236 ACIDIFIABLE COMBUSTIBLES. 



state by multiplying its atomic weight by 0-5555. 

 Now, 4-875 x 0-5555 = 2-7083 = specific gra- 

 vity of arsenietted hydrogen gas. 



The specific gravity of arsenic vapour ought 

 to be 2-6388. 



One volume of arsenietted hydrogen gas will 

 require for complete combustion, either 1-5 vol- 

 ume, or two volumes of oxygen gas. In the first 

 case, water and arsenious acid, and in the second 

 case, water and arsenic acid will be formed. 



SECT. VIII. 



OF THE ATOMIC WEIGHT OF TELLURIUM. 



THE atomic weights of all the acidifiable com- 

 bustibles have now been investigated, except of 

 tellurium, which is so scarce a substance, that I 

 have never had it in my power to make any ex- 

 periments upon it. But Berzelius has deter- 

 mined the composition of its oxide with his 

 usual accuracy. We may therefore take advan- 

 tage of his experiments to complete the series of 

 the atomic weights of all the simple acidifiable 

 combustibles. 



According to Berzelius, tellurium unites with 

 only one dose of oxygen, and forms an oxide 

 which has the curious property of forming neu- 

 tral salts, both with oxides and acids so that 



