The
Melting Rooms are
on the first floor, in the west side of the building. Here all
the metal used in coining is alloyed, melted and poured into
narrow moulds. These castings are called ingots; they are
about twelve inches long,
a half-inch thick, and vary from one
to two a half-inches in breadth, according to the coin for
which they are used, one end being wedge-shaped to allow its
being passed through the rollers. The value of gold ingots is
from $600 to $1,400; those of silver, about $60. The fine gold
and silver bars used in the arts and for commercial purposes,
are also cast in this department.
These
are stamped with their weight and value in the deposit room.
The floors that cover the melting rooms are made of iron in
honey-comb pattern, divided into small sections, so that they
can be readily taken up to save the dust; their roughness
acting as a scraper; preventing any metallic particles from
clinging to the soles of the shoes of those who pass through
the department, the sweepings of which, and including the
entire building, averages $23,000 per annum, for the last five
years.
The
copper and nickel melting rooms, wherein all the base metals
used are melted and mixed, is on the same side and adjoining
to the gold and silver department. Up to the year 1856, the
base coin of the United States was exclusively copper. In this
year the coinage of what was called the nickel cents was
commenced. These pieces, although called nickel, were composed
of one-eighth nickel; the balance was copper.
The
composition of the five and three cent pieces is one-fourth
nickel; the balance copper. The bronze pieces were changed in
1859, and are a mixture of copper, zinc and tin, about equal
parts of each of the two last; the former contributing about
95 per cent. There are seven furnaces in this room, each
capable of melting five hundred pounds of metal per day. When
the metal is heated and sufficiently mixed, it is poured into
iron moulds, and when cool, and the rough ends clipped off, is
ready to be conveyed to the rolling room.