Show PROCESS or OF COINING GOLD A united states mint has been completed in son francisco and is probably ere this time in active operation coining down dail daily vast treasures of of golden ore it was anten intended lathat that it should be prepared to coin thirty Tv millions illions of dollars yearly the following description of the system which is about to be established there will afford a good general idea of the ordinary process of coining gold 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 into bars these bars next pass pase through the hands of the assayer who with a chisel chips a small fragment flook each one each chip is then rolled into a thin ribbon and filed down until it weighs exactly ten grains it is then melted in a little cup made of bone ashes and all the base metals copper tin ac are absorbed by the porous material of the cup cap or carried off by oxidation oxy dation 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 loat 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 essayed the bars are melted with a tain 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 an any y 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 re melted the pieces which have been adjusted are run through a milling machine which compresses them to their proper diameter e r and raises the edge two hundred and fifty are milled in a minute by the machine they are then en again am softened by the process of annealing and a after at er a thorough cleaning we are cheed in m a tube connecting with the stamping instrument I 1 A no iban IL I L th vac unc ni a time ilme by the machinery and stamped between the d dies ie a they are now finished and being thrown into a box I 1 are delivered to the treasurer f for or circulation the machinery of course for all these processes must most be of the nicest kind the weighing scales alone in the deposit rooms of the california mint cost 1000 ex |