Varnish
a thin, resinous fluid, which, when spread over the surface of wood, metal, glass, or other solid substances forms a shining coating, impervious to air and moisture. The great number of varnishes consist of some resinous material, dissolved in linseed oil, alcohol, or some liquid hydrocarbon such as turpentine and benzole. Those made by dissolving a resin in a nonare called oil varnishes; and those preare called oil varnishes; and those prepared by using volatile solvents (alcohol, benzole, etc.) for the resins are called spirit varnishes. In the case of the the varnish dries, SO that when any sur- face is coated with a varnish of this latter the solvent becomes dissipated as face is coated with a varnish of this kind only a film or coating of resin remains, which is apt to crack and peel off; but means are taken either in the preparation of the varnish or in the laying of it on to counteract this tendency. With an oil varnish, on the contrary, the oil remains as part of the coating, giving it toughness, while the resin gives it hardness.