only for logs or objects moving in one direction. The surface of the
river was soon on an average fifty feet below the edge of the banks,
this depression being one result of the water's rapid motion and
weight, which facilitated the carving of its channel.

When they had followed up the river about sixty miles towards its
source they came upon what at first had the appearance of an ocean.
They knew, however, from its elevation, and the flood coming from it,
that the water must be fresh, as they soon found it was. This lake was
about three hundred miles wide, and stretched from northeast to
southwest. There was rolling land with hills about its shores, and the
foliage on the banks was a beautiful shade of bluish purple instead of
the terrestrial ubiquitous green.

When near the great lake's upper end, they passed the mouth of a river
on their left side, which, from its volume, they concluded must be the
principal source, and therefore they determined to trace it. They
found it to be a most beautiful stream, averaging two and a half miles
in width, evidently very deep, and with a full, steady current. After
proceeding for several hours, they found that the general placidity
grew less, the smooth surface occasionally became ruffled by projecting
rocks and rapids, and the banks rose till the voyagers again found
themselves in a ravine or canon.

During their sojourn on Jupiter they had had but little experience with
the tremendous winds that they knew, from reason and observation, must
rage in its atmosphere. They now heard them whistling over their
heads, and, notwithstanding the protection afforded by the sides of the
canon, occasionally received a gust that made the Callisto swerve.
They kept on steadily, however, till sunset, at which time it became
very dark on account of the high banks, which rose as steeply as the
Palisades on the Hudson to a height of nearly a thousand feet. Finding
a small island near the eastern bank, they were glad to secure the
Callisto there for the night, below the reach of the winds, which they,
still heard singing loudly but with a musical note in what seemed to
them like the sky.

"It is incomprehensible to me." said Ayrault, as they sat at dinner,
"how the sun, at a distance of four hundred and eighty-three million
miles, can raise the amount of water we have here passing us, and
compared with which the discharge of the greatest river on earth would
be insignificant, to say noth