As luck would have it, after a chase of several kilometres, over cutting rocks and great banks of sand in which we sank up to our knees—while the naked men with their paddles ran as fast as they could on the opposite bank—the canoe drifted close to the other bank once more, and the men were able to board her. It was a great relief to me when at last the canoe was brought over to our side and we towed her back so as to get the baggage on board and proceed on our journey.
Each of the two men who had rescued the canoe at once received the reward I had offered, and Filippe the negro, who had shown willingness in recovering the boat, also received a handsome present.
The entire day of August 12th had been spent in going those few hundred metres of the rapid. Our camp that evening was but 400 m. from that of the day before.
The minimum temperature of August 12th had been 70° F., whereas during the night of August 13th it was 62° F.
That little adventure had pulled the men together somewhat. I spoke in great praise of the courage that Antonio and Filippe had shown in swimming across the stream.
The river was smooth for a little distance, when we proceeded once more with our navigation; but soon it became narrow—only 40 to 50 m. wide—with strong eddies in its deep channel between rocky sides. Some magnificent sand beaches 15 to 20 ft. high were observed, particularly on the right bank, not far from a tributary 3 m. wide which entered the main river on the left side. Lower down, the river described a sharp turn, and there we met another most dangerous rapid. It was entered by a passage 50 m. wide, after which a circular basin of rock—evidently an ancient crater—100 m. in diameter appeared; then the water flowed out with terrific force by a channel only 30 m. wide. The stream produced prodigious eddies in the circular basin. Waves of great height were dashed to and fro from one side to the other of the narrow channel, between high rocks on either side. The water flowed first in a direction E.S.E. for 500 m., then turned off suddenly to due east for a distance of 400 m. That spot was most difficult for us to go through.
Soon after, the river turned due north and broadened to a width of 120 m. for some 4,000 m. A great basin was crossed, with submerged rocks, forming counter currents of great power and most unpleasant whirlpools. I observed with some concern a stupendous vortex 30 m. in diameter and with a deep central depression. The water revolved with such velocity and force that it formed a series of high-crested white waves running one after another at a terrifying speed around its periphery. The water was raised around the vortex certainly 10 or 12 ft. above the level of the river—owing to the opposition between the rotating water and the current. We gave that vortex as wide a berth as we could; it really frightened one to be near it, although there was no particular danger unless we got right into it.
A charming island was passed soon after, on which, as well as on the left bank, were innumerable rubber trees, but there were none on the right, where chapada was to be seen.
We had in front of us a hill range 300 ft. high. As we went farther we were in a channel between high rocks strewn about along both banks in fragments of great size; then we were once again in a circular basin with high vertical rocks—perhaps another extinct crater. We were here in a region of volcanic formation. No sooner had we passed this basin than we came upon another bad rapid, 400 m. long, which divided itself into two channels, after going through a narrow passage not more than 30 m. wide, where we got tossed about in a most alarming manner, being once or twice nearly dashed to pieces against the rocky sides. We had had so much trouble with the rapids that day that by sunset we had only gone 19 kil. 600 m. Since we had come to that volcanic region we had found rocks with great holes in which stagnant water lay. Myriads of insects—regular clouds of them—worried us nearly to death.
