384 
Tin. 
Into pigs, which are then wrought by the hammer Into 
long flat bars, that are afterwards cut into pieces of about 
ten Indies in length* These are then wrought into plates 
by being heated red-hot, and passed through a flatting 
mill, which consists of two large cylinders of steel, case- 
hardened, and secured in a frame of iron. These are 
placed contiguous to each other, but with a certain inter- 
val of space, and revolve in a contrary direction ; so that 
when one end of the bar is thrust in the space between the 
cylinders, the whole is drawn through and proportionably 
extended and flattened in the passage. The distance be- 
tween the cylinders, which of course determines the thick- 
ness of the plate, is maintained and regulated by screws* 
which tan be altered at pleasure. When the bar is thus 
made into a plate of twice the thickness of the ordinary 
plates, it is heated red-hot, cut in two by a pair of shears, 
and one piece folded exactly over the other, and both re- 
passed repeatedly through the cylinders, till the folded 
plate has extended to the same length and breadth as the 
plate was before cutting. It is then clipped round the 
edges, and the two plates torn asunder (which requires 
some little force) after which they are each finished by 
passing through a finer rolling-press, so as to take away 
every crease or inequality in the plate, and those that are 
too rough to pass through this finer press are thrown 
aside. 
The plates are then steeped in a very weak acid liquor, 
and when taken out are scoured thoroughly with bran s@ 
as to be quite bright and polished to enable the tin to ad- 
here. The tin is melted in deep rectangular crucibles, 
and kept fluid by a moderate charcoal fire beneath. Ta 
prevent its calcination a quantity of grease prepared from 
linseed- oil and suet is constantly kept floating oi) the sur- 
face of the tin and renewed as it evaporates off, which gives 
an excessively nauseous stench. The plate is then tal*en 
