a heavy casting at the center of the machine. There were
braces tying it strongly to the entire structure, braces designed to
receive and transmit a tremendous thrust.

"This is the generator. Blast expelled through the big exhaust at the
stern. These smaller exhausts go above and below--right and left at
the bow. Perfect control!"

"And you flew it here!" Jerry was still trying to grasp that
incontrovertible fact. "And you were going to take me to the moon, you
said."

He looked above him where a pale, silvery segment showed dimly in the
sky. "But why the moon?" he questioned. "Even granting that this will
fly through space...."

"It will," the other interrupted. "I tried it. Went up to better than
fifty miles."

Jerry Foster took a minute to grasp that statement, then continued:
"Granting that, why go to the moon? There is nothing there, no air to
speak of, no water! It's all known."

* * * * *

The inventor turned to face the younger man in the doorway.

"There is _nothing_ known," he stated. "The modern telescopes reach
out a million light years into space. But the one place they have
never seen--can never see--is less than two hundred and fifty thousand
miles away. The moon, as of course you know, always keeps the same
side toward us. The other side of the moon has never been seen.

"Listen," he said, and his deep-set eyes were afire with in intense
emotion. "The moon is no tiny satellite; it is a sister planet. It is
whirled on the end of a rope (we call it gravitation), swung around
and around the earth. How could there be water or anything fluid on
this side? It is all thrown to the other side by the centrifugal
force. Who knows what life is there? No one--no one! I am going to
find out."

Jerry Foster was silent. He was thinking hard. He looked about him at
the clean hills, the trees, the world he knew. And he was weighing the
secure life he knew against a great adventure.

He took one long breath of the clear air as one who looks his last at
a familiar scene. He exhaled slowly. But he stepped firmly into the
machine.

"Winslow," he said, "have you any rope handy?"

The inventor was annoyed. "Why, yes, I guess so. Why? What do you want
of it?"

"I want you to tie me up again," said Jerry Foster. "I want you to
carry me off as you planned. I want to go with you."

The tall man stared at the quiet, determined face before him. Slowly
his own strained features sm