\
C(SO2C2H5)2
/
C2H5
Tetronal.
Sulphonal is prepared by the oxidation of a substance obtained by
the combination of acetone and ethylmercaptan. _Veronal_ is an ethyl
compound of barbituric acid, obtained by the condensation of urea and
diethyl malonyl chloride:
NH.CO
/ \
CO C(C2H5)2
\ /
NH.CO
Veronal.
Attempts have been made to connect the physiological working of local
anæsthetics with particular constitutional groupings, as, for example,
in cocaïne; and these have led to the introduction of such substances
as the _orthoforms_, _nirvanine_, _stovaïne_, _alyhine_, _novocaïne_,
and _adrenaline_ into medicine. Adrenaline, used in conjunction with
cocaïne, has proved itself a most valuable agent in producing what is
called _lumbal anæsthesia_, whereby large sections of the lower half
of the body may be rendered completely insensitive to pain.
The study of the putrefactive changes of albuminous substances of
animal origin, induced by the activity of micro-organisms, has revealed
the existence of a number of basic nitrogenous compounds, some of
which are highly poisonous. These were classed by Selmi under the
generic name of _ptomaines_ (πτῶμα, a corpse). Brieger found that the
typhoid bacillus yielded a poisonous substance—_typhotoxine_, and that
the bacillus of tetanus forms a highly toxic basic body, _tetanine_.
All the ptomaines, however, are not poisonous. Some of them, like
_choline_ (χυλὴ, bile)—originally discovered by Strecker in bile, in
the brain, in yolk of egg, and now found to be among the products of
the putrefaction of meat and fish—have been known for some time past.
Choline was first synthetically prepared by Wurtz. _Neurine_ (νεὺρον,
nerve), a derivative of brain substance, is related to choline, and
is readily transformed into it, but differs from it in being very
poisonous. It has been synthesised by Hofmann and by Baeyer. Another
of the so-called corpse-alkaloids—_cadaverine_—has been synthetically
formed by Ladenburg. Schmiedeberg and Kopp isolated the poisonous
principle of the fungus _agaricus muscarius_, which they named
_muscarine_. It occurs with choline, from which it can be readily
obtained, among the products of the putrefaction of flesh, as well as
in many fungi.
The synthesis of the alkaloids _conine_, _atropine_, _cocaïne_,
_piperine_, and _nicotine_ has been already referred to[5] as also that
of _vanillin_, the aromatic principle of the dried fermented pods of
certain orchids; _coumarin_, the odoriferous principle of woodruff and
of the tonka bean; of _salicylic acid_, _oil of wintergreen_, _oil of
mustard_, _bitter-almond oil_, and _camphor_. _Acetic_, _succinic_,
_tartaric_, and _citric acids_ have also been artificially obtained,
and may, indeed, be built up from their elements.
[5] P. 133.
No synthesis of recent years created more widespread interest than that
of _alizarin_, first effected by Graebe and Liebermann in 1868. Its
successful commercial manufacture by Sir William Perkin in this country
and by Caro in Germany created nothing less than a revolution in one
of our leading industries, and completely destroyed a staple trade of
France, Holland, Italy, and Turkey. To procure alizarin, anthraquinone
is treated with sulphuric acid, and the product is fused with alkali
and potassium chlorate.
The remarkable industrial results attending the synthetical formation
of this madder-product naturally led to attempts to procure other
important vegetable dye-stuffs artificially, notably _indigo_.
The synthetical production of indigo has been accomplished by
the joint labours of many chemists, notably Baeyer, Heumann, and
Heymann, and the substance is now prepared on an industrial scale.
The starting-point is _naphthalene_, obtained from coal-tar. This
is converted into _phthalic acid_, which is then transformed into
_phthalimide_. The last-named substance is converted into _anthranilic
acid_, which, on treatment with monochloracetic acid, is changed into
_phenylglycin_-ortho-_carbonic acid_. On melting this with caustic
potash it yields _indoxyl acid_, which is transformed into _indoxyl_,
and thence into _indigo_.
Another method is to treat the sodium salt of phenylglycin with
sodamide, whereby _indoxyl_ is at once obtained, and this by
condensation yields _indigo blue_:
C6H5.NH.CH2.COONa + Na.NH2
Sodium salt of Sodamide.
phenylglycin.
CO
/ \
→C6H4 CH2
\ /
NH
Indoxyl.
CO CO
/ \ / \
→C6H4 C:C C6H4
\ / \ /
NH NH
Indigo blue.
Phenylglycin is obtained by the action of monochloracetic acid
on aniline, which in its turn is obtained through nitrobenzene
from benzene. Since benzene can be synthetically prepared by the
condensation of acetylene, which can be obtained by the direct union of
carbon and hydrogen at a high temperature, it is theoretically possible
to build up indigo blue from inorganic materials.
Synthetical indigo blue was placed on the market in 1897 with an
almost immediate effect on the production and price of the natural
variety, and to-day the output of Bengal indigo has fallen by more
than fifty per cent. In 1902 the amount of the natural product was
probably not greater than three million kilos, whereas in the same
year the production of synthetic indigo was upwards of five million
kilos. Before the introduction of the artificial variety the price of
pure indigo blue ranged from sixteen to twenty shillings per kilo; by
the end of 1905 it had fallen to seven or eight shillings. Mention
should be made also of _thio-indigo red_ and the _thionaphthene_
derivatives, some of which promise to be important colouring matters.
In recent years the so-called _sulphur colouring matters_ have acquired
considerable importance. Space will not permit of any fuller treatment
of the development of the manufacture of the artificial organic
colouring matters. This industry had its beginnings in England, but it
is now mainly carried on in Germany. Its importance may be gleaned
from the fact that the value of the production at the present time
amounts to not less than £12,500,000 per annum, two thirds of the
output being exported. It demands the services of battalions of skilled
chemists, and gives employment to many thousands of artisans.
Some of the most notable achievements of modern synthetical chemistry
are to be found in the work of Emil Fischer on the _sugars_ and the
_proteins_. Although the sugars have from the earliest times been
reckoned among the most characteristic products of plant life, and have
long been used as food and as sources of alcohol, comparatively little
was known until lately of their real nature and mutual relations,
in spite of numerous attempts to elucidate their constitution. Much
of the mystery surrounding their chemical history has now been
dispelled. Not only has the molecular structure of the more important
naturally occurring sugars been unravelled, but a large number of
hitherto unknown members of the various groups of the great family
to which they belong have been prepared. The first insight into the
constitution of these bodies may be said to date from the researches
of Kiliani, made about a quarter of a century ago. In 1887 Fischer
effected the synthesis of a form of fructose (fruit sugar), and
immediately afterwards of ordinary dextro-glucose (grape sugar) and
its enantiomorph lævo-glucose, and the two optically active forms
of natural fruit sugar. Since that time such sugars as arabinose,
xylose, fucose, mannose, sorbose, cane-sugar, maltose, lactose, etc.,
and the sugars existing as glucosides, have been examined, their
stereo-chemical relations defined, and synthetic methods of production
devised. Incidentally, their behaviour towards enzymes has been
studied, and the remarkable selective action of these ferments on the
various groups, due apparently to differences of configuration, has
been established, with the result that much light has been thrown
on the mechanism of enzyme action and on the general theory of
fermentation.
[Illustration: EMIL FISCHER.]
The study of the proteins by Fischer constitutes a new chapter in
bio-chemistry. Although long recognised as among the most important
of vital products, from the circumstance that they enter into the
composition of animal tissues and secretions and are essential
constituents of protoplasm, the proteins are among the worst defined
substances known to the chemist. They are difficult to separate, as
they closely resemble one another, and afford no certain indications of
individuality. Very few of them have been obtained in a form in which
their identity could be established. _Oxyhæmoglobin_ was isolated some
years ago, but the proteins of serum albumin and of egg albumin have
only recently been obtained in definite crystalline shape. All the
proteins—even the simplest of them—are of great complexity, and possess
apparently very high molecular weights. _Hæmoglobin_, for example,
appears to have approximately the formula C158H123N195O218FeS3, with
a minimum molecular weight of 16,600. Indeed, there is experimental
evidence to show that it is even considerably higher than this.
The main clues to the nature of these substances have been gained by
the systematic study of their hydrolysis, induced by reagents, or
by the action of enzymes, whereby they are found to break down into
proteoses, peptones, and a great variety of amino acids, some of which
have been synthesised. Among the proteins of simplest constitution are
the _protamines_, found in the spermatozoa of fish. They are basic
substances, especially rich in nitrogen, forming salts with platinum
chloride and certain metallic oxides. The best investigated member of
the group is _salmine_, obtained from the testicle of the salmon. The
products of its hydrolysis have been fairly well ascertained, and their
quantitative relation is such that the substance must have at least a
molecular weight of 2045, corresponding to the formula C81H155N45O18.
Many of the albumins and globulins—coagulable proteins contained in the
animal tissues—have been isolated in a more or less definite form, and
some of them have been found to yield substances akin to carbohydrates.
_Thyreoglobulin_, the globulin of the thyroid gland, has been found to
contain iodine, apparently as a normal constituent of a body which can
be isolated as a definite proximate principle. The presence of this
element is possibly connected with the curative value of the globulin
in crétinism. A considerable amount of work on the vegetable albumins
has also been done of late years; and some of them, as _edestin_ from
hemp seed and _zein_ from maize, have been obtained in definite form.
The limits of this work preclude a more detailed account of one of
the most interesting but at the same time one of the most obscure
departments of chemistry. The field has hitherto been tilled in a
somewhat intermittent and partial manner. Now that it has been entered
by chemists of experience and resourcefulness, armed with modern
methods of cultivation, it will doubtless soon yield a rich harvest of
facts, valuable alike to the physiologist and the physician.
There can be no reasonable doubt that the chemical processes of organic
life are essentially similar to those of the laboratory. The doctrine
that a special “vital force” is concerned in the production of vital
products receives no support from the teaching of modern science,
and is, indeed, contradicted by it. At the same time, it must be
admitted that we know very little as yet of the real agencies at work
in the elaboration and mutations of chemical products in the living
organism. Because we have effected the putting together of such a
product by purely laboratory processes—it may be, indeed, by a variety
of different and dissimilar processes—it by no means follows that
any one of them is identical with that actually occurring in nature.
The building up of materials in the plant by the agency of light,
for example, has not yet been imitated in the laboratory. Many plant
products are produced by the action of unorganised ferments—so-called
enzymes—none of which the chemist has succeeded in creating.
Processes akin to condensation undoubtedly occur in the living
organism; but the means by which they are effected are, in all
probability, very different from anything known to the chemist at
present. Many laboratory condensations are only accomplished at
relatively high temperatures or under considerable pressure—or, in
other words, under totally different conditions from those which obtain
in the organism.
CHAPTER XI
ON THE DEVELOPMENT OF PHYSICAL CHEMISTRY SINCE 1850
Chemistry and physics are each complementary to the other: that region
of inquiry in which they mutually overlap is known as _physical
chemistry_. Its beginnings are practically contemporaneous with those
of chemistry itself. Its main development has occurred, however, during
the last twenty-five years. Certain of its leading features have
been referred to already in connection with the establishment of the
fundamental principles of chemistry, the explanation of the so-called
gaseous laws, the constitution of gases, the relations of their volumes
to heat and pressure, and the conditions affecting their transition to
the liquid state.
As regards the molecular volumes of gases it has been shown that
simple relations are obtained when quantities represented by their
respective molecular weights are compared under identical conditions of
temperature and pressure—that is, under circumstances in which equal
numbers of molecules form the basis of comparison. The investigation
of the molecular volumes of liquids is complicated by the uncertainty
as to what constitutes in their case a valid condition of comparison.
Kopp’s assumption that a comparable condition was the temperature
at which the vapour pressures of the liquids are equal to the mean
atmospheric pressure was justified by the fact that the boiling-points
of liquids are approximately two thirds of their respective critical
temperatures. His conclusions have been confirmed and extended by
Lossen, Thorpe, and Schiff. It has been shown that the molecular
volume of a liquid—that is, the product of its relative density at the
boiling-point into its molecular weight—is in the main an additive
function modified by constitutive influences. Definite values have
thus been obtained for a number of the elements from a comparison of
homologous or similarly constituted compounds; and in certain cases
these are found to be practically identical with the values of the
elements in the uncombined state.
Considerable light has been gained during the last two decades
concerning the nature of _solution_. In its most comprehensive sense
solution means the homogeneous mixture of two or more substances: thus
the gases which exert no chemical action on each other are mutually
soluble; gases, liquids, and solids may be soluble in liquids; and,
lastly, solids maybe soluble in solids, forming what are known as
_solid solutions_. The mutual solubility of gases was studied by Dalton
who enunciated the _law of partial pressures_, which states that the
total pressure of a mixture of gases is the sum of the pressures
exerted by the individual components. This, like all the so-called
gaseous laws, is necessarily not strictly accurate under ordinary
conditions, but approximates to truth in proportion as the gases are
rarefied. Van ’t Hoff pointed out that the true partial pressures of
the components of a gaseous mixture might be experimentally ascertained
by the use of a membrane capable of effecting their separation, and on
this principle Ramsay measured the partial pressures of a mixture of
hydrogen and nitrogen contained in a palladium vessel connected with
a manometer. The palladium, at a sufficiently high temperature, is
permeable to hydrogen to the exclusion of the nitrogen. The conditions
affecting the solubility of gases in liquids were experimentally
studied by Dalton and Henry, and what is known as Henry’s law implies
that the volume of a gas dissolved by a definite volume of a liquid
is independent of the pressure; or, in other words, the density
(concentration) of the gas in solution is proportional to that in
the space above the liquid. Gases are dissolved by liquids in very
different amounts, but nothing definite is known as yet concerning the
relation between the nature of the gas and its solubility, although
certain broad generalisations are possible. Thus neutral gases—_e.g._,
hydrogen and nitrogen—are sparingly soluble, whereas gases which
show acidic or basic properties, such as the hydrogen halides, etc.,
ammonia, etc., are freely soluble. Easily liquefiable gases are also
comparatively soluble as noted by Graham.
Comparatively little is known definitely concerning the conditions
of solubility of liquids in liquids. Some liquids are wholly, others
partially miscible; and temperature and pressure appear to affect the
proportions in which the components form a homogeneous mixture. As
regards the solubility of solids in liquids, our knowledge is more
extensive, and a considerable body of literature exists on the subject,
chiefly concerning solubility of solids in water. The solubility of
a solid depends on the temperature of the solvent, and, as a rule,
increases with the temperature until a certain amount of the solid
has been dissolved, when the solution is said to be _saturated_. If
the clear saturated solution be slowly cooled, say, to a particular
temperature, it is frequently observed that more of the solid remains
in solution than is normal to that temperature; such a solution is
said to be _supersaturated_. On adding some of the solid to the
supersaturated solution the excess of the _solute_ is precipitated.
In certain cases of solubility of substances in water, increase of
temperature appears to diminish the amount dissolved. In nearly all
such cases the difference in solubility is due to differences in the
hydration of the solute. The phenomena of solid solutions have been
less perfectly investigated, but the facts appear to show that such
solutions in general tend to obey the laws regulating the solution of
liquids in liquids. Alloys may be looked upon as solid solutions; and
Roberts-Austen has shown that metals are capable of intradiffusion,
like liquids and gases respectively.
The general question of solution was greatly developed in 1885 by
Van ’t Hoff, by specially considering the case of dilute solutions. The
gaseous laws are capable of their simplest expression when the gases
are rarefied to such an extent that their molecules exert no sensible
mutual influence. The case of dilute solutions is analogous. If the
solute is present only in very small amount, the mutual influence of
its molecules is practically negligible. Under such conditions it obeys
the laws hitherto supposed to be applicable only to matter in the
gaseous state.
It may be desirable to explain how this fundamental fact was
recognised. It has long been known to the physiologist that certain
membranes are _semi-permeable_—that is, they allow of the passage of
certain liquids, and of substances in solution, to the exclusion of
others. This phenomenon is termed _osmosis_, and is of great biological
significance. It was first studied by plant-physiologists, notably by
Traube and Pfeffer. Many such semi-permeable membranes can be formed
artificially, but the most generally convenient is found to be one
consisting of copper ferrocyanide deposited on the walls of a porous
vessel.
If a vessel so prepared be filled with a solution of sugar, and be
then placed in water, the water is found to pass through the membrane,
but the membrane is impermeable to the sugar. In consequence pressure,
termed _osmotic pressure_, is found to occur within the pot, and may
be measured by suitable means. These osmotic pressures may at times be
very large: thus a 1 per cent. solution of sugar may exert a pressure
of half an atmosphere, and in the case of a solution of potassium
nitrate of the same concentration it may amount to a couple of
atmospheres.
Pfeffer determined the relation of the osmotic pressures to the
concentration of solutions of these substances, measuring the pressures
in centimetres of mercury by a manometer attached to the closed porous
vessel. His results in the case of sugar were as follows:
_Percentage _Pressure in cm.
strength (C)._ of mercury (P)._ _P/C._
1 53.5 53.5
2 101.6 50.8
4 208.2 52.1
6 307.5 51.3
It will be seen from these numbers that the ratio P/C is practically
constant—that is, _the osmotic pressure varies directly as the
concentration_. It was further found that the osmotic pressure exerted
by a solution of uniform strength increases with the temperature.
The importance, of these observations in relation to the general theory
of solution was first recognised by Van ’t Hoff. Osmotic pressure was
regarded by him as analogous to gaseous pressure. Since P/C is constant
for any one substance, and since for a definite weight of the solute
the concentration is inversely as the volume of the solution, we obtain
an equation analogous to the statement of Boyle’s law, PV = constant.
Van ’t Hoff also found that the _osmotic pressure is proportional
to the absolute temperature_, like the gaseous pressure. From these
results, in conjunction with Avogadro’s hypothesis, it follows that
_the osmotic pressure exerted by any substance in solution is the
same as it would exert if present as gas in the same volume as that
occupied by the solution, provided that the solution is so dilute that
the volume occupied by the solute is negligible in comparison with
that occupied by the solvent_. Another important consequence is that
_solutes, when present in the ratio of their molecular weights in equal
volumes of the same solvent, exert the same osmotic pressure_. Such
solutions are said to be _isomotic_ or _isotonic_. It can be proved by
thermodynamical reasoning that depression of the vapour pressure and
freezing-point of a solution is proportional to its osmotic pressure.
The significance of this relation in connection with the determination
of the molecular weight of a soluble substance has already been
referred to.[6]
[6] See pp. 70–73.
Determinations of molecular freezing-point depressions by Raoult
and others showed that certain substances exerted only about half
the osmotic pressure calculated from their known formulæ, whereas
others have abnormally high osmotic pressures. The explanation of
the discrepancies in the latter case was given in 1887 by Arrhenius,
who pointed out that _only those solutions which have abnormally
high osmotic pressures are electrically conductive_. This pregnant
observation proved to be very fruitful in suggestiveness; and the
connection between conductivity and Van ’t Hoff’s theory of solution
was developed by Arrhenius into the doctrine of _electrolytic
dissociation_ or _ionisation_—one of the most important consequences
of Faraday’s electrolytic laws, the work of Hittorf, and the kinetic
conceptions of Williamson and Clausius to which the last quarter
of a century has given rise. Arrhenius showed that not only were
free ions present in an electrically conductive solution before
electrolysis, as maintained by Clausius, but that the proportion of
molecules dissociated into ions could be calculated from measurements
of electrical conductivity, as well as from measurements of osmotic
pressure. Both methods give concordant results—a strong confirmation of
the validity of the theory. In a solution of common salt, containing a
gramme equivalent of that substance in a litre, Arrhenius calculated
that only about three tenths of the salt exists as NaCl, the remaining
seven tenths being resolved into independent ions of chlorine
(chloridion) and sodium (sodion): NaCl⇄[Na·] + Cl´, each moving freely
in all directions, like gaseous molecules. On passing the current,
electrodes placed in the solution exert a directive action on the free
ions, these alone being concerned in determining the conductivity, the
un-ionised molecules or the solvent itself exercising no influence.
Methods of determining the migration velocity of the ions have been
worked out by Hittorf, Kohlrausch, Lodge, and others.
[Illustration: SVANTE AUGUST ARRHENIUS.]
The theory of ionisation affords a satisfactory explanation of many
chemical phenomena. It accounts for the characteristic properties of
acids, and explains why different acids have varying “strengths” and
why a “weak” acid has the same “strength” as the “strong” acid at
high equivalent dilutions: in each case the acid is nearly completely
ionised—in other words, the “strength” of an acid depends on the
concentration of its hydrogen ions. So, too, the “strength” of a base
is related to the number of its hydroxyl ions. Aqueous ammonia is
relatively a “weak” base—its solution contains few hydroxyl ions. On
the other hand, caustic potash is a “strong” base—its solution, on
moderate dilution, is almost completely ionised: KOH = K· + OH´, the
positive ion being represented by one or more dots, and the negative
ion by one or more dashes. The theory accounts, too, for many phenomena
in analytical chemistry—such as why magnesia is precipitated by ammonia
only in the absence of ammonium chloride, and why sulphuretted hydrogen
throws down zinc sulphide in the absence of hydrochloric acid. It
also serves to explain many thermo-chemical facts observed by Hess,
Thomsen, and others, such as the fact that the heat of neutralisation
of the “strong” acids and bases is independent of their nature, and has
the uniform value of 13,700 calories, in agreement with the value, as
calculated by Van ’t Hoff, for the reaction H· + OH´ = H2O, deduced
from Kohlrausch’s measurements of the conductivity of water at varying
temperatures.
Certain phenomena relative to the effect of concentration (mass action)
in determining chemical change—many of which have been studied by
Ostwald and his pupils, as, for example, why two dilute solutions can
be mixed together without thermal disturbance; numerous hydrolytic
actions; the alkalinity and acidity of salts on solution; the behaviour
of the “indicators” in analysis; such phenomena as the precipitability
of common salt in aqueous solution by hydrogen chloride; the influence
of an excess of a precipitant; the varying behaviour of reagents; the
varying colour of salt solutions; the reason why water is formed in so
many reactions; why a potential difference occurs at the surface of
two electrolytic solutions, etc.—phenomena for the most part otherwise
unintelligible, are all capable of explanation by means of it.
Although, in the above statement, we have been mainly concerned with
aqueous solutions, it should be said that the theory of ionisation
is applicable to other solvents, organic and inorganic. Moreover,
it should be added, the theory has not been universally accepted as
accounting for all the phenomena of solution. Many substances form
definite hydrates which can be isolated, and it is a moot point
whether such hydrates are capable of existing in aqueous solution, as
contended by Mendeléeff, Pickering, Kahlenberg, Armstrong, and others.
Such hydrates are, however, unstable compounds, affected by temperature
changes, and dissociable on dilution in accordance with the law of
concentration (mass action). Further, there is evidence, largely based
on the work of Kohlrausch, H. C. Jones, and Lowry, to show that the
ions in aqueous solutions of electrolytes are themselves hydrated.
Limitations of space preclude further attempts to deal with the
development of physical chemistry during the last half-century, and
many important matters must remain practically unnoticed.
The subject of thermo-chemistry is mainly the creation of the last
half-century, elaborated by the labours of Hess, Andrews, Thomsen,
Favre and Silbermann, and Berthelot. The work of Wenzel and Berthollet
on the influence of molecular concentration on chemical change has
been greatly extended by Berthelot, Guldberg and Waage, Julius
Thomsen, Van ’t Hoff, Harcourt and Esson, and Le Chatelier; and the
theory of mass action and the nature of reversible processes are now
capable of definite expression, and can be proved independently by
thermo-dynamical and kinetic reasoning. The phenomena of catalysis
and the action of enzymes and of fermentation in general have
received attention from many investigators. The phenomena of gaseous
transpiration have been studied by Graham, Maxwell, and O. E. Meyer.
Thermal dissociation has been experimentally observed by Deville,
Troost, and others, and mathematically investigated by Willard Gibbs
and Van der Waals; and its analogy to electrolytic dissociation
has been established. The nature of gaseous explosions has been
investigated by Berthelot, Le Chatelier, Abel, and Dixon. Important
work has been done by Gladstone, Lorentz, Landolt, Nasini, Brühl,
and others, on the connection between the nature and constitution of
substances and their optical characters. Similar work has been done by
Sir William Perkin as regards their magnetic rotation, and by Thorpe
and Rodger with reference to their viscosity. The theory of phases,
originating with Gibbs and developed by Van der Waals and Roozeboom,
has been greatly extended. Sir J. J. Thomson and Sir J. Larmor have
elaborated an electrical theory of the atom. Barlow and Pope have
traced the relation between valency and volume, and the accurate
measurements of Groth and of Tutton have extended our knowledge of the
crystallographic relations of correlated substances.
Lastly, the whole subject of photo-chemistry, although originating with
the observations of Ingenhousz, Scheele, and Senebier, may be said
to have been studied only within our own time, notably by Bunsen and
Roscoe, Pringsheim, Pfeffer, Vogel, and Abney.
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Muir, M. M. Pattison. _History of Chemical Theories and Laws._ John
Wiley and Sons, New York, 1907.
Nernst, Walter. _Theoretical Chemistry._ Translated by C. S. Palmer.
Macmillan, 1895.
Ostwald’s _Klassiker der Exakten Wissenschaften_.
Pictet, Amé. _Vegetable Alkaloids._ Translated by H. C. Biddle. John
Wiley and Sons, New York, 1904.
Richter’s _Lexikon der Kohlenstoff Verbindungen_. Leopold Voss, Hamburg
and Leipzig.
Roscoe and Schorlemmer, _Treatise on Chemistry_. Macmillan.
Rutherford, E. _Radio-Activity._ Cambridge University Press, 1904.
Schorlemmer, Carl. _Rise and Development of Organic Chemistry._ Edited
by Arthur Smithells. Macmillan.
Schryver, S. B. _Chemistry of the Albumens._ Murray, 1906.
Soddy, F. _Radio-Activity._ The Electrician Printing and Publishing
Co., London, 1904.
Stas. _Recherches sur les Rapports réciproques des Poids Atomique,
1860–1865._
Stewart, A. W. _Recent Advances in Organic Chemistry._ Longmans, 1908.
Stewart, A. W. _Stereo Chemistry._ Longmans, 1907.
Thorpe, T. E. _Dictionary of Applied Chemistry._ Three vols. Longmans.
Thorpe, T. E. _Essays in Historical Chemistry._ Macmillan, 1902.
Travers, Morris W. _Study of Gases._ Macmillan, 1901.
Van ’t Hoff, J. H. _Arrangement of Atoms in Space._ Translated by A.
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Wurtz, Ad. _The Atomic Theory._ Translated by E. Cleminshaw. Kegan
Paul.
INDEX
Abel, 184
Abney, 185
Absolute zero, 97
Acetanilide, 159
Aceto-acetic ester, 148
Actinium, 59
Adrenaline, 160
Agurin, 158
Alizarin, 162
Alkaloids, 132
Allyl alcohol, 4
Alyhine, 160
Ammonium chloride, dissociation of, 66
Ampère, 62
Anderson, 133
Andrews, 70, 95, 183
Aniline blue, 4
Aniline purple, 4
Antimony, origin of name, 28
Antipyrin, 159
Argon, 43, 45, 46
Argyrodite, 37
Armstrong, E. F., 151
Armstrong, H. E., 183
Aromatic compounds, 121, 123
Arrhenius, 179, 180
Arsine-dimethyl, 20
Artiads, 116
Asymmetry, 141
Atmolysis, 84
Atomic value, 114
Atomic weight, determination of, 75
Atomicity, 114
Atropine, 135, 162
its synthesis 135
Australene, 130
Autoracemisation, 144
Avogadro, 62
his hypothesis, 63
Baeyer, 125, 129, 161, 163
Balard, 139
Baly, 129, 151
Bamberger, 147
Barbier, 154
Barlow, 184
Basarow, 157
Basicity, 16
Becquerel, Henri, 52
Behrend, 157
Benzene, 123
its constitution, 123 _et seq._, 128
Benzidam, 3
Berberine, 136
Bernoulli, Daniel, 82
Berthelot, Daniel, 82, 183, 184
Berthollet, 183
Berzelius, 63
Biot, 138
Bitter almond oil, 7
Blagden, Sir Charles, 72
Boisbaudran, Lecoq de, 36, 38, 39
Boltzmann, 83
Bone oil, 133
Boron, specific heat of, 71
Boyle’s law, 84–87
Brauner, 33
Bredt, 129, 130
Brieger, 161
Brühl, 149, 151
Bunsen, Robert W., 18, 34, 43, 185
Bunsen burner, 22
Cacodyl, 20
Cadaverine, 161
Cæsium, 21, 34
Caffeine, 157
Cahours, 4, 132
Cailletet, 96
Camphene, 131
Camphor, 130, 131, 162
Cannizzaro, Stanislao, 64, 79
Carbon, atomic weight of, 75
specific heat of, 71
tetravalency of, 115
Carbon carbonyl, 155
Carbon suboxide, 155
Carnelley, 108
Carnolite, 58
Cavendish, 43, 45
Cayley, 120
de Chancourtois, 102
Chloral hydrate, 159
Choline, 161
Cinchonine, 137
Clausius, 83, 179
Cleve, 38, 47
Cleveite, 47
Cocaïne, 136, 162
Codeine, 137
Coindet, 8
Collie, 49, 128
Condensation, 152
Conine, 162
Conservation of mass, law of, 78
Coumarin, 132, 162
Critical point, 94
Critical pressure, 95
Crookes, Sir William, 35, 40, 75
Curie, Marie, 55
Cyanic acid, 7
Cyanuric acid, 7
Debierne, 59
Decipium, 40
Delafontaine, 49
Demarçay, 30
Desch, 151
Deville, 184
Dewar, 71, 96, 127
Dexter, 157
Didymium, 40
Digitalis, 10
Disintegration theory, 54
Dixon, 184
Dobbie, 151
Doebner, 134
Dumas, Jean B. A., 8, 9, 30, 31, 63, 75, 102, 130
Duppa, 148
Dysprosium, 38
Edestin, 169
Electrolysis, 179
Elements, nomenclature of, 27
Emanation from Radium, 58
Emanium, 60
Enantiomorphism, 140
Enzymes, 144
Ether, discovery of its constitution, 12, 17
Etherin theory, 10
Europium, 39
Favre, 183
Fenton’s reagent, 154
Findlay, 151
Fischer, Emil, 158, 165, _et seq._
Fittig, 153
Fluorine, 33, 34
Formulæ, chemical, significance of, 68
Frankland, 114, 116, 148
Fuchsine, 4
Fumaric acid, 146
Gadolinium, 39
Gallium, 36, 107
Gases, kinetic theory of, 83
law of diffusion of, 84, 89
liquefaction of, 94
molecular theory of, 79
Gas-mantles, 40
Gay Lussac, 63, 80
Geometrical isomerism, 146, 147
Gerhardt, 79, 113
Germanium, 37, 107
Geuther, 148
Gibbs, Willard, 184
Giesel, 60
Gladstone, 30, 102, 184
Gmelin, 7, 63, 102
Gore, 33
Graebe, 162
Graham, Thomas, 2, 14, 23, 29, 83
Grignard’s reagent, 154
Groth, 184
Guldberg, 183
Guye, 81
Haarmann, 132
Hæmoglobin, 168
Hantzsch, 147
Hartley, 151
Haüy, 139
Heliotropin, 132
Helium, 43, 47, 49
Helmholtz, 117
Henry’s law, 173
Hermann, 26
Herschel, 140
Hess, 181, 183
Heumann, 163
Heymann, 163
Hillebrand, 47
Hittorf, 179
Hofmann, August W., 3, 67, 133, 161
Holmium, 38
Hoogewerff, 133
Horbaczewski, 157
Hübner, 127
Hydrogenium, 16
Hyoscyamine, 135
Ilmenium, 26
Indigo, 162, 164
Indigo blue, 163
Indium, 36
Ingenhousz, 185
Ionisation, 178
Ionium, 58
Ionone, 132
Irone, 132
Isoborneol, 131
Isoconine, 134
Isoquinoline, 133
Isotonic solutions, 178
Jones, H. C., 183
Jones, H. O., 147
Kahlenberg, 183
Kammerlingh Onnes, 49, 97
Kekulé, Friedrich August, 23, 113, 114, 121, 123, 125, 153
Kiliani, 165
Kipping, 147
Kirchhoff, 21
Knorr, 128, 151, 159
Koenigs, 133
Kohlrausch, 182, 183
Komppa, 129
Kopp, 172
Körner, 127
Krüss, 40
Krypton, 43, 50
Krystallin, 3
Kundt, 46
Laar, 149
Lactic acid, spatial representation of, 141
Ladenburg, 127, 134, 147, 161
Lamy, 35
Landolt, 78, 184
Langlet, 49
Larmor, Sir J., 184
Lauder, 151
Laurent, 79
Le Bel, 143, 147, 148
Leduc, 80, 81
Le Royer, 8
Leucol, 133
Liebermann, 162
Liebig, Justus von, 5
Linnemann, 127
Liquid diffusion, 16
Liquids, molecular volumes of, 172
Lossen, 172
Lowry, 151, 183
Low temperature research, 97, 39
Lutecium, 89
Magenta, 4
Magnus, 79
Maleic acid, 146
Mansfield, 3
Marignac, 39, 75
Mauve, 4
Maxwell, 83
Medlock, 3
Mellitic acid, 7
Membranes, semi-permeable, 176
Mendeléeff, 30, 102, 109, 183
Mercury forms a monatomic gas, 71, 92
Metaphosphoric acid, 14
Meyer Lothar, 103
Meyer, Victor, 67, 147
Mitscherlich, 63, 138
Moissan, 33
Molecule, integral, 62
Molecules, their number, 93
their size, 93
Monium, 40
Morley, 80
Morphine, 137
Mosander, 39
Multirotation, 145
Muscarine, 161
Muspratt, 4
Mutarotation, 145
Naphthalene, 163
Narceïne, 136
Narcotine, 136
Nasini, 184
Natanson, 157
Neodymium, 39
Neon, 43, 50
Neoytterbium, 38
Neurine, 161
Newlands, 102
Nicotine, 135, 162
Nilson, 37, 40, 107
Nirvanine, 160
Nitrogen compounds, stereo-isomerism of, 147
Novocaïne, 160
Odling, 30, 114
Oil of wintergreen, 162
Olszewki, 96
Opianic acid, 136
Organic synthesis, 152
Orthoforms, 160
Osmotic pressure, 176
Ostwald, 182
Oxyhæmoglobin, 167
Ozone, 70
its symbol, 70
Papaverine, 136
Partial pressure, law of, 173
Pasteur, 139
Peachey, 148
Pelopium, 26
Penny, 75
Periodic law, 101
Perissads, 116
Perkin, Sir William, 3, 129, 131, 132, 162
Pettenkofer, 30
Pfeffer, 176, 185
Phenacetin, 159
Phenylglycin, 163
Phosphorous oxide, molecular weight of, 73
Phosphorus pentachloride, 66
Phosphorus pentafluoride, 67
Phthalic acid, 163
Pickering, 183
Pictet, 96, 135
Pinene, 130, 131
Pinner, 135
Piperine, 134, 162
Plattner, 35
Playfair, 20
Pollucite, 35
Pope, 147, 184
Posselt, 135
Praseodymium, 38
Pringsheim, 185
Protamines, 168
Proteins, 165
Prout’s law, an illusion, 76
Ptomaines, 161
Pyridine, 133
Quinine, 137
Quinoline, 133
Racemic acid, 140
Racemism, 143
Radio-thorium, 60
Radium, atomic weight of, 58
discovery of, 55
disintegration of, 58
emanation, 58
extraction of, 55
Radium chloride, 57
Ramsay, Sir William, 44, 47, 173
Raoult, 72, 178
Rayleigh, Lord, 44, 81
Regnault, 43, 79, 88, 157
Reich, 36
Reimann, 135
Richards, Theodore, 77
Richter, 36
Rodger, 184
Roosen, 157
Roozeboom, 184
Rosaniline, 4
Roscoe, 21, 30, 117, 185
Rose, 26
Rotatory power, 144
Rubidium, 21, 34
Runge, 133
Rutherford, 59
Salicylic acid, 162
Salmine, 168
Samarium, 40
Sarcine, 157
Sarcolactic acid, 140
Saturated solutions, 174
Saussure, 43
Scandium, 37, 107
Scheele, 33, 140, 185
Schiff, 172
Schischkoff, 21
Schmidt, 83
Schmiedeberg, 161
Scott, 80
Selmi, 161
Senebier, 185
Sesquiterpenes, 129
Silbermann, 183
Silicon, specific heat of, 71
Skraup, 133
Solute, 175
influence of, on boiling-point, 71
on freezing-point, 71
on vapour pressure, 73
Sonstadt, 153
Soret, 70
Spectrum analysis, 21
Stas, 75
Steric hindrance, 151
Stovaïne, 160
Strecker, 102, 158, 161
Sugars, 165
Sulphonal, 159
Supersaturated solutions, 174
Tait, 70
Tautomerism, 149
Terebenthene, 130
Terpenes, 129
Tetanine, 161
Tetronal, 159
Thallium, 35
Thebaine, 137
Thénard, 43
Theobromine, 157
Thioacetic acid, 127
Thomsen, Julius, 51, 108, 183
Thomson, Sir J. J., 184
Thomson, Thomas, 3
Thorium, 60
Thorpe, 172, 184
Thulium, 38
Thyreoglobulin, 169
Tiemann, 129, 132
Traube, 176
Travers, 50
Trional, 159
Triphenylrosaniline, 4
Troost, 184
Turner, Edward, 2, 14, 75
Turpentine, oil of, 129
Tutton, 184
Type theory, 18
Typhotoxine, 161
Unverdorben, 3
Uranium, 54
Uranium │x│, 54
Urbain, 40
Urea, synthesis of, 157, 158
Uric acid, 158
Valency, 112
Vanadium, 30
Van der Waals, 95, 184
Van Dorp, 133
Vanillin, 132, 162
Van ’t Hoff, 117, 141, 145, 147, 173, 177
Veronal, 159
Verquin, 4
Victorium, 40
“Vital force” doctrine, 169
Vogel, 185
Von Miller, 134
Waage, 183
Wallach, 129
Warburg, 46
Waterston, 83
Weber, 71
Weisbach, 37
Welsbach, Auer von, 38
Werner, 147
Williamson, Alexander W., 14, 16, 113
Winkler, 107
Wintergreen, oil of, 132
Wislicenus, 140
Wöhler, Friedrich, 5, 7
Wollaston, 63
Wroblewski, 96
Wurtz, 153
Xanthine, 157
Xenon, 43, 51
Zein, 169
Zinin, 3
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Transcriber’s Notes
Punctuation and spelling were made consistent when a predominant
preference was found in this book; otherwise they were not changed.
Simple typographical errors were corrected; occasional unbalanced
quotation marks retained.
Ambiguous hyphens at the ends of lines were retained; occurrences of
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Index not checked for proper alphabetization or correct page references.
The table on page 105 has been split into three parts to keep it narrow.