the pilot.

He swung in nearer where the dead man lay. Joe had a sickening idea of
who the dead man might be. A sudden rush of noise in the headphones and
he pushed the button again.

"Reel in now!" shouted the pilot. "Our job's done."

Joe reeled in as the plane winged steadily back toward the Shed. There
were puffs of smoke floating in the air behind. They had been ranged on
at the instant they appeared. Somebody back at the Shed knew that
something that needed to be investigated was at a certain spot, and the
two later puffs of smoke had said that radioactivity was notable in the
air along the line the two puffs made. Not much more information would
be needed. The meaning of Braun's warning that his tip was "hot" was
definite. It was "hot" in the sense that it dealt with radioactivity!

The plane dipped down and landed by the great doors again. It taxied up
and the pilot killed the motor.

"We've been using Geigers for months," he said pleasedly, "and never got
a sign before. This is one time we were set for something."

"What?" asked Joe. But he knew.

"Atomic dust is one good guess," the pilot told him. "It was talked of
as a possible weapon away back in the Smyth Report. Nobody's ever tried
it. We thought it might be tried against the Platform. If somebody
managed to spread some really hot radioactive dust around the Shed, all
three shifts might get fatally burned before it was noticed. _They'd_
think so, anyhow! But the guy who was supposed to dump it opened up the
can for a look. And it killed him."

He climbed out of the plane and went to the doorway. He took a telephone
from a guard and talked crisply into it. He hung up.

"Somebody coming for you," he said amiably. "Wait here. Be seeing you."

He went out, the motor kicked over and caught, and the tiny plane raced
away. Seconds later it was aloft and winging southward.

Joe waited. Presently a door opened and something came clanking out. It
was a tractor with surprisingly heavy armor. There were men in it, also
wearing armor of a peculiar sort, which they were still adjusting. The
tractor towed a half-track platform on which there were a crane and a
very considerable lead-coated bin with a top. It went briskly off into
the distance toward the north.

Joe was amazed, but comprehending. The vehicle and the men were armored
against radioactivity. They would approach the dead man from upwind, and
they would scoop up his body and put it in the lead-li