52 



DIVERS AND HAGA. 



abundant precipitate with excess of baryta water, freely soluble in 

 nitric acid, exclusive of a little sulphate ; and particularly by its yield- 

 ing a crystalline precipitate, also aljundant, with potassium acetate. 

 'Tacquelain converted his ])reparation into the very soluble dibarium 

 salt l)v just neutralising- the acid with the Ijaryta, knowing, however, 

 that excess would give him the insoluble salt. Un leaving the solution 

 of the acid in a vacuum-desiccator it was found by us to have almost 

 wholly hydrolysed into amidosulphonic acid in eighteen hours or less. 



Fremy attempted to prepare the acid by adding hydrofiuosilicic 

 acid to j)otassium imidosulphonate and found it to decompose almost 

 immediately. He made out the products of its decomposition to be 

 sulphuric acid, sulphurous acid, and ammonia, but in this he must 

 have erred. J^erglund prepared the acid as Jacquelain had done, and 

 found it very unstable. 



We find that dry dijjotassium imid(jsulphonate may be mixed 

 with dry potassium hydrogen sulphate, and fused with it without 

 being affected. At temperatures high enough, 420°-450°, the 

 imidosulphonate suffers the decompijsition proper to it when alone. 

 To obser^'e the inactivity of the salts ordinary moist air has to be 

 excluded, and we therefore \\()rked in a Sprengel-pump vacuum. 

 From the fused mixtui-e of the two salts, cooled and powdered, alcc^hol 

 dissohes out only a very little sulphuric acid ; ether does the same. 



Dipotassium iniidosul])honate, in dry, tine powder, mixed with 

 two mc^lecular proportions of sulphuric acid, sp. gr. 1.84, forms a 

 thin jiaste, which kept in a dry atmosphere S(jon scjiidities to a hard, 

 somewhat translucent mass. Powdered and exposed to air, this mass 

 does not deliquesce. Left foi* days in dry air it experiences no evident 

 change. On dissolving such a preparation in water, to which a little 

 potassium hydroxide has been added to guard against much hydro- 

 lysis ol" any component, it yields much imidosulphonate unchanged, 



