ON THE THEORIES OF ELEVATION AND EARTHQUAKES. 45 
due to the change of external form. If this latter be tJie true supposition, as 
it will probably be thought to be, the above calculated results will be approxi¬ 
mately true, and will furnish unquestionable evidence of the inadmissibility 
of the hypothesis we have been considering respecting the origin of the earth’s 
spheroidal form ; for though the quantities we have to compare as the results 
of observation and the results of calculation are so small, the limits of error 
in the determination of them are too narrow to admit of even very much 
smaller discrepancies thaTj those exhibited in the results stated at the close of 
preceding paragraph, if the hypotheses on which the calculations are 
founded are true. 
'rbese particular dwerepaneios, however, only prove the inadmissibility of 
the above mode of accounting for the earth’s spheroidal form, when we adopt 
the byiiothesis above made respt^ting the primitive density of the terrestrial 
mass. ^ if we should adopt sonic other hypotluais respecting that density, 
we might undoubtedly account by this theory, not only for the earth s 
actual form, but also for the other phamoraena above mentioned. But it is 
to the necessity for such particular asiumpiions tlmt I would here again direct 
attention, as I have already done at the close of tlie preceding article. In any 
theory which assumes the earth’s primilivi! solidity, it is nm*?sary to make 
some arbitral^' hypotIiC!&l.s respecting its primitivo law of density; so that, in 
Buch theories as theme discussed in this and the preceding article, wliile we 
admit the general principle of reasoning before laid down (art?), in seeking 
for some secondary cause to which the earth’s form may be attributed, we 
reject in a great measure the application of tJiat princijile with reference to 
the earths rlensity; since we can only profess to account for it in such theo¬ 
ries, by means ot sorae particular and independent hypothesis adopted for 
the purpose. In tlie theory which admits the former Hiiidily of the earth, 
ere is no such inconsUtoiicy. No assumption is there made respecting the 
primitive constitution or density of the terrestrial mass, for the fluid state is 
only assumed to liave been some antecedent, and not necessarily its primitive 
8 te; and the present density of the lartli becomes as much the necessary 
consequence of physical causes as its form. The results also of this theory 
are all m perfect harmony with each otlitr; and wc can assert the undoubted 
adequacy of the causes assigned by it to produce the observed pliamomena; 
While, in the other theories we have discussed, a similar adequacy of causa¬ 
tion IS, 1 conceive, extremely doubtful. 
If then we admit Uie gtMieral principle of reasoning above alluded to, it 
appears to me that the theory which asserts the former fluidity of the globe 
as a much stronger claim to our preference than any other. If, on the con- 
rary, we reject that princijilo as a guide in our speculations in these remoter 
regions of ^oJogical scicoec, it would seem more consistent, In asamuing the 
• ^,?*^*?*'**^ solidity, also to assume that its present spheroidal form was 
originally impressed upon it, as being that form which would alone admit of 
an a mixture of land ami sea in ail latitudes, and which thus best adapts its 
Bor ace to be die habitation of those animate beings which it lia'‘ been des- 
m to support. But it must be incumbent on those who adopt this view of 
le subject to explain why, in thus denying tlmt the earth’s form and density 
are to be referred to secoodaiy causes, they reject, with reference to these 
p mnomena, a principle of reasoning and interpretation which they adadt witli 
erenee to geological phtenomfiia in goncval. and without which, in fact, 
geologj^^coiild have uo existence as a physical science. 
♦. ni^ritjenUion and Solidijicaluin uf die. Earth's Crust . —We may now 
proceed to consider the process of refrigeration and consequent solidification 
0 e terrestrial mass; and for this purpose I shall beg leave to quote a part 
