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HEROES OF SCIENCE.
Chemists
by
M. M. PATTISON MUIR, M.A., F.R.S.E.,
Fellow, and Praelector in Chemistry, of Gonville and Caius College,
Cambridge.
Published under the Direction of the Committee
of General Literature and Education Appointed by the
Society for Promoting Christian Knowledge.
London:
Society for Promoting Christian Knowledge,
Northumberland Avenue, Charing Cross;
43, Queen Victoria Street, E.C.;
26, St. George's Place, Hyde Park Corner, S.W.
Brighton: 135, North Street.
New York: E. & J. B. Young & Co.
1883.
"The discoveries of great men never leave us; they are
immortal; they contain those eternal truths which
survive the shock of empires, outlive the struggles of
rival creeds, and witness the decay of successive
religions."--BUCKLE.
"He who studies Nature has continually the exquisite
pleasure of discerning or half discerning and divining
laws; regularities glimmer through an appearance of
confusion, analogies between phenomena of a different
order suggest themselves and set the imagination in
motion; the mind is haunted with the sense of a vast
unity not yet discoverable or nameable. There is food
for contemplation which never runs short; you gaze at
an object which is always growing clearer, and yet
always, in the very act of growing clearer, presenting
new mysteries."--THE AUTHOR OF "ECCE HOMO."
"Je laenger ich lebe, desto mehr verlern' ich das
Gelernte, naemlich die Systeme."--JEAN PAUL RICHTER.
PREFACE.
I have endeavoured in this book to keep to the lines laid down for me by
the Publication Committee of the Society, viz. "to exhibit, by selected
biographies, the progress of chemistry from the beginning of the inductive
method until the present time." The progress of chemistry has been made the
central theme; around this I have tried to group short accounts of the
lives of those who have most assisted this progress by their labours.
This method of treatment, if properly conducted, exhibits the advances made
in science as intimately connected with the lives and characters of those
who studied it, and also impresses on the reader the continuity of the
progress of natural knowledge.
The lives of a few chemists have been written; of others there are,
however, only scanty notices to be found. The materials for this book have
been collected chiefly from the following works:--
Kopp's "Geschichte der Chemie."
Thomson's "History of Chemistry."
Ladenburg's "Entwickelungsgeschichte der Chemie."
Wurtz's "History of the Atomic Theory."
Watts's "Dictionary of Chemistry."
Whewell's "History of the Inductive Sciences."
Rodwell's "Birth of Chemistry;" "Inquiry into the
Hermetic Mystery and Alchemy" (London, 1850); "Popular
Treatises on Science written during the Middle Ages,"
edited for the Historical Society of Science by Thomas
Wright, M.A. (London, 1841); "Ripley Reviv'd; or, An
Exposition upon Sir George Ripley's Hermetico-Poetical
Works," by Eirenaeus Philalethes (London, 1678); "Tripus
Aureus, hoc est Tres Tractates Chymici Selectissimi"
(Frankfurt, 1618).
"Alchemy;" article in "Encyclopaedia Britannica."
Boyle's "Sceptical Chymist."
"Biographie Universelle;" for notices of Berzelius and
Lavoisier.
"English Cyclopaedia;" for notices of Black, Berzelius
and Lavoisier.
Black's "Lectures," with Memoir: edited by Dr.
Robinson.
Priestley's "Memoirs:" written partly by himself.
Priestley's works on "Air," etc.
Lavoisier's "Oeuvres."
Dalton's "Life," by Dr. Henry; "Life," by Dr. R. Angus
Smith; "New System of Chemical Philosophy."
Davy's "Collected Works;" with Life, by his brother;
"Life," by Dr. Paris.
Berzelius's "Lehrbuch," and various dissertations.
Woehler's "Jugenderinnerungen eines Chemikers."
Graham's "Collected Memoirs."
Sketch of Graham's life, in Chemical Society's Journal.
"Life-Work of Liebig," by A. W. Hofmann.
"Dumas," by A. W. Hofmann.
Various dissertations by Liebig and Dumas in _Annalen_,
and elsewhere.
My warmest thanks are due to my friend, Mr. Francis Rye, for the great
assistance he has given me in correcting the proof-sheets.
M. M. PATTISON MUIR.
CAMBRIDGE, _April, 1883_.
CONTENTS.
PAGE
INTRODUCTORY 1
CHAPTER I.
ALCHEMY: AND THE DAWN OF CHEMISTRY.
Beginnings of natural knowledge--Chemistry in the
Middle Ages--Alchemy--The phlogistic theory 5
CHAPTER II.
ESTABLISHMENT OF CHEMISTRY AS A SCIENCE--PERIOD OF BLACK, PRIESTLEY AND
LAVOISIER.
Introduction of accurate measurements into
chemistry--Black's researches on alkalis and on fixed
air--His conception of heat--Priestley's experiments on
airs--His discovery of oxygen--Lavoisier, the founder
of the science of chemistry--He clearly establishes a
connection between composition and properties of bodies 30
CHAPTER III.
ESTABLISHMENT OF GENERAL PRINCIPLES OF CHEMICAL SCIENCE--PERIOD OF DALTON.
Dalton's training in physical science--He revives and
renders quantitative the atomic theory--The term "atom"
is applied by him to elements and compounds alike--His
rules for chemical synthesis 106
CHAPTER IV.
ESTABLISHMENT OF GENERAL PRINCIPLES OF CHEMICAL SCIENCE
(_continued_)--PERIOD OF DAVY AND BERZELIUS.
Electro-chemistry--The dualistic theory developed by
Berzelius--Davy's work on acids, alkalis, and salts--He
proves chlorine to be an element--His discovery of the
safety-lamp 155
CHAPTER V.
THE WORK OF GRAHAM.
Graham traces the movements of molecules--He
distinguishes between colloids and
cystalloids--Dialysis 232
CHAPTER VI.
RISE AND PROGRESS OF ORGANIC CHEMISTRY--PERIOD OF LIEBIG AND DUMAS.
The barrier between inorganic and organic chemistry
begins to be broken down--Woehler prepares urea--Dumas
opposes the dualistic system of Berzelius--Liebig's
conception of compound radicles--His work in animal and
agricultural chemistry 252
CHAPTER VII.
MODERN CHEMISTRY.
The relations between composition and properties of
bodies are developed and rendered more
definite--Physical methods are more largely made use of
in chemistry--Spectroscopic analysis 294
CHAPTER VIII.
SUMMARY AND CONCLUSION 316
HEROES OF SCIENCE.
INTRODUCTORY.
As we trace the development of any branch of natural knowledge we find that
there has been a gradual progress from vague and fanciful to accurate and
definite views of Nature. We find that as man's conceptions of natural
phenomena become more accurate they also for a time become more limited,
but that this limitation is necessary in order that facts may be correctly
classified, and so there may be laid the basis for generalizations which,
being definite, shall also be capable of expansion.
At first Nature is strange; she is full of wonderful and fearful
appearances. Man is overwhelmed by the sudden and apparently irregular
outbreaks of storms, by the capricious freaks of thunder and lightning, by
the awful and unannounced devastations of the volcano or the earthquake; he
believes himself to be surrounded by an invisible array of beings more
powerful than himself, but, like himself, changeable in their moods and
easily provoked to anger. After a time he begins to find that it is
possible to trace points of connection between some of the appearances
which had so overpowered or perplexed him.
The huntsman observes that certain kinds of plants always grow where the
game which he pursues is chiefly to be found; from the appearance of the
sky at morning and evening the fisherman is able to tell whether there will
follow weather suitable for him to set out in his fishing-boat; the tiller
of the ground begins to feel sure that if he sow the seed in the well-dug
soil and water it in proper seasons he will certainly reap the harvest in
due time. And thus man comes to believe that natural events follow each
other in a fixed order; there arises a conscious reference on his part of
certain effects to certain definite causes. Accurate knowledge has begun.
As knowledge of natural appearances advances there comes a time when men
devote themselves chiefly to a careful study of some one class of facts;
they try to consider that part of Nature with which they are mostly
concerned as separate from all other parts of Nature. Thus the various
branches of natural knowledge begin to have each a distinct existence.
These branches get more and more subdivided, each division is more
accurately studied, and so a great number of facts is accumulated in many
classes. Then we usually find that a master mind arises, who shows the
connection which exists between the different parts of each division of
natural knowledge, who takes a wide, far-reaching view of the whole range
of the province of knowledge which he studies, and who, at the same time,
is able to hold in his vision all the important details of each branch of
which that province is composed.
And thus we again get wide views of Nature. But these are very different
from the vague, dim and hesitating notions in which natural knowledge had
its beginnings. In this later time men see that Nature is both simple and
complex; that she is more wonderful than their fathers dreamed, but that
through all the complexity there runs a definite purpose; that the
apparently separate facts are bound together by definite laws, and that to
discover this purpose and these laws is possible for man.
As we trace this progress in the various branches of natural knowledge we
are struck with the fact that each important advance is generally
accomplished by one or two leading men; we find that it becomes possible to
group the history of each period round a few central figures; and we also
learn that the character of the work done by each of these men of note is
dependent on the nature and training of the individual man.
It will be my endeavour in the following pages to give an account of the
advance of chemical science, grouping the facts in each stage of progress
round the figures of one or two men who were prominent in that period.
For the purposes of this book it will be necessary that I should sketch
only the most important periods in the story of chemical progress, and that
in each of these I should fill in the prominent points alone.
I shall therefore select three periods in the progress of this science, and
try to give an account of the main work done in each of these. And the
periods will be:--
I. The period wherein, chiefly by the work of Black, Priestley and
Lavoisier, the aim of chemical science was defined and the essential
characters of the phenomena to be studied were clearly stated.
II. The period during which, chiefly by the labours of Dalton, Berzelius
and Davy, the great central propositions of the science were laid down and
were developed into a definite theory. As belonging in great extent to this
period, although chronologically later, I shall also consider the work of
Graham.
III. The period when, chiefly owing to advances made in organic chemistry,
broader and more far-reaching systems of classification were introduced,
and the propositions laid down in the preceding period were modified and
strengthened. The workers in this period were very numerous; I shall
chiefly consider these two--Liebig and Dumas.
I shall conclude with a brief sketch of some of the important advances of
chemical science in more recent times, and a summary of the characteristics
of each of the three periods.
CHAPTER I.
ALCHEMY: AND THE DAWN OF CHEMISTRY.
Early chemistry was not a science. The ancient chemists dealt chiefly with
what we should now call chemical manufactures; they made glass, cleaned
leather, dyed cloth purple and other colours, extracted metals from their
ores, and made alloys of metals. No well-founded explanations of these
processes could be expected either from men who simply used the recipes of
their predecessors, or from philosophers who studied natural science, not
by the help of accurate experiments, but by the unaided light of their own
minds.
At somewhat later times chemistry assumed a very important place in the
general schemes propounded by philosophers.
Change is vividly impressed on all man's surroundings: the endeavour to
find some resting-place amidst the chaos of circumstances, some unchanging
substance beneath the ever-changing appearances of things, has always held
a prominent place with those who study the phenomena of the world which
surrounds them. In the third and fourth centuries of our era much attention
was given to the art which professed to explain the changes of Nature.
Religion, philosophy, and what we should now call natural science, were at
that time closely intermingled; the scheme of things which then, and for
several centuries after that time, exerted a powerful influence over the
minds of many thinkers was largely based on the conception of a fundamental
unity underlying and regulating the observed dissimilarities of the
universe.
Thus, in the _Emerald Table of Hermes_, which was held in much repute in
the Middle Ages, we read--
"True, without error, certain and most true: that which is above is as that
which is below, and that which is below is as that which is above, for
performing the miracles of the _One Thing_; and as all things were from
one, by the mediation of one, so all things arose from this one thing by
adaptation: the father of it is the Sun, the mother of it is the Moon, the
wind carried it in its belly, the nurse of it is the Earth. This is the
father of all perfection, the consummation of the whole world."
And again, in a later writing we have laid down the basis of the art of
alchemy in the proposition that "there abides in nature a certain pure
matter, which, being discovered and brought by art to perfection, converts
to itself proportionally all imperfect bodies that it touches."
To discover this fundamental principle, this _One Thing_, became the object
of all research. Earth and the heavens were supposed to be bound together
by the all-pervading presence of the One Thing; he who should attain to a
knowledge of this precious essence would possess all wisdom. To the vision
of those who pursued the quest for the One Thing the whole universe was
filled by one ever-working spirit, concealed now by this, now by that veil
of sense, ever escaping identification in any concrete form, yet certainly
capable of being apprehended by the diligent searcher.
Analogy was the chief guide in this search. If it were granted that all
natural appearances were manifestations of the activity of one essential
principle, then the vaguest and most far-fetched analogies between the
phenomena of nature might, if properly followed up, lead to the
apprehension of this hidden but everywhere present essence.
The history of alchemy teaches, in the most striking manner, the dangers
which beset this method of pursuing the study of Nature; this history
teaches us that analogies, unless founded on carefully and accurately
determined facts, are generally utterly misleading in natural science.
Let us consider the nature of the experimental evidence which an alchemist
of the fourth or fifth century could produce in favour of his statement
that transmutation of one kind of matter into another is of constant
occurrence in Nature.
The alchemist heated a quantity of water in an open glass vessel; the water
slowly disappeared, and when it was all gone there remained in the vessel a
small quantity of a white earthy solid substance. What could this
experiment teach save that water was changed into earth and air? The
alchemist then plunged a piece of red-hot iron into water placed under a
bell-shaped glass vessel; some of the water seemed to be changed into air,
and a candle, when brought into the bell, caused the air therein to take
fire. Therefore, concluded the experimenter, water is proved to be
changeable into fire.
A piece of lead was then strongly heated in the air; it lost its lustre and
became changed into a reddish-white powder, very unlike lead in its
properties; this powder was then heated in a convenient vessel with a
little wheat, whereupon the lead was again produced. Therefore, said the
alchemist, lead is destroyed by fire, but it can be reproduced from its
ashes by the help of heat and a few grains of corn.
The experimenter would now proceed to heat a quantity of a mineral
containing lead in an open vessel made of pulverized bones; the lead slowly
disappeared, and at the close of the experiment a button of silver
remained. Might he not triumphantly assert that he had transmuted lead into
silver?
In order that the doctrine of the transmutation of metals might rest on yet
surer evidence, the alchemist placed a piece of copper in spirits of nitre
(nitric acid); the metal disappeared; into the green liquid thus produced
he then placed a piece of iron; the copper again made its appearance, while
the iron was removed. He might now well say that if lead was thus
demonstrably changed into silver, and copper into iron, it was, to say the
least, extremely probable that any metal might be changed into any other
provided the proper means for producing the change could be discovered.
But the experimental alchemist had a yet stranger transmutation wherewith
to convince the most sceptical. He poured mercury in a fine stream on to
melted sulphur; at once the mercury and the sulphur disappeared, and in
their place was found a solid substance black as the raven's wing. He then
heated this black substance in a closed vessel, when it also disappeared,
and in its place there was found, deposited on the cooler part of the
vessel, a brilliantly red-coloured solid. This experiment taught lessons
alike to the alchemist, the philosopher, and the moralist of these times.
The alchemist learned that to change one kind of matter into another was an
easy task: the philosopher learned that the prevalence of change or
transmutation is one of the laws of Nature: and the moralist learned that
evil is not wholly evil, but contains also some germs of good; for was not
the raven-black substance emblematical of the evil, and the red-coloured
matter of the good principle of things?[1]
On such experimental evidence as this the building of alchemy was reared. A
close relationship was believed to prevail through the whole phenomena of
Nature. What more natural then than to regard the changes which occur among
the forms of matter on this earth as intimately connected with the changes
which occur among the heavenly bodies?
Man has ever been overawed by the majesty of the stars; yet he has not
failed to notice that the movements of these bodies are apparently
capricious. The moon has always been to him a type of mutability; only in
the sun has he seemed to find a settled resting-point. Now, when we
remember that in the alchemical scheme of things the material earth and
material heavens, the intellectual, the moral, and the spiritual world were
regarded as one great whole, the parts of which were continuously acting
and reacting on each other, we cannot wonder that the alchemist should
regard special phenomena which he observed in his laboratory, or special
forms of matter which he examined, as being more directly than other
phenomena or other forms of matter, under the influence of the heavenly
bodies. This connection became gradually more apparent to the student of
alchemy, until at last it was fixed in the language and the symbols which
he employed.
Thus the sun (Sol) was represented by a circle, which likewise became the
symbol for gold, as being the most perfect metal. The moon (Luna) was ever
changing; she was represented by a half-circle, which also symbolized the
pale metal silver.
Copper and iron were regarded as belonging to the same class of metals as
gold, but their less perfect nature was denoted by the sign + or ^. Tin and
lead belonged to the lunar class, but like copper they were supposed to be
imperfect metals. Mercury was at once solar and lunar in its properties.
These suppositions were summed up in such alchemical symbols as are
represented below--
[Illustration: Sol. Gold.]
[Illustration: Luna. Silver.]
[Illustration: Venus. Copper.]
[Illustration: Mars. Iron.]
[Illustration: Jupiter. Tin.]
[Illustration: Saturn. Lead.]
[Illustration: Mercury. Quicksilver.]
Many of the alchemical names remain to the present time; thus in pharmacy
the name "lunar caustic" is applied to silver nitrate, and the symptoms
indicative of lead-poisoning are grouped together under the designation of
"saturnine cholic."
But as the times advanced the older and nobler conception of alchemy became
degraded.
If it be true, the later alchemists urged, that all things suffer change,
but that a changeless essence or principle underlies all changing things,
and that the presence of more or less of this essence confers on each form
of matter its special properties, it follows that he who can possess
himself of this principle will be able to transmute any metal into any
other; he will be able to change any metal into gold.
Now, as the possession of gold has always carried with it the means of
living luxuriously, it is easy to understand how, when this practical
aspect of alchemy had taken firm root in men's minds, the pursuit of the
art became for all, except a few lofty and noble spirits, synonymous with
the pursuit of wealth. So that we shall not, I think, much err if we
describe the chemistry of the later Middle Ages as an effort to accumulate
facts on which might be founded the art of making gold. In one respect this
was an advance. In the early days of alchemy there had been too much
trusting to the mental powers for the manufacture of natural facts:
chemists now actually worked in laboratories; and very hard did many of
these alchemists work.
Paracelsus says of the alchemists, "They are not given to idleness, nor go
in a proud habit, or plush and velvet garments, often showing their rings
upon their fingers, or wearing swords with silver hilts by their sides, or
fine and gay gloves upon their hands; but diligently follow their labours,
sweating whole days and nights by their furnaces. They do not spend their
time abroad for recreation, but take delight in their laboratory. They put
their fingers amongst coals, into clay and filth, not into gold rings. They
are sooty and black like smiths and miners, and do not pride themselves
upon clean and beautiful faces." By thus "taking delight in their
laboratories" the later alchemists gathered together many facts; but their
work centred round one idea, viz. that metals might all be changed into
gold, and this idea was the result rather of intellectual guessing than of
reasoning on established facts of Nature.
One of the most famous alchemists of the Middle Ages was born at
Einsiedeln, in Switzerland, in 1493. His name, when paraphrased into Greek,
became Paracelsus. This man, some of whose remarks have just been quoted,
acquired great fame as a medical practitioner, and also as a lecturer on
medicine: he travelled throughout the greater part of Europe, and is
supposed to have been taught the use of several new medicines by the
Arabian physicians whom he met in Spain. With an over-weening sense of his
own powers, with an ardent and intemperate disposition, revolting against
all authority in medicine or science, Paracelsus yet did a good work in
calling men to the study of Nature as the only means whereby natural
science could be advanced.
"Alchemy has but one aim and object," Paracelsus taught: "to extract the
quintessence of things, and to prepare arcana and elixirs which may serve
to restore to man the health and soundness he has lost." He taught that the
visible universe is but an outer shell or covering, that there is a spirit
ever at work underneath this veil of phenomena; but that all is not active:
"to separate the active function (the spirit) of this outside shell from
the passive" was, he said, the proper province of alchemy.
Paracelsus strongly insisted on the importance of the changes which occur
when a substance burns, and in doing this he prepared the way for Stahl and
the phlogistic chemists.
However we may admire the general conceptions underlying the work of the
earlier alchemists, we must admit that the method of study which they
adopted could lead to very few results of lasting value; and I think we may
add that, however humble the speculations of these older thinkers might
appear, this humility was for the most part only apparent.
These men were encompassed (as we are) by unexplained appearances: they
were every moment reminded that man is not "the measure of all things;"
and by not peering too anxiously into the mysteries around them, by drawing
vague conclusions from partially examined appearances, they seemed at once
to admit their own powerlessness and the greatness of Nature. But I think
we shall find, as we proceed with our story, that this is not the true kind
of reverence, and that he is the really humble student of Nature who
refuses to overlook any fact, however small, because he feels the
tremendous significance of every part of the world of wonders which it is
his business and his happiness to explore.
As examples of the kind of explanation given by alchemists of those aspects
of Nature which they professed to study, I give two quotations from
translations of the writings of Basil Valentine and Paracelsus, who
flourished in the first half of the fifteenth and sixteenth centuries
respectively.
"Think most diligently about this; often bear in mind, observe and
comprehend that all minerals and metals together, in the same time, and
after the same fashion, and of one and the same principal matter, are
produced and generated. That matter is no other than a mere vapour, which
is extracted from the elementary earth by the superior stars, or by a
sidereal distillation of the macrocosm; which sidereal hot infusion, with
an airy sulphureous property, descending upon inferiors, so acts and
operates as that there is implanted, spiritually and invisibly, a certain
power and virtue in those metals and minerals; which fume, moreover,
resolves in the earth into a certain water wherefrom all metals are
thenceforth generated and ripened to their perfection, and thence proceeds
this or that metal or mineral, according as one of the three principles
acquires dominion and they have much or little of sulphur and salt, or an
unequal mixture of these; whence some metals are fixed, that is, constant
or stable; and some are volatile and easily changeable, as is seen in gold,
silver, copper, iron, tin and lead."
"The life of metals is a secret fatness; of salts, the spirit of aqua
fortis; of pearls, their splendour; of marcasites and antimony, a tingeing
metalline spirit; of arsenics, a mineral and coagulated poison. The life of
all men is nothing else but an astral balsam, a balsamic impression, and a
celestial invisible fire, an included air, and a tingeing spirit of salt. I
cannot name it more plainly, although it is set out by many names."
When the alchemists gave directions for making the stone which was to turn
all it touched into gold, they couched them in such strange and symbolical
language as this: "After our serpent has been bound by her chain,
penetrated with the blood of our green dragon, and driven nine or ten times
through the combustible fire into the elementary air, if you do not find
her to be exceeding furious and extremely penetrating, it is a sign that
you do not hit our subject, the notion of the homogenea, or their
proportion; if this furious serpent does not come over in a cloud and turn
into our virgin milk, or argentine water, not corrosive at all and yet
insensibly and invisibly devouring everything that comes near it, it is
plainly to be seen that you err in the notion of our universal menstruum."
Or, again, what could any reasonable man make of this? "In the green lion's
bed the sun and moon are born; they are married and beget a king. The king
feeds on the lion's blood, which is the king's father and mother, who are
at the same time his brother and sister. I fear I betray the secret, which
I promised my master to conceal in dark speech from any one who knows not
how to rule the philosopher's fire."
Concerning the same lion, another learned author says that "though called a
lion, it is not an animal substance, but for its transcendant force, and
the rawness of its origin, it is called the green lion." But he adds in a
moment of confidence: "This horrid beast has so many names, that unless God
direct the searcher it is impossible to distinguish him."
And once more. "Take our two serpents, which are to be found everywhere on
the face of the earth: tie them in a love-knot and shut them up in the
Arabian _caraha_. This is the first labour; but the next is more difficult.
Thou must encamp against them with the fire of nature, and be sure thou
dost bring thy line round about. Circle them in and stop all avenues that
they find no relief. Continue this siege patiently, and they turn into an
ugly venomous black toad, which will be transformed to a horrible devouring
dragon, creeping and weltering in the bottom of her cave without wings.
Touch her not by any means, for there is not on earth such a vehement
transcending poison. As thou hast begun so proceed, and this dragon will
turn into a swan. Henceforth I will show thee how to fortify thy fire till
the phoenix appear: it is a red bird of a most deep colour, with a
shining fiery hue. Feed this bird with the fire of his father and the ether
of his mother: for the first is meat and the second is drink, and without
this last he attains not to his full glory. Be sure to understand this
secret," etc., etc.
The alchemists spoke of twelve gates through which he who would attain to
the palace of true art must pass: these twelve gates were to be unlocked by
twelve keys, descriptions of which, couched in strange and symbolical
language, were given in alchemical treatises. Thus in "Ripley reviv'd"[2]
we read that Canon Ripley, of Bridlington, who lived in the time of Edward
IV., sang thus of the first gate, which was "Calcination:"--
"The battle's fought, the conquest won,
The Lyon dead reviv'd;
The eagle's dead which did him slay,
And both of sense depriv'd.
The showers cease, the dews which fell
For six weeks do not rise;
The ugly toad that did so swell
With swelling bursts and dies."
And of the third gate, or "Conjunction," we find the Canon saying--
"He was a king, yet dead as dead could be;
His sister a queen,
Who when her brother she did breathless see,
The like was never seen,
She cryes
Until her eyes
With over-weeping were waxed dim--
So long till her tears
Reach'd up to her ears:
The queen sunk, but the king did swim."
In some books these gates and keys are symbolically represented in
drawings, _e.g._ in a pamphlet by Paracelsus, called "Tripus Aureus, hoc
est Tres Tractates chymici selectissimi." (Frankfurt, 1618.)
It is evident that a method of studying Nature which resulted in such dim
and hazy explanations as these was eminently fitted to produce many who
pretended to possess secrets by the use of which they could bring about
startling results beyond the power of ordinary men; and, at the same time,
the almost universal acceptance of such statements as those I have quoted
implied the existence in men generally of a wondrous readiness to believe
anything and everything. Granted that a man by "sweating whole days and
nights by his furnaces" can acquire knowledge which gives him great power
over his fellows, it necessarily follows that many will be found ready to
undergo these days and nights of toil. And when we find that this supposed
knowledge is hidden under a mask of strange and mystical signs and
language, we may confidently assert that there will be many who learn to
repeat these strange terms and use these mystical signs without attempting
to penetrate to the truths which lie behind--without, indeed, believing
that the mystical machinery which they use has any real meaning at all.
We find, as a matter of fact, that the age of the alchemists produced many
deceivers, who, by mumbling incantations and performing a few tricks, which
any common conjuror would now despise, were able to make crowds of men
believe that they possessed a supernatural power to control natural
actions, and, under this belief, to make them part with their money and
their substance.
One respectable physician of the Hague, who entertained a peripatetic
alchemist, complains that the man entered his "best-furnished room without
wiping his shoes, although they were full of snow and dirt." However, the
physician was rewarded, as the stranger gave him, "out of his philosophical
commiseration, as much as a turnip seed in size" of the much-wished-for
stone of wisdom.
That the alchemist of popular belief was a man who used a jargon of strange
and high-sounding words, that he might the better deceive those whom he
pretended to help, is evident from the literature of the sixteenth and
seventeenth centuries.
In the play of the "Alchymist" Ben Jonson draws the character of Subtle as
that of a complete scoundrel, whose aim is to get money from the pockets of
those who are stupid enough to trust him, and who never hesitates to use
the basest means for this end. From the speeches of Subtle we may learn the
kind of jargon employed by the men who pretended that they could cure
diseases and change all baser metals into gold.
"_Subtle._ Name the vexations and the martyrizations of metals in
the work.
_Face._ Sir, putrefaction,
Solution, ablution, sublimation,
Cohobation, calcination, ceration, and
Fixation.
_Sub._ And when comes vivification?
_Face._ After mortification.
_Sub._ What's cohobation?
_Face._ 'Tis the pouring on
Your aqua regis, and then drawing him off,
To the trine circle of the seven spheres.
* * * * *
_Sub._ And what's your mercury?
_Face._ A very fugitive; he will be gone, sir.
_Sub._ How know you him?
_Pace._ By his viscosity,
His oleosity, and his suscitability."
Even in the fourteenth century, Chaucer (in the "Canon's Yeoman's Tale")
depicts the alchemist as a mere cunning knave. A priest is prevailed on to
give the alchemist money, and is told that he will be shown the change of
base metal into gold. The alchemist busies himself with preparations, and
sends the priest to fetch coals.
"And whil he besy was, this feendly wrecche,
This false chanoun (the foule feende him fecche)
Out of his bosom took a bechen cole
In which ful subtilly was maad an hole,
And therein put was of silver lymayle
An unce, and stopped was withoute fayle
The hole with wex, to keep the lymayle in.
And understondith, that this false gyn
Was not maad there, but it was maad before."
This "false gyn" having been put in the crucible and burned with the rest
of the ingredients, duly let out its "silver lymayle" (filings), which
appeared in the shape of a small button of silver, and so accomplished the
"false chanoun's" end of deceiving his victim.
The alchemists accumulated many facts: they gained not a little knowledge
concerning the appearances of Nature, but they were dominated by a single
idea. Living in the midst of an extremely complex order of things,
surrounded by a strange and apparently capricious succession of phenomena,
they were convinced that the human intelligence, directed and aided by the
teachings of the Church, would guide them through the labyrinth. And so
they entered on the study of Nature with preconceived notions and foregone
conclusions: enthusiastic and determined to know although many of them
were, they nevertheless failed because they refused to tread the only path
which leads to true advances in natural science--the path of unprejudiced
accurate experiment, and of careful reasoning on experimentally determined
facts.
And even when they had become convinced that their aims were visionary,
they could not break free from the vicious system which bound them.
"... I am broken and trained
To my old habits: they are part of me.
I know, and none so well, my darling ends
Are proved impossible: no less, no less,
Even now what humours me, fond fool, as when
Their faint ghosts sit with me and flatter me,
And send me back content to my dull round."[3]
One of the most commonly occurring and most noticeable changes in the
properties of matter is that which proceeds when a piece of wood, or a
candle, or a quantity of oil burns. The solid wood, or candle, or the
liquid oil slowly disappears, and this disappearance is attended with the
visible formation of flame. Even the heavy fixed metals, tin or lead, may
be caused to burn; light is produced, a part of the metal seems to
disappear, and a white (or reddish) solid, very different from the original
metal, remains. The process of burning presents all those peculiarities
which are fitted to strike an observer of the changes of Nature; that is,
which are fitted to strike a chemist--for chemistry has always been
recognized as having for its object to explain the changes which matter
undergoes. The chemists of the seventeenth and eighteenth centuries were
chiefly occupied in trying to explain this process of burning or
combustion.
Van Helmont (1577-1644), who was a physician and chemist of Brussels,
clearly distinguished between common air and other "airs" or gases produced
in different ways. Robert Hooke (1635-1703), one of the original Fellows of
the Royal Society, in the "Micographia, or Philosophical Description of
Minute Bodies," published in 1665, concluded from the results of numerous
experiments that there exists in common air a peculiar kind of gas, similar
to, or perhaps identical with the gas or air which is got by heating
saltpetre; and he further supposed that when a solid burns, it is dissolved
by (or we should now say, it is converted into a gas by combining with)
this peculiar constituent of the air.
John Mayow (1645-1679), a physician of Oxford, experimented on the basis of
facts established by Hooke. He showed that when a substance, _e.g._ a
candle, burns in air, the volume of air is thereby lessened. To that
portion of the air which had _dissolved_ the burned substance he gave the
name of _nitre-air_, and he argued that this air exists in condensed form
in nitre, because sulphur burns when heated with nitre in absence of common
air. Mayow added the most important fact--a fact which was forgotten by
many later experimenters--that the solid substance obtained by burning a
metal in air weighs more than the metal itself did before burning. He
explained this increase in weight by saying that the burning metal absorbs
particles of "nitre-air" from the atmosphere. Thus Hooke and Mayow had
really established the fact that common air consists of more than one
definite kind of matter--in other words, that common air is not an element;
but until recent times the term "element" or "elementary principle" was
used without any definite meaning. When we say that the ancients and the
alchemists recognized four elements--earth, air, fire, and water--we do not
attach to the word "element" the same definite meaning as when we now say,
"Iron is an element."
From earth, air, fire and water other substances were obtained; or it might
be possible to resolve other substances into one or more of these four. But
even to such a word as "substance" or "matter" no very definite meaning
could be attached. Although, therefore, the facts set forth by Hooke and
Mayow might now justify the assertion that air is not an element, they did
not, in the year 1670, necessarily convey this meaning to men's minds. The
distinction between element and compound was much more clearly laid down by
the Hon. Robert Boyle (1627-1691), whose chemical work was wonderfully
accurate and thorough, and whose writings are characterized by acute
scientific reasoning. We shall again return to these terms "element" and
"compound."
But the visible and striking phenomenon in most processes of burning is the
production of light and sometimes of flame. The importance of the fact
that the burned substance (when a solid) weighs more than the unburned
substance was overshadowed by the apparent importance of the outward part
of the process, which could scarcely be passed over by any observer. There
appears to be an outrush of _something_ from the burning substance. There
_is_ an outrush of something, said Becher and Stahl, and this something is
the "principle of fire." The principle of fire, they said, is of a very
subtle nature; its particles, which are always in very rapid motion, can
penetrate any substance, however dense. When metals burn--the argument
continued--they lose this principle of fire; when the burned metal--or
_calx_ as it was usually called--is heated with charcoal it regains this
"principle," and so the metal is re-formed from the calx.
Thus arose the famous theory of _phlogiston_ (from Greek, = "burned"),
which served as a central nucleus round which all chemical facts were
grouped for nearly a hundred years.
John Joachim Becher was born at Speyer in 1635, and died in 1682; in his
chemical works, the most important of which is the "Physica Subterranea,"
he retained the alchemical notion that the metals are composed of three
"principles"--the nitrifiable, the combustible, and the mercurial--and
taught that during calcination the combustible and mercurial principles are
expelled, while the nitrifiable remains in the calx.
George Ernest Stahl--born at Anspach in 1660, and died at Berlin in
1734--had regard chiefly to the principles which escape during the
calcination of metals, and simplifying, and at the same rendering more
definite the idea of Becher, he conceived and enunciated the theory of
phlogiston.
But if _something_ (name it "phlogiston" or call it by any other name you
please) is lost by a metal when the metal is burned, how is it that the
loss of this thing is attended with an increase in the weight of the matter
which loses it? Either the theory of phlogiston must be abandoned, or the
properties of the _thing_ called phlogiston must be very different from
those of any known kind of matter.
Stahl replied, phlogiston is a "principle of levity;" the presence of
phlogiston in a substance causes that substance to weigh less than it did
before it received this phlogiston.
In criticizing this strange statement, we must remember that in the middle
of the seventeenth century philosophers in general were not firmly
convinced of the truth that the essential character of matter is that it
possesses weight, nor of the truth that it is impossible to destroy or to
create any quantity of matter however small. It was not until the
experimental work of Lavoisier became generally known that chemists were
convinced of these truths. Nevertheless, the opponents of the Stahlian
doctrine were justified in asking for further explanations--in demanding
that some other facts analogous to this supposed fact, viz. that a
substance can weigh less than nothing, should be experimentally
established.
The phlogistic theory however maintained its ground; we shall find that it
had a distinct element of truth in it, but we shall also find that it did
harm to scientific advance. This theory was a wide and sweeping
generalization from a few facts; it certainly gave a central idea around
which some facts might be grouped, and it was not very difficult, by
slightly cutting down here and slightly adding there, to bring many new
discoveries within the general theory.
We now know that in order to explain the process of combustion much more
accurate knowledge was required than the chemists of the seventeenth
century possessed; but we ought to be thankful to these chemists, and
notably to Stahl, that they did not hesitate to found a generalization on
the knowledge they had. Almost everything propounded in natural science has
been modified as man's knowledge of nature has become wider and more
accurate; but it is because the scientific student of nature uses the
generalizations of to-day as stepping-stones to the better theories of
to-morrow, that science grows "from more to more."
Looking at the state of chemistry about the middle of the eighteenth
century, we find that the experiments, and especially the measurements, of
Hooke and Mayow had laid a firm basis of fact concerning the process of
combustion, but that the phlogistic theory, which appeared to contradict
these facts, was supreme; that the existence of airs, or gases, different
from common air was established, but that the properties of these airs were
very slightly and very inaccurately known; that Boyle had distinguished
element from compound and had given definite meanings to these terms, but
that nevertheless the older and vaguer expression, "elementary principle,"
was generally used; and lastly, that very few measurements of the masses of
the different kinds of matter taking part in chemical changes had yet been
made.
FOOTNOTES:
[1] I have borrowed these illustrations of the alchemical, experimental
method from M. Hoefer's "Histoire de la Chimie," quoted in the
"Encyclopaedia Brittanica," art. "Alchemy."
[2] "Ripley reviv'd: or an exposition upon Sir George Ripley's
Hermetico-poetical works," by Eirenaeus Philalethes. London, 1678.
[3] Browning's "Paracelsus."