This is the treas-ure-house in which are treasured up all the sublime things of science or wisdom or the glorious things which cannot be pos-sessed. . . . The house in which these treasures are is closed with four doors and they are locked with four keys
This passage establishes the Treasure House as the central alchemical symbol of Wisdom's totality, accessible only through mastery of all four elemental keys, constituting the passage's — and chapter's — defining thesis.
, Aurora Consurgens: A Document Attributed to Thomas Aquinas on the Problem of Opposites in Alchemy, 1966thesis