The residue left after distilling off the volatile oil from turpentine.

Properties : Rosin occurs in sharp, angular fragments, amber-colored, usually covered with a yellowish dust and at ordinary temperatures readily pulverized. It is practically insoluble in water, but soluble in alcohol, ether and the fixed or volatile oils.

Action and Uses: Rosin is used as an ingredient of ointments and plasters designed to serve chiefly as stimulating applications to the skin, the simple rosin plaster being used as an adhesive plaster in minor surgery.