bstance
to which it is applied. We are but limited in the art of increasing the
heat or the cold of bodies; we find, however, extreme difference in
their substances with respect to fusibility.

A fusible substance, or mineral composition in a fluid state, is emitted
from those places of the earth at which subterraneous fire and expansive
force are manifested in those eruptive operations. In examining these
emitted bodies, men of science find a character for such productions, in
generalising the substance, and understanding the natural constitution
of those bodies. It is in this manner that such a person, finding a
piece of lava in any place of the earth, says with certainty, Here is a
stone which had congealed from a melted state.

Having thus found a distinguishing character for those fused substances
called, in general, Lavas, and having the most visible marks for that
which had been actually a volcano, naturalists, in examining different
countries, have discovered the most undoubted proofs of many ancient
volcanos, which had not been before suspected. Thus, volcanos will
appear to be not a matter of accident, or as only happening in a
particular place, they are general to the globe, so far as there is
no place upon the earth that may not have an eruption of this kind;
although it is by no means necessary for every place to have had those
eruptions.

Volcanos are natural to the globe, as general operations; but we are
not to consider nature as having a burning mountain for an end in her
intention, or as a principal purpose in the general system of this
world. The end of nature in placing an internal fire or power of heat,
and a force of irresistible expansion, in the body of this earth, is to
consolidate the sediment collected at the bottom of the sea, and to form
thereof a mass of permanent land above the level of the ocean, for the
purpose of maintaining plants and animals. The power appointed for this
purpose is, as on all other occasions, where the operation is important,
and where there is any danger of a shortcoming, wisely provided
in abundance; and there are contrived means for disposing of the
redundancy. These, in the present case, are our volcanos.

A volcano is not made on purpose to frighten superstitious people
into fits of piety and devotion, nor to overwhelm devoted cities with
destruction; a volcano should be considered as a spiracle to the
subterranean furnace, in order to prevent the unnecessary