h. But bear in mind that this is simply the most
trifling application of my discovery. I could use it for separating
U-235 from U-238 just as easily. In fact, I already--" He stopped in
mid-sentence, cocked his head, looked at me and backtracked. "Never
mind that. But you know what a Maxwell demon is?"

"No."

"Good for you, Virgie. Good for you!" he applauded. "I knew I'd get
the truth out of you if I waited long enough." _Another_ ambiguous
remark, I thought to myself. "But you surely know the second law of
thermodynamics."

"Surely."

"I thought you'd say that," he said gravely. "So then you know that if
you put an ice cube in a glass of warm water, for instance, the ice
melts, the water cools, and you get a glass with no ice but with all
the water lowered in temperature. Right? And it's a one-way process.
That is, you can't start with a glass of cool water and, hocus-pocus,
get it to separate into warm water and ice cube, right?"

"Naturally," I said, "for heaven's sake. I mean that's silly."

"_Very_ silly," he agreed. "You know it yourself, eh? So watch."

He didn't say hocus-pocus. But he did adjust something on one of his
gadgets.

There was a faint whine and a gurgling, spluttering sound, like fat
sparks climbing between spreading electrodes in a Frankenstein movie.

The water began to steam faintly.

But only at one end! That end was steam; the other was--was--

It was ice. A thin skin formed rapidly, grew thicker; the other open
end of the U-tube began to bubble violently. Ice at one end, steam at
the other.

Silly?

But I was seeing it!

I must say, however, that at the time I didn't really know that that
was all I saw.

* * * * *

The reason for this is that Pudge Detweiler came groaning down the
steps to the laboratory just then.

"Ah, Greek," he wheezed. "Ah, Virgie. I wanted to talk to you before I
left." He came into the room and, panting, eased himself into a chair,
a tired hippopotamus with a hangover.

"What did you want to talk to me about?" Greco demanded.

[Illustration]

"You?" Pudge's glance wandered around the room; it was a look of
amused distaste, the look of a grown man observing the smudgy mud play
of children. "Oh, not you, Greek. I wanted to talk to Virgie. That
sales territory you mentioned, Virgie. I've been thinking. I don't
know if you're aware of it, but when my father passed away last
winter, he left me--well, with certain r