, for they must travel light years; but
now this sun was coming toward them, and already was less than two
hundred and fifty billion miles away!

They would pass that other star in about seventy years. That was
scarcely more than a third of a man's lifetime. They could make the
journey with conceivable speeds--but in that brief period they must
prepare to move!

The swift agitation for action had met with terrific resistance. They
were satisfied; why move?

But, while some men had devoted their time to arousing the people to
help, others had begun doing work that had not been done for a long,
long time. The laboratories were reopened, and workshops began humming
again. They were making things that were new once more, not merely
copying old designs.

Their search had been divided into sections, search for weapons with
which to defend themselves in case they were attacked, and search for
the basic principles underlying the operation of their space ships. They
had machines which they could imitate, but they did not understand them.
Success had been theirs on these quests. The third section had been less
successful. They had also been searching for secrets of the apparatus
their forefathers had used to swing the planets in their orbits, to move
worlds about at will. They had wanted to be able to take not only their
space ships, but their planets as well, when they went to settle on
these other worlds and in this other solar system.

But the search for this secret had remained unrewarded. The secret of
the spaceships they learned readily, and Taj Lamor had designed these
mighty ships below there with that knowledge. Their search for weapons
had been satisfied; they had found one weapon, one of the deadliest that
their ancestors had ever invented. But the one secret in which they were
most interested, the mighty force barrage that could swing a world in
its flight through space, was lost. They could not find it.

They knew the principles of the driving apparatus of their ships, and it
would seem but a matter of enlargement to drive a planet as a ship, but
they knew this was impossible; the terrific forces needed would easily
be produced by their apparatus, but there was no way to apply them to a
world. If applied in any spot, the planet would be torn asunder by the
incalculable strain. They must apply the force equally to the entire
planet. Their problem was one of application of power. The rotation of
the planet made