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.