S/A' WILLIAM SIEMENS, F.R.S. 99 



In Hie discussion of the Paper 



"OX THE DISTILLATION OF COAL, THE UTILIZA- 

 TION OF THE RESULTING PRODUCTS, AND THE 

 MANQFACTURE OF COKE," by M. PERNOLET,* 



MR. C. W. SIEMENS said he had lately paid considerable attention 

 to the subject of coke-making ; and he believed that the coke-ovens 

 generally used, especially in the north of England, were very 

 primitive. The admission of air into them caused a portion of 

 the coke to burn, and the gases from the remaining coal, being 

 driven out, went to waste. He thought it hardly possible to 

 conceive anything more rude than that system, because those 

 gases, possessing heating powers of nearly equal value to the 

 remaining coke, were allowed to escape freely into the atmosphere, 

 involving not only a great loss of fuel in the most valuable form, 

 but also a serious nuisance in populous districts. As regarded the 

 quality of the coke produced in the ordinary oven, it had been 

 satisfactorily proved to be inferior to that produced in the close 

 oven when properly arranged, although it was, perhaps, more 

 lustrous in appearance. The reason of its real inferiority was, 

 that the coke first acted upon by atmospheric air was partially 

 burned ; but the carbonic acid formed by this combustion passed 

 through the remaining mass in the oven, and robbed it of such an 

 amount of carbon as was necessary to reduce the carbonic acid to 

 carbonic oxide. Hence the earthy constituent of the coke was 

 relatively increased, and, as was stated in the paper, the coke pro- 

 duced in close ovens contained, for the same amount of earthy matter 

 present, 1 5 per cent, pure carbon. This, with a poor description of 

 coal, was a most important feature, irrespective of the value of the 

 additional yield, both of coke and of the secondary products. 



As regarded the conversion of the ordinary coke-oven into a 

 close oven which he understood to be the subject of this paper 

 he considered that it was practicable, and that the kind of oven 

 now brought before the notice of the Institution, had many ex- 



* Excerpt Minutes of Proceedings of the Institution of Civil Engineers, Yol 

 XXIII., Session 1863-64, pp. 452-3. 



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