AMALGAM, the name given to an alloy of mercury and another metal. The amalgams are a very numerous class of compounds, and many of them are used largely in the arts. Many amalgams are produced by direct contact of the metals, with evolution of heat. Others are obtained by the action of mercury on a salt of the metal, or the action of the metal on a salt of mercury, assisted by the passage of a weak electric current in some cases. Some amalgams are solid, others liquid. They are, generally speaking, weak compounds, many of them being decomposed by pressure, and all are decomposed at a white heat. Tin amalgam is used for “silvering” mirrors, gold and silver amalgam in gilding and silvering, cadmium and copper amalgam in dentistry, and an amalgam of zinc and tin for the rubbers of electrical machines. See Mercury and Chemistry.
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