METALLIC OXIDES. 241 



nevertheless, clear, that the success of an experiment of this 

 nature would be decisive as to the nature of ammonium. 



/. Concerning the Oxides of Antlmonium. 



Notwithstanding the labours of chemists have, perhaps, been On the mun- 

 more frequently employed upon this metal than upon any uer > & c «.°t 

 other, we have hitherto possessed but few data respecting the jdes. 

 number and the nature of its oxides j and the information 

 given in elementary works is often contradictory the one to the 

 other. Thechemists who have operated the most successfully 

 upon these oxides are, MM. Proust, Thenard, and Bucholz. 

 Thenard, guided by the principle of unlimited combinations 

 advanced by the illustrious Berthollet, found that antimony 

 produced six different oxides, that is to say, one black, one 

 chestnut brown, one greyish white and fusible, one white and 

 not fusible, one orange, and one yellow, in which the quantity ' 

 of oxigen differed no more than one or two per cent. Proust, 

 on the contrary, found no more than two oxides, of which he 

 has determined the composition with considerable accuracy j and 

 Bucholz, who repeated the experiments of Thenard with the 

 intention of examining them, could find only two degrees of 

 oxicjation precisely the same which Proust had described. I The auth 

 have found as many as four, which it is incontestibie that has found four. 

 Thenard saw, though he did not well distinguish them from 

 the mechanical mixtures of different degrees of oxidation, 

 which are very frequently obtained j and though he has given 

 no other distinctive character ihan the colour, which is so often 

 fallacious. 



I must observe, that the antimony employed in all my expe- Antimony was 

 periments was purified in the following manner : I reduced it purified by fu- 

 to powder, and mixed it with the white oxide of antimony, ^^ ! lls 

 which I ihen exposed to fire till the mixture was fused. If 

 the fused oxide, which flowed above the metallic bottom, was 

 found to be coloured after cooling, I repeated the same ope- 

 ration. 



1. Suboxidum stihicum is formed when the metal is exposed ± Suboxidum 

 for a long time to the action of an humid and warm atmos- stibicnm 1; 

 phere. It forms an extremely thin coat of a blackish grey atmosphere • 

 colour, which prevents all farther action of the atmosphere biackish grey, 

 upon the parts so covered. In order to obtain this suboxide in 



larger 



