51 
working is a tedious and rather laborious process, but a description of the manner 
of doing it will properly come within my account of the Cornwall and Devon¬ 
shire mines. It is a great economy to have the ores submitted to this preliminary 
operation before shipment, as it induces, among other advantages, a very consid¬ 
erable saving in freight; and is, in fact, absolutely essential to the successful 
working of the poorer ores. 
The ore, having been pulverised, is carried by railway and steam power up to 
the Hoppers, from whence it is passed into the furnaces, (below the Hoppers,) 
and there subjected to a high degree of heat, for twelve hours, by which time it is 
well calcined. This drives oft’ much of the arsenic and sulphur with which it is 
combined. It is then carried to another furnace, where it is melted. The slag is 
lighter, floats on top, and is the first drawn off. Fluxes are seldom necessary, 
and never so, except with a very refractory ore, when fluate of lime is used for that 
purpose. The first slag, which is usually remelted, generally acts as a sufficient 
flux of itself. It is often seen crystallized in various forms, exhibiting a beautiful 
pavonine play of colors. The crude copper is now broken up and remelted, with 
a current of air passing through it for the purpose of oxidising the iron with 
which it is mixed, and is then drawn off, into a tank of cold water, to granulate. 
The water is prevented from becoming hot by a cold stream continually running 
through the tank. The object of the granulation is to separate the metal into 
small globules, so that the fire may circulate freely through and amongst it, when 
again subjected to its purifying action. After granulation it is again roasted or 
calcined for thirty hours, and is then removed to another furnace, when it is 
melted, with a draft of air passing through it, as before, to effect a still further 
oxidation of the iron; from this furnace it is drawn oft’ and run into pigs. It is 
then again broken up, remelted, and, in a fluid state, conducted into a refinery, 
among burning charcoal, from whence it is run into ingots, or into plates about 
18 inches square by two or three inches thick. This is sometimes the copper of 
commerce; but it is usually rendered malleable and ductile by the following pro¬ 
cesses, viz: it is clipped, heated, and rolled, and cut into sheets, say two feet 
long; again heated and rolled ; then again heated, doubled , and rolled, and some¬ 
times (depending on its quality) again rolled, without additional heating. 
This is called finishing: it is then immersed in a bath of uric acid for the 
purpose of brightening the metal, and removing the appearance of impurities from 
the surface. It is then put into a furnace ; then immersed in cold water, from 
which it is brought out bright. It is then taken to a machine, where its four 
edges are clipped smooth, leaving it about three feet long and one wide, in thin 
sheets. It is then assorted, weighed, and stamped with the weight per square 
foot, which ranges from 10 to 20 ounces. 
In some of the establishments, the processes are more simple; but I should 
doubt these being so efficient. As, for instance, the metal is granulated from the 
first melting, direct, and after the second melting it is not broken up, but remelt¬ 
ed in mass ; and, in rendering it malleable, it is not always submitted to so many 
heatings and rollings. At Mr. Williams’s works, an engine of horse powe 
