"I should say it means that some half-formed Jovian Continent has been flung sky high by a big burst-up underneath, and that's the blaze of the incandescent stuff running along. Just fancy a continent, say ten times the size of Asia, being split up and sent flying in a few moments like that. Look! there's another one to the north! On the whole, dear, I don't think we should find the climate on the other side of those clouds very salubrious. Still, as they say the atmosphere of Jupiter is about ten thousand miles thick, we may be able to get near enough to see something of what's going on. "Meanwhile, here comes Calisto. Look at his shadow flying across the clouds. And there's Ganymede coming up after him, and Europa behind him. Talk about eclipses! they must be about as common here as thunderstorms are with us." "We don't have a thunderstorm every day--at least not at home," corrected Zaidie, "but on Jupiter they must have two or three eclipses every day. Meanwhile, there goes Jupiter himself. What a difference distance makes! This little thing is only a trifle larger than our Moon, and it's hiding everything else." As she was speaking the full-orbed disc of Calisto, measuring nearly three thousand miles across, swept between them and the planet. It shone with a clear, somewhat reddish light like that of Mars. The _Astronef_ was feeling his attraction strongly, and Redgrave went to the levers and turned on about a fifth of the R. Force to avoid too sudden contact with it. "Another dead world!" said Redgrave, as the surface of Calisto revolved swiftly beneath them, "or at any rate a dying one. There must be an atmosphere of some sort, or else that snow and ice wouldn't be there, and everything would be either black or white as it was on the Moon. We may as well land, however, and get a specimen of the rocks and soil to add to the museum, though I don't expect there will be very much to see in the way of life." In another hour or so the _Astronef_ had dropped gently on to the surface of Calisto at the foot of a range of mountains crowded with jagged and splintery peaks, and a mile or two from the edge of a sea of snow and ice which stretched away in a vast expanse of rugged frozen billows beyond the horizon. Redgrave, as usual, went into the air-chamber and tried the atmosphere. A second's experience of it was enough for him. It was unbreathably thin and unbearably cold, although, when mixed with the air of the _Astronef_, it distinctly freshened it up. This proved that its composition was, or had been, fit for human respiration. "There's only one fault about it," he said, when he rejoined Zaidie in the sitting-room. "You know what the schoolboy said when he started kissing his first sweetheart, 'It takes too long to get enough of it.'" "You seem to be very fond of referring to that particular subject, Lenox." "Well, yes; to tell you the truth I am," and then he referred to it again in another form.