which may be expressed in general by saying,
that they are mutually contained in, and contain each other.

Unless, therefore; every one of these different substances may be
dissolved in water, and crystallised from it, it is in vain to look for
the explanation of these appearances in the operations of nature, by the
means of aqueous solution.

On the other hand, heat being capable of rendering all these substances
fluid, they may be, with the greatest simplicity, transported from one
place to another; and they may be made to concrete altogether at
the same time, and distinctly separate in any place. Hence, for the
explanation of those natural appearances, which are so general, no
further conditions are required, than the supposition of a sufficient
intensity of subterraneous fire or heat, and a sufficient degree of
compression upon those bodies, which are to be subjected to that violent
heat, without calcination or change. But, so far as this supposition is
not gratuitous, the appearances of nature will be thus explained.

I shall only mention one specimen, which must appear most decisive
of the question. It is, I believe, from an Hungarian mine. In this
specimen, petro-silex, pyrites, and cinnabar, are so mixed together, and
crystallised upon each other, that it is impossible to conceive any one
of those bodies to have had its fluidity and concretion from a cause
which had not affected the other two. Now, let those who would deny the
fusion of this siliceous body explain how water could dissolve these
three different bodies, and deposit them in their present shape. If,
on the contrary, they have not the least shadow of reason for such a
gratuitous supposition, the present argument must be admitted in its
full force.

Sulphur and metals are commonly found combined in the mineral regions.
But this rule is not universal; for they are also frequently in a
separate state. There is not, perhaps, a metal, among the great number
which are now discovered, that may not be found native, as they are
called, or in their metallic state.

Metallic substances are also thus found in some proportion to the
disposition of the particular metals, to resist the mineralising
operations, and to their facility of being metallised by fire and
fusion. Gold, which refuses to be mineralised with sulphur, is found
generally in its native state. Iron, again, which is so easily
mineralised and scorified, is seldom found in its malleable state. T