THE AGE OF STEEL 



bricks and the shaft. About this large kettle are 

 smaller kettles of somewhat similar shape having pipes 

 leading from their tops to the larger structure. These 

 smaller kettles are the "stoves" used in producing the 

 hot air for the furnace. 



The working capacity of some of these furnaces is 

 in the neighborhood of a thousand tons of iron a day, 

 although the average furnace produces only about half 

 that quantity. The powerful machinery used for 

 charging these monster caldrons hauls the ore and 

 other charging materials to the top and dumps it in 

 car-load lots. 



In the older methods of manufacturing steel, the 

 contents of the blast-furnaces were first drawn off 

 into molds and allowed to cool into what is known as 

 pig-iron. It was then necessary to re-heat this iron 

 and treat it by the various methods for producing 

 the kind of steel desired. By the newer methods, how- 

 ever, time and money are saved by converting the 

 liquid iron from the blast-furnace directly into steel 

 without going through the transitional stage of cooling 

 it into pigs. Pigs of iron are still made in enormous 

 quantities, to be sure, but mostly for shipment to dis- 

 tant places or for stores as stock material. For statis- 

 tical purposes, however, the entire product of the blast- 

 furnace, whether liquid or solid, is known as "pig iron." 



The older method of removing the iron from the 

 blast furnaces was by tapping at the opening near 

 the bottom, the stream of liquid iron being allowed 

 to flow into a connected series of sand molds, each 

 mold being about three feet long by three or four inches 



[287] 



