ON OXYAMIDOSULPHOXATES. 913 



to be the only sulphoxyazotised acid possessing any stability. Claus 

 introduced the slight modification of Fremy's process for preparing 

 it of omitting the preliminary neutralisation with ammonia. 



Having discovered a second barium salt, neutral and soluble, we 

 proceed differently in treating the barium precipitate, and thereby 

 avoid the contamination of the salts with sulphite, always present in 

 Fremy's barium precipitate (see the section of this paper headed, the 

 decomposition of oxyamidosulphonates by alkaline bases). The dibarium 

 salt is, as found by Freiny. Aery alkaline to litmus, and we add to it 

 only enough sulphuric acid to get a neutral solution, along with 

 barium sulphate equivalent to half the barium and such barium sul- 

 phite insoluble as may have been present in it. The solution contains 

 only nionobarhun oxyamidosulphonate and from it can be prepared 

 the acid and its salts by adding its equivalent of sulphuric acid or a 

 sulphate, to determine which, an estimation of barium is made in a 

 portion of the solution. 



Raschig prepares an impure acid from Fremy's solution obtained 

 by boiling potassium oximidosulphonate so as to hydrolyse it into 

 potassium sulphate and oxyamidosulphonate. To do this he removes 

 the potassium sulphate by alcohol and then concentrates the solution 

 of the acid to a syrupy consistence. 



Sodium oxyanndosulphonate } prepared by Freuiy and by us, is a 

 clear gummy liquid as thick as molasses, which exposed over sul- 

 phuric acid (in a partial vacuum) never solidifies or shows any sign 

 of crystallisation. It is neutral in reaction. 



Potassium oxyamidosulphonate, prepared and analysed by Fremv. 

 by Claus, and by us. It occurs in six-sided plates as stated by 

 Fremy, when crystallised from its hot solution, but the plates are 

 more often square, while by spontaneous evaporation of its cold 

 solution thick tables and bold prisms are obtained. Clans found the 



