iding places of the Scowrers. These four young men you
probably met last evening; it will do no harm to introduce them again.
Birdy Edwards; Sholto Jiminez; Jefferson Burns; Murdo Olsen."

"Very pleased, Tenant, gentlemen. I met all you young men last
evening; I remember you," Altamont said. "Now, if you'll all crowd in
here, I'll explain what we're going to try to do."

He showed them the old picture. "You see where the shadow of a tall
building falls?" he asked. "We know the location and height of this
building. Dr. Loudons will hold this helicopter at exactly the
position of the top of the building, and aim through the sights of the
rifle, there. One of you will have this flag in his hand, and will
move it back and forth; Dr. Loudons will tell us when the flag is in
the sight of the rifle."

"He'll need a good pair of lungs to do that," Verner Hughes commented.

"We'll use radio. A portable set on the ground, and the helicopter's
radio set." He was met, to his surprise, with looks of incomprehension.
He had not supposed that these people would have lost all memory of
radio communication.

"Why, that's wonderful!" the Reader exclaimed, when he explained. "You
can talk directly; how much better than just sending a telegram!"

"But, finding the crypt by the shadow; that's exactly like the--"
Murray Hughes began, then stopped short. Immediately, he began talking
loudly about the rifle that was to be used as a surveying transit,
comparing it with the ones in the big first-floor room at the
Aitch-Cue House.

* * * * *

Locating the point on which the shadow of the old Cathedral of
Learning had fallen proved easier than either Altamont or Loudons had
expected. The towering building was now a tumbled mass of slagged
rubble, but it was quite possible to determine its original center,
and with the old data from the excellent reference library at Fort
Ridgeway, its height above sea level was known. After a little
jockeying, the helicopter came to a hovering stop, and the slanting
barrel of the rifle in the vise pointed downward along the line of the
shadow that had been cast on that afternoon in June, 1993, the cross
hairs of the scope-sight centered almost exactly on the spot Altamont
had estimated on the map. While he peered through the sight, Loudons
brought the helicopter slanting down to land on the sheet of fused
glass that had once been a grassy campus.

"Well, this is probably i