Then came a pause, a period of intense waiting, short, but seemingly long, even to the veteran generals, after which the gallant builders, who truly deserved the name of the bravest of the brave, ventured again upon the bridge in the face of those terrible Mississippi rifles. A blast of death again blew upon them. Bullets in hundreds struck upon bodies or rattled on timbers. The workmen could not live in the face of such a fire, and those who had not been slain retreated again to their own side of the stream. A third time the heroic bridge builders returned to their work, and a third time they were driven back by the deadly Mississippi hail. Harry felt pity for them. "I never saw anything braver," he said to Dalton. "Nor did I, Harry, nor anything more useless. The bridge builders never had a chance before the rifles. But now their supports, which should have been there all the time, are coming up." Heavy columns of Union riflemen moved forward to the edge of the river and replied to the Mississippians. But the Southerners, in the shelter of the cellars and pits, held their ground. But few of them were hit and they kept up that deadly hail which swept the uncompleted bridge clear of every workman who attempted to go upon it. The rapid fire of the rifles crashed up and down both sides of the river, two sheets of flame seeming to reach out as if they would meet each other. The wind that had driven away the fog also carried off the smoke, and the river still gleamed like steel between. Then, as the rifle fire died again, there was another silence for a while. "It will take more than rifles," said Harry, "to drive out those intrenched Mississippians." "So it will, Harry," said Dalton, who was watching through glasses, "and here it comes. Their great batteries are about to open." The next instant the whole earth seemed to be shaken by the roar of heavy cannon. The opposing hills and ridges fairly poured forth flame, and shells and solid shot crashed upon the whole devoted town. Nor did this tremendous fire from a hundred and fifty great guns cease for an instant. The roar and crash were appalling. Harry saw houses crumbling in Fredericksburg, with flames leaping up from others.