494 



ILLUSTRATIONS OF THE 



arth 



fs th 



9 



m 151 times the fph 



oidal fliell. 

 The volume of the water, therefore, neceffary 



o hold in folution the materials of this 



jQiell 



IS 



to the volume of the whole earth as 625 to 151, 

 or in a greater ratio than that of four to one: and 

 fuch, therefore, at the very leaft, is the quantity 

 of water which Mr Kirwan fuppofes, after it cea- 

 fed to a6l in its chemical capacity, to have reti- 

 red into caverns in the interior of the earth. 

 Thus the Neptunifls, in their account of the 

 fpheroidal figure of the earth, are reduced to a 

 cruel dilemma, and are forced to choofe be- 

 tween a phyfical and a mathematical impoffi- 



bility. 



If we would inquire whether the opinion of 



the igneous origin of minerals, as commonly re- 

 ceived by the Vulcanifts, is capable of affording 

 a better folution of this difficulty, the theory of 

 M. de BufFon is the firft that prefents itfelf. 



433. That philofopher confiders the exiftence 

 of the fpheroidal figure as a proof that the whole 

 of the earth muft have been originally fluid ; and 

 as the fluidity of the whole can only be afcribed 

 to fufion, he has fuppofed that the earth was 

 originally a mafs of melted matter ft ruck off 

 from the fun by the coUifion of a comet ; and 

 that this mafs, when made to revolve on it^ 



axis 



ti 



tb 

 til 



fi 



h 



K 



« 



