NON-EXISTENCE OF AMIDOSELENITES. 209 



alcohol very soon causes ammonium selenites of varying com- 

 position to precipitate. We are thus brought in contact with 

 the experimental work of Cameron and Macallan {Proc. Roy. 

 Soc, 1888, 44, 112), who obtained just such a precipitation by 

 passing ammonia into a solution of selenion dioxide in absolute 

 alcohol, the ammonia being described as having been carefully 

 dried by passing it throngh a series of potash tubes. But the 

 examination they made of their product and of a derivative of 

 it led them to consider the two substances to be amidoselenites 

 or selenosamates, and not merely selenites. 



We have analysed and in other ways examined the products 

 we have obtained in this way. The crystalline precipitate in 

 presence of excess of ammonia is diammonium selenite and can 

 be rendered dry and anhydrous, without decomposing it, in a 

 potash desiccator, charged with a strongly ammoniacal atmos- 

 phere. It is a very alkaline and very deliquescent salt, 

 which yields half its ammonia when its aqueous solution is 

 distilled to a small volume. Exposed in a sulphuric-acid 

 desiccator for 20 or 30 hours, it also loses half its ammonia, 

 becoming the half-acid salt. Left for several months in such 

 a desiccator, occasionally opened, it becomes the three-fourths- 

 acid selenite. The results of the analyses of the three salts 

 were very satisfactory, and were obtained when, so to speak, we 

 did not know exactly what we were analysing. They are 

 given as parts per hundred, in the following table : — 



(NHASeOg: seien, diox., 68.09 



Found : „ 67.96 



(NH,)HSe03: „ 76.03 



Found : „ 76.01 



(NH4)H3(Se03)2: „ 80.73 



Found : „ 81.51 



ammonia, 20.87 



21.02 



11.64 



10.88 



6.18 



6.22 



