"THIS woodcut from The 12 Keys of Basil Valentine (1602) shows the four grades of fire with which alchemists worked: Elementary Fire (flames from the furnace), Celestial Fire (sun in the heavens), Central Fire of digestion and aging (lion eating a snake), and the Secret Fire of mind and inspiration (Mercury cipher between red and white roses).”
- The heavenly fire
- The central fire
- The fountain of nature
- The secret fire
- The invisible and most secret occult fire of the philosophers
- The general fire