[27] See The Golden Tract concerning the Stone of the Philosophers (The Hermetic Museum, vol. i. p. 17).
The sulphur-mercury theory of the metals was held by such famous alchemists as Roger Bacon, Arnold de Villanova and Raymond Lully. Until recently it was thought to have originated to a great extent with the Arabian alchemist, Geber; but the late Professor Berthelot showed that the works ascribed to Geber, in which the theory is put forward, are forgeries of a date by which it was already centuries old (see [§ 32]). Occasionally, arsenic was regarded as an elementary principle (this view is to be found, for example, in the work Of the Sum of Perfection, by the pseudo-Geber), but the idea was not general.
The Sulphur-Mercury-Salt Theory.
§ 18. Later in the history of Alchemy, the mercury-sulphur theory was extended by the addition of a third elementary principle, salt. As in the case of philosophical sulphur and mercury, by this term was not meant common salt (sodium chloride) or any of those substances commonly known as salts. “Salt” was the name given to a supposed basic principle in the metals, a principle of fixity and solidification, conferring the property of resistance to fire. In this extended form, the theory is found in the works of Isaac of Holland and in those attributed to “Basil Valentine,” who (see the work Of Natural and Supernatural Things) attempts to explain the differences in the properties of the metals as the result of the differences in the proportion of sulphur, salt, and mercury they contain. Thus, copper, which is highly coloured, is said to contain much sulphur, whilst iron is supposed to contain an excess of salt, &c. The sulphur-mercury-salt theory was vigorously championed by Paracelsus, and the doctrine gained very general acceptance amongst the alchemists. Salt, however, seems generally to have been considered a less important principle than either mercury or sulphur.
The same germ-idea underlying these doctrines is to be found much later in Stahl’s phlogistic theory (eighteenth century), which attempted to account for the combustibility of bodies by the assumption that such bodies all contain “phlogiston”—the hypothetical principle of combustion (see [§ 72])—though the concept of “phlogiston” approaches more nearly to the modern idea of an element than do the alchemistic elements or principles. It was not until still later in the history of Chemistry that it became quite evident that the more obvious properties of chemical substances are not specially conferred on them in virtue of certain elements entering into their constitution.
Alchemistic Elements and Principles.
§ 19. The alchemists combined the above theories with Aristotle’s theory of the elements. The latter, namely, earth, air, fire and water, were regarded as more interior, more primary, than the principles, whose source was said to be these same elements. As writes Sendivogius in Part II. of The New Chemical Light: “The three Principles of things are produced out of the four elements in the following manner: Nature, whose power is in her obedience to the Will of God, ordained from the very beginning, that the four elements should incessantly act on one another so, in obedience to her behest, fire began to act on air, and produced Sulphur; air acted on water, and produced Mercury; water, by its action on the earth, produced Salt. Earth, alone, having nothing to act upon, did not produce anything, but became the nurse, or womb, of these three Principles. We designedly speak of three Principles; for though the Ancients mention only two, it is clear that they omitted the third (Salt) not from ignorance, but from a desire to lead the uninitiated astray.”[28]
[28] The New Chemical Light, Part II., Concerning Sulphur (see The Hermetic Museum, vol. ii. pp. 142-143).