In such a furnace not more than 400—500 qumnme=z 3,3'iO to 4,100 lbs. Eng- 

 lish can be smelted in a day, and the larger establishments have therefore often 

 a number of 30 or more furnaces in operation. The fuel consumed is about 30 

 to 70 % °f the weight of <he ore. 



As already observed, this kind of furnace serves with certain modifications for 

 nearly all sorts of smelting; only for the production of pig-iron a kind of rachette- 

 furnace on a small scale, with several tuyeres placed opposite to each other, is 

 used here and there. 



To refine copper, crucibles of clay are employed ; for cupelling, tests. 



THE CHAEGE. 



In preparing the charge, the object is to procure a tough — mostly highly 

 silicated-slag, which can be easily removed in skins from the bath ; it is thereby 

 net to be avoided that the same, in consequence of its consistency, contains many 

 mechanically enclosed particles of metal and regulus. The charge is either 

 added at the same process or pounded and washed, or smelted separately, as 

 long as a profitable result is still obtainable. 



The fuel is everywhere charcoal, mostly hard one. 



There is no control whatsoever with the smelting through current assays, 

 and through smelting-books only a very insufficient one. Under these circum- 

 stances great loss of metal is of course unavoidable ; scoriae for instance, which 

 by repeated smelting yield no regulus, are thrown away, although they often 

 contain a still considerable quantity of useful metals, — for instance lead, copper 

 &c. — as silicate. 



As the same construction of furnace serves for smelting the most heteroge- 

 neous metals, so the smelting process itself offers only insignificant variations. 

 It would appear, that the same process and the construction of furnace, as 

 were also customary elsewhere in Asia, for instance in India, were here original- 

 ly used for copper-ore, and afterwards applied also to other metals. 



DEFECTS IN THE OLD SMELTING PEOCESS. 



That the adoption of the same construction of furnace and of the same process 

 in the treatment of all metals, must have its disadvantages, and these of a 

 grave nature, is selfevident. The construction of the smelting furnaces is 

 generally open to the following objections : 



1. It causes an enormous consumption of fuel, firtt, because the heat from the 

 charcoals, which are burning so to speak in an open heap, is not at all kept 

 together ; secondly, because the furnace requires every day to be warmed anew, 

 and thirdly because, while the smelting is going on, the already red-hot charge 



