alum, copperas, borax, silver nitrate, cinnabar, and corrosive sublimate, were prepared by them. They seem to have known of certain of the mineral acids, and were familiar with the solvent properties of aqua regia.
An examination of the literature of alchemy serves to show how its principles and tenets developed. The philosopher’s stone is first heard of in the twelfth century. Prior to that period the greater number of the Greek and Arabian writers contented themselves with affirming the fact of transmutation, without indicating how it might be accomplished. The universal medicine and the elixir of life were the products of a later age; no mention of them is known before the thirteenth century.
Alchemy flourished vigorously during the Middle Ages, and lingered on even until the early part of the nineteenth century. Its history is simply a long chapter in the history of human credulity. For the most part it is a record of self-deception, imposture, and fraud. It produced an abundant literature, mainly the work of ecclesiastics, between the seventh and fourteenth centuries; but as regards the artificial preparation of the noble metals or the discovery of the universal medicine or the elixir of life it was barren of result.
Although no clear line of demarcation is possible, it may be convenient, in dealing with the
