§ 15. The Alchemistic Elements.
The alchemists regarded the metals as composite, and granting this,
then the possibility of transmutation is only a logical conclusion. In
order to understand the theory of the elements held by them we must rid
ourselves of any idea that it bears any close resemblance to Dalton's
theory of the chemical elements; this is clear from what has been said
in the preceding chapter. Now, it is a fact of simple observation that
many otherwise different bodies manifest some property in common, as,
for instance, combustibility. Properties such as these were regarded as
being due to some principle or element common to all bodies exhibiting
such properties; thus, combustibility was thought to be due to some
elementary principle of combustion—the "sulphur" of the alchemists and
the "phlogiston" of a later period. This is a view which à
priori appears to be not unlikely; but it is now known that,
although there are relations existing between the properties of bodies
and their constituent chemical elements (and also, it should be noted,
the relative arrangement of the particles of these elements), it is the
less obvious properties which enable chemists to determine the
constitution of bodies, and the connection is very far from being of the
simple nature imagined by the alchemists.
