CHEMISTRY OF THE ARABIANS.
Hitherto I have spoken of Alchymy, or of the chemical manufactures
of the ancients. The people to whom scientific chemistry owes its
origin are the Arabians. Not that they prosecuted scientific chemistry
themselves; but they were the first persons who attempted to form
chemical medicines. This they did by mixing various bodies with each
other, and applying heat to the mixture in various ways. This led to
the discovery of some of the mineral acids. These they applied to
the metals, &c., and ascertained the effects produced upon that most
important class of bodies. Thus the Arabians began those researches
which led gradually to the formation of scientific chemistry. We must
therefore endeavour to ascertain the chemical facts for which we are
indebted to the Arabians.
When Mahomet first delivered his dogmas to his countrymen they were not
altogether barbarous. Possessed of a copious and expressive language,
and inhabiting a burning climate, their imaginations were lively and
their passions violent. Poetry and fiction were cultivated by them
with ardour, and with considerable success. But science and inductive
philosophy, had made little or no progress among them. The fatalism
introduced by Mahomet, and the blind enthusiasm which he inculcated,
rendered them furious bigots and determined enemies to every kind of
intellectual improvement. The rapidity with which they overran Asia,
Africa, and even a portion of Europe, is universally known. At that
period the western world, was sunk into extreme barbarism, and the
Greeks, with whom the remains of civilization still lingered, were
sadly degenerated from those sages who graced the classic ages. Bent
to the earth under the most grinding but turbulent despotism that
ever disgraced mankind, and having their understandings sealed up by
the most subtle and absurd, and uncompromising superstition, all the
energy of mind, all the powers of invention, all the industry and
talent, which distinguished their ancestors, had completely forsaken
them. Their writers aimed at nothing new or great, and were satisfied
with repeating the scientific facts determined by their ancestors. The
lamp of science fluttered in its socket, and was on the eve of being
extinguished.
Nothing good or great could be expected from such a state of society.
It was, therefore, wisely determined by Providence that the Mussulman
conquerors, should overrun the earth, sweep out those miserable
governors, and free the wretched inhabitants from the trammels of
despotism and superstition. As a despotism not less severe, and a
superstition still more gloomy and uncompromising, was substituted in
their place, it may seem at first sight, that the conquests of the
Mahometans brought things into a worse state than they found them. But
the listless inactivity, the almost deathlike torpor which had frozen
the minds of mankind, were effectually roused. The Mussulmans displayed
a degree of energy and activity which have few parallels in the history
of the world: and after the conquests of the Mahometans were completed,
and the Califs quietly seated upon the greatest and most powerful
throne that the world had ever seen; after Almanzor, about the middle
of the eighth century, had founded the city of Bagdad, and settled a
permanent and flourishing peace, the arts and sciences, which usually
accompany such a state of society, began to make their appearance.
That calif founded an academy at Bagdad, which acquired much celebrity,
and gradually raised itself above all the other academies in his
dominions. A medical college was established there with powers to
examine all those persons who intended to devote themselves to the
medical profession. So many professors and pupils flocked to this
celebrated college, from all parts of the world, that at one time their
number amounted to no fewer than six thousand. Public hospitals and
laboratories were established to facilitate a knowledge of diseases,
and to make the students acquainted with the method of preparing
medicines. It was this last establishment which originated with the
califs that gave a first beginning to the science of chemistry.
In the thirteenth century the calif Mostanser re-established the
academy and the medical college at Bagdad: for both had fallen
into decay, and had been replaced by an infinite number of Jewish
seminaries. Mostanser gave large salaries to the professors, collected
a magnificent library, and established a new school of pharmacy. He was
himself often present at the public lectures.
The successor of Mostanser was the calif Haroun-Al-Raschid, the
perpetual hero of the Arabian tales. He not only carried his love for
the sciences further than his predecessors, but displayed a liberality
and a tolerance for religious opinions, which was not quite consistent
with Mahometan bigotry and superstition. He drew round him the
Syrian Christians, who translated the Greek classics, rewarded them
liberally, and appointed them instructors of his Mahometan subjects,
especially in medicine and pharmacy. He protected the Christian school
of Dschondisabour, founded by the Nestorian Christians, before the
time of Mahomet, and still continuing in a flourishing state: always
surrounded by literary men, he frequently condescended to take a part
in their discussions, and not unfrequently, as might have been expected
from his rank, came off victorious.
The most enlightened of all the califs was Almamon, who has rendered
his name immortal by his exertions in favour of the sciences. It
was during his reign that the Arabian schools came to be thoroughly
acquainted with Greek science; he procured the translation of a great
number of important works. This conduct inflamed the religious zeal
of the faithful, who devoted him to destruction, and to the divine
wrath, for favouring philosophy, and in that way diminishing the
authority of the Koran. Almamon purchased the ancient classics, from
all quarters, and recommended the care of doing so in a particular
manner to his ambassadors at the court of the Greek emperors. To Leo,
the philosopher, he made the most advantageous offers, to induce
him to come to Bagdad; but that philosopher would not listen to his
invitation. It was under the auspices of this enlightened prince, that
the celebrated attempt was made to determine the size of the earth by
measuring a degree of the meridian. The result of this attempt it does
not belong to this work to relate.
Almotassem and Motawakkel, who succeeded Almamon, followed his example,
favoured the sciences, and extended their protection to men of science
who were Christians. Motawakkel re-established the celebrated academy
and library of Alexandria. But he acted with more severity than his
predecessors with regard to the Christians, who may perhaps have abused
the tolerance which they enjoyed.
The other vicars of the prophet, in the different Mahometan states,
followed the fine example set them by Almamon. Already in the eighth
century the sovereigns of Mogreb and the western provinces of
Africa showed themselves the zealous friends of the sciences. One of
them called Abdallah-Ebn-Ibadschab rendered commerce and industry
flourishing at Tunis. He himself cultivated poetry and drew numerous
artists and men of science into his state. At Fez and in Morocco the
sciences flourished, especially during the reign of the Edrisites,
the last of whom, Jahiah, a prince possessed of genius, sweetness,
and goodness, changed his court into an academy, and paid attention
to those only who had distinguished themselves by their scientific
knowledge.
But Spain was the most fortunate of all the Mahometan states, and had
arrived at such a degree of prosperity both in commerce, manufactures,
population, and wealth, as is hardly to be credited. The three
Abdalrahmans and Alhakem carried, from the eighth to the tenth century,
the country subject to the Calif of Cordova to the highest degree of
splendour. They protected the sciences, and governed with so much
mildness, that Spain was probably never so happy under the dominion
of any Christian prince. Alhakem established at Cordova an academy,
which for several ages was the most celebrated in the whole world. All
the Christians of Western Europe repaired to this academy in search of
information. It contained, in the tenth century, a library of 280,000
volumes. The catalogue of this library filled no less than forty-four
volumes. Seville, Toledo, and Murcia, had likewise their schools of
science and their libraries, which retained their celebrity as long as
the dominion of the Moors lasted. In the twelfth century there were
seventy public libraries in that part of Spain which belonged to the
Mahometans. Cordova had produced one hundred and fifty authors, Almeria
fifty-two, and Murcia sixty-two.
The Mahometan states of the east continued also to favour the sciences.
An emir of Irak, Adad-El-Daula by name, distinguished himself towards
the end of the tenth century by the protection which he afforded
to men of science. To him almost all the philosophers of the age
dedicated their works. Another emir of Irak, Saif-Ed-Daula, established
schools at Kufa and at Bussora, which soon acquired great celebrity.
Abou-Mansor-Baharam, established a public library at Firuzabad in
Curdistan, which at its very commencement contained 7000 volumes. In
the thirteenth century there existed a celebrated school of medicine in
Damascus. The calif Malek-Adel endowed it richly, and was often present
at the lectures with a book under his arm.
Had the progress of the sciences among the Arabians been proportional
to the number of those who cultivated them, we might hail the Saracens
as the saviours of literature during the dark and benighted ages of
Christianity; but we must acknowledge with regret, that notwithstanding
the enlightened views of the califs, notwithstanding the multiplicity
of academies and libraries, and the prodigious number of writers, the
sciences received but little improvement from the Arabians. There are
very few Arabian writers in whose works we find either philosophical
ideas, successful researches, new facts, or great and new and important
truths. How, indeed, could such things be expected from a people
naturally hostile to mental exertion; professing a religion which
stigmatizes all exercise of the judgment as a crime, and weighed down
by the heavy yoke of despotism? It was the religion of the Arabians,
and the despotism of their princes, that opposed the greatest obstacles
to the progress of the sciences, even during the most flourishing
period of their civilization.[103] Fortunately chemistry was the
branch of science least obnoxious to the religious prejudices of the
Mahometans. It was in it, therefore, that the greatest improvements
were made: of these improvements it will be requisite now to endeavour
to give the reader some idea. Astrology and alchymy, they both derived
from the Greeks: neither of them were inconsistent with the taste of
the nation--neither of them were anathematized by the Mahometan creed,
though Islamism prohibited magic and all the arts of divination.
Alchymy may have suggested the chemical processes--but the Arabians
applied them to the preparation of medicines, and thus opened a new and
most copious source of investigation.
[103] For a fuller account of the progress of science among the
Arabians than would be consistent with this work, the reader is
referred to Mortucla’s Hist. des Mathématiques, i. 351; Sprengel’s
Hist. de la Médecine, ii. 246.
The chemical writings of the Arabians which I have had an opportunity
of seeing and perusing in a Latin dress, being ignorant of the original
language in which they were written, are those of Geber and Avicenna.
Geber, whose real name was Abou-Moussah-Dschafar-Al-Soli, was a Sabean
of Harran, in Mesopotamia, and lived during the eighth century. Very
little is known respecting the history of this writer, who must be
considered as the patriarch of chemistry. Golius, professor of the
oriental languages in the University of Leyden, made a present of
Geber’s work in manuscript to the public library. He translated
it into Latin, and published it in the same city in folio, and
afterwards in quarto, under the title of “Lapis Philosophorum.”[104]
It was translated into English by Richard Russel in 1678, under the
title of, “The Works of Geber, the most famous Arabian Prince and
Philosopher.”[105] The works of Geber, so far as they appeared in
Latin or English, consist of four tracts. The first is entitled, “Of
the Investigation or Search of Perfection.” The second is entitled, “Of
the Sum of Perfection, or of the perfect Magistery.” The third, “Of the
Invention of Verity or Perfection.” And the last, “Of Furnaces, &c.;
with a Recapitulation of the Author’s Experiments.”
[104] Boerhaave’s Chemistry (Shaw’s translation), i. 26. _Note._
[105] Golius was not, however, the first translator of Geber. A
translation of the longest and most important of his tracts into Latin
appeared in Strasburg, in 1529. There was another translation published
in Italy, from a manuscript in the Vatican. There probably might be
other translations. I have compared four different copies of Geber’s
works, and found some differences, though not very material. I have
followed Russel’s English translation most commonly, as upon the whole
the most accurate that I have seen.
The object of Geber’s work is to teach the method of making the
philosopher’s stone, which he distinguishes usually by the name of
_medicine of the third class_. The whole is in general written with so
much plainness, that we can understand the nature of the substances
which he employed, the processes which he followed, and the greater
number of the products which he obtained. It is, therefore, a book
of some importance, because it is the oldest chemical treatise in
existence,[106] and because it makes us acquainted with the processes
followed by the Arabians, and the progress which they had made in
chemical investigations. I shall therefore lay before the reader the
most important facts contained in Geber’s work.
[106] Of course I exclude the writings of the Greek ecclesiastics
mentioned in a previous part of this work, which still continue in
manuscript; because, I am ignorant of what they contain.
1. He considered all the metals as compounds of mercury and sulphur:
this opinion did not originate with him. It is evident from what he
says, that the same notion had been adopted by his predecessors--men
whom he speaks of under the title of the _ancients_.
2. The metals with which he was acquainted were _gold_, _silver_,
_copper_, _iron_, _tin_, and _lead_. These are usually distinguished
by him under the names of _Sol_, _Luna_, _Venus_, _Mars_, _Jupiter_,
and _Saturn_. Whether these names of the planets were applied to the
metals by Geber, or only by his translators, I cannot say; but they
were always employed by the alchymists, who never designated the metals
by any other appellations.
3. Gold and silver he considered as perfect metals; but the other four
were imperfect metals. The difference between them depends, in his
opinion, partly upon the proportions of mercury and sulphur in each,
and partly upon the purity or impurity of the mercury and sulphur which
enters into the composition of each.
Gold, according to him, is created of the most subtile substance of
mercury and of most clear fixture, and of a small substance of sulphur,
clean and of pure redness, fixed, clear, and changed from its own
nature, tinging that; and because there happens a diversity in the
colours of that sulphur, the yellowness of gold must needs have a like
diversity.[107] His evidence that gold consisted chiefly of mercury, is
the great ease with which mercury dissolves gold. For mercury, in his
opinion, dissolves nothing that is not of its own nature. The lustre
and splendour of gold is another proof of the great proportion of
mercury which it contains. That it is a fixed substance, void of all
burning sulphur, he thinks evident by every operation in the fire, for
it is neither diminished nor inflamed. His other reasons are not so
intelligible.[108]
[107] Sum of Perfection, book ii. part i. chap. 5.
[108] Ibid.
Silver, like gold, is composed of much mercury and a little sulphur;
but in the gold the sulphur is red; whereas the sulphur that goes to
the formation of silver is white. The sulphur in silver is also clean,
fixed, and clear. Silver has a purity short of that of gold, and a
more gross inspissation. The proof of this is, that its parts are not
so condensed, nor is it so fixed as gold; for it may be diminished by
fire, which is not the case with gold.[109]
[109] Ibid., chap. 6.
Iron is composed of earthy mercury and earthy sulphur, highly fixed,
the latter in by far the greatest quantity. Sulphur, by the work of
fixation, more easily destroys the easiness of liquefaction than
mercury. Hence the reason why iron is not fusible, as is the case with
the other metals.[110]
[110] Sum of Perfection, book ii. part i. chap. 7.
Sulphur not fixed melts sooner than mercury; but fixed sulphur opposes
fusion. What contains more fixed sulphur, more slowly admits of fusion
than what partakes of burning sulphur, which more easily and sooner
flows.[111]
[111] Ibid.
Copper is composed of sulphur unclean, gross and fixed as to its
greater part; but as to its lesser part not fixed, red, and livid,
in relation to the whole not overcoming nor overcome and of gross
mercury.[112]
[112] Ibid., chap. 8.
When copper is exposed to ignition, you may discern a sulphureous flame
to arise from it, which is a sign of sulphur not fixed; and the loss
of the quantity of it by exhalation through the frequent combustion
of it, shows that it has fixed sulphur. This last being in abundance,
occasions the slowness of its fusion and the hardness of its substance.
That copper contains red and unclean sulphur, united to unclean
mercury, is, he thinks, evident, from its sensible qualities.[113]
[113] Ibid.
Tin consists of sulphur of small fixation, white with a whiteness not
pure, not overcoming but overcome, mixed with mercury partly fixed and
partly not fixed, white and impure.[114] That this is the constitution
of tin he thinks evident; for when calcined, it emits a sulphureous
stench, which is a sign of sulphur not fixed: it yields no flame, not
because the sulphur is fixed, but because it contains a great portion
of mercury. In tin there is a twofold sulphur and also a twofold
mercury. One sulphur is less fixed, because in calcining it gives out
a stench as sulphur. The fixed sulphur continues in the tin after it
is calcined. He thinks that the twofold mercury in tin is evident, from
this, that before calcination it makes a crashing noise when bent, but
after it has been thrice calcined, that crashing noise can no longer
be perceived.[115] Geber says, that if lead be washed with mercury,
and after its washing melted in a fire not exceeding the fire of its
fusion, a portion of the mercury will remain combined with the lead,
and will give it the crashing noise and all the qualities of tin. On
the other hand, you may convert tin into lead. By manifold repetition
of its calcination, and the administration of fire convenient for its
reduction, it is turned into lead.[116]
[114] Ibid., chap. 9.
[115] Sum of Perfection, book ii. part i. chap. 9.
[116] Ibid.
Lead, in Geber’s opinion, differs from tin only in having a more
unclean substance commixed of the two more gross substances, sulphur
and mercury. The sulphur in it is burning and more adhesive to the
substance of its own mercury, and it has more of the substance of fixed
sulphur in its composition than tin has.[117]
[117] Ibid., chap. 10.
Such are the opinions which Geber entertained respecting the
composition of the metals. I have been induced to state them as nearly
in his own words as possible, and to give the reasons which he has
assigned for them, even when his facts were not quite correct, because
I thought that this was the most likely way of conveying to the reader
an accurate notion of the sentiments of this father of the alchymists,
upon the very foundation of the whole doctrine of the transmutation
of metals. He was of opinion that all the imperfect metals might be
transformed into gold and silver, by altering the proportions of the
mercury and sulphur of which they are composed, and by changing the
nature of the mercury and sulphur so as to make them the same with the
mercury and sulphur which constitute gold and silver. The substance
capable of producing these important changes he calls sometimes the
_philosopher’s stone_, but generally the _medicine_. He gives the
method of preparing this important _magistery_, as he calls it. But it
is not worth while to state his process, because he leaves out several
particulars, in order to prevent the foolish from reaping any benefit
from his writings, while at the same time those readers who possess the
proper degree of sagacity will be able, by studying the different parts
of his writings, to divine the nature of the steps which he omits, and
thus profit by his researches and explanations. But it will be worth
while to notice the most important of his processes, because this will
enable us to judge of the state of chemistry in his time.
4. In his book on furnaces, he gives a description of a furnace proper
for calcining metals, and from the fourteenth chapter of the fourth
part of the first book of his Sum of Perfection, it is obvious that the
method of calcining or oxidizing iron, copper, tin, and lead, and also
mercury and arsenic were familiarly known to him.
He gives a description of a furnace for distilling, and a pretty minute
account of the glass or stoneware, or metallic aludel and alembic,
by means of which the process was conducted. He was in the habit of
distilling by surrounding his aludel with hot ashes, to prevent it
from being broken. He was acquainted also with the water-bath. These
processes were familiar to him. The description of the distillation of
many bodies occurs in his work; but there is not the least evidence
that he was acquainted with ardent spirits. The term _spirit_ occurs
frequently in his writings, but it was applied to volatile bodies in
general, and in particular to sulphur and white arsenic, which he
considered as substances very similar in their properties. Mercury also
he considered as a spirit.
The method of distilling _per descensum_, as is practised in the
smelting of zinc, was also known to him. He describes an apparatus for
the purpose, and gives several examples of such distillations in his
writings.
He gives also a description of a furnace for melting metals, and
mentions the vessels in which such processes were conducted. He was
acquainted with crucibles; and even describes the mode of making
cupels, nearly similar to those used at present. The process of
cupellating gold and silver, and purifying them by means of lead, is
given by him pretty minutely and accurately: he calls it _cineritium_,
or at least that is the term used by his Latin translator.
He was in the habit of dissolving salts in water and acetic acid, and
even the metals in different menstrua. Of these menstrua he nowhere
gives any account; but from our knowledge of the properties of the
different metals, and from some processes which he notices, it is easy
to perceive what his solvents must have been; namely, the mineral acids
which were known to him, and to which there is no allusion whatever
in any preceding writer that I have had an opportunity of consulting.
Whether Geber was the discoverer of these acids cannot be known, as
he nowhere claims the discovery: indeed his object was to slur over
these acids, as much as possible, that their existence, or at least
their remarkable properties, might not be suspected by the uninitiated.
It was this affectation of secrecy and mystery that has deprived the
earliest chemists of that credit and reputation to which they would
have been justly entitled, had their discoveries been made known to the
public in a plain and intelligible manner.
The mode of purifying liquids by filtration, and of separating
precipitates from liquids by the same means, was known to Geber. He
called the process _distillation through a filter_.
Thus the greater number of chemical processes, such as they were
practised almost to the end of the eighteenth century, were known to
Geber. If we compare his works with those of Dioscorides and Pliny, we
shall perceive the great progress which chemistry or rather pharmacy
had made. It is more than probable that these improvements were made
by the Arabian physicians, or at least by the physicians who filled
the chairs in the medical schools, which were under the protection of
the califs: for as no notice is taken of these processes by any of the
Greek or Roman writers that have come down to us, and as we find them
minutely described by the earliest chemical writers among the Arabians,
we have no other alternative than to admit that they originated in the
east.
I shall now state the different chemical substances or preparations
which were known to Geber, or which he describes the method of
preparing in his works.
1. Common salt. This substance occurring in such abundance in the
earth, and being indispensable as a seasoner of food, was known from
the earliest ages. But Geber describes the method which he adopted to
free it from impurities. It was exposed to a red heat, then dissolved
in water, filtered, crystallized by evaporation, and the crystals being
exposed to a red heat, were put into a close vessel, and kept for
use.[118] Whether the identity of sal-gem (_native salt_) and common
salt was known to Geber is nowhere said. Probably not, as he gives
separate directions for purifying each.
[118] Investigation and Search of Perfection, chap. 3.
2. Geber gives an account of the two fixed alkalies, _potash_ and
_soda_, and gives processes for obtaining them. Potash was obtained by
burning cream of tartar in a crucible, dissolving the residue in water,
filtering the solution, and evaporating to dryness.[119] This would
yield a pure carbonate of potash.
[119] Invention of Verity, chap. 4.
Carbonate of soda he calls _sagimen vitri_, and salt of soda. He
mentions plants which yield it when burnt, points out the method of
purifying it, and even describes the method of rendering it caustic by
means of quicklime.[120]
[120] Search of Perfection, chap. 3.
3. Saltpetre, or nitrate of potash, was known to him; and Geber is the
first writer in whom we find an account of this salt. Nothing is said
respecting its origin; but there can be little doubt that it came from
India, where it was collected, and known long before Europeans were
acquainted with it. The knowledge of this salt was probably one great
cause of the superiority of the Arabians over Europeans in chemical
knowledge; for it enabled them to procure _nitric acid_, by means of
which they dissolved all the metals known in their time, and thus
acquired a knowledge of various important saline compounds, which were
of considerable importance.
There is a process for preparing saltpetre artificially, in several of
the Latin copies of Geber, though it does not appear in our English
translation. The method was to dissolve sagimen vitri, or carbonate of
soda, in aqua fortis, to filter and crystallize by evaporation.[121]
If this process be genuine, it is obvious that Geber must have been
acquainted with nitrate of soda; but I have some doubts about the
genuineness of the passage, because the term _aqua fortis_ occurs in
it. Now this term occurs nowhere else in Geber’s work: even when he
gives the process for procuring nitric acid, he calls it simply water;
but observes, that it is a water possessed of much virtue, and that it
constitutes a precious instrument in the hands of the man who possesses
sagacity to use it aright.
[121] De Investigatione Perfect. chap. 4.
4. Sal ammoniac was known to Geber, and seems to have been quite common
in his time. There is no evidence that it was known to the Greeks or
Romans, as neither Dioscorides nor Pliny make any allusion to it.
The word in old books is sometimes _sal armoniac_, sometimes _sal
ammoniac_. It is supposed to have been brought originally from the
neighbourhood of the temple of Jupiter Ammon: but had this been the
case, and had it occurred native, it could scarcely have been unknown
to the Romans, under whose dominions that part of Africa fell. In
the writings of the alchymists, sal ammoniac is mentioned under the
following whimsical names:
Anima sensibilis,
Aqua duorum fratrum ex sorore,
Aquila,
Lapis aquilinis,
Cancer,
Lapis angeli conjungentis,
Sal lapidum,
Sal alocoph.
Geber not only knew sal ammoniac, but he was aware of its volatility;
and gives various processes for subliming it, and uses it frequently
to promote the sublimation of other bodies, as of oxides of iron
and copper. He gives also a method of procuring it from urine, a
liquid which, when allowed to run into putrefaction, is known to
yield it in abundance. Sal ammoniac was much used by Geber, in his
various processes to bring the inferior metals to a state of greater
perfection. By adding it or common salt to aqua fortis, he was enabled
to dissolve gold, which certainly could not be accomplished in the
time of Dioscorides or Pliny. The description, indeed, of Geber’s
process for dissolving gold is left on purpose in a defective state;
but an attentive reader will find no great difficulty in supplying the
defects, and thus understanding the whole of the process.
5. Alum, precisely the same as the alum of the moderns, was familiarly
known to Geber, and employed by him in his processes. The manufacture
of this salt, therefore, had been discovered between the time when
Pliny composed his Natural History and the eighth century, when Geber
wrote; unless we admit that the mode of making it had been known to
the Tyrian dyers, but that they had kept the secret so well, that no
suspicion of its existence was entertained by the Greeks and Romans.
That they employed _alumina_ as a mordant in some of their dyes, is
evident; but there is no proof whatever that _alum_, in the modern
sense of the word, was known to them.
Geber mentions three alums which he was in the habit of using; namely,
icy alum, or Rocca alum; Jamenous alum, or alum of Jameni, and feather
alum. _Rocca_, or _Edessa_, in Syria, is admitted to have been the
place where the first manufactory of alum was established; but at what
time, or by whom, is quite unknown: we know only that it must have
been posterior to the commencement of the Christian era, and prior to
the eighth century, when Geber wrote. Jameni must have been another
locality where, at the time of Geber, a manufactory of alum existed.
_Feather alum_ was undoubtedly one of the native impure varieties of
_alum_, known to the Greeks and Romans. Geber was in the habit of
distilling alum by a strong heat, and of preserving the water which
came over as a valuable menstruum. If alum be exposed to a red heat
in glass vessels, it will give out a portion of sulphuric acid: hence
water distilled from alum by Geber was probably a weak solution of
sulphuric acid, which would undoubtedly act powerfully as a solvent of
iron, and of the alkaline carbonates. It was probably in this way that
he used it.
6. Sulphate of iron or copperas, as it is called (_cuperosa_), in the
state of a crystalline salt, was well known to Geber, and appears in
his time to have been manufactured.
7. Baurach, or borax, is mentioned by him, but without any description
by which we can know whether or not it was our borax: the probability
is that it was. Both glass and borax were used by him when the oxides
of metals were reduced by him to the metallic state.
8. Vinegar was purified by him by distilling it over, and it was used
as a solvent in many of his processes.
9. Nitric acid was known to him by the name of _dissolving water_. He
prepared it by putting into an alembic one pound of sulphate of iron of
Cyprus, half a pound of saltpetre, and a quarter of a pound of alum of
Jameni: this mixture was distilled till every thing liquid was driven
over. He mentions the red fumes which make their appearance in the
alembic during the process.[122] This process, though not an economical
one, would certainly yield nitric acid; and it is remarkable, because
it is here that we find the first hint of the knowledge of chemists of
this most important acid, without which many chemical processes of the
utmost importance could not be performed at all.
[122] Invention of Verity, chap. 23.
10. This acid, thus prepared, he made use of to dissolve silver: the
solution was concentrated till the nitrate of silver was obtained by
him in a crystallized state. This process is thus described by him:
“Dissolve silver calcined in solutive water (_nitric acid_), as before;
which being done, coct it in a phial with a long neck, the orifice of
which must be left unstopped, for one day only, until a third part of
the water be consumed. This being effected, set it with its vessel in
a cold place, and then it is converted into small fusible stones, like
crystal.”[123]
[123] Ibid., chap. 21.
11. He was in the habit also of dissolving sal ammoniac in this nitric
acid, and employing the solution, which was the aqua regia of the old
chemists, to dissolve gold.[124] He assures us that this aqua regia
would dissolve likewise sulphur and silver. The latter assertion is
erroneous. But sulphur is easily converted into sulphuric acid by the
action of aqua regia, and of course it disappears or dissolves.
[124] Ibid., chap. 23.
12. Corrosive sublimate is likewise described by Geber in a very
intelligible manner. His method of preparing it was as follows: “Take
of mercury one pound, of dried sulphate of iron two pounds, of alum
calcined one pound, of common salt half a pound, and of saltpetre a
quarter of a pound: incorporate altogether by trituration and sublime;
gather the white, dense, and ponderous portions which shall be found
about the sides of the vessel. If in the first sublimation you find it
turbid or unclean (which may happen by reason of your own negligence),
sublime a second time with the same fuses.”[125] Still more minute
directions are given in other parts of the work: we have even some
imperfect account of the properties of corrosive sublimate.
[125] Invention of Verity, chap. 8.
13. Corrosive sublimate is not the only preparation of mercury
mentioned by Geber. He informs us that when mercury is combined
with sulphur it assumes a red colour, and becomes cinnabar.[126] He
describes the affinities of mercury for the different metals. It
adheres easily to three metals; namely, lead, tin, and gold; to silver
with more difficulty. To copper with still more difficulty than to
silver; but to iron it unites in nowise unless by artifice.[127] This
is a tolerably accurate account of the matter. He says, that mercury is
the heaviest body in nature except gold, which is the only metal that
will sink in it.[128] Now this was true, applied to all the substances
known when Geber lived.
[126] Sum of Perfection, book i. part iii. chap. 4.
[127] Ibid., chap. 6.
[128] Ibid.
He gives an account of the method of forming the peroxide of mercury
by heat; that variety of it formerly distinguished by the name of _red
precipitati per se_. “Mercury,” he says, “is also coagulated by long
and constant retention in fire, in a glass vessel with a very long
neck and round belly; the orifice of the neck being kept open, that
the humidity may vanish thereby.”[129] He gives another process for
preparing this oxide, possible, perhaps, though certainly requiring
very cautious regulation of the fire. “Take,” says he, “of mercury
one pound, of vitriol (sulphate of iron) rubified two pounds, and of
saltpetre one pound. Mortify the mercury with these, and then sublime
it from rock alum and saltpetre in equal weights.”[130]
[129] Sum of Perfection, book i. part iv. chap. 16.
[130] Invention of Verity, chap. 10.
14. Geber was acquainted with several of the compounds of metals with
sulphur. He remarks that sulphur when fused with metals increases their
weight.[131] Copper combined with sulphur becomes yellow, and mercury
red.[132] He knew the method of dissolving sulphur in caustic potash,
and again precipitating it by the addition of an acid. His process is
as follows: “Grind clear and gummose sulphur to a most subtile powder,
which boil in a lixivium made of ashes of _heartsease_ and quicklime,
gathering from off the surface its oleaginous combustibility, until it
be discerned to be clear. This being done, stir the whole with a stick,
and then warily take off that which passeth out with the lixivium,
leaving the more gross parts in the bottom. Permit that extract to
cool a little, and upon it pour a fourth part of its own quantity of
distilled vinegar, and then will the whole suddenly be congealed as
milk. Remove as much of the clear lixivium as you can; but dry the
residue with a gentle fire and keep it.”[133]
[131] Sum of Perfection, book i. part iii. chap. 4.
[132] Ibid.
[133] Invention of Verity, chap. 6.
15. It would appear from various passages in Geber’s works that he was
acquainted with arsenic in the metallic state. He frequently mentions
its combustibility, and considers it as the _compeer_ of sulphur.
And in his book on _Furnaces_, chapter 25 (or 28 in some copies), he
expressly mentions _metallic arsenic_ (_arsenicum metallinum_), in a
preparation not very intelligible, but which he considered of great
importance. The white oxide of arsenic or arsenious acid, was obviously
well known to him. He gives more than one process for obtaining it by
sublimation.[134] He observes in his Sum of Perfection, book i. part
iv. chap. 2, which treats of sublimation, “Arsenic, which before its
sublimation was evil and prone to adustion, after its sublimation,
suffers not itself to be inflamed; but only resides without
inflammation.”
[134] Invention of Verity, chap. 7.
Geber states the fact, that when arsenic is heated with copper that
metal becomes white.[135] He gives also a process by which the white
arseniate of iron is obviously made. “Grind one pound of iron filings
with half a pound of sublimed arsenic (arsenious acid). Imbibe the
mixture with the water of saltpetre, and salt-alkali, repeating this
imbibation thrice. Then make it flow with a violent fire, and you will
have your iron white. Repeat this labour till it flow sufficiently with
peculiar dealbation.”[136]
[135] Sum of Perfection, book ii. part. ii. chap. 11.
[136] Invention of Verity, chap. 14.
16. He mentions oxide of copper under the name of _æs ustum_, the red
oxide of iron under the name of _crocus_ of iron. He mentions also
litharge and red lead.[137] But as all these substances were known to
the Greeks and Romans, it is needless to enter into any particular
details.
[137] Ibid., chap. 4 and 12.
17. I am not sure what substance Geber understood by the word
_marchasite_. It was a substance which must have been abundant, and in
common use, for he refers to it frequently, and uses it in many of his
processes; but he nowhere informs us what it is. I suspect it may have
been sulphuret of antimony, which was certainly in common use in Asia
long before the time of Geber. But he also makes mention of antimony
by name, or at least the Latin translator has made use of the word
_antimonium_. When speaking of the reduction of metals after heating
them with sulphur, he says, “The reduction of tin is converted into
clear antimony; but of lead, into a dark-coloured antimony, as we have
found by proper experience.”[138] It is not easy to conjecture what
meaning the word antimony is intended to convey in this passage. In
another passage he says, “Antimony is calcined, dissolved, clarified,
congealed, and ground to powder, so it is prepared.”[139]
[138] Sum of Perfection, book ii. part iii. chap. 10.
[139] Invention of Verity, chap. 4.
18. Geber’s description of the metals is tolerably accurate,
considering the time when he wrote. As an example I shall subjoin his
account of gold. “Gold is a metallic body, yellow, ponderous, mute,
fulged, equally digested in the bowels of the earth, and very long
washed with mineral water; under the hammer extensible, fusible, and
sustaining the trial of the cupel and cementation.”[140] He gives an
example of copper being changed into gold. “In copper-mines,” he says,
“we see a certain water which flows out, and carries with it thin
scales of copper, which (by a continual and long-continued course) it
washes and cleanses. But after such water ceases to flow, we find these
thin scales with the dry sand, in three years time to be digested with
the heat of the sun; and among these scales the purest gold is found:
therefore we judge those scales were cleansed by the benefit of the
water, but were equally digested by heat of the sun, in the dryness of
the sand, and so brought to equality.”[141] Here we have an example of
plausible reasoning from defective premises. The gold grains doubtless
existed in the sand before, while the scales of copper in the course of
three years would be oxidized and converted into powder, and disappear,
or at least lose all their metallic lustre.
[140] Sum of Perfection, book i. part iii. chap. 8.
[141] Ibid., book i. part iii. chap. 8.
Such are the most remarkable chemical facts which I have observed in
the works of Geber. They are so numerous and important, as to entitle
him with some justice to the appellation of the father and founder of
chemistry. Besides the metals, sulphur and salt, with which the Greeks
and Romans were acquainted, he knew the method of preparing sulphuric
acid, nitric acid, and aqua regia. He knew the method of dissolving
the metals by means of these acids, and actually prepared nitrate of
silver and corrosive sublimate. He was acquainted with potash and
soda, both in the state of carbonates and caustic. He was aware that
these alkalies dissolve sulphur, and he employed the process to obtain
sulphur in a state of purity.
But notwithstanding the experimental merit of Geber, his spirit of
philosophy did not much exceed that of his countrymen. He satisfied
himself with accounting for phenomena by occult causes, as was the
universal custom of the Arabians; a practice quite inconsistent with
real scientific progress. That this was the case will appear from the
following passage, in which Geber attempts to give an explanation
of the properties of the _great elixir_ or _philosopher’s stone_:
“Therefore, let him attend to the properties and ways of action of
the composition of the greater elixir. For we endeavour to make one
substance, yet compounded and composed of many, so permanently fixed,
that being put upon the fire, the fire cannot injure; and that it may
be mixed with metals in flux and flow with them, and enter with that
which in them is of an ingressible substance, and be fermented with
that which in them is of a permixable substance; and be consolidated
with that which in them is of a consolidable substance; and be
fixed with that which in them is of a fixable substance; and not be
burnt by those things which burn not gold and silver; and take away
consolidation and weights with due ignition.”[142]
[142] Investigation of Perfections, chap. 11.
The next Arabian whose name I shall introduce into this history, is
Al-Hassain-Abou-Ali-Ben-Abdallah-Ebn-Sina, surnamed Scheik Reyes, or
prince of physicians, vulgarly known by the name of _Avicenna_. Next to
Aristotle and Galen, his reputation was the highest, and his authority
the greatest of all medical practitioners; and he reigned paramount, or
at least shared the medical sceptre till he was hurled from his throne
by the rude hands of Paracelsus.
Avicenna was born in the year 978, at Bokhara, to which place his
father had retired during the emirate of the calif Nuhh, one of the
sons of the celebrated Almansor. Ali, his father, had dwelt in Balkh,
in the Chorazan. After the birth of Avicenna he went to Asschena in
Bucharia, where he continued to live till his son had reached his
fifteenth year. No labour nor expense was spared on the education of
Avicenna, whose abilities were so extraordinary that he is said to
have been able to repeat the whole Koran by heart at the age of ten
years. Ali gave him for a master Abou-Abdallah-Annatholi, who taught
him grammar, dialectics, the geometry of Euclid, and the astronomy of
Ptolemy. But Avicenna quitted his tuition because he could not give him
the solution of a problem in logic. He attached himself to a merchant,
who taught him arithmetic, and made him acquainted with the Indian
numerals from which our own are derived. He then undertook a journey
to Bagdad, where he studied philosophy under the great Peripatician,
Abou-Nasr-Alfarabi, a disciple of Mesue the elder. At the same time
he applied himself to medicine, under the tuition of the Nestorian,
Abou-Sahel-Masichi. He informs us himself that he applied with an
extraordinary ardour to the study of the sciences. He was in the habit
of drinking great quantities of liquids during the night, to prevent
him from sleeping; and he often obtained in a dream a solution of those
problems at which he had laboured in vain while he was awake. When the
difficulties to be surmounted appeared to him too great, he prayed to
God to communicate to him a share of his wisdom; and these prayers, he
assures us, were never offered in vain. The metaphysics of Aristotle
was the only book which he could not comprehend, and after reading them
over forty times, he threw them aside with great anger at himself.
Already, at the age of sixteen, he was a physician of eminence; and at
eighteen he performed a brilliant cure on the calif Nuhh, which gave
him such celebrity that Mohammed, Calif of Chorazan, invited him to his
palace; but Avicenna rather chose to reside at Dschordschan, where he
cured the nephew of the calif Kabus of a grievous distemper.
Afterwards he went to Ray, where he was appointed physician to Prince
Magd-Oddaula. Here he composed a dictionary of the sciences. Sometime
after this he was raised to the dignity of vizier at Hamdan; but he
was speedily deprived of his office and thrown into prison for having
favoured a sedition. While incarcerated he wrote many works on medicine
and philosophy. By-and-by he was set at liberty, and restored to his
dignity; but after the death of his protector, Schems-Oddaula, being
afraid of a new attempt to deprive him of his liberty, he took refuge
in the house of an apothecary, where he remained long concealed and
completely occupied with his literary labours. Being at last discovered
he was thrown into the castle of Berdawa, where he was confined for
four months. At the end of that time a fortunate accident enabled
him to make his escape, in the disguise of a monk. He repaired to
Ispahan, where he lived much respected at the court of the calif
Ola-Oddaula. He did not live to a great age, because he had worn out
his constitution by too free an indulgence of women and wine. Having
been attacked by a violent colic, he caused eight injections, prepared
from long pepper, to be thrown up in one day. This excessive use of so
irritating a remedy, occasioned an excoriation of the intestines, which
was followed by an attack of epilepsy. A journey to Hamdan, in company
with the calif, and the use of mithridate, into which his servant by
mistake had put too much opium, contributed still further to put an end
to his life. He had scarcely arrived at the town when he died in the
fifty-eighth year of his age, in the year 1036.
Avicenna was the author of the immense work entitled “Canon,” which
was translated into Latin, and for five centuries constituted the
great standard, the infallible guide, the confession of faith of the
medical world. All medical knowledge was contained in it; and nothing
except what was contained in it was considered by medical men as of any
importance. When we take a view of the Canon, and compare it with the
writings of the Greeks, and even of the Arabians, that preceded it, we
shall find some difficulty in accounting for the unbounded authority
which he acquired over the medical world, and for the length of time
during which that authority continued.
But it must be remembered, that Avicenna’s reign occupies the darkest
and most dreary period of the history of the human mind. The human
race seems to have been asleep, and the mental faculties in a state
of complete torpor. Mankind, accustomed in their religious opinions
to obey blindly the infallible decisions of the church, and to think
precisely as the church enjoined them to think, would naturally
look for some means to save them the trouble of thinking on medical
subjects; and this means they found fortunately in the canons of
Avicenna. These canons, in their opinion, were equally infallible with
the decisions of the holy father, and required to be as implicitly
obeyed. The whole science of medicine was reduced to a simple perusal
of Avicenna’s Canon, and an implicit adherence to his rules and
directions.
When we compare this celebrated work with the medical writings of the
Greeks, and even of the Arabians, the predecessors of Avicenna, we
shall be surprised that it contains little or nothing which can be
considered as original; the whole is borrowed from the writings of
Galen, or Ætius, or Rhazes: scarcely ever does he venture to trust his
own wings, but rests entirely on the sagacity of his Greek and Arabian
predecessors. Galen is his great guide; or, if he ever forsake him, it
is to place himself under the direction of Aristotle.
The Canon contains a collection of most of the valuable information
contained in the writings of the ancient Greek physicians, arranged,
it must be allowed, with great clearness. The Hhawi of Razes is almost
as complete; but it wants the _lucidus ordo_ which distinguishes the
Canon of Avicenna. I conceive that the high reputation which Avicenna
acquired, was owing to the care which he bestowed upon his arrangement.
He was undoubtedly a man of abilities, but not of inventive genius.
There is little original matter in the Canon. But the physicians in the
west, while Avicenna occupied the medical sceptre, had no opportunity
of judging of the originality of their oracle, because they were
unacquainted with the Greek language, and could not therefore consult
the writings of Galen or Ætius, except through the corrupt medium of an
Arabian version.
But it is not the medical reputation of Avicenna that induced me to
mention his name here. Like all the Arabian physicians, he was also a
chemist; and his chemical tracts having been translated into Latin, and
published in Western Europe, we are enabled to judge of their merit,
and to estimate the effect which they may have had upon the progress
of chemistry. The first Latin translation of the chemical writings of
Avicenna was published at Basil in 1572; they consist of two separate
books; the first, under the name of “Porta Elementorum,” consists of a
dialogue between a master and his pupil, respecting the mysteries of
Alchymy. He gives an account of the four elements, fire, air, water,
earth, and gives them their usual qualities of dry, moist, hot, and
cold. He then treats of air, which, he says, is the food of fire, of
water, of honey, of the mutual conversion of the elements into each
other; of milk and cheese, of the mixture of fire and water, and that
all things are composed of the four elements. There is nothing in
this tract which has any pretension to novelty; he merely retails the
opinions of the Greek philosophers.
The other treatise is much larger, and professes to teach the whole
art of alchymy; it is divided into ten parts, entitled “Dictiones.”
The first diction treats of the philosopher’s stone in general; the
second diction treats of the method of converting light things into
heavy, hard things into soft; of the mutation of the elements; and of
some other particulars of a nature not very intelligible. The third
diction treats of the formation of the elixir; and the same subject is
continued in the fourth.
The fifth diction is one of the most important in the whole treatise;
it is in general intelligible, which is more than can be said of those
that precede it. This diction is divided into twenty-eight chapters:
the first chapter treats of copper, which, he says, is of three kinds;
permenian copper, natural copper, and Navarre copper. But of these
three varieties he gives no account whatever; though he enlarges a good
deal on the qualities of copper--not its properties, but its supposed
medicinal action. It is hot and dry, he says, but in the calx of it
there is humidity. His account of the composition of copper is the same
with that of Geber.
The second chapter treats of lead, the third of tin, and in the
remaining chapters he treats successively of brass, iron, gold, silver,
marcasite, sulphuret of antimony, which is distinguished by the name of
alcohol; of soda, which he says is the juice of a plant called _sosa_.
And he gives an unintelligible process by which it is extracted from
that plant, without mentioning a syllable about the combustion to which
it is obvious that it must have been subjected.
In the twelfth chapter he treats of saltpetre, which, he says, is
brought from Sicily, from India, from Egypt, and from Herminia. He
describes several varieties of it, but mentions nothing about its
characteristic property of deflagrating upon burning coals. He then
treats successively of common salt, of sal-gem, of vitriol, of sulphur,
of orpiment, and of sal ammoniac, which, he says, comes from Egypt,
from India, and from Forperia. In the nineteenth and subsequent
chapters he treats of aurum vivum, of hair, of urine, of eggs, of
blood, of glass, of white linen, of horse-dung, and of vinegar.
The sixth diction, in thirty-three chapters, treats of the calcination
of the metals, of sublimation, and of some other processes. I think it
unnecessary to be more particular, because I cannot perceive any thing
in it that had not been previously treated of by Geber.
The seventh diction treats of the preparation of blood and eggs, and
the method of dividing them into their four elements. It treats also
of the elixir of silver, and the elixir of gold; but it contains no
chemical fact of any importance.
The eighth diction treats of the preparation of the ferment of silver,
and of gold. The ninth diction treats of the whole magistery, and of
the nuptials of the sun and moon; that is, of gold and silver. The
tenth diction treats of weights.
The chemical writings of Avicenna are of little value, and apply
chemistry rather to the supposed medical qualities of the different
substances treated of, than to the advancement of the science. All
the chemical knowledge which he possesses is obviously drawn from
Geber. Geber, then, may be looked upon as the only chemist among the
Arabians to whom we are indebted for any real improvements and new
facts. It is true that the Arabian physicians improved considerably the
materia medica of the Greeks, and introduced many valuable medicines
into common use which were unknown before their time. It is enough
to mention corrosive sublimate, manna, opium, asafœtida. It would
be difficult to make out many of the vegetable substances used by
the Arabian chemists; because the plants which they designated by
particular names, can very seldom be identified. Botany at that time
had made so little progress, that no method was known of describing
plants so as to enable other persons to determine what they were.