ECONOMIC GEOLOGY. 67 



two heaps are distant from each other at the apex about a foot, at the 

 bottom about an inch. This is done in order to rest on the charcoal a 

 kind of funnel-formed channel for the admission of the stream of air 

 produced by the constant action of the bellows. The external aperture 

 of the funnel receiving" the nozzle of the bellows is in breadth 5 or 

 6 inches. Clay is then put upon it, which serves both to fix it and to 

 form the first layer of clay that constitutes the temporary part of the 

 furnace. This part is not to be thicker than 2 inches, and it decreases 

 in thickness the higher it advances. The funnel itself is made of a 

 mixture of clay and husks of rice ; and previous to its application is 

 hardened by fire, and then made firmer in its position by a coat of clay 

 laid over it. 



." The funnel being fixed in this manner, the wall is raised, becoming 

 gradually thinner, so that when it arrives at the middle part, it does not 

 exceed the thickness of an inch. Then a burnt stone of the same 

 thickness, from 10 to 12. inches high and from 8 to 9 broad, is fixed 

 upon it, so that it inclines to the opposite side, the circle becoming" 

 narrower the higher it rises. This stone is connected with the principal 

 wall by means of mud. In this manner the circle is completed ; some 

 holes of 2 inches square being left, one or two on each side. On the 

 stone itself is placed a second stone of the same kind and shape, but 

 smaller, and fixed in the same manner. Its apex is on a level with the 

 top of the opposite or principal part of the furnace. The top of the 

 furnace now serves as the basis for a cone, the use of which is sufficiently 

 obvious. 



"This cone s 12 inches long. Its under-aperture rests on the 

 top of the furnace, where its breadth is 14 inches. At its upper 

 part or apex its diameter is 7 inches. To facilitate the introduction 

 of charcoal and ore into the furnace, the cone is crowned with a large 

 cutcherie pot, the bottom of which is broken out, and thus serves not 

 only to facilitate the introduction of fuel, etc., but is supposed of much 

 consequence as the representation of a swamy. 



" It has been already stated that some charcoal and ore had been 



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