222 ACIDIFIABLE COMBUSTIBLES. 



Selenicacid 64-44 or 7'25 

 Soda 35-55 - 4 



100 



100 parts of biselejiiate (anhydrous, but deprived 

 also of a little of the acid) when treated in the 

 same way, yielded 41 parts of common salt, 

 equivalent to 22*22 parts of soda.* Hence, the 

 constituents of the salt are 



Selenic acid 77-77 or 14 

 Soda 22-22 - 4 



100 18 



It is obvious that the first of these two salts 

 contains one atom, and the second two atoms of 

 selenic acid, united to an atom of soda. But 

 the atomic weight of selenic acid resulting from 

 the two analyses does not quite agree ; accord- 

 ing to the first analysis it is 7*&5 ; according to 

 the second 7. 



(2.) Seleniate of barvtes is insoluble in water, 



ate of ba , . . * . 



rytes. and can only be obtained in the state or a white 

 powder. But biseleniate of barytes is soluble, 

 and probably contains water of crystallization. 



Two parts of anhydrous seleniate of barytes 

 dissolved in muriatic acid, and precipitated by 

 sulphuric acid, furnished 1 -76*5 parts of sulphate 

 of barytes equivalent to 1-1657 parts barytes. 

 Hence, the salt is composed of 



* Ann. de Chim. et de Phys. IX. 258. 

 16 



