The jewellers of Turkey, who are mostly Armenians, have a singular method of ornamenting watch cases, etc., with diamonds and other precious stones by simply gluing or cementing them on. The stone is set in gold or silver, and the lower part of the metal made .flat or to correspond with that part to which it is to be fixed. It is then warmed gently and the glue applied, which is so very strong that the parts thus cemented never separate. This glue, which will firmly unite bits of glass and even polished steel, and may, of course, be applied to a vast variety of useful purposes, is thus made: Dissolve five or six bits of gum mastic, each the size of a large pea, in as much alcohol as will suffice to render it liquid; in another vessel dissolve as much isinglass, previously a little softened in water, (though none of the water must be used,) in good brandy or rum, as will make a two-ounce phial of very strong glue, adding two small bits of gum galbanum, or ammoniacum, which must be rubbed or ground until they are dissolved. Then mix the whole with a sufficient heat, keep the glue In a phial closely stopped, and when it is to be used set the phial in 6oiling water. To avoid the cracking of the phial by exposure to such sudden heat, use a thin green glass phial, and hold it in the steam for a few seconds before irunersing it in the hot water.
Finely powdered white sugar, 1 oz.; finely powdered starch, 3 oz.; finely powdered gum arabic, 4 oz. Hub well together in a dry mortar; then little by 1'ttla add cold water until it is of the thickness of melted glue; put in a wide mouthed bottle and cork closely. The powder, thoroughly ground and mixed, may be kept for any length of time in a wide mouthed bottle, and when wanted a little may be mixed with water with a stiff brush. It answers ordinarily for all the purposes for which mucilage is used, and as a cement for labels it is specially good, as it does not become brittle and crack off.
Take the curd of skim-milk (carefully freed from cream or oil), wash it thoroughly and dissolve it to saturation in a cold concentrated solution of borax. This mucilage keeps well, and as regards adhesive power far surpasses the mucilage of gum arabic.
Casein dissolved in soluble silicate of soda or potassa, makes a very strong cement for glass or porcelain.
Take skim milk cheese, cut it in slices and boil it in water. Wash it in cold water and knead it in warm water several times. Place it warm on a levigating stone and knead it with quicklime. It will join marble, stone or earthenware so that the joining is scarcely to be discovered.
To three parts of fresh beaten blood are added four parts of slaked lime and a little alum; a thin, pasty mass is produced, which can be used immediately. Objects which are to be made specially water-proof are painted by the Chinese twice, or at the most three times. Dr. Scherzer saw in Pekin a wooden box which had travelled the tedious road via Siberia to St. Petersburg and back, which was found to be perfectly sound and water-proof. Even baskets made of straw became, by the use of this cement, perfectly serviceable in the transportation of oil. Pasteboard treated therewith receives the appearance and strength of wood. Most of the wooden public buildings of China are painted with schio-liao, which gives them an unpleasant reddish appearance, but adds to their durability. This cement was tried in the Austrian department of Agriculture, and by the " Vienna Association of Industry," and. in both cases the statements of Dr. Scherzer were found to be strictly accurate.