REMARKS ON COMBUSTION. 23 



fome one or other of the fupporters be preterit. Whenever 

 they are excluded the procefs flops. All the fnpporters 

 known at prefent are the following fix : 



1 . Oxigen gas, 4. Nitrous gas *, 



2. Air, 5. Nitric acid, 



3. Gafeous oxide of azote, 6. Oximuriatic acid. 

 There are indeed certain fubftances befides thefe, which 



poflefs nearly the fame properties ; thefe I flia.Il enumerate 

 afterwards under the title of partial fnpporters. 



All the fupporters contain one common principle, namely, univerfally con- 

 oxigen. The firft of them confifts of oxigen uncombined with tam 0X1 S cn » 

 any bafe ; but in the other five the oxigen is united to a bafe. 

 It is very remarkable, that in four cafes out of five, the bafe 

 to which the oxigen in thefe compound fnpporters is united 

 is azote. Is it not probable from analogy, that oximuriatic N. B. 

 acid, the remaining compound fupporter, contains azote like- 

 wife as a component part. 



III. The incombuftibk bodies are neither capable of under- in. Incombufti- 

 going combuftion themfelves, nor of fupporting the combuf-^ 

 tion of thofe bodies that are; of courfe they are not imme- 

 diately connected with combuftion. At prefent we are ac- 

 quainted with about 13 incombuftible bodies, not reckoning 

 the compounds which they are capable of forming with each 

 other. Thefe are, 



1. Azotic gas, 3. The earths. 



2. The fixed alkalies, 



The firft: of thefe fubftances conftitutes the bafe of almoil 

 all the compound fupporters. Some of the alkalies and earths 

 poflefs certain properties in common with combuftibles, and 

 are capable of exhibiting phenomena fomewhat analogous to 

 combuftion ; phenomena to be defcribed afterwards under theSemi-combuf- 

 title of femi-combiiftion. tion * 



3. From the preceding obfervations it is obvious, that in Combuftion re- 

 every cafe of combuftion there muft be prefent a combuftiblc^™ & f om f >u f~ 



i -kt i ' i r>' 1 iomii twie and a jup- 



and a fupporter. Now during combuftion the combuitible 2\-p rUr , 

 ways unites with the oxigen of the fupporter. It is this com- 

 bination which occafions the apparent wafte and alteration of 

 the combuftiDle. The new compound thus formed I fhall call 



a product of eombuflioji. Now every product of combuftion is p ro du<3 of com- 

 buftion is either 



* Mr. Davy firft proved that this gas is a fupporter. aawalffic 



either, ox ;j e . 



