This plate forms part of Johann Rudolf Glauber's treatise ‘The Prosperity of Germany’ and illustrates various stages in ‘the Preparation of Salt-petre’ (nitre). The two images at the top show ‘the manner of Boiling Salt-petre, and … by what means a Lixivium is to be made out of a Nitrous Earth’, according to the methods of another German chemist, Lazarus Ercker. The lower image shows the preparation of the ‘Lixivium’ of saltpetre from horse dung or the leaves of trees.
Plate facing p. 339 in the book The works of the highly experienced and famous chymist, John Rudolph Glauber, containing great variety of choice secrets in medicine and alchymy … (English translation by Christopher Packe, London, 1689).
Glauber (ca. 1604–70), an alchemist, chemist and chemical engineer, made several improvements to chemical processes and equipment, including furnaces and devices used in distillation. He published more than 40 books in his lifetime, the most significant of which were collated and translated into English by Christopher Packe (a follower of Robert Boyle) to form a posthumous ‘collected works’ edition.