476] C EM holding together broken glass, kc. For this purpose, the juice of gar- lic Is recommended as exceedingly proper: for it is very strong; and, if the operation be performed with care, leaves very little or no mark. This is also effected, by a prepa- ration of fresh cheese cut in thin slices, which should be boiled in different waters, and continually stirred : thus it is converted into a very tough and elastic mass, which will not incorporate with li- quids. After being sprinkled with a little boiling water, and worked upon a hot stone, a small quantity of unslacked lime should be added, and the whole beat into die con- sistence of a paste. This compo- sition will prove a strong and dar- Cement for wood, stone, earthen ware and glass : when thoroughly dry, it resists every ef- fect of water. There is a cement for joining and china, used in Germany, and which appears to be preferable to that above mentioned. It is prepared as follows: Take, by lire, two parts of litharge, one < : vnslacked lime, and one of flint ■ each be separately re- I to the finest powder, and kedup into a paste with old ig oil. Hm Tiifir'iMEK asserts, nd is very durable, icquires a greater degree of i immersed in w a- I Another composition, which is successfully employed by the Ger- mans, ■ '. is pre- pared from pitch, mixed with bul- locks'-blood, linseed-oil, and tur- pentine. The v hole of these must be put over a fire, in an iron pan, and as much brick-dust added as will make them of the consistence thin pa.-tc. The tub, or c CEM to which this preparation is to b^ applied, must be perfectly dry be- fore it is laid on ; and the chinks or crevices filled up with tow, ■while the cement is warm. Some melt a due portion of colophony with the other liquids, previously to the adding of the brick-dust ; by which means the composition is said to be much improved. Cement, in building, is used to denote any kind of mortar, which is stronger than that usually employ- ed. The cement commonly used, is either cold or hot . The former is the second above described, for ce- menting china, &c. which is some- times, though seldom, resorted to in the erection of walls. The hot cement, in general use, is made of resin, bees-wax, brick- dust, and chalk, boiled together. The bricks to be conjoined are heated, and rubbed together, with cement between them. If the as- sertion of foreign writers be well- founded, there is a much superior composition for cementing stones prepared on the Continent. It eon- sists of eight parts of pitch, tour of colophony, two of minium, or very fine litharge ; two of white lead ; and one of brick-dust, melted to- gether. Sometimes, however, the following materials are substituted for those last mentioned : Take. pare quartz, reduce it to a fine powder, by means of the same free- stone, to v hich it is to be applied; add one thirdpart ofunsb.ckcdlime, and work the whole into a paste with the whites of eggs, just be- fore it is wanted. So effectual is this preparation, that in a few mi- nutes it will acquire the compact ness and solidity of iron. A cement of tolerable firmness may be obtained, by a mixture of gypsum and quick-lime, with the ■ addition
