formation.

He was just finishing his coffee as Bill Griffin came in the door and headed toward the table where MacHeath, Luvochek, and Bessermann were sitting.

MacHeath stood up and said: "Excuse me. I'll have to be getting some work done if you guys are ever going to get your own work done."

"Sure."

"Go ahead."

"Thanks for the coffee," MacHeath added as he moved away.

"Anytime," said Bessermann, grinning. "You guys just keep up the good work. When you fix 'em, they stay fixed. We haven't had a burnout since you came."

"Maybe you broke our statistical jinx," said Luvochek, with a chubby smile.

"Maybe," said MacHeath. "I hope so."

For some reason, the gnawing in his hunch factory became more persistent.

As he and Griffin walked toward the door, Griffin reported rapidly. "I checked everything in the gun chamber. No sign of any tampering. Everything's just as we left it. The dust film hasn't been disturbed."

"It figures," said MacHeath.

Outside, in the corridor, they met Dr. Konrad Bern hurrying toward the cafeteria. He stopped as he saw them.

"Oh, hello, Mr. MacHeath, Mr. Griffin," he said. His white-toothed smile was friendly, but both of the S.M.M.R. agents could detect the hostility that was hard and brittle beneath the surface. "I wanted to thank you for the wonderful job you've been doing."

"Why, thank you, doctor," said MacHeath honestly. "We aim to satisfy."

Bern chuckled. "You're doing well so far. Odd streak of luck we've had, isn't it? Poor Dr. Nordred has been under a terrible strain; his whole life work is tied up in this project." He made a vague gesture with one hand. "Would you care for some coffee?"

"Just had some, thanks," said MacHeath, "but we'll take a rain check."

"Fine. Anytime." And he went on into the cafeteria.

"Wow!" said Griffin as he walked on down the corridor with MacHeath. "That man is scared silly! But what an actor! You'd never know he was eating his guts out."

"Sure he's scared," MacHeath said. "With all this sabotage talk going around, he's afraid there'll be an exhaustive investigation, and he can't take that right now."

Griffin frowned. "I guess I missed that. What did you pick up?"

"He's supposed to meet a Soviet agent tonight, and he's afraid he'll be caught. He doesn't know what happened to the first three, and he won't know what will happen to Number Four tonight.

"We'll keep him around as long as he's useful. He's not a Bohr or a Pauli or a Fermi, but he—"

MacHeath stopped himself suddenly and came to a dead halt.

"My God," he said softly, "that's it."

His hunch had hatched.

After a moment, he said: "Harry is getting back from the target end of the tube now, Bill. He can't pick me up, so beetle it down to the tool room, get him, and get up to the workshop fast. If I'm not there, wait; I have a little prying to do."

"Can do," said Griffin. He went toward the elevator at an easy lope.

David MacHeath went in the opposite direction.

When MacHeath returned to the workshop which he had been assigned, Bill Griffin and Harry Benbow were waiting for him. Beside the big-muscled Griffin, Harry Benbow looked even thinner than he was. He was a good six-two, which made him a head taller than Griffin, but, unlike many tall, lean men, Benbow had no tendency to slouch; he stood tall and straight, reminding MacHeath of a poplar tree towering proudly over the countryside. Benbow was one of those rare American Negroes whose skin was actually as close to being "black" as human pigmentation will allow. His eyes were like disks of obsidian set in spheres of white porcelain, which gave an odd contrast-similarity effect when compared with Griffin's china-blue eyes.

If the average man had wanted to pick two human beings who were "opposites," he could hardly have made a better choice than Benbow and the short, thickly-built, blond-haired, pink-skinned Bill Griffin. But the average man would be so struck by the differences that he would never notice that the similarities were vastly more important.

"You look as if you'd just been kissed by Miss America," Harry said as MacHeath came through the door.

"Better than that," MacHeath said. "We've got work to do."

"What's the pitch?" Griffin wanted to know.

"Well, in the first place, I'm afraid Dr. Konrad Bern is no longer of any use to the Redford Project. We're going to have to arrest him as an unregistered agent of the Soviet Government."

"It's just as well," said Harry Benbow gently. "His research hasn't done us any good and it hasn't done the Soviets any good. The poor guy's been on edge ever since he got here. All the pale hide around this place stirs up every nerve in him."

"What got you onto this?" Griffin asked MacHeath.

"A hunch first," MacHeath said. "Then I got data to back it up. But, first ... Harry, how'd you know about Bern's reactions? He keeps those prejudices of his down pretty deep; I didn't think you could go that far."

"I didn't have to. He spent half an hour talking to me this morning. He was so happy to see a fellow human being—according to his definition of human being—that he was as easy to read as if you were doing the reading."

MacHeath nodded. "I hate to throw him to the wolves, but he's got to go."

"What was the snooping you said you had to do?" Griffin asked.

"Dates. Times. Briefly, I found that the run of accidents has been building up to a peak. At first, it was just small meters that went wrong. Then bigger, more complex stuff. And, finally, the Monster went. See the pattern?"

The other men nodded.

"You're the therapist," Griffin said. "What do you suggest?"

"Shock treatment," said David MacHeath.

Just how Dr. Konrad Bern got wind of the fact that a squad of FBI men had come to the project to arrest him that evening is something that MacHeath didn't know until later. He was busy at the time, ignoring anything but what he was interested in. It always fascinated him to watch the mind of a psychokinetic expert at work. He couldn't do the trick himself, and he was always amazed at the ability of anyone who could.

It was like watching a pianist play a particularly difficult concerto. A person can watch a pianist, see every move he is making, and why he is making it. But being able to see what is going on doesn't mean that one can duplicate the action. MacHeath was in the same position. Telepathically, he could observe the play of emotions that ran through a psychokinetic's mind—the combinations of avid desire and the utter loathing which, playing one against another, could move a brick, a book, or a Buick if the mind was powerful enough. But he couldn't do it himself, no matter how carefully he tried to follow the raging emotions that acted as two opposing jaws of a pair of tongs to lift and move the object.

And so engrossed was he with the process that he did not notice that Konrad Bern had eluded the FBI. He was unaware of what had happened until one of the Federal agents rapped loudly on the workshop door.

Almost instantly, MacHeath picked up the information from the agent's mind. He glanced at Griffin and Benbow. "You two can handle it. Be careful you don't overdo it."

Then he went to the door and opened it a trifle. "Yes?"

The man outside showed a gold badge. "Morgan, FBI. You David MacHeath?"

"Yes." MacHeath stepped outside and showed the FBI man his identification.

"We were told to co-operate with you in this Konrad Bern case. He's managed to slip away from us somehow, but we know he's still in the area. He can't get past the gate."

MacHeath let his mind expand until it meshed with that of Dr. Konrad Bern.

"There is a way out," MacHeath