The word is derived from the Arabic al (the) and kemia (excellent), and signifies the most exalted science. It is a branch of chemistry, the objects of which were the transmutation of inferior metals to gold; the discovery of an elixir vitae, or universal medicine; an universal solvent; and other visionary and impracticable schemes. The Saracens are supposed to have first introduced the art into Europe; and so eagerly was it pursued by many of the most exalted in station and even in knowledge, that monarchs have not been ashamed to practise it, or to be duped by it. It is said that the Emperor Caligula endeavoured to obtain gold from the sulphuret of arsenic; and Edward I. witnessed an attempt made by Raymond Lully to obtain the precious metal from iron, which it was believed he accomplished. Most of the alchemists imagined that gold was the only elementary metal, and that the others were merely gold contaminated by foreign matters, from which it was possible to separate it. It was also imagined that mercury might be solidified, and that silver would be the result. In these futile pursuits many lives were spent, and splendid fortunes sacrificed.

The art of the professors of alchemy was shrouded in mystery, which none but the initiated could penetrate.

Their language was symbolical, and they either believed or propagated the notion that supernatural influence was necessary, and might be commanded in their pursuits. The student was sometimes required to qualify himself for the attainment of his object by acts of devotion and charity. The operations were by some only attempted when planetary influence was supposed favourable to success. So many exalted per sons became the dupes and victims of the professors of alchemy, that in the reign of Henry IV. an act was passed prohibiting all attempts to make gold or silver under the pain of felony. From the numerous well-authenticated instances of persons having procured gold by certain mystical operations with the aid of fire, it is generally believed that a fraudulent slight of hand was practised. A hollow rod, containing gold dust, is said to have been employed in stirring the contents of the crucible, or the precipitated solution of gold used as a component in the powder of projection. In these ridiculous attempts, however, many valuable chemical discoveries were accidentally made.

Porcelain china was first obtained by an alchemist in search of the philosopher's stone.