pure guesswork.

* * * * *

The two scientists meant to spend the entire summer trying to solve this
riddle for all time, concentrating on it to the exclusion of everything
else. They drove west in a station wagon stuffed with equipment and
tracking a U-Haul-It packed with more.

George drove, on a road that was only two sand tracks across the wild
empty desert between Casa Grande Monument and Tonto National Monument
where cliff dwellers had lived. It was here, not far ahead, in new ruins
that were being excavated, that they hoped to solve the secret of the
exodus of the prehistoric Indians. The place was known as the Hohokam
Dig.

They topped a rise of ground and came to the site of the dig. Here the
sand tracks ended right in the middle of long trenches dug out to reveal
thick adobe walls. In the partially bared ruins the outline of a small
village could be seen; the detailed excavation would be done this summer
by workmen who would arrive from Phoenix and Tucson.

George stopped their caravan and the two men got out, stretching their
legs. They looked about, both more interested in the dig, now they were
back at it, than setting up camp. They walked around, examining various
parts of it, and the excitement of the promise of things to be
discovered in the earth came to them. "This summer we'll learn the
answer," Sidney predicted.

With skeptical hope George replied, "Maybe."

It was early afternoon when they set up camp, getting out their tent
from the U-Haul-It. They took out most of their gear, even setting up a
portable TV set run on batteries brought along. They worked efficiently
and rapidly, having done this many times before and having their
equipment well organized from long experience. By the middle of the
afternoon all was ready and they rested, sitting on folding chairs at a
small table just outside the opening of their tent.

Looking around at the dig Sidney remarked, "Wouldn't it be easy if we
could talk to some of the people who once lived here?"

"There's a few questions I'd like to ask them," said George. "I
certainly wish we had some to talk with."

He had no more than uttered this casual wish than there sounded, from
all sides of where they sat, screeching whoops. The naked brown men who
suddenly appeared seemed to materialize from right out of the
excavations. As they yelled they raised their weapons. The air was
filled, for an instant, with what looked li