g truth: All the
consolidated masses, of which we now inquire into the cause, are, upon
the surface of the earth, in a state of general decay, although the
various natures of those bodies admit of that dissolution in very
different degrees[4]

From every view of the subject, therefore, we are directed to look into
those consolidated masses themselves, in order to find principles from
whence to judge of those operations by which they had attained their
hardness or consolidated state.

It must be evident, that nothing but the most general acquaintance with
the laws of acting substances, and with those of bodies changing by the
powers of nature, can enable us to set about this undertaking with any
reasonable prospect of success; and here the science of Chemistry must
be brought particularly to our aid; for this science, having for its
object the changes produced upon the sensible qualities, as they are
called, of bodies, by its means we may be enabled to judge of that which
is possible according to the laws of nature, and of that which, in like
manner, we must consider as impossible.

[Note 4: Stalactical and certain ferruginous concretions may seem
to form an exception to the generality of this proposition. But an
objection of this kind could only arise from a partial view of things;
for the concretion here is only temporary; it is in consequence of a
solution, and it is to be followed by a dissolution, which will be
treated of in its proper place.]

Whatever conclusions, therefore, by means of this science, shall be
attained, in just reasoning from natural appearances, this must be held
as evidence, where more immediate proof cannot be obtained; and, in
a physical subject, where things actual are concerned, and not the
imaginations of the human mind, this proof will be considered as
amounting to a demonstration.

SECTION II.

An Investigation of the Natural Operations employed in consolidating
the Strata of the Globe.

We are now about to investigate those mineral operations of the globe by
which the qualities of hardness and solidity, consequently of strength
and durability, are procured to great bodies of this earth.

That those qualities are not original to such bodies, but actually
superinduced in the natural operations of the earth, will appear from
the examination of some of the hardest and most solid of those mineral
bodies. In such masses, (for example of flint and agate,) we find
included shells and