154 
ME. ROBERT MALLET ON VOLCANIC ENERGY. 
surface of the uplifted mass through the medium of some fluid, which may be conceived 
to be an elastic vapour, or, in other cases, a mass of matter in a state of fusion from 
heat. Every geologist, I conceive, who admits the action of elevatory forces at all will 
be disposed to admit the legitimacy of these assumptions.” The first effort of our 
elevatory force will of course be to raise the mass under which it acts, and to place it in 
a state of extension , and consequently of tension. 
21. If this fundamental notion be (as the writer believes it is) erroneous and opposed 
to all the facts observable in the great regions of elevation, i. e. in the mountain-chains of 
the world, then it must be admitted that the speculations which follow as to the forma- 
tion of fissures See. (in a word, the substance of the doctrines of this paper, however 
ingenious as a mathematical exercise) have no true reference to the facts as occurring in 
nature, and, promulgated with the authority of the author and with that sort of oracular 
sanction which mathematical symbols possess for those who are devoid of mathematical 
knowledge, have tended materially to retard the progress of a truer interpretation of 
elevatory forces. 
22. If we were to assume (as has been done) that the appearance of the masses of the 
great continents above the sea-level was a work of elevation at all, it might be a case to 
which Mr. Hopkins’s notion could perhaps apply. But that the great continents have 
not been the work of such elevatory forces at all, but have resulted from the deformation 
of a cooling and contracting globe covered only by a thin and yet flexible solidified 
crust, sinking over great areas and relatively or absolutely rising over others, has been 
so convincingly urged by Dana and other American geologists that it is probably now 
admitted. 
23. De la Beche’s notions as to elevation approached nearer to exactness than those 
of most of his contemporaries*; but to one man alone, Constant Peevost, belongs the 
honour of having clearly enunciated a true theory of elevatory forces, followed out by 
comparison with facts in nature, and by showing that these were inexplicable upon the 
notion of direct upheaval by a radial force from beneath. 
* [To cite even by name all the authors whose works contain scattered passages from which notices may be 
gleaned (always more or less vague, disjointed, or even inconsecutive) as to the relation between terrestrial 
refrigeration and the formation of continents, mountains, &c., is here impossible. De la Beche, in his 
‘ Researches in Theoretic Geology,’ 1834, pp. 121-162 et passim, writes far more clearly and connectedly than 
others of that period. His views, however, were anticipated by Peevost. Those who desire to trace more 
fully the history of this branch of knowledge will find somewhat ample references to past authors iu an able 
paper by Prof. Dana, “ On the Geological Resrilts of the Earth’s Contraction,” in Amer. Journ. of Science, 1847, 
vol. iii. ser. 2. 
The leading idea of the present Paper (namely, the showing that the deformations producing continents and 
sea-beds, the elevation of mountains and depression of valleys, and the origination of volcanic heat and energy 
are all due to a unique cause at different stages of its long-continued action) could not have been anticipated by 
any of the many eminent men above referred to, by Dana or by the writer, because the imperfect state of tire 
science of Thermo-Dynamics down to a later period rendered the leading idea itself impossible to them.] 
N.B. Passages in the test or footnotes which, like the present footnote, are enclosed in brackets were 
inserted in March or April 1873. 
