The sun was hot and bright the next morning as they made their slow way on again. The canyon straightened, the steep walls of it flattening out to make a pair of ragged shoulders with a saddle between them.

They climbed to the summit of the saddle and there, suddenly before them, was the other side of the world-and the Chasm.

Far below them was a plateau, stretching endlessly like the one they had left behind them. But the chasm dominated all else. It was a gigantic, sheer-walled valley, a hundred miles long by forty miles wide, sunk deep in the plateau with the tops of its mile-high walls level with the floor of the plateau. The mountain under them dropped swiftly away, sloping down and down to the level of the plateau and then on, down and down again, to the bottom of the chasm that was so deep its floor was half hidden by the morning shadows.

"My G.o.d!" Barber said. "It must be over three miles under us to the bottom, on the vertical. Ten miles of thirty-three percent grade-if we go down we'll never get out again."

"You can turn back here if you want to," Humbolt said.

"Turn back?" Barber's red whiskers seemed to bristle. "Who in h.e.l.l said anything about turning back?"

"n.o.body," Humbolt said, smiling a little at Barber's quick flash of anger.

He studied the chasm, wishing that they could have some way of cutting the quartz crystals and making binoculars. It was a long way to look with the naked eye . . .

Here and there the chasm thrust out arms into the plateau. All the arms were short, however, and even at their heads the cliffs were vertical. The morning shadows prevented a clear view of much of the chasm and he could see no sign of the red-stained strata that they were searching for.

In the southwest corner of the chasm, far away and almost imperceptible, he saw a faint cloud rising up from the chasm's floor. It was impossible to tell what it was and it faded away as he watched.

Barber saw it, too, and said, "It looked like smoke. Do you suppose there could be people-or some kind of intelligent things-living down there?"

"It might have been the vapor from hot springs, condensed by the cool morning air,"

he said. "Whatever it was, we'll look into it when we get there."

The climb down the steep slope into the chasm was swifter than that up the canyon but no more pleasant. Carrying a heavy pack down such a grade exerted a torturous strain upon the backs of the legs.

The heat increased steadily as they descended. They reached the floor of the valley the next day and the noonday heat was so great that Humbolt wondered if they might not have trapped themselves into what the summer would soon transform into a monstrous oven where no life at all could exist. There could never be any choice, of course-the mountains were pa.s.sable only when the weather was hot.

The floor of the valley was silt, sand and gravel-they would find nothing there. They set out on a circuit of the chasm's walls, following along close to the base.

In many places the mile-high walls were without a single ledge to break their vertical faces. When they came to the first such place they saw that the ground near the base was riddled with queer little pits, like tiny craters of the moon. As they looked there was a crack like a cannon shot and the ground beside them erupted into an explosion of sand and gravel. When the dust had cleared away there was a new crater where none had been before.

Humbolt wiped the blood from his face where a flying fragment had cut it and said, "The heat of the sun loosens rocks under the rim. When one falls a mile in a one point five gravity, it's traveling like a meteor."

They went on, through the danger zone. As with the peril of the chasm's heat, there was no choice. Only by observing the material that littered the base of the cliffs could they know what minerals, if any, might be above them.

On the fifteenth day they saw the red-stained stratum. Humbolt quickened his pace, hurrying forward in advance of Barber. The stratum was too high up on the wall to be reached but it was not necessary to examine it in place-the base of the cliff was piled thick with fragments from it.

He felt the first touch of discouragement as he looked at them. They were a sandstone, light in weight. The iron present was only what the Dunbar Expedition had thought it to be; a mere discoloration.

They made their way slowly along the foot of the cliff, examining piece after piece in the hope of finding something more than iron stains. There was no variation, however, and a mile farther on they came to the end of the red stratum. Beyond that point the rocks were gray, without a vestige of iron.

"So that," Barber said, looking back the way they had come, "is what we were going to build a ship out of-iron stains!"

Humbolt did not answer. For him it was more than a disappointment. It was the death of a dream he had held since the year he was nine and had heard that the Dunbar Expedition had seen iron-stained rock in a deep chasm-the only iron-stained rock on the face of Ragnarok. Surely, he had thought, there would be enough iron there to build a small ship. For eleven years he had worked toward the day when he would find it. Now, he had found it-and it was nothing. The ship was as far away as ever . . .

But discouragement was as useless as iron-stained sandstone. He shook it off and turned to Barber.

"Let's go," he said. "Maybe we'll find something by the time we circle the chasm."

For seven days they risked the danger of death from downward plunging rocks and found nothing. On the eighth day they found the treasure that was not treasure.

They stopped for the evening just within the mouth of one of the chasm's tributaries.

Humbolt went out to get a drink where a trickle of water ran through the sand and as he knelt down he saw the flash of something red under him, almost buried in the sand.

He lifted it out. It was a stone half the size of his hand; darkly translucent and glowing in the light of the setting sun like blood.

It was a ruby.

He looked, and saw another gleam a little farther up the stream. It was another ruby, almost as large as the first one. Near it was a flawless blue sapphire. Scattered here and there were smaller rubies and sapphires, down to the size of grains of sand. He went farther upstream and saw specimens of still another stone. They were colorless but burning with internal fires. He rubbed one of them hard across the ruby he still carried and there was a gritting sound as it cut a deep scratch in the ruby.

"I'll be d.a.m.ned," he said aloud.

There was only one stone hard enough to cut a ruby-the diamond.

It was almost dark when he returned to where Barber was resting beside their packs.

"What did you find to keep you out so late?" Barber asked curiously.

He dropped a double handful of rubies, sapphires and diamonds at Barber's feet.

"Take a look," he said. "On a civilized world what you see there would buy us a ship without our having to lift a finger. Here they're just pretty rocks.

"Except the diamonds," he added. "At least we now have something to cut those quartz crystals with."

They took only a few of the rubies and sapphires the next morning but they gathered more of the diamonds, looking in particular for the gray-black and ugly but very hard and tough carbonado variety. Then they resumed their circling of the chasm's walls.

The heat continued its steady increase as the days went by. Only at night was there any relief from it and the nights were growing swiftly shorter as the blue sun rose earlier each morning. When the yellow sun rose the chasm became a blazing furnace around the edge of which they crept like ants in some gigantic oven.

There was no life in any form to be seen; no animal or bush or blade of gra.s.s. There was only the barren floor of the chasm, made a harsh green shade by the two suns and writhing and undulating with heat waves like a nightmare sea, while above them the towering cliffs shimmered, too, and sometimes seemed to be leaning far out over their heads and already falling down upon them.

They found no more minerals of any kind and they came at last to the place where they had seen the smoke or vapor.

There the walls of the chasm drew back to form a little valley a mile long by half a mile wide. The walls did not drop vertically to the floor there but sloped out at the base into a fantastic formation of natural roofs and arches that reached almost to the center of the valley from each side. Green things grew in the shade under the arches and sparkling waterfalls cascaded down over many of them. A small creek carried the water out of the valley, going out into the chasm a little way before the hot sands absorbed it.

They stood and watched for some time, but there was no movement in the valley other than the waving of the green plants as a breeze stirred them. Once the breeze shifted to bring them the fresh, sweet scent of growing things and urge them to come closer.

"A place like that doesn't belong here," Barber said in a low voice. "But it's there. I wonder what else is there?"

"Shade and cool water," Humbolt said. "And maybe things that don't like strangers.

Let's go find out."

They watched warily as they walked, their crossbows in their hands. At the closer range they saw that the roofs and arches were the outer remains of a system of natural caves that went back into the valley's walls. The green vegetation grew wherever the roofs gave part-time shade, consisting mainly of a holly-leafed bush with purple flowers and a tall plant resembling corn.

Under some of the roofs the corn was mature, the orange-colored grains visible.

Under others it was no more than half grown. He saw the reason and said to Barber: "There are both warm and cold springs here. The plants watered by the warm springs would grow almost the year around; the ones watered by the cold springs only in the summer. And what we saw from the mountain top would have been vapor rising from the warm springs."

They pa.s.sed under arch after arch without seeing any life. When they came to the valley's upper end and still had seen nothing it seemed evident that there was little danger of an encounter with any intelligent-and-hostile creatures. Apparently nothing at all lived in the little valley.

Humbolt stopped under a broad arch where the breeze was made cool and moist by the spray of water it had come through. Barber went on, to look under the adjoining arch.

Caves led into the wall from both arches and as he stood there Humbolt saw something lying in the mouth of the nearest cave. It was a little mound of orange corn; lying in a neat pile as though whatever had left it there had intended to come back after it.

He looked toward the other arch but Barber was somewhere out of sight. He doubted that whatever had left the corn could be much of a menace-dangerous animals were more apt to eat flesh than corn-but he went to the cave with his crossbow ready.

He stopped at the mouth of the cave to let his eyes become accustomed to the darkness inside it. As he did so the things inside came out to meet him.

They emerged into full view; six little animals the size of squirrels, each of them a different color. They walked on short hind legs like miniature bears and the dark eyes in the bear-chipmunk faces were fixed on him with intense interest. They stopped five feet in front of him, there to stand in a neat row and continue the fascinated staring up at him.

The yellow one in the center scratched absently at its stomach with a furry paw and he lowered the bow, feeling a little foolish at having bothered to raise it against animals so small and harmless.

Then he half brought it up again as the yellow one opened its mouth and said in a tone that held distinct antic.i.p.ation: "I think we'll eat you for supper."

He darted glances to right and left but there was nothing near him except the six little animals. The yellow one, having spoken, was staring silently at him with some curiosity on its furry face. He wondered if some miasma or some scent from the vegetation in the valley had warped his mind into sudden insanity and asked: "You think you'll do what?"

It opened its mouth again, to stutter, "I-I-" Then, with a note of alarm, "Hey . . ."

It said no more and the next sound was that of Barber hurrying toward him and calling, "Hey-Bill-where are you?"

"Here," he answered, and he was already sure that he knew why the little animal had spoken to him.

Barber came up and saw the six chipmunk-bears. "Six of them!" he exclaimed.

"There's one in the next cave-the d.a.m.ned thing spoke to me!"

"I thought so," he replied. "You told it we'd have it for supper and then it said, 'You think you'll do what?' didn't it?"

Barber's face showed surprise. "How did you know that?"

"They're telepathic between one another," he said. "The yellow one there repeated what the one you spoke to heard you say and it repeated what the yellow one heard me say. It has to be telepathy between them."

"Telepathy-" Barber stared at the six little animals, who stared back with their fascinated curiosity undiminished. "But why should they want to repeat aloud what they receive telepathically?"

"I don't know. Maybe at some stage in their evolution only part of them were telepaths and the telepaths broadcasted danger warnings to the others that way. So far as that goes, why does a parrot repeat what it hears?"

There was a scurry of movement behind Barber and another of the little animals, a white one, hurried past them. It went to the yellow one and they stood close together as they stared up. Apparently they were mates . . .

"That's the other one-those are the two that mocked us," Barber said, and thereby gave them the name by which they would be known: mockers.

The mockers were fresh meat-but they accepted the humans with such friendliness and trust that Barber lost all his desire to have one for supper or for any other time. They had a limited supply of dried meat and there would be plenty of orange corn. They would not go hungry.

They discovered that the mockers had living quarters in both the cool caves and the ones warmed by the hot springs. There was evidence that they hibernated during the winters in the warm caves.

There were no minerals in the mockers' valley and they set out to continue their circuit of the chasm. They did not get far until the heat had become so great that the chasm's tributaries began going dry. They turned back then, to wait in the little valley until the fall rains came.

When the long summer was ended by the first rain they resumed their journey. They took a supply of the orange corn and two of the mockers; the yellow one and its mate.

The other mockers watched them leave, 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 sc.r.a.ped 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, following 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 h.e.l.lish 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 h.e.l.l-to have to die-so thirsty like this."

After that he fell with increasing frequency, each time slower and weaker in getting up again. Half a mile short of the summit he fell for the last time. He tried to get up, failed, and tried to crawl. He failed at that, too, and collapsed face down in the rocky soil.

Humbolt went to him and said between his own labored intakes of breath, "Wait, Dan-I'll go on-bring you back water."

Barber raised himself with a great effort and looked up. "No use," he said. "My heart-too much-"

He fell forward again and that time he was very still, his desperate panting no more.

It seemed to Humbolt that it was half a lifetime later that he finally reached the spring and the cold, clear water. He drank, the most ecstatic pleasure he had ever experienced in his life. Then the pleasure drained away as he seemed to see Dan Barber trying to smile and seemed to hear him say, "It would be h.e.l.l-to have to die-so thirsty like this."

He rested for two days before he was in condition to continue on his way. He reached the plateau and saw that the woods goats had been migrating south for some time. On the second morning he climbed up a gentle roll in the plain and met three unicorns face to face.

They charged at once, squealing with antic.i.p.ation. Had he been equipped with an ordinary bow he would have been killed within seconds. But the automatic crossbow poured a rain of arrows into the faces of the unicorns that caused them to swing aside in pain and enraged astonishment. The moment they had swung enough to expose the area just behind their heads the arrows became fatal. One unicorn escaped, three arrows bristling in its face. It watched him from a distance for a little while, squealing and shaking its head in baffled fury. Then it turned and disappeared over a swell in the plain, running like a deer.

He resumed his southward march, hurrying faster than before. The unicorn had headed north and that could be for but one purpose: to bring enough reinforcements to finish the job.