or
his own sake as for anyone else's.

* * * * *

"That's the problem," the chief continued. "Essentially an
indestructible machine with a built-in source of power that one can't
reach. It had to be built that way--a war instrument, you know."

He stopped and looked squarely at the bright young man sitting across
the desk. "This lousy war. You'd think the human race would grow up some
time, wouldn't you?" He filled a pipe with imported Earth tobacco and
lit it, and took a few deep puffs. "There's something else. I don't know
how they do it, but they can communicate with one another over long
distances. That made them very useful for military purposes.

"They are loyal to one another, too. They try to protect each other and
keep one another from being captured. Do you find that surprising?"

The question caught Jordan unprepared. "Well, yes. It is, kind of--" he
said. "They are only machines."

The chief closed his eyes for a moment. He seemed tired.

"Yes," he repeated, "they are only machines. Anyway, we don't know
everything about them, even yet. There are still a few secret angles, I
think. The men who could tell us are either dead or in hiding.

"There's one fact though that gives us a great advantage. Their
brain"--he stopped on the word and considered it--"I mean their thinking
apparatus gives off a very penetrating short-wave length radiation which
you can pick up on your meters anywhere in a radius of two thousand
miles, and you can locate the source accurately if you get within fifty
miles.

"The only real problem you'll have in finding them is the confusion
created by illegal atomic piles. You'd be surprised how many of them we
have turned up recently. They are owned by private parties and are run
illegally to keep from paying the tax on sources of power. You have to
track those down, but once you get them labeled it will be clear
sailing."

He stopped to take a few puffs on his pipe.

"Don't try to be a hero," he said after a few moments. "Don't get close
to the thing you are hunting. None of them yet has injured any of us,
but if one should want to, he could crush you to death with two
fingers. Use the permallium nets and net bombs if you locate him."

He tamped his pipe out. "Well, that's it," he said.

The new man arose. "I want you to know that I appreciate the trust you
have put in me."

"Sure, sure," the chief said, but it was not unfriendly. "Do you like