Oswald Croll’s The Hermetic Touchstone (Hermetischer Probier Stein 1647)

Oswald Croll (1563 - 1609) was an alchemist and professor of medicine at the University of Marburg in Hesse, Germany. A strong proponent of alchemy and using chemistry in medicine, he was heavily involved in writing books and influencing thinkers of his day towards viewing chemistry and alchemy as two separate fields. Croll believed that chemistry and alchemy were two halves of a tightly related field, in the same way that organic and inorganic chemistry are related. He used the framework of Parcelsus’ works to organize his beliefs about the geometrically important relationships between various forms of matter and alchemical reactions, from rectangles to megagons.

The message of the Hermetischer Probier Stein can be approximately translated to ‘the Hermetic Touchstone in which every last one of the processes and chemical medicines found in Oswald Crolls’ work, entitled Royal Alchemist Treasure, is not only examinated and put to the test, but also complemented and enhanced in the Latin language, with various other beautiful and useful medicines tried by the author’s own hand and his daily experience.’