Ponton

or PONTOON, a kind of flat bottomed boat, whose carca of wood is lined within and without with tin: they serve to lay bridges over rivers for the artillery and army to march over. The French pontoons, and those of most other powers, are made of copper on the outside: though they cost more at first, yet they last much longer than those of tin; and, when worn out, the copper sells nearly for as much as it cost at first; but when that of tin are rendered usele , they sell for nothing. The British pontoons are 21 feet long, 5 feet broad, and depth within 2 feet 3 inches.