[ ^I ] 



arrangement ; fo that fcarce any thing but a difFerence of fpecific 

 gravity can, while they are in full fufion, produce a feparation. 

 While cooling, fuch a feparation cannot poflibly take place, ac- 

 cording to our conceptions. On the other hand, if flony mafles 

 be once conceived diflblved in water, this fluid, occupying a. 

 much greater fpace, will allow them full room to concrete in 

 feparate mafles, according to the laws of their various affinities ; 

 and this is fo true, that if evaporation be carried too far, 

 they cannot be properly feparated by cryftallization. 



To clofe this controvcrfy, I fliall only add, that granite, 

 recently formed in the moift way, has frequently been found j 

 but no inftance can be produced of its formation by fire. 

 Thus a mole, having been conftrudled in the Oder in the year 

 1722, 350 feet long, 54 feet in height, 144 feet broad at 

 bottom, and 54 feet at the top, its fides only were 

 granite, without any other cement than mofs 5 the middle fpace 

 was entirely filled with granite fand. In a fliort time this con- 

 creted into a fubftance fo compad as to be impenetrable 

 by water *. Mr. Soulavie difcovered an enormous fiflTure in 

 a marble rock,' filled with granite matter, which mufl; have been 

 in a liquid ftate when the marble was already folid ; elfe it 

 would have mixed with it, and not have filled, as it was found 

 to do, all the finuofities of the calcareous rock f. 



* Lafius Hartz. f j Soulavie France Merid. 385. 



Vol. V. L 



