"Alchemy was a "pretended science by which gold and silver were to be made by the-transmutation of the baser metals into these substances, the agent of the transmutation being called the philosopher's stone." Those who professed this Art are supposed to have been either impostors or under a delusion created by impostors and mountebanks. This opinion has found its way into works on Science, and has been stereotyped in biographical dictionaries and...