ending them the message then returned to the
work of draining the Arctic Ocean, which, as the north pole was now
returning to the sun, was the thing to do, and the travellers resumed
their study of the heavenly bodies.

CHAPTER II.

SPACE AND MARS.

Never before had the travellers observed the stars and planets under
such favourable conditions. No air or clouds intervened, and as the
Callisto did not revolve on its axis there was no necessity for
changing the direction of the glasses. After an hour of this
interesting work, however, as it was already late at the longitude they
had left on earth, and as they knew they had many days in space before
them, they prepared to go to bed. When ready, they had only to pull
down the shades; for, as apergy was not applied to them, but only to
the Callisto, they still looked upon the floor as down, and closed the
heavy curtains to have night or darkness. They found that the side of
the Callisto turned constantly towards the sun was becoming very warm,
the double-toughened glass windows making it like a greenhouse; but
they consoled themselves with the thought that the sun's power on them
was hourly becoming less, and they felt sure the double walls and thick
upholstery would protect them almost anywhere within the solar system
from the intense cold of space.

"We could easily have arranged," said Ayrault, "for night and day on
alternate sides of the Callisto by having strips of metal arranged
spirally on the outside as on the end of an arrow. These would have
started us turning as slowly as we like, since we passed through the
atmosphere at a comparatively low rate of speed."

"I am afraid," said Cortlandt, "the motion, however slow, would have
made us dizzy. It would be confusing to see the heavens turning about
us, and it would interfere with using the glasses."

The base and one side of the Callisto had constant sunshine, while the
other side and the dome were in the blackest night. This dome, on
account of its shape, sky windows, and the completeness with which it
could be isolated, was an ideal observatory, and there was seldom a
time during their waking hours for the rest of the journey when it was
not occupied by one, two, or all the observers.

"There is something marvellous," said Cortlandt, "about the condition
of space. Its absolute cold is appalling, apparently because there is
nothing to absorb heat