The greatest chemist of Islam has long been familiar to western readers
under the name of Geber, which is the medieval rendering of the Arabic
Jabir. Since the work of Paul Kraus we are on more solid ground with Jabir
ibn Haiyan.
He is Abu Musa Jabir ibn Haiyan al-Azdl (al-Tusl, al-~artusl, al-Harram
meaning that he was a Sabian?; al-Sufi). Flourished mostly in kufa. The
most famous Arabic' alchemist; the alchemist Geberu of the Middle Ages. He
may be the author of a book on the astrolabe, but his fame rests on his
alchemical writings preserved in Arabic: the 'Book of the Kingdom', the
'Little Book of the Balances', the 'Book of Mercury', the 'Book of
Concentration', the 'Book of Eastern Mercury', and others. According to
the treatises already translated (by Berthelot), his alchemical doctrines
were very anthropomorphic and animistic. But other treatises (not yet
available in translation) show him in a better light. We find in them
remarkably sound views on methods of chemical research; a theory on the
geologic formation of metals; the so-called sulphur-mercury theory of
metals (the six metals differ essentially because of different proportions
of sulphur and mercury in them); preparation of various substances (e.g.,
basic lead carbonate; arsenic and antimony from their sulphides). Jabir
deals also with various applications, e.g., refinement of metals,
preparation of steel, dyeing of cloth and leather, varnishes to
water-proof cloth and protect iron, use of manganese dioxide in glass
making, use of iron pyrites for writing in gold, distillation of vinegar
to concentrate acetic acid. He observed the imponderability of magnetic
force.
It is possible that some of the facts mentioned in the Latin works,
ascribed to Geber and dating from the twelfth century and later, must also
be placed to Jabir's credit. It is impossible to reach definite
conclusions until all the Arabic writings ascribed to Jabir have been
properly edited and discussed. It is only then that we shall be able to
measure the full extent of his contributions, but even on the slender
basis of our present knowledge, Jabir appears already as a very great
personality, one of the greatest in mediaeval science. Jabir admits the
Aristotelian theory about the composition of matter-earth, water, air,
fire-but he develops it along a different path. First, there are four
elementary qualities, or natures: heat, cold, dryness, humidity. When they
get together with a substance they form compounds of the first degree,
i.e. hot, cold, dry, wet. The union of two of these qualities gives
hot + dry + substance -------------- fire
hot + wet + substance -------------- air
cold + wet + substance ------------- water
cold + dry + substance ------------- earth
One of his chief contributions to the theory of chemistry lies in his
views upon the constitution of metals. To understand his conceptions
properly, we must hark back to Aristotle, whose philosophy of nature was
universally accepted in its main principles by the scientists of Islam.
According to Aristotle, it still be remembered, all substances are
composed of the four elements, fire, air, water, and earth, which are
themselves interconvertible. The immediate constituents of minerals and
metals are two exhalations, one an 'earthy smoke' and the other a watery
vapour'; the former consists of small particles of earth on the way to
becoming fire, while the latter consists of small particles of water on
the way to becoming air. Neither exhalation is ever entirely free from
some admixture of the other. Stones and other minerals are formed when the
two exhalations become imprisoned in the earth, the dry or smoky
exhalation predominating; metals are formed under similar circumstances if
the watery exhalation predominates.
Jabir accepted this theory of the constitution of metals, but appears to
have regarded it as too indefinite to explain observed facts or to afford
a guide to practical methods of transmutation. He therefore modified it in
such a fashion as to make it less vague, and the theory he suggested
survived, with some alterations and additions, until the beginning of
modern chemistry in the eighteenth century. The two exhalations, he
believed, when imprisoned in the bowels of the earth, are not immediately
changed into minerals or metals, but undergo an intermediate conversion.
The dry or smoky exhalation is converted into sulphur and the watery one
into mercury, and it is only by the subsequent combination of sulphur and
mercury that metals are formed. The reason of the existence of different
varieties of metals is that the sulphur and mercury are not always pure,
and that they do not always combine in the same proportion. If they are
perfectly pure and if, also, they combine in the most complete natural
equilibrium, then the product is the most perfect of metals, namely gold.
Defects in purity or proportion, or both, result in the formation of
silver, lead, tin, iron or copper, but since these metals are essentially
composed of the same constituents as gold, the accidents of combination
may be removed by suitable treatment. Such treatment is the object of
alchemy.
The idea that the transmutation of the metals was possible had the
excellent merit of provoking incessant experiment, but unfortunately the
alchemists were always prone to theorize to an inordinate extent.
Moreover, at Alexandria, the mystical beliefs of the Gnostics and the
Neo-Platonists - however admirable and attractive in themselves - had a
very detrimental effect upon experimental science. Alchemy thus became
less and less a matter for experimental research and more and more the
subject of ineffable speculation and superstitious practice, not to say
fraudulent deception.
The practical applications of chemistry were not neglected. Jabir
describes processes for the preparation of steel and the refinement of
other metals, for dyeing cloth and leather, for making varnishes to
waterproof cloth and to protect iron, for the preparation of hair-dyes and
so on. He gives a recipe for making an illuminating ink for manuscripts
from 'golden' marcasite, to replace the much more expensive one made from
gold itself, and he mentions the use of manganese dioxide in glass-making.
He knew how to concentrate acetic acid by the distillation of vinegar, and
was also acquainted with citric acid and other organic substances |