230 THE SCIENTIFIC PAPERS OF 



of steel melted. There is a further saving in the number of 

 crucibles required, as they may be used in the gas furnace four or 

 five, and sometimes even ten times, while in furnaces heated by 

 coke, two or three casts are as much as are ever obtained. The 

 lining of the furnace lasts at least 15 to 20 weeks without repair 

 (in working day and night), while 4 to 5 weeks is the longest 

 duration of the ordinary coke-fired holes. 



FUSION OF STEEL ON THE OPEN BED. The furnace employed 

 for the fusion of steel on the open bed is similar in shape to a 

 reheating or puddling furnace ; the direction of the flame is from 

 end to end ; and the regenerators are placed transversely below 

 ihe bed, which is supported on iron plates, kept cool by a current 

 of air. The air enters beneath the bed plates in front, and escapes 

 by two ventilating shafts at the back of the furnace near the 

 ends. This cooling of the bed is very necessary to keep the slag 

 or melted metal from finding its way through into the regenerator 

 chambers. The upper part of the furnace is built entirely of 

 Dinas brick. 



There are three doors in the front of the furnace, one in the 

 centre immediately over the tap-hole, and two near the bridges, 

 through which the bed can be repaired when necessary, and ingot 

 ends or other heavy scraps may be charged in. Sloping shoots 

 are provided at the back of the furnace, through which long bars, 

 such as old rails, may be conveniently charged, and beneath these 

 are openings for charging the pig-iron. The upper end of the 

 shoots is on a level with an elevated charging platform behind the 

 furnace. 



The bottom of the furnace is formed of silicious sand, which 

 answers exceedingly well if properly selected and treated. 



Instead of putting moist sand into the cold furnace, as is usually 

 done in preparing the bottoms of furnaces for heating or melting 

 iron or copper, I dry the sand, and introduce it into the hot 

 furnace, in layers of about 1" thickness. The heat of the furnace 

 must be sufficient to fuse the surface of each layer, that is to say, 

 it must rather exceed a welding heat to begin with, and rise to a 

 full steel-melting heat at the end of the operation, in order to 

 impart additional solidity to the uppermost layers. Care must be 

 taken that the surface of the bath assumes the form of a, shallow 

 basin, being deepest- near the tap-hole. Some white sands, such as 



