"Oh, indeed! Well, I'm very glad that it's five or six hundred million miles from the Earth. A dead world bigger than the Moon, and made of gold and silver sponge, wouldn't be a nice thing to have too near the Earth. There's trouble enough about that sort of thing at home as it is. Still, it'll be a nice addition to the museum, and if you'll put it away and go and wash your hands lunch will be ready."
When they got back to the deck-chamber Calisto was already a half moon in the upper sky nearly five hundred thousand miles away, and the full orb of Ganymede, shining with a pale golden light, lay outspread beneath them. A thin, bluish-grey arc of the giant planet overarched its western edge.
"I think we shall find something like a world here," said her ladyship, when she had taken her first look through her telescope; "there's an atmosphere and what look like thin clouds. Continents and oceans too, or something like them, and what is that light shining up between the breaks? Isn't it something like our Aurora?"
"It might be," replied Redgrave, turning his own telescope towards the northern pole of Ganymede, "though I never heard of a satellite having an aurora. Perhaps it's the Sun shining on the ice."
As the Astronef fell towards the surface of Ganymede she crossed his northern pole, and the nearer they got the plainer it became that a light very like the terrestrial Aurora was playing about it, illuminating the thin, yellow clouds with a bluish-violet light, which made magnificent contrasts of colouring amongst them.
"Let us go down there and see what it's like," said Zaidie. "There must be something nice under all those lovely colours."
Redgrave checked the R. Force and the Astronef fell obliquely across the pole towards the equator. As they approached the luminous clouds Redgrave turned it on again, and they sank slowly through a glowing mist of innumerable colours, until the surface of Ganymede came into plain view about ten miles below them.
What they saw then was the strangest sight they had beheld since they had left the Earth. As far as their eyes could reach the surface of the Ganymede was covered with vast orderly patches, mostly rectangular, of what they at first took for ice, but which they soon found to be a something that was self-illuminating.
"Glorified hot-houses, as I'm alive," exclaimed Redgrave. "Whole cities under glass, fields, too, and lit by electricity or something very like it. Zaidie, we shall find human beings down there."
"Well, if we do I hope they won't be like the half-human things we found on Mars! But isn't it all just lovely! Only there doesn't seem to be anything outside the cities, at least nothing but bare, flat ground with a few rugged mountains here and there. See, there's a nice level plain there near the big glass city, or whatever it is. Suppose we go down there."