The coins at present in circulation in the United States may be classified as gold coins, silver dollars, subsidiary silver and minor coins. The gold coins are the double-eagle, the eagle, the half-eagle, and the quarter-eagle, weighing respectively 516, 258, 129, and 64 1/2 grains of standard gold; that is, of a mixture consisting of nine parts of pure gold to one part of copper. The pure gold in the eagle weighs, therefore, 232 2-10 grains. These coins are legal tender in unlimited quantities for twenty, ten, five and two and one-half dollars respectively, and they are minted free of charge for whoever brings metal to the mint of the requisite degree of fineness. For nearly half a century after the establishment of the first United States mint, in 1793, the eagle contained 270 grains of standard gold .916 2-3 fine, and the alloy consisted of silver and copper mixed. The change to our present system was authorized by the acts of June 28, 1834, and January 18, 1837. For a time also a seigniorage charge of one-fifth of one per cent was imposed, but this regulation was repealed by an act passed January 14, 1875.
Our subsidiary silver coins are the half-dollar, quarter-dollar and dime, weighing respectively 192.9, 96.45, 38.58 grains of standard, or 173.61, 86.805, 34.725 grains of pure silver. The amount of the issue was limited by the acts of July 14, 1875, and April 17, 1876, to about forty-two million dollars, the sum needed to retire the so-called fractional paper currency of that time. This limit has been increased from time to time by special legislation. These coins are legal tender to the amount of ten dollars only, and are reedemable at the treasury or any subtreasury of the United States in sums or multiples of twenty dollars. They are issued in like quantities for lawful money to any person desiring them, and delivered by the government free of charge. At one time half-dimes and three-cent pieces of silver were issued from the mint, but their coinage was ordered discontinued by the mint act of 1873.
The minor coins of the United States are a five-cent piece, weighing 77.16 grains, and made of a mixture of copper and nickel in >the proportion of 75 parts of the former to 25 parts of the latter; a one-cent coin weighing 48 grains, and consisting of a mixture of copper, tin, and zinc in the proportion of 95 parts of the former to 5 parts of the two latter materials. From 1873 to 1890 a three-cent coin of nickel and copper was also in circulation. These coins are legal tender to the amount of twenty-five cents only, are redeemable at any subtreasury in sums of twenty dollars or more, and are delivered free of charge in similar quantities to any person who is willing to pay lawful money for them. Their supply is regulated by the director of the mint, under the supervision of the Secretary of the Treasury, the purpose being to keep in circulation precisely the quantity which is actually needed for the commerce of the country.