Potassium nitrososulphate. 



By 

 Edward Divers, M.D., F.R.S., Prof., 



aud 



Tamemasa Haga, F.C.S. Rigakuhakushi, Asst. Prof. 



Imperial University. 



Hantzsch has recently expressed the opinion (Berichte, 27, 3264), 

 that there exist two potassium nitroxysnlphites, one being Pelouze's 

 nitrosulphate (the nitrososulphate of Henry Watts and of ourselves), 

 the other a salt obtained by Raschig (Annalen, 241, 230) and again 

 by himself. This opinion we cannot share lor reasons we proceed to 

 state. 



Above all, Hantzsch is mistaken in holding that Pelouze found 

 the nitrososulphates to be precipi table by barium salts. The latter 

 expressly states the contrary, in proof that these salts cannot be taken 

 to be sulphates, with nitrous oxide acting merely as water of crystalli- 

 sation. There is, indeed, a sentence in his paper calculated to mislead 

 on this point, wherein he says that the solution of the ' new salt ' 

 gives a precipitate with a barium salt, which, when washed, is soluble 

 in nitric acid. For this precipitate, as the context enables one to 

 make out, is only that caused by impurities, such as carbonate, in the 

 potassium hydroxide employed in the experiment then described, 

 which precipitate he desired to show to be free from sulphate, by its 

 solubility in acid. Thus, if our reading of Pelouze be correct, and it 



