Читать книгу A Manual of Mending and Repairing; With Diagrams онлайн

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Wax, including that of bees as well as paraffine, is used in repairs, and forms a part of several cements. On this subject consult Das Wachs, or “Wax and its Technical Applications,” by Ludwig Sedna; Leipzig, 2s. 6d.

Silicate of Soda, or Liquid Glass.—This is generally sold in the form of a very dense liquid. It is prepared by mixing quartz or flint sand with soda, or more rarely with potash. “It is,” says Lehner, “a glass which is distinguished from other glasses by being easily soluble in water. It is believed to be a very modern invention; but I have seen Venetian glasses of the fifteenth century which appeared to be painted with it, or something very similar; and I have found decided indications of a knowledge of it in two writers of the sixteenth century, Wolfgang Hildebrand and Van Helmont. According to Wagner, there are three kinds of liquid glass. By itself liquid glass can only be used for mending glass; but when combined with other substances, such as cement, calcined lime, or clay, or glass, in powder, it forms a body as hard as stone, or a double silicate, which is strongly resistant to chemical influences.” It occupies the first position as an adhesive for glass, nor is it surpassed as a cement in solid form. On this subject vide Wasserglas und Infusorienerde, &c., by Hermann Krätzer; Vienna, 3s.