PLATE, SHEFFIELD. A kind of table ware made by coating a. baser metal with silver. Previous to the introduction of electroplating, the method generally pursued was that which has acquired the name of Sheffield plating, from the large extent to which it was carried on in that town. It consisted in soldering on to one or both sides of an ingot of the baser metal a thin plate of silver. The ingot is always of an oblong shape, and is most carefully prepared on the sur faces which are to receive the silver, so that nothing shall prevent the complete union of the two. The soldering is a process requiring much care and nicety; the plates of silver are thinly coated with a concentrated solution of borax. and are then applied to the prepared surfaces of the ingot, to which they are firmly bound with iron wire, and then placed in the plating-furnace, and subjected to a strong heat. This furnace is
so arranged that the interior can be constantly watched, and when the proper temperature is at tained the workman knows the exact instant to withdraw it. The act of soldering is almost in stantaneous. and fusion would immediately fol low if the ingot was not quickly withdrawn. When cooled. the wire is taken off, and the ingot is taken to the rolling-mill, where it is passed backward and forward, of course with the silver above and below, until it is rolled out into a sheet of the exact thickness required. How ever thin it may be made, it is found that the relative thickness between the ingot and its lay ers of silver is always the same. Practically all plating of metals is now performed by the process of electroplating. See ELEcTIM-CTIEMISTRY. IN DUSTRIAL: TABLEWARE, SILVER-PLATED.