early where he was. He knew within a close margin just where the
terror beam stretched. He'd smashed his watch, which during sunshine
substituted admirably for a compass, but he could maintain a
reasonably straight line toward that part of the Park's border the
terror beam would cross.

They moved doggedly over mountain-flanks and up valleys, and once they
followed a winding hollow for a long way because it led toward their
destination without demanding that they climb. It was in this area
that, pushing through brushwood beside a running stream, they came
abruptly upon a big brown bear. He was no more than a hundred feet
away. He stared at them inquisitively, raising his nose to sniff for
their scent.

Lockley bent and picked up a stone. He threw it. It clattered on
rocks on the ground. The bear made a whuffing sound and moved
aggrievedly away.

"I'd have been afraid to do that," said Jill.

"It was a he-bear," said Lockley. "I wouldn't have tried it on a
she-bear with cubs."

They went on and on. At mid-morning Lockley found some mushrooms. They
were insipid and only acute hunger would make them edible raw, but he
filled his pockets. A little later there were berries, and as they
gathered and ate them he lectured learnedly on edible wild plants to
be found in the wilderness. Jill listened with apparent interest. When
they left the berry patch they swung to the left to avoid a steep
climb directly in their way. And suddenly Lockley stopped short. At
the same instant Jill caught at his arm. She'd turned white.

They turned and ran.

A hundred yards back, Lockley slackened his speed. They stopped. After
a moment he managed to grin mirthlessly.

"A conditioned reflex," he said wryly. "We smell something and we run.
But I think it's the old familiar terror beam that crosses highways to
stop men from using them. If it were a portable beam projector with
somebody aiming it, we wouldn't be talking about it."

Jill panted, partly with relief.

"I've thought of something I want to try," said Lockley. "I should
have tried it yesterday when I first smashed my watch."

He retraced his steps to the spot where they'd caught the first whiff
of that disgusting reptilian-jungle-decay odor which had bombarded
their nostrils. Jill called anxiously, "Be careful!"

He nodded. He got the coiled bronze watchspring out of his pocket. He
went very cautiously to the spot where the smell became noticeable.
Standing well back from