COMBUSTION OF AMMONIA. 



241 



vessel described elsewhere, 1 and which has already been used 

 by M. Ogier and the author for burning pure carbonic oxide, 

 acetylene, olefiant gas, benzene, cyanogen, phosphuretted, 

 arseniuretted and silicated hydrogen, for forming hydrochloric 

 acid gas, etc. It is shown in the subjoined figure. 



This reaction, when effected satisfactorily, produces only 

 nitrogen and water, in accordance with the equation 



2NH + 



3H 2 0. 



The greater part of the water is condensed in the combustion 

 tube, and the surplus upon the solid potash in two consecutive 

 U-shaped tubes. This surplus re- 

 presents a very small proportion 

 of the water formed, a proportion 

 corresponding to the normal 

 saturation with the vapour of 

 water of the gases set free. Its 

 gaseous form has been taken into 

 consideration in the calculations. 

 The weight of the water is fur- 

 nished by the variation in the 

 weight of the vessel (filled with 

 pure oxygen) and of the U-shaped 

 tubes. From this we deduct the 

 weight of the ammonia consumed, 

 27 grms. of water being furnished 

 by 17 grms. of ammonia. 



The combustion should take 

 place all at once and without 

 relighting, an operation which 

 necessitates the opening of the 

 vessel and involves losses of 

 watery vapour. If the condensed 

 water shows any signs of the 

 presence of the oxygen compounds 

 of nitrogen, the quantity does 

 not exceed some ten thousandths, 

 that is to say, it may be dis- 

 regarded. 



The combustion of the ammonia, moreover, is complete, for 

 no appreciable trace of it was found in the condensed water, and 

 a tube of pumice-stone and sulphuric acid placed as a test at the 

 end of the U-shaped tubes of solid potash, never increased in 

 weight in the experiments. 



These facts being stated, the following results were obtained 

 under constant pressure, at about 12 : 



1 " Essai de M&anique Chimique," torn. i. p. 246. 



Fig. 40. Combustion of ammoniacal 



