Jabir b. Hayyan (the Geber of the Latins), who has been called one of the 'fathers of chemistry' and 'the most famous Arabic alchemist' , was one of the students of the Imam Ja'far, as-Sadiq. The quantity of Jabir's output is quite staggering: besides his writings in chemistry, he wrote 1,300 treatises on mechanics, 500 on medicine, and 500 against Greek philosophy, not to mention other subjects. The number of his books which have been printed in Latin, French and German since the 17th century comes to thirty, if we count his '500 booklets' as one book. There are 36 known manuscripts of his works in the British Museum, the Biblioteque Nationale in Paris and in other libraries in Germany. Egypt, Iran and Turkey. The extent to which he is indebted to the Imam Ja'far as-Sadiq in his research and teachings may be judged from the fact that in many of his books we find: 'My master and mawla. Ja'far. peace be upon him, told me that ...', and in his book, 'al Manfa'a' he explicitly says: 'I acquired this knowledge from Ja'far b. Muhammad, the leader of the people in his time.'
George Sarton, referring to Jabir's untranslated work, writes: '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 ...; 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 waterproof 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 mag- netic force.' He also discovered that each metal and material had a basic weight; he called this 'the knowledge of weights, 'ilm al-mawazin.' He was, in the words of Sarton: 'a very great personality, one of the greatest in mediaeval science.'