crystal bubbles of the ice-ants marked the glacial surface of the hills, but these creatures never emerged, laboring incessantly beneath their little domes that grew like mushrooms as they melted within and received fresh deposits of ice crystals without. A lonely world, a wild, bizarre, forbidding, and unearthly little planet.
It never actually snowed on Titan. The chill air could absorb too little water vapor for condensation as snow, but there was a substitute. During the days, when the temperature often passed the melting point, shallow pools formed on the frozen oceans, augmented sometimes by mighty eruptions of frigid brine from below. The ferocious winds swept these pools into a spindrift that froze and went rushing as clouds of icy needles around the planet.
Often during the darkness Diane had watched from the window as one of these clouds loomed glittering in the cold-green Saturn-light, sweeping by with a scream and slithering of ice crystals on the walls, and seeming to her mind like a tall, sheeted ghost. At suds times, despite the atom-generated warmth of the tiny dwelling, she was apt to shiver and draw her garment closer about her, though she was careful that Tim never observed it.
So time passed in the trading shack, slowly and dismally. The weather, of course, was uniformly, unvaryingly terrible, such weather as only Titan, nearly nine hundred million miles from the moderating Sun, can present. The little world, with its orbital period of fifteen days and twenty-three hours, has no perceptible seasons; only the recurrent shifting of the winds from east to west marks its swing about gigantic Saturn.
The season is always winter—fierce, bitter, unimaginable winter, to which the earthly storms of desolate Antarctica are as April on the Riviera. And little by little, Saturn edged closer to the Sun, until one day the western streak of its rings knifed a dark gash across the reddish disk. The eclipse was at hand.
That night saw the catastrophe. Tim was dozing on the bunk; Diane was dreaming idly of green fields and warm sunlight. Outside roared a gale more than usually vociferous, and a steady parade of ice ghosts streamed past the windows. Low and ominous came the roar of shifting glacial mountains; Saturn and the Sun, now nearly in a direct line, heaved at the planet with a redoubled tidal pull. And then suddenly came the clang of warning; a bell rang ominously.
Diane knew what it meant. Months before, Tim had driven a row of posts into the ice, extending toward the cliff that sheltered the whiplash grove. He had foreseen the danger; he had rigged up an alarm. The bell meant that the cliff had shifted, had rolled upon the first of the stakes. Danger!
Tim was springing frantically from the bunk. "Dress for outside!" he snapped. "Quickly!"
He seized her lunacy sponge-rubber parka and tossed it to her. He dragged on his own, cranked the door open to the pandemonium without, and a fierce and bitter blast swept in, upsetting a chair, spinning loose articles around the room.
"Close the emergency pack!" he yelled above the tumult. "I'll take a look."
Diane suppressed her upsurging fear as he vanished. She strapped the pack tightly, then poured the precious eighteen flame-orchids into a little leather pouch, and suspended this about her throat. She forced calmness upon herself; perhaps the ice cliff had stopped, or perhaps only the wind itself had snapped the warning post. She righted the chair and sat with her visor open despite the knife-sharp blasts from the door.
Tim was coming. She saw his gloved hand as he seized the doorframe, then his fur-masked face, eyes grins behind the non-frosting goggles.
"Outside!" he yelled, seizing the pack.
She ruse and scrambled after him into the howling inferno just as the second bell clanged.
Barely in time! As the tornado sent her sprawling and clutching, she had a sharply etched glimpse of a mighty pinnacle of glittering ice looming high above the shack; there was a rumble .d a roar deeper than the winds, and the shack was gone. One iron wall, caught by the gale, swept like a giant bat above her, and she heard it go clanging and clattering along the slope to the east.
Dazed and horribly frightened, she clawed her way after Tim into the shelter of a ridge, watching him while he wrestled the pack that struggled in the blast like something living. She was calm when at last he got it strapped to his shoulders.
"This is the end, isn't it, Tim?" she said, putting her visor close against his helmet, "Because I'm glad I came with you, then. I'm glad it's both of us together."
Tim groaned despairingly, and the blast tore the sound away. He turned suddenly, slipping his arms around her figure. "I'm sorry, Di," he said huskily.
He wanted to kiss her—an impossibility, of course, in a Titanian night. It would have been a kiss of death; they would have died with lips frozen together. He put away the thought that maybe that might he a pleasanter way, since death was inevitable now, anyway. Better, he decided, to die fighting. He pulled her down into the lee of the ridge and sat thinking.
They couldn't stay here; that was obvious. The rocket wasn't due for three months, and long before then they'd be frozen corpses, rolling away before the hurricane or buried in some crevasse. They couldn't build a habitable shelter without tools, and if they could, their atomic stove was somewhere under the shifting cliff. They couldn't attempt the journey to Nivia, a hundred miles away across the Mountains of the Damned—or could they? That was the only possible alternative.
"Di," Tim said tensely, "we're going to Nivia. Don't be startled. Listen. The wind's just shifted. It's behind us; we have almost eight Earth days before it changes. If we can make it—twelve, thirteen miles a day— if we can make it, we'll be safe. If we don't make it before the wind shifts—" He paused. "Well, it's no worse than dying here."
Diane was silent. Tim frowned thoughtfully behind his goggles. It was a possibility. Pack, parka, and all, he weighed less than Earth weight; not as much less as one would think, of course. Titan, although no larger than Mercury, is a dense little world, and, besides, weight depends not only on a planet's density, but also on distance from its center. But the wind might not hinder them so much, since they were traveling with it, not against it. Its terrible thrust, fiercer than even an equal Earth wind because the air contained thirty per cent of the heavy gas xenon, would be dangerous enough, but—Anyway, they had no choice.
"Come on, Di," 'Tim said, rising. They had to keep moving now; they could rest later, after sunrise, when the danger of a frozen sleep was less.
Another terrible thought struck Tim—there would be only three more sunrises. Then for four Titanian days, the little satellite would be in the mighty shadow of Saturn, and during that long eclipse, heaven alone knew what terrific forces might attack the harassed pair crawling painfully toward Nivia, the City of Snow.
But that had to he faced, too. There was no alternative. Tim lifted Diane to her feet, and they crept cautiously out of the shelter of the ridge, bowing as the cruel wind caught them and bruised them, even through their thick suits, by flying ice fragments.
It was a dark night for Titan; Saturn was on the other side of the little world, along with the Sun it was soon to eclipse, but the stars shone brilliant and twinkling through the shallow, but very dense and refractive, atmosphere. The Earth, which had so often lent a green spark of cheer to the lonely couple, was not among them; from the position of Titan, it was always near the Sun and showed only just before sunrise or just after sunset. Its absence now seemed a desolate omen.
They 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