ric altimeter, not the radar--and hold position."

Loudons leaned forward from the desk to the contraption Altamont
had rigged up in the nose of the helicopter; one of the
telescope-sighted hunting rifles clamped in a vise, with a
compass and a spirit-level under it.

"Rifle's pointing downward at the correct angle now?" he asked.
"Good. Then all I have to do is to hold the helicopter steady,
keep it at the right altitude, level and pointed in the right
direction, and watch through the sight while you move the flag
around, and direct you by radio."

"Simple, if I had been born quintuplets!"

"Mr. Altamont! Doctor Loudons!" a voice outside the helicopter
called. "Are you ready for us now?"

Altamont went to the open door and looked out. The old Toon
Leader, the Reader, Toon Sarge Hughes, his son and four young men
in buckskins with slung rifles were standing outside.

"I have decided," the Tenant said, "that Mr. Rawson and Sarge
Hughes and I would be of more help than an equal number of young
men. We may not be as active, but we do know the old ruins
better, especially the paths and hiding places of the Scowrers.
These four young men you probably met last evening, but it will
do no harm to introduce them again.

"Birdy Edwards; Sholto Jiminez; Jefferson Burns; Murdo Olsen."

"Very pleased, Tenant, gentlemen. I met all of you young men last
evening and I remember you," Altamont said. "Now, if you'll 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 height and location
of this building. Doctor 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. Doctor Loudons will
tell us when the flag is in sight of the rifle."

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

"We'll use the radio. A portable set on the ground, and the
helicopter's radio set," Altamont said.

To his surprise, he was met 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 the
explanation was concluded. "You can talk directly. How much
better than just sending a telegram!"

"But, finding the crypt by the shadow, that's exact