During this brief period the Astronef had recrossed the orbits of the Earth and Mars and had passed through that marvellous region of the Solar System, the Belt of the Asteroides. Nearly a hundred million miles of their journey had lain through this zone in which hundreds and possibly thousands of tiny planets revolve in vast orbits round the Sun.
Then had come a world less void of over three hundred million miles, through which they voyaged alone, surrounded by the ever-constant splendours of the heavens, and visited only now and then by one of those Spectres of Space, which we call comets.
Astern the disc of the Sun steadily diminished and ahead the grey-blue shape of Jupiter, the Giant of the Solar System, had grown larger and larger until now they could see it as it had never been seen before—a gigantic three-quarter moon filling up the whole heavens in front of them almost from zenith to nadir. Three of its satellites, Europa, Ganymede, and Calisto, were distinctly visible even to the naked eye, and Europa and Ganymede, happened to be in such a position in regard to the Astronef that her crew could see not only the bright sides turned towards the Sun, but also the black shadow-spots which they cast on the cloud-veiled face of the huge planet. Calisto was above the horizon hanging like a tiny flicker of yellowish-red light above the rounded edge of Jupiter, and Io was invisible behind the planet.
"Five hundred million miles!" said Zaidie, with a little shiver; "that seems an awful long way from home—I mean America—doesn't it? I often wonder what they are thinking about us on the dear old Earth. I don't suppose any one ever expects to see us again. However, it's no good getting homesick in the middle of a journey when you're outward bound. And now what is the programme as regards His Majesty King Jove? We shall visit the satellites of course?"
"Certainly," replied Redgrave; "in fact, I shouldn't be surprised if our visit was confined to them."
"What! do you mean to say we shan't land on Jupiter after coming nearly six hundred million miles to see him? That would be disappointing. But why not? don't you think he's ready to be visited yet?"
"I can't say that, but you must remember that no one has the remotest notion of what there is behind the clouds or whatever they are which form those bands. All we really know about Jupiter is that he is of enormous size, for instance, he's over twelve hundred times bigger than the Earth and that his density isn't much greater than that of water—and my humble opinion is that if we're able to go through the clouds without getting the Astronef red-hot we shall find that Jupiter is in the same state as the Earth was a good many million years ago."
"I see," said Zaidie, "you mean just a mass of blazing, boiling rock and metal which will make islands and continents some day; and that what we call the cloud-bands are the vapours which will one day make its seas. Well, if we can get through these clouds we ought to see something worth seeing. Just fancy a whole world as big as that all ablaze like molten iron! Do you think we shall be able to see it, Lenox?"
"I'm not so sure about that, little woman. We shall have to go to work rather cautiously. You see Jupiter is far bigger than any world we've visited yet, and if we got too close to him the Astronef's engines might not be powerful enough to drive us away again. Then we should either stop there till the R. Force was exhausted or be drawn towards him and perhaps drop into an ocean of molten rock and metal."
"Thanks!" said Zaidie, with a shrug of her shapely shoulders. "That would be an ignominious end to a journey like this, to say nothing of the boiling oil part of it; so I suppose you'll make stopping-places of the satellites and use their attraction to help you to resist His Majesty's."