Their air supply was excellent; the mechanism never failed in its work; certainly the air grew hot and fetid at times but by the aid of electric fans it was freshened and purified. Every day they looked out of the little glass window, and drank in the glories of the heavens.
One day, it was the ninety-eighth according to Alan’s chart, Mavis startled them all by a sudden exclamation.
“What is it, my dear?” asked Sir John, looking up from an interesting game of chess he was enjoying with Alan.
“Look at Jupiter! Isn’t he large to-night?” said she. “Why, yesterday he looked like a big star, to-day he is like the moon at harvest time.”
They all crowded round the little window.
“By Jove, you’re right,” said Alan. “We must be sailing in a direct line toward him.”
“How plain the clouds are upon him,” said Desmond. “You can see them plainly right across his face.”
The belts across the face of Jupiter were certainly very plain; across the surface of the planet they floated pearly white, like masses of “snow-clouds” as seen in England on a hot summer’s day. From the equatorial region they merged, both north and south from a glorious coppery colour, becoming a deep, ruddy purplish tint at the poles.
“Are they clouds like ours?” asked Mavis wonderingly.
“I don’t think it has ever been proved what they really are,” answered Alan. “I think the general theory is, that those clouds as you call them are, in reality, a vapour-laden atmosphere that floats across the orb.”