HUTTONIAN THEORY. 



185 



ft 



\ 



'I 



li! 



to barytes, mentioned above, no conclufion can 

 be drawn as to the infufibility of the fame fub- 



ftance, w 



combined with the carb 



g 



The Carrara marble may require a heat of 

 6300° of Wedgewood, to melt it in the open 

 air, where the carbonic gas efcapes from it ; but 

 under fuch a preiTure as would retain this gas, 

 it cannot be inferred, that it might not melt 

 with the heat of a glafs-houfe furnace. In like 

 manner, it may be true, that two hundred 

 and eighty cubic inches of air, acting on 

 charcoal, cannot efl'ecl the fulion of one grain 

 of this marble, after its fixed air is driven off 

 from it ; but we cannot from thence draw any 

 inference, applicable to a cafe where the carbo- 

 nic gas is retained, and where the adion of heat 

 is independent of atmofpheric air. 



Nothing, therefore, can be more inconclufive 

 than this reafoning, as it proceeds on the fuppo- 

 fition, that Dr Mutton's fyftem admits propoli- 

 tions, which in fad it exprefsly denies. 



166. Of the produdion and maintenance of 



heat, in circumdances fo different from thofe of 

 ordinary e:K.perience, we can hardly be expected 

 to give any explanatior, ; but we are not entitled, 

 merely on that account, to doubt of the exiflence 

 of fuch heat. Mr Kirwan thinks otherwife : 

 ■'Judging," he fays, *' from all we atprefentknow 

 of heat, fuch a high degree of it, (as v/ill melt 

 jimcftone), could only be produced by the pu- 



refl; 



