IRON. 91 



over them is placed a rectangular box which acts as an air chamber. 

 The tube conveying air to the tuyer is 1| or 2 inches in diameter 

 and passes out from the other side of the air box. 



The blower is worked by a water turbine, which is similar in 

 action to the vertical axled water wheels so commonly used in the 

 Himalayas for the supply of power to corn mills. The motion is 

 conveyed to the piston rod of the blower by means of a wooden 

 crank and long wooden cross-piece. 



The furnace having been filled with a mixture of crude cast 

 iron and charcoal, laid on a charcoal bed in the hearth, is ignited. 

 The blast is then turned on by opening a small wooden slide which 

 allows a strong current of water to fall on to the turbine. A great 

 heat is soon developed, flames of carbon monoxide issue from the 

 top of the crucible, the metal is liquified and collects in the hearth. 

 The tapping-hole is closed by means of a removable clay plug, 

 operated with a long iron rod. As soon as the master smelter 

 considers that sufficient metal has collected m the hearth, the 

 blast is turned off. the blower disconnected, the plug removed 

 from the tapping-hole, the slag carefully cleaned away by means 

 of a long iron bar, and the whole furnace bodily tilted, with the 

 help of a long wooden beam which rests on the ground, and when 

 lifted catches on a projection from the back of the furnace. 



This movement throws the furnace sufficiently out of the vertical 

 to cause the molten iron to flow from the tapping hole, into a large 

 iron ladle, fitted into a wooden handle which rests on the ground 

 and is steadied by another workman. A second wooden beam 

 is fixed in front to serve as a safety device and prevent the furnace 

 being inclined to a dangerous extent. The first bath of molten 

 metal is carefully skimmed, and then stirred with a thick branch 

 of green wood, the gases from which appear to effect the oxidation 

 of some of the impurities in the metal. The furnace is righted and 

 the molten metal emptied in at the top again, whence it percolates 

 through the incandescent charcoal to the hearth once more. The 

 tilting operation is again performed and the molten metal taken 

 a second time into the ladle. A handful of wood ashes is thrown 

 on to its surface and it is poured into the mould. 



The mould used consists of two pieces, both of which are made 

 of thick clay-work, and are bound tightly together with ropes in 

 a bamboo framework. The top part is roughly conical in shape, 

 and its lower portion is hollowed out to correspond with the exact 



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