Another rapid, fairly violent, was reached some distance beyond, my men this time offering at once, of their own accord, to unload the canoe and take her down carefully with ropes. I pretended not to care, as I wanted to give them a lesson, and said we had better shoot it, as we had done the previous one.
"No, no, no, no!" they all said in a chorus; "there is such a thing as tempting Providence!"
As we got farther down I could perceive that the range extended much farther than I had seen earlier in the day; in fact, from the W.N.W. it spread as far as E.S.E.
Below the last rapid was an island of great beauty—Babin Island—2,000 m. long. The river beyond that island formed two arms, one on each side of a triangular island located in the opening formed in the hill range by the river, where another strong rapid—in fact, a regular small waterfall—was to be found.
It was very difficult to keep count of all the islands which we constantly passed—many elongated, others triangular, others rectangular, others of all kinds of irregular shapes. In my note-books I endeavoured to map out the entire course of the river as well as I could, and I think that, considering the amount of other work I had to do and the difficulties encountered all the time, the map I made to the scale of one centimetre to a kilometre is as accurate as it could possibly be made with the means at my command. In places where I was uncertain I have left blanks in the map, and have not gone in for the usual method of certain geographers of filling up the space with all kinds of shadings in order to make it look pretty.
We had gone that day 46 kil., the current having been very strong all the time, which made up for the loss of time in dealing with the many rapids.
I took altitude observations with the hypsometrical apparatus, water boiling at that spot at 210° 3½, the temperature of the air being 78° F. The minimum temperature during the night of July 30th was 63° F.
We began our journey the next morning by going down a bad rapid and across an awe-inspiring whirlpool. There again we had to lead the empty canoe down with ropes, and even so we had difficulty in getting her through safely.
We were in a region of immense volcanic domes composed of eroded rock, with many small perforations and large holes 2 or 3 ft. in diameter, highly polished inside as if they had been varnished. Those rocks were similar to those I had met in the higher part of the plateau of Matto Grosso. Some of the holes in the rock had been enlarged to a great extent by the water of the river revolving inside them.
After we had passed the great whirlpool we found many curious mounds of sand 20 ft. high among great masses of lava and eruptive rock. Those mounds were formed by musical sand such as we had met before. We called it in this particular place "moaning sand," as instead of whistling as usual it produced a wailing sound like the cry of a hungry puppy.
