Pontoon-bridges.Strips of water a few hundred feet wide often nullify the plans for entire armies. This page of pontoon-bridges gives some idea of the inestimable services of the Engineer Corps. In the upper photograph is one of the pontoon-bridges across the James, at Powhatan Point, near Harrison's Landing, which was used by part of General Grant's army in the march from Cold Harbor to Petersburg. Below to the left is shown a pontoon-bridge over the James with a movable draw, to let vessels pass through. On the right is the pontoonbridge at Broadway Landing on the Appomattox, over which General Smith's corps moved to make the first attack on Petersburg.