Nine Books on the Nature of Things

Sulphur is mortified by removing its combustible, stinking fatness and reducing it to a fixed substance. This is done as follows. Take common yellow sulphur reduced to fine powder and draw very acrid aqua fortis from it by distillation three times. Then sweeten the black sulphur remaining at the bottom with fresh water, repeatedly distilling it off until the water leaves entirely sweet and no longer smells of sulphur. Reverberate this sulphur in a closed reverberatory as with Antimony: it will first become white, then yellow, and thirdly red like cinnabar. When it has reached this condition you should rejoice, for it is the beginning of your riches. This reverberated sulphur tinges any Silver very deeply into the most excellent gold and the human body into its highest health, beyond what it is lawful to write: such is the virtue of this reverberated and fixed sulphur.