English: XII. CLAVIS, the twelfth key, engraved by Matthaeus Merian (1593–1650). From Tripus aureus, hoc est, Tres tractatus chymici selectissimi, nempe I. Basilii Valentini, benedictini ordinis monachi, Germani, practica una cum 12. clavibus et appendice, ex germanico; II. Thomae Nortoni, angli philosophi crede mihi seu ordinale, ante annos 140. ab authore seriptum, nunc ex anglicano manuscripto in latinum translatum, phrasi eujusque authoris ut et sententia retenta; III. Cremeri cuiusdam abbatis westmonasteriensis angli testamentum, hactenus nondum publicatum, nunc in diversarum nationum gratiam editi, et figuris cupro affabre incisis ornati operâ et studio. Michaelis Maieri, phil. et med. d. com. p. &c. Francofurti, apud Hermannum à Sande. MDCLXXVII. as published in the collection Musaeum hermeticum, reformatum et amplificatum. Francofurti : Apud Hermannum à Sande, 1678. In Latin.

The part in question 'I. Basilii Valentini, benedictini ordinis monachi, Germani, practica una cum 12. clavibus et appendice, ex germanico;' or 'Basil Valentine, a German monk of the Benedictine order, one study with the twelve keys and the appendix, [translated] from the German.'

Inside a laboratory an alchemist stands, holding tongs in his left hand. With his right hand he points to a triangular crucible set on a bench, with the symbol of Mercury above it, from which grow two rose-like flowers. Through an open window behind the crucibe, the Sun and Moon can be seen. To the alchemist's left is a large barrel-shaped furnace from the top of which come flames and smoke. To his right are shelves with instruments and books. Below them, a lion holds the head of a snake in its jaws.