328 THE SCIENTIFIC PAPERS OF 



his reason having been that the powdery material of which an- 

 thracite coke was constituted, required a certain degree of com- 

 pression to bring the particles into contact, and that the absence 

 of this pressure caused the coke to be more or less spongy near 

 the upper surface of the mass. 



In the discussion of the Paper 



"ON A METHOD OF PRODUCING PURE CHARCOAL 

 STEEL DIRECTLY FROM THE ORE," 



By HENRY LAEKIN,* 



Dr. SIEMENS, F.R.S.,* said the old Sheffield method of making 

 cast steel might be called a method by error. They took the ore 

 and smelted it in a blast furnace, turning out a product which 

 consisted of iron mixed with slag, and a great deal of carbon, all 

 the carbon that could be gathered from the ingredients put into 

 the furnace. All that foreign matter had then to be removed, and 

 so it was puddled. The result was iron mixed with slag, but with- 

 out any trace of carbon, or at any rate in no definite combination 

 therewith. This was not what was wanted, which was iron com- 

 bined with carbon, or steel, and so it was again subjected to a very 

 different process, termed cementation, whereby it was kept heated 

 for a fortnight in a furnace, packed with charcoal. This gave a 

 metal which was certainly steel, but it was mixed with slag and 

 full of blisters, so that it was not yet fit to be used. After some 

 years they adopted the method of fusing it in pots, and so pro- 

 duced cast steel such as was used in Sheffield to the present day. 

 Any means of producing this material by a short process must be 

 of great importance to the country, since steel was becoming more 

 essential every day. Several methods of producing steel direct from 

 the ore had been mentioned, but others had been omitted. He him- 



* Excerpt Journal of the Society of Arts, Vol. XXIV. 1875-1876, p. 93. 



