They stretched out flat, too exhausted for the moment even to bother with food.

A snore startled Rick and he sat up. It was Chahda, curled up in the long, white, padded coat he had acquired, and dead to the world.

"It's going to be no fun standing guard tonight," Rick said. "I have the third watch."

They had been rotating the guard, breaking the night into four parts. Tonight, Zircon would take the first hours, then Weiss. Weiss would awaken Rick who would stand watch until it was time to wake Scotty.

"You've got the best deal," Rick continued. "You can sleep in one stretch, and when you get up you won't have to go back to bed."

Scotty grinned. "Stop beefing. You'll get the last trick tomorrow night."

Rick rose wearily. "We'd better make chow. And wake up Chahda before he freezes to death. It sure is cold up here."

They found Zircon and Weiss together, staring at a cleft in the mountain that towered overhead.

"I told you we had forgotten something," Weiss was saying grumpily. "Binoculars ... one of the most obvious things."

"It was hard to think of everything," Zircon replied testily.

"What is it?" Rick asked.

Zircon pointed. "We saw a figure up there. It's gone now."

A s.h.i.+ver went through Rick. "The watchers! We haven't seen them for days."

"I'll wager they've seen us," Weiss muttered.

"But who are they?"

"I don't know," Zircon answered. "I've tried not to worry about it, because they've made no move to harm us. I think Sahmeed knows, but he isn't talking."

"It gives me the creeps," Scotty said.

"It is uncomfortable," Weiss agreed. "I hope they're nothing but curious Tibetans too shy to come into camp."

"That seems likely," Zircon nodded. "Yet, Chahda described Mongols. Ancient Mongols."

The sky was fast darkening now. Rick said with false optimism, "The bearers must know we're being watched and they don't seem afraid."

"That's why I'm not especially worried," Zircon said. "Well, let's make supper. I have the first watch, I believe."

Immediately after supper Rick crawled into his sleeping bag. But it seemed as though he had hardly closed his eyes before Weiss was shaking him.

Near by a mule snorted and a yak stirred restlessly. Rick crawled from his warm bed and pulled on his clothes, s.h.i.+vering in the cold. He took a blanket and wrapped it around his shoulders, then sat Indian fas.h.i.+on and tried to keep his head from nodding.

"Everything is quiet," the little professor said, as he handed Rick the rifle.

Silence in Tibet is like silence nowhere else, Rick thought. His imagination peopled the silence with hostile eyes that stared, watching his every move. He s.h.i.+vered again, not entirely from the cold. Who were the watchers?

A yak stood silhouetted against the sky, a low, strong bulk. Rick kept his eyes on the animal and tried to fight off sleep. The thin air made him drowsier than usual. He found his eyes drooping and he jerked upright, but sitting up straight was too tiring. He rested his head against a rock and felt the chill of it through the blanket.

Suddenly Rick was conscious of a funny buzzing sound in his head and his eyes felt parched. His neck had a crick in it.

Had he been asleep?

Impossible. The yak hadn't moved. The moon was still in the same place. He pulled back his sleeve to look at his watch. He had left it in his sleeping bag.

A stone rattled and he grabbed for the rifle.

"Fine guard you are," Scotty greeted him. "I could have stolen the blanket right off you without any trouble."

"Go back to bed," Rick said.

"Go to bed yourself," Scotty answered. "I've had sleep enough. Anything doing?"

"Not a thing." He handed Scotty the rifle and stood up. Around him were the sleeping forms of his friends. More distant were the huddled forms of the bearers, vague shapes in the darkness. The yak he had watched moaned softly.

"Tibet is yours," he said to Scotty and walked over to his sleeping bag. He inched into it, luxuriating in the warm fleece. The next thing he knew Scotty was shouting.

"Rick! Everybody, wake up!"

Scotty!

Rick jerked out of his sleeping bag, wide awake. Dawn was graying the rocks, and Scotty was running through the camp - through an empty camp!

"They're gone," he shouted.

Rick saw that the animals were gone. Only the lone yak remained, still staked in the spot where Rick had seen it during his watch - tied there, so they would be fooled into thinking the rest of the animals were there too. The shapes which he had taken to be the sleeping bearers were more rocks!

Sahmeed and the bearers had decamped with all the pack animals except the lone yak!

The professors were out of their sleeping bags now, staring incredulously about.

"But how ..." Weiss began.

"Look at me," Scotty moaned. "They walked off right under my nose, and I never heard or saw a thing!"

"Wait a minute," Rick said. "I thought I fell asleep last night, while I was on guard. Now I'm sure of it. They did all this while Z was on the job!"

"Don't be too sure," Zircon contradicted gruffly. "It might have happened to any of us. We'll probably never know. The point is, they've gone."

"The equipment," Weiss choked. "They've taken our equipment!"

"No, sir," Scotty said. "They piled it over there, behind those boulders."

Weiss ran to the equipment and checked it anxiously. "All here," he announced with relief.

Rick walked over to the remaining yak. It was staked next to a pile of ration cartons. "They took most of the rations," he said, "but they left us some. We won't starve for a while."

At the mention of the word, the others stopped short, full realization of their plight sinking in.

Suddenly Rick spun around, remembering. "Chahda!" he exclaimed.

The Hindu boy was gone, too.

"If they've hurt that boy ..." Zircon began.

"No signs of a struggle," Rick interrupted, "and we didn't hear anything. He must have gone voluntarily."

"If I ever get that big hulk of a Sahmeed in my sights," Scotty said grimly, "I'll blow him loose from his mustache!"

Zircon unfolded his maps and laid them on the ground. The others bent over them. "We'd better have a council of war," he said.

There were no villages within easy range, but beyond the Tengi-Bu Plateau there was a small settlement.

"How far?" Rick asked.

Zircon estimated. "Perhaps two weeks. Depends on the trails.'

Rick swallowed. "Two weeks there and two weeks back ..."

"That means the end of the experiment," Scotty said.

"No!" Julius Weiss exclaimed. "We can't let this stop us!"

"Let us be realistic," Zircon said. "Consider, Julius. Heaven knows I don't like the idea any more than you do. But our princ.i.p.al goal now must be to save our own lives."

"Why couldn't we set up the equipment right here and send a message?" Scotty asked.

"They won't be listening for us until the tenth," Rick reminded him.

"What's more," Zircon added, "we could never transmit from here." The sweep of his arm indicated the high mountains close overhead. "We are in a pocket.

Attenuation would absorb our signal, and the mountains would blanket what little did get out."

Scotty looked blank so Rick explained. "Attenuation means that the ground would absorb the signal. That's why we have to get to Tengi-Bu. It's high enough so there's no chance of interference."

"Or somewhere similar," Zircon added. "Any mountaintop would do, but most of these we couldn't climb ourselves, much less carry equipment."

Julius Weiss had been standing quietly, lost in thought. Now he spoke, his kindly face strained. "Hobart is right, boys. Our first thought must be of ourselves. The experiment must wait."

Rick knew what that announcement had cost the little scientist. Has Weiss been alone, he would have stayed with the equipment no matter what the cost. But he felt a responsibility to the others.

The boy tried to rea.s.sure him. "It isn't giving it up entirely, sir. We can get bearers and supplies and come back. Dad will keep trying for weeks if we don't answer on the tenth."

Zircon spoke decisively. "We will start for this village at once. Each of us will make a pack of blankets and rations. The rest of the rations will go on the yak."

"Will it be safe to leave the equipment?" Scotty asked.

"We must leave it," Weiss said sadly, "and pray that it will be unharmed when we return."

"If it is," Zircon added, "I will devote the rest of my life to finding Sahmeed. And Van Groot."

It was the calm tone of his voice that made Rick stare. It left no doubt that the big scientist would do just that.

As they lifted the improvised packs to their backs, Rick saw Weiss looking at the equipment, his eyes misty. Then the little scientist fell in step behind Zircon, who was leading the yak. For two years the scientists had dreamed of this project. Now July tenth was almost here and they wouldn't be set up to send the Spindrift message.

As they plodded along, Rick kept thinking of the Hindu boy. "They must have kidnapped Chahda," he said to Scotty.

"I don't think so," Scotty objected. "I think he went voluntarily."

"But why?"

"Maybe he saw what the end of this would be, and figured he would pretend to play along until the bearers reached Nepal. That way, he could organize a rescue party and come back for us."

"That must be it," Rick agreed. "I hope Sahmeed doesn't get wise."

"When he gets in a tight spot h.e.l.l probably look in his 'Worrold Alm-in-ack' and talk them out of it," Scotty said.

Rick's thoughts returned to their own problems. Zircon had said that the village on the map was at least two weeks away. He hoped grimly that the food would hold out. His head was down and he almost b.u.mped into Scotty ahead of him as the tiny procession came to a sudden halt. He looked up and stared straight into a wall of rock that blocked their path.

"Dead end," Zircon said hollowly.

It seemed that the fates were s.p.a.cing their misfortunes with diabolical timing. There was no way around the wall of rock.

"Are you sure we made the right turn back yonder?" Weiss asked.

Zircon consulted the map. "So far as I can see, we're on the right trail."

Rick bent back as far as he could and looked at the steep walls hemming them in. Suddenly he pointed. "There's a path leading up the side of that wall," he said.

The scientists examined the mark in the rock which Rick had optimistically called a "path." Zircon shook his head. "I, for one, could never climb that," he declared.

"And I wouldn't try," Weiss added.

"Maybe I could climb it and take a look around," Rick suggested. "I might see a way out."

Weiss looked again at the precipitous climb. "It's too dangerous, Rick."

"I'll be all right," Rick a.s.sured him. Before the scientists could stop him, he had slipped off his pack and trotted toward the base of the cliff. Grabbing on to a jutting rock, he hauled himself up. Hazardous as the ascent had seemed from the ground, it proved to be even more treacherous when Rick found himself climbing. He tested each foothold before resting his weight on the treacherous shale. There was almost no incline to the rock wall and one slip would be his last. He reached a shelf, turned and looked down. The view brought a sick feeling into the pit of his stomach, and he decided not to look down again until he had reached the top.

Inch by inch, he wormed his way up the face of the cliff. It took a full twenty minutes to complete the dangerous climb, but at last he hauled himself to the very top and stood on the small square of summit.

He leaned over and looked down, waving to the party below.

"Okay," he shouted and the words echoed back from the mountains.

"How does it look?" he heard Scotty call. That was good. They could talk to each other because of the acoustics of the rock walls. He saw instantly why they had come to a dead end in their supposedly correct route.