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tance northward. At the place where we ceased to ascend the
stream, the Santa Cruz was almost as large as at the places
where we passed the first and second nights near the estuary.
The velocity of the current was still at least six knots an hour;
though the depth remained undiminished. The temperature of
the water was 45°, while that of the air was seldom so high,
even in the day-time, and at night was usually below the freezing
point. Trees, or rather the trunks of trees, were found
lying upon the hanks, whose water-worn appearance indicated
that they had been carried far by the stream. The water
was very free from sediment, though of a whitish blue colour,
which induces me to suppose that it has been chiefiy produced
by melted snow, or that it has passed through lakes in which
the sediment it might have brought so far was deposited.
I f filled from the waters of the nearer mountains only, its
temperature would surely be lower, approaching that of melted
snow : it would also, in all probability, bring much sediment,
and would therefore be muddier, and less pure in colour.
When one considers how large an extent of country there is
between the River Negro and the Strait of Magalhaens, and
that through that extensive region only one river of magnitude
flows, it may be difficult to account for the manner in which
the drainage of the eastern side of the great Cordillera is carried
off, or where the melted snow and occasional heavy rains
disappear.
The Gallegos is small, though it runs into a large estuary.
The Chupat river is very small: that at Port Desire is
scarcely more than a brook. At times, it is true, these smaller
rivers are flooded, but their floods (added to their usual streams)
seem unequal to carrying off the continual drainage of the
Andes. South of the Negro only the Santa Cruz flows with
a full and strong stream throughout the whole year, and my
idea is that the sources of the river Santa Cruz are not far
from those of the southern branch of the Negro, near the
forty-fifth degree of latitude; and that it runs at the foot of
the Andes, southward, through several lakes, until it turns to
the eastward in the parallel of fifty degrees.
VOL. II.