. The main part of the stream,
however, flowed in a much larger channel between the left bank and
Elfrida Landor Island.

The joint Arinos-Juruena River had now a total width of 500 m., and
flowed in a direction of 15 deg. bearings magnetic. I took accurate
observations with the hypsometrical apparatus in order to determine the
exact elevation of that important spot: water boiled at the junction of
the Juruena and Arinos at 210 deg..43/4, while the temperature of the air was
70 deg. F.; in other words the elevation of the place was 987 ft. above the
sea level.

[Illustration: Author's Canoe going down a Cataract.]

I also took observations there for latitude and longitude. Lat. 10 deg. 21'.7
S.; long. 58 deg. 35' W. The Juruena entered the lake from bearings magnetic
250 deg. (W.S.W.), the Arinos from bearings magnetic 100 deg. (E.S.E.). The
minimum temperature during the night on Elfrida Island was 57 deg. F. My men
suffered a great deal from the cold, as they had got badly chilled
with the wet and the high wind during the day. Most of them complained of
severe rheumatic pains and violent toothache. They could not understand
why I did not have any pains of any kind--and to tell the truth, neither
could I, after all we had gone through of late.

When we left Elfrida Landor Island on July 25th we had a beautiful
stretch of river 4,000 m. long in a straight line, but with a good many
rocks strewn in the channel. The men paddled unwillingly, as they said
they were aching all over; but the current was strong and we were going
along fairly quickly. My men said that we must now have come to the end
of all the rapids. I did not care to disillusion them, although I
suspected that we still had hard days in store. We had not proceeded very
far when a rumbling noise warned us that we were approaching danger.
There was a rapid on the east side of the river, but it left a fairly
easy passage on the west. A little farther, however, we came to a very
bad rapid, and had to unload the canoe, which we were obliged to let down
carefully with ropes. My men, who felt feverish and irritable, owing to
our previous day's experience, were greatly upset at this new obstacle
facing us.

The river was 500 m. wide at this part. The rocks on which we trod when
we took the canoe down were so sharp that they cut our feet. It was not
possible to wear shoes, as when we had them on we slipped on the rock and
had no hold upon the ropes. My men, in th