came to a long, smooth, wind-swept slope. They made the error of trying to cross it erect, trusting to their cleated shoes for secure footing. It was misjudgment; the wind thrust them suddenly into a run, pressed them faster and faster until it was impossible to stop, and they were staggering through the darkness toward unknown terrain ahead.
Tim flung himself recklessly against Diane; they fell in a heap and went sliding and rolling, to crash at last against a low wall of ice a hundred feet beyond.
They struggled up, and Diane moaned inaudibly from the pain of a bruised knee. They crept cautiously on; they ended a bottomless crevasse from the depths of which came strange roarings and shriekings; they slipped miserably past a glittering cliff that shook and shifted above them. And when at last the vast hulk of Saturn rose over the wild land before them, and the tiny reddish Sun followed like a ruby hung on a pendant, they were near exhaustion.
Tim supported Diane to a crevice facing the Sun. For many minutes they were silent, content to rest, and then he took a bar of chocolate from the pack and they ate, slipping the squares hastily through visors opened for each bite.
But under the combined radiance of Saturn and the Sun, the temperature rose rapidly more than a hundred degrees; when Tim glanced at his wrist thermometer it was already nearly thirty-eight, and pools of water were forming in the wind-sheltered spots. He scooped some up with a rubber cup, and they drank. Water at least was no problem.
Food might be, however, if they lived long enough to consume that in the pack. Humans couldn't eat Titanian life because of its arsenical metabolism; they had to exist on food laboriously transported from the Earth, or, as did the Nivian settlers, on Titanian creatures from whose substance the arsenic had first been chemically removed. The Nivians ate the ice-ants, the whiplash trees, and occasionally, it was sometimes whispered, the Titanian natives.
Diane had fallen asleep, lying huddled in a pool of icy water that flowed off into the open and then was whirled into sparkling spray by the wind. He shook her gently; they couldn't afford to lose time now, not with the shadow of the eclipse looming ominously so few hours away. But it tore his heart to see her eyes crinkle in a weary smile as she rose; he damned himself again for ever bringing her to this.
So they plodded on, haltered and trampled by the fierce and ruthless gale. He had no idea how far they had traveled during the night; from the crest of a high ridge he looked back, but the shifting hills of ice made localities hard to recognize, and he could not be sure that the grim escarpment far behind was actually the cliff that had crushed their shack.
He let Diane rest again from noon until sunset, nearly five hours. She regained much of the strength spent in the struggle of the night, but when the dropping sun set his wrist thermometer tumbling far toward the hundred-below-zero mark, it seemed to her as if she had not rested at all. Yet they survived another night of inferno, and the gray of dawn found them still staggering and stumbling before the incredible ferocity of that eternal wind.
During the morning a native appeared. They recognized him; in his clawed hands was the battered case of the eight-day clock. He sidled up to them, head toward the wind, and held out his short arms to display the mechanism; he whined plaintively and obviously thought himself cheated.
Tim felt an unreasoning hope at the sight of him, but it vanished immediately. The creature simply couldn't understand their predicament; Titan was the only world he knew, and he couldn't conceive of beings not adapted to its fierce environment. So the man stood silently as Diane wound the clock and responded dully to her smile as she returned it.
"This time, old fellow," she said to the native, "it's ticking away our lives. If we're not in Nivia by the time it stops again—" She patted the blunt head; the creature cooed and sidled away.
III
They rested and slept again during the afternoon, but it was a weary pair that faced the inferno of night. Diane was nearing exhaustion, not from lack of nourishment, but simply from the incessant battering she had received from the wind, and the terrific struggle that every step required. Tim was stronger, but his body ached, and the cold, striking somehow through the inch-thick parka had left him with a painfully frostbitten shoulder.
By two hours after sunset, he perceived hopelessly that Diane was not going to survive the night. She was struggling bravely, but she was unequal to the effort. She was weakening; the pitiless wind kept lashing her to her knees, and each time she rose more slowly, leaned more heavily on Tim's supporting arm. All too quickly came the moment he had foreseen with despairing heart, when she did not rise at all.
He crouched beside her; tears misted his goggles as he distinguished her words above the screaming of the blast.
"You go on, Tim," she murmured. She gestured toward the bag on her throat. "Take the flame-orchids and leave me."
Tim made no answer, but cradled her tired body in his arms, shielding her as best he could from the furious winds. He thought desperately. To remain here was quick death; at least he might carry Diane to some more sheltered spot, where they could sink more slowly into the fatal sleep of cold. To leave her was unthinkable; she knew that, too, but it had been a brave offer to make.
She clung weakly to him as he lifted her; he staggered a dozen steps before the wind toppled him, and the last struggle brought him to the lee of a low hillock. He dropped behind it and gathered the girl into his arms to wait for the cold to do its work.
He stared hopelessly ahead. The wild splendor of a Titanian night was before him, with the icy stars glittering on cold and glassy peaks. Just beyond their hillock stretched the smooth surface of a wind-swept glacier, and here and there were the crystalline bubbles of the ice-ants.
The ice-ants! Lucky little creatures! He remembered Young's description of them in the book at the shack. Within those domes it was warm; the temperature was above forty. He stared at them, fragile and yet resisting that colossal wind. He knew why; it was their ovoid shape, the same principle that enables an egg to resist the greatest pressure on its two ends. No one can break an egg by squeezing it endways.
Suddenly he started. A hope! He murmured a word to Diane, lifted her, and staggered out on the mirror-surface of the ice. There! There was a dome large enough—fully six feet across. He circled to the lee side and kicked a hole in the glittering roundness.
Diane crawled weakly through. He followed, crouching beside her in the dusk. Would it work? He gave a long cry of relief as he perceived the scurrying three-inch figures of the ice-ants, saw them patching the dome with crystal fragments.
Steam misted his nonfrosting goggles. He drew Diane against him and then opened his visor. Warm air! It was like balm after the bitter air without; it was musty, perhaps—but warm! He opened Diane's; she was sleeping in exhaustion and never stirred as he uncovered her pale, drawn features.
His eyes grew accustomed to the gloomy starlight that filtered through the dome. He could see the ice-ants, little three-legged ruddy balls that run about with a galloping motion. They weren't ants at all, of course, nor even insects in the terrestrial sense; Young had named them ants because they lived in antlike colonies.
Tim saw the two holes that pierced the saucerlike floor; through one, he knew, warm air came up from the mysterious hive below, and the other drained away the melting water of the dome. That dome would grow until it burst, but the ants didn't care; they'd sense the bursting point and have a new dome already started above the holes.
For a time he watched them; they paid no attention at all to the intruders, whose rubber suits offered nothing edible. They were semicivilized little creatures; he observed them curiously as they scraped a gray mold from the ice, loaded it on tiny sledges that he recognized as leaves of the whiplash tree, and tugged the load to one of the holes, dumping it in, presumably, to a handling crew below. And after a while he fell asleep, and precious time trickled away.
Hours later something awakened him to daylight. He sat up; he had been lying with his head pillowed