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By the law of April 2, 1792, any person could have gold or silver coined at the mint into lawful money, receiving therefore coins of the same species of bullion, weight for weight of the pure metal contained therein. The standard for gold was eleven parts pure to one alloy; for silver, 1485 parts pure to 179 alloy. The ratio of gold to silver was fifteen to one, and both coins were legal tender. By the law of March 3, 1795, the Treasurer retained twenty-four cents per ounce for silver below the standard, four cents for gold. By the law of April 21, 1800, there was retained for deposits of gold and silver below the standard a sum sufficient for the expense of refinement. By the law of May 8, 1828, a sum was retained from silver bullion requiring the test, for materials and wastage. By the law of June 28, 1834, a deduction of one-half per cent was to be made from all standard gold and silver deposited for coinage, if paid for in coin within five days from deposit. By the law of January 18, 1837, the standard gold and silver coin was made nine-tenths pure, one-tenth alloy and legal tender for any sum. By the law of February 21, 1853, the weight of the half dollar was reduced from 206 ¼ to 192 grains and lesser silver coins in the same proportion; legal tender to five dollars. No private deposits for coinage in these coins were received and charges of one-half per cent were made for refining. By the law of February 12, 1873, the weight of the trade dollar was to be 420 grains, of the half dollar 193 grains; legal tender to five dollars. Silver bullion could be deposited for coinage into trade dollars only; gold for coinage for the benefit of the depositor. The directors of the mint were to buy silver for coins less than one dollar. One-fifth of one per cent was charged for converting standard gold bullion into coin, and silver into trade dollars. Silver coins, except trade dollars, were to be exchanged at par for gold coins in sums not exceeding $100. The charges on gold were removed in 1875. By the law of July 22, 1877, the trade dollar ceased to be a legal tender. By the law of February 28, 1878, silver dollars of 412 ½grains were made legal tender for all debt, and the Secretary of the Treasury was authorized to purchase at market value, and coin not less than $2,000,000 worth of silver bullion per month and not more than $4,000,000 worth per month. By the law of June 9, 1879, silver coins less than one dollar were made legal tender to ten dollars. By the law of July 14, 1890, that of 1878 was repealed and the Secretary of the Treasury was authorized to purchase 4,500,000 ounces of silver bullion per month, issuing in payment United States notes, to be a legal tender; and to make a sufficient monthly coinage for the redemption of these notes. In 1893 the silver-purchase clauses of this act were repealed.