So the boys all took their poles and began to push the boat up the stream; but they found it harder than they had expected. In fact, the boat had drifted down nearer to the rapids than they ought to have allowed it to go. The water was running quite swiftly where they were, and they soon found that all their efforts were not sufficient to stem the current. The boat was carried round and round in every direction, excepting up the stream. In fact the current was rapidly acquiring the entire mastery over them, and hurrying them down to a point where the water poured on in a furious torrent through a long narrow passage between beds of stone and gravel. "Pull, boys, pull!" said Marco; "we shall go down over the rips in spite of every thing." The boys did pull, but they could effect nothing. The water was sweeping them along with great rapidity, notwithstanding all their struggles. Finally, when they found that they could not make head against it, so as to go up the stream, they concluded to pull for the shore. They were not in any great fear, for the river was very narrow and not more than knee deep in the rapids, so that there was no real danger of any calamity greater than getting well wet. They seemed to be also in a fair way to escape this, for they found that they could make some progress in getting their boat toward the shore. But, just as they began to think their object was about to be accomplished, they were arrested by a sudden mishap. It happened that there was a little snag in the river, nearly in the direction in which they were going. It was the end of a small log, which rose almost to the surface of the water. The greater part of the log was firmly imbedded in the sand, but there was a small portion of it which projected so far as barely to be submerged. The boys did not notice this, and, in their eagerness to run the boat ashore, it happened that they were running it across the current, just above this snag. But as the current was sweeping them down the stream at the same time that they were pushing themselves across it, it carried the boat with great force against this snag. The bottom of the boat was confined by it, while the force of the current, still pressing upon the side, overset it in a moment, and threw all the boys out into the water.