Coelum philosophorum seu De secretis naturæ. Liber. Philippo Ulstadio patricio Nirenbergensi. Authore.
Coelum philosophorum, a 1525 alchemical treatise attributed to Philipp Ulstad, probably printed in Strasbourg and held in a Paris pharmacy-college library, addressed to a patrician of Nuremberg. Its woodcuts show glass distillation apparatus such as retorts, alembics and vessels set in sand baths and furnaces, drawn with dense hatching and clear outlines that suggest useful models for technical diagrams and scientific line illustration.
