374- Experiments on Ammonia. 



gen vary essentially according to the proportion of the gases 

 which are employed. If the oxygen gas exceed consideia- 

 bily the ammonia (that is, if its volume be double or up- 

 wards) the ammonia entirely disappears, and no gases re- 

 main, but a mixture of nitrogen with the redundant oxy- 

 gen. The moment the detonation is completed, a dense 

 cloud appears*, and soon afterwards settles into a white 

 incrusti^tion on the inner surface of the tube. The quan- 

 tity of this substance which is produced is too minute for 

 analysis ; but its characters resemble those of nitrate of 

 ammonia, the acid ingredient of which is probably gene- 

 rated by the action of oxygen on the nitrogen of one part 

 of the volatile alkali. Accordingly, when the excess of 

 oxygen is removed by sulphuret of lime, the nitrogen ge- 

 nerally falls short of the proportion which ought to accrue 

 from a given weight of ammonia ; and hence it is scarcely 

 possible to attain, when a considerable excess of oxygen is 

 used, an accurate analysis of the volatile alkali. 



When, on the contrary, the ammonia exceeds consi- 

 derably the oxygen gas, no production of nitrous acid ap- 

 pears to take place; for the residue, after detonation, is 

 quite free from cloudiness. It is remarkable, however, 

 that ammonia when fired, in certain proportions, with less 

 oxygen than is required to saturate its combustible ingrer 

 dient, is nevertheless completely dfcomposed. Part of its 

 hydrogen is sufficient for the saturation of the oxygen ; and 

 the remaining hydrogen, and the whcle nitrogen of the am- 

 monia, together with that existing &s an impurity -in the 

 oxygen employed, remain in a gaseous state, and compose 

 a mixture, which may be inflamed by adding a second 

 quantity of oxygen gas, and passing an electric spark f- 

 In this way all the hydrogen of the volatile alkali may be 

 saturated with oxygen, and condensed into >vatcr; and the 

 whole of the nitrogen may be obtained as the final result of 

 the process. After determining the amount of the oxygen 

 consumed both in the first and second combustions, it is 



•In some cases I have observed, that when the cloud does not occur im- 

 mediately, it maybe made to appear by agitating the quicksilver contained 

 in the detonating tube. This is probably owing to the disengagement of 

 some ammonia, which had lodged in the mercury. The fact -coiifirms what 

 I have already suggested respecting the cause of the variable proportion of 

 gases evolved from .ammonia by electricity. 



•f- This is analogous to what happens when ether, alcohol, or any of the 

 rtcriform cor.ipoiiiids of carbon and hydrogen, are exploded %vith a deficient 

 proportion of oxygen ; for much of the hydrogen is found in the residuum 

 in tlie state of gas, and again becomes susceptible ot combustion after the 

 addition of a second quantity of oxygen. (See Mr. Cruickshank's excellent 

 papers in the filth volume «jf Nicholson's Jeurnal, -Uo.) 



easy 



