Pseudo-Geber ("false Geber") is the name assigned by modern scholars to an alchemist born in the 13th century, probably Paul of Taranto in Spain. He wrote a few books on alchemy and metallurgy, in Latin, under the pen name of Geber (Jabir Ibn Haiyan), the 8th century Islamic alchemist with the same name. Pseudoepiaphy is very common in alchemical writing. Many works were ascibed to Aristole and other Greeks(also Egyptians) by the early Persian and Arabian alchemists. This trend continues thru the entire history of alchemy.

Books from the arabic corpus of Jabir Ibn Hayyan had been translated into Latin during the 11th to 13th centuries, and had made a profound impression on European alchemists. Pseudo-Geber probably adopted the name of his illustrious predecessor in order to capitalize on his reputation. Pseudo-Geber's work also reflects 14th century European alchemical practices based on earlier Arabic ones.

Five of his works have survived, dated from about 1310:

• Summa perfectionis magisterii ("The Height of the Perfection of Mastery").
• Liber fornacum ("Book of Stills"),
• De investigatione perfectionis ("On the Investigation of Perfection"), and
• De inventione veritatis ("On the Discovery of Truth").
• '' Testamentum gerberi

Publication of parts of the corpus began in1518 and continued until 1541 when a more complete (and much edited) book was published. Being the clearest expression of alchemical theory and laboratory directions available until then — in a field where mysticism, secrecy, and obscurity were the usual rule — Pseudo-Geber's books were widely read and extremely influential among European alchemists. It is from the Latin manuscripts (corpus) that we get the first recipes for mineral acids

Pseudo-Geber was instrumental in spreading alchemical theories throughout western Europe. He assumed that all metals are composed of unified sulfur and mercury copuscles and gave detailed descriptions of metallic properties in those terms. He also explained the use of an elixir in transmuting base metals into gold (see philosopher's stone).

Pseudo-Geber defended alchemy in the Summa giving it a firm and respectable position in Europe. His practical directions for laboratory procedures were so clear that it is obvious he was familiar with many chemical operations.

Pseudo-Geber's works on chemistry were not equaled in their field until the 16th century with the appearance of the writings of the Italian chemist Vannoccio Biringuccio, the German mineralogist Georgius Agricola, and the German alchemist Lazarus Ercker.

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