Shellac

A resin; produced as an exudation upon the branches of certain Asiatic trees, such as the banyan (Ficus religiosa). It is due to punctures in the bark of the trees in question, which punctures are made by the female of the insect coccus ficus or c. lacca. Commercial shellac contains about 90 per cent. of resinous material, the rest is made up of wax, gluten, coloring matter and other substances. Shellac is soluble in alcohol, and in aqueous solutions of ammonium chloride, of borax and in strong ammonia solution. Long standing is required in the case of the last named solvent. Dilute hydrochloric and acetic acids di olve it readily; nitric acid slowly; strong sulphuric acid is without action on it. Alkalies di olve it. In electric work it is used as an insulator and dielectric. Its alcoholic solution is used to varnish gla plates of influence machines, for the coils of induction coils and similar purposes. Resistance in ohms per centimeter cube at 28° C. (82.4 F.)--(Ayrton), 9.0E15 Specific Inductive Capacity (Wüllner),   2.95 to 3.73 The same substance in le pure forms occurs in commerce, as stick lac, lump lac, seed lac, button lac.