§ 17. The Sulphur-Mercury Theory.
Coming to the alchemists, we find the view that the metals are all
composed of two elementary principles—sulphur and mercury—in different
proportions and degrees of purity, well-nigh universally accepted in the
earlier days of Alchemy. By these terms "sulphur" and "mercury,"
however, must not be understood the common bodies ordinarily designated
by these names; like the elements of Aristotle, the alchemistic
principles were regarded as properties rather than as substances, though
it must be confessed that the alchemists were by no means always clear
on this point themselves. Indeed, it is not altogether easy to say
exactly what the alchemists did mean by these terms, and the question is
complicated by the fact that very frequently they make mention of
different sorts of "sulphur" and "mercury." Probably, however, we shall
not be far wrong in saying that "sulphur" was generally regarded as the
principle of combustion and also of colour, and was said to be present
on account of the fact that most metals are changed into earthy
substances by the aid of fire; and to the "mercury," the metallic
principle par excellence, was attributed such properties as
fusibility, malleability and lustre, which were regarded as
characteristic of the metals in general. The pseudo-Geber (see §
32) says that "Sulphur is a fatness of the Earth, by temperate Decoction
in the Mine of the Earth thickened, until it be hardned{sic} and made
dry."3 He considered an excess of
sulphur to be a cause of imperfection in the metals, and he writes
that one of the causes of the corruption of the metals by fire "is the
Inclusion of a burning Sulphuriety in the profundity of their Substance,
diminishing them by Inflamation, and exterminating also into Fume, with
extream Consumption, whatsoever Argentvive in them is of good
Fixation."
4 He assumed, further, that
the metals contained an incombustible as well as a combustible sulphur,
the latter sulphur being apparently regarded as an impurity.
5 A later alchemist says that sulphur is
"most easily recognised by the vital spirit in animals, the colour in
metals, the odour in plants."
6 Mercury,
on the other hand, according to the pseudo-Geber, is the cause of
perfection in the metals, and endows gold with its lustre. Another
alchemist, quoting Arnold de Villanova, writes: "Quicksilver is the
elementary form of all things fusible; for all things fusible, when
melted, are changed into it, and it mingles with them because it is of
the same substance with them. Such bodies differ from quicksilver in
their composition only so far as itself is or is not free from the
foreign matter of impure sulphur."
7 The
obtaining of "philosophical mercury," the imaginary virtues of which the
alchemists never tired of relating, was generally held to be essential
for the attainment of the
magnum opus. It was commonly thought
that it could be prepared from ordinary quicksilver by
purificatory processes, whereby the impure sulphur supposed to be
present in this sort of mercury might be purged away.
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.
