346 THE SCIENTIFIC PAPERS OF 



A mixture is prepared of pulverulent ores combined with fluxing 

 materials and reducing agents in suitable proportions, and of this 

 4 to 5 tons are charged from a platform into the heated chamber 

 to the depth of some 12 or 15 inches. But, before charging the 

 mixture, some coke dust or anthracite powder is spread ov<jr the 

 bottom and sides of the chamber for the protection of its silica 

 lining. The heat of the furnace is thereupon raised to a full 

 welding heat, care being taken that the flame is as little oxidising 

 as possible. The result is a powerful superficial action upon the 

 mixture or batch, causing simultaneous reduction of the ore and 

 fusion of the earthy constituents. In the course of two hours a 

 thick skin of malleable iron is formed all over the surface of the 

 mixture, which, on being withdrawn by means of hooks, is consoli- 

 dated and cleared of cinder under a hammer, and rolled out in the 

 same heat into rough sheets or bars, to be cut up and finished in 

 the refinery furnace or charcoal hearth. One skin being removed, 

 the furnace is closed again, and in the course of 1 \ hours another 

 skin is formed, which, in its turn, is removed and shingled, and so 

 on, until after three or four removals, the furnace charge is nearly 

 exhausted. A fresh charge is then added, and the same operation 

 repeated. Once every 12 hours the furnace should, however, be 

 cleared entirely, and the furnace lining be repaired all round. 



The shingled metal, so produced, forms an excellent melting 

 material for the open-hearth or Siemens-Martin process ; but if 

 ores, both rich and free from sulphur and phosphorus are used, 

 together with roll and hammer scale, which form an admirable 

 admixture, I simplify the process still further in causing the fusion 

 to take place in the reducing furnace. 



The furnace having been charged with say five tons of batch, 

 the heat is allowed to play on it for four or five hours, when about 

 two tons of hematite pig iron are charged upon the surface, by 

 preference in a heated condition. The pig metal on melting con- 

 stitutes a bath on the surface of the thick metallic skin previously 

 formed, and gradually dissolves it on the surface while it is form- 

 ing afresh below, and in the course of from three to four hours 

 the whole of the materials charged are rendered fluid, consisting 

 of a metallic bath, with a small percentage of carbon, covered with 

 a glassy slag containing about 15 per cent, only of metallic iron. 

 The carbon of the bath is thereupon brought down to the desired 



