276 THE SCIENTIFIC PAPERS OF 



and the coke would be consumed in the furnace to greater advan- 

 tage. This could be accomplished by a blast of high temperature ; 

 and in this respect his opinion differed very much from the theory 

 of Mr. Bell, to the effect that there was a theoretical as well as a 

 practical limit to the beneficial heat of hot blast. He believed, on 

 the contrary, the blast could not be made too hot for economical 

 purposes, and that real progress in iron smelting must henceforth 

 be looked for chiefly in that direction. 



In the discussion of the Paper 



" ON THE CONDITIONS WHICH FAVOUR, AND THOSE 



WHICH LIMIT, THE ECONOMY OF FUEL IN THE 



BLAST FURNACE FOR SMELTING IRON," 



By ISAAC LOWTHIAN BELL, Assoc. Inst. C. E., 



MR. SIEMENS* said that Mr. Bell had watched blast furnaces 

 more carefully than almost any other metallurgist. Some of the 

 facts brought out in this paper were extremely interesting ; 

 amongst others the proof that the reduction of iron ore was a 

 source of heat instead of, as was more generally supposed, the 

 cause of loss of heat ; and that reduction was effected at so low a 

 temperature as 420 Fahr. Mr. Bell had endeavoured to show 

 that in the blast furnace the different operations, constituting the 

 process of smelting, might be carried on in such a way as virtually 

 to complete one process before the other commenced ; and from 

 this the somewhat astounding conclusion was arrived at, that 

 nearly all the advantages derived from the hot-air blast might be 

 realised by simply increasing the size of the furnaces. The argu- 

 ment was not pushed to the practical conclusion, that the capacity 

 of the furnace should be increased to the point of realising all the 



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

 XXXIV. Session 1871-72, pp. 133-136. 



