in many of those places, coming with great force, hit the
bottom and was thrown up again in high waves which swamped our canoe each
time we went through them. In one place we got stuck on a rock in the
middle of the foaming waters, and had a hard job to get the canoe off
again and prevent her sinking when we had done so.

Where the river turned for another 2 kil. 500 m. more to the west,
another elongated island rose on the left side of the stream. The
island--Laurita Island--was only 80 m. broad, but had a total length of
1,800 m.

More rapids and shallow water above a bottom of red volcanic debris were
found. A small tributary 2 m. wide at the mouth entered the Arinos on the
left bank, not far from the spot where a rocky rugged island rose in the
centre of the stream.

I halted at 11.30 in order to take the usual observations for latitude
and longitude and soundings of the river. The stream, which was 320 m.
broad, below some rapids, showed a depth of 6 ft. the entire way across.
Farther down, where it contracted to 200 m. in breadth, it showed a depth
of 8 ft. in the centre with a maximum depth of 10 ft. to the right and
left of it, gradually decreasing to 5 ft., 3 ft., 2 ft., and 1 ft. as it
neared the banks. Lat. 11 deg. 7'.3 S.; long. 57 deg. 46' W.

[Illustration: A Giant Central Wave emerging from a Narrow Channel.]

When we resumed our journey after lunch, we came to another thickly
wooded island, 1,000 m. long, 350 m. wide--J. Carlos Rodriguez
Island--with a cluster of huge rocks on its southern end.

We had a few minutes of comparatively easy navigation, the river being
extraordinarily beautiful in straight stretches of 3,000 m., 2,000 m.,
and 3,000 m., to 340 deg., 350 deg., and 360 deg. (N.) bearings magnetic. In the
first 3,000 m. we came upon another strong rapid over a barrier of rocks
which extended right across the stream. Beyond the rapids the usual
troublesome whirlpools occurred. A polished dome of rock 10 ft. high
emerged in mid-stream. Then another charming island--Nona Island--with a
spit of white sand at its southern end rose gracefully out of the river.
It had a breadth of 100 m. and a length of 600 m.

More _corrideiras_ and eddies had to be gone over that day. We seemed to
be spending our entire time trying to avoid--not always
successfully--collisions with dangerous rocks. We came to another
beautiful island, 200 m. long and 100 m. wide--Emma Island--screened at
its southern end by h