54 



L. F. Nilson, 



Calculated on 100 parts: 



found calculated 



1. 2. 



Manganous oxide . . 33.16 33.03 MnO 71 32.57 



Selenious acid .... 50.52 50.08 SeO 2 111 50.91 



Water (loss) 16.32 16.89 2H 2 __36 16.52 



100.00 100.00 ~218 100.00 



Muspratt has undertaken a selenium determination of this salt, by 

 melting with nitre and weighing- the selenic acid formed as salt of barium, 

 the only instance in which selenious acid has been quantitatively deter- 

 mined by him. 



2. Neutral: Mn.0 2 .SeO+H 2 0. 



By mixing the neutral solution of sulphate of manganese with sele- 

 nite of potassium, there is also formed a white, amorphous, voluminous, 

 insoluble precipitate, which being left under the liquor, after the lapse of 

 some time diminishes, assuming a crystalline form. It then consisted of 

 microscopic four-sided tablets of a slight yellowish-red colour. 



Analyses: 



1) 0.519 gr. salt gave 0.2011 gr. selenium or 0.2826 gr. selenious acid and 

 0.3935 gr. sulphate of manganese, containing 0.185 gr. mauganous oxide. 



2) 0.5005 gr- salt gave 0.1932 gr. selenium or 0.2715 gr. selenious acid 

 0.3785 gr. sulphate of manganese = 0.1779 gr. manganous oxide. 



3) 0.3755 gr. salt, fumed with sulphuric acid, gave 0.282 gr. sulphate of 

 manganese or 0.1326 gr. manganous oxide. 



Calculated on 100 parts: 



experiment theory 



1. 2. 3. 



Manganous oxide. . 35.65 35.54 35.31 MnO 71 35.50 



Selenious acid . . . 54.45 54.25 — SeO 2 111 55.50 



Water (loss) . . . . 9.90 10-21 — H 2 _J18 9.0 



100.00 100.00 200 100.00 



It is worth notice that this salt, which is deposited from a comple- 

 tely neutral solution, holds less water of crystallization than the preceding, 

 which was precipitated with diselenite at the same temperature. 



