An alchemist next to their athanor, the furnace used to create slow and steady heat for alchemical digestion. Also known as the Philosophical furnace, Slow Henry (Piger Henricus), Furnace of Arcana, and the Tower furnace. From Alchemy: Ancient and Modern by H. Stanley Redgrove, 1911. Colorized by Eve Harms. Licensed under CC0

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