Book of Furnaces

The Liber fornacum, or Book of Furnaces, is a treatise by an unknown author known as Geber, who flourished in the 14th century. This work, along with others attributed to Geber, was highly influential in alchemy and metallurgy during the 14th and 15th centuries. Geber adopted the name to lend authority to his writings, which reflected contemporary European alchemical practices.1

The Book of Furnaces provided clear expressions of alchemical theory and laboratory directions, detailing the purification of compounds, preparation of acids, and the construction and use of laboratory apparatus, particularly furnaces. Geber's work also discussed the theory that all metals consist of sulfur and mercury and described the use of an elixir for transmuting base metals into gold. His rational approach and clear laboratory procedures helped establish alchemy as a more respectable field in Europe.1