the present.

"We are the last representatives of the human race in the Jovian
planetary system. Our every trace upon the surface has been obliterated.
We are hiding in our holes in the ground, coming out at night by stealth
so that our burrows shall not be revealed to the hexans. We are fighting
for time in which our scientists may learn the secrets of power--and
fearing, each new day, that the enemy may have so perfected their
systems of rays that they will be able to detect us and destroy us, even
in our underground and heavily shielded retreats, by means of forces
even more incomprehensible than those they are now employing.

"Therefore, friends, you see how little we are able to do for you, we
a race fighting for our very existence and doomed to extinction save
for a miracle. We cannot take you to Callisto, for it is besieged by the
hexans and the driving forces of your lifeboats, practically broadcast
as they are, would be detected and we should all be destroyed long
before we could reach safety. Captain King and I have pondered long and
have been able to see only one course of action. We are drifting at
constant velocity, using no power, and with all save the most vitally
necessary machinery at rest. Thus only may we hope to avoid detection
during the next two hours.

"Our present course will take us very close to Europa, which the hexans
believe to be like Ganymede, entirely devoid of civilized life. Its
original humanity was totally destroyed, and all its civilized hexans
are finding shelter from our torpedoes upon Jupiter until we of Callisto
shall likewise have been annihilated. The temperature of Europa will
suit you. Its atmosphere, while less dense than that to which you are
accustomed, will adequately support your life. If we are not detected
in the course of the next few hours we can probably land upon Europa in
safety, since its neighborhood is guarded but loosely. In fact, we have
a city there, as yet unsuspected by the hexans, in which our scientists
will continue to labor after Callisto's civilization shall have
disappeared. We think that it will be safe to use your power for the
short time necessary to effect a landing. We shall land in a cavern,
in a crater already in communication with our city. In that cavern,
instructed and aided by some of us, you will build a rocket vessel--no
rays can be used because of the hexans--in which you will be able to
travel to a region close enough to your earth