Having thus, without employing the evidence of any fire or burning, been necessarily led to conclude an extreme degree of heat exerted in the mineral regions, I next inquire how far there are any appearances from whence we might conclude whether that active subterraneous power still subsists, and what may be the nature of that power.  When first I conceived my theory, naturalists were far from suspecting that basaltic rocks were of volcanic origin; I could not then have employed an argument from these rocks as I may do now, for proving that the fires, which we see almost daily issuing with such force from volcanos, are a continuation of that active cause which has so evidently been exerted in all times, and in all places, so far as have been examined of this earth.

With regard to the degree of heat in that subterraneous fire, our author, after proving that combustible materials would not burn in the mineral regions, then says, that suppose they were to burn, this would be “incapable of forming a heat even equal to that of our common furnaces, as Mr Dolomieu has clearly shown to be the case with respect to volcanic heat.”  The place to which he alludes, I believe to be that which I have quoted from the Journal de Physique (Part I. page 139) to which I here beg leave to refer the reader.  After what I have already said, this subject will appear to be of little concern to me; but, it must be considered, that my object, in these answers, is not so much to justify the theory which I have given, as it is to remove that prejudice which, to those who are not master of chemical and mineral subjects, will naturally arise from the opinion or authority of a scientific man, and a chemist; therefore, I think it my business to show how much he has misconceived the matter which he treats of, and how much he misunderstands the subject of my theory.

Mr Dolomieu alleges that the volcanic fire operates in the melting of bodies, not by the intensity of its heat, which is the means employed by us in our operations, but in the long continuance of its action.  But in that proposition, this philosopher is merely giving us his opinion; and, this opinion our author mistakes, I suppose, for the fact on which that opinion had been (perhaps reasonably) founded.  The reader will see, in the place quoted, or in the avant-propos to his Memoire sur les Iles Ponces, the fact to be this; That the Chevalier Dolomieu finds those bodies which we either cannot melt in our fires, or which we cannot melt without changing them by calcination and vitrification, he finds, I say, these substances had actually been melted with his lavas; he also finds those substances, which are necessarily dissipated in our fires, to have been retained in those melted mineral substances.  Had our author quoted the text, instead of giving us his own interpretation, he could not have offered a stronger confirmation of my theory; which certainly is not concerned with