e. For hours they sat almost silent at their telescopes, trying to
probe the mystery which has baffled human science since the days of
Galileo, and gradually it became plain that Redgrave was correct in the
hypothesis which he had derived from Flammarion and one or two others of
the more advanced astronomers.

"I believe I was right, or, in other words, those that I got the idea
from are," he said, as they approached the orbit of Calisto, which
revolves at a distance of about eleven hundred thousand miles from the
surface of Jupiter.

"Those belts are made of clouds or vapour in some stage or other. The
highest--the ones along the Equator and what we should call the
Temperate Zones--are the highest, and therefore coolest and whitest. The
dark ones are the lowest and hottest. I daresay they are more like what
we should call volcanic clouds. Do you see how they keep changing?
That's what's bothered our astronomers. Look at that big one yonder a
bit to the north, going from brown to red. I suppose that's something
like the famous red spot which they have been puzzling about. What do
you make of it?"

"Well," said Zaidie, looking up from her telescope, "it's quite certain
that the glare must come from underneath. It can't be sunlight, because
the poor old Sun doesn't seem to have strength enough to make a decent
sunset or sunrise here, and look how it's running along to the westward!
What does that mean, do you think?"

"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