relatively unimportant. Before leaving the subject of gold, it may be interesting to the reader to trace the process of its coinage, which may thus be briefly stated. The metal, after being received in the deposit-room, is carefully weighed, and a receipt given. Each deposit is then melted separately in the melting-room, and molded into bars. These bars next pass through the hands of the assayer, who with a chisel chips a small fragment from each one. Each chip is then rolled into a thin ribbon, and filed down until it weighs exactly ten grains. It is then melted into a little cup made of calcined bone ashes, and all the base metals, copper, tin, &c., are absorbed by the porous material of the cup or carried off by oxydation. The gold is then boiled in nitric acid, which dissolves the silver which it contains, and leaves the gold pure. It is then weighed, and the amount which it has lost gives the exact proportion of impurity in the original bar, and a certificate of the amount of coin due the depositor is made out accordingly. After being assayed, the bars are melted with a certain proportion of silver, and being poured into a dilution of nitric acid and water, assume a granulated form. In this state the gold is thoroughly boiled in nitric acid, and rendered perfectly free from silver or any other baser metals which may happen to cling to it. It is next melted with one-ninth its weight of copper, and, thus alloyed, is run into bars, and delivered to the coiner for coinage. The bars are rolled out in a rolling-mill until nearly as thin as the coin which is to be made from them. By a process of annealing they are rendered sufficiently ductile to be drawn through a longitudinal orifice in a piece of steel, thus reducing the whole to a regular width and thickness. A cutting-machine next punches small round pieces from the bar, about the size of the coin. These pieces are weighed separately by the “adjusters,” and if too heavy are filed down; if too light they are melted again. The pieces which have been adjusted are run through a milling-machine, which compresses them to the right diameter and raises the edge. Two hundred and fifty are milled in a minute by the machine. They are then again softened by the process of annealing, and after a thorough cleaning are placed in a tube connecting with the stamping instrument, and are taken thence one at a time by the machinery, and stamped between the dies. They are now finished, and, being thrown into a box, are delivered to the treasurer for circulation. The machinery, of course, for all those processes, must be of the nicest kind. When in full operation, a mint like that of England, or that of the United States at Philadelphia, can coin millions on millions in a year. QUICKSILVER MINES.