SELENIUM. 223 



Selenic acid 0-834-3 or 6-9782 

 Barytes 1-165? - 9*75 



2-0000 



171 parts of anhydrous biseleniate of barytes 

 treated in the same way, yielded 785 parts of 

 sulphate of barytes, equivalent to 518-9 parts of 

 barytes. Hence, biseleniate is composed of 



Selenic acid 752-1 or 14-132 

 Barytes 518-9 - 9*75 



1271-0* 



According to the result of the analysis of sele- 

 niate of barytes, the atomic weight of selenic acid 

 is 6*9782 ; according to the analysis of the bise- 

 leniate, it is 7'066. 



Though these results do not accurately corres- 

 pond with each other, they, upon the whole, 

 concur in rendering it very probable that the 

 true atomic weight of selenic acid is 7 I con* 

 sider the analysis of seleniate of barytes as sus- 

 ceptible of greater precision than that of the 

 analysis of seleniate of soda. Now, the atomic 

 weight of selenic acid, deduced from the mean 

 of the analysis of seleniate and biseleniate of 

 barytes, is 7*02211, which comes extremely near 

 to 7- 



T . n 1 Attempts 



2. 1 may state here a few attempts which I to deter. 

 made to determine the atomic weight of selenic 



lenic acid. 

 * Ann, de Chim. et de Phys. IX. 262. 



