PAVEMENT, flat stones or "flags" used for the flooring of halls, kitchens, and other apartments, and frequently for footpaths; also the stone covering of the roadway of streets, The stones used for flags vary in different districts, according to the geological 'formation of the neighborhood. The pavements now most commonly us"d in England and Scotland are the Arbroath and Caithness stones—the former a softer and more agreeable stone than the latter, which is exceedingly hard and slippery when wet. Pavement should be carefully laid on a solid dry foundation, and set in a good bed of concrete or lime, and the joints pointed with cement. It may also he laid on small dwarf walls, built of brick, so as to support all the edges—this is a good method for keeping the floor dry.
The PAVING OF STREETS is of early date, and is, in fact, necessary to any consider able degree of civilization and traffic. The Romans paved their streets in the same elaborate and solid manner in which they paved their highways. Sec ROADS. Portions of the ancient pavement of the streets of Rome are in use to the.present day, and the pavement of 'Pompeii remains entire. It is laid with large blocks of stone of polygonal shape (like-Cyclopean masonry), very carefully fitted together, and of considerable depth, and below there is a carefully prepared basis, often composed of several distinct strata. Some of the Italian towns—Florence, for instance—have still pavement of this descrip tion, and no foot pavement.
The mediaeval cities were almost all unpaved till about the 12th e., when the main streets of the chief towns began to he protected with stone. The plan now adopted is
nearly the sameAn all the cities of Europe. The first thing to be done is to secure or make a solid foundation. This is done, where the natural substratum is not of a solid kind, by laying the street with a solid bed of concrete, a slope from the middle to the sides to throw off the water. On the concrete is placed the real pavement, which is composed of blocks of granite, trap, or other tough rock. These should he rectangu lar, and the deeper the better. They are generally about 10 in. to 12 in, in depth, and 6 in. or 7 in. broad, and from 1 to 2 ft. in They should be all bedded and jointed in strong mortar. This is not often done, as it is thought sufficient to bed the stones in sand, and grout them with hot lime on the top. It is clear, however, that the more equal the stones are in depth., and the more solidly they are bedded, the longer they will last. Other materials besides stone have been tried for the paving of streets—such as blocks of wood with the end up, and blocks of cast-iron. The woodeti pavement is delightfully easy, and not noisy, but in wet weather it is exceedingly slippery. Cast-iron is too hard, causes too much jolting and noise.
The great obstacle in the way of really good pavement in modern streets is the necessity of frequently breaking it up for the laying and repairing of pipes for gas, water, etc. The true remedy—and, in the end, the cheapest—would be to have, in the chief streets at least, sub-ways or tunnels for drains and pipes, accessible without break ing up the pavement.