Bruce touched helmets. "This is it, pal. Keep the line clear of the sand."

Sam grabbed his arm. "Wait a minute."

"What's the matter?"

"Bruce - if we don't make it, I just want to say that you're all right."

"Uh ... oh, forget it. We'll make it." He started up. A herringbone step suited the convex approach to the hole. As Bruce neared the opening he shifted to side - step to fit the narrow passage and the concave shape of the morning glory above. He inched up, transferring his weight smoothly and gradually, and not remaining in one spot too long. At last his head, then his whole body, were in sunshine; he was starting up the morning glory itself.

He stopped, uncertain what to do. There was a ridge above him, where the flakes had broken loose when he had shoveled away their support. The break was much too steep to climb, obviously unstable. He paused only a moment as he could feel his skis sinking in; he went forward in half side - step, intending to traverse past the unstable formation.

The tow line defeated him. When Bruce moved sideways, the line had to turn a corner at the neck of the hole. It brushed and then cut into the soft stuff. Bruce felt his skis slipping backwards; with cautious haste he started to climb, tried to ride the slipping mass and keep above it. He struggled as the flakes poured over his skis. Then he was fouled, he went down, it engulfed him.

Again he came to rest in soft, feathery, darkness. He lay quiet, nursing his defeat, before trying to get out. He hardly knew which way was up, much less which way was out. He was struggling experimentally when he felt a tug on his belt. Sam was trying to help him.

A few minutes later, with Sam's pull to guide him, Bruce was again on the floor of the ca\'e. The only light came from the torch in Sam's hand; it was enough to show that the pile choking the hole was bigger than ever.

Sam motioned him over. "Too bad, Bruce," was all he said.

Bruce controlled his choking voice to say, "I'll get busy as soon as I catch my breath."

"Where's your left ski?"

"Huh? Oh! Must have pulled off. It'll show up when I start digging."

"Hmmm .. . how much air have you?"

"Uh?" Bruce looked at his belt. "About a third of a bottle."

"I'm breathing my socks. I've got to change."

"Right away!" Bruce started to make the switch; Sam pulled him down again.

"You take the fresh bottle, and give me your bottle."

"But - "

"No 'buts' about it," Sam cut him off. "You have to do all the work; you've got to take the full tank."

Silently Bruce obeyed. His mind was busy with arithmetic. The answer always came out the same; he knew with certainty that there was not enough air left to permit him again to perform the Herculean task of moving that mountain of dust.

He began to believe that they would never get out. The knowledge wearied him; he wanted to lie down beside the still form of Abner Green and, like him, not struggle at the end.

However he could not. He knew that, for Sam's sake, he would have to shovel away at that endless sea of sand, until he dropped from lack of oxygen. Listlessly he took off his remaining ski and walked toward his task.

Sam jerked on the rope.

Bruce went back. "What's got into you, kid?" Sam demanded.

"Nothing. Why?"

"It's got you whipped."

"I didn't say so."

"But you think so. I could see it. Now you listen! You convinced me that you could get us out - and, by Jimmy! you're going to! You're just cocky enough to be the first guy to whip a morning glory and you can do it. Get your chin up!"

Bruce hesitated. "Look, Sam, I won't quit on you, but you might as well know the truth: there isn't air enough to do it again."

"Figured that out when I saw the stuff start to crumble.

"You knew? Then if you know any prayers, better say them."

Sam shook his arm. "It's not time to pray; it's time to get busy."

"Okay." Bruce started to straighten up.

"That's not what I meant."

"Huh?"

"There's no point in digging. Once was worth trying; twice is wasting oxygen."

"Well, what do you want me to do?"

"You didn't try all the ways out, did you?"

"No." Bruce thought about it. "I'll try again, Sam. But there isn't air enough to try them all."

"You can search longer than you can shovel. But don't search haphazardly; search back toward the hills. Anywhere else will be just another morning glory; we need to come out at the hills; away from the sand.

"Uh... look, Sam, where are the hills? Down here you can't tell north from next week."

"Over that way," Sam pointed.

"Huh? How do you know?"

"You showed me. When you broke through I could tell where the Sun was from the angle of the light."

"But the Sun is overhead."

"Was when we started. Now it's fifteen, twenty degrees to the west. Now listen: these caves must have been big blow holes once, gas pockets. You search off in that direction and find us a blow hole that's not choked with sand."

"I'll do my darndest!"

"How far away were the hills when we got caught?"

Bruce tried to remember. "Half a mile, maybe."

"Check. You won't find what we want tied to me with five or six hundred feet of line. Take that pad of paper in my pouch. Blaze your way - and be darn sure you blaze enough!"

''I will!''

"Attaboy! Good luck."

Bruce stood up.

It was the same tedious, depressing business as before. Bruce stretched the line, then set out at the end of it, dropping bits of paper and counting his steps. Several times he was sure that he was under the hills, only to come to an impasse. Twice he skirted the heaps that marked other morning glorys. Each time he retraced his steps he gathered up his blazes, both to save paper and to keep from confusing himself.

Once, he saw a glimmer of light and his heart pounded - but it filtered down from a hole too difficult even for himself and utterly impossible for Sam.

His air got low; he paid no attention, other than to adjust his mix to keep it barely in the white. He went on searching.

A passage led to the left, then down; he began to doubt the wisdom of going further and stopped to check the darkness. At first his eyes saw nothing, then it seemed as if there might be a suggestion of light ahead. Eye fatigue? Possibly. He went another hundred feet and tried again. It was light!

Minutes later he shoved his shoulders up through a twisted hole and gazed out over the burning plain.

"Hi!" Sam greeted him. "I thought you had fallen down a hole.

"Darn near did. Sam, I found it!"

"Knew you would. Let's get going."

"Right. I'll dig out my other ski."

"Nope."

"Why not?"

"Look at your air gauge. We aren't going anywhere on skis."

"Huh? Yeah, I guess not." They abandoned their loads, except for air and water bottles. The dark trek was made piggy - back, where the ceiling permitted. Some places Bruce half dragged his partner. Other places they threaded on hands and knees with Sam pulling his bad leg painfully behind him.

Bruce climbed out first, having slung Sam in a bowline before he did so. Sam gave little help in getting out; once they were above ground Bruce picked him up and set him against a rock. He then touched helmets. "There, fellow! We made it!"

Sam did not answer.

Bruce peered in; Sam's features were slack, eyes half closed. A check of his belt told why; the blood - oxygen indicator showed red.

Sam's intake valve was already wide open; Bruce moved fast, giving himself a quick shot of air, then transferring his bottle to Sam. He opened it wide.

He could see Sam's pointer crawl up even as his own dropped toward the red. Bruce had air in his suit for three or four minutes if he held still.

He did not hold still. He hooked his intake hose to the manifold of the single bottle now attached to Sam's suit and opened his valve. His own indicator stopped dropping toward the red. They were Siamese twins now, linked by one partly - exhausted bottle of utterly necessary gas. Bruce put an arm around Sam, settled Sam's head on his shoulder, helmet to helmet, and throttled down both valves until each was barely in the white. He gave Sam more margin than himself, then settled down to wait. The rock under them was in shadow, though the Sun still baked the plain. Bruce looked out, searching for anyone or anything, then extended his aerial. "M'aidez!" he called. "Help us! We're lost."