OXIMIDOSULPHONATES OR SULP H AZOTATES. 5p, 



alkali, was drained on the tile, and then washed with alcohol ; (h) was 

 got by recrystallising from w^ater an unwashed salt like the last. This 

 was the only time we succeeded in recrystallising the salt from w:iter 

 without addin«: fresh alkali. It will be seen that botli Rascliicr's 

 results and ours agree much better in composition with the foi-itinl;i 

 of an impure salt than with tliat for !i salt with linlf a moJecide of 

 water t<^ one molecule of oximidosulphonate, (A) and from such results 

 no deduction can be safely made as to the decree of hvdr;iiinii of tlie 

 pure salt. 



\Ye once ol)tîiined the normal potassium salt crystallised with 

 two molecules of water. The salt ])recipitated by adding excess of 

 potassium hydroxide, and drained on the tile, was redissolved in water 

 and precipitated by alcohol. In other trials in this way we got the 

 salt with only one molecule of water as above. Our analysis included 

 the estimation of the oximide radical as hydroxylamine : — 



Calc. Found. 



Potassium 34-17 34-10 



Sulphur 18-64 18-81 



Oximide residue 8*74 8-44 



Dipotassium salt, K2HNS207,2H20. — Besides the tw^o excellent 

 methods of preparing this salt from potassium nitrite it can idso be 

 obtained, sometimes conveniently, from the disodium salt by pre- 

 cipitating this with potassium chloride, and is then more certainly 

 free from nitrilosulphonate. The yield in this way can be made as 

 much as 80 per cent, of the equivalent of the quantity of disodium salt 

 taken. Fremy's method of preparing it pure from the alkaline live- 

 sixths potassium salt by precipitating this with zinc or lead or barium 

 salt thus leaving the dipotassium salt in solution, and which did him 

 o-ood service, is now onlv of interest as establishing- the two i)otassium 

 salts as salts of one and the same acid. 



