128 
Brass* 
of the pieces is carried at a time to the flatting mill, a 
machine not much unlike the rolling press of a copper 
plate printer. The two cylinders are of steel* case-har- 
dened and secured within a frame of iron, A man stands 
on each side, and while the two cylinders revolve, each in 
a contrary direction, one of them lifts up the piece of red 
hot copper with a pair of tongs, and thrusts it between 
the cylinders, the other man on the opposite side securing 
it with his tongs as it passes through. This he lifts back 
again over the upper roller to the first man, who by the 
assistance of a strong screw, diminishes the distance be- 
tween the two cylinders, in order to widen and compress 
the plate still more ; when it is conveyed a second time 
between them. This screw is turned for the same reason 
every time before the plate passes between the cylinders, 
and thus by the most simple process imaginable, the plate 
is gradually reduced as thin and broad as the workmen 
may desire. 
By means of a similar machine, the copper is wrought 
into bars instead of plates, of any form or thickness, with 
equal facility., For the latter purpose, the smooth surface 
of both the cylinders are alike indented with eight, ten, 
or more distinct grooves, all which differ from each other 
in width and depth. The series commences with the 
largest groove, encircling one end of the cylinder ; the 
next in point of size succeeds, and thus they diminish 
gradually to the other extremity of the series, which ter- 
minates with the smallest groove. The piece of copper 
being heated as before to a fiery redness, the workmen 
force it between the first or largest groove of the adjusted 
Cylinders, where it receives either the round or angulated 
form of the groove from the compression of both the 
cylinders, as readily as wax in a common mould. Should 
it be necessary, the bar is conveyed in like manner pro- 
gressively through the second* third* or fourth groove* or 
