292 E. DIVERS AND T. HAGA : 



solution of pyrosLilpliite (and of ijormal sulphite, but of that we 

 treat in sect. III. b.) to nitrous fumes which act as nitrous an- 

 hydride when of the riglit composition. The gases were found 

 to be fully absorbed by a concentrated solution of potassium 

 pyrosulphite kept cold in a liask immersed in ice and brine and 

 well agitated. Soon an abundant precipitation began of hydrox- 

 imidosulphate mixed with a little nitrilosulphate. While still 

 much pyrosulphite remained, the process was stopped and the 

 mother-liquor at once drained olf. In this way we had great 

 success in getting much hydroximidosulphate and only a little 

 nitrilosulphate, notwithstanding the presence all along of so much 

 pyrosulphite ; for, as was [)ointed out by us long ago, in suffi- 

 ciently cold solutions sulphonation to nitrilosulphate hardly 

 occurs. 



The next five sections (III. b, c, d, e, f) treat of various 

 mixtures which, iioni the acid constitution of one of the com- 

 })onents, behave like that of nitrite and pyrosulphite, that is, as 

 if each contained pyrosulphite and nitrous acid. 



III. — b. JVormal Sulphite also all active upon Nitrous Acid. 



Keplacing the pyrosulphite used in the last experiment by 

 the normal sulphite, it was found that again but in this case 

 gradually, hydroximidosulphate precipitated, as well as very little 

 nitrilosulphate. But here potassium nitrite proved to be another 

 product, which by gradually replacing the potassium sulphite 

 in the solution allowed the process to be carried very far to- 

 wards completion. The reaction is expressed by the equation — 

 :3HNO, + 2K,S03 = 2KNO, + OH, + K,HNSA, ûom which it is 

 seen that only one-third of the nitrous acid becomes sulphonated, 

 the rest being used up simply as an acid. 



