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-toughene
