Jabir ibn Hayyan (active latter 8th century), called Geber by Europeans, was reputedly the father of Moslem alchemy and chemistry.
It seems clear that there was a real person called Jabir ibn Hayyan about whom we know little except that he lived in al-Kufa, an important city of Abbasid Iraq, and that he had the reputation for skill in alchemy. There exists a vast body of Arabic writings attributed to this Jabir which could not possibly have been written by someone living in the late 8th century because the bulk of Greek scientific and al-chemical works had not been translated at that time; Arabic scientific terminology had not even been coined. The earliest biography of Jabir is contained in Ibn al-Nadim's Fihrist, a monumental bibliography compiled in 988; the author of the Fihrist is partially aware of such discrepancies but insists that Jabir was a historical personage.
Attributions to Jabir
Scholarship has shown that there was a sizable corpus of alchemical works attributed impossibly to the historical Jabir. The first references to these works by Jabir appear in the latter half of the 10th century. The corpus contains a great percentage of what medieval Islam knew of the scientific knowledge of the ancients, viewed through Islamic spectacles, and it appears impossible that the 9th- or 10th-century Jabir could have been a single man, however industrious. The Islamic point of view from which this encyclopedic collection of late Hellenistic science is viewed in the works of Jabir is an extremely heterodox one, and this is doubtless the reason for assigning its authorship to a long-deceased but actual Jabir of the 8th century.
Jabir's science of al-kimiya, from which Arabic word both "alchemy" and "chemistry" stem, was based upon the Hellenistic idea that all metals are fundamentally the same substance, but with varying impurities. The main object of alchemy was to discover a method which would transmute the base metals into the purest form of metal, gold; this could be done by means of a supposed substance called "red sulfur" by the Moslems and "the philosophers' stone" by Europeans. In the process of searching for red sulfur, Jabir and other Moslem alchemists developed a great many sound facts and processes which formed some of the basic building blocks for the science of chemistry.
In terms of practical methods evolved by Jabir and set forth in the almost 100 works ascribed to him, we are indebted to Moslem alchemy for methods of distillation, evaporation, crystallization, filtration, and sublimation. Methods of producing a considerable number of chemical substances are described: nitric acid, sulfuric acid, mercury oxide, lead acetate, and others.
Further Reading on Jabir ibn Hayyan
None of Jabir's works has been translated into English, but E. J. Holmyard, Alchemy (1957), is useful. See also "The Time of Jabir ibn Hayyan" in George Sarton, Introduction to the History of Science, vol. 1 (1927).