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ELEMENTS OF CHEMISTRY

AND

DENTAL MATERIA MEDICA

BY

J. S. CASSIDY, D.D.S., M.D

Pkofessok of Chemistry and Materia Medica in Ohio College of

Dental Surgery

CINCINNATI ROBERT CLARKE & CO

1893

COPYKIGHT, 1892,

By JAMES S. CASSIDY.

TO

ELIZA GUYTOE",

IN LOVINO APPRECIATION OF HER

CHRISTIAN FORTITUDE

AND

EXCEEDING PATIENCE

UNDER MANY TRYINO CIRCUMSTANCES,

Stbis ^ook is ^ffettionattlg ^nstribtb,

BY HER HUSBAND,

THE AUTHOR.

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PREFACE.

The labor involved in the preparation of the fol- lowing pages, was assumed at the solicitation of members of my classes; and also for the purpose of testing the comparative value, to Dental Stu- dents, of the two approved didactic methods of teaching Chemistry and Materia Medica, i, e., by

Lectures and quiz, and by Recitation from approved Text-books, in connection with suggestive experi- ments.

The author lays no claim to originality of style, or system, in presenting the subjects. The sub- jects themselves, with few exceptions, are not elas- tic, and admit of only slight variations from the usual accepted phraseology.

Division of the volume into Three Parts was made, with a view to the convenience of the three graded classes, which now obtain, as required by the Association of Dental Faculties.

The space given to the consideration of Chemi- cal Philosophy, and Compound Radicals, as well as that occupied by the few simple rules to be observed in Prescription writing, Hud the approximate re-

vi Preface.

lations between the Metric, and Apothecaries sys- tems, of weights and measures, will, not, I trust, he regarded as superfluous; for dental students, as well as those of medicine, are often sadly deficient in a clear knowledge of those important accom- plishments.

It may appear on first sight, that our Materia Medica is too limited, and overshadowed by the governing science of Chemistry; but the combina- tion of these two branches of our curriculum, as herein presented — which I believe is unique, and to the advantage of the student — necessarily pre- vents the complete exposition of at least those drugs which are unessential in dental practice.

Description of the work performed by the class, in our Chemical Laboratory, on Qualitative Analy- sis, lias been omitted, inasmuch as a monograph on that subject, will probably soon be forthcoming.

I have, of necessity, borrowed freely from the authorities consulted, to all of whom it would be impossible to give individual credit. Of these^ however, we must not forget the collective credit due to various dental, medical, and scientific jour- nals, and in especial manner to Fowne's, Atfield's, Clark's, Appleton's, Mitchell's Dental, Roscoe's, Crooke's, ai'Ui/:Barket!^;/<vhen:dstry ; Miller's Mi- crobes, and Biddre^s, Polter^^, (jforgas.'. Dental, Bar-

Preface. vii

tholow's, Farquharson's, and Waring's Materia Medica. To tliem, and many other friends, who have assisted to render my task a labor of love, I hereby extend my grateful acknowledgments.

J. S. CASSIDY,

1555 Madison Avenue, Covington, Ky., December 15, 1892.

Note. — By kindly referring to the Index, the reader will observe a slight departure from the usual orthography of cer- tain words. Thus will be found Chlori>2, lodni, Glycerin, Cocam, Oxid, SuJfur, etc.

This innovation is in accord with the recent official report of a Committee of the Chemical Section of the American Associ- ation for the Ads^ancement of Science, and will probably be generally adopted in the very near future. J, S. C.

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INORGANIC CHEMISTRY.

PAR^T FIRST.

CHAPTER I. PHYSICS.

Matter and Force are involved in the consider- ation of all natural phenomena.

Matter, substance, of which the physical uni- verse is composed.

Force, modes of motion by which are manifested heat, light, magnetism, and electricity; also motor, or mechanical motion. All of these are inter-con- vertible.

Specific gravity. Special kinds of matter, as water, chloroform, gold, etc., differ from each other in Aveight; or equal bulks of them are not affected equally by the attraction of gravitation. They differ therefore in specific gravity, or in the force with which they fall to the earth.

The specific gravity of any substance is its loeight compared with the weight of an equal bulk of the stand- dard substance reckoned as unity.

In the case of all solids and liquids, distilled water at a temperature of 4°C. (39°F.), is the stand-

(1)

2 ^ Inorganic Chemistiy.

ard of unity. A given temperature is necessary, inasmuch as change, in this respect, either in- creases or decreases the volume. The specific gravity of any liquid is ascerfained by dividing its weight, at the standard temperature, by the weight of an equal bulk of water. The quotient will be greater or less than unity, according as the weight of the liquid in question, is greater or less than that of the standard.

The specific gravity of a solid is obtained by the same rule, viz., divide the weight of the solid by the weight of the same bulk of the standard (water). If the solid be heavier than water, it is first weighed in air, then in water; it thus weighs less in water than in air, and the loss in weight expresses the weight of its own bulk of the liquid. Its weight in air is divided by the amount it loses by immersion in water; the quotient will be the specific gravity of the solid.

When the solid body is soluble in water, then some non-solvent liquid, the specific gravity of which is known, is taken as a substitute.

In determining the specific gravity of a solid lighter than water, various methods are employed. A piece of metal, for instance, may be attached to overcome the buoyancy of the light body, and mathematical results thus obtained.

Physics. S

A sufficiently exact key to the general doctrine . of the e([uilibrium of floating bodies is afl:brded by the theorem of Archimedes.

A solid of less specific gravity than the liquid in which it is placed will float. It displaces, at the same time, a quantity of liquid exactly equal to its own weight. Thus, a solid possessing one-half the specific gravity of water, if placed in that liquid, will sink one-half its bulk, the weight of the water displaced, l)eing equal to the weight in air of the floating body.

It is on this principle that instruments known as hydrometers, urinometers, etc., are constructed, by which a graduated stem, made of glass or metal, floats in the liquid to be tested. If the liquid be heavier than unity, the stem will be raised accordingly, and vice versa, with liquids lighter than water. The specific gravity of the rKpiid will he indicated by the coincidence of its surface with the figures on the graduated scale.

The specific weights of gases are obtained by dividing their weight by an equal volume of air. In many cases hydrogen is taken as the standard of unity for gases. The term dejisitij, when ap- jdiod to a gas, implies that hydroiren is reckoned as unity, and when the term specific gravity is em-

4 Inorganic Chemistry.

ployed with reference to the same, or some other gas, it is understood that air is the standard of unity.

PROPERTIES OF GASES.

G-ases or vapors, whether simple or compound, are obviously affected by the attraction of gravita- tion, in common with other forms of matter.

The atmosphere is the familiar prototype of gases in general, and serves to exhibit certain phe- nomena pertaining to all of them ; one of which is the property of elasticity.

Air contained in a cylinder, in which works an air-tight piston suffers condensation, if the piston be pressed down ; whereas, if the pressure be less- ened by raising the piston, the air will expand and completely fill the enlarged space in the cylinder.

The volume of a given weight of gas depends on the pressure : the relation being expressed by the law of Mariotte, " The volume of a gas is in- versely as the pressure ; the density and elastic force are directly as the pressure and inversely as the volume." Thus, 100 cubic inches of gas at the ordinary pressure, will expand to 200 cubic inches, if the pressure be reduced one-half, and shrink to a volume of 50 cubic inches if the pressure be doubled.

The atmosphere is the ocean of gaseous matter surrounding the earth and held to the latter by the

Physics. 5

attraction of gravitation. Its weight, or density, is therefore greater at the sea level, than at high elevations; the density decreasing uniformly as we ascend.

Instruments to indicate changes in the weight, or pressure of the atmosphere at different eleva- tions, or temporary changes in the pressure at a given elevation, are called barometers.

The mercurial barometer is constructed by filling completely, a glass tube about 35 inches long with clean, dry mercury, and the open end of the tube inverted in a reservoir of mercury. It will then be seen that the mercurial column will descend in the tube — leaving an empty space above — until it reaches a position about 30 inches above the sur- face of the mercury in the reservoir, at which point it remains balanced by the pressure of the atmos- phere. Now, if such a column of mercury, having an area of 1 inch, be weighed, it will be found to weigh between 14 and 15 lbs., proving that the pressure of the atmosphere is nearly 15 lbs. on every inch of the earth's surface.

The diffusive poicer of gases, depends on their rel- ative densities; the rule being that " the diffusive power of a gas is inversely as the square root of its density." If a vessel be divided in two equal com- partments by a thin, dry partition of plaster of

6 Inorganic Chemistry.

paris, and the two compartments filled with differ- ent gases, incapable of acting chemically on each other at ordinary temperatures, it will be found that diffusion into each other will take place according to the above rule.

If one compartment be filled with H, and the other with 0, 4 cubic inches of H will pass through the porous plaster of paris diaphragm, to the oxygen side, while 1 cubic inch of 0 will pass to the 11 side. The densities of these two gases are as 1 to 16; their relative rates of dift'usion, are inversely as the square roots of these numbers, or as 4 to 1.

The inherent diffusive power of gases, whereby the atmosphere absorbs them, prevents the accu- mulation of poisonous vapors in confined localities, their wide dissemination permitting the atmospheric ozone to destroy them easily ; or they become so at- tenuated in the air, as is the case with carbon-diox- ide, ammonia, etc., that they exert no appreciable influence on the health of the animal kingdom. Certain gases, though comparatively dense, diffuse most readily through wet membranes on account of ■ their great solubility ; as in the process of animal respiration, the CO2, which is freely soluble in water, escapes easily thus dissolved, through the wet membranes of the lungs.

Effects of Heat.

CHAPTER II.

EFFECTS OF HEAT.

One of the most general eiFects produced on matter, by increasing temperature, is expansion. If a metallic bar be fitted accurately to a guage when cold, and then slightly heated, it will be found too long to enter the gauge. This is due to the heat overcoming to that extent the attraction of cohesion existing between the molecules of the bar. If the heat be continued, the molecules may be driven so far apart, that the metal will assume the liquid state; and, finally, the metal may be made to volatilize, or become gaseous, in which condition, the molecules are widely separated. By abstracting the heat, or allowing the mass to cool, contraction takes place ; the space between the mol- ecules is lessened, the metallic vapor changes again to a liquid, and this back to the original solid con- dition. The expansibility of most solids varies with the increment of heat, zinc, lead, silver, cop- per, gold, soft iron, tempered steel, untempered steel, common white glass, platinum and flint glass, expand in the order named.

8 Inorganic Chemistry.

It is seen that glass and platinum expand and contract, nearly alike, and porcelain, whose nature and expansive power approximates the former ma- terial, permits fusion with platinum in the manu- facture of artificial teeth, Logan crowns, etc., with- out the danger of fracture, by excessive changes in temperature.

Liquids not only differ in dilation by equal amounts of heat, but they differ greatly in their rate of expansion, by increasing temperature.

Mercury expands more uniformly between 0°C, and 100°C, than other liquids, and for this reason it is employed in the construction of thermome- ters, instruments for measuring changes in tem- perature. A glass tube closed at one end and blown to a bulb, the other end left open and drawn to a point, is partially filled \vith mercury. The bulb is carefully heated, by which the air is driven out, the tube being completely filled with the ex- panded mercury ; the open end is then hermetically sealed, and on cooling, the mercury contracts, leaving an empty space above. The height of the mercurial column is marked on the glass, at two fixed points. These two points are found at the boiling temperature of water, the barometric pres- sure being noted, and at the freezing of water, which is constant. Between these two marks, the

Effects of Heat. 9

tube is divided into an arbitrary number of degrees, the scale continuing above and below each mark respectively, to indicate temperatures above and below the boiling and freezing points of water. The Raumer scale is divided into 80 degrees; the boiling point at 80°, the freezing point at 0°. Fah- renheit's scale contains 180 degrees, but he placed his 0°, 32 degrees below the freezing point; conse- quently the boiling point is expressed by Fahren- heit at 212°. According to the centegrade ther- mometer, the freezing of water is* indicated by 0°, and the boiling point by 100°. The graduation of the latter instrument is considered the most ra- tional. It is adopted by nearly all scientific bodies. Fresh water when subjected to the freezing pro- cess continues to contract in volume until it reaches a temperature of 4°C, (-SO^F) — its point of maxi- mum density. On further cooling it expands, until the freezing temperature is reached, 0°C, (32°F.) In the immediate act of solidifying, great enlarge- ment takes place : ice is therefore formed on the surface, being lighter than the liquid water beneath. On melting, the reverse takes place; the volume contracting until the temperature of 4°C is reached, after which expansion proceeds with increasing heat. In regard to the expansion of gases by heat, the following statement will suffice :

10 Inorganic Chemistry.

I. All gases or vapors when remote from their condensing points, expand nearly alike for equal increments of heat.

II. The rate of expansion is uniform for all de- grees of heat.

III. The rate of expansion is not altered by a change in the state of compression or elastic force of the gas itself.

IV. The actual amount of expansion is equal to

1 1

3QQQ of the volume of the gas at 0°C, for each degree of that scale : 3,000 volumes of gas at 0°C become 3,011 at 1°C, 3,022 volumes at 2°C, etc.

CONDUCTION OF HEAT.

The power of conducting heat varies greatly with different bodies. If rods of the same size of differ- ent solids have each one extremity heated equally, the other extremities will become heated in the ratio of the conducting power of the material.

The metals as a class are the best conductors of heat (and electricity), silver being first. Rating the conducting power for silver at 1,000 that of

Copper is 736

Gold is 532

Tin is 145

Iron is 119

Effects of Heat. 11

Lead is 85

Platinum is 84

Normal Moist Dentine is 15

Gold, and mercurial alloys of copper, and of silver and tin — known as amalgams — are much better con- ductors of heat than tooth structure, and to that extent, at least, are objectionable materials for fill- ing cavities in teeth. Tn sudden thermal changes in the mouth, heat is conducted by them so rapidly to or from the dental pulp, as to endanger the com- fort and life of that organ.

Various other solids, mainly non-metallic, such as glass, wood, vulcanite, gutta-percha, zinc ox- ide cements, etc., are poor conductors. The last two substances are frequently employed singly and sometimes in union, as a protecting covering to the pulp, before applying the metallic tilling.

Liquids and gases are classed as non-conductors of heat; their increase in temperature is due to convection, or the circulation of their particles within the mass. Those particles nearest to the source of artificial heat move away, giving place to others of lower temperature, until all the par- ticles acted upon are involved in the heating process.

12 Inorganic Chemistry.

CHAPTEK III.

SPECIFIC HEAT.

Equal weights of different substances require different amounts of beat to raise tbem a given temperature. If 1 lb. of water at 40°C., and 1 lb. of water at 10°C., be mixed, the mixture will pos- sess the mean temperature of both, or 25°C. If 1 lb. of mercury at 40°C. be mixed with 1 lb. of mer- cury at 10°C., the mixture will also possess a tem- perature the mean of 40 and 10, or 25°C. IsTow, if 1 lb. of water, at 40°C., be mixed with 1 lb. of mer- cury at 10°C., the temperature will not be 25°C., but will be 39°C. The lb. of water at 40°C. loses but 1° in cooling from 40° to 39°, while it raises its own weight of mercury 29°, from 10° to 39° ; the specific heat, i. e., calorific capacity of water is, therefore, 29 times greater than mercury. The amount of heat sufficient to raise a given weight of water through a given range of temperature, referred relatively to the amount of heat required to raise equal weights of the different substances through the same range of temperature, implies tlie spe- cific heats — capacities for heat — of the various

Specific Heat. 13

substances. The specific beat of water is greater tlian that of any other substance, excepting hy- drogen. Taking water as unity — 1,000 — the ca- pacity for heat, of an equal weight of hydrogen, is expressed by 3.490, and gold by 0.324.

But if, instead of equal weights, quantities pro- portional to the atomic weights of elements be taken, there will be found a remarkable relation, viz : " The atomic weights of the various elements are inversely proportional to the specific heats, so that the product of the specific heats into the atomic weights is approximately a constant num- ber. The same quantity of heat will produce a given change of temperature in 7 grains of Li., 56 of Fe, 108 of Ag, 197 of Au, etc. These numbers represent the atomic weights of the elements named. In other words, the atoms of the several elements have equal capacities for heat.

Latent Heat. — Whenever a solid melts or fuses a certain amount of sensible heat disappears and remains latent in the liquid.

One lb. of powdered ice or snow, at 0°C., placed in 1 11). of water at 70C. will melt; the tempera- ture, however, will not be 35°C. — the mean of 70° and 0° — but will be reduced to 0°C. by the melting of the ice, showing that 70°C. of heat have been

14 Inorganic Chemistry.

absorbed in the chanofe of state from solid to

liquid.

1 lb. of water at 70°C. 1 lb. of ice at 0°C.

This heat of fluidity is set free, when the water again freezes; for, although the temperature of the surrounding medium may be much lower than the freezing point of water, so much latent heat is set free by the change of state from liquid to solid, as to keep the temperature up to 0°C.

This law of sensible heat becoming latent, when- ever any solid becomes a liquid, also applies to solids and liquids becoming gases, a certain amount of heat disappears and remains latent in the gas; and heat, to an exactly corresponding amount is set free, when the gas again assumes the liquid state.

A pound of water at lOO^C. mixed with a pound of w^ater at 0°C., will occasion a temperature in the mixture of 50°C., but a pound of steam at 100°C., if condensed to a liquid in water at 0°C., will, by giving up its latent heat, confer a temper- ature equal to its own of 100°C. on 5.4 pounds of water at 0°C. It follows, that temperature is less- ened by change of state from solid to liquid, and from liquid to vapor. Fahrenheit mixed powdered ice and salt : the mixture became liquid and re-

Specific Heat. 15

duced the temperature 32°F. (by his scale) below the freezing point of water. He supposed this to be the greatest absence of heat that could be arti- ficially produced, and named the point zero (0°F.)

Ordinary chemical action always occasions a rise in temperature ; but mere solutions generally lower the temperature because of the amount of heat ab- sorbed overcoming the heat developed by weak chemical affinities. This is the principle of frigo- rilic mixtures, such as powered calcium chloride and snow; ammonium nitrate and water, etc.

The great reduction of temperature occasioned by the rapid evaporation of highly volatile liquids, such as ethyl chloride, ethyl oxide, etc., is due to the heat absorbed and which remains latent in the escaping vapor. In minor surgical operations, some of these highly volatile liquids are applied to the part, in the form of a spray, to obtund sensibility.

Water evaporates at all temperatures, and, as with other liquids, its evaporation is increased by increase of heat. 'When the boiling point is reached there is visible formation in the body of the liquid of bubbles of gas, which ascend to the surface and escape into the atmosphere as vapor, carrying the latent heat with them, thus prevent- ing the liquid from assuming a higher tempera-

16

Inorganic Chemistry.

tare. Water (or otlier liquid) boils, when the elasticity of its vapor is able to overcome the pres- sure upon it.

At the sea level water boils at 100°G., (212°F.), but, at higher elevations, as on mountain tops, ebul- lition takes place at a lower temperature, because of the lessened pressure, or weight of the atmos- phere. If water be made to boil in a partially filled flask, the vessel then tightly corked and re- moved from the source of heat, the boiling of the water will soon cease by the pressure of its own inclosed vapor. By applying to the surface of the vessel a wet sponge, which condenses the vapor and thus diminishes the pressure, ebullition again takes place; and this repeatedly, until the water in the flask is reduced to a common temperature.

Distillation, 17

CHAPTER IV.

DISTILLATION.

The object of distillation is either to separate different substances which rise in vapor, at differ- ent temperatures, from a composite liquid, or to part volatile liquids from substances that do not volatilize. When the process applies to solid bodies passing directly to the gaseous state and back again to the solid form, it is called sublimation.

Liquids evaporate at temperatures below the boil- ing points, and the vapors thus escaping, as in the case of water from the ocean and from the general surface of the earth, are virtually distilled.

Vapor of water exists in the atmosphere at all times and in all situations. If the aqueous vapor he in condition of greatest possible density for the temperature, or as is often but incorrectly ex- pressed, the air be saturated with vapor of water, the slightest reduction of temperature will cause the deposition of a portion in the liquid form. If, however, the vapor of water be below the point of maximum density, that is, in an expanded condi: tion, which is generally the case, a considerable

18 Inorganic Chemistry.

fall of temperature may occur before the dew. point, or liquefaction commences. The resemblance be- tween vapors, and what are ordinarily known as gases suggested means by which all of the latter class have been converted into liquids, by the influ- ence of cold combined with pressure. Thus, chlo- rine gas at a pressure of 4 atmospheres and a tem- perature of 15.5°C., and nitrous oxide gas at a pressure of 50 atmospheres and a temperature of 7.2°C., are condensed to the liquid state.

Nature of Heat. — Although the sources of heat are numerous, such as the sun itself, the interior of the earth, mechanical motion (the latter includ- ing percussion, friction and condensation), electric excitation and chemical action, a rise in tempera- ture is caused in all cases by increased motions in- duced in the particles of matter involved in its development. It is probable that absolute zero or perfect absence of molecular motion, does not ex- ist. That matter changing from the gaseous to the liquid, and on to the solid state, is owing to a lessening in the molecular and atomic motion, con- sequent on the withdrawal of a corresponding equivalent of heat, and vice versa.

Light.— Rays of light, the effect of undulating motion, projected from a luminous body, either ce- lestial or terrestrial, while passing through homo-

Distillation.

19

geneous diaphanous media, travel in straight lines, and with great velocity. If, however, the media through which the light passes, should vary in density, the ray of light will be changed in direc- iion, will he bent from a continuous straight line ; in short, refracted. The rale of simple refractio.n of light is stated thus: lohen a ray of light loasses from a rare through a denser medium, it is bent toward, a line draivn perpendicular to the surface of the lat- ter, and when passing from a dense to a rarer me- dium it is bent from the perpendicular line, and takes a direction parallel with a continuation of its former course, provided the medium be the same before and after refraction.

f	I /A
// // / / / / B/ /
/C

Tf the incident ray of light, /, fall upon the plate ghiss, A, at the angle shown, then instead of pass- ing straight through tlu; glass to J3, it will be bent toward the perpendicular line P to C, and on

20

Inorganic Chemistry.

emerging again into the air at C, it will be bent from the perpendicular line, assuming a direction parallel to its former course. It is upon this prin- ciple that prisms and lenses depend. Convex sur- faces converging the refracted rays, and concave separating them more widely. In case the refract- ing substances should be prismatic in form instead of possessing parallel sides like plate glass, the ray of light will be refracted as described, and also de- composed into colors of different refrangibility. (See spectrum analysis.)

If a ray of sunlight A be admitted into a dark room and allowed to pass through a glass prism at jB, the light is refracted; and if thrown on a white screen (7, it will be seen to consist of several colors, which form what is known as the solar spectrum, and also as the primary colors. These colors and their various shades are dependent on

I

Dislillation. 21

mathematical perception. The red color is dis- tingiiished as such, because the vibrations of light, producing it are received by the retina of the eye, at the rate, in round numbers, of about 450 mil- lion million times a second, and the violet at about 785 million million times a second. The interme- diate colors and the infinite number of tints ac- companying them are due to the variations in the number of vibrations received by the normal hu- man retina. Hence, color-blindness is owing to the inability of the retina to receive a given num- ber of vibrations within a given time. The solar spectrum is often divided into three different parts ; the most refrangible colors are known as the blue rays, the richest in chemical influence; the least re- frangible, or red, the heat rays, and the intermedi- ate colors, the light rays. An invisible ray, more refrangible than the violet, is richer in actinic power than the latter, and a ray, also invisible, less refrangible than any, possesses greater heating power than the red.

Reflection of Light. — When a ray of light falls upon surfaces, it is either absorbed and thus it more or less disappears; or, it suffers reflection and thus assumes a new direction. The law of the re- flection of light is simply stated.

22

Inorganic Chemistry.

When a ray of light, J, falls upon a polished surface, A, at a certain angle, it is reflected in the direction of R, which makes an angle with the per- pendicular line, P, equal to the angle of incidence. In other words, the angles of incidence and reflec- tion are equal.

R P I

Almost all things upon the general surface of the earth, incline toward each other at promiscu- ous angles, and so reflect the liglit diffused. It is by means of this diffused reflected ligiit that we are enabled to perceive objects distinctly. The color of an object is due to its ability to reflect the special rays or combination of them, by which it is distinguished. A white object reflects all the rays of light that fall upon it, while black absorbs all, and reflects none.

Radiant Heat. — A few salient features of ra- diant heat may be properly considered as an ac- companiment to our studies of the nature of light.

When a hot body has its source of heat with- drawn, it begins to cool immediately. It loses heat in three ways.

Distillation. 28

1st. By conduction ; by means of the support upon which it rests.

2nd. By convection ; the particles of air sur- rounding the heated body, move away, carrying their modicum of heat with them, and giving place to other, colder, particles of air, which also become heated and move away, and so on, all in accordance with the law of hydrostatics.

3rd. By radiation ; a portion of heat escapes by vibration in all directions from the heated body. It meets with no interference from the air, and suf- fers absorption and reflection, by surrounding bod- ies, like rays of light.

In fixct, radiant heat resembles light in many re- spects ; it travels with great velocity ; it is reflected from surfaces ; it enters and traverses certain media, undergoing at the same time refraction, ab- sorption, and polarization, obeying in these re- spects the same laws which regulate the corres- ponding phenomena of light. Polished concave surfaces will therefore reflect and concentrate the heat rays to a focus, while convex surfaces will cause them to diverge. Smooth, bright surfaces reflect nearly all the heat that falls upon them, and thus reniain cool; dark, rough surfaces, on the contrary, soon become heated, by absorbing the ra- diant heat, and reflecting scarcely any. Good re-

24 Inorganic Chemistry.

flectors are poor absorbers of heat, and vice versa. The power of absorbing and of radiating heat, is in direct proportion. The surface \^ihich absorbs heat most perfectly, will when heated, also radiate most perfectly. If two vessels of equal size and material, one having a polished w^hite surface, the other a dark, rough surface, be filled with hot water, the rate of cooling by radiation will be un- equal ; the water in the latter vessel will lose its heat more rapidly than that in the one wdth the polished surface. Hence, the dental pulp when protected by a highly polished filling is not so much affected by thermal changes, as it would be in case the surface of the filling is roughly finished. On this principle also, investments of artificial teeth should be smoothly finished in order to prevent un- due radiation of heat from the surface during the process of soldering. At the same time, much heat will be economized, if the blow-pipe flame be thrown in such direction as to compel the reflected heat to strike only some part of the investment.

Constitution of Matter. 26

CHAPTER Y.

CONSTITUTION OP MATTEK.

All kinds of matter may be divided into single or elementary and compound forms. A compound con- sists of two or more elements united together in certain proportions. An acquaintance therefore with the names of the several elements symbolized by certain letters, and their atomic weights, or pro- portions in which they unite to form compounds, is necessary^ to the beginning of chemical studies. The following table is presented for this purpose :

CONSTITUTION OF MATTER. NAME. SYMBOL. - ATOMIC WEIGHT.

Aluminum Al 27

Arsenic .*.... As 75

Antimony Sb. (Stibium) 120

Boron B 11

Bromine Br 80

Barium Ba 137

Bismuth Bi 208

Carbon C 12

Chlorine CI 35-5

Calcium Ca 40

3

26 Inorganic Chemistry.

NAME. SYMBOL. ATOMIC WEIGHT.

Chromium Cr 52

Cobalt Co 59

Copper Cu. (Cuprum) 63-3

Colurabium Cb 94

Cadmium Cd 112

Caesium Cs 133

Cerium , Ce 141

Didymium Di 142-3

Decipium Dp

Erbium Er 166

Flourine F 19

Glucinum Gl 9

Gallium Ga 69

Gold Au. (Aurum) 196-5

Hydrogen H. = 1

Iron Fe. (Ferrum) 56

Indium In 113-6

Iodine 1 127

Iridium Ir 193

Lithi u m Li 7

Lanthanum La 138-2

Lead Pb. (Plumbum) 207

Magnesium Mg 24

Manganese Mn 55

Molybdenum Mo 96

Mercury Hg. (Hydrargyrum).. 200

Nitrogen N 14

Constitution of Matter. 27

NAME. SYMBOL. ATOMIC WEIGHT.

Nickel Ni 58

Oxygen O 16

Osmium Os 198

Phosphorus P 31

Potassium K. (Kalium) 39

Platinum Pt 195

Kubidium Rb 85-5

Ruthenium. Ru 104

Rhodium Rh 104

Sodium Na. (Natrium) 23

Silicon Si 28

Sulphur S 32

Scandium Sc 44

Selenium Se 79

Strontium Sr 87-5

Silver Ag. (Argeutum) 108

Titanium Ti 48

Tin Sn. (Stannum) 118

Tellurium Te 126

Terbium Tb

Tantalum Ta 182-6

Tungsten W. (Wolfram) 184

Thulium Tm

Thallium Tl 204

Thorium Th 232

Uranium U 239

Vanadium V 51-5

28 Inorganic Chemistry,

NAME. SYMBOL. ATOMIC WEIGHT.

Yttrium Yt 89

Ytterbium Yb 173

Zinc Zn 65

Zirconium Zr 90

For convenience of description, matter is divided into three physical conditions ; namely, Solids, Li- quids and Gases.

Gold and marble are examples of solids ; ordinary water and the oils, of liquids; and the atmosphere and nitrous oxide, of gases.

Each of these physical conditions is sub-divided into masses y molecules and atoms.

A mass of matter is any quantity of matter ap- preciable to the senses. A molecule is the smallest particle of matter that can exist without losing its identity. An atom is the still smaller particle of matter obtained by division of a molecule. The earth and a grain of sand are equally masses of matter. The molecules of marble, consisting of the metal calcium, and the non-metal carbon, and the gas oxygen ; and the molecule of nitrous oxide, composed of the two gasses, nitrogen and oxygen, may be split up by chemical means into their con- stituent atoms. From the molecule of marble the individual atoms of calcium, carbon, and oxygen;

Constitution of Matter. 29

and from the molecule of nitrous oxide, nitrogen and oxygen can be obtained.

The atoms of calcium, carbon, and oxygen, in marble ; and of nitrogen, and oxygen, in nitrous oxide, can not be further separated into simpler forms. An atom itself is indivisible.

Chemical action involves the play of selective affinities at given temperatures, between the con- stituent atoms only, of the acting substances.

The force of attraction exerted on the above three divisions of matter is threefold.

The attraction of gravitation between masses of matter. The earth and other planets are held to the sun, and the grain of sand to the earth, by the attraction of gravitation. The attraction be- tween homogeneous molecules, as those of marble, gold, etc., is called cohesion, while that which holds the atoms together to form the molecule is called chemism, chemical attraction or chemical affinity. The latter form of attraction is considered as closely allied to the electric condition. As a class, the atoms of the non-metallic elements, as oxygen, sulphur, iodine, etc., are electro-negative, those of the metallic elements, like silver, calcium and po- tassium, are electro-positive. These two classes are strongly attractive toward each other, while the atoms of those elements intermediate between

30 Inorganic Chemistry.

the non-metallic and metallic elements, such as arsenic, antimony, etc., will combine readily with the atoms of either the negative or positive kind. A molecule may he defined as consisting of a definite number of atoms. A simple molecule being made up of atoms of the same kind, as, for example, a molecule of hydrogen, H-H; or of oxygen, 0=0 ; or of ozone, ^^ A compound molecule contains two or more atoms of different kinds, as water H,0, or marble CaCO,. These facts are ascertained by analysis and synthesis.

Analysis, which separates the constituent ele- ments in compounds, and synthesis, which recom- bines the elements to form compounds. From a mass oi simple molecules only simple matter comes, but from a mass of compound molecules, simple matter is obtained.

From a mass of gold nothing but gold can be obtained. Gold is, therefore, a simple form of matter, or is an element. Water H,0, on the contrary, is a compound, because by analysis it gives np two diflierent substances, hydrogen and oxygen ; but all efforts to divide either hydrogen or oxygen into simpler forms fail ; they still remain hydrogen and oxygen. They are, therefore, each elementary.

Notation and Nomenclature. 31

CHAPTER YL

CHEMICAL NOTATION AND NOMENCLATUEE.

The letters, symbols — H, 0, or IN", etc., in the table, on p. 26, 27, not only indicate the presence of hydrogen, oxygen, nitrogen, etc., respectively, but also certain quantities by weight of each, pro- portional to their atomic weight.

Thus, the letter H symbolizes hydrogen, and at the same time indicates 1 part by weight of hy- drogen. Hydrogen being the lightest substance known, the weight of its atom is taken as unity. The letter 0, one atom, or 16 parts by weight of oxygen. The letter N, one atom, or 14 parts by weight of nitrogen, etc.

Combination between elements to form com- pound molecules — which latter suggest a propor- tional weight of a mass of the given compound — is represented by placing the symbols in immediate juxtaposition. Thus, HCl is a compound-mole- cule— consisting of one atom, or 1 part by weight of hydrogen, united to one atom, or 35 — 5 parts by weight of chlorine. When there are more than one atom of a certain element forming the mole-

32 Inorganic Chemistry.

cule, the appropriate figure is placed to the right and a little below the symbol. The molecule of water contains two atoms of hydrogen and one of oxygen ; the formula for water is, therefore, II2O. The formula of peroxide of hydrogen, which con- tains two atoms of hydrogen and two atoms of oxygen is written H2O2. When it is necessary to multiply the molecule itself, the figure is placed to the left, and on a line with the first symbol. The formula 2H2O, means two molecules of water. Sometimes when the molecule is somewhat com- plicated, it is inclosed in brackets, and if multi- plied, the figure is placed either to the left and on a line, or to the right and a little below. Thus, 3(ISrH4Cl) or (NH4C1)3 represents three molecules of a certain compound, each molecule containing 4 atoms of hydrogen, 1 atom of nitrogen, and 1 atom of chlorine. These few examples will suffice for similar explanation of all other formulae.

In chemical changes every atom of each element involved, must be accounted for. This is done by placing the formulae of the reacting bodies first, with a plus mark between them, followed by a sign of equality and then the formulae of the bodies produced by the change, with a plus mark be- tween them. All of which constitutes a chemical equation :

Notation and Nomenclature. 33

2IIC1 + Na2C03 = 2:N'aCl + ll^O + CO2

Hydroj^en Sodium Sodium Hydrogeu Carbon

Chloride. Carbonate. • Chloride. Monoxide. Dioxide.

The above equation is also an illustration of wliat is termed double decomposition and recom- position. Two molecules of hydrogen chloride, and one molecule of sodium carbonate react upon each other by means of the mutual affinities between their atoms. The 2 atoms of hydrogen take one atom from the 3 atoms of oxygen, forming a mole- cule of water, (H2O.) The 2 atoms of chlorine set free, unite with the 2 atoms of Xa forming 2 mole- cules of common salt, (2 NaCl,) and the remaining group, CO2 escapes as a molecule of carbonic acid gas. Heat alone is oftentimes a most important factor in causing chemical decomposition and re- composition. If a salt known as ammonium ni- trate be placed in a flask and heated sufficiently, an interchange of the atoms of the constituent ele- ments will take place, according to the following equation :

NII4XO3 + Heat = 2H2O + :N'20

Ammonium Hydrogen Nitrous

Nitrate. Monoxide. Oxide.

It will be noticed by referring to the compounds in the preceding equations, that their names sug- gest their composition. When a compound mole- cule is composed of only two elements its chemical name always ends in ide^ as, hydrogen chloridCy

84 Inorganic Chemistry.

meaning, evidently, a combination of H and CI, (IICl ;) hydrogen monoxide, of H and 0, (HgO;) sodium c\\\oYide, of ^a and CI, (NaCl ;) Yiiirous oxide, of ]^ and 0, (Ng^O The most highly elec- tro-positive element in the formulae (a question to be studied later), is generally placed first, a rule, however, sometimes departed from, in order to better explain the relations between the elements in the group. In ammonium nitrate, the H, al- though electro-positive, follows negative ^, thus, NH4NO3, because we can better realize the relation that really exists between the two radicals NH^ and isTOg, which form the molecule in question.

By referring to the few preceding formulae we preceive the rule is observed, H is electro-positive to CI ; Na to C and 0 ; ISTa to CI ; H to 0 ; and C to 0.

In naming the compounds of inorganic chemis- try, we shall employ the full name of the positive element, preferring the noun to the adjective, as more euphonious. Where the compound is made up of elements which unite with each other in only one proportion, that is, form but one compound, the final syllables in the names of the electro-negative elements are changed into ide. H and CI unite with each other only in this proportion, H^Cl^^"^; hence the name of such compound is hydrogen chlo-

Notation and Nomenclature. 35

ride. K and I form but one compound, KI, its name is evidently potassium, iodide, etc. When two elements unite with each other in iiiore than one proportion, the distinctions are made by employ- ing the Greek numerals, mon, di, iri, etc., to indi- cate the number of atoms or radicles in the mole- cule. H and 0 form two compounds, H2O and II2O2 ; the first formula ma}' be called hydrogen monoxide, the second hydrogen dioxide, signifying one atom of oxygen and two atoms of oxygen re- spectively. The binary compounds of IS' and O furnish perhaps the best . example of these disr tinctions;

N^O N2O2 N2O3 N^O, N2O5

Nitrogen Nitrogen Nitrogen Nitrogen Nitrogen

Monoxide. Dioxide. Trioxide. Tetroxide. Pentoxide.

The name alone, therefore, indicates the number of O atoms in each molecule ; and they are all equally (imitrogen oxides.

There are also different terminations in the name of the positive element, to indicate the least or greatest relative proportion of the negative ele- ment in the series. In these nitrogen oxides, for instance, the lowest or mon (one) oxide is most fre- quently called wiivous oxide, and the highest, or pent (five) oxide is known as wiiric oxide. The prefix hyper (reduced sometimes to per) meaning above, is found coiivea(eiil':tc/^pivly to the name of

• • • • • •

• • •

3^ Inorganic Cheynistry,

a compound containing more of tlie negative ele- ment than exists in a previously named compound of the same elements. Thus nitrogen dioxide might be named as hypermtrous oxide. The prefix hjpoy meaning under, might, on tlie same principle, be applied to nitrogen tetroxide, and the latter named hypomtric oxide. These rules apply to any series of compounds made up of the same two elements.

etc '•t *- c C { c c

Notation and Nomenclature. 37

CHAPTER VII.

NOMENCLATURE.

The names of compounds more complicated in the number of their elements than those men- tioned in the preceding chapter, are, in inorganic chemistry, derived mainly, from their composition. Let it be understood that all acids contain H. Nitric acid, as its name implies, contains IST. If there be at least three elements in the molecules of acids, a fact which usually obtains, we are safe in assuming that 0 is the other element, unless the name of the acid is otherwise distinguished. We have, therefore, in the above acid, H and IST and O. It remains only to correctly formulate the number of atoms of each, to the molecule, and we accept the proof of analysis and the process known as equivalent substitution for this fact. The formula of nitnc acid is thus ascertained to be HNO3.

Then, there is another oxy-acid of nitrogen ; it is named mtvoiis acid — IINO2 — because it contains less negative 0 than nitric acid.

The names of the other acids are derived in the same way. Sulph,unV.P;Cid, is formulated II2SO4; sulphuroi^s acid, :|J.jS0;]V. /^^'^.If^^^v acid, HCIO3 ;

38 Inorganic Chemistry.

chloro?^5 acid, HCIO2 ; and A]/j90-chlorous acid, HCIO, etc.

Acids are classed as electro-negative, in contra- distinction to a class of compounds called bases. The latter are electro-positive, and many of them are also known as alkalies ; they are the opposite of acids.

These two classes have a strong love for each other, and combine to form another class of com- pounds, which have received the general name of salts.

Our conception of chemical salts, may be confined for the present, to the simple statement that they are, usually solid, neutral substances, produced by the union of acids with alkalies (or bases), and named accordingly.

If nitric acid be brought in contact with the al- kali— or base — sodium oxide, neutral bodies will result, as will be seen by the following equation :

I^aO + HXO3 = H2O -f :N'a^"03

Sodium Nitric Water. Sodium

Oxide. Acid. Nitrate.

The origin of the names of the first three com- pounds has already been explained ; the last sub- stance, it will be noticed, receives its name by applying the full name of the basic sodium, and changing the final ic in the name of the acid to ate. The name derived t'^^sy. ,is; sodium mivate. All

Notation and Nomenclature. 39

salts of nitric acid are nitrates. Salts of nitro?<5 acid are named nitrites. In the same way, all salts produced by the union of sulphuric acid with a base are named sulphates. Sulphurous acid produces salts called sulphi7c5, etc. The names of all salts whose acids contain more than two elements to the molecule, such as H^Og, terminate in either ate or ite; w^hile the names of salts derived from acids whose molecules contain only two elements, end in ide. For instance, hydrochloric acid — HCl — bi- nary, because made up of only two elements, acting on the basic metal sodium, IN'a, produces a binary salt whose name should end in ide^ as will be seen by the following reaction :

:N'a + HCl == H + KaCl

Sodium. Hydro-chloric Hydrogen. Sodium

Acid. Chloride.

In brief, inorganic salts, whose molecules contain three or more elements, have names which end in either ate or ite, and salts containing but two elements have names ending in ide. The reaction between an acid and a metallic base, usually consists in the metal taking the place of the H in the molecule of acid, thus :

f 2H

Hydrogen.

Zn	+	II^SO, =	= ZnSO^
Zinc.		Sulphuric	Zinc.
		Acid.	Sulphate

When the oxide of the metal is employed, then, in-

• • •

40

Inorganic Chemistry.

stead of the II escaping free as a gas, it will unite with the 0 of the base to form water.

ZnO + H2SO4 = ZnSO^ + H^O

Zinc Sulphuric Zinc Water,

Oxide. Acid, Sulphate.

Chemical compounds are definite in their nature, constant in the ratio of their elements. They fur- nish no evidence, in physical or chemical proper- ties, of their composition, except by analysis. I^ot so with mere mixtures, water and alcohol may be mixed in any proportion, the mixture exhibiting properties intermediate between those of its con- stituents, showing regular gradation according to the relative amount of water and alcohol that may be mixed together. A mass of pure water is a chemical compound, it is rendered appreciable by our senses, by the union of a great number of molecules of like construction ; that is, they are formed by the same kind and number of atoms ; two atoms of H, and one atom of 0,=Il20; and inasmuch as the individual atom has its own fixed and unchangeable weight, it follows that the mass of matter, made up of homogeneous molecules, each having the same kind and number of atoms, must be definite in its nature and constant in the ratio of its elements.

When two or more compounds are made up of the same elements then. ^? ^'^^ Ucn4 imperceptibly into each

Notation and Nomenclature. 41

other ^ as in the case of mixtures. Even though their molecules may differ in constitution, by only one atom of the same element, their chemical nature is divided by a sharp line of demarcation; they are separated, as it were, by an impassable gulf; and the compounds themselves show no properties that would leave us to suspect the presence of their constituent elements. Their composition is ascertained by analysis, and proven by synthesis. Carbon-monoxide, CO, and car- bon-dioxide, CO2, differ only by one atom of O, and yet they are not at all alike, chemically. The first is lighter than air, it is highly combustible, and is not absorbed by a solution of potash. The second is heavier than air, it is not a combustible, and is readily absorbed by a solution of potash, and neither indicates, in the slightest degree, that it is really a compound of C and 0. One more ex- ample of, perhaps, more familiar substances, may better explain the foregoing statement. Mercury and chlorine form two compounds; mercuric chlo- ride (HgCl2), is soluble in water; it is a strong corrosive poison, one centigram (1-6 grain) might prove a dangerous dose to an adult. Mercurous chloride (IIg2Cl2) is not soluble in water; it is a comparatively mild medicine, one hundred centi- grams (15 grains) Jiii^K^^ fl^b t'a,k^'>l'"\yithout danger.

?•.

• ••••••••«. » ».' ' > '•,

••• ••• ••••• * .» ' ' ' ' > , , , • I

'.* ''• ;.. '...',,/'>' ' .

• .•- ••. ,•, • .

• ••»

• • , •» »

• • *

• • *

42 Inorganic Chemistry.

They are commonly named, corrosive sublimate and calomel, respectively. Their molecules differ, as you perceive, by only one atom of Hg, and they exhibit no properties by which we could suppose that mercury and chlorine are the elements in their composition.

We shall consider other important facts in chemi- cal philosophy after we become acquainted with t'he principal non-metallic or electro-negative ele- ments. These, as a class, are more important, from a chemical standpoint, than are the metallic ele- ments, inasumuch as one at least, of the former, is a necessary constituent of all chemical compounds. Theirintroduction, together with the leading com- pounds which they form with each other, will be in the order best adapted, we think, to promote an intimate and pleasant acquaintance with them.

Oxygen. 43

CHAPTER VIII.

OXYGEN.

Symbol, 0. At. wt. IB. Sp. gr. 1.1056.

Oxygen is a colorless, tasteless, and odorless gas. It is the most abundant of the elements. It exists free in the atmosphere, of which it forms about one-fifth part, and of which it. is the active ele- ment. Combined with other elements, it consti- tutes about one-half the weight of the solid crust of the earth, and eight- ninths of the weight of water. It is also found as an important element of animal and vegetable tissues.

Oxygen was discovered by Priestly and Scheele in 1774, independently of each other. It can be obtained from any of its compounds, but only those which can give it up cheaply and in large volume are the ones employed for such purposes.

The favorite method is to heat the salt, potas- sium chlorate, in a retort, and collect the escaping gas over water. We do not regard a detailed de- scription of experiments necessary here, inasmuch as they are fully explained by the teacher.

KCIO3 + Heat = KCl -f 30

Potassium Potassium Oxygen.

Chlorate. Chloride.

44 Inorganic Chemistry.

All the 0 in the salt is thus driven off by the heat, leaving a residue in the retort composed of K and CI. If three-fourths, by weight, of potas- sium chlorate be mixed with one-fourth of an oxide, such as ferric oxide, cupric oxide, -or better, manganese dioxide (MnOg), decomposition will re- sult at a lower temperature, although either of the latter substances does not itself suffer decomposi- tion. Its influence is said to be due to catalytic action (?); a question not fully understood.

Oxygen combines, either directly or indirectly, with all the other elements, except fluorine, to form binary compounds; (i. e., H2O, CaO, AU2O3, etc.).

When a stngle element unites with O, it is said to be oxidized, and the process is called oxidation.

Oxidation, like other chemical action, always de- velops heat. When heat and light are both devel- oped by the process, the body is said to burn. The process of combustion will be sufiiciently described in connection with the element carbon. Ordina- rily, when a body burns, its elements are simply uniting rapidly with the O of the air. Bodies which burn in the air do so with much greater energy in oxygen alone. If pieces of burning charcoal or sulphur, or phosphorus, be placed in a jar of oxygen, the immediate rapid increase in the amount of heat and light is remarkable. If a

Oxygen. 45

candle with a glowing wick be plunged into a ves- sel full of oxygen, the candle will at once burst into a flame. Certain substances, which do not ordina- rily burn in the air, will do so readily in oxygen. A thin piece of iron or steel, such as the rubber saw of the dental labratory or a broken watch- spring, its surface previously brightened by sand paper, and having attached to the lower end a bit of burning match, or spunk, or sulphur, placed thus in a jar of pure oxygen^ will become ignited, and evolve exceedingly brilliant corruscations of heat and light.

The oxygen of the air, although weakened by its mixture with nitrogen and other gases, is the sup- porter of ordinary combustion. It is also the sup- porter of animal respiration; we inhale it with every breath, and alternately exhale the products which are formed by it in the body and which are carried, by the venous circulation, to the lungs, to be expelled.

The name oxygen, from tw^o Greek words, meaning a generator of acids, was given it by La- voisier, in 1778, who was the first to describe the important part which oxygen plays in the field of natural phenomena.

It is a necessary element in the formation of nearly all acids. If we examine with litmus test

46 Inorganic Chemistry.

paper, the jars in which were burned the sulphur or phosphorus, we will detect an acid reaction : not sa the contents of the jar in which the iron burned; the latter fact indicating that all oxides are not of an acid nature. It is only some of the oxides of the non-metallic elements, or those of the metallic elements bordering on the non-metal- lic, which are classed as acid.

These oxides of the more highly electro-positive of the metals, such as barium, potassium, etc., are always basic or the opposite of acid. Barium oxide and sulphuric oxide will combine directly under the influence of heat, and thus form the salt known as barium sulphate.

BaO + SO3 = BaSO^

Barium Sulphuric Barium

Oxide. Oxide. Sulphate.

The acid oxides unite with water to form acids,

as:

SO3 + H2O = H2SO4

Sulphuric Water. Sulphuric

Oxide. Acid.

Basic oxides react with acids to form correspond- ing salts, as :

CaO + H2SO4 == CaSO^ + H2O

Calcium Sulphuric Calcium Water.

Oxide. Acid. Sulphate.

There is a third class of oxides called neutral^ of which water is a good example. They are neither acid nor basic, but some of them may act in either

Oxygen. 47

capacity, according to circumstances. When cal- cium oxide, which is strongly basic, is mixed with water, the latter acts as an acid oxide, resulting in the production of the salt caled calcium hydrate, or hydroxide.

CaO + H2O = Ca(H0)2

Calcium Water. Calcium Hydrate,

Oxide.

It will be seen, on the contrary, by referring to the proper equation preceding, that water acting on SO 3 takes the part of a basic oxide, in forming the molecule of sulphuric acid, or hydrogen-sul- phate (H2SO4).

Ozone. — When an element is capable of existing in more than one state it is called allotropic. Oxy- gen is an allotropic element. It exists in a passive and in an active state. Passive oxygen is the kind we have been studying. Active oxygen is named ozone. The latter substance is far more energetic as an oxidizing agent than ordinary oxygen. It is the great natural disinfectant, destroying by oxi- dation the infectious matter that appertains to the metamorphosis of animal and vegetable tissues. Ozone is developed in a variety of ways :

Ist. By heat; as when platinum wire is merely heated in the air.

2nd. By light; as when CO2 is decomposed by living plants, by the aid of sunlight ; and when

48 Inorganic Chemistry.

essential oils are exposed to sunlight and summer temperature.

3d. By electricity; as when the silent electric discharge takes place in the air, or in oxygen gas, and by electrolysis of water.

4th. By slow oxidation ; as when a clean stick of phosphorus is partially exposed to the air, or when a strongly heated glass rod is placed in va- por of common ether.

5th. By rapid combustion; as when a vigorous blast of air forces the top of a Bunsen flame into a large beaker, the contents of the beaker will give the ozone reaction.

A good test for the presence of ozone is paper moistened with dilute solution of potassium iodide (KI) and starch. The ozone, by uniting with the potassium, sets the iodine free, which turns the starch to a deep blue color.

Ozone is an irritating poison to animal tissues, if inhaled in quantity. Unlike ordinary oxygen, ozone has a decided odor, hence its name, which means to smell. It is one-half as heavy again as oxygen ; its density being 24, and that of the lat- ter 16. In fine, ozone is oxygen modified into a condition of intense activity. All its combina- tions with other individual elements produce only oxides.

Hydrogen. 49

CHAPTER IX.

HYDROGEN.

Symbol H. At. wt. 1. Sp. gr. 0.0693.

Hydrogen is a colorless gas, without taste or smell. It is the lightest body known, being about foui'teen and a half times lighter than air. The spectroscope shows that hydrogen is a constituent of the sun, the fixed stars and, largely of the celes- tial nebulae. It is found occluded in meteoric iron.

Hydrogen is found free in volcanic gases. Com- bined with oxygen, it forms the compound water ; hence its name, given it by Lavoisier, signifying '^ generator of water." It is an important element of animal and vegetable tissues, and of mineral oils.

Hydrogen was known in the sixteenth century,

but was first accurately described by Cavendish in

1766. It can be obtained from its compounds by

various methods, but is usually prepared by action

of zinc, on dilute sulphuric acid, or hydro-chloric

acid.

Zn -t- 2IIC1 = ZnCl2 -h 2H

Zinc. ir.Vflrochloric Zinc; Hydrogen.

Acid. Chloride.

The gas may be collected over water or by dis- 5

50 Inorganic Chemistry,

placement of air. Although hydrogen is the lightest substance known, it is undoubtedly the vapor of a highly volatile metal. We describe it thus early, in connection with the non-metals, be- cause of the wonderfully important place it holds in the family of elements. On account of the high diffusive power and combustibility of hydrogen, great precaution should be observed in experi- menting with the gas, in order to avoid the danger of explosion. Heated to a temperature of about 500°C. (982°F.), it unites with oxygen : the union of these gases developing the highest temperature produced by chemical action. One gram of hydro- gen in oxidizing, or burning, will raise the tempe- rature of 34,462 grams of water from 0° to 1° ; that is equal to 34,472 heat units. The compound which it forms by direct union with oxygen is water (H2O), the molecule of which contains two parts by weight, or two atoms of hydrogen, and sixteen parts by weight, or one atom of oxygen. The mol- ecular weight of any substance is the sum of the atomic weights^ and inasmuch as the two atoms of hydrogen weigh two, and the one atom of oxygen weighs sixteen, the molecular weight of water must be 2 + 16 = 18.

Water is the most abundant of chemical com- pounds. Notwithstanding its neutral nature, being

Hydrogen. 51

neither acid nor alkali, it is a very active substance, clieniically. It leads all other liquids as a solvent. With but few exceptions, solids will dissolve more easily in warm than in cold water, while certain gases, as 0, N2O, CO2, etc., are more soluble in cold water than in warm.

Pure water is tasteless, ordorless, and, when in small quantity, colorless. It exists in certain com- pounds as w^ater of crystallization, enabling them to assume a definite crystalline form, as, natural gyp- sum, blue-stone, etc. When sufficiently heated, this water is driven out, and the substance loses its crystalline form, but will take up water again most readily, as in the case of plaster of parfs.

Oxygen and hydrogen may be induced to unite in the proportion of two atoms of each, to form hydrogen dioxide (H2O2), commonly called perox- ide of hydrogen. It may be prepared by acting on barium dioxide, held in suspension in water, by either of several acids, as :

Ba02	+	Ha CO J =	=: BaCOg	+	H.O^
Bftrium		Carbonic	Barium		Hydrf)gen
Dioxide.		Acid,	Carbonate.		Dioxide.

Approximately pure, peroxide of hydrogen is colorless; it possesses, however, an ozone-like odor and a peculiar metallic taste. It is never used in medicine, or the arts, in the undiluted form, but is usually held in solution in glycerine or water. A

52 Inorganic Chemistry.

"ten volume " preparation of it will give off ten times its o^yn volume of free oxygen. The tem- perature of summer heat will cause the molecule (H2O2) to decompose, one of the O atoms escap- ing. The solution should, therefore, be kept in a cool place, except when in use.

It is an excellent germicide and disinfectant, de- stroying the infectious matter by the activity of the nascent oxygen which it supplies.

An element is nascent at the time it is set free from combination, and is then more anxious to unite with other bodies than when it is in its ordi- nary state.

A trace of acid (sulphuric or phosphoric) is us- ually found with the peroxide of hydrogen solu- tion, to render the preparation more stable ; and- the results of experiments with the peroxide on pus, bone, etc., are often misjudged on account of the acid present.

Chlorine. 53

CHAPTER X.

CHLORINE.

Symbol, CI. At. wt. 35.5. Sp. gr. 2.46.

Chlorine was discovered by Scheele, in 1774. Its elementary character was proven by Dav}^ in 1810, who gave it the name it bears, w^hich signifies its color, ^' greenish yellow^

Chlorine is not found free in nature. It exists abundantly, however, in combination with Na., Ca., K., and Mg., in sea water, and saline springs. Vast deposits of solid sodium chloride, or common salt, are found and mined; it being a necessary article of every day use.

Chlorine is usually obtained in quantity by gently heating together certain proportions, indicated by their molecular weights, of the two first following compounds :

iMn02 I 4IIC1 =^ 2II2O + MnCl2 + 2CI2

Manganese Hydrochloric Water Manganese Chlorine

Dioxide. Acid. Chloride.

It may also be obtained, sufficiently pure for ordinary experiment, by acting on common bleach- ing powder with dilute sulphuric acid. The re- action of these substances, being rather complica- ted, will not be considered at this time.

54 Inorganic Chemistry.

Chlorine is a greenish-yellow gas, of an intoler- able suffocating odor and astringent taste. When subjected to a cold of 40°, or at a common temper- ature, to a pressure of four atmospheres — 60 pounds to the square inch, it condenses to a yellow liquid of sp. gr. 1.38.

Water will dissolve nearly three times its own bulk of chlorine, the solution acquiring the color and odor of the gas; it is known as aqua Mori, and is employed to advantage in practice, as a dis- infectant, and to bleach discolored teeth. Aqua chlori, exposed to the influence of light, decom- poses according to the following equation :

H2O, 2C1 = 2HC1 f O

Water. Chlorine. Hydrochloric Oxygen.

Acid.

It must, therefore, be preserved in a dark place. Chlorine acts indirectly as a bleaching agent and disinfectant through its love for the hydrogen of water, letting the 0 go free, vide the above equa- tion, which latter element, in its nascent state, at- tacks the coloring matter, or infectious matter, as the case may be, forming with either, new com- pounds that are destitute of color, or free from the germs of disease. Mineral colors, as a rule, are not affected by chlorine.

The affinities of chlorine are exerted mainly toward hydrogen and the metals. If a lighted

Chlorine. 55

candle, the combustible elements of which are C and H^ be placed in a jar tilled with chlorine, dense volumes of smoke will be evolved, owing to the chlorine taking up with the H of the candle, resulting in HCl, and the rejection of the C, which escapes as smoke. A piece of tissue paper moist- ened with warm oil of turpentine, and thrust into a jar of chlorine, shows the same phenomenon. Finely divided arsenic, or antimony, or thin leaves of copper or bronze, or a bit of phosphorus, at ordinary temperatures, and sodium, at a higher temperature, will burn in chlorine, forming a chlo- ride in each case. A mixture of hydrogen and chlorine, exposed to the sunlight, will unite with explosive violence. In tine, chlorine unites, either directly or indirectly, with all the elements, form- ing a chloride with each, some of which, however, are very unstable compounds.

Hydrogen Chloride. — Chlorine and hydrogen unite with each other in but one proportion. The compound is generally called hydrochloric acid. It is a colorless gas, of a pungent odor, is irrespi- rable, though not so irritating as chlorine, and is noncombustiblc. Its specific gravity is 1.264, its density (II as unity) is 18.25. Subjected to cold and pressure, it condenses to a colorless liquid, of specific gravity 1.27.

56 Inorganic Chemistry.

Hydrochloric acid is manufactured on a large scale by heating togetlier quantities of common salt (;N"aCl) and strong sulphuric acid, as indicated by the following equation :

2:N'aCl + H2SO4 = :^a2S04 + 21101

Sodium Sulphuric Sodium Hydrochloric

Chloride. Acid. Sulphate. Acid.

The gas (HCl) is very soluble in water. A given volume of wat'er will dissolve 450 volumes of the gas, and a more or less saturated aqueous solution becomes the hydrochloric or muriatic acid of com- merce, possessing the same acrid and acid proper- ties of the gas itself. The presence of the w^ater, however, is not expressed in the reactions of the acid, so that the formula HCl means either the gas alone, or its solution in water.

Hydrochloric acid is an important substance. It dissolves many of the metals, such as aluminum, tin, iron, zinc, etc., the reaction consisting in the metal supplanting the H of the acid, resulting in free hydrogen and metallic chlorides. As before alluded to, as a rule, wnth some exceptions, when- ever any acid attacks a metal, a quantity of H equivalent to the metal escapes free, the metal uniting with the residue of the acid to form a salt of the metal in question, as :

2HC1 + Fe = 2H + FeCl2

Hydrochloric Iron. Ferrous

Acid. Chloride.

Chlorine. 57

Hydrochloric acid is therefore the type of all chlorides.

It is one of the solvents in the gastric juice, and is probably developed there by the influence of a special ferment^ which, in some way not yet under- stood, induces the CI of the sodium chloride, one of the proximate principles of the body, to unite with the H of the water present, or some other hydrogen compound, or vice versa. The child of the union would, of course, be HCl.

Dr. George Watt, of Ohio, the recognized origi- nator of the chemical (per se) theory of dental de- cay, proposes hydrochloric acid as the active cause of the brown, or common variety of decay of teeth.

The structure of a tooth is generally divided into animal (matrix) and mineral portions ; the latter consisting mainly of calcium phosphate and cal- cium carbonate.

If hydrochloric acid is formed in the mouth, in accordance with the afflnities by which it is devel- oped in the gastric juice, a chemical analogy by no means improbable, the nascent individual mole- cules of the acid would simultaneously decompose the calcium carbonate, and dissolve the calcium phosphate.

CaC03	+	2IIC1 —	CaCL,
Calcium Carbonate.		Hydrogen Chloride.	Calcium Chloride

58 Inorganic Chemistry.

The calcium phosphate of the tooth, although riot entering into the equation, loses its structural integrity by solution, and the animal portion more or less remains in situ.

There are compounds of chlorine, hydrogen, and oxygen, the elements we have especially introduced thus far, which are worthy of some consideration at this time. They are all acid in their nature, and may be regarded as oxides of HCl : HCIO4, Perchloric acid. HCIO3, Chloric acid. HCIO2, Chlorous acid. HCIO, Hypochlorous acid.

The salts of these acids are known, seriatim, as perchlorates, chlorates, chlorites, and hypochlo- rites. The first and third class are of no special interest, but the chlorates and hypochlorites are used largely as important agents in chemistry and materia medica ; they will be considered later on in connection with certain metals. There are three oxides of chlorine, CI2O, CI2O2, CI2O4, which are highly explosive, but possess no other interrst.

Chlorine is the principal member of a group of elements which contains also iodine, bromine, flu- orine. They are all called halogen elements, because the sea is the principal source of chlorine, iodine,

Chlorine. 59

and bromine ; so great is the resemblance to each other, in their chemical nature, that a description of one, as, for instance, chlorine, will serve in a measure for that of the others.

60 Inorganic Chemistry.

CHAPTER XI.

IODINE.

Symbol, I. At. wt. 127. Sp. gr. 4.95.

Iodine is obtained from the ash of sea weeds. It is a dark bluish solid, consisting of rhombic scales, of a metallic luster. It melts at 107° (225° F.), and boils at 180° (356°F.), evolving a magnifi- cent violet vapor, of specific gravity 8.72.

Iodine requires 7,000 parts of water to dissolve it. It is freely soluble in -an aqueous solution of its most important compound, potassium iodide, and in alcohol, ether, chloroform, and carbon di- sulphide. It is not as active, chemically, as chlor- ine, though it combines directly with most of the metals forming iodides. It strikes, with a solution of starch, a deep blue color, so intense that one part of iodine in 300,000 of water can be detected by the starch test.

Iodine, both free and in combination, is a valu- able therapeutic agent,* as a resolvent and anti- septic; it is also largely used in photography.

*Brief allusion to medicinal qualities, while considering the non-metallic elements, is excusable, as we hope to deal justly by their compounds in materia medica.

Bromine. 61

BROMINE.

Symbol, Br. At. wt. 80. Sp. gr. 3.187.

Bromine is prepared from sea water and saline springs. It is a red-brown liquid of disagreeable odor, hence its name. Heated to a temperature of 63° (145°F.), it boils, yielding a deep red vapor, of specific gravity 5.5. Cooled to —22° (— 8°F.), it becomes a crystalline lead-gray solid. One part of bromine requires 33 parts of water to dissolve it. It is a corrosive poison ; exerts a strong bleaching power. It is, chemically, less active than chlorine, but more so than iodine. Some of the metals will burn in its vapor, producing bromides. It is used extensively in photography, and some of its com- pounds are of therapeutic value.

FLUORINE.

Symbol, F. At. wt. 19. Sp. gr. .

Fluorine is a constituent of a substance known as fluor spar, meaning, I flow, because this com- pound— CaF2 — is used as a flux in the reduction of some metals.

Free fluorine (but recently isolated) is a colorless gas, of pungent odor, and exceedingly corrosive.

62 Inorganic Chemistry.

It is especially distinguished as the only element which refuses to unite with oxygen ; and although in its free, and therefore inactive state, it shows only slight affinity toward silicon, the latter ele- ment is violently attacked by nascent fluorine, which is developed by bringing together hydro- fluoric acid and a silicon compound, such as glass. Hydrofluoric acid, HF, is usually prepared by re- action of calcium fluoride and sulphuric acid, in a vessel of platinum or lead.

CaF2 4- H2SO4 = CaSo4 + 2HF

Calcium Sulphuric Calcium Hydrofluoric

Fluoride. Acid. Sulphate. Acid.

This acid, when pure, is a colorless gas, but in its ordinary condition it is dissolved in water. It is of peculiar interest, because it is the only sub- stance that freely attacks such compounds of sili- con as glass, and porcelain teeth. It is useful in the arts, for etching on glass.

HALOGEN ACIDS.

The analogy between the halogen elements, chlorine, iodine, bromine, and fluorine, is best ex- emplified by their binary hydrogen compounds :

Hydrochloric acid HCl

Hydriodic acid HI

Hydrobromic acid HBr

Hydrofluoric acid HF

Halogen, 63

The first and last of these acids have already been sufficiently described. The second (HI) and third (HBr) are also pungent, colorless gases, yqyj soluble in water, and are used in practice in aque- ous solution. They are the prototypes of all iodides and bromides, as hydrochloric and hydro- fluoric acids are the types respectively of chlorides and fluorides. There are also oxy acids of iodine and bromine analogous to those of CI. The prin- cipal ones have the formula of HIO3 and HBrOg, corresponding to chloric acid HCIO3. Their salts are called iodates and bromates.

64 Liorganic Chemistry.

CHAPTER Xir. NITROGEN.

Symbol, K At. wt. 14. Sp. gr. 0.971.

Nitrogen is a colorless, odorless, and tasteless gas. It was discovered by Rutherford in 1772, and received its name because it was found to be a necessary constituent of niter.

Nitrogen and oxygen are the principal compo- nents of the atmosphere; four-iifths of nitrogen, and one-fifth of oxygen. Although not chemically combined, their intimate mixture in the above proportions obtains throughout, the nitrogen serv- ing to retard within reasonable bounds the energy of oxygen.

If a piece of phosphorus be. burned in a given volume of air, confined over water, the phosphorus takes up all the oxygen, the water rapidly absorbs the compound so formed, and the nitrogen remains alone, comparatively pure.

Nitrogen is not a supporter of combustion, nor of respiration; it is, in fine, remarkably inert, showing little disposition to unite directly with other elements, although its compounds are nu- merous, and some of them of exceeding energy.

Nitrogen. 6^5

Besides its existence in the atmosphere, it is found \\\ nature in the compounds known as nitrates, and in ammonia, and is also an essential element of certain animal and vegetable substances.

Ammonia. — Ammonia is a gaseous compound of nitrogen and hydrogen (NHg). It is formed slowly at common temperatures, by putrefactive decom- position of animal and vegetable substances con- taining nitrogen; more rapidly when clippings of horns, hoofs, or hides, or other animal tissue, are subjected to heat — hence the name sometimes given it of "spirits of hartshorn." Many of its compounds are now obtained by the destructive distillation of coal, in the manufacture of illumin- ating gas. Ammonia itself is prepared by gently heating together a salt known as " sal ammoniac," or ammonium chloride, and calcium oxide (quick- lime). (NH4CM)2 + CaO = CaCl^ 'H2O + 2NH3

Am. chloride. Calcium Calcium Water. Ammonia.

Oxide. Chloride.

Ammonia is a colorless gas, of specific gravity 0.59. It is possessed of a peculiar pungent odor, by which its presence may be detected. Subjected to a pressure of a hundred pounds to the square inch, at 10° (50°F.), it condenses to a clear liquid, of specific gravity 0.76. The liquid ammonia is highly volatile, and in passing into the gaseous 6

66

Inorganic Chemistry.

state, by removal of pressure, it absorbs a large amount of heat. It is for this reason, as well as its cheapness, that ammonia is employed in the artificial production of ice.

Ammonia gas is exceedingly soluble in water ; one volume of water at 15° (59°F.) will dissolve 783 volumes of the gas. This solution, further di- luted, is the well known '' aqua ammonia" of com- merce. It evolves the gas again upon iieating, or on exposure to the air. It is a stimulant when slightly inhaled, and is often so employed in non- complicated syncope.

Ammonia, whether in the gaseous form or in the aqueous solution, is strongly alkaline; it unites with and neutralizes the strongest acids, forming with them compounds, called salts of ammonia. The hydrogen of the acid, in such combination, is not driven out, but seems to take up intimately with the ammonia itself, apparently producing, in the reaction, an unsatisfied group (I^H4), which has received the name of ammomum., because it acts in many cases like an atom of some of the metals. Thus:

OTI3 + IICl = (:N'H4)C1,

Ammonia. Hydrochloric Ammonium

Acid, Chloride.

analogous to sodium chloride, IRaCl. Ammonium chloride was first prepared by the Arabs of the

Nitrogen, 67

Libyan deserts, as a substitute for common salt, by heating camel's dung. They named it '' sal am- moniac"— salt of Ammon — in honor of Jupiter Ammon, whom they worshiped, and from w^hich the name ammonia is derived. Ammonium iodide and ammonium bromide are analogous salts.

Nitrogen and oxygen unite wnth each other in five proportions. Their compounds have the following names iind formulas:

Nitrogen pentoxide (or miric oxide) ^2^5

Nitrogen tetroxide ^2^4

Nitrogen trioxide ^2^3

Nitrogen dioxide ^2^2

Nitrogen monoxide (or mXvous oxide).... N2O The first and third are acid oxides; they will combine with water to form acids. Nitric oxide, sometimes called nitric anhydride, may be prepared by action of chlorine on solution of silver nitrate: 2AgN03 + 2C1 = 2AgCl + 0 + l^^O,

ArKeutura Chlorine. Argentum Oxygen. Nitric

Nitrate. Chloride. Oxide.

Nitric oxide is a colorless crystalline solid, of unstable, explosive qualities. It reacts energetic- ally with water, producing nitric acid : N2O5 + [1,0 = 2IINO3

Nitric oxide. .V>»ter. Nitric acid.

Nitric acid was known to Geber in the eighth century, and described by Raymond Lully in 1225. Cavendish, in 1785, first determined its true compo-

68 Inorganic Chemistry.

sition. It is formed in nature in various ways ; by strong electric currents passing through air; by ozone acting upon the nitrogen, or the ammonia in the air, or on nitrogen dioxide, trioxide, and tetrox- ide, in the presence of water.

When animal or vegetable matters containing nitrogen decompose, ammonia is produced, and this compound, in presence of weak alkaline bases, is decomposed by nascent oxygen, or by ^ ozone, into water and nitric acid :

NH3 + 04 = H2O + HNO3

Ammonia. Water. Nitric acid.

A process of manufacture, following these lines, will result in the development of artificial beds of niter.

In the arts, however, nitric acid is always pro- duced by "heating sulphuric acid with either potas- sium nitrate or sodium nitrate.

An equation will best explain the reaction :

KN03	+	H,SO, =	= HKSO4 +	HNO3
Potassium		Sulphuric	Hydropotassium	Nitric
Nitrate.		Acid.	Sulphate.	Acid.

Nitric acid, commercially known as aqua fortis, when pure, is a fuming, colorless, corrosive liquid, having a specific gravity of 1.52 ; chemically, it is an exceedingly energetic body, attacking most of the metals, and forming with them salts called nitrates, nearly all of which are soluble in water.

Nitrogen. 69

xTitrogenous animal substances, as wool, silk, and parchment, are colored a deep yellow by it. And many non-nitrogenous substances, as cotton, sugar, and glycerine, are converted into explosive bodies by- nitric acid.

By virtue of its oxidizing power, many remark- able reactions are induced to take place. Gold is not affected by any single acid, except slightly by selenic acid, but if the two acids, hydrochloric and nitric, be mixed and gently heated, the nitric acid will give up enough oxygen to oxidize all the hydrogen of both acids, setting the chlorine free, which latter element, in its nascent state, readily unites with the gold present, forming the soluble AUCI3.

9HC1 + 3HXO3 = 6H2O + 3N0C1 + 2CI3.

2Au ^ 2CI3 = 2AUCI3.

The XOCl is of no importance, some authorities claiming that the residue of nitrogen and oxygen remain together as 3N0, letting all the -chlorine escape to the gold.

Nitric acid is believed by many experimenters to be the cause of the rapid, or white, variety of decay of teeth. This idea does not conflict in the least with the so called "germ theory" of decay, inasmuch as the ferment of nitric acid has been discovered re- cently. The manner of its formation in the re-

70 Inorganic Chemistry.

cesses of the teeth, as described by Dr. Watt, is owing to the decomposition of nitrogenous sub- stances (putrefaction), developing simultaneously ammonia and nascent oxygen, which immediately react on each other, resulting in the oxidation of the hydrogen and nitrogen into nitric acid. The action of any acid on the tooth, in forming caries, must occur at the place, and at the instant, of its development ; that is, molecularly. It is not con- ceived that caries are formed only by a general acid nature of the oral fluid ; on the contrary, the latter may remain neutral, or be even decidedl}^ alkaline. The favorite trysting place of the fer- ments, in dental caries, is usually a quiet nook, unfrequented by the brush, wdiere the cultures consisting of organized debris, are changed into simpler bodies, and many of these, ultimately, into poisonous ptomaines and acids.

Little need be said of the dioxide, trioxide, and tetroxide of nitrogen. The dioxide (N2O2) is able to take up oxygen from the air and is thereby con- verted into the tetroxide, ^^2^4 5 ^^^^ latter sub- stance is a good oxidizing agent, as we shall learn by and by. The trioxide (IS'gOg) is the anhydrous oxide of nitrous acid, as the pentoxide (^2^5) ^^^ of 7iitric acid ; the salts of nitrous acid are called ni- trites, as those of nitric acid are called nitrates.

Nitrogen. 71

Nitrous Oxide. — Or nitrogen monoxide. Mole- cular formula, XgO. Sp. gr. 1.527.

Nitrous oxide was discovered by Priestly in 1776. Sir Humphry Davy, in 1807, described its exhilar- ating properties, and in 1845 Dr. Horace Wells, aii American dentist, of Hartford, Conn., employed it as an anaesthetic, and in so doing, became the orig- inal, genuine discover of ancesthesia.

Nitrous oxide is prepared by carefully heating in a retort the salt known as ammonium-nitrate. The retort is connected by means of glass and rub- ber tubing with a series of wash bottles, the tube ending in a receiver placed over water :

NH4NO3 -f Heat =z 2H2O + N2O

Am Nitrate Water. Nitrous

Oxide.

The wash bottles usually contain water, potas- sium hydrate, and ferrous sulphate; these sub- stances neutralize any traces of the higher oxides of nitrogen that may be evolved, and which other- wise would pass through with the nitrous oxide into the receiver.

Nitrous oxide is a colorless, odorless gas, with a slightly sweetish taste. Subjected to a pressure of 45 atmospheres at 0° (32°F.), it condenses to a clear, mobile liquid of specific gravity 0.9; this liquid freezes into a snowlike mass, by the effect of its own evaporation, when allowed to escape freely

72 Inorganic Chemistry.

into the air. Its boiling point is — 88°(— 126°F.) ; its freezing point is — 101°(— 150°F.).

The gas is quite soluble in alkaline solutions ; it is also soluble in water; more so in cold water than in warm ; 100 volumes at IS*' (60°F.) will dissolve 78 volumes of the gas. It possesses decided disin- fectant and antiseptic properties. Impure water, containing much organic matter, becomes pure and sweet, and remains so indefinitely, after dissolving even a small quantity of the gas.

Kitrous oxide is readil}^ decomposed by the heat of burning bodies, letting its oxygen go to support the combustion. In this way combustible bodies will burn in it, much like we saw them do in oxygen, with greater energy than in the air. In this way, also, it supports animal respiration to a certain point. One of the products it develops in the body (CO 2) can not escape, as in ordinary breath- ing; the unavoidable retention, therefore, of this product, in the central and other capillaries, in- duces more or less asphyxia, according to the quantity and rapidity of the inhalation of the un- mixed gas.*

Nitrous oxide is now largely supplied to the pro- fession, condensed to the liquid state in metallic cylinders.

* The possible chemico-physiological action of nitrous oxide will be considered with the compounds of iron.

Sulphur. 73

CHAPTER XIII.

SULPHUR.

Symbol, S. At. Wt. 32. Sp, gr. 2.04.

Sulpliur (brimstone) has been known from the earliest historic ages. It is found free in certain volcanic regions. It is found also in nature in combination with other elements, as iron, copper, mercury, zinc, lead, arsenic, antimony, and hydro- gen. The sulphides are important natural com- pounds, and with oxygen and certain metals, such as calcium, magnesium, barium, strontium, and sodium, it is found in the class of salts known as sulphates. Sulphur is an essential element of ani- mal bodies, and of many vegetables.

It is a yellow, brittle solid, freely soluble in car- bon disulphide, but not in water; it melts at 114°(237°F.), and boils at 448°(824°F.) ; it is taste- less and odorless, and is not a conductor of heat or electricity.

Sulphur is capable of crystallizing in two distinct forms; it is, therefore, said to be dimorphous. The natural crystals, and those deposited from solu- tion of the element in carbon disulphide, are rhom- bic octohedra, while melted sulpliur, if allowed to 7

74 Inorganic Chemistry,

cool slowly, will assume a prismatic form. An amorphous (non-crystalline) variety is obtained by pouring melted sulphur into cold water.

When heated in the air to 260°(500°F.), sulphur takes fire, and burns with a pale, lambent flame, forming SOg ; and certain metals, if heated in its vapor, will burn readily, forming sulphides. It, therefore, shows an aflinity for oxygen and various metals; it also unites directly with carbon.

Dental rubbers contain from 15 to 20 per cent of " flowers of sulphur," which enables the caoutchouc to become vulcanized into a hard material. Sul- phur has been suggested as a filling for root canals, being fused therein by heated instruments, and for setting crowns.

Sulphur unites with oxygen in two proportions. When sulphur is burned in the air, or in oxygen, the dioxide (SO2) is formed; this substance is a good disinfecting and bleaching agent, being a de- oxidizer, able to take away oxygen from certain deoxidizable bodies, which destroys their identity.

Sulphur dioxide is an acid oxide; united with water, sulphurous acid is the result :

SO2 + H2O = H2SO3

■ Sulphurous acid.

The salts of this acid are named sulphites.

The other oxide of sulphur is the trioxide (SO^)

Sulphur. 75

or sulphuric oxide. It is usually prepared by oxi- dizing sulphurous oxide — the dioxide SO2. Sul- phur trioxide is a white wax-like solid, of a silky, librous appearance, somewhat resembling asbestus. It unites with water, giving rise to great heat, pro- ducing sulphuric acid:

SO3 + H2O = H2SO4

Sulphuric Acid.

Sulphuric acid, hydrogen sulphate, next to water itself, is perhaps the most generally useful sub- stance in chemistry: it occurs free in the waters of certain springs and rivers, and in the saliva of cer- tain mollusks, and is the type of all sulphates.

The preparation of sulphuric acid — also known as oil of vitriol — involves several simple chemical reactions :

1st. The burning of sulphur in the air to obtain sulphurous oxide SOg.

2d. The presence of nitric acid (2H]Sr03) which supplies nitrogen tetroxide ^2^4-

3d. The latter compound gives oxygen to the SO2, changing it into SO3, and is itself reduced to nitrogen dioxide N2O2.

4th. Water, heated by the burning sulphur, unites with the SO3, producing sul[)liuric acid.

5th. The taking up of oxygen from the air by

76 Inorganic Chemistry.

the uitrogen dioxide, which thus serves as a carrier of oxygen.

The whole process may be more easily under- stood by referring to the following equations :

S H- 20 = SO2.

2SO2 + N2O4 r=r 2SO3 -h ^202- SO3 + H2O = H2SO4.

K2O2 -f 20 = N2O,.

Inasmuch as the process is continuous and si- multaneous, from the burning of the sulphur to the deposition of the acid on the floor of the leaden chamber, it is probable that other and complicated reactions take place. The above explanation, how- ever, is the one generally accepted as the simplest view that can be taken in the premises and is, at least approximately, correct.

Sulphuric acid is a colorless, oily liquid, of spe- citic gravity about 1.85. Freezes at — 26° (— 15°F.) and boils at 328° (622°F.). It has a strong aflanity for many of the metals. It is always thirsty for water, their union evolving great heat. It absorbs moisture from the air and from other gases, and is therefore often used as a drying agent. Its general action on organic matters is to dehydrate them, that is, to take from their substance the elements oxygen and hydrogen, and induce them to combine to form water, that its thirst may be satisfied.

Sulphur, 77

Sulphuric acid is more than likely involved in the condition known as " black decay " of teeth. Its production in situ is probably due to the energy of nascent oxygen on hydrogen sulphide (H2S), these being evolved from the organized debris in contact with the tooth, Orud which is said to un- dergo decomposition by the influence of some not yet detected special form of bacteria.

The phenomena of " black decay " really seem to be an arrest of the destructive proceedings of some active solvent, previously at work. Any well- marked specimen of this form of caries represents the surface of the cavity of a dark brown or black appearance, hard, and sometimes polished, and which is comparatively immune from further decay. The limiting action of sulphuric acid on tooth structure explains the above physical characteris- tics. Its molecules, at their birth, attack the earthy portion, forming insoluble calcium sulphate (CaSO^), and at the same time dehydrating the animal or gelatinous portion, which is mainly made up of carbon, hydrogen, and oxygen ; these two latter elements are withdrawn, as already alluded to, leaving the indestructible carbon as a residue, to be incorporated with the insoluble sulphate, producing thus a protecting covering to the unaf-

78 Inorganic Chemistry.

fected parts beneath against fnrther inroads both of the causing agent and other solvents.

A gaseous compound of sulphur and hydrogen (sulphuretted hydrogen, dihydrogen sulphide, sul- phydric acid, etc., U2S), is found in nature, and also largely employed in the labratory as an im- portant re-agent in classifying the metals, according as their sulphides are either soluble or insoluble in acid and alkaline solutions.

Quite a number of oxygen acids of sulphur are known as thionic acids; their molecules contain 2 atoms of H and 6 of 0, and 2, 3, 4, and 5 atoms of S, respectively. They are, however, of no general or special interest to us.

SELENIUM.

Symbol, Se. At. wt. 79. Sp. gr. 4.5.

Selenium, named in honor of the moon, belongs to the less abundant elements. It is occasionally found free, but generally in company with sulplwir, and in the selenides of silver, mercury, lead, and copper. It unites with hydrogen to form a gaseous compound (H2Se), analogous to sulphuretted hy- drogen, of an extremely nauseous odor. It forms acids corresponding to those of sulphur: selenious acid (HgSeOg), and selenic acid (H2Se04), the lat- ter being the only single acid that will even spar- ingly attack gold.

Tellurium. 79

TELLURIUM.

Symbol, Te. At. wt. 128. Sp. gr. 6.2.

Tellurium, named from tellus, the earth, is a rarer element than selenium. It occurs free in small quantities, and in the tellurides of mercury, silver, lead, bismuth, and gold. In Colorado, the tellurides of silver and gold are important ores. Physically, it resembles the metals, but in its chem- ical nature, it is closely related to sulphur and selenium.

The three elements form similar compounds — with hydrogen (Il2Te), and with oxygen (Te02Te O3), and corresponding acids (H2Te03, Il2Te04).

80 Inorganic Chemistry,

CHAPTER XIY.

PHOSPHORUS.

Symbol, P. At. wt. 31. Sp. gr. 183—214.

Phosphorus was discovered by Brandt in 1669. It does not occur free in nature, but exists in com- bination, generally as phosphates. It is a constit- uent of teeth, bones, and other tissues, and is obtained in our food, mainly from the seeds of plants.

Phosphorus is prepared from the ash of bones by treatment with sulphuric acid and charcoal. It is a yellow, waxy, translucent solid, easily cut with a knife, is luminous in the dark, by slow oxida- tion. At 50° (122°F.) it takes fire, and burns with great brilliancy. Its field of energy is very wide, as it combines with nearly all the elements, C and ^N" being exceptions. It is soluble in carbon disul- phide, but not soluble in water, in which it must be preserved. As phosphorus is an active, insidi- ous poison, workmen in match factories, by neg- lecting their teeth, are often afilicted with dental caries and necrosis of the lower jaw. Oil of tur- pentine and alkaline mouth washes are the best antidotes.

Phosphorus. 81

Phosphorus, heated to 250° (482°F.), is converted into a red powder of sp. gr. 214. The red variety is not soluble in carbon disulphide, is not poison- ous, has no odor, and does not oxidize in the air, and will not take lire until heated to 260° (500°F.).

There are two oxides of phosphorus : that pro- duced by oxidation, phosphorous oxide (P2O3), and that produced when phosphorus is burned in the air or in oxygen, phosphoric oxide (P2O5). Phosphoric oxide, united with water, forms phos- phoric acid :

P2O5 + 3H2O =: 2H3PO4

There are several kinds of phosphorus acids, but two or three only need be mentioned.

Ordinary phosphoric acid (H3PO4), often called orthophosphoric, is a syrupy liquid, of strong acid properties; its salts are called orthophosphates (as bone phosphate). It forms, with calcined zinc oxide (and also with cupric oxide), a coherent, hard ce- ment, used as a temporary tilling, or for strength- ening frail walls in cavities of teeth.

As phosphoric acid is formulated from 3 mole- cules of water, pyrophosphoric acid is formulated from 2 molecules, and m(?^aphosphoric acid from 1 molecule of water, thus :

P2O5 -( 3II2O = 2II3PO4, phosphoric acid;

82 Inorganic Chemistry.

P2O5 -f 2H2O = H4P2O7, pyrophosphoric acid;

P2O5 + H2O = 2HPO3, metaphosphoric acid.

The salts of the two latter are called pyrophos- phates and metaphosphates, respectively. The meta acid is also known as glacial phosphoric acid. It is a vitreous solid, readily soluble in water; will coagulate albumen, while the or^Ao variety will not. By the addition of water and a gentle heat, the glacial is converted into the ordinary so-called ortho-phosphoric acid.

Phosphorus and hydrogen unite indirectly, pro- ducing a compound phosphine (PH3), correspond- ing with ammonia (I^Hg), a colorless gas of garlic- like odor. It precipitates several metals from solutions, as phosphides.

Phosphine is usually prepared by filling a flask nearly full of an aqueous solution of caustic pot- ash, to which are added a few bits of phosphorus. The air above the solution in the flask should be driven out by drops of ether or a current of illu- minating gas. 4P + 3H2O + 3KH0 = 3KPH2O2 + PH3

Pot. Hydrate. Pot. Hypophosphite.

The PH3 is adulterated with traces of P2H4, which, on escaping from the tube in the water pan into the air, causes each bubble of the phosphine

Phosphorus. 83

to ignite with a brilliant flash, to form beautiful ascending rings of smoke, consisting of the oxid- ized phosphorus (P2O5).

There are two chlorides of phosphorus, the tri- chloride (PCI 3) and pentachloride (PCI5). The pentachloride is a solid substance, and is formed in the experiment showing the spontaneous ignition of phosphorus in chlorine gas.

84 Inorganic Chemistry.

CHAPTER XV.

CARBON.

Symbol, C. At. wt. 12. Sp. gr. 3-5, 2.15, 1-9.

Carbon is remarkable as existing in nature in three distinct allotropic forms, which have no physical properties in common, but whose chem- ical nature is the same. These three forms are known as the diamond, graphite^ and charcoal. Twelve (12) parts, by weight, of either of these varieties, united with oxygen, give us forty-foiu^ parts, by weight of the same compound (CO2).

Carbon also occurs extensively in nature, as in the carbonates, of which limestone, marble, chalk, and dolomite are examples. It is the characteristic element of animal and vegetable life — all organized tissues contain it — hence organic chemistry treats only of carbon in its relations to other elements.

The DIAMOND occurs in nature in crystals, more or less perfect, derived from the regular octa- hedron. It is the hardest substance known, and when cut and polished possesses high refractive and dispersive power hence its use as a costly gem. When diamond is heated in a gas incapable

Carbon. 85

of acting chemically upon it, it swells into a black porous mass resembling coke.

Graphite, or plumbago, also known as black lead, occurs in hexagonal plates, found as an ir- regular vein traversing ancient slate beds. It is also obtained in brilliant scales from melted cast- iron, on cooling. Graphite has a semi-metallic appearance, an unctuous feel, leaves a mark when drawn on paper, is a fairly good conductor of heat and electricity (which the diamond is not), and is used in the making of lead-pencils (therefore graphite), stove polish, crucibles, in electrotyping, and as a varnish for grains of gunpowder.

An impure, quasi graphite, gas carbon, formed in the retorts in manufacturing coal gas, is used in galvanic batteries, and for the carbon points of the arc electric light.

Charcoal includes all those varieties of coal found in nature, ordinary charcoal (of either ani- mal or vegetable origin), coke, and lampblack.

Coal consists of the remains of vegetable matter that once flourished on the earth's surface, and was subjected to a process of partial combustion, much like that by which common charcoal is pre- pared ; but much of the volatile principles yet re- main, made up largely of hydrogen. Cannel and soft coal contain the most hydrogen, and anthracite

86 Inorganic Chemistry.

the least. The elements, oxygen, sulphur, and nitrogen, are also found in coal, in varying pro- portions; and likewise earthy substances, which form the ash.

The varieties recognized merely as charcoal are produced by imperfect combustion of wood, bones, etc. Nearly all the volatile principles of the orig- inal substance are driven out, leaving a porous matrix. The ability of charcoal to absorb certain gases is due to this porosity. ^N'oxious gases, such as ammonia and sulphuretted hydrogen, are ab- sorbed in large quantity by freshly prepared char- coal, which are condensed within its pores and oxidized into harmless compounds by the oxygen which it also absorbs at the same time. In this way charcoal acts as a disinfectant.

Coke is the residue left in the retorts of the gas- works from the destructive distillation of coal.

Lampblack^ considered as the purest variety of amorphous carbon, is prepared by burning resin, tar, petroleum, or turpentine, in a limited supply of air, and collecting the smoke in suitable cham- bers, by which the soot, carbon, is deposited. Printer's ink, India ink, and black paint, are made from lampblack.

Combustion. — In the wide sense of the term, combustion means any chemical action that devel-

Carbon. 87

opes heat and light. Ordinarily, however, the meaning is restricted to the burning of substances in the air or in oxygen, and still further restricted by the understanding that the elements of the burning body are mainly carbon and hydrogen. This fact obtains in the burning of coal, or wood, or candle, or coal oil, or illuminating gas; and the chemical action, briefly stated, consists in the union of these elements, C and H, with the 0 of the air. Sufficient heat must be applied to start the process, which then continues, under favorable conditions, until the materials involved are com- pletely oxidized. An equation will enable us to understand fully, the general reaction :

C -f H2 + 30 = H2O 4- CO2

Water. Carbon Dioxide.

Common combustion may therefore be defined as " consisting of the union of the elements of the burning body with the oxygen of the air, resulting in the formation of water and carbonic acid gas." The earthy constituents of the wood or coal, such as potassium, are also oxidized at the same time, forming the " ash."

Illuminating gas, manufactured by destructive distillation of bituminous coal, is a mixture of free h^^drogen, methane, ethene, ethine, and traces of CO, CO2, N, and II2S.

Methane, marsh gas, or light carburetted hydro-

88 Inorganic Chemistry,

gen, CH4, is the lightest body known next to hydro- gen, its specific gravity being 0.5576. It occurs free in nature, being produced by decomposition of veg- etable matter confined under water, and may be col- lected by filling a wide-mouthed bottle with water and holding it over the bubbles which rise on stir- ring with a stick the mud at the bottom of marshy ponds — hence its name, " marsh gas." It is also the " fire damp " of the miners.

It is usually prepared in the laboratory by heat- ing sodium acetate and sodium hydrate.

1^2iQ^11^0^ + :N'aHO = 1^2i^C0^ + CH4

Sodium Sodium Sodium Methane.

Acetate. Hydrate. Carbonate.

Methane is a colorless, odorless and tasteless gas, and burns in the air with a faintly luminous flame.

Ethene, ethylene, heavy carburetted hydrogen (^2^4); produced in the decomposition of many organic bodies, is prepared by heating alcohol with strong sulphuric acid, which abstracts the ele- ments of water, thus :

CJI.O - H,0 = C,H,

Alcohol. Ethene.

Ethene is a colorless gas, much heavier than me- thane, its specific gravity being 0.978; it burns with a splendid white flame, and will unite with chlorine (C2H3CI) forming an oily liquid of ethereal odor, whence the name sometimes applied, '' oli- fiant gas."

Carbon.

89

The reader will kindly appreciate the fact, that these two gases, CH^ and C2 H^, are fair examples of the hydrocarbons that take active part with the oxygen of the air, in the process of ordinary com- bustion ; and that the products are, necessarily, water, (H2O), and carbonic acid gas, or carbon - dioxide (CO2).

The light from burning oil, or candle, or illumin- ating gas, or at the cheerful fireside, or the open grate, holding either wood or coal, or natural or artificial gas, consists substantially of the same chemical reaction, i. e., the union of hydrogen and carbon with atniospheric oxygen.

A jlame^ therefore, will vary in physical and chemical properties, according to the relative quan- tities of either the less or more dense hydrocarbon compounds, and the oxygen involved in the pro- cess. When the more dense or heavy gases burn in the air, the light evolved is superior to that given ofl[* by the less dense hydrocarbons, owing to the difierence, in afiinity, between the carbon and hydrogen of the burning gases, and oxygen.

Burning gases, containing relatively much hy- drogen, give oflT greater heat, while those that are relatively rich in carbon are deficient in heating, but correspondingly rich in lighting power.

The common, everyday hydrocarbon flame, is 8

90 Inorganic Chemistry.

divided, for convenience of description, into three parts :

1st. That which surrounds the wick of oil, or candle, or jet of gas burner, the zone of noncom- bustion.

2d. The zone of incomplete combustion, where hy- drogen mainly oxidizes, and where the particles of free Carbon are brought to a high state of incan- descence, by the heat developed by the burning hy- drogen, radiate their light — the luminous portion of ;the flame — and

3d. The area of so-called complete combustion, where carbon, with any remaining hydrogen, is also oxidized.

Active chemical union between the burning gases and the supporting oxygen of the air, takes place mainly on the surface of the resulting flame, the interior being hollow; such physical condition is due to the fact that the oxygen of the air is ex- hausted at the immediate surface, and is tlierefore unable to penetrate the interior of the flame ; but if the air (oxygen) be admitted to, and mixed with, the combustible gases, before ignition, as in the Bunsen burner, the extra oxygen, thus supplied, supports the simultaneous combustion throughout the flame, of both the carbon and hydrogen. Such

Carbon. 91

a flame is lacking in brilliancy, but possesses great lieating power.

The same principles apply to the mouth blow- pipe flame. Air (oxygen), is blown by the cheeks, into the interior of the flame, wdiich resolves the latter into two chief parts : a bluish inner cone and an outer cone. The outer cone is named the oxi- dizing area, because certain metals, when heated in it, become oxidized. The apex of the inner cone is possessed of great heating power, and is called the reducing portion of the flame, because certain metallic oxides, when heated at that point, are re- duced to free metal and free oxygen. A little practice with the blow-pipe, under proper instruc- tions, will enable the dental student to easily solder pieces of brass or copper, these metals being good substitutes for silver and gold in experimental practice.

The heat of combustion, ordinary or special, is measured in heat units ; one unit being the quan- tity of heat needed to raise one gram of water from 0° to 1°. Hydrogen burning in oxygen, furnishes 34,462 heat units, and carbon oxidizing, 8,080 units; that is to say, 1 grain of hydrogen, or of carbon respectively, in burning in oxygen, would raise the temperature of 34,462, or 8,080 grams of water from 0° to 1°.

92 Inorganic Chemistry.

CHAPTER XVI.,

CARBON— Continued. Cakbon DioxiDE.-Carbon and oxygen form two compounds, the monoxide (CO), and the dioxide (CO ) The latter compound is also known as car- bonic acid gas. It is a substance of frequent oc- currence and wide distribution, being a product ot ordinary combustion, and fermentation, and putn- cation of vegetable and animal tissues. From the bodies of living animals it is exhaled by means ot the lungs, in respiration. It is usually set free, when carbonates are decomposed, and is the im- portant constituent of the atmosphere, which sup- plies carbon to the vegetable kingdom.

Carbon dioxide is prepared for experimental purposes, or for producing, under pressure, the effervescence in soda roatcr, by reaction between a carbonate and a dilute acid, usually hydrochloric or sulphuric, as the following equation will show : n po + H SO, = CaSO^ + H^O + CO,

CaCO, + ^iXavtc calcium* Water. Carbm,

SSte. iclS""™ Su.p.ate. B.ox .

Carbon dioxide is a colorless, odorless gas, and possesses a slightly acid taste. It is one-and-a- half times as heavy as air, and twenty-two times

Carbon. 93

as heavy as hydrogen. It dissolves somewhat in water at the ordinary pressure and temperature of the air, but as the volume of a gas is inversely as the pressure, great quantities of COg can he confined in w^ater under pressure, as is seen iu soda water, certain mineral waters, sparkling wnnes, and beer, which, on exposure to the air, rapidly lose their excess of CO2, and thereby soon become flat and insipid.

Carbon dioxide interferes with combustion by superseding the supporting oxygen, as is noticed in the action of the '' Babcock Extinguisher."

Animal respiration is also affected by the pres- ence of an abnormal quantity of carbon dioxide, although it is not of itself a poison; it simply acts like w^ater, or nitrogen, by preventing the due aeration of the blood; it often accumulates at the bottom of old wells, brewery vats, etc., and in such places its presence may be detected by lower- ing a lighted candle, which, if extinguished, will indicate an atmosphere dangerous to animal life. It is the choke-damp of the miners.

Carbonic acid is formed by the union of water and carbon dioxide under pressure.

H2O -f- CO2 = II2CO3

Carbonic Acid.

This acid does not exist as a commercial sub- stance, like nitric, or other acids, because on re-

94 Inorganic Chemistry.

moval of pressure, it decomposes into water and carbon dioxide.

H2CO3 = H,0 + CO,

Carbonic Acid.

The salts of this acid, known as carbonates, are easily disrupted by heat, as well as by even, weak acids. Calcium carbonate, in the form of lime- stone, marble, chalk, oyster shells, etc., when heated, yield lime and carbon dioxide.

CaCOg + Heat = CaO + CO2

Calcium Lime

Carbonate.

Carbon monoxide (CO), known also as carbonyl, and too frequently as carbonic oxide, is a combus- tible gas, odorless, colorless, and tasteless, and actively poisonous ; one per cent in the atmosphere is considered dangerous. It may be prepared by various methods, but it is probably never produced synthetically. Some of the carbon dioxide formed during combustion, when arriving at the surface of the heated coal, suffers reduction (CO2 + C = 2C0), at which point the resulting CO, meeting with at- mospheric oxygen, unites with the latter, burning with ablue flame, andproducingC02. CO-j-O^COg.

Where the combustion is confined, as in certain anthracite stoves and furnaces, a portion of the CO may escape oxidation, and pass through the heated cast-iron to the surrounding air, causing serious annoyance to the occupants of the room.

Carbon. 95

Cigarette smokers are probably injured more by inhaling carbon monoxide (CO) than by any other cause connected with the habit. This gas is formed at the heated end of the burning cigarette, and which, when inhaled, enters the circulation and induces destructive chemical changes in the blood.

Carbon disulphide (CS2) is formed synthetically by passing a stream of sulphur vapor over red-hot charcoal. The commercial carbon disulphide has an exceedingly nauseous odor, but, if pure, the odor is rather pleasant, suggestive of ether. It is a clear liquid, of specific gravity, 1.29. Its vapor Hiixed with air is explosive, and the compound itself is very combustible, yielding carbon dioxide and sulphur dioxide, CS2 + 60 = CO2 + 2SO2.

Carbon disulphide owes its importance to its solvent properties. It easily dissolves such sub- stances as caoutchouc, phosphorus, sulphur, oils, and fats, and is used largely for extracting oils from seeds and fats from animal refuse, and in the vul- canization of rubber.

With N, carbon forms one compound named cy- anogen (CX), to be described under "Organic Chemistry."

96 Inorganic Chemistry,

CHAPTER XVII.

BORON.

Symbol, B. Sp. gr. 2.68.

Boron is a constituent of many minerals. It may be obtained in two modifications. The first is a soft, dark brown powder, analogous to amorphous carbon, slightly soluble in water, and fusible in the oxy-hydrogen flame. The second variety is obtained in quadratic octahedral crystals, varying in color from yellow to garnet red; in- fusible, and nearly as hard and as highly refractive as the diamond.

Boric oxide, B2O3, is formed whenever boron is burned in the air or oxygen. United with 3 molecules of water, it forms boric (ortho-boric) acid,

B2O3 + 3H2O =: 2H3BO3.

Boric Acid.

Boric Acid. — Boric acid is usually obtained from solution of borax, in boiling water, by sulphuric acid. Occurs in white crystalline scales, soluble in water and alcohol, and possesses antiseptic prop- erties.

Boron unites with H to form a o^aseous com-

Silicon. 97

pound, BII3, resembling NH3 and PH3. With F it forms a colorless gas, and with CI a volatile liquid ; but by far the most important compound of boron is borax (Xa2 0 (6203)2, which will be considered in connection with sodium.

SILICON.

Symbol, At. Wt. Sp. Gr.

Si. 28. 2.49.

Inasmuch as we began the study of the non- metallic elements with oxygen, it is meet that we conclude the subject with the next most abundant ingredient of the earth's surface, namely, silicon, sometimes called silicium. It is obtained by heat- ing together metallic potassium and potassium sili- cofluoride, 4K + l^^^'^"^^ = 6KF + Si.

Like carbon, silicon may be obtained in three different modifications. One is an amorphous dark brown powder. The second consists of hex- agonal plates resembling graphite, and the third variety crystallizes in octohedrons of exceeding hardness. It fuses only at very high temperatures, and is insoluble in all acids, except hydrofluoric. The isolated element has no practical importance.

Silicon combined with oxygen, and also with

potassium, aluminum, and other metals, enters

largely into the structure of the solid crust of the

earth. 9

98 Inorganic Chemistry.

The oxide of silicon (SO 2), known as silica, and when in powder, as silex, is the principal earthy material of our planet, occurring more or less pure in sandstone, quartz, or rock crystal, amythyst, agate, cornelian, chalcedony, and the beautiful opal. In combination with certain metallic oxides, it forms a class of salts called silicates, of which by far the largest variety of minerals consist. Sili- con oxide is found in animal tissues ; it stiffens the stems of the various grasses and growing grains, and is also found dissolved in the waters of many thermal springs. It has a specific gravity of 2.6. The natural crystal is sufficiently hard to scratch glass ; it is but slightly soluble in water, and is un- affected by acids, except hydrofluoric.

Si02 is an acid oxide. When sand is fused with sodium or potassium carbonate, a reaction ensues by which a silicate of these metals is formed.

Si02 + Na2C03 = Na2Si02 + CO2.

Sodium Silicate.

The silicates of sodium and potassium are known as ID ater glass. They are soluble in water, but the silicates of the other metals are in general, insolu- ble. Porcelain and glass are artificial mixtures of silicates. Porcelain (artificial) teeth, consist of aluminum silicate and the double silicate of alum- inum and potassium. Window glass is a silicate of calcium and sodium. Bohemian glass. is a sili-

Silicon. 99

cate of calcium and potassium. Crystal or flint glass, is a silicate of potassium and lead.

Silicon unites with hydrogen to form a colorless gas, SiH^, analogous to CH^. It unites with chlorine, bromine, and iodine, SiCl^, SiBr4, 81X4, corresponding to carbon chloride, bromide, and io- dide It also forms a chloroform, SiHClg, similar in some respects to ordinary chloroform, CHCI3. Indeed, although silicon and carbon are appar- ently widely separated in nature, being the char- acteristic elements of the mineral and organic kingdoms respectively, they are very near akin in their chemical naturCi.

If a strong solution of sodium or potassium sili- cate be acted on by hydrochloric acid, a jelly-like substance will separate out. This substance is known as or^Ao-silicic acid, H^SiO^. By losing a molecule of water it becomes meta-sWicic acid, 1128103. If the mixture of hydrochloric acid and water glass be sufficiently dilute, no separation of the silicic acid will take place. A separation, how- ever, can be beautifully and instructively accom- plished by dialysis. The dializcr, consisting of a taut membrane of bladder or skin parchment, placed in the solution, whereby the sodium or po- tassium chloride will diffuse through the membrane, leaving a clear, tasteless solution of silicic acid.

100 Inorganic Chemistry.

which in time solidifies to a jellj. Crystallizable bodies like salt, sugar, etc., diffuse readily through the dializer, while non-crystallizable bodies, like jellies, glue, albumen, etc., do not pass at all. These two classes are termed respectively crystal- loids and colloids.

PAR.T SECOND.

INORGANIC CHEMISTRY.

CHAPTER I.

CHEMICAL PHILOSOPHY— i^e'SMw^d.

Now that we are acquainted with some of the chemical and physical properties belonging to a few of the elementary forms of matter, we will be better enabled to understand more clearly the fol- lowing additional facts in chemical philosophy.

The atomic theory of Dalton, which assumes that matter is made up of ultimate particles, called atoms, clearly explains the known laws of chemical reactions. As atoms are individually indivisible, whole atoms, or multiples of them, must be in- volved in chemical union. A chemical compound is definite in its nature, i. e., each of its molecules, of which the mass is composed, must contain the same kind and number of atoms, similarly ar- ranged.

We do not know the real weight of atoms, but as hydrogen is the lightest body, and therefore taken as unity, the comparative weights of the atoms of the several elements can be ascertained.

(101)

102 Inorganic Chemistry.

The real weights of the atoms of the several ele- ments are fixed and unchangeable for each; it fol- lows that molecules, each containing the same kind and number of atoms, producing a given compound, must be alike in weight. Equal weights of water, under equal conditions, will con- tain the same number of molecules; hence the

116

molecular formula, H2O, not only truly represents the relative quantities of H and 0, but also the comparative weight of a given quantity of water. The molecular weight is the sum of the atomic weights. The molecular weight of water is there-

32 16

fore 18; that of SO3 is 80; these two substances combine with each other in the above proportions to form a molecule of H2SO4, whose weight is the sum of 18 + 80 r= 98.

Aside from the known relative weights, or mul- tiples of them, in which the elements unite with or displace each other, there are other relations between the accepted atomic weights, and certain physical phenomena, which prove the correctness of the former.

The remarkable relation between the atomic weights of the elements, and their capacity for heat, called specific heat, or atomic heat, is ex- pressed by the statement that the products of the specific heats of the elements into their atomic weights,

Chemical Philosophy. 103

give a nearly constant quantity, the mean value being 6.4. The slight variations noticed are no doubt due to unavoidable errors in experiment. In other words, all atoms have equal capacities for heat; the same amount of heat that will raise 1 part by weight of hydrogen one degree, will raise 7 parts by weight of lithium, 16 of oxygen, 23 of sodium, 56 of iron, 108 of silver, 197 of gold, etc., one deo^ree.

In many cases, the molecules of compounds which crystallize in like form, called isomorphous, are supposed to contain an equal number of atoms ; thus, certain sulphates are isomorphous with cor- responding selenates ; sesquioxide of iron, Fe203, is isomorphous with sesquioxide of aluminum, AI2O3 ; and in case of doubt as to the correct atomic weight of an element, as for instance of aluminum, this relation is appealed to.

All molecules, according to the law of Ampere, have the same size; that is, all molecules, when in the gaseous state, under equal conditions of heat and pressure, occupy the same volume, or same amount of space. The composition of gaseous elementary molecules can therefore be expressed in volumes, as well as in atoms. The molecule of hydrogen is assumed to contain 2 volumes, or 2 atoms, of hydrogen, IIII ; the molecular weight of

104 Inorganic Cheynistry.

hydrogen is therefore 2, twice that of a single atom of hydrogen ; and as this element is taken as unity, its density is one-half its molecular weio-ht or its molecular volume is equal to 2 atoynic vol- umes. Those elementary gases or vapors whose molecules are supposed to contain 2 volumes, or 2 atoms, have a density, referred to hydroo-en as unity, equal to one-half their molecular weights, or identical with their atomic weights.

DENSITY. DENSITY.

Hydrogen 1 Sulphur 32

Oxygen 16 Bromine 80

Chlorine 35.5 Iodine 127

Since the molecular weight represents the weight of two volumes, as II— H, 0=iO, and density represents the weight of one volume, the density of any homogeneous vapor, either element- ary or compound, is one-half its molecular weight.

Ordinary oxygen, whose molecular formula is 0=0, has a molecular weight of 16 -f 16 =r 32 ;

its density is one-half of 32, or 16. Ozone /^\

' O 0

has a molecular weight of 48; its density is 24.

Carbon dioxide, whose formula is CO2, has a molecular weight of 12 -f 32, or 41; its density is 44 -f- 2, or 22. Conversely by knowing the dens- ity, the molecular weight can be obtained by mul- tiplying by 2.

Chemical Philosophy. 105

It is also noticed that the gaseous product of the union of two elementary gases, when combining in equal volumes, retains tlie original volume of its constituents; as 1 vol of H and 1 vol. of CI form 2 vols, of HCl. When 3 or more vols, of combin- ing gases, elementary or compound, enter into combination, condensation takes place to 2 vol- umes, as

2 vols, of H and 1 vol. of 0 form 2 vols. H2O ;

1 vol. of ethyl CH5 and 1 vol. of CI form 2 vols. CH5CI;

2 vols, of ethyl (CH5)2 and 1 vol. of 0 form 2 vols. (CIl5)20.

Hence the law of Avogadro: The molecules of all gases, simple or compound, occupy equal volumes ; or equal volumes of all gases contain equal numbers of molecules. The molecular formula of compound gases (or vapors), and the atomic weights of the elements contained in them, can, by noting the vapor density, be determined by this law.

Equivalency. — Certain elements unite with each other in only one proportion ; they form, with each other, but one compound. Their atoms have only one point of attraction ; their atomicity or valency IS one. These elements are called monogenic or monads, signifying one. The other elements are called polygenic. The atoms of the monad ele-

106 Inorganic Chemistry.

merits are equivalent to each other; the atoms of the polygenic elements are equal in combining, or substituting power, to two or more atoms of the monads. One atom or volume of H, and one atom or volume of CI unite; they form but one com- pound, HCl ; they are both monads. One atom of Na will displace H and take up with the CI : HCl + Na =r NaCl + H.

The valency of ^N'a is, therefore, the same as H and CI ; it is monogenic. The atom of 0, how- ever, is equal in combining power to two atoms of H, Na, or any other monad; oxygen, therefore, is a dyad element. One atom of 0 and two atoms of H unite (H2O). One atom of Na will drive out one atom of the hydrogen and take its place; the one atom of oxygen being able to attract and hold together the two unlike atoms in a homogeneous molecule :

H2O + Na =: H^aO 4- H.

One atom of Zn (65 parts by weight) requires two molecules (73 parts by weight) of HCl to sat- isfy its combining power:

Zn -f 2HC1 = ZnCl2 + 2H.

Zinc, accordingly, is a dyad. When zinc is oxid- ized, the molecule produced contains one atom each of dyad zinc and dyad oxygen: Zn + 0 = ZnO.

I

Chemical Philosophy. 107

This difference in the number of points of at- traction or saturating power belonging to each atom of the various elements is often denoted by placing Roman numerals, or dashes above or to the right of the symbols, as —

Univalent elements, or monads, as H'

Bivalent elements, or dyads, as.. ,0"

Trivalent elements, or triads, as Au'"

Quadrivalent elements, or tetrads, as...C'^ Quinquivalent elements, or pentads, as..P^

Sexvalent elements, or hexads, as Cv"^

Elements of even equivalency, namely, the dyads, tetrads, and hexads, are classed under the general term artiads^ signifying even; and those of uneven equivalency, the monads, triads, and pentads, are called perissadsy which means uneven.

108 Inorganic Chemist?^,

CHAPTER 11.

GRAPHIC FORMULA. Formulae are sometimes written graphically, that is, a number of lines or bonds, connecting the sym- bols, indicating the equivalency of each; thus:

Hydrochloric acid, HCl H CI

Water, H2O H— 0— H

Carbon dioxide, CO2 0— C— 0

CI

Am. Chloride, NH.Cl "^^iIt-^"^

' H^ \H

0

Nitric Acid, HNO3 N 0— H

II 0

0 0

Zinc Nitrate, Zn(N03)2 N— 0— Zn— 0— N

A II

0 0

These graphic formulae are often abridged by the use of dots only, tlius :

H.Cl H.O.H 0..C..0

By observing the above diagrams, it will be no- ticed that the units of attraction belonging to each atom are satisfied by union with those of other

Chemical Philosophy. 109

atoms. And, accordingly, it is found that in all saturated molecules, the sum of the perissad atoms is always even. A molecule may contain 2, 4, or 6, etc., monad atoms, as in PICl, H2O, CH^, C2Hg, etc.; or 1 triad atom, as Au'", and 3 monads, as in AuClg ; or 1 pentad and 5 monads, as in l^H^Cl; but never an uneven number of perissad atoms. This is the law of even numbers.

For the same reason the molecules of the peris- sad elements consist of an even number of atoms. The molecule of hydrogen contains two atoms H — 11. So also the molecule 'of chlorine CI — CI; the molecule of phosphorus contains four atoms,

P^P As=As

II II So also the molecule of arsenic, 11 11 r=P. As=As

The molecules of dyad elements, however, may contain either an even or an uneven number of atoms, as will be observed on again submitting the following :

.A,

Ordinary oxygen. Ozone.

The true equivalency of an element may be ex- pressed as that which represents the maxim,um number of monads atoms, with which one atom of it can com- bine. The molecule, ammonium chloride, NH4CI, shows one atom of IST saturated by five monad

110 Inorganic Chemistry.

atoms; no other atom or atoms can unite with the above group. Accordingly nitrogen is a pentad, i, e., its atom is equal to five monad atoms. One atom of dyad oxygen can take up with no more than two atoms of monad hydrogen H2O''.

When variation in the valency of any element occurs, it always takes place by 2 units. So that an element may appear as a monad in one com- pound, a triad in another, and a pentad in still an- other; or an element may act as a dyad in one case, or a tetrad in another, and a hexad in another. For instance, nitrogen appears to be a monad in nitrous oxide ^2^? ^ triad in ammonia NH3, and a pentad in ammonium chloride NH^Cl; sulphur is a dyad in dihydrogen sulphide HgS, a tetrad in sulphurous oxide SO2, and a hexad in sulphuric oxide SO3.

In compounds where the full valency of the ele- ment is not exhibited, as in NH3, ammonia, the two units belonging to I^ uncombined, probably unite with each other, for the time being; but the molecule of ammonia is willing to unite directly with HCl, forming NH4CI, wherein the full va- lency of K" is satisfied. Tetrad sulphur in SOg can be oxidized into SO3, becoming thereby a hexad.

A perissad element is alwa3^s a perissad; an artiad element, always an artiad, inasmuch as vari-

Chemical Philosophy, 111

ation in valency of either class, when it does occur, is always by 2 units.

The statement that the true valency of an ele- ment is determined by the composition of its hy- drides, chlorides, etc., rather than by its oxides, etc., will be appreciated if we consider the part dyad atoms play in combination. For example, dyad 0" can enter the saturated molecule of water

II — 0 II without disturbing the existing atomic

value of hydrogen, thus H — 0 — 0 — H, because any dyad atom (or radical), introduces one unit of equivalency into the compound which it enters, and neutralizes another, leaving the valencies the same as before. Potassium is a monad, because one atom of it unites with only one atom of chlo- rine, K — CI, and in no other proportion ; but in ad- dition to its corresponding oxide, K — 0 — K, there is a tetroxide of potassium K — 0 — 0 — 0 — 0 — K, wherein the valency of the K' is seen to be the same as in its normal oxide. Any other dyad atom (or radical) can act in the same way.

When two or more atoms of a polygenic element are present in the same molecule, the element in question may seem to possess less than its normal valency. Carbon is a tetrad inasmuch as four atoms of hydrogen or other monad, are as many as one atom of carbon can saturate, (CH^); there are,

112 Inorganic Chemistry.

however, a great many other compounds of C and H alone, whose molecules contain more than one atom of carbon, and where the C appears to pos- sess an atomicity of less than four. This is owing to the units of valency, belonging to the carbon atoms, not saturated by the hydrogen (or in other cases by atoms of other elements), uniting with, and so satisfying each other. One or two examples will suffice :

In methane, CH^, carbon is a tetrad ; in ethane, CgHg, carbon appears to be triad; in ethene, C2H4, it appears to be a dyad, and in ethine, C2H2, a monad. The following diagrams will readily explain the apparent discrepancy: H H

I I

H— C— H H— C— H H— C— H C— H

I I II III

H H— C— H H— C— H C— H

k

Methane, Ethane, Ethene, Ethine.

The same faculty, ot mutual combination of otherwise free units, is possessed by the atoms of other polygenic elements, but not in as high a de- gree as with those of carbon.

Radicals. — Radicals may be defined as residues, obtained by removal of one atom or more from a saturated molecule. There are elementary and

Chemical Philosophy. ■ 113

also compound radicals. A perissad atom, as an atom of hydrogen, H, is an elementary radical, and probably never exists free ; such atoms, when set free from combination, unite either with each other or with atoms of another kind to form again satu- rated molecules. A mass of hydrogen, for instance, does not consist of an aggregation of uncombined atoms, H, H, H, H, H, but of a great number of molecules, each containing two atoms, chemically united, H — H. Suppose a molecule of hydrogen, H — H, be acted on by a molecule of chlorine, CI — CI, the reaction would be as follows : H— H + CI— CI = 2HC1

The two atoms (radicals) of the hydrogen mole- cule, and the two atoms (radicals) of the chlorine molecule, would become separated by the influence of the superior chemical attraction between the unlike atoms (radicals), and recombination take place, resulting in the production of two mole- cules of hydrogen chloride, as seen in the equation.

Again suppose, these latter two molecules, 2HC1, be brought under the influence of a molecule of sodium (l!^a — Na), another change would occur, 2IIC1 -f Na— Na = 2XaCl -f H— II. The 2C1 rad- icals would leave the hydrogen and take up with the 2 Na atoms (radicals), forming 2 molecules of

sodium chloride, letting the 211 atoms go free, 10

11-4 Organic Chemistry.

which, in the absence of more attractive radicals of some other kind of matter, would be satisfied to unite with each other, and give birth again to a molecule of hydrogen.

Compound radicals are unsatisfied groups of two or more unlike atoms, and have a valency corre- sponding to the number of equivalent units removed from a saturated molecule. H — 0 — H (water), is a saturated molecule; if one of the hydrogen atoms be removed, the resulting group, — 0 — H (hydroxyl), will evidently have the same combin- ing power as the divorced atom of hydrogen (H — ). Hydroxyl is, therefore, a univalent (monad) com- pound radical, having one free bond. It exists in all the hydrates and in many other compounds.

Sodium thrown on water removes an equivalent quantity of hydrogen, and takes its place, in union with the resulting hydroxyl : [N-a— N"a + 2H-0— H = H— H + 2]^a— 0— H

Sodium Hydrate.

The names of compound radicals of uneven valency (monads, triads, etc.) end in yl; they do not exist free, but the instant of their development, if unaffected by radicals of another kind, they tend, like perissad atoms, to combine among them- selves. Free hydroxyl is not known, but a com- pound whose molecules are made up of 2 hydroxyl groups, H — 0 — 0 — H, is a well known substance.

Chemical Philosophy. 115

Compouuds in general are often formulated so as to show their molecular constitution by radicals. Thus, nitric acid, HNO3, may be considered as con-

O

II sisting of the 2 radicals, H— 0— and IST = HO.NO2.

II O

Water is analogous in formula to sodium hydrate,

H.OH Xa.OII. The graphic formula of phosphoric

Water. Sodium hydrate.

0— H

acid is 0 = P— 0— H

^0-H, etc.

An understanding of the part played by radicals in the carbon compounds included in organic chemistry, is most important, and their relations may be somewhat studied in this connection to advantage.

The atom of carbon has four points of attraction ; it can not, therefore, take up more than four atoms of hydrogen, or other monad radical. Methane, C'^'H^, is the typical saturated hydro-carbon. If one of the four atoms of hydrogen be removed, the residue will, of course, be O^'H'g, named methyl^ which has the same valency as the atom of hydro- gen, or one unit, capable of uniting with one atom of chlorine, for instance, to form methyl chloride, CH'3C1. Two atoms of hydrogen removed from

116 Inorganic Chemistry.

methane, CH^, leaves the dyad radical methene, CW ^^ able to take up two atoms of chlorine to form methene chloride, CH''2^^2- I'h^ee atoms of hydrogen removed from methane, results in the trivalent radical methenyl, CH'^', which in union with three atoms of chlorine, produces methenyl chloride, CHCI3 (chloroform), and if all four of the hydrogen atoms in methane be driven out, the tet- rad carbon atom remains to be saturated by four atoms of chlorine, CCI4, or other monad element, or by two dyad radicals, or by one triad and one

monad radical, — C — .

I

Allusion has been made to the non-interference

of dyad atoms, or radicals, with the equivalent

values of the atoms or radicals, in those saturated

molecules which they may enter.

H

I The dyad compound radical, methene, — C —

J,

like an atom of oxygen — O — , can evidently join itself to an already satisfied molecule, because it is able to neutralize one unit of valency in the compound it enters, and introduce another, as may be understood by the following diagram :

Chemical Philosophy. ^ 117

H

H H-C— H

CH4 or H-C— H -f H— C— H= H— C— H or Q^B.^

I I I

H H

Methane. Methene. Ethane.

Ethane, CgHg, is methane CH4, plus the dyad radical CHg. If we presume to abstract one atom of hydrogen from ethane, we will have the univa- lent radical ethyl Q^W ^, capable of joining itself to an atom of chlorine, as in ethyl chloride C2H'5^C1, or to hydroxyl, as in alcohol, C2H'5'OH, or two such groups, to — 0 — , as in common ether (CH,),0.

Hydrogen is not the only element involved in removal from saturated molecules, to form radicals. Indeed it is only necessary to assume a number of units of valency abstracted from any saturated molecule, in order to obtain a radical of corre- sponding combining power; and it is evident, from their mode of derivation, that the number of com- pound radicals which are capable of existence is without limit. A great many of them are known to individually enter into the formation of special classes of compounds, like the salts of the same metal, enabling us to comprehend clearly the rela- tions that exist between vast numbers of organic compounds, which otherwise would be impossible.

118 Inorganic Chemistry.

CHAPTER III.

MATERIA MEDICA.

Materia Medica is that part of therapeutics which includes the study of the origin, physical and chemi- cal nature, therapeutic and toxic effects, local and general, of materials employed for the cure, allevia- tion, or prevention of disease.

Although it is not often incumbent on the den- tist to prescribe medicines for internal administra- tion, it is proper that he should know the general effects, dosage, incompatihles and antidotes, when so exhibited, of those drugs he uses in his practice as local agents, inasmuch as a large majority of them are active poisons.

By knowing these facts he can make judicious selection and combination of materials for any pre- scription that, in his judgment, will best suit the case in hand. He would not, for instance, order a combination of any soluble chloride with silver nitrate, or any vegetable astringent, with persalts of iron; or use, even topically, excessive quantities of arsenic, or tincture of aconite root, etc.

The art of writing decent prescriptions is a seri- ous labor to the average student. If we could pre-

Materia 31edica. 119

vail upon him to discard in toto the signs and symbols of the old system of weights and measures and adopt the metric system exclusively, he would find the task much easier; and if, as occasionally happens, he be deficient in a knowledge of the Latin language, he should take courage, and realize tliat very few Latin phrases, or abbreviations, are needed in prescribing, as the following sufficient presentment of them will prove :

A; aa. Ana; of each.

Ad. add., Addendus ; to be added.

Ad lib.. Ad libitum ; at pleasure.

Alb., Albus ; white.

Aq., Aqua; water.

Aq. dest.. Aqua destillata; distilled water.

Chart., Charta; paper.

Dil., Dilutus; diluted.

F., Ft., Fiat; let a — be made.

Fl., Fluidus; liquid.

Fol., Folium; a leaf. Folia; leaves.

Gr., Granum; a grain. Grana; grains.

Gtt., Gutta; a drop : Guttse ; drops.

Ilyd., Hydro ; water.

Ilydr., Hydrargyrum; mercury.

Inf., Infnsum ; infusion.

M., Misce ; mix.

Mist., Mistura; a mixture.

120 Inorganic Chemistry.

No., Numero ; in number.

01., Oleum ; oil.

P., Pulvis; powder.

Ph., Pharmacopoeia.

Pil., Pilula; a pill ; pilulse, pills.'

Q. S., Quantum Sufficiat ; as much as is sufficient.

15^., Recipe; take.

Rad., Radix ; root.

Rect., Rectificatus ; rectified.

S., or Sig., Signa ; write.

Ss., Semis; half.

Solv., Solve ; dissolved.

Spr., Spiritus; spirit.

Tr., or Tinct., Tinctura; tincture.

U. S. P., United States Pharmacopoeia.

In writing a prescription containing a number of substances, it is proper to place the most impor- tant article in the combination, first, as the basis; the adjuvans or assistant to the base, next; the cor- rective^ if the two first have certain objectionable properties, as taste or smell, comes next; and finally the vehicle, to give form and elegance to the whole. The following will serve as an example :

R. Acidi salicylici. Basi^.

Sodii bi boras, aa 1.00 Gm. (gr. xv), Assistant.

Spts. rect., 4.00 CC. (f^i), Corrective.

Aq. rosse q. s. ad 125.00 CC (f^iv), Vehicle,

M. S. Use as a general mouth wash.

Materia Medica. 121

Apothecaries' weights and measures.

Pound. Ounces. Drachms. Grains.

Lb. 1 = 12 = 96 5760

§i = 8 = 480

3i = 60

Fluid measure.

Pint (Octarius).	F, Ounces.		F, Drachms.		Minims,
01	= 16	=	128	=	7680
	ill	=	8	=	480
			f3l	:;:z:	n 60

Metric System.

The meter is the basis of the metric system, and is the standard unit of linear measurement of that system.

The meter is the 10 millionth part of the distance from the equator to the pole (the earth's quadrant) ; it is about 10 per cent longer than the yard.

The unit of fluid measure is the liter — the cube of y^^ meter (one decimeter), or 1,000 cubic centi- meters; it is equal to about 32 fluid ounces.

The cubic centimeter (C.C.) is equal to about 15 minims.*

* Exactly 16.231 minims. Approximative comparison is suf- ficient for our purpose.

11

122 Inorganic Chemistry.

The Gram is the metric unit of weighty and repre- sents the weight of 1 cubic centimeter of water at its maximum density (4° C— 39° F). The gram is equal to about 15 grains. Fractions over 15 grains and 15 minims, with reference to the gram, and to the cubic centimeter, may be ignored.

We accordingly have :

1 Gram equal to 15 grains.

4 Grams equal to 1 drachm.

1 Drachm equal to 4 Grams.

1 Cubic centimeter equal to 15 minims.

4 Cubic centimeters equal to 1 fluidrachm.

1 Fluidrachm equal to 4 cubic centimeters.*

The term flaigram has been suggested as more euphonious than cubic centimeter, but has not been generally accepted. Inasmuch, however, as the gram expresses the weight of 1 cubic centimeter of water, the term fluigram is not inappropriate, and will be used by us hereafter instead of cubic centimeter : fluigram abbreviated f. Gm, and Cubic centimeter CC, mean, therefore, the same measure of any liquid.

Gram should be written with a capital " G," ab- breviated Gm ; and in order to avoid mistaking this sign for gr, which latter is always written with a small " g," it is proper to place the Arabic

* Slightly changed from Oldberg.

Materia Medica. 123

numerals before the sign ; thus, 10.00 Gm (ten Grams). Apothecaries' weights and measures (old system) have their signs followed by Roman nu- merals, thus, gr X (ten grains).

in writing prescriptions according to the metric system, the only signs needed are the Gm and fGm; and fractions of them are stated decimally, in the same way we write our divisions of federal money, thus:

10.00 Gm (ten grams), analogous to $10.00 (ten dollars) ; 0.05 Gm (five centigrams), analogous to $0.05 (five cents).

If we regard the Gm or fGm, as corresponding in this respect to our dollar, wq can appreciate the relation most easily by the following comparison :

Gm $

1 .00— One Gram . 1 .00— One dollar.

.50 — Fifty centigrams. .50— Fifty cents.

.02— Two " .02— Two "

.001— One milligram. .001— One mill.

In speaking of the divisions of the gram, the same terms may be employed that are used in speaking of money matters. For instance, 0.10 Gm = one dime; or 0.10 fGm = one fiuidime. The fluidime may be considered the minimum quantity for liquids, equal to IJ minims, and the mill, the

124 Inorganic Chemistry.

smallest representative of weight, equal to g^^ of a grain. -^

The prefixes used in the metric system are sometimes convenient in speaking of weights and measures, but in prescribing the}^ need not be written, the Arabic numerals being sufficiently ex- plicit. As, for instance, with reference to any unit in the metric system.

Myria means 10.000

Kilo '' 1.000

Hecto " 100

Deka " 10

Deci " 0.1

Centi " 0.01

Milli " 0.001

The following approximate equivalents are mainly taken from Oldberg, and are sufficiently accurate to answer all purposes of mere com- parison :

Troy Grains (or Minims), Grams (or Fluigrams).

^5 0.001 (1 mill)

i 0.03 (3 cents)

1 0.06 (6 cents)

U 0.10 (10 cents)

10 0.65 (65 cents)

15 1.00 (1 Gram), (or fGm)

30 2.00 (2 Grams), (or fGm)

60(1 Drachm) (Fl drachm)) . .4.00 (4 Grams), (or fGm)

Materia Medica. 125

Troy Ounces (or Fluid Ounces). Grams (or Fluigrams).

1 30.00 (30 Gm or fGm)

4 120.00 (120 Gm or fGm)

With the foregoing preliminaries in materia medica, more or less mastered, our hope is now to study carefully the medicinal properties, in con- nection with the chemical history of the various metallic salts, and organic compounds, that may be deemed worthy of notice.

We shall endeavor to systematize the study, by tirst presenting their physiological and therapeutic effects, if any, when applied locally ; then, when taken internally, their influence on the brain and nervous system generally; on the circulation, respiration, temperature, and on the secretions ; naming the principal diseased conditions in which they are indicated; and, finally, their antidotes and dosage, with an occasional prescription.

126 Inorganic Chemistry.

CHAPTER IV.

METALLIC ELEMENTS.

All those elements, studied in Part First, with the exception of hydrogen, are classed as non- metallic; those elements yet to be considered, with the exception of arsenic, are classed as metallic. Arsenic seems to be the connecting link between the two classes.

A few of the metals, as gold and platinum, are found in nature, in the metallic state ; the large majority, however, are found united with non- metallic elements, forming oxides, chlorides, car- bonates, etc., wherein the metallic i)roperties are masked, and which constitute the ores from which the metals involved, are obtained.

Some of these elements, as gold, iron, copper, etc., are most useful when in the metallic state ; and others, as potassium, calcium, barium, etc., are most important when in combination with non- metallic elements.

When metals unite with non-metals, true chem- ical compounds are formed. When metals unite among themselves (except with arsenic, and those closely allied to it), the combination does not

Metallic Elements. 127

produce a true chemical compound, but an alloy^ wherein the metallic nature is preserved. Many alloys are extremely useful, and exhibit desirable properties not possessed by their individual con- stituents ; gold is too soft for ordinary use, but if alloyed with copper, or silver, or platinum, etc., becomes qualified for certain practical purposes. Copper is too soft and tough to work in a lathe, but if fused with one-half its weight of zinc, it forms the hard, tenacious alloy, known as brass. Copper and tin in different relative proportions give us the useful alloys, bronze, bell metal, specu- ulum metal, etc. German silver consists of 100 parts copper, 40 of nickel, and 16 of zinc. Type metal is an alloy of antimony and lead. Alloys of mercury with other metals are named am.algams.

The melting point of an alloy is generally lower than the mean melting [)oint of its constituents. For instance, tin melts at 235° (455 F.) ; bismuth, melts at 2(34° (507 F.) ; lead melts at 320° (608 F.).

An alloy of 1 part of* tin, 2 of lead, and 2 of bis- muth will melt as low as 93° C (200 F.). Such an alloy is useful in attaching teeth, by dovetail, to old celluloid and rubber plates, and maybe packed in with a warm burnisher.

The metals differ greatly in specific gravity, rang- ing from potassium, sodium and lithium, which are

128 Inorganic Chemistry.

lighter than water, to platinum, iridium and os- mium, which are more than 21 times heavier than water.

They differ also in tenacity^ or the power of re- sisting tension. The order of tenacity among those metals susce[)tible of being easily drawn into wire is determined by observing the weights required to break wires of the same size, and is as follows : Iron, copper, platinum, silver, gold, zinc, tin, and lead.

Malleability, or power of extension under the hammer, or between the rollers of a flatting mill, is possessed in a high degree by gold, silver, cop- per, tin, platinum, lead, and iron.

The fusing points of metals vary greatly, ranging from mercury, which melts at — 39°, to platinum, which requires the heat of the oxy-hydrogen flame. A certain uniformity of color is presented by the metals, except copper, which is red, and gold, which is yellow ; all the other metals (leaving out the faintly pinkish tint of bismuth, and the yellowish tinge of calcium and strontium), are included be- tween the white of silver and the blui,sh gray of lead.

The several metals are classified into groups, ac- cording to certain chemical and physical proper- ties possessed by them ; those of the same group

Metallic Elements. 129

generally, also, possess the same valency. Brief allusion to some of the characteristics of two or three groups will suffice. For example:

The metals of the alkalies., viz., K, IS'a, Hb, Cs, and Li, are soft, easily melted, volatile at a higher temperature, will decompose hot or cold water through their love for oxygen. Their oxides are strongly basic, and are very soluble in water, form- ing exceedingly caustic and alkaline hydroxides Their carbonates are soluble in water, and being monads^ they each form only one chloride (K CI).

The metals of the alkaline earths^ Ca, Ba, and Sr, form oxides less soluble in water than those of the preceding group, but exhibiting, though in less de- gree, similar basic, caustic and alkaline propor- ties. Their carbonates are insoluble in water; they each form but one chloride, which, as they are dyads, is a dichloride (CaClg).

The metals of the earths, erbium, yttrium, didy- mium, etc., form oxides that are not soluble in water. The metals of this group occur only in a few rare minerals.

All metals form binary compounds with chlo- rine. The monochlorides and dichlorides of the metals, excei)ting silver chloride (AgCl), and mer- curous chloride (Hg2Cl2), are soluble in water. Metallic chlorides unite with certain oxides, form-

130 Inorganic Chemistry.

ing oxyehloridfs, and with organic bases, also, such as aniline and the ptomaines.

]!^early all metals unite with Br and I. Most metallic bromides and iodides are soluble in water; they closely resemble, in many instances, the cor- responding chlorides.

Oxygen unites with all the metals, with many of them in several proportions. Some metallic oxides, as K2O and CaO, do not decompose by heat alone; others, as AU2O3, Ag2 0, Pt02 and HgO, lose their oxygen by a low red heat. Most of them suffer re- duction by hydrogen, aided by a more or less high temperature, while carbon, at a red or white heat, completely reduces all to the metallic state.

Potassium. 131

CHAPTER Y.

POTASSIUM.

Symbol, At. Wt. Sp. Gr. Yal.ency,

K. (Approx.) 0.87.50. I.

39.

L^TASSIUM occurs abundantly in nature, always however in combination. It is an essential constit- uent of animal and laud vegetable bodies, and is found largely in many minerals. The ashes of land plants, are especially rich in potassium, hence its name.

Potassium was discovered by Davy in 1807 by electrolysis ; it is now obtained by heating the car- bonate with charcoal, e, g.

KCO3 -f- 2C = 3C0 + 2K

The metal, being volatile, distills over, is passed through naphtha, and condensed to proper form. It melts at 62.5° (14'4.5F) ; it is soft at common tem- peratures, and can be easily cut with a knife, pre- senting a brilliant white surface, which soon tarnishes, owing to the strong liking it has for oxygen. For this reason, it soon loses its identity when exposed to the air, and must be preserved in some liquid, destitute of oxygen, such as naphtha.

132 Inorganic Chemistry.

Thrown on water, it floats; at the same time caus- ing equivalent decomposition of that liquid. H-O-II -f K = K-0— H + H

So great is the chemical energy of this reaction, that the hydrogen as it escapes from the water, is set on fire.

Potassium forms several oxides ; the normal oxide, K2O, being obtained by direct oxidation, or by ac- tion of potassium on the hydrate.

Potassium Hydrate (hydroxide) KOH, commonly called caustic potash, is generally prepared by ac- tion of calcium hydrate fmilk of lime) on potassium carbonate.

Ca(H0)2 + K2CO3 = CaCOg + 2K0H

Calcium Potassium Calcium Potassium

Hydrate. Carbonate. Carbonate. Hydrate.

Potassium hydrate is a white, soluble, deliques- cent solid ; strongly alkaline, caustic and poison- ous.

Potassium carbonate, K2CO3, is the familiar sub- stance, potash. It is prepared from wood ashes, and by various other chemical processes ; when re- fined it is known as pearlash ; it has a strong alka- line reaction, is soluble in water, but insoluble in alcohol ; is used in preparing other potassium com- pounds, and for the making of glass and soft soap. By treatment with carbonic acid it produces the " bicarbonate."

Potassium.. 133

K.COs + H2CO3 = 2KHCO3

Carbonic Potassium

Acid. Bicarbonate.

The bicarbonate is also called the hydrogen car- bonate, and acid carbonate, although it is mildly alkaline.

Potassium chloride, KCl, obtained principally from sea water, is a colorless solid, soluble in water, and

is found in the juices of animal bodies.

Potassium Iodide, KI, is prepared by the action of iodine on potassium hydrate. It occurs in color- less cubical crystals, of sp. gr. 3, soluble in water and alcohol.

Potassium Bromide, KBr, is similar in appearance to the iodide, and is obtained by an analogous process.

Potassium Chlorate, KCIO3, is prepared by passing chlorine through a solution of the carbonate; or through a solution of the chloride, containing milk of lime. KCl-H3Ca(OH)2+6Cl=3CaCl2H-3H20+KC103

It is a colorless crystalline anhydrous solid, solu- ble in 20 pju'ts of cold water. When heated it gives up all of its oxygen, and when mixed with combustible matter, like sulphur, tannin, etc., it becomes explosive. With phosphorus it is largely employed in the making of instantanoous-Jight matches.

134 Inorganic Chemistry.

Potassium nitrate^ KlJ^Og, commonly known as saltpeter and niter, occurs naturally in the soil, from oxidation of ammonia in the presence of po- tassium compounds.

Potassium nitrate crystallizes in anhydrous six- sided prisms, soluble in 7 parts of water.

It is prepared in large quantity by reaction be- tween Chili saltpeter and crude potassium chloride.

Na:^03 + KCl = NaCl + KNO3 When heated in the presence of combustibles, it gives up its oxygen ; hence it is used in the manu- facture of gunpowder and in nearly all pyrotech- nic compositions, which accordingly burn inde- pendently of atmospheric oxygen. Average gun- powder is a mechanical mixture of niter, charcoal and sulphur, in the following proportions:

KN03	75
0	15
s	10

100

The force of the explosion of gunpowuer is due to sudden formation of gases and their immediate expansion by the heat. All of the powder is at once vaporized, and although the chemical reaction is really complicated, it may be ap [proximately represented by the following equation :

2KKO3 + 3C + S = K^S + 3002- + 21S"

Potassium. 135

Potassium Permanganate, K2Mn20g, is prepared from mixed aqueous solutions of potassium chlo- rate and manganese dioxide, by evaporating to dryness, and gently heating. It occurs in dark purple crystals, of a pleasant, astringent taste ; dis- solves easily in water, conferring a deep lilac color, which may be decolorized by Fowler's solution.

It is a powerful oxidizing agent, used in chem- ical analysis, and for destroying putrid matter.

Potassium forms a great many other compounds, such as the perchlorate, bromate, iodate, sulphide and sulphate, phosphates, borates, silicates, etc., their consideration, however, in this connection is unnecessary.

Materia Medica. — Some of the potassium salts produce active local eifects. The hydroxide is one of the most penetrating caustics, owing to its removal of water from the tissues, and saponify- ing the fats.

The disadvantage of its penetrating qualities, is somewhat overcome by combination with lime ; its use as a free caustic has been practically aban- doned.

The permanganate, on account of its giving up active oxygen to organic matter, is an excellent disinfectant in fetid odors and as a gargle in gan-

136 Inorganic Chemistry.

grenous conditions of the mouth and throat. Dose, 0.06 Gm. (gr.j).

The nitrate and chlorate are employed in solution, or powder, on inflammatory mucous membrane of the mouth and throat. The latter drug especially is effective in mercurial stomatitis.

When taken internally the potassium salts, as a rule, weaken the normal functions of the brain, including the co-ordination of motion, reduce the reflex sensibility of the spinal cord and nervous system generally. They also cause a lowering of the heart's action, of respiratory movement and of temperature. The secretion of saliva is lessened, and of the gastric juice increased. It may be well to mention here that alkalies, in moderate doses, decrease the secreting power of those glands which normally secrete an alkaline fluid, like the parotid glands, and increase the power of glands which secrete an acid, like those of the stomach. Acids have precisely the opposite eflect.

Most of the salts of potassium are diuretic and slightly purgative.

The chlorate, in doses of 0.50 Gm. (gr.viii) is indi- cated in mercurial salivation, aphtha, and ordinary tonsillar inflammation, suggesting at the same time a local exhibition of a strong solution as a wa&h or gargle, or in the form of trochisci.

Potassium. 137

The Bromide is reputable as an antispasmodic and nervine sedative, and is given in epilepsy, de- lirium tremens, convulsive seizures of children due to dentition, laryngismus stridulus, acute mania and loss of sleep.

The Iodide, unlike the chlorate, increases the se- cretion of saliva, sometimes to the point known as iodism.

Doses: Pot. chlorate, 0.65 Gm. (gr.x).

Pot. nitrate, 0.65 Gra.

Pot. bromide, ] a r.?- onn r> r \

Pot. iodide. I 0-6O-200 Gm. (gr.x-xxx).

R. Potassii chloratis, 8 Gm. (^ii). Aqua, 250.00 fGm. (f^viij).

M. S. A gargle in stomatitis.

12

138 Inorganic Chemistry,

CHAPTER VI.

SODIUM.

Symbol, At. Wt. Sp. Gr. Valency,

:N'a. 23. 0.97. I.

Sodium was discovered by Davy in 1807 by elec- trolytic decomposition of soda. It is a very abun- dant element, existing in enormous quantities as a chloride; in sea water, as rock salt, in salt lakes and mineral springs, in marine plants, and as a necessary constituent of animal juices.

Large deposits of the nitrate. Chili saltpeter, car- bonate, and borate, occur in nature, also sodium and aluminum fluoride, and sodium silicates.

Sodium is a white soft metal; it melts at 95.5° (204 F). It decomposes water, but not with as much energy as does potassium; if the water, how- ever, be warmed, or thickened with starch, the es- caping hydrogen will ignite. The reaction corre- sponds to that of potassium.

Sodium chloride, I^aCl, common salt, is obtained by mining rock salt, and by evaporating salt water. It is a transparent, colorless, crystalline, anhydrous

Sodium. 139

solid of sp. gr. 2.15, of an agreeable taste, slightly deliquescent, and dissolves in 3 parts of water.

There are two oxides of sodium, !N'a2 0, and Na^O.^, of no practical importance.

Sodium hydrate, or hydroxide, NaOH, caustic soda, is formed and held in solution when sodium is thrown into water; it is, however, practically pre- pared from the carbonate, in the same way that caustic potash is obtained. It is strongly- alkaline, but not so active a caustic as the potassium salt. Its use in commerce is for refining fats and oils, and in making hard soaps.

Sodium Carbonate, ^2^,^00^, is manufactured by several processes, but is mainly obtained from the chloride, by the " Leblanc process," the de- scription of which is unnecessary. It crystallizes with 10 molecules of water, Na2CO3,10H2O, and is the "sal soda" of the laundries. When devoid of water, or dry carbonate, it is used in very larg^e quantities in the making of glass and soap.

Sodium carbonate is strongly alkaline, owing to the strong base and the weak acid, in its compo- sition. If it be subjected to the direct action of carbonic acid, the ''' bicarbonate,'^ N'a HCO3, a mild alkali will be produced. This is the cooking soda of the kitchen, is an ingredient of all baking

140 Inorganic Chemistry.

powders, and of many effervescent drinks, and is also used in medicine.

Sodium Borate Na20,2B203, IOH2O borax, occurs native, in colorless crystals, slightly effervescent, and mildly alkaline ; soluble in water and glycer- ine, bat not in alcohol. It is used in the arts as a flux in melting, soldering, and welding certain metals. When heated, it swells up, losing its water of crystallization, and then subsides as a vitreous mass (borax glass), which is removed from the surface of the soldered metal, by dilute sul- phuric acid. A solution of borax (or solutions of sodium carbonate, or of alum) will render dried plaster casts comparatively hard.

Other compounds of sodium are numerous, and some of them important; they resemble for the most part, the corresponding compounds of potas- sium.

Materia Medica. Sodium Chloride is a flesh preserver, and may be considered a good prototype of antiseptics in general. .

Laharraques Solution, liquor sodse chloratse, solu- tion of chlorinated soda, [N'aCl, NaClO, analogous to common bleaching powder. Locally, it acts as a disinfectant, destroying maladorous and infectious matter, by reason of the free chlorine and free oxy- gen it evolves, in the presence of acids (carbonic

Sodium. 141

acid of the air) ; for the same chemical reason it is a good bleacliing agent, if combined with powdered ahim.

The bicarbonate is used locally as an antacid, and when mixed with water, as an application to burns and scalds.

Borax is a mild antacid, antiseptic, refrigerent, and detergent. It is a useful ingredient of mouth washes, or gargles, in inflammation of mouth or throat, combined with sweetening correctives, as honey, glycerine, etc.

When internally administered the sodium salts have not the depressing influence on the system possessed by those of potassium.

Dose. Sodii Bicarbonas, ) i aa /^ /- n

bodn rJiboras, j \fe ^

B. Sodii Boras, 4.00 Gm. (^i). Mellis. Aqua aa, 30.00 fGm. (f^i).

M. S. Use as a detergent.

The other metals of the alkalies, viz., lithium, rubidium, and caesium, are also monads, and are comparatively rare. They are highly oxidizable ; ciesium being the most highly electro-positive of all elements; they decompose water, setting hy- drogen free, and form alkaline caustic hydroxides.

Ammonium, ^H^, is a hypothetical, univalent,

142 Inorgnnic Chemistry,

electro-positive, compound radical. Although it has not been isolated, it acts like metals in the formation of various salts, being developed in re- actions between ammonia, NHg, and other bodies containing hydrogen. Thus, ammonia and nitric acid, HNO3, unite with each other, without setting any hydrogen free ; the hydrogen of the acid, probably joins itself most intimately to thelTHg, to form the radical KH4, which then, like an atom of potassium, unites with the electro-negative radical,

NO3. ■

NH3 + HNO3 = FH^.NOj

Ammonia. Nitric Acid. Ammonium

Nitrate.

Ammonium salts are numerous, and resemble in many respects the corresponding salts of the alkali metals. The hydroxide, NH^ OH, is an alkaline caustic, which, when dilute, gives up free ammonia, and is employed by inhalation as a stimulant in ordinary syncope, and in excessive anaesthetic narcosis.

The Chloride, J^H^Cl, the ''sal ammoniac" of commerce, is used as a flux in refining gold ; and as a local stimulant to indolent ulcers. The car- bonate, which has a rather complicated formula, is known as " sal volatile," and is the principal sub- stance in " smelling salts."

Inorganic Chemistry. 143

CHAPTER VII.

CALCIUM, ETC.

Symbol, At. Wt. Sp. Gr. Valency,

Ca. 40. 1.50. II.

Calcium is not found free in nature, but exists abundantly in combination. As carbonate it occurs in limestone, marble, chalk, coral, marl, oyster shells, Iceland spar, the stalactites and stalagmites of certain caves, and in bones and teeth; as a fluoride, sulphate, phosphate, and in many silicates.

The metal itself is brilliant, slightly yellow, some- what hard, very malleable and ductile, oxidizes slowly in the air, decomposes water, and when heated burns with an extremely bright light. It may be obtained by heating the iodide with sodium, but singly it is of no practical use.

Calcium forms but one chloride, CaCl2, which occurs as a waste product in many processes.

Calcium oxide, CaO, lime, is always prepared on a large scale by heating the carbonate, as lime- stone, in a lime kiln. The carbonate being com- posed of calcium oxide and carbon dioxide, the latter is driven off by the heat, as will be easily un- derstood by the equation.

144 Inorganic Chemistry.

CaO, CO2 + Heat = CaO + CO2

Calcium Calcium

Carbonate Oxide

(Lime)

Lime is a hard, infusible, white solid. When slaked with water, which union develops great heat. Calcium hydroxide, Ca(H0)2, is formed a white, bulky powder, which, in an excess of water dis- solves, resulting in a clear alkaline liquid, known as lime water. Lime water readily absorbs CO^ from the air, as does also milk of lime (whitewash), and the lime of mortars and cements. It is to this fact that the hardening of cements, made largely from lime is due; the absorption of the CO^, forming a quasi limestone, a true carbonate. When sand is present, calcium silicate is also formed.

Calcium Carbonate exists in so many forms in nature, as already noticed, that its description seems superfluous. It is soluble in water contain- ing carbonic acid, as nearly all natural waters do, therefore such waters, in limestone regions, are hard. They may be rendered soft by boiling, which drives off the carbonic acid; or by an al- kali, like ammonia, which takes up the acid, whereby the lime salts are precipitated.

It is probably owing to similar reactions that occasion the deposition of tartar on the teeth.

The fluids of the parotid, and submaxillary

Calcium, etc. 145

glands, holding lime salts in solution, by aid of the carbonic acid present, upon their egress into the moutli, meet with free alkalies, the results of putrefaction change, which take up the carbonic acid; the removal of the acid, thus, deprives the saliva (water) of its ability to hold the lime salts in solution, and they are precipitated.

Calcium sulphate occnrs in nature as alabaster and selenite and en masse as gypsum, CaS04, 2H2O. When heated sufficiently, gypsum loses its water of crystallization, and becomes plaster of Paris; this plaster readily takes up water again, and ''sets" to a hard solid. It is used in taking im- pressions, and in forming models of the parts to be supplied with artificial dentures; and also for making molds and casts of various kinds.

Calcium Phosphate, Cag (P04)2, bone phosphate, is found in natural deposits in certain portions of South Carolina, Florida, and the islands of the Carribean sea, sup{)Osed to be the remains of vast numbers of marine animals that were gradually imprisoned in the now extinct salt water lagoons, by land appearing between them and the ocean. It is the principal constituent of bones and teeth; it is found also in the other tissues, and in calculi. Prepared as precipitated calcium phosphate, it is a white, tasteless and odorless powder, insoluble in 13

146 Inorganic Chemistry.

water and alcohol, but freely soluble in even weak acids.

Calcium Fluoride^ CaF2, iluor spar, constitutes about two per cent, of human bone and enamel.

Chlorinated Lime, CaCl2 0, bleaching powder, sometimes improperly called, chloride of lime, is formed by action of chlorine on slaked lime; oc- curs as a gray white powder, or in lumps slightly moist, emitting a faint chlorine odor, soluble in water, and decomposed by the carbonic acid of the air (likewise by other dilute acids) into free chlo- rine, and other bodies. By the influence of the nascent chlorine on the hydrogen present in the moisture, active oxygen results. The preparation, therefore, is an excellent disinfectant and bleaching agent.

Oxygen is set free en masse, by acting on a so- lution of the powder with a solution of nitrate of cobalt.

For bleaching teeth, the dry powder may be in- corporated with tartaric acid, introduced into the cavity slightly moistened, and covered with gutta percha.

Materia Medica. Some of the lime prepara- tions used locally are sedative and soothing, as linimentum calcis (lime water and linseed oil), ap- plied to burns.

Caiciumy Etc. l47

Prepared chalk is probably the basis of all tooth powders; it acts as an antacid and astringent. When taken internally, lime and chalk act in the same way.

The phosphate has been recommended, although its efficacy is doubtful, as a food supply, whenever the structural pabulum in growing bones of infancy and chilehood is deficient.

Doses. Liquor Calcis, 8.00 f Gm. (fsij).

Creta Prseparata, 1.00 Gm. (gr.xv).

Calcii Phosphas. Prsecipitata, 1.50 Gm. (gr. xx).

B. Calcii phos. prsecipit, 4.00 Gm. (51). Mistura Cretse, 125.00 fGm. (fgiv).

M. S. Give a teaspoonful to child at meals.

The two other elements of the calcium group, strontium and barium, are comparatively rare and unimportant, strontium nitrate Sr(N03)^ is used in making "red fire," barium nitrate Ba(N03)2 in making "green fire." Barium salts are used as a test for suli)huric acid, and vice versa. Barium sulphate is known as " heavy spar," and when ground is used as a pigment.

There are two oxides of barium, and these are easily changed, the one into the other. BaO heated in air, is converted into Ba02. This dioxide readily gives up 0, as in the manufacture of hydrogen di- oxide, already alluded to.

148 Inorganic Chemistry.

CHAPTER YIII.

METALS OF THE EARTHS, AND SILVER.

The metals of the earths — yttrium, erbium, samarium cerium, etc. — are quite numerous, but are found only in a few rare minerals, principally as silicates. They, and nearly all their com- pounds, are mere chemical curiosities, except cerium oxalate, Ce^ (^2^4)3' which is used in medicine.

SILVER.

Symbol, At. Wt. Sp. Gr. Valency, Ag. 108. 10.5. i-in.

Silver has been known from the earliest times. It is found in various countries, in the metallic state, but principally in combination, as chloride, iodide-, bromide, sulphide and telluride. The vari- ous elaborate methods employed for extracting sil- ver from its ores are interesting from a commercial chemical point of view, but need not be considered here.

It is a brilliant white metal, malleable, and duc- tile, and is the best conductor of heat and electric-

Metals of the Earths , and Silver. 149

ity. It melts at about 1000° (1850 F), does not tar- nish in pure iiir, although traces of 11.^ S affect it, as it sulphidizes easily; it is also readily acted on by CI and P; hydrochloric and sulphuric acids at- tack it with difficulty, but nitric acid, even quite dilute, rapidly dissolves it.

Ag. + HXO3 = Ag^O, + H.

Silver Nitrate AgNOg, lunar caustic, is obtained according to the above equation; by evaporating the solution, it appears in the form of colorless, transparent, anhydrous crystals, soluble in water and alcohol. When melted and cast into proper shape, it is known as lunar caustic.

Silver nitrate is employed in photography, in the making of hair dyes, inglelible ink, etc., on account of its turning dark by the influence of light, when in contact with organic matter, probably due to the deposition of argentous oxide.

Silver Chloride, AgCl, is precipitated whenever a soluble chloride (common salt, etc.), is added to a solution of silver nitrate. It is a white curdy sub- stance, insoluble in water and nitric acid, but dis- solves easily in a([ue()us solutions of ammonia and potassium cyanide. When heated, it fuses, and on cooling, assumes a horny consistency, hence the name of the mineral horn silver.

150 Inorganic Chemistry.

Silver chloride decomposes in the light, rapidly, when in contact with organic matter; also when heated with sodium carbonate, or placed in dilute sulphuric acid with zinc or iron. In the latter pro- cess, the nascent hydrogen removes the chlorine, leaving the silver in the form of a spongy mass.

There is another chloride of silver of uncertain constitution; and three oxides. The normal oxide, Ag^O, a strong base, which yields salts isomor- phous with those of the metals of the alkalies.

Materia Medica. The nitrate is the only silver compound that need be noticed in this connection. It is employed almost exclusively as a local agent, and possesses decided caustic properties, by reason of its coagulating action on albumen ; by this means, a protecting pellicle is soon formed, which prevents the caustic action from extending deeply. It is used to induce healthy granulations in ulcers and wounds, and when properly diluted, is one of the most efficacious applications to every variety of inflammation of the mucous membrane.

Applied in substance to sensitive abraided, or denuded, or even decayed surfaces of teeth, it re- lieves the tenderness and arrests the process of de- cay. On account of the permanent darkening of the tooth substance to which it is applied, especial discretion should be observed in its use.

Silver. 151

Dose. Silver Nitrate, 0.01 Gra. (gr. -J). Antidote, common salt.

B. Argenti Nitras, 0.10 Gm. (gr. jss). Aqua Dest., 30.00 fGm. (f^i).

M. S. Injection in diseased antrum.

152 Inorganic Cheynistry.

CHAPTER IX.

COPPER, MERCURY.

Symbol, At. "Wt. Sp. Gr. Valency, Cu. 63. 8.95. 11.

Copper is one of the ancient metals and is still of great value in the arts. It is found in nature both native and in combination, as oxide, carbon- ate, and sulphide, and with iron sulphide as " cop- per pyrites."

Copper has a familiar yellowish-red color ; is malleable and ductile and tenacious; is one of the best conductors of electricity and heat ; melts at about 1090 (1994-F), is not acted on by dry air, but in moist air it tarnishes with a green crust, consisting principally of the carbonate. When heated, scales of black cupric oxide form on its surface. Chlorine, sulphur, and nitric acid attack it readily; in the lalter case, setting free fumes ot 1^^2 02. It also forms salts wnth dilute acetic acid and hot sulphuric acid, and slowly, with dilute hydrochloric and sulphuric and carbonic acids, al- kalies and saline solutions. All sol able salts of copper are poisons.

Copper, 153

Certain alloys of copper have been mentioned. Its compounds are numerous, but few of them need be considered here.

Copper forms two series of salts, the eupric and cuprous.

Cupric chloride^ CuClj, obtained by dissolving eupric oxide in hydrochloric acid, and by direct ac- tion of chlorine. It makes, with water, a green so- lution which, on evaporation, deposits green crys- tals containing water, CuClj, 2H2O3. When heated it loses all its water of crystallization, and half its chlorine, and is converted into cuprous chloride, CU2CI2, a white fusible substance, slightly soluble and prone to oxidation. Both chlorides form double salts, with the chlorides of the alkali metals.

Cupric oxide, CuO, or black oxide of copper, may be prepared by heating copper in air, or by calcin- ing the nitrate, carbonate, or hydrate. It unites with most acids, forming cupric salts. With [ihosphoric acid it forms a hard, tenacious, insol- uble, black mass, which combination has been introduced by Dr. W. B. Ames, as a tilling imate- rial in posterior teeth, for setting crowns, etc. The mineral libethenite is IlCu^POr.

Cuprous oxide CU2O, red oxide of copper, is like

154 Inorganic Chemistry.

the other cuprous compounds, important only as conferring a beautiful ruby red color to glass.

Cupric sulphate, CuSo4,5H2 0, blue vitriol, prepared by dissolving cupric oxide in sulphuric acid, oc- curs in large blue crystals, and is extensively em- ployed in electro-metallurgy, telegraph batteries, calico printing, the making of Paris green, etc.

Materia Medica. — Copper sulphate in substance is an excellent application to fungous conditions of the gums, as it acts as an astringent and lessens the local blood supply, and is a mild caustic.

Internally in large doses it acts as an emetic, in small doses as a tonic.

Dose. (Emetic), 0.20 Gm. (gr.iij). (Tonic), 0.02 Gm. (gr. J).

MERCURY.

Symbol, At. Wt. Sp. Gr. Valency, Hg. 200. 13.59. 11.

Mercury, quicksilver, the argentum vivum, of the ancients, is found native, but principally as a sul- phide, cinnabar, extensively mined in California, Mexico, and Peru, and portions of the old world. The sulphide is reduced by roasting with lime, the metal volatilizes and is condensed in suitable chambers.

Mercury is a brilliant silver- white liquid. At

Mercury. 155

40°C (and F) it solidifies to a tin-like malleable mass of specific gravity 14.19. It is slightly volatile at 15° (60-F) and boils at 357 (666-F) ; yields a vapor of density of 100; the molecule of mercury, there- fore, consists of one atom. Mercury is unaltered hy the atmosphere, but near its boiling point it slowly absorbs oxygen, passing into the red oxide, IlgO. Chlorine and sulphur unite directly with mercury. Boiling strong sulphuric, and even di- lute nitric acid attack it easily, but it is unaffected by hydrochloric and cold dilute sulphuric acids.

Mercury is used in the making of many physical instruments, as thermometers, barometers, etc., and in extracting gold and silver from their ores. Its alloys are called amalgams. Of these, only those used for filling careous teeth are of special interest to us. Copper amalgam is produced by various processes, among the best, perhaps, being by electrolysis of copper sulphate in the presence of mercury. It is a hard amalgam when properly made; does not change in bulk or shape in set- ting, and acts as a germicide and antiseptic. It, however, dissolves in weak acids, and the decidedly black copper oxide and sulphide which, together, form on the surface, are probably converted into copper sulphate, which we know to be freely solu- ble. Both of these facts combined, or either one

156 Inorganic Chemistry.

singly, can explain satisfactorily the wasting that 80 often takes place in copper amalgam fillings.

Mercury forms with many other metals, amal- gams of either continued pasty, or hard consist- ency, according to the metal used. An amalgam of an alloy of about 50 parts silver and 40 parts tin, containing also small additions of copper, gold, zinc, platinum, palladium, antimony, and cadmium, sin- gly or otherwise, seems to produce the best results in dental practice. The blackening of amalgam fillings is due to the formation of metallic sulphides, and is considered a not unmixed evil ; the more em- phatically blacky the better the preserving qualities.

Mercuric chloride, HgCl2, bichloride of mercury, corrosive chloride, corrosive sublimate, etc., is usu- ally prepared by subliming a mixture of sodium chloride and mercuric sulphate.

2XaCl + HgSO^ = Na^SO^ + HgCl2

Sodium Mercuric Sodium Mercuric

Chloride. Sulphate. Sulphate. Chloride.

Mercuric chloride is a semi-transparent crystal- line heavy solid, of an acid metallic taste, and acid reaction. It is soluble in 16 parts of cold, and 2 parts of hot water, 3 of ether, and 2 of alcohol, and is a strong corrosive poison.

Mercurous chloride, Hg2-Cl2, proto-chloride of mercury, mild chloride of mercury, submuriate, calomel, etc. Calomel occurs native, in tetragonal

Mercury. 157

crystals, but is commercially prepared by sublim- ing a mixture of sodium chloride, mercuric sul- phate and mercury. 2NaCl + HgSO^ + Hg == Na,S04 + Hg2Cl,

Mercurous Chloride.

A heavy white, iine powder condenses, insoluble in water, and alcohol, tasteless, and decomposes slowly in sunlight into freeHg andHgCl^.

31ercuric oxide, HgO, occurs in red scales, when mercury is heated in air, commonly as red precipi- tate. It forms with acids, mercuric salts.

JflercuroiLS oxide, Hg^O, a black powder, produced by action of alkali-hydrates on calomel. With acids it forms mercurous salts. There are two iodides of mercury analagous to the chlorides.

Mercuric sulphide, HgS, has already been alluded to as the mineral cinnabar. When made synthet- ically it is known as tlie brilliant red pigment, vermilion.

Mercurous sulphide Hg.^S, is a black powder, known as ethiopes mineral.

f CI Mercuric chloramide, ITg -| ^^ is known as

white precipitate.

Materia Medica. — Mercurial preparations are favorite local remedies in certain skin diseases and syphilitic ulcerations, in virtue of their germicidal and antiseptic properties. The practice of steril-

158 Inorganic Chemistry.

izing instruments in hot solutions of mercuric chlo- ride is effective, although the efficacy of a cold solution might be questioned. A cold aqueous so- lution of this drug has been a favorite germicide in sterilizing root canals of teeth, preparatory to fining. It forms, with albuminous matter, a coag ulum of only temporary existence, consequently, the duration of asepsis, secured by it, is limited • and unless the disease germs, held in the coagulum, are immediately killed by it— a wished-for consum- mation, the occurrence of which, many deny — its virtues as a germicide and antiseptic woultT be active only during the period of coagulation ; and if more or less organized matter remain in the ca- nals, at the time of filling, a condition that unfor- tunately sometimes obtains, its coagulation by cor- sosive sublimate, would therefore be of doubtful permanent efficiency. The salts of mercury, nev- ertheless, appear to possess especial destructive power over the germs of syphilis at least, and a wash of corrosive sublimate solution, used before operating in the mouth of a syphilitic patient, would sterilize the part for the time being.

Taken internally, the salts of mercury if pushed to the limit, occasion nervous debility, and cause anaemia by destroying the red corpuscles. They increase the secretion of saliva, mercurial salivation

31ercury. 159

sometimes following their use. Antidote to mer- curic chloride — emesis, albumen, white of ^gg, milk, flour.

Dose. Mercuric Chloride, 0.004 Gm. (gv. yL). Mercurous Chloride, 0.30 Gm. (gr. v).

R. Hydrarg Chlor. Corrosiv. 0.10 Gm. (gr.jss). Acidi Hydrochlorici Dih, q. s. ad. solve. Mellis Depurati, 15.00 fGm. (f^ss). Aqua Dest., q. s. 150 fGm. (f 3 v).

M. S. To be used as a wash, or gargle, in syphiUtic ulceration of mouth and throat.

160 Inorganic Chemistry.

CHAPTER X.

ZINC, ETC.

Symbol, At. Wt. Sp. Gr. Valency, Zn. 65. 7. 11.

The chief ores of zinc are the sulphide, carbon-

*

ate. oxide, and silicate. These are calcined in air, producing zinc oxide; the latter is then distilled with charcoal (C), which takes up the oxygen, the zinc vapor condensing in suitable vessels.

2ZnO + C := CO2 + 2Zn Zinc is a bluish white metal. At ordinary temper- atures it is hard and brittle ; at about 150° (300°F), it becomes quite malleable ; at 200° (392° F), it again becomes brittle, and may be broken up in a mor- tar; at 412° (773°F), it melts, and at about 1000° (1832°F), if air be present, it volatilizes and burns with a splendid greenish light, forming its only oxide, ZnO. Zinc is slowly oxidized in moist air, and is acted on easily by dilute acids, by alkali- hydrates, and by the halogens. It is used largely as a protecting coat for sheet iron; it forms the posi- tive element of galvanic batteries, in making dies for swaging dental plates, as a constituent for some

Zinc. 161

amalgams, and of other highly valuable alloys, as brass, etc.

Zinc chloride, ZnCl2, is made by direct action of chlorine upon zinc, or by dissolving granulated zinc, or zinc carbonate in hydrochloric acid, purifying by solution of chlorine and zinc carbonate, and evaporating the solution to dryness. It occurs as 11 grayish-white translucent, cr^^stalline mass, deli- quescent, and very soluble in water, and in alcohol, and ether. Liquor zinci chloridi, is the official prepa- ration, and contains 14.00 Gm. (5 ijjss) of zinc chloride to 30.00 f Gm. (fSi) of water. The solution for oxy- chloride cement should have a sp. gr. of about 1.50.

Aside from its use in surgery, zinc chloride is em- ployed as a chemical dehydrating agent; that is, it will not only take away water, but the elements of water from organic compounds (and from albumin- ous organized structure, which probably explains its action as a caustic). It is also used as a solder- ing fluid.

Zinc oxide, ZnO, is the product of the combus- tion of zinc in air; it is used extensively as a pig- ment. The pharmaceutical preparation is obtained by subjecting pure precipitated zinc carbonate to a red heat, until all the water and CO.^ are driven ofl'. It should appear as a white, smooth, impalpable powder. It is tasteless, and insoluble in water, but 14

162 Inorganic Chemistry.

is acted upon by the common dilute acids. It is the basis of the various zinc cement preparations, mixed with variable quantities of silica, borax, pul- verized glass, etc

The liquid for the oxychloride has already been described; that for the oxyphosphate consists of tri-basic phosphoric acid, II3PO4, prepared by dis- solving pure glacial phosphoric acid, HPO3, in warm water and evaporating to a syrupy consis- tency.

In preparing the filling, the powder should be added to the liquid slowly, and mixed thoroughly, until the magma has a stiff, tenacious feel, then in- serted in place, and kept dry for 20 or 30 minutes. The result will be a hard coherent filling, of rea- sonably lasting qualities, depending more than less, on its position in the tooth. Chemical union be- tween "the acid, and the zinc oxide of the powder, undoubtedly takes place; the other ingredients of the powder being held mechanically; but this union can be overcome by either acids or alkalies. It is known that these fillings give way rapidly at the cervical wall, if under, or near the gum mar- gin ; such positions are most favorable to develop- ment of alkalies, by putrefaction (ammonia, and its derivatives, the amines, a^iiides, ptomaines, etc.), and also somewhat to acid fermentation. The alkali

Zinc. 163

will appropriate its equivalent of the phosphoric acid, the cement losing its integrity to that extent; while the acid stage of fermentation, if such should occur, would tend to destroy the cement, by at- tracting the oxide of zinc. In such a situation the oxyphosphate fillings are, evidently, ^'between the devil and the blue sea."

Zinc sulphatCy ZnS047Il20, white vitriol, obtained by the action of sulphuric acid on granulated zinc, occurs in small, colorless, efflorescent crystals, solu- ble in water, insoluble in alcohol, and of a metallic styptic taste.

Materia Medica. Zinc chloride is a powerful caustic, owing to its dehydrating qualities. It is employed in substance, or strong solution, for treat- tnent of cancerous and other forms of ulceration. As an obtunding agent to sensitive dentine, it is affective, although superficial ; but on account of the pain immediately following, and the danger to the vitality of the pulp involved, the practice of applying it as a dentinal obtundant, has been nearly abandoned. In solution, it is successfully employed as an injection in chronic alveolar abscess, in an- trum disease, and in the gum pockets of alveolar pyorrhoea.

The sulphate acts locally as an astringent and stimulant.

164 Inorganic Chemistry.

Internally, the sulphate is tonic, antisposmodic and astringent. In large doses it is the favorite direct emetic.

Dose. Zinc Chloride 0.03 Gm. (gr.ss.)

ZiDc Sulphate 0.06-0.30 Gm. (gr. j-v.)

As au emetic — Zinc Sulphate 0.65 Gm. (gr. x.)

Antidote, Sodium bicarbonate.

B. Zinci Chloridi 0.06 Gm. (gr.j). Aqua Rosse 30.00 fGm. (fgi.)

M. S. A good injection, Antrum, etc. MAGNESIUM.

Symbol. At. Wt. Sp. Gr. Valency. Mg. 24. 1.75. II.

Magnesium is an abundant element, but is always found in nature in combination. The double car- bonate of magnesium and calcium MgCa2C03 is known as dolomite or mountain limestone, of which whole mountain ranges are formed. The metal also occurs in the single corbonate, the sulphate, h^^drate, fluo-phosphate, chloride and several sili- cates, of which latter class, meerschaum is one (2MgO SiO^).

Salts of Magnesium are found in sea water and many mineral springs, also in animal and vegetable bodies.

The element itself is generally obtained by heat- ing the chloride with metallic sodium.

Magnesium. 165

MgCl2 + 2Na = mixQl + Mg

Mafj:iicsium Chloride.

It is a bluish white brittle metal, somewhat mal- leable and ductile; melts at a red heat; is not af- ected by dry air, but oxidizes in moist air. Heated to redness, it takes fire, and burns with an ex- tremely brilliant white light, very rich in the ac- tinic chemically active ways; for this reason it is used as a source of illumination, in photographing the interior of caves, etc.

Magnesium Oxide, MgO, is a white, infusible, in- soluble, bulky, antacid powder, known as magnesia.

Magnesium Sulphate, MgSo^ 7H2O, is found in nature, as Epsom salts, and may be prepared by dissolving the oxide, hydrate, or carbonate, in sul- phuric acid. It consists of colorless, odorless, soluble crystals, of a bitter taste; used in medicine as a purgative.

An interesting feature in connection with the water of crystallization in MgS04 TH^O, is worthy of notice. At a temperature of 120° (248F.) only six of the seven molecules of water are driven off; the remaining molecule persistently resisting ex- pulsion until the temperature reaches nearly 200° (892F). This last is known as water o^ constitution, and may be replaced by certain sulphates, as for instance K2SO4, yielding a doable sulphate.

166 Inorganic Chemistry,

SO.K

MgSO,, H^O 6H2O + K^SO, = Mg{ ^^^^ } 6S0,

I pi rj Potassio-Magnesium

^^^2^ Sulphate.

This compound serves as a type of double salts, and is isomorphous with those produced by the union of the alkali-sulphates, with the sulphates of zinc, copper, nickel, iron and cobolt

Potassio-Ferrous Sulphate,

Showing also that there is some chemical relation- ship between magnesium and the metals just named.

Cadmium (Cd), is comparatively rare, occurs chiefly as an impurity in zinc, and as a sulphide; the precipitated sulphide, CdS, is a yellow pigment of great beauty, highly prized by artists. Cad- mium is obtained by converting the sulphide into oxide, and reducing the latter, by heating with charcoal. It is a lustrous bluish-white, tinlike metal, of sp. qr. 8.6, at. wt. 112, vapor density one-half the atomic weight, hence its molecule is composed like that of mercury, of only one atom. It melts at 260° (500F.) • tarnishes gradually in the air, and is acted on slowly by acids, and by chlo- . rine, sulphur, and oxygen. Its salts resemble those of zinc; the metal itself is malleable and ductile,

Cadmium- GrlucinuM. 167

but of no importance, except as a constituent of some fusible, and amalgam alloys.

Beryllium or Glucinum, (G1), is a rare metal, occurring in certain silicic minerals, and as an ahi- minate. It is a white metal of sp. gr. 2.1 mallea- ble, and sets hydrogen free from acids. Its salts have a sweetish tasts, whence its former name, gluciniun.

168 Inorganic Chemistry.

CHAPTER XI.

LEAD, ETC.

Symbol, At. Wt. Sp. Gr. Valency, Pb. 206.5. 11.40. II-IV.

Lead was well known to the ancients, and is still an abundant and useful metal. It is found princi- pally as a sulphide in galena, but also occurs as a carbonate, sulphate, phosphate and arsenate.

Lead is a bluish-white metal, soft enough to be easily cut with a knife. The brilliant freshly cut surface quickly tarnishes in moist air. It is malle- able and ductile, but possessed of very feeble te- nacity ; melts at 320 (608F) ; is acted upon by nitric, sulphuric, hydrochloric, carbonic, and acetic acids, and by oxygen, sulphur, chlorine, bromine and iodine.

All the salts of lead are poisonous. Waters con- taining nitrates from decomposed animal matter, and clorides, are not safe when passed through lead pipes. Hard waters, how^ever, containing carbon- ates, and sulphates, are relatively safe, as the lead carbonate forms an insoluble protecting crust on the interior lining of the pipe, unless a considera- ble amount of free carbonic acid is present. As a

Leady etc. 169

precaution it is best to allow water that has been long standing in lead pipes, to flow until the fresh portion from the mains appears. Lead salts in water can be detected by adding a few drops of hy- drochloric acid and then a strong solution of sul- phuretted hydrogen. If lead is present, a dark brownish color will result.

Cylinders of metallic lead have been successfully employed for filling root canals of teeth, the lead sulphide and carbonate, formed therein, probably acting as antiseptics, but as these salts, especially the sulphide, injure the normal color of the tooth, the practice of using lead for such purposes, is not much in vogue. In dentistry lead is more espe- cially used for making counter-dies. In the arts it is used alone, and alloyed with other metals, for various purposes.

Its compounds are important. Lead oxides are used as coloring for porcelain teeth. The hydrated carbonate, 2PbC03, (H0)2,is the basis of the well- known paint, ivhite lead. The monoxide, PbO, is known as litharge, and this, if heated in a current of air, is converted into red lead, PbgO^.

Materia Medica. — All the salts of lead are used, as a rule, only as external applications. They are soothing and astringent. The acetate,

15 : : •'■'• ':'.' /-. '•':'• •'

170 Inorganic Chemistry.

Pb(C2 11302)27 sugar of lead, is sometimes given internally as an astringent, in diarrhoea and haemoptyses.

Lead poisoning (painters' colic), indicated by a blue appearance along the gum margins, muscular weakness (drop wrist), constipation, etc., is a fre- quent affection of workers in lead pigments.

Antidotes. — Soluble sulphates, as magnesium sulphate, which cause formation of insoluble, and therefore, innocuous lead sulphate, followed by pot- assium iodide and sulphur baths.

Dose of lead acetate (sugar of lead), 0.10 Gm. (grjss)

The metal ThalliUxM (Tl), discovered by Crookes in 1861, by aid of the spectroscope, is a very rare element, although widely diffused ; occurring in very small proportions in iron and copper pyrites and in native sulphur. It is obtained from the flue-dust of sulphuric acid works. Although it is a triad, it resembles lead in nearly all its proper- ties. Its atomic weight is 203. The salts of Tl color the flame a brilliant green.

TIN.

Symbol, At. Wt. Sp. Gr. Valency, Sn. 1.18. 7.29. II-IV.

Tin is one of the metals of earliest antiquity. The principal ore of tin is the mineral cassiterite

c c «■

Tin, 171

stannic oxide, SnO^, found from time immemorial in England (Cornwall). Tin is now produced also in Borneo, Malacca, Banca, and to some extent in the United States, South America, and Australia, the purest coming from the island of Banca.

The metal is obtained by heating the crushed ore, with coal or charcoal, Sn02 + C = CO^ + Sn. It is soft, white, crystalline, malleable, slightly duc- tile, and feebly tenacious. Melts at 235° (455F), has a peculiar odor, and " cries " when a bar of it is bent ; retains its luster in air at common tempera- tures, but if heated, oxidizes readily ; is acted upon by dilute acids, and by the alkalies.

Tin is used largely in the arts; common tin plate is sheet iron, coated with tin, by immersion. Tin enters into the formation of many important alloys, and is used by dentists in the form of foil, as a fill- ing material, alone, and in mechanical combination with gold. The high preserving qualities of tin in this connection, are doubtless due to the formation between the filling, and the walls of the cavity, of the insoluble stannic oxide, and when with gold, in addition to this, an electrolytic mutual induction continues between the two metals, like that w^hich exists in, and preserves, galvanized iron, (iron and zinc).

There are tiro sets pf.tin compounds. The two

172 Inorganic Chemistry.

chlorides, viz. : SnClg and SnCl4, plus water of crys- tallization, are used as mordants in calico print- ing. These two chlorides, obtained by dissolving tin in hydrochloric and nitrohydrochloric acids re- spectively, yield with auric chloride, the beautiful " purple of Cassius," which is used in coloring por- celain.

Stannous oxide, SnO, is basic, and with acids forms a number of salts.

Stannic oxide, SnO 2, is peculiar, when compared with those metallic oxides we have thus far con- sidered, in being neither decidedly basic, nor acid; it is weakly basic with strong acids, and weakly acid with strong alkalies. This oxide is known as futty powder.

There are two acids of tin, whose formulas will

serve to explain the meaning of the prefixes, ortho

and meta, which are sometimes attached to the

names af certain acids and salts. Or^Aostannic acid,

H4Sn04, has four hydroxyl groups in its molecule ;

all its oxygen has a linking function, as the graphic

formula will show :

0— H

H— O— Sn— 0— H )— H

— Sii — being a..tetrad,«;Beqjiiri5s four groups of

A.

< • < • <

Tin. 173

hydroxyl (0H)4, to satisfy its equivalency oi four. In all ortho-acids, there should be as many hydro- gen atoms as oxygen atoms; that is, the number of hydroxyl (OH) groups should be the same as the valency of the receiving radical, which, in the case of Sn, is four. Phosphorus is a pentad, P^ Ortho-phosphoric acid should therefore have jive hydroxyl groups P(0II)5.

yifefa-acids are derived from ortho-acids by ab- stracting a molecule, or molecules of water, from the latter. In meta-acids the atoms of oxygen serve a saturating as well as a linking purpose Thus, Meta-stannic acid, H2Sn03, is ortho-stannic acid, minus one molecule of water:

0-H 0

I II

H-O-Sn— 0-H H— 0-Sn

0-H 0-H

Ortho-Stannic Acid. Meta-Stannic Acid.

Where tino molecules of water can be removed from an ortho-acid, a r/me^a-acid results; Mree mole- cules of water removed, a trimeta-acid, etc.

0-H 0

I II

H-O^P -0-H H-0^^

H-0^ ^0-H 11-0--" ^^0-H

Ortho phosphoric Acid. Metn-phos. Acid.

o

H-^0 ^:r--^.0=i=HPOv, etc.

' , M)tn^i;»a-«pbc«.»i'.c\d. . •'• ••» >

"i^V:-... ..,

174 Inorganic Chemistry.

The salts of ortho and meta-acids are named with corresponding prefixes.

Stannic sulphide, SnS2, is a golden yellow pow- der, called " Mosaic gold," used for bronzing.

Materia Medica. The medicinal value of tin compounds is nil.

Titanium, Zirconium and Thorium, belong to the tin group of elements. They are extremely rare; are tetrads, like carbon, silicon, and tin, to whom they are closely related in the gradation of their physical properties, and in the similarity of their chemical compounds. The gradation being in the following order :

Carbon, Silicon, Titanium, Zirconium, Thorium,

Tin.

• •••• • ••• •*; I

\: '.: r- -.:>-

1 • • •

• • •

• • •

Aluminum, 176

CHAPTER XIl.

ALUMINUM, ETC.

Symbol, At. Wt. Sp. Gr. Valency, Al. 27. 2.6. IV.

Aluminum next to oxygen, and silicon, is the most abundant of the elements, the crust of the earth being made up mainly of those three. The minerals, corundum, emer}-, ruby and sapphire, are aluminum oxide, and the various kinds of clay, as well as feldspar, mica, slate, granite, basalt, etc., are essentially aluminum silicates. Hydraulic cement contains al-silicate.

The process of Deville, discovered in 1854, of heating together in a reverberatory furnace a defi- nite mixture of fluor spar, sodio-aluminum chlo- ride and metallic sodium, furnishes a clue to the mothod^ ad()})ted, for obtaining the metal. AL.dg + Nag = 6NaCl + 2A1

This process has been superseded of late years by various modifications, by which aluminum is produced almost pure, (98 per cent), and compara- tively inexpensive.

Aluminum is a brilliant bluish-white metal, sus- ceptible of receiv^ng^d'iiigh 'j>o(i'4J!i,;'i8 very malle-

> > » > I

> » » I ,

' "• '.'•.';.,;

176 Inorganic Chemistry.

able, ductile, and possessed of considerable tenacity. It is acted on by aqueous solutions of strong alka- lies and hydrochloric acid, but is unaffected by other cold acids, inorganic or organic; is not af- fected by sulphur, and therefore may be conjoined with rubber in vulcanizing the latter substance ; it does not oxidize in bulk, but if thin leaves be heated in oxygen, it burns readily. It melts at 700° (1292F).

On account of its lightness, permanent purity, and the tensile strength of the metal and its alloys, it is being largely introduced of late into the arts for many purposes. It can be cast alone or alloyed with silver or copper, into forms of singular beauty. 10 parts silver and 90 of aluminum ex- hibits a splendid white non-corrosive alloy; 90 parts of copper and 10 of aluminum, constitutes aluminum bronze, resembling gold in color, and ca- pable of receiving and retaining a high polish. In thin leaves it has been used, with some euccess, as a lining for rubber plates. An alloy of 100 parts of aluminum and 10 of tin, is employed in the making of philosophical instruments. The apex of the Washington monument is of alu- minum.

Aluminum plates, either cast or swaged for arti- ficial dentures, ka>ve \tak$ii*:£5n important rank in

••• • » •«••• .... •• • ••••

«• • ••• •••

• •«• « •**

• • • •

, • • • •: • • •,

Aluminum. 177

dental prosthesis. They possess special properties often requisite for certain mouths.

Alum, from which the metal takes its name, is the most important compound of aluminum. Com- mon potash alum is a double sulphate of aluminum and potassium, Al2(S04)3,K2S04,24H20, or AI2 K2 (80^)4,241120. Ammonium alum is Al2(]SrH4)2 (804)4,241120. There are alums also of Xa,Cs, Rb, Ag, and Tl, wherein these elements respect- ively occupy the place of K or NH4 ; and there are alums in which the aluminum itself is replaced by Fe, Cr, and Mn, respectively. Each molecule of alum contains 24 molecules of water of crystal- lization.

Ordinary alum is manufactured on a large scale by action of sulphuric acid on some of the various aluminum silicates, whereby aluminum sulphate, AI2 (804)3, is formed. This is then added in solu- tion, to a solution of potassium sulphate K2SO4, Or ammonium sulphate NH48O4, as the case may be. The alum crystallizes on evaporation of the liquid mixture.

Alum has an astringent sweetish taste, and acid reaction; is soluble in water, the hot solution be- ing a good pickle for removing borax glass from gold, etc., after soldering. By heating for a con- siderable time, at a temperature of 80° (176F), all

178 Inorganic Chemistry.

the water of crystallization is driven out, the alum then becoming caustic alum.

Aluminum Oxide, AI2O3, alumina, is found crys- tallized in nature, in many varieties, as corundum, emery, ruby, etc.; colored by impurities, as sapphire, which is simply blue corundum; "oriental amy- thist" is purple, "oriental topas" is yellow, and "oriental emerald" is green. These gems can be produced artificially.

The oxide is prepared by igniting the hydrate (the latter obtained by mij{:ing a solution of alum with excess of ammonia), presents a white, tasteless, co- herent mass, very slightly afiected by acids, and fusible only in the oxyhydrogen flame.

The hydrate Al2(H0)g ortho-aluminum hydrox- ide, prepared as above, forms with strong acids, characteristic salts, like al-sulphate, already men- tioned. With basic radicals, it acts as an acid, forming aluminates, as ortho-sodium aluminate, ^agAlgOg. There are also the mono-meta hydrox- ide, Al2 0(HO)4, and the dimeta-hydroxide, AI2O2 (HO) 2, forming with bases, mono-meta and dimeta- aluminates, respectively, as dimeta-potassium alu- minate, K2AI2O4, etc. Aluminum" hydrates are largely used in calico printing, as mordants, inas- much as they are able to unite with organic dye- stuffs, to form "lakes," which are insoluble; the

Aluminum. 179

(litfereut colors being thus "fixed" in the fiber of the cloth.

There are normal, and basic {i. e., containing hy- drogen), aluminum phosphates found in nature, of which, the turquoise, Al4(r04)2,(HO)g,2H20, is an example. The topaz is fiuo-aluminum silicate, the beautiful blue " lapis lazuli" is sodio-aluminum sili- cate, containing sulphur. Its powder was formerly used by artists, under the name of " ultra marine." This substance is now produced very cheaply ; vio- let, red, and green ultra-marines are also prepared artificially.

Clay is the result of the disintegration of the ua- stratified, primitive rocks, as granite, porphyry, etc., and further of felspar, etc., these rocks consisting, in great part, of this mineral.

The art of pottery making has been known from the earliest times. Porcelain manufacture, in Eu- rope, is of comparatively recent date, being derived, probably, from China, whence the name " China- ware." Porcelain differs from pottery, in being translucent, and differs from glass in being non- transparent, and much more infusible.

Porcelain clay, or kaolin, is a hydrous aluminum silicate — , II2 Al2Si20g,H20, derived by atmos- pheric influence on felspar, which is K2Al2SigOig. When prepared for the furnace, and baked, it loses

180 Inorganic Chemistry.

its water, yielding a porous " biscuit." This is dipped in a thin mixture of pure felspar and water, and "fired" again; the felspar being fusible, "glazes" the surface into a smooth finished pro- duct. The ornamental part, of gilding, and paint- ing in enamel, is next accomplished, and the piece (pieces) heated again to flux the colors. The colors consist ofpigments of metallic oxides ; cobalt oxide for blue, chromic oxide for green, etc.

Crucibles and fire-brick contain extra proportions of silica.

Porcelain teeth are manufactured by processes sim- ilar to those employed in making porcelain ware. The 6o6/i/ consists chiefly of felspar, kaolin and silica (Si02) ; the enamel, mainly of felspar. The differ- ent shades of enamel are produced by fine division of various metals, or of metallic oxides (purple of cassius, for instance). A representation of a gold filling may be obtained by applying a mixture of precipitated gold, or auric chloride and chamomile oil to the limited part desired on the surface of the tooth, and heating. (See Gold.)

Materia Medica. Alum, alumen, possesses styp- tic and astringent properties, condensing the tis- sues by coagulating their albumen ; dried alum, alumen exsiccatum, is mildly caustic. In large doses,

Aluminum. 181

taken internally, alum acts also as an emetic and purgative.

Alum is employed locally to arrest alveolar hemorrhage, and in solutions of varying strength, in treatment of spongy gums, of congested mucous membrane of mouth and throat, and for relieving the inflammation and soreness, induced by wearing artificial dentures, and as an injection in many flowing diseases; and as a collyrium. Powdered alum, added to Laharragues solution, makes an ef- fective bleacher for discolored teeth.

Aluminum chloride., sulphate, and acetate, are dis- ir>fectants and antiseptics. Very weak solutions of either of these, will effectually neutralize offensive breath, arising from catarrhal affections.

The chloride is sometimes used for bleaching teeth.

Dose. Alum 0.65 — 1.00 Gm. (gr.x — xv).

Alum (dried), 0.25 — 0.65 Gm (gr.iv — x).

R. Aluminis, 4.00 Gm. (^i).

Tinctura myrrhse, 15.00 fGm. (f^ss). Aq. Dest. q. s. ad. 60.00 fGm. (f^ij)

M. S. Apply to spongy gums.

Gallium, Indium, etc.,

Ga. In.

These metals are chemically related to aluminum. They are extremely rare, only traces of tliem being

182 Inorganic Chemistry.

found in zinc blende. The atomic weight of Al is 27, of Ga 70, and of In 114, a regular gradation ; the specific gravity of Al is 2.6, of Ga 5.9, and of In 7.4, a regular gradation. Both gallium and in- dium were discovered by spectrum analysis. Their sulphates form ammonia alums.

Gallium, and the rare metal scandium., are of es- pecial theoretical interest, on account of their ex- istence and properties, having been predicted in advance of their discovery.

Iron. 183

CHAPTER XIII.

IRON.

Symbol, At. Wt. Sp. Gr. Valency, Fe. 56, 7.8. II, IV, VI.

Ever since the ante-historic times of Tubal Cain, who was a worker in iron, this metal has held its own as one of the most important substances in nature.

It is abundantly distributed, although but a very small quantity of native iron has been found ; a large proportion of meteors consist of metallic iron. Iron is a constituent of innumerable min- erals, is present in all kinds of rocks, and soils, in the waters of nearly all mineral springs, and in the bodies of plants and animals.

The ores from which iron is obtained, however, are practically very limited in number. These are, chiefly, magnetic oxide (magnetite), Fe304 ; ferric hydrate (limonite), 2Fe203 3H20; ferric oxide (he- matite), Fe^Og ; and ferrous corbonate (siderite), FeCOg. Those ores that are not native oxides, are converted into artificial oxides by roasting, so that practically, the chemical process of producing

184 Inorganic Chemist?^.

iron on a large scale consists essentially in reduc- ing the oxide with carbon. Alternate layers of the ore, fuel, and limestone are placed in the " high furnace," and hot air forced upward through the mass, producing such a high temperature that the oxygen leaves the ore, and takes up with carbon, leaving iron in the metallic state:

Fe203 + 3C = SCO + 2Fe.

The limestone serves as a flux in removing silica and other impurities, which fuse into a "slag," and remain on top of the molten iron. The process is continuous, until the furnace wears out; the mate- rials being added at the top and the melted slag and iron drawn off at the bottom at regular inter- vals. The metal is drawn off into molds, and is known as cast or pig iron, and contains a good deal of carbon^; this is burned off in a reverberating furnace, together with sulphur, silicon, phosphorus, and other impurities in the form of oxides. This operation is known as '' puddling," the result being wrought iron.

The different varieties of commercial iron con- tain more or less carbon. Cast iron contains the most carbon, 2 to 6 per cent. Steel considerably less, 0.5 to 2 per cent, and wrought or malleable iron, less than 0.5 per cent.

Wrought iron is fibrous in structure, and tough;

Iron. 185

at a high temperature it becomes pasty, in which condition it is susceptible of welding.

The melting point of iron is very high, probably above 2000° (3632F). It is malleable when hot, and ductile, and possessed of superior tenacity ; and when pure is white.

Iron is acted upon by hydrochloric, and sulphuric and dilute nitric acids, and by the haloids; and when heated, by phosphorus, sulphur, and oxygen.

It would be doing more than our requisite duty to attempt to name the uses to which iron is ap- plied in the arts; and w^ould be a work of superero- gation also, to consider its numerous compounds in their chemical relation to commerce, the arts, and medicine.

Ferrous Salts, which may be regarded as derived from ferrous oxide, FeO, are mostly pale green in color.

Ferrous Sulphate, FeSo4,7Il2 0, commonly called green vitriol, or copperas.

Ferrous Chloride, FeClg, and /errors iodide, Yel^, are pale green, and soluble. Ferrous sulphide, FeS, made by fusing iron and sulphur together, dissolves in dilute acids, with evolution of II2S.

Ferrous Carbonate, FeCOg, a. white precipitate, produced when solution of a ferrous salt, as FeSO^, is added to a solution of an alkaline carbonate, as 16

186 Inorganic Chemistry.

ITagCOg, on exposure to the air, this ferrous car- bonate decomposes into free CO 2, and Fe2 03 ; the latter substance is known as "jeweler's rouge" (polishing powder), and as the pigment, "Yenitian red." All ferrous compounds are prone thus, to take up oxygen from the air, and become changed into ferric compounds, which are chiefly, either red or yellow.

Ferric oxide, FcgOg, sesqui oxide of iron, may be considered the basis of the ferric salts. The oxide itself has been sufficiently described.

Ferric Chloride, Fe2Cl6, perchloride of iron, can be prepared by dissolving ferric oxide in hydro- chloric acid, or by direct action of CI on iron, or by heating the hydrate in the presence of CI. It consists of orange red, deliquescent crystals, of strong styptic taste, and acid reaction, and very soluble in water and alcohol.

Ferric hydrate, Fe2(H0)gf hydrated peroxide of iron, is obtained as a reddish precipitate, when either ferric chloride or ferric sulphate, in solution, is added to solution of ammonia (or caustic alkalies). It is the favorite antidote to arsenic ; should be made fresh, washed in water, and given ad libitum.. Iron rust, is ferric hydrate.

Ferric sulphate, FeS2, iron pyrites, sometimes iirt

Iron. 187

called '' fools gold/' is used in the manufacture of copperas and of sulphuric acid.

Ferric sulphate, re2 (804)3, persulphate of iron, prepared by boiling a solution of ferrous sulphate and sulphuric acid, and adding nitric acid. On evaporation it appears as a buff-colored mass, slowly soluble in water. Practically, however, the above solution is not evaporated; it is a clear brownish-red liquid, of slight odor, very styptic, and of somewhat sour acrid taste.

MonseVs solution, subsulphate of iron solution, an oxy-sulphate, probably 2Fe2 03,(804) 3. The solu- tion is prepared as above, except that only one- half the amount of sulphuric acid is employed. It is of a deep ruby red color, no odor, and of a very astringent but not acrid taste. MonseVs powder of the subsulphate, possesses the same properties as the solution.

Magnetic iron oxide, FeO, Fe203, ferroso-ferric oxide, is incidentally produced in the shops in the form of " iron-scales."

Dyalized iron is essentially an aqueous solution of the hydrate obtained from a mixture of ferric chloride and ammonia ; the ammonium chloride formed, passes through the dyalizer, leaving the iron in a colloid state. It is inodorous ; of a non-styptic taste, and considered by some a good chalybeate.

188 Inorganic Chemistry.

Iron by hydrogen, reduced iron, metallic iron in fine powder, gray-black in color, produced by pass- ing a stream of hydrogen over heated ferric oxide.

Materia Medica. — Salts of iron, combined with vegetable astringents, form ink. They are, there- fore, incompatible with tannin.

The per-(ferric) salts of iron have a decided local influence in arresting passive hemorrhage, their astringency causing contraction of the small ves- sels; and by coagulating their albumen, a corru- gating and hardening of the tissues.

Whenever it becomes advisable to use a hse- mostatic after the extraction of teeth, either the perchloride in semi- crystallized form, or in solution ; or the liquor ferri chloride (ferric chloride crystals, 37.8 per cent, in water), or Monsels powder or solu- tion may be selected for the purpose, and applied with a prospect of more than average success. We would not recommend these salts of iron, how- ever, in gargles or washes for mouth or throat, \u- asmuch as they undoubtedly corrode the teeth.

The principal indication for the internal exhibi- tion of iron, is as a tonic in ancemia. Iron being an essential constituent of the red corpuscles of the blood, it not only augments the quantity of haemo- globin, but increases the number of the red corpus- cles as well ; furnishing thus, by an extra supply

Iron. 180

of healthy blood, fresh stimulus to the muscular fibers of the heart. It tones up the mucous mem- brane of the stomach, inducing improved appetite and digestive power. It increases the temperature by reason of its function of carrying oxygen to the tissues.

190 Inorganic Chemistry,

CHAPTER XIV.

IKON — Continued.

The actual state in which iron exists in the red corpuscles, and the exact relation it bears to the operations in tissue waste, are not definitely known. We may assume, however, with some degree of safety, that when it takes up, in the lungs, the oxygen, received from the air, by inhalation, the chemical state, in which it passes through the arte- rial circulation to the capillaries, is as ferric oxide (FegOg). In the process of tissue waste, some, per- haps many, of the molecules of this compound are reduced to ferrous oxide (FeO), thereby setting free nascent oxygen, which at once plays its part by uniting with the carbon (and other elements also), of the tissues, which union produces CO2. Now, CO2 does not long remain free ; it finds the reduced iron oxide, and they unite, producing fer- rous carbonate, according to the simple equation, FeO + Co,=:FeC03.

The ferrous carbonate, thus formed, is carried through the venous circulation to the capillaries of the lungs, where it suffers decomposition by the in-

Iron, 191

fluence of the inspired oxygen of the air; the CO2 es(;aping in the respiratory exhalation, while the FeO takes up with the oxygen present, 2FeO-|- 0=Fe,03.

Sach, in brief, are probably the principal reac- tions, involving iron, that occur throughout the circulation. They afford us a fair idea of at least two important functions performed by iron, namely, the carrying of atmospheric oxj'gen from the lungs to the capillaries, via the arterial circulation ; and of the carbon dioxide, by way of the veins, from the capillaries to the lungs.

A question of some import occurs in this con- nection. Does the CO2, formed continuously in every portion of the living animal body, have any influence at the time of its development, in pre- venting the oxygen of reserve from a too active par- ticipation in the oxidation of the tissues? And does its presoncie, while yet free, previous to its union with FeO, tend to keep the normal process of oxidation of tissues from being painfully mani- ifest to our consciousness, by governing, with just the exact amount of pressure required, the con- ductivity of the peripheral extremities of the sen- sory nerves, or by primary influence, through the same direct means, on the receptive centers of the brain itself?

192 fnorganic Chemistry.

If CO., is possessed of the attributes indicated, then any increase for the time being, in the amount produced, or any means that will prevent, even temporarily, the regularity of its removal from the body, will induce a corresponding reduction in our perception of pain. Rapid breathing, " holding the breath," experimentally, or as we do instinctively, while awaiting a shock, violent exercise, and men- tal excitement, are all productive of either an in- crease in the quantity of CO 2, or of its temporary retention throughout the tissues ; and w^e all recog- nize, as a fact, that the above means are effective for the time being, in lessening our susceptibility to pain. Cause and effect seem, in these instances, to agree.

Physical causes — molecular physics — although they may not be appreciable to our senses, are in- volved in all forms, plus or minus^ of nervous or mental phenomena, including the so-called hyp- notic influence ; but in explaining the physiological action of certain drugs, we are frequently com- pelled to dismiss the subject by saying, " they have a direct effect on the nervous system," or some par- ticular set of nerves. .

In all experiments with nitrous oxide, it has been found to be active only as a carrier of oxy- gen. Combustibles burn in it with more energ^^

Iron. 193

than in the air, the heat setting the oxygen free, oxide compounds only resulting. It has also been ascertained, that when inhaled, ^2^ dissolves in the arterial blood, unchanged. In this way it supersedes the legitimate carrier of oxygen, Fe^Og, and the latter compound, not being allowed to de- compose, in the capillaries, into ferrous oxide, FeO, the CO2 that is formed, in much greater abun- dance than usual, by the oxygen of the N2O, can not escape in the usual way, as ferrous carbonate; much ot it, comparatively, remains free, for the time being, causing at first, the pleasurable excite- ment, exaltation of the faculties, hallucination, anoesthesia, and finally a state of carbon dioxide as- phyxiation, which are observed to take place when ^2^ ^^ inhaled.

Nitrous oxide is, therefore, not an asphyxiating agent per se. It so acts indirectly, only when pushed to the extent of developing and accumu- lating CO2, in quantity necessary for the purpose, the danger line moving to and fro, according to the individual. The relative immunity from danger, with N2O as an anaesthetic, may be accounted for by the exaggerated oxidation of carbon (a natural process), which immediately ensues ; and the rapid escape of the active compound, CO2, as soon as

air is admitted, which at once restores to iron the 17

194 Inorganic Chemistry,

opportunity of performing its accustomed duties in the circulation.

MANGANESE.

Symbol, At. Wt. Sp. Gr. Valency, Mn. 54. 8. II,IV,VL

Manganese is closely related to iron. It occurs somewhat abundantly, mainly as an oxide, Mn02, which ore, when ground, is known as the black oxide of manganese.

The metal is chiefly obtained from the black ox- ide, by reduction with carbon. It is gray-white, lusterless, resembling cast iron, brittle and very hard, very difficult to melt, and decomposes water^ setting hydrogen free. With copper it forms a beautiful alloy.

Four well defined oxides, MnO, Mn02, Mn203, and Mn3 04, are known. The first is strongly ba- sic, the third is weakly basic, forming, with acids, typical salts, and with basic oxides it acts as acid, forming salts called manganites. The second and fourth oxides are neutral.

Hydrogen permanganate, H2Mn208, permanganic acid, produced by distilling potassium perman- ganate with sulphuric acid, is a most powerful oxidizer, setting fire to alcohol, paper, etc. Its most characteristic salt is potassium permanganate,

Cobalt, Nickel. 195

K2Mn208, prepared by mixing manganese dioxide, potassium chlorate and potassium hydrate in a Httle water, evaporating and heating to red heat. It presents, as dark violet crystals, soluble in water, the dilute solution, exhibiting a superb purple color. It readily parts with its oxygen in the presence of organic matter, as alluded to under potassium.

COBALT, NICKEL.

Co. Ni.

Both cobalt and nickel are closely related to iron, but are comparatively rare. The atomic weight of cobalt is 59, of nickel, 58, and of iron, 56. The specific gravities of these three metals are also about the same, and their valency is the same.

Cobalt occurs in nature as a sulphide, C03S4 ; as an arsenide, CogAsg ; as an arsenate, C03 (As04)28H20; as speiss-cobalt, Col^iFeAsg ; and as cobalt-glance, CoFe (AsS)2. Many of the com- pounds of cobalt are used as pigments and for col- oring porcelain and glass. A solution of cobalt- ous chloride, C0CI2, in water, furnishes sympa- thetic ink of a blue color, when heated, but which becomes invisible on cooling, by absorption of moisture.

XiCKEL' is always a constituent of meteoric iron.

106 Inorganic Chemistry.

Its chief sources are, as the arsenide, kupfernickel, a yellow ore, whence its name ; and as sulphides and silicates of nickel. The metal is used some- what extensively for coating other metals by elec- trolysis, the electrolyte employed being the double sulphate of nickel and ammonium (^"£[4) 2 ^1(804)2, 6H2O, dissolved in water. The lower salts of nickel are generally green. An alloy of nickel and copper is the familiar instance of the " nickel." German silver is nickel, copper, and zinc.

Like iron, both cobalt and nickel are magnetic. They are also malleable and ductile, and occupy the first rank in tenacity, like iron, and are affected by acids similarly to iron. The color of cobalt is reddish-white.

Arsenic. 197

CHAPTER XY.

ARSENIC.

Symbol, At. Wt. Sp. G-r. Valency, As. 75. 5.7. III-V.

Elementary arsenic is inert, but its soluble com- pounds are extremely poisonous. It is found free, and in a great many minerals, in company with sulphur, iron, cobalt, nickel, etc., as sulphides, ar- senides, arsenites, and arsenates. It is chiefly ob- tained, however, from arseno-pyrites, a sulphide of iron and arsenic, by sublimation, the arsenic being volatile. Its vapor has an odor of garlic, by which its presence may be indicated, when heated by the blow pipe. Like phosphorus, its molecule con-

sists of four atoms, T^^y inasmuch as its va-

A.S .A.8,

por density is 150. Arsenic is a dark-gray, brittle solid, metallic in appearance; classed by some as a non-metal, by others as a metal ; it is about mid- way, in chemical properties, between these two classes of elements. About the only purpose for which metallic arsenic is used, is for hardening lead ^' shot." A very impure variety is sold as a

198 Inorganic Chemistry.

fly-poison, under the erroneous name of " cobalt." "Marsh's test" for arsenic, consists in the devel- opment of " nascent" hydrogen, in the presence of the suspected mixture. Pure zinc and dilute hy- drochloric acid will accomplish this, and if arsenic is present, it will escape as ursine, AsHg, an exceed- ingly poisonous gas, one bubble of which proved fatal to its discoverer, Gehlen. This gas, as it es- capes from a jet, arranged with proper precaution, when kindled, will deposit a mirror-like stain of metallic, As on a cold, clean surface of porcelain, held in the flame. Antimony compounds will give similar results, forming SbHg, but the deposited arsenic is soluble in sodium hypochlorite solution, whereas the antimony is not. It is said that 5-0V0 of a grain of arsenic can be detected in this way. Two oxides of arsenic, and their corresponding acids are known.

AS2O3 + 3H2O = 2H3ASO3

Arsenous Water. Arsenous

Oxide. Acid.

AS2O5 + 3H2O = 2H3ASO4 Arsenic Arsenic

Oxide. Acid.

Arsenic compounds are not so poisonous as the arsenous, and not so important.

Arsenous oxide, AS2O, exhibits such momentous qualities, that it has appropriated the very name of arsenic^ and is generally known as such. It is

Arsenic, . 199

formed by roasting arsenical ores in air, collecting the vapors and resubliming; it exists in two varie- ties, one crystalline, and the other in lumps, re- sembling porcelain; the latter is the usual com- mercial variety, the powder being white and heavy, of a gritty feel, tasteless, and odorless, and un- changed in air. It is slowly soluble in water, giv- ing rise to arsenous acid, whose salts are known as arsenites. The arsenites of the alkali metals are soluble in water; the arsenites of iron and mag- nesium not so, hence the employment of iron and magnesium hydrates, as antidotes. Sodium ar- senite NagAs, as a mordant is used in calico print- ing; and the brilliant pigment, Paris-green, a double salt of copper arsenite and copper acetate, Cu3Aa2 Cu (0211302)2 is extensively used for col- oring wall-papers. Whenever such paper gives a green color to flame, or changes from green to blue, by a drop of aqua ammonia, the presence of ar- senic may be suspected.

Dissolved^ in acids, arsenous oxide forms salts, typical of the acid; as, for instance, from hydro- chloric acid solution, arsenous chloride, AsOlg, is obtained.

The 2 sulphides of arsenic, AS2S2, As^Sg, are known as the minerals, red realgar, and golden-yel- low orpimenl, respectively.

200 Inorganic Chemistry.

Materea Medica. — The official name of arsenous oxide, AS2O3, is Acidum Arsenosum, but it is com- monly spoken and written of as arsenic; also, as arsenous anhydride, arsenious acid, white oxide of arsenic, white arsenic, arseniosum oxidum, and ratsbane; in its medicinal consideration, we shall follow the custom, and call it arsenic.

When applied locally, arsenic acts as a severe caustic irritant, inducing redness and excessive in- flammation of the part, followed by suppuration and sloughing; for this reason, it is used some- times, as a cancer cure. In the operation of devi- talizing exposed dental pulps, it is the Samson upon which nearly all dentists confidently rely. The amount of arsenic necessary to destroy the life of the pulp need never exceed the ordinary internal dose. It is usually mixed with some prep- aration of morphine, or cocaine, of which mixture a paste with either creosote, carbolic acid, or oil of cloves, etc., is made and applied to the pulp, and sealed with gutta-percha, or cotton dipped in either sandorac varnish, or in a ssturated solution of aris- tol in chloroform.

A suggestive method that might decrease the period of pain, would be to apply a trace of pow- dered cocaine hydrochloride, say for five minutes, before inserting a paste, made of arsenic and solid

Arsenic. 201

caustic potash. Sometimes tannin alone, or in glycerine, is employed as an adjuvans to arsenic, on account of astringent properties. In all cases care must be observed, lest a part of the arsenic escape to the surrounding parts, inasmuch as the ar^senic bum is painful and slow to cure, and the al- veolar process itself might be, to a limited extent, completely destroyed. Certain individuals are peculiarly susceptible to the injurious effects of arsenic, and these do not suffer in having pulps devitalized, as do those who have strong resisting power against the action of the drug.

Taken internally in small doses, arsenic acts as a tonic, and antiperiodic, increasing appetite and digestion, producing a rotund form, and fair skin ; increasing the secretions of the primce vice, exsdtmg the mental faculties and stimulating the heart's action, and respiratory power. It is recommended in treatment of ague, neuralgia, asthma, dyspepsia, chronic skin affections, etc. When its use is con- tinued for some time, it usually causes oedema of the eyelids, ptyalism, disordered systemic condition, and eruptions of the skin. The arsenic eaters of Styria observe the precaution of not taking water into the stomach at the same time they partake of the drug, so that its slow absorption, and probably, rapid elimination follow. Toxic doses produce gas-

202 Inorganic Chemistry.

tro-enteritis, vomiting, diarrhoea, etc. In chronic poisoning, there is in addition, a fatty degeneration of the muscles and heart, and parenchymatous de- generation of the liver and kidneys.

Arsenic is usually given in the form of Fowler's Solution, Liquor potassii arsenitis, prepared by boil- ing together arsenous oxide and potassium bicar- bonate in water, to which the compound tincture of lavender is added. This preparation may be taken in water, always after meals, full doses at first, gradually diminishing as the treatment pro- ceeds.

Antidote. — Emetics (zinc sulphate), followed by freshly prepared hydrated iron (see Iron), and cas- tor oil.

Dose. — Liquor Potassii Arsenitis, 0.10-0.30 fGm.(TTL ij-v). Acidum Arsenosura, 0.001-0.006 Gm. (gr. -^\, j\).

R. Acidi Arseniosi, 8.00 Gm (^ij).

CocaiDi Hydrochloris, 2.00 Gm. (^ss).

M. S. For office use.

To prepare for devitalizing pulp, make a paste with caustic potash and carbolic acid. (Robinson's Remedy.)

Antimony.

Symbol, At. Wt. Sp. Gr. Valency,

Sb. 120 6.7 III— Y.

Antimony is not an abundant metal, although

Arsenic. 203

I'omparatively inexpensive. It exists in nature free, and as an oxide, a sulphide, and with silver and sul- phur. The metal may be obtained by heating its sulphide with iron, Sb2S3+Fe3=3FeS + 2Sb ; or hy roasting its sulphide, it is converted into an oxide, which is reduced by carbon.

Antimony is a blue-white solid, hard and very brittle ; does not tarnish in the air, but takes tire at a red heat ; is soluble in nitric acid, and forms synthetic binary compounds, with chlorine, oxy- gen, bromine and iodine. Zinc precipitates anti- mony from its solutions, as a black powder, which is used for giving plaster casts the appearance of steel. The metal melts at 450 (840F). A curious allotropic variety is obtained by electrolysis, w^hich is explosive when hammered or heated. The chief use of the metal is in giving hardness to alloys- Typemetal is an alloy of antimony, lead, and tin ; Britannia metal, of antimony and tin : and Babbit's anti-friction metal, useful for dies, is composed of antimony, lead, tin, and copper.

Antimony forms three oxides Sb203, Sb2 04, Sb2 05. The trioxide and pentoxide, like those of nitrogen are acid oxides, but their acids HSb02, IlSb03, unlike those of nitrogen, are very weak. There is also an ortho-antimonic acid, H^SbOg, and an ortho-antimonous acid, IlgSbOg.

204 Inorganic Chemistry.

Antimony and potassium tartrate, is a salt known as " tartar-emetic."

Antimonous chloride, SbClg, is the " butter of antimony," which is changed by water, into an oxychloride, SbClg -f H2O = 2HC1 + SbOCl.

Antimony oxysulphide, Sb2 02S2, imparts a yel- low tint to glass and porcelain. The nature of HgSb was sufficently indicated in the preceding chapter.

i

Bismuth. 205

CHAPTER XVL

BISMUTH.

Symbol, At. Wt. Sp. Gr. Valency, Bi. 208. 9.80. III-V.

Bismuth, like antimony, belongs to the same class with arsenic. It is principally found native, and is obtained by simply melting out the metal from adherent rocky matter and collecting in suit- able molds. It is comparatively rare, and besides its native condition, is found in only a few min- erals, as an oxide, a sulphide, a sulpho-telluride, and a carbonate.

It is a brilliant reddish- white, hard brittle metal; crystallizes in rhombohedroiis, which, on account of slight tarnishing in the air, present an iridescent appearance. It is acted on readily by nitric and nitro-hydrochloric acids, and by chlorine, but not by hydrochloric or cold sulphuric acids. It melts at 264° (507°F), and in solidifying, expands 3^ of its bulk, making a sharply defined cast when poured into a mold.

Bifemnth is important chiefly as a constituent of fusible alloys, one of which was described in a pre-

206 Inorganic Chemistry.

vious chapter. Another is composed of 3 parts of cadmium, 4 of tin, 8 of ead, and 15 of bismuth, which melts as low as 60° (140°F); and another, which melts at 82° (180°F), is composed of 1 of cadmium, 6 of lead, and 7 of bismuth. Other al- loys, of the above kind, serve as safety plugs for steam boilers, vulcanizers, etc.

In most of its compounds bismuth acts as atriva- lent base, such as the chloride, BiClg ; the oxide, Bi.^Og ; the sulphate, 312(804)3, and the nitrate, Bi(!N'03)3. When water is added in excess to a solution of a bismuth salt, the bismuth, salt decom- poses, a basic salt being precipitated.

The formation of bismuth sub-nitrate, HgBiOg NO 3, by dissolving bismuth in nitric acid, depends on this principle, although the process itself is rather complicated.

When water is added to bismuth chloride, BiCl3, a white precipitate of bismuth oxycloride results. BiClg + H2O = 2HC1 -f BiOCl. This latter substance is a white soft bulky powder, re- sembling the sub-nitrate, and is used as a "face powder." The following equation, BiClg + 3K0H = 3KCI + Bi(OH) 3, shows the formation of bismuth hydrate, a precipitate which, on drying, loses water, and becomes an amorphous white flocculent powder, less unwholesome to the skin

Bismuth, Vanadium and Tantalum. 207

than tlie oxychloride. This hydrated oxide, BiO(HO), is basic to strong acids, as sulpliuric, etc., and acid to strong bases , as sodium, etc.; for example, NaBiO^, sodium bismuthate.

Materia Medica. — Bismuthi sub-nitras is em- ployed locally, in powder, alone, or with charcoal, in eancrum oris, and other forms of ulceration of the mouth, in intertrigo, and as a snutf in inflam- mation of Schneiderian membrane, etc. It possesses astringent, sedative, and antiseptic properties, in virtue of which, it probably acts internally in re- lieving gastric pains, vomiting, and diarrhoea.

Dose.— 0.50— 1.00 Gm. (gr. viij— xv.)

Vanadium.

Symbol, At. Wt. Sp. Gr. Valency,

V. 51. 3.6. V.

Vanadium is an extremely rare substance ; it oc- curs in small quantity in some iron, lead, and cop- per ores, and is a non- volatile gray- white powder. It forms 5 oxides corresponding to those of nitro- gen, VjO, V,O„V,0„ V,0„ and Y,0,. Vana- dium compounds have very little practical import- ance. Tantalum and Niobium.

Ta. At. Wt. Nb. Valency,

182. 94. V.

These so-called metals are very rare. Both are

208 Inorganic Chemistry.

are black powders. They form acid oxides. W\o- bium is also known by the better name, Columhium.

Molybdenum, Tungsten.

Symbol, At. Wt. Sp. Gr. Valency, Mo. 96 8.6 VI.

Molybdenum is another rare element, occurring in small quantity, as a sulphide, M0S2, and as lead molybdenate. It is a white, brittle metal, almost ab- solutely infusible. When heated in air, it oxidizes to molyhdic oxide, M0O3, analogous to sulphuric oxide, SO3; molyhdic aci<i, H.^MoO^, is analogous to sulphhuric acid, H2SO4. Some of the molybde- num compounds are indispensable reagents.

Tungsten.

Symbol, At. Wt. Sp. Gr. Valency,

W (Wolfram), 184. 19.26. VI.

Tungsten is not abundant, but more so than molybdenum. It is found as ferrous tungstate, FeW04, in the mineral ivolfram, and as calcium tungstate, and lead tungstate. It is a white metal, hard and brittle, and very heavy, hence its name, signifying heavy stone; it is difficult to fuse, and when heated to redness takes fire, and produces tungstic oxide, WO3. A small addition of tungs- ten to steel, is said to confer on the latter, extraor- dinarv hardness and fineness.

Uranium. 209

The oxide, WO3, is an acid oxide, the corre- sponding acid having the formula, H2WO4. The tungstate of the alkali metals (more especially of sodium, NagWO^), are sometimes used as mor- dants, and for rendering light cloth fabrics unin- flammable.

Uranium.

Symbol, At. Wt. Sp. Gr. Valency,

U. 2.39. 18.68. VI.

Uranium is another rare metal, existing in only a few minerals ; it is found mainly in the form of an oxide.

When fused, which is difficult to accomplish, it is a white malleable metal, permanent in air, but if pulverized, and heated to about 200° (392F), it takes fire, and burns with great splendor, produc- ing a green oxide. It also shows great energy in uniting with chlorine and sulphur.

Uranium forms several oxides, which are basic in the presence of strong acids, and acid in the presence of strong bases, like those of tungsten. It is quadrivalent in tlie uranous compounds, as UCI4, UO2, U(S04)2, etc., and sexvalent in the uranic compounds. In the uranic salts the bivalent radical uranyl, UO2, is supposed to be the electro- positive radical, as in uranic oxide (uranyl oxide), (U0,)0; also (U0,)C1„ (UO,),2X03), (UO,)SO,). 18

210 Inorganic Chemistry.

There is no uranic chloride (UClg), or bromide, etc., as with tungsten.

Alkaline bases form salts with uranic oxide, UO3, known as uranates ; thus. Sodium Uran- ate, Na2 0, 2UO3, and Ammonium Uranate, Am20,2U03, which are known as " uranium yel- low," are used in coloring porcelain and glass, con- ferring a green-yellow color.

Chromium.

Symbol, At. Wt. Sp. Gr. Valency, Cr. 52. 6.81. YL

Chromium occurs somewhat more abundantly than the other metals of the chromium group. It occurs as lead chromate, and also in small propor- tion in several minerals, but is obtained usually from ferrous chromite, FeCr2 04.

Chromium, obtained by reducing its oxide by carbon, exhibits as a very hard, steel-gray mass, practically infusible ; obtained by reducing the chloride by zinc, it occurs as a glistening gray- green powder, showing minute tetragonal octahe- drons. It is unaffected in air, but burns, when heated in oxygen. It has been found in meteoric iron. It is readily acted upon by dilute hydro- chloric acid, less so by dilute sulphuric acid, and not at all by concentrated nitric acid. The metal itself is of no practical use, but its compounds are

Chromium. 211

both numerous and important; they are nearly all brilliant in colors, whence the name of the element, taken from a Greek word, signifying color,

Chromous chloride, CrCl2, is one of the most powerful reducing agents known. It precipitates gold from solution of auric chloride.

Chromic Chlroide, Cr2Clg, occurs in crystal- line plates of a pale violet color. Its hydrate, Cr2Clg9H20, is a dark green.

Chromous oxide, CrO, is a strong base, forming salts of a pale blue, but unstable, as they rapidly absorb oxygen from the air.

Chromic oxide, sesquioxide, Crg-Og, is a bright green powder. It is used in giving a green color to porcelain and glass, and to modify the yellow of titanium oxide in porcelain teeth. The emerald owes its color to this compound. It is basic or acid, according to the presence of acid or basic radicals.

Chromium trioxide, CrOg, may be obtained in superb crimson needles, by adding strong sulphuric acid carefully to a saturated aqueous solution of potassium bichromate, allowing the mixture to cool, and drying on a porous tile. It is a powerful oxidizing substance. A drop of alcohol coming in contact with the dry crystal, will ignite by the heat of the oxidation.

212 Inorganic Chemistry.

Chromic trioxide is the typical acid oxide of chromic acid and the chromates.

CrO^ + H2O = H2Cr04

(Chromic Acid.)

With potassium, for example, it forms the normal salt, K2Cr04, and by addition to this, of one more molecule of CrOg, we have potassium pyrochro- mate or dichroraate.

K^OrOg + CrOg = K2Cr207.

This salt is better known as hi-chromate of potash. It occurs iu splendid orange-red crystals, and is employed in the arts for various purposes; in pre- paring the chromium paints, in dying, in calico printing, and in photography. Gelatin containing the salt, remains insoluble wherever acted on by light, but is soluble in other portions : the photo- graph taken on such a film of gelatin stands out in bold relief, and can be copied in electrotype. This salt is also used in certain galvanic battery solutions.

By adding two molecules of 2(Cr03) to K2Cr04, we have K2Cr30iQ.

Plumbum chromate, PbCr04, is "chrome yel- low," which, by boiling with caustic alkali is con- verted into PbCr04,PbO, "chrome red;" and " chrome orange " is a mixture of these, the orange ray being intermediate between yellow and red.

Chromium. 2lS

Materia Medica. — Chromic acid is one of the most energetic disinfectants, in virtue of oxidizing

power. It should not be mixed with organic sub- stances. As an escharotic it penetrates deeply, and wlienever used in the mouth, in treatment of phag- edsenic ulcers, etc., it should be in suitable dilu- tion, and very carefully applied.

214 Inorganic Chemistry.

CHAPTER XVII. GOLD, ETC.

Symbol, At. Wt. Sp. Gr. Valency,

Au. 96.5. 19-4. I-III.

Gold, aurum ; the alchemistic " Rex Metallo- rum," has held its supremacy among the metals from the earliest historic times. It occurs native, and though very widely diffused, is not found in " paying " quantities outside of a few limited sec- tions, as in Australia, and the gold fields of the United States.

The association of gold in nature, is generally with quartz, iron oxide, in the debris or alluvial deposits of such rocks, and in the sands of various rivers. The only exception to its otherwise uni- versal existence in the metallic state, is as a tellu- ride, which also contains silver and other tellurides. Alluvial gold is obtained by washing, which sepa- rates the metal from the earthy matter. When a veinstone is worked for gold, it is crushed to pow- der, and if it contains pyrites, it is roasted; it is then agitated with mercury, which takes up the gold by amalgamation. The mercury is separated

Gold, 215

from the gold by pressure and distillation, and is recovered for future use. If traces of base metals are present, the gold is refined by passing chlorine gas through the melted metal. By quartatioriy it is separated from silver; the operation consisting of adding silver to the bullion, until the latter is made up of three parts of silver and one of gold. The alloy is rolled into thin ribbon, and then the silver in it dissolved out by nitric acid.

Gold possesses considerable tenacity, and ranks first* in malleability and ductility; it is soft, and crystallizes in isometric forms; its color is brilliant orange-yellow, by reflected light; and when beaten into very thin leaves, shows a bright green, by transmitted light. It melts at about 1100° (2012F.)

Gold is always alloyed with other metals, to give it the required hardness for practical use in the arts, except in the case of preparations of gold for filling cavities in teeth, wherein absolute purity is desirable.

Pure gold is 24 carats fine. The mint alloy of the United States is 22 carats ; that is, 9 parts of gold and 1 part of copper. Jewelers' gold is of a less carat, ranging downward from 18 to 12 carats. Copper confers a ruddy tint to the alloy, and silver a paler color. Platinum, or palladium, like Ag., glvee to gold a lighter shade ; the alloy, with small

216 Inorganic Chemistry.

proportions of platinum, is hard and elastic; with palladium, hard and brittle. Traces of such metals as antimony, tin, arsenic, bismuth, lead, etc., im- pair the malleability and ductility of gold, and render it intractable.

Dentists' gold foil, presumed to approximate 24 carats, is obtained by successive annealings and hammering of the ingot, until thin enough to pass between the rollers of a flatting mill. The thin ribbons of gold thus prepared are cut into small squares, and these are piled in considerable num- ber between pieces of vellum and parchment, and beaten; again cut into squares, and beaten; and finally hammered between " gold beater's " skins, until the required foil number is obtained.

Gold is practically unalFected by the air, sulphur- retted hydrogen, the alkalies, or any single acid, except, slightly, by selenic acid. It yields readily, however, to nascent chlorine, a gentle heat favor- ing the rapidity of the combination.

The chlorine for the purpose, is usually produced by mixing 3 parts of hydrochloric acid with 1 part of nitric acid, the mixture being known as aqua regia, alluded to in a previous chapter.

To obtain free gold from its alloy with copper, and silver, or other metals, or either one alone, dis-

Gold. 217

solve the alloy in aqua regia, facilitated by a gentle heat. The reaction will be as follows:

12HC1 + 4IIXO3 = 8H^0 + 4N0C1 + 8C1. 6C1 -I- Au + Cu + Ag == AuClg + CuCl^ + AgCl.

The silver chloride falls down as a white curdy precipitate, and the chlorides of gold and copper remain in solution; it now remains to precipitate the gold, and leave the copper in solution. This is accomplished by various reagents, of which, two only need be mentioned, namely, solutions of fer- rous sulphate (copperas), and oxalic acid. The ferrous sulphate is changed into ferric compounds, and the oxalic acid into carbon dioxide, and hydro- chloric acid, thus : 6FeS04 + 2AUCI3 = 2Fe2(S04), + Fe2Cl6 + 2Au.

or,

3H2C2O4 + 2AUCI5 = 6CO2 -f 6HC1 + 2Au.

Oxalic Acid.

The gold precipitated by the ferrous sulphate, occurs as a dirty-looking brown powder; that by oxalic acid, as spongy or crystalline. The precipi- tate is washed, placed in a crucible lined with borax, melted, and poured into proper ingot.

Scraps, filings, and sweepings of gold alloys con- taining more or less of baser metals, as zinc, tin, lead, antimony, bismuth, iron, etc., are often refined by the dry method or roasting process, which consists of adding to the heated mass, either oxidizing, 19

218 Inorganic Chemistry.

chloridizing, or sulphidizing substances. lN"iter, (KNO3), is rich in oxygen, which it readily gives up when heated. It is, therefore, the substance usually employed as the oxidizer, and to whose power all the baser metals named, except tin, cheerfully submit. The latter metal, however, is easily chloridized by heating with mercuric chlo- ride (HgCl^). When sulphur is needed in the pro cess, it is furnished by the crude antimonium sul- phide (Sb2!S3). The disengaged sulphur forms sul- phides of the base metals present; the antimony alloys with the gold, and is afterward driven olf from the latter, by heating in an excess of air.

The chemical compounds of gold are neither nu- merous nor important.

Auric chloride^ AuClg, resulting by dissolving gold in aqua regia and evaporating the solution over the water bath, occurs as deliquescent, dark red crystals, soluble in water, ether, and alcohol ; of a styptic taste and escharotic and disinfectant properties, the latter effect being due to the ease with which it decomposes. It forms yellow double chlorides, with the chlorides of sodium, potassium and ammonium, asE^aCl, AuClg, called sodio-chlor- aurate.

Aurous chloride, AuCl, is obtained as a yellow- white substance, by heating evaporated auric chlo-

Gold, 219

ride. It is insoluble in water, and tends to change to free gold and auric chloride.

Auric oxide, AU2O3, is produced by digesting magnesia, MgO, in auric chloride. The magne- sium aurate that is formed, is decomposed by nitric acid, and on drying the residue, auric oxide is found aa a dark brown powder, easily decomposed by light and heat. It acts generally as an acid oxide, uniting with bases to form aurates thus

K2O + AU2O3 =: 2KAUO2

Potassium Aurate.

Ammonium aurate, obtained by digesting auric oxide in ammonia, is known as fulminating gold, a dangerous explosive, ^H^, AUO2.

Aurous oxit/e, Au 2 0, is a greenish powder. Pur- ple of Cassiush probably a compound of this oxide, with the tw^o oxides of tin, obtained by reaction between auric chloride and the two chlorides of tin, produced by dissolving gold and tin in aqua regia, and adding a weak solution of tin in hydro- chloric acid. Chloridation and oxidation of both metals take place successively. " Purple of Cas- sius " (Au20Sn305), as before mentioned, is used in coloring porcelain.

Materia Medica. — The mono-(aurous) chloride is not used in medicine. The tri-(auric) chloride is sometimes employed in obtunding sensitive den- tine dissolved in ether or alcohol. It acts like the

220 Inorganic Chemistry.

chloride of zinc, by dehydrating the gelatinous con- stituent of the dentine.

For internal administration the trichloride is usually combined with sodium chloride. It pro- duces an exhilarating influence on the nervous sys- tem, and is useful in hypochondriasis, functional impotence, etc., and in treating syphilis, as a sub- stitute for corrosive sublimate. Its antidote is the same as for the latter drug. The so-called bi-ch\o- ride of gold cure mixture for alcoholism and the opium habit, is said to contain no gold whatever, and is not regarded as belonging to legitimate therapeutics.

Dose. Auric chloride, 0.001-0.003 Gm. (gr. q\-2\)- Professor Grant Molyneux, of Cincinnati, has recently succeeded in developing a process of gild- ing porcelain teeth with gold, to represent fillings, facings, etc. The process consists essentially of compounding neutral auric chloride (AuClg), with Venice turpentine, and thinning the mixture with Artist's Dresden " thick oil," to the proper consist- ency. This is spread in desired position on the porcelain, and allowed to dry slowly over a water bath. It is then subjected to a red heat and, on cooling, leaves a pure gold surface, susceptible of a fine polish. • A similar process with neutral platinic chloride,

Gold, Platinum. 221

(PtCl^), instead of gold solution, has been found by Professor M. to be effective in forming a surface of platmum, as a successful backing on porcelain teeth, to which gold can be soldered without the usual intervention of platinum pins, making an attachment thus, as strong as the porcelain itself.

PLATINUM.

Symbol, At. Wt. Sp. Gr. Valency, Pt. 197. 21.5. II-IY.

Platinum, originally found in South America, is now principally supplied from the Ural Mountains and, to some extent, from Borneo and California.

It always occurs in the metallic state, in little grains or lumps, generally alloyed with gold, cop- per, and iron ; and its natural congeners of the platinum group, such as iridium, osmium, etc.

The methods employed for separating pure plat- inum from its ores are complicated. It is a blue- white metal, less brilliant than silver; not affected by the air, nor by any single acid. It combines directly with sulphur, silicon, arsenic, phosphorus, and chlorine ; is acted upon by fused caustic hy- drates, and dissolves slowly in aqua regia. It is malleable and ductile ; is possessed of considerable tenacity ; is about as hard as copper, expands uni- formly with glass or porcelain, and is relatively a

222 Liorganic Chemistry.

poor conductor of heat and electricity : it melts at the temperature of the oxyhydrogen flame.

On account of its infusibility, and insolubility in acids, platinum is used in various forms in the chemical laboratory, such as dishes, crucibles, stills, foils, wire, blow-pipe tips, etc.; also in the construc- tion of incandescent electric light lamps, as the neg- ative element in Grove's galvanic battery, as sustain- ing pins in porcelain teeth, as a basis for continuous gum plates, and in combination with felspar, in giving a required shade to enamel. In the form of platinum-foil, sponge, or better ^i\\\,j)latinum black, it possesses, in a high degree, the power of con- densing gases on its surface, the latter being able to condense 800 times its own volume of oxygen.

Platinum compounds are numerous and some- what interesting.

Platinic Chloride, PtCl4, is formed whenever plat- inum is dissolved in aqua regia; on evaporation it shows as a deliquescent red-brown substance, soluble it water, alcohol and ether ; it is used in chemical analysis in detecting alkaloidal bases, as 'ptomaines, etc. It unites with the alkali chlorides to form chloroplatinates, as 2KC1, PtCl4.

Platinous Chloride, PtCl2, is obtained when pla- tinic chloride is heated gently, until chlorine ceases to escape; it is a dark green powder, insoluble in

Iridium and Osmium. 223

water. It forms with alkali chlorides, chloroplati-

nites, as 2KC1, PtCl2.

Platinie oxide, PtOg, and platinous oxide, PtO,

and corresponding sulphides are known; also, a

remarkable series of compounds, formed by action

of ammonia upon platinum salts, called ammoni-

acal platinum compounds, as

p fNH3Cl ^^t^HgCl

Iridium and Osmium are heavier than platinum ; the sp. gr. of Ir being 22, and of Os, 22.5. Their atomic weights are near that of platinum, being 192.7 and 198.6 respectively. Iridium is not acted on by the air, nor is it soluble in aqua regia. It re- sembles polished steel, is brittle and very hard, and is often alloyed with platinum, in the form of wire and posts, for crown and bridge work.

The remaining congeners of platinum are Palla- dium, Rhodium, and Ruthenium ; their sp. gr. are respectively 11.4, 12, and 11.4; their atomic weights are 106, 104, and 103. They are of little relative importance. Palladium has the property of ab- sorbing hydrogen ; the latter thus, is said to be occluded.

224 Inorganic Chemistry.

CHAPTER XVIII.

ELECTROLYSIS.

Any compound liquid, capable of conducting the electric current, is an electrolyte, and will suffer de- composition by an electric current, in direct pro- portion to its conducting power.

One of the sources of electric development is by chemical action, and an arrangement by which the force is utilized thus, is called a galvanic, or voltaic battery. Galvanic batteries are constructed of vari- ous substances, and in various forms : one principle, however, obtains in all, viz., unequal chemical ac- tion on conductors, in the exciting liquid. The simplest conception of a galvanic battery, may con- sider its construction as consisting of the metals, zinc and copper, immersed in dilute sulphuric acid; the zinc and copper are acted upon une- qually by the acid, zinc more than copper; zinc is, therefore, electro-positive to copper, and the lat- ter becomes electro-negative. Electricity developed at the zinc plate, is called positive; that at the cop- per plate, ne^a<ii;e. Positive electricity passes /rom the zinc through the dilute sulphuric acid, and is

Electrolysis. 225

collected at the negative plate ; so that if conduct- ing wires be attached to the metals, the wire in connection with the copper will conduct positive electricity, and the one in connection with the zinc will be the negative conductor.

The extremities of these wires, or rheophoies {electrodes), are denominated poles ; or, positive pole and negative pole, respectively. When the con- ducting wires are in contact, or another conductor is interposed between them, the circuit is closed; otherwise the circuit is broken.

Other forms of battery, than the one described, are common. The bichromate of potash battery consists of the same materials, except it has carbon instead of copper for the negative element, and a solution of potassium dichr ornate mixed with the dilute sulphuric acid. The action of the acid on the zinc, as is well known, sets hydrogen free, which accumulates on, or polarizes, the negative plate, greatly interfering with the continuance of the current. The solution of the potash salt, is changed to chromic acid, which takes up the hydro- gen, thus preventing the polarization referred to.

The liquid in such a battery consists of water, 1000 CC (fGm), = (2.11 pints), sulphuric acid, 350 CC = (11.85 f.^), potassium dichromate, 230 Gm. (7 §). Dissolve the latter in boiling

226 Inorganic Chemistry.

water, 675 CC (1.36 pints), and when cool, add to the acid mixture.

The jpoles of the battery, when employed for the purpose of mere analysis, are usually tipped with platinum; and when these poles are immersed in a compound liquid^ capable of conducting the current from pole to pole, decomposition of that liquid will ensue. The chemical affinity, i. e., the attraction between the radicals of the molecules of which the liquid in question is constituted, will be overcome by the electric force, at the surface of the poles, the intermediate portion of the liquid being apparently unaffected. The following arrangement of the molecules of water, when under the influence of, the electric current, will serve as a sufficient exam- ple, for the process of electrolysis in general :

Ihh} Ihh} Ihh} \Hh} IHh} iKH/HH- The sign -|- in the above diagram, represents the positive pole of the battery, and the sign — the negative pole. It will be observed that free oxygen appears at the positive pole, this element is there- fore electro-negative to hydrogen ; and as hydro- gen appears at the negative electrode, it is positive to oxygen. In this way, the electric status of each of the several elements is relatively determined.

Oxygen is the most electro-negative of the ele- ments ; it must therefore be placed first, in the fol-

Electrolysis. 227

lowing comparative series. The other elements are, severally, electro-negative to those which fol- low them, and electro-positive to those that precede them.

Electro-negative.
0	B	Sn	Ba
s	C	Pb	Li
:n"	Sb	Co	Ka
F	Si	iN-i	K
CI	H	Fe	Eb
Br	Au	Zn	'Cs
I	Pt	Mn	Electro-positive,
Se	Hg	Al
P	Ag	Mg
As	Cu	Ca
Cr	Bi	Sr

It will be further noticed that the non-metallic elements, as a class, are electro-negative, while the metals, comparatively, are decidedly electro-posi- tive. The rarer elements are, for the most part, ignored in the above classification.

The liquid state is essential to an electrolyte; the thinest film of ice is sufilcient to arrest the elec- tric decomposition of water. Mere solution, or fusion by heat, will accomplish the object. But all Hquids are not electrolytes; water itself, when pure, is not a good conductor of the current, and therefore suffers only slight decomposition, even by a powerful battery ; whereas, if it contains a

228 Inorganic Chemistry.

very small proportion of sulphuric acid, it is ren (lered a good conductor, and submits readily to the process of electrolysis. Alcohol, ether, and numer ous other compounds of organic chemistry, and a few saline inorganic compounds, refuse to conduct, and thereby avoid decomposition.

When oxygen salts in solution suffer electro- lysis, they are at first divided into free metal and a negative radical. Sulphuric acid (hydrogen sul- phate, H2S04),is split up into free hydrogen, which appears at the negative electrode, and sulphione, SO4, which appears at the positive electrode. In the same manner cupric sulphate, CUSO4, splits up into metallic copper and sulphione, SO4 ; the SO4 loses an atom of oxygen, which escapes, and the res- idue, SO3, unites with water to become H2SO4. Sometimes the base of the salt is divided, so that free metal appears on the cathode, and metallic oxide on the anode. In case the metal is capable of de- composing water, as potassium, for instance, it will form a hydroxide, which will unite with the acid present, to reproduce the typical salt.

2K0H + H,S04 r= K5SO4 2II2O.

The amount of decomposition of each electro- lyte is perfectly definite, and is expressed for each by the value of its chemical equivalent. The equivalent value of water is 9 ; of hydrochloric

Electrolysis. 229

acid, 36.5 ; of potassium iodide, 166. Now, the same current passing through these electrolytes, will cause simultaneous decomposition of 9 parts by weight of water, 36.5 of hydrochloric acid, and 166 of potassium iodide, and so on, for other elec- trolytes as well, according to the same rule.

The process of electrolysis is subservient to many useful applications in the arts, such as elec- tro-plating with gold, silver, nickel, etc., and lately with iridium. In the making of electrotype^ by which the copper from cupric sulphate is deposited in the impression of the type, set up in the usual way, forming a coherent matrix for a permanent duplicate cast. Fac similes of engraving plates, medals, casts, etc., are obtained in this manner, and the wonderful invention of photo-gravure de- pends on this process of electrolysis.

For plating surfaces with silver .or gold, the cya- nide of the metal, obtained by reaction between silver chloride, AgCl, or gold trichloride, AuClg, and solution of potassium cyanide, KC!N", is the usual electrolyte.

A recent application of this process consists in the deposition of silver, on plaster models of the maxilla, for base-plates for artificial teeth. The plaster is covered \yith graphite, which serves as a conductor, outlining the size of the phite needed.

230 Inorganic Chemistry.

This is attached to the negative pole of the battery, and metallic silver to the positive pole. The latter is dissolved, more or less, by the influence of the electric current, thus keeping up the strength of the liquid, while the liquid itself, AgC^, in solu- tion, is decomposed, the silver going to the nega- tive pole until the required thickness of the plate is obtained. Then, by an analogous process, the silver plate receives suflacient deposition of gold to render the finished base all that may be desired for the purpose.

In all cases the article to be plated must be in connection with the negative pole, inasmuch as the electro-positive radical (metal), of the electrolyte, is set free at the negative electrode. The positive radical always appears at the negative pole, and the negative radical at the positive pole.

Storage batteries are plates which become polar- ized by receiving, on the prepared surfaces, elec- tro-deposition of certain substances. These sub- stances undergo further chemical change by being placed in a liquid able to act chemically on them, by which a secondary current is pro- duced. For example, if a lead salt be decomposed by electrolysis, metallic lead will be deposited on the cathode (negative pole), and lead dioxide, Pb02,onthe anode (positive pole). When plates

Electrolysis. 231

thus prepared are placed in dilute sulphuric acid aud properly connected by outside conductors, a cur- rent, reverse from the original, is developed by the resulting chemical change ; the lead becomes oxi- dized and the lead dioxide is reduced. In the ma- jority of cases hydrogen and oxygen are the polar- izing agencies, and thereby prove once more that force, like the " coon, may be caught a coming or a going:"

The Faradic current is an induced, interrupted current, produced by wrapping around a hollow cylinder of wood, thick, insulated copper wire, the primary coil; the secondary coil, made of thinner wire, is wrapped around the insulated first coil. The hollow cylinder contains a bundle of soft iron wire, which acts as a magnet, when a current of electricity is passed through the inner coil. Near the end of the soft iron wires there plays a bar, also of soft iron, regulated by a spring, the latter being in electric connection with the primary coil. The current passing through the primary coil, in- duces a secondary current in the outer coil, and in the opposite direction ; the soft iron bundle is magnetized by the current at the same time, and attracts the soft bar of iron, whose removal thus, breaks the current. In consequence of the break,

232 Inorganic Chemistry.

the bundle of iron is demagnetized, permitting the iron bar to assume its former position, which occasions a repetition of the phenomena, so long as the current is supplied. The induced current is necessarily a make and break, or, to and fro current, the stronger shock being received from the break.

Periodic Law, 233

CHAPTER XIX.

PERIODIC LAW.

The Periodic Law. — From the very earliest his- toric times, the theories advanced in regard to the ultimate nature of matter, possessed a peculiar charm; The discovery of oxygeu by Priestly, in 1775, lent a fresh impetus to these studies.

Guyton de Morveau, in 1782, suggested the first idea of systematic chemical nomenclature, followed by Lavoisior, who elaborated the idea so fully, that the present system of chemical nomenclature and notation may be considered, with a few improve- ments, to be Lavoisian. The atomic theory of Dalton, later, accounted satisfactorily for the mathe- matics of chemical reactions; and the relations be- tween the constants of the elements and their specific heats, and the electric behavior of the ele- ments themselves, seem to confirm the truth of Dalton's theory. Prout's hypothesis, in 1816, that the atomic weights of the several elements might be considered as exact multiples of the atomic weight of hydrogen (a theory, by the way, which is only slightly at variance with the present 20

234 Inorganic Chemistry.

accepted atomic weights, and which may be sus- tained by further corrections), was followed by the suggestion that possibly hydrogen was the " pri- mordial matter that forms the other elements, by successive condensations of itself."

In 1864 and 1870, Newlands and Mendelief, re- spectively, independently of each other, erected tables of the then known elements, beginning with those of the lowest atomic weights, and advancing regularly to the highest. They observed a natural grouping of the elements that appeared to bear some relation to their several atomic weights, and to their quantivalence when determined by their oxygen compounds; hydrogen alone, seeming to be especially isolated from the rest. Therefore, leaving hydrogen to itself, if we begin with the element of next lowest atomic weight, viz., monad- lithium, we find the progression to be as follows:

1. H, — -- _ — — _

2. Li7, Be9, Bll, C12, m4, 016, F19 —

3. Ka23, Mg24, A127, Si28, P31, S32, C135.5 If we study the position of the above elements, we

perceive that those to the left are metallic^ and those to the right are non-metallic, while the interme- diate elements, like silicon, possess chemical prop- erties intermediate between the two extremes. We notice that the line, commencing with Li, ends ab-

Periodic Law. 235

ruptly, with the acidulous fluorine, inasmuch as the element of next atomic weight, Na, is decidedly basic, and hence introduces another period. We notice, further, that the corresponding members of both periods have corresponding valencies, so that if placed in vertical columns, all those in the same column possess the same valency. The elements in each group, in the following table, arrange them- selves naturally in double columns, those on the same side resembling each other in chemical prop- erties. Each series is a small period ; series 1 and 2 the first large period ; series 3 and 4 the second, etc. R represents one atom of any element, as RO means one atom, united to one of oxygen, or RjO, two atoms, etc.

236

Inorganic Chemistry.

H

M

o

H

O

-^ H

o

(—1 Q O

1— 1 >		o 03		"2 1 O 00 IS	o 1-1 pi		o T-i cC CO Ol 1-1 u	1 1 1 1 1 1
>			5 a		r-l f-t CO		1 1
>	ffio P^05	O	CO a	OO V CO o 1^	1-1	1 ^ ' 00	05 CO P
>	in	1-1	r-( CO >	CO <	S!5	r-( 1-1 w 00 1-( 83 H	00 §
>	WO 05 03	i-t o		c^ o i> o> ON	00 O »— 1 ^ i-t rl q 0) CBO		o c^ Ph CO CO c^ H
1— I	CO lO	pq	<	GO	00 CO tH S3 B	CO I-H	i
-■	o 03	1 '^ 1 n	o o	SB u CO	CO w »-<		be w
1— J	JO 03			CO to OO	1—1 be CO eo I— 1 09
		00 CO	1-1 04	w*	io«o	t^OO	o> o	I— 1 1-1

Periodic Law. 237

The blank spaces in the foregoing table indicate the probably proper places of elements as yet un- known. Mendelief predicted the existence of two elements — eka- aluminum and eka-horon — which should fill the places now occupied by gallium and scandium respectively, and described the general physical and chemical properties of these elements in advance of their discovery.

In consequence of the periodic law, the sugges- tion is now accepted as truth, that "the properties of an element are a periodic function of its atomic weight." Those elements that unquestionably be- long to the same group, often present remarkable coincidences with reference to their atomic weights. Thus, the atomic weight of sulphur is twice that of ox^^gen, and if the atomic weights of sulphur, 32, and of tellurium, 125, be added together and the product divided by 2, the result will be in the immediate neighborhood of 78, the atomic weight of selenium. Again, the atomic weight of phos- phorus, 31, and of antimony, 120, added together, give us the number 151, which is almost exactly twice 75, the atomic weight of arsenic. The sum of the atomic weights of chlorine, 35, and of iodine, 127, is 162, which, divided by 2, brings us suffi- ciently near the atomic weight of bromine, 80, as to appear something more than a mere coincidence.

238 Inorganic Chemistry.

CHAPTER XX.

SPECTRUM ANALYSIS.

In concluding the history of the individual ele- ments, as well as many of their binary compounds, it will not be inappropriate to allude briefly to the subject of "spectrum analysis."

When sunlight is passed through a prism, it is split up into what are arbitrarily called the " seven primary colors of the solar spectrum." The colors, however, of solar light, strictly speaking, are not confined to merely seven in number, but are mani- fested in infinite variety, each corresponding to a special ''wave length." Sunlight furnishes a con- tinuous band of light, broken by a great number of fine dark lines ; but if the light from incandes- cent individual terrestrial elements be dispersed by passing through a prism, it will be found that only a few colors are shown consisting of bright lines, which are characteristic only of the elements pres- ent in a state of luminosity, by which condition their spectra are exhibited.

The instrument for examining the light given ofi' by special substances, is called the " spectro-

Spectrum Analysis. 239

scope," and the process itself is called " spectrum analysis."

When cempounds of sodium are heated in a common flame sufficiently, the yellow light of so- dium will confer on the flame a yellow color. In the same way potassium compounds will cause the flame to assume a decided violet tint. If there be present in the flame both sodium and potassium compounds, the intense yellow sodium light will so overcome the purple potassium color that the pres- ence of the latter element, although, perhaps, in excess, will not be detected. If compounds of either one of these elements be examined by the spectroscope, the light of sodium will be indicated by two bright, slightly different shades of yellow, lines, so close together that ordinary instruments show them as one bright yellow line. The light of potassium will exhibit several bright lines, widely separated, varying in color from strong violet to red. Now, if compounds of both sodium and po- tassium be examined simultaneously by the spec- troscope, the peculiar yellow lines of sodium and the purple and red and intermediate lines of potas- sium will all appear distinctly, so that the presence of both elements in the substance undergoing ex- amination in this way can be ascertained with certainty.

240 Inorganic Chemistry.

The metals thallium, caesium, rubidium, in- dium, gallium, and others were discovered by this process.

Barium gives lines of light of several different colors, ranging from green to red ; strontium, bril- liant shades of red and two of blue; thallium, only one — a splendid blue line ; and calcium, quite a number of lines, the yellow predominating. The other metals also: gold, platinum, silver, iron, etc., may each be recognized by the peculiar bright lines belonging to their spectra. N"itrogen exhib- its a spectrum, mostly purple; and hydrogen one bright red, one green, and one blue line.

Liquids and solids, when heated to incandes- cence, exhibit continuous spectra. It is only lu- minous vapors that give discontinuous, bright line spectrums. To obtain this luminous vapor of those elements which require a higher tempera- ture for the purpose, than can be conferred by a Bunsen flame, the electric spark is employed, which in passing between two points of the metal in question, volatilizes a portion, or in passing through gases, as hydrogen, etc., heats them so intensely as to enable them to give off the peculiar light characteristic of each.

The spectrum of the sun, when examined by means of the spectroscope, is found not to consist

V.

Spectrum Analysis. 241

of an absolute continuous band of light, ranging from red to violet, but is seen to be interpersed by hundreds of darJ{ lines, and these lines are observed to correspond in exact position to the bright lines in the spectra of terrestrial ele- ments.

This coincidence in the position of the dark so- lar lines with the well-known bris^ht terrestrial lines, led to the assumption that the dark and bright lines were produced by the same incandes- cent elements. Later experiments proved such as- sumption to be a fact. The brilliant lirne light thrown on the field of the spectroscope shows a continuous band of light similar to that of the sun. If, however, the sodium flame be interposed between the lime light and the spectroscope, the continuous spectrum will show a double dark line corresponding to the bright lines of sodium alone. The conclusion is, tlierefore, reached " that the va- por of an element has the power of absorbing light-rays of the same wave length as those it emits." In other words, the luminous sodium va- por stops the light of the same wave length or color, proceeding from the brilliant lime light be- hind it. It is opaque to the colors of its own kind, and allows the rest to proceed.

21

242 . Inorgayiic Chemistry.

The physical condition of the sun is at once in- dicated by these experiments of KirchoiF. It con- sists of a central incandescent liquid or solid body which reverses the light of the luminous vapors of the various elements in its own photosphere, changing the otherwise bright lines into dark lines, and these dark solar lines, corresponding in posi- tion to familiar terrestrial bright lines, prove the existence of the vapor of certain elements in the atmosphere of the sun, with as great a degree of certainty as any other question in physical science.

Oxygen, hydrogen, iron, nickel, cobalt, manga- nese, calcium, strontium, barium, chromium, mag- nesium, sodium, copper, titanium, aluminum, lead, cerium, cadmium, and uranium, have been identi- fied as solar elements. The planets give the same lines as those of the sun, as they shine by reflect- ing his light.

Similar methods of observation prove the fixed stars to be self-luminous suns. Many well known elements have been recognized in the star Alde- baran, and some also not as yet detected in the sun, as bismuth, antimony, mercury, and tel- lurium.

The true nebulce are ascertained to consist of masses of glowing gas, inasmuch as they give

Spectrum Analysis. 243

bright lines, indicating only, with certainty, the presence of hydrogen, a fact which seems to prove the nebular hypothesis^ and also the evolution of the various kinds of matter from one primordial element.

PAR.T THIRD.

ORGANIC CHEMISTRY.

CHAPTER I.

INTRODUCTORY REMARKS.

There is but one science of chemistry. Its di- vision into inorganic and organic, is simply one of convenience.

It was formerly supposed that the production of organic chemical compounds was restricted to the influence of vital force in the bodies of plants and animals. There is now, however, no boundary line between the two divisions, inasmuch as many organic compounds can be produced synthetically from inorganic materials, and many others, such as indigo, carbolic acid, etc., may be obtained by artificial means. But nevertheless, the practical source of organic compounds is from substances of animal or vegetable origin, so that those who erected organic chemistry into a separate science really builded better than they knew, by present- ing a division most convenient for the separate (244)

Introductory Remarks. 245

consideration of the chemical nature of carbon and its relations to the other elements.

Organized structures, that is to say, the various tissues of animal and vegetable bodies, can not be produced artificially. They are made up of chem- ical combinations which obey, in unison with nat- ural affinities, the governing power of vitality. When vitality ceases, these tissues undergo resolu- tion toward the formation of simple chemical com- pounds, unless their identity is preserved by im- mediate antiseptic treatment. When subjected to a high temperature, with access of air (oxygen), they are resolved at once, principally into H2O and CO2 ; and if subjected to destructive distillation^ volatile and liquid substances are given off, leaving a residue consisting of the charcoal variety of car- bon ; and finally, if left exclusively to nature's processes, decay supervenes by the agency of micro- organisms; rapidly or slowly, according to the na- ture of the substance, and its exposure to moisture and certain temperatures.

Spontaneous disorganization of substances, rich in nitrogen, is called putrefaction. They give off compounds of an unpleasant odor, consisting largely of ammonia and its derivatives ; whereas those bodies of a non-nitrogenous composition, losing their identity thus, are said to undergo fer-

246 Organic Chemistry.

mentation. In the latter case, the compounds re- sulting are mainly devoid of unpleasant odors.

There is no essential difference in the nature of the disorganization in those processes termed as putrefection, fermentation, and eremacausis, except in so far as the substances involved differ in chem- ical composition ; but the part played by micro-or- ganisms in the phenomena of changing complex bodies into simplar forms, is as yet undetermined, and would be out of place in a work of this kind, even if we had fixed theories on the subject. It will, therefore, be sufficient to remark in this con- nection that micro-organisms are of various kinds, and possess various functions. Some kinds of mi- cro-organisms, the saprogenic, will affect changes only in nitrogenous material, and even here, there are many species of the useful pests, which divide the process of putrefaction into several well marked stages. This fact also obtains in fermentation. Juices of various fruits, such as apples, etc., freely exposed to the air and proper temperatures, un- dergo changes finally resulting in alcohol (cider),

and this, if left to itself, by the agency of a special

*

micro-organic germ or ferment (the microdermi aceti), will change into vinegar, otherwise known as acetic acid. In the same way, special germs, acting on different substances, induce individual distinc-

Introductory Remarks. 247

tions ill fermentation, such as lactic, butyric, etc. In a given culture (decomposable substance), arti- ficially prepared, as solutions of the carbo-hydrates, lactic acid will result, by the influence of quite a number of different bacteria, some of them known as pathogenic (disease-producing), and others as non-pathogenic.

The tendency of fermentation is to produce acids; of putrefaction, to produce alkalies. In the latter case, as already alluded to, ammonia and its deriva- tives, the amines and amides are characteristic, together with exceedingly poisonous and non-poi- sonous diffusive ptoma-ines, or animal alkaloids, resembling in their chemical nature, well-known vegetable alkaloids, such as strychnine, atropine, morphine, etc.

If the substance undergoing transformation by bacterial influence, be composed of both fermentive and putrefactive materials, then both acid and alka- line products will occur. The fluid contents of the a-verage human mouth, consisting of normal saliva, mucus, and remains of various kinds of food, af- ford an excellent example of a heterogeneous cul- ture, and as more than twenty different kinds of bacteria have been detected in the oral cavity, it is easy to realize that in such a state of affairs, chemi- cal riots will be the rule ; acid fermentation, tend-

248 Organic Chemistry.

ing to destroy the structural integrity of the teeth, and alkali fermentation (putrefaction), tending to induce an inflammatory condition of the softer tis- sues of the mouth, oftentimes accompanied by swellings and general septicaemia, the latter symp- tom owing probably to the resorption of the poi- sonous ptomaines.

As counteracting influences opposed to the above conditions, we have the means of killing the mi- crobes direct, by the employment of germecides, and by disinfection, which destroys the infectious mat- ter, and at the same time changes the physical, or chemical, nature of the culture, so that it can not serve any longer as suitable soil for microbic propa- gation. Antisejptics applied to the part, and con- tinued, after disinfection, will prevent a recurrence of the fermentive process.

Germicides 'per se, are of little value as medicines, so long as the culture remains intact, for, as we may readily believe, the presence of living germs of the common forms of both phases of fermentation is practically universal. Disinfection, therefore, is the Samson upon which the dental surgeon should rely, followed by the exhibition of antiseptics, to prevent a return of the disease.

The terms disinfectants and antiseptics, are often improperly used indiscriminately; and although it

Introductory Remarks. 249

is impossible to draw a sharp line of demarcation between these two classes of remedies, inasmuch as some members of each (like silver nitrate, salicy- lic acid, etc.), act more or less, in both capacities, we will presume to draw a few distinctions between them, which, on account of necessary brevity, will no doubt appear rather too dogmatic.

It is a question yet in doubt as to whether full grown micro-organisms, bacteria, exist in all infec- tious matter; their absence therein does not, there- fore, disprove the bacterial genesis of disease, or of their necessary presence in inducing chemical changes in the organized tissues that have lost wholly, or in part, the governing power of vitality. Their spores can yet live in the excrementitious matter, and when planted in congenial soil, will sprout and grow into the characteristic bacilli of their kind. Poisonous ptomaines alone, when forced into healthy living tissues play an impor- tant part, not yet understood, in the production of acute diseases. It follows accordingly, that any means by which remaining bacteria, spores, and ptomaines can be completely destroyed, must be credited as belonging to the class of thorough dis- infectants.

Disinfection can be accomplished in various ways.

First, by mechanical means ; removing the infec-

250 Organic Chemistry.

tious matter beyond the sphere of possible repro- duction ("to the bottom of the sea").

Second, by extremes in temperature, especially a high temperature, which kills bacteria, and spores, and changes the chemical nature of the culture in which they thrive, and also the poisonous products of decomposition.

Third, by chemical means ; chemical action, as we know, causes complete loss of identity in the acting bodies, and where chemical changes take place in infectious matter, it necessarily loses its power of infection. Oxygen is involved in this form of disinfection more than all other material agencies combined. In the process oi fumigating, by burning sulphur, the freshly formed sulphurous oxide (SO2), deoxidizes the injurious organisms and compounds, by taking away some of their structu- ral oxygen, which change, of course, destroys their identity. On the other hand, such incontestible disinfectants as peroxide of hydrogen, potassium permanganate, chlorinated lime, chlorinated soda, etc., furnish active oxygen, which as stated under their several heads, burns up the infectious mate- rial, in the same way that nature's great disinfect- ant, ozone, accomplishes its peculiar function.

The removal of all infected matter in caries of the teeth, by instruments, is disinfection, Anti-

Introductory Remarks. 251

septic measures are then adopted, by proper meth- ods of filling the cavity, to ^prevent a return of the destructive phenomena in that part of the tooth. Or complete removal of the contents in root canals by instrumental manipulation, is thorough disin- fection of the part, a labor requiring infinite care, and which is generally supplemented by aid of chemicals and a high temperature, followed by the insertion of antiseptics, as the phenols, iodoform, essentials oils, etc., in connection with the sealing qualities of the filling.

A healthy part does not need disinfection, but it does require antiseptic treatment, to prevent the development of disease. The judicious use of the tooth-brush, in a healthy mouth, is antiseptic treat- ment by cleanliness, tending to keep the parts therein in a healthy condition ; much alike in prin- ciple and object to the treatment of fresh meats by the use of the antiseptic, common salt. Wc might multiply examples indefinitely to prove our thesis, but the above brief remarks, we hope, will enable the student to appreciate the distinction that really exists between the two classes of remedies known as disinfectants, and as antiseptics.

252 Organic Chemistry.

CHAPTER II.

CARBON COMPOUNDS.

The four points of attraction possessed by the atom of carbon, furnish the basis by which organic compounds are classified. These compounds are made up, mainly, of carbon, hydrogen, and oxy- gen, but many of them contain niti'ogen, phos- phorus, and sulphur; also the haloid elements and various metals.

Methane, CH4, serves as the best prototype of organic compounds. As will be observed by its

formula, one atom of tetrad carbon — C — has its

I

valency of four, completely satisfied by union with the four atoms of monad hydrogen ; so that the saturated compound is not able to take up any more monad atoms, except by displacement of an equivalent number of the hydrogen atoms. In a previous chapter, however, we alluded to the fact that any dyad radical, elementary or compound, can enter into direct combination with a saturated compound, because the two units of combining power, belonging to the dyad, so act as to neutral-

Carbon Compounds. 253

ize one unit of the compound it enters, and intro- duce another, leaving the equivalency of the com- pound the same as before.

Consequently, methane may take up the dyad radical CHg" to form C2H6, as may be easily un- derstood by the graphic formulas.

H H H H

i I II

H— C H(CHJ+— C— (CH2) = H— C— C— H {C^H.')

I I II'

H H H H

Methane Methene. Ethane.

On the other hand, methane, CH^, under cer- tain circumstances, may lose two of its hydrogen atoms, resulting in the development of the above dyad radical methene; and ethane, C^Hg, may lose two of its hydrogen atoms, and a new series of hydrocarbon compounds be thus obtained.

The following table of some of the hydrocar- bons, arranged and named by Hoffman, will enable the student to appreciate the above statements :

254

Organic Chemistry.

CH

CH.

Methane.	Methene.			■
C,He	C,H,	(^2^2
Ethane.	Ethene.	Ethine.		^.
C^3^8	^sHg	C3H4	C3H,	^'
Propane.	Propene.	Propine	Propone.	s
C4H10	C4HS	C4H,	C4H4 C4H2
Quartane.	Quartene.	Quartine.	Quartone. Quartune.
C5H12	C5H10	^5^8	^5^6 ClgH^ C5H2	\
Quintane.	Quintene.	Quintine.	Quintone. Quintune.	3
^&^1A	^6^12	^6^10	CgH, C,H, CeH„etc.	^
Sextane,	Sextene.	Sextine.	Sextone. Sextune.

Greek prefixes are generally preferred; thus pentane instead of quintane; hexane instead of sex- tane; heptane instead of septane, etc.

Now, by reference to the table, it will be noticed that the compounds in each vertical column differ successively from each other, by CH2 ; and those in each horizontal line, differ from each other suc- cessively by H2. Those in each vertical column, form each a homologous series, and those on horizon- tal lines, an isologous series. The latter are also called the monocarbon, dicarbon, tricarbon, groups, etc.

The lowest member of each homologous series^ leaving out a few which are not known to exist, is

Carbon Compounds. 255

presented below as far as the eighteenth, together with the general formula for each ;

Series. Lowest Member. General Formula.

1 CH4 CnH2U+2

2 C2H4 CnH2n

3 C2H2 CnH2n— 2

4 C5H6 CnH2n— 4

5 CgHg CnH2n— 6

6 CgHg CnH2n— 8

7 CgHg CnHgn— 10

8 CjoHg CnHsn— 12

9 C12H10 CnHan— 14

10 C14H12 CnHan— 16

11 Cj^Hjo CnH2n— 18

12 Cj^H,^ CnH2n— 20

13 CjeHjo CDH2n— 22

14 CjgHjg CnH2n— 24

15 C20H14 CDH2n— 26

16 CnH2n— 28

17 C22H14.... CnH2n— 30

18 C26H20 CnH2n-32

Cn means any number of carbon atoms, and H2n + 2, twice as many hydrogen atoms and 2 over; CnH2n, twice as many hydrogen atoms as as carbon atoms; CnH2n — 2, twice as many hy- drogen atoms as carbon atoms, minus 2, etc.

The hydro-carbons in the first vertical column

256 Organic Chemistry.

on page 254 (series CnH2n-|-2), are all saturated compounds ; those in the second column (series CnHgn) are dyad radicals, capable of uniting with 2 atoms of chlorine without displacing hydrogen, as in ethene chloride, C2H4CI2 ; those in the third column, are triads, etc.

The first members, as methane, CH4 ; ethane, C2Hg; propane, CgHg ; ethene, C2H4 ; ethine, C2H2, etc., are gaseous at ordinary temperatures, and increase in density in regular ratio, with each additional CH2.

The higher members, of which C35H72 is the extreme, are solid ; while the intermediate mem- bers, such astetrane (quartane and butane), C^H^o ; decane, O^qR^.^, etc., are liquid. The boiling points of the liquid hydrocarbons increase regu- larly, but in diminishing ratio with each increase of CH2. Thus:

Tetrane, OJ^^^, boils at 0° (32F) Increase.

Pentane, C5H,2, " '' 38° (100) 38 C.

Hexaiie, C^R^^, " " 69° (156) 31

Heptane, C^Hig, " '' 98° (208) 29

Octane, CgHig, " '' 124° (255) 26

Carbon Compounds.

257

CHAPTER III.

CARBON COMPOUNDS.

The hydro-carbons, containing an even number of hydrogen atoms, may exist free. Many of them are known.

Hydro-carbon radicals, containing an uneven number of hydrogen atoms, do not exist free, but nevertheless maintain their integrity through oper- ations of decomposition and recomposition, just like the elements themselves, ranking as units, like the atoms of hydrogen, oxygen, gold, etc. They are derived from the hydro-carbons of even equiv- alency, in the same way that hydroxyl (HO), is derived from H2O. A few of the most common occurrence are subjoined:

CH

Methane.

Ethane.

C3H,

Propane.

Butane.

CH3

Methyl.

CJI5

Ethyl.

C3II,

Propyl.

cjr,

Jiutyl, etc.

CH2''

Methene,

C2H4"

Ethene.

CsIIe"

Propene,

CH'^'

Melhenyl.

C2H3'''

Ethenyl.

Fropenyl.

The final syllabic yl indicates a compound radi- 22

258 Organic Chemistry.

cal of uneven valency; so also certain rajilicals of both uneven and even valency, not derived from saturated hydrocarbons, as nitryl, NO^, carbonyl, CO, etc. The derivation of certain other radicals suggest their names ; thus from ammonia, ^Hg, by abstraction of one atom of hydrogen, is derived amidogen, NHg ; and by taking away two atoms of hydrogen from Nllg, is derived the dyad radical, imidogen, I^H''. Cyanogen (meaning blue), C^ (quasi symbol Cy), when free, is formulated as C!N"-C^, analogous to the molecule of chlorine, Cl-Cl, and when acted upon by a metal, as Kg, re- sults according to the equation,

K^ + Cy, = 2KCy

Potassium. Cynogen. Pot. Cyanide.

Just like a molecule of chlorine on a molecule of potassium, Kg + Clg, = 2KC1. The radical cya- nogen, CN, (Cy) is one-half the molecule of free cyanogen, just as the atom of chlorine, CI, is the radical of the free molecule of chlorine, Cl-Cl.

These latter compound radicals, carbonyl, nitryl, amidogen, imidogen, and cyanogen, are not strictly classified as organic, but are interesting in this connection, inasmuch as they enter largely into the formation of many accepted organic com- pounds.

The hydrocarbon radicals, however, such as

Carbon Compounds. 259

nictliyl, nietlienyl, ethyl, propyl, etc., are the ones that should engage our especial attention in study- ing organic chemistry. They behave, as before remarked, similarly to the atoms of the elements, and like the latter, are relatively electro-positive or electro-negative. With 0, CI, etc., they are electro-positive, as in ethyl oxide, (0115)20, and ethyl chloride, CH5CI ; and electro-negative, in metallic salts, as in lead ethide, rb(CH5)2.

From them, all well defined organic compounds maybe presumed to be formed, most of which may be assumed to be derived from the following members :

1- Alcohols. — Formed by the union of hydro- radicals with hydroxyl. CHg,OH C2H5,OH C2H4(OH), C3H5(OH)3

Methyl Alcohol. Ethyl Alcohol. Ethene Alcohol. Propenyl Alcohol.

Alcohols are really hydroxides^ analogous to the hydroxides of metals. Thus sodium hydroxide, NaOH, calcium hydroxide, Ca(0II)2: The first is similar in composition to methyl and ethel alco- hols, and the latter to ethene alcohol.

2. Oxygen Ethers. — Are formed after the water type, 11 — 0 — U, and consist of hydrocarbon radi- cals and oxygen. Common ether is ethyl oxide, 0211,5^0 — 02115. A mixed ether contains more than one hydrocarbon radical ; methyl-ethyl ether, OH 3 — O — Ogllg, is a mixed ether.

260 Organic Chemistry.

3. Haloid Ethers, are compounds containing hydrocarbon radicals, and a haloid element; chlo- roform, CIICI3 is a haloid ether, made up of the trivalent hydrocarbon radical methenyl, and three atoms of univalent chlorine.

Iodoform CHI3, and "Dutch Liquid" C2H4CI2, are also examples of haloid ethers.

4. Organic Acids, may be defined as -oxygenated hydrocarbon radicals and hydroxyl, as acetic acid C2H3O, OH, formic acid CHO, OH, lactic acid, C3H5O2, OH. The molecule of an organic acid, therefore contains at least two .atoms of oxygen ; they may also be regarded as being produced by union of a hydrocarbon residue and the univalent

I

radical carhoxyl COOH, graphically 0=0 — 0 — H, thus acetic acid CH3COOH ; formic acid, H, COOH ; lactic acid C2H5O, COOH. Where but one group of carboxyl is shown, as in the above, such acid is monobasic^ giving up only the hydrogen of carboxyl

to a metal ; and when two such groups are shown,

CH,— COOH,

as in succinic acid, | it is dibasic.

CH2— COOH,

5. Esters, are ethereal salts, formed by hydro- carbon radicals, and organic or inorganic acid radicals, for example ethyl acetate, C2H5, C2H3O2. Ethyl alcohol and nitric acid, yield the ester, ethyl nitrate, and water.

C2H50H+HN03=C2H5N03+H,0.

Carbon Compounds. 261

6. Aldehydes, meaning less hydrogen than is contained in the corresponding alcohols, are com- pounds, intermediate between alcohols and acids. That is, they contain less hydrogen than the alcohol, and less oxygen than the corresponding acid, and are derived by the removal of hydrogen from the alcoliol, by oxygen, all of which may be understood by the empirical formulas :

C^HgO + 0 = C2H4O + H2O.

Ethyl Alcohol. Aldehyde.

C2H4O + O = C2H4O2.

Aldehyde. Acetic Acid.

An aldehyde can be converted into an alcohol, but an acid can not.

7. Ketones are derived from aldehydes, by replac- ing one atom of hydrogen by an alcohol radical.

Acetone.

or they may be considered graphically as two univalent radicals, held by bivalent carbonyl CO. The ketones are quite numerous, of which acetone is the best prototype. Acetone itself, may be re- garded as dimethyl ketone CH3

0=0

CH3. There are also diethyl, and ethyl-methyl, etc., ketones.

8. Amines, are derivatives of ammonia by sub- stitution of hydrogen, by hydrocarbon radicals.

262 Organic Chemistry.

,H fC.fi, fC^Hj fC^H,

Ammonia. Ethylamine. Diethylamine. Triethylamme.

The amines are numerous, and are mostly basic in character. Where all the hydrogen is removed, the trivalent radical IT is evidently capable of taking up three univalent radicals as above, or one triva- lent radical, as below :

Methenyl Nitril. Ethenyl Nitril.

These trivalent nitrils are not basic ; they are all neutral, except the first, which is acid, capable like HCl, of exchanging its hydrogen for a metal, and may therefore be regarded as composed of hydro- gen and the univalent radical cyanogen, I^CH -= HCK

Methenyl Nitril. Hydrogen Cyanide.

(Hydrocyanic Acid).

ITC2H3 = CH3CK

Ethenyl Nitril. Methyl Cyanide.

Analogous to the amines, are the arsines, stibines, and fhosjMnes.

9. Amides are analogous to the amines in com- position, except they contain acid radicals, instead of hydrocarbon radicals. Those which are made up of a bivalent acid radical, and imidogen, are called imides.

C2H30,KH2 C4H4O2NH

Acetamide. Succiuimide.

Carbon Compounds. 26B

CHArTER IV. CARBON COMPOUNDS.

When two or more corapoiinds can be represented by the same empirical formuhx, they are said to be isomeric. The difference in the chemical and physi- cal nature of isomeric bodies, is due to the difference ill the relative position, or arrangement, of the atoms in the molecule, and it is upon this fact that the somewhat startling innovation o^ stereo-chemistry is founded.

True isomeric bodies are those which have the

same kind and number of atoms, not grouped into

special compound radicals. These isomers react

similarly, by the influence of the same reagents.

There are many examples of this class, two of

which will suffice :

H

H I

I H-C-HH • H-C-H I I

H-(^-n H— C C-II

H-O-H I I

H-C-H H-C-HH

H-C-H H— 6— H

i

H

Pentane. Isopentane.

264 Organic Chemistry,

Metameric isomers, are those bodies which have the same composition, but differ greatly in their transformations under similar circumstances ; as an example, the formula C3Hg02 represents methyl acetate, ethyl formate, and propionic acid, two of which we subjoin graphically.

H3C

H3O H^

i

0-rC— 0— CH3 0=C— O— H

Methyl Acetate. Propionic Acid.

Polymeric compounds are those which have the same percentage composition but difier in molecu- lar weight. Examples of this class are found in the series, homologous with CH2:

Ethene (ethylene) C2H4.

Propene (propylene) C3Hg.

Tetrene (bytylene) C^llg.

Pentene (amylene) C^IIiq.

Several essential oils are isomeric with oil of turpentine, C^ qHj g ; and others are polymeric with the latter, having the formulas, C20H32 C3QH48, etc. All polymeric compounds, exhibit regular gradation in density, and boiling points, from the lowest to the highest.

Optical isomerism, possessed by similar com- pounds, is due, according to stereo-chemistry, to asymetric carbon atoms in each molecule.

Carbon Compounds. 265

The above examples of isomerism show the im- portance of rational formulas. The empirical formula of methyl alcohol, for instance, is CH4O. The rational formula is CH3OH. The formula C2H4N2O, expresses the number and kind of atoms in both ammoniuyyi cyanate and carbamide^ and might also be supposed to suggest the direct union of methane and nitrous oxide; but if each be for- mulated rationally, we can then have easy con- ception of differences in their chemical and phys- ical properties.

Ammonium Cyanate. Carbamide (Urea).

Ammonium cyanate can be prepared from inor- ganic sources. Its molecular transformation into urea by Wohler marked the lirst artificial produc- tion of an organic compound.

23

266 Organic Chemistry,

CHAPTER V.

PARAFINS, SERIES CnH2ii+2.

The formulas of the first members of the me- thane series of hydrocarbons, suggest asymmetrical arrangement of the atoms of hydrogen, in con- nection with the atom of carbon. The four points of attraction belonging to the latter, are properly represented by the four solid angles of a tetrahe- dron, to each of which is attached an atom of hy- drogen in methane. In the next member, ethane, containing two atoms of carbon, one point of at- traction belonging to each, is united to the other, leaving 3 points free to unite with hydrogen, and so on with the next member, propane, where the middle carbon atom can satisfy only 2 of hydro- gen. Such stereo arrangement can not be repre- sented on a plane surface, except feebly in per- spective, but the following diagrams will ade- quately express the mathematical values of each compound :

	Parajins, etc.			267
H	H		H
H C H H Methane.	H C H	H-	-0- -C- -C- n	-H
H C H H Ethane.	H- H-	-H -H

Propane.

Modifications of these molecules are probably impossible, and therefore there are no isomers of methane, ethane or propane, but with the next member, butane, C4H1Q, it is possible to write the graphic formula in at least tw^o w^ays ; and it is a fact that two kinds of butane are recognized :

H

H H-C— H

I I

11— C C— H

H ii_i_H

Isobutnne.

As the individual hydrocarbons, of this or other series, increase in the number of carbon atoms, it is evident that many modifications are possible, and a corresponding number of isomers may be produced. A mathematical limit, however, in each case, is also evident.

268 Organic Chemistry.

The methane series of hydrocarbons are found in petroleum. The first four members, are gases, the fifth a light liquid, and so on, increasing in specific gravity by each increase in CH2 ; the latter mem- bers, being solid. Parafin itself is a mixture of the higher members.

Methane, CH^, as well as each of the other satu- rated hydrocarbons is formulated rationally as a hydride, to indicate the presence of a compound radical which retains its identity in many reactions. For example, methyl hydride, CH3, H (methane), when acted on by chlorine forms methyl chloride CH3, CI. Ethyl hydride C2H5,H (ethane) simi- larly also forms, by losing an atom of hydrogen, ethyl chloride C2H5CI, etc.

By acting on methyl chloride, with excess of chlorine, the isologous radical methenyl, CH, is produced; this takes up, 3 atoms of chlorine, and methenyl chloride, chloroform, CHCI3, results. Chloroform however, is commercially prepared, by distilling together, either methyl, or ethyl alcohol, and bleaching powder. 2C2H60+5CaCl202=2CaC03-f2CaCl2+Ca(HO)2+4H20+

Alcohol.

2CHCI3. Chloroform.

Chloroform is a haloid ether, of an agreeable odor. -It is a colorless liquid, of specific gravity 1.52, and boils at 62° (143 F.). Its molecular

Parafins, etc. 269

weight as seen by formula, is, in round numbers, 120; its vapor density compared with hydrogen, is one-half its molecular weight, or 60, and as air is nearly 15 times as heavy as hydrogen, the vapor of chloroform is therefore about 4 times as heavy as air.

The purest chloroform is now made from chloral lu'drate. It possesses strong solvent powers on the diiFerent oils, camphor, caoutchouc, resins, the amines, and bromine and iodine. It is not inflam- mable; is freely soluble in ether, and alcohol, and sparingly so in water.

Materia Medica. — Chloroform has been a favorite anaesthetic from the period of its introduction in 1847, but on account of the many fatal cases which have occurred under its influence, it is being dis- carded more and more, in favor of ether. Its em- ployment alone, or in combination with other ansesthetics, in the simple though painful opera- tion of extracting teeth, is not regarded as legiti- mate practice by the highest authorities in our profession. It kills by direct heart paralysis, prob- ably due to the physical change which chloroform produces in the blood itself. The strong tendency to immediate coagulation of fresh blood, by outside experiments with chloroform, is at least suggestive.

270 Organic Chemistry.

Locally applied, chloroform is an irritant, and reduces painful impressions in the part ; it is also a good haemostatic. Taken internally it is em- ployed as an anti-spasmodic and anodyne.

Dose, 0.06-0.30 fGm. {y(i i-v).

For iuhalation 4. — 8 f Gm. (f^i-ij).

Iodoform, methenyl iodide, CHI3, is a haloid ether, analogous to chloroform, and, like the latter, is a derivative of methane. It is prepared by heating to a temperature of 40° (104F), an alco- holic solution of potassium iodide with bleaching powder. It occurs in small yellow crystals, some- what volatile, giving oii'an unpleasant saffron-like odor ; is insoluble in water, but is freely soluble in oils, chloroform, ether and alcohol.

Materia. Medica. — Iodoform is a typical anti- septic; applied to a disinfected part, it effectively prevents the development of both alkali and acid ferments. As a dressing to ulcerous sores, open and sloughing wounds, it is anaesthetic, and stimu- lates healthy granulations by preventing profuse discharge and consequent irritating sequelse.

As an antiseptic dressing in root canals of teeth, it is favored by many of our most eminent prac- titioners, notwithstanding its rather enervating odor. This single objection to iodoform is easily overcome by the addition of either one of several

ParaJinSj etc. 271

essential oils, which act both as adjuvans and cor- regens to its medicinal value.

The principle of the Blair apparatus, by which iodoform is vaporized by heat and forced into root canals, is a correct idea in therapeutics; ^. e., the thorough disinfection by the heat required to hold the vapor, and the immediate deposition of the sublimed iodoform, which fills the open spaces, and by its insolubility and iodic action on micro- organisms, prevents a return of the disease. A thermometer attached to the apparatus would be desirable — together with other improvements — as the compound easily decomposes by heat into free iodine and hydrocarbons, principally ethene, C^H2, 2CHI3 + q. s. Heat = 1q + C,H2.

Iodoform is neither a local nor general irritant. Internally exhibited, it is antiseptic, anodyne, stimulant, alterative, and tonic. It is not loholly decomposed in the body, as its odor can be de- tected in the blood and the several tissues.

Dose, 0.06—0.012 Gm. (gr. i-ij)

Bromoform, methenyl bromide^ CIIBrg, is another haloid ether, analogous to the foregoing com- pounds, but is not important. To show these bodies, as derivatives of methane, the simplest possible organic chemical hat-rack is erected :

272 Organic Chemistry.

H CI I Br

H-C— H H— C— CI H-C-I H— C-Br

i

H CI I Br

Methane. Chloroform. Iodoform. Bromoform.

Alcohols, etc. 273

CHAPTER VI. ALCOHOLS, ETC.

Methyl Alcohol, CH3OH, is known as wood spirit, obtained by the dry distillation of wood, and may also be produced by direct synthesis; it is a constituent of oil of winter-green from gaultheria procumbens. It is a colorless mobile liquid, of spe- cific gravity 81, which boils at 66° (150F), and is used as a substitute for ethyl alcohol in various manufacturing processes.

The alcohols are not necessarily similar in phys- ical properties to common alcohol. Some of them are solid, but all may be regarded as consisting of hydrocarbon radicals and hydroxyl.

They are called monatomic, when the molecule contains only one group of hydroxyl (OH) ; and they are known as primary^ secondary and tertiary, according as the carbon atom in combination with hydroxyl is also united to one, two or three other carbon atoms.

H rcH,

c<

H pjH

on

Methyl Alcohol. EthyfAlcohol. Propyl Alcohol

H ^^H

on i^on

274 Organic Chemistry.

If the hydrocarbon type of the alcohol be pre- served, there can be no modification of the first formulas; in other words, there can be no isomeric alcohols of these; but the higher members of the series, as butyl (tetryl, or quartyl), alcohol CJl^^O, etc., admit of three modifications, and form three insomeric alcohols, primary, secondary and ter- tiary.

f

rCH,CH,CH3

CH,CH3 rcH3

CH„ r. I CH,

CH3

c 1 c^— » c<;_

tOH I^OH I^OH

Primary. Secondary. Tertiary.

Primary alcohols of the methane series are con- verted into aldehydes by losing 2 atoms of hydro- gen, and then by oxidation into corresponding acids.

Secondary alcohols in losing by oxygen, 2 atoms of hydrogen, are converted into ketones; as second- ary propyl alcohol.

rcH3

(, I CH3 - H, = CH3 - CO - CH3

' H Minus. Dimethyl Ketone.

[oh

And

fCH2CH, (.ICH3-1I, = CH3-C0-C,H,

) H Minus. Methyl-ethyl Ketone.

Secondary Butyl Alcohol.-

Alcohols^ etc. 275

Ketones are CO, united to two univalent hydro- carbon radicals.

Tertiary alcohols do not yield either aldehydes, ketones, or acids, containing the same number of carbon atoms as do the alcohols themselves, but are split up into bodies which show a less number of carbon atoms. Thus, with tertiary butyl alcohol :

cJ ?S3 + o, = cn,o, + C,H,0, + H,0

OH

CHo Formic Acid. Propionic Acid.

The following table contains in empirical form- ulae, the known monatomic alcohols and corres- ponding acids, together with acids which have no known alcohol prototypes :

Z/l)

Organic Chemistry.

o

+

o <1 'p^

t- Pw^lnw '^n 00 I -co CO (M • Oi lO CO t^ CC 00

^ j^eiow zu. ,— I 'M Tif lo o • CO t^ 1^ t- 1^ 00

O

OOOOOI^CiCiOO Or— i-^COt^OlOiCOCO

"^^ "^O o ooooooooo

o CO CO Oi Ol O Tf

;:^ t^ Oi O CO lO CO

. d

• n^ O • • • • • Oi lO

• Ph oi t^ 00

! +j ! . ! . .

• 1; .....

^-OOOO

,_ O W O IM ■* «5 s^ to 00 ,-1 -H rH ^

l-H hM HH -J-l ^ HH HH >-Ih m CO -<i< m CO t~-

OOQOOOO

		O
	I^" .	^		^
	t^ .	CO
	ffi •	ffi
	o	:o
	_l	,_(
	Q .

GO

CO PJ

in CO

1:- O

c;i

a;

a;

Ethyl Alcohol^ etc. 277

CHAPTER VII.

ETHYL ALCOHOL, ETC.

Ethyl Alcohol, C2H5OH, is the active prin- ciple of brandy, rum, whisky, beer, ale, and wine.

It may be produced by synthetic processes, and by various reactions, but is practically ob- tained by fermentation of starchy and saccharine substances, such as the different grains, cane sugar, fruits, etc.

The mashed grain in aqueous solution, fer- ments by aid of the yeast germ, the starch being turned into glucose; a weak solution of alcohol is thus obtained.

Glucose. Alcohol,

This alcoholic solution is then distilled^ and the process repeated until about a 90 per cent alcohol is obtained. The water still remaining, is par- tially removed by distilling with quicklime; the product is then called absolute alcohol, a colorless liquid of sp. gr. 80, of a pungent burning taste and spirituous odor. Is boils at 78.5C and freezes at — 130.5C. Alcohol mixes with water in all propor- tions; is a solvent for various gums and resins, in

278 Organic Chemistry.

the making of medicinal tinctures, and is used in many chemical and manufacturing processes; it is also a valuable antiseptic against putrefaction and burns in the air, evolving great heat.

Proof spirit contains about 50 per cent of alco- hol : whisky, rum and brandy, from 40 to 50 per cent ; wines from 5 to 20 per cent, and beer, from 3 to 7 per cent.

Alcoholic or vinous fermentation will run into acetous fermentation, unless prevented by joas- teurizing, by heat or by bottling, or the use of chemicals.

C2H6O + O =: C2H4O + H2O

Alcohol. Aldehyde.

C2H4O + 0 = C2H4O2

Aldehyde. Acetic Acid.

AcET- Aldehyde C2H4O. This compound is the best known of its class, called aldehydes. They contain the group COH, and are intermediate be- tween the foregoing alcohols and their correspond- ing acids.

Acet-aldehyde, also formulated as acetyl hy- dride, C2H3O.H, is produced by oxidation of di- lute alcohol, and by several other processes. It is a clear liquid of sp. gr. 0.81, at 1°; of an ethereal suffocating odor, and mixes in all proportions with water, alcohol, and ether. With chlorine it forms acetyl chloride, CH3O.CI; with nascent hydrogen,

Ethyl Alcohol, etc. 279

alcohol; and with oxygen, acetic acid. It reduces metallic silver from a solution of the nitrate, and unites with the alkali metals, and with ammonia, to form solid compounds, C2H3O.NH4. Polymers of aldehyde are known, a doubling and trebling of the molecule, as C4Hg02, and C^H^<^0^, It is isomeric with ethene oxide and acts in many cases as the oxide of a dyad, under the name of alde- hydene.

Acetic acid, C2II3O2.H (in the dilute state, known as vinegar), is the most familiar of the acids corresponding to the methane series of alcohols. The first of this series of acids is formic acid, CHO2H ; next, acetic, and so on. With each ad- dition of CH2 they vary in their physical proper- ties, ranging from the light volatile formic acid, on to, and above, the 9-carbon molecule, where they become semi-solid, of waxy or greasy consist- ency; hence their general nsuney fatty acids. The best known of these higher acids, are palmitic, mar- garic, stearic and mellissic.

Acetic acid is generally obtained by fermenta- tion (oxidation) of wine, cider, etc., or from the alcoholic mash from which spirit is distilled. When pure, it is a colorless liquid which, at a tem- perature of 18 (64.5F), freezes into a solid ; hence the name, glacial acetic acid. It mixes in all pro-

280 Organic Chemistry.

portions with water, alcohol, and ether, and is mon- obasic, forming, with metallic bases, salts called acetates^ and with alcohol radicals, such as methyl, ethyl, etc., it forms esters or compound ethers ; in these cases, giving up one atom of typical hydro- gen to make room for the base, just like similar reactions with the inorganic acids. Acetates of iron and aluminum are used as mordants in calico printing. Verdigris is copper acetate ; and sugar of lead is plumbum acetate, Pb (0311302)2 + ^ Aq. The latter compound is of great value to the • chemist, and possesses soothing astringent medic- inal properties. Oalcium carbonate will dissolve in acetic acid (even dilute) forming calcium acetate

Ca(C,H302)2.

Compound ethers, formed by the fatty acids with the alcohol radicals of the methane series, are becoming quite important as flavoring extracts. The peculiar flavors of fruits are probably due to the presence of these same esters in the substance of the fruits. Amyl acetate, 05H^^02H302, has the flavor of bananas; ethyl butyrate, O2H5C4 H7O2, of pineapples, and amyl valerate, OgH^j O5H9O2, is known as '' apple oil." We may here state, as a matter of some interest, that when or- ganic esters are treated with caustic alkalies the acid radical unites with the alkali metal, and the

Ethyl Alcohol, etc. 281

typical alcohol of the hydrocorbon radical is

formed. For example :

C.HuC^HjO^ + NaOH = NaC2H30, +

Amyl Acetate. Sodium Acetate.

C5H11OH

Amyl Alcohol.

Acetic acid acted upon in different proportions, by chlorine, yields three well-defined chloracetic acids, by giving up hydrogen. It is not, however, the hydrogen of the group COOH in the acid, which is replaced by chlorine, as is the case when acted upon by metals.

Acetic acid, CgH^Og

Monochloracetic acid, C2H3CIO2 ])ichloracetic acid, C2H2CI2O2

Trichloracetic acid, C2HCI3O2

The aldehyde of trichloracetic acid is the liquid chloral, C2HCI3O, a substance which, united with water, forms the familiar chloral hydrate.

Chloral is prepared by prolonged action of chlor- ine gas on pure ethyl alcohol.

CgllgO + 8C1 = 5HC1 + C2HCI3O

It is a thin, colorless, oily liquid, of little taste, but pungent odor; its sp. gr. is 1.502, it boils at 94^ (201F), and is freely soluble in water, alcohol, and ether. Solutions of caustic alkalies decompose it into formate and chloroform.

C2lI(M30 + KOII = KCIIO2 -H CIICI3

Chloral. Pot. Formate. Chloroform.

24

282 Organic Chemistry.

Chloral forms with water in molecular propor- tions, chloral hydrate^ C2HCl30,H20, a solid crys- talline soluble substance of peculiar odor and sharp, unpleasant taste. It melts at 46° (114F), and boils at 97° (206F).

Materia Medica.— Locally applied, chloral hy- drate possesses sedative, anaesthetic and antiseptic properties, and is assuredly an excellent topical remedy as an ingredient of liniments for the relief of neuralgia and rheumatic pains. Powdered chloral (hydrate) pressed into the alveolar pockets, in pyorrhose, will serve the double capacity of anodyne and antiseptic. Applied in substance to slightly moistened sensitive dentine, it cuts off, partially, indirect communication with the pulp by extracting moisture from the tubuli ; and to the exposed pulp, either alone or combined with cam- phor, or with aconite tincture, it causes, probably by the same physical change, an immediate lessen- ing of pain. It is of service also in the cure of in- dolent ulcers in the mouth and other parts.

Taken internally, chloral acts as a sedative to the entire nervous system, and secondarily to the heart. As a hypnotic, it reduces the blood pressure on the brain, and thus induces sleep by imitating the nat- ural anatomical phenomenon of that process, and by diminishing at the same time the conductivity

Ethyl Alcohol, etc. 283

of the sensory nerves. Awakening is not accom- panied by the digestive disturbances, nausea, and headache, which usually result from the use of opium.

In full doses chloral slows the heart's action and respiration, and lowers the temperature. It may cause death by either syncope, or coma, and those addicted to the chloral hahit often suffer with scor- butic sores and ulceration of the gums.

Dose: 0.30 - 1.25 Gm (gr. v - xx).

R. Chloral hydratis.

Pot. Bromide, aa 0.65 Gm (gr. x).

Syrupi aurantii cort.

Aq. menth pip. aa 15.00 f Gm (f.^ss). M. S, A hypnotic potion in acute alveolar abscess.

284 Organic Chemistry.

CHAPTER YIII.

ETHERS, ETC.

Oxygen Ethers are defined as alcohols (typical), with the hydroxyllic hydrogen replaced by an al- cohol radical. Thus :

Ethyl Alcohol. Ethyl Oxide.

They may nlso be regarded as bearing the same relation to the alcohols that metallic oxides bear to the metallic hydrates, and all belong to the water type.

ll\^ 1^2\^ Na|()

Hp H p Nap

Sodium Hydrate. Sodium Oxide. Ethyl Alcohol. Ethyl Oxide.

Ethyl Oxide (0.^115)20, comynon ether ^ known also as sulphuric ether, can be obtained from a large number oH ethyl compounds, as for instance :

c,Hj + c.nJo = Ki + %fAo

Ethyl Iodide. Pot. Ethylate. Ethyl Ether.

Ethers, etc. 285

Practically, ether is obtained from ethyl alcohol by the dihydrating influence of sulphuric acid, at the proper temperature : 2C,H,0 - 11,0 = C.Tli^O for, {C^ll,).0,]

Alcohol. Ether. I J

Ether is a clear mobile liquid of a strong, though not unpleasant odor, and a warm penetrating taste. Its specific gravity is 0.730. It is not readily solu- ble in water, and is not as good a general solvent as chloroform. Its boiling point is dangerously low, 35-5° (96F), and at still lower temperatures it evaporates rapidly ; the vapor is about two and a half times as heavy as air, and is highly inflam- mable. If ether be freely exposed to the air, it tends to oxidize into acetic acid.

Materia Medica. — Inasmuch as the rapid ab- straction of heat from a part reduces sensibility, the local employment of ether in the form of spray, on account of its volatility, has been favored to some extent in the operation of extracting teeth.

Ether internally administered in the form of Iloft'mann's anodyne, which is a compound of ether, alcohol, and ethereal oil, is antispasmodic, stimulant, and carminative ; in the preparation known as spirits of nitrous ether, composed of alcohol and ethyl-nitrite (02115^02), it is an excellent diuretic and diaphoretic, in fevers.

286 Organic Chemistry.

The first practical use of ether as a general anjBsthetic was made by Dr. Morton, a dentist of Boston, in 1846.

Althoug?i much slower in its immediate eifects, ether is considered a safer anaesthetic than chloro- form ; the stimulus to the heart is more pronounced, and continuous than with chloroform, albeit, ether should not be exhibited no more than other anaes- thetics wherever decided weakness of the heart, lungs, or brain, is seriously suspected.

In ether narcosis, the cerebrum seems to be the first of the nerve centers involved ; then the sensory, followed by the motor centers, of the cord ; and finally the sensory and motor functions of the me- dulla oblongata; thus, in the later stages inducing a slowing of both the heart's action and respiration. The time required for complete etherization, is from three to five minutes, and the quantity of ether, about 60.00 Gm (gij).

We may here place on record merely as a fact, and not in any degree as encouraging to dental quackery, the composition of so-called vitalized air. To one gallon of nitrous oxide gas, is added three drops of an equal mixture of alcohol and chloro- form.

Ethyl chloride, C2H5CI, on account of its ten- dency to induce excessive cold by rapid evaporation,

Ethers, dc. 287

lias been employed as a local aiuestlietic for sensitive dentine, etc.

Chlorine forms with the different series of homologous hydrocarbons, a new homologous series in each case; each member differing from the next, by CH2, and containing equivalent chlorine as a substitute for liydrogen.

CTI3CI CII2CI2

Methyl Chloride. Mithcne Chloride.

Ethyl Chloride. Etheuo Chloride.

C3H7CI C3HgCl2

Propyl Chloride. Propeae Chloride.

The density of these haloid ethers, increase in regular gradation, by each addition of CH2, just like the tj^pical saturated hydrocarbons. Indeed, we can almost realize in every instance, the physical properties of organic compounds, by observing their molecular weights, as to whether they are gaseous, liquid, or solid, and in every instance the vapor density of the substance, compared with hydrogen, is ascertained by dividing its molecular weight by 2.

Thus methyl chloride, CII3CI, is a gas 25 times as heavy as hydrogen, a little more than one and a half times as heavy as air. Ethyl chloride, C^lTsCl, is a light liquid, the vapor of which is two and a half times as heavy as air; and ethyl bromide, CgllsBr, is a liquid almost twice as heavy as water, although

288 Organic Chemistry.

it boils at a lower temperature, 72 (163F.) Its vapor density is nearly four times that of the at- mosphere.

Mixed oxygen ethers contain two different alcohol radicals, united to hydroxylic oxygen. They are produced by various reactions, as for example :

^^4 o + C,H J = KI + CH, I 0

-^ J Ethyl Iodide. P FT J

Pot. Ethylate. ^2'^^5

Methyl-ethy] Ether.

Methyl-ethyl ether,^^ | O Boils at 11°C Ethyl-butyl " ^2^5 Iq u 3Q0

Methyl-amyl " ^^| |o " 92°

Ethyl-amyl " ^2^5 |q u 112°

The other alcohols of the methane series, aside from those already alluded to (methyl and ethyl alcohols), and amyl alcohol, are interesting to us only as chemical curiosities.

Butyl and propyl alcohols, and those following, are susceptible of isomeric modifications. Cetyl alcohol^ CjgHggOII, is characteristic of spermaceta ; and rnelyl alcohol, CgoHg^^OH, is a necessary con- stituent of beeswax. These alcohols are solid.

Spermaceta and beeswax are really compound ethers, or esters, formed by alcohol radicals, united respectively to palmitic and melissic acids.

Mhers, etc. 289

Amyl alcohol, pentyl alcohol, Cgll^^OH, is the chief constituent of fusel oil, and occurs as a residue, after distillation of ethyl alcohol, espe- cially from the starch of potatoes. When pure, amyl alcohol is a colorless liquid, of unpleasant burning odor and acrid taste. Its specific gravity at 0° is 0.825. It boils at 130 (266F), and freezes at — 20°. It changes by oxidation into valeric acid.

CHI Amyl acetate, p^tt^A > 0, as its name suggests,

is an amyl ester which, on account of its pear-like odor, is used in flavoring cheap confectionery.

Amyl nitrite, C5Hi^]S"02, is also a compound ether, obtained by action of nitric acid on amyl alcohol; is a yellow colored oily liquid, of sp. gr. 0.877, volatile, and inflammable; boils at 83 (182F), and emits a persistent diffusive odor of ripe pears. In materia medica this ether is known as amyl nitris, and is used as a stimulant to the heart, in case of ordinary syncope or exces- sive anaesthetic narcosis. The vapor from 2 or 3 drops, inhaled from a napkin, produces immediate flushing in the face, dilatation of the arterial system and rapid pulsation and breathing. If pushed too far, the symptoms of carbon dioxide coma supervene. Its employment with ansemiac patients is safer than with those of plethoric habit. 25

^90 Organic Chemistry.

CHAPTER IX.

OLEFINES, ETC.

The homologous hydrocarbon series CnHgn, next isologous to the paratins, are simple multiples of CH2. They are dyad radicals, produced by ab- straction of two atoms of hydrogen from the satu- rated paraiius. Thus —

CH4 — H2 rzr CH2

Methane. Methene, or Methylene.

C2H6 — H2 = C2 H4

Ethane. Ethene, or Ethylene.

« - H, = CgHe

Propene, or Propylene.

« - H, = C.Hg

Tetrene, or Butylene. Penrene, or Amylene, etc.

These dyad hydrocarbon radicals are known as olefines, from the fact that the most important mem- ber of the series, ethene C2H4, forms with, chlorine, an oily liquid, CgH^Clg-

The first free members of the series, ethylene and propylene, are gases; butylene is an exceedingly volatile liquid, which boils at 3° (37F),and amylene also, which boils at 35° (95F) ; the higher members of the series, as melene, CgoHgQ, are solid.

OlejineSy etc. 291

The olefines maybe formed by various reactions, only one of which we will mention, i. e., the ab- straction of water, from corresponding monatoraic alcohols (methane series), by powerful dehydrating agents, such as sulphuric acid, zinc chloride, or phos- phoric oxide. Thus —

Amyl Alcohol. Araylene.

The alcohols of the olefine series are diatomic, as ethylene alcohol, C2H4 (0H)2. They are called glycols because the}' are intermediate in the series belonging to ordinary alcohol, and the series of tri- atomic alcohols, of which latter glycerine, C3H5 (OH) 3, is the best known.

Diatomic alcohols, glycols, produce by oxidation, two series of acids, monobasic an-d disbasic, re- spectively. The first is derived by replacing 2 atoms of hydrogen, in ethylene, for instance, by 1 atom of oxygen, and the second by replacement of all 4 atoms of hydrogen by 2 atoms of oxygen. CII2OH C2OH COOH

CII^OH COOH COOU

Ethylene Alcohol Glycollic Acid. Oxalic Acid.

The acids of the glycollic series having but one group of COOH are monobasic ; those of the oxalic series are dibasic. Accordingly we have the gly- collic, or lactic acid series:

29^ ' Organic Chemistry.

Carbonic acid, CHoOg Glycollic acid, C2H4O3 Lactic acid, CgHgOg Butylactic acid, C4Hg03 Valerolactic acid, Ogll^QO^

And the oxalic series:

Oxalic acid, C2H2O4

Malonic acid, C3H4O4

Succinic acid, 04Hg04

Pyrotartaric acid, CgHgO^, etc. Lactic acid is the characteristic acid of sour milk. It is formed also by lactic fermentation of glucose, and starch, and many other vegetable products by the influence of several bacteria, the special microbe penicillium glaucum being probably the most charac- teristic. The acid is now extensively prepared by supplying a pure culture of lactic ferment to glu- cose obtained from corn starch. It can also be obtained artificially, by direct oxidation of propy- leue glycol, C3H, (OH)^ + O^ = H,0 + CgHeO,, and by various other chemical processes. It is found in the stomach and small intestines ; the flesh of animals also contain an isomeric modification, called para-lactic acid. All the salts of lactic acid are soluble in water and alcohol, insoluble in ether. Lactic acid is a heavy liquid of specific gravity 1.215 ; it is highly hygroscopic and is soluble in water, alcohol, and ether. The formula :

Olefines, etc. 293

f OH \ j \COOH/^^^)

CH2— OH -^ COOH / (^ 6H2-COOH,

will enable us to understand the reactions that may occur between lactic acid, and positive radicals. With metals such as zinc, and calcium, it is only the hydrogen of the group COOH that gives its place to the metal; the metals of the alkalies however are capable of removing likewise, the hydroxylic hydrogen. In this connection the fol- lowing formulas are suggestive :

2(CH3-CH <coo)^^- ^^3-CH<^(^(^j^^

Calcium Lactate. Sodium Lactate.

Disodium Lactate.

Hydrocarbon radicals can displace either the alco- holic hydrogen, or the basic hydrogen, or both, in the lactic series of acids, and these acids therefore, can form three different ethers. As,

Ethyl Lactic Acid Monoethyl Lactate.

CH3-CH<g5%H»j^^

Diethyl Lactiite.

The principal exciting cause of caries of the teeth, has been generally accepted, since the published experiments of Prof. W. D. Miller, as due to lactic fermentation in the mouth. Food carbohydrates, amylaceous, and saccharine, are especially disposed to this form of fermentation,

294 Organic Chemistry,

starch. Glucose, Levulose, and Dextrose

CeHi,Oe=2C3He03.

Glucose. Lactic Acin.

Ci2H.,Oi,+H,0-4C3He03.

Grape or Milk Sugar. Lactic Acid.

Free lactic acid destroys the bacteria that produce the fermentation ; but the acid as it developes in the cavity of decay, is at once neutralized at the expense of the mineral portion of the tooth struc- ture, calcium lactate, CaCCsH^Og),, being formed, which permits a continuation of the process.

Oxalic Acid, C2H2O4, is the characteristic acid of wood sorrel and rhubarb. When evaporated from solution, it occurs in prismatic crystals, resembling magnesium sulphate, but very poisonous. It may be produced artificially, by oxidizing starch or sugar, with nitric acid, and is now largely manu- factured from sawdust.

Oxalic is the first of a long homologous series of acids ; the immediate succeeding members are given on page 292. They are all dibasic, and can there- fore form both normal and hydrogen salts. Of these, succinic acid is the most interesting on ac- count of its relation to malic and tartaric acids. CII -COOH CHOH-COOIl CHOH-COOIl

I 1

iH,-COOH CH2-COOH CHOH-COOIl

succinic Aoid. Malic Acid. Tartaric Acid.

Olefines, etc. 295

Malic is the acid of apples, and certain other fruits and vegetables, it occurs in white soluble crystals.

Tartaric acid exists in the juice of grapes, tama- rind, etc. During the fermentation of wine, potas- sium tartrate is deposited on the sides of the wine casks ; hence the name tartar, is given to deposits on the teeth.

Tartaric acid occurs as a white crystalline sub- stance, of very sour taste. It forms the contents of one of the papers, in Seidlitz powder; the other paper containing a mixture of hydrosodium car- bonate and potassium sodium tartrate. On solution in water, effervescence, by the escape of CO 2, takes place.

Cream of tartar, is hydrogen-potassium tartrate,

TT 1

-j^ >C4H40g; the best varieties of baking-powders,

are mixtures of cream of tartar, and hydrogen sodium carbonate (bicarbonate of soda).

The moisture of the dough, when heated induces the following reaction :

HNaC03+HKC4H406=KNaC4H40e4-H20+C02.

Rochelle Salt.

The escaping CO2, raises the dough, thus confer- ring lightness; the Rochelle salt remains with the bread.

296 Organic Chemistry.

Tartar emetic is tartrate of potassium and anti- mony, qi ^ VC^H^Og, used more or less in medi- cine, as an emetic.

Citric acid, CgHgO^, although not related to the above, is also a fruit acid, being found in the juice of oranges and lemons; and in other fruits, as gooseberry, currant, etc., in company with malic acid.

This acid is tribasic, as may be seen by the sub- joined condensed formulae :

Hj Hj

Citric Acid. Monopotassium.

Citrate.

Hj Kj

Dipotassiura. Tripotassium.

Citrate. Citrate.

Fatty AcidSy etc. 297

CHAPTER X.

FATTY ACIDS, ETC.

By reference to the table of corresponding alco- hols and acids on page 276, it will be seen that the solid acids, named pahiiitic, margaric and stearic belong to the group of monobasic /a^^y acids. Pal- mitic acid, Cigll3202, occurs as an ether of pro- penyl, in many natural fats, and in palm oil; also in cetin of spermaceti, and in melissin of beeswax. It is a solid, lighter than water ; it melts at 62° (144F), and when heated with alcohols, yields compound ethers. Margaric acid, C^rjU^^O^^is in- termediate between palmitic and stearic acids. The latter acid, CigHggO, occurs in the more solid fats of animals ; also in the softer fats, as butter and goose grease, and in some of the fats of vegetable origin, as in cocoa butter. Stearic acid is a solid, a little heavier than water; it melts at 69° (162F) and distils without alteration.

Oleic acid, C18II34O2, is monabasic, but belongs to another series of acids, having the general formula, CnH2n — 2^2- -^^ ^^ ^^^ fluid constituent of most natural fats and fixed oils; it solidifies at

298 Organic Chemistry.

4° (39F), and is, therefore, liquid at common

temperatures ; its specific gravity is 0.898. These

fatty acids are found in nature as ethers of the

radical propenyl, C^H^'^'.

Glycerine, Glycerol, is propenyl alcohol, and as

propenyl, is a triad radical, the alcohol in question

must be triatomic.

fOH

{ OH

(OH

With some monobasic acids, therefore, this alco- hol may form three distinct ethers, as with acetic acid :

CC,R,0, (C2H3O2 fC^HgO^

C3HJ0H C3hJc,H30, C3HJCHO

(-0H (OH (C,H30,

The natural oils and fats are generally found as

triple (normal) ethers of palmitic, margaric, stearic

and oleic acids :

CgH^'^'^OH

C3hJc,,h,,o, C3hJo,,h O

IC16H31O, lCi,H330

Palmitin. Margarine.

c3hJc,,h::o: c3hJc;h o

t-CisHjsO^ IC13H35O

Stearin. Olein.

When these fatty ethers are saponified by alka- lies, a salt of the alkali metal (soap) is formed, and propenyl alcohol thus set free.

Fatty Acids, etc. 299

C3H5 (Ci3H3502)3 + 3K0H = 3KCi«H3,02 + C3H, (0H)3 Propenyl Stearate. Pot. Stearate. Prepenyl Alcohol.

(Stearin). (Soap). (Glycerine).

Glycerine is also produced in small quantity in sugar fermentation, and is now separated largely from the fats, hy high pressure steam.

When acted on by dilute nitric acid, glycerine

exchanges 2 atoms of hydrogen for 0, forming

glyceric acid.

CH2OH

CHOH

I COOH

When treated with strong nitric and sulphuric acids, glycerine yields the explosive compound known as nitro- glycerine, C3H5 (^Ogjg. This pro- penyl-nitrate is a thick oily liquid ; it burns quietly, but if struck fiercely or ignited by a fulminate, it explodes witli frightful violence. It is the basis of different varieties of dynamite, which consists of absorbed nitro-glycerine in infusorial earth or saw- dust, etc., to a porous pasty solid, of less danger in handling than the liquid.

Glycerine itself is a syrupy liquitl of sp. gr. 127, is nearly colorless, and of sweetish taste. When pure, it is said to boil at the high temperature of 290° (554F), a fact which suggested its employment in an open dish for valcanizing rubber, to avoid the danger attending the ordinary method.

800 Organic Chemistry.

•

Commercial glycerine contains too much water to permit a sufficient elevation of temperature for the purpose, and even where the pure variety is used, acrid vapors consisting of acrolein^ C3H4O, are given oft*, the same as from the wick of an im- perfectly quenched candle.

Materia Medica. — Glycerine is soluble in water and alcohol ; insoluble in chloroform and ether. It is a good solvent for various drugs, such as tan- nin, creosote, carbolic acid, iodine, borax, quinine, etc. It is antiseptic and soothing, and is applied as an emollient to sore or inflamed surfaces, either alone or as a vehicle adjunct for other remedies, as in the following Glycerita:

Glycerina, . 30.00 fGm. (fgi) Acidi Tannici, 8.00 Gm. (^ij)

Glycerina, . 30.00 fGm. (fgi) Acidi Carbolici, 8.00 fGm. (f^ij)

Glycerina, . 30.00 fGm. (f^i) Sodii Biboras, . 8.00 Gm. (gij)

The univalent radical allyl, CI3H5, is isomeric with the trivalent radical of glycerine, propenyl. They differ in structure, however, as the following formulas will show :

	Fatty	Acids,	etc.
H 1
H L H-C-	-OH -OH			H C H C H H C OH H Allyl Alcohol.
H C H Glycerol.	-OH

301

The natural oil of garlic owes its pungency to allyl sulphide (C3H5)2S ; the oil of mustard, to allyl sulphocyanate, C3H5CNS.

302 Organic Chemistry.

CHAPTER XL

AMYLENE, ETC.

We have alluded to the olefines, dyad hydrocar- bons of the general formula, CnH2n, and stated that one source of their derivation is by dehydrat- ing the alcohol of the same number of carbon atoms. Thus, isopentene (amylene), CgHj^, is ob- tained by action of dehydrating agents, such as sulphuric acid, zinc chloride, phosphoric oxide, etc., on pentyl (amyl) alcohol,

C,HiiOH-H,0 = C,Hi„.

The formula, CgHj^, is capable of four modifi- cations. Normal pentene, sometimes regarded as ethyl-allyl, C2H5,C3H5, is obtained by action of sodium on mixed ethyl and allyl iodides. The third possible modification is not well known, while the fourth variation, is probably identical with the new anaesthetic called pental.

These possible variations of C^H^q are repre- sented below :

Amylene, etc. 303

1st. CH3 — CH, — CH2 — CH = CH2

Normal Pentene.

2d. QH^>CH — CIL= CH2

Isopentene.

3d. CH3 — CH2 — CH = CH — CH3. 4th. qh'>C == CH — CH3

Pental.

Pental is said to be produced from amylene hy- drate (amjlene alcohol), by heating in the presence of acids. This hydrate is isomeric with amyl alco- hol. They differ, however, in certain properties, and therefore must differ in structure.

C^HjiOH C5H1JOH

Amyl Alcohol. Amylene Hydrate,

If these two alcohols be acted on by the same dehydrating agent, the resulting compounds would differ in some of their properties. They must, however, have the same vapor density. The boil- ing points of normal pentene, isopentene (amylene), and pental, approximate 35°-38° (95-104F), and probably vary in this respect, only on account of difference in absolute purity. Their specific grav- ities also approximate 0.663-0.6783. They are in- soluble in water, but mix freely in ether, chloro- form, and alcohol. They are exceedingly volatile and inflammable, and their vapor, when inhaled, causes insensibility to pain.

304 Organic Chemistry.

Amylene was introduced as an ansesthetic in 1856, but made slight impression. Pental was intro- duced to the profession in this country in 1891. Its odor somewhat resembles that of mustard oil, suggesting the radical allyl.

The claims made for pental as an anaesthetic in. dental operations, are :

To reach narcosis, requires but from 1-3 minutes.

Heart's action and respiration are not materially interfered with.

There is no spasm of the muscles.

The narcosis is brief, and the patient recovers without any accompanying headache, nausea or vomitings l^evertheless, pental has not been re- ceived thus far with as much favor as its friends think it deserves.

The series of hydrocarbons, CnH2n — 2, of which Ethine (acetylene), C2H2, is the only important member, belong to the fatty compounds, like the paraffins and alefines, as distinguished from the aromatic compounds. The first two numbers are gases, the others increasing in density through liquid and solid states, by each additional CH2.

Acetylene, C2H2, is a constituent of coal gas, on which it confers, largely, a disagreeable odor. It may be produced by various decompositions of organic compounds, but it is especially distin-

Amyhne, etc, 305

giiished ag the only compound, formed synthetically by direct union of carbon and hydrogen.

When a strong electric arc current is passed from carbon poles through an atmosphere of hy- drogen, the carbon, as it volatilizes, unites with the hydrogen, 2H + 2C = C2H2.

From acetylene, a great number of organic com- pounds can be obtained. Thus, by aid of platinum black, it will take up 2 atoms of hydrogen to form ethylene, C^H^, C^H^ -f H2 = CJi^.

Ethylene combines with concentrated sulphuric acid to form basic ethyl-sulphate, 03114 + H2SO4 = H, C2H5SO4, and this, when heated with caustic potash, yields as follows : ^

H, C2H5SO4 + 2K0H = C2H6O + H2O + K2SO4

Alcohol,

In ethane, C2Hg, the 2 carbon atoms are united by 1 bond, in ethene (ethylene (C2H4), the carbon atoms are united by 2 bonds, and in ethine (acetylene) the carbon atoms are united by 3 bonds, thus : H

H— C— H

H— C— H H— C-H C— H

I II III

H H— C— li C— H

Ethane. Ethene. Ethine.

The hydrocarbons of the general formula, Cn 26

306 Organic Chemistry.

HgH — 6, are represented by the first member of the series, Benzene, C5gHg, (not the petroleum product, Benzine); the second member Toluene, C^Hg, is also frequently miscalled benzol and toluol. The other members of the group, are susceptible of isomeric modifications, and they all belong to the Aromatic series of hydrocarbons, so named because many derivatives of benzene, such as benzoic acid, oil of bitter almonds, etc., possesses a fragrant odor.

Benzene, C^Mq is chiefly obtained from the coal tar of the gas-works. It is a light highly inflam- mable liquid, which boils at 80° (176F.) and freezes at 3° (37F.) ; it is soluble in alcohol and ether, scarcely so in water, has an ethereal odor, and is produced largely, for the manufacture of aniline dyes.

The six carbon atoms in benzene, form a closed ring ; they are united by 1 and 2 bonds, alternately, permitting one bond, belonging to each atom to remain free, forming thus a quasi hat-rack, which is capable of receiving alternately, innumerable ele- mentary or compound univalent radicals ; so the derivatives of benzene may be considered practically illimitable, and thousands of them are already known.

	Benzene, etc.	30
c c	H C C H // \ H C C H \ /	H C C CH \ / H C-=C H
Benzene Ring. (Hat-rack).	Benzene.	Methyl Benzene. (Toluene).

Groups of compound radicals like CHg attached to the nucleus ring, in the place of II, form lateral chains, which themselves may give up H, to form substitution derivatives.

The homologues of benzene, as toluene, etc., (CgIIg + CH2, etc.), may be derived by substitution of methyl, CHg, for one or more of the six hydro- gen atoms ; and where but one hydrogen atom is removed from benzene, the compound radical j)/ien?/^, C5II5, is presented.

Benzene itself, is the hexune of Hoffmann ; and its homologues are isologous with many hydrocarbons of great interest, and practical use, such as cinna- mene, Cgllg, naphthalene, C^QlIg, and anthracene, Cj4H^Q, and the terpenes, Cj^Hig.

PAen?/?rt^co/io^,CgH5 0H, commonly called carbolic acid, is usually obtained from coal tar by distilla- tion, between the temperatures of 150° and 200° (302-392F.) It is also produced by various other methods of reaction on benzene derivatives, and by dry distillation of organized complex substances, such as coal and wood.

308 Organic Chemistry.

This phenol shows its relation to benzene, by the graphic formula : H — C — C — H

H_C C— 0— II

\ / H— C=C— H. Although not

an acid, it takes its name as such, because it forms salts with the alkalies, such as potassium phenate OgHgOK, by giving up its hydroxylic hydrogen to the metal. This reaction however suggests an alcohol, and moreover, carbolic acid forms, like the alcohols, compound ethers, such as methyl phenate O^H^ — 0 — CHg, {anisol), and ethyl phe- nate CeH^r^O— C2H5, (phenetol), etc.

Materia Medica. — Phenyl alcohol, carbolic acid, phenic acid, simply phenol, w^hen pure, occurs in clear prismatic needles of specific gravity 1.066; it melts at 40° (104F), and boils at 181° (357F). It possesses a smoky odor and burning taste. It forms a complete aqueous solution with 95 per cent of water, and will liquefy by the presence of 5 per cent of water.

It acts as a local anaesthetic when applied to soft parts, as the dental pulp, probably by forming, with albuminoids, a protecting coagulum. It acts as a superficial caustic when applied undiluted, and is one of the best antiseptics, so long as the coagulum, which it forms with the substance of the

Benzene, etc. 309

tissue acted on, or with the substance of bacteria themselves, remains undissolved.

When dissolved in chloroform, ether, or alcohol, the caustic properties of carbolic acid are enhanced; it also dissolves in the essential oils and in glycerine, which somewhat diminish its causticity. It is an active poison.

Dose, 0.06 Gra. (grj) in solution, or pill.

Antidotes, olive oil and saccharated lime.

Bobinson's Remedy, composed of equal parts of carbolic acid and caustic potash, is useful in al- veolar pyorrhoea, and with arsenic, for destroying dental pulps.

Phenol Sodique is a solution in water of 5 parts carbolic acid and 1 part of caustic soda, useful as an ingredient of antiseptic mouth washes. Phe- nol trichloride is antiseptic and a powerful disin- fectant.

B. Acida carbolici, 2.00 Gin. (3ss) Glycerin!, . 10.00 fGm. (fsijss)

Aq. Rosaq. s. ad., 120.00 fGm. (f^iv) M. 8. Antiseptic solution. Creasote is a product of the distillation of wood tar, and is a mixture of several phenols, such as carbolic acid, creasol, C8H1QO2, and cre- sylol, C^IIgO. These latter may also be attached to the benzene hat-rack:

810 Organic Chemistry.

H-d C— OH H— C 6— OH

H— C-=C— OH H— C=C— H

Creasol. Cresylol.

Creasote is an oily liquid of specific gravity 1.08. It possesses a caustic burning taste, and a pene- trating empyreumatic odor. On long exposure to light, it turns to a reddish yellow. It mixes in all proportions with ether, alcohol, acetic acid, and naphtha, but not with glycerine. With water it forms two solutions, 1 part creasote to 80 of water, and 10 parts creasote to 1 of water. It may be distinguished from carbolic acid by producing a green instead of a brown color, with alcoholic so- lution of ferric chloride.

Creasote possesses many of the virtues of car- bolic acid. It is antiseptic, anaesthetic, escharotic, and styptic. When applied to exposed dental pulp, it effectually relieves the pain; and when di- luted, it is useful as an application to ulcerative conditions of the skin and mucous membrane. It is preferred to carbolic acid as an internal remedy in phthisis, nausea, cholera, and passive hem- orrhage.

Dose, 0.06-012 fGm. (ntj-ij) Antidotes, same as carbolic acid.

Benzene Group. 311

CHAPTER XII. BENZENE GROUP.

The aromatic alcohols of the henzene homologues, are formed by substitution of OH for H in the lat- eral chains, and contain the group CH^OH. As,

H_C— C— H H— C— C— H

H_C C— CH, H— C C— CH.OH

\ / ' \ /

H— C=.C— H H— Cr=C— H

Toluene. Benzyl Alcohol.

They are therefore primary alcohols. They change to aldehydes, and acids, by oxidation, and yield ethers, analogous to those of the monatomic alcohols.

Benzoic Acid, CgllgCOOlI, is characteristic of the urine of herbivorous animals. It exists already formed in certain balsams and gum resins, as in gum-benzoin f which exudes from the Styrax Benzoin tree of Borneo, and adjacent countries. It may also be obtained by various reactions on many benzene derivatives. It is an inodorous solid, but when warm, emits a faint agreeable odor; it melts at 120° (248F.) and boils at 250° (482F.) ; is freely soluble in alcohol but sparingly so in water. Its

812 Organic Chemistry.

salts called henzoates are generally soluble in water and have the formula, MC^HgOg.

Calcium benzoate is changed by dry distillation into calcium carbonate and benzone, or the ketone of benzoic acid.

Ca(C,H50,), =CaC03 + C.H^-CO-OgHj.

Benzoic acid is a good germicide and antiseptic, and is stimulant to mucous surfaces. It is proba- bly the most active ingredient of the antiseptic mixture known as Listerine, and is also one of the ingredients of ^'Harris' Gum WasA." It is used internally in gout, calculi, inflammation of the bladder, and incontinence of urine. Dose, 0.50 Gm. (gr. vij.)

Benzoin tinctures, are effective in treatment of ulcerative inflammation of the oral mucous mem- brane, and of sloughing wounds.

Ammonium benzoate, ^}l^CrjlIfi2^^^ antacid and stimulant, and is acceptable to the stomach, in acid dyspepsia.

The new substance, saccharine, which is said to possess 300 times the sweetening power of cane sugar, is a derivative of benzoic acid. It is the anhydride of orthosulphamidobenzoic acid.

Benzaldehyde, is the familiar fragrant oil of bitter almonds.

Salicylic acid, QqW^^^^^^^jx occurs in salicin, of

Benzene Group. 313

the willow and poplar, and free, in the flowers of meadow-sweet; and as niythylic ether, in oil of wintergreen (Gaulheiia procinnhens)^ from which it may be obtained by distillation with potash. It is however principally prepared by heating sodium phenate with carbon dioxide.

Salicylic acid appears as a white crystalline powder, freely soluble in glycerine, alcohol, and ether, sparingly soluble in water; is without odor, or taste, but leaves a sweet astringent aftertaste; it is resolved, by heating with pounded glass, into carbon dioxide, and phenol. It is an excellent anti- septic, and is somewhat disinfectant, and is fre- quently employed with good results, in powder or ethereal solution, as a dressing in suppurating root canal ; and in alcoholic solution with borax, in treatment of aphthae, and other inflammatory con- ditions of the mouth. Mild alkalies, as borax and Hodii phosphas, increase its solubility. It is afi:ec- tive as a deodorizing dentifrice, when combined in proper proportion with suitable vehicles; when in strong solution, its acid nature is objectionable to the teeth.

Dose, 0.50-1.25 Gm. (gr. viij-xx.)

Gallic Acid, dioxysalicylic acid, trioxybenzoic

acid, CyHgOg, may be also erected on the benzene

ring.

27

Si 4 Organic Chemistry.

H-C— C— OH

H— C C— OH

\ / HO— C=C— COOH

Gallic acid is a constituent of nut galls, and many other vegetable bodies, but is most conven- iently prepared from tannin. It is acid in reaction^ is only slightly soluble in cold water, but freely solu- ble in hot water, and in alcohol, ether, and glycerine. It possesses astringent and styptic properties.

Dose, 0.10-0.30 Gm. (gr.ij-v.)

Tannin, tannic acid, gallotannic acid, C,,R,,0, == 0 C,11,={0R),

CO-CeH^^COH)^

COOH Ordinary tannic acid is obtained from nut galls, which are produced as an excrescence on the young twigs of the species of oak known as the quercus infectoria, by the puncture of the insect cynips gallce iinctorice. The galls are irregularly rounded and tuberculated nuts, from J to } of an inch in diame- ter, of a green gray color, and of decidedly astrin- gent taste. The favorite galls, come chiefly from the Levant. They are rich in tannic, and gallic acids.

Medicinal tannin, is obtained from powdered galls by the action of commercial ether. It is a feathery

Benzene Group, 315

amorphous powder, of a light yellow color, soluble iu water, glycerine, alcohol, and ether. It produces coagula with gelatine and albumen, smd precipitates with vegetable alkaloids, and with ferric com- pounds. These substances are therefore incompat- ible with tannin.

Materia Medica. Locally applied tannic acid is especially astringent. It is therefore suggested as a good local application in inflammations of the mucous membrane, in either one of the extreme portions of the prima via. In passive hemorrhage, sometimes excessive, after the extraction of teeth, pledgets of cotton wool, holding tannin en masse, inserted into the bleeding sockets of the alveoli, will nearly always eifectually arrest the hemorrhage, by its astringent action on the vessels, and by its coag- ulating effect on the albumen of the*escaping blood.

Internal 1}% tannin combinations, are frequently exhibited in diarrhoea, cholera, and hemorrhage.

Dose 0.06-0.18 Gm. (gr.j-iij.)

R. Acidi Tannic! 4.00 Gm. (.^i). Glycerins). Aqua Dest. aa 15.00 fGm (fgss).

M. S. Apply in nursing sore mouth.

The tannins are the active astringent principles of various vegetable bodies, such as krameria, catechu, kino, hsematoxylon, hamamelis, or witch-

316 Organic Chemistry.

hazel, and of quercus alba, and other species of oak. They are denominated glucosides because like amygdalin, coniferin, salicin, etc., they change by the action of ferments, or by dilute acids, or alkalies, into glucose (dextro) and other bodies, which are mainly derivatives of benzene.

Tannin may be regarded as gallic anhydride.

Tannin. Gallic Acid.

Nitro-benzene, C6H5NO2, is a volatile liquid, used in making cheap perfumery and flavoring essences.

When nitrobenzene is acted on by nascent hy- drogen it is changed to j)henylamine, C^H^l^YL^', also known as amidobenzene, or aniline.

C6H,K02+6H = 2H204-CeH5NH2. '

Nitrobenzine. Aniline.

Aniline is a liquid, slightly heavier than water. It possesses a smooth disagreeable odor ; is strongly basic and unites with acids to form salts. It istho basis of aniline dyes. And thus from the benzene of coal tar, erstwhile a waste product in the manu- facture of illuminating gas, comes those splendid colors, which confer on fabrics of silk, etc., the elegant shadings now so noticeable.

Trinitrophenol,CQH^ OH^ ^' ^^ ^^^^ known as

picric acid. The picrates are highly explosive salts.

Many derivatives of benzene are used in medi-

Benzene Group. 817

cine, such as salol, a compound of salicylic acid and phenol; phenacetine, and the analogous com- pound, acetanilide, Cgll^ — NH — C2H3O2 ; resor- cin, Cg 114(011)2 ; pyridine, CgH^^; naphthaline,

I I

H— C C C— H

I II I

H— C C /C-H

c c

k k

formulated by over lapping of two benzine rings; quinicine, C9H9N2, to which antipyrine, CiiHi2^2^? i^ ^^" lated, etc.

They are antiseptic, antipyretic, and analgesic ; and alone, or in various combinations with each other, or with other drugs, they are effective in performing the functions assigned.

Their dosage ranges from 0.25 Gm. to 1.00 Gm. (gr. iv-xvi), and their probable action consists of destructive deoxidation of protoplasm.

318 , Organic Chemistry.

CHAPTER XIII.

CARBO-HYDRATES.

Carbo-hydrates, so-called, because their molecules represent H and 0 in the proportion to form water, united to carbon. They include starchy woody fiber ^ and sugars.

Starch, CgH^oOg, is an important constituent of the vegetable kingdom, especially in grains, such as corn, wheat, and rice, and in potatoes. It is probably formed in the plant, somewhat according to the following equation :

6CO2 + 5H,0 = CeHioO^ + O^,

Starch consists physically of minute granules, insoluble in water, but which, when heated with water to 71° (160F), burst open and form starch paste. When heated to 205° (400F) starch is changed to isomeric dextrin^ a soluble substance used on the sticky surface of postage stamps. The same isomeric change is produced on starch by cer- tain dilute acids. Dilute sulphuric acid turns starch to dextrin, then to glucose. Saliva also pro- duces a similar change, as does the ferment on the

Carbo- Hydrates. 319

farinaceous mixture in the first stages of alcoholic fermentation.

The natural gums contain polymers of starch. Gum-arabic is a combination of potassium and calcium, with arabic acid -{CqYL^qO^)^. Agar- agar, or Ceylon moss, used for thickening soups and jellies, and in cultures for growing microbes; and other vegetables, as beets and carrots, as well as many fruits, contain polymers of starch and dextrin. Animal starch, glycogen^ is found in the liver and placenta.

Solutions of starch and iodine, when mixed, turn to blue, by which the presence of starch, as dis- tinguished from its isomers, may be determined.

Cellulose, CgHjoOg, is the chief constituent of vegetable liber. Bleached cotton is practically pure cellulose, as is also linen that has been frequently laundried, a process which removes the inherent gums and resins from the surface.

When cellulose is treated with nitric and sul- phuric acids, NiTRO-CELLULOSE, or guncotton, also known as pyroxylin, Cgll^ (1^02)305, is produced. Guncotton is highly explosive.

Celluloid consists of pyroxylin mixed with cam- l)hor, zinc oxide, and coloring matters, and sub- jected to pressure while in the pulpy state.

320 Organic Chemistry.

Collodion is obtained by dissolving guncotton in a mixture of alcohol and ether. When the liquid collodion evaporates, it leaves a coherent iilm, known in surgery as a sort of artificial skin. Can- tharidal collodion, is used with some advantage as a counter-irritant in periodontitis.

The sugars are divided into two groups, sucroses, and glucoses.

SucROSES have the formula, Ci2ll2 2^ii? ^^^^ ^'^" elude cane and beet sugar (sucrose), milk sugar (lactose), and a variety of starch sugar (mal- tose), etc.

Glucoses, CgH^2^6? include grape sugar (dex- trose), SLiid fruit sugar (levulose), etc.

Cane sugar (Sucrose), is obtained from the sugar cane, sugar beet, sorghum, and sugar maple. It is a most important article of human diet. When refined, cane sagar, presents a white crystalline form, perfectly soluble in water. When heated it loses part of its aqueous elem.ents, and is converted into caramel.

Grape sugar (Glucose) exists in many sweet fruits, and m honey ; it occurs also as a concomi- tant in the disease known as diabetes.

Glucose IS largely produced artificially, by action of dilute sulphuric acid upon corn starch. It is

Carbo- Hydrates. 321

used extensively as a substitute for cane sugar, being cheaper, in the making of syrups, and candies; and on account of its ability to ferment, in the produc- tion of beer and ale.

322 Organic Chemistry.

CHAPTER XIV.

TERPENES, ETC.

The Terpenes, C^ oHj g, are homologous v^iihjpen- tone, CgHg, having the general formula CnH2n — 4 ; and areisologous with decane, CjqH22- They exist in the volatile or essential oils of certain trees and plants, especially of the coniferous and aurantia- ceous orders. They have not as yet been produced artificially, although some of them are structurally related to benzene.

Their formula is isomeric with decone, C^oH^g, and are regarded as tetrad radicals ; although ap- parently satisfied, they are capable of taking up two molecules of HCl. If the molecule, C^oHjg, be doubled, the polymer, C20H32, as in the case of

2 atoms of carbon, — C — C — , loses 2 units of

I I

valency, and becomes a hexad.

Cologne is an alcoholic solution of certain essen- tial oils.

Turpentine Oil, Oleum Terebinthince, C^oH^g, is the most familiar representative of the terpenes. It is obtained by distilling the juices which exude

Terpenes, etc. 323

from cuts in the bodies of several species of the genus jpine. The commercial variety contains some admixture of other hydrocarbons, and traces of oxidation products.

Rosin which remains in the retort, consists essen- tially of silvic acid, Cj9H2 9COOH.

Other resins, such as shellac, copal, sandarac, etc., are rosins, obtained similarly from various terpenes by distillation, or as the exudate from various kinds of trees.

The terpenes are disposed to absorb oxygen from the air, and thus pass into camphors.

That many volatile oils isomeric with oil of tur- pentine, such as oil of neroli, bergamot, cloves, pepper, caraway, lemon, etc., should exhibit such diversity of physical properties, is a problem which stereo-chemistry will doubtless be able to explain satisfactorily, in t4ie near future.

The antiseptic, and disinfectant, properties of the terpenes (essential oils) are in all probability due to their power of taking up oxygen from the air, by which two atoms of hydrogen are removed, resulting in CioHj404, a highly oxidized hydro- carbon, which with moisture, and summer-heat, developes nascent oxygen.

C,„II,,0,+2H,0 = H,0,+CioH,,0,.

Oxygenated Hydrogen Camphoric

Terpene. Dioxide. Acid.

324 Organic Chemistry.

Materia Medica. — Although many of the essen- tial oils (especially that of cloves), have been, from time immemorial, favorite domestic remedies afi^ainst toothache; and in practice, as ingredients of pulp capphigs, their introduction as disinfectant, and antiseptic dressings, in root canals, is mainly due to Drs. Harlan, Black and Barrett.

Oil of Cloves, oleum caryophilli, is obtained by distilling the dried buds (cloves) of an evergreen tree of the myrtle order, Eugenia caryophillata. The oil consists of caryophillin, CjoH^g, and an oxygen oil, eugenol, or eugenic acid, CgH^jCOOH. When fresh it is colorless, but by exposure, becomes yel- low, and finally, reddish-brown. It possesses a strong fragrant odor, and a hot aromatic taste; is nearly insoluble in water, but freely soluble in alco- hol. When mixed in small proportion with either carbolic acid, or creasote, it eflectually masks their peculiar odors. If applied to irritable dental pulp, in odontalgia, it reduces sensibility by its power of extra stimulation, and as a dressing in root ca- nals, by its diffusion through the tubuli, and its ultimate reduction to a camphor, prevents a return of the process of putrefaction in the part and the consequent pathological sequelae.

It is frequently exhibited internally as an anti-

Terpenes, etc, 325

spasmodic stimulant, in flatulent colic, nausea, and vomiting.

Dose, 0.12-0.30 fGm. (nt ij-v)

Oil of Sassafras is obtained oy distilling the bark and wood of the root of the sassafras offici- nallis, a native tree, of the genus laurel. The oil has a pleasant odor, a warm pungent aromatic taste ; oxidized by cold nitric acid, it is converted into a red resin. It is an excellent germicide, and is one of the ingredients of "sarsaparilla" syrup. The aqueous infusion of sassafras root bark is a popular "tea" and "blood purifier." Sassafras possesses mild astringent, stimulant alterative and diapho- retic properties. The powdered root, mixed with " chewing gum," and used as a masticatory, is a good adjunct in the treatment of alveolar py- orrhoea.

Dose of the oil, 0.06-0.25 fGm. (n^ j-iv)

Oil of Cinnamon, oleum cinnimomi, is obtained from the inner bark of the shoots of the cinnimo- mum zeylanicum (cassia), trees of the natural order Lauracese, growing In China, Ceylon, and adjacent countries. The Ceylon variety is the most es- teemed.

The oil is somewhat heavier than water ; of an agreeable odor, and a very hot penetrating taste. It is a powerful local stimulant, and when applied

326 Organic Chemistry.

to an aching dental pulp, relieves the pain. It is also a diffusive disinfectant and antiseptic, and is employed as such, preparatory to filling root ca- nals. On exposure, the oil of cassia tends to de- velop cinnamic acid (phenyl-acrylic acid, CfiHg - CH = CH - COOH). The properties of cinnamon, as a sialogogue, stimulant, astringent carminative, and uterine he- mostatic, when taken internally, is due to its con- tained oil and resin, and some tannic and cinna- mic acids.

Dose of the oil, 0.06-0.30 fGm. (j\ g-v)

Ter penes y etc. 327

CHAPTER XV.

TERPENES, ETC.— (Continued).

Oil of Wintergreen, oleum Gaultheria, from the leaves of the indigenous evergreen plant, Gaultheria procumbens, or Partridge-berry ; it exists also in the sweet birch, and other plants, and is largely composed of methyl salicylate CHgC^H^Og. It is the heaviest of the essential oils, and is largely used for flavor- ing; its principal use in dentistry is to disguise the disagreeable tastes and odors of other certain drugs, albeit it is itself an excellent antiseptic. It is em- ployed internally in rheumatic disorders, as a pleas- ant substitute for salicylic acid. A cold "• tea " of the leaves of the plant, is a popular astringent, carminative, and emmenagogue.

Dose of the oil 0.20-0.60 fGm. (ni iij-x.)

Oil of Eucalyptus, oleum Eucalypti, from the leaves of the matured Eucalyptus Globulus, or blue gum tree, a native of Australia, but now grown to some extent, in Italy, California, etc. The oil has a pleasant aromatic odor, a pungent somewhat cam-

328 Organic Chemistry.

phoraceous, cooling taste; it is composed of terpene, C10H16. cymene,

CioHi4=(C6H4<ci'-CH,-CH3)

and eucalyptol, CjqH^5(0H). It exhibits a destruc- tive influence on microbic forms of animal and vegetable life.

Alone or combined with other antiseptics, it is eftective in treatment of suppurating pulps, oral ulcerations, pyorrhoea, and chronic alveolar abscess. It is a solvent for gutta percha.

Internally administered, the preparations of eu- calyptus, act as a stimulent to the brain and nervous system; they increase the circulation, and respira- tion, and a re sialogogue, and diaphoretic; and tonic in gastric dyspepsia.

Dose of oil 0.30-2.00 fGm. (nv-xxx.)

Dose of tincture 2.00-8.00 fGm. (fSss-ij.)

B. Olei eucalypti.

Acidi carbolici aa 6.00 fGm. (f^jss.)

Olei Gaultheria 2.00 fGm. (f^ss.) M. S. Apply by syringe, in pyorrhoea (Dr. G. V. Black, from (jorgas.)

Oil of Caraway, oleum cari, is obtained from the fruit of a European plant, the Carum Carvi. Its odor is aromatic, and its taste acrid. It consists of

Ter penes, Phenols, etc. 329

the terpene, carvene O^QH^g, and the ten carbon phenol, carvol, C^oHjgOH.

Dose of the oil 0.06-0.30 fGm. ("I j-v.)

Carvacrol, CjQH^gOH, is isomeric, and probably- identical with carvol. It has a taste, persistent and strongly acrid, and a creasotic odor. It is a solvent for gutta percha. Is disinfectant and anti- septic ; and is analgesic, and escharotic on sensitive dentine.

Its principal source is oil of caraway.

Dose, not used internally.

Thymol, C ^ qH ^ 3(0H), is Isomeric with carvacrol. It is a constituent of the volatile oil of the garden plant, Thymus vulgaris, and of several other phmts. The isomeric relation of thymol, to carva- crol, may be most easily understood by the benzene hat-rack,

I I

H-C^ C— OH H— C^ C-H

H— C

n— H H— a £—011

Carvacrol. Thymol.

Both are methyl-propyl-phenols. In carvacrol the 28

330 Organic Chemistry.

methyl group (CHg) stands to the hydroxyl group (OH) in the or^Ao-position, and in thymol, in the 977 e^a- position.

Thymol crystallizes in transparant plates, of a mild pleasant odor, and peppery taste. It is prac- tically insoluble in water, but is freely soluble in alcohol, chloroform, and ether, and liquefies with camphor, and chloral alkalies. It forms, with glyc- erine, a good antiseptic.

Aristol, CioHi3(OI), is obtained from an alka- line solution of thymol, by adding potassium iodide solution of iodine, by which is produced a red-brown amorphous precipitate, consisting of thymol, minus its hydroxjdlic H, plus I, and may be chemically known as thymol lodroxide.

Aristol occurs in impalpable powder, almost tasteless and odorless. It is insoluble in water, glycerine, alcohol, and alkalies, but freely soluble in chloroform and ether, and is readily decomposed by light and heat.

Its insolubility in water enables it to act as an antiseptic, by preventing egress to the part, of septic germs ; and as a germicide, by the free iodine, which it slowly gives off, at the tempera- ture of the mouth.

Cotton wool, holding a saturated solution of

Terpenes, Phenols, etc. 331

aristol in chloroform, or ether, placed between teeth or over dressings in their cavities, will re- main comparatively odorless for indefinite periods of time.

Dose — Not used internally.

332 Organic Chemistry,

CHAPTER XYI.

TERPENES, PHENOLS, ETC.— (Continued.)

Resorcin, CgH4(OH)2, as may be presumed from its formula, is closely related to carbolic acid. It is a diatomic phenol, obtained by fusing caustic al- kalies with certain gums, as galbanum, or with po- tassium-benzol-disulphonate. By the latter pro- cess resorcin and potassium sulphite result.

Rosorcin occurs in prismatic shining crystals, of a sweetish pungent taste, freely soluble in water, less so in alcohol, ether, and glycerine, and not at all in chloroform. It is not so caustic and irri- tating as carbolic acid, although in strong solution it is fully as good an antiseptic. It is preferred to carbolic acid as an internal antiseptic and antipy- retic, being less poisonous. Dose, 0.30 Gm. (gr. v)

Oil of Peppermint, oleum menthce piperitm, ob- tained by distilling the fresh leaves of the plant. It consists of a terpene and a mon atomic alcohol, the latter called menthol, CiqHj9(0H); also known as peppermint camphor.

Terpenes, Phenols, etc. 338

Menthol, applied locally, is a non-corrosive vas- cular stimulant, antiseptic, and anaesthetic.

Pyrethrum, Pellitory ; the root furnishes an oil which, applied in ethereal solution, relieves adon- talgia. The flowers of Persian pellitory are used as " insect powder."

Oil of Orange Flowers, oleum neroli, is of de- lightfully fragrant odor.

Caoutchouc, India-rubber, is a thickened gum of the milky juice of several trees, as Euphorbia, growing in tropical countries. Para gum, shipped from Para, on the Amazon, is the most highly prized. Caoutchouc consists essentially of a mix- ture of terpenes, isomeric or polymeric, with oil of turpentine (C^oH'^g). It softens by heat; is not soluble in water or alcohol, but dissolves in chloro- form, pure ether, turpentine, benzene, and carbon disulphide. Mixed in variable proportions with sulphur, and heated, it becomes vulcanized India rubber. With one-half its weight of sulphur, ebonite is formed. Coloring matters are also often added, as Vermillion (Hg2S), to give it a red color; white clay and zinc oxide, to produce white rubber, etc.

Gutta-percha is the hardened juice of the iso- nandra percha tree, growing in Malacca and adjacent islands. It resembles caoutchouc in many re- spects, being insalubla. lu. w.atex,. aud capable of

334 Organic Chemistry.

vulcanizing with sulphur. It is less elastic than rubber, and is a very poor conductor of electricity, hence it is extensively used as an electric insulator. Gutta-percha, mixed with zinc, oxide, is used as a " filling " material, and retains its identity in the teeth against chemical action, but soon succumbs to active attrition.

IS'aphthaline, CjoHg, is a product of the distil- lation of coal-tar. It occurs in large white crys- tals of tarry odor and somewhat aromatic taste ; insoluble in water and in dilute acid and alkaline solutions, but soluble in chloroform, ether, volatile and fixed oils, benzene, and hot alcohol. It is a valuable antiseptic; combined with iodoform it forms an excellent dressing in root canals.

Hydronaphthol, C^qH^OH, derived from naph- thaline, crystallizes in shiny white scales, sparingly soluble in water, freely soluble in alcohol, glyc- erine, etc. It is non-poisonous, but is an excel- lent germicide and antiseptic in dental practice, and is also favorably exhibited as such, in general practice, especially in ailments of the intestinal canal.

HesinSy Camphors^ etc. 335

CHAPTER XVII.

RESINS, CAMPHORS, ETC.

Myrrh is a fair representative of gum resins. It is an exudate from the stems of the Balsomodendron myrrha, a small tree of South-western Asia and I^orthern Africa. When comparatively pure, it comes to us in semi-transparent yellow-reddish tears, held together in considerable bulk, of agree- able odor and aromatic bitter taste. It may be pulverized, and is soluble in ether and alcohol. It is a mild stimulant astriiigent to mucous surfaces, and is an effective application in the form of pow- der or tincture, to relaxed ulcerated conditions of the gums and throat.

Dose of the tincture, 2.00-4.00 fGm. (fess-i)

K. Aluminis, .... 4.00 Gm. (^i)

Tincture Myrrhse, . . 8.00 fGm. (f^ij) Infusi Rosse comp. . . 160.00 fGm. (f^v)

M. S. Use as a gargle.

(Modified from Farquharson.)

Camphor, C^oII^gO, common camphor, (like other camphors, such as caryophillin, 02 0113 2 0^), may be regarded as an okyK^v''?'t.c>d''^^rp'feii.f,\ Closely re-

• • • • • •

' • • • • • •

' • • • • • t

I • • • • • • •

• • • • • < •

336

Organic Chemistry.

lated to these, are many solid and liquid camphors which react as alcohols or stearoptenes, such as Borneol, or Borneo camphor, C^qH^-^OII, and its homologue, patchouli camphor, C^ 5 II 2 7 OH, menthol, or mint camphor, C ^ q II ^ 9 OH, absinthol, C ^^ q H ^ 5 OH, etc. Camphors are also obtained from the volatile oils of many plants, such as the oils of lavender, cajeput, orange, rosemary, coriander, hops, marjo- ram, etc., etc. By reaction with strong oxidizing agencies, such as nitric acid, ozone, etc., they are changed into acid com[)Ounds, of which camphoric acid, CgH^ 4(00011)2, is a fair representative.

The chemical relation between camphor, which is a ketone, and Borneol, which is a monatomic al- cohol, and camphoric acid, may be differentiated by erecting them in graphic formulae, thus :

CH,

CH

H— C^ C=C=.0 \ / 2 C-H	H-C^ C— 0-H
H^^C C=:H2
C-H
C3H, Camphor.	C3H7 Borneol.

c »

e «• t c <

I

liesinSj Camphors y etc. 337

3

PH 11— C' ^C— 0

,4

H2=C C— 0

C-II OH

C3H7

Camphoric Acid.

Common camphor is obtained in a crude way by distilling with water the, wood of the Laurus camphora tree of South-eastern Asia. It is a col- orless translucent solid, of sp. gr. 0.935 ; of a pen- etrating, aromatic odor, and rather unpleasant taste ; sparingly soluble in water, but freely soluble in volatile oils, strong acetic acid, ether and alco- hol. Pieces of camphor thrown on water, show the high volatility of the substance by the vapor pressure on the water, causing a rotatory motion of the granules; if they be covered with oil, which prevents evaporation of the camphor, rotation in water will not occur.

Camphor is an important ingredient of many liniments in common use. When locally applied, it exhibits irritant, rubefacient, and finally, ano- dyne properties. ComVjined with chloral, or in strong solution with chloroform, it is an effective local anaesthetic, and i^ lused ^s euch in obtunding

29

J J J >

338 Organic Chemistry.

sensitive dentine^ exposed dental nerce^ and in al- laying the pain which often follows the extraction of teeth.

Internally administered, camphor is strongly an- tispasmodic, diaphoretic and anaphrodisiac. In large dose it is narcotic and depressant, but in small doses it is mildly stimulant and diaphoretic. Dose, 0.06-0.60 Gm. (grj-x)

Chloral camphor is a liquid obtained by triturat- ing together equal weights of chloral hydrate and camphor. The mixture exhibits antiseptic and ob- tunding properties, and is a good solvent for many alkaloids.

Compho-phenic, as its name implies, is a combi- nation of camphor and carbolic acid. It is non- caustic and non-irritant, and is antiseptic and somewhat anaesthetic when applied to sensitive in- flamed surfaces.

R. Camphora —

Chloral hydratis, aa, 16.00 Gra. (giv) Etheris sulph. 30.00 fGm. (fgi)

M. S. For office use.

Capsicum, cayenne pepper, is the fruit of the plant capsicum fastigiatum. It possesses a peculiar odor and very hot taste, and contains capsicin, the active principle and a volatile alkaloid.

Resins, Camphors, etc. 389

Capsicum is one of the most familiar of local irritants. They produce on the part, a vascular ex- citement which oftentimes modifies the pain of coming inflammation. Hence capsicum, as well as the fruit of the piper nigrum (black pepper), etc., are severally, and combined, employed in plaster form to prevent the painful development of ex- pectant periodontitis, subsequent to the operation of tilling root canals.

HuMULUS, Hops, the fruit cones, (strobiles,) of the common hop-vine, (humulus lupulus). The glandu- lar portion of the strobiles consist of irregularly rounded small grains, of a yellow color, known as lupulin, which contains also, in most abundance, waxy resins and tannin, and a volatile oil, consist- ing of trimethylamine (valerol, and lupulinic acid.

Hops are mildly hypnotic, tonic, and somewhat astringent. They increase cutaneous circulation, when externally applied, followed by a soothing influence on sensory nerves. A calming efl'ect is produced on localized inflammation, such as acute alveolar abscess, by a warm hop poultice, external to the part.

Dose of Lupulin, 0.30-0.90 Gni. (gr. v-xv.)

Calendula, the fresh flowering garden marigold, furnishes a tincture which possesses a stmiulant

S40 Organic Chemistry.

resolvent power, and which when applied to ex- posed pulp, or in alveolar sockets, after extraction of teeth, impresses itself favorably, by relieving in a large measure, the consequent pain.

>--.yl

Alkaloids. 341

CHAPTER XVIII. NATURAL ALKALOIDS.

Alkaloids are organic bases capable of uniting with acids to form salts. Many of them exist in union with characteristic acids, in certain vegetable products ; they also occur in animal bodies, as leucomaines ; and as a result of putrefaction, as ptomaines. They are mostly poisons, are closely related to the artificial amines^ and contain !N^ as an essential element.

Those that are made up of C, H, and I^, as nicotine, CjqHj4]N'2, etc., are generally volatile liquids; while those which also contain 0, as Caffeine, CgH ^^fi^^ Morphine, C^^H^glN'Oj, etc., are non-volatile solids.

^h.Q\r graphic formulas are not as yet determined. When uniting with acids to form salts, they behave like ammonia; the hydrogen of the acid is not set free, thus differing in interaction with acids, from the general effect produced by metals.

(NH3), + H2SO4 = (NH,).,SO,.

Ammonia. Am. Sulphate.

C,,HigN03 + H2SO4 = C,,1I^3N03H2S04.

Morphia. Morph. Sulphate.

Zn + H2SO4 = ZnS04 + II,.

Zn Sulphate.

342 Organic Chemistry.

Their names terminate in either ine or ia accord- ing to preference. As a rule, they are less soluble in water, than are their salts.

Quinine, quinia, 02 0112 4^2 02,3112 0, is the most highly prized active principle of Cinchona bark.

The genus cinchona comprise many species. They were named in honor of the Countess of Cinchon who was cured of a relapsing fever by infusions of the bark, sent her by the Jesuit Mis- sionaries in Peru.

Cinchona trees flourish mainly on the eastern slope of the Andes, between the 20th degree S. latitude, and the 10th degree N. latitude. They are now profitably cultivated in India, and in southern Asiatic islands.

Three varieties of cinchona bark are sufficient representatives of the entire genus.

1. C. Calisaya, C. Flava, yellow bark.

2. 0. SucciRUBA, red bark.

3. C. Pallida, pale bark.

Different cinchona barks contain variable quan- tities of numerous active medicinal alkaloids, of which quinia and cinchona are the most valuable. They exist in the bark, in union with kinic or quinic^ (monobasic pentatomic) acid, CgH7(OH)4COOH.

Quinine is separated from the bark, and the kinic acid, by dilute hydrochloric acid, which forms the

Alkaloids. 343

soluble quinia hydrochloride. By the addition of lime, calcium chloride is formed, taking thus from the quinia, the hydrochloric acid, and compelling the alkaloid to precipitate. This precipitate is washed in water, and taken up by boiling alcohol, which is afterward set free by distillation.

Quinine occurs as a white amorphous crystalline powder, inodorous, but of an exceedingly bitter taste; very sparingly soluble in water; freely sol- uble in hot alcohol, chloroform, ether, and the fixed and essential oils ; is alkaline in reaction and forms salts with acids, of which the sulphate is the most generally employed, and which has appropri- ated the name, quinine.

Quinia sulphate, (0201^24^2^2)2) HgSO^jSHgO, quinine, is rarely used locally.

In small doses, internally administered, it acts as a tonic, an antiseptic, and antiperiodic. In full doses it causes anemia of the brain, accompanied by ringing in the ears (cinchonism), partial deaf- ness and blindness, and frontal headache.

It reduces the reflex irritability of the spinal chord. At first it increases, and afterward slows the heart's action. It increases the number of white corpuscles, but prevents their amoeboid move- ments, and prevents, also, the due giving up of 0 to the tissues. For this latter influence, quinine

344 Organic Chemistry.

might be suggested internally in localized inflam- mation, such as acute alveolar abcess. It has but slight effect on the temperature of the body in full health ; but in fevers^ the temperature is dimin- ished by quinine.

Dose, 0.12-1.25 Gm. (grij-xx)

B Quinia sulphalis, 1.00 Gin. (grxv)

Ft. capsules, No. 5. S. Take one every two (2) hours.

(In either acute alveolar abcess or periodic supra- orbital neuralgia.)

Artificial substitutes for quinine are being rap- idly introduced by manufacturers. They are gen- erally of coal-tar origin, and belong to the ben- zene series, either directly, or as substitution pro- ducts. Some of them have been alluded to on page 316. They also possess active analgesic, germ- icidal and antiseptic properties. Of these com- pounds, Pyoktanine, methyl violet, is the one most used in dentistry, as an antiseptic dressing in root canals, but is objectionable as such, on account of its coloring influence on dentine. It is a violet blue powder, odorless, non-poisonous, sparingly soluble in water and alcohol, insoluble in ether, and very diffusible in animal fluids.

Alkaloids. 345

CHAPTER XIX.

ALKALOIDS— (Continued).

Morphine, Morphia, Ci^H^gl^Og, is the principal individual of the many active alkaloids found in opium.

Opium is the inspissated juice of the unripe cap- sules of the papaver. somniferum, or white (or black) poppy, indigenous to Asia Minor, and cultivated extensively in other countries. The poppy is an annual plant, growing from 2 to 3 feet high. The milky juice obtained from incisions in the capsules (poppy heads), becomes concrete by exposure to the air, and comes to us, in irregularly rounded or flattened cakes, of a brown color, strong narcotic odor, and bitter taste, exciting to salivation. It yields its numerous virtues to water, and alcohol, and dilute acids, but not to ether.

Morphine exists in opium in union withmeconic acid, CgllgOgCOOH. The favorite salt of mor- phine, is the sulp hate y (C^ 71119^03)2, H2SO45H2O, soluble in water and alcohol, but not in chloroform or ether. Consists of w4iite flocculent crystals, of bitter taste; is less astringent and diaphoretic than opium, but possesses greater power as a hypnotic

346 Organic Chemistry.

and anodyne. Morphine is not regarded with much favor as a local anodyne; but if it be injected in solution hypodermatically, or taken by way of the primce vice, it exhibits the most distinguished nar- cotic properties. At first, the brain is gently ex- cited, as with opium, followed by a soothing seda- tive eflect ; and sleep ensues, induced by cerebral anemia. Awakening is accompanied by headache, digestive disturbance, and (with opiura)constipation. Subcutaneous injection of. Morphia 0.01 Gm. (gr.f ) Aqua Dest. 1.00 fGm. (rn,xv) M., will relieve the exceeding pain of periodontitis.

Coffee and Belladonna, or their most active alkaloids, caffeine and atropine, are the principal physiological antidotes to morphine.

Dose of Morphine, 0.01-0.02 Gm. (gr.i-|.) Dose of Opium, 0.06 Gm. (gr. j.) Dose of Tinctura opii, 1.00 fGm. (n^^xv.) Dose of Tinctura opii et camphorata, 4.00 fGm. (f^i.) Cocaine, is obtained fi?om the leaves of Erythroxy- lon Coca, a small plant, indigenous to the mountain- ous portions of Peru and Bolivia, and now exten- sively cultivated elsewhere. The leaves have been used from time immemorial as a masticatory, by the natives of those countries, by aid of which, they are enabled to undergo fatiguing labor, with

Alkaloids. 347

apparent impunity, through the obtunding influence on the sensory nerves, and loss of the sensations of hunger, and thirst, produced by the drug.

Cocaine is a univalent base of alkaline reaction, and has the empirical formula, C17H21NO4. It forms with acids, neutcal salts, of which the Hy- drochloride (vide '' nomenclature " in Part first) is the most useful.

The distinction which cocaine hydrochloride has assumed as a local anaesthetic is well deserved. Applied to the mucous membrane, or ocular con- junctiva, or injected hypodermatically (hypoder- mically) in other parts, it causes profound aneesthesia over a limited area, sufficient for minor surgical operations. ^It causes thus, local anemia, by which probably the sensory nerves, are rendered unable to transmit normal impressions.

Cocaine hydrochloride, C17H19NO4, HCI2H2O, occurs as colorless small prismatic crystals, soluble in alcohol, water, chloroform, and vaseline, but not in ether. It is odorless, but possesses a bitter taste, followed by loss of the sense of taste, through its paralyzing influence on the peripheral extremities of the gustatory nerve.

0.65 f Gm. (rrix) of the 5 per cent, aqueous solu- tion injected into the immediate neighborhood of the apex of root, will develope sufficient local

348 Organic Chemistry.

anaesthesia to permit the painless extraction of the tooth. One of the best stimulants in collapse, which some times supervenes after the operation, is Hoff- man's Anodyne (Spiritus ^theris) in half teaspoon- ful doses, and also if necessary, subcutaneous in- jection of Atropine.

Aqueous solution of cocaine hydrochloride should be fresh, as it tends to rapidly deteriorate by fer- mentation; to overcome this latter difficulty, small proportions of salicylic acid, or carbolic acid, are added; and also as physiological antidotes, either atropine, or chloroform.

Various combinations of cocaine with other drugs, have been patented as local anaesthetics, and given suggestive names, by which coftfiding mem- bers of the profession are being extensively imposed upon. Practitioners, worthy of the name, should be possessed of more self respect than is indicated by the encouragement many of them extend to the mercenary aspect of such secret nostrums.

Cocaine is a cerebral stimulant ; it also excites the general nervous system, and increases cardiac, and respiratory movement. In small doses it is a tonic and diuretic. In Lethal doses, death occurs by simultaneous cardiac and respiratory failure.

Dose— 0.01 - 0.06 Gm. (gr. -H).

Alkaloids, etc. 349

R. Cocnina Hydrochloric 1.00 Grri. (gr, xv). Atropia Sulphas 0.01 Gm. (gr. |-). Aridi Carbullci (cryst.) 0.25 Gm. (gr. iv). Chloral Hydratis 0.20 Gm. (gr. iij). Aqua Dest. Ad. 32.00 fGin. (f^i).

M. For extraction of tooth, inject 1.00 fGm. (rrt^xv).

(Modified from formula given in " Transactions of Kan- sas D. A.")

R. Cocaina phenatis 0.10 Gm. (gr. jss). Alcoholis (ad solve) 4.00 fGm. (fsi). Aqua Dest. 6.00 fGm. (fsjss).

M. Six (6) Injections.

U. Cocaina Hydrochloris (cryst). Insert in moist cav- ity, and let remain ten minutes; for sensitive dentine.

R. Cocaina Hydrochloris 0.10 Gm. (gr. jss). Alcoholis, Chloroform! aa 4.00 fGm. (f^i).

M. Apply to Gum as a local anaesthetic (Dr. H. J. McKel- lop, from Gorgas).

350 Organic Chemistry.

CHAPTER XX.

ALKALOIDS, ETC.

AcoNiTiNE, Cg3H4 3]SrOi2?is the active alkaloid of the leaves and root of the Anconitum Napellus, or monkshood, a perennial plant, indigenous to the mountainous portions of Europe. The leaves are deeply divided; the flowers of a purple blue color, and of bell-shaped pendant form. All parts of the plant possess medicinal bitter properties, but the root is richest in active principles. Tinctura aconiti radicis is the most favored preparation.

Tincture of aconite, applied locally, causes a tingling, burning sensation, followed by numb- ness, due probably, to the paralyzing influence of aconite on the extremities of the sensory nerves. It produces sedative and anodyne effects when used topically in neuralgia and rheumatism, and relieves the pain of acute periodontitis.

When taken internally, even in full doses, aco- nite does not interfere with the normal intellectual faculties of the brain. The reflex irritability of the spinal chord is greatly diminished, cardiac ac- tion, respiratory movement, and temperature are

Alkaloids, etc. 351

reduced. It increases the flow of saliva and the secretions of the skin and kidneys.

On account of excessive slowing of the heart's action by aconite, its eraploymeut should be avoided in cases of suspected cardiac weakness.

Antidotes : Emetic, animal charcoal pulv. Tannin, hot alcoholic stimulapts, and digitalis ; also, arayl nitrite. Dose, tincture of the root, 0.06-0.30 fGm. (^^ij-v) " Aconitine, . . . 0.001 Gm. (gr. -J^)

Atropine, Cj7H23]Sr03, is the active medicinal principle of the root and leaves of atrop a belladonna, or deadly nightshade, sl perennial herbaceous plant, natural to the mountainous regions of Southern Europe and Asia, but now cultivated in this coun- try and elsewhere.

Atropine Sulphate (0^711231^03)2112804, is much more soluble in water than is the alkaloid. It is also freely soluble in alcohol, but not in ether. It is neutral in reaction, without odor, and of a bitter taste, and like aconitine, very poisonous.

Topical application of belladonna preparations is soothing and anodyne in neuralgic pains and in abcesses, and is efficacious in reducing or arresting suppurative processes, localized perspiration and the secretion of the mammary glands. Taken in- ternally, belladonna causes gentle hallucinations of a joyful character, and calming sleep. The reflex

352 Organic Chemistry.

irritability of the spinal chord is diminished, but cardiac and respiratory movements are increased.

These latter phenomena are supposed to be due to paralysis of the pneumogastric nerve ; which condition permits the sympathetic nerves to come into full play, ungoverned for the time being, by the pneumogastric, and thus exert their peculiar power. Belladonna therefore is a temporary cardiac tonic.

It induces dilatation of the pupil, by its paralyz- ing influence on the raotor-oculi nerve, which sup- plies the sphincter muscular filaments of the iris, allowing the sjunpathetic, which rules over the radiating fibers, to become extra-active in the performance of its usual function. Belladonna, checks the secretion of saliva, by selective influence on the secretory branches of the chorda tympani nerve, supplied to the submaxillary ganglion.

Antidote: Animal charcoal, vegetable astrin- gents, opium, calabar bean (physostigma veneno- sum), and tartar emetic.

Dose, Astropine 0.001 Gm. (gr. -g*^.)

Dose, Fluid Extract of root 0.06-0.30 fGm. ^Mlj-v.)

R. Extractum Bellad. fluidum Rad.

Tinctura Aconiti Radicis aa 8.00 fGm. (^ij.) Acidi Carbolici 0.30 fGm. (gttv.) Chloroformi 30.00 fGm. (fgi.)

M. S. Poison. Use as a liniment only, in painful restricted inflammation.

Alkaloids, etc. 353

Hyoscyamine, the principal alkaloid from the leaves of Hyoscyamus Niger (Henbane) a biennial plant, and Daturine from the leaves and seed of Datura Stramoniam, are chemically identical with Atropine, and possesses like the latter anodyne and antisposmodic properties.

The Datura Stramonium plant, also known as Thornapple and Jimson (Jamestown) weed, is an annual of common occurrence.

A poultice oi jimson leaves, is very efficacious in reducing the pain and swelling, in acute alveolar abscess.

Cannabin, is the most active principle of cannabis saliva or Hemp, [Cannabis Indica and C. Americana),

Cannabis sativa must not be confounded with Ajpocynum Cannabinura " Canadian , or Indian Hemp," the common Milkweed.

Cannabis sativa furnishes several preparations of more or less mystical importance.

Gunjah is the dried female flowers and leaves, sold for smoking purposes. Churrus is a resinous substance obtained by rubbing together the leaves of the plant ; and Hasheesh, or bhang, consists of the small broken stalks and leaves, mixed with aromatics and fruits.

Preparations of Cannibis Sativa taken in full dose, cause an exalted intoxication, and loss of 30

354 Organic Chemistry.

conception of time, followed by sleep, and great depression ; they act in moderate doses, as antispas- modics, and aphrodisiacs.

Applications of warm Tindura Cannabis Indica. (Dose, 2.00-4.00 fGm. (n|^xxx-lx) has been sug- gested as a local anaesthetic, in the operation of extracting teeth.

Hamamelis Vrrginica, or Witch Hazel, is a native shrub, from the bark and leaves off which, a fluid extract is obtained, possessed of tonic, astringent, and anodyne properties.

Dose of the Fluid Extract 0.06-4.00 fGm. (ntj-lx.)

R. Extractum Hamaraelidis Fluidum 4.00 fGm. (f^j.) Aqua Dest. q. s. Ad. 30.00 fGm. (fgj.)

M. S. An excellent lotion to sore gums, afte- removing salivary calculus.

Numbers of new remedies belonging mainly to the " Antiseptic " class, have been introduced during the present year.

They are generally termed by their manufac- turers, " Synthetic " (better, J.r^i^ciaQ, preparations, to distinguish them from natural products. Their names are sometimes quite fanciful; two at least, of which are ridiculously similar in sound and orthography, i. e., Europhen and Euphorin. The first is probably named in honor of Europe, and the other in recognition of the genus Euphorbia tree,

Alkalies, etc. 355

from one of the species of which, our Rubber is obtained.

EuROPHEN occurs as a jellow tasteless, odorous powder, insoluble in water, and glycerine, but solu- ble in ether, alcohol, and chloroform.

Locally, it is anaesthetic, and antiseptic, and pre- sumes to act as a substitute for Iodoform, being less poisonous, and decidedly of less unpleasant odor. It is prepared by dehydrating Isobutyl alcohol and ortho-cresol, by zinc chloride, resulting in isobutyl- orthocresol, which, dissolved in alkali, and acted upon by solution of iodine in potassium iodide, pre- cipitates as Europhen. It consists of hydro-carbon radicals, about 72 per cent, and of iodine 28 per cent, while iodoform is made up of hydro-carbon, 3 per cent and of iodine, 97 per cent.

Europhen is, therefore, comparatively very weak in iodine, which fact, however, need not prevent the manifestation of the virtues ascribed to it, inasmuch as the action of any drug, local or general, does not necessarily depend on its chemical decomposition.

EuPHORiN is a crystalline, substance structurally related to carbolic acid, and acetanilide, and is therefore easily erected on the benzene ring. It is insoluble in water, but dissolves in alcohol, and is recommended internally, as an effective anti-pyretic, and analgesic.

356 Organic Chemistry.

AsAPROL is a crystalline substance, and Diaph- THERiN, is an amorphous powder. Both are soluble in water, and possess active germicidal, and anti- septic properties.

Analysis of Teeth (Berzelius) :

Organic substance 28.0

Calcium phosphate 64.4

Calcium carbonate 5.3

Magnesium phosphate 1.0

Sodium carbonate and chloride 1.3

100.0

(Fremy).

Ash. Calcium Phos. Mag. Phos. Cal. Garb.

Enamel, 96.9 90.5 traces. 2.2

Dentine, 76.8 70.3 4.3 2.2

Cement, 67.1 60.7 1.2 2.9

[ Taken from MitcheWs Chemistry. ]

General Index.

357

GENERAL INDEX.

PAGE,

Acids 38

Acid Acetic 279

Arsenic 197

Arsenous 199

Benzoic 311

Boric 96

Butyric 273

Butylactic 292

Carbonic 93

Carbolic 307

Chromic 212

Cinnamic 326

Camphoric 323-336

Citric 296

Eugenic 324

Formic 275

Gallic 313

Glacial Acetic 279

Glyceric 298

Glycollic 291

Hydrochloric 55

Lactic 292

Malic 295

Maloric 292

Margaric 297

Metaphosphoric 83

Molybdic. 208

Nitric 67

Nitro-hydrochloric 69

Oleic 297

Oxalic 291-292-294

Oxids 46

Palmitic 297

Phosphoric 82

Permachoric 194

Phosphorous 82

Pyrophosphoric 82

Pyrotartaric 292

Salicylic 312

Selenic 79

PAGE.

Acid, Silicic 100

Stearic 297

Succinic 292

Sulfuric 75

Sulf urous.. 74

Tannic 314

Tartaric 295

Tungstic 209

Valerolactic 292

Absinthol 336

Acetic Acid 279

Acetates 280

Acids 38

Halogen 63

Acetone 261

Acetylene 304

Acetanilid 317

Aconitin.. 350

Alcohols 259-273

Aldehyds 261-274

Allyl 300

Alkaloids 341

Alum 177-180

Aluminum 175

Acetate 181

Chlorid 175-181

Hydrate 176

Oxid 178

Phosphate 179

Sulfate 177

Amalgams 155

Amids. 262

Ammonia 65

Ammonium 142

Aurate 219

Benzoate 312

Chlorid 66

Nitrate 71

Amids 261

Amins 262

358

General Index,

PAGE.

Amidogen 258

Amylene 291-302

Amyl Acetate 289

Amyl Alcohol 289

Amyl Nitrate 289

Analysis 30

Ansesthetics 71

Anisol 308

Anilin 316

Antimony 202

Acids 203

Oxids 203

Oxysulfid 204

Antimonous chlorid 2Q4

Antipyrin 317

Antiseptics 248

Aqua Regia 217

Argentum 149

Aristol 330

Arsenic 197

Arsenic Acids 199

Oxids 198

Sulfids 199

Artiads 109

Asoprol 356

Atmosphere 4

Atoms 28

Atropin 351

Attraction. 29

Auric chlorid 218

Oxid 219

Arum 214

Aurous chlorid 218

Oxid 219

Babbit's Metal ... 203

Bacilli 249

Bacteria 249

Baking Powder 295

Barium. .147

Nitrate 147

Oxids 147

Sulfate 147

Barometer 5

Basalt 175

Bases 38

Beeswax 288

Belladonna 351

PAG*.

Benzene 306

Group 311

Benzoic Acid — 311

Benzol Hydrate, 312

Beryllium 167

Benzyl Alcohol 311

Bismuth 205

Chlorid 206

Hydrate 206

Nitrate 206

Oxid 206

Oxychiorid 206

Subnitrate 206

Sulfate 206

Bleaching — 54

Blow-pipe flame 91

Borax 97-140-141

Borneol 336

Boric Acid 96

Boron 96

Britannia Metal 203

Bromin 61

Bromoform 271

Butane 267

Butter Antimony 204

Butylactic Acid 292

Cadmium 166

Caflfein 341

Calcium. 143

Benzoate 312

Carbonate 144-147

Chlorid 143

Fluorid 146

Hydrate 143

Lactate 293

Oxid 143

Phosfate 145-147

Sulfate 145

Calendula 339

Calisaya 342

Camphors 323-335

Campho-Phenic 338

Camphoric Acid 323-336

Cannabis Indica 353

Carbolic Acid 307

Carbon • 85

Compounds 252

General Index.

359

PAGE.

Carbonic Acid 93

Carbon Oxids 92-94

Disulfid 95

Carbo-IIyd rates 318

Carbom id 265

Carboxyl 260

Caryophillin 264

Capsicum 338

Caoutchouc 333

Carvacrol 329

Carvol 329

Celluloid 319

Cellulose 319

Cerium 148

Oxalate 148

Charcoal 86

Chalk 143

Chemical Affinity 29

Equations 33

Philosophy.. 103

Chemism 29

Chili Saltpeter 134

Chloral 281

Camphor.. 338

Hydrate 281

Chlorin... 53

Chlorinated Lime 46

Chloroform 268

Chloroplatinates 223

Chromium 210

Compounds 210

Cinnabar; 144

Cinnamic Acid. 326

Citric Acid 296

Cinchona 342

Clay 375-379

Cobalt 195

Compounds 195

Cohesion 29

Colloids 101

Combustion. 87

Copper 152

Compounds 153

Amalgam 155

Cocain 346

Collodion 320

Cologne 322

Corundum 175

PAGE.

Creasote 309

Creasol 310

Cresylol 310

Cream Tartar 295

Cyanogen 258

Cymene 328

Decay 245

Black 77

Brown 60

Dental 57

White 69

Dentists' Gold Foil 216

Destructive Distillation 245

Dextrin 318

Diamond 85

Disinfectants 248

Disinfection 249

Distillation 17

Dolomite 164

Dry Method 217

Dynamite 299

Earths 147

Ebonite 333

Ebullition 16

Electrolysis 224

Elements 25

Electro-negative 227

" positive 227

Electro-plating 229

EfFects of Medicines 127

Emory 175

Esters 260

Essential Oils 264-325

Equivalency 107

Variations 112

Ethane 253-267

Ethene 88-253

Alcohol 291

Erbium 148

Eremacausis 246

Ether 284

Ethers 284

Compound 280

Haloid 269

Mixed 250

Oxygen . . 259-284

860

General Index.

PAGE.

Ethine 304

Erythroxylon 346

Ethyl 277

Alcohol 277

Chlorid 286

Oxid 284

Lactates 293

Ethylene 305

Eucalyptol 328

Eugenol 324

Euphorin 354

Europhen 350

Evaporation 15

Face Powder 206

Faradic Current 231

Fatty Acids 279

Felspar 175-179

Fermentation 246

Ferric Chlorid 186

Hydrate 186

Oxid 186

Sulfate 186

Ferrous Carbonate 185

Chlorid 185

Chromite 212

lodid 185

Oxid 185

Salts 185

Sulfate 185

Sulfid. 185

Flame 89

Blow-pipe, . . ,. 95

Fluorin.. 62

Fowler's Solution 202

Fulminating Gold. 219

Fusible Alloys 205

Gallic Acid.. 313

Gallium 281

Galvanism 224

Gases 28

Gaseous Diffusion 5

Germicides 248

Glacial Acetic Acid 279

Glass. 99

Glucinum 157

Glucose 318-320

PAGE.

Glucosids.. 316

Glycerin 298

Glycerita 300

Glycolls 291

Gold ... 214

Alloys 215

Facings 220

Precipitates ^ 217

Granite . . 175

Grape Sugar 320

Graphic Formulae 110

Graphite 86

Gravitation 29.

Gums 319

Gun-cotton 319

Powder 134

Gutta-percha 333

Haemostatic 188

Halogens : 58

Hamamelis 354

Hasheesh 353

Heat 6

Atomic 104

Combustion of 91

Conduction 10

Effects 7

Expansion 7

Latent 13

Nature of 18

Radiant 22

Specific. 12

Units 50

Hemetite 183

Homologous Series 254

Hoffmann's Anodyne 285

Table 253

Hops 339

Horn Silver 149

Hydrogen 49

Chlorid 55

Permanganate 194

Peroxid 51

Hydro-Naphthal 334

Hydro-Carbons 253

Hydraulic Cement 175

Hyoscymin 353

General Index.

361

PAGE.

Illuminating Cas 87

Imidogeu 258

Iiidium.. . . . . 181

India Rubber 333

Ink 188

lodin 60

Iodoform 270

Iridium .-. 223

Iron 183

By Hydrogen 187

Iron, Cast 184

Dyalized 187

Malleable 184

Pig 184

Wrought 184

Isobu tane 267

Isomerism 263

Optical 264

Isomorphous 105

Isopentene 302

Isologous Series 254

Kaolin 179

Ketones 261-274

Labaraques Solution 140

Lactic Acid 292

Latin Abbreviations 121

Law, Avagrado 109

Even Numbers ... Ill

Periodic 233

Leucomains 341

Lead 168

Lead Acetates 169-280

Carbonate 169

Oxids 169

Light 18

Decomposition 20

lieflection 21

Refraction 19

Lime 143

Water 144

Linimentum Calcis 146

Liquids 28

Litharge 169

Lunar Caustic 149

Magnatite 183-187

31

# PAGE.

Magnesium 164

Compounds 165-166

Malic Acid 295

Malouic Acid 292

Manganese 194

Compounds 194

Margaric Acid ,. 297

Margarin 298

Marsh's Test 198

Marsh Gas 87

Masses 28

Matter, Constitution of 25

Compound 25

Elementary. 25

Materia Medica 120

Mercury 154

Compounds 156-157

Meerschaum 164

Meta-Compounds 173

Metallic Alloys 128

Classification 130

Elements 128

Properties 130

Methane 87-252-267

Methene 253

Methenyl 268

Methyl 257

Alcohol 273

Menthol 332

Metric System 123

Mica 175

Micro-Organisms 246

Mixed Ethers 259-288

Molecular Weights 105

Molecules 28-105

Compound 30

Simple 30

Molybdenum 208

Compounds 208

Monatomic Alcohols 273

Morphin , 345

Mosaic Gold 174

Monsel's Powder 187

Solution 187

Myrrh 335

Naphthalin 317-334

Nebulae 242

362

General Index,

PAGE.

Nickel 195

Compounds 196

Nicotin ... 341

Niobium 207

Nitrogeu.-. — 64

Oxids 67

Nitric Acid 67

Nitrous Ether 285

Oxid 71

Nitro-Benzene 316

Glycerin 299

Cellulose 319

Nitryl 258

Nomenclature 33

Notation 31

Nutgalls 314

Oil, Caraway 328

Cassia 325

Cinnamon 325

Cloves 324

Eucalyptus 327

Orange Flowers. 333

Peppermint 332

Sassafras 325

Turpentine 323

Wintergreen B27

Oils, Essential 264-325

Olefins 290

Oleic Acid 297

Olein 298

Opium 345

Optical Isomerism 264

Organic Acids 260

Chemistry 244

Ortho-Compounds 172

Osmium 223

Oxalic Acid 291-294

Oxidation 44

Oxids, Acid 46

Basic 46

Neutral 46

Oxygen. 43

Ethers 259-284

Ozone 46

Test 48

Palladium 223

PAGE.

Palmitic Acid ... 297

Paraflns 266

Paris Green 199

Pental ■■ 302

Perissads 109

Periodic Law 233

Table 236

Phenol 308

Phenols 332

Phenol Sodique 309

Phenacetin 317

Phenetol 308

Phenic Acid 307

Phenyl 307

Amin 316

Alcohol 307

Phosphorus 81

Compounds 82

Phosphin 83

Platinum.. .. 221

Backing 220

Compounds 222

Plumbum Acetate 169

Chromate 212

Polymerism 264

Porcelain 99-179

Teeth 180

Potassium 131

Compounds 132-137

Chromate 212

Cyanid 258

Aurate 219

Prepared Chalk 147

Primary Alcohols 273

Proof Spirit 278

Proponyl 298

Alcohol 298

Ptomains 247-341

Purple of Cassias 172-219

Propane 267

Putrefaction 245

Putty Powder 172

Pyridin 317

Pyoktanin 344

Pyrethrum 333

Pyroxylin 319

Quinin... 342

General Index.

363

PAGE.

Quinicin 317

Quick-silver 154

Radicals 114

Compound 116

Red Lead 169

Resins 223-335

Resorcin 332

Rhodium 223

Robinson's Remedy 309

Rosin 323

Ruby 175

Rules, Prescribing.. 122

Ruthenium 223

Salts 38

Salol 317

Salicylic Acid 312

Saltpeter 131-136

Samarium 148

Scandium 182

Selenium 79

Silicon 98

Silicic Acid 100

Silicon Oxid 98

Siderite 183

Silver 148

Compounds 149-150

Slate 175

Soap 298

Secondary Alcohols 273

Solar Spectrum 37

Solids 28

Sodaj Chloratse 140

Sodium 138

Arsenite 199

Compounds 138-141

Bismuthate 207

Lactate 293

Tungstatc 209

Specific Gravity 1

Heat 101

Spectrum Analysis 238

Spermaceta 288

Spores 249

Starch 318

Stearin 298

Stereo-Chemistry 263

PAGE.

Stramonium 353

Stibin 183

Strontium 14/,

Nitrate 147

Storage Batteries, 230

Sugars 320

Sucrose 320

Sublimation 17

Sulfur.. 73

Compounds 74-78

Tannic Acid 314.

Tantalum 207

Tartar 144

Tartaric Acid 295

Tartar Emetic 204

Teeth, Analysis 356

Tertiary Alcohols 273

Terpenes 322

Tellurium 80

Thallium 170

Thermometers 8

Thorium 174

Thymol 329

Tin 170

Compounds 172

Titanium 174

Toluene 306

Trinitophenol — 320

Tungsten 208

Compounds 208

Type Metal 203

Uranates 211

Uranium 209

Compounds 209

Yellow 210

Uranyl 209

Valerolactic Acid. 292

Vanadium 207

Oxids 207

Vapor Density 106

Verdigris 280

Vermilion.. 157

" Vitalized Air " 286

Volatile Oils 323

364

General Index.

PAGE.

Water 50

Glass. 90

Weights, Measures 123

Wet Method 216

White Lead 169

Witch-Hazel..... 354

Wolfram 208

Yttrium 148

PAGE,

Zinc 160

Cblorid 161

Oxid 161

Oxychlorid 162

Oxy-phosphate 162

Sulfate 163

Zirconium 174

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