530 



BOOK XI. 



and then they dig out with pointed picks the holes hi the cakes, which contain 

 the same kind of copper. The head of the round hammer is three palms and 

 a digit long ; one end of the head is round and two digits long and thick ; 

 the other end is chisel-shaped, and is two digits and a half long. The sharp 

 pointed hammer is the same length as the round hammer, but one end is 

 pointed, the other end is square, and gradually tapers to a point. 



^ *y ^ -\ A ... jfVfr ; V\f^ r> \ *r^ 



C ^ ^ M A /CWM> K' 



A TANK. B BOARD. C TONGS. D " DRIED " CAKES TAKEN OUT OF THE TANKS. 

 E BLOCK. F ROUNDED HAMMER. G POINTED HAMMER. 



The nature of copper is such that when it is " dried " it becomes ash 

 coloured, and since this copper contains silver, it is smelted again in the 

 blast furnaces. 23 



I have described sufficiently the method by which exhausted liquation 

 cakes are " dried " ; now I will speak of the method by which they are made 

 into copper after they have been " dried." These cakes, in order that 

 they may recover the appearance of copper which they have to some extent 

 lost, are melted in four furnaces, which are placed against the second long 

 wall in the part of the building between the second and third transverse 

 walls. This space is sixty-three feet and two palms long, and since each of 



23 See note 29, p. 540. 



