A STUPENDOUS VORTEX 
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 ten or 
twelve feet 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 feet high. As 
we went farther we were in a channel between high rocks 
strewn 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. This was a 
region of highly volcanic origin. No sooner had we passed 
this basin than we came upon another serious rapid, 400 
metres long, which divided itself into two channels, after 
going through a narrow passage not more than thirty 
metres 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 gone only 19 kilometres 600 metres. 
Since we had come to that volcanic region we had found 
rocks with great holes in which stagnant water lay, and 
myriads of insects — regular clouds of them — worried 
us nearly to death. 
On August fourteenth we started early, the minimum 
temperature having been 70° Fahrenheit during the night. 
After leaving the rapid we came to a great basin 1,000 
metres across. A most beautiful sand beach 300 metres 
long was to be seen on the left side, below a vertical cliff 
of great beauty, 200 feet high. Another great sand beach 
211 
