2. Beeswax, 1 oz.; resin, 15 oz.; melt and add whiting (previously made red hot, and still warm), 4 oz.
3. Resin, 1 lb.; melt and add plaster of Paris (dry), 4 oz. The above are used to fix glasses, stones, &c., while polishing and cutting them. The last is a very strong cement for rough purposes.
Cement, Oxychlo′′ride of Zinc. (Sorel.) Prep. In solution of chloride of zinc, marking from 50° to 60° of Baumé’s hydrometer (i.e. sp. gr. 1·490 to 1·652), dissolve 3% of borax or sal-ammoniac; then add oxide of zinc which has
been heated to redness, until the mass is of a proper consistence.
Obs. This cement becomes as hard as marble. It may be cast in moulds like plaster of Paris, or used in mosaic work, &c.
Cement, Parabol′ic. Syn. Universal cement. Prep. Curdle skim milk with rennet or vinegar, press out the whey, and dry the curd by a very gentle heat, but as quickly as possible. When it has become quite dry grind it in a coffee or pepper mill, and next triturate it in a mortar until reduced to a very fine powder. Mix this powder with 1⁄10th of its weight of new dry quick-lime, also in very fine powder, and to every ounce of the mixture add 5 or 6 gr. of powdered camphor; triturate the whole well together, and keep it in wide-mouth 1-oz. phials, well corked. Used to join glass, earthenware, &c. It is made into a paste with a little water, as wanted, and applied immediately.
Cement, Parian. Is prepared as Keene’s, substituting a solution of borax (1 part of borax to 9 of water) for a solution of alum.
Cement, Park′er’s. This cement is made of the nodules of indurated and slightly ferruginous marl, called by mineralogists “septaria,” and also of some other species of argillaceous limestone. These are burnt in conical kilns, with pit coal, in a similar way to other limestone, care being taken to avoid the use of too much heat, as if the pieces undergo the slightest degree of fusion, even on the surface, they will be unfit to form the cement. After being properly roasted the calx is reduced to a very fine powder by grinding, and immediately packed in barrels, to keep it from the air and moisture.
Uses, &c. This cement is tempered with water, and applied at once, as it soon hardens, and will not bear being again softened down with water. For foundations and cornices exposed to the weather it is usually mixed with an equal quantity of clean angular sand; for use as a common mortar, with about twice as much sand; for coating walls exposed to cold and wet, the common proportions are 3 of sand to 2 of cement, and for walls exposed to extreme dryness or heat, about 21⁄2 or 3 of sand to 1 of cement; for facing cistern work, water frontages, &c., nothing but cement and water should be employed. Under the name of compo’ or Roman cement it is much employed for facing houses, water cisterns, setting the foundations of large edifices, &c.
Cement, Pew’s. Quick-lime, 1 part; baked clay, 2 parts (both in powder); mix and calcine; then add gypsum (fresh baked and in fine powder), 1 part, to powdered baked clay, 2 parts; mix well, add the former mixture, and incorporate them well together. Used to cover buildings. It is applied like mortar, and is very hard and durable. See Cement, Gibbs,’ &c.