the side of
the hill and conceal the ship, and then followed the doctor. In the
cave the door was shut and the doctor placed against the wall under
the window through which he had peered earlier in the night. Slavatsky
took his seat at the table, his malignant black eyes boring into the
Doctor. Carson and Willis sat on the edge of the operating table,
evidently still partially under the effects of the anesthetic that had
been administered to them.

"How did you get back here?" demanded Slavatsky.

"Find out!" snapped Dr. Bird.

The dwarf rose threateningly.

"Speak respectfully to me; I am the Master of the World!" he roared in
an angry voice. "Answer my questions when I speak, or means will be
found to make you answer. How did you get back here?"

Dr. Bird maintained a stubborn silence, his fierce eyes answering the
dwarf's, look for look, and his prominent chin jutting out a little
more squarely. Carson suddenly broke the silence.

"That's not the Bird we had here earlier," he cried as he staggered to
his feet.

"What do you mean?" demanded Slavatsky whirling on him.

"Look at his hands!" replied Carson pointing.

* * * * *

Slavatsky looked at Dr. Bird's long mobile fingers and an evil leer
came over his countenance.

"So, Dr. Bird," he said slowly, "you thought to match wits with Ivan
Slavatsky, the greatest mind of all the ages. For a time you fooled me
when your double was operated on here, but not for long. I presume you
thought that we had no way of detecting the substitution? You have
discovered differently. Where is your friend, Mr. Carnes?"

"Didn't your men leave him in the cabin when you kidnapped me?"

Slavatsky looked at Frink inquiringly.

"He stayed in the cabin if he was in it when we got there," the leader
of the kidnapping gang replied. "He got a full shot of lethane and
he's due to be asleep yet. I don't know how this man recovered. I left
him there myself."

"Fool!" shrieked Slavatsky. "You brought me a double, a dummy whom I
wasted my time in operating on. Was the other a dummy, too?"

"I didn't enter the cabin."

Slavatsky shrugged his shoulders.

"If that is all the good the menthium I have injected has done you, I
might as well have saved it. It doesn't matter, however: we have the
one we wanted. Dr. Bird, it was very thoughtful of you to come here
and offer your marvelous brain to strengthen mine. I have no doubt
that you will yield even