We have had but two theories, with regard to the transformation of those bodies which have had a known origin, or to the change of their substance and consistence; the one of these which I have given is that of heat or fusion; the other, which I wish to be compared with mine, is that of water and infiltration.  It is by this last that all authors hitherto, in one shape or another, have endeavoured to explain the changes that those strata must have undergone since the time of their first formation at the bottom of the sea.  They indiscriminately apply the doctrine of infiltration to those strata of mineral coal as to any other; they say that bituminous matter is infiltrated with the water, impregnates certain strata of earth with bituminous matter, and thus converts them into mineral coal, and bituminous strata.  This is not reasoning physically, or by the inductive method of proceeding upon matter of fact; it is reasoning fantastically, or by making gratuitous supposition founded merely on imagination.  It was thus that natural philosophers reasoned before the age of science; the wonder now is, how men of science, in the present enlightened age, should suffer such language of ignorance and credulity to pass uncensured.

The subject which I am now to treat of consists of peculiar strata of the earth, bodies which we may investigate through all the stages of their change, which is extreme; for, from vegetable bodies produced upon the habitable earth, they are now become a mineral body, and the most perfect coal,—­a thing extremely different from what it had been, and a thing which cannot be supposed to have been accomplished by the operation of water alone, or any other agent in nature with which we are acquainted, except the action of fire or heat.  It is therefore impossible for a philosopher, reasoning upon actual physical principles, not to acknowledge in this a complete proof of the theory which has been given, and a complete refutation of that aqueous operation which has been so inconsiderately supposed as consolidating the strata of the earth, and forming the various mineral concretions which are found in that great body.

To see this, it will be sufficient to trace the progress of vegetable and animal substances, (bodies which had certainly lived by means of a former earth), to this changed state in which they have become perfect mineral bodies, and constitute a part of the present earth.  For, as these changes are perfectly explained by the one theory, and absolutely inconsistent with the other, there arises from this a conviction that must be irresistible to a person who can give proper attention to a chain of reasoning from effect to cause.