sphere so as to be dry land, is no doubt a great
operation to be performed, and a difficult task to be explained; but
this is only an argument the more for philosophers to agree in adopting
the most reasonable means.

But though philosophers differ so widely in that point, this is not the
case with regard to the concretion of mineral bodies; here mineralists
seem to be almost all of one mind, at the same time without any reason,
at least, without any other reason than that false analogy which they
have inconsiderately formed from the operations of the surface of this
earth. This great misunderstanding of mineralists has such an extensive
and baneful effect in the judging of geological theories, that it
will be proper here to explain how that has happened, and to shew the
necessity of correcting that erroneous principle before any just opinion
can be formed upon the subject.

Fire and water are two great agents in the system of this earth; it is
therefore most natural to look for the operation of those agents in the
changes which are made on bodies in the mineral regions; and as the
consolidated state of those bodies, which had been collected at the
bottom of the sea, may have been supposed to be induced either by
fusion, or by the concretion from a solution, we are to consider how far
natural appearance lead to the conclusion of the one or other of those
two different operations. Here, no doubt, we are to reason analogically
from the known power and effects of those great agents; but, we must
take care not to reason from a false analogy, by misunderstanding the
circumstances of the case, or not attending to the necessary conditions
in which those agents act.--We must not conclude that fire cannot burn
in the mineral regions because our fires require the ventilation of the
atmosphere; for, besides the actual exigence of mineral fire being a
notorious matter of fact, we know that much more powerful means _may_
be employed by nature, for that mineral purpose of exciting heat, than
those which we practise.--We must not conclude that mineral marble is
formed in the same manner as we see a similar stony substance produced
upon the surface of the earth, unless we should have reason to suppose
the analogy to be complete. But, this is the very error into which
mineral philosophers have fallen; and this is the subject which I am now
to endeavour to illustrate.

The manner in which those philosophers have deceived themselves whe