source of mighty revolutions in the fate of land.

There may, indeed, be some difficulty in conceiving all the
modifications of this mineral power; but as, on the one hand, we are not
arbitrarily to assume an agent, for the purpose of explaining events, or
certain appearances which are not understood; so, on the other, we must
not refuse to admit the action of a known power, when this is properly
suggested in the appearances of things; and, though we may not
understand all the modifications, or the whole capacity and regulation
of this power in bodies, we are not to neglect the appropriating to it,
as a cause, those effects which are natural to it, and which, so far as
we know, cannot belong to any other. On all occasions, we are to judge
from what we know; and, we are only to avoid concluding from our
suppositions, in cases where evidence or real information is necessarily
required. The subject now considered, subterraneous fire, will afford an
example of that truth; and, a general view of this great natural power
will here find a proper place, before the application of it for the
explanation of natural appearances.

No event is more the object of our notice, or more interesting as a
subject for our study, than is the burning of a fire: But, the more that
philosophers have studied this subject, the more they seem to differ
as to the manner in which that conspicuous event is to be explained.
Therefore, being so ignorant with regard to that fire of which we see
the origin as well as the more immediate effects, how cautious should
we be in judging the nature of subterraneous fire from the burning of
bodies, a subject which we so little understand.

But, though the cause of fire in general, or the operations of that
power in its extreme degrees, be for us a subject involved in much