1. Copper, being easily wrought, is applied to many useful purposes.
It is formed into sheets by heating it in a furnace, and compressing
it between steel rollers. The operation of rolling it constitutes a
distinct business, and is performed in mills erected for the express
purpose.
2. The rolled sheets are purchased according to weight by the
coppersmith, who employs them in sheathing the bottoms of ships, in
covering the roofs of houses, and in constructing steam-boilers and
stills. He also fabricates them into a variety of household utensils,
although the use of this metal in preparing and preserving food, is
attended with some danger, on account of the poisonous quality of the
verdigris which is produced on the surface.
3. An attempt has been made to obviate this difficulty, by lining the
vessels with a thin coating of tin. This answers the purpose fully, so
long as the covering of tin remains entire. But, in cases of exposure
to heat, it is liable to be melted off, unless it is kept covered with
water.
4. This metal can be reduced by forging to any shape; but, during the
process, it will bear no heat greater than a red heat; and, as it does
not admit of welding, like iron, different pieces are united with
bolts, or rivets, of the same metal, as in the case of the larger
kinds of vessels, or by means of solder made of brass and zinc, or
zinc and lead, as in the case of those of smaller dimensions.
5. Brass is applied to a greater variety of purposes in the arts than
copper. This preference has arisen from its superior beauty, from the
greater facility with which it can be formed into any required shape,
and from its being less influenced by exposure to the ordinary
chemical agents.
6. Some of the articles manufactured of brass, are forged to the
required form, and others are made of rolled sheets; but, in most
cases, they pass through the hands of the brass-founder, who liquifies
the metal, and pours it into moulds of sand. For the sake of
lightness, and economy of material, many articles are made hollow; in
such cases, they are cast in halves or pieces, and these are
afterwards soldered together.
7. Pieces which have been cast are generally reduced in size, and
brought more exactly to the proposed form, either in a lathe, with
tools adapted to turning, or in the vice, with files and other
suitable instruments. The operators in brass form a class of mechanics
distinct from those who work in copper.