Flint Glass

Gla of high specific gravity, low melting point, and high refractive index; used for the manufacture of lenses; made by melting together silica 10, pota ium carbonate 3, and red lead 10 parts. Ordinary flint gla is made from silica 200, soda ash 60, litharge 60, niter 16, and lime 12 parts. It is used for ordinary table utensils. Crystal gla is a fine quality of flint gla . It is easily cut, and its high refractive power of light renders it brilliant. Achromatic lenses are the combination of a lense of flint gla and one of crown gla . See ACHROMATIC OBJECT-GLASS.