0XIMID0SULPHOXATE8 OR 8ULPHAZ0TATES. 33 



phonates evaporated togetlier. best in a vacuum desiccator, are con- 

 verted int<3 the less alkaline salt in crystals. Two equivalents of the 

 former combine with one of the latter, and this happens even when 

 only one equivalent of the former salt is taken, excess of the latter 

 then remaining in the mother-Hquor. We find also that, when a 

 concentrated solution of the more alkaline potassium salt is mixed 

 with a cold supersaturated solution of the neutral potassium salt 

 in equivalent quantity, crystallisation of the less alkaline salt soon 

 sets in, or else can be at once determined by adding a crystal of 

 this salt. 



Conversely, in a manner, as Fremy found, the less alkaline salt 

 is resolved, when treated with the solution of a lead or a barium salt, 

 into the neutral salt and the more alkaline salt, the latter becoming 

 bv the reaction an insoluble salt of lead or barium with potassium. 

 Indeed, this conversion is the basis of one of Fremy 's methods 

 of getting the neutral potassium salt. Fremy's observations were 

 emphatically discredited by Claus and ignored by Raschig. 



Weak acids— including sulphurous acid (cf. Fremy) — and even 

 strong acids diluted and cautiously used, convert the alkaline salts 

 into the neutral, when added not in excess so as to hydrolyse the 

 oximidosulphonate. Claus strongly denied this to be the case, but 

 Fremy was right. Metasulphites also, added not in excess, remove 

 alkali from the alkaline salts, they themselves becoming thereby 

 normal sulphites, as shown by tlie mixed solutions being neutral to 

 rosolic acid. 



Several metallic salts such as those of zinc and manganese Ijehave 

 like acids with the alkaline salts, converting them into the neutral 

 salts, and depositing their own metal as hydroxide, as was observed 

 by Fremy. Water alone when ])resent in large quantity suffices to 

 convert the more alkaline potassium salt into the less alkaline salt 



