S//? WILLIAM SIEMENS, F.R.S. IOI 



instead of from the top, a much higher illuminating power was 

 obtained. 



Operating on Staffordshire coal, which, in the ordinary way, 

 yielded gas of about 10 candle-power, he had obtained, by this 

 method, an illuminating power of eighteen candles, or twenty 

 candles. Very little tar, or other secondary products were formed 

 because, in passing over the heated surfaces, they were decomposed 

 and turned into gas, or combined with the coke, which latter was 

 thereby increased in hardness. It might be considered a drawback 

 that there were no secondary products, but it was in reality not 

 BO ; for in most places the tar and ammoniacal liquor were difficult 

 to dispose of, and if used to improve the coke they were applied to 

 the best advantage. 



He thought the question of coke making had oeen treated too 

 lightly. The present tendency of engineers was to burn coal in 

 locomotive engines, because coking, as generally performed, was 

 a wasteful process, in which the mosfi valuable part of the fuel 

 was lost. But by improving the coke ovens, and by making 

 judicious use of the gases, both for illuminating and heating 

 purposes, coke might be produced at a reduced rate, to be used for 

 locomotive engines and blast-furnaces, and a larger aggregate 

 saving of coal might be effected. 



In the discussion of the Paper 



" ON GIFFARD'S INJECTOR," 

 By JOHN ENGLAND, M. Inst. C.E., 



MR. C. "VV. SIEMENS* said he thought that the cause of action of 

 this instrument should be better understood than it appeared to be, 

 on account of the physical principles involved, which were, without 

 necessity, at present invested with mystery. He could not agree 

 in the view, expressed by Mr. Phipps, that the action of the 

 Injector was due to the circumstance, that the impact produced 



* Excerpt Minutes of Proceedings of the Institution of Civil Engineers, Vol. 

 XXIV. Session, 1864-65, pp. 222-225, and 236-238. 



