As Lennon's clasp relaxed, the girl's tightened. She drew him toward the pony.

"You've got to ride," she said. "You can't stand the pace. That poison is no joke. Don't want to hold me back, do you?"

The question overcame Lennon's reluctance. The girl had refused to leave him, and she was right about the poison. He could endure the severe pain of his wounded hand, but he was still weak and badly shaken from the effects of the venom. Unless he rode he would be a drag upon her.

"Very well," he agreed, and he permitted her to help him clamber up into the saddle.

No time was lost over lengthening the stirrup leathers. Carmena handed him his rifle and the half-emptied gallon canteen, caught up the small one and her own rifle, and started off in lead of the pony. Her easy swinging stride, though seemingly unhurried, covered the ground faster than the pony could walk. Every little while the animal had to break into a jog to catch up with her.

At the far end of the scattered mesquite growth Carmena edged off to the left, down a shallow wash that brought them around to the west side of a ridge. Under cover of the gaunt earth-rib of worn rock she headed north, straight for the distant towers of Triple Butte.

The deceptive green of occasional palo-verde bushes now gave place to the columns of the giant sahuaro. The fluted, leafless stems of these high-towering cactus candelabras bristled with fierce thorns, yet each was crowned with the glory of a gorgeous foot-wide blossom.

Over the loose hot sand, amidst this shadeless mockery of a forest, Carmena swung steadily along at her graceful stride. Her movements seemed as lacking in effort as the lope of a coyote or the bound of a cat. Lennon would not have realized how greatly she was exerting herself had he not seen how frequently she drank from her canteen.

No one of white blood, however thoroughly inured to thirst, can walk fast under the blistering sun, in the bone-dry air of the desert, without need of much water. Lennon, though riding, was no less parched than the girl. He was fresh from a moist climate, and the Gila monster poison had put him into a feverish condition. Hard as he tried, he could not resist drinking. His canteen was emptied even sooner than Carmena's.

This was little past mid-afternoon. They had left the sahuaros behind and were coming down among widely scattered salt bushes to the border of an utterly barren alkali flat. For the first time since the stop in the mesquite, Carmena halted her quick advance. But it was not to rest. The feverish crimson of Lennon's face sobered her reassuring smile. She peered searchingly back along the trail, glanced at the sun, and hastily transferred to their empty canteens all but a quart from the full canteen on the saddlehorn.

"We've got to make it last till sundown, Jack," she warned. "Then, if only we can hold our lead, we'll be able to keep going all night."

Lennon drew out two half dollars. "How about trying these in our mouths?"

"They'll help," she replied, and she took one. "Be ready to tie your neckerchief over your nose, soon as we strike the alkali."

The wisdom of this advice was evident when they started out across the snow-white flat. Every step stirred up clouds of alkali dust that hung about the fugitives like thick smoke. The impalpable powder penetrated their clothes, smarted in their eyes, and all but choked them, even behind the veiling neckerchiefs.

Before they had half crossed the fearful dust flat Carmena was walking as slowly as the pony. At the far side she sank down beside a thick-stemmed cactus. Lennon, half delirious from fever, sought to spring off, with the vague idea of forcing her to ride. He succeeded only in tumbling upon the sand. The startled pony shied clear. With a smothered cry, Carmena leaped up to grasp his bridle.

"Close call!" she gasped at Lennon. "If he'd made off—no show for us at all."

Lennon was too far gone for speech. His canteen was already half empty. Carmena gave him a sip from her own and dragged him around until his head lay in the small blot of shade made by a cactus stem. Half an hour passed before he was able to get back into the saddle. But the rest appeared to have fully restored the girl's strength. She set off at a pace that again forced the pony into an occasional jog.

After a time the sheltering ridge ran down into the sandy level of the desert. Yet Carmena continued to find a route protected by inequalities of the ground or by growths of cactus and thorn scrub from any eyes that might be peering across the Basin. As the sun sank nearer to the western rim of buttes and mesas she kept an ever closer watch to the rear. Her own and Lennon's canteens were again empty and her seemingly tireless stride was at last beginning to flag.

By the time the lower edge of the sun touched the rim of the Basin the fugitives had come opposite a long range of broken hills. Carmena dragged herself wearily up over an out-thrust spur ridge. Lennon was swaying in the saddle, and his tongue, like hers, had begun to swell. But the girl did not offer to open the canteen on the saddlehorn.

At the top of the ridge she hurried the pony down below the skyline and crept back to peer over a ledge. Far to the rear, across the shadow-streaked waste, her anxious eyes sighted a group of moving dots. She ran to seize the pony's bridle and urge him into a jog.

"Must hurry!" she rasped in a thirst-harshened voice. "They're trailing us—on the lope!"

The alarm shocked Lennon out of his semi-delirium. His relaxing grip on the rifle tightened. He straightened in the saddle. Carmena did not look back at him. She was turning into the mouth of a wash that appeared to head over toward the far side of the hills. Half a mile up the wash the gravelly bottom changed to loose stones. Carmena smashed the smaller canteen and tossed it off to one side.

Some distance farther along the footing became all rock. Carmena stopped on a flat ledge and flung the big canteen she was carrying as far as she could up the arroyo. She then changed from her boots to the long-legged moccasins that she had hidden in one of the saddlebags. No less hastily she cut strips from the Navaho saddleblanket to tie over the pony's lightly shod hoofs.

The sun had now been down for several minutes, and the clear desert twilight was beginning to fade. Carmena turned the pony and carefully led him at an easy angle up a flight of solid step ledges on the side of the arroyo. Half circling a hill, she descended another arroyo that ran northwest, back down into the level desert.

By the time the edge of the broken ground had been reached dusk was deepening into night. Carmena halted and eased Lennon down out of the saddle. Water, trickled a few drops at a time between his cracked lips, gradually soothed his swollen tongue and parched throat. His fever was already subsiding in the coolness of nightfall.

Carmena gave him almost half of the remaining quart of water. A half pint more she used to rinse her own mouth and moisten the nostrils of the pony. The few sips left were held in reserve.

Scant as was the water ration, it enabled both the girl and Lennon to suck at lumps of raw bacon. They lay silently mouthing and chewing the greasy fat, their rifles ready and their ears alert for the slightest thud of approaching hoofs. But no sound broke the deathlike stillness of the desert night.

"Looks like we fooled 'em," whispered Carmena. "They must have found the canteens—figured we'd gone desperate with thirst and headed on across for the nearest water hole. Can you mount again?"

Lennon dragged himself to his feet.

"You're wonderful!" he murmured. "If you'd leave me here—I'm only a drag. You could ride at a gallop——"

She grasped his arm and pushed him around beside the horse.

"Don't be looney. We can go all night without a drop. Count on me to out-travel the pony till sun-up. Get on. You don't suppose I'm going back on my pard, do you?"

There was no room for argument. Lennon's condition was still so serious that she had to help him into the saddle. With the pony in lead, she set out straight toward the North Star.

Before many miles Lennon caught himself lapsing into a doze. He had almost dropped his rifle. To make certain against its loss, he thrust it into his cartridge belt like a pistol. After this he drowsed off again into a half torpor of sleep and exhaustion. Some automatic functioning of his subconscious mind kept him balanced in the saddle.

When at last he roused from the stupor it was to a miserable realization of pain and weariness and cold. A bleak gray light was filtering over the eastern rim of mesas down into the blackness of the Basin. Dry as was this land of desolation, it was not so utterly arid as the sea-level deserts of the lower Colorado.

Lennon shivered and forced open his heavy eyelids. He first made out the bowed figure of Carmena plodding along, with one backward-dragged hand noosed in the reins of the weary pony. The gray light gradually brightened. He saw that the girl was swaying, almost staggering. He forced out a hoarse cry:

"Stop!"

The call broke the hypnotic spell of motion that alone had enabled the girl to keep placing one leaden foot before the other. She tottered and sank down and lay still. Lennon dropped out of the saddle to bend over her. Like the knees of the pony, the girl's moccasins were torn with the thorns of cacti and desert bushes, against which they had struck in the dark.

She had not fainted. Her dark eyes gazed up at Lennon, wide with an anguish of self-reproach.

"Used up—can't make it," she whispered. "No chance for both—after sun-up. Ride hard toward Triple Butte."

Lennon's reply was to open the canteen and hold it to her lips. Only a few drops were left when she managed to thrust it away. He put his uninjured arm about her slender waist and lifted her to her feet.

"Ride—your turn," he commanded. "I walk. Never say die!"

Her sunken eyes lighted with a faint glow. A last flicker of strength enabled her, with his help, to pull herself into the saddle. Lennon caught up her rifle and started off toward Triple Butte in desperate haste.

An hour after sunrise found him still staggering forward almost at a dog trot. The northern border mesas of the Basin were now only a short distance ahead. But already his swollen tongue was beginning to blacken in his mouth. When at last he came to the foot of the lower mesa he could barely totter.

Carmena rode up alongside. She huskily whispered for him to hand over her rifle and grasp the stirrup leather. He had not dragged along beside the pony more than a hundred paces when a jerk on the reins headed the weary beast around into the mouth of a broad caÑon. Carmena uttered a sharp cry and pointed ahead. Near the base of the canon wall a dark patch on the ledges was shimmering in the sunrays.

Hope flared high in the hearts of the perishing fugitives—only to flicker and die out again in utter despair. The black patch was water—a tiny spring that seeped from a horizontal crevice between the stratas of rock—but its trickle was spread out in a paper-thin sheet down the sloping lower ledges. At their foot it vanished in the dry sand of the caÑon bed.

They could cool their swollen tongues and so obtain temporary relief from their suffering. But they could not suck up enough water to quench their terrible thirst. Nor could they collect in the canteen even a gill of water to take with them.

Lennon, however, was an engineer. Even while hope fled from him, his eyes were peering around with the scrutiny of a trained observer and thinker.

His roving gaze fixed upon a bank a little way out from the caÑon mouth. He staggered down to it and came back with a handful of dry clay. This he spread out upon the least tilted of the wet ledges. By patting and scraping he soon had a little ball that kneaded like putty in his eager fingers.

Carmena already had perceived his purpose and was hurrying to fetch a heaping hatful of the dry clay. Before many minutes they had built a little concave dam, in which the down-seeping water slowly but steadily collected.

When at last they had quenched their thirst Lennon took his rifle and went to sit under a shady ledge where he could look out into the Basin. Carmena lingered at the spring to water the pony and fill the canteen. She then gave all the cornmeal to the beast and brought slices of raw bacon to share with Lennon.

He clasped the hand in which she held out his first slice.

"So we made it, after all. Good work?"

"Yes, we made it, Jack!" she exulted. "Close shave—but worth the risk. I know now for sure you're a man, a real man!"

Her glowing eyes brought a deeper red into Lennon's sunburnt face.

"I'm still pretty much of a tenderfoot," he protested. "And there's this game arm. I'd rather run than fight."

The girl smiled.

"That's all right till you get back the use of your hand. But it won't hurt to show those bronchos the range of your rifle. They're coming a bit too fast to suit us."

Lennon stared out across the open plain. Rather more than a mile away a dozen or more riders were loping along the trail of the fugitives.

The sights slid up on Lennon's rifle. He put the butt to his left shoulder and rested the barrel across a rock. The first bullet raised a puff of dust a little to the left of the Indians. The second must have shrieked close over their heads. They wheeled their ponies and scattered out in fanlike formation.

Lennon's fourth shot caught one of the ponies broadside. The beast tumbled over and lay motionless. Its rider dashed behind a cactus. The rest of the Apaches wrenched their ponies about and raced to get back beyond range. They had not bargained on a rifle that could shoot so far. A renegade prefers to kill without risk to himself.

"That's enough," chuckled Carmena. "There's no cover for 'em unless they crawl up afoot. Some will ride around and climb the mesa. Time we were moving. Come on. We'll beat 'em into the Hole."

Lennon elevated his rifle and sent a parting shot over the heads of the fleeing riders. When he came running back into the caÑon mouth Carmena had the canteen swung to the saddlehorn and was lacing on her boots, in place of the torn moccasins.

After a last deep drink from the pool and another sombreroful for the pony, the little dam was carefully scraped off the ledge and the clay covered with a loose boulder. The Apaches would be able to lap the wet stone but not to drink. They were not engineers or dam builders.