Al'chemy, the art of making gold and silver and of preparing a universal medicine. In ancient times it seems to have been cultivated to some extent by the Greeks and Chinese, and was learned by the Arabs in their invasions. In the middle ages it was looked upon as a science, and was earnestly studied among the nations of Europe. A university of alchemy was founded at Prague, and princes for a time kept their private alchemists.
The alchemists believed in the existence of a certain solid red preparation called the philosopher's stone or the grand elixir, which, when placed on common metals, such as lead, and melted to a liquid, would change them into gold. It would also cure all diseases, while a similar white preparation changed all metals to silver. In the study of this art many scientific truths were discovered, and so alchemy became the forerunner of chemistry.