306 OUTLINES OF NATURAL PHILOSOPHY. 



If the whole mass of the Earth was ever in a fluid- 

 state, it must have been so from the action of heat. 

 The insolubility of the greatest part of rocks and 

 minerals in water, and the immense bulk of wa- 

 ter that would be required for dissolving even 

 those that are soluble, are insuperable objections 

 to the hypothesis of aqueous formation. The 

 igneous formation is not subject to either of these 

 difficulties. 



The spheroidal figure may also have been gradually 

 acquired without supposing the original fluidity of 

 the whole mass. 



309. If in a terraqueous body, however irre- 

 gular in its primitive form, the prominent parts 

 are subject to be worn down, and the detritus io 

 be carried to the lower parts, occupied by wa- 

 ter, where they acquire a horizontal stratifica- 

 tion, and are, by certain mineral operations, 

 afterwards consolidated into stone ; such a 

 body, in the course of ages, must acquire a sur- 

 face every where at right angles to the direc- 

 tion of gravity, and consequently more or less 

 approximating to a spheroid of equilibrium. 



The natural history of the Earth gives great coun- 

 tenance to the suppositions here introduced ; 

 which therefore seem to furnish a very rational 

 explanation of the ellipticity belonging to the 



Earth 



