ALKALI METAL ; EDWARD DIVERS. 21 



tion of the solution of nitrite or, to put it better the relative 

 quantity of water present, exercises most influence ; the only 

 other circumstance aöecting the course of the reduction is the 

 temperature at which it is allowed to proceed. The concentra- 

 tion of the sodium in the amalgam and the proportions of the 

 sodium and the nitrite are without direct effect on the reduc- 

 tion. Working with a sufliciently concentrated solution of 

 nitrite, the proportions of the products remain constant through- 

 out the reduction of the nitrite. Probably, this is the case also 

 when an exceedingly dilute solution of nitrite is used, but with 

 a somewhat dilute solution, say one in 30, there is some differ- 

 ence, due to the facts that the presence or absence of much 

 sodium hydroxide modifies the proportion of the products, and 

 that this substance is generated so largely. A dilute solution 

 of sodium nitrite may be made to behave as a concentrated 

 solution in the mode of its reduction by nearly saturating it 

 with sodium hydroxide before bringing it in contact with the 

 sodium amalgam. The addition of sodium hydroxide to a con- 

 centrated solution of nitrite before reducing it by sodium amal- 

 gam has no sensible effect, for the reason, no doubt, that in the 

 reduction of the nitrite, as it actually occurs, about 3.r niol. 

 sodium hydroxide are produced for one mol. nitrite reduced ; 

 quite enough therefore of itself to make the water of a concen- 

 trated solution almost proof against the action of sodium. With 

 a large quantity of water present, the sodium hydroxide formed 

 is not enough to render the water inactive, and in this is to be 

 found the explanation of the great difference observed in the 

 proportions of the products, according as the nitrite is dissolved 

 in much or little water. 



In order to produce as much hyponitrite as possible little 



