ACIDIFIABLE COMBUSTIBLES. 



Foiled in all these attempts, it would have 

 been requisite in order to determine the atomic 

 weight of this acid, to have had recourse to the 

 direct analysis of some of the seleniates. But, 

 besides that my stock of acid was exhausted, I 

 had no reason to expect more accurate results 

 from such an analysis, than those already ob- 

 tained by Berzelius. 



Upon the whole, I have little hesitation in 

 fixing upon 7 as the true atomic weight of this 

 acid. 



^* ^ e ex P er i men t s m ade by Berzelius on se- 

 lenietted hydrogen gas, will enable us easily to 



hydrogen. . 



determine the atomic weight or selenium, from 

 which the composition of selenic acid may be 

 directly deduced. 



This gas is colourless, has a smell somewhat 

 similar to that of sulphuretted hydrogen gas, is 

 very soluble in water, reddens vegetable blues, 

 and precipitates metals from their solutions. To 

 ascertain its constituents, Berzelius passed a 

 current of it through a solution of acetate of 

 silver ; seleniet of silver was precipitated, which 

 weighed when dry 1*888 parts. This seleniet 

 he dissolved in nitric acid, and threw the solu- 

 tion, while boiling hot, into muriatic acid. By 

 this contrivance, the seleniet was decomposed, 

 and the silver thrown down in the state of chlo- 

 ride of silver. The chloride thus obtained, 

 weighed 1-844. Now, chloride of silver is a 



