COINING, the art of making money, which has hitherto been performed by the hammer or the mill. The first ope. rations are the mixing and melting of the metal, because there is no species of coin of pure gold or silver but re quires a quantity of alloy. See ALLOY. For gold coin the alloy is a mixture of silver and copper, as silver alone would make the coin too pale, and the copper alone would give it too high a colour. The alloy is used for the purpose of ren dering the coins harder, and less liable to wear, or to be diminished by art. When the gold and silver are completely melted and mixed, they are cast into long, flat bars, nearly of the thickness of the coin to be cast. In coining by the mill, which has been the only method in use for the last 250 years, the bars are taken out of the moulds, and scraped, brushed, flattened in a mill, and brought to the proper thickness of the species to be coined. The plates, thus reduced as nearly as possible to the proper thick ness, are cut into round pieces, called blanks, or planchets, with an instrument fastened to the lower end of an arbor, whose upper end is formed into a screw, which, being turned by an iron handle, turns the arbor, and lets the steel, well sharpened in form of a punch-cutter, fall on the plates; and thus a piece is punch ed out. The pieces are now to be brought to the standard weight by filing or rasping, and what remains of the plate between the circles is melted again. The pieces are next weighed in an accurate balance, and those that prove too light are re-melted ; but those that are too heavy are filed to the standard weight. When the blanks are adjusted, they are carried to the blanching-house, where the blanks are brought to their proper colour. They are next milled, by means of a machine which consists of two plates of steel in form of rulers, on which the edging is engraved, half on the one and half on the other. Being thus
edged, the ;mpression is given them by the mill, which is so contrived, that the metal receives at once an impression on each side, and becomes money as soon as it has been examined and weighed. The process for coining medals is nearly the same with that of money : there is, however, this difference, that money, from the smallness of the relievo, re ceives its impression at once, whereas medals require several strokes. The figures of the coining-mill have been so frequently given, that it seemed to us needless to insert them here, especially as a new method of coining has been in troduced by Messrs. Bolton and Watt, which is shortly to be the only mode used in this country. For this purpose build ings are erecting on Tower-Hill. This machinery, invented by these able me chan;cians, has been long used in the manufacture of copper money ; it works the screw-presses for cutting out the circular pieces of copper, and coins both the edges and faces of the money at the same time, with such superior ex cellence and cheapness of workmanship as will prevent clandestine imitation. By this machinery, four boys are capable of striking 30,000 pieces of money in an hour ; and the machine acts at the same time as a register, and keeps an un erring account of the number of pieces struck.
Commit, in the tin-works, is the weighing and stamping the blocks of tin with a lion rampant, performed by the king's officer ; the duty for every hundred weight being four shillings.