29 
Copper . 
veyed by a gutter into a large kind of bucket suspended 
by chains in a well through which a stream of water is 
passing, and here, in falling into the water, the metal is 
granulated, which takes place without explosion or dan- 
ger, and it is then drawn out by raising the bucket. 
The copper is still however extremely impure, though, 
apparently in the metallic state, being grey and perfectly 
brittle, and still mixed with arsenic and sulphur, to sepa- 
rate which is the work of several subsequent processes*, 
It is then remelted and granulated twice more, or oftener, 
each time throwing up a slag in the furnace, which is re- 
moved before the plug-hole is tapped ; but as this slag 
contains some copper, it is not cast into moulds as the first, 
but worked over and over again with the fresh charges of 
calcined ore. The number of fusions and granulations is 
entirely determined by the nature of the ore. The gra- 
nulated mass is then melted and cast into pigs, which 
have a blistered appearance on the surface, and are bro- 
ken up and roasted for one or two days in a low red heat, 
and again melted and roasted as before for several times 
till the metal is considerably purer, and at last is cast in 
oblong iron moulds about 14 inches in length, when it is 
removed to the Refining Furnace . Here it is again melt- 
ed with the addition of a little charcoal, till it is brought 
to a sufficient purity to bear the hammer, and is now good 
saleable copper. 
It is observable that in the former process when the 
crude and brittle metal is cast in sand in the form of large 
pigs or ingots, the best part of the copper rises to the sur- 
face, and when cold may be knocked off with a hammer, 
forming a brittle crust about three-quarters of an inch 
thick, of a grey colour and a steel-like fracture. 
Thus by a series of successive calcinations and fusions 
in the simplest manner possible, the common copper ores 
are freed from arsenic, sulphur and earthy matters, and 
gradually brought to the state of malleable copper. Where 
