Bridges, MILITARY

Generally built of pontoons, which for the reserve bridge train are stiff wooden bateaux of such buoyancy as not to be submerged to within four inches of the gunwale when troops are cro ing. They are placed 20 ft. apart, anchored up and down stream, and support five roadway stringers, called balks, each 25 ft. long, upon which the che or plank for the roadway are placed and secured. The pontoon for the advance bridge train consists of a strong open frame, built of two side tru es united by cro transoms, covered with strong canvas. Its buoyancy is le than that of the wooden pontoon, but, as the two boats can be carried on one wagon, its mobility is much greater, and it is therefore used to accompany cavalry.