Engraving by Cornelius Nicolaus Schurtz. Above sits 'Philosophic Mercury', or 'Mercurius' in contemporary dress. Mercurius has a central place in alchemy, symbolising the universal agent of transmutation. Philosophical Mercury was made by union of sulphur and 'argent vive' (quicksilver, or mercury) represented by the serpent. Illustration from 'Tripus Hermeticus Fatidicus' ('The Prophetical Hermetic Tripod') by Johann Joachim Becher (1635-1682) published in Frankfurt in 1689. Becher is not only famous in the history of chemistry for his theory of combustion but is notable as a technologist, miner, metallurgist and he proposed many economic schemes. Despite its arcane title, this book contains much practical chemistry and mineralogy.
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