It happened that just below the place to which the boat had drifted before they overtook it, the water became somewhat deeper, and of course more smooth and still, so that it afforded a favorable place for navigating such a boat.  In fact, the character of the stream, throughout its whole course for several miles, was to present a constant succession of changes, from deep and almost still water, to shallow and rapid currents, rippling over beds of sand and gravel.  One of these rapids, or rips, as they were called, the boys had just passed; it being in one of them, though one more broad and less rapid than many of the others, that they had pursued and overtaken the boat.  In the smooth and still water below, therefore, they had a very favorable opportunity to try their boat, for the water, though not so shallow as it was above, was still not so deep as to prevent their propelling their boat, by pushing their poles against the bottom.  It required some care to preserve their equilibrium, but then the water was not deep, and they knew, therefore, that there was no danger of being drowned if they should upset.

Things went on very prosperously, until, after a few minutes, the boys suddenly found themselves drifting into deeper water.  Their poles would scarcely touch the bottom.  Marco, who was not much accustomed to this kind of navigation, was at first somewhat alarmed, but the other boys told him to keep quiet, and they would soon drift into shallow water again.  They accordingly drew in their poles, and began to look over the edge of the boat into the water, to see if they could see any eels.  They saw no eels, but the water soon began to grow shallow again, and so the boys, feeling that they were in no danger, remained quietly in their places, looking idly into the water, talking about the various objects which they saw upon the bottom.

After some minutes spent in this manner, one of the boys looked down the stream, and saw that the boat was gradually approaching another of the rapids.

“Come, boys,” said he, “we must go to work, or we shall be down over the rips.”

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.”