Clean the plaster-of-Paris casts and other objects free from dust and stains, and apply this mixture with a paint brush as long as the plaster of Paris will absorb it. Let dry and dust with a brush or chamois leather. Repeat, if necessary, until the casts take on a satisfactory polish.
To Make Artificial Marble. — Mix plaster of Paris with a solution of alum, put it in an oven, and bake un til the water is completely evaporated. Afterwards grind to powder. Mix with water and stir in any desired coloring matter in powdered form to make clouds and veins. When dry, this mixture sets very hard and takes a high polish.
To Imitate Alabaster.—To imitate alabaster with objects made of plaster of Paris, warm the articles and sus pend them by means of horsehair or fine wire in melted white wax of the best quality. Continue until the plas ter of Paris has absorbed all it can. Hang up the articles to dry, and pol ish with a clean brush. Any pure white wax will answer this purpose. To harden these objects, suspend them in a clear solution of alum un til crystals form upon the surface. Remove, and polish with kt damp cloth.
To Clean Alabaster. — Wash with castile soap and water.
Or, to remove stains, cover with white fuller's earth or pipe clay. Let stand for a few hours and wash off.
Or, if much stained, wash with very dilute sulphuric acid, using about 1 ounce of sulphuric acid to 20 ounces of water.
Or rub with a cloth moistened with lemon juice and dipped in pumice stone. Rinse with clear water and polish with a dry chamois.
To Make Prepared Chalk.—Add a solution of carbonate of soda to ti solution of muriate of lime as long as the chalk is precipitated. Strain through filter paper and then pour on clear water until the sediment is perfectly clean. Dry in direct sun shine.
Safety Matches.—To make safety matches, mix 6 ounces of chloride of potash, 2 ounces of bichromate of pot ash, 2 ounces of ferric oxide with S ounces of strong liquid glue. Mix
thoroughly with gentle heat, taking care that it does not take fire, and dip the match heads in this. These matches will not kindle on sandpaper or by ordinary friction, but must be rubbed on a surface especially pre pared for them as follows: Mix 10 ounces of sulphide of anti mony, 2 ounces of bichromate of pot ash, 2 ounces of oxide of iron, lead, or manganese, 1 ounce of glass pow der, 2 ounces of strong glue or gum. This preparation is spread like paint while warm on suitable paper, which is fastened on the boxes containing the matches.
Or dissolve 4 ounces of gum arable in just enough water to make thick mucilage or paste, and stir in 4 ounces of powdered peroxide of man ganese, 2i ounces of phosphorus, and place on the back of a closed stove, but do not heat above 130° F. or ex pose to an open flame. Stir until the phosphorus is melted, then add Si ounces of niter and stir the whole to a uniform paste. First dip the matches in melted brimstone, let dry, and afterwards dip the heads in this substance. This mixture may be per fumed by the addition of i ounce of gum benzoin. The lids of the boxes may be coated with the same mix ture by means of a brush, or pieces of sandpaper may be coated in the same manner, and attached to match safes or boxes for convenience in lighting.
Ordinary Matches. — Dip the matches first in hot melted sulphur, let dry and steep in turpentine. Af terwards dip the heads in a mixture of 5 ounces of chloride of potash, 5 ounces of flowers of sulphur, 1 ounce of vermilion mixed to a paste with oil of turpentine.
Or dip the matches in hot melted sulphur, steep in turpentine, and dip the heads in a mixture of 4 ounces of melted glue, 1 ounce of phosphorus with the addition of whiting stirred in to make it of the right consistency, and vermilion or lampblack to color.