ships and computer. He checks computations
made by astronomers stationed in floating observatories, and
after he has located any trouble and suggests a plan for
minimizing the hazards of the trip from the earth to Mars he
reports his findings and suggestions to Mr. Newton, chief of
the Interplanetary Corporation.

Stevens then takes Nadia, Mr. Newton's beautiful young daughter,
on a specially conducted sight-seeing tour of the _Arcturus_
and thoroughly explains to her all of the works of the vessel.
Nadia has herself had a good science education. While they
are down at the bottom of the ship--nearing the end of their
tour--Stevens feels a barely perceptible movement of the vessel
from its course. When he turns on the visiplate, he is horrified
to find that a mysterious ray of unparalleled power has neatly
sliced the _Arcturus_ in several places.

Nadia and Stevens are completely separated from the rest of the
crew and passengers of the ship, so they get into a lifeboat,
which is equipped for a limited amount of space travel. Despite
the strict and apparently effective vigilance of the enemy
destroyer, Stevens and Nadia make their getaway in the lifeboat,
which they aptly call "Forlorn Hope," and finally make a safe
landing on Ganymede, where Stevens almost completes a power-plant
and a radio transmitter, to enable him to communicate with the
earth or with the IPV _Sirius_, which is used by Westfall and
Brandon (two of the world's best scientists) as a floating
laboratory.

They start for Cantrell's Comet, where Stevens acquires the
necessary material for his giant transmitting tube, heads back
to Ganymede, when their ship is cut, top and bottom, by a strong
ray-beam. Stevens and Nadia soon find that the other ship is
manned by friendly beings from Saturn. Together they plan against
their common foes--the Hexans--who are enemies of the universe.
After helping the Saturnians to repair their power plant, they
start back to Ganymede, aided by their new friends from the
frigid civilization. Finally, however, Stevens succeeds in
connecting, by radio, with the _Sirius_ and his scientist friends
on board it, who rush to the aid of the two castaways. It is
while the castaways are captives of the Hexans that help looms
near.

CHAPTER IX

The _Sirius_ Takes a Hand