ON OXYAMTDOSULPITOXATES. 223 



reaction of sulphurous acid with stannous chloride for its estimation. 

 Stannous chloride has no action upon hydroxyamine (Divers and 

 Haga, J. Ch. Soc. 47 624). and none upon oxyarnidosulphonic acid. 



Our procedure was to put in a pressure-bottle the diluted solution 

 of the salt decomposed by alkali and neutralised, mix it with excess of 

 stannous chloride, and almost fill the bottle with water. Some 

 nrsenious oxide was also added in order to fix all hydrogen sulphide 

 in presence of the necessary excess of hot acid, which was. however, 

 not so concentrated as to lead to reduction of arsenic by the tin-solu- 

 tion. The tightly closed bottle was kept in nearly boiling water for 

 an hour, and then left to cool. The washed precipitate of stannous 

 sulphide was heated with hydrochloric acid and potassium chlorate 

 until all sulphur had oxidised, and the solution evaporated to dryness, 

 and again evaporated with hydrochloric acid to dryness. Finally, 

 after removing the tin by hydrogen sulphide, the sulphuric acid in 

 the filtrate was estimated as barium salt. In this way, from 0.7470 

 gram of salt, which by long keeping had slightly hydrolysed, we got 

 sulphur equivalent to 88.63 per cent, of all in the original sulphonic 

 salt. Another sample, freshly crystallised, in fine plates, was boiled 

 with the potassium hydroxide, entirely out of contact with air, by 

 keeping it in an atmosphere of hydrogen. Thus treated, the product, 

 with the tube containing it, ? was dropped into the bottle of stannous 

 chloride. In this case, 0.2007 gram gave 89 % (89.05) of the sul- 

 phur as sulphite. These results render it clear that sulphite and 

 therefore hyponitrite are the two and only primary products of the 

 change. 



The reaction by which hyponitrite and sulphite are formed con- 

 sists probably in the substitution of the hydrogen of the oxyamiclo 

 radical by potassium, and then of self-decomposition of the potassium 

 compound. There is no hydrolysis or saponification, simply dis- 



