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THE POPULAR SCIENCE MONTHLY. 



and others (3 and 4) are removing, by means of levers and roll- 

 ers, the sow last made. The wooden bellows which blow the fur- 

 nace are shown at R, R, R. The furnace illustrated appears to 

 have been constructed with unusual care, its walls having been 



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built of dressed stone laid in regular courses, strengthened at the 

 corners by massive rampant arched buttresses, one of which is 

 marked Z, Z. At B, B, B, are iron bearers that support the 

 masonry of the furnace above the arch ; C, C, are side stones of 

 the hearth ; D is the " tymp ; F, the " dam " ; I, the " tap-hole." 



