Vickipedia

PACKFO’NG, or PETO’NG, a Chinese alloy or white metal, consisting of arsenic and copper. It is formed by putting two parts of arsenic in a crucible with five parts of copper turnings, or finely divided copper; the arsenic and copper require to be placed in alternate layers, and the whole is covered with a layer of common salt, and pressed down. When melted, the alloy contains nearly the whole of the arsenic, and is yellowish-white in color when in the rough state, but takes a flue white polish resembling silver. It is not very ductile, and cannot be fused without decomposition, as the arsenic is easily dissipated. It was formerly much used in this country, as well as China and India, for making the pans of small scales, dial-plates, and a variety of other articles requiring nicety of make, such as graduated scales for philosophical instruments. It is probably never imported now, the nickel alloys of Europe having quite superseded its use; in China, however, it is still extensively employed.