ing since I was knee-high. Three years ago I figured I'd
become good enough to write a book on the subject. I got more
arguments over that book--sounder arguments too, I'd say--than about
any paper I've published in physics." He looked at Barney a moment,
still seriously, and went on. "I told you wetting a line would calm me
down after that upset you gave me. Well, it has--fishing is as good a
form of therapy as I know about. Now I've been doing some thinking.
I'd be interested ... well, I'd like to talk some more about the Tube
with you, Mr. Chard. And perhaps about other things too."

"Very gratifying to hear that, doctor," Barney said gravely. "I did
regret having to upset you, you know."

McAllen shrugged. "No harm done. It's given me some ideas. We'll talk
right here." He indicated the weather-beaten little cabin on the bank
behind Barney. "I'm not entirely sure about the California place.
That's one reason I suggested this trip."

"You feel your houseman there mightn't be entirely reliable?"

"Fredericks unreliable? Heavens no! He knows about the Tube, of
course, but Fredericks _expects_ me to invent things. It wouldn't
occur to him to talk to an outsider. He's been with me for almost
forty years."

"He was," remarked Barney, "listening in on the early part of our
conversation today."

"Well, he'll do that," McAllen agreed. "He's very curious about anyone
who comes to see me. But otherwise ... no, it's just that in these
days of sophisticated listening devices one shouldn't ever feel too
sure of not being overheard."

"True enough." Barney glanced up at the cabin. "What makes you so
sure of it here, doctor?"

"No reason why anyone would go to the trouble," McAllen said. "The
property isn't in my name. And the nearest neighbor lives across the
lake. I never come here except by the Tube so I don't attract any
attention."

He led the way along the dock. Barney Chard followed, eyes
reflectively on the back of McAllen's sunburned neck and the wisps of
unclipped white hair sticking out beneath his beaked fishing cap.
Barney had learned to estimate accurately the capacity for physical
violence in people he dealt with. He would have offered long odds that
neither Dr. McAllen nor Fredericks, the elderly colored man of all
work, had the capacity. But Barney's right hand, slid idly into the
pocket of his well-tailored coat, was resting on a twenty-five caliber
revolver. This was, after all, a very unusual situati