General Burnside's resolve to bombard the place had no power to oust the sharpshooters, even when tons of shells were thrown into its streets, setting fire to many of the buildings. When, after a brief rest, the engineers resumed the construction of the bridges, the same result followed--destruction of their numbers. The town itself was almost impregnable, being completely encircled by hills, save on the river side. These heights were bristling with forts, entrenchments seamed them in every direction, and batteries were planted in such profusion that no opening presented itself for attack. {147} [Illustration: 0156] How long this slaughter would have continued it is hard to tell, {148}but a happy inspiration came to General Hunt, chief of artillery. He suggested that a body of men could make a dash for the river, cross in boats, and besiege the sharpshooters in the houses, driving them out, and taking possession. The daring of the plan almost took away one's breath, but it seemed the only way to silence the enemy's murderous fire, and it was quickly put in execution. The pontoon boats lay at the river bank. A band of tried men was selected for the perilous undertaking, who at a sign, without a sound or word of command, rushed from their concealment, leaped into the boats, shot out from the shore, and were half across the stream before the Confederates realized their intention. Then came a shower of bullets from their rifles, rattling like hailstones about the heads of the brave men, who held boards up before them for protection, dodging the murderous fire as well as they could, while those who were rowing pulled with a will, and the boats were across the stream in swift time. A few were shot, falling into the river, but the largest number went over safely. Reaching the shore, the regiments ran up the hills, and succeeded in forcing the sharpshooters from their lairs, capturing over a hundred of them, while the rest fled to the hills. The way was now clear for the completion of the bridges. A pontoon bridge is a fine piece of ingenuity. Heavy boats, perfectly flat, often twenty feet in length, are anchored at equal distances from each other, lengthwise of the current, and beams are placed upon them to unite them; then strong, thick planks are laid across the beams, thus making a steady, wide roadway, strong enough to endure the weight of horses, heavy pieces of artillery, and the tramp of thousands of men. While the bridge was being made, the enemy did not remain quiet, but dropped shells at various points along the river, which exploded, but happily did little injury. {149} [Illustration: 0158]