art: alchemy.
Alchemy: the branch of study and practical craft in the medieval and early renaissance period concerned with the nature and transformation of physical substances, esp. the transmutation of baser metals into gold; the physical and chemical transformation of metals and other substances performed by practitioners of this craft.
The chief goals of practical alchemy (the forerunner of modern chemistry and metallurgy) were the elixir (or philosopher's stone) which would transmute base metals into gold and/or prolong life indefinitely: the alkahest or universal solvent, and the panacea or universal remedy. However, many alchemical texts are more concerned with symbolic or mystical aspects of the study, and alchemy was frequently associated with astrology and other occult practices.
Source: OED.com