REMARKS ON COMBUSTION. 15 



though they cannot be made to burn in air except at a very 

 high temperature. Thus alfo oils burn rapidly when mixed 

 with nitrous acid. Nitrous gas and the gafeous oxide of azote 

 conftitute exceptions to this rule. 



4. None of the products of combuftion are combuftible &c- Produ&s of corn- 

 cording to the definition of combuftion which I have given, h ^£££™" 

 This want of combuftibility is not owing to their being fatu- 

 rated with oxigen ; for feveral of them are capable of combin- 

 ing^ with an additional dole of it. But during this combination 

 no caloric nor light is ever emitted; and the compound form- Oxygenation of a 



ed differs eflentially from a produa of combuftion ; for by this/"?^<* c0 » verts 

 ' r . J it into afupporter. 



additional dofe of oxigen the product is converted into afup- 

 porter. 



Hence we fee that combuftion ought not to be confounded Difference be- 

 with the combination of a body with oxigen, as is done by the t j onam j xige- 

 Frenchchemifts. Combuftion indeed cannot take place with- nation, 

 out the combination of oxigen ; but oxigen may combine with- 

 out combuftion. Thus when iron is burnt, it always combines 

 with 0.27 of oxigen, and is converted into (he black oxide, a 

 product of combuftion, and altogether incombuftible ; capable, 

 however, of combining with an additional dofe of oxigen, and 

 of being converted into the red oxide. But during this laft 

 combination, how rapidly foever it takes place, no heat nor 

 light is emitted. Now the red oxide of iron is not a product of Detonation of ^ 

 combuftion, but a fupporter ; as the following experiments de- \^^ ofironT 1 

 monftrate : Mix it with phofphorous, and put the mixture into 

 the bottom of a long glafs tube, fhut at one end, and filled with 

 azotic gas. Clofe the mouth of the tube, and apply heat to 

 that part in which the mixture is. At a certain temperature a 

 violent detonation takes place, which (hatters the tube in 

 pieces. It is needlefs to remark, that the tube muft be fuffi- 

 ciently long to prevent the effects of expanfton in the gas in- 

 cluded. 



When antimony is burnt, it always combines with 0.20 of Other product 

 oxigen, and is converted into the white oxide. Now this white / .,.. n ., f . i , mto 



o * ^ Jupporteri. 



oxide, which is a product of combuftion, and of courfe incom- 

 buftible, is capable of combining with an additional dofe of ox- 

 igen, and of being converted into the acidulous oxide of anti- 

 mony. In like manner, lead, when burnt, is converted into 

 the white oxide of lead, a product j but this product combines 



with 



