Edward Kelly's "Stone of the Philosophers" is an interesting work. Written by Kelly while under the imprisonment of Rudolph II, it was translated into English by Ashmole and, later, in a more usable form, by James Elliot. The material here, regarding alchemy, is twofold; Kelly's premises and secondary material from other works and philosophers he feels proves his points; that mercury, silver, and gold alone are used in the great work (with the exception of elixir from lead) and the refutation of various falsities of some of the authors of the age.