gaining, but comparatively slowly," Westfall finally
reported. "They seem to be...."

"In that case we may be all x," Brandon interrupted, brandishing his
pipe vigorously. "We know that they're on a beam--apparently we're the
only ones hereabouts having cosmic power. If we can keep away from them
until their beam attenuates, we can whittle 'em down to our size and
then take them, no matter how much accumulator capacity they've got."

"But can we keep away from them that long?" asked Dol Kenor, pointedly;
and his fellow Venerian also had a question to propound:

"Would it not be preferable to lead them in a wide circle, back to a
rendezvous with the Space Fleet, which will probably be ready by the
time of meeting?"

"I am afraid that that would be useless," Westfall frowned in thought.
"Given power, that fortress could destroy the entire Fleet almost as
easily as she could wipe out the _Sirius_ alone."

"Kenor's right." Stevens spoke up from the calculator. "You're getting
too far ahead of the situation. We aren't apt to keep ahead of them long
enough to do much leading anywhere. The Titanians can hold a beam
together from Saturn to Jupiter--why can't these snake-folks?"

"Several reasons," Brandon argued stubbornly. "First place, look at the
mass of that thing, and remember that the heavier the beam the harder
it is to hold it together. Second, there's no evidence that they wander
around much in space. If their beams are designed principally for travel
upon Jupiter, why should they have any extraordinary range? I say they
can't hold that beam forever. We've got a good long lead, and in spite
of their higher acceleration, I think we'll be able to keep out of range
of their heavy stuff. If so, we'll trace a circle--only one a good deal
bigger than the one Amonar suggested--and meet the fleet at a point
where that enemy ship will be about out of power."

Thus for hours the scientists argued, agreeing upon nothing, while
the Vorkulian fortress crept ever closer. At the end of three days of
the mad flight, the pursuing space ship was in plain sight, covering
hundreds of divisions of the micrometer screens. But now the size of
the images was increasing with extreme slowness, and the scientists
of the _Sirius_ watched with strained attention the edges of those
glowing green pictures. Finally, when the pictured edges were about
to cease moving across the finely-ruled lines, Brandon cut down his
own acceleration a trifle,