ey agree that they do not know all the secrets of the Universe, but
they agree that the speed of light is fixed by the nature of space."

"How fast does sound travel?" Arcot asked.

"They ask in what medium do you mean?"

"How fast does light travel? In air? In glass? The speed of light is as
variable as that of sound. If I can alter the nature of space, so as to
make the velocity of light greater, can I not then go faster than in
normal space?"

"They say that this is true," Torlos said, after more conversation with
the men at the table, "but they say that space is unalterable, since it
is emptiness."

"Ask them if they know of the curvature of space." Arcot was becoming
worried for fear his explanation would be unintelligible; unless they
knew his terms, he could not explain, and it would take a long time to
teach them.

"They say," Torlos thought, "that I have misunderstood you. They say
space could not possibly be curved, for space is emptiness, and how
could empty nothingness be curved."

Arcot turned to Morey and shrugged his shoulders. "I give up, Morey;
it's a bad case. If they insist that space is nothing, and can't be
curved, I can't go any further."

"If they don't know of the curvature of space," said Morey, "ask them
how they learned that the velocity of light is the limiting velocity of
a moving body."

Torlos translated and the scientists gave their reply. "They say that
you do not know more of space than they, for they know that the speed of
light is ultimate. They have tested this with spaceships at high speeds
and with experiments with the smallest particles of electricity."

The scientists were looking at Arcot now in protest; they felt he was
trying to foist something off on them.

Arcot, too, was becoming exasperated. "Well, if they insist that we
couldn't have come from another star, where do they think I come from?
They have explored this system and found no such people as we, so I must
have come from another star. How? If they won't accept my explanations,
let them think up a theory of their own to explain the facts!" He
paused for Torlos to translate, then went on. "They say I don't know any
more than they do. Tell them to watch this."

He drew his molecular ray pistol and lifted a heavy metal chair into the
air. Then Morey drew his heat beam and turned it on the chair. In a few
seconds, it was glowing white hot, and then it collapsed into a fiery
ball of liquid metal. Morey shut