COPPER. 



71 



floor of coarsely powdered charcoal is formed, sufficiently compact to 

 prevent the products of the smeltings sinking into it. These protect it 

 from the blast, and it is besides too compact to burn easily. There is 

 no orifice in the lower part of the furnace. Two clay tuyeres dip nearly 

 vertically about 3 inches into it from the top, and are respectively 

 connected with skin bellows by horizontal tubes about a yard long. The 

 tubes are formed of clay mixed with chopped straw, and are moulded on 

 a straight stick, whicb is subsequently withdrawn. 



The furnace thus prepared is lighted up with charcoal and the 

 bellows at each side worked alternately. When at its full heat, the pow- 

 dered ore is sprinkled in at short intervals, until a sufficient amount of 

 regulus, or ' cheku ' as it is called by the smelters, has collected at the", 

 bottom of the furnace, covered by the lighter slag. The charcoal is tben 

 raked away, and the surface of the slag cooled with a whisp of wet straw 

 tied to a stick. The solidified cake is removed and the fresh surface 

 cooled ; in this way the slag is taken off in two or three successive cakes, 

 leaving the beavier and more perfectly fluid regulus behind, which is 

 afterwards cooled and extracted. 



The regulus (whicb contains some metallic copper disseminated 

 through it, especially in the form of filiform crystals lining the cavities 

 of the vesicular mass) is pounded and ground, mixed with* an equal 

 amount of cow-dung, and made into balls about the size of oranges. 

 After drying, a quantity of these are spread on a layer of charcoal in a 

 place surrounded by stones, and covered by more charcoal. The whole 

 is then ignited, and the regulus thus roasted with free access of air. The 

 roasted balls are subsequently crumbled down and ground, and the 

 powder sprinkled into the furnace in the same way as the original ore. 

 The slag, when the operation is finished, is cooled and removed in cakes, 

 leaving a fluid mass of metallic copper at the bottom of the furnace. 

 The copper is sold in this state at the rate of Us. 2-8 per three sirs, which 

 is equal to about 10^. a pound. It is still vesicular and brittle, and 

 is re-fused before being wrought into manufactured articles, the refined 



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