Jllmichestcr Memoirs, Vol. xliv. (1900), No. V\. 9 



any powerful draught was prevented from impinging 

 upon the flame, and rendering it unsteady. 



The rate of oxidation of the nitrogen, in this apparatus, 

 far exceeded that in the previous one. In an experiment 

 extending over 1 1 hours, 4876 grms. of nitric acid were 

 produced for a continuous expenditure of 227 watts. This 

 is equivalent to 180 grms. of nitric acid per horse-power 

 per 12 hours, or almost twice the quantity produced in the 

 first apparatus. 



A second experiment of the same duration, but in 

 which only 200 watts were consumed in the flame gave 

 5r9 grms. of nitric acid. This is equivalent to 210 grms. 

 per horse-power per 12 hours. 



A third experiment extending over 30^'^ hours, and 

 in which 227 watts were used in producing the flame gave 

 1 38' 1 6 grms. of nitric acid. 



This is equivalent to 180 grms. per horse-power per 

 12 hours. 



The relative efficiency of the three forms of " com- 

 bustion-chamber " is more easily seen by comparing the 

 results tabulated below. 



Succeeding experiments with this apparatus gave 

 results closely agreeing with the preceding, and from these 

 figures it would seem that the form of " combustion- 

 chamber " to be arrived at is one in which the oxides of 

 nitrogen should be removed from the influence of the 

 flame as quickly as possible, and in which convection 

 currents should be avoided. If these conditions are not 

 observed, the gaseous products of oxidation will be again 

 partly resolved into oxygen and nitrogen by the intense 

 heat of the flame, the temperature of which is about 

 2,000° C. The decomposition of both nitric oxide and 

 of the peroxide begins to take place at a red heat. 



The vessel finally assumed the form represented by 



