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.

The boys scrambled out without much difficulty, and stood upon the gravelly beach.  They saw at the same moment a man on the bank of the river above, who looked as if he was about to run to their aid; but when he saw that they were safe, he turned around immediately and disappeared.  An instant afterward, Marco, finding that his cap was not upon his head, looked around for it, and, to his dismay, he saw it floating swiftly away down the rapids.  He ran into the water and seized the boat, which was then beginning also to go away.  He called upon the boys to help him pull it up and pour the water out.  He then lanched it again with all speed, seized one of the poles, clambered into it, and pushed off into the swiftest part of the current, and away he went after his cap.

[Illustration:  CAP GONE.]

He resorted to this desperate measure, because he was greatly alarmed at the idea of going home without his cap.  It would have certainly insured his detection, and, as he supposed, a double punishment.  He now was as eager to go down the rapids as he had before been to escape them.  His only care was to keep his boat head down, so that if he should encounter any snag or rock he might not be thrown broadside on.  He kept a good lookout too ahead.  The boat shot through the water like an arrow, and was soon clear of the rapids in the comparatively still water below.