inferno into a heaven on earth.

My men were paddling away with great vigour and were making rapid
progress, the river flowing almost all the time northward, with
deviations of a few degrees toward the east, in stretches from 2,000 to
6,000 m. in length. We crossed an immense basin 1,500 m. broad with most
gorgeous sand beaches. Their formation in small dunes, occasionally with
an edge like the teeth of a double comb, was most interesting. Once or
twice we came to musical sands such as we had found before. Everywhere on
those beaches I noticed the wonderful miniature sand plants, of which I
made a complete collection.

As we went down we came to one or two _seringueiros_' huts, and to a
store belonging to our friend the dying Jew, who rejoiced in the name of
Moses. As he had taken all the stuff with him in the trading boat in
order to exchange it for rubber from the collectors, he had left nothing
in the store except a cheap straw hat.

As my hat by that time had lost most of its brim, and the top of it had
got loose and was moving up and down in the breeze, I thought I would not
lose the opportunity of getting new headgear. So the purchase was made
there and then, and thus fashionably attired I started once more down
stream.

We passed on the way most impressive sand banks and beaches--500, 700,
and one 1,500 m. long. The river in some spots was 1,000 m. wide. A great
island 4,000 m. in length--Bertino Miranda Island--was then passed, with
a beautiful spit of sand 15 ft. high at its southern end. Hillocks were
visible first on the left bank, then on the right. Other elongated sand
accumulations of great length were found beyond the big island, one a
huge tail of sand extending towards the north for 1,000 m. Beyond those
accumulations the river was not less than 1500 m. across, and there an
immense beach of really extraordinary beauty ran on the right side for a
length of 11/2 kil.

On that beach we halted for lunch. In the afternoon we continued, between
banks on either side of alluvial formation, principally silts and clay,
light grey in colour or white. In fact, the soil in the section directly
below the higher terrace of the great central plateau of Matto Grosso,
was formed by extensive alluvial accumulations which had made an immense
terrace extending right across all Central Brazil from west to east,
roughly speaking from the Madeira River to the Araguaya and beyond.

After we had gone some 5 kil. in a stra