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degree of heat. Even if it could produce fome heat, nay an 

 intenfe heat, yet a heat productive of fluidity could never be 

 the confequcnce of attrition, for the inftant the bodies fubjecled 

 to it would acquire the firfl; degree of emollefcence, the calorific 

 power of atti'ition mufl neceffarily ceafe, 



Blt granting to our author (what we have fliewn to be 

 inconfiftent with his theory) fuch immenfe mafTes of coal,, 

 fulphur, and bitumen as mufl; be fuppofed colleded together, 

 to procure by their inflammation a heat of energy fufficient to 

 melt all the ftony fubfl:ances now exifting, I proceed to fliew, 

 that, confifl;ently with the laws of nature hitherto known to us, 

 either no inflammation at all could be produced, or at lead 

 none capable of producing the efi'ecfls required by him. To 

 produce inflammation the prefence of vital air is neceflary ; 

 to produce an immenfe inflammation of energy fufficient to 

 melt fl:ony fubftances, not only an immenfe collcdion of fuch 

 air, but of air of the greatefl: purity, is required. To produce 

 an inflammation, capable, if poflible, of melting ftony fub- 

 ftances withoiit effecfting either calcination or any other change 

 in them, an immenfe compreflion muft alfo be fuppofed. Now, 

 granting to our author a colledlion of coal, bitumen, &c. 

 fuflicient to produce a flame capable of fuch mighty 

 effedls, where fliall we find air to fupport that flame ? neither 

 coal nor bitumen produce vital air. But fuppofe this coal or 

 bitumen mixed with fubftances capable of giving out that air, 

 ftill that air would be fo impure, from the mixture of the 

 fixed and mephitic airs arifing from the coal or bitumen, as to 



be 



