t it was sabotage."

"Anyone you suspect?"

"Not a living soul," replied Walters. "Every man in that hangar has been
carefully screened by our Security Section. Background, history,
everything. No, I think it really was an accident."

"Yes, sir," replied Strong, but not with the conviction he would like to
have felt.

* * * * *

Pat Troy had been Professor Hemmingwell's foreman for nearly two years.
It was his job to read the complicated blueprints and keep the
construction and installation work proceeding on schedule. Troy lacked a
formal education, but nevertheless he could read and interpret the
complicated plans which the professor and his assistants drew up, and
transform their ideas into actual mechanical devices. Professor
Hemmingwell considered himself fortunate to have a man of Troy's ability
not only as a co-worker, but as a close friend.

But Dave Barret did not like Troy, and he made this dislike obvious by
giving Troy as much work as possible, mainly tasks that were beneath his
ability, claiming he only trusted the trained scientists. Barret put the
professor in the position of having to defend one to the other. He
needed both men, both being excellent in their respective fields, and
found it more and more difficult to maintain any kind of peaceful
relationship between them. Barret, as Hemmingwell's chief assistant and
supervisor of the project, was naturally superior in rank to Troy, and
made the most of it. A placid, easy-going man, Troy took Barret's gibes
and caustic comments in silence, doing his work and getting it finished
on time. But occasionally he had difficulty in controlling his
resentment.

The day after the accident, or sabotage attempt on the firing unit, the
hangar was quiet, most of the workers still being psychographed. Troy,
one of the first to be graphed, had been detained by the technicians
longer than usual, but was now back at his bench, working on the unit.
This incident gave Barret the opportunity he was looking for, and as he
and Professor Hemmingwell strode through the hangar, he commented
casually, "I hate to say this, sir, but I don't like the way Troy has
been acting lately."

"What do you mean, Dave?" asked Hemmingwell.

"I depend a great deal on instinct," replied Barret. "And as good as
Troy's work has been, I feel the man is hiding something."

"Come now, Dave," snorted the professor. "I've known him a long time. I
think you're b