But it's adjusted for Martian gravity. You'll get along, but
it wouldn't be so easy for me with Earth gravity. I'd have to wear the
portable G-ray all the time, and that's not so comfortable. All right
with you?"

"Oh, certainly. I didn't understand."

* * * * *

Carr saw that his friend had unstrapped the black box from his
shoulders. He didn't blame him. Glad he wasn't a Martian. It was
mighty inconvenient for them on Venus or Terra. Their bodies, large
and of double the specific gravity, were not easily handled where
gravity was nearly three times their own. The Venusians and
Terrestrials were more fortunate when on Mars, for they could become
accustomed to the altered conditions. Only had to be careful they
didn't overdo. He remembered vividly a quick move he had made on his
first visit to Mars. Carried him twenty feet to slam against a granite
pedestal. Bad cut that gave him, and the exertion in the rarefied
atmosphere had him gasping painfully.

He walked to one of the ports and peered through its thick window.
Mado was fussing with the controls. The velvety blackness of the
heavens; the myriad diamond points of clear brilliance. Cold, too, it
looked out there, and awesomely vast. The sun and Earth had been left
behind and could not be seen. But Carr didn't care. The heavens were
marvelous when viewed without the obstruction of an atmosphere. But
he'd seen them often enough on his many business trips to Mars and
Venus.

"Ready for bed?" Mado startled him with a tap on the shoulder.

"Why--if you say so. But you haven't shown me through the _Nomad_
yet."

"All the time in the universe for that. Man, don't you realize you're
free? Come, let's grab some sleep. Need it out here. The ship'll be
here when we wake up. She's flying herself right now. Fast, too."

Carr looked at the velocity indicator. Seven hundred miles a second
and still accelerating! He felt suddenly tired and when Mado opened
the door of a sleeping cabin its spotless bunk looked very inviting.
He turned in without protest.

CHAPTER III

_A Message_

The days passed quickly, whether measured by the Martian chronometer
aboard the _Nomad_ or by Carr's watch, which he was regulating to
match the slightly longer day of the red planet. He was becoming
proficient in the operation of all mechanisms of the ship and had
developed a fondness for its every appointment.

Behind them the sun was losing much of its