IB REMARKS ON COMBUSTION. 



may be termed partial combuftibles; indicating by the name, 

 Since product that a part only of the bafe is capable of undergoing combuftion. 

 with oxigen, but Now fince the produces of combuftion are capable of corn- 

 never exhibit bining with oxigen, but never exhibit the phenomena of com- 



kTthe^be *"r- buftion exce Pt when the y are in the # ate ° f partial combuf- 



tial combufiibUif tibles, combuftible bodies mull: contain iome principle which 



combuftibles t | iey ] f e during combuftion, and to which they owe their com- 



muil contain a ■' ° , J 



fubftance which bulubility ; tor alter they have loft it, they unite to oxigen witn- 



they bfe in ou t exhibiting the phenomena of combuflion. 

 Protiv&tan. Though the produces of combuflion are not capable of fup- 



give oxigen to porting combuftion, they not unfrequently part with their oxi- 

 convert them in- S en J 11 ^ as ^ u PP or ^rs do, give it out to combuftibles, and con- 

 to products j but vert them into products ; but during this procefs no heat nor 

 they do not, hke jj i t j evolved. Water, for inftance, gives out its oxigen 



Jupporters, caule b , t ' b ° 



combuftion. to iron, and converts it into black oxide, a product ; and fulphu- 



ric acid gives out its oxigen to phofphorus, and converts it in- 

 to phofphoric acid. Thus we fee that the oxigen of produces is 

 capable of converting combuftibles into products, juft as the 

 The oxigen of oxigen of fupportcrs ; but during the combination of the laft 

 fupparters differs on ly are } iea ^ an( j liorht emitted. The oxigen of fupporters 



from that of , J ' .. r , . 6 ,., . . ,. 6 , o 



prcduBs. then contains lomething which the oxigen or products wants. 



Combuftibility g. Whenever the whole of the oxigen is abftracted from 

 produ&s on\\ by produces, the combuftibility of their bafe is reftored as com- 

 sbmbuflibki. pletely as before combuftion ; but no fubftance is capable of 

 abftracling the whole of the oxigen, except a combuftible or a 

 •partial combuftible . Water, for inftance, is a product of com- 

 buftion, whofe bafe is hidrogen. To'reftore the combuftibility 

 of the hidrogen, we have only to mix water with iron or zinc 

 tilings ; the metal is oxidated, and the hidrogen gas is evolved 

 as combuftible as ever. But no fubftance, except a combuf- 

 tible, is capable of feparating hidrogen gas from water by com- 

 bining with its oxigen. In the fame manner phofphorus abforbs 

 the oxigen from fulphuric acid, and is converted into a product, 

 while fulphur is feparated in its ufual ftate of combuftibility. 

 Thus we fee that combuftibles are capable of reftoring the 

 combuftibility of the bafes of produces, but they themfelves 

 lofe their combuftibility by the procefs, and are converted into 

 produces. Combuftibility, therefore, may be thrown at plea- 

 Doctrine of ^ Lire fr° m one k oc ty to another. This fact was firft fet in a 

 Scalii. proper light hy Stahl, and was the great ftep in the theory of*" 



combuftion 



