It can, however, be entirely dissolved in boiling alcohol and essential oils. It is one of the most tender of copals. It is also found in Batavia, and this kind is favoured by many on account of the whiteness of its colour.
Gum Benzoin.—This is a compound of many kinds of rosins, some acids, and a certain amount of essential oils. It is easily dissolved in alcohol. The best qualities are obtained from Siam.
Shellac.—This is a rosin which differs in every respect from any other kind. It is somewhat similar to the cochineal, it being the produce of an insect that lives on certain plants. It is soluble in alcohol only, to which it gives its colour. From it, is made the French polish which is mostly used in the furniture trade.
Mastic.—There are two sorts of mastic, that in tears being the purest and best. It comes from Africa, and is partly soluble in alcohol and completely so in ether and essence of turpentine. Mastic is used in all varnishes to render them pliable and to make them dry slowly.
