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THE POPULAR SCIENCE MONTHLY. 



described, the brick-work in the left-hand chambers will have 

 become considerably cooled, and then the " inelter " reverses cer- 

 tain valves (not shown in the figures), causing the currents of gas 

 and air to be reversed that is to say, the gas and air will now 

 come in through the right-hand chambers and pass out through 

 the left. In this way a very intense heat is maintained in the 

 " melting hole," which can be regulated at pleasure by varying 

 the amount and proportion of the gas and air used. The advan- 



Fig. 52. Plan of Siemens Pot Furnace. 



tages of this furnace are sufficiently numerous and important to 

 make its employment compulsory in all well-administered estab- 

 lishments. 



In whatever kind of a furnace the steel is fused, as soon as 

 the metal in the " pots " is thoroughly melted they are re- 

 moved therefrom by a pair of tongs similar to those shown on 

 the "pot" at the right hand of Fig. 53. and the "teemer"then 

 grasps the " pot " with another pair of tongs and " teems " (pours) 

 the fluid steel into an ingot mold of cast iron, care being taken 

 that the stream of metal passes down the center of the mold 

 without coming in contact with its sides. 



The heat of the whole operation of " pulling out " the " pots " 

 and " teeming " the steel (which last is well represented in Fig. 

 53) is so great that the workmen envelop their limbs in thoroughly 

 soaked woolen cloths (technically called "rags "), which require 

 wetting repeatedly during the casting of a " heat " of steel. 



When tlic manufacture of cast steel was first undertaken in 



