Etching Upon Ivory. Cover the ivory with wax, hard varnished, or an etching ground, execute the required design, border with wax, and pour on sulphuric acid, hydrocloric acid, or a mixture of equal parts of both acids; when etched sufficiently, wash well, remove the wax, varnish, or etching ground with oil of turpentine, and rub well with old linen rag. Some persons rub a black varnish into the etched parts to give a greater effect. The varnish is made of lamp-black and common turpentine varnish, and the surface is rubbed clean off, leaving only the dark parts visible.
Etching (Upon EgG-shells). Cover the shells with appropriate designs in tallow, or varnish, and immerse in strong acetic acid; they will then come out in strong