(1) The best cement for joining pieces of meerschaum, is Egg Cement, which see. (2) Garlic, crushed to form a sort of dough, is rubbed over the surfaces of the meerschaum to be united; the latter are then bound tightly together with fine wire, and boiled in milk for half an hour. (3) Quicklime is mixed to a thick cream with the white of an egg. These cements will also join fragments of glass or china. Metal to Glass, Stone, Ac. -

For attaching metal plates, such as letters, etc, to flat sheets of glass, the following may be used: - (1) Copal varnish, 15; drying oil, 5; turpentine, 3. Melt in a water-bath and add 10 parts slaked lime. (2) Copal varnish, 15 parts; boiled linseed .oil, 5; Venice turpentine, 5; glue, melted in the smallest possible quantity of water, 5 parts. Melt together and add 10 parts of powdered quicklime. (3) Carpenters' glue, 4 parts; Venice turpentine, 1. (4) Rosin is melted, and into it is stirred calcined plaster till the mass is reduced to a paste, to which is added boiled oil, in sufficient quantity to bring it to the consistence of honey. It is applied warm. (5) Into melted rosin, 180 parts, are stirred burnt umber, 30 parts; calcined plaster, 15 parts; boiled oil, 8 parts. (6) Rosin, 4 to 5 parts; wax, 1 part; colcothar, 1 part; the whole melted together. A little powdered plaster is often added. (7) Sandarac or galipot varnish, 15 parts; boiled linseed oil, 5 parts; turpentine, 2 1/2 parts; essence turpentine, 2 1/2 parts; marine glue, 5 parts; pearl white, 5 parts; dry carbonate of lead, 5 parts; mixed. (8) Copal or lac varnish, 15 parts; drying oil, 5 parts; indiarubber or guttapercha, 4 parts; coal oil, 7 parts; Roman cement, 5 parts; plaster, 5 parts. (9) Copal or rosin varnish, 15 parts; turpentine, 2 1/2 parts; essence of turpentine, 2 1/2 parts; fish isinglass, in powder, 2 parts; iron filings, 3 parts; ochre or rottenstone, 10 parts.

These cements are much used for fixing metallic letters to glass, marble, or wood. The two following are particularly good for uniting brass and glass: - (10) Caustic soda, 1 part; rosin, 3 parts; plaster, 3 parts; water, 5 parts; the whole is boiled. This compound hardens at the end of half an hour; the hardening may be retarded by replacing the plaster by zinc white, white lead, or slaked lime. (11) Fine litharge, 2 parts; white lead, 1 part; copal, 1 part; boiled linseed oil, 3 parts; the whole is triturated together. (12) For joining metallic surfaces where soldering is inconvenient, recourse may be had to a composition formed in the following way: - Pure and finely divided copper, such as that obtained by the reduction of sulphate of copper with zinc clippings, 20 to 36 parts, according to the degree of hardness desired in the cement, dissolved in a sufficient quantity of sulphuric acid to make a thick paste; with this is incorporated, by trituration in a mortar, mercury, 70 parts. The mass is soft, but hardens at the end of some hours. For use, it is heated to 212° F. (100° C), and powdered in an iron mortar heated to 302° F. (150° C.); it then assumes the consistence of wax, and is harder in proportion as it contains more copper.

It adheres strongly on drying. (13) To obtain a cement suitable for joining metals and non-metallic substances, mix liquid glue with a sufficient quantity of wood-ashes to form a thick mass. The ashes should be added in small quantities to the glue while boiling, and constantly stirred. A sort of mastic is thus obtained, which, applied hot to the two surfaces that are to be joined, makes them adhere firmly together. (14) A similar substance may be prepared by dissolving in boiling water 2 1/4 lb. of glue and 2 oz. of gum ammo-niacum, adding, in small quantities, about 2 oz. of sulphuric acid.