AMERICAN INDUSTRIES SINCE COLUMBUS. 



163 



either by the " trompe " or by wooden or leather bellows ; and 

 sometimes by what some writers in utter defiance of Euclid and 

 all his disciples have called " square wooden cylinders/' worked 

 by rude water-wheels. 



The ores most frequently reduced in these " blomary fires " 

 were the rich magnetites containing about seventy per cent of 

 iron, although poorer ores could be, and oftentimes were, used. 

 Sometimes the ore was employed in the " raw state " (i. e., just as 



Fig. 10. A Blomary Fire. 



it is taken from the mine), but the best practice was to subject 

 it to a preliminary roasting in heaps. The operation of smelting 

 the ore, or more properly deoxidizing it (for the metallic iron 

 obtained in these "fires" was not the result of a true fusion), 

 was substantially as follows, viz. : The bottom and sides of 

 the "hearth" having been lined with a thick coating of char- 

 coal dust, it was then filled with charcoal, upon which crushed 

 ore was thrown, and kept in place by a dam of charcoal dust (c, 

 Fig. 10). The fire was blown gently at first, and as the heat in- 

 creased a more powerful blast was employed ; ore and coal were 



