On
the left is the Deposit or Weighing-room, where all the gold
and silver for coining is received and first weighed. The
largest weight used in this room is five hundred ounces, the
smallest, is the thousandth part of an ounce. The scales are
wonderfully delicate, and are examined and adjusted every
morning. On the right in this room is one of the fifteen
vaults in the building. Of solid masonry, several of them are
iron-lined, with double
doors of the same metal and most
complicated and burglar-proof locks.
It
is estimated that about fifteen hundred million dollars worth
of gold has been received and weighed in this room; probably
nine-tenths of this amount was from California, since its
discovery there in the year 1848. Previous to that time the
supplies of gold came principally from Virginia, North
Carolina, and Georgia. During the past ten years considerable
quantities have been received from Nova Scotia, but most of
the gold that reaches the Mint, at the present time, comes
from Montana, Colorado. Idaho, Nevada, Arizona, Dakota,
Virginia, North Carolina, South Carolina, and New Mexico.
Formerly
the silver used by the Mint came principally from Mexico and
South America, but since the discovery of the immense veins of
that metal in the territories of the United States the supply
is furnished from the great West.
The
copper used comes principally from the mines of Lake Superior,
the finest from Minnesota. The nickel is chiefly from
Lancaster County, Pa.
The
Deposit Melting Room
After
the metal has been carefully weighed in the presence of the
depositor and the proper officials, it is locked in iron boxes
and taken to the melting room, where it is opened by two
men,
each provided with a key to one of the separate locks. There
are four furnaces in this room, and the first process of
melting takes place here. 'The gold and silver, being mixed
with borax and other fluxing material, is placed in pots,
melted and placed in iron moulds, and when cooled is again
taken to the deposit room in bars, where it is reweighed, and
a small piece cut from each lot by the Assayer. From this the
fineness of the whole is ascertained, the value calculated,
and the depositor paid. All of the metal is kept in the vault
in the weigh-room until the end of the month and is then
transferred to the Melter and Refiner.
Office
of the Melter and Refiner
Adjoining
the Deposit Melting Room are the Melter and Refiner and
assistants. This is the general business office of the head of
this department, and is also used for weighing the necessary
quantities of the metals used in alloying coin.