on. The human
factors in themselves were predictable. Human factors were Barney's
specialty. But here they were involved with something unknown--the
McAllen Tube.

When it was a question of his personal safety, Barney Chard preferred
to take no chances at all.

From the top of the worn wooden steps leading up to the cabin, he
glanced back at the lake. It occurred to him there should have been at
least a suggestion of unreality about that placid body of water, and
the sun low and red in the west beyond it. Not that he felt anything
of the kind. But less than an hour ago they had been sitting in
McAllen's home in Southern California, and beyond the olive-green
window shades it had been bright daylight.

"But I can't ... I really can't imagine," Dr. McAllen had just
finished bumbling, his round face a study of controlled dismay on the
other side of the desk, "whatever could have brought you to these ...
these extraordinary conclusions, young man."

Barney had smiled reassuringly, leaning back in his chair. "Well,
indirectly, sir, as the pictures indicate, we might say it was your
interest in fishing. You see, I happened to notice you on Mallorca
last month...."

* * * * *

By itself, the chance encounter on the island had seemed only
moderately interesting. Barney was sitting behind the wheel of an
ancient automobile, near a private home in which a business
negotiation of some consequence was being conducted. The business
under discussion happened to be Barney's, but it would have been
inexpedient for him to attend the meeting in person. Waiting for his
associates to wind up the matter, he was passing time by studying an
old man who was fishing from a small boat offshore, a hundred yards or
so below the road. After a while the old fellow brought the boat in,
appeared a few minutes later along the empty lane carrying his tackle
and an apparently empty gunny sack, and trudged unheedingly past the
automobile and its occupant. As he went by, Barney had a sudden sense
of recognition. Then, in a flash, his mind jumped back twelve years.

Dr. Oliver B. McAllen. Twelve years ago the name had been an important
one in McAllen's field; then it was not so much forgotten as
deliberately buried. Working under government contract at one of the
big universities, McAllen had been suddenly and quietly retired.
Barney, who had a financial interest in one of the contracts, had made
inquiries; he was li