METALLIC OXIDES. 945 



gen as the preceding degree, though the exact number was not 

 ascertained. 



In order to obtain a more determinate result by another pro- Exp. The ox- 

 cess, I endeavoured to reduce the white oxide at the first degree l fc a ° ec ^s " 

 of oxidation by means of metallic antimony. I, therefore, mixed heated with 

 the metal in extremely fine powder, with less of the oxide Jjj^ w^com- 

 than would have been required to oxide the metal. I intro- bination was 

 duced the mixture into a small phial, of which I drew out fus,t>le > &c - 

 the neck into the form of a capillary tube. The body was 

 bedded in sand in a small crucible, and exposed to a sufficiently 

 strong fire to make it red-hot j and, at the moment when the 

 matter entered into fusion, I hermetically closed the end of 

 the capillary neck, by melting the extremity, and I left the 

 mixture in that heat for half an hour. Three grammes of the 

 white oxide of antimony had oxided 0*323 grs. of metallic an- 

 timony, and afforded a fusible oxide. I reduced this again to 

 powder, and mixed it with powdered antimony, after which 

 I fused it in a similar phial - y but in its present state it was ca- 

 pable of dissolving only a small quantity of antimony, which 

 would have been correspondent with 003 grs. of antimony 

 upon the whole quantity of oxide. The fused oxide w r hich I 

 had obtained by this operation, was of a pearl colour, its frac- 

 ture crystalline, granulated, and very compact j it was ex- 

 tremely coherent, and difficult to break, and all its external 

 properties proved that it was not a pure stibious oxide. I re- 

 peated this experiment several times, and always found that 

 the white oxide, fused with metallic antimony, dissolved one- 

 third morethan it before contained j that is to say, that 100 l CO parts ox- 

 parts of the oxide can oxide an addition of 26 parts of the l^mor^of^ 

 metal; and if we attend to this result, which is determined metal, 

 with the utmost possible accuracy, we shall find that the fusible 

 oxide produced, of which the external characters are so difFe- 

 ent from those of the oxidum stibiosum, cannot be the same 

 as this last ; but that it must be a combination of the oxidum forming a 

 stibiosum with the white oxide in such proportion that the oxi- compound of 

 gen of the former is double that of the latter. Such combina- xides S of C <iif 

 tions between oxides of different degrees of the same metal, ferent de- 

 are not very rare, though they have not hitherto been much giee *' 

 attended to, or else have been considered as different degrees 

 of oxidation of the metal. I reduced the oxide into powder, 



" and 



