J6 KEMARKS ON COMBUSTION. 



with additional dofes of oxigen, and is converted into the red 

 Thfyaftbypartand bron-n oxides, both of which are fupporters. When the 

 of their oxigen j f u pp 0rierS} thus formed by the combination ofoxigen with pro- 

 duds, are made to fupport combuftion, they do not lofe all their 

 oxigen, bat only the additional dole which conftituted them 

 fupporters. Of courie they are again reduced to their original 

 ilate of produ&s of combuftion. Hence it follows, that they 

 owe their properties as fupporters, not to the whole of the 

 oxigen which they contain, but to the additional dofe which 

 conftituted them fupporters. We may therefore call them pen - 

 tied fupporters, indicating by the term, that part only of their 

 oxigen is capable of fupporting combuftion, and not the whole. 

 It is very poffible that both azote and muriatic acid may be pro- 

 ducts of combuftion; and in that cafe both the compound and 

 partial fupporters would agree with each other in every re- 

 fpect. In the prefent ftate of our knowledge, however, it is 

 neceflary to diftinguifti them. 



All the partial fupporters with which we are acquainted, 



and are partial 

 fpp.rters. 



The bafes of all 

 known partial 

 fupporters are 



metallic. 



Enumeration. 



contain a metallic bafts ; for metallic oxides are the only pro- 

 ducts at prefent known capable of combining with an addi- 

 tional dofe of oxigen. It is a circumftance highly deferving 

 of attention, that when metals are capable of combining with 

 ieveral dofes of oxigen, the product or oxide formed by com- 

 buftion is feldom or never that which contains a maximum of 

 oxigen. The following oxides are products of combuftion : 



8. Oxide of copper *. 



9. Oxide of cobalt*. 



1 0. Oxide of nickel *. 



11. Oxide of bifmuth*. 



12. Purple oxide of gold ? 

 I; 3. Yellow oxide of filver? 

 1 k Black oxide of mercury f? 



1. Black oxide of iron. 



2. White oxide of zinc. 



3. White oxide of lead. 



4. Yellow oxide of tin. 



5. White oxide of antimony. 



6. White oxide of arfenic. 



7. White oxide of manganefe. 



* The particular oxide of thefe metals, which is the product of 

 combuftion, has not been aicertained j but they are ail combuftiblc 

 in oximuriaric acid gas. 



f I doubt much whether gold, filver, and mercury, be combuf- 

 tible at all. They do not burn in air, how high foever the tem- 

 perature is } neither do they detonate with red hot nitre, nor exhibit 

 any appearance of combuftion in oximuriatic acid gas ; though this 

 laft body oxidates them with great rabidity. 



Th« 



