Stages in the Making of a Big Gun 



At the top, a glimpse of 

 one of the big gun-heat- 

 ing furnaces. The huge 

 steel ingots or blocks 

 are heated before they 

 are worked or forged to 

 a smaller size, just as a 

 blacksmith forges down a 

 tool. Big cranes handle 

 these heavy steel pieces 

 by means of some of the 

 mechanism shown and 

 insert them into a furnace 

 or draw them out with 

 the utmost ease. These 

 heating or soaking fur- 

 naces, as they are called, 

 are fired by gas, oil or 

 .oal. Steel, to be worked 

 or kneaded like bread, 

 must be at a white heat 



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