9* 



The oxigen of 

 fupporters con- 

 tains caloric. 



Combuftibles 

 and products 

 aifo refemble 

 each other : 



But the former 

 emit fire when 

 they combine 

 with oxigen. 



Combuftibles con- 

 tain light . 



When fupporters 

 and combuftibles 

 combine, the 

 caloric and light 

 fly off in the 

 combination called 

 fire. 



Combuftion will 

 notenfue if ei- 

 ther of thefc in- 



REMARRS ON COMBUSTION. 



mufl conclude that this oxigen in the fupporters contains fomc- 

 thing which the oxigen of the products wants, fomething which 

 feparates during the paflage of the oxigen from the product to 

 the combuflible, and occafions the combuflion, or emiflion of 

 fire, which accompanies this paffage. The oxigen of fup- 

 porters then contains fome ingredient which the oxigen of 

 produces wants. Many circumftances concur to render it pro- 

 bable that this ingredient is caloric. 



The combujlibles and the producls alfo refcmble each other in 

 feveral refpects. Both of them contain the fame or a fimilar 

 bafe ; both frequently combine with combuftibles, and like- 

 wife with oxigen; but they differ effentially in the phenome- 

 na which accompany their combination with oxigen. In the 

 one cafe^re is emitted, in the other not. If we recollect that 

 no fubftance but a combuflible is capable of reftoring combuf- 

 tibility to the bafe of a product, and that at its doing fo it al- 

 ways lofes its own combuflibility ; and if we recollect farther, 

 that the bafe of a product does not exhibit the phenomena of 

 combuflion even when it combines with oxigen, we cannot 

 avoid concluding, that all combuftibles contain an ingredient 

 which they Iofe when converted into products and that this 

 lofs contributes to the fire which makes its appearance during 

 the converfion. Many circumftances contribute to render it 

 probable that this ingredient is light. 



If we fuppofe that the oxigen of fupporters contains caloric 

 as an effential ingredient, and that light is a component part of 

 all combuftibles, the phenomena of combuflion above enumer- 

 ated, numerous and intricate as they are, admit of an eafy and 

 obvious explanation. The component parts of the oxigen of 

 fupporters are two ; namely, I . a bafe, 2. caloric : The com- 

 ponent parts of combuftibles are like wife two; namely, 1. a 

 bafe, 2. light. During combuflion the bafe of the oxigen 

 combines with the bafe of the combuflible, and forms the pro- 

 duct ; while at the fame time the caloric of the oxigen com- 

 bines with the light of the combuflible, and the compound flies 

 offin the form of fire. Thus combuflion is a double decompo- 

 fition; the oxigen and combuflible divide themfelves each into 

 two portions, which combine in pairs ; the one compound is 

 the producl, and the other the fire, which efcapes. 



Hence thereafon that the oxigen of products is unfit for com- 

 buflion. It wants its caloric. Hence the reafon that combuf- 



tion 



