294 E. DIVEES AND T. HAGA : 



with its inhibitory effect upon sulphonation (sect. II. a). In 

 this change it still holds true that it is nitrous acid itself which 

 is sulphonated, the potassium leaving the nitrite to enter the 

 sulphonate radical, and being replaced by hydrogen. 



Claus held that there could be no difference between the 

 effect of submitting a nitrite to the action of a sulphite and that of 

 mixing it with a solution of hydroxide and then treating it with 

 sulphur dioxide. The contents of this section and section II, a 

 show that essential difference exists between the courses and 

 results of the two procedures. 



III. — d. Action of Carbon Dioxide and of an Acid Carbonate 

 upon Normal Sidphite and Nitrite. 



As would be expected, the gradual addition of one of the 

 stronger acids to a solution of normal sulphite and nitrite leads 

 to the formation of sulphazotised salts. But even carbon dioxide 

 and the acid carbonates of the alkalis are effective in exciting ac- 

 tion in a solution of these salts. Concei-ning the activity of 

 carbon dioxide there is nothing to add to what was published in 

 our first paper (J. Cli. Soc, 1887, 51, 061), that the gas is very 

 slowly absorbed by the mixed salts in solution though not by 

 either salt alone and at the mean temperature, and that sulph- 

 azotised salts are then produced. Normal carbonates of the alkalis 

 are inactive. 



It is known that nitrites are not decomposed by carbon 

 dioxide, and also that alkali carbonates are decomposed by 

 pyrosulphites as freely at the mean temperature as by sulphur 

 dioxide itself. Accordingly, we have found that [)0tassium or 

 sodium acid-carbonate dissolved along with excess of normal 



