in the
river would inundate the country. The forest was particularly thick, and
the rubber trees plentiful, along a stretch of 4,300 m. of river in a
perfectly straight line.

The river was getting more and more beautiful at every turn. We emerged
into a bay 300 m. in diameter. Great blocks of conglomerate were strewn
about. A great spur projected to the centre of the bay. The richness in
rubber of that region was amazing. Wonderful giant trees, heavily laden
with dark green foliage, were reflected in deeper tones in the water of
the river--there almost stagnant because held up by some obstacle lower
down. Innumerable festoons of creepers hung down from those trees. The
stream was there 80 m. wide, and beautiful that day in great stretches of
4,300 m., 1,400 m., 1,000 m., 3,000 m., 1,500 m., and 1,200 m.--in a
perfectly straight line. The forest was occasionally interrupted on one
side or the other by great expanses of _chapada_.

Immense _bacabeira_ palms, 40 to 50 ft. high, were numerous, most
graceful to look at, with their ten or eleven huge compound leaves placed
like an open fan. Yellow filaments of some length hung in a cluster where
the petiole of the leaves met.

We arrived at a _pedreria_--an accumulation of rocks--extending almost
right across the stream, and which was the cause of the placidity of the
waters above it. There were two channels--one to bearings magnetic 330 deg.,
the other to 360 deg.--on either side of a central island. We followed the
first and larger channel. The island, which had a most luxuriant growth
of trees upon it, was subdivided into two by a channel 10 m. wide at its
south-eastern end.

For purposes of identification I named all the islands we saw. The larger
of these two I called Esmeralda Island. In order to establish its exact
position I landed and took observations for latitude and longitude. Lat.
13 deg. 15'.6 S.; long. 56 deg. 46' W.

[Illustration: An Island of the Arinos River.]

[Illustration: Vegetation on an Island in the River Arinos.]

We were then at an elevation of 1,150 ft. The temperature in the shade
was 77 deg. Fahr. and 98 deg. in the sun. Six-tenths of the sky was covered with
thick globular clouds, which made the air heavy, although the temperature
was not excessively high. It must be remembered that we in the canoe were
in the sun all the time and suffered a good deal in the morning and
afternoon, when the sun was not high, by the refraction of the sun'