HlSrORT of the SOCIETY. rj 



without flame, and burning with flame ; that is, on the pheno- 

 mena of combuftion and inflammation. 



In the combuftion of a piece of charcoal, two diftindl efl^edls 

 may be traced, viz. i. The oxygenating of the carbonic fub- 

 ftance, by which fixed air is produced, or carbonic acid in an 

 elaftic ftate ; 2. The production of a great quantity of hght 

 and heat, while the charcoal is undergoing this change. It is 

 with refpedl to this laft part of the procefs only that difl'erent 

 opinions are entertained. The phlogiftic theory maintains, that 

 in the oxygenation of the carbonic fubftance by the vital air, 

 the phlogiftic matter of that fubftance is fet free from combi- 

 nation with it, and in making its efcape exhibits the phenomena 

 of light and heat. 



Th e antiphlogiftic theory, on the other hand, fuppofes, that, 

 by the decompofition or the condenfation which the vital air 

 undergoes, while it oxygenates the carbonic fubftance, the la- 

 tent heat is transferred to that fubftance, and produces light and 



Now, if it cafl be Ihewn that a burning coal, though placed 

 in circumftances the naoft favourable for its oxygenation, may 

 Jiieverthelefs, l^-fe its heat, and ceafe to burn entirely, it is cer- 

 tain, that it is not alone by the calorique of the vital air that the 

 lire is fupported. Let then a confolidated piece of charcoal, fuch 

 ^s the mineral kingdom, in many places, affords in great perfec- 

 tion, be heated to the higheft degree of incandefcence, and 

 expofed, infnlated, to the atmofpheric air. Here every condi- 

 tiop, is united favourable to the oxygenation of the coal, a fuf- 

 fieient quantity of heat, and free accefs of air. If the heat, fup- 

 plied from the decompofition of the vital air, were able to main- 

 tain the heat of the coal, it would continue to burn \ but the 

 fadt is, that, in fuch a fituation as is here defcribed, the coal 

 IjOfes, its* h,eat, audit is atlail extinguifhed. It is plain, there- 



