MONSTERS - THE MERCURIAL REBIS An alchemical figure designed to set out in graphic form the Three Principles of Salt, Sulphur and Mercury, as these manifest and interact in the human being. The three heads each designate one of the principles (from left to right, Salt, Sulphur and Mercury). The face that protrudes from the bulbous body represents the human being, who is invested with the two attributes of heavenly and infernal flight. The wings on the boots indicate that the whole figure is designed as a commentary on Philosophical Mercury, or the Mercury of the Alchemists. The woodcut - which appeared in several guises, in a number of alchemical works - has been attributed to Paracelsus.