SODIUM OR POTASSIUM : EDWARD DIVERS. ■ 41 



edly determined. It can now, however, be stated with cer- 

 tainty that Menke's salt was not the sodium hyponitrite obtain- 

 able by reducing sodium nitrite by sodium amalgam and water, 

 for this difters from it in degree of hydration and stability and 

 in other properties. 



1). H. Jackson {Proc. Ch. Soc, 189))) described two ways 

 in Avliich he had succeeded in preparing sodium hyponitrite, 

 but with such difficulty as deterred him from investigating its 

 properties. Indeed, in proof of his success he mentioned only 

 that he had got crystals and that these contained the propor- 

 tion of sodium proper to the salt, and this happens to be no 

 proof at all. For, firstly, sodium carbonate has just the same 

 content of sodium, secondly, the hyponitrite is actually a 

 hydrated salt not to be rendered anhydrous without some 

 decomposition, and, thirdly, though of crystalline texture, the 

 salt can hardly be described correctly as occurring in crystals. 

 Nevertheless, his success in getting the salt is not to be 

 doubted. One of the methods he adopted was to reduce a con- 

 centrated solution of sodium nitrate by sodium amalgam, 

 evaporate the solution in a vacuum until the salt crystallises, 

 and wash the crystals with alcohol to free them from sodium 

 hydroxide. He found the evaporation to take several weeks 

 and the salt he obtained was very small in quantity. Such 

 should not have been his experience, even though he had taken 

 nitrate instead of nitrite for reduction and thus greatly increased 

 the quantity of sodium hydroxide, very large in any case. 

 With some modification, the process he followed is an excellent 

 one. 



To obtain sodium hyponitrite from its solution, prepared as 

 already described (p. 38), is a simple matter, but this solution, 



