ng more except the natural uncertainty of nature.'"

"Try it out, your math might be wrong somewhere."

Kendall laughed. "If it was--I'd hate to try it out. If it wasn't I'd
have no reason to. And there's plenty of other work to do. For one
thing, getting that apparatus in production. The IP board won't like
me." Kendall smiled.

"They don't," replied McLaurin. "They're getting more and more and more
worried--but they've got to keep the IP fleet in such condition that it
can at least catch an up-to-date freighter."

* * * * *

Gresth Gkae looked back at Sthor rapidly dropping behind, and across at
her sister world, Asthor, circling a bare 100,000 miles away. Behind his
great interstellar cruiser came a long line of similar ships. Each was
loaded now not with instruments and pure scientists, but with weapons,
fuel and warriors. Colonists too, came in the last ships. One hundred
and fifty giant ships. All the wealth of Sthor and Asthor had been
concentrated in producing those great machines. Every one represented
nearly the equivalent of thirty million Earth-dollars. Four and a half
billions of dollars for mere materials.

Gresth Gkae had the honor of lead position, for he had discovered the
planets and their stable, though tiny, sun. Still, Gresth Gkae knew his
own giant Mira was a super-giant sun--and a curse and a menace to any
rational society. Our yellow-white sun (to his eyes, an almost invisible
color, similar to our blue) was small, but stable, and warm enough.

In half an hour, all the ships were in space, and at a given signal, at
ten-second intervals, they sprang into the superspeed, faster than
light. For an instant, giant Mira ran and seemed distorted, as though
seen through a porthole covered with running water, then steadied,
curiously distorted. Faster than light they raced across the galaxy.

Even in their super-fast ships, nearly three and a half weeks passed
before the sun they sought, singled itself from the star-field as an
extra bright point. Two days more, and the sun was within planetary
distance. They came at an angle to the plane of the ecliptic, but they
leveled down to it now, and slanted toward giant Jupiter and Jovian
worlds. Ten worlds, in one sweep, it was--four habitable worlds. The
nine satellites would be converted into forts at once, nine
space-sweeping forts guarding the approaches to the planet. Gresth Gkae
had made a fairly good search of the wo