154 GEOLOGY OF TMCHINOPOLYj &C, [ChaP. VIII. 



Inside tlie furnace the ground is generally excavated to the depth 

 of about 1 foot, to form a hearth for the bloom. A semi-cu'cular 

 opening from 1 foot to 14 inches high is either left in the front waU^ or 

 is subsequently cut into it while the clay is still moist. This is filled 

 up with clay before the commencement of each smelting. 



The blast required for the smelting is obtained by using two bellows, 

 each made of a sheep or goat^s skin, and worked 

 by hand in the ordinary way by a man squat- 

 ting in front of the furnace. The nozzles of the bellows are made 

 either of thin sheet iron, or tin plate, or sometimes of bamboos, and these 

 are inserted into a clay tuyere entering at the bottom of the front opening, 

 and carefully luted. The tuyeres reach to the centre of the furnace. 

 The bottom of the furnace is covered with a layer of charcoal dust, to 

 prevent the adhesion of the bloom. By using the bellows alternately, a 

 tolerably continuous blast is produced. 



The furnace is first filled to the top, or veiy nearly so, with charcoal, 



which is ignited by means of a burning ember 



Charge of furnaces. j j.r, -r j. i - a n 



passed tlirougn the tuyere. As soon as flames issue 



from above, a small charge of the powdered iron ore, well moistened to 



make it cake together, is introduced through the apex and covered with 



charcoal ; this is followed by successive charges of ore and fuel, until the 



proper quantity of ore is in the furnace. The blast is now strongly ajoplied, 



and continued from two and a half to four hours, according to the size of 



the furnace. The process is then considered complete, the semi-circular 



aperture in front of the furnace is opened, and the bloom is removed. 



A number of heavy blows with a hammer or mallet are given to knock 



off as much as possible of the adhering oxide, and the bloom is then 



cut half through with a hatchet, and allowed to cool. The object 



of cutting open the bloom in this way is to exhibit the grain to the 



purchaser. 



Charcoal is the only fuel used, but different values are attached to 



Puel. different woods for the purpose of charcoal, and 



frequently two or three different kinds are used at different levels in the 



( 370 ) 



