232 EDWARD DIVERS AND TAMEMASA HAGA ; 



instability when, in purifying the acid, they only ventured to dissolve 

 it in slightly warm water. 



Crystals of the acid will lie for months in concentrated sulphuric 

 acid unchanged ; heated with it till dissolved, the acid undergoes 

 essentially the same change as when heated by itself. Berglund found 

 the acid not to be decomposed by boiling with potassium hydroxide ; 

 while, according to Raschig, alkalis seem to make the acid more 

 unstable. We find the decomposition caused by continuous boiling to 

 be very slight, and no greater than that in a solution of the neutra 

 potassium salt kept at the same temperature. Alkalis appear, therefore 

 to be inactive. A solution of the potassium salt along with potassium 

 hydroxide can be evaporated on the water bath, without the salt 

 suffering noticeable change. Were it otherwise, how could sulphamide, 

 boiled with alkali, produce amidosulphonate, half the nitrogen only 

 escaping as ammonia (Traube) ? 



Heated in ordinary damp air to 100°, amidosulphonic acid very 

 slowly fixes water, through hydrolysing, and becomes sticky on the 

 surface of its crystals. Krafft and Bourgeois found this change to 

 proceed freely at 130-140°. Berglund, on the contrary, found that 

 the acid does not change in this way until at 190° or above ; but the facts 

 observed by Berglund are such as occur without the intervention of 

 moisture, as will be made clear when the effects of heating the acid are 

 described. 



Amidosulphonic arid retards the precipitation of small quantities 

 of sulphuric acid by barium chloride, a fact that must be taken into 

 account when testing for the beginning of decomposition of the acid 

 itself. A cold saturated solution of amidosulphonic acid, containing 

 one part sulphuric acid in 10,000 water, gives no precipitate for some 

 minutes after barium chloride solution is shaken with it, and then only 

 slowly and sparingly, though in 20 hours precipitation seems to be 



