Platforms

The common platforms for gun batteries require the following materials for each: 5 sleepers or joists, 6 inches square, 14 feet long.—1 hunter, 8 or 10 inches square, 8 feet long, 14 planks, 1 foot wide, 11 feet long, 2¹⁄₂ inches thick.—20 pickets. The usual slope of platforms for guns is one inch to every yard. The platforms for mortar batteries are made with 3 sleepers 8 inches square, and covered with about 11 timbers of the same thickne . They are laid perfectly horizontal, about 15 feet asunder, and 12 feet from the epaulement. This is the distance commonly practised for firing only at 15 degrees elevation; but if the platforms be placed at the undermentioned distances from the epaulement, the mortars may be fired at the angles corresponding. | At | 13 | feet | distance for firing | at | 30 | degrees. | | 21 | feet | at | 20 | | 30 | feet | at | 15 | | 40 | feet | at | 10 | over an epaulement of 8 feet high. See Battery .