AMIDOSULPHONIC ACID. 245 



mid must, therefore, be in part, at least, due to the action of water in 

 dissolving the mass. This can easily be shown to be the fact, but in 

 doing so, it becomes established that nearly half the acid is actually 

 converted into sulphate, by heat alone. For, when the mass is dis- 

 solved in a solution of potassium hydroxide, sulphuric acid and 

 ammonia are still the principal products. But the proportion of the 

 former is now not so great as before. In the alkaline solution, and 

 sometimes separating out from it in crystals, there is present another 

 product in large quantity, which is imidosulphonate. Since the 

 quantity of ammonia is the same, whether the mass is dissolved in 

 presence of potassium hydroxide or in its absence, and since it is too 

 large to make only its acid sulphate with the sulphuric acid present in 

 the alkaline solution, it follows that some of the ammonia must exist 

 in the vitreous mass as aTnmonium imidosulphonate. The composition 

 of the alkaline solution at once explains how more sulphuric acid is 

 got by dissolving the product in the absence of alkali than in its 

 presence ; for acid imidosulphonate very rapidly hydrolyses into 

 sulphate and arnidosul phonic acid. ^Accordingly, it is found that 

 what, in the acid solution, is not ammonium hydrogen sulphate is 

 amidosulphonic acid itself; while, in the alkaline solution, so much of 

 the sulphur may he present as sulphate and imidosulphonate as to 

 leave only a little to be accounted for as amidosulphonic acid, also 

 present. It is now evident, since water from without does not enter, 

 that, in the production of ammonium sulphate by heat alone, one part 

 of the acid must yield the elements of water to the other part, and 

 remain itself as imidosulphonate, for nothing escapes during the heat- 

 ing. This is only possible by both sulphate and imidosulphonate 

 coming into existence as their pyro-salts, neither of them a yet known 

 salt or isolahle from the vitreous mass. But there is nothing to be 

 said against this assumption ; and the analytical dat «point, without 



