2208. Cheap Concrete Flooring

2208.    Cheap Concrete Flooring. Mix 3 bushels coal ashes from a blacksmith's shop with 2 bushels gas lime, and then add sufficient gas tar to make a stiff mortar. If the ammoniacal liquor has been separated from the tar, its place must be supplied by adding water till the tar is thin enough for use. For stables and cattle sheds, the mortar can be laid down with a spade, and fine sharp sand or gravel sifted over it; then roll well, and you will have a good concrete floor. It will take a few days to get thoroughly hard, even in dry weather; but it will be a good piece of work, if carefully done. Autumn is the best time for laying this kind of pavement.

2209. Keene's Marble Cement

2209.    Keene's Marble Cement. This is made of baked gypsum or plaster of Paris, steeped in a saturated solution of alum, and then recalcined and reduced to powder. For use, it is mixed with water, as ordinary plaster of Paris. This cement has been most extensively applied as a stucco ; but the finer qualities (when colored by the simple process of infusing mineral colors in the water with which the cement powder is finally mixed for working), being susceptible of a high degree of polish, produce beautiful imitations of mosaic, and other inlaid marbles, scagliola, etc.. The cement is not adapted to hydraulic purposes, nor for exposure to the weather, but has been used as a stucco for internal decorations, and from its extreme hardness is very durable. A pleasing tint is given to this cement by adding a little solution of green copperas to the alum liquor.

2210. Parker's Cement

2210.    Parker's Cement. This valuable 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 burned 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. It is tempered with water to a proper consistence, 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, etc., nothing but cement and water should be employed. This cement, under the name of compo, or Roman cement, is much employed for facing houses, water-cisterns, setting the foundations of large edifices, etc.. It is perhaps the best of all cements for stucco.