harley Brett who followed him out of the room. Brett was adjusting his
oxygen mask with one hand and gripping a paralo-ray gun tightly with the
other.

"Never mind the cracks," snapped Brett, his voice muffled by the mask.
"I tell you I heard someone moving around in here."

Miles laughed again and walked straight to the middle of the room. With
their backs pressed to the wall beside the door, Tom and Astro saw Miles
bend over and lift a trap door in the middle of the floor.

The two men flashed a light down into the opening and climbed down,
pulling the trap door closed after them.

No sooner was it shut than Tom and Astro jumped forward to examine it
cautiously. Astro started to pull it open but Tom held out a warning
hand. He turned and pointed toward the room that Miles and Brett had
left. Astro nodded and they walked quickly back to the door. Sliding it
open, they stepped inside.

"By the rings of Saturn!" cried Astro.

"Well, blast my jets!" Tom exclaimed.

The air in the room was clear, completely free of the misty whirling
methane ammonia of death that swirled around them outside. Recovering
from his surprise quickly, Astro closed the door and walked to the
center of the room, looking around curiously. Tom had already slipped
off his mask and was examining the equipment lying on the floor. Astro
bent over an oddly shaped machine that looked somewhat like an ancient
compressed-air drill, with a long bar protruding from one end. He
examined the bar closely and then turned slowly to Tom.

"Do you know what this machine is?" he asked in almost a whisper.

Tom looked at it and then shook his head.

"I haven't seen one of these since I left Venus, and then only when I
was a kid hanging around the spaceports where the space rats used to
blast off for the asteroids looking for uranium."

"You mean you hunt uranium with that thing?" asked Tom.

"No, you dig it out with this."

Tom gazed at the machine thoughtfully. "Why would it be here?" he mused.
"It's already been used," said Astro, standing up. "Look, the drill head
is dull."

"That trap door!" Tom exclaimed. "It leads to a mine. Miles and Brett
have discovered high-grade uranium right here on Titan where everyone
thought there was nothing but _crystal_!"

Astro nodded grimly. "And that isn't all. This room is free of ammonia
gas."

"But how in the star-blazing dickens can they keep it out of here when
everything else outside is flooded with it?"