Researches on the Salts of Selenious Acid. 



53 



ordinary temperatures, does not consist at 100°, but ' loses, besides water, also 

 hydrochloric acid, on account of which the loss of weight, on drying in 

 warmth, considerably exceeds the amount of water in the >alt". As for the 

 oxalates 1 ), one of them, which after being dried at 100° had the composition 

 Be.0 2 .C 2 2 + Be.0 2 H 2 + H 2 0, requires a neutral salt permanent at this tem- 

 perature, such as Be.0 2 .C 2 2 -f-H 2 0, whereas the other, which under the same 

 circumstances had the composition: Be.0 2 .C 2 2 + GBe.O'.H 2 , makes it ne- 

 cessary to suppose another neutral oxalate at the same temperature, viz. 

 Be.0 2 .C 2 2 . The author remarks himself the latter contradiction but regards 

 this fact as deficiency ("felaktighet") rather than in consequence of it reject 

 a view, founded on too limited a number of not even concordant observa- 

 tions. The regularity in the aqueous contents ot the basic salts, which 

 he supposes himself to have observed, will accordingly not bear application 

 to the basie salts that he had himself examined, much less can it be made 

 the foundation of any theory of the constitution of basic salts in general. 



SELENITES OF MANGANESE. 



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



Was obtained by a double decomposition of sulphate of manganese 

 with diselenite of potassium. Then falls, at the ordinary temperature, a 

 colourless, insoluble, amorphous salt which, on heating the solution, imme- 

 diately, but at the ordinary temperatur, only gradually is converted to a 

 crystalline powder of microscopical, probably monoclinic prisms in combina- 

 tion with basal- and klinodiagonal end-faces and other forms. The cry- 

 stals have a slight tint of reddish-yellow. Berzelius has remarked the 

 peculiar deportment of this salt, when heated in a glass-tube; the glass is 

 namely eaten through, without assuming the slightest colour of manganese. 



Analyses: 



1) 0.833 gr. salt gave 0.2995 gr. selenium or 0.4208 gr. selenious acid, 

 and 0.297 gr. manganoso-mangauic oxide, after being precipitated as 

 carbonate and heated, or 0.2762 gr. manganous oxide. 



2) 0.8418 gr. salt gave 0.3 gr. selenium or 0.4215 gr. selenious acid, and 

 0.2781 gr. manganous oxide weighed as 0.299 gr. manganoso-manganic 

 oxide. 



') Loc. cit. p. 35. 



