244 EDWARD DIVERS AND TAMEMASA HAGA ; 



Effects of heating amidosulphonic acid and its salts. 



The acid. — The only statement yet made, concerning the effect of 

 heating amidosulphonic acid in the absence of water, is Berglund's 

 that, when the acid is rapidly and sufficiently raised in temperature, it 

 is decomposed, and that sulphur dioxide, nitrogen, water, and sulphuric 

 acid are produced. That statement is correct, though it is remarkable 

 that ammonia is not mentioned in it, since this, in combination, 

 always appears among the products. But much below the temperature 

 at which the acid passes into these products, it suffers a complete 

 che ical change. This occurs largely when the acid appears to melt, 

 that is at 205°. In a closely limited space, to which air has not free 

 access, it sustains no loss in half an hour, when heated to 220°, and 

 only about 1 per cent, when heated to 260°. Just above 260°, small 

 bubbles very slowly form in the liquid, but become reabsorbed if the 

 temperature is lowered ; they consist, almost certainly, of ammonia. 

 There is much expansion in the act of melting, for the unmelted 

 particles sink freely in the melted part. The liquid forms a vitreous 

 mass, on cooling, which contracts so much as to partly detach itself 

 from the glass, even cracking this when very thin. The vitreous 

 I »rod net is brittle, exceedingly deliquescent, and very soluble in water. 

 Kept dry, it shows no tendency, in several days, to crystallise, and 

 remains quite transparent. 



Although the vitreous mass, obtained by fusing the acid, must 

 have the same ultimate composition as the acid itself, it yet contains 

 very little of the acid left. The predominant substance found, when 

 the mass is dissolved in water, is ammonium hydrogen sulphate. 

 More than half the quantity of the acid, that has been fused, comes out 

 then as the acid sulphate, that is, has combined with the elements of 

 water. Such a result, as the effect of heat alone, is plainly impossible, 



