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HUTTONIAN THEORT. 



49 f 





r 



f 

 I 



the poles, does not conned: that fad with the a- 

 ther fads in the natural hillory of the globe, and 

 fails, therefore, in the point mod eJTential to a 

 theory. It is liable, alfo, to other objedions ; 

 whether it be conceived to have proceeded from 

 lire or from water ; whether it has happened on 

 the principles of Buffbn or of Werner. 



430. Firft, let us fuppofe that the fluidity of 

 the earth, or of the external craft of it, at leafl 

 to a certain depth, proceeded from a folution 

 of the whole in the waters of the ocean ; and, 

 waving all the objedions that have been ftated 

 to this hypothefis, on account of the abfolute in- 

 folubility of many mineral fubllances in wa- 

 ter, let us fuppofe them all foiuble in a certain 

 degree, and let us compute the quantity of the 

 menftruum, which, on the fuppofitions raoft fa- 

 vourable to the fyftem, muil have been required 

 to this great geologico-chemical operation. 



The liliceous earth, though not foiuble in wa- 

 Urperfe, yet, after being diilblved in that fluid 

 by means of an alkali, was found by Dr Black, 

 in his analyfis of the Geyfer water, to remain 

 fufpended in a quantity of Water, between 500 

 and 1000 times its own weight. This is one of 

 the fads moft favourable to the Neptunian the- 

 ory ; and that every advantage may be given to 

 that theory, we fliall take the leaft of the num- 

 bers juft mentioned, and fuppofe that filiceous 



earth 



