At length Dick believed he saw the beginning of such a channel, close under the right bank of the river, and waved Vilcamapata to steer the canoe toward it. Half a minute more, and the little craft had darted in between two formidable walls of leaping water and was speeding downward at a speed of fully fifteen miles an hour, with Dick and Phil standing upright and thrusting their long poles first to one side and then the other as Chichester's experienced eye detected the signs which mark the presence of dangerous rocks to right or left, and signalled accordingly. To cry out was utterly useless, the roar and hiss of the tortured waters was far too loud to render even the voice of a Stentor audible, and those behind the pilot could but watch his motions, and act accordingly. Two minutes of strenuous labour brought them to the bend in the river, and this, Dick knew, would be one of the most critical points in the whole run; for it is difficult enough to follow the turns of the channel, even when the course of the river is straight, but when the river as well as the channel bends it is difficult indeed to avoid disaster. Still, Dick remained perfectly cool and self-possessed; the certainty and success with which he had piloted the canoe through that unknown half-mile of chaotic leaping and rushing water had given him more confidence in himself than all the rest of his experience put together, and he felt that unless something quite unexpected and out of the common happened, there was no reason why they should not accomplish the remainder of the run in safety. He held up his hand as a warning to those behind him to be extra vigilant, for they were at what was probably the most dangerous point of the run, and the next instant waved to the Peruvian to swerve the canoe powerfully to the left. The Indian obeyed, to the best of his ability; but he was old, his strength was nothing like what it had been, and the little craft did not swerve quite smartly enough to carry her clear of a rock that lay in her course. Therefore out shot Dick's long pole, and the moment that he felt the jar of it upon the rock he threw his whole weight upon it in the attempt to save the canoe. The shock was tremendous, the canoe was turned violently broadside-on to the current, and at that critical moment Dick's pole snapped clean in two, the recoil sending the youngster headlong into the boiling current, while the next moment the canoe swept up against the submerged rock, was rolled over and over, and her remaining occupants were flung into the swirl.