ow about the second?" Strong interrupted quickly,
remembering Connel's admonition about keeping the incident quiet.

"I was ordered to go over the graphs again, to look for any possible
clue in a worker's mental make-up that would lead him to a criminal
act." She paused and looked up at him squarely. "Do you suspect me too?"

"I'm sorry, Joan," said the young captain. "But this whole business is
getting me down. Tom, disappearing on Mars, Roger and Astro walking off
guard duty and stealing a scout, and now this latest sabotage attempt."
He sighed and shook his head. "I'm tired I guess."

She smiled. "I understand, Steve, and regardless of what Major Connel
and Commander Walters have said, I'll bet my last credit there's a good
reason for what the boys have done."

Strong looked down at the pretty physicist and smiled. "Thanks, Joan,"
he said. "Now, what about these papers?"

"It's about the report on Pat Troy," she replied. "When we asked him if
he was working with anyone other than the professor, he lied."

She produced a sheet of paper from among those she held and handed it to
Strong. The young captain took it and scanned it quickly. The paper was
ordinary graph paper with a series of small, wavy lines on it in red
ink. Near the bottom of the paper, there was a jagged peak in the wavy
line. "What does this mean?" he asked, pointing to the peak.

"That was his reaction when he was asked if he worked for anyone else."

"Does that mean it's a lie?"

"Yes. All the waves that you see," she continued, pointing to the line,
"represent answers to questions about his personal life. Does he shave
in the morning? Does he brush his teeth at night, and so forth. They're
comparison questions to show his reaction when he tells the truth. That
peak indicates a lie."

"Then," said Strong thoughtfully, "he might be the saboteur."

"Or know who it is," said Joan.

"I've got to get this information to Connel right away!" said Strong.
"Can I have this paper?"

"Yes. I made copies. I was just going to take one to the commander when
I saw you."

"I'll try to locate Major Connel and you go on and tell the commander
what you've found. And Joan--" Strong hesitated.

"Yes?"

"Put in a good word for the cadets, will you?" Strong pleaded. "Both
Connel and Commander Walters are all set to blast them right out of the
service."

"I'll do what I can--" Suddenly Dr. Dale stopped, her eyes widening with
fright. She pointed down th