s narrow prow pointed almost
directly into the zenith. Then, very slowly at first, the unimaginable
mass of the vessel floated lightly upward, with a slowly increasing
velocity. Faster and faster she flew--out beyond measurable atmosphere,
out beyond the outermost limits of the green system. Finally, in
interstellar space, Seaton threw out super-powered detector and
repelling screens, anchored himself at the driving console with a force,
set the power control at "molecular" so that the propulsive force
affected alike every molecule of the vessel and its contents, and, all
sense of weight and acceleration lost, he threw in the plunger switch
which released every iota of the theoretically possible power of the
driving mass of uranium.

Staring intently into the visiplate, he corrected their course from time
to time by minute fractions of a second of arc; then, satisfied at last,
he set the automatic forces which would guide them, temporarily out of
their course, around any obstacles, such as the uncounted thousands of
solar systems lying in or near their path. He then removed the
restraining forces from his body and legs, and with a small pencil of
force wafted himself over to Crane and the two women.

"Well, bunch," he stated, matter-of-fact, "we're on our way. We'll be
this way for some time, so we might as well get used to it. Any little
thing you want to talk over?"

"How long will it take us to catch 'em?" asked Dorothy "Traveling this
way isn't half as much fun as it is when you let us have some weight to
hold us down."

"Hard to tell exactly, Dottie. If we had precisely four times their
acceleration and had started from the same place, we would of course
overtake them in just the number of days they had the start of us, since
the distance covered at any constant positive acceleration is
proportional to the square of the time elapsed. However, there are
several complicating factors in the actual situation. We started out not
only twenty-nine days behind them, but also a matter of five hundred
thousand light-years of distance. It will take us quite a while to get
to their starting-point. I can't tell even that very close, as we will
probably have to reduce this acceleration before we get out of the
Galaxy, in order to give detectors and repellers time to act on stars
and other loose impediments. Powerful as those screens are and fast as
they work, there is a limit to the velocity we can use here in this
crowded