The term bullion, as used at the Mint, includes all gold and silver, whether in the shape of bars, lumps, grains, plate, or foreign coins. All these varieties of bullion are received at the Mint for coinage, but no deposit is received of less value than one hundred dollars.
The weights used at the Mint are Troy weights, and they are always expressed in ounces and decimals of an ounce. Thus, 18 oz. 15 dwt. is written 18·15 oz.
The fineness of bullion is expressed in thousandths. The standard of our coins, as fixed by law, is 900 thousandths; that is, in 1000 ounces of coin, 900 ounces must be pure metal, and 100 alloy. The fineness of deposits is similarly expressed. Thus, 860 thousandths fine signifies that of a given weight (of gold, for instance) 860 thousandth parts are pure gold, and the remainder (140 thousandths) some other metal.
When bullion is left at the Mint for coinage, a receipt is given to the depositor, bearing the date and number of the deposit as entered in the weigh-book, and made payable to him or his order. In this receipt, of course, only the weight of the bullion before melting can be stated; its value depends upon its weight after melting, and its fineness, which is to be subsequently determined by assay.
Each deposit is separately assayed and reported upon by the assayer. Its value is then calculated, and a detailed memorandum prepared, exhibiting the number, date, depositor’s name, kind of bullion, weights before and after melting, fineness, silver parted (if the deposit is gold), value of the gold, value of silver parted, deductions, and net value payable to the depositor. This memorandum is given to the depositor with his coin. Deposits are assayed, calculated, and ready for payment generally within a week after they are made; and they are paid on the surrender of the original Mint receipt.
I have said that the Mint makes no charge for converting bullion into coin. This is strictly true; but, inasmuch as depositors will frequently find by their “memorandums” that certain deductions have been made by the Mint from the proceeds of their bullion, some farther explanations are required. A miller who should grind wheat and corn without taking toll, would be correctly said to grind without charge. And if a farmer should carry his wheat in the sheaf, or his corn in the ear, or corn and wheat mixed together in the same bag, he would hardly object to pay the miller for thrashing, shelling, or separating. If a depositor brings to the Mint bullion “fit for coinage,” that is, of standard fineness and properly alloyed, he will receive in return an equal weight of coins, without charge or deduction of any kind. If, however, his bullion requires refining, alloying, toughening, or separating, to make it “fit for coinage,” this preliminary expense, carefully determined by experience, is deducted from the proceeds of the deposit.
The discovery of the California mines has suddenly increased the deposits at the Mint from five or six millions of dollars annually to thirty or forty millions. The whole amount received at the Mint and branches, from December, 1848, to this date, is about sixty-six millions of dollars. Of this, about twenty-four millions belong to the present year.
The fineness of California gold ranges from about 825 to 950 thousandths. The bulk of them, however, are between 870 and 900, the average being about 884. At this fineness, if entirely free from dirt, an ounce of gold, with the silver contained (deducting Mint charges), is $18 34. There is usually present in California gold a portion of dirt, averaging five or six per cent. of the weight. Five per cent. of dirt would reduce the average value given above to $17 42.
The gold of California contains usually about eleven per cent. of silver. This silver is separated for the benefit of the depositor, when the amount contained in the deposit is sufficiently large to pay the expense of separating, and yield a surplus of at least five dollars. If the surplus is less than this, the depositor receives no benefit from it, the law requiring that it shall accrue to the Mint, and be used for paying ordinary expenses. It is therefore for the interest of depositors to make their deposits sufficiently large to secure the silver contained. At the average fineness of 884, this would require from 75 to 80 ounces.
For more complete information on this subject, your readers may be referred to a small work entitled “New Varieties of Coins and Bullion, &c., by J. R. Eckfeldt and W. E. Du Bois, Assayers of the Mint. 1850,” and to a pamphlet entitled “Guide to the Value of California Gold, by Geo. W. Edelman, U. S. Mint, 1850.”