,
standing silent and solemn in front of their caves as though they feared
they might never see their two fellows or the humans again.

The two mockers were pleasant company, riding on their shoulders and
chattering any nonsense that came to mind. And sometimes saying things
that were not at all nonsense, making Humbolt wonder if mockers could
partly read human minds and dimly understand the meaning of some of the
things they said.

They found a place where saltpeter was very thinly and erratically
distributed. They scraped off all the films of it that were visible and
procured a small amount. They completed their circuit and reached the
foot of the long, steep slope of the Craigs without finding anything
more.

It was an awesome climb that lay before them; up a grade so steep and
barred with so many low ledges that when their legs refused to carry
them farther they crawled. The heat was still very serious and there
would be no water until they came to the spring beyond the mountain's
summit. A burning wind, born on the blazing floor of the chasm, followed
them up the mountain all day. Their leather canteens were almost dry
when night came and they were no more than a third of the way to the
top.

The mockers had become silent as the elevation increased and when they
stopped for the night Humbolt saw that they would never live to cross
the mountain. They were breathing fast, their hearts racing, as they
tried to extract enough oxygen from the thin air. They drank a few drops
of water but they would not touch the corn he offered them.

The white mocker died at midmorning the next day as they stopped for a
rest. The yellow one crawled feebly to her side and died a few minutes
later.

"So that's that," Humbolt said, looking down at them. "The only things
on Ragnarok that ever trusted us and wanted to be our friends--and we
killed them."

They drank the last of their water and went on. They made dry camp that
night and dreams of cold streams of water tormented their exhausted
sleep. The next day was a hellish eternity in which they walked and fell
and crawled and walked and fell again.

Barber weakened steadily, his breathing growing to a rattling panting.
He spoke once that afternoon, to try to smile with dry, swollen lips and
say between his panting gasps, "It would be hell--to have to die--so
thirsty like this."

After that he fell with increasing frequency, each time slower and
weaker in getting up again. H