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THE POPULAR SCIENCE MONTHLY. 



idly to the left, the ball was drawn in between it and the scroll, 

 the teeth on each preventing its slipping ; and, as it was carried 

 around by the movement of the drum, the constantly narrowing 

 space caused the ball to be subjected to great pressure, which 

 expelled the liquid cinder and at the same time forced the ball 



to assume before it was 

 ejected from the ma- 

 chine the form of a 

 cylindrical bloom. In 

 order that the squeezer 

 should accommodate 

 balls of considerable 

 variation in weight, 

 and at the same time 

 exert a powerful end- 

 pressure or " upsetting " 

 during the operation of 

 shingling, a very heavy 

 ring of cast iron (shown 

 in the plane A B, Fig. 

 27) was made to rest 

 upon the upper end of 

 the mass of metal as it 



Fig. 28. Plan of the Eotart Squeezer. 



passed through the machine ; this ring was kept in position hori- 

 zontally and guided in its movement vertically by the upper part 

 of the spindle of the drum b. The finished "bloom" was dis- 

 charged from the " squeezer " at the right-hand side of the open- 

 ing in the " scroll " through which the " ball " originally entered, 

 and such was the rapidity of the operation that the " bloom " re- 

 tained sufficient heat at its close to permit of its being passed 

 directly through the " rolls " and rolled into " billets " or " muck- 

 bars " without reheating. 



The modern form of the above -described machine differs 

 somewhat from that shown in the illustrations in the arrange- 

 ment of its driving-gear, but the general principles embodied in 

 the original construction are still retained. Large numbers of 

 ' Burden Rotary Squeezers " are in use in the rolling-mills of the 

 world, and it may fairly take rank as one of the most important 

 improvements in the manufacture, of iron that have had their 

 origin in America. 



Coincident with the improvements in apparatus and methods 

 for producing wrought iron, the general advancement of all the 

 arts, and especially those relating to the manufacture of ma- 

 chinery, created a demand for forgings of a size impossible of 

 execution by the ancient trip and helve hammers ; and as a means 

 of supplying this need for uncommonly heavy forgings, the 



