ö8 HYPONITRIÏES ; PKOPERTIES ANÎ) PllEPAllATIÜN BY 



sodium salt. Tlie two liquids are now violently shaken together 

 for ten minutes or so, when all hydroxylamine will have ])een 

 destroyed. That it is so may be ascertained by taking out a 

 drop of the solution and adding to it some water, a drop of 

 silver nitrate solution, and slight excess of dilute nitric acid, 

 after which the resulting solution should prove to be free from 

 the least black tint due to silver reduced by hydroxylamine. 

 No gas is liberated during the shaking, but a very strong odour 

 of ammonia is developed. A minute quantity of nitrite is still 

 present, remarkahle to say, to remove which altogether seems 

 almost impossible, but which can be so far reduced by an 

 houi''s shaking of the solution with the amalgam that a little 

 of the solution largely diluted and acidified does not blue potas- 

 sium iodide and starch until it has stood for about an hour. 



The solution may l)e separated from the amalgam by a 

 funnel and then be exposed in a dish for a night in a sulphu- 

 ric acid desiccator ; in the morning it will be free from 

 ammonia, and present itself as a virtually pure and stable, 

 concentrated solution of sodium hyponitrite and hydroxide. 



As here described, the preparation of a solution of sodium 

 hyponitrite ready for use is the same as that followed by me 

 in 1871, with one important addition and not taking account 

 of the fact that I then had to be^in with nitrate and reduce 

 it to nitrite by sodium, as the only convenient way to get the 

 latter salt pure enough. The addition I refer to is the new 

 method of removing the hydroxylamine from the hyponitrite. 

 AVhen silver hyponitrite is prepared from the crude solution, 

 the hydroxylamine gets destroyed l)y silver oxide, as I pointed 

 out iji the addendum to my first paper. Zorn, as an improve- 

 ment, introduced the use of mercuric oxide, on the ground that 



