ALKALI METAL ; EDWAKD DIVERS. 23 



of a reduction when the temperature is kept tolerahly uniform. 

 De Wilde found that dilute solutions of nitrite or nitrate of 

 sodium or potassium gave larger quantities of nitrous oxide in 

 proportion to nitrogen when the solutions w^re dilute than 

 when they were concentrated, from which it mio-ht seem that 

 strength of solution does affect the proportions of the gases to 

 each other ; hut in the experiments conducted hy de Wilde, the 

 much greater rise of temperature when concentrated solutions 

 are acted upon fully accounts for the results he obtained. 



Ammonia can always be detected from the beginning of 

 the reduction (Thum thought not), l)ut its amount may be 

 minute throughout. It can be got in considerable quantity by 

 using a cold dilute solution, as for producing hydroxylamine, 

 and, after tlie main action is over, shaking it with amalgam in 

 a stoppered bottle until all hydroxylamine has disappeared. It 

 can also be got somewhat concentrated for a short time by drop- 

 ping the concentrated solution of the nitrite upon much solid 

 sodium amalgam, as was first observed by de Wilde ; but even 

 then much hyponitrite is still produced. Very hot and dilute 

 solutions of nitrite treated with sodium amalgam give little else 

 than ammonia and nitrooen. 



o 



The reduction of potassium nitrite by potassium amalgam 

 is closely like that of the sodium salt by sodium amalgam, in 

 all respects, quantitatively as well as qualitatively. 



If, for the moment, nitrogen and hydroxylamine be dis- 

 regarded, as they well may l)e, since their proportions become 

 very small under suitable circumstances, the nitrite may then 

 be said to be reduced simply to hyponitrite and much of this 

 to be hydrolysed into nitrous oxide and sodium hydroxide. 

 This at one time I supposed to be the case, and other chemists 



