ing burned, which would keep them from responding properly. By
rerouting the current around each relay, Arcot checked them one by one.

It was just as they had finished testing the last one that Fuller
yelled.

"Hey! _Look!_" He pointed out the broad viewport in the side of the
ship.

Far off to their left and far to their right, they saw two shining ships
paralleling their course. They were shining, sleek ships, their long,
longitudinal windows glowing with white light. They seemed to be moving
at exactly the same speed, holding grimly to the course of the _Ancient
Mariner_. They bracketed the ship like an official guard, despite the
terrific velocity of the Earthmen's ship.

Arcot stared in amazement, his face suddenly clouded in wonder. Morey,
who had come up from the power room, stared in equal wonder.

Quickly, Wade and Fuller slid into the ray control seats. Their long
practice with the rays had made them dead shots, and they had been
chosen long before as the ship's official ray operators.

"Lord," muttered Morey as he looked at the ships, "where can they have
come from?"

VII

Silently, the four men watched the two ships, waiting for any hostile
movement. There was a long, tense moment, then something happened for
which three of them were totally unprepared.

Arcot burst into sudden laughter.

"Don't--ho--hoh-ho--oh--don't shoot!" he cried, laughing so hard it was
almost impossible to understand him. "Ohoh--space--curved!" he managed
to gasp.

For a moment more, Morey looked puzzled--then he was laughing as hard as
Arcot. Helplessly, Wade and Fuller looked at them, then at each other.
Then, suddenly, Wade caught the meaning of Arcot's remark and joined the
other two in laughter.

"All right," said Fuller, still mystified, "when you half-witted
physicists recover, please let me in on the joke!" He knew it had
something to do with the mysterious ships, so he looked closely at them
in hopes that he would get the point, too. When he saw it, he blinked in
amazement. "Hey! What is this? Those ships are exact duplicates of the
_Ancient Mariner_!"

"That--that's what I was laughing at," Arcot explained, wiping his eyes.
"Four big, brave explorers, scared of their own shadows!"

"The light from our own ship has come back to us, due to the intense
curvature of the space which encloses us. In normal space, a light ray
would take hundreds of millions of years to travel all the way around
the Unive