94 FRANK HEARNE CROCKARD 



45 revolutions, and deliver 57,000 cubic feet of free air per 

 minute at 25 pounds pressure per square inch. The weight of 

 these engines is about 635 tons each. In this connection it is 

 to be regretted that the internal combustion engine, using 

 furnace gases, has not yet fovmd its way into American plants 

 even experimentally. The barbarous practice of developing 

 power by means of the steam boiler continues as the accepted 

 method. From an economic point of view this subject offers 

 a most attractive field, and it is to be hoped that the next 

 epoch in blast furnace practice will record achievements as 

 successful along these lines as those briefly chronicled in this 

 incomplete resume of modern blast furnace practice. 



