The Galaxy 4, 1871
Professor Böttger calls attention to a very strong and durable cement which he prepares by thoroughly mixing finely pulverized chalk with soluble glass. One of its chief recommendations is the ease with which coloring matters can be incorporated with it without in any way impairing its value. Various substances are suggested by Professor Mager for this purpose. Well-sifted sulphide of antimony gives a black mass, which after setting can be polished with agate, and then presents a fine metallic lustre. Fine iron dust gives a grayish-black cement. Zinc dust gives a gray exceedingly hard cement, capable of being polished, when it gives out the lustre of zinc. Carbonate of copper gives a bright green cement; sesquioxide of chromium, a dark green cement; Thénard's blue, a blue ce* ment, litharge a yellow, cinnabar a bright red, carmine a violet red. Sulphide of antimony and iron dust stirred into the soluble glass afford an exceedingly firm black cement. Zinc and iron dust in equal proportions yield a. hard, gray cement. The soluble glass gives with fine white chalk alone a white cement of great beauty and hardness. All the materials are durable and cheap, and when kept on hand the mixture is readily made at any time.
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