water-bath, with the proper quantity of dilute H2S04 ; the distillate is finally dried over calcium chlorid and rectified below 35° (95° F.). MANUAL OF CHEMISTRY. Aldehyde is a colorless, mobile liquid ; has a strong, suffocating odor; sp. gr. 0.790 at 18° (64°.4 F.) ; boils at 21° (69 .8 F.) ; soluble in all proportions 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° F.), it is decomposed into water and crotonic alde- hyde. In the presence of nascent H, aldehyde takes up H2 and re- generates alcohol. Cl converts it into acetyl chlorid, C2H30, Cl, and other products. Oxidizing agents quickly convert it into acetic acid. At the ordinary temperature H2S04 ; HC1; and S02 convert it into a solid substance called paraldehyde, C6H1203 (?), which fuses at 10°.5 (50°.9 F.); boils at 124° (255°.2 F.), and is more soluble in cold than in warm water. When heated with potas- sium 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 HoS, a solid, crystalline base, thialdin, C6Hi3NS2, 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 conditions which cause it to adhere strongly to glass. Vapor of aldehyde, when inhaled in a concentrated form, pro- duces asphyxia, 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 produets of the distillation of spirits of inferior quality owe in a great measure their rapid, deleterious action. Trichloraldehyde — Trichloracetyl hydrid—Chloral—CC1.,C0H —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; applying heat toward the end of the re- action, 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 H2S04 and again allowed to separate into two layers ; the upper is decanted ; again mixed with H2S04, from which it is distilled ; the distillate is treated with quicklime, from which it is again distilled, that portion which passes over between 94° and 99° (201°.2-210°.2 F.) being col- lected. It sometimes happens that chloral in contact with II2S04 is converted into a modification, insoluble in H20, known as metachloral; when this occurs it is washed with H20, 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 pene- ALDEHYDES. trating 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, 1, 8 and P. Its vapor is highly irritat- ing. It distils without alteration. Although chloral has not been obtained by the direct substitu- tion of Cl for H in aldehyde, its reactions show it to be an alde- hyde. It forms crystalline compounds with the bisulphites ; it reduces solutions of silver nitrate in the presence of NH3 ; NH3 and H2S form with it a compound similar to thialdin; 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 C2HC130,H20, and its constitution, as well as that of chloral itself, is indicated by the formula): ch3 I CHO CCh CHO CC13 I CH(OH)2 Aldehyde. Trichloraldehyde (chloral). Chloral hydrate. Chloral hydrate—Chloral (TJ. S.)—is a white, crystalline solid ; fuses at 57° (134°.(5 F.); boils at 98° (208°.4 F.), at which tempera- ture it suffers partial decomposition into chloral and H20 ; vola- tilizes slowly at ordinary temperatures ; is very soluble in H20 ; neutral in reaction ; has an ethereal odor, and a sharp, pungent taste. Concentrated H2S04 decomposes it with formation of chloral and chloralid. HN03 converts it into trichloracetic acid. When pure it gives no precipitate with silver nitrate solution, and is not browned by contact with concentrated H2S04. Under the influence of sunlight it is violently decomposed by potassium chlorate. Chlorin, phosgene gas, carbon dioxid, and chloroform are given off, and after a time, crystals of potassium trichlor- acetate separate from the cooled mixture. Chloral also combines with alcohol, with elevation of tem- perature, to form a solid, crystalline body—chloral alcoholate : nrii fin/OH 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 Lie- breich, and although this decomposition was at one time believed to occur in the body under the influence of the alkaline reaction of the blood, more recent investigations have shown that the formation of chloroform from chloral in the blood is, to say the least, highly improbable, and the chloral has, in common with MANUAL OF CHEMISTKY. many other chlorinated derivatives of this series, the property of acting directly upon the nerve-centres. Neither the urine nor the expired air contains chloroform when chloral is taken internally; when taken in large doses, chloral appears in the urine. The fact that the action of chloral is pro- longed 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 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. 234. 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 sus- pected liquid is rendered acid and tested as before. A negative result is obtained in the second testing when chloral is present. Bromal—CBr3,COH—281.—A colorless, oily, pungent liquid ; sp. gr. 3.34 ; boils at 172° (341°.6 F.); neutral ; soluble in H20, alcohol, and ether. It combines with HaO to form bromal hydrate, CBr3,CH(OH)2; large transparent crystals ; soluble in H20 ; de- composed by alkalies into bromoform and a formiate. Produces anaesthesia without sleep ; very poisonous. Thioaldehydes.—By the action of H2S on aldehyde in the pres- ence of HC1 two products are obtained, having the composition (CH3CSH)3, known as a and /3 Trithioaldehyde. The former is in large prismatic crystals, fusible at 101° (213°.8 F.), the latter in long needles, fusible at 125°-126° (257°-258°.8 F.). Propaldehyde — Propionic aldehyde — CH3,CH2,COH — 58—ob- tained by the general reaction from propylic alcohol, is a colorless liquid, resembling acetic aldehyde ; boils at 40° (120°.2 F.). Normal Butaldehyde—Butyric aldehyde—CH3,CH2,CH2,COH— 72—is an oily liquid, boiling at 73° (163°.4 F.). Its trichlorinat- ed derivative, Trichlorbutaldehyde, or Butyric chloral, CC13, CH2.COH —is the substance whose hydrate is used as a medicine ACETALS, KETONES OK ACETONES. 271 under the name croton chloral hydrate. It is a colorless liquid, boiling at 1(50° (3205 F.), obtained by the action of Cl on acet- aldehyde. These substances may be considered as derived from the alde- hydes by the substitution of two groups OR (R = an alcoholic radical CnHan + i) for the O of an aldehyde. ACETALS. Methylal—Formal—CH: qCh |—^—is formed by distilling a mixture of MnOa, methyl alcohol, HaS04 and HaO. It is a color- less liquid ; sp. gr. 0.8551 at 17° (62°.6 F.), boiling at 42° (107°.6 F.) ; soluble in HaO, alcohol, and oils. It has a burning, aromatic taste and an odor resembling those of chloroform and acetic acid. It has been used as a hypnotic. Acetal—CH... qCPhI—^—a c°l°rless liquid, boils at 104° (219 .2 F.), sp. gr. 0.8314 ; sparingly soluble in H20, readily in al- cohol ; obtained by heating a mixture of aldehyde, alcohol and glacial acetic acid, or in the same manner as formal, using ethylic in place of methylic alcohol. KETONES OR ACETONES. SERIES CnHanO. These substances all contain the group of atoms (CO) ', and their constitution may be represented graphically thus : oh3 io I ch3 ch3 I CO iii3 ch3 Dimethyl ketone (acetone). Methyl-ethyl ketone. the first being a symmetrical ketone and the latter an unsym- metrical. 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 aldehyde, and a secondary alcohol with a ketone : COH CHaOH OH* -+■ H* = CH* CH3 ch3 Proprionic aldehyde. Propyl alcohol. MANUAL OF CHEMISTRY. ch3 ch3 io + H, = (yH,OH CH3 CH, 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 CHj + O = CH, klla CH, Propionic aldehyde. Propionic acid. CH3 CO,OH CO,OH CO + 03 = I + H CH3 ch3 Acetone. Formic acid. Acetic acid. Dimethyl ketone—Acetone—Acetylmethylid—Pyroacetic ether or spirit—CO ( qjj—58—is formed as one of the products of the dry distillation 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, collected in a well-cooled receiver, is freed from HaO by digestion with fused calcium chlo- rid, and rectified ; those portions being collected which pass over at 60° (140° F.). It is also formed in large quantity in the prepa- ration of anilin. It is a limpid, colorless liquid; sp. gr. 0.7921 at 18° (64°.4 F.); boils at 56° (132°.8 F.); 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 chlo- rinated 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 cer- tain pathological conditions, and notably in diabetes ; the pecu- liar odor exhaled by diabetics is produced by this substance, NITROPARAFFINS. 273 which has also been considered as being the cause of the respira- tory 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 certain, however, that its presence produces the condition designated as acetonaemia. It can hardly be doubted that the acetone thus existing in the blood is indirectly formed from dia- betic sugar, and it is probable also that a complex acid, known as ethyldiacetic, C6H903H, is formed as an intermediate product. See aromatic ketones. NITROPARAFFINS. There exist two distinct isomeric series having the composition CnH2n + iNOa. One contains the true nitrous ethers (see com- pound ethers), formed by the substitution of the hydrocarbon radical for the hydrogen of nitrous acid, and having the consti- tution 0 = N—O, CH3 = methyl nitrite. The other contains substances in which the hydrocarbon radical is directly attached to the N atom, which may be considered as paraffins in which the group (NOa) has taken the place of an atom of hydrogen, and -O have the constitution | )N—CH3 = nitromethane. CK These bodies are formed by the action of the monoiodic deriva- tives of the paraffins upon silver nitrite : CHJ + AgNOa = Agl + OaNCHa Methyl iodid. Nitromethane. These are converted by nascent hydrogen into amidoparaffins or monamins : OaNCIT, + 3Ha = HaNCH3 + 2HaO These are decomposed by H3SO4 or HC1 into hydroxylammo- nium salts, and acids CnHanOa, containing all the C • Nitromethane. Methylamin Nitroethane. + H20 = CH,,C00(NH40) Hydroxylammonium acetate. Nitrous acid converts the primary nitroparafflns into powerful acids, called nitrolic acids, having the general formula : CnHan + i /yOH —C 2 ’ But the same agent converts the secondary ni- troparaffins into pseudonitrols, having the general formula: C?iH2n +1 \ p / NO CnH2n + l/U\N02- 274 MANUAL OF CHEMISTRY. MONAMINS—AMIDOPARAFFINS. The monamins are substances which may be considered as be- ing derived 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, accord- ing as they contain one, two, or three alcoholic radicals : H I N—H I H H I N—CH2—CH3 1 1 H H N—CH3—CH3 ch2—ch3 ch2—ch3 I N—CH,—CH3 ch2—ch3 Ammonia. nh3 (C2H6)H2N Ethylamin (primary). (C2Hs)sHN Diethylamin (secondary). (C2H5)3N Trietliylamin (tertiary). They are also known as compound ammonias, and resemble ammonia in their chemical properties ; uniting with acids, with- out elimination of H20, to form salts resembling those of ammo- nium. They also combine with H20 to form quaternary ammo- nium hydrates, similar in constitution to ammonium hydrate. The alkalinity and solubility in H20 of the primary monamins are greater than those of the secondary, and those of the secondary greater than those of the tertiary. Their chlorids form sparingly soluble compounds with platinic chlorid. The primary monamins are formed by the action of potassium hydrate upon the corresponding cyanic ether : CNOC2H5 + 2KHO = NH2C2H. + C03K2 Ethyl cyanate. Potash. Ethylamin. Potassium carbonate. or by heating together an alcoholic solution of ammonia and an ether: C2H6I + NH3 = HI + NH2C2H6 Ethyl iodid. Ammonia. Hydriodic acid. Ethylamin. or by the action of nascent H upon the cyanids of the alcoholic radicals : CNCH3 + 2H2 = NH2C2HS Methyl cyanid. Hydrogen. Ethylamin The secondary monamins are formed by the action of the iodids or bromide of the alcoholic radicals upon the primary monamins : NHsC2Hs + C2H5I = NH(C2H.)2 + HI Ethylamin. Ethyl iodid. Diethylamin The tertiary monamins are produced by the distillation of the MONA MINS—AMIDOPARAFFINS. hydrates or iodids of the quaternary ammoniums, or by the action of the iodids of the alcoholic radicals upon the secondary monamins. It is obvious from the above-described properties of these sub- stances that they are true alkaloids, among which also belong the diamins and triamins. Methylamin—Methylia—^^3 [ N—31—is a colorless gas ; has a fishy, ammoniacal odor; inflammable; is the most soluble gas known, one volume of H20 dissolving 1,154 volumes of methylia at 12°.5 (54°.5 F.). The aqueous solution possesses the odor of the gas, and is highly caustic and alkaline. It neutralizes the acids with forma- tion of methylammonium salts (e.y., CH3H3NNO3 = methylam- monium nitrate), which are for the most part crystallizable and very soluble in HaO. Its chloraurate crystallizes in beautiful golden-yellow needles, soluble in water, alcohol, and ether. Its chloroplatinate crystallizes in golden-yellow scales, soluble in water, insoluble in alcohol. See trimethylamin, below. Dimethylamin—Dimeihylia—v 3j'| N—45—is a liquid below 8 (4G°.4 F.); has an ammoniacal odor, and is quite soluble in H20. It constitutes about 50 per cent, of the commercial trimethyl- amin, which also contains 5 to 10 per cent, of trimethylamin, the remainder being a mixture of monomethylamin, isobutyl- amin, and propylamin. Its chloroplatinate forms long needles. See trimethylamin, below. Trimethylamin—TrimetJiylia—(CH3)3N —59—is formed by the action of methyl iodid upon NH3, and as a product of decompo- sition of many organic substances, it being one of the products of the action of potash on many vegetable substances, alkaloids, etc. It also occurs naturally in cod-liver oil, ergot, chenopo- dium, yeast, guano, human urine, the blood of the calf, and many flowers. It is an oily liquid, having a disagreeable odor of fish; boils at 8° (48°.2 F.) ; alkaline ; soluble in H20, alcohol, and ether ; in- flammable. It combines with acids to form salts of trimethyl- ammonium, which are crystallizable. Trimethylamin has long been known to exist in the pickle in which herrings have been preserved. More recently it has been found to be an important product of putrefactive changes in fish, starch-paste, brain-tissue, muscular tissue, and other albuminoid substances, being accompanied by lesser quantities of mono- methylamin, dimethylamin, ethylamin, and diethylamin, as well as by other peculiar alkaloidal bodies. It has also been observed accompanying more active alkaloids in blood-serum, etc., which 276 MANUAL OF CHEMISTRY. have served for the culture of various bacilli. See cholin and neurin, below, and ptomains. Its chloroplatinate crystallizes in octaliedra, insoluble in alco- hol. The commercial trimethylamin, obtained by the dry distilla- tion of distillery- waste, contains but per cent, of the substance whose name it bears. (See dimethylamin, above.) It has fre- quently been mistaken by writers upon materia medica for its isomere propylamin, j- N, which differs from it in odor, and in boiling at 50° (122° F.). Its chlorid, under the names chlorid of propylamia, of secalia, of secalin, has been used in the treat- ment of gout and of rheumatism. Tetramethyl ammonium hydrate—(CH3),NOH—91.—This sub- stance, whose constitution is similar to that of ammonium hy- drate, is obtained by decomposing the corresponding iodid (CHahNI, formed by the action of methyl iodid upon trimethyl- amin. It is a crystalline solid ; deliquescent; very soluble in H20 ; caustic; not volatile without decomposition. It attracts carbon dioxid from the air, and combines with acids to form crys- tallizable salts. The iodid is said to exert an action upon the economy similar to that of curare. Cholin—Trimethyloxeihylammonium hydrate— OH) | N,0H=C6Hi6N02—121—is a quaternary monam- monium hydrate, containing three methyl groups and one ethyl- ene hydroxid (oxethyl) group. It does not occur in the normal body in the free state, but is widely disseminated as a compo- nent part of an exceedingly important class of substances, the lecithins. It is also obtained from bile and from the yolk of eggs. It is one of the earliest products of cadaveric putrefaction, resulting, in all probability, from decomposition of the lecithins. Cholin has been obtained synthetically by the action of a con- centrated solution of trimethylamin upon ethylene oxid, or upon ethylene clilorhydrin. When heated, it splits up into glycol and trimethylamin. It appears as a thick syrup, soluble in H20 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 dioxid from the air ; forms with HC1 a salt, soluble in alcohol, which crystallizes in plates and needles, very much resembling in ap- pearance those of cholesterin. Its chloroplatinate is purified with difficulty ; its chloraurate readily. Solutions of its chlorid differ in their behavior with alkaloidal reagents from those of neurin MOXAMINS—AMIDO PARAFFINS. 277 in forming no precipitate with tannic acid, and in forming a vo- luminous white precipitate with phospliomolybdic acid, which becomes crystalline on standing. Administered hypodermically to animals it causes muscarin- like intoxication, although much less intense in its action than either that alkaloid or neurin. Axa.sinitiD.—Trimethyloxethylideneammoniuin hydrate— (CH —CHOHi (' N,OH = C6H15NOa—121—is an isomere of cholin existing along with muscarin (see below) in Agaricus muse arms. By oxidation with HN03 it yields muscarin. Muscarin— o ) = CsH16NOv—is a substituted tetra- methylammonium hydrate closely related to cholin andamanitin, from the former of which it may be obtained by oxidation. It occurs in nature in Agaricus muscarius, and is produced during putrefactive decomposition of albuminoid substances. The free alkaloid occurs in very deliquescent, irregular crystals, or, if not perfectly dry, a colorless, odorless, and tasteless, but strongly alkaline syrup; readily soluble in all proportions in water and in alcohol; very sparingly soluble in chloroform ; in- soluble in ether. It is a more powerful base than ammonium hydrate, forming an alkaline carbonate and neutral salts with other acids. When decomposed it yields trimethylamin. Its chloroplatinate crystallizes in octahedra. Its chlorid forms color- less, brilliant, deliquescent needles. When administered to animals, muscarin causes increased se- cretion of saliva and tears ; vomiting ; evacuation of f*ces, at first solid, later liquid ; contraction of the pupils, almost to the extent of closure ; diminution of the rapidity of the pulse ; inter- ference with respiration and locomotion ; gradual sinking of the heart’s action and respiration ; and death. Atropin prevents the action of muscarin, and diminishes its intensity when already established. /CH-) ) Neurin—Trimethylvinylammonium hydrate—(C . NOH — C5H13NO —is a substance nearly related to cholin, and long con- founded with it, supposed by Liebreich to exist in the brain. The same body is one of the alkaloids produced by the putrefac- tion of muscular tissues, and is endowed with poisonous quali- ties, resembling, but less intense than, those of muscarin. Another cadaveric alkaloid, related to neurin and produced under similar conditions, is a diamin: neuridin, C5H,4N3. 278 MANUAL OF CHEMISTRY. MONAMIDS. These bodies differ from the amins in containing oxygenated, or acid radicals, in place of alcoholic radicals. Like the amins, they are divisible into primary, secondary, and tertiary. They are the nitrids of the acid radicals, as the amins are the nitrids of the alcoholic radicals. The monamids may also be regarded as the acids in which the OH of the group COOH has been replaced by (NHS) : ch3 I COOH CH3 I CONH2 The primary monamids, containing radicals of the acids of the acetic series, are formed : (1.) By the action of heat upon an arn.- moniacal salt : Acetic acid. Acetamid. (0-hnS)>=SK(C-%)> Ammonium acetate. Water. Acetamid. (2.) By the action of a compound ether upon ammonia : (0<7S—515—exists as its sodium salt in the bile of man and of the carnivora, and in much less abun- dance in that of the herbivora. In the bile of the dog it seems to be unaccompanied by any other biliary acid. It may be obtained from dog’s bile by a modification of the method described under glycocholic acid ; the watery solution is not treated with H2S04, as in the preparation of that acid, but with solution of basic lead acetate and ammonia. 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 sulphid, 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. It forms silky, crystalline needles, which, when exposed to the air, deliquesce rapidly, and which, even under absolute 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 polarization to the right, [a]D= +24°.5; its solu- tions are acid in reaction. Taurocholic acid is decomposed by heating with barium hy- drate, with dilute acids, and even by evaporation of its solution, into cholic acid and taurin : C26H46NO,S + H.O = C24H40O6 + c2h7no3s Taurocholic acid. Water. Cholic acid Taurin. The same decomposition occurs in the presence of putrefying material, and in the intestine. Taurocholic acid lias not been found to accompany glycocholic in the urine of icteric patients. The taurocholates are neutral in reaction ; those of the alka- line 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 glycocholates in watery solution, either : (1) by dilute H2S04 in the presence of a small quantity of ether, which precipitates glycocholic acid alone ; or (2) by adding neu- AMIDO-AC'IDS OF THE FATTY SERIES. 287 tral lead acetate to the solution of the mixed salts (which must be neutral in reaction) lead glycocholate is precipitated and separated by filtration. To the mother liquor basic lead acetate and ammonia are added, when lead taurocliolate is precipitated. The acids are obtained from the hot alcoholic solutions of the Pb salts by decomposition with HaS, filtration, 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 Ha0, but soluble in an excess of the biliary salt. The taurocliolate of morphin is crystallizable. They react with Pettenkofer’s test. Hyoglycocholic acid, and Hyotaurocholic acid, CjH40NO6S (?), are conjugate acids of hyocholic acid, C2SH4„Ot, and glycocol and taurin, which exist in the bile of the pig. Chenotaurocholic acid, a conjugate acid of taurin and chenocholic acid, CiiHuOt, is obtained from the bile of the goose. Cholic acid—C24H!0O5—408—is a product of decomposition of glyco- and taurocliolic acids, obtained as indicated above. It also occurs, as the result of a similar decomposition, in the intestines and fgeces of both herbivora and carnivora. It forms large, clear, deliquescent crystals ; sparingly soluble in HaO, readily soluble in alcohol and ether; intensely bitter in taste, with a sweetish after-taste. In alcoholic solution it is dextrogyrous [a]D = +35’. The alkaline cholates are crystallizable and readily soluble in HaO, 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 HaO, and is transformed into dyslysin, C2 iH:i60.i, a neutral, resinous material, insoluble in HaO and alcohol, sparingly soluble 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 H2S04, the color of which rapidly increases in intensity, and which exhibits a green fluorescence. Their watery solutions also, when treated with a small quantity of cane-sugar and with con- centrated H2SO4, so added that the mixture acquires a tempera- ture 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 ob- served in the presence 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 H2SO4 alone, or in the presence of cane-sugar. Among 288 MANUAL OF CHEMISTRY. these substances are many which exist naturally in animal fluids, or which may be introduced with the food or as medicines ; such are cliolesterin, the albuminoids, lecithin, oleic acid, cerebrin, phenol, turpentine, tannic acid, salicylic acid, morpliin, codein, many oils and fats, cod-liver oil, etc. The following method of applying Pettenkofer’s test to the urine and 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 alco- hol, the alcoholic liquid filtered, partially evaporated, and treated with ten times its bulk of absolute ether ; after standing an bour or two, any precipitate which may have formed is collected upon a small filter, washed with ether, and dissolved in a small quan- tity of H20 ; 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 H2S04 are added ; the ad- dition 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 presence 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. Physiological Chemistry of the Biliary Acids. —These sub- stances are formed in the liver, and they are not reabsorbed from the intestine unchanged. Solutions 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 disintegra- tion of the blood-corpuscles. In large doses (2-4 grains [80-60 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 injec- tion 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 ffeces ; 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 simi- lar extracts of the contents of the lower part of the large intes- tine, or of the faeces, fail to give the reaction, and consequently are free from glyco- or taurocholic, cholic acid, or dy sly sin ; the faeces, moreover, do not contain either taurin or glvcocol. During the processes which take place in the intestine, the bile-acids are de- composed into cholic acid and taurin 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 in- testinal digestion. AM IDO-AC IDS OF THE FATTY SERIES. 289 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 con- siderably, as shown by the following analyses : I. II. in. IV. V. VI. VII. VIII. IX. Mucin 2.66 2.98 2.91 1.45 2.48 1.29 1 .... 1.29 Cholesterin .... 0.16 0.26 ) j 0.25 0.25 0.34 .... 0.35 Fats 0.32 0.92 f j 0.04 f 0.05 0.36 0.73 Taurocholate) of sodium, [ Glycocholate | 7.22 9.14 10.79 5.65 [.... 0.75 1.93 ! 1.57 0.87 of sodium, J [4.48 2.09 0.44 4.90 3.03 Soaps 0.64 0.82 1.63 1 1.46 1.39 Mineral salts... 0.65 0.77 1.08 0.63 3.86 0.46? 1.46? 1.... 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, *t. 18, killed by a fall. II. Fre- richs : Male, pet. 22, died of a wound. III. Gorup-Besanez : Male, ?et. 49, decapitated. IV. Gorup-Besanez : Female. pet. 29, decap- itated. V. Jacobsen: Male, biliary fistula. VI., VII. Trifanow- ski : 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. Creatin—C,H,N:,0- + Aq —13118—is another complex amido- acid, which occurs as pi normal constituent of the juices of mus- cular 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 percent. It is soluble in boiling HaO and in alcohol, insoluble in ether; crystallizes in brilliant, oblique, rhombic prisms ; neutral, taste- less, loses aq at 100° (212° F.); fuses and decomposes at higher temperatures. When long heated with HaO or treated with con- centrated acids, it loses HaO, and is converted into creatinin. Baryta water decomposes it into sarcosin 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 tempera- tures, rapidly at 100° (212° F.). A white precipitate, which turns 290 MANUAL OF CHEMISTRY. black when heated, is also formed when a solution of creatin is similarly treated with mercuric ehlorid and potash. Creatinin—C,H7N,0—113—a product of the dehydration of crea- tin, is a normal and constant constituent of the urine and arnni- otic fluid, and also exists in the blood and muscular tissue. It crystallizes in oblique, rhombic prisms, soluble in and in hot alcohol, insoluble in ether. It is a strong base, has an alkaline taste and reaction ; expels NH3 from the ammoniacal salts, and forms well-defined salts, among which is the double clilorid of zinc and creatinin, (C-tHvNsOLZnCL, obtained in very sparingly soluble, oblique prismatic crystals, when alcoholic solutions of creatinin and zinc ehlorid are mixed. The quantity of creatinin 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 pro- gressive muscular atrophy. It is obtained from the urine by precipitation with zinc ehlorid. Xanthin—Xanthic oxid— TJrous acid—CsHjN^j—152—occurs in a rare form of urinary calculus ; in the 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 HaO. If dissolved in HN03 and the solution evaporated, xanthin leaves a yellowish residue, which turns red- dish-yellow on the addition of potash solution, and violet-red when heated. Xanthin 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. Hypoxanthin—Sarcin—C5H,N40—136—occurs in the spleen, muscular tissue, thymus, suprarenal capsules and brain of mam- mals ; in the liver in acute yellow atrophy; and in the blood and urine in leucocythsemia. It may be obtained from the mother liquor of the preparation of creatin (q.v.). It forms nodular masses; soluble in 300 parts of cold, and 78 parts of boiling H30. It is produced from uric acid or from xan- thin by the action of sodium amalgam, and when oxidized by HNOs it yields xanthin. Guanin—C ,H ,N;>0—151—occurs in guano, in the excrements of the lower animals, and in the pancreas, lungs, and liver of cer- tain mammalians. It is a white or yellowish, amorphous, odor- less and tasteless solid; almost insoluble in H30, alcohol and ether ; readily soluble in acids and alkalies, with which it forms compounds. Carnin— + HaO—196+18—is obtained from Liebig’s AZOPARAFFINS—CYANOGEN COMPOUNDS. 291 meat extract in chalky, microscopic crystals, readily soluble in warm H30. It forms compounds with acids and alkalies, similar to those of hypoxanthin. AZOPARAFFINS—NITRILS—CYANOGEN COMPOUNDS These substances may be considered either as compounds of the univalent radical cyanogen, (C*v N")' ; or as paraffins, CnHjn + j, in which three atoms of hydrogen have been replaced by a trivalent N atom, hence azoparaffins ; or as nitrils, com- pounds of N with the trivalent radicals CnHan-j. Dicyanogen—(CUb—52—is prepared by heating mercuric cyanid. It is a colorless gas ; has a pronounced odor of bitter almonds ; sp. gr. 1.80(54 A.; burns in air with a purple flame, giv- ing off N and C02. It is quite soluble in H20, the solution turn- ing brown in air. It has a very deleterious action upon both animal and vegeta- ble life, even when largely diluted with air. Hydrogen cyanid—Cyanogen h yd rid—Hydrocyanic acid—Prus- CH ) sic acid— jj ■—27—exists ready formed in the juice of cassava, and is formed by the action of H30 upon bitter almonds, cherry- laurel leaves, etc. It is also formed in a great number of reactions: by the passage of the electric discharge through a mixture of acetylene and N ; by the action of chloroform on NH3 ; by the distillation of, or the action of HN03 upon many organic sub- stances ; by the decomposition of cyanids. It is always prepared by the decomposition of a cyanid or a ferrocyanid. Usually by acting upon potassium ferrocyanid with dilute sulphuric acid, and distilling. Its preparation in the pure form is an operation attended with the most serious danger, and should only be attempted by those well trained in chemical manipulation. For medical uses a very dilute acid is required ; the acid hydrocyanicum dil. (U. S., Br.) contains, if freshly and properly prepared, two per cent, of anhydrous acid. That of the French Codex is much stronger—ten per cent. The pure acid is a colorless, mobile liquid, has a penetrating and characteristic odor ; sp. gr. 9.7058 at 7° (443.6 F.); crystallizes at —15° (5° F.); boils at 26 .5 (79 .7 F.); is rapidly decomposed by exposure to light. The dilute acid of the U. S. P. is a colorless liquid, having the odor of the acid ; faintly acid, the reddened litmus returning to blue on exposure to air; sp. gr. 0.997; 10 grams of the acid should be accurately neutralized by 1.27 gram of silver nitrate. The dilute acid deteriorates on exposure to light, although more slowly than the concentrated; a trace of phosphoric acid added to the solution retards the decomposition. 292 MANUAL OF CHEMISTRY Most strong acids decompose HCN. The alkalies enter into double decomposition with it to form cyanids. It is decomposed by Cl and Br, with formation of cyanogen chlorid or bromid. Nascent H converts it into methylamin. Analytical Characters.—(1.) With silver nitrate a dense, white ppt. ; which is not dissolved on addition of HN03 to the liquid, but dissolves when separated and heated with concentrated HNOa; soluble in solutions of alkaline cyanids or hyposul- phites. (2.) Treated with NH4HS, evaporated to dryness, and ferric chlorid added to the residue ; a blood-red color. (£5.) With potash and then a mixture of ferrous and ferric sulphates; a greenish ppt., which is partly dissolved with a deep blue color by HC1. (4.) Heated with a dilute solution of picric acid and then cooled ; a deep red color. (5.) Moisten a piece of filter paper with a freshly prepared alcoholic solution of guaiac; dip the paper into a very dilute solution of CuS04, and, after drying, in- to the liquid to be tested. In the presence of HCN it assumes a deep blue color. Toxicology.—Hydrocyanic acid is a violent poison, whether it be inhaled as vapor, or swallowed, either in the form of dilute acid, of soluble cyanid, or of the pharmaceutical preparations containing it, such as oil of bitter almonds and cherry-laurel Avater ; its action being more rapid when taken by inhalation or in aqueous solution than in other forms. When the medicinal acid is taken in poisonous dose, its lethal effect may seem to be produced instantaneously ; nevertheless, several respiratory efforts usually are made after the victim seems to be dead, and instances are not wanting in which there was time for consider- able voluntary motion between the time of the ingestion of the poison and unconsciousness. In the great majority of cases the patient is either dead or fully under the influence of the poison on the arrival of the physician, Avho should, howeATer, not neg- lect to apply the proper remedies if the faintest spark of life re- main. Chemical antidotes are, owing to the rapidity of action of the poison, of no avail, although possibly chlorin. recom- mended as an antidote by many, may haAre a chemical action on that portion of the acid already absorbed. The treatment indi- cated is directed to the maintenance of respiration ; cold douche, galvanism, artificial respiration, until elimination has remoATed the poison. If the patient survive an hour after taking the poison, the prognosis becomes A’erv favorable ; in the first stages it is exceedingly unfaxTorable, unless the quantit y taken has been very small. In cases of death from hydrocyanic acid a marked odor of the poison is almost ahvays obser\red in the apartment and upon opening the body, even several days after death. In cases of AZOPARAFFINS—CYANOGEN COMPOUNDS. 293 suicide or accident, the vessel from which the poison has been taken will usually be found in close proximity to the body, al- though the absence of such vessel is not proof that the case is necessarily one of homicide. Notwithstanding the volatility and instability of the poison, its presence has been detected two months after death, although the chances of separating it are certainly *tlie better the sooner after death the analysis is made. The search for hydrocyanic acid is combined with that for phosphorus ; the part of the dis- tillate containing the more volatile products is examined by the tests given above. It is best, when the presence of free hydrocy- anic acid is suspected, to distil at first without acidulating. In cases of suspected homicide by hydrocyanic acid the stomach should never be opened until immediately before the analysis. Cyanids.—The most important of the metallic cyanids are those of K and Ag (see pp. 190, 193). The hydrocyanic ethers of the univalent alcoholic radicals are called nitrils, and are frequently the starting-points from which other organic products are obtained. They are produced : 1.) By distilling a mixture of potassium cyanid and the potas- sium salt of the corresponding monosulphate of the alcoholic radical : KCN + SOaK 1O* = CaH5,CN + K2S04 Potassium cyanid. Potassium ethylsulphate. Ethyl cyanid. Dipotassic sulphate. 2.) By complete dehydration, by the action of P206, of the am- moniacal salt of the corresponding acid, or of its amid : CH3,COO(NH4) = CH3,CN + 2HaO Ammonium acetate. Methyl cyanid. CH3,CO,NHa = CH3,CN .+ HaO Acetamid. Acetonitril. 3.) By the action of the chloridsof the acid radicals upon silver cyanate : CNOAg + CHsCOCl = AgCl + CH3CN + COa Silver cyanate. Acetyl chlorid. Methyl cyanid. The nitrils combine with nascent hydrogen to form the corre- sponding amins : CH3,CN + 2H, = CaH6,HaN. Acetonitril. Ethylamin. Hydrating agents convert the nitrils into ammonia and the corresponding acid: 294 MANUAL OF CHEMISTRY. Propionitril. C2H6,CN + 2HaO = NH, + CaH6,COOH Propionic acid. Sulphuric acid, or sulphur trioxid, converts the nitrils into sul- plio-acids and monoammonic sulphate : C2H5,CN + H20 + 2H2SC>4 = NHjH(S04) + S03,CaH6,C00H Ethylcyanid. Sulphopropionic acid. Isomeric with the nitrils are substances known as isocyanids, carbylamins or carbamins, which are formed : 1.) By the action of a primary monamin on chloroform in the presence of caustic potash : CH3,HsN + CHCh = 8HC1 + CN,CHa Methylamin. 2.) By the action of the iodoparaffins on silver cyanid : Methyl isocyanid. CHJ + AgCN = Agl + CN,CHS Methyl iodid. Methyl carbylamin. The difference in the constitution of the two classes of bodies is due to the N being trivalent in the nitril, and quinquivalent in the carbylamin : N=C—CH3 C=N—CH3 Methyl cyanid. Methyl isocyanid. The isocyanids do not yield ammonia and an acid by the action of hydrating agents, but are converted into formic acid and a primary amin : NC,C2H6 + 2HsO = NHs,C2H, + H.COOH Ethyl isocyanid. Ethylamin. Formic acid. The nitrils and carbamins combine with the hydracids to form crystalline salts, decomposable by water. The latter much more energetically than the former. They are all volatile liquids ; the nitrils having ethereal odors when pure, the isocyanids odors which are very powerful and disagreeable. Cyanogen clilorids. — Two polymeric chlorids are known. Gaseous cyanogen chlorid—CNC1—is formed by the action of Cl upon anhydrous hydrocyanic acid or upon mercuric cyanid in the dark. It is a colorless gas, intensely irritating and poisonous. Solid cyanogen chlorid—C3N;iCl3—is formed, as a crystalline solid, when anhydrous hydrocyanic acid is acted upon by Cl in sunlight. It fuses at 140° C. (284° F.). Cyanic acid—Cyanogen hydrate—O—48—does not exist in nature. It is obtained by calcining the cyanids in presence of an oxidizing agent; or by the action of dicyanogen upon solutions of AZOPARAFFINS—CYANOGEN COMPOUNDS. 295 the alkalies or alkaline carbonates ; or by the distillation of cya- nuric acid. It is a colorless liquid ; has a strong odor, resembling that of formic acid ; its vapor is irritating to the eyes, and it produces vesication when applied to the skin. It is soluble in water. When free it is readily changed by exposure to air into an iso- mere, cyamelicL The acid forms salts and ethers which constitute two isomeric series, indicating the existence of two acids, the normal, having the constitution NeeO—OH, and the iso, having the constitu- tion O = C = N—H. Ammonium isocyanate O = C = N—NH, is converted into urea by heat. Cyanuric acid—C3N;IH303—is a polymere of cyanic acid, formed by the action of heat or of Cl upon urea. It forms colorless crystals, sparingly soluble in H20, the solutions odorless, almost tasteless, and feebly acid. It is a tribasic acid. It is very stable and may be dissolved in strong HaSO< or HNOs without suffering decomposition. Fulminic acid—C2N.H..02—is a bibasic acid whose Ag and Hg salts are formed by the action of nitrous acid upon alcohol in the presence of the salts of Ag and Hg. These are the fulminating powders used in the manufacture of percussion caps. Fulminuric acid—C:iN3H:,03—metameric with cyanuric acid, is a bibasic acid, formed by the action of a metallic chlorid upon a solution of mercuric fulminate. Thiocyanic acid—Sulphocyanic acid—Cyanogen sulphytbate— CN x H^:S—59—bears the same relation to cyanic acid that CS2 does to COs. It is obtained by the decomposition of its salts, which are obtained by boiling a solution of the cyanid with S ; by the action of dicyanogen upon the metallic sulphid ; and in several other ways. The free acid is a colorless liquid ; crystallizes at —12°.5 (9°.5 F.); boils at 102°.5 (216 .5 F.); acid in reaction. The prominent re- action of the acid and of its salts is the production of a deep red 6olor with the ferric salts ; the color being discharged by solution of mercuric chlorid, but not by HC1. Sulphocyanic acid exists in human saliva in combination, probably with sodium. The free acid is actively poisonous and its salts were formerly supposed to be so also. It is probable, however, that much of the deleterious action of the potassium salt—that usually experimented with—is due as much to the metal as to the acid. Cyanamid—CN,NH,—is produced by the action of gaseous cyanogen chlorid upon ammonia : CNCl-f-2NH3 = JsH4Cl-l- 296 MANUAL OF CHEMISTRY. CN,NH2. It forms colorless crystals, soluble in water, alcohol or ether. Corresponding to it are substituted cyanamids, which may be formed by substituting a primary amin for ammonia in the above-mentioned method of preparation : CNCl-t-2NH2CH3 = NH3,CH3,C1+CN,NHCH3. Metallocyanids.—The radical cyanogen, besides combining with metallic elements to form true cyanids, in which the radical (CN) enters as a univalent atom, is capable of combining with certain metals (notably those of the iron and platinum groups) to form complex radicals. These combining with H, form acids, and with basic elements form salts in which the analytical re- actions of the metallic element entering into the radical are com- pletely masked. Of these metallocyanids the best known are those in which iron enters into the radical. As iron is capable of forming two series of compounds, in one of which the single atom Fe enters in its bivalent capacity, and in the other of which the hexavalent double atom (Fe2)vi is contained; so uniting with cyanogen, iron forms two ferrocyanogen radicals: [(CN)'6Fe"]iv, ferrocyanogen, and [(CN)'i2(Fe2)vi]vi ferricyanogen; each of which unites with hydrogen to form an acid, corresponding to which are numerous salts: (C6NfiFe)H4, hydroferrocyanic acid, tetra- basic; and (Ci2Ni2Fe2)H6, hydroferricyanic acid, hexabasic (see potassium and iron salts). SULPHUR DERIVATIVES OF THE PARAFFINS. Sulphur and oxygen, being equal in valence, may replace each other in organic compounds as, for instance, in sulphocyanic acid CNSH, corresponding to cyanic CNOH. There exist many derivatives of the paraffins in which S thus takes the place of O. Thus : CH2OH Ah. CjH6\n ri u i- i Li / O C 2 H 3 bti3_0ii\OCsHs Ethylic alcohol. Ethylic ether, or ethyl oxid. Acetal. CH2SH ch3 C2Hs\q C2H6/b /''crj fin/ SC2H 5 OM8-UlxSC|Ht Thioalcohol or mercaptan- Ethyl sulphid. Mereaptal. Methyl sulphids.—Three are known. The monosulphid,(CH3)2S, is a colorless liquid, boils at 41° (105°.8 F.), has a very disagreeable odor, as have all the alcoholic sulphids and sulphydrates. It is formed by the action of gaseous methyl chlorid on potassium monosulphid. The bisulphid, (CHs)2S2, is similarly formed fi*om SULPHUR DERIVATIVES OF PARAFFINS. 297 potassium bisulphid, and is a colorless liquid, boiling at 116°-118° (240 .8-244°.4 F.). The trisulphid (CH,),S3, is formed in the same way from potassium pentasulphid, and boils at 200° (392° F.). Ethyl sulphids are formed in the same manner as the methyl compounds, and have the same constitution. Methyl hydrosulphid—Methyl mercaptan—H.CH-SH—is a very offensive liquid formed by distilling together calcium methyl- sulphate and potassium hydrosulphid. Ethyl sulphydrate — Thioalcohol—Mercaptan—CHa, CH-SH—is best prepared by treating alcohol with HaSO«, as in the prepara- tion of sulphovinic acid (q.v.); mixing the crude product with excess of potash ; separating from the crystals of potassium sul- phate ; saturating with H2S ; and distilling. It is a mobile, colorless liquid ; sp. gr. 0.8325; has an intensely disagreeable odor, combined of those of garlic and H2S ; boils at 36 .2 (97°.2 F.); ignites readily and burns with a blue flame ; may be readily frozen by the cold produced by its own evaporation ; neutral in reaction ; sparingly soluble in HaO, soluble in all pro- portions in alcohol and ether ; dissolves I, S and P. Potassium and sodium act with mercaptan as with alcohol, re- placing the extra-radical hydrogen. In its behavior toward the oxids it more closely resembles the acids than the alcohols, being capable even of entering into double decomposition to form salts, called sulphethylates or mercaptids. Its action with mercuric oxid is characteristic, forming a white, crystalline sulphid of ethyl and mercury : 2(CaH&[S) + HS"° = (CaHg?[Sa + Ha° Ethyl sulphydrate. Mercuric oxid Ethyl-mercuric sulphid. Water- When a mixture of one molecule of a mercaptan with two molecules of an aldehyde is treated with dry HC1, a stable com- pound is produced which is called a mercaptal, being an acetal whose 0 is replaced by S. If the reaction take place with an acetone, in place of with an aldehyde, a mercaptol is produced, which differs from the mer- captal in that an alcoholic radical is substituted for the remain- ing H atom of the methane : H \n/OC2H5 H \n/SC2H5 CH3\p/SC2Hs CH3/u\OC2H5 CH3A\SC2H5 CH3/°\SC2H5 Acetal. Mercaptal. Mercaptol. Ethyl mercaptol—(CH3)2 = C = (SC3H5)—is formed as one of the steps in the manufacture of sulphonal. It is produced by the action of dry HC1 upon a mixture of acetone and ethylmer- captan, or upon a mixture of sodium ethylthiosulphate, 298 MANUAL OF CHEMISTRY. C2H6,SO,ONa, and acetone. It is a mobile liquid, whose odor is not disagreeable. When heated it begins to boil at about 80 (176° F.) and the temperature rises rather regularly to 192° (377°.6 F.). Oxidizing agents act readily upon the mercaptals and mercap- tols to produce compounds called sulphones, whose constitution is represented by one of the three following formula, in which R is a univalent alcoholic radical: H\n/S02R R\n/S02R H/°\S02R H/u\SOaR R/°\S02R Methylendisulplione. Methenyldisulphone. Ketondisulphone. C go C H —is obtained by the oxidation of ethyl-mercaptol, prepared as above described, by potassium permanganate. It crystallizes in thick, colorless prisms, difficultly soluble in cold water or alcohol, readily soluble in hot water or alcohol, and in ether, benzene and chloroform. It fuses at 130 -131° (266°-267°.8 F.), and boi.s at 300° (572° F.), suffering partial decomposition. It dissolves in concentrated H2S04, and is decomposed by the acid when heated, but may be precipitated from the cold solution unchanged by dilution with H20. Nitric acid does not affect it, even when heated. It is not attacked b}r Br, by caustic alkalies or by nas- cent H. Ichthyol—is the Na salt of a complex sulphonic acid, having the empirical formula C2hH36S3Na2OB, obtained by the distillation and purification of an ozocerite-like mineral deposit. It is a dark brown, pitch-like mass having a disagreeable odor. COMPOUNDS OF THE ALCOHOLIC RADICALS WITH OTHER ELEMENTS. Phosphins, arsins, and stibins, are compounds resembling the amins in constitution, in which the N is replaced by P, As, or Sb. Like the amins, they may be primary, secondary, or tertiary : CaH6 ) H [n H } CaHs ) H H \ CaHfi ) CaH 5 > As H i C2Hb -Sb C2Hb ) Ethylamin (primary). Ethylphospin (primary). Diethyl-arsin (secondary). Triethyl-stibin (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 compound ammoniums : Ammonium iodid. NHJ Tetramethyl ammonium iodid. N(CH,)J Tetramethyl arsenium iodid. As(CH3)4I COMPOUNDS OF THE ALCOHOLIC RADICALS. 299 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 ) Dimethyl Arsin, CH3 - As—106—which may be considered as H) being the hydrid of the radical [As(CH3)2], 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 potas- sium acetate and arsenic trioxid. This liquid contains the oxid of the above radical, and a substance which ignites on contact with air, and which consists of the same radical united to itself, 2[As(CHj)9]. This radical, called cacodyle («a/cof = evil), is capa- ble of entering into a great number of other combinations. Ca- codyle and its compounds are all exceedingly poisonous, espe- cially the cyanid, 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-metallic substances are compounds of the alcoholic radicals writh metals. They are very numerous, usually obtained by the action of the iodid of the alcoholic radical upon the me- tallic 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 mention : Zinc-ethyl — \ —obtained by heating at 130° (266° F.) in a sealed tube a mixture of perfectly dry zinc amalgam with ethyl iodid; the contents of the tube are then distilled in an atmosphere of coal-gas, or H, and the distillate collected in a receiver, in wrhich 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 oxid, a property which renders it very dan- gerous to handle. On contact with H30 it is immediately decomposed into zinc hydrate and ethyl hydrid. It is chiefly use- ful as an agent by which the radical ethyl can be introduced into organic molecules. MANUAL OF CHEMISTRY. ALLYLIC SERIES. The compounds heretofore considered may be derived more or less directly from the saturated hydrocarbons ; in the deriva- tives, as in the hydrocarbons, the valences of the C atoms are al*l satisfied, and that in the simplest and most complete man- ner, 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 therefore capa- ble of forming products of addition, while the saturated com- pounds 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 formulae indicate the constitution of the substances of this series, and their relation to those of the previous one. It will be observed that in the allyl compounds, two neighboring C atoms exchange two valences : CH3 I CHa CHaH or (C,Ht)' ) H f CH3 CHa CHaOH or (C»H^'|0 CH3 CH, I COH or (C3H60)' ) H \ ch3 CHa COOH or (C.H.O)' ) n H 'CH3 CHa CHa { I J (C3H,)' Propyl hydrid (hydrocarbon). Propyl hydrate (alcohol). Propionyl hydrate (aldehyde). Propionyl hydrate (acid). Propyl (radical). r ch5i 11 2 CH I l CHa or C3H5 ) C3Hb j ch3 f CH.OH or (CaHe)' [ q H ) u ch2 I COH or (CsH30)' ) H f ch2 fen i)OOH or (c3H3oy |0 rcH.'i Sh CHi l I J (CsH») Diallyl (hydrocarbon). Allyl hydrate (alcohol). Acrolein (aldehyde). Acrylic acid (acid). Allyl (radical). C. jj ) Diallyl—- —82—formerly known as allyl, is obtained by the action of sodium upon allyl iodid, and is not, as its empirical ALLYLIC SERIES. 301 formula would seem to indicate, a superior homologue of acety- lene and allylene (q. o.). It is a colorless liquid, having a peculiar odor, somewhat re- sembling that of horseradish ; boils at 59° (138°.2 F.); sp. gr. 0.684 at 14° (57°.2 F.). C H ) Vinyl hydrate—Vinyl alcohol— a - O—is produced by dis- tilling vinyl sulphuric acid, (C3H3)H,S04, formed by the action of HsiSChon acetylene, with HgO. It is an unstable liquid, having a very pungent odor. Allyl hydrate—Allylic alcohol—|- O—58—may be obtained by the action of sodium upon dichlorhydrin in ethereal solution ; or by heating four parts of glycerin with one part of crystallized oxalic acid. Allylic 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 HaO ; 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 ace- tone. Being an unsaturated compound, it is capable of forming products of addition with Cl, Br and I, etc., which are isomeric or identical with products of substitution obtained by the action of the same elements upon glycerin. Oxidizing agents convert it first into acrolein, acrylic aldehyde, C3H40, 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. Allyl oxid—Allylic ether—q3jj5 O—98—exists in small quan- tities in crude essence of garlic. It is obtained as a colorless liquid, having an alliaceous odor ; insoluble in HsO ; boiling at 82° (179°.6 F.), by a number of reactions, but best by the action of allyl iodid upon sodium-allyl oxid. C H ) Allyl sulphid—Essence of garlic—q3jj5 ( ®—114—is obtained by the action of an alcoholic solution of potassium sulphid upon allyl iodid ; also as a constituent of the volatile oil of garlic, by macerating garlic, or other related vegetables, in water, and dis- tilling. Crude essence of garlic is thus obtained as a heavy, fetid, brown oil ; this is purified by redistillation below 140° (284° F.) ; contact with potassium, and subsequent redistillation from calcium chlorid. It is a colorless, transparent oil; lighter than HaO, sparingly soluble in HtO, very soluble in alcohol and ether ; boils at 140° (280° F.) ; has an intense odor of garlic. It does not exist natu- rally in the plant, but is formed during the process of extraction MANUAL OF CHEMISTRY. by the action of H20, probably in a manner similar to that in which essence of mustard is formed under similar circumstances. It is to the formation of allyl sulphid, which is highly volatile, that garlic owes the odor which it emits. Allyl chlorid—C,H,C1 —a colorless liquid, boils at 46° (114°.8 F.), has an irritating odor ; formed by slowly adding PC13 to allyl alcohol. Allyl bromid—CaH5Br—a liquid boiling at 71° (159 .8 F.), ob- tained in the same manner as the chlorid, using PBr3. Allyl iodid—CaH,I —a colorless liquid having a peculiar odor ; boils at 101°.5 (214°.7 F.) ; insoluble in H20 ; obtained by carefully mixing allyl alcohol, red P, and I, and distilling after 24 hours. Allyl tribromid- (C3Hr,Br)s—a colorless liquid, very soluble in ether, boiling at 217° (422° F.), solidifying at —10° (14° F.); ob- tained by acting upon allyl iodid with 24 times its weight of Br. Has been recommended as a nervous sedative. Allyl sulphocyanate—Essential oil of mustard—Oleum sinapis volatile (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 proper- ties, and in being composed of the glycerids 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, pungent 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 collected, dried by contact with calcium chlorid, and redistilled. Essence of mustard may also be obtained synthetically by the action of allyl bromid or iodid upon potassium sulphocyanate, or by the action of allyl iodid upon silver sulphocyanate. This essence does not exist preformed in the mustard, but re- sults from the decomposition of a peculiar constituent of the seeds, potassium myronate, determined by cryptolytic action set up by another constituent, myrosin, 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. Myrosin is a nitrogenized cryptolite, existing in the white as well as in the black mustard, and in other seeds. It may be ob- tained from white mustard seeds, in an impure form, by extrac- ACIDS AND ALDEHYDES, ACRYLIC SERIES. tion with cold HaO, 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 HaO, and the solution evaporated below 40° (104 F.) to dryness. At temperatures above 40 (104 F.) myrosin becomes coagu- lated and incapable of decomposing potassium myronate, a change which is also produced by contact with acetic acid. As the rubefacient and vesicant actions of mustard when moistened with HaO, 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 148’ (289 .4 F.); has a penetrating, pungent odor, sparingly soluble in H >0, very soluble in alcohol and ether. When exposed to the light it gradually turns brown- ish-yellow and deposits a resinoid 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 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 potassium hydrate in fusion. C jj o / Acrylic acid— 3 jj - 0—72—is obtained by oxidation of acro- lein by silver oxid, and is formed in a number of other reactions. It is a colorless, highly acid liquid ; has a penetrating odor; solidifies at 7° (44°.6 P.) ; boils at 140’ (284’ F.). Nascent H unites with it to form propionic acid. It forms crystalline salts and ethers. C H O ) Acrylic aldehyde—Ally lie aldehyde—Acrolein— 3 jj —56.— When the fats and fixed oils are decomposed by heat, a disagree- able, irritating 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 HoSCh, 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 trivalent in place of univalent. 304 MANUAL OF CHEMISTRY. (C,H5)'"(OH), = 2HaO + (03H3O)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 volatile ; 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 vessels ; on standing it deposits a flocculent material, which has been called disocryl, while at the same time formic, acetic, and acrylic acids are formed. Oxidizing 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 con- taining 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 ori- gin for the lubricating of machinery operated in enclosed places. Crotonicacid— 4 —86—was first obtained from croton-oil, oleum tiglii (U. 8.), oleum crotonis (Br.), in which it exists in com- bination with glycerin, and accompanied by the glycerin ethers of several other fatty acids; it is, however, neither the vesicant nor the purgative principle of the oil. It may be obtained by saponification of croton-oil, or, better, by the action of potassium hydrate upon allyl cyanid. 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 isomere, as it is in the form of crystals at ordinary tempera- tures, and only fuses at 73° (163°.4 F.). Crotonic aldehyde—^4 j- —70.—If aldehyde. HaO, and HOI 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 C4H,02. This substance, known as aldol, when exposed to heat, is decomposed into water and crotonic aldehyde : C4H802 = H20-t-C4H60. 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. ACIDS AND ALDEHYDES, ACRYLIC SERIES. 305 C H O ) Angelic acid— 5 jj ' O—100—exists in angelica root, in the flowers 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° (305’ F.) ; has an aromatic odor and an acid, pungent taste ; sparingly soluble in cold HjO ; readily soluble in hot HaO, alcohol, and ether. By the action of heat it is converted into its isomere, methylcrotonic acid, C1H1(CHa)_0 / q C H O ) Oleic acid—Acidum oleicum (TJ. S.)— 1(1 3 jj j- 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, how- ever, 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 dis- solved 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 H2S04; insoluble in H20 5 sp. gr. 0.808 at 19° (66°.2 F.). Neutral in reaction. It can be dis- tilled in vacuo without decomposition, but when heated in con- tact with air, it is decomposed with formation of hydrocarbons, volatile fatty acids, and sebacic acid. It dissolves the fatty acids readily, forming mixtures whose consistency varies with the pro- portions 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. When heated with a small amount of chlorin, bromin or iodin under pressure to 270°-280° (518°-536° F.) for several hours, oleic acid is converted into a mixture of solid fatty acids containing 70 per cent, of stearic acid. Cl and Br under ordinary pressure attack oleic acid with for- mation 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 : Ci8H34 0 2 + 2KHO = CieHsiChK 4- C2H3O2K + H2 ; a reaction which is utilized industrially to obtain hard soaps, palmitates, from olein, which itself only forms soft soaps. Cold H2SO4 dissolves oleic acid, and deposits it unaltered 306 MANUAL OF CHEMISTRY. 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 alkali metals are soft, soluble soaps ; those of the earthy metals are in- soluble in H20, but soluble in alcohol and in ether. Elaidic acid is an isoinere of oleic acid, produced by the action upon it of nitrous acid in the preparation of TJnguentum hydrar- gyri nitratis (U. 8.; 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. SECOND SERIES OE HYDROCARBONS—OLEFINS. 807 SECOND SERIES OF HYDROCARBONS—OLEFINS. Series CnHan The terms of this series contain two H atoms less than the cor- responding 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 between two of the C atoms: c=h3 A=h2 I c=h3 c=h3 A-h II C=H2 Propane. Propylene. They are designated as olefins; 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 carbtiretted CH, hydrogen— || —28—is formed by the dry distillation of fats, CH3 resins, wood, and coal, and is one of the most important constit- uents 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 monoxid over iron or copper heated to redness; (2) by heating acetylene in the presence of H, or by the action of nascent H upon copper acetylid; (3) by the action of H upon the chlorid C2C14, obtained by the action of Cl upon carbon disulphid. It is prepared in the laboratory by the dehydration of alcohol: a mixture of 4 pts. H2S04 and 1 pt. alcohol is placed in a flask con- taining 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 containing H20, an alkaline solution, and concentrated H2S04. Pure ethylene is a colorless gas; tasteless; has a faint odor re- sembling that of salt water, or an ethereal odor when impure; irrespirable; sparingly soluble in H20, more soluble in alcohol. It burns with a luminous, white flame, and forms explosive mix- tures with air and oxygen. When heated for some time at a dull red heat it is converted into acetylene, ethyl and methyl hydrids, a tarry product, and carbon. Ethylene readily enters into combination. It unites with H to form ethyl hydrid, C2H6. With O it unites explosively on the approach of a flame, with formation of carbon dioxid and H20. 308 MANUAL OF CHEMISTliY. 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. Chlorin and ethene, mixed in equal volumes and exposed to diffused daylight, unite slowly, with formation of an oily liquid; ethene chlorid, C-HiCl2=Dutch. liquid, to whose formation ethene owes the name olefiant gas. By suitable means ethene may also be made to yield chlorinated products of substi- tution, the highest of which is carbon dichlorid, ChCl4. Br and I also form products of addition and of substitution with ethene. By union with (OH)2 it forms glycol (q.v.). It slowly dissolves in ordinary H2SO>, with formation of sulphovinic acid. With fuming H2SO4 it combines with elevation of temperature and for- mation of etliionic anhydrid. When inhaled, diluted with air, ethene produces effects some- what similar to those of nitrous oxid. Pentene—Amylene or valerene—Cr,H10—70—a colorless, mobile liquid, boiling at 39° (102°.2 F.); obtained by heating alcohol with a concentrated solution of zinc chlorid. Its use as an anaesthetic has been suggested. ch.2ci Ethene chlorid—Bichlorid of ethylene—Dutch liquid— | — CHjCl 99—is obtained by passing a current of ethene through a retort in which Cl is being generated, and connected with a cooled receiver. The distillate is washed with a solution of caustic potassa, after- ward with H20, and is finally rectified. It is a colorless, oily liquid, which boils at 82°.5 (180°.5 F.); has a sweetish taste and an ethereal odor. It is isomeric with the C2H4CI chlorid of monochlorinated ethyl, | , which boils at 64 “(147°.2 Cl F.). It is capable of fixing other atoms of Cl by substitution for H, and thus forming a series of chlorinated derivatives, the high- est of which is C2CI6. DIATOMIC ALCOHOLS Series CnHun+uO;,. These substances are usually designated as glycols. They are the hydrates of the hydrocarbons of the series CnH2n, and consist of those hydrocarbons, playing the part of bivalent radicals, united with two groups OH; their general typical formula is then (C»H2h) j. 02. We have seen (p. 238) that the primary monoatomic DIATOMIC ALCOHOLS. 309 alcohols contain the group of atoms (CH2OH), united with n(CnH3H + i); the primary glycols are similarly constructed, and consist of twice the group (CH3OH), united in the higher terms to n(CHi). The constitution of the glycols and their relations to the monoatomic alcohols are indicated by the following formulae: CHaOH I CHa ch3 CHaOH '('’Ha I CHaOH 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 alco- hols are therefore only capable of forming a single ether with a monobasic acid, the glycols are capable of forming two such ethers: Primary propyl alcohol. Primary propyl glycol. CHa(CaH3Oa) I ch3 CHa(CaH3Oa) CHaOH CHa(C3H302)' I CH3(C2H303)' / OH Methene glycol, which would have the composition HaC ( is not known. Its haloid ethers are, however, known. A con- densation product corresponding to it exists as methene dime- thylate, HjC OCH3’ a^so ca'*eOa—90.—There are probably three, certainly two, acids having this composition. Two of these would seem, from their products of decomposition, to be of similar constitu- tion, 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. Their constitution is expressed by the formulae: CH3 ' CH,OH I COOH CHaOH CHa COOH Ethylidene lactic acid, Ethyleno-lactic acid. Obviously it is the ethylene acid which is the superior homologue of glycollic 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. It is optically inactive, as are also solutions of its salts; its zinc salt contains 2 Aq, and is very solu- ble 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 ob- tained 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 laevogyrous. The specific rotary power of the acid is [a]D=-j-3°.5; that of the zincsalt [a]D= — 7°.G; and of the calcium salt [o]d=— 3°.8. Its prod- ucts of decomposition 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 fermentation 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 cer- tain sugars, milk-sugar and grape-sugar; as a result of the proc- esses of nutrition of a minute vegetable, the lactic ferment, in 314 MANUAL OF CHEMISTRY. which the sugar is converted into its inferior polymere: CeHi2Oe = 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 pro- duced is separated, purified and decomposed with an equivalent quantity of H2S04. It has also been obtained synthetically by oxidation of the propylglycol of Wurtz, which is a secondary glycol, a synthesis which indicates its constitution: ch3 ch3 CHOH + 02 = CHOH + H20 CHsOH 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° (266° F.) it loses water and is converted into dilac- tic acid, CcH10O5, and, when heated to 250° (432° F.), into lactid, C3H4O.. 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. The three lactic acids occur in animal nature, either free or in combination. Free lactic acid of fermentation occurs in the con- tents 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. Pathologi- cally in the blood in leucocytlnemia, pyaemia, puerperal fever, and after excessive muscular effort; in the fluids of ovarian cysts and transudations. In the urine it is abundant in phosphorus- 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 as sarcolactic acid. Normal, quies- cent muscle is neutral in reaction; but, when rigor mortis ap- pears, 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 decomposition 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 cir- culation, a fixed maximum of acid-producing capacity, which is OXIDS AND SULPHIDS OF CAKBON. 315 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. OXIDS AND SULPHIDS OF CARBON. As the saturated compound of carbon and oxygen is the anhy- drid of carbonic acid, the first of the series of acids just considered, it and its congeners may be appropriately treated of in this place. Carbon monoxid—Carbonous oxid—Carbonic oxid—CO—28—is formed: (1.) By burning C with a limited supply of air. (2.) By passing dry carbon dioxid over red-hot charcoal. (3.) By heating oxalic acid with HaSCh: C204H2 = H20+C0-(-C0a; and passing the gas through sodic hydrate to separate C02. (4.) By heating potassium ferrocyanid with HaSCh. It is a colorless, tasteless gas; sp. gr. 0.9678A; very' sparingly soluble in H20 and in alcohol. It burns in air with a blue flame and formation of carbon dioxid; it forms explosive mixtures with air and oxygen; it is oxi- dized to carbon dioxid by cold chromic acid. It is a valuable re- ducing agent, and is used for the reduction of metallic oxids at a red heat. Ainmoniacal solutions of the cuprous salts absorb it readily'. Being non-saturated, it unites readily with O to form C03, and with Cl to form C0C12, the latter a colorless, suffocating gas, known as phosgene, or carbonyl chlorid. Toxicology.—Carbon monoxid is an exceedingly poisonous gas, and is the chief toxic constituent of the gases given off from blast- fux-naces, from defective flues, and open coal or charcoal fires, and of illuminating gas. An atmosphere containing but a small proportion of this gas produces 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-fur- naces, the former containing 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 consist of a mixture of the two oxids of carbon, the dioxid predominating largely, especially when the combustion is most active. The following is the composition of an atmosphere produced byr burning charcoal in a confined space, and which proved rapidly fatal to a dog: oxy'gen, 19.19; nitrogen, 76.62; carbon dioxid, 4.61; carbon monoxid, 0.54; marsh-gas, 0.04. 316 MANUAL OF C1IEMISTKY. Obviously the deleterious effects of charcoal-fumes are more rap- idly 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 ad- dition may be made by a reduction of the dioxid, also formed, in passing over red-hot iron. Of late years cases of fatal poisoning by illuminating gas are of very frequent occurrence, caused either by accidental inhalation, by inexperienced persons blowing out the gas, or by suicides. The most actively poisonous ingredient of illuminating gas is CO, which exists in the ordinary coal-gas in the proportion of 4 to 7.5 per cent., and in water-gas, made by decomposing 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 form- ing with the blood-coloring matter a compound which is more stable than oxyhemoglobin, and thus causing asphyxia by de- stroying 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-matter thus rendered useless is supplied by new formation. The prog- nosis is very unfavorable when the amount of the gas inhaled has been at all considerable. The treatment usually followed, i.e., artificial respiration, and inhalation of O, 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 persistently bright red in color. When suitably diluted and examined with the spectroscope, it presents an absorption spec- trum (Fig. 36) of two bands similar to that of oxyhemoglobin (Fig. 16, 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 read- ily 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 oxyhemoglobin to the single- band spectrum of hemoglobin (Fig. 16, No. 12), while that of the CO compound remains unaltered, or only fades partially. OXIDS AND SULP1IIDS OF CAlihON. 317 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. A piece of gun-cotton upon which platinum-black has been dusted fires in air containing 2.5 in 1,000 of CO. For the method of determining CO in gaseous mixtures, see p. 324. Carbon dioxid—Carbonic anhydrid—Carbonic acid gas—C02—44 —is obtained: (1.) By burning C in air or O. (2.) By decom- posing a carbonate (marble=CaC03) by a mineral acid (HC1 di- luted with an equal volume of H20). At ordinary temperatures and pressures it is a colorless, suffo- cating gas; has an acidulous taste; sp. gr. 1.529xY; soluble in an equal volume of H20 at the ordinary pressure; much more solu- ble as the pressure increases. Soda water is a solution of carbonic Fig. 36. acid in H20 under increased pressure. When compressed 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 dioxid neither burns nor does it support combustion. When heated to 1,300° (2,370° F.), it is decomposed into CO and O. A similar decomposition 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 carbonate 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 carbon- ates 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. MANUAL OF CHEMISTRY. Atmospheric Carbon Dioxid.—Carbon dioxid is a constant con- stituent of atmospheric air in small and varying quantities; the mean amount in free country air being about 4 in 10,000. The variation in amount under different conditions is shown in the following table: Amount of Carbon Dioxid in Air. Collected at Parts in 10,000. Determined by Paris 3.190 Boussingault and Lewy. Andilly—twenty miles from Paris 2.969 Boussingaultand Lewy. Paris—Day 3.9 Boussingault. Night 4.2 Boussingault. Ocean—Day 5.42 Lewy. Night . 3.346 Lewy. Geneva 4.68 Saussure. 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 3.85 to 4.25 Saussure. January, frost 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. The expired air under ordinary conditions contains about 4.5 OXIDS AND SXJLPHIDS OF OAKBON. 319 per cent, by volume of COa, the proportion being greater the slower the respiration. (2.) Combustion.—The greater part of the atmospherie COa is a product of the oxidation of C in some form as a source of light and heat. In the following table are given the amounts of COa produced, and of air consumed, by different kinds of fuel and illuminating materials. In equal times, an ordinary gas-burner Fuel. Average amount burned in one hour. Average per- centage of Carbon dioxid pro- " duced by Air deoxidized by Heat units. Light in standard can- dles, 100. Carbon. Hydrogen. One volume in volumes. One part by wt. in parts by weight. In one hour. One volume in volumes. One kilo in cu- bic metres. In one hour. In kilos. In litres. In kilos. In litres. Hydrogen 100.00 2.39 26 89 Carbon to CO, 100.0 3.65 9.83 8080 Carbon to CO 100.0 4.93 2474 Carbon monoxid . 42 86 1.0 1 57 2.39 0.44 •_» }i i:j Marsh-gas 75.0 25.09 1.0 2.75 9.55 13.45 13063 Ethene 8ft 7*2 *2 0 3 14 14 3a 12 67 Coal-gas 140 litres 40.0 55.0 0.80 L67 0.221 112 7.14 1L04 1.293 1666 ll(XX) Crude petroleum.. 84.0 • 13.0 3.08 12.07 11775 Kerosene 15 gr. 87.0 13.0 3.17 0.048 25 12.12 0.236 182 11055 180 W ax 10 gr. 79.2 13.2 2.89 0.029 15 11.24 0.146 113 10496 100 Stearic acid 10 gr. 76.05 12. G8 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 GO 8.28 0.450 348 159 Wood (dry pine)... 39.10 4.90 1.43 5.16 3600 Wood charcoal... 85.0 3.10 8.36 7640 Peat 45 0 1.5 1 64 4 82 3000 Coke 87M 3 17 8 55 Anthracite 90 0 2 ft 3 29 9 22 Alcohol 52 17 13.04 1.90 8l6i 7183 Adult man 10 gr. C. 0.037 19 0.134 104 Combustion of Fuel, produces nearly six times as much COa, and consumes nearly ten times as much air as a man. The amount of air consumed by fuel is, for practical purposes, greater than that given in the 320 MANUAL OF CHEMISTRY. table, as the oxidation is never complete, the air in the chimney frequently containing ten per cent, of oxygen by volume. (3.) Fermentation.—Most fermentations, including putrefactive changes, are attended by the liberation of C02. Thus, alcoholic fermentation takes place according to the equation: C8H140, = 2C2H80 + 2COa 180 92 8» and consequently discharges into the air 88 parts by weight of C02 for every 92 parts of alcohol formed, or 384 litres of gas for every litre of absolute alcohol obtained. (4.) Tellural sources.—Volcanoes in activity discharge enormous quantities of C02, and, in volcanic countries, the same gas is thrown out abundantly 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 C02, known to miners as after-damp. Constancy of the amount of atmospheric carbon dioxid.—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 atmospheric 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, therefore, 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 discharging a volume of O about equal to that of the C02 absorbed. Air contaminated with excess of carbon dioxid, 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 pro- OXIDS AND SULPIIIDS OF CAltBON. 321 portion above 7 in 10,000 by volume, it is to be considered as con- taminated ; the seriousness of the contamination depending not only upon the amount of the increase, but also upon the source of the COa. If the gas be derived from fermentation, or from tellural or manufacturing sources, it is simply added to the other- wise 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 com- position of the air is much more seriously modified, as not only is there addition of a deleterious 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 cannot be based exclusively upon that quantity, as the deoxidation cannot be carried to completeness; indeed, when the proportion of C02 in air exceeds five per cent., it be- comes incapable of supporting life, while a much smaller quan- tity, 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 percentage of COa 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 CO-2 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 permissible maximum of impurity in an hour. Practically, owing to the imperfect closing of doors and win- dows, and to ventilation by chimneys, inhabited spaces are never hermetically closed, and a less quantity of air-supply than would be required in an air-tight space will suffice. 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 10x13x8 feet, and 13x15.6x9 feet. In calculating the space of dormitories to be occupied by sev- eral healthy people, the smallest air-space that should, under any circumstances, be allowed, is 12 cubic metres (=420 cubic feet) for each person. To determine the number of individuals that may sleep in a room, multiply 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 dormitory 40 feet long, 20 feet 322 MANUAL OF CHEMISTRY. wide, and 10 feet high, is fitted for the accommodation of 19 per- sons at most; for 40X20X10=8,000_and W/—19.05. As a rule, in places where many persons are congregated, it is necessary to resort to some scheme of ventilation by which a sufficient supply 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 is as shown in the table: Situation. Cubic metres. Cubic feet. Situation. Cubic metres. Cubic feet. Barracks (day-time) 35 1,336 Hospital wards (surgical). 170 6,004 Barracks (night-time) — ro 2,472 Contagious and lying-in.. 170 6.004 Workshops (mechanical). 70 2,472 Mines, metaliferous 150 5,297 35 1,236 170 6,004 Hospital wards 85 3,002 The amounts given are the smallest permissible, and should be exceeded wherever practicable. Lights.—Each cubic foot of illuminating-gas consumes in its combustion a quantity of 0 equal to that contained in 7.14 cubic feet of air, produces 0.8 cubic feet of C02, besides a large quantity of watery vapor, and less amounts of H2S04, S02, and sometimes CO; and an ordinary gas-burner consumes about three feet per hour. It is obvious, therefore, that a much larger quan- tity of pure air must be furnished to maintain the atmosphere of an apartment at the standard of 0.0 per 1,000 of C02, when the vitiation is produced b.y 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. In theatres the contamination of the air by the burning of gas should be entirely eliminated by placing the burners either under the dome ventilator, or in boxes which open to the air of the house only below the level of the burner, and which are in com- munication with a ventilating-shaft. When artificial illumination is obtained from lamps or candles, or from gas in small quantity and for a short time, the contami- nation 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 is that it con- sumes no O and produces no C02. Although, by the combustion of fuel, O is consumed and C02 produced, heating arrangements only become a source of vitiation of air when they are improperly constucted. Indeed, in the ma- OXIDS AND SULP1IIDS OF CAliBON. 323 jority of cases, if properly arranged, they are the means of venti- lation, 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 atmos- phere of pure C02 dies almost instantly, and without entrance of the gas into the lungs, death resulting from spasm of the glottis, and consequent apncea. When diluted with air, the action of CO2 varies according to its proportion, and according to the proportion of O present. When the proportion of 0 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. CO2 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 C03 be added to normal air, of course the relative quan- tity of O is slightly diminished, while its absolute quantity re- mains the same. This is the condition of affairs existing in nature when the gas is discharged into the air; under these circum- stances an addition of 10-15 per cent, of CO2 renders an air rap- idly poisonous, and one of 5-8 per cent, will cause the death of small animals more slowly. Even a less proportion than this may become fatal to an individual not habituated. In the higher states of dilution, CO2 produces immediate loss of muscular 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. If the COa 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, 6 per cent. C02, is much more rapidly fatal than one composed of 21 per cent. O, 59 per cent. N, 20 per cent. C02. With a correspond- ing reduction of O, 5 per cent, of C02 renders 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 CO2 consists in the inhalation of pure air (to which an excess of O may be added), aided, if necessary, by artificial respiration, the cold douche, gal- vanism, and friction. Detection of carbon dioxid and analysis of confined air.—Carbon dioxid, or air containing it, causes a white precipitate when caused to bubble through lime or baryta water. Normal air con- 324 MANUAL OF CHEMISTliY. tains 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 contin- ued 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 con- tained, burns readily in the presence of 8 per cent, of C02; is per- ceptibly dulled by 10 per cent.; is usually extinguished with 13 per cent.; always extinguished with 1G per cent. Its extinction is caused by a less proportion of C02, 4 per cent., if the quantity of O be at the same time diminished. Moreover, a contaminated atmosphere may not contain enough C02 to extinguish, or per- ceptibly dim the flame of a candle, and at the same time contain enough of the monoxid to render it fatally poisonous if inhaled. The presence of C02 in a gaseous mixture is determined by its absorption by a solution of potash; its quantity either by measur- ing the diminution in bulk of the gas, or by noting the increase in weight of an alkaline solution. Fig. 37. To determine the proportions of the various gases present in air the apparatus shown in Fig. 37 is used. A is an aspirator of known capacity, filled with water at the beginning of the opera- tion. It connects by a flexible tube from its upper part with an absorbing apparatus consisting of a, a U-shaped tube containing fragments of pumice-stone, moistened with H2S04; by the in- crease in weight of this tube the weight of watery vapor in the volume of air drawn through by the aspirator is determined; &, a Liebig’s bulb filled with a solution of potash; c, a U-tube filled with fragments of pumice moistened with H2S04; b and c are weighed together and their increase in weight is the weight of OXIDS AND SULP1IIDS OF CARBON. 325 COa 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 oxid of copper and heated to redness; e is a U-tube filled with pumice moistened with HaSCh; its increase in weight represents HaO obtained from de- composition of CH4. Every gram of increase in weight of e rep- resents 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 COa formed by oxidation of CO and CH4 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. Carbon disulphid—Bisulphid of carbon—Carbonei bisulphidum (XJ. 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 disagreeable 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 HaO; it refracts light strongly. It is highly inflammable, and burns with a bluish flame, giving off CO2 and SOa; its vapor forms highly explosive mixtures with air, which detonate on contact with a glass rod heated to 250° (482° F.). Its vapor forms a mixture with nitrogen dioxid, which, when ignited, burns with a brilliant flame, rich in actinic rays. There also exists a substance intermediate in composition be- tween CO2 and CS2, known as carbon oxysulphid, CSO, which is an inflammable, colorless gas, obtained by decomposing potas- sium sulphocyanate with dilute H2S04. 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 vul- canization of rubber, as well as others exposed to the vapor of the disulphid, are subject 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 disagreeable taste, cramps in the legs; the patient talks, laughs, sings, and weeps immoder- ately, and sometimes becomes violently delirious. In the second stage the patient becomes sad and sleepy, sensibility diminishes, sometimes to the extent of complete anesthesia, especially of the lower extremities, the headache becomes more intense, the ap- petite is greatly impaired, and there is general weakness of the limbs, which terminates in paralysis. 326 MANUAL OF CHEMISTRY. The only remedy which has been suggested is thorough venti- lation of the workshops, and abandonment of the trade at the first appearance of the symptoms. DIATOMIC AND DIBASIC ACIDS. Series CH2ji_„204. Oxalic acid C204H2 Malonic acid C3O4H4 Succinic acid C4O4H8 Deoxyglutanic acid ... .C604ll8 Adipic acid .C6O4H10 Pimelic acid C704Hi2 Suberic acid CsOiHn Azelaic acid C9O4H16 Sebacic acid CioChHig Roccellic acid C17O4H3!! They are derived from the primary glycols by complete oxida- tion ; 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 correspond- ing glycols, or from acids of the preceding series, by oxidation. COOH Oxalic acid— | —90—C20iH2,2Aq—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: sorrel, rhubarb, cinchona, oak, etc.; as a native ferrous oxalate; and in small quantity in human urine. It is prepared artificially by oxidizing sugar or starch by HN03, or by the action of an alkaline hydrate in fusion upon sawdust. The soluble alkaline oxalate obtained by the latter method is con- verted into the insoluble Ca or Pb salt, which is washed and de- composed by an equivalent quantity of H2S04 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 formates; and by the action of K or Na upon C02. It crystallizes in transparent prisms, containing 2Aq, which effloresce on exposure to air, and lose their Aq slowly but com- pletely 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 anhy- drous form, while a portion is decomposed; above 160° (320° F.) the decomposition is more extensive; II20, C02, CO, and formic acid are produced, while a portion of the acid is sublimed un- changed. It dissolves in 15.5 parts of water at 10° (50° F.); the presence of HN03 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 con- verted into C02 and H20, slowly by simple exposure to air, more DIATOMIC AND DIBASIC ACIDS. rapidly in the presence of platinum-black or of the salts of plati- num and gold; under the influence of sunlight; or when heated with HN03, manganese dioxid, chromic acid, Br, Cl, or hypo- chlorous acid. Its oxidation, when it is triturated dry with lead dioxid, is sufficiently active to heat the mass to redness. H3SO4, H3PO.t, and other dehydrating agents decompose it into H20, CO, and CO,. 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 HNOa and in NHuHO. The 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 HNOs, insoluble in acetic acid. Toxicology.—Although certain oxalates are constant constitu- ents of vegetable food and of the human body, the acid itself, as well as hydropotassic oxalate, is a violent poison when taken in- ternally, 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 i. of the solid acid, and recovery a dose of § i. 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, con- sists in the administration, first, of lime or magnesia, or a soluble salt of Ca or Mg suspended or dissolved in a small quantity of H,0 or mucilaginous fluid; afterward, if vomiting have not oc- curred 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 caution are to be ob- served. As in all cases in which a corrosive has been taken in- ternally, the use of the stomach-pump is to be avoided. The alkaline carbonates are of no value in cases of oxalic-acid poison- ing, as the oxalates which they form are soluble, and almost as poisonous as the acid itself. The ingestion of water, or the ad- ministration 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 dissolve, and thus favor the absorption of the poison. Analysis.—In fatal cases of poisoning by oxalic acid the con- tents of the stomach are sometimes strongly acid in reaction; more usually, owing to the administration of antidotes, neutral, or even alkaline. In a systematic analysis the poison is to be sought for in the residue of the portion examined for prussic acid 328 MANUAL OF CHEMISTRY. and phosphorus; or, if the examination for those substances be omitted, in the residue or final alkaline fluid of the process for alkaloids. 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 ex- tracted with alcohol, the alcoholic fluid evaporated, the residue redissolved in water (solution No. 1). The portion undissolved by alcohol is extracted with alcohol acidulated with hvdx-ochloric acid, the solution evaporated after filtration, the residue dissolved in water (solution 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 potassium 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 calicum oxalate. The stomach may contain small quantities of oxalates as normal constituents of certain foods. / rjoOTI Malonic acid—CH2(~qqjj—*s a Pro0 CHj—CO^ ch3. I >o CO 7 ch2—CO. (Jh2-CO/0 Acetic anhydrid, Glycolic anhydrid. Succinic anhydrid. AMINS OF THE GLYCOLS. Ethylenic Compound Ammonias—Diamins. These substances are derived from a double molecule of NHS, or of ammonium hydrate, by the substitution of the diatomic radicals of the glycols (hydrocarbons of the series CnHan.) for an equivalent number of H atoms. They are distinguished from the corresponding compounds of the radicals of the inonoatomic alcohols, the monamins, by the designation of diamins. When it is considered that in the formation of these substances double H atoms can be replaced by diatomic radicals to form primary, secondary, and tertiary amins : Ha) h2 h2 (C2H4)") h2 -n3 B, (C2H4)" ) (C,H4)' H2 (C2H4)") (C,h4)' In, (C3H4)" Double ammonia molecule. Ethylene amin Primary. Diethylene amin. Secondary. Triethylene amin. Tertiary. that others exist in which two univalent radicals replace a biva- lent radical; others, again, in which H atoms have been replaced by groups OH ; and finally, that similar compounds of P, As and Sb exist, it is not astonishing that the study of the vast number of substances, the possibility of whose existence is thus indicated, is still in its infancy. Some recently discovered alkaloids, produced during putrefac- tion (see Ptomains), are diamins ; and there is strong probability that further investigation will show some of the vegetable alka- loids, whose constitution is as yet unknown, to belong in this class. 332 MANUAL OF CHEMISTRY. Among the diamins are included the amidins, having the con- stitution It—C H,/ H,/ COOH CO\ H—N H/ COOH COOH Oximid. Secondary monamid. Oxamid. Primary diamid. Oxamic acid. Primary monamid. Oxalic acid. Acid. In the first of these, two H atoms of a single NH3 molecule are replaced by the bivalent radical of the acid; these are distin- guished as imids. Those of the second series are normally formed diamids. In the third series, the univalent remainder, left by the removal of OH from the acid, replaces an atom of H in one molecule of JnH3, and the resulting compound, still containing a group COOH, has the functions of a monobasic acid. Carbimid—CONII—43—is probably identical with cyanic acid (q.v.). (CO)" ) Carbamid—Urea— H2 v Na—60.—Urea does not occur in the H2) vegetable world. It exists principally in the urine of the mam- malia ; also in smaller quantity in the excrements of birds, fishes, and some reptiles ; in the mammalian blood, chyle, lymph, liver, spleen, lungs, brain, vitreous and aqueous humors, saliva, perspi- ration, bile, milk, amniotic and allantoic fluids, muscular tissue, and in serous fluids (see below). It is formed—(1.) As a product of the decomposition of uric acid, usually by oxidation : C6H4N4O3 + H20 + o = CON»H4 + c4h2n3o4 (2.) By the oxidation of oxarnid. Uric acid. Water. Oxygen. Urea. Alloxan. DIAMIDS. (3.) By the action of caustic potassa upon creatin : C4H9N303 + HaO = CON3H4 + C3HtN03 Creatin. Water Urea. Sarcosin. 4.) By the limited oxidation of albuminoid substances, by potassium permanganate, and during the processes of nutrition. (5.) By the action of carbon oxychlorid on dry ammonia. (6.) By the action of ammonium hydrate on ethyl carbonate at 180° (356° F.). (7.) By heating ammonium carbonate in sealed tubes to 130° (266° F.). (8.) By the slow evaporation of an aqueous solution of hydro- cyanic acid. (9.) By the molecular transformation of its isomerid, ammonium isocyanate: CN (CO)) 1 = H3 [■ Nj 0 (NH«) Ha It is obtained : (1.) From the urine.—Fresh urine is evaporated to the consist- ency of a syrup over the water-bath ; the residue is cooled and mixed with an equal volume of colorless HN03 of sp. gr. 1.42 ; the crystals are washed with a small quantity of cold H20, and dis- solved in hot Ha0 ; the solution is decolorized, so far as possible, without boiling, with animal charcoal, filtered, and neutralized with potassium carbonate ; the liquid is then concentrated over the water-bath, and decanted from the crystals of potassium nitrate which separate; then evaporated to dryness over the water-bath, and the residue extracted with strong, hot alcohol; the alcoholic solution, on evaporation, leaves the urea more or less colored by urinary pigment. (2.) By synthesis.—Urea is more readily obtained in a state of purity from potassium isocyanate. This is dissolved in cold HaO, and dry ammonium sulphate is added to the solution. Potassium sulphate crystallizes out, and is separated by decanting the liquid, which is then evaporated over the water-bath, fresh quantities of potassium sulphate crystallizing and being separated during the first part of the evaporation ; the dry residue is extracted with strong, hot alcohol ; this, on evaporation, leaves the urea, which, by a second crystallization from alcohol, is obtained pure. Urea crystallizes from its aqueous solution in long, flattened prisms, and by spontaneous evaporation of its alcoholic solution in quadratic prisms with octahedral ends. It is colorless and odorless ; has a cooling, bitterish taste, resembling that of salt- petre ; is neutral in reaction ; soluble in one part of H30 at 15° (59° F.), the solution being attended with diminution of tempera- Ammonium cyanate. Urea. 334 MANUAL OF CHEMISTRY. ture ; soluble in five parts of cold alcohol (sp. gr. 0.816) and in one part of boiling alcohol ; very sparingly soluble in ether. When its powder is mixed with that of certain salts, such as sodium sulphate, the Aq of the salt separates, and the mass be- comes soft or even liquid. When pure it is not deliquescent, but is slightly hygrometric. Fuses at 130° (266° F.). Heated a few degrees above 130° (266° F.) urea boils, giving off ammonia and ammonium carbonate, and leaves a residue of am- melid, CcH9N903. When heated to 150°-170° (302°-338° F.), it is decomposed, leaving a mixture of ammelid, cyanuric acid, and biuret : 8CON2H4 = 2COa + CsH9N903 + 7NH3 + HaO Urea. Carbon dioxid. Ammelid. Ammonia. Water. 3CON2H4 = C303N3H3 + 3NH3 Urea. 2CON3H4 = CaH6N30a + NIL Cyanuric acid. Ammonia. Urea. Biuret. Ammonia. If urea is maintained at 150°-170° (302°-338° F.) for some time, a dry, grayish mass remains, which consists principally of cya- nuric acid. In this reaction, the volatile products contain urea, not that that substance is volatile, but because a portion of the cyanuric acid and ammonia unite to regenerate urea by the re- verse action to that given above. Dilute aqueous solutions of urea are not decomposed by boil- ing ; but if the solution be concentrated, or the boiling prolonged for a long time, the urea is partially decomposed into COa and NH3. The same decomposition takes place more rapidly and completely when a solution of urea is heated under pressure to 140° (284° F.). A pure aqueous solution of urea is not altered by exposure to filtered air. If urine be allowed to stand, putre- factive changes take place under the influence of a peculiar, or- ganized ferment, or of a diastase-like body which is a constituent of normal urine. Chlorin decomposes urea with production of COa, N, and HC1. Solutions of the alkaline hypochlorites and hypobromites effect a similar decomposition in the presence of an excess of alkali, according to the equation : Urea. CONaEL + 3NaC10 = COa + 2HaO + Na + 3NaCl Sodium hypochlorite. Carbon dioxid. Water. Nitrogen. Sodium chlorid. Upon this decomposition are based the quantitative processes of Knop, Hiifner, Yvon, Davy, Leconte, etc. Nitrous acid, or HN03 charged with nitrous vapors, decomposes urea according to the equation : DIAMIDS. 335 CON2H4 -+- Na03 — COa + N4 -+• 2HaO (1) Urea. Nitrogen trioxid. Carbon dioxid. Nitrogen. Water. or the equation : 2CONaH4 + Na03 = C0«(NH4). + N4 + C0a (2) Urea. Nitrogen trioxid. Ammonium carbonate. Nitrogen. Carbon dioxid. If the mixture he made in the cold, of one molecule of nitrogen trioxid to two molecules of urea, the decomposition is that in- dicated by Equation 2. If, on the other hand, the trioxid be gradually added to the previously warmed urea solution in the same proportion, half the urea is decomposed while the remain- der is left unaltered, and, upon the addition of a further and sufficient quantity of the trioxid, all the urea is decomposed according to Equation 1. Upon this reaction are based the proc- esses of Gr61iant, Boymond, Draper, etc. When heated with mineral acids or alkalies, urea is decom- posed with formation of COa and NH3; if the decomposing agent be an acid, COa is given off, and an ammoniacal salt remains ; if an alkali, a carbonate of the alkaline metal remains, and NH3 is given off. Upon this decomposition are based the processes of Heintz and Ragsky, Bunsen, etc. Urea forms definite compounds, not only with acids, but also with certain oxids and salts. Of the compounds which it forms with acids, the most important are those with nitric and oxalic acids. Urea nitrate—C0NaH4,HN03—is formed as a white, crystalline mass when a concentrated solution of urea is treated, in the cold, with HN03. It is much less soluble in HaO than is urea, espe- cially in the presence of an excess of HN03. It decomposes the carbonates with liberation of urea. If a solution of urea nitrate be evaporated over the water-bath, it is decomposed, bubbles of gas being given off beyond a certain degree of concentration, and large crystals of urea, covered with smaller ones of urea nitrate, separate. Urea oxalate—2C0NaH4,HaCa04—separates as a fine, crystalline powder from mixed aqueous solutions of urea and oxalic acid of sufficient concentration. It is acid in taste and reaction, less soluble in cold Ha0 than the nitrate, and less soluble in the pres- ence of an excess of oxalic acid than in pure Ha0. Its solution may be evaporated at the temperature of the water-bath without suffering decomposition. Of the compounds of urea with oxids, the most interesting are those with mercuric oxid, three in number : a. CONaH4,2HgO is formed by gradually adding mercuric oxid to a solution of urea, heated to near its boiling-point; the fll- 336 MANUAL OF CHEMISTRY. tered liquid, on standing twenty-four hours, deposits crystalline crusts of the above composition. /3. CON2H4,3HgO is formed as a gelatinous pi’ecipitate when mercuric clilorid solution is added to a solution of urea containing potassium hydrate. y. CON2H4,4HgO is formed as a white, amorphous precipitate when a dilute solution of mercuric nitrate is gradually added to a dilute alkaline solution of urea, and the excess of acid neutralized from time to time. A yellow tinge in the precipitate indicates the formation of mercuric subnitrate after the urea has been all precipitated (Liebig’s process). Of the compounds of urea with salts, that with sodium chlorid is the only one of importance : C0N2H4,NaCl,H20.—It is obtained in prismatic crystals when solutions of equal molecules of urea and sodium chlorid are evaporated together. It is deliquescent and very soluble in water. Its solution, when mixed with solution of oxalic acid, only forms urea oxalate after long standing, or on evaporation. Urea is a constant constituent of normal mammalian blood and urine, and is the chief product of the oxidation of albuminoid substances which occur in the body; the bulk of the N assimi- lated from the food ultimately making its exit from the body in the form of urea in the urine. The determinations of the amount of urea in the blood and fluids other than the urine are, owing to imperfections in the processes of analysis, not as accurate as could be desired, the error being generally a minus one. Some of the more prominent are given in the following table : Quantity of Urea in Parts per 1,000 in Animal, Fluids OTHER THAN URINE. Normal blood—dog Munk. Normal blood—human 0.2 -0.4 Gamgee. Normal blood—human 0.16 Pickard. Normal blood—human 0.14-0.18 Gautier. Normal blood—human placental 0.28-0.62 Picard. Normal blood—human foetal 0.27 Picard. Blood of dog before nephrotomy 0.26-0.88 Gr^hant. Blood of dog three hours after nephro- tomy 0.45-0.93 Gr6hant. Blood of dog twenty-seven hours after nephrotomy 2.06-2.76 Gr6hant. Human blood in cholera 2.4 Voit. Human blood in cholera 3.6 Chalvet. Human blood in Bright’s 15.0 j ISgtom Lymph—dog 0.16 Wurtz. Lymph—cow 0.19 Wurtz. Chyle—cow 0.19 Wurtz. Milk 0.13 Picard. 1)1 AM IDS. Saliva 0.35 Picard. Bile 0.30 Picard. Fluid of ascites 0.15 Picard. Perspiration 0.38 Funke. Perspiration 0.88 Picard. Under normal conditions, the quantity of urea voided in twenty-four hours is subject to considerable variations, as is shown in the subjoined table : Amount of Urka in Human Urine—Normal. Parts per 1,000. Grams in total urine of 24 hours. Urine of sp. gr. 1009.2 .... 9.88 Millon. Urine of sp. gr. 1011.6 11.39 Millon. Urine of sp. gr. 1019.0 18.58 Bovmond. Urine of sp. gr. 1026.0 25.80 Millon. Urine of sp. gr. 1027.7 29.70 Millon. Urine of sp. gr. 1028.0 27.08 Boymond. Urine of sp. gr. 1029.0 31.77 Millon. Urine of adult male (average) 30.0 Berzelius. Urine of adult male (average) 28.052 Lecanu. Urine of adult male (average). ... 25-32 22-35 Neubauer. Urine of adult male (average) 32-43 Kerner. Urine of adult male (average) 23.3 35 Vogel. Urine of adult male, animal food 51-92 Franque. Urine of adult male, mixed food 36-38 Franque. Urineof adult male, vegetable food .... 24-28 Franque. Urine of adult male, non-nitrogen- ized food 16 Franque. Urineof old men, 84-86 years 8.11 Lecanu. Urineof adult female (average) 19.116 Lecanu. Urineof pregnant female 30-38 Quinquand. Urine of female 24 hours after de- livery 20-22 Quinquand. Urine of infant, first day ... 0.03-0.04 Quinquand. Urineof infant, fifth day 0.12-0.15 Quinquand. Urineof infant, eighth day 0.2 -0.28 Quinquand. Urineof infant, fifteenth day 0.3-0.04 Quinquand. Urineof child four years old 4.505 Lecanu. Urine of child eight years old 13.471 Lecanu. Urine of boy eighteen months old 8-12 Harley. Urine of girl eighteen months old .... 6-9 Harley. The variations are produced by : (1.) Age.—In new-born children the elimination of urea is insig- nificant. By growing children the amount voided is absolutely less than that discharged by adults, but, relatively to their weight, considerably greater ; thus, Harley gives the following amounts of urea in grams for each pound of body-weight in twenty four hours : Boy, eighteen months, 0.4; girl, eighteen months, 0.35; man, twenty-seven years, 0.25; woman, twenty- seven years, 0.20. During adult life the mean elimination of urea remains stationary, uidess modified by other causes than age. MANUAL OF CHEMISTRY. In old age the amount sinks to below the absolute quantity dis- charged by growing children. (2.) Sex.—At all periods of life females eliminate less urea than males. The proportion given by Beigel differs slightly from that of Harley, viz.: one kilo of male, 0.35 gram urea in twenty-four hours-; one kilo of female, 0.25 gram. During pregnancy females discharge more urea than males ; very shortly after de- livery the amount sinks to the normal, below which it passes during lactation. (3.) Food.—The quantity of urea eliminated is in direct propor- tion to the amount of N contained in the food. The ingestion of large quantities of watery drinks increases the amount, and a contrary effect is produced by tea, coffee, and alcohol. With in- sufficient food the excretion of urea is diminished, although not arrested, even in extreme starvation. (4.) Exercise.—The question whether the elimination of urea is increased during violent muscular exercise is one which has been the subject of many observations and of much discussion. An examination of the various results shows that, while the ex- cretion of urea is slightly gx-eater during violent exei’cise than during periods of rest, the increase is so insignificant in com- parison to the work done, and, in some instances, to the loss of body-weight, as to render the assumption that muscular force is the l'esult of the oxidation of the nitrogenized constituents of muscle improbable. (See Gaingee, ‘'Physiological Chemistry,” I., pp. 385-401, for a full review of the subject.) The percentage of urea in the urine of the same individual is not the same at different times of the day. The minimum hourly elimination is in the morning hours ; an increase begins immedi- ately after the principal meal, and reaches its height in about six hours, when a diminution sets in and progresses to the time of the next meal. Gorup-Besanez gives a curve representing the hourly variations in the elimination of urea, which, reduced to figures, gives the following : Hour. Urea in Grams. Hour. Urea in Grams- Hour. Urea in Grams. 8-9 A.M 1.5 4- 5 P.M 2.6 12-1 A.M 1.9 9-10 A.M.... 1.5 5- 6 P.M.. .. 3.1 1-2 A.M 1.9 10-11 A.M. . . 1.4 6- 7 P.M 2.8 2-3 A.M 1.9 11 A.M.-12 M. 1.3 7- 8 p.m 2.5 3-4 A.M 1.8 12 M.-l P.M.. 1.8 8- 9 P.M 2.3 4-5 A.M 1.6 1-2 P.M 1.9 9-10 p.m 2.0 5-6 A.M 1.6 2-8 P.M 2.1 10-11 P.M 2.0 6-7 A.M .... 1.6 3-4 P.M 2.3 11-12 P.M 2.3 7-8 A.M .... 1.5 DIAMIDS. 339 The total of which, however, represents a quantity above the normal. The absolute amount of urea eliminated in twenty-four hours is increased by the exhibition of diuretics, alkalies, colchicum, turpentine, rhubarb, alkaline silicates, and compounds of anti- mony, arsenic, and phosphorus. It is diminished by digitalis, caffein, potassium iodid, and lead acetate ; not sensibly affected by quinin. In acute febrile diseases both the relative and absolute amounts of urea eliminated augment, with some oscillations, until the fever is at its height. There is, however, no constant relation between the amount of urea eliminated and the body tempera- ture. During the period of defervescence, the amount of urea eliminated in twenty-four hours is diminished below the normal ; during convalescence it again sowly increases. If the malady terminate in death the diminution of urea is continuous to the end. In intermittent fever the amount of urea discharged is in- creased on the day of the fever and diminished during the inter- val. In cholera, during the algid stage, the elimination of urea by the kidneys is almost completely arrested, while the quantity in the blood is greatly increased. When the secretion of urine is again established, the excretion of urea is greatly increased (60-80 grams = 926-1235 grains a day), and the abundant perspiration is also rich in urea. In cardiac diseases, attended with respiratory difficulty, but without albuminuria, the elimination of urea is diminished and that of uric acid increased. In nephritis, attended with albuminuria, the elimination of urea at first remains nor- mal ; later it diminishes, and the urea, accumulating in the blood, has been considered by many as the cause of uraemic poi- soning. It appears more probable, however, that the symptoms of uraemia are due to the retention in the blood of alkaloidal poisons normally excreted in small amount. The quantity of urea in the urine is also diminished in all diseases attended with dropsical effusions ; but is increased when the dropsical fluid is reabsorbed. In true diabetes the amount of urea in the urine of twenty-four hours is greater than normal. In chronic diseases the elimination of urea is below the normal, owing to imperfect oxidation. To detect the presence of urea in a fluid, it is mixed with three to four volumes of alcohol, and filtered, after having stood sev- eral hours in the cold; the filtrate is evaporated on the water- bath, and the residue extracted with strong alcohol ; the filtered alcoholic fluid is evaporated, and the residue tested as follows : (1.) A small portion is heated in a dry test-tube to about 160° (320° F.), until the odor of ammonia is no longer observed; the residue is treated with a few drops of caustic potassa solution and 340 MANUAL OF CHEMISTRY. one drop of cupric sulphate solution. If urea be present, the biuret resulting from its decomposition by heat causes the solu- tion of the cupric oxid with a reddish-violet color. The same ap- pearance is produced in solutions containing peptone. (2.) A portion of the residue is dissolved in a drop or two of H20, and an equal quantity of colorless concentrated HNOs added ; if urea be present in sufficient quantity there appear white, shining, hexagonal or rhombic, crystalline plates or six- sided prisms of urea nitrate. (3.) A portion dissolved in water, as in (2), is treated with a solution of oxalic acid ; rhombic plates of urea oxalate crystallize. Determination of Quantity of Urea in Urine.—It must not be forgotten that, in all quantitative determinations of con- stituents of the urine, the question to be solved is not how much of that constituent is contained in a given quantity of urine, but how much of that substance the patient is discharging in a given time, usually twenty-four hours. QuantitatUe determinations are, therefore, in most cases, barren of useful results, unless the quantity of urine passed by the patient in twenty-four hours is knoAvn ; and, in vieAV of diurnal \rariations in elimination, unless the urine examined be a sample taken from the mixed urine of twenty-four hours. The process giving the most accurate results is that of Bunsen, in which the urea is decomposed into COa and NH3, the former of which is weighed as barium carbonate. Unfortunately, this process requires an expenditure of time and a degree of skill in manipulation which render its application possible only in a well-appointed laboratory. A process which is described in most text-books upon urinary analysis, and which is much used by physicians, is that of Lie- big. As this method is one, however, which contains more sources of error than any other, and as it can only be made to yield approximately correct results by a very careful elimination, as far as possible, of those defects, it is not one which is adapted to the use of the physician. Probably the most satisfactory process in the hands of the practitioner is that of Hiifner, based upon the reaction, to which attention was first called by Knop, of the alkaline liypobromites upon urea (p. 334); using, however. Dietrich’s apparatus, or the more simple modification suggested by Rumpf, in place of that of Hiifner. The apparatus (Fig. 38) consists of a burette of 30-50 c.c. capacity, immersed in a tall glass cylinder filled with water, and supported in such a way as to admit of being raised or low- ered at pleasure. The upper end of the burette communicates Avith the eArolution bottle a, which lias a capacity of 75 c.c., by means of a rubber tube. The reagent required is made as folloAvs : 27 c.c. of a solution of caustic soda, made by dissolving 100 grams NaHO in 250 c.c. H20, are brought into a glass-stoppered bottle, 2.5 c.c. bromin are added, the mixture shaken, and diluted with water to 150 c.c. The caustic soda solution may be kept in a glass-stoppered bottle 1)1 AM IDS. 341 whose stopper is well paraffined, but the mixture must be made up as required, a fact which, owing to the irritating character of the Br vapor, renders the use of this reagent in a physician’s office somewhat troublesome. The Br is best measured by a pipette of suitable size, having a compressible rubber ball at the upper end. To conduct a determination, about 20 c.c. of the hypobromite solution are placed in the bottle a; 5 c.c. of the urine to be exam- ined are placed in the short test- tube, which is then introduced into the position shown in the figure, care being had that no urine escapes. The cork with its fittings is then introduced, the pinch-cock b opened, and closed again when the level of liquid in the burette is the same as that in the cylinder. The decompos- ing vessel q is then inclined so that the urine and hypobromite solution mix; the decomposition begins at once, and the evolved X passes into the burette, which is raised from time to time so as to keep the external and internal levels of water about equal; the C02 formed is retained by the soda solution. In about an hour (the decomposition is usually complete in fifteen minutes, but it is well to wait an hour) the height is so ad- justed that the inner and outer levels of water are exactly even, and the graduation is read, while the standing of the barometer and thermometer are noted at the same time. In calculating the percentage of urea, from the volume of X ob- tained, it is essential that a cor- rection should be made for differ- ences of temperature and pressure, without which the result from an ordinary sample of urine may be vitiated by an error of ten per cent. If, however, the temperature and barometric pressure have been noted, the correction is readily made by the use of the table (see Appendix B. III.), computed by Dietrich, giving the weight of 1 c.c. X at different temperatures and pressures. In the square of the table in which the horizontal line of the observed temperature crosses the vertical line of the observed barometric pressure will be found the weight, in milligrams, of a c.c. of X; this, multiplied by the observed volume of X, gives the weight of X produced by the decomposition of the urea contained in 5 c.c. urine. But as 60 parts urea yield 28 parts X, the weight of X, multiplied by 2.14, gives the weight of urea in milligrams in Fig 38. 342 MANUAL OF CHEMISTRY. 5 c.c. urine. This quantity, multiplied by twice the amount of urine in 24 hours, and divided by 10,000, gives the amount of urea eliminated in 24 hours in grams. If the result be desired in grains the amount in grams is multiplied by 15.434. Example.—5 c.c. urine decomposed; barometer = 736 mm.; ther- mometer = 10°; burette reading before decomposition = 64.2; same after decomposition = 32.6 : c.c. N collected = 31.6. From the table 1 c.c. N at 10° and 736 mm BP weighs 1.1593. The patient passes 1500 c.c. urine in 24 hours : 31.6 X 1.1593 = 36.6339 = niilligr. N in 5 c.c. urine. 36.6339 X 2.14 = 78.3965 = niilligr. urea in 5 c.c. urine. 78.3965X 3000 IQ qqq = 23.519 = grains urea in M hours. 23.519 X 15.434 = 362.99 = grains urea in 24 hours. In using this process it is well to have the urea solution as near the strength of one per cent, as possible ; therefore if the urine be concentrated, it should be diluted. Even when carefully con- ducted, the process is not strictly accurate; creatinin and uric acid are also decomposed with liberation of N, thus causing a slight plus error : on the other hand, a minus error is caused by the fact that in the decomposition of urea by the hypobromite, the theoretical result is never obtained within about eight per cent, in urine. These errors may be rectified to a great extent by multiplying the result by 1.044. A process which does not yield as accurate results as the pre- ceding, but which is more easy of application, is that of Fowler, based upon the loss of sp. gr. of the urine after the decomposition of its urea by hypochlorite. To apply this method the sp. gr. of the urine is carefully determined, as well as that of the liq. sodae chlorinatte (Squibb’s). One volume of the urine is then mixed with exactly seven volumes of the 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 8. From the quotient so obtained the sp. gr. of the mixture after decomposi- tion 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 mix- ture 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 sam- ples of the urine are taken, one of 5 drops and one of 10 drops ; the latter is evaporated, at a low temperature, to the bulk of the former, and cooled ; to each, three drops of colorless HN03 are added. If crystals do not form within a few moments in the con- centrated sample, the quantity of urea is below the normal ; if COMPOUND UREAS. 343 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. The amorphous white ppt. caused by HN03 in albuminous urine must not be mistaken for the crystalline deposit of urea nitrate. 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 obtained from ammonium isocyanate, 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 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—C5HiN,0:iHo—168.—So far as yet 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 carniv- ora ; as a constituent of urinary calculi; and, very abundantly, in the excrement of serpents, tortoises, birds, mollusks, and insects, also in guano. It is present in very small quantity ip the blood of man, more abundantly in that of gouty patients and in that of birds. The so-called “chalk-stones ” deposited in the joints of gouty patients are composed of sodium urate. It also occurs in the spleen, lungs, liver, pancreas, brain, and muscular fluid. Although uric acid may be obtained from calculi, urine, and guano, the source from which it is most readily obtained 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 : the solution is boiled until all odor of NH3 has disappeared. Through the filtered solution 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 H20. The precipitated uric acid is washed and dried. 344 MANUAL OF CHEMISTRY. Uric acid, when pure, crystallizes in small, white, rhombic, rect- angular or hexagonal plates, or in rectangular prisms, or in den- dritic crystals of a hydrate, C6H4]Nr403,2H20. 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 dendritic groups, sometimes of considerable size. It is almost insoluble in II20. requiring for its solution 1900 parts of boiling H20 and 15,000 parts of cold H20 ; insoluble in alcohol and ether ; its aqueous solution is acid to test-paper; cold HC1 dissolves it more readily than H20, and on evaporation deposits it in rectangular plates. It is tasteless and odorless. When heated, it is decomposed without fusion or sublimation. Its constitution is not established with certainty, although it is very probably the diureid of tartronic acid. Heated in Cl it yields cyanuric acid and HC1. When Cl is passed for some time through HnO holding uric acid in suspension, alloxan, parabanic and ox- alic acids, and ammonium cyanate are formed. Similar decom- position is produced by Br and I. It is simply dissolved by HC1. It is dissolved by II2S04 ; from allot solution in which a deliques- cent, crystalline compound, C5H4jSu03, 4H2S04 is deposited ; it is partly decomposed by H2S04 at 140° (284° F.). It dissolves in cold HN03 with effervescence and formation of alloxan, alloxan- tin, and urea ; with hot HN03 parabanic acid is produced. So- lutions of the alkalies dissolve uric acid with formation of neu- tral urates. Uric acid is dibasic. Ammonium urates.—The neutral salt, C6H2N4Os(]STH4)2, is un- known. The acid salt, C5H3N403(NH4), 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. Sedi- ments of this salt are rust-yellow or pink in color, amorphous, or composed of globular masses, set with projecting points, or elongated dumb-bells, and are formed in alkaline urine. It is very sparingly soluble in H20 ; soluble in warm HC1, from which solution crystalline plates of uric acid are deposited. Potassium urates.—The neutral salt, C6H2N403K2, 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 H20 and in 35 parts of boiling I120. It is alkaline in taste, and absorbs C02 from the air. The acid salt, C6H3N403K, is formed as a granular (at first gelat- inous) precipitate when a solution of the neutral salt is treated with C02. It dissolves in 800 parts of cold H20 and in 80 parts of boiling H20. The occurrence of potassium urates in urinary sediments and calculi is very exceptional. COMPOUND UREAS. 345 Sodium urates.—The neutral salt, CsHaNiCbNaa, is formed under similar conditions as the corresponding potassium salt. It forms nodular masses, soluble in 77 parts of cold HaO and in 75 of boiling Ha0 ; it absorbs C0a from the air. The acid salt,C5H3N403Na, is formed when the neutral salt is treated with COa. It is soluble in 1200 parts of cold HaO and in 125 parts of boiling HaO. It occurs in urinary sediments and calculi, very rarely crystallized. The arthritic calculi of gouty patients are almost exclusively composed of this salt, frequently beautifully crystallized. Calcium urates.—The neutral salt, CsH2N403Ca, is obtained by dropping a solution of neutral potassium urate into a boiling so- lution of calcium chlorid until the precipitate is no longer redis- solved, and then boiling for an hour. A granular powder, solu- ble in 1500 parts of cold H30 and in 1440 parts of boiling HaO. The acid salt, (C6H3N403)aCa, is obtained by decomposing a boiling solution of acid potassium urate with calcium chlorid so- lution. It crystallizes in needles, soluble in 003 parts of cold H30 and in 276 parts of boiling HaO. It occurs occasionally in urinary sediments and calculi, and in “chalk-stones.” Lithium urates.—The acid salt, C6H3N403Li, is formed by dis- solving 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 partly 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. 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 albu- minoid substances—an oxidation intermediate in the production of urea ; and that consequently diseases in which there is an ex- cessive 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 proportion : Urea. Uric Acid. Proportion of Uric Acid to Urea, Animal food .. 71.5 1.25 57.2 Mixed food .. 37.0 0.76 48.7 Vegetable food .. 20.0 0.50 52.0 Non-nitrogenized food .. .. 16.0 0.34 47.0 346 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 twenty-four hours. With a strictly vegetable diet the elimination of twenty-four 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 increased in gout. Uric acid may be recognized by its crystalline form and by the murexid test. The substance is moistened with HN03, which is evaporated nearly to dryness at a low temperature ; the cooled residue is then moistened with ammonium hydrate solution. If uric acid be present, a yellow residue—sometimes pink or red when the uric acid was abundant—remains after the evaporation of the HN03, 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 con- sistency of a jelly ; the fibril is then examined microscopically. If the blood contain uric acid in abnormal proportion, the thread will have attached to it crystals of uric acid. The best method for the determination of the quantity of uric acid in urine is the following: 250 c.c. of the filtered urine are acidulated with 10 c.c. of HC1, and the mixture set aside for twenty-four hours in a cool place. A small filter is washed, first with dilute HC1 and then with H20, dried at 100" (212° F.), and weighed. At the end of twenty-four 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 H20 is to be used in this part of the process, the filtered urine being made use of 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, 0m*r-.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. COMPOUND UREAS. 347 XJreids derived from Uric Acid.—These substances are quite numerous, and are divisible into ureids, diureids, triureids, and uraemic acids, according 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 retain a group CQOH. Some of these substances require a brief mention : (CO) ' ) Oxalylurea—Parabanic acid—(C2Oa) ” - N2—114—is urea in which H9 ) two atoms of H have been replaced by the bivalent radical (C2O3)” of oxalic acid. It is obtained by oxidizing uric acid or alloxan by hot HNO3. Allantoin—C|HfiN,03—130—occurs in the allantoic 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 HaO, with lead dioxid. It crystallizes in small, tasteless, neutral, colorless prisms; sparingly soluble in cold HaO, readily soluble in warm HaO. Heated with alkalies it yields oxalic acid and NH3; and with dilute acids, allanturic acid, C;,H,N.Oi. Allantoin has been obtained synthetically by heating together glyoxylic acid and tirea. Mesoxalylurea—Alloxan—C4H2N2O4—142—is a product of the limited oxidation of uric acid. It has been found in the intestinal mucus in a case of diarrhoea. It forms colorless crystals, readily soluble in HaO. It gradually turns red in air, and stains the skin red. Oxaluric acid——132—occurs in its ammonium salt, as a normal constituent, in small quantity, in human urine. It may be obtained 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 solu- ble needles. Its ready conversion into urea and oxalic acid and its formation from oxalylurea, itself 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 nitrogenous con- stituents of the body. Dialuric acid—Oxybarbituric acAd—C,H,N ,Oi—a dibasic acid produced by reduction of alloxan. Alloxantin—CPH|N407—is a substance crystallizing in small, brilliant, very sparingly soluble prisms, produced by the action of reducing agents upon alloxan, whose action is less powerful than that required to convert alloxan into dialuric acid. Murexid — Ammonium purpurate—C,H4(NH4)N60,—is pro- 348 MANUAL OF CHEMISTliV. duced by oxidation of uric acid, of alloxan, and of a number of other derivatives of uric acid with subsequent contact of ammo- nium hydrate. It is supposed to be the ammonium salt of a hypothetical and non-isolated acid. The ammonium salt is of a brilliant, but evanescent purple color. (See Murexid test for uric acid, p. 846.) Hydurilic acid—ChH,,N,Of>—is produced as a yellowish, crystal- line, sparingly soluble powder by heating together glycerin and dialuric acid. It is a strong dibasic acid. Violuric acid—C.HnN^O,—is produced, along with alloxan, by the action of nitric acid upon hydurilic acid. It forms small, readily soluble, octahedral crystals. It is a strong monobasic acid; whose salts are brilliantly colored. /s TT Carbamic acid—^\cooH' itself is unknown, but many of its salts and ethers have been obtained. The salts are much less stable than the ethers. Of the latter, one has become of some medical importance, not only in itself but also in certain of its derivatives. /'U Ethyl carbamate—Urethan—N qqq q jj —is formed (1) by the action of cyanogen chlorid on alcohol; (2) by the action of alcohol upon urea nitrate underpressure at 120 -180° (248 -266° F.); (8) by the action of ethylearbonic ether, C03(C2Hr,)2, on alcohol. It forms thin, large, transparent, crystalline plates, fusible at about 50° (122° F.); boils at 180° (356° F.), very soluble in alcohol and in water. Chloral-urethan—Uralium—Somnal—C;H, ,C10 N (?)—is a prod- uct obtained by the action of chloral upon urethan in the pres- ence of ethylic alcohol. It is a very deliquescent, crystallizable solid, readily soluble in alcohol; decomposed by hot H20 into chloral and urethan. It is questionable whether this is a definite compound or a mere mixture. TRIATOMIC ALCOHOLS. These substances are known as glycerins or glycerols. Their relation to the monoatoniic and diatomic alcohols is shown by the following formulae : Series CnH»+!03. CH3 I ch2 ch3 ch3 ch2 I ch2oh ch2oh I ch2 I ch2oh ch2oh I CHOH I ch2oh Propane. Propyl alcohol. Propyl glycol. Glycerin. THIATOMIC ALCOHOLS. 349 They are obtained by the saponification of their ethers, either those existing in nature or those produced artificially. They combine with acids to form three series of ethers, known as monoglycerids, diglycerids, and triglycerids, formed by the combination of one molecule of the alcohol with one, two, or three molecules of a monobasic acid. Glycerin—Glycerol—Propenyl Alcohol—Glycarinum (TJ. S.)— C,H,(OH) 3—92—was first obtained as a secondary product in the manufacture of lead plaster ; it is now produced 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 king- doms. It has been obtained by partial synthesis, by heating for some time a mixture of allyl tribromid, 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 the distillation of the product in a current of superheated steam—is free from the im- purities which contaminated 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 sometimes under imperfectly understood conditions, forming small, white needles of sp. gr. 1.268, and fusible between 7° 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 un- altered at 275°-280° (527°-586° F.), but the greater part is decom- posed into acrolein, acetic acid, carbon dioxid, and combustible gases. It may be distilled unchanged in a current of superheated steam between 285° and 315° (545°-599J F.), and distils under ordi- nary conditions when perfectly pure. Concentrated glycerin, wdien heated to 150° (302° F.) ignites and burns without odor and without leaving a residue, and with a pale blue flame. It may also be burnt from a short wick. Glycerin is readily oxidized, yielding different products with different degrees of oxidation. Platinum-black oxidizes it, with formation, finally, of H20 and C02. Oxidized by manganese 350 MANUAL OF CHEMISTRY. dioxid and H2S04, it yields C02 and formic acid. If a layer of glycerin diluted with an equal volume of H20 be floated on the surface of HN03 of sp. gr. 1.5, a mixture of several acids is formed: oxalic, C204H2; glyceric, C3H604 ; formic, CH202; glycollic, C2H403 ; glyoxylic, C3H404; and tartaric, C4H6Oe. When glycerin is heated with potassium hydrate, a mixture of potassium acetate and formiate is produced. When glycerin, diluted with 20 volumes of H20, is heated with Br ; C02, bromo- form, glyceric acid, and HBr are produced. Phosphoric anhy- drid removes the elements of H2G from glycerin, with formation of acrolein (see p. 303). A similar action is effected by heating with H2S04, or with potassium hydrosulphate. Heated with oxalic acid, glycerin yields C02 and formic acid. The presence of glycerin in a liquid may be detected as follows : Add NaHO to feebly alkaline reaction, and dip into it a loop of Pt wire holding a borax bead ; then heat the bead in the blow- pipe flame, which is colored green if the liquid contain of glycerin. The glycerin used for medicinal purposes should respond to the following 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 nitrate ; (4) it should not be colored by H2S ; (5) when dissolved in its own weight of alcohol, containing one per cent, of H2S04, the solution should be clear ; (6) when mixed with an equal volume H2S04, of sp. gr. 1.83, it should form a limpid, brownish mixture, but should not give off gas. ACIDS DERIVABLE FROM THE GLYCERINS. Three series of acids are derivable from the glycerins by sub- stitution of O for Ha in the group CHaOH : ch2oh CHOH I CH2OH CHsOH CHOH I COOH COOH CHOH I COOH ch2,cooh I ch2,cooh oh2,cooh Glycerin. Glyceric acid. Tartronic acid. Tricarballylic acid, The terms of each series are triatomic ; those of the glyceric series are monobasic, those of the tartronic series are dibasic, and those of the tricarballylic series are tribasic. Malic acid—C4Hr,06—134—is the second term of the tartronic series, and is therefore dibasic. It exists in the vegetable king- dom ; either free or combined with K. Na, Ca, Mg. or organic bases ; principally in fruits, such as apples, cherries, etc. ; accom- panied by citrates and tartrates. ETHERS OF GLYCERIN. 351 It crystallizes in brilliant, prismatic needles ; odorless ; acid in taste ; fusible at 100° (212° F.); loses HaO at 140° (284° F.) ; deli- quescent ; very soluble in HaO and in alcohol. Heated to 175°- 180° (347°-356° F.), it is decomposed into HaO and maleic acid, C4H,Oi. The malates are oxidized to carbonates in the body. TRIBASIC UNSATURATED ACIDS. Aconitic Acid—CoH3(COOH)3—exists in its Ca salt in the differ- ent species of aconitum and of equisetum. It forms white, crystalline crusts, or by slow crystallization white plates or prisms ; odorless ; sour ; soluble in water, alcohol and ether ; fuses at 186° (366°.8 F.). Its salts are soluble and crystalline. It is decomposed by heat into itaconic acid and C02. Chelidonic Acid—CiH(COOH)3—crystallizes in sparingly soluble needles with 1 Aq. Exists in Chelidonium majus. Meconic Acid—CiHO(COOH)s 3Aq—is peculiar to opium, in which it exists in combination with a part, at least, of the alka- loids. It crystallizes in small prismatic needles ; acid and astrin- gent in taste ; loses its Aq at 120° (248° F.) ; quite soluble in water ; soluble in alcohol ; sparingly soluble in ether. With ferric chlorid it forms a blood-red color, which is not dis- charged by dilute acids or by mercuric chlorid ; but is discharged by stannous chlorid and by the alkaline hypochlorites. ETHERS OF GLYCERIN. Glycerids. As glycerin is a triatomic alcohol, it contains three oxhydryl groups which may be removed, combining with H from an acid to form H20, and leaving a univalent, bivalent, or trivalent re- mainder, which may replace the H of monobasic acids to form three series of ethers. As, further, the OH groups differ from each other in that two of them are contained in the primary group CHaOH, the other in the secondary group CHOH, there exist two isomeres of each mono- and di-glycerid : ch2oh I CHOH I ch2oh CH2—O—C2H30 CHOH I ch2oh ch2—o—c2h3o I CH—O—C2H30 I ch2oh CHa—O—C2H30 I CH—O—C2H30 C H a—O—C* H 3 O Glycerin. Manoacetin. Diacetin. Triacetin. Of the many substances of this class, only a few, principally those entering into the composition of the neutral fats, require consideration here. 352 MANUAL OF CHEMISTRY. Tributyrin—C:iHo(0,CiH70)3—302—exists in 'butter. It may also be obtained by heating glycerin with butyric acid and H2SO4. It is a pungent liquid, very prone to decomposition, with liberation of butyric acid. Trivalerin—C3Hf>(0,Cr,Hu0)3—344—exists in the oil of some mari- time mammalia, and is identical with the pliocenin of Clievreul. Tricaproin—CyHs^OjCcHuOla—386—Tricaprylin—C3H:,(0,Ct.H160)3 —470—and Tricaprin—C;iH5(0,CiuH1.j0)3—554—exist in small quan- tities in milk, butter, and cocoa-butter. Tnpalmitin—C3H5(0,CicHai0)3—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 spar- ingly soluble in alcohol, even when boiling ; very soluble in ether. It fuses at 50° (122° F.) and solidifies aga'n at 46° (114°.8 F.). Tiimargarin—C3H5(0,CnH330)3—848—has probably been ob- tained 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 constituent of animal fats is a mixture of tripalmitin and tristearin. Tristearin—C3H;,(0,Cn.H360)3—890—is the most abundant con- stituent of the solid fatty substances. It is prepared in large quantities as an industrial product in the manufacture of stearin candles, etc., but is obtained in a state of purity only with great difficulty. In as pure a form as readily obtainable, it forms a hard, brittle, crystalline 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—C3H5(0.ClbH330)3—884—exists in varying quantity in all fats, and is the predominant constituent of those which are liquid at ordinary 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 ex- pressing. It is a colorless, odorless, tasteless oil; soluble in alcohol and ether, insoluble in water; sp. gr. 0.92. Trinitro-glycerin—Nitro-glycerin—C3H:i(0N02)3—227—used as an explosive, both pure and mixed with other substances, in dyna- mite, giant powder, etc., is obtained by the combined action of H2SO4 and HNO3 upon glycerin. Fuming HNO3 is mixed with twice its weight of II2SO4 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 con- stant stirring, while the vessel is kept well cooled ; after five minutes the whole is thrown into 5-6 volumes of cold water ; the NEUTRAL OILS AND FATS. 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. gr. 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 decomposition ; at 185’ <365’ F.) it boils, giving off nitrous fumes; at 217° (422°.6 F.) it explodes violently; if quickly heated to 257° (494 .0 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 COa ; N ; vapor of HaO, 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 diatoma- ceous earth, in which form it is known as dynamite, etc. When taken internally, nitro-glycerin is an active poison, pro- ducing effects somewhat similar to those of strychnin ; in drop- doses, diluted, it causes violent headache, fever, intestinal pain, and nervous symptoms. It has been latterly used as a therapeu- tic 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, tri- stearin, and triolein, with small quantities of other glycerids, coloring and odorous principles, which are obtained from animal and vegetable bodies. The oils are fluid at ordinary tempera- tures, the solid glycerids being in solution in an excess of the liquid triolein. The fats, owing to a less proportion of the liquid glycerid, are solid or semi-solid at the ordinary temperature 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 H20, upon which they float; combustible, burning with a luminous flame. When rubbed upon paper they render it translucent. When heated with the caustic alkalies, or in a current of super- heated 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.). 354 MANUAL OF CHEMISTRY. Most of the fats and many of the oils, when exposed to the air, absorb O, 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 decom- position. Some of them, by oxidation on contact with the air, become thick, hard and dry, forming a kind of varnish over sur- faces upon which they are spread; these are designated 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 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 separate 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. Good 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 dis- tinguish them from other vegetable products having an oily ap- pearance, 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 dis- tillation, 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 liberated by spon- taneous decomposition. Rape-seed and colza oils, produced from various species of Brassica, are yellow, limpid oils having a strong odor and dis- agreeable 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 contains, besides the gly- cerids of oleic, crotonic and fatty acids, about four per cent, of a peculiar principle called crotonol, to which the oil owes its vesi- NEUTRAL OILS AND FATS. 355 eating properties. It also contains an alkaloid-like substance, also existing in castor-oil, called ricinin. 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 resembling olive-oil, in place of which it is frequently used for culinary purposes, intentionally or otherwise. It is readily sapon- ifiable, 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 sub- stituted. % Almond-oil—Oleum amygdalae expressum (U. S.)—Oleum amyg- dalae (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 yel- low 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 HN03 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 HN03 and H3SO.1. 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 liberated fatty acids dissolved in 50 c.c. of strong alcohol; the solution precipi- tated with lead acetate; the precipitate washed with ether; the residue decomposed with hot dilute HC1; the oily layer separated and extracted with strong alcohol; the alcoholic fluid, on evapo- ration, yields crystals of arachaic acid, if the oil contains peanut- oil. The most usual adulteration is with cotton-seed-oil, which may be detected, if more than 5% be present, as follows: 10 c.c. each of the oil and of ethylic ether are agitated in a test-tube; add 5 c.c. strong solution of neutral lead acetate, and then 5 c.c. ammonium hydrate solution, and agitate again. In the presence of cotton-seed-oil an orange-red color is produced, particularly in the upper layer. Cocoa-butter—Oleum theobromae (U. S., Br.)—is, at ordinary temperatures, 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 rancid. The most reliable test of its 356 MANUAL OF CJIEMISTliY. purity is its fusing-point, which should not be much below 33° (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 partially, replaced by linoleic acid, whose pres- ence causes the oil, on exposure to air, to absorb oxygen and be- come 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 ex- pression 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 sep- arates from it a crystalline solid, fusible at 66° (158°.8 F.), ricino- lamid. Hot HN03 attacks it energetically, and finally converts it into suberic acid. Whale-oil—Train-oil—obtained by trying out the fat or blub- ber of the “ right whale ” and of other species of balance. It is of sp. gr. 0.924 at 15° (59° F.); brownish in color; becomes solid at about 0°; has a very nauseous taste and odor. It is colored yel- low by H2S04; 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 15° (59° F.)=0.916. It is bleached, not colored, by chlorin. 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 H2S04, but is colored brown by a mixture of H2S04 and HN03. 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 H2S04. 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 oleomargarine. Cod-liver-oil—Oleum morrhuee (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 vari- eties of this oil: (a) Brown.—Dark brown, with greenish reflec- tions; has a disagreeable, irritating taste; faintly acid; does not solidify at —13° (8°.6 F.). (b) Bale brown.—Of the color of Sherry NEUTRAL OILS AND FA1S. wine; Las 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 H3SCL, gives a bluish-violet aureole, which gradually changes to crimson, and later to brown. A drop of fuming HN03 dropped into the oil is surrounded by a pink aureole if the oil be pure. If the oil be 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 rosanilin. Cod-liver-oil contains, besides the glycerids 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 com- position; small quantities of bromin and iodin, probably in the form of organic compounds; a peculiar fatty acid called gadinic acid, which solidifies at 60° (140° F.); and a brown substance called gaduin or gadinin. It also contains two alkaloids: Asellin, C3,H32N4, and morrhuin, CiBHS7N3. 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 glycerids of stearic, palmitic, and oleic acids exist, in health, in nearly all parts of the body; in the fluids in solution or in suspension, in the form of minute oil-globules; incorporated in the solid or semi-solid tissues, or deposited in col- lections in certain locations, as under the skin, enclosed in cells of connective tissue. 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 con- siderably from tha't proportion in conditions not, strictly speak- ing, pathological. The approximate quantities of fat in 100 parts of the various tissues and fluids, in health, are the following: Urine ? Perspiration 0.001 Yitreous 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 Spinal cord 23.6 Fat-tissue 82.7 Marrow 96.0 358 MANUAL OF CIIEMISTKY. 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 inhabitants of cold climates than in those of hot countries. In wasting from disease and from starvation the fats are rapidly absorbed, 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 individuals amounts to a pathological condition, fats may accumulate in certain tissues as a result of morbid changes. This accumulation may be due either to degeneration or to infiltration. In the former case, as when muscular tissue degenerates in con- sequence of long disuse, the natural tissue disappears and is re- placed by fat; in the latter case, as in fatty infiltration of the heart, oil-globules are deposited between the natural morpholog- ical elements, whose change, however, may subsequently take place by true fatty degeneration, due to pressure. 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 saccha- rine constituents 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 mem- branes in the stomach, until they reach the duodenum. Here, under the influence of the pancreatic juice, the major part is con- verted into a fine emulsion, in which form it is absorbed by the lacteals. A smaller portion is saponified, and the products of the saponification, free fatty acids, soaps, and glycerin, subsequently absorbed by lacteals and blood-vessels. The service of the fats in the economy is undoubtedly as a pro- ducer 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 heces; a small quantity distributed over the surface in the perspiration and sebaceous 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 agitation, and more or less salted to insure its keeping. It consists of the glycerids of stearic, palmitic, oleic, butyric, capric, caprylic, and caproic acids, with a small amount of coloring mat- NEUTRAL OILS AND FATS. 359 ter, more or less w'ater and salt, and casein. Good, natural but- ter 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, ani- mal fats other than those of butter, and artificial coloring mat- ters. 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 deter- mine the presence 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 chlorin in the ash by the nitrate of silver method (see Sodium chlorid). Roughly, the weight of the ash may be taken as salt. Starch is detected by spreading out a thin layer of butter, adding solution of iodin, and examining under the microscope for purple spots. The detection of foreign fats in butter, formerly a most unsat- isfactory problem to the analyst, has now become one which may be answered with great certainty. All of the chemical processes used are based upon a peculiar difference in the composition of butter-fat from other animal and vegetable fats and oils. When butter-fat is saponified, it yields from 5 to 8 per cent, of butyric acid and its near homologues, which are soluble in H20, and may be distilled without suffering decomposition, and from 85.5 to 87.5 of stearic, palmitic, and oleic acids, which are neither soluble in water nor capable of being distilled. The other fats and oils, when saponified, yield mere traces of the volatile or soluble fatty acids, and much larger quantities (95.3 to 95.7 per cent.) of insol- uble acids. These variations are utilized directly in some proc- esses, such as those of Hehner and Reichert, in which the percent- age of fixed and volatile acids are directly determined. In other processes, such as those of Koettstorfer and Hiibl, advantage is taken of the different neutralizing power of the two groups of acids. Thus, as butyric acid, C4H802, and stearic acid, CigHseCL, are each capable of neutralizing KHO, molecule for molecule, it follows that their neutralizing power is in proportion to their molecular weights, and that 56 parts KHO will require for neu- tralization 88 parts of butyric acid, or 284 parts of stearic acid. For descriptions of processes the student is referred to Allen, “Commercial Organic Analysis,” 2d ed., II., pp. 145-160. Methods for detecting admixture of foreign fats by physical means are unreliable. One of the best, which may be of service for preliminary testing, 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 butter 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 im- mersed in water at 153 (59° F.) until the fat has solidified. The 360 MANUAL OF CHEMISTRY. test-tube is then arranged as shown in Fig. 39, 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 “ sink- ing-point.” The sinking-point of pure butter is 34°.3 to 36°.3 (93°.7-97°.3 F.), that of oleomargarine is lower, that of butter adulterated with other fats is higher. “Oleomargarine” is a product made in im- itation of butter, which it resembles very closely in color, taste, odor, and general ap- pearance. Under the original patent, it is made from beef-fat, which is hashed, steamed, and subjected to pressure at a carefully regu- lated temperature. Under this treatment it is separated into two fatty products, one a white solid, “ stearine,” the other a faiptly yellow oil, “oleo-oil.” This oil is then mixed with milk, the mixture colored and churned. The subse- quent treatment of the product is the same as that of butter. “ Butterine,” “ suine,” etc., are products made, by modifications of the above process, from beef or mutton tallow, lard, and cot- ton-seed-oil. Butter is frequently, and oleomargarine is always, colored with some foreign pigment, “ butter color,” which is usually a prepara- tion of annoto. 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 saponification 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 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 adding, 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 adher- ing water, fused, and cast into moulds. White Castile soap—Sapo(TJ. S.), Sapo durus (Br.)—is a Isa soap made from olive-oil; strongly alkaline, hard, not greasy, very soluble ; contains 21 per cent. H20. Sapo mollis (Br.) is a K soap r ig- 39. LECITHINS—NERVE-TISSUE. 361 made from olive-oil, and contains an excess of alkali and glycerin. Yellow soap is made from tallow or other animal fat, and con- tains about £ its weight of rosin. Emplastrum plumbi (U. 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 forma- tion of an insoluble soap; and in the same way by most of the metallic salts. LECITHINS—NERVE-TISSUE. Lecithin—is a substance first obtained from the yolk of hens’ eggs, and subsequently found to exist in brain-tissue, particularly the gray substance, nerve-tissue, semen, blood-corpuscles, blood- serum, milk, bile, and other animal tissues and fluids. As obtained from brain-tissue lecithin is a colorless or faintly yellowish, imperfectly crystalline solid, or sometimes of a waxy consistency. It is very hygroscopic. It does not dissolve in HaO, in which, however, it swells up and forms a mass like starch- paste. It dissolves in alcohol or ether, very sparingly in the cold, but readily under the influence of heat. It dissolves in chloro- form and in benzol. Lecithin is very prone to decomposition, particularly at slightly elevated temperatures. Its chlorid com- bines with PtCl4 to form an insoluble yellowish chloroplatinate. When an alcoholic solution of lecithin is brought into contact with hot solution of barium hydrate it yields barium glycero- phosphate, barium stearate, and cholin (see p. 276). This decom- position indicates the constitution of lecithin and its relations to the fats. Glycerophosphoric acid is phosphoric acid in which an atom of hydrogen has been replaced by the univalent remainder CHiOH—CHOH—CHa—left by the removal of OH from glycerin; /OH 0=P—OH \0—CH2—CHOH—CHaOH. In lecithin the remaining oxhydryl groups of the glycerin re- mainder are removed by union with the basic hydrogen of two molecules of stearic acid, and one of the two remaining basic hydrogen atoms of the phosphoric acid is displaced by cholin. It is obvious that the number of lecithins is not limited to one, but that many may exist, and probably do, into whose composition any one, or any combination of two, of the acids of the same series as stearic acid may enter 3)3 /O—N CHj—CH2—OH 0=P—O—H \0—CH2—CH(C18H3603)—CH2(C18H 35 02). Distearyl-lecithin. 362 MANUAL OF CHEMISTRY. Nerve-tissue, which is exceedingly complex in its chemical com- position, and whose chemistry is still in a most rudimentary con- dition, seems to contain similar constituents in its different parts, which differ, however, materially in their quantitative composi- tion. The following substances have been obtained from cerebral tissue: Mineral Substances. Products of Decomposition. Water. CHycerophosphoric acid. Phosphates of Na, K, Ca, Mg. Oleophosphoric acid. Ferric oxid. Volatile fatty acids. Silicic oxid. Lactates. Traces of sulphates, clilorids, Hypoxanthin. and fluorids. Xanthin. Creatin. Albuminoids. Substance related to myosin. Soluble albuminoid, coagulable at 75° (107*° F.). Casein (?). Organic Substances. Elastin. Lecithin. Neurokeratin. Fats (?). Nuclein. Inosite. Cerebrin. Cholesterin. The composition of white and gray matter differs quantita- tively, as shown below: Albuminoids Gray Matter. . 55.37 White Matter. 24.72 Lecithin , 17.24 9.90 Cholesterin and fats . 18.68 51.91 Cerebrin 0.53 9.55 Extractive matters, insoluble in ether... , 6.71 3.34 Salts 1.46 0.57 Cerebrin is a substance deposited in the crystalline form from hot ethero-alcoholic extracts of brain-tissue. It is white, very light, odorless, and tasteless; insoluble in water or in cold alcohol or ether. Its solutions are neutral. It does not contain phos- phorus. The substance known as protagon, described by Liebreich as having been obtained from brain-tissue, would seem to exist there notably in the white substance of Schwann. It appears to be a compound formed by the union of lecithin with cerebrin. Neurokeratin is a substance occurring principally in the gray matter, which is insoluble in all solvents, and is not acted upon by digestive liquids. DIAMIDS OF THE TART FUNIC SERIES. 363 DIAMIDS OF THE TARTRONIC SERIES. Amids of malic acid.—Malic acid may yield five amids, whose relations to the acid and to each other are shown by the following formulae; CO, OH CH,OH I ch3 CO,OH Malic acid. CO,OH CH.NH, I CHa CO,OH Aspartic acid. CO,NHa CH,OH I CH3 I CO,OH CO,NHa (JH,NH3 I ch2 i CO,OH Malamic acid. Asparagin. CO,NHa I CH,OH I CHa I CO,NHa CO,NHs I ch.nh., I CHj CO,NH3 Malamid. Unknown. Malamic acid—is not known free, but exists as its ethylic ether in malamethan. Aspartic acid—occurs in the molasses from beet-sugar, and is produced by the decomposition of asparagin by acids or alkalies. It crystallizes in sparingly soluble prisms. Malamid—is produced in large crystals, by the action of excess of NH3 on dry ethyl malate. Asparagin—is quite widely disseminated in vegetable nature, and is best obtained from asparagus, from the root of the marsh- mallow, or from vetches. It crystallizes in orthorhombic prisms with 1 Aq; sparingly soluble in water, ordorless, faintly nauseous in taste, faintly acid in reaction. Its solutions are Isevogyrous [a]j=35°-38°.8. It enters into unstable combination with both acids and bases. It is converted into aspartic acid and ammonia by heating with dilute mineral acids or alkaline solutions. It is not oxidized by HX03 unless the acid contain nitrogen oxids, in which case it decomposes asparagin into malic acid, N, and H20. 364 MANUAL OF CHEMISTRY. THIRD SERIES OF HYDROCARBONS. Series CnH 2H — 2. The hydrocarbons of this series, above the first, form two iso- meric series, designated as alpha and Beta. Those of the alpha series are produced by heating the dibromids or diiodids of the olefins with alcoholic solution of KHO. They have the general formula HCE-C—CnKm + i. Those of the Beta series are pro- duced by a variety of reactions, and have the general formula H2C=C=CnH2n. Acetylene—Ethine—C2H2—26—exists in coal-gas, and is formed in the decomposition, by heat or otherwise, of many organic sub- stances. 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 clilorid; .and collecting and decomposing the precipitate by HC1. It may be obtained by direct synthesis from H and C, by producing the electric arc be- tween carbon points in a glass globe filled with hydrogen. It is a colorless gas, rather soluble in H20; has a peculiar, dis- agreeable 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 hy- drocyanic 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, CeHB, stvrolene, CeHe, and naphthydrene, Ci0Hi0. Its presence may be detected by the formation in an ainmo- niacal solution of cuprous chlorid 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 proc- esses; thus we have gas made from wood, from coal, from fats, from petroleum, and by the decomposition of H20 and subse- quent charging of the gas with the vapor of naphtha. The typi- cal process is that in which the gas is produced by heating bitu- minous coal to bright redness in retorts. As it issues from the retorts the gas is charged with substances volatile only at high temperatures; 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 ammo.niacal compounds and other impu- rities. As it comes from the condensers, coal-gas contains: ACIDS DERIVABLE FROM ERYTHRITE. 365 * Acetylene. * Ethylene. * Marsh-gas. * Butylene. * Propylene. * Behzene. * Styrolene. * Naphthalene. * Acenaphthalene. * Fluorene. * Propyl hydrid. * Butyl hydrid. t Hydrogen. t Carbon monoxid. { Carbon dioxid. { Ammonia. ■■ Cyanogen. • Sulphocyanogen. • Hydrogen sulphid. ■ Carbon disulpliid. • Sulphuretted h y- drocarbous. f Nitrogen. { Aqueous vapor. In passing through the purifiers the gas is freed of the impuri- ties to a greater or less extent, and, as usually delivered to con- sumers, contains: * Marsh-gas. * Acetylene. * Ethylene. \ Hydrogen, j Nitrogen, f Aqueous vapor. f Carbon monoxid. f Carbon dioxid. * Vapors of hydrocarbons. TETRATOMIC ALCOHOLS. Series CrtH2tl + !1Ch. Very few of these compounds have yet been obtained. They may be regarded as the hydrates of the hydrocarbons CnH2n — 2; as the glycols are the hydrates of the ethylene series. ch2oh • CHOH Erythrite—Phycite— | =C,Hs(OH)t—123—is a product of CHOH I ch2oh decomposition of erythrin, C2(,Ho.,O10, 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 dissolving a con- siderable quantity of lime, and from this solution alcohol precipi- tates a definite compound of erythrite and calcium. By oxidation with platinum-black it yields erythroglucic acid, C|H*05. With fuming HN03 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 CnH2n05, and another of the series CnH2n —306. Although both of these acids are known, only the first, erythroglucic acid, has been obtained by oxidation of ery- thrite : * Illuminating constituents. t Impurities. i Diluent. 366 MANUAL OF CHEMISTRY ch2oh I CHOH CHOH I ch2oh COOH CHOH I CHOH CH2OH COOH CHOH I CHOH I COOH Erythrite. Erythroglucic acid. Tartaric acid. Tartaric acids—Acidum tartaricum (TJ. S., Br.)—C4H606—150.— There exist four acids having the composition which differ from each other only in their physical properties, and are very readily converted into one another; they are designated as: 1st, Bight; 2d, Left; 3d, Inactive tartaric acid; 4th, Bacemic acid. Bight or dextrotartaric acid crystallizes in large, oblique, rhombic prisms, having hemihedral facettes. Solutions of the acid and its salts are dextrogyrous. Leevotartaric acid crystallizes in the same form as dextrotartaric acid, only the hemihedral facettes are on the opposite sides, so that crystals of the two acids, when held facing each other, ap- pear like the reflections one of the other. Its solutions and those of its salts are kevogyrous to the same degree that corresponding solutions of dextrotartaric acid are dextrogyrous. Bacemic acid is a compound of the two preceding; it forms crystals having no hemihedral facettes, and its solutions are without action on po- larized light. It is readily separated into its components. In- active tartaric acid, although resembling racemic acid in its crys- talline 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 tartaric acid existing in nature, all four varie- ties may and do occur in the commercial acid, being formed dur- ing 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 H20 and the solution boiled with chalk until its reaction is neutral; calcic and potassic tartrates are formed. The insoluble calcic salt is sepa- rated and the potassic salt decomposed by treating the solution with calcic clilorid. The united deposits of calcium tartrate are suspended in II ,O, decomposed with the proper quantity of H2SO4, the solution separated from the deposit of calcium sul- phate, and evaporated to crystallization. The ordinary tartaric acid crystallizes in large prisms; very soluble in H20 and alcohol; acid in taste and reaction. It fuses A.CIDS DERIVABLE FROM ERYTHRITE. 367 at 170° (BBS" F.); at 180’ (356’ F.) it loses II20, and is gradually- converted into an anhydrid; at 200’-210° (392°-410’ F.) it is de- composed with formation of pyruvic acid, C3H ,03,and pyrotartaric acid, C„H*04 ; at higher temperatures C02, CO, 1I20, hydrocarbons and charcoal are produced. If kept in fusion some time, two molecules unite, with loss of H20, to form tartralic or ditartaric acid, C.H10On. Tartaric acid is attacked by oxidizing agents with formation of C02, H20, and, in some instances, formic and oxalic acids. Certain reducing agents convert it into malic and succinic acids. With fuming HX03 it forms a dinitro-compound, which is very unstable, and which, when decomposed below 36° (96’.8 F.), yields tartaric acid. It forms a precipitate with lime-water, soluble in an excess of H20. In not too dilute solution it forms a precip- itate with potassium sulphate solution. It does not precipitate with the salts of Ca. When heated with a solution of auric chlorid it precipitates the gold in the metallic form. As its for- mula indicates (see above), tartaric acid is tetratomic and dibasic. It has a great tendency 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 tartrates, the greater part is oxidized to carbonic acid (carbon- ates); but, if taken in sufficient quantity, a portion is excreted unchanged in the urine and perspiration. The free acid is poi- sonous in large doses. Citric acid—Acidum citricum (U. S., Br.)—C,H.07-(-Aq—19S-J-18 —is best considered in this place, although its constitution is dif- ferent from that of tartaric acid. It exists in the juices of many fruits—lemon, strawberry, etc., and in cows’ milk in the propor- tion of about 0.1$, as calcium citrate. It is obtained from lemon-juice, which is filtered, boiled, and saturated with chalk. The insoluble calcium citrate is separated and decomposed with II2S04, the solution filtered, and evaporated to crystallization. It crystallizes in large, right rhombic prisms, which lose their aq at KXF (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 aco- nitic acid, C6H606; at a higher temperature C02 is given off, and itaconic acid, C6H604, and citraconic acid, C6He04, are formed. Concentrated H2S04 decomposes it with evolution of CO; oxi- dizing agents convert it into formic acid and C02, or into acetone and C02, or into oxalic and acetic acids and C02. It is tetratomic and tribasic. In the body its salts are oxidized to carbonates. Citric acid may be distinguished from tartaric and malic acids by the following reaction; Add glycerin, fuse in a porcelain cap- 368 MANUAL OF CHEMISTRY. sule, heat until acrolein is given off, dissolve in NH4HO. Expel 1sH4HO by heat, add two drops HN03—a green color, changing to blue when heated. The known terms of this series are isomeric; have the composi- tion C6Hi406. They are closely related to the carbohydrates. Mannite—constitutes the greater part of manna, and also exists in a number of other plants. It is also produced during the so- called mucic fermentation of sugar, and during lactic fermenta- tion. It crystallizes in long prisms, odorless, sweet, fuses at 166° (330°.8 F.) and crystallizes on cooling; boils at 200° (392° F.), at which temperature it is converted into mannitan, CfHlvOf,; solu- ble in H20, very sparingly in alcohol. When oxidized it yields first mannitic, then saccharic acid (q.v.), and finally, oxalic acid. Organic acids combine with it to form compound ethers. Dulcite—Melampyrite—Dulcose—Dulcin—exists in Melampy- rum nemorosum. It forms colorless, transparent prisms, fuses at 182° (359°.6 F.), is odorless, faintly sweet, neutral in reaction, and optically inactive. It is subject to decompositions very similar to those to which mannite is subject, yielding dulcitan, CV,Hi205. Sorbite—exists in the berries of the mountain ash. Pinite— exists in the sap of the California pine, and quercite in acorns. HEXATOMIC ALCOHOLS. CARBOHYDRATES. These substances are composed of C, H, and 0; they all contain C«, or some multiple thereof; and the H and O which they con- tain are always in the proportion of H2 to O. Their constitution are still unknown; probably 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. -|-Glucose. (Dextrose.) - Lsevulose. Mannitose. -{-Galactose. Inosite. — Sorbin. — Eucalin. II. Saccharoses. n(Ci2H220n). --Saccharose. --Lactose. --Maltose. --Melitose. --Melezitose. - -Trehalose. - -Mycose. Synanthrose. -j-Parasaccharose. III. Amyloses. n^CgHioOs). --Starch. - -Glycogen. --Dextrin. — Inulin. Tunicin. Cellulose. Gums. CARBOHYDRATES. Glucose—Grape-sugar—Dextrose—Diver-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, blood, and in small quan- tity in the urine. Pathologically it is found in the saliva, per- spiration, faeces, and largely increased in the blood and urine in diabetes mellitus (see below). It may also be obtained by decom- position of certain vegetable substances called glucosids (q.v.). It is prepared artificially by heating starch or cellulose for 24 to 36 hours with a dilute mineral acid (H2S04). Glucose obtained by this method is liable to contamination with traces of arsenic, which it receives from the H2S04. Starch is also converted into glucose by the influence of diastase, formed during the germina- tion of grain. Glucose crystallizes with difficulty from its aqueous solution, in white, opaque, spheroidal masses containing 1 aq; from alcohol in fine, transparent, anhydrous prisms. At about 60° (140" F.) in dry air the hydrated variety loses H20. It is soluble in all pro- portions in hot HaO; very soluble in cold H20; soluble in alcohol. It is less sweet and less soluble than cane-sugar. Its solutions are dextrogyrous: [a]D=-j-52°.85. At 170° (338° F.) it loses H20 and is converted into glucosan, Cr.H10O5. Hot dilute mineral acids convert it into a brown sub- stance, ulmic acid, and, in the presence of air, formic acid. It dissolves in concentrated H2S04, without coloration, forming sul- phoglucic acid. Cold concentrated HN03 converts it into nitro- glucose. Hot dilute HNOs oxidizes it to a mixture of oxalic and oxysaccharic acids. With organic acids it forms ethers. Its solu- tions dissolve potash, soda, lime, baryta, and the oxids 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. Glucose in alkaline solution exerts a strong reduc- ing action, which is favored by heat; Ag, Bi, and Hg are precipi- tated from their salts; and cupric are reduced to cuprous com- pounds, with separation of cuprous oxid. In the presence of yeast, at suitable temperatures, glucose undergoes alcoholic fermenta- tion. 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 carbohydrates, which by digestion are converted into glucose. A certain quantity is also produced in the liver at the expense of glycogen, a formation which continues for some time 24 Glucoses, C6H1206—180. 370 MANUAL OF CHEMISTRY. after death. In some forms of diabetes the production of glu- cose 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 exceedingly small. It is oxidized in the body, and the ultimate products of such oxidation eliminated as C02 and H20. Whether or no intermediate products are formed, is still uncer- tain ; 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 trans- formation into C02 and H20 does not occur as a simple oxidation, as the notion that sugar or any other substance 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 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 following circumstances: Physiologically.—(1.) In the urine of pregnant women and dur- ing lactation. 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 per- sons (seventy to eighty years). (4.) In those whose food contains a large amount of starchy or saccharine 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 persons 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 CARBOHYDRATES. 371 diabetes when it appears in young persons. (2.) In diseases at- tended with interference of the respiratory processes—lung dis- eases, 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—gen- eral paresis, dementia, epilepsy; by puncture of the fourth ven- tricle. (5.) In intermittent and typhus fevers. (6.) By the action of many poisons—carbon monoxid, arsenic, chloroform, curari; by injection into an artery of ether, ammonia, phosphoric acid, sodium chlorid, 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 condi- tions previously mentioned. The quantity of urine is increased, sometimes enormously, and it is of high sp. gr. The elimination of urea is increased 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 very large; 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 maxi- mum 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 that the determination be made in a sample taken from the mixed urine of twenty-four hours. Analytical Characters.—A saccharine urine is usually abun- dant in quantity, pale in color, of high sp. gr., covered with a persistent 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 dilute 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. 25) it deviates the plane of polarization to the right. (2.) When mixed with an equal volume of liquor potass* and MANUAL OF CHEMISTRY. heated, it turns yellow, and, if sugar be abundant, brown. A molasses-like odor is observable on adding HN03 (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 pres- ent; 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 solu- tion and about 1 c.c. of caustic potassa solution; if sugar be pres- ent the bluish precipitate is dissolved on agitation, forming a blue solution. The clear blue fluid, when heated to near boiling, de- posits a yellow, orange, or red precipitate of cuprous oxid if sugar be present (Trommer’s test). In the application of this test an excess of cupric sulphate is to be avoided, lest the color be masked by the formation of the black cupric oxid. Sometimes no precip- itate is formed, but the liquid changes in color from blue to yel- low. This occurs in the presence of small quantities of cupric salt and large quantities of sugar, the cuprous oxid 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, creatinin, coloring matter, etc., and instead of a bright precipitate, a muddy deposit is formed. When this occurs the urine is heated with animal charcoal and filtered; the filtrate evaporated to dryness; the residue extracted with alcohol; the alcoholic extract evaporat- ed; the residue redissolved in water, and tested as described above. (5.) Four or five c.c. of Feliling’s solution (see p. 374) are heated in a test-tube to boiling; it should remain unaltered. The urine is then added, and the mixture boiled after each addition of 4-5 drops; if it contain sugar, the mixture turns green, and a yellow or red precipitate of cuprous oxid is formed, usually darker in color than that obtained by Trommer’s test. The absence of glu- cose is not to be inferred 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, car- bonate 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 pow- der turns brown or black by reduction to elementary bismuth CARBOHYDRATES. 373 (Boettger’s test). No other normal constituent of the urine reacts with this test; a fallacy is, however, possible from the presence of some compound, which, by giving up sulphur, may cause the for- mation of the black bismuth sulphid. To guard against this, when an affirmative result has been obtained, another sample of urine is rendered alkaline and boiled with pulverized litharge; the i>owder should not turn black. Nylander’s test is a mere modification of Boettger’s, in which the Bi is used in solution. The test solution is made by dissolv- ing 2.5 parts Bi (N03)3 and 4 parts of Rochelle salt in 100 parts of a solution of NaHO of 8# strength. To use the reagent it is mixed with one-tenth its volume of the urine and boiled. In the pres- ence of glucose a black ppt. is formed. The same precautions with regard to sulphur compounds are necessary. (7.) A solution of sugar, mixed with good yeast and kept at 25° (77° F.) is decomposed into COa and alcohol. To apply the fer- mentation-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 collected 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 polarime- ter.—The filtered urine is observed by the polari scope (see p. 25) and the mean of half a dozen readings taken as the angle of devi- ation. From this the percentage of sugar is determined by the formula jp=- a—in which p=the weight, ingrains, of glucose 52.85 X l in 1 c.c. of urine; a=the angle of deviation; Z=the length of the tube in decimetres. The same formula may be used for other substances by substituting for 52.85 the value of [a]D for that sub- stance. If the urine contain albumen, it must be removed before determining the value of a. • (2.) By specific gravity; Robert’s method.—The sp. gr. of the 374 MANUAL OF CHEMISTRY. urine is carefully determined at 25° (77° F.); yeast is then added, and the mixture kept at 25° (77° F.) until fermentation is com- plete ; the sp. gr. fs again observed, and will be found to be lower than before. Each degree of diminution 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 solutions, the one to which we give the preference is that of Or. Piffard. Two solutions are required: I. Cupric sulphate (pure, crystals) 51.98 grams. 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 volumes of No. II. The copper contained in 20 c.c. of this mix- ture is precipitated as cuprous oxid 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 sugar, and with nine times its volume if highly saccharine (the degree of dilution required is, with a little prac- tice, 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 am- monia) are added to the Fehling’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, Avlien 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 vol- umes of water, or by ten if with nine volumes, gives the number 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 obtained 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 5 gram glucose. Patient is passing 2,436 c.c. urine in twenty-four hours. decigr. =33.36 grams glucose in twenty-four 7.0 hours. The accuracy of the determination may be controlled bv fllter- CARBOHYDRATES. ing 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 ferrocyanid 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 oxid be observed, an excess of urine has been added, and the result obtained is less than the true one. This method, when carefully conducted with accurately pre- pared and undeteriorated solutions, is the best adapted to clini- cal 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 obtainable by Fehling’s volumetric process are desired, recourse must be had to a determination of the weight of cuprous oxid obtained by reduction. A small quantity of freshly prepared Fehling’s solution is heated to boiling in a small flask; to it is gradually added, with the precautions observed 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 Ha0, corked, and allowed to cool. The alkaline fluid is separated as rapidly as possible from the precipitated oxid, by decantation and filtration through a small double filter, and the precipitate and flask re- peatedly washed with hot Ha0 until the washings are no longer alkaline ; a small portion of the precipitate remains 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 HN03; 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 oxid, of which 220 parts=100 parts of glucose. Leevulose—Uncrystallizable sugar—forms the unerystallizable portion of the sugar of fruits and of honey, in which it is associ- ated with glucose; it is also produced artificially by longed 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, 376 MANUAL OF CHEMISTRY [a]u= —106° at 15° (59° F.). At 170° (338° F.) it is converted into the solid, amorphous laevulosan, C6HJU05. Mannitose—- is obtained by the oxidation of mannite. It is a yellow, uncrystallizable sugar, having many of the characters of glucose, but optically 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]D=-)-830.33, and in being oxi- dized to mucic acid by HNOs. The substance called cerebrose, obtained by the action of H3SO4 on cerebrin and other constitu- ents of nerve-tissue, is identical with galactose. Inosite—Muscle-sugar—exists in the liquid of muscular tissue, in the lungs, kidneys, liver, spleen, brain, and blood; patholog- ically in the urine in Bright’s, diabetes, and after the use of dras- tics 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 con- jecture. 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 sol- uble 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 chemical composition, as it does not possess the other character- istics of the group. It does not enter directly into alcoholic fer- mentation, although upon contact with putrefying animal mat- ters it produces lactic and butyric acids; when boiled with barium or‘potassium hydrate, it is not even colored; in the presence of inosite, potash precipitates with cupric sulphate solution, the precipitate being redissolved in an excess of potash; but no re- duction takes place upon boiling the blue solution. The presence of inosite is indicated by the following reactions: Scherer's.—Treated with HN03, the solution evaporated to near dryness, and the residue moistened with ammonium hydrate and calcium clilorid, and again evaporated; a rose-pink color is pro- duced. Succeeds only with nearly pure inosite. Gallots'.—Mer- curic nitrate produces, in solutions of inosite, a yellow precipitate, which, on cautious heating, turns red; the color disappears on cooling, and reappears on heating. Saccharoses, Ci2H220n—342. Saccharose—Cane-sugar—Beet-sugar—Saccharum (U. S.)—the most important member of the group, exists in many roots, fruits, CARBOHYDRATES. 377 and grasses, and is produced from the sugar-cane, Saecharum officinarum, sorghum, Sorghum saccharatum, beet, Beta vul- garis, and sugar-maple, Acer saccharinum. 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 precipitation of albumen, wax, calcic phosphate, etc.; the clear liquid is drawn off, and “ deliined ” by passing a current of C02 through it; the clear liquid is again drawn off and evap- orated, during agitation, to the crystallizing-point; the product is drained, leaving what is termed raw or muscovado 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 temperature not exceeding 72° (101°.6 F.), to the crystallizing-point. The product 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 ammonium 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 rock-candy, is cane-sugar allowed to crystallize slowly from a concentrated solution without agitation. Maple-sugar is a par- tially refined, but not decolorized variety 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 addition of alcohol. Aqueous solutions of cane-sugar are dextrogyrous, [«]„=-}-73°.8. When saccharose is heated to 160° (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 glucose and lsevulosan; at a still higher temperature, HaO is given off, and the glucose already formed is converted into glucosan; at 210° (410° F.) the evolution of HaO is more abundant, and there remains a brown material known as caramel, or burnt sugar; a tasteless substance, insoluble in strong 378 MANUAL OF CHEMISTRY. alcohol, but soluble in HjO or aqueous alcohol, and used to com- municate color to spirits; finally, at higher temperatures, methyl hydrid and the two oxids of carbon are given off; a brown oil, acetone, acetic acid, and aldehyde distil over; and a carbona- ceous residue remains. If saccharose be boiled for some time with H20, it is converted into inverted sugar, which is a mixture of glucose and laevulose: With a solution of saccha- rose the polarization is dextrogyrous, but, after inversion, it be- comes hevogyrous, because the left-handed action of the molecule of laevulose produced, [a]D= —106°, is only partly neutralized by the right-handed action of the glucose, [a]D=+ 52°.85. This in- version 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 being to remove the H20 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 saccharids, 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 inverted sugar; (3) concentrated acids decompose cane-sugar entirely, more rapidly when heated than in the cold; with HC1, formic acid and a brown, flocculent material (ulmicacid?) are formed; with H2S04, S02 and HaO are formed, and a voluminous mass of charcoal re- mains. Oxalic acid, aided by heat, produces C02, formic acid, and a brown substance (humin?). 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 H2S04. Dilute IIN03, when heated with saccharose, oxidizes it to saccharic and oxalic acids. Concentrated HN03, alone or mixed with H2S04, converts it into the explosive nitro-saccharose. Potassium permanganate, 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 proportional 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 de- composed by the alkalies much less readily than glucose, with formation of acids of the fatty series and oxalic acid. CARBOHYDRATES. 379 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, containing an excess of sugar. A solution containing 100 parts of sugar in 000 parts of HaO dis- solves 33 parts of calcic oxid. These solutions have an alkaline taste; are decomposed, with formation of a gelatinous precipi- tate, when heated, and with deposition of calcium carbonate and regeneration of saccharose, when treated with C02. Quantities of calcium suerates are frequently introduced into sugars to in- crease 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 solution 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 obtained from skim-milk by coagulating the casein with a small quantity of H5SO4, filtering, evaporating, redissolving, decolorizing with animal charcoal, 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 HaO; soluble in acetic acid; insoluble in alcohol and in ether; its solutions are dextrogyrous [a]D=-f59°.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. HNO3 oxidizes it to mucic and oxalic acids. A mixture of HN03 and H3SO4 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 saccharose, 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 fermen- tation, which takes place slowly, and, as it appears, without pre- vious transformation of the lactose into either glucose or galac- tose. On contact with putrefying albuminoids it enters into lactic fermentation. The average proportion of lactose in different milks is as fol- lows: Cow, 5.5 per cent.; mare, 5.5; ass, 5.8; human, 5.3; sheep, MANUAL OF CHEMISTRY. 4.2; goat, 4.0. When taken internally, it is converted into galac- tose by the pancreatic secretion; when 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 properties, is formed along with dextrin during the conversion of starch into sugar by the action of diastase and of the eryptolytes Fig. 40 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, n(C6H10O5)—wl62. Starch—Amylum (TJ. S.)—the most important member of the group, exists in the roots, stems, and seeds of all plants. It is CARBOHYDRATES. 381 prepared from rice, wheat, potatoes, maniot, beans, sago, arrow- root, etc. The comminuted vegetable tissue is steeped for a con- siderable time in HaO rendered 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 decantation, 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 obtained. 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 concentric lines more or less well marked. Differences in size, shape, and markings of starch gran- ules are shown in Fig. 40. Starch is not altered by exposure to air, except that it absorbs moisture. Commercial starch contains 18 per cent, of HaO, 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 HaO be gradually heated with 1 part of starch, the granules swell at about 55° (131° F.), and at 80° (176° F.) they have reached 3® times their original dimensions; their structure is no longer distinguishable, and they form a trans- lucent, gelatinous mass, commonly known as starch-paste. In this state the starch is said to be hydrated, and, if boiled with much HaO, and the liquid fdtered, a solution of starch passes through, which is opalescent from the suspension in it of undis- solved 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° (440° F.) it forms a brownish-yellow, fused mass, composed principally of pyrodextrin. Hydrated starch is converted into dextrin by heating with HaO 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 ob- served in the table on page 382. If starch be ground up with dilute H2SO4, 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 HaO, especially at 50° (122° F.), and in having a lower rotary power, [a]D=+211°. If the action be prolonged, the value of [a]D continues to sink until it reaches +73°.7, when the product consists of a mixture of dextrin and 382 MANUAL OF CHEMISTRY. glucose. Concentrated HN03 dissolves starch in the cold, form- ing a nitro-product called xylodin or pyroxam, which is insoluble in HaO, soluble 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, com- pounds are formed which seem to be ethers, and to indicate that starch is the hydrate of a trivalent, oxygenated radical, (CeH702)'". Potash and soda in dilute solution convert starch into the soluble modification mentioned above. Nitrogenized matter. Starch. Dextrin, etc. Cellulose. Fat. Mineral mat- ter. Carbohy- drate. Water. V egetable fibre, etc. Authority. Wheat, hard 22.75 58.62 9.50 3.50 2.61 3.02 Payen. Wheat, hard 19.50 65.07 7.60 3.0 2.12 2.71 Payen. Wheat, hard 20.0 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 12.65 76.51 6.05 2.80 1.87 2.12 Payen. Rye 12.50 64.65 14.90 3.10 2.25 2.60 Payen. Barley 12.96 66.43 10.0 4.75 2.76 3.10 Payen. Oats 14.39 60.59 9.25 7.06 5.50 3.25 Payen. Maize 12.50 67.55 4.0 5.90 8.80 1.25 Payen. Rice 7.55 14.45 10.80 88.65 1.0 1.10 0.80 1.25 0.90 1.60 68.48 14.22 Payen. Payen. Letheby. Flour 2.0 1.70 70.50 15.0 Bread 8.10 1.60 2.30 51.00 37.0 Letheby. Oatmeal 12.60 5.60 3.0 63.80 15.0 Letheby. Buckwheat 13.10 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 65.85 1.05 2.0 3.65 8.40 Payen. White bean 25.50 55.70 2.09 2.80 3.20 9.90 Payen. Peas, dried 23.80 58.70 3.50 2.10 2.10 8.30 Payen. Lentils 25.20 56.0 2.40 2.60 2.30 11.50 Payen. Potato 2.50 20.0 1.09 1.04 0.11 1.26 74.0 Paven. 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 9.60 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. 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 cool- ing. If to a solution of starch, blued by I, a solution of a neutral salt be added, there separates a blue, flocculent deposit of the so-called iodid of starch. Iodin renders starch soluble in water, and a soluble iodized starch, Amylum iodatum (U. S.), is obtained by triturating together 19 pts. starch, 2 pts. water, and 1 pt. iodin, and drying below 40° (104° F.). Starch has not been found in the animal economy outside of the CARBOHYDRATES. 383 alimentary canal, in which, as a prerequisite to its absorption, it must be converted into dextrin and glucose. This change is par- tially effected by the action of the saliva; more rapidly with hy- drated 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 cryptolyte, a further transformation into glucose, and of a portion into lactic and butyric acids, takes place. During the germination of grain, as in the process of malting, a peculiar, nitrogenized substance is produced, which is known as diastase. Under the influence of this body the starch is more or less completely converted into glucose, in very much the same way as the conversion occurs in the body. This “ diastatic” action, whether produced by vegetable or ani- mal processes, does not take place by a simple conversion of starch into glucose, by some such single reaction as that expressed by CbHioOs-l-UnC —— CeH 1 aOfi, but by successive stages in which “ solu- ble starch ” is first produced, then several bodies called dextrins, then maltose, and finally glucose. (See Dextrin, p. 384.) Glycogen occurs in the liver, the placenta, white blood-corpus- cles, pus-cells, young cartilage-cells, in many embryonic tissues, and in muscular 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 Ha0, insoluble in alcohol and ether. In H20 it swells up at first, and forms an opalescent solu- tion, which becomes clear on the addition of potash. Its solu- tions 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 HN03 converts it into xyloidin ; on boiling, into oxalic acid. Its solutions dissolve cupric hy- drate, which is, however, not reduced on boiling. Iodin colors glycogen wine-red. Concerning the method of formation of glycogen in the econ- omy, 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 modification of the carbohydrates, it may be and is produced from the albuminoids 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. This transformation is con- 384 MANUAL OF CHEMISTRY. tinuous in the liver during life, and is accomplished through the same series of intermediary changes into dextrins and maltose as in the case of the conversion of starch into sugar, except that possibly the structure of the dextrins may be different. Dextrin—British gum—a substance resembling gum arabic in appearance 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 H2S04 to 90° (194° F.) until a drop of the liquid gives only a wine-red color with iodin; neutralizing with chalk, filtering, concentrating, precipitating with alcohol; (8) 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. Commercial dextrin is a colorless, or yellowish, amorphous powder, soluble in H20 in all proportions, forming mucilaginous liquids. When obtained by evaporation of its solution, it. forms masses resembling gum arabic in appearance. Its solutions are dextrogyrous, and reduce cupro-potassic solutions under the in- fluence of heat, to amounts varying with the method of formation of the sample. It is colored wine-red by iodin. It is extensively used as a substitute for gum acacia. By the action of diastase upon starch, four dextrins are pro- duced : 1st, Erythrodextrin, which is colored red by iodin, and which is easily attacked by diastase; 2d, Achroodextrin a, not colored by iodin; partially converted into sugar by diastase; rotary power [a]D=-j-210°; reducing power (glucose=100)=12; 3d, Achroodextrin /3, not colored by iodin, nor decomposable in 24 hours by diastase; rotary power-f 190°; reducing power=12; 4th, Achroodextrin y, not colored by iodin, nor decomposed by dias- tase ; slowly converted into glucose by dilute H,S04; rotary power =—|—150°; reducing power=28. An explanation of this series of transformations has been sug- gested in the supposition that the molecule of starch consists of 50(012II2 0 010); that this is first converted into soluble starch 10(Ci2H2oOio), and that this is then converted into the different forms of dextrin by a series of hydrations attended by simultane- ous formation of maltose, of which the final result might be representd by the equation: 10(012H2oOio) -)- 8(H20) — 2(Ci2H2oOio) -f- 8(012H22 O11) Soluble starch. Water. Achroodextrin. Maltose. Cellulose—Cellulin—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 boil- CARBOHYDRATES. in# with potash, and afterward with dilute HC1, yields pure cel- lulose, in which form it is now met with in commerce under the name “absorbent cotton.” It is a white material, having the shape of the vegetable struc- ture from which it was obtained; insoluble in the usual neutral solvents, but soluble in the deep-blue liquid obtained by dissolv- ing copper in ammonia in contact with air. Vegetable parchment, or parchment paper, is a tough material, possessing many of the valuable properties of parchment, made by immersing unsized paper for an instant in moderately strong H2S04, washing thoroughly, and drying. Nitro-cellulose.—By the action of HN()3 upon cellulose (cotton) three different products of substitution maybe obtained: mono- nitro-cellulose, soluble in acetic acid, insoluble in a mixture of ether and alcohol; dinitro-cellulose, insoluble in acetic acid, solu- ble in a mixture of ether and alcohol; trinitro-cellulose, soluble in both the above solvents. Gun-cotton or pyroxylin is composed of varying proportions of these three derivatives. When gun- cotton is required as an explosive agent, the process is so man- aged that the product shall contain the greatest possible propor- tion 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 valu- able. To obtain this, a mixture is made of equal weights of HN03 and H2SO4 (of each about 5 times the weight of the cotton 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 precipitated by barium chlorid, and dried. Col- lodion is a solution of dinitro-cellulose in a mixture of three vol- umes of ether and one volume of alcohol. Celluloid is gun-cotton and camphor compacted under pressure. Lignin is an isomere of cellulose, which constitutes the greater part of the “ incrusting substance ” of wood. Gums—are substances of unknown constitution, existing in plants; amorphous; soluble in water, insoluble in alcohol; con- verted into glucose by boiling with dilute H2S04. Lichenin is obtained from various lichens by extraction with boiling water, forming a jelly on cooling; it is oxidized to oxalic acid byIO03; is colored yellow by iodin; and is precipitated from its solutions by alcohol. Arabin is the soluble portion of gum arabic and gum Senegal— Acacia (U. S.). To separate it, gum arabic is dissolved in water acidulated with HC1, and precipitated by alcohol. It is a white, amorphous, tasteless substance, which is not colored by iodin; is xidized by HN03 to mucic and saccharic acids; is converted by 386 MANUAL OF CHEMISTKY. H2SO4 into a non-ferraentable sugar, arabinose; and has the com- position, Ci2H2oOio+lAq. 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. CYCLIC HYDROCARBONS. 387 CYCLIC HYDROCARBONS AND THEIR DERIVATIVES. Aromatic Substances. It is among the compounds of this series that the most impor- tant products of synthetic chemistry are to be found ; and it is in dealing with them that theoretic chemistry has received the widest applications. Although many of these bodies occur in nature, by far the greater number, including all the hydrocarbons except the mem- bers of the paraffene and terebenthene groups, are artificial products. Although the members of the acyclic and of the cyclic families are not readily converted into each other, acyclic com- pounds are frequently grafted upon cyclic, and cyclic compounds are fre- quently decomposed with formation of acyclic de- rivatives, but in the lat- ter case cyclic derivatives are simultaneously pro- duced. Among the instances of conversion of acyclic into cyclic compounds is one of interest as bearing upon the constitution and relationships of the cyclic hydrocarbons, and as showing their pyrogenic origin. We have seen that one of the constituents of coal-gas is acety- lene, H—CeeC—H. The central figure of the cyclic compounds is benzene, C6H6, which is obtained principally from gas-tar; and whose molecule may clearly be considered as produced by the union of three molecules of acetylene, 3C2H2= C6H6. If we represent three molecules of acetylene by 1, 2, 3, A or B, Fig. 41 (the larger circles representing the carbon, and the smaller the hydrogen atoms), it is easy to conceive that by the action of heat one of the three bonds uniting the two C atoms may be loosened, and that the neighboring C atoms will then attach themselves to each other, exchanging the valences thus liberated, and produce a molecule of benzene. The arrangement A produces the “ pris- Fig. 41 388 MANUAL OF CHEMISTRY. matic formula,” the arrangement B the “hexagonal formula” of benzene, usually represented in writing thus : HC CH \H/ HC—j—CH H H C HC/XCH HCX/CH C H or It is hardly necessary to mention that such formulae are merely schematic, intending to represent the relations of the atoms, but not intending to convey any idea of the shape of the molecule. Although the hexagonal expression is more frequently met with than the prismatic, and is in some respects more manageable, the prismatic in some cases better explains the structure of the mole- cule. Although substances are known which contain a cyclic nucleus made up of a number of C atoms less than six, all cyclic com- pounds may be considered as derivable from benzene, and all con- tain the benzene nucleus or benzene ring, C(iH„, more or less mod- ified by addition, by substitution or by subtraction. Some of the benzene derivatives are produced by simple graft- ing of lateral, open-chain groups upon a benzene nucleus, as shown at A, others by the union of two or more benzene rings with each other as shown at B ; H /C\ H H HC C—C—C—H Hi h?.* N0/ H A. H H HC C CH Hi i JjH \/\/ H H B. and all the molecules so formed are capable of deeper modifica- tion by further substitution of atoms or groups for the remaining H atoms. The prismatic formula given above may also be opened out, and the molecule thus gain two, four, or six valences, thus : \/ c /\ —c—c— 44- \/ c \/ c /\ -c-c— >w< x \/ x c /\ \/ c )C c( <1 i> )c c< c /\ MONOBENZENIC HYDROCARBONS. 389 Condensation and substitution may also occur in the benzene ring itself, giving rise to compounds containing modified nuclei, such as: A -c\—C— 4 & L x/\/ c c I /\ A /\ —C C—. 4 'c- X/ N N'C=C// The benzenic hydrocarbons (and their derivatives) are divided into groups according to the number of benzene nuclei, more or less modified, which they contain. Thus we have : Monobenzenic hydrocarbons—containing one benzene nucleus. Dibenzenic hydrocarbons—containing two benzene nuclei. Tribenzenic hydrocarbons—containing three benzene nuclei, etc. MONOBENZENIC HYDROCARBONS, Series CnH in— a The hydrocarbons of this series are the starting-points from which the major part of the cyclic compounds are obtainable or derivable. Those at present known are : Benzene C6H0 boils at 80\4 (176°.7 F.) Toluene CtH? boils at 1103.3 (230°.5 F.) Xylene C8H10 boils at 142°.0 (287°.6 F.) Cumene C9H12 boils at 151°.4 (304°.5 F.) Cymene C10H14 boils at 175°.0 (347°.0 F.) Laurene CuHk boils at 188°.0 (370°.4 F.) The terms above benzene may be obtained by a general reac- tion, by treating a mixture of monobrombenzene, ether and the bromid or iodid of the corresponding alcoholic radical with sodium in excess: Monobrom- benzene. C6H6Br + CHsBr + Na2 = 2 NaBr + C6H5,CH3 Methyl bromid. Sodium. Sodium bromid. Methylbenzene. Toluene. The reaction is violent and small quantities only (80-40 grams) can be operated on. Benzene—Benzol—Phenyl hydricl—CtiH6—78—(not to be con- founded with the commercial benzine, a mixture of hydrocarbons of the series CnHjn+s, obtained from petroleum) does not exist in nature, but is produced in a number of reactions. It is obtained by one of two methods, according as it is required chemically pure or mixed with other substances. 390 MANUAL OF CHEMISTRY. To obtain it pure, recourse must be had to the decomposition of one of its derivatives, benzoic acid ; this substance is inti- mately mixed with 3 pts. slacked lime, and the mixture heated to dull redness in an earthenware retort, connected with a well- cooled receiver ; the upper layer of distilled liquid is separated, shaken with potassium hydrate solution, again separated, dried by contact with fused calcium chlorid, and redistilled over the water-bath. For use in the arts, and for most chemical purposes, benzene is obtained from coal- or gas-tar, an exceedingly complex mixture, containing some forty or fifty substances, among which are : Benzene. Toluene. Xylene. Cumene. Hydrocarbons. Cymene. Naphthalene. Acenaphthalene. Fluorene. Anthracene. Retene. Chrysene. Pyrene. Acids. Carbolic. Cresylic. Phi or y lie. Rosolic. Oxyphenic. Pyridin. Anilin. Picolin. Lutidin. Collidin. Leucolin. Iridolin. Cryptidin. Bases. Acridin. Coridin. Rubidin. Viridin. By a primary distillation of coal-tar the most volatile constitu- ents, including benzene, are separated as light oil; this is washed, first with H2SO4, and then with caustic soda, and afterward re- distilled ; that portion being collected which passes between 80° and 85° (176°-185° F.). This is the commercial benzene, a product still contaminated with the higher homologues of the same series, from which it is almost impossible to separate it, but whose pres- ence is necessary for the principal use to which benzene is put— the manufacture of anilin 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 substitution ; the corresponding iodin compounds can only be obtained by indirect methods. Sulphuric acid combines with benzene to form a neutral substance, sulpho-benzid, when the anhydrous acid is used, and phenyl-sulphurous acid with the or- dinary H2SO4. If fuming HN03 of sp. gr. 1.52 be slowly added to benzene, a MONOBENZENIC HYDROCARBONS. reddish liquid is formed ; from which, on the addition of H20 a reddish-yellow oil separates, and is purified by washing with HaO and with sodium carbonate solution, drying and rectifying. This oily material is mononitro-benzene (see p. 411). If benzene be boiled with fuming HNOs, or if it be dropped into a mixture of HN03 and H2S04, so long as the fluids mix, a crystalline product, dinitro-benzene, is formed. The superior homologues of benzene include many isomeres. As they are derivable from benzene by substitution of a hydro- carbon radical or radicals Cnllm + i for one or more atoms of hydrogen, the following isomeres may exist: CeH4(CH3)2 = Diinethylbenzene C6H5(C2H5) = Ethylbenzene C8H10 C6H3(CH3)3 = Trimethylbenzene C8H5(C3H7) = Propylbenzene C8H,(CH3)(C2HS) = Methyletliylbenzene = CaHia C8H2(CH3)4 = Tetramethylbenzene C8H4(C2H5)2 = Diethylbenzene C6Hs(C4H9) = Butylbenzene C8H3(CH3)2(C2H5) = Dimethylethylbenzene C8H4(CH3)(C3H7) = Methylpropylbenzene CloHl4 The number of isomeres among the higher terms of the series is further increased by the occurrence of increasing numbers of isomeres among the substituted radicals themselves, as CH2—CHo—CH3 and CH etc. Further, when the number of substituted groups is greater than one, different substances are produced by the substitution of the same groups in positions bearing different relations to each other in the benzene nucleus. In the case of benzene itself there exist products of substitu- tion containing 1, 2, 3, 4, 5, and 6 groups CH3,C2H5, etc. (or other radicals or univalent atoms), or combinations of two or three of those radicals or elements. In the case of the unisubstituted de- rivatives, C6H5,CH3; C6H5,C2H5, etc., but one of each exists. Of the bisubstituted, trisubstituted, and quadrisubstituted deriva- tives three of each are known. From the existence of but one unisubstituted derivative it is obvious that it is immaterial in which of the CH groups this sub- stitution occurs, and hence these six groups are equal to each other in value. The existence of isomeres of the higher products of substitution depends upon differences in the relative positions of the substituted radicals or atoms to each other, their orienta- tion, as it is called, and not to their absolute positions. If we represent the molecule of benzene by a hexagon, leaving out the H atoms for the sake of brevity, we may start from any angle and number the angles, or positions, from 1 to 6 : 392 MANUAL OF CHEMISTRY. A 6—C C—2 s4 A-s \c/ 4 In such a hexagon there are three possible positions with rela- tion to each other, in which two atoms or radicals may be placed. They may be consecutive, i.e.. occupying two adjoining posi- tions, as 1—2, 2—3, 3—4, 4—5, 5—6, or 6—1 ; as for instance ini, in which x may be a radical CnHan + l, a univalent atom, or any x C /IX C6 2Cx 3C X4/ 1. x C /IX C6 2C C5 3(lx \4 / C 2. x C /IX C6 2C U5 3(1 \ 4/ C x 3. univalent radical. Or the positions may be unsymmetrical, 1—3, 2—4, 3—5, 4—6, 5—1, as in 2. Or the substitution may be symmet- rical, as in 3, occupying the diagonal positions 1—4, 2—5, 3—6. In the case of trisubstituted derivatives in which the substi- tuted radical or element is the same there may also be three posi- tions, thus : x C / IX C6 2Cx (35 3 Phenol-phthalein is a yellow, crystalline powder, insoluble in water, but soluble in alcohol. Its alcoholic solution, perfectly colorless if neutral, assumes a brilliant magenta-red in the presence of an alkali. This property renders phenol-phthalein very valuable as an indicator of re- action. Resorcin-phthalein—Fluorescein—C2oH1206—bears the same re- lation to resorcin that phenol-phthalein does to phenol, and is obtained from resorcin by a corresponding method. It is a dark brown crystalline powder, which dissolves in ammonia to form a red solution, exhibiting a most brilliant green fluorescence. A tetrabromo-derivative of fluorescein is used as a dye under the name eosin. AROMATIC ALCOHOLS. The alcohols corresponding to this series of hydrocarbons have the composition as the corresponding phenols, from which they differ in constitution, and in having the functions of true alcohols. They yield on oxidation, first an aldehyde and then an acid, and they contain the characterizing group of the primary alcohols, CEUOH ; once if the alcohol be monoatomic, twice if diatomic, etc. Thus : CsH6,CH2OH = Benzylic alcohol. CeHi.COH = Benzoic aldehyde. C6H5,COOH = Benzoic acid. ALPIIENOLS, ALDEHYDES. 405 As they contain the benzene nucleus, they are capable of yield- ing isomeric products of further substitution, ortho, para, or meta, according to the position of the substituted atoxn or radical. Benzylic alcohol—Benzoic alcohol—Benzyl hydrate-CcH5(CH,OH) —108—does not exist in nature, and is of interest chiefly as cor- responding to two important compounds, benzoic acid and ben- zoic 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 aro- matic odor ; is insoluble in water, soluble in all proportions in alcohol, ether, and carbon disulphid. By oxidation it yields, first, benzoic aldehyde, CeH5(COH) ; and afterward, benzoic acid, CbH5(COOH). By the same means it may be made to yield products similar to those obtained from the alcohols of the satu- rated hydrocarbons. ALPHENOLS. These substances are intermediate in function between the alcohols and the phenols, and contain both substituted groups (OH) and CHaOH. / CH OH Saligenin, CRH,; qjj2 —124—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 further oxidation yields salicylic acid. It is also formed by the action of nascent hydrogen on salicylic aldehyde. ALDEHYDES. Benzoic aldehyde—Benzoyl hydrid—C«H5(COH)—106—is the main constituent of oil of bitter almonds, although it does not exist in the almonds (see p. 436); it is formed, along with hydro- cyanic acid and glucose, by the action of water upon amygdalin. It is also formed by a number of general methods of producing aldehydes ; by the dehydration of benzylic alcohol; by the dry distillation of a mixture in molecular proportions of calcium benzoate and formate ; by the action of nascent hydrogen upon benzoyl cyanid, 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 concentrated solution of sodium bisulphite ; the crystalline mass is expressed, dissolved in a small quantity of 406 MANUAL OF CHEMISTRY. water, and decomposed with a concentrated 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 chlorid or bromid. H2S04 dissolves it when heated, forming a purple- red color, which turns black if more strongly heated. When perfectly pure, benzoic aldehyde exerts no deleterious action when 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 292. Salicylic aldehyde—Salicyl hydrid—Salicylal—Salicylous acid —C6H4(OH)COH—122—exists in the flowers of Spircea ulmaria, and is the principal ingredient of the essential oil of that plant. It is best obtained by oxidizing salicin (q.v.). It is a colorless oil; turns red on exposure to air ; has an agree- able, 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 function, possessing the characteristic properties of aldehyde and phenol. It produces a great number of derivatives, some of which have the characters of salts and ethers. Methyl-protocatechuic aldehyde — Vanillin— Cr,H8(OH)(OCH3) COH —is the odoriferous principle of vanilla. It is produced artificially by oxidation of coniferin, a glucosid occur- ring in coniferous plants. It crystallizes in needles, fuses at 80° (176° F.) ; is sparingly soluble in water, readily soluble in alcohol or ether. It has a pungent taste, and a faint odor of vanilla, the latter more marked, when the substance is heated. On ex- posure to air it becomes partially oxidized to vanillic acid CaHa04. KETONES. The ketones of this series are produced by the union of a ben- zene nucleus with an alcoholic radical through a group (CO)" thus : C6H5,CO,CH3. They are also called phenones. Phenyl methyl ketone—Aceto-phenone—Hypnone—C(;Hr,.CO, CH 3—is obtained by distilling a mixture of calcium benzoate and ACIDS CORRESPONDING TO AROMATIC HYDRATES. acetate; or by the action of zinc-methyl upon benzoyl clilorid. It forms large crystalline plates, fusible at 14° (57°.2 F.). It has been used as a hypnotic ACIDS CORRESPONDING TO THE AROMATIC HYDRATES. The acids possibly derivable from benzene by the substitution of (COOH), or of (CQOH) and (OH), for atoms of hydrogen, would form, were they all known, a great number of series ; there are, however, comparatively few of them which have been as yet obtained, although the number 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: P rr /CH OH Usrt4\CH,OH p rr /CH2OH 1 ,il4\OH C6Hs—CHaOH Benzoic alcohol, Toluyl glycol. Saligenin. CeH5—COOH r xr /COOH ' 6±l4\COOH P H /COOH ' ‘H4\OH Benzoic acid. Terephthalic acid Salicylic acid. By the progressive substitution of groups (COOH) for atoms of hydrogen in benzene, we may obtain six series of acids, live of which have been isolated : C6H5(COOH) —CnHm— 802 Benzoic series. C6H4(COOH)2—CnHjn—io04 Phthalic series. C6H3(COOH)3—CnHj»-isO# Trimellitic series. C6H2(COOH)4—CnH2n-i408 Prehnitic series. C8H(COOH)5 — CnHsn-isOio Wanting. C6(COOH)6 —CnHm-uOu Mellitic series. There may also be three distinct series of bi- tri- and tetra- acids produced by differences in orientation (see p. 391), according as the groups COOH occupy consecutive, symmetrical or unsym- metrical positions. The alphenols, containing a single group (OH), are at present represented by a single series : C6H4(OH)(COOH)—CnH2n—s03—Salicylic series. Corresponding to unknown alphenols, containing a greater number of (OH) groups, there are at present two series of acids known : C6H3(OH)2(COOH)—CnH2n—804—Veratric series, and C6H2(OH)3(COOH)—CnHan—eOs—Gallic series. 408 MANUAL OF CHEMISTRY. In each of these series the basicity is, as usual, equal to the number of groups (COOH). Benzoic acid—Acidum benzoicum (TJ. S.)—C6H5(COOH)—122— exists ready formed in benzoin, tolu balsam, castoreuin, 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 (—N CoHb-N/U + + C6Hs—N/ Azoxybenzene. Azobenzene. C«H5-N\ , „ C,H6NH\ C6Hb—N/ + n,i - C«H5NH/ Azobenzene. cIhInh) + H' = 2[C.H.(NH,)] Hydrazobenzene. Hydrazobenzene. Amlin PYKIDIN BASES. 415 The diazo compounds consist of an univalent remainder of an aromatic hydrocarbon, united by the group (—N = N—) with a haloid atom, or an acid residue: CeHs—N = N—Br= Diazoben- zene bromid. PYRIDIN BASES. These interesting substances, closely related to the vegetable alkaloids, as well as to some of the alkaloids produced during purtrefactive decomposition of animal matters, were first discov- ered in 1851, as constituents of oil of Dippel = oleum animale = oleum cornu cervi = bone-oil, an oil produced during the dry distillation of bones, horns, etc., and as a by-product in the manufacture of ammoniacal compounds from those sources. They also occur in coal-tar, naphtha, and in commercial ammonia, methylic spirit, and fusel oil. The pyridin bases at present known are : Formula. Boiling-point. Sp. gr. at 22*, Pyridin c6h5n il5° 0.924 Picolin c,h7n 134’ 0.933 Lutidin C7HUN 154° 0.945 Collidin CeHnN 170° 0.953 Parvolin CaHi3N 188’ 0.966 Coridin C,oH15N 211° 0.974 Rubidin CuHnN 230’ 1.017 Yiridin c12h19n 251’ 1.024 It will be observed that these compounds are inetameric with the anilins, from which they differ in constitution, as shown by the structural formulae of picolin and anilin : nh3 I c / \ H—C C—H I II H—C C—H / C I H c«h7n ch3 A / \ H—C C—H I II H—C C—H X / N C.HtN Anilin. Picolin. They are all liquid at the ordinary temperature, behave as tertiary monauiins, react with several of the general reagents of the alkaloids, and form chloroplatinates which are decomposed by boiling water. 416 MANUAL OF CHEMISTRY. y qtt CH\ Pyridin—HC^ch“ch/N—is obtained from oil of Dippel, and is also obtainable synthetically from piperidin, CHKctL—CH*/N—H’ wllich is itself a derivative of piperin, CJ2H90eN, a constituent of black and white pepper. It is a colorless, mobile liquid, having a peculiar, very penetrat- ing odor. It boils at 115° (239° F.). It mixes with water in all proportions. It is strongly alkaline, and combines with acids as does NH3. Like all the bases of this series, it is very stable, and withstands the action of such oxidizing agents as fuming HNOs and chromic acid. It forms crystalline salts. Parvolin, C0H13N; Collidin, C,H„N; and Hydrocollidin, C,H13N—have been noted as products of putrefactive decomposi- tion of albuminoids. /CH CH\ Pyrrol—~ CH/—*s a base accompanying the pyridin bases in oil of Dippel, and also obtainable from other sources. It is a colorless, oily liquid, whose odor resembles that of chloroform. By acting upon pyrrol with an ethereal solution of iodin, a quadrisubstituted derivative, tetriodopyrrol, C4HI4N, is obtained as a brown powder, which has been used under the name iodol as a substitute for iodoform in surgical practice. Furfurol—CriH ,0 ,—is also a condensation derivative of benzene, formed by the dry distillation of sugar, or by the action of Zn012 or dilute H2SO4 on bran. It is a colorless liquid, has an agreeable odor, boils at 162° (323°.6 F.), soluble in water and in alcohol. It is an aldehyde and undergoes the reactions common to those substances. ALCOHOLS 417 INCOMPLETE BENZENIC HYDROCARBONS. Series ChHjh-b and CnHaw—10. These may be considered as benzenic compounds which have been rendered incomplete by loss of Ha, either in the benzene nucleus or in a lateral chain. Thus while ethylbenzene is pro- duced by the addition of a molecule of ethylene to a molecule of benzene: CSH5,H + CH2,CHa = C8H5,CHa,CH3; if acetylene be substituted for ethylene, ethylenbenzene is formed : C«H5,H -+- CH,CH = C#H»,CH,CHa. Styrolene—Cinnamene—Ethylenbenzene—Phenylethene—Cr,H5 —CH = CH,—104—exists ready formed in essential oil of styrax. It is also formed by decomposition of cinnamic acid (q.v.), or, syn- thetically, by the action of a red heat upon pure acetylene, a mixture of acetylene and benzene, or a mixture of benzene and ethylene. It is a colorless liquid, has a penetrating odor, recall- ing those of benzene and naphthalene, and a peppery taste ; boils at 143° (289’.4 F.) ; soluble in all proportions in alcohol and water; neutral in reaction. Phenyl-acetylene—Acetenyl-benzene— CoH5,CLECH—is formed by heating acetophenone chlorid with KHO in alcoholic solution. It is a colorless liquid, of an aromatic odor, boils at 140° (284° F.). ALCOHOLS. Series CnH2n—«0. Cholesteric alcohol—Cholesterin—C2r,H i:iOH—373—is an alcohol, although usually classed by physiologists among the fats, because it is greasy to the touch and soluble in ether. It occurs in the animal economy, normally in the bile, blood (especially that coming from the brain), nerve-tissue, brain,spleen, sebum, contents of the intestines, meconium, and faeces ; patho- logically in biliary calculi, in the urine in diabetes and icterus, in the fluids of ascites, hydrocele, etc., in tubercular and cancer- ous deposits, in cataracts, in atheromatous degenerations, and sometimes in masses of considerable size, in cerebral tumors. It also exists in the vegetable world in peas, beans, olive-oil, wheat, etc. It is best obtained from biliary calculi, the lighter-colored varieties of which consist almost entirely of this substance. Cholesterin crystallizes with or without Aq ; from benzene, pe- troleum, chloroform or anhydrous ether, it separates in delicate, colorless, silky needles, having the composition C2eH440 ; from hot alcohol, or a mixture of alcohol and ether, it crystallizes in 418 MANUAL OF CHEMISTRY. rhombic plates, usually with one obtuse angle wanting, having the composition C20H44O + 1 Aq ; these crystals, transparent at first, become opaque on exposure to air, from loss of Aq. It is insoluble in water, in alkalies and dilute acids, difficultly soluble in cold alcohol, readily soluble in hot alcohol, ether, benzene, acetic acid, glycerin, and solutions of the biliary acids. It is odorless and tasteless. When anhydrous it fuses at 145 (293° F.) and solidifies at 137° (278°.6 F.) \ sp. gr. 1.046. It is lsevogvrous, [a]d = 31°. 6 in any solvent. It combines readily with the volatile fatty acids. From its so- lution in glacial acetic acid a compound having the composition C2gH440,C2H402 separates in fine curved crystals, which are de- composed on contact with water or alcohol ; when heated with acids under pressure, it forms true ethers. Hot HN03 oxidizes it to cholesteric acid, C.Hi0O6, which is also produced by the oxida- tion of biliary acids ; a fact which indicates the probable exist- ence of some relation between the methods of formation of cho- lesterin and of the biliary acids in the economy. Cholesterin may be recognized by the following reactions : (1.) Moistened with HN03, and evaporated to dryness, a yellow resi- due remains, which turns brick-red on addition of NH4HO. (2.) It is colored violet when a mixture of 2 vols. H2S04 (or HC1) and 1 vol. ferric chlorid solution is evaporated upon it. (3.) When H2S04 is added to a CHCi3 solution of cholesterin the liquid is colored purple-red, changing during evaporation to blue, green and yellow. Cholesterin is accompanied in wool fat by an isomere, isocho- lesterin. Cholesterin combines with the fatty acids to form ethers, cor- responding to the fats, and it probably exists in nature largely in such combination. Lanolin is a neutral, fatty body consisting of such cholesterids, or cholesterin ethers, obtained from suint, or wool fat. It is used as a vehicle in pharmacy, possessing two advantages over the fats and over vaseline : it is rapidly absorbed by the skin, and is miscible with water in all proportions. INDIGO GROUP. In this group are included a number of substances, derivable from indigo blue, which are evidently closely related to the ben- zene group, as is shown by the number of benzene derivatives which are obtained by their decomposition, but whose constitu- tion is not yet definitely established. Indigotin — Indigo-blue — Ci 6H, (>N202 — constitutes the greater part of the commercial indigo. It does not exist preformed in the plants from which it is obtained, whose juice is naturally INDIGO GROUP. 419 colorless, but is produced by decomposition of a glucosid con- tained in them (see Indican, p. 420). Indigotin may be obtained by the action of phosphorus tri- chlorid on isatin; or, in a nearly pure form, by cautiously sublim- ing commercial indigo. It forms purple-red, somewhat metallic, orthorhombic prisms or plates, odorless, tasteless, neutral, insol- uble in water, ether, or dilute acids or alkalies. By dry distilla- tion it yields anilin and other products. By moderate heating with dilute HN03 it gives off gas and is converted into isatin. Indigo Sulphonic Acids.—When indigo is heated for some time with fuming HaS04 it dissolves. If the solution be diluted with HaO, a blue powder, soluble in HaO, but insoluble in dilute acids, is precipitated. This is indigo-monosulphonic or phoenicin-sul- phonic acid—C,6HJNa0.iSC>;iH. The filtrate from the last-mentioned precipitate contains in- digo-disulphonic, sulphindylic, or sulphindigotic acid—C,,;H.N., O^SCbHh—whose Kand Na salts constitute soluble pastes known in the arts as soluble indigo, or indigocarmine. Isatin—C,H0NOa—obtained by oxidation of indigo-blue, forms shining, transparent, red-brown prisms. It is odorless, sparingly soluble in water, readily soluble in alcohol. Dioxindol—Hydrindic acid—CfiH7NOa—is formed by the action of Na on isatin suspended in HaO. It forms yellow prisms, solu- ble in HaO, and combines with both bases and acids. Oxindol—CbH-NO —is obtained from dioxindol by reduction with Na amalgam in acid solution. It crystallizes in easily solu- ble, colorless needles, and combines with acids and bases. Indol—C„H7N —is produced by distilling oxindol over zinc-dust, or by heating orthonitrocinnamic acid with KHO and Fe filings. It crystallizes in large, shining, colorless plates, having the odor of naphthylamin. It is a weak base, forming salts with acids, which are, however, decomposed by boiling water. Its aqueous solution, acidulated with HC1, is colored rose-red by KNOj. It is converted into anilin by fused KHO. It is one of the products of putrefaction of albuminoid sub- stances, and is formed during the action of the pancreatic secre- tion upon albuminoids. It is partly eliminated with the faeces and partly reabsorbed. In the intestine and faeces indol is invariably accompanied by Skatol, its superior homologue, which may also be ob- tained by the action of Sn and HC1 on indigo. It crystallizes in brilliant plates, and is less soluble than indigo. The product ob- tained from indigo has a penetrating but not disagreeable odor, while that obtained from putrid albumin and from faecal or in- testinal matter has a disgusting odor, probably due to the pres- ence of foreign substances. 420 MANUAL OF CJIEMISTKY. Indican—CsoH^NA—is a glucosid existing in the different va- rieties of indigo-producing plants, and also in the urine and blood of man and the lierbivora. It is a yellow or light brown syrup, which cannot be dried without decomposition, bitter and disagreeable to the taste, acid in reaction, and soluble in water, alcohol, and ether. It is very prone to decomposition. Even slight heating decom- poses it into leucin, indicanin, C2oH23NOia, and indiglucin, CcHi o06. A characteristic decomposition is that when heated in acid solu- tion, or under the influence of certain ferments (?), it is decom- posed into indigo-blue and indiglucin, the latter a glucose : 2C26HS1NO17 -+- 4Ha0 — C1BHioN»Oa + 6C6H10O0 Indican. Water. Indigotin. Indiglucin. DERIVATIVES OF TIIK PIIENYLMETHANES. 421 BI- AND POLYBENZOIC HYDROCARBONS. Among the compounds already considered are several contain- ing more than one benzene nucleus, but in them the union of the two nuclei, as in the azo compounds, is through an element other than carbon. In the compounds now to be considered two or more benzene nuclei are united with each other, either directly, or through the carbon of a linking lateral chain. HYDROCARBONS WITH INDIRECTLY UNITED BENZENE NUCLEI. The simplest of the bi- and polybenzoic hydrocarbons are those in which two or more benzene nuclei are combined with a linking lateral chain. By the substitution of phenyl for the H of methane four compounds can be produced : CeH5\p/H H/U\H CeHsXp/CeHs C6H5/°\H Monophenylmethane. Toluene. Triphenylmethane. C8H5\r/H CgHsXp/CfiHs CeH5/°\C6H. Of these the first has been already considered, and the fourth has not been isolated, although the corresponding ethane is known. Diphenylmethane—Benzyl-benzene—is produced by the action of aluminium chlorid upon a mixture of benzyl chlorid and ben- zene. It is a crystalline solid, fuses at 27° (80°. 6 F.) and boils at 262° (508°.6 F.); soluble in alcohol, ether and chloroform ; has an odor resembling that of the orange. Triphenylmethane—is produced by the action of aluminium chlorid upon a mixture of benzene and chloroform. It is a crystalline solid, fuses at 92° (197°.6 F.); boils at 3G0° (680° F.) ; soluble in ether, and in chloroform. It is converted into a tri- nitro derivative by fuming HN03, and this, in turn, is converted by nascent H into leuco-pararosanilin, CH,(CjH4,NH2)3 (see below). Diphenylmethane. Tetraphenylmethane. DERIVATIVES OF THE PHENYLMETHANES. Ketones—CO = (CnH2n—7)2.—These substances are similar to the phenones already described, but contain two benzene nuclei in place of one. They are produced by the oxidation of the liydro- 422 MANUAL OF CHEMISTRY. carbons CnEUw—14 ; by the action of P205 on a mixture of a hydrocarbon GnUm—e with an acid CnH2W—7CO,OH ; and by the action of carbon oxychlorid upon a hydrocarbon CnH2n—6 in the presence of A12C16. Benzophenone — Diphenyl-ketone — CO = (CfiHr,)2 — forms large rhombic prisms ; fuses at 48° (118°.4 F.); boils at 305° (581° F.) ; insoluble in H20, soluble in alcohol and ether. It is decomposed by soda-lime into benzene and benzoic acid. Sodium amalgam converts it into benzhydrol, or diphenylcarbinol, CH(OH) = (CcH5)2, a secondary alcohol. Amido-derivatives.—Among these substances are included some of great industrial interest. Many of the bases, whose salts are the brilliant pigments obtained from anilin and its homologues, are amido-derivatives of triphenylmethane. Amido-triphenylmethane—CH.(C6H5)2(CfiH4NH2)—is formed by the action of benzhydrol upon anilin chlorid in the presence of ZnCla. Diamido-triphenylmethane — CH.(C,;H6)(Cr1H4,NH2)3 — is pro- duced by the action of anilin chlorid and benzoic aldehyde upon each other in the presence of ZnCl2. The salts of this base are blue, and are decomposed by alkalies with liberation of the base, which is a yellow, imperfectly crystalline solid, insoluble in water, soluble in benzene and in alcohol. The base is converted by HgCl2 into the corresponding tertiary alcohol, diamido-triphenyl carbinol, C(OH),(C6H6),(C6H4,N'H2)4, whose oxalate or chloro-zincate is malachite green. Triamido-triphenylmethane—CH(C6H4. NH2)3—may be obtained by the reduction of para-nitrobenzoic aldehyde by nascent hydro- gen, and is also known as paraleucanilin. By the action of oxi- dizing agents it is converted into a tertiary alcohol, pararosanilin, or triamido-triphenyl carbinol, which is the type of quite a number of important bodies, among which is rosanilin, or di- phenyltoluyl carbinol, whose chlorid or acetate is the brilliant red dye known as anilin red, magenta, fuchsine. The relation of these bodies to each other is shown by the following formulae : /C6H5 H—C—C6H6 \C8H6 /C6H5,NH2 H—O—C—CeH6,NHs \C6H5,NH2 Triphenylmethane. Triamidophenyl carbinol. Pararosanilin. /CBH4,NHa H—C—C6H4,]N’H2 \C6H4,NH2 /c«h5,nh2 H—O—C—C6H6,1NtH2 \C6H4,CH3,NH2 Triamidophenylmethane. Paraleucanilin. Diamidophenyl amidotoluyl carbinol. Rosanilin. HYDROCARBONS WITH BENZENE NUCLEI. The rosanilins are powerful triacid bases, are colorless, but combine with acids to form brilliantly colored salts. Fuchsine is industrially obtained from “ anilin oil,” which contains both anilin and toluidin, neither of which in the pure state will pro- duce a red color. The process consists essentially in heating the oil with a mixture of nitro-benzene, hydrochloric acid and iron filings. The product is a mixture of the chlorids of rosanilin and pararosanilin, is in hard, green crystals, soluble in water and al- cohol, to which it communicates a brilliant red color. The rosanilins are capable of further modification by the sub- stitution of various radicals for the hydrogen atoms in the ben- zene nuclei, or in the groups NH2, and by variations in the posi- tions in which such substitution occurs. Hoffman’s violet, obtained by heating rosanilin chlorid with methyl iodid, is trimethylrosanilin chlorid. By a further action of methyl iodid, a brilliant green, iodin green, pentamethylrosan- ilin chlorid, is produced. Lyons blue is triphenylrosanilin chlorid, formed by heating rosanilin chlorid with excess of anilin. HYDROCARBONS WITH DIRECTLY UNITED BENZENE NUCLEI. These hydrocarbons and their derivatives are divided into two classes : 1. Those in which two or more benzene nuclei, each re- taining its six C atoms, are attached together by loss of Ha. 2. Those in which two or more benzene nuclei are united in such manner that each two possess two atoms of carbon in common, as shown in the formulae of naphthalene and phenanthrene given below. H H H H c—c c—c / X / X Diphenyl—HC C—C CH—is the simplest compound X / \ / c=c c=c H H H H of the first class. It is obtained by the action of sodium upon monobroinobenzene, or by passing benzene through a red-hot tube. It crystallizes in large plates, fusible at 70°.5 (159°.8 F.); boils at 254° (489°.2 F.). Diphenyl and its superior homologues, ditoluyl, diphenylbenzene, etc., constitute the nuclei of a great number of products of substitution, formed by the replacement of one or more of their H atoms by various radicals and elements, among them being many isomeres produced by differences of orientation. Phenanthrene—Ci4H,„—isomeric with anthracene (q.v.), may be 424 MANUAL OF CHEMISTRY. considered as a diortho-derivative of diphenyl, or as produced by the fusion of three benzene nuclei, the intermediate one of which has two C atoms in common with each of the extremes : CH = CH / \ CH—C C—CH HC7 %C—(/ XCH \ / \ / CH = CH CH = CH It crystallizes in brilliant, colorless plates, fusible at 99° (210°.2 F.), boils at 340° (044° F.), and sublimes readily at lower tempera- tures. Soluble in hot alcohol, and in cold benzene and ether, the solutions having a distinct blue fluorescence. It accompanies anthracene in the crude product. It is formed synthetically. Oxidizing agents convert it into phenanthroquinone, (CcH4)2(CO)2. Naphthalene—C,0H„—128—is the simplest compound of the second class (see above). It occurs in coal-tar. It has been formed by a synthesis which indicates its constitution. Benzene and ethylene, when heated together, unite to form, first, cinnamene and afterward naphthalene. It is constituted by the fusion of two benzol groups by two C atoms, thus : H H I I /°\A H—C C C—H I I! I H—C C C—H Xc/Xc/ I I H H It crystallizes in large, brilliant plates ; has a burning taste and a faint aromatic odor; fuses at 80° (176° F.) and boils at 217° (422°.6 F.), subliming, however, at lower temperatures ; burns with a bright, smoky flame ; insoluble in water, soluble in alcohol, ether, and essences. It forms substitution compounds with Cl, Br, I, HNOs, and H2SO<. SUBSTITUTION DERIVATIVES OF NAPHTHALENE. By the replacement of the hydrogen atoms of naphthalene by other atoms or by radicals, substitution products are obtained somewhat in the same manner as in the case of benzene (see pp. 391-394). In the case of naphthalene, however, the number of isomeres is much greater than with benzene. In the structural SUBSTITUTION DERIVATIVES OF NAPHTHALENE. 425 H(o) H (a) I I 8 1 C G /\(a?)/\ (/3)H—7C C C3—HO3) 1 11 I 0?) H—6C C C3— H03) \/(y)\/ C G 5 4 H(a) H(a) formula of naphthalene the positions 1, 4, 5, 8, although equal to each other, are of different value from the positions 2, 3, 6, 7, also equal to each other, as they are differently disposed with regard to the carbon atoms x and y. There exist, therefore, two possible unisubstituted derivatives of naphthalene for a single such de- rivative of benzene, etc. If the substituted group occupy the approximate positions. 1, 4, 5, or 8, it is called an a-derivative ; if it occupy the remote positions 2, 3, 6, or 7, it is a Naphthols—Ci„H7,OH—of which there are two : a-Naphthol has been obtained by heating plienyl-isocrotonic acid ; also by boiling an aqueous solution of diazonaphthalene nitrate with nitrous acid, or by fusing a-naphthalene-sulphonic acid with KHO. It crystallizes in colorless prisms ; fuses at 94D (201°.2 F.); boils at 280° (536° F.); is nearly insoluble in water, but soluble in alco- hol and in ether, and gives a transient violet color with FeaCl6 and a hypochlorite. fi-Naphthol=Isonaphthol—Hyclronaphthol—is prepared indus- trially by fusion of /3-naphthalene sulphonate of sodium with NaHO, for the manufacture of a number of coloring matters, among which are Campobello yellow and tropeolin. The com- mercial product is in reddish-gray, friable, light masses. The pure substance forms colorless, silky, crystalline plates, having a faint, phenol-like odor, and an evanescent, sharp, burning taste. It fuses at 123d (253 .4 F.), boils at 286° (514°.8 F.), and is sparingly soluble in water, but readily soluble in alcohol and ether. Its aqueous solutions are not colored violet by FeaCls. The pure substance is a valuable antiseptic. Naphthylamins — Amidonaphthalenes — C10H7.NH..—Two are known, corresponding in constitution to the naphthols. The a modification is formed by the reduction of a-nitronaphthalene. It crystallizes in flat needles, fuses at 50° (122° F.), boils at 300° (572c F.), insoluble in water, soluble in alcohol and ether. Has a disagreeable and persistent taste. The /3-naphthylamin is produced by the action of ammonia on 426 MANUAL OF CHEMISTRY. /3-naplithol at 150°-1G0° (302°-320° F.). It forms crystalline plates, fusible at 112° (233°.6 F.), boils at 294° (561°.2 F.) ; dissolves in hot H20, forming a blue fluorescent solution. Both forms are monacid bases, and form crystalline salts. Compounds of addition are obtainable from naphthalene as well as products of substitution. They are produced by the free- ing of one or more of the double bonds in the positions 1—2 ; 3—4 ; 5—6 and 7—8. Among these products is tetrahydro /Inaphthyl- amin, C10H7,H4NH2, a very active mydriatic. CHINOLIN BASES. The bases of this group at present known are: Chinolin C9H7N Pentahyrolin Ci3Hi6N Lepidin Ci0H9N Isolin CnHnN Cryptidin CnHuN Ettidin CisHjgN Tetrahyrolin C12Hi3N Validin Ci6H2iN CibHioN These bodies, which are closely related to the vegetable alka- loids, bear the same relation to naphthalene that the pyridin bases do to benzene, as will be understood by comparison of the following formulae: H H I C C / \ / \ HC C CH I 11 I HC C CH \ / \ / c c H H Ha Hp i c iSHC7 XC7 XCHm i B || Py | /3HC C CHo \ / \ / C N Ha Naphthalene. Chinolin. with those of anilin and picolin given on p. 415. As the molecule of naphthalene may be considered as produced by the fusion of two benzene nuclei, so chinolin may be regarded as resulting from the union of a benzene with a pyridin nucleus. They are obtained by the destructive distillation of the cin- chonin, quinin, and other natural alkaloids, to which they are closely related. Chinolin—C„H7N—is a mobile liquid; boils at 238° (460°.4 F.); becomes rapidly colored on contact with air. It has an intensely bitter and acrid taste, and an odor somewhat like that of bitter almonds. It is sparingly soluble in water, readily soluble in al- cohol and ether. Chinolin is the nucleus of a vast number of products of substi- tution, among which are many isomeres, due to differences in CIIINOLIN BASES. 427 orientation, according as the substitution occurs in the ortho, meta or para positions in the pyridin group Py (see formula above) or in the a or (3 positions in the benzene ring B. A few of these derivatives are of considerable medical impor- tance. Th.sHlin.=Tetrahydroparachinanisol—CmH, ,N0—is a derivative of the paramethyl ether of chinolin. It is met with in the form of sulphate and tartrate in the shape of crystalline powders. The odor of the sulphate is similar to that of anisol (methyl phenate); that of the tartrate to that of coumarin. The taste of both is bitter, acrid, and salty. Both salts are readily soluble in H20, the sulphate the more readily. Solutions of thallin salts assume, even when very dilute, a magnificent emerald-green color with Fe2Cl6 solution. A similar color is produced by AuC13 and by AgN03. Ethylthallin—C, 2H, TN0—is a derivative of thallin, whose clilorid is hygroscopic; readily forming solutions which are acid in reac- tion, bitter in taste; and assume a red-brown color with Fe2Cl6. Antipyrin = Phenyl-dimethyl-pyrazolon — C, ,H12N'20 — is ob- tained by heating phenyl-methyl-pyrazolon with methyl iodid and methyl alcohol in sealed vessels at 100° (212° F.); the first- named substance having been previously obtained by the action by acetylacetic ether upon phenyl bydrazin. It constitutes a voluminous, reddish, crystalline powder; read- ily soluble in water, ether, alcohol, and chloroform. With nitrous acid, or the nitrites (sp. feth. nitr.) in the presence of free acids, it forms a green, crystalline, sparingly soluble nitro-derivative which seems to be poisonous. Its solution with Fe2Cl8 is colored deep red-brown, the color being discharged by H2S04. Nitrous acid colors dilute solutions of antipvrin a bright green, which persists for several days at the ordinary temperature. If the mixture be heated, and a drop of fuming HN03 added, the color changes to light red, then blood- red, and the liquid deposits a purple oil on continued heating. Addition of a drop of fuming HN03 to a cold concentrated solu- tion of antipvrin produces precipitation of small green crystals. Kairin—Jfethyloxy chinolin hydrid—CulHi,NO—is more nearly derived from chinolin than the substances previously mentioned. Its eWorld is a crystalline, nearly white, easily soluble powder, whose taste is at once bitter, aromatic, and salty. Thallin, ethylthallin, antipyrin, and kairin are possessed of antiperiodic and antipyretic properties. 428 MANUAL OF CHEMISTRY. ANTHRACENE GROUP. Series CnH2n—18. Anthracene—C14H10—178—exists as a constituent of coal-tar, and is obtained by expression from the substance remaining in the still after the distillation of naphthalene, etc. The commer- cial product thus obtained is a yellowish mass containing 50-80 per cent, of anthracene, the purification of which is a matter of considerable difficulty. It has also been obtained synthetically, by the action of the heat on benzyl toluene, and in other ways. When pure, anthracene crystallizes in.rhombic tables having a bluish fluorescence; fusible at 210° (410° F.) and boiling above 360° (680° F.); its best solvents are benzene and carbon disulphid, in which, however, it is only sparingly soluble. The constitution of anthracene is that of two benzene nuclei united through two of their C atoms by the group=CH—CH= ; H(a) H(a) p H(cc) ii /K 1 /cx (/?) H—C C—C—C C—H (/3) I II I II I (/?) H—C C—C—C C—H (/3) \ / I \c> | H(y) y H(a) H(a) Oxidizing agents convert anthracene into anthraquinone. Re- ducing agents decompose it into three hydrocarbons,C14H30, CiHi6, and an oily hydrocarbon boiling above 360° (648° F.). Br and Cl at- tack it violently, I more slowly, forming products of addition. DERIVATIVES OF ANTHRACENE. As may be inferred from the complex molecule of anthracene, the number of possible derivatives of substitution and of addi- tion, including many isomeres, is very great. Anthraphenols—CnH»(OH).—Three are known, a and j3 anthrol, and anthranol. The two former are produced by the substitution of OH for one of the H atoms a or ft (see formula above) in anthra- cene, the latter by the substitution of the same group in the posi- tions x or y. Anthraquinone— CflH,—is formed by oxidation of anthracene. It forms yellow needles, which fuse at 273° (523°.4 F.). It is not easily oxidized, but is converted into anthracene by suf- ficiently active reducing agents. DERIVATIVES OE ANTHRACENE. 429 Dioxyanthraquinone—Alizarin—C6H, C«H. —is the red pigment of the madder root (Rubia tinctoria). Artificial alizarin has now almost completely displaced the natural product in dyeing. It is obtained by the action of fused KHO on many anthracene derivatives, the one generally used being anthra- quinone-disulphonic acid, Ci ,H,;0..(S0;iH)2. Methylanthracene—Ci tH ,,CH3—is obtainable by synthesis, and also by heating chrysophanic acid, emodin, or aloin with zinc- dust. Crysophanic Acid—Parietic Acid—Rheic acid—Rhein—Ci 5Hi 0O4 —is a derivative of methylanthracene, which exists in the lichens Parmelia parietina and Squamaria elegans, in senna, and in rhubarb, and obtainable to the extent of 80 per cent, from Qoa powder—Chrysarobin, C3oH3607. Chrysophanic acid crystallizes in golden, orange-yellow, inter- laced needles. It is almost tasteless and odorless; fuses at 162° (291°. F.); almost insoluble in cold water, sparingly soluble in hot water, alcohol, and ether, readily soluble in benzene. It forms a red solution with HaSCh, from which it is deposited unchanged by water. It also forms red solutions with alkalies. Reducing agents convert it into methylanthracene. Trioxymethylanthraquinone — Emodin — CnHi(CH3)(OH)3Oi — occurs in the bark of Rhamnus frangula, and accompanies chry- sophanic acid in rhubarb. It crystallizes in long, orange-red prisms which fuse at 250° (482° F.), and yield methylanthracene when heated with zinc-dust. 430 MANUAL OF CHEMISTKY. TEREBENTHIC SERIES. In this series are included a number of isomeric hydrocarbons, having the formula Ci0Hi6, or a simple multiple thereof, and their products of derivation. The hydrocarbons are in some cases arti- ficial products, but for the most part exist in nature in the differ- ent turpentines, and volatile oils, or essences. When liquid they are called terpenes, when solid camphenes. Turpentine—Terebenthina (U. S.)—is the common American turpentine, obtained from incisions in bark of Pinus palustris and P. tazda, and may be taken as the type of many similar prod- ucts obtained from other plants. It is a yellowish-white semi- solid, having a balsamic odor, which is divided by distillation into two products. One a liquid, an eloeoptene : oil, or essence of turpentine; the other a solid, a stearoptene : rosin, or colophony. The liquid product so obtained, oil of turpentine, in the case of the American product consists chiefly of a hydrocarbon, CmHie, called australene, and in the case of the French turpentine of an isomeric body, called terebenthene. These two bodies are obtained from the oils of turpentine by mixing with an alkaline carbonate and subjecting them to frac- tional distillation in vacuo over the water-bath. The differences between them are principally in their physical properties. Aus- tralene is dextrogyrous, (a)D=17°, boils at about 155° (311° F.). Tere- benthene is lsevogvrous, (d)v>——40°.32, boils at 156°.5 (313°.7 F.), sp. gr. 0.864 at 16° (60°.8 F.). They are colorless, mobile liquids; have the peculiar odor of turpentine; burn with a smoky, luminous flame. They absorb oxygen rapidly from the air, whether pure or in the commercial essence, becoming thick, and finally gummy. Oxidizing agents, such as HN03, attack them energetically, caus- ing them to ignite and burn suddenly, with separation of a large volume of carbon. HC1 unites with them to form a number of com- pounds,as do also III and HBr—all the compounds having the odor of camphor. When mixed with HN03, diluted with alcohol, and exposed to the air, they form terpin hydrate. Cl, Br and I form compounds of substitution or of addition. Oil of turpentine may be boiled without suffering decomposi- tion, but if heated under pressure at 250°-300° (482°-f)72° F.) the terpene is converted into two products, one liquid, boiling at 177’ (350°.6 F.), isomeric with the terpene, called isoterebenthene ; the other viscous, boiling at about 400° (752° F.), polymeric with the first, C20II32, called metaterebenthene. Sulphuric acid acts violently upon oil of turpentine when the two liquids are agitated together, and the latter yields a number of isomeric and polymeric derivatives. After standing 24 hours TEKEBENTHIC SERIES 431 the mixture separates into two layers. If the upper layer be dis- tilled at about 250° (482 F.) it yields a mobile liquid, which, when purified by contact with dilute and then with solution of NaHO, and dried and subjected to fractional distillation, may be separated into (1) Terebene, C,„H16, a colorless, mobile liquid, having a faint odor, optically inactive, boiling at 156° (312°.8 F.); (2) cymene; (3) a number of polymeres of terebenthene, among which is Colophene, or Diterebene, C20H,a, a colorless oil, having a brilliant, indigo-blue fluorescence; boils at 300 -315° (572°-5995 F.); sp. gr. 0.91 at 4° (39 .2 F.). There exist a number of hydrates of the terpenes: Terpinol— 2(CiuHib),H20—produced by distilling terpin (see below) with very dilute H2S04, or terpene monochlorhydrate with H20, or alcohol. It is a colorless liquid, having the odor of hyacinth, boiling at 168° (234°.4 F.); sp. gr. 0.852. Terpene hydrate—Ci„Hir,,HjO—formed by distilling terpin with HC1; or by allowing French oil of turpentine to remain for some days in contact with alcohol and H2S04. It is an oily liquid, boils at 210°-214° (410°-417°.2 F.), suffering partial decomposition. Terpin—Cn.HmjSHjO—is formed by the dehydration of terpin hydrate (q.v.). It is crystalline, fusing at 103° (217°.4 F.), capable of sublimation, and boils at about 250° (482 F.). It absorbs H20 eagerly to form terpin hydrate. It behaves like a diatomic al- cohol, and is converted into terebenthene dichlorhydrate, by gas- eous HC1, or by PCU. It is dehydrated by P205, and converted into terebene and colophene. Terpin hydrate—Ci0H16,3H2O—formed when oil of turpentine remains for a long time in contact with H20, the formation being favored by the presence of a mixture of alcohol and dilute HNG3. It exists in large, colorless, prismatic crystals, odorless, fuses at about 100° (212° F.), sparingly soluble in H20, soluble in alcohol and in ether. It readily gives up H20 in dry air at 100° (212° F.), and is then converted into terpin. The Camphenes are solid, crystalline bodies, having odors re- sembling that of camphor, formed by the action of the Na salts of weak acids, at 200°-220° (392°-428° F.) upon the monochlorhy- drates of the corresponding terebenes. 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 solu- ble in water, more or less soluble in alcohol and ether; colorless or yellowish, inflammable, and prone to become resinous on ex- posure to air. They are not simple chemical compounds, but 432 MANUAL OF CHEMISTRY. mixtures, and in many of them the principal ingredient is a hy- drocarbon, isomeric with terebenthene, and consequently having the composition nCioHi*. Some contain hydrocarbons, others al- dehydes, acetones, phenols, and ethers. Of the numerous other hydrocarbons closely related to tereben- thene, but two require further consideration as being the princi- pal constituents of caoutchouc and gutta-percha. Caoutchouc—India-rubber—is a peculiar substance existing in suspension in the milky juice of quite a number of trees growing in warm climates. It is, when pure, a mixture of two hydrocar- bons—caoutchene, Ci0Hi6, and isoprene, C;H„. 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 H20 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 disul- phid, either alone, or, better, mixed with 5 parts of absolute al- cohol. It is not acted upon by dilute mineral acids, but is attacked by concentrated HN03 and H2S04, 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, depriving it of its elasticity, and ren- dering it hard and brittle. When heated it becomes viscous at 145° (298° F.), and fuses at 170°-180° (347°-356° 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, burning with a reddish, smoky flame, which Is extinguished with difficulty. 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 130o-150° (2(>6°-302° F.). Ordinary vulcanized rubber differs mate- rially from the natural gum in its properties; its elasticity and flexibility are much increased; it does not harden when exposed 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 certain 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-con- TEREBENTHIC SERIES. 433 ductor of electricity. It contains 20 to 35 per cent, of S (the ordi- nary vulcanized rubber contains 7 to 10 per cent.). Gutta-percha—is the concrete juice of Isonandra yutta. It is a tough, inelastic, brownish substance, having an odor similar to that of caoutchouc; when warmed it becomes soft and may be moulded, or even cast, so as to assume any form, which it re- tains on cooling; it may be welded at slightly elevated temper- atures, is a good insulating and waterproofing material. It is insoluble in water, alkaline solutions, dilute acids, including hydrofluoric, and in fatty oils; it is soluble in benzene, oil of tur- pentine, essential oils, chloroform, and especially in carbon disul- phid. A solution in chloroform is known as traumaticine, or Liq. gutta-perchae (U. S.), and is used to obtain, by its evaporation, a thin film of gutta-percha over parts which it is desired to pro- tect from the air. It is attacked by HN03 and H2SCh. When exposed to air and light, it is gradually changed from the surface inward, assuming a sharp, acid odor, becoming hard and cracked, and even a conductor of electricity. Gutta-percha seems to be made up of three substances: Gutta, C2oH39, 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, Cj(,Ha jO.., 14-19 per cent., a white, crystalline resin, heavier than water, fusible at 160 (320 F.); soluble in benzene, essence of turpentine, carbon disulphid, ether, chloroform, and hot absolute alcohol; not attacked by HC1. Fluviale, 4-6 per cent., C2oH320, 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.—The camphors are probably aldehydes or alcohols corresponding to hydrocarbons related to tereben- tliene, although their constitution is still uncertain. Common camphor—Japan camphor—Laurel camphor—Cam- pholic aldehyde—Camphora (U. S., Br.)—CiuHi60—152.—Three modifications are known, which seem to differ from each other only in their action upon polarized light: (1.) Dextro camphor= Camphora officinarum ; obtained from Lauras camphora—[a]D= +47°.4. (2.) Laevo camphor, obtained from Matricaria postla- nium—[«]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, translucent, crystalline solid; sp. gr. 0.980-0.996, hot and bitter in taste; aromatic; sparingly soluble in H20; quite soluble in ether, acetic acid, methylic and ethylic alcohols, and the oils; fuses at 1753 (347° F.); boils at 204° (399°.2 F.); sublimes at all temperatures. It ignites readily and burns with a luminous flame. Cold HN03 434 MANUAL OF CULM ISTRY. dissolves it, and from the solution H20 precipitates it unchanged. Boiling HA03, or potassium permanganate, oxidizes it to dextro camphoric acid, Cn,Hlc04. Concentrated H2S04 forms with it a black solution, from which H20 precipitates camphene. Distilled with P206, it yields cymene, CioHm. Alkaline solutions, by long heating under pressure, convert it into camphic acid, CU1HI(0,, and borneol. Cl attacks it with difficulty. Br unites with it to form an unstable compound, which forms ruby-red crystals, having the composition CioHi4OBr2. These crystals, when heated to 80°-90° (176°-194° F.), fuse and give off HBr, there remaining an amber- colored liquid, which solidifies on cooling, and yields, by recrys- tallization from boiling alcohol, long, hard, rectangular crystals of monobromo camphor—Camphora monobromata (U. S.)—C, 0H, ;,OBr. AVhen vapor of camphor is passed over a mixture of fused potash and lime, heated to 300c-400° (572°-752° F.), it unites directly with the potash to form the K salt of campholic acid, Cu,Hlh02. Borneol—Borneo camphor—Camphol—Camphyl alcohol—Ci0Hi8 0—154—is usually obtained from Dryobalanops camphora, al- though 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 deter- mine, 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 racetic 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. AVhen heated with P205, it yields a hydro- carbon. borneene, Ci„H1(i. Oxidized by HN03, it is converted into laurel camphor. Menthol—Menthyl alcohol—Ci„H20O—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 disulphid, and in acids. Corresponding to it are a series of menthyl ethers. Eucalyptol—Ci2H ,„0—180—is contained in the leaves of Euca- lyptus globulus ; it is liquid at ordinary temperatures, and boils at 175° (347° F.); by distillation with phosphoric anhydrid it yields eucalyptene, C12H18. Resins—are generally the products of oxidation of the hydro- carbons allied to terebenthene; are amorphous (rarely crystal- line); insoluble in water; soluble in alcohol, ether, and essences. Many of them contain acids. TEKEBENTIIIC SERIES. 435 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 tola. (2.) Oleo-resins consist of a true resin mixed with an oil, and usu- ally with an oxidised 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 lupulin. (3.) Gum-resins are mix- tures of true resins and gums. Many of them are possessed of medicinal qualities; aloes, ammoniac, asafcetida, bdellium, eu- phorbium, gaTbanum, gamboge, guaiac, myrrh, olibanum, opop- onax, and scammony. (4.) True resins are hard substances ob tamable 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. 436 MANUAL OF CHEMISTRY. COMPOUNDS OF UNKNOWN CONSTITUTION. GLUCOSIDS. Under this head are classed a number of substances, some of them important medicinal agents, which are the products of veg- etable or animal nature. Their characteristic property is that, under the influence of a dilute mineral acid, they yield glucose, phloroglucin or mannite, together with some other substance. Under the supposition that glucose and its congeners are alcohols, it is quite probable that the glucosids are their corresponding ethers. Amygdalin, C20H27NOu—457—exists in cherry-laurel and in bit- ter almonds, but not in sweet almonds. Its characteristic reac- tion is that, in the presence of emulsin, which exists in sweet as well as in bitter almonds, and of water, it is decomposed into glucose, benzoic aldehyde, and hydrocyanic acid. The same re- action is brought about by boiling with dilute HaSCh or HC1. Bitter almonds contain about 2 per cent, of amygdalin. Digitalin.—The pharmaceutical products sold under the above name, and obtained from digitalis, are mixtures in varying pro- portions of several glucosids. Digitonin, C31H6aOi7, an amorphous, yellowish substance, very soluble in aqueous alcohol. Digitalin, CoH.Oj, the principal constituent of the French digitalin, is a col- orless, very bitter, crystalline solid, insoluble in water, soluble in alcohol. Digitalein, a white, intensely bitter, amorphous solid, very soluble in water, soluble in alcohol. Digitoxin, C21H.O7, a colorless, crystalline solid, insoluble in water, sparingly soluble in alcohol. It is not a glucosid, and is converted into toxiresin by dilute acids. The Abstractum digitalis (U. S.) probably contains all the above, the extraction of the first being more complete with weak alcohol, that of the others with strong alcohol. Glycyrrhizin.—A non-crystallizable, yellowish, pulverulent prin- ciple, obtained from liquorice; soluble with difficulty in cold water, soluble in hot water, alcohol, and ether; bitter-sweet in taste. By long boiling Avith dilute acids it is decomposed into glucose and glycyrrhetin, C^H2(0,. Jalapin—C3JH560i6—720—is the acti\Te principle of scammony, and exists also to a limited extent in jalap (see below). It is an insipid, colorless, amorphous substance, which is decomposed by dilute acids into glucose and jalapinol. The active ingredient of jalap is not, as the name would imply, jalapin, but a resinous substance called convolvulin, which is insoluble in ether, odorless, COMPOUNDS OF UNKNOWN CONSTITUTION. 437 arid, insipid. It is not attacked by dilute HjSCh, although the concentrated acid dissolves it with a carmine-red color, slowly turning to brown; in alcoholic solution it is decomposed by gase- ous HC1 into glucose and convolvulinic acid. Q,uinovin—Q,uino vatic acid.—A bitter principle, possessed of acid functions, obtained from the false bark, known as Cinchona nova; it is a glucosid, being decomposed by dilute acids into a sugar resembling mannitan and quinovic acid. Salicin—Salicinum (TJ. S.)—Ci3Hlt.07—286—occurs in the bark of the willow (salix). It is a white, crystalline substance; insoluble in ether, soluble in water and in alcohol; very bitter, its solutions are dextrogyrous, [a]D = -4-65°.8. Dilute acids decompose it into glucose and saligenin (q.v.). Concentrated H2SO4 colors it red, the color being discharged on the addition of water. When taken into the economy it is converted into salicylic aldehyde and acid, which are eliminated in the urine. Santonin—Santo7iic acid—Santoninum (U. S., Br.)—Cif)HiPOa— 246.—A glucosid having distinct acid properties; obtained from various species of Artemisia. It crystallizes in colorless, rectan- gular prisms, which turn yellow on exposure to light; odorless and tasteless; insoluble in cold water, sparingly soluble in hot water, alcohol, and ether; its solutions are faintly acid in reac- tion. Santonin, in solution, gives a chamois-colored precipitate with the ferric salts, and a white precipitate with silver, zinc, and mercurous salts; no precipitate with mercuric salts. Patients taking santonin pass urine having the appearance of that containing bile, which, wrhen treated with potash, turns cherry-red or crimson, the color being discharged by an acid, and regenerated on neutralization. Solanin.—A glucosid, having basic properties, existing in differ- ent plants of the genus Solanum. It crystallizes in fine, white, silky needles; having an acrid, bitter taste; insoluble in water, and but sparingly soluble in ether and in alcohol. By the action of hot dilute acids it is decomposed into glucose and a basic sub- stance, solanidin. When not heated, solanin combines with acids to form uncrystallizable salts. Cold concentrated H2S04 colors it orange-yellow, and finally forms with it a brown solu- tion; HXOs dissolves it, the solution being at first colorless, after- ward rose-pink. Strophanthin—C20H3 ,0X 0—aglucosid from Stroph anthus Ko mbe, forms white, crystalline plates, bitter in taste, slightly soluble in water, more soluble in alcohol, insoluble in ether, carbon disulphid and benzene. Tannins—Tannic acid—CnHmO.,—322.—Quite a number of dif- ferent substances of vegetable origin, principally derived from barks, leaves, and seeds. They are amorphous, soluble in water, 438 MANUAL OF CHEMISTRY. astringent, capable of precipitating albumen, and of forming im- putrescible compounds with the gelatinoids. They are, with one possible exception, glucosids. Gallo-tannic acid—Acidum tannicum (U. S., Br.)—is the best known of the tannins, and is obtained from nut-galls, galla (U. S., Br.), which are excrescences produced upon oak trees by the puncture of minute insects. It appears as a yellowish, amor- phous, odorless, friable mass; has an astringent taste; very solu- ble in water, less so in alcohol, almost insoluble in ether; its solu- tions are acid in reaction, and on contact with animal tissues give up the dissolved tannin, which becomes fixed by the tissue to form a tough, insoluble, and non-putrescible material (leather). A freshly prepared solution of pure gallo-tannic acid gives a dark blue precipitate with ferric salts, but not with ferrous salts. If, however, the solution have been exposed to the air, it is altered by oxidation, and gives, with ferrous salts, a black color (in whose production gallic acid probably plays an important part), which is the coloring material of ordinary writing-ink. Caffetannic acid—exists in saline combination in coffee and in Paraguay tea. It colors the ferric salts green, and does not affect the ferrous salts, except in the presence of ammonia; it precipi- tates the salts of quinin and of cinchonin, but does not precipi- tate tartar emetic or gelatin. It is a glucosid, being decomposed by suitable means into eaffeic acid and mannitan. Cachoutannic acid—obtained from catechu, is soluble in water, alcohol, and ether. Its solutions precipitate gelatin, but not tartar emetic; they color the ferric salts grayish-green. Morintannic acid—Maclurin—a yellow, crystalline substance, obtained from fustic; more soluble in alcohol than in water. Its solutions precipitate green with ferroso-ferric solutions; yellow with lead acetate; brown with tartar emetic; yellowish-brown with cupric sulphate. It is decomposable into phoroglucin and protocatechuic acid. Quercitannic acid—is the active tanning principle of oak-bark; it differs from gallo-tannic acid in not being capable of conversion into gallic acid, and in not furnishing pyrogallol on dry distilla- tion. It forms a violet-black precipitate with ferric salts. The tannin existing in black tea seems to be quercitannic acid. Quinotannic acid—a tannin existing in cinchona barks, proba- bly in combination with the alkaloids. It is a light yellow sub- stance; soluble in water, alcohol, and ether; its taste is astringent, but not bitter. Dilute H2S04 decomposes it, at a boiling temper- ature, into glucose and a red substance—quinova red. ALKALOIDS 439 ALKALOIDS. The alkaloids are organic, nitrogenized substances, alkaline in reaction, and capable of combining.with acids to form salts in the same way as does ammonia. They are also known as vegetable or organic bases or alkalies, and are probably amins of complex constitution. The similarity between the relation of the free alkaloids to their salts and that of ammonia to the ammoniacal salts is shown in the following equations: 2NH3 + H3S04 = (NHd.SCb Ammonia. Sulphuric acid. Ammonium sulphate. 2C1TH19N03 + H3S04 = (C1,H30NO3)3SO4 Morphin. Sulphuric acid. Morphonium sulphate. Classification.—The natural alkaloids are temporarily arranged in two groups: (1.) Those which are liquid and volatile, and consist of C, H and N. The synthesis of one of their number shows that they are true amins. (2.) Those which are solid, crystalline, volatile with difficulty, if at all, and consist of C, H, N and O. No representative of this class has yet been obtained by synthesis. General Physical Characters.—As a rule they are insoluble, or nearly so, in water; more soluble in alcohol, chloroform, petro- leum-ether, and benzene. Their salts are, for the most part, sol- uble in water and insoluble or sparingly soluble in petroleum- ether, benzene, ether, chloroform, and amyl alcohol. All exert a rotary action on polarized light: Quinin [a] = —126°. 7 Quinidin a = +250". 75 Cinchonin [a = +190°.4 Cinchonidin ... . a = —144°.01 Morphin a = — 88°.4 Narcotin [a] = —103°. 5 Codein [a] = —118°.2 N arcein [a — — 6°. 7 Strychnin a = —182°.07 Brucin a — — 61°.27 Nicotin [a] = — 98°.5 Generally, combination with an acid diminishes their rotary power; with quinin the reverse is the case. Free narcotin is ljevogyrous; its salts are dextrogyrous. They are all bitter in taste. General Chemical Reactions.—Potash, soda, ammonia, lime, baryta, and magnesia precipitate the alkaloids from solutions of their salts. Phosphomolybdic acid forms a precipitate which is bright yel- low, with anilin, morphin, veratrin, aconitin, einetin, atropin, hyoscyamin, thein, theobromin, conil'n, and nicotin; brownish- 440 MANUAL OF CHEMISTliY. yellow with narcotin, codein, and piperin; yellowish-white with quinin, cinchonin and strychnin; yolk-yellow with brucin. The reagent is prepared as follows: Ammonium molybdate is dissolved in H20, the solution filtered, and a quantity of hydro- disodic phosphate £ in weight of the molybdate used is added, and then HN03 to strong acid reaction. The mixture is warmed; set aside for a day; the yellow ppt. collected on a filter; washed with HoO acidulated with HN03; and while still moist transferred to a porcelain capsule, to which the liquid obtained by exhaust- ing the remainder on the filter with NH4HO is added. The fluid is warmed and gradually treated with pulverized sodium carbon- ate until a colorless solution is obtained. This is evaporated to dryness; a small quantity of sodium nitrate is added, and the whole gradually heated to quiet fusion and until all NH3 is ex- pelled. The residue is dissolved in warm H20 (1 to 10), acidulated with HN03, and decanted. To use the reagent, a drop of the suspected liquid is placed on a glass plate with a black background, and near it a drop of the reagent; and the two drops are made to mix slowly by a pointed glass rod. Potassium iodhydrargyrate gives a yellowish precipitate with alkaloidal solutions which are acid, neutral, or faintly alkaline in reaction. The reagent is obtained by dissolving 13.546 grams of mercuric chlorid and 49.8 grams of potassium iodid in a litre of water. The solution may be used for quantitative determinations. The reagent is added from a burette to the solution of alkaloid until a drop, filtered from the solution which is being tested, and placed upon a black surface, gives no precipitate with a drop of the reagent. Each c.c. of reagent used indicates the presence in the volume of liquid tested of the following quantities of alka- loids, in grams: Aconitin 0.0267 Atropin 0.0145 Narcotin 0.0213 Strychnin 0.0167 Brucin 0.0233 Veratrin 0.0269 Morphin ..... 0.0200 Coniin 0.00416 Nicotin 0.00405 Quinin 0.0108 Cinch onin 0.0102 Quinidin 0.0120 Of course, the process can be used only in a solution containing a single alkaloid. Separation of Alkaloids from Organic Mixtures and from Each Other.—One of the most difficult of the toxicologist’s tasks is the separation from a mixture of organic material (contents of stom- ach, viscera) of an alkaloid in such a state of purity as to render its identification perfect. The difficulty is the greater if the amount present be small, as is usually the case; and if the search be not confined to a single alkaloid, as frequently occurs. Some of these substances, as strychnin, are detectable with much greater facility and certaintv than others. ALKALOIDS. 441 Of the processes hitherto suggested, the best is that of Dragen- dorff, devised for the detection of any alkaloid or poisonous or- ganic principle present in the substances examined. It is very exhaustive, and well adapted to cases frequently arising in chemico-legal practice; but, on the other hand, is too intricate to be serviceable to the general practitioner. An abridgement of this process may be of use to detect the j>resence of the more commonly used alkaloids in a mixture of organic material. The physician should, however, bear in mind that, in cases liable to give rise to legal proceedings, these may become seriously complicated by the analysis of any parts of the body, dejecta, or suspected articles of food, etc., by any process open to attack by the most searching cross-examination. The substances to be examined are reduced to a fine state of subdivision, and are digested for an hour or more in water acid- ulated with H2SO4, at a temperature of 40° to 50 (104°-122° F.): this is repeated three times, the liquid being filtered and the solid material expressed. The united extracts are evaporated at the temperature of the water-bath to a thin syrup; this is mixed with three or four volumes of alcohol, the mixture kept at about 35' (1)5° F.) for 24 hours, cooled well and filtered; the residue being washed with seventy per cent, alcohol. The alcohol is distilled from the filtrate, and the watery residue diluted with H20 and filtered. The filtrate so obtained contains the sulphates of the alkaloids, and from it the alkaloids themselves are separated by the follow- ing steps: A. The acid watery liquid is shaken with freshly rectified petroleum-ether (which should boil at about 05 -70 (149°-158° F.), and should be used with caution, as it is very inflammable); after several agitations the ether layer is allowed to separate and is removed; this treatment is repeated so long as the ether dissolves anything. The residue obtained by the evaporation of the ether —Residue I.—is mostly composed of coloring matters, etc., which it is desirable to remove. B. The same treatment of the watery liquid is repeated with benzene, which on evaporation yields Residue 11., which is, if crystalline, to be tested for cantharidin, santonin, and digitalin (q.V.)\ if amorphous, for elaterin and colcliicin. C. The acid, aqueous fluid is then treated in the same way with chloroform to obtain Residue III., which is examined for cinchonin, digitalin, and picrotoxin by the proper tests. D. The watery fluid, after one more shaking with petroleum- ether and removal of the ethereal layer, is rendered alkaline with ammonium hydrate and shaken with petroleum-ether at 40' (104' F.), the ethereal layer being removed as quickly as possible while still warm; this is repeated two or three times, and repeated with cold petroleum-ether, which is removed after a time. The warm ethereal layers yield Residue IV. a ; the cold ones Residue W . b. The former is tested for strychnin, quinin, brucin, veratrin; the latter for conii'n and nicotin. E. The alkaline, watery fluid is shaken with benzene, which, on evaporation, yields Residue V., which may contain strychnin, 442 MANUAL OF CHEMISTRY. brucin, quinin, cinchonin, atropin, hyoscyamin, physostigmin, aconitin, codeln, thebal'n, and narceln. F. A similar treatment with chloroform yields Residue VI., which may contain a trace of morphin. Gr. The alkaline liquid is then shaken with amyl alcohol, which is separated and evaporated; Residue VII. is tested for morphin, solanin, and salicin. H. Finally, the watery liquid is itself evaporated with pounded glass, the residue extracted with chloroform, and Residue VIII., left by the evaporation of the chloroform, tested for curarin. Volatile Alkaloids. Coniin—Conicin—Cicutin—C8H,5N—125—is obtained from Co- ilium maculatum, in which it is accompanied by two other alka- loids, methyl-coniin, CBH14N(CH3), and conhydrin, CuH17NO—the former a volatile liquid, the second a crystalline solid. Coniin is a colorless, oily liquid; has an.acrid taste and a dis- agreeable penetrating odor; sp. gr. 0.878; can be distilled when protected from air; boils at 212° (418°. G F.); exposed to air it resin- ifies; it is very sparingly soluble in water, but is more soluble in cold than in hot water; soluble in all proportions in alcohol, sol- uble in six volumes of ether, very soluble in fixed and volatile oils. The vapor which it gives off at ordinary temperatures forms a white cloud when it comes in contact with a glass rod moistened with HC1, as does NH3. It forms salts which crystallize with difficulty. Cl and Br combine with it to form crystallizable com- pounds; I in alcoholic solution forms a brown precipitate in alcoholic solutions of conil'n, which is soluble without color in an excess. Oxidizing agents attack it with production of butyric acid (see below). The iodids of ethyl and methyl combine with it to form iodids of ethyl- and methyl-conium. It has been ob- tained synthetically by first allowing butyric aldehyde and an alcoholic solution of ammonia to remain some months in contact at 30° (86° F.), when dibutyraldin is formed: Butyric aldehyde. 2(C4H,0) + nh3 = c,hI7no + h2o Ammonia. Dibutyraldin. Water. The dibutyraldin thus obtained is then heated under pressure to 150°-180° (302°-356° F.), when it loses water: Dibutyraldin. C8HitNO = CsHj.N + H20 Coniin. Water. A synthesis which, in connection with the decompositions of (C4HO' ) coniin, shows its rational formula to be (C4H7) > N. H ALKALOIDS. 443 Analytical Characters.—(1.) With dry HC1 gas it turns reddish-purple, and then dark blue. (2.) Aqueous HC1 of sp. gr. 1.12 evaporated from coniln leaves a green-blue, crystalline mass. (3.) With iodic acid a white ppt. from alcoholic solutions. (4.) With HaSO* anil evaporation of the acid: a red color, changing to green, and an odor of butyric acid. (5.) When mixed with commercial nitrobenzene a fine blue color is produced, changing to red and yellow. Nicotin—Ci,,HhNs—1(52—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 lumin- ous 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. Analytical Characters.—(1.) Its ethereal solution, added to an ethereal solution of iodin, separates a reddish-brown, resi- noid oil, which gradually becomes crystalline. (2.) With HC1, a violet color. (3.) With HN03, an orange color. Both nicotin and coniTn are actively poisonous, producing death by asphyxia, sometimes as rapidly as prussic acid. Spartein—CisH^N,!—a colorless oil, whose odor resembles that of anilin; extremely bitter in taste; sparingly soluble in water, forming an alkaline solution. On exposure to air becomes brown and resinous. 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 character of the plants from which they are derived. Opium Alkaloids.—Opium is the inspissated juice of the cap- sules of the poppy. It is of exceedingly complex composition, and contains, besides a neutral body called meconin (probably a poly- atomic alcohol, CioHioOj), 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, however, 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: 444 MANUAL OF CHEMISTRY. Name. Formula. Per Cent, in Smyrna Opium. Per Cent, in Constanti- nople Opium * Meconic acid C-H.O, 4.70 4.38 Lactic acid C-iHoOs 1.25 Meconin C]oHioO< 0.08 0.30 * Morphin C17H19NO3 10.30 4.50 Pseudomorphin C,-H19N04 Hydrocotarnin ... * Codel'n CuHieNOs Ci8H21N03 6125 L52 * TliebaYn Gi.HsiNOi 0.15 Protopin Rhaeadin CaoHigNOs C20H21NO6 Codamin C20H25NO4 Tifl.ii danin C20H25N O4 Papaverin CS1H2lN04 1.00 Opianin C21H2.N0, Meconidin C2.HasN04 Cryptopin C2.H23N05 Laudanosin C2.H27N04 * Narcotin C22H23NOT i .30 3.47 Lanthopin C23H25N04 * NarceTn C23H2.N0. 0.71 0.42 Morphia.—Morphina (U. S.)—CnHi9N03+Aq—285+18—crystal- lizes in colorless prisms; odorless, but very bitter; it fuses at 120a (248° F.), losing its Aq. More strongly heated, it swells up, be- comes carbonized, 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 boiling 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; rather more soluble in alcoholic ether; almost insoluble in benzene; soluble in GO pts. of chloroform. All the solvents dissolve morphin more readily and more copiously when it is freshly precipitated from solutions of its salts than when it has assumed the crystalline form. Morphin combines 'with acids to form crystallizable salts, of which the chlorid, sulphate, and acetate are used in medicine. If morphin be heated for some hours Avith excess of HC1, under pressure, to 150° (302° F.), it loses water, and is converted into a neAV base—apomorphin. C17H17NOo. By the action of H2SO4 on morphin at 100°, tAvo amorphous, basic products of condensation, trimorphin and tetramorphin, are pro duced. By heating together acetic anhydrid and morphin, three modi- fications, «, ft, }, of acetyl-morphin, .(CjHCqNOa, are formed. ALKALOID^ 445 Similarly substituted butyryl-, benzoyl-, succinyl-, camphoryl-, methyl-, and ethyl-morphin are also known. Although the synthesis of morphin has not yet been accom- plished, enough is known of its constitution to indicate that it contains the phenolic group (OH), and that it is a derivative of phenanthrene (see p. 423). The salts of morphin are crystalline. The acetate—Morphinee acetas, TJ. S.—Morphiee acetas, Br.—is a white, crystalline pow- der, soluble in 12 parts of water, which decomposes on exposure to air, with loss of acetic acid. The chlorid—Morphinee hydrc- chloras, TJ. S.—is less soluble, but more permanent than the ace- tate. The sulphate—Morphinee sulphas, TJ. S.—Morphiae sul- phas, Br.—is the form in which morphin is the most frequently used in medicine. It is a very light, crystalline, feathery powder; odorless, bitter, and neutral in reaction. It dissolves in 24 parts of water. Its solutions deposit morphin as a white precipitate on addition of an alkali. The crystals contain 5 Aq, which they lose at 130° (266° F.). Analytical Characters.—(1.) It is colored red, changing to yellow, by HN03. (2.) Cold concentrated H2S04 dissolves it, forming a colorless solution, which after 24 hours turns pink on addition of a trace of HN03; and the fluid when warmed, cooled, and diluted with H20, turns deep mahogany-brown on the addi- tion of a splinter of potassium dichromate. (3.) A mixture of morphin and cane-sugar (1 to 4) added to concentrated H3SO< gives a dark red color, which is intensified by a drop of bromin- water. (4.) If iodic acid solution and a drop of chloroform be added to morphin, free iodin is liberated, which colors the chlo- roform violet. If now dilute NH4HO be floated on the surface of the liquid, a dark brownish zone is formed. (5.) A neutral solu- tion of a morphin salt gives a blue color with neutral solution of ferric chlorid. (6.) A solution of molybdic acid in H2S04 (Frfihde’s reagent) gives with morphin a violet color, changing to blue, dirty green, and faint pink. Water discharges the color. (7.) Solution of morphin acetate produces a gray ppt. when warmed Avith ammoniacal sil\rer nitrate solution; and the filtrate turns red or pink with HN03. (8.) Auric chlorid gives a yelloAV ppt., turning \’iolet-blue, with solutions of morphin salts. (9.) Add solution of Fe2Cl6 (2-1G) to solution of potassium ferricyanid (the mixture must not assume a blue color), add morphin solution—a deep blue color. (10.) Heat morphin with concentrated H2S04 to 200° (392° F.) until green-black; add a drop of the liquid cau- tiously to water; the solution turns blue. Shake a portion with ether; the ether turns purple. Shake another portion with chlo- roform; the chloroform turns blue. (11.) Warm the solid alkaloid with concentrated H2SOi ; add cautiously a feAV drops of alcoholic 446 MANUAL OF CHEMISTRY. solution of KHO (30$); a yellow color is produced, changing to dirty red, then steel-blue, and sky-blue, and, with a further quan- tity of KHO solution, cherry-red. Codein—Codeina (U. S.)—C+H2]N03+Aq—299+18—crystallizes in large rhombic prisms, or from ether, without Aq, in octaliedra; bitter; soluble in 80 pts. cold water; 17 pts. boiling water; very soluble in alcohol, ether, chloroform, benzene; almost insoluble in petroleum-ether. Analytical Characters.—(1.) Cold concentrated H2SG4 forms with it a coloress solution, which turns blue after some days, or when warmed. (2.) Frbhde’s reagent dissolves it with a dirty green color, which after a time turns blue. (3.) Chlorin- water forms with it a colorless solution, which turns yellowish-red with NHiHO. Narcein—C23H2aNO.j+2Aq—463+36—crystallizes in bitter, pris- matic needles; sparingly soluble in water, alcohol, and amyl al- cohol ; insoluble in ether, benzene, and petroleum-ether. Analytical Characters.—(1.) Concentrated H2S04 dissolves it with a gray-brown color, which changes to red, slowly at ordi- nary temperatures, rapidly when heated. (2.) Frbhde’s reagent colors it dark olive-green, passing to red after a time, or when heated. (3.) Iodin solution colors it blue-violet, like starch. Narcotin—C22H23N07—413—crystallizes in transparent prisms, almost insoluble in water .and in petroleum-ether; soluble in al- cohol, ether, benzene, and chloroform. Its salts are mostly un- crystallizable, unstable, and readily soluble in water and alcohol. Analytical Characters.—(1.) Concentrated H2S04 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 H2S04, if grad- ually evaporated until the acid volatilizes, turns orange-red, bluish-violet and reddish-violet. (3.) Frbhde’s reagent dissolves it with a greenish color, passing to cherry-red. Thebain—Paramorphin—C+H+NCh—311—crystallizes in white plates; tasteless when pure; insoluble in water; soluble in al- cohol, ether and benzene. Analytical Characters.—(1.) With concentrated H2S04 an immediate bright red color, turning to yellowish-red. (2.) Its solu- tion in chlorin-water turns reddish-brown with NH4HO. (3.) With Frbhde’s reagent same as 1. Apomorphin—Ci7H17N02—is used hypodermically as an emetic in the shape of the clilorid, Apomorphinse hydrochloras, U. S. It is obtained by sealing morpliin with an excess of strong HC1 in a thick glass tube, and heating the whole to 140° (252° F.) for two to three hours. It is obtained also by the same process from codei'n. The free alkaloid is a white, amorphous solid, difficultly soluble in water. The chlorid forms colorless, shining crystals, ALKALOIDS. 447 which have a tendency to assume a green color on exposure to light and air. It is odorless, bitter and neutral; soluble in 0.8 parts of cold water. Toxicology of Opium and its Derivatives.—Opium, its prepara- tions and the alkaloids obtained from it, are all active poisons. They produce drowsiness, stupor, slow and stertorous respiration, contraction of the pupils, small and irregular pulse, coma, and death. The symptoms set in from 10 minutes to 3 hours, some- times immediately, sometimes only after 18 hours. Death has occurred in from 45 minutes to 3 days, usually in 5 to 18 hours. After 24 hours the prognosis is favorable. Death has been caused in an adult by one-half 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: Nar- cefn, morphin, codein; in tetanizing action: thebaln, papaverin, narcotin, codeTn, morphin; in toxic action: thebaln, codern, papa- verin, narcel’n, morphin, narcotin. 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 should be kept awake. After death the reactions for meconic acid and narcotin permit of distinguishing whether the poisoning was by opium or its preparations, or by morphin. Cinchona Alkaloids.—Although by no means so complex as opium, cinchona bark contains a great number of substances: quinin, cinchonin, quinidin, cinchonidin, aricin; quinic, quino- tannic, and quinovic acids ; cinchona red, etc. Of these the most important are quinin and cinchonin. Quinin—Quinina (XT. S.)—C,flH2,N.,0'2-(-n Aq—324+M18—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 alka- loid, 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 G parts per 1,000. Jt is known in three different states of hydration, with 1, 2, and 3 Aq, and anhydrous. The anhydrous form is an amorphous, resinous substance, obtained by evaporation of solutions in anhy- drous alcohol or ether. The first hydrate is obtained in crystals by exposing to air recently precipitated and well-washed quinin. 448 MANUAL OF CHEMISTRY. The second by precipitating by ammonia a solution of quinin sulphate, in which H has been previously liberated by the action of Zn upon HsS04; it is a greenish, resinous body, which loses H20 at 150° (302° F.). The third, that to which the following remarks apply, is formed by precipitating solution of quinin salts with ammonia. It crystallizes in hexagonal prisms; very bitter; fuses at 57 (134°.0 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 H20; very soluble in alcohol and chloro- form ; soluble in amyl alcohol, benzene, fatty and essential oils, and ether. Its alcoholic solution is powerfully laevogyrous, [aJD=—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 H2S04 dissolves quinin in colorless but fluorescent solution (see below). (2.) Solutions of quinin salts turn green when treated with Cl and then with NHa. (3.) Cl passed through II20 holding quinin in suspension forms a red solution. (4.) Solution of quinin treated with Cl water and then with fragments of potassium ferrocyanid be- comes pink, passing to red. Sulphate—Disulphate—Quininae sulphas (TJ. S.)—Quiniae sul- phas (Br.)—S0.,(C2„H25N202)2+7Aq—746+126—crystallizes in pris- matic 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; solu- ble in 740 pts. H20 at 13° (55°.4 F.), in 30 pts. boiling H20, and 60 pts. alcohol. Its solution with alcoholic solution of I deposits brilliant green crystals of iodoquinin sulphate. Hydrosulphate—Quininae bisulphas (TJ. S.)—S01H(C2l,H25N2 02)+7Aq—422+126—is formed when the sulphate is dissolved in excess of dilute H2S04. It crystallizes in long, silky needles, or in short, rectangular prisms; soluble in 10 pts. H20 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.—Quinin 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 H) of NH4HO; the liquids should separate into two clear layers, without any milky zone between them (cinchonin). (2.) Dissolved in hot H20, the solu- tion precipitated with an alkaline oxalate, the filtrate should not ppt. with NH-iHO (quinidin). (3.) It should dissolve completely in dilute H2S04 (fats, resins). (4.) It should dissolve completely in boiling, dilute alcohol (gum, starch, salts). (5.) It should not ALKALOIDS. 449 blacken with H2S04 (cane-sugar). (6.) It should not turn red or yellow with II2S04 (salicin and phlorizin). (7.) It should leave no residue when burnt on platinum foil (mineral substances). By the action of alkaline hydrates upon quinin, formic acid, chinolin (see p. 426), and pyridin bases (see p. 415) are produced. Concentrated HC1 at 140 -150° (284°-302D F.) decomposes quinin, with separation of methyl chlorid and formation of apoqriinin, C1S)H22N202, an amorphous base. Oxidizing agents produce from quinin oxalic acid and acids re- lated to pyridin, notably pyridindicarbonic or cinchomeronic acid, CoH,N(COOH)., which are also formed by oxidation of cinchonin. Although cinchonin (see below) differs from quinin in composi- tion by -f-O, and although the decompositions of the two bases show them both to be related to the chinolin and pyridin bases, attempts to convert cinchonin into quinin have resulted only in the formation of other products, among which is an isomere of quinin, oxycinchonin. Methylquinin, C20H2 ,N.O ,CH , is a base which has a curare-like action. Cinchonin—Cinchonina (TJ. S.)—CmHj .N.O—294—occurs in Pe- ruvian bark in from 2 to 30 pts. per 1,000. It crystallizes without Aq in colorless prisms; fuses at 150 (302° 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 cinchonin resemble those of quinin in composition; are quite soluble in 1I20 and alcohol; are not fluorescent; permanent in air; phosphorescent at 100c (212° F.). Q,uinidin and Quinicin—are bases isomeric with quinin; the former occurring in cinchona bark, and distinguishable from quinin by its strong dextrorotary power; the second a product of the action of heat on quinin, not existing in cinchona. Cinchonidin—a base, isomeric with cinchonin, occurring in cer- tain varieties of bark; laevogyrous. At 130° (266° F.) H2S04 con- verts it into another isomere, cinchonicin. Caffein—Them—Guaranin—Caffeina (XT. S.)—CBHi„N,02-|-Aq— 194-(-18—exists in coffee, tea, Paraguay tea, and other plants. It crystallizes in long, silky needles; faintly bitter; soluble in 75 pts. H20 at 15° (59° F.); less soluble in alcohol and ether. Hot fuming HN03 converts it into a yellow liquid, which after evap- oration turns purple with NH4HO. Alkaloids of the Loganiaceae.—Strychnin—Strychnina (U. S.) —C21H32N2O2—334—exists in the seeds and bark of different varie- ties of strychnos. It crystallizes on slow evaporation of its solutions in ortho- rhombic prisms, by rapid evaporation as a crystalline powder; 450 MANUAL OF CHEMISTRY. very sparingly soluble in H20 and in strong alcohol; soluble in 5 pts. chloroform. Its aqueous solution is intensely bitter, the taste being perceptible in a solution containing 1 pt. in 000,000. It is a powerful base; neutralizes and dissolves in concentrated H2S04 without coloration; and precipitates many metallic oxids from solutions of their salts. Its salts are mostly crvstallizable, soluble in 1I20 and alcohol, and intensely bitter. The acetate is the most soluble. The neutral sulphate crystallizes, with 7 Aq, in rectangular prisms. The iodids of methyl and ethyl react with strychnin to produce the iodids of methyl or ethylstrychnium, white, crystalline, basic substances, producing an action on the economy similar to that of curare. When acted on by H2S04 and potassium chlorate, with proper precautions, strychnic origasuric acid is formed. Analytical Characters.—(1.) Dissolves in concentrated H2SO4 without color. The solution deposits strychnin when di- luted 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 strychnin in H2S04, it is followed by a streak of color; at first blue (very transitory and frequently not observed), then a bril- liant violet, which slowly passes to rose-pink, and finally to yel- low. Reacts with grain of strychnin. (3.) A dilute solution of potassium dichromate forms a yellow, crystalline ppt. in strychnin solutions; which, when washed and treated with con- centrated H2S04, gives the play of colors indicated in 2. (4.) If a solution of strychnin be evaporated on a bit of platinum foil, the residue moistened with concentrated II2S04, the foil connected with the -f- 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.) Strychnin and its salts are intensely bitter. (6.) A solution of strychnin intro- duced under the skin of the back of a frog causes difficulty of respiration and tetanic spasms, which are aggravated by the slightest irritation, and twitching of the muscles during the in- tervals between the convulsions. With a small frog, whose sur- face has been dried before injection of the solution, grain of acetate of strychnin will produce tetanic spasms in 10 minutes. (7.) Solid strychnin, moistened with a solution of iodic acid in II2S04, produces a yellow color, changing to brick-red and then to violet-red. (8.) Moderately concentrated HN03 colors strychnin yellow in the cold. A pink or red color indicates the presence of brucin. Toxicology.—Strychnin is one of the most active and most frequently used of poisons. It produces a sense of suffocation, thirst, tetanic spasms, usually opisthotonos, sometimes empros- ALKALOIDS. 451 thotonos, 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 from 5 minutes to 6 hours, usually within 2 hours. Death has been caused by £ grain, and recovery has followed 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. Strychnin 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. Brucin—CL, H.6N -0,+4 Aq—394+72—accompanies strychnin. 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 strychnin, but much less energetic. Axalytical Characters.—(1.) Concentrated HXOa colors it bright red, soon passing to yellow; stannous chlorid, or colorless NH iHS, changes the red color to violet. (2.) Chlorin-water,or Cl, colors brucin bright red, changed to yellowish-brown by NH4HO. Alkaloids of the Solanacese.—Solanin—C43H71NOj«—857—ob- tained from many species of Solarium; crystallizes in small, white, bitter, sparingly soluble prisms. Concentrated H2S04 colors it orange-red, passing to violet and then to brown. It is colored yellow by concentrated HC1. It dissolves in concen- trated ,HNOs, the solution being at first colorless, but after a time becomes purple. Atropin—Daturin—Atropina, TJ. S.—Atropia, Br.—CuH23N03— 289—occurs in Air op a belladonna and in Datura stramonium. It forms colorless, silky needles, which are sparingly soluble in cold water, more readily soluble in hot water, very soluble in chloro- form. It is odorless, but has a disagreeable, persistent, bitter taste. It is distinctly alkaline, and neutralizes acids with forma- tion of salts. One of these, the sulphate—Atropinee sulphas, U. S.—is a white, crystalline powder, readily soluble in water, which is the form in which atropin is usually administered. 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. 452 MANUAL OF CHEMISTRY. Characters.—(1.) If a fragment of potassium dichromate be dissolved in a few drops of H2S04, the mixture warmed, a fragment of atropin and a drop or two of H20 added, and the mixture stirred, an odor of orange-blossoms is developed. (2.) A solution of atropin dropped upon the eye of a cat produces dilatation of the pupil. (3.) The dry alkaloid (or salt) is moist- ened with fuming HNO3 and the mixture dried on the water- bath. When cold it is moistened with an alcoholic solution of KHO—a violet color which changes to red. When atropin is heated with concentrated HC1 to 120°-130° (248°-2GG° F.) for several hours, or when it is warmed with baryta- water to 58° (136°.4 F.) it is decomposed into a base related to the pyridins: Tropin—C;HU—OH,NCH3—and, at first, tropic acid— C.»Hio03—but, later, atropic acid—CH2—C(CcH5)COOH. Tropin is also producd by a similar decomposition of hyoscyamin. Hyoscyamin—Ci5H23N03—occurs, along with another base, hy- oscin, isomeric with atropin, in Hyoscyamus niger. It crystallizes, when pure, in odorless, white, silky needles whose taste is very sharp and disagreeable, and which are very sparingly soluble in water. As most commonly met with, it forms a yellowish, soft, hygroscopic mass which gives off a peculiar, tobacco-like odor. It neutralizes acids. Its sulphate— Hyoscyaminee sulphas, U. S. —forms yellowish crystals, very soluble in water, hygroscopic, and neutral in reaction. Alkaloids from other Sources.—Ergotin—C5oHS2N2Os—and Ec- bolin are two brown, amorphous, faintly bitter, and alkaline alkaloids obtained from ergot. They are readily soluble in water and form amorphous salts. The medicinal preparations known as ergotin are not the pure alkaloid. Colchicin—Ci7H19N06—occurs in all portions of Colchicum an- tumnale and other members of the same genus. It is a yellowish- white, gummy, amorphous substance, having a faintly aromatic odor and a persistently bitter taste. It is slowly but completely soluble in water, forming faintly acid solutions. It forms salts which are, however, very unstable. Concentrated HN03, or, preferably, a mixture of II2S04, and NaN03 colors colchicin blue-violet. If the solution be then di- luted with H20, it becomes yellow, and on addition of NaHO solution, brick-red. Veratrin—Veratrina, IT. S.—C32H;,2N209—occurs in Veratrum of- ficinalis—Asagraa officinalis, accompanied by Sabadillin—C10H2« NjOff—Jervin—C30H46N2O3—and other alkaloids. The substance to which the name Veratrina, TJ. S., applies is not the pure alka- loid, but a mixture of those occurring in the plant. Concentrated H2S04 dissolves veratrin, forming a yellow solu- 453 ALKALOIDS. tion turning orange in a few moments, and then, in about half an hour, bright carmine-red. Concentrated HC1 forms a colorless solu- tion with veratrin, which turns dark red when cautiously heated. Piperin—CitH1uN03—occurs in black and white pepper. It crys- tallizes in colorless, transparent prisms; almost tasteless when pure; very sparingly soluble in water. It is a very weak ba'se. If piperin be heated with alcoholic KHO, it is decomposed into piperidin—C5HnN—and piper ic acid—CnHioCh. If piperidin be treated with silver oxid, pyridin (see p. 416) is formed. Berberin—Xanthopicrite—CjuHnNO,—occurs in Berberis vul- garis, Cocculus palmatus, and many other plants. It crystallizes in fine yellow needles or prisms; bitter in taste and neutral in reaction. It is difficultly soluble in cold water, readily soluble in alcohol and in boiling water. It forms well-defined, crystalline, yellow salts. Aconitin—Co6H35N07(0H):,0(C0,C,.,H5)—is an alkaloid obtained from Aconitum napellus and other species of aconitum. It is a colorless and odorless powder, possessed of an intensely bitter taste, and sharp, burning after-taste. It is strongly alkaline; almost insoluble in water, readily soluble in alcohol, ether, chloro- form, or benzene. It neutralizes acids completely, with formation of well-defined, crystalline salts. Aconite contains, besides aconitin, three other alkaloids, if not a greater number: Napellin, acolyctin, and lycoctonin. These three alkaloids, notably the first named, along with small quan tities of aconitin, constitute the English or Morson’s “aconitin,” which is probably made from Aconitum ferox. Probably, also, all commercial samples of aconitin are mixtures of aconitin and napellin with lesser quantities of the other alkaloids and acorin and pseudaconin. If aconitin be heated in sealed tubes with HaO to 140’-150° (284°-302° F.) for several hours, it is decomposed into benzoic acid and aconin, C26H:]SNO;(OH)4. A Japanese variety of aconite contains a peculiar alkaloid: Japaconitin, CfieH^NjOj. Analytical Characters.—(1.) Concentrated HaS04 dissolves aconitin, forming a light, yellow-brown solution, which slowly turns darker, and changes to light yellow on addition of HN03. (2.) If aconitin be dissolved in aqueous phosphoric acid, and the solution very gradually evaporated, a violet color is produced. Toxicology.—Aconite and aconitin have been the agents used in quite a number of homicidal poisonings. The symptoms usually manifest themselves within a few min- utes ; sometimes are delayed for an hour. There is numbness and tingling, first of the mouth and fauces, later becoming general. There is a sense of dryness and of constriction in the throat. Per- 454 MANUAL OP CHEMISTKY. sistent vomiting usually occurs, but is absent iii some cases. There is diminished sensibility, with numbness, great muscular feebleness, giddiness, loss of speech, irregularity and failure of the heart’s action. Death may result from shock if a large dose of the alkaloid be taken, but more usually it. is by syncope. Tlie treatment should be directed to the removal of unabsorbed poison by the stomach-pump, and washing out of the stomach with infusion of tea holding powdered charcoal in suspension. Stimulants should be freely administered. Pilocarpin—CiiHi6N ,02—is the principal alkaloid of jaborandi. It forms a colorless, amorphous mass, readily soluble in water, alcohol, ether, and chloroform. It readily forms salts. Its chlo- rid—Pilocarpinae hydrochloras, U. S.—occurs in white, deliques- cent, odorless crystals. Cocain—Ci7Hai04—is an alkaloid obtained from the leaves of Erythroxylon coca. It crystallizes in large, six-sided prisms. Its taste is at first bitter, producing paralysis of the sense of taste subsequently. It is strongly alkaline. Its chlorid, extensively used for the production of local anaesthesia, crystallizes in well- formed prismatic needles, readily soluble in water. When heated with concentrated HC1, it is decomposd into ben- zoic acid, methyl alcohol, and a new base, eegonin, CsHlsN03. Physostigmin—Eserin——is an alkaloid existing in the Calabar bean, Physostigma venenosum. It is a colorless, amorphous solid, odorless and tasteless, alkaline and difficultly soluble in water. It neutralizes acids completely, with formation of tasteless salts. Its salicylate—Physostigminse salicylas, TJ. S. —forms short, colorless, prismatic crystals, sparingly soluble in water. Concentrated H2S04 forms a yellow solution with physostigmin or its salts, which soon Dims olive-green. Concentrated HN03 forms with it a yellow solution. If a solution of the alkaloid in H2SO4 be neutralized with NH4HO, and the mixture warmed, it is gradually colored red, reddish-yellow, green, and blue. Curarin—C36H36N (?)—is an alkaloid obtainable from the South American arrow-poison, curare, or woorara. It crystallizes in four-sided, colorless prisms, which are hygroscopic, faintly alka- line, and intensely bitter. Curarin dissolves in II2S04, forming a pale violet solution, which slowly changes to red. If a crystal of potassium dichromate be drawn through the H2S04 solution, it is followed by a violet color- ation, which differs from the similar color obtained with strychnin under similar circumstances, in being more permanent, and in the absence of the following pink and yellow tints. Emetin—Ch-H.,0Tr2OB—an alkaloid existing in ipecacuanha which crystallizes in colorless needles or tabular crystals, slightly bitter and acrid; odorless, and sparingly soluble in water. ALKALOIDS. It dissolves in concentrated H2S04, forming a green solution, which gradually changes to yellow. With Frdhde’s reagent it gives a red color, which soon changes to yellowish-green and then to green. Ptomains.—This name, derived from Tirana=that which is fallen —i.e., a corpse—was first suggested by Selmi to apply to a class of substances, first distinctly recognized by him, which are produced from albuminoid substances under the influence of putrefactive decomposition, and which are distinctly alkaloidal in character. The ptomains are possessed of all of the distinguishing charac- ters of the vegetable alkaloids. They are alkaline in reaction, and combine with acids to form salts. Some are liquid, others are solid and crystalline. Some are actively poisonous, others are practically inert. They behave toward the general reagents for alkaloids in much the same way as do the vegetable alkaloids. Although the names ptomains and cadaveric alkaloids are ap- plied to alkaloids of animal origin, it is certain that such alkaloids may be and are produced during life in the animal economy. It was feared that, as alkaloidal substances in many respects resembling those of vegetable origin are produced in the animal body, not only after death, but during life, grave doubts would be cast upon the results of analyses made to detect the presence of poisonous vegetable alkaloids in the cadaver in cases of sus- pected poisoning. Such fears were by no means groundless, as there is abundant evidence that ptomains have been mistaken for vegetable alkaloids in chemico-legal analyses. The ptomains, however, as well as the vegetable alkaloids, may be positively identified by a careful analysis, based upon the use, not of a single reaction, but of all known reactions for the alkaloid in question. Therefore, it is possible to positively predicate the existence or non-existence of a given vegetable alkaloid in a cadaver, but it can only be done after a thorough and conscientious examination by all physiological and chemical reactions. The ptomains have of recent years assumed great importance to the physician by reason of their bearing upon the etiology of disease, and sufficient experimental evidence has already been obtained to warrant the belief that the method of action of many of the known pathogenic bacteria is by their production of alka- loidal poisons (see below). One of the first of the putrid alkaloids to be formed in cadaveric matter is cholin (see pp. 27G, 361), which undoubtedly has its ori- gin in the decomposition of the lecithins. Neuridin—Cr,H14N3 (?)—is a diamin, related to neurin (see p. 277), which is formed during the early stages of cadaveric putre- faction. It is gelatinous, readily soluble in water, insoluble in MANUAL OF CHEMISTRY. alcohol and ether, and very prone to decomposition, yielding dimethylamin and trimethylamin. It forms a chlorid which crystallizes in long, transparent needles, very soluble in water. It is non-poisonous. Cadaverin — C5H14N2 — identical with pentamethylendiamin, Nib—(CH 2)0—NH2, is formed at a somewhat later stage of cadav- eric putrefaction, along with putrescin and saprin (see below). Its chlorid is crystalline, hygroscopic, very soluble in water, in- soluble in strong alcohol and ether. Like most of the ptomains and several of the vegetable alkaloids, it gives a distinct blue color with ferric chlorid and potassium ferricyanid. It is non-poisonous. Putrescin—CiH12N.>—and Caprin—CsHi8Na—are two non-poi- sonous diamins produced along with cadaverin. They are both liquid, and each forms a crystalline chlorid. Mydalein is a putrid alkaloid, of undetermined composition, forming a difficultly crystallizable, hygroscopic chlorid, which is actively poisonous. Five milligrammes administered hypoder- mically to a cat causes death after profuse diarrhoea and secretion of saliva, violent convulsions, and paralysis, beginning with the extremities and extending to the muscles of respiration. Neurin (see p. 277) is produced during the later stages of putre- faction. It is actively poisonous, and produces symptoms similar to those caused by muscarin. Atropin is a powerful antidote to its action. Mydin—C„HnNO —is a base produced after continued putrefac- tion at comparatively low temperatures. It is a powerful base and a strong reducing agent, and has an ammoniacal odor. It is non-poisonous. Mydatoxin—CfHi2N02—is a strongly alkaline syrup, which pro duces, when administered to animals, violent clonic spasms, fol- lowed by paralysis and death. Other ptomains produced during putrefaction of meat, fish, etc., are methylguanidin, C,H7N:,—poisonous; muscarin, C:,Hi;NO;,— poisonous; and gadinin, C7Hi7N02—non-poisonous. An alkaloid, many of whose chemical reactions have been de- termined, although its composition is unknown, has been obtained from the internal organs, and dejecta of cholera victims, as well as from cultures of the comma bacillus. This alkaloid, when ad- ministered to animals, causes symptoms of poisoning and death. From the cultures of the Koch-Eberth typhus bacillus an alka- loid has been isolated—Typhotoxin, C;Hi;NOj—which, when ad- ministered to animals, causes paralysis, copious diarrhoea, and death. Tetanin—Ci;.HaoN.-04—is an alkaloid obtained from cultures of a bacillus originating from a wound which had been the cause of death by tetanus. It forms a deliquescent chlorid, and a very ALKALOIDS. soluble chloroplatinate. The free base or its chlorid, when in- jected into mice or guinea-pigs, causes clonic or tonic convulsions of the greatest intensity, which terminate in death. Mytilitoxin—CfiH15NOo—is an alkaloid obtained from poisonous mussels, which, when administered to animals in small amount, causes the same symptoms as are produced by the mussels. 458 MANUAL OF CHEMISTRY. ALBUMINOIDS AND GELATINOIDS. Protein Bodies. The substances of this class are never absent in living vegetable or animal cells, to whose “life” they are indispensable. They are as yet the products exclusively of the organized world. Physical Characters.—They are almost all uncrystallizable and incapable of dialysis. Some are soluble in water, others only in water containing traces of other substances, others are insoluble. Their solutions are all laevogyrous. 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 different albumi- noids, and is of value in distinguishing them from one another. Composition.—They consist of C, N, H, O, and usually a small quantity of S, and form highly complex molecules, whose exact composition is uncertain. Of their constitution nothing is defi- nitely known, although there is probability that they are highly complex ainids, related to the ureids, and formed by the com- bination of glycollamin, leucin, tyrosin, 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.) with Mil Ion’s reagent. The reagent is made by dissolving, by the aid of heat, 1 pt. Hg in 2 pts. HN03 of sp. gr. 1.42, diluting with 2 vols. H30, and decanting after 24 hours. (2.) A yellow color with HN03; changing to orange with NH4HO (xanthoproteic reaction). (8.) A purple color with Pettenkofer’s test (q.v.). (4.) With a drop or two of cupric sulphate solution and liquor potass* a vio- let color. (5.) A solution of an albuminoid in excess of glacial acetic acid is colored violet and rendered faintly fluorescent by concentrated H2S04. (6.) With potassium ferrocyanid, in solu- tions strongly acid with acetic acid, a white ppt. > Decompositions.—Dilute acids decompose them into two sub- stances: one insoluble, amorphous, yellowish, called hemipro- tein; the other soluble in water, insoluble in alcohol, faintly acid, called hemialbumin. A prolonged boiling with moderately con- centrated H2S04 decomposes them, forming well-defined sub- stances—glycocol, leucin, tyrosin; aspartic and glutamic acids. Alkalies dissolve them more or less readily; on boiling the solu- tion, part of the sulphur is converted into sulphid and hyposul- phite. Their alkaline solutions, when neutralized by acids, de- ALBUMINOIDS AND GELATINOIDS. 459 posit Mulder’s protein. Concentrated alkalies decompose them into amido-aeids: By fusion with alkalies, alkaline cyanids are also produced. When they are heated with caustic baryta and water at 100D (212° F.), carbonate, sulphate, oxalate, and phosphate of barium are deposited, and C02 and 2s Ha are given off in the same proportions as when urea is similarly treated; when the temperature is raised, under pressure, finally to 2003 (392° F.), a crystalline mass is formed which Contains oxalic and acetic acids, a number of amido-acids, aspartic and glutamic acids, and a sub- stance resembling dextrin. Heated with HaO, under pressure, they are partly dissolved and partly decomposed. A mixture of HaSCh and manganese dioxid, or potassium dichromate, produces aldehydes, and acids of the fatty and benzoic series, hydrocyanic acid, and cyanids from the albuminoids. When heated under pressure with Br and H20 they yield COa, oxalic and aspartic acids, amido-acids, and bromin derivatives of the fatty and ben- zoic series. Potassium permanganate produces from them urea, COa, ATHa and H20. Putrefaction is a decomposition of dead albuminoid and gelati- nous matter, 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 surface if it be liquid. The prod- ucts of putrefaction vary with the conditions under which it occurs. The most prominent are: N, H, hydrocarbons, H2S, 2f H3, C02, 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 un- determined nitrogenous substance. Putrttfaction may be prevented by: (1) exclusion of air; (2) re- moval of water; (3) maintaining the temperature below 5° (41° F.); (4) the action of antiseptics. Antiseptics are substances which prevent or restrain putrefac- tion. Deodorizers, or air purifiers, are substances which destroy the odorous products of putrefaction. Disinfectants are substances which restrain infectious diseases by destroying their specific poisons. Certain substances are antiseptic, deodorant, and disinfectant; MANUAL OF CHEMISTRY. such are: chlorin, bromin, iodin, the hypochlorites, and sulphur dioxid; others lack one of the powers, as the mineral acids and the non-volatile “disinfectants,” which are antiseptic and disin- fectant, 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 erema- causis, differing from putrefaction in that the substances decom- posed are the carbohydrate instead of the azotized constituents, and in the products of the decomposition, 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 knowl- edge of the chemical constitution of these substances, we can only adopt a temporary classification, based upon their physical and physiological characters. A. Albuminoids: I. Soluble in pure water ; coagulated by heat.—The true albu- mins of the white of egg, serum, and vegetable albumin. II. Insoluble in pure water; soluble in water without altera- tion in presence of neutral salts, alk alies and acids ; and capable of precipitation unch anged fi om these solutions. 1. Globulins.—Vitellin, 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 cryptolytes.—Albuminates (so called), acid albumin, syntonin, hemiprotein, 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. IV. Coagulated.—Coagulated albumin and fibrin. V. Amyloid matter.—Lardacein. 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 delicate membranes, in the white of egg. It is obtained in an impure condition by cutting the whites of eggs with scissors, ex- pressing through linen, diluting with an equal volume of water, filtering, and concentrating the filtrate at a temperature below ALBUMINOIDS AND GELATINOIDS. 461 40° (104° F.); mineral salts, which adhere to it tenaciously, are separated by dialysis. It is a mixture of two kinds of proteids. (1.) Those coagulable by heat. Of these, two are globulins (ra'nogen di'cya'nogen pa'racya'nogen glycogen aml'dogen *chlo'rIn *brd'mln *I'odIn *flu'or!n NON-METALS, ETC. sulphur phosphorus carbon boron silicon fars&'nicum METALS. Usage has determined the pronunciation except in a few in- stances. antimony bi smuth (biz-) cO'balt copper i'ron ma nganese (ez as in breeze) mercury nickel ku'pferni'ckel (koop) silver tii'ngsten zinc Words in -ium have antepenultimate accent, and the vowel of this syllable is short if i or y, or if before two consonants, but long otherwise. (Bolton & Howe ; aluml'n- ium) ammonium diS"thylammo'nium ba rium (Bolton: ba r- ium) beryllium cadmium Iridium ll'thium magne'sium (zhiuin) nlo'bium Osmium palladium phosphO'nium diS"thylpliosph6'nium potassium strO’ntium (shium) tellurium terbium thallium thorium ftlta'nium uranium vanadium ytterbium Fate, fat, far, mete, mSt, pine, pin, marine, n5te, nOt, move, tube, tttb, riile, my, y = I. ' Primary accent; " secondary accent. N. B.—The accent fol- lows the vowel of the syllable upon which the stress falls, but does not indicate the division of the word into syllables. ORTHOGRAPHY AND PRONUNCIATION. 495 cae'sium calcium cerium chrS'mium fdldy'mium erbium Indium rhd’dium ruthenium samarium scandium sSle ilium sodium yttrium zirconium lanthanum tmbiy'bdenum platinum tantalum TERMINATIONS IN -IC. Accent penultimate. Penultimate vowel in polysyllabic words short, except (1) u when not before two consonants ; and (2) when penultimate syl- lable ends in a vowel; in dissyllables long, except before two consonants. aluml'nic ammft'nic argg'ntic baric bismu'thic coba'ltic (a as in ball) manganic mercuric 16'dic mS'tantimb'nic mS'taphosphb’ric mS'tasta'nnic mbiy'bdic phosphb'ric py "rophosphb'ric sSIS'nic silicic su lphocya'nic tellu ric abifi'tic face’tic or acS'tic abietl'nic abs Inthic ac6ric acetb nic fnl'ckelic (ni'ck’lic) platl'nic pltt'mbic strb’ntic titanic unVnic ars& nic benzoic butyric cacodyiic camplibric carba'mic carbb'lic carbb'nic fchlS' racetic orchlo"- rac6'tic chrysopha'nic cinnamic citric cyanuric dialu'ric fuma'ric glycb’lic hippuric bora'cic boric bromic carbb'nic dlthib'nic ffi'rrocya'nic hydrld'dic hy'drochlo'ric phtha'lic (ta'lic) picric prussic fracS'inic or race mic rosS'llic saccharic salicylic seba'cic subg'ric tartaric fvalS'ric or vale'ric succl'nic alg'mbic allotrb'pic aromatic atb'mic Fate, fat, far, mete, m6t, pine, pin, marine, note, nbt, move, tube, tub, rule, my, f = I. ' Primary accent; " secondary accent. N. B.—The accent fol- lows the vowel of the syllable upon which the stress falls, but does not indicate the division of the word into syllables. 496 MANUAL OF CHEMISTRY. acety'lic aconl'tic aery'lie adl pic alcolib'lic aliza'ric allyiic amygdaiic amyiic hypogae'ic I'sobuty'ric malic malb'nic melll'tic methylic mu'cic myrb'nic oleic basic el8 "ctroiy tic IsomS'ric m5"noba'sic mo’nohydric polymeric tfitratd'mic triba'sic TERMINATIONS IN -OUS. Words in -ous, following the general rule of the language, take antepenultimate accent, except when two consonants follow the penultimate vowel, in which case the accent is thrown forward. (A clear distinction is thus made in accent as well as in termi- nation between words in -ic and -ous.) face'tous (exception through usage) arse'nious chlorous hy'drosu'lphurous hy'pochlorous hy'ponl'trous liy'pophb'sphbrous liy'posiilphurous phb'sphbrous sele'nious sulphurous tfi'llurous blsmuthous chro'inous cS'baltous manganous mercurous ni'ckelous pia'tinous tl'tanous alliaceous alumenl'ferous amyia'ceous auriferous ga seous (gazeous) gelatinous pyroligneous TERMINATIONS IN -ATE. Antepenultimate accent (occasionally thrown back). a'bietate a cerate acetate a'cetonate adipate a'lcoholate all' zarate ammo'niate amy'gdalate a’mylate antimo'niate arsenate cyanate fulminate gly'collate vanadate filtrate Accent analogous to -ate terminations. TERMINATIONS IN -ITK a’cetite a'ntimonite a rsenite h y" pophb'sphite m&'nnite Fate, fat, far, mete, met, pine, pin, marine, note, n5t, move, tfibe, ttfb, riile, my, f = I. 'Primary accent; "secondary accent. N. B.—The accent fol- lows the vowel of the syllable upon which the stress falls, but does not indicate the division of the word into syllables. ORTHOGRAPHY AND PRONUNCIATION. 497 * Drop final e in every case, and pronounce -Id (see Note 1). An- tepenultimate accent. TERMINATIONS IN -IDE AND -ID A cetA nilld hy'drld anhy drld A'nilld brS'mld chld'rld flu'orld iodld cy'Anld cyA melld glu'cosld hy drostilphld 6'xld hydrd'xld murg'xld b"xyclil5'rld Amid A'cetA'mtd A lkalA’mld bA'nzylA'mld cA'rbA'mld cyA'nA'mld di'A'cetA'mld dicyA'nA''mId lA'ctA'inld 6'xA "mid Hydrocarbons belonging to the -ane, -ewe, and -ine groups of Hofmann take long vowel. TERMINATIONS IN -ANE. mS'thane 6'thane h<3 xane hS’ptane 6'ctane i'sobu'tane I'sopS'ntane TERMINATIONS IN -ENE. Antepenultimate accent. Some dissyllables, as benzene, have no distinct accent. A'cenA’phthene A'cetnA’phthylene Asphaltene A'zobS'nzene bgnzene b6 nzylene butylene. capry'lidene cetene crotS'nylene decS'nylene dIA'mylene Acetylene A'llylene dlbrombfinzene 6'thidene 8'thylene hS'ptylene I'sobu'tylene i'sohfi'ptylene inesl'tylene mS'taxy'lene methylene naphthalene A'mylene t&'nthracene oenanthy'lidene pS'ntylene phenA'ntlirene terabfi'nthene tbluene valS'rylene xylene glu'tgn *albu’men TERMINATIONS IN -INE. Doubly unsaturated compounds in -ine take the normal pro- nunciation -ine. S'thine prb'pine Fate, fAt, far, mete, niAt, pine, pin, marine, note, nSt, move, tube, tub, rule, my, f = i. ' Primary accent ; " secondary accent. N. B.—The accent fol- lows the vowel of the syllable upon which the stress falls, but does not indicate the division of the word into svllables. 498 MANUAL OF CHEMISTRY. TERMINATIONS IN -IN. * All chemical compounds now ending in -in and -ine (except doubly unsaturated compounds, considered above) should end in -in, and this syllable should be pronounced -in (see Note 2). The accent is antepenultimate, except when the penultimate vowel is followed by two consonants, in which case the accent is penultimate. chlo'rln brd'mln l'ddln flp'drln ft'mln mS'thyl&'mln 6'thylft'mln &"cedi&'mln ft'cetonfi/mln phd'sphln a’rsln it'coni n acd'nitln fi/mmelln a'nthrapu'rpurln fi/sbolln ft'nilln asp&'ragln dichlorhy'drln diS'thylln diste'arln emu'lsln fibrin fluorfi'scln gS'latln gld'bulln gli'adln glu'tln gly'cerln (gly'cerdl preferred) fhS'mogld'bln bfi'nzln brii'cln cho'lln chry'soidln (oi as in soil) cinchd'nicln cl'nchonln cb'nln cmX'tinln cre'atln cu'rarln gua'nidln (gwa) gua'nln (gwa) hy'drazln hyoscy'amln mo'rphln 5'lSfIn qul'nicln my'osln na'rcotln neu'rln nl'cotln pAlmitln piXpAverln pfi’psln plp&ridln purpurln resorcin s&'licln sa'rcln ste'arln qul'nidln qul'nln ros&'nilln stry'chnln tolu'idln v&'selln Abifitln absi'nthln Acetln alizarin alloxantin Allylln amy'gdalln ft'mylln au'rln coni'ferln cu'marln dS'xtrln *the'In (teln) (Hart: word should be drbpped) fhg'matln flndigotln I'nulln I' satin leu'cln mo''noste'arIn {X'tropln sy’ntonln t&'nnln *v&'nlllln Fate, f&t, far, mete, mSt, pine, pin, marine, note, n5t, move, tube, tub, rule, my, y = I. ' Primary accent; " secondary accent. N. B.—The accent fol- lows the vowel of the syllable upon which the stress falls, but does not indicate the division of the word into syllables. ORTHOGRAPHY AND PRONUNCIATION. 499 (In following nine words, penultimate accent ob- scure.) the'bain fco'caln acrolein cA'ffeln co'defn casein fluorescein na'rceln coniln allAntSIn fb6nzoIn Alkaline cry' stall! n or crystal- line. TERMINATIONS IN -ONE AND -ON *albu'mInone A nthraqulnone qulnone ketone Acetone bo'rbn carbon hydrocarbon collo'dibn silicon TERMINATIONS IN -AR, -ID, -OL, -YL, -YDE, ETC. A'cetAl bA'nzAl chlo'rAl ni'trll A'cetoni'trll -oZ, final e dropped ; 61, with two exceptions from usage. A'lcohbl A'nfithol argbl be’nzdl (undesirable; should be dropped) crfi'sol giy'cerdl tgiy'coi I'ndol fnA'phthol *phS'nol * thy mol (tl) -yl, antepenultimate accent. AcC'tonyl fAcetyi Allyl fcarbb'Xyl ce'rotyl ce'tyl chroinyi dlA'llyl dIA'myl dimethyl Amyl bl'smuthyl b6 "rethyl dlphfi'nyl dipro’pyl formyl hg'ptyi fhydrb’xyi l'sobu'tyl I"sopr5'pyl butyl cA'codyl carbonyl lA'ctyi mS'thyl fnltrd'xyl nl'tryl 6'ctyi fphe'nyi prS'penyl fA'ldehyde Acetaldehyde -yde, antepenultimate accent. be "nz.A'Idehyde mg’ta'ldehyde pa "rAldehyde Fate, fAt, far, mete, m£t, pine, pfu, marine, note, nbt. move, tube, tub, rule, iny, f = I. ' Primary accent; " secondary accent. N. B.—The accent fol- lows the vowel of the syllable upon which the stress falls, but does not indicate the division of the word into syllables. 500 MANUAL OF CHEMISTRY. -METER. fWords ending in the termination -meter take the normal an- tepenultimate accent (from usage) ; except that the words of this class used in the metric system are considered as compouud words, and each portion retains its own accent. acetl'meter acetoineter acldl'ineter alcoholometer alkall'meter barO'meter eudiO'meter brdinoform chloroform lO'doform a'mylose c0'llul5se dextrose glucose lactose fl6'vulose maltose (a as in ball) su’crOse sy'naptose micro meter (instru- ment) ureO'meter urindlneter mlllime''ter c6'ntime"ter MISCELLANEOUS. acetl'metry acidl'metry alcoholO'metry alkalimetry [in boil) fstoichiOTnetry (oi as alcoliolomg'tric barometric acetifica'tion cupella'tion distillation ebullition fermentation lixivia'tion ftltra'tion valence qua'ntiva'lence md'nova lent fgrain(so derivatives) filter f titer (to be avoided) ftltrate ftltra'tion ammonia ammoniac dS'kame'ter de'cime'ter h8'ctome"ter kI'lome''ter my'riame"ter mi'-crome"ter (meas- ure) bl'va'lent tri'va'lent fqua'driva'lent quinquivalent atomicity basl'city monad tetrad f ailotrOpy fa'llotrOpism fi'somerism fpO'lymerism analysis atmO'lysis dialysis electrolysis acetify fbary'ta bo'rax caramel ll'tharge •f oie flant saltpeter verdigris alkaloid amyloid cO'lloid crystalloid *albu'minoid oi as in boil acl dify aerate aeriform falloy' (noun) falloy' (verb) amalgam ama'lgama'tor Fate, fAt, far, mete, met, pine, pin, marine, note, n5t, move, tube, tub, riile, my, y = I. ' Primary accent; " secondary accent. N. B.—The accent fol- lows the vowel of the syllable upon which the stress falls, but does not indicate the division of the word into syllables. ORTHOGRAPHY AND PRONUNCIATION. 501 *appara tus (plural) fa ssay (noun) (•assay' (verb) (assay'er *c6'ncentrated dft flagrating dilute *mo’lecule *m6l6'cular fe rment (noun) ferment nascent ■f me ter ammoni'ftcftl *ft'ntimonetted *a rsenetted ca rbutted te'lluretted sii lpliuretted phO'sphoretted ft'dipocere Alkali ft'lkanet fallO'xan ft ntichlor •(asbestos ft sphftlt ftclcular Alchemist ft'node ftqua fo'rtis ftqua re gia (re-gi-a) centigrade crystallography fu'marole gftngue me'tallu "rgy *n5'mSncla ture 6peiss (spice) tu'bulature Fate, flit, far, mete, mftt, pine, pin, marine, note, n6t, move tube, tub, rule, my, y = i. ' Primary accent; " secondary accent. N. B.—The accent fol- lows the vowel of the syllable upon which the stress falls, but does not indicate the division -of the word into syllables. Note 1. Ad.—'This pronunciation distinguishes clearly between Ad and Ate. In German it is difficult and often impossible to dis- tinguish between -id and -it, and in English a confusion often arises between chlorite and chloride, sulphite and sulphide, etc. See also the following note. Note 2. An.—The final e in these words should be dropped as of no important significance. I. The suggestion of Watts and others to indicate basic sub- stances by -ine and all others (or neutral substances) by -in seems unwise. It makes a difference in spelling, with little or no cor- responding difference in pronunciation on the part of most chem- ists—a useless and undesirable complication. It demands a very extensive knowledge of the constitution of a great number of compounds with these terminations. It has been partially adopted by many chemists but not consistently by most, and by many it has never been recognized. II. All continental languages use the pronunciation An, and this is the case with not a few words in English, as benzine, marine, while the American public have instinctively taken up this pronunciation in “Pearlfne, Soapine,” etc. In general, how- ever, it seems too foreign to English usage to be adopted by a majority of American chemists. -ine is awkward and would be very foreign to English usage in many words, as chlorine, morphine, nicotine, brucine, etc., etc. The pronunciation An is already common in many of these words, as the halogens, anilln, hematin, pepsin, tannin, etc., and at the same time presents a near approach to the continental in, into which it may easily be strengthened if preferred. The above note applies equally to the termination Ad. APPENDIX B.-TABLES. TABLE I.—SOLUBILITIES. Fresenitjs. W or w = soluble in H20. A or a = insoluble in H20 ; soluble in HC1, HNOs, or aqua regia. I or i = insolublein H20 and acids. W-A = sparingly soluble in H20, but soluble in acids. W-I = sparingly soluble in HaO and acids. A-I = insoluble in H20, sparingly soluble in acids. Capitals indicate common substances. a a p g s' a "c o a P O a a p 5 p g a a p P a m CQ O E 4-> CQ 3 3 CQ 3 CQ i Zinc 1 Acetate W w w w-a w w w w w W W W w Arsenate a a a a a a w a w a a a Arsenite a a a a a a W a W a a w w w-a W Borate a w-a a a w a w a a a Bromid w-i w w a-i w w w a w w w Carbonate A A A a a A w a w A A w w W w w w w w W w w w W-I w w A-I W" w W2» i w W w w w Chromate A-I w W a w-a a w a W w-a a w a w a a w-a w w a w a w-a Cyanid a w a w a-i w i W w a Ferricyanid.... w-a w i i w i W a Ferrocyanid ... a w a i w i w w a-i Fluorid a a-i a w-a w-a w w w a-i w W w-a w-a w w w w w W w w w w w a A a a w w w a a a Iodid W-A w w A A w w i w w w W w w-a w w a w-a w w-a w w w w w w w w w w w w w w w w a a w-a a a a w a w a a w a Oxid A A A15 A A A w a w w a A-I A Phosphate. ... a a3 a a a a W a w a a a a a a a a \V w a a a w w a w-a w w a W w-a a w-a Sulphate A-I w w w-a W” w w» W-A w i w w Sulphid A a a a A13 A >3 w a 21 w w a22 A 22 A 23 Tartrate a w-a w-a w-a a a w a W a a a 15 MnOa = sol. in HC1; insol. in HN03. 16 Mercurammonium ehlorid = A, 11 Basic sulphate = A. 18 HgS = insol. in HC1 and in HN03, sol. in aq. regia. 19 See IB. 20 PtKCls = W-A. 21 Only soluble in HN03. 22 Sn sulphides = sol. in hot HC1; oxidized, not dissolved, by HN03. Sublimed SnCh only sol. in aq. regia. 23 Easily sol. in HN03, difficultly in HC1. Au3S = insol. in HC1 and in HN03, sol. in aq. regia. AuBr3, AuC13, and Au(CN)3 = \v ; Aul3 = a. PtS3 = insol. in HC1, slightly sol. in hot HN03; sol. in aq. regia. PtBr4, PtCh, Pt(CN)4, PtCN 03)4, (C304)3Pt, Pt(S04)3 = w ; Pt03 = a ; Ptl4 = i. 504 MANUAL OF CHEMISTRY. TABLE II.—WEIGHTS AND MEASURES. 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. MEASURES OF LENGTH. Inch. Millimetres. A = 0.3819 A = 0.7638 A = 1-5875 i = 3.175 i = 6.35 i = 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 “ “ TTl. 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 21 = 1.29 22 = 1.36 23 = 1.42 24 = 1.48 25 = 1.54 Til. C.C. 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 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 TTl. C.C. 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. 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 FI 5. c.c. 5 = 147.81 6 = 177.39 7 = 206.96 8 = 236.53 9 = 266.10 10 = 295.68 11 = 325.25 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 WEIGHTS AND MEASURES. 505 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. A = o.ooi A = 0.002 A = 0.004 | = 0.008 i = 0.016 i = 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 drains. 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 55 = 3.564 56 = 3.629 57 = 3.694 58 = 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 I Grams. 1 = 31.103 2 = 62.207 3 =' 93.310 4 = 124.414 5 = 155.517 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 = 3.733 506 MANUAL OF CHEMISTRY. 720 722 724 726 728 730 732 734 736 738 740 742 744 f 10° 1.1388 1.1370 1.1402 1.1434 1.1466 1.1498 1.1529 1.1561 1.1593 1.1625 1.1657 1.1689 1.1721 © 11° 1.1288 1.1320 1.1352 1.1384 1.1415 1.1447 1.1479 1.1511 1.1542 1.1574 1.1606 1.1638 1.1670 "3 12° 1.1237 1.1269 1.1301 1.1333 1.1364 1.1396 1.1428 1.1459 1.1491 1.1523 1.1554 1.1586 1.1618 JiC 13° 1.1187 1.1219 1.1251 1.1282 1.1314 1.1345 1.1377 1.1409 1.1440 1.1472 1.1503 1.1535 1.1566 14° 1.1136 1.1168 1.1200 1.1231 1.1263 1.1294 1.1326 1.1357 1.1389 1.1420 1.1452 1.1483 1.1515 © 15" 1.1085 1.1117 1.1149 1.1180 1.1211 1.1243 1.1274 1.1305 1.1337 1.1368 1.1399 1.1431 1.1462 O 16° 1.1034 1.1066 1.1097 1.1128 1.1160 1.1191 1.1222 1.1253 1.1285 1.1316 1.1347 1.1378 1.1409 .S 17° 1.0983 1.1014 1.1045 1.1076 1.1107 1.1138 1.1170 1.1201 1.1232 1.1263 1.1294 1.1325 1.1356 © 18° 1.0930 1.0961 1.0992 1.1023 1.1054 1.1085 1.1117 1.1148 1.1179 1.1209 1.1241 1 1272 1.1303 3 19" 1.0877 1.0908 1.0939 1.0970 1.1001 1.1032 1.1063 1.1094 1.1125 1.1156 1.1187 1.1218 1.1248 <3 20° 1.0825 1.0855 1.0886 1.0917 1.0948 1.0979 1.1009 1.1040 1.1071 1.1102 1.1138 1.1164 1.1194 U P> P §oo^totoosoa^*iitt®TC5Cs-a-^ P X —LHu-—LH-J-h-^t—^H-i- O^-*W(0M^4^CiCl0:Ci-l^(XQ0 Cl p CS*OQOCOCD4POC*p^OP^DOO CiWO^CCOOMODMOOM^OCO pMKpppKPpfaMPMPPfa Cl 1 Oi ©i~‘-tCfcSCOO3rf^^ata»C5~J-^ja0a0© CC CT C5 iC 05 a t!iCei-*ODt^C>^®M-^©i®~5l®aOiCaCCO©>fe. O^HOCl^OOIO^OOKOI^OM^ Cl 3C X -1 V* H^fcOtOCOCO*>.^OlOSOS“a-QOOQD«e«D C Ci^tocwTMCi^iTCCccicoH-^c: C | U-l _ — ,_L _. -1 •4 V* LC MtOCSCClf>-4i.tlC1®a—© — ~J -i 5* 1 W* a ; [ h-i. pP pP pa. *-L pp pp t-1 H-. I-P M PP HP HP I -i w m k n w a a -j x qc ® ® c X