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planchets, established, coinage and cut

MINT, the place where a country's coinage is made and issued under spe cial regulations and with public authority. In former times the coinage was made by contact at a fixed price. The present mint on Tower Hill, in London, was erected between the years 1810 and 1815. The English mint supplies the whole of the coinage of the British Empire, ex cept Australia and the East Indies. In the United States there are mints at Philadelphia, established in 1792; at San Francisco, established in 1853; and at Denver, established in 1862.

In the United States the Bureau of the Mint was established as a division of the Treasury Department in 1873. It has charge of the coinage for the gov ernment and makes assays of precious metals for private owners. The rolling machines are four in number. The roll ers are adjustable, and the space be tween them is governed by the operator. About 200 ingots are run through per hour on each pair of rollers. When the rolling is completed the strip is about six feet long. As it is impossible to roll perfectly true, it is necessary to "draw" these strips, after being softened by an nealing. The drawing benches resemble long tables, with a bench on either side, at one end of which is an iron box se cured to the table. In this are fastened two perpendicular steel cylinders. These

are at the same distance apart that the thickness of the strip is required to be. It is drawn between the cylinders, which reduces the whole to an equal thickness. These strips are now taken to the cut ting machines, each of which will cut 225 planchets per minute. The press now used consists of a vertical steel punch. From a strip worth $1,100 about $800 of planchets will be cut. These are then removed to the adjust ing room, where they are adjusted. After inspection they are weighea on very accu rate scales. If a planchet is too heavy, but near the weight, it is filed off at the edges; if too heavy for filing, it is thrown aside with the light ones to be remelted. The planchets, after being adjusted, are taken to the coining and milling rooms, and are passed through the milling ma chine. The planchets are fed to this machine through an upright tube, and as they descend are caught on the edge of a revolving wheel and carried about a quarter of a revolution, during which the edge is compressed and forced up. By this apparatus 560 half-dimes can be milled in a minute; for large pieces the average is 120. The massive but deli cate coining presses coin from 80 to 100 pieces a minute.