"I may be ignorant," said Sam, "but I'm not stupid. What about it?"

Olcott glanced at Dr. Larchmont. The little scientist was beaming.

"Definitely," he said. "I want Mr. Bending to show me how he managed to dope that thing out. And, to be perfectly frank, there are a couple of things in there that I don't get at all."

"That's understandable," said Dr. Vanderlin. "We only had a few hours to look at the thing. Still, I must admit it's a lulu."

"That's not what I meant," Larchmont said. "There are some things in there that would take a long time to figure out without an explanation.

I'll admit that--"

"Wait a minute," Bending interrupted. "You said 'a few hours', Dr.

Vanderlin. You mean only since this morning?" He grinned. "What happened to the one you got Friday night? Did my fusing device work the first time?"

Vanderlin looked puzzledly at Larchmont. Larchmont said wonderingly: "Friday? You mean you had _two_ pilot models?"

Olcott said: "Where was the other? We checked your power drain and saw you weren't using any at your house, so--"

"I had three models," Bending said. "I've got one left in my car; you took one from my house, and the third was taken from my lab sometime Friday night. Somebody has it ..."

Condley said: "Dr. Artomonov, do you know anything about this?"

The Russian shook his head. "Nothing." He looked plainly frightened. "I a.s.sure you, my government knew nothing of this."

Condley leaped to his feet, said: "Where are those FBI men?" and ran out the door.

"The black market," said Bending softly. "They found out somehow."

"And they've had three days to study it," Larchmont said. "It's too late now. That thing is probably somewhere in South America by this time."

Artomonov stood up, his face oddly pale. "You must excuse me, gentlemen.

I must get in touch with Moscow immediately." He strode out of the room.

The four men remaining in the room just stared at each other for a long moment. There wasn't much else they could do.

THE END