nches, waiting for the hiss of the bleeder valve
that would tell him that the air pressure had been raised to allow
someone to enter the air lock.

It was Morgan, the FBI man, who finally cracked the door. Griffin and
Dr. Kent were with him.

"You all right?" asked Morgan.

"I'm fine," MacHeath said, "but Bern is going to have a sore neck for
a while. I didn't hit him hard enough to break it, but he'll get
plenty of sleep before he wakes up."

More FBI men came in, and they dragged out the unprotesting Bern.

Dr. Kent said: "Well, I'm glad that's over. I'll have to get back and
see what Dr. Nordred is raving about."

"Raving?" asked MacHeath innocently.

"Yes. While I was in the pump room reducing the pressure, he called me
on the interphone. Said he'd been looking all over for me. He and
Luvochek and Bessermann are up in the lab." He frowned. "They claim
that one of the radiolead samples was floating in the air in the lab.
It's settled down now, I gather, but it only weighs a fraction of what
it should, though it's gaining all the time. And that's ridiculous.
It's not at all what Dr. Nordred's theory predicted." Then he clamped
his lips together, thinking perhaps he had talked too much.

"Interesting," said MacHeath blandly. "Very interesting."

* * * * *

Senator Gonzales sat in Brian Taggert's sixth-floor office in the
S.M.M.R. building and looked puzzled. "All right, I grant you that
Bern couldn't have been the saboteur. Then why arrest him?"

Dave MacHeath took a drag from his cigarette before he answered. "We
had to have a patsy--someone to put the blame on. No one really
believed that it was just bad luck, but they'll all accept the idea
that Bern was a saboteur."

"We would have had to arrest him eventually, anyway," said Brian
Taggert.

"Give me a quick run-down," Gonzales said. "I've got to explain this
to the President."

"Did you ever hear of the Pauli Effect?" MacHeath asked.

"Something about the number of electrons that--"

"No," MacHeath said quickly. "That's the Pauli _principle_, better
known as the Exclusion Principle. The Pauli _Effect_ is a different
thing entirely, a psionic effect.

"It used to be said that a theoretical physicist was judged by his
inability to handle research apparatus; the clumsier he was in
research, the better he was with theory. But Wolfgang Pauli was a lot
more than clumsy. Apparatus would break, topple over, go to pieces,