Manufacture of Bar Iron in Southern India, 389 



tain results with minute accuracy, in a process requiring 

 intense heat, that hitherto the phenomena attendent upon 

 the refining of pig iron, and its conversion into bars, may 

 be said rather to be guessed at, than perfectly explained." 

 Upon the same point also Dr. Ure remarks, (Dictionary of 

 Manufacture,) " but philosophers have been, and still are, too 

 much estranged from the study of the useful arts, and con- 

 tent themselves too much with the minutiae of the laboratory 

 and theoretic abstractions." Such being the state of our 

 present knowledge of this subject, it may be doubted if a 

 careful examination of the principles of the long established, 

 cheap, and simple mode of manufacture of the native of 

 India, might not lead to improvements and modifications, 

 which would be found to answer better, than the operose 

 methods of the English manufacture, which require much 

 capital, costly building, and a considerable trade to make 

 them profitable. 



5. In England the fuel now most generally used in smelting 

 the impure iron ores of the coal fields is coke ; and the ore 

 after being first roasted to separate the volatile impurities 3 

 as much as possible, is exposed to its action in blast fur- 

 naces, generally about forty-five feet in height, but varying 

 sometimes from thirty-six feet to even sixty feet. In the 

 middle, these furnaces are about twelve feet in diameter, but 

 at top are contracted to about four feet, and at bottom, 

 where the blast of air is introduced by pipes from powerful 

 blowing machines, the diameter is only about two feet. 

 The pressure upon the air forced into the furnace is about 

 three pounds upon the square inch, and the quantity of air 

 amounts generally to as much as 4,000 cubic feet per 

 minute. The cast iron as it forms, falls down into the bot- 

 tom of the furnace ; which is always hot enough to maintain 

 it in a state of fusion ; where it is protected from the action 

 of the blast by a covering of fused slag which floats upon 

 it. These furnaces are kept in action unremittingly, night 



