Page:TASJ-1-1-2.djvu/228

 river, so entirely destroying its usefulness as a means of transport.

In Bridge building the Japanese have a way of their own which has at least the merit of being quickly, easily, and cheaply accomplished. The piers generally consist of wooden piles driven a few feet into the bed of the streams. In some cases stone is used, but then it is cut to the same shape and of the same size as a wooden pile under the same circumstances would be. The platforms of the bridges are always of wood, and are generally constructed of longitudinal beams formed of a tree grown with such a bend as it may be desired to give the roadway. This bend is always considerable in Japanese bridges. The beams are laid 4 or 5 feet apart, and on top of them are laid cross planks which form the roadway. The span of each opening never exceeds 40 feet and generally is not more than 30 feet. One of the longest bridges in Yedo is at Yae tai and has 24 spans of 30 feet each.

The Japanese seem always to have been alive to the necessities for a plentiful and pure supply of fresh water. Yedo has had its water-works for many years, and the native town of Yokohama will also very soon be supplied with water in the same manner. The source of supply for both places is the River Tame-gawa and the fountain-head is about 13 miles distant from each place. There is a small dam across the river for the purpose of collecting the water into the pipes, but there is no settling pond, filter, reservoir or other such appliance for purifying or storing the water as was used by the ancient Romans and is generally attached to water-works of the present day. The pipes are constructed of wood about 1 or 2 inches thick, and are made in the shape of a square trough, the joints being rendered tight by the insertion between them of a certain bark. The main pipes are from 1 foot to 2 feet square, and the smaller ones used for the distribution of the water are generally about 4 inches square. In the Yedo water-works the pipes are carried across vallies and streams on piles, but at Yokohama syphon pipes have