AMALGAM. The union of mercury or quicksilver with other metals. Many of these crystallize definitely, and may be separated from the excess of mercury with which they are surrounded. They are mostly brittle and soft. Tin and mercury unite by mere rubbing ; it has a high reflecting surface, and is used as the back of looking-glasses. Amalgam for the electrical machine is made of mercury 4 parts, zinc 2parts, and 1 part tin. These when melted and rubbed up with a little lard are fit for use. AMALGAMATION. The mode by which silver ores may be reduced, mer cury being used in the process. The separation of gold from sand and im purities by mercury is an amalgamation. AMBER. A fossil, vegetable, solid, resin, of various tints of yellow : it is hard and transparent, when polished, a little heavier than water, has a resinous taste, and an odor resembling turpen tine : it burns readily, giving off a white, pungent, aromatic smelling vapor. By friction it becomes highly charged with negative electricity, and from this pro perty being first observed in this mineral, called by the ancients electron, it received the name electricity. According to Gop pert and others, amber is the indurated resin of various fossil trees of the family conifers;. It is found in the same con dition in all latitudes, lying in nodules or masses, disseminated in the sand or fragments of lignite (brown coal) of the plastic clay at the junction of the lower tertiary with the upper secondary bed (chalk): the size varies from that of a nut to masses weighing several pounds.
It is sometimes found containing insects —a yroof of its once being in a soft or senu-fiuid condition. Pictet has num bered 800 fossil species of insects occur ring in it. The feather of a bird and a little of the hair of the bat have been found imbedded, with one or two rnolluscous shells. These species are those which could only have inhabited tropical cli mates. Copal resembles amber, and common copal inclosing insects has been often fraudulently sold for amber. It occurs in Pomerania, and on the other shores of the Baltic, thrown up on the sand after storms. It is also found in the beds of streams. Pits are occasion ally sunk above 100 feet down in the sand, and the amber sought for by a true mining operation. It is found in Sicily associated with bitumen in beds of clay and marl ; also in Poland, Saxony, Siberia, and Greenland. The finer kinds are used for ornament, as ear-rings, bracelets, necklaces, &c. ; and the coarse kind in medicine and the arts. Amber dissolved hi drying linseed-oil makes a good durable varnish. With resin, as phaltum and drying oil, it forms the coaehmaleer's varnish. Amber furnishes an oil used in perfumery and also sue cinic acid used in chemistry. (See V AR