more than this--for after all they could not
only see the Worlds of Space for themselves, but circumnavigate them if
they chose.

During their stay they were shown on these same screens the pictorial
history of the world whose guests they were. These pictures, which they
recognised as an immeasurable development of what is called the
cinematograph process on Earth, extended through the whole gamut of the
satellite's life. They formed, in fact, the means by which the children
of Ganymede were taught the history of their world.

It was, of course, inevitable that the _Astronef_ should prove an object
of intense interest to their hosts. They had solved the problem of the
Resolution of Forces, as Professor Rennick had done, and, as they were
shown pictorially, a vessel had been made which embodied the principles
of attraction and repulsion. It had risen from the surface of Ganymede,
and then, possibly because its engines could not develop sufficient
repulsive force, the tremendous pull of the giant planet had dragged it
away. It had vanished through the cloud-belts towards the flaming
surface beneath--and the experiment had never been repeated.

Here, however, was a vessel which had actually, as Redgrave had
convinced his hosts by means of celestial maps and drawings of his own,
left a planet close to the Sun, and safely crossed the tremendous gulf
of six hundred and fifty million miles which separated Jupiter from the
centre of the system. Moreover, he had twice proved her powers by taking
his host and two of his newly-made friends, the chief astronomers of
Ganymede, on a short trip across Space to Calisto and Europa, the second
satellite of Jupiter, which, to their very grave interest, they found
had already passed the stage in which Ganymede was, and had lapsed into
the icy silence of death.

It was these two journeys which led to the last adventure of the
_Astronef_ in the Jovian System. Both Redgrave and Zaidie had
determined, at whatever risk, to pass through the cloud-belts of
Jupiter, and catch a glimpse, if only a glimpse, of a world in the
making. Their host and the two astronomers, after a certain amount of
quiet discussion, accepted their invitation to accompany them, and on
the morning of the eighth day after their landing on Ganymede, the
_Astronef_ rose from the plain outside the Crystal City, and directed
her course towards the centre of the vast disc of Jupiter.

She was followed by the telescopes of