[Gutenberg 26340] • Of Natural and Supernatural Things / Also of the first Tincture, Root, and Spirit of Metals and Minerals, how the same are Conceived, Generated, Brought forth, Changed, and Augmented.

Canon Basilius Valentinus, also known under the Anglicized version of his name, Basil Valentine, was a 15th-century alchemist. So little is known about him that even his name cannot be corroborated; during the 18th century it was suggested that he was Johann Tholde. He wrote dozens of important publications on alchemy in Latin and German. They have been translated into many Western European languages, including English, French, and others. Roger Bacon, O.F. M. (c. 1214-1294), also known as Doctor Mirabilis (Latin: "wonderful teacher"), was an English philosopher and Franciscan friar who placed considerable emphasis on empiricism. He is sometimes credited as one of the earliest European advocates of the modern scientific method inspired by the works of Plato via early Islamic scientists. Bacon is also the ascribed author of the alchemical manual Speculum Alchemiae, which was translated into English as The Mirror of Alchimy in 1597. John Isaac Holland (active 1572-1610? ) was a Dutch alchemist who lived in the 15th century, but this is not assured. It was said that he was the first alchemist of Holland, and his techniques were praised by Paracelsus, Boyle, and Kunckel.