he red stratum would be ore. The other prospecting parties--none
of them found anything."

"We'll try again next spring," he said. "We'll find it somewhere, no
matter how long it takes."

"Our time may not be so long. The observations show the sun to be
farther south than ever."

"Then we'll make double use of the time we do have. We'll cut the
hunting parties to the limit and send out more prospecting parties.
We're going to have a ship to meet the Gerns again."

"Sometimes," George said, his black eyes studying him thoughtfully, "I
think that's all you live for, Bill: for the day when you can kill
Gerns."

George said it as a statement of a fact, without censure, but Humbolt
could not keep an edge of harshness out of his voice as he answered:

"For as long as I'm leader that's all we're all going to live for."

He followed the game south that fall, taking with him Bob Craig and
young Anders. Hundreds of miles south of the caves they came to the
lowlands; a land of much water and vegetation and vast herds of unicorns
and woods goats. It was an exceedingly dangerous country, due to the
concentration of unicorns and prowlers, and only the automatic crossbows
combined with never ceasing vigilance enabled them to survive.

There they saw the crawlers; hideous things that crawled on multiple
legs like three-ton centipedes, their mouths set with six mandibles and
dripping a stinking saliva. The bite of a crawler was poisonous,
instantly paralyzing even to a unicorn, though not instantly killing
them. The crawlers ate their victims at once, however, ripping the
helpless and still living flesh from its bones.

Although the unicorns feared the crawlers, the prowlers hated them with
a fanatical intensity and made use of their superior quickness to kill
every crawler they found; ripping at the crawler until the crawler, in
an insanity of rage, bit itself and died of its own poison.

They had taken one of the powerful longbows with them, in addition to
their crossbows, and they killed a crawler with it one day. As they did
so a band of twenty prowlers came suddenly upon them.

Twenty prowlers, with the advantage of surprise at short range, could
have slaughtered them. Instead, the prowlers continued on their way
without as much as a challenging snarl.

"Now why," Bob Craig wondered, "did they do that?"

"They saw we had just killed a crawler," Humbolt said. "The crawlers are
their enemies and I guess letting us live