GLASS AND IVORY To Cut Glass.—To cut glass with a chisel, cover it with a solution of camphor gum dissolved in spirits of turpentine, and do the cutting while the glass is in the solution.
To Anneal Glass. — To anneal or season glass, as lamp chimneys and the like, so that they will be less likely to break, immerse the glass in a ves sel of cold water and heat it very gradually to the boiling point. Boil for any length of time—the longer the better—and do not remove from the water until it is cold.
Or, if the glass is to be exposed to high temperatures, it may be more perfectly annealed by boiling in the same manner in oil.
To Imitate Stained Glass. — Cut a suitable pattern from leaves of col ored tissue papers, and appl to the glass by any suitable paste or muci lage, as rice or wheat starch, with or without gum arabic. Cover with a coat of copal varnish.
To Soften Ivory.—Dissolve 2 ounces of spirits of niter in 10 ounces of soft water, and soak the ivory in this solu tion for 3 or 4 days, when it will be soft and flexible.
Or immerse the ivory in a solution of pure phosphoric acid until it be comes practically transparent. Wash with clean cold water and dry. It is then flexible, but hardens as it dries. Its flexibility may be restored by soaking in hot water. This process, if continued, will render the ivory transparent.
To Harden Ivory.—Wrap the ivory in tissue paper, cover with dry salt, and lay away a day or two. This will
restore its natural hardness.
To Polish Ivory.—Moisten a piece of felt or velveteen, dip in putty pow der or pumice stone, and polish.
Or fix the ivory on a nail or wheel and polish it by means of pumice stone and water, heat it by friction on a piece of coarse cloth, and while hot rub with whiting mixed with olive oil, followed by dry whiting and clean chamois. This gives a high luster.
Or rub first with fine sandpaper, next with a wet cloth dipped in pum ice stone, then with a cloth wet in soapsuds and dipped in whiting. When changing from a coarse to a finer material, use clean cloths and rinse the article free from grit.
To Etch on the ar ticle with a mixture of white wax and mastic or with a thin coating of bees wax, and trace the required designs through the wax. Take care to pro tect all parts of the article except the design, and immerse it in a strong solution of nitrate of silver. After a sufficient length of time, to be deter mined by experiment, remove and wash in clear, hot water. The design will appear in black upon the ivory.
Or protect the article by a suitable varnish as above, and apply a solu tion of ounce of sulphuric acid, ounce of muriatic acid, and 10 ounces of water. The acids will eat away the exposed portions of the ivory, leaving the design engraved on its surface.