Manchester Mciuoirs, Vol. xliv. (1900), No. 13. 13 



51-5 per cent of the amount theoretically obtainable from 

 the amount of air passed in. 



This result favourably compares with that obtained 

 by Lord Rayleigh, who, working with a mixture of oxygen 

 and nitrogen in the proportion of two volumes of the 

 former to one of the latter, produced 440 grms of nitric 

 acid in the same time with the same amount of power. 



When air alone is used to supply the flame, the theo- 

 retical proportions of nitrogen and oxygen are diluted 

 with 2^3 times their volume of nitrogen. This, of course, 

 will exert a retarding effect upon the rate of oxidation of 

 the nitrogen. 



An experiment was conducted with a mixture of 

 oxygen and nitrogen in the proportion of two to one. The 

 gaseous mixture was passed through the apparatus at the 

 usual rate. A quantity of acid, almost double that pre- 

 viously obtained, amounting to 590 grms., was produced. 



To still further study the effect of temperature upon 

 the process of oxidation, the air before passing into the 

 burner was raised to a considerable temperature. For this 

 purpose, a porcelain tube, 13 mm. in diameter and 305 mm. 

 in length, was packed with asbestos, around which, and 

 interlacing with it, was a thick platinum wire. On passing 

 a sufficiently powerful current of electricity through the 

 wire, the whole tube was raised to incandescence, and the 

 air, after circulation through the heated asbestos, was 

 raised to a considerable temperature. The tube was 

 cemented into the air-inlet of the combustion-chamber. 

 With the flame operating in this apparatus, an experiment 

 extending over eight hours, in which 182 watts were used, 

 showed a decrease in the yield of nitric acid. Only 

 35'I2 grms. were produced. This is equivalent to 217 grms. 

 per horse-power per 12 hours. 



Two more experiments were made, under similar 



