_United States standards._--The system of coinage in the United States since 1873 embraces standard coins of gold, silver, nickel and copper, but gold alone actually furnishes the standards of value, all other coins being at present subsidiary. Gold is coined for individuals free; that is, a certain weight of metal presented at the mint is assayed, to determine the exact weight of pure gold, and an equal weight of pure gold is returned to the owner in coin. Sometimes a slight charge for the expense of coinage is made and called seigniorage. At present no such charge is made, for the reason that when a nation bears the cost of coinage, foreign coins are kept from circulation, and its own coins are current everywhere.
The standard unit of value for the United States is 25.8 grains of gold nine-tenths fine, and this is called a dollar, although no coin of this weight is at present struck. In actual practice, the standard is shown in the ten-dollar piece, or eagle, weighing 258 grains. The half eagle (five dollars) and the quarter eagle (two dollars and fifty cents) indicate upon their face their relation to the principal coin. The double eagle, or twenty-dollar piece, is coined for greater convenience. These coins connect all the currency of the country directly with the market value of commodities in the world, through gaining their value directly from the market value of gold, where gold is bought and sold. Thus gold furnishes the standard of value with which all other values are compared.
Silver coins of the United States are made from silver purchased by the government. The dollar, adopted from the Spanish rix-dollar, itself derived from the German thaler, is by law a coin of 412-½ grains of silver nine-tenths fine. This silver dollar has a story of its own, which will be given later, and does not form a part of the system of 1873. The half dollar, the quarter dollar, and the dime, for fractional currency, are proportional parts of 385.8 grains of silver nine-tenths fine. These are about five per cent less in weight than the proportional parts of the silver dollar. The original purpose of this reduced weight was to prevent the consumption of these coins in ordinary uses by making them worth on the face a little more than their bullion value. These fractional coins are legal tender in the courts to the amount of five dollars. In nickel and copper coins no effort has been made for many years to maintain a standard of value, the amount of metal in any of them being far less in value than their face. They are legal tender only to the amount of twenty-five cents.