IMIDOSÜLPHOXATES (2ND. PAPER). 197 



Sodium imidosulphonates. — That, contrary to Fremy's experience, 

 sodium nitrite can be sulphonated as easily as potassium nitrite was 

 ascertained by Raschig and by us about the same time, and later we 

 ourselves prepared the normal and two-thirds normal sodium salts, «as 

 well as some compound salts. Berglund, however, had prepared the 

 normal sodium salt and also the mercury sodium salt, but not by sul- 

 phonating sodium nitrite. He either boiled ammonium imidosulphonate 

 with sodium hydroxide till all ammonia had been expelled, or, more 

 satisfactorily, he precipitated by potassium chloride the two-thirds 

 normal potassium salt from the ammonium salt ; dissolved it in a 

 boiling solution of sodium hydroxide and chloride ; and then by cool- 

 ing crystallised out the normal sodium salt. His description of the 

 normal sodium salt, so far as it goes, agrees with ours. The crystal- 

 line salt which he sometimes got in place of the ordinary normal 

 sodium salt, and which he believed to be that salt in the anhydrous 

 state, we take to have been a double salt of normal sodium imidosul- 

 phonate and potassium chloride. 



He did not obtain the tw T o-thirds normal sodium imidosulphonate, 

 nor its compounds with ammonium nitrate and with potassium 

 nitrate, nor sodium ammonium imidosulphonate. 



Barium imidosulphonates. 



Berglund's account of normal barium imidosulphonate agrees with 

 ours, even to the detail that, like us, he once got it pure by a 

 first precipitation, but in all other instances found it necessary to free 

 the first precipitate from potassium or sodium, as the case might be, 

 by dissolving it in hydrochloric acid and reprecipitating it with baryta 

 (or barium chloride and ammonia). He was really the first to prepare 

 this salt and did himself injustice in crediting Woronin and Jacquelain 

 with its previous preparation. Woronin never analysed his product, 



