Transcriber’s Note: Italic text is indicated by _underscores_; boldface
text is indicated by =equals signs=. There is an actual equals sign in
the list on page 131.
_A HISTORY OF THE SCIENCES_
HISTORY
OF
CHEMISTRY
BY
SIR EDWARD THORPE,
C.B., LL.D., F.R.S.
AUTHOR OF “ESSAYS IN HISTORICAL CHEMISTRY,” “HUMPHRY DAVY:
POET AND PHILOSOPHER,” “JOSEPH PRIESTLEY,” ETC., ETC.
TWO VOLUMES
I.
From the Earliest Times to the Middle of the
Nineteenth Century
_WITH ILLUSTRATIONS_
G. P. PUTNAM’S SONS
NEW YORK AND LONDON
The Knickerbocker Press
1909
COPYRIGHT, 1909, BY
G. P. PUTNAM’S SONS
This series is published in London by
THE RATIONALIST PRESS ASSOCIATION, LIMITED
PUBLISHERS’ NOTE
A HISTORY OF THE SCIENCES has been planned to present for the
information of the general public a historic record of the great
divisions of science. Each volume is the work of a writer who is
accepted as an authority on his own subject-matter. The books are
not to be considered as primers, but present thoroughly digested
information on the relations borne by each great division of science
to the changes in human ideas and to the intellectual development
of mankind. The monographs explain how the principal scientific
discoveries have been arrived at and the names of the workers to whom
such discoveries are due.
The books will comprise each about 200 pages. Each volume will contain
from 12 to 16 illustrations, including portraits of the discoverers and
explanatory views and diagrams. Each volume contains also a concise but
comprehensive bibliography of the subject-matter. The following volumes
will be issued during the course of the autumn of 1909.
=The History of Astronomy.=
By GEORGE FORBES, M.A., F.R.S., M. Inst. C.E.; author of _The
Transit of Venus_, etc.
=The History of Chemistry: Vol. I. circa 2000 B.C. to 1850 A.D.
Vol. II. 1850 A.D. to date.=
By SIR EDWARD THORPE, C.B., LL.D., F.R.S., Director of the
Government Laboratories, London; Professor-elect and Director
of the Chemical Laboratories of the Imperial College of Science
and Technology; author of _A Dictionary of Applied Chemistry_.
_To be followed by_:
=The History of Geography.=
By Dr. JOHN SCOTT KELTIE, F.R.G.S., F.S.S., F.S.A., Hon. Mem.
Geographical Societies of Paris, Berlin, Rome, Brussels,
Amsterdam, Geneva, etc.; author of _Report on Geographical
Education_, _Applied Geography_.
=The History of Geology.=
By HORACE B. WOODWARD, F.R.S., F.G.S., Assistant-Director of
Geological Survey of England and Wales; author of _The Geology
of England and Wales_, etc.
=The History of Anthropology.=
By A. C. HADDON, M.A., Sc.D., F.R.S., Lecturer in Ethnology,
Cambridge and London; author of _Study of Man_, _Magic and
Fetishism_, etc.
=The History of Old Testament Criticism.=
By ARCHIBALD DUFF, Professor of Hebrew and Old Testament Theology
in the United College, Bradford; author of _Theology and
Ethics of the Hebrews_, _Modern Old Testament Theology_, etc.
=The History of New Testament Criticism.=
By F. C. CONYBEARE, M.A., late Fellow and Praelector of Univ.
Coll., Oxford; Fellow of the British Academy; Doctor of
Theology, _honoris causa_, of Giessen; Officer d’ Academie;
author of _Old Armenian Texts of Revelation_, etc.
Further volumes are in plan on the following subjects:
=Mathematics and Mechanics.=
=Molecular Physics, Heat, Life, and Electricity.=
=Human Physiology, Embryology, and Heredity.=
=Acoustics, Harmonics, and the Physiology of Hearing, together with
Optics Chromatics, and Physiology of Seeing.=
=Psychology, Analytic, Comparative, and Experimental.=
=Sociology and Economics.=
=Ethics.=
=Comparative Philology.=
=Criticism, Historical Research, and Legends.=
=Comparative Mythology and the Science of Religions.=
=The Criticism of Ecclesiastical Institutions.=
=Culture, Moral and Intellectual, as Reflected in Imaginative
Literature and in the Fine Arts.=
=Logic.=
=Philosophy.=
=Education.=
CONTENTS
CHAPTER I PAGE
THE CHEMISTRY OF THE ANCIENTS 1
Egypt, the alleged birthplace of chemistry. Origin of the word
“chemistry.” Chemical arts known to the ancients. Metallurgy
of the ancients. Chemical products of the Chinese, Egyptians,
Greeks, and Romans.
CHAPTER II
THE CHEMICAL PHILOSOPHY OF THE ANCIENTS 19
Ancient speculations as to the origin and nature of matter.
Water the primal principle. Thales of Miletus. Persistency
of his doctrine. Its influence on science. Theories of
Anaximenes, Herakleitos, and Pherekides. Fire as the primal
principle. The conception of four primal principles—fire,
air, water, and earth. Deification of these by Empedocles.
Plato and Aristotle. The doctrine of the four Elements.
Influence of the Peripatetic Philosophy on science. Arabian
science. Influence of the Moors in Spain. Atomic conceptions
of Anaxagoras, Leukippos, and Demokritos. Germs of the atomic
theory.
CHAPTER III
ALCHEMY 28
Influence of the Hellenic mind on the development of
chemistry. Origin of the idea of the transmutation of
metals. Philosophical foundation for the belief in alchemy.
Alchemistic theory of the nature of metals. Origin of the
conception of the Philosopher’s Stone. Geber. Association of
alchemy with astrology. Rhazes. Avicenna. Chemical processes
and substances known to the Arabian chemists. The Western
Alchemists. Albertus Magnus. Roger Bacon. Raymond Lully.
Arnoldus Villanovanus. Johannes de Rupecissa. George Ripley.
Basil Valentine.
CHAPTER IV
THE PHILOSOPHER’S STONE 46
Alchemy in the Middle Ages. Association of religion with
alchemy by the Christian Church. Alleged nature of the
Philosopher’s Stone. Its character described. Its power.
The Universal Medicine. The Elixir of Youth. The Alkahest.
Opponents of alchemy: Erastius, Conringius, and Kircher.
“The Hermes of Germany”: Rudolph II. Christian princes who
had dealings with alchemists. Fate of certain alchemists.
Persistency of alchemy and hermetic societies. Lord Bacon on
alchemy.
CHAPTER V
IATRO-CHEMISTRY 57
Theories of the iatro-chemists. Paracelsus. Doctrine of the
_tria prima_. The Paracelsian harmonies. Libavius. Van
Helmont. Sylvius. Willis. Services of iatro-chemistry
to science. Influence of iatro-chemistry on technology.
Agricola. Palissy. Glauber. Chemical products made known by
the alchemists.
CHAPTER VI
“THE SCEPTICAL CHEMIST”: THE DAWN OF SCIENTIFIC CHEMISTRY 70
The foundation of the Royal Society and other scientific
academies. The appearance of “The Sceptical Chemist”: its
attack on the doctrines of the Spagyrists. Boyle: his life
and character. His services to learning. Kunkel. Becher.
Mayow. Lemery. Homberg. Boerhaave. Stephen Hales.
CHAPTER VII
PHLOGISTONISM 91
Becher’s hypothesis of the _Terra Pinguis_. Its development
into the theory of phlogiston. Stahl. Phlogiston, primarily
a theory of combustion, becomes a theory of chemistry. Its
general acceptance in Europe until the last quarter of the
eighteenth century. Prominent phlogistians. Pott. Marggraf.
Scheele: his discoveries. Duhamel. Macquer. Black: his
essay on _Magnesia Alba_. Recognition of the individuality
of carbon dioxide. Priestley: his life and character. His
discoveries in pneumatic chemistry. His observations on
the influence of vegetable life on the character of the
atmosphere. Cavendish: his life and work. Discovery of
composition of water. Influence of phlogistonism on the
development of chemistry. Advances made during the period of
phlogistonism.
CHAPTER VIII
LAVOISIER AND LA RÉVOLUTION CHIMIQUE 109
Downfall of phlogistonism. Lavoisier: his life and work. His
death. _Le principe oxygine._ Principle of the conservation
of matter. Chemistry a science of quantitative relations.
Prominent anti-phlogistians. Berthollet. The _Statique
Chimique_. Fourcroy. Vauquelin. Klaproth. Proust.
CHAPTER IX
THE ATOMIC THEORY 123
The atomic hypotheses of the ancients. Newton. Bergmann.
Lavoisier. Richter. Stochiometry. John Dalton: sketch of his
life and character. How he was led to his explanation of the
laws of chemical combination. The _New System of Chemical
Philosophy_. Reception of his theory by Davy and Wollaston.
Berzelius: his life and work. His services to chemistry.
First accurate series of atomic weight determinations.
Avogadro. Prout’s hypothesis.
CHAPTER X
THE BEGINNINGS OF ELECTRO-CHEMISTRY 140
The Voltaic Pile. Electrolytic decomposition of water by
Nicholson and Carlisle. Application of voltaic electricity
to the decomposition of the alkalis by Davy. His life and
work. Wollaston: his life and work. Electro-chemical system
of Berzelius. Dualism. Berzelius reforms chemical notation
and nomenclature. Gay Lussac: his life and work. Thénard: his
life and work. Faraday and the law of definite electrolytic
action.
CHAPTER XI
THE FOUNDATIONS OF ORGANIC CHEMISTRY 154
Nicolas Lemery divides chemistry into its two main branches
of inorganic and organic chemistry. State of knowledge of
products of organic origin during the early years of the
nineteenth century. Animal chemistry. Doctrine of vital
force. Wöhler’s synthesis of urea. Organic chemistry is the
chemistry of the carbon compounds. Early attempts at organic
analysis by Lavoisier, Berzelius, Gay Lussac, and Thénard.
Liebig. Discovery of _isomerism_ and _allotropy_. Cyanogen.
Theory of compound radicals. Etherin theory of Dumas and
Boullay. Memoir of Liebig and Wöhler on oil of bitter
almonds. Benzoyl theory. Investigation of alkarsin by Bunsen.
Cacodyl. Discovery of zinc ethyl by Frankland.
CHAPTER XII
THE RISE OF PHYSICAL CHEMISTRY 170
Relations of chemistry to physics. Relations of heat
to chemical phenomena. Improvements in the mercurial
thermometer. Newton. Shuckburgh. Brooke Taylor. Cavendish.
Black. Discovery of latent heat by Black. Discovery of
specific heat. Experiments of Lavoisier and Laplace. Law
of Dulong and Petit: its value in determining atomic
weights. Specific heat of compounds. Neumann. Discovery of
isomorphism by Mitscherlich. Foreshadowing of the kinetic
theory of gases. Discovery of the law of gaseous diffusion by
Graham. Liquefaction of gases. Monge and Clouet. Northmore.
Faraday. Value of a knowledge of weights of unit volumes of
gases in determining their molecular weights. Methods of
vapour-determination by Dumas and Gay Lussac. Dalton and
Henry’s law of gaseous solubility. Work of Schröder and Kopp
on volume relations of liquids and solids. Connection between
the chemical nature of a liquid and its boiling-point.
BIBLIOGRAPHY 183
INDEX 187
HISTORY OF CHEMISTRY
CHAPTER I
THE CHEMISTRY OF THE ANCIENTS
Chemistry, as an art, was practised thousands of years before the
Christian era; as a science, it dates no further back than the middle
of the seventeenth century. The monumental records of Egypt and the
accounts left us by Herodotus and other writers show that the ancient
Egyptians, among the earliest nations of whom we have any records,
had a considerable knowledge of processes essentially chemical in
their nature. Their priests were adepts in certain chemical arts, and
chemical laboratories were occasionally attached to their temples, as
at Thebes, Memphis, and Heliopolis. It is to be supposed, too, that
in a cultured class, as the priesthood undoubtedly was, there would
be now and again curious and ingenious persons who would speculate on
the nature and causes of the phenomena which they observed. But there
is no certain evidence that the Egyptians ever pursued chemistry
in the spirit of science, or even in the manner in which they and
the Chaldæans followed, for example, astronomy or mathematics. The
operations of chemistry as performed by them were of the nature of
manufacturing processes, empirical in character and utilitarian in
result. It was comparatively late in the world’s history that men were
found willing to occupy themselves in chemical pursuits in order to
gain an insight into the nature of chemical change, and to learn the
causes and conditions of its action.
Although we have cited the ancient Egyptians as practising the chemical
arts, there is no proof that these arts actually originated with them.
China, India, Chaldæa have each in turn been regarded as the birthplace
of the various technical processes from which chemistry may be said to
have taken its rise. Nevertheless, it is mainly from Egyptian records,
or from writings avowedly based on information from Egyptian sources,
that such knowledge as we possess of the earliest chemical processes is
derived. It is significant that the word “chemistry” has its origin in
_chemi_, “the black land,” the ancient name for Egypt. The art itself
was constantly spoken of as the “Egyptian art.”
“The word _chemistry_,” says Boerhaave in the Prolegomena of his _New
Method of Chemistry_ (Shaw and Chambers’s translation, London, 1727),
in _Greek_ should be wrote χημíα, and in _Latin_ and _English_
_chemia_ and _chemistry_; not as usual, _chymia_ and _chymistry_.
The first author in whom the word is found is _Plutarch_, who
lived under the Emperors _Domitian_, _Nerva_, and _Trajan_. That
philosopher, in his treatise of _Isis_ and _Osiris_, takes occasion
to observe that _Egypt, in the sacred dialect of the country, was
called by the same name as the_ black _of the eye_—viz., χημíα—by
which he seems to intimate that the word _chemia_ in the _Egyptian_
language signified black, and that the country, _Egypt_, might take
its denomination from the _blackness_ of the soil.
But [continues Boerhaave] the etymology and grammatical
signification of the name is not so easily dispatched. The critics
and antiquaries, among whom it has been a great subject of inquiry,
will not let it pass without some further disquisition. Instead of
_black_, some will have it originally denote _secret_, or _occult_;
and hence derive it from the _Hebrew_ _chaman_, or _haman_—a
_mystery_, whose radix is _cham_. And, accordingly, _Plutarch_
observes that _Egypt_, in the same sacred dialect, is sometimes
wrote in _Greek_ χαμíα—_chamia_; whence the word is easily deduced
further from _Cham_, eldest son of Noah, by whom Egypt was first
peopled after the deluge, and from whom, in the Scripture style,
it is called the _land of Cham_, or _Chem_. Now, that _chaman_,
or _haman_, properly signifies _secret_ appears from the same
_Plutarch_, who, mentioning an ancient author named _Menethes
Sibonita_, who had asserted that _Ammon_ and _Hammon_ were used
to denote the god of _Egypt_, _Plutarch_ takes this occasion to
observe that in the _Egyptian_ language anything secret or occult
was called by the same name, ἅμμον—_Hammon_.... Lastly, the learned
_Bochart_, keeping to the same sense of the word, chooses to derive
it from the _Arabic_ _chema_, or _kema_—to _hide_; adding that
there is an _Arabic_ book of secrets called by the same name _Kemi_.
From the whole of which Boerhaave gathers that chemistry was thus
originally denominated because it was considered of old as “not fit to
be divulged to the populace, but treasured up as a religious _secret_.”
If we are to credit Zozimus the Panopolite, who is said to have lived
about the beginning of the fifth century, there were sound reasons for
thus treasuring up chemistry as a religious secret, since, as it sprang
from the _pretium amoris_, its origin was not too reputable. “What the
divine writings relate is that the angels, enflamed with the desire
of women, instructed ’em in all the works and mysteries of nature.
For which indiscretion they were excluded heaven, as having taught
men things unfit for ’em to know.” And Scaliger asserts that “Hermes
testifies as much; and all our learning, both open and occult, confirms
the account.” But who Hermes was, adds that author, is hard to say, for
none of his writings has survived to our age, “that lately published in
Italy under the name of _Hermes Trismegistus_ being a manifest forgery.”
This legend of the “feministic” origin of chemistry is in reality much
older than the fifth century of our era, and is but a variant of that
which, according to Jewish writers, led to the expulsion of man from
Paradise. A similar myth was current among the Phœnicians, Persians,
Greeks, and Magi. We trace it in the legend of Sibylla, who demanded,
as the price of her favour to Phœbus, not only length of years,
but a knowledge of the divine _arcanum_. Some of the ecclesiastics
who elaborated these myths are particular in their accounts of the
mysteries thus imparted. They included the use of charms, a knowledge
of gold and silver and precious stones, the art of dyeing, of painting
the eyebrows, etc.—the kind of _arcana_, in fact, which women in all
ages were presumably most keen to know. It is, however, significant
that in all allusions to _chemia_, even after the translation of
the seat of the Roman Empire to Constantinople, it is implied that
a knowledge of it was a sacred mystery to be known only to the
priesthood, and jealously guarded by them. It was characteristic of
writers who had affixed an eternal stigma on Eve to make the sex in
general answerable for an illicit knowledge of “things unfit for men to
know.”
For, in reality, chemistry originated with men, and it was not so much
in the love of women as of wine that it took its rise.
The manufacture of _alcohol_ by processes of fermentation is probably
the oldest of the chemical arts. The word _wine_ means, in fact, a
_product of fermentation_. Mosaic history relates that Noah, soon
after he got to dry land, “planted a vineyard and drank of the wine,”
with results that would appear to show that the potency of wine
was not unfamiliar to him. Diodorus Siculus, who studied Egyptian
antiquities when Egypt was a Roman province, states that the ancient
Egyptians ascribed the origin of wine to Osiris. It was a sacrificial
offering even in the earliest times, as was bread. Wine seems to have
been prepared by the Chinese as far back as the time of the Emperor
Yü, _circa_ 2220 B.C. Beer was manufactured in Egypt in the time of
Senwosret III. (Sesostris) B.C. 1880.
The Egyptians were skilled in dyeing and in the manufacture of
leather, and in the production and working of metals and alloys. They
were familiar with the methods of tempering iron. They made glass,
artificial gems, and enamels. The oldest known enamel was found as an
amulet on the Egyptian Queen Aahotep (1700 B.C.), and glass beads were
made before the time of Thutmosis III. (1475 B.C.). The Jews knew of
gold, silver, copper, iron, lead, and tin. Indeed, it is through them
and the Phœnicians, who were among the earliest of traders, that Europe
was gradually made acquainted with many technical products of Eastern
origin.
The beginnings of the art of extracting and working of metals are
lost in the mists of antiquity; the chemistry of metals, indeed, has
been said to be almost coeval with mankind. Diodorus Siculus found
traditions in Egypt as to the first inventor of metallurgical processes
identical with that of the son of Lamech and Zillah, Tubal-cain, or
Tuval-cain, of the Hebrews—the Vulcan of the Romans.
_Gold_ was undoubtedly one of the earliest metals to be made use of by
men, as it probably was one of the first to be discovered. It occurs
free in nature, and is met with in many rocks and in the sands of
rivers. Its colour, lustre, and density would early attract attention
to it; and its malleability and ductility and the ease with which it
could be fashioned, together with its unalterability, would render it
valuable. Ethiopian and Nubian gold were known from the earliest times,
and quartz crushing and gold washing were practised by the Egyptians.
Representations of these processes have been found on Egyptian
tombs dating from 2500 B.C. Gold-wire was used by the Egyptians for
embroidery, and they practised plating, gilding, and inlaying as far
back as 2000 B.C.
_Silver_ also was employed by them, and appears, like gold, to have
been coined into money. It was originally known as “white gold.”
Some of the oldest coins in existence are alloys of silver and gold,
obtained probably by the fusion of naturally occurring argentiferous
gold, such as the pale gold of the Pactolus. Such an alloy was termed
_electrum_, from its resemblance in colour to amber.
_Copper_ is also found to a limited extent in the metallic state, but
probably the greater part of that used by the ancients was obtained
from its ores, which are comparatively abundant and readily smelted.
It was also used for coinage by the Egyptians, and was fashioned by
them into a variety of utensils and implements. The older writers drew
no clear distinction between copper, bronze, and brass, and the terms
designating them—_æs_ and χαλκός—are frequently employed; as by Pliny,
indiscriminately. The statement in Deut. viii. 9—“Out of whose hills
thou mayest dig brass”—obviously cannot mean an alloy of copper and
zinc, since this does not occur naturally.
Pure copper is too soft a metal to be used for swords and cutting
instruments, but copper ores frequently contain associated metals, as,
for example, tin, which would confer upon the copper the necessary
hardness to enable it to be fashioned into weapons. Such copper would
be of the character of bronze, and it was known to the early workers
that the nature of the metal was greatly modified by the selection
of ores from particular localities. It was comparatively late in the
metallurgical history of copper that bronze was produced by knowingly
adding tin to the metal.
Copper was largely used by the Romans, who obtained it from Cyprus; it
was known to them as _æs Cyprium_, and eventually _Cuprum_, whence we
obtain the chemical symbol Cu. What the Romans called _æs_ was found
also at Chalkis, in Eubœa, whence χαλκός, the Greek word for copper.
_Aurichalcum_, or golden copper—that is, brass—was well known to the
early workers in copper, and was made in Pliny’s time by heating
together copper, cadmia (calamine), and charcoal.
Bell metal was employed by the Assyrians, and bronze was cast by the
Egyptians for the manufacture of mirrors, vases, shields, etc., as far
back as 2000 B.C. Statuary bronze, largely used by the Romans, usually
contained more or less lead.
_Tin_, which was also known to the early Egyptians, would appear to
have been first obtained from the East Indies, and to have been known
under the Sanscrit name of _Kastîra_ (_Kâs_, to shine), whence we have
the Arabic word for tin, _Kàsdir_, and the Greek κασσίτερος, used by
Homer and Hesiod. Tin ores are found in Britain (Cornwall), and were
brought thence by the Phœnicians. The group of islands, including the
Scilly Islands and the larger island to the east (Britain), was known
to the Romans as the _Insulæ Cassiterides_.
Pliny states that the tin is found in grains in alluvial soil, from
which it is obtained by washing; but he gives no description of the
method of smelting. The Latin word for tin was _stannum_; it was also
known as _plumbum album_, in contradistinction to lead, which was
called _plumbum nigrum_. Tin was used by the Romans for covering the
inside of copper vessels, and was also occasionally employed in the
construction of mirrors.
_Lead_ was well known to the Egyptians. In Pliny’s time it was mainly
procured from Spain and from Britain (Derbyshire). Leaden pipes were
used by the Romans for the conveyance of water, and sheet lead was
employed by them for roofing purposes. The Romans were also aware of
alloys of lead and tin. _Argentarium_ was composed of equal parts of
lead and tin; _tertiarium_, used as a solder, consisted of two parts of
lead and one part of tin.
_Iron_, although now the most important of the common metals, was not
in general use until long after the discovery of gold, silver, and
copper. This was probably due to the fact that, although its ores
are relatively abundant and widely distributed, its extraction as a
metal demanded greater skill and more appliances than were possessed
by the earlier races. Metallic iron was, however, well known to the
Egyptians, who employed it in the manufacture of swords, knives,
axes, and stone-chisels, both as malleable iron and as steel. Steel
was also known to the Chinese as far back as 2220 B.C., and they were
acquainted with the methods of tempering it. The good quality of
Chinese steel caused it to be highly prized by Western nations. The
earliest people to smelt iron are supposed to have been the Chalybes, a
nation inhabiting the neighbourhood of the Black Sea; it is from them
that the ancient name for steel—_chalybs_—is derived, and also our word
“chalybeate.”
_Mercury_ has long been known, but there is no evidence that the
ancient Egyptians were aware of its existence, or it would probably
have been mentioned by Herodotus. It was familiar to Aristotle, and
its mode of manufacture from cinnabar is described by Theophrastus
(320 B.C.), who terms it “liquid silver.” Processes of amalgamation
were known to Pliny, who notes the readiness with which mercury
dissolves gold. Pliny appears to distinguish the native metal found
in Spain, which he terms _argentum vivum_ (quicksilver), from that
obtained by sublimation or distillation from cinnabar, which he calls
_hydrargyrum_, from which we get the chemical symbol for mercury Hg.
A considerable number of metallic compounds were known to the ancients,
and were employed by them as medicines and as pigments. The oxides
of copper, known as _flos æris_, and _scoria æris_, obtained by
heating copper bars to redness and exposing them to air, were used as
escharotics. Verdigris, or _ærugo_, was made by the same methods as
now. Blue vitriol, or _chalcantum_, is described by Pliny, who says
that the blue transparent crystals are formed on strings suspended in
its solution.
_Chrysocolla_, malachite, or copper carbonate, was used as a green
pigment. The blue κύανος of the Greeks, or _cœruleum_ of the Romans,
was obtained by fritting together alkali, sand, and oxide of copper.
_Botryitis_, _placitis_, _onychitis_, _ostracitis_, were varieties of
_cadmia_ or oxide of zinc, obtained by calcining calamine, and were
used in the treatment of ulcers, etc. _Molybdena_, which was the Latin
name for litharge, was employed externally as an astringent and in the
manufacture of plaster. The lead plaster employed by Roman surgeons was
practically identical in character and mode of preparation with that
in use to-day. _Cerussa_, or white lead, was made as now by exposing
sheets of lead to the fumes of vinegar. It was used in medicine,
as a pigment, and in the preparation of cosmetics. _Cerussa usta_
was probably red lead. Its present name of _minium_ was originally
applied to cinnabar, the red sulphide of mercury, which was frequently
adulterated with red lead.
_Cinnabar_, formerly obtained from Africa, and, by the Romans,
from Spain, was also used externally in medicine, and was a highly
prized pigment, whose value was known to the Chinese from very early
times. The black sulphide of antimony, the _stimmi_ and _stibium_ of
Dioscorides and Pliny, was employed by women in Asia, Greece, and
latterly in Western Europe, and is still so used in the East, for
blackening their eyelashes. Preparations of antimony were used in
medicine. _Realgar_, the scarlet sulphide of arsenic, the _sandarach_
of Aristotle, and the _arrenichon_ of Theophrastus, was employed as
a pigment, and also in medicine, both internally and externally. The
yellow sulphide of arsenic or _auri pigmentum_ (orpiment), was also
used for the same purposes.
A variety of yellow and red ochres, in addition to the pigments above
mentioned, were used by painters, such as _rubrica_, an iron ochre
of a dark red colour, and _sinopis_, or reddle, obtained from Egypt,
Lemnos, and the Balearic Isles. Oxides of manganese were used as brown
pigments. The white pigment, _paratonium_, was probably meerschaum.
_Melinum_ was a variety of chalk found in Samos. The ancients were well
acquainted with indigo and madder, and with the method of manufacturing
lakes, which was employed by Grecian artists.
The famous _purpurissum_ was chalk or clay stained by immersion in a
solution of Tyrian purple. _Atramentum_ was lamp-black: ivory-black
was used by Apelles, and was known as _elephantinum_. The ink of the
ancients consisted of lamp-black suspended in a solution of gum or
glue. The _atramentum indicum_, imported from the East, was identical
with China ink.
The ancients were well skilled in the art of dyeing, and even of
calico printing. The Tyrians produced their famous purple dye as far
back as 1500 B.C. It was obtained from shell-fish, mainly species of
Murex, inhabiting the Mediterranean. Tyrian purple has been shown to
be dibrom-indigo, and to have been produced by the action of air and
light upon the juices exuded from the shell-fish. The fine linen of the
Old Testament was probably cotton, for the production of which Egypt
was long celebrated. That the Egyptians were acquainted with the use of
mordants seems evident from the following passage from Pliny, quoted by
Thomson:—
There exists in Egypt a wonderful method of dyeing. The white
cloth is stained in various places, not with dye stuffs, but with
substances which have the property of absorbing colours; these
applications are not visible upon the cloth, but when they are
dipped into a hot caldron of the dye they are drawn out an instant
after dyed. The remarkable circumstance is that, though there be
only one dye in the vat, yet different colours appear upon the
cloth; nor can the colour be afterwards removed.
This passage accurately describes the process of madder dyeing on
cotton, whereby a variety of fast colours—reds, browns and purples—can
be obtained from the same vat by the employment of different mordants,
such as alumina, oxide of iron, or oxide of tin, etc.
Glass has been known from very early times. Representations of
glass-blowing were found on the monuments of Thebes and Beni Hassan,
and large quantities of glass were exported to Greece and Rome from
Egypt, mainly by Phœnicians. Aristophanes mentions it as _hyalos_, and
speaks of it as the beautiful transparent stone used for kindling fire.
The Egyptians made use of various metallic oxides in colouring glass.
The _hæmatinon_ of Pliny was a red glass coloured with cuprous oxide.
Cupric oxide was used to colour glass green; and ancient blue glass has
been found to contain cobalt. The costly _vasa murrhina_ of the Romans,
obtained from Egypt, probably consisted of fluorspar, identical with
the Blue John of the Derbyshire mines.
Stoneware has been made from time immemorial, and the Chinese have
manufactured porcelain from very remote periods. Bricks and tiles were
made by the Romans, and mortar and stucco were employed by the ancient
Egyptians.
Soap (_sapo_) is mentioned by Pliny, but its detergent properties were
apparently unknown to him. It appears to have been first made by the
Gauls, who prepared it from the ashes of the beech and the fat of
goats, and used it as a pomatum, as did the _jeunesse d’oreé_ of Rome.
Wood ashes, as well as natron, were, however, used by the ancients for
their cleansing properties.
Starch, acetic acid, sulphur, alumen or crude sulphate of alumina,
beeswax, camphor, bitumen, naphtha, asphalt, nitrum (carbonate of
soda), common salt, and lime, were all known to the Egyptians, and were
used by them for many of the purposes in which they are employed to-day.
It will be evident from this brief survey that the ancients possessed a
considerable acquaintance with many operations of technical chemistry;
but, although they must necessarily have accumulated a large amount
of knowledge, very little has come down to us concerning the mode
in which their processes were conducted, or as to the precautions
they employed to ensure uniform results. Their methods were probably
jealously guarded and handed down by successive members of the crafts
as precious secrets. The experienced masters of these crafts must
have met with many strange and perplexing phenomena in the course of
their operations, and a spirit of inquiry must thereby at times have
been awakened. But, under the conditions in which their industries
were prosecuted, the scientific spirit was not free to develop, for
science depends essentially upon free intercommunication of facts and
the spread of knowledge of natural phenomena. Moreover, the great
intellects of antiquity, for the most part, had little sympathy with
the operations of artisans, who, at least among the Greeks and Romans,
were, for the most part, slaves. Philosophers taught that industrial
work tended to lower the standard of thought. The priests, in most
ages, have looked more or less askance at attempts, on the part of the
laity, to inquire too closely into the causes of natural phenomena. The
investigation of nature in early times was impossible for religious
reasons. There was an outcry in Athens when the thunderbolts of Zeus
were ascribed to the collision of clouds. Anaxagoras, Diogenes of
Apollonia, Plato, Aristotle, Diagoras, and Protagoras were charged by
the priests with blasphemy and driven into exile. Prodikos, who deified
the natural forces, as did Empedokles the primal elements, was executed
for impiety. Sacerdotalism in Athens had no more sympathy with science
than had the Holy Congregation in Italy when it banned the writings of
Copernicus, Kepler, and Galileo, and sent Giordano Bruno to the stake.
The educated Greeks had no interest in observing or in explaining the
phenomena of technical processes. However prone they might be to
speculation, they had no inclination to experiment or to engage in the
patient accumulation of the knowledge of physical facts. “You Greeks,”
says Plato in one of his Dialogues, “are ever children, having no
knowledge of antiquity, nor antiquity of knowledge!” The influence of
a spurious Aristotelianism, which lasted through many centuries and
even beyond the time of Boyle, was wholly opposed to the true methods
of science, and it was only when philosophy had shaken itself free from
scholasticism that chemistry, as a science, was able to develop.