FEEMy's SULPIIAZOÏISED SALTS OF POTASSIUM. 227 



under which they were obtained, — apparently because he was 

 not able to be more precise. When Claus attempted to get 

 Fremy's salts he obtained only masses of minute crystals of salts 

 of whose individuality and nature he could make out little be- 

 cause of the impossibility of dissolving them all up undecomposed. 

 In his experiments the ' sulphammonate ' (nitrilosulphate) was 

 always formed in considerable quantity eitlier as a first or second- 

 ary product and by its presence prevented any satisfactory inves- 

 tigation of the other salts. In Fremy's working, this most easily 

 formed salt came only as the final product of the sulphonation 

 and therefore gave him no trouble. Claus emphatically displayed 

 his scepticism as to Fremy's results ; yet in nearly every point 

 in which he difi'ered from Fremy as to the facts we find Fremy 

 to have been right. When Raschig repeated Fremy's work — 

 hut with the modifications in procedure introduced by Clans — he 

 got results similar to, though less unsatisfactory than, those Clans 

 had obtained. He made an approach to Fremy's work in so far as 

 that he often got very little nitrilosulphate ; nevertheless he too 

 failed in his attempts to prepare the ' sulphazate ' in Fremy's way. 



In perhaps all essential points we can lay down the method 

 to repeat Fremy's experimental work successfully. But in some 

 cases a little uncertainty obtains owing to the fact that the very con- 

 centrated and complex solutions which yield Fremy's salts are apt 

 to deposit what is virtually the same salt in different forms as well 

 as at times salts quite distinct from each other under only slight and 

 obscure variations in the circumstances attending their formation. 



Sulphazate. — This is Fremy's first salt directly obtained in 

 his sulphonation of the nitrite. In getting it he took approxi- 

 mately 5 mois, potassium nitrite to 2 mois, potassium hydroxide 

 and a little water and into the solution passed sulphur dioxide 



