Shellac forms the foundation of most polishes and spirit varnish. Garnet lac is a very dark variety useful for "black" or varnish for japanningipurposes. Orange shellac has many grades, from common to best. Lemon shellac is for best work. White or bleached shellac is used for decorative work, such as polishing inlaid work aud fancy woods that are to be kept light in colour. It is best to mix the lac when in solution. Gums such as benzoin, sandarach, and mastic are not absolutely necessary in polishes: their object is to gain a bright surface with a minimum of trouble. The addition of such gums and resin converts a simple polish, easy to manipulate, into a varnish difficult to use with a rubber without an undue quantity of oil.