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Adhesives, Paints, and Varnishes: Amber

Amber. - A resin produced from certain extinct coniferous trees. It occurs as a fossil, usually of a pale yellow color, opaque, or transparent.

It is mined the same as coal in various parts of the world, especially in the vicinity of the Baltic Sea. Small quantities are found in the United States. Amber was much prized by the ancients and was an object of commerce in prehistoric times. It is extensively used for ornaments, especially for the mouthpiece of pipes. Anime. A resin which exudes from a certain tree in Brazil. Used as a medicine and as incense. The name is also applied to a resin known in India as copal.

Copal. - This name is applied to several resins used in varnishes. It is a nearly colorless, translucent substance imported from tropical America, India, and eastern and western Africa. Zanzibar copal is said to be the best.

Lac. A resinous substance caused to exude from certain trees in Asia by the bites of an insect about the size of a louse. The twig punctured by these insects becomes incrusted with lac, sometimes to the thickness of a quarter of an inch. It protects the eggs and supplies food for the young maggots. The mothers are often imprisoned and covered by the sticky fluid, imparting to it a lac dye similar to cochineal. The twigs are broken off before the maggots escape and are dried in the sun. Stick-lac is the crude product or dry twigs. It is not soluble in water except the lac dye or red coloring matter, which washes out. It is partially soluble in alcohol, but not in linseed oil or turpentine.

Seed-lac is the resin removed from the twigs, and washed with water to remove the lac dye or coloring matter. It is coarsely pounded. Lump-lac is seed-lac melted into lumps.

Shell-lac (or shellac) is prepared from seed-lac by melting and straining through cotton. Lac Resin. The essential principle of shellac may be obtained pure by refining shellac, which for this purpose is treated with cold alcohol, filtered, and distilled. It is a brown, translucent, hard, and brittle resin, and is very valuable. Shellac may be dissolved in alcohol, dilute hydrochloric and acetic acids, sal ammoniac, and alkalies. One part of borax dissolved in boiling water will dissolve five times its weight of shellac, making a solution which is as useful for many purposes as spirit varnish. Shellac is much favored as a varnish, being harder than rosin and easily soluble in alcohol. It is also the principal ingredient of the best sealing wax. It is used as a size and has valuable waterproofing qualities.