Mother of Invention
(1953)
Astounding Science Fiction, December 1953
Tom Godwin

	The Star Scout's normal-space speed was far below that of light when she dropped out of hyperspace beyond the rim of the Thousand Suns. Two last stars lay beneath her; a binary composed of a small yellow sun and a larger blue-white sun. Observations were taken and instruments noted the tiny, shining mote that swung four hundred million miles out from the blue-white sun. Other instruments determined the new destination and the Star Scout vanished again into hyperspace. 

	When she dropped once more into normal space the shining mote had become a planet that blazed like a great, radiant gem against the black void beyond. The planet grew as the hours went by, filling the viewscreen as Blake braked for the descent into its atmosphere. Land masses and small oceans were faintly discernible through the fiery, opalescent haze that blanketed the planet. The image swelled and enlarged, the surplus running off the four sides of the screen, until the western side of a continent and a small portion of ocean filled the screen. 

	The four men in the deceleration chairs behind Blake, and held as helplessly as he by the force, watched the image on the viewscreen and the multiple hands of the air analyzer. The hands began to move as the first thin sample of air was scooped into the analyzer, then settled into position a few minutes later. 

	"Breathable." The gray-haired Taylor spoke with difficulty against the deceleration. "Less carbon dioxide than New Earth," Wilfred commented. Young, short and stocky, he was far less affected by the deceleration than the elderly ex-dean. "I can't understand why the spectroscope showed such an incredibly high percentage of carbon. How could any planet's crust contain such an excess of carbon?"

	"The carbon must be in the crust, rather than in the atmosphere," Taylor said. "Either that or the old spectroscope is erroneous. We know the air analyzer is a new and reliable instrument, but these old Warden spectroscopes, like men, develop eccentricities with age. If we had a new—"

	"Hang on," Blake interrupted, his eyes on the instruments before him. "I'm going to have to brake a little harder." The increased deceleration settled them all deeper in their chairs and no one spoke while the section of continent on the viewscreen became a hazy desert or plain through which ran dim wrinkles. The surplus slid away and the wrinkle in the center of the screen became a range of mountains. Blake watched the translucent white dot in the center of the screen that represented their point of landing and saw it would be along the eastern side of the mountain range. It would do as well as any other unknown section of the unknown world and he let the ship hold its course. The green line of a tree-bordered creek appeared, hugging the mountain's foothills, with the white dot between the creek and the mountain. The area covered by the dot became a small delta of alluvium from one of the canyons with a few trees scattered across it. The delta swept up to meet them, slowing as it came, with the white dot in a flat clearing that seemed to be of some curiously glittering sand. The Star Scout halted ten feet above the ground with a staccato of blasts from the drive tubes that sent the bright sand swirling in heavy clouds, then it dropped, cushioned by the drive, to touch the ground with a slight lurch. The wide tail fins settled in the sand and Blake cut off the drive. "And here we are," he remarked.

* * *

	The others were already hurrying to read the data recorded on the instruments; Taylor and Wilfred, Lenson and Cooke. Blake watched them, interested by their reactions. None of them had ever been off New Earth before, let alone on a world hitherto unknown to exist, and they were as excited as children with a new toy. Taylor, steeped in the academic environment all his life, was the most enthusiastic of them all. He had once told Blake: "With all due respect to ivied walls of stone, they can become a prison. I want to see a few things before I grow any older; deep space and distant suns and strange worlds—" Lenson, a tall, lean man with the easy grace of a cat, stood a full head taller than the pink young Wilfred; a pleasant sort of a man with a slow smile and a tolerant understanding of the foibles of others. There was the indefinable mark of the intellectual upon all three of them and among them the paradox, Cooke, stood out like a black sheep among white. He was, Blake knew, fully as intelligent as any of the others; he, like the others, had been selected by Taylor because his intelligence and knowledge were considerably greater than the intelligence and knowledge of the average graduate. But he did not look the part. His dark, hard-jawed face was not that of an intellectual. Neither were his broken nose and glittering black eyes. Blake watched him, thinking: He doesn't belong with the others; he belongs on Old Earth three hundred years ago, on the deck of a pirate ship with a bloody cutlass in his hand. But, for all his appearance of being a man of sanguine physical violence, Cooke seemed to be content to do no more than laugh at what his black eyes found in others and in life, itself. "Earth-type in every important respect," Taylor was saying. "Gravity, temperature, air. No indications of any harmful bacteria—we've been incredibly fortunate."

	"We had about one chance out of several thousand of this being an Earth-type planet, didn't we, Red?" Lenson asked, looking over at Blake. Blake nodded his red head. "Quite a few thousand, since this isn't a class-G sun. As Taylor said, we were incredibly lucky to hit the jackpot the very first try."

	"Then let's get out and look our find over," Cooke said, shifting restlessly. "Let's get out and romp across the sand and breathe some air we haven't breathed a million times already." Taylor looked questioningly at Blake and Blake nodded. "I don't see any reason why we shouldn't," he said. He checked the readings on the control board instruments from long habit and saw the red line that indicated the drive room's temperature. It was climbing rapidly, and he turned a knob marked: DRIVE ROOM—OUTSIDE VENTILATION. This would open the ports in the drive room and start the blower to rushing its great volumes of cool outside air through the overheated room. "Drive room's mighty hot from the decelerating," he said as he followed the others to the elevator. "If we had had a little more money left over, we could have had full-size coolers installed."

	"We were lucky to scrape up enough money to buy what we have," Wilfred said, dropping the elevator to the cabin level. "Our worries are over, now," Cooke declared. "Anyone who owns an Earth-type world isn't just rich—he's lord of all he surveys."

* * *

They stopped at the cabin level only long enough to procure a sidearm each. "You can't tell what you may run into on an alien planet," Blake said as he stepped back into the elevator. "No signs of any intelligent, civilized life, but there might be animals. Sometimes animals don't wait for you to run into them—they take a deep breath and do their level best to run into you and tramp you into the ground." They dropped to the lower air lock and went through it. The boarding ramp was dropped to the ground and they descended into the cloud of dust that still swirled about the ship. "The blower is filling the drive room with this dusty air," Blake said, sneezing. "I didn't realize it was so thick. But the drive room door is shut and none of this dust can get into the rest of the ship." They walked out away from the ship and the dust and stood in the glittering sand, looking about them curiously. The mouth of the canyon was visible above them, with the iridescent haze hiding the higher peaks. The trees were almost like those of the desert regions of New Earth, scattered very thinly across the mountain's foot, and viciously thorned bushes grew among them. Some of them, Blake noticed, were in bloom with exotically beautiful blossoms, ranging from delicate pink to vivid scarlet. "Pretty," Cooke commented. "A little dangerous to try to pick one, I'd say; those thorns are Nature's ice picks." 

	"We ought to name it . . . this world," Taylor said. "What shall we call it?" 

	"Aurora," Lenson said instantly. "She was the goddess of the dawn in ancient mythology. She was beautiful and she wore a veil. This world is beautiful and it wears a veil—that shining haze."

	"A good name," Taylor agreed. He looked toward the creek a few hundred feet away, the creek itself hidden by the green trees that grew thickly along its banks. "Let's get a sample of the water for analysis." They walked toward the creek, each of them unconsciously glancing back at the towering bulk of the ship as they went their way. Men always did that, Blake had noticed, when they set down on an alien planet. They would go out from their ship with their eyes alertly watching for danger ahead, and they never failed to look back at the ship as though to reassure themselves that its ponderous mass was still there. It was a normal thing to do; when a man set down on an alien world he was on his own and his only link with other humans and other worlds was his ship. It had brought him there; it, alone, could take him back. A man walked out from his ship knowing that it would be waiting for him to return, like a great, patient dog; waiting and ready to hurl itself into space at his command. Sometimes an alien planet held death for the bipeds who ventured to explore it, such as the spider-monsters of Nelson 14, and the ship would be the sword of vengeance for those who lived to fight their way back to it. The ship would avenge the fallen with fury in the thunder of its voice and annihilation in its flaming breath, leaving only drifting ashes where once had been alien things that had made the mistake of killing a human. Without their ship, men on a hostile, alien world would be near-helpless; with their ship, they were invincible conquerors. "Flowers, even," Cooke exclaimed as they neared the trees by the creek. "Red, blue, yellow, purple; green trees and good air—what more could we offer colonists?"

* * *

	Blake had been examining the shining sand with increasing curiosity and he stopped to inspect a bright crystal half the size of his hand. It was not quartz. He scratched at it with his knife point but could not make any impression. The same would have been true of quartz, but the crystal did not have the appearance of quartz. It was alive with internal fires and the crystal system, such as he could tell from its rounded, worn form, was distinctly not that of quartz. A little way farther on he found one that glowed a deep ruby red. He paused to pick it up, then hurried on at an excited exclamation from Lenson, who had gone with the others to the edge of the creek. "Look at this!"

	"This" was a crystal at the very edge of the creek's roiling, opalescent waters, the same deep ruby red as the one he had in his hand but a foot in diameter. Near it were other, smaller, crystals of blue-white, yellow, red, blue, green, with the blue-white ones predominating. The sand, gravel and rocks of the creek bed seemed to be composed exclusively of the bright mineral. "Did you ever see so many quartz crystals in your life?" Lenson was asking the others. "Or so many different colors? Look at this one—it looks like a ruby." Blake failed to hear the reply of the others, a thought he had had upon first examining the bright sand suddenly losing the fantastic quality which had caused him to dismiss it. It all checked, the lack of any mineral other than the one in the creek bed, the "erroneous" spectroscope that had shown the world to possess an impossible percentage of carbon, the high index of refraction possessed by the mineral. 

	He could find out very quickly. 

	"Let me have your diamond ring," he said to Wilfred. 

	Wilfred pulled it off his finger and handed it to him with a look of questioning surprise. Blake scratched the diamond in the ring across the red crystal he still held in his hand. It left no impression and he repeated the performance on several other crystals scattered on the ground near him. On none of them could he produce the faintest scratch with the diamond in Wilfred's ring, no matter how heavily he bore down. 

	"The spectroscope was right," he said, wondering if the others would find it as hard to believe as he did. "I don't see how it could be, but it is." 

	"Is what?" Wilfred asked. 

	"Carbon—all these crystals are diamonds!" They stared at him, incredulous. "They couldn't be!" Wilfred objected. Lenson asked, "How can you tell for certain? Are you sure?"

	"The diamond in this ring won't scratch them," he replied. "The only mineral a diamond can't scratch is another diamond."

	"Then they really are diamonds?" Taylor said, dropping to his knees to pick up a deep, bright-blue one that lay beside the ruby-red stone that Lenson had found. "But the variations in color—are they all diamonds?"

	"All those that are any size," Blake told him. "The softer silica would soon be reduced to a powder by the grinding action of the diamonds in the creek bed. Anything of any appreciable size that shines is pretty certain to be a diamond."

	"Hmm-m-m!" Cooke grunted, and shook his head in amazement. "I'm delighted to hear it, but it's still hard to believe. Talk about luck—here we sink our last cent to make this one trip, with the odds all in favor of our finding nothing, and the first thing we do is hit a double jackpot; not only an Earth-type—almost—planet but also an unlimited fortune in diamonds. Such luck is incredible."

	"It is incredible," Blake agreed. "It just isn't the sort of thing that—"

* * *

	His voice was drowned by a thunderous bellow from the ship. He whirled toward it, as did the others, wild disbelief on the faces of all of them. The same thought flashed in their minds at the same instant; they were all five there—there was no one in the ship! The ship shot into view, leaping high enough in the air that they could see it above the trees that surrounded them. A gout of blue-white flame was lashing from a hole torn in its stern, then the flame vanished and the ship poised motionlessly for a moment; a great, metal monster halted in mid-flight and pinned against the background of hazy sky. Then the nose dropped, the tail went up, and it fell. It fell in a horizontal position, its impact hidden from them by the trees but the sound of it loud and terrible to hear; the muffled scream of rending metal shrill above the ground-jarring thud of the impact. Blake ran past the others, toward the ship. He was vaguely aware of someone yelling, "What—" then he broke through the concealing trees and stopped, appalled by the sight that met his eyes. Spaceships were made to withstand the pull of gravity when at rest on their tail fins; to withstand the thrust of the drive which, whether accelerating or decelerating, was only the equivalent of gravitic attraction from the stern. They were constructed to possess great longitudinal strength, with no great cross-sectional strength needed. They were not constructed to withstand a horizontal drop. 

	The Star Scout was broken in two. 

	Taylor stopped beside him, white and shaken. 

	"What . . . what was it?" someone asked. "What happened . . . how could it happen?" 

	"The converter blew up," Blake said, his lips feelings oddly stiff and numb. "It was my fault—I should have had brains enough to think about it before it was too late." 

	"What do you mean?" Cooke demanded. 

	"I left the blower going, driving cool air into the drive room. The air was loaded with the dust we stirred up when we landed, and that dust was mainly diamond dust." 

	"Oh!" Cooke's eyes were fixed on Blake. "So that was it. Diamond dust—carbon—catalyst!" 

	"But how?" Taylor asked. "How could the diamond dust have gotten into the converter?" 

	"I don't know." Blake shook his head. "Maybe the inspection crew forgot to put the cover back on the fuel inlet—maybe the clamps broke while we were en route. Anyway, it happened—somehow enough of the dust got into the fuel inlet to put the amount of catalyst past a critical percentage and the converter exploded. I shouldn't have started the blower until I first went in and made a check of the fuel inlet." 

	"Why?" Cooke asked. "Did you ever hear of anything like this ever happening before?" 

	"No." 

	"Then why should you have checked? You had no reason to think the fuel inlet might be open, and neither did you discover this was diamond dust until about a minute before the explosion. You couldn't have done anything about it in only one minute." 

	"I suppose not," Blake agreed, "but I can't help feeling I should have been more careful. But that's all water under the bridge; here we are among our diamonds with no way of getting home—not for a long time at best, I'm afraid. So let's see just how long that may be, just how great the damage to the ship is." 

	"From here," Cooke observed as they walked toward the ship, "the situation looks hopeless. Our ship looks exactly like an overripe watermelon that's had a bad fall. It's not only broken in two, with a few girders holding the broken halves together, it's also sort of flattened now, rather than round like it once was." 

	"And gaping open at every seam," Wilfred added.

* * *

	They passed the stern of the ship, where the rim of the ragged hole still glowed redly with half-molten metal, and Blake motioned toward the deep furrow blasted in the ground where the ship had stood. "The blast was directional," he said. "If it hadn't been, it would have destroyed the lower half of the ship."

	"It didn't make such a big hole in the stern," Cooke remarked with a return of his characteristic optimism. We could patch it."

	"Of course," he added bleakly, "we'd only have half a ship to drive, and no converter to power our drive—if we have a drive left." They entered the ship by the gap where it had broken apart, climbing through the bent and broken steel. The elevator shaft, now a horizontal passageway, was accessible by climbing up the ragged, torn sheet metal and girders. Blake made a suggestion to the older Taylor before they climbed up into the elevator shaft. "I'd like to look at the drive room and the repair shop. So, suppose Cooke and I do that while you and the others see what the damage is in the forward half of the ship?"

	"Anything you say, Red," Taylor answered. "I have an idea we'll find nothing but wreckage either way." 

	"First, I'll get some lights for you," Blake said. 

	He climbed up into the elevator shaft and made his way to the supply level of the ship. The door to the room he entered opened with considerable difficulty and the scene inside, as revealed by his pocket lighter, was utter confusion and chaos. He found the locker that held the emergency lights under a mass of miscellaneous supplies, equipment and broken containers and took five lights from it. 

	He went back to the gap in the ship and tossed three of the lights to the others. They began to climb up into their own section of the ship and Cooke scrambled up to where he stood. 

	"How did it look where you were?" Cooke asked. 

	"Just a little untidy," he answered, leading the way to the drive room. 

	They forced the now-horizontal drive room door open and a gush of warm air struck them. The drive room was fairly well lighted by the hole the converter's explosion had produced and they appraised the damage, not caring to drop the ten feet to the new floor. 

	"That shapeless gob over there by the hole—that's all that remains of our converter," Blake said. "The explosion was directional, all right, and the converter was working at minimum output—if it had been up to as much as quarter output, it couldn't have remained directional and at a quarter output the entire ship would have vanished in a blaze of glory." 

	He flashed his light down into the shadowy corners of the room and found what he sought. "Look—see that square metal thing?" he asked. "That's the fuel inlet cover. Sure enough, it wasn't in place—they must have forgotten to tighten down the clamps." 

	"And we paid them to do that?" Cooke asked bitterly, flashing his own light over the cover.

* * *

	Blake moved his light slowly over the drive assembly. Originally equipped with the old Harding atomic drive, the transformation to the hyperspace drive had—for financial reasons—been confined to the installation of the space-shift units and the installation of the nuclear converter to supply the enormous energy required by the hyperspace units to wrench the ship from normal space into hyperspace. Although a modern drive would have been preferred, their limited capital had forced them to compromise by leaving the atomic rocket drive intact and modifying its fuel chambers to accept the tailor-made fuel prepared for it by the converter. 

	"How does it look?" Cooke asked. "I can't see where the blast did any damage to it. Am I right?" 

	"I think you are—the directional blast missed it and its construction was rugged enough that the fall didn't affect it. This is more than I had dared hope for—we can alter those fuel chambers back to the way they were and we have a rocket drive again. 

	"If," he added, "we can find uranium." 

	"And then what? Won't we be a little bit old and feeble by the time we get home through normal space, thirty thousand years from now?" 

	"Well, I don't know of any outpost of civilization we can reach in less than two hundred years," Blake said, "which would be too far to do us any good. However, to get anywhere in hyperspace, we still have to have a drive, you know. We have to have a drive to get off this planet so we can get in hyperspace in the first place." 

	"Once we fix up our drive and get away from here—how do we get into hyperspace with no converter to power the space-shift units?" Cooke asked. 

	"That is the question, and I don't know the answer. But I was taking first things first. If we can find uranium—and we surely can—we can soon solve every problem but that one." 

	He passed his light over the squat generator that had served to supply the ship with electrical power before the installation of the converter. It hung by two of its mounting bolts from the vertical floor, but it seemed undamaged. 

	"There's our power—if we had some way to store it," he said. "If we could devise a perfect condenser of unlimited capacity, we could accumulate enough power to give the space-shift units the wallop that would jump us into hyperspace. Anyway, whatever we do, we're going to need that generator. We're going to need electrical power for operating the lathe—if it isn't smashed beyond repair—welding, perhaps even for refining metals with some sort of an electric furnace." 

	"How do we power the generator?" Cooke asked. 

	"That can be done," Blake said. "Provided we have a lathe to build what we want." 

	He turned away from the drive room without further explanation and Cooke followed him to the repair shop. As with all other rooms in the ship's new position, the door was horizontal, but the repair shop was smaller than the drive room and it was no more than a six-foot drop to the new floor. Blake saw, with a sense of vast relief, that the lathe was still solidly bolted to the vertical floor. The other equipment was a jumbled mass on the floor and they poked into it curiously for a few minutes. 

	"Not much in the way of broken stuff here," Cooke said. "Steel tools seem to stand up pretty good when a ship does a belly-whopper. I hope the transmitter fared as well." 

	"That's something we're all hoping, but you're the first one to speak out loud about it," Blake said. "I don't see how it could have survived—a transmitter is big, heavy and fragile." 

	"Neither do I. I suppose that's why no one dared even say he hoped it wouldn't be smashed." 

	"Let's see about our truck," Blake said. "If the transmitter is smashed beyond repair, we'll have to try to find uranium and we'll stand little chance of prospecting these ranges on foot." 

	Again, luck had been with them. The little truck was unharmed but for a crumpled fender. Some of its bright red enamel had been knocked off by the fall of the diamond drill rods but the diamond drill, itself, seemed untouched. 

	"And that covers the important things in our end of the ship," Blake said. "Let's see what luck the others had."

* * *

	Wilfred was just descending from the broken elevator shaft, carrying a load of food and cooking utensils. "We'll camp out for a while, it looks like," he said. "With the new floors knee deep in wreckage and the doors six feet to ten feet up on the walls, living in the ship would be just a little inconvenient." 

	"We'll have to cut a passageway along the bottom side of the ship's hull," Blake said. "We can dodge the girders and just cut through the old flooring." 

	"How did it look up there?" Cooke asked. "What about the transmitter?" 

	"We won't send any SOS," Wilfred said flatly. "The transmitter tubes are smashed to fragments." 

	"I was afraid they would be," Blake said. "Do the others need help with their loads?" 

	"They could use some help, all right," Wilfred said, climbing down with his own. 

	They crossed the gap and met Lenson and Taylor in the elevator shaft, each with a burden of sleeping bags and various other things needed for a comfortable night outside. Blake and Cooke relieved them of part of their loads and the four of them carried their burdens to the clean, sandy spot near one of the trees where Wilfred had set up their "kitchen." 

	Blake dropped his load and spoke to Taylor. "So the transmitter is ruined?" he asked. 

	"The final power stage is," Taylor replied. "The drive stage took the fall pretty well and we could couple that in, except—" 

	"Except what?" 

	"In normal space that would give us a range of around a billion miles—no more than halfway to our sun's yellow companion. Useless." 

	"Oh—so we don't even get the chance to use our little driver stage in hyperspace?" 

	"The space-shift signal transformers are complete wreckage. Any signal we sent, even if we had our final power stage intact, would take three lifetimes to reach the nearest outpost through normal space. We could send a signal through hyperspace, with our drive stage, for sixty thousand billion miles—but the hyperspace transformers are broken and smashed and we could never, with our resources, replace them. So that brings up the question—what now?" 

	"Our space-shift units in the drive room seem to be undamaged and it wouldn't be difficult to change the rocket fuel chambers again so that we can lift the ship with an uranium fuel," Blake answered. "And we do have to lift the ship to make the jump into hyperspace under any circumstances. If uranium is to be found, we'll only have the one big problem to solve—and it's really big—how to produce enough power to activate the space-shift units. If necessity forced us to, I have an idea we might even make another converter. Of course, our success would be an uncertain thing and it would require years of work as well as luck, but it would be better than just giving up—at least, we would be trying." 

	He glanced toward the nearby canyon mouth. "Uranium is the vital essential, no matter what we do. I'm going to take a little walk while Wilfred fixes something to eat—I want to see what the formations look like, and if they offer any encouragement." 

	"And then we'll talk over our plans after we eat," Taylor said. "A man takes a more optimistic view of his circumstances when is stomach is full, anyway."

* * *

	Blake walked until he came to the first bank of rock and gravel, then examined what he found with considerable muttering. The formations represented by the rocks that had washed down out of the canyon were almost like those of any Earth-type planet, with one incredible exception; every rock, whether near-granite, near-rhyolite, near-andesite, whether high or low in silica content, contained almost the same high percentage of diamond crystal inclusions. In the coarse-grained rocks, such as the near-granites, the diamond crystals were as large as the end of his little finger, while the fine-grained near-rhyolites contained the diamonds as minute inclusions. But, whether the rock was fine- or coarse-grained, the diamond was present in all in approximately the same high percentage. 

	He had just come upon his first specimen of Aurora's animal life when he heard the distant call of Wilfred announcing dinner. He ignored the call for a moment, walking closer to the small, brown-furred animal. It was about the size of a squirrel, with a round, dark-eyed face and a fat little stomach that it scratched in an absent manner as it solemnly watched his approach. It let him reach within six inches of it before it scampered a few feet farther away from him, to stop and resume its solemn staring. 

	Wilfred called again and he turned back toward camp, the little animal staring after him as he went. Apparently they would have no ferocious carnivora to contend with on Aurora—the little animal had been without fear of him, or virtually so. It had not behaved in the manner of an animal accustomed to the law of "Run—or be eaten!" 

* * *

	Dishes were scrubbed with a generous amount of sand and a small amount of water after the meal was over, then Taylor began the discussion of their circumstances. "Our simplest solution would have been to send out an SOS," he said. "We could have contacted a ship easily enough on the emergency band—possibly one no more than a day or so from here." 

	"A day or so by hyperspace—two hundred years or more in normal space," Cooke commented. "A man doesn't really realize how great galactic distances are until he gets stuck thirty thousand light-years from home, does he?" 

	Lenson sighed and gave the broken ship a dark look. "I'm already beginning to acquire an unpleasant comprehension of the true magnitude of galactic distances." 

	"It seems to me that we have only two alternatives," Blake said. "We have to get either our ship or an SOS into hyperspace. We have the power to send the SOS through hyperspace, but the space-shift transformer that would send our signal into hyperspace is broken. The space-shift units that would send our ship into hyperspace are undamaged—but we haven't the power they would have to have. Which do we want to try to do—build a nuclear converter and take our ship back, or make a space-shift transformer for the transmission of an SOS?" 

	"We would not only have to make the transformer that would send our signal into hyperspace, we'd also have to replace the broken power stage of the transmitter," Taylor said. "The driver stage, even in hyperspace, would have a range so limited that it wouldn't reach the nearest outpost. Unless a ship happened to wander within its range, its signals would never be picked up. And Space being the size it is, that might not occur within our lifetimes." 

	"You think it would be useless to attempt to duplicate the space-shift signal transformer and the transmitter tubes?" Wilfred asked. 

	"I'm convinced that their duplication is beyond us," Taylor said. "They require special alloys as well as rare gases. They require delicate precision assembly; in fact, the machines that assemble them would require years of labor to build." 

	"We already have the means of putting our ship into hyperspace," Blake said. "All we need is the power. It seems to me we could more easily figure out a method of accumulating that power than we could build precision electronic equipment. After all, all we need is a tremendous store of energy to power our jump into hyperspace—a lot of energy for a short period. The drop back into normal space doesn't require but a fraction of that power." 

	"If there is no hope of sending an SOS, then we haven't any choice but to do that, have we?" Wilfred asked. 

	"I think we can safely say that the hope of sending an SOS is nil," Taylor said. 

	None of the others voiced any disagreement and Blake said: 

	"If we can find uranium, we won't have much trouble changing the fuel chambers to suit the fuel. We probably will have to spend more time making the ship—or the stern half of it—air-tight again than anything else. At any rate, the whole thing is hopeless unless we do rig up an atomic drive. We have to lift our ship into space to slip it into hyperspace and there's no use conjecturing on how we're going to take the second step until we know we can take the first step." 

	No one spoke for a few seconds, then Taylor said, "I suppose we agree on that, then. Now, the important thing is; can we find the uranium?" He looked at Blake. "How about it—what do you think of the possibilities?" 

	"I couldn't say," Blake answered. "I haven't seen any of this country, yet. I saw no evidence of metallic ores in the rocks washed down out of that canyon, but we could hardly expect to discover uranium that easily." 

	"What did you find?" Cooke asked. 

	"These rock formations are similar to Earth-type formations, and the silica content is about normal—if a person discounts the diamond present. The diamond is present in all formations, whether high or low in silica, usually as small to minute crystals. The larger crystals we saw must have come from pegmatitic formations." 

	"Which are—?" Cooke asked. 

	"Extremely coarse-grained bodies of rock. Minerals in pegmatitic form as unusually large crystals. On Charon we found a perfect quartz crystal that weighed a thousand pounds in a pegmatitic formation. Cummings—an old white-haired fellow who had been born on Old Earth—said that crystals much larger than that had been found on Old Earth in the past. 

	"There's something else about pegmatites," he added. "Pitchblende is sometimes found in pegmatitic formations. So, it may possibly be that the uranium ore we find—if we find any—will be in the same formation that these diamond boulders come from." 

	"Another thing—" Taylor said, thoughtfully. "We'll have to have cadmium. Cadmium and uranium—if we can find the two ores and refine them, we can alter the drive." 

	"Which will take how long—just as a wild guess?" Lenson asked. 

	Taylor smiled. "That's like asking how high is up. But, just as an optimistic guess, I'd say from one to two years." 

	Wilfred nodded his head in agreement. "I'd say that was about right—not less than one and not more than two years. We're lucky in that we have a lathe and other tools to work with, a truck to use for prospecting and all the mining equipment we need to mine the ore after we find it." 

	"The first thing will be to fix up a place to live," Taylor said, pulling up his pants leg to rub a skinned and bruised knee. "Climbing in and out of those rooms as we did this afternoon is hard work, and painful." 

	"Red suggested cutting a passageway along the bottom of the hull—using the bottom of the hull as the floor," Wilfred said. "That shouldn't take long. We can rearrange everything to accommodate the new floor and we'll certainly have to take the lathe down off the wall and set it up again on the floor." 

* * * 

	Their first Aurorian sunset stopped all talk of future operations a few minutes later. The sun was invisible behind some distant range, its last rays throwing lances of ruby, emerald and gold across the scintillating rainbow field that was the western sky. The lances shifted as they watched, widening and quivering with the splendor of their ever-changing colors until they rippled across the sky like the banners of some celestial fairyland. 

	Lenson was the first to speak, after the colors began to fade. "I never saw anything like that," he said, almost awe in his voice. 

	"Nor I," Cooke said, sprawling back against his sleeping bag. "That looks exactly the way my mother used to tell me heaven would look—before she decided I'd never go there, anyway." 

	"Probably caused by several different layers of air currents, traveling at different speeds and carrying varying amounts of dust and water vapor," Wilfred offered. 

	"Huh!" Cooke snorted. "Do you always have to be so pragmatic and practical?" 

	"Oh, it was impressive, I'll admit, but there was a simple, everyday reason for its beauty—the one I suggested, likely. Beautiful sunsets on Earth-type planets are due to water vapor and impurities in the atmosphere."

	"Then, so long as we're stuck here, let's be grateful that our atmosphere does contain these beautiful-sunset producing impurities," Lenson said.

* * *

	The afterglow faded from the sky and the Thousand Suns revealed themselves; a field of bright points of light shining through the haze with sufficient brilliance to throw dim shadows along the ground. 

	"We'll have to make observations," Taylor remarked. "I'll start making daily observations of our sun and its companion. We know the days here are about twenty-four hours long, but we don't know whether it's spring or summer—or possibly this world has no seasonal inclination of the poles." 

	"I think it's spring," Blake said. "The higher peaks we saw through the haze were covered with snow. Of course, that's not very conclusive evidence." 

	"Let's hope it's spring," Taylor said. "We know that our year is about six Earth-years in length and, with luck, we may be able to get away from here before winter comes." 

	There was a little more talk of their plans; then, one by one, they spread out their sleeping bags and crawled in. Blake, the last to retire, sat for a while watching the golden field the Thousand Suns made of the haze, reaching from the western horizon halfway to the zenith. To the east the sky was dead black, with no star to relieve it. There were none in that direction; not for a long, long way. Aurora had recently passed the farthest point from the Thousand Suns in her orbit; a straight line would pass from her to her sun, to close by the blue-white sun's yellow companion, then on into the Thousand Suns. 

	Blake remarked, just before he went to sleep, "You'll see what utter darkness is before morning—after the Thousand Suns go down and before the sun comes up."

* * *

	It required fifteen days to get the ship even partly in condition for living. There was the passage to be cut, doors to be fitted to keep out the fine dust stirred up by the afternoon winds, the ship's water tank to be equipped with sediment filters, the tables and chairs to be unbolted from their incongruous positions on what had become the walls, the truck to be lowered out of the ship—an endless number of things to be done. 

	Blake and Cooke left on the morning of the sixteenth day, leaving the other three to continue the work on and in the ship. They watched Blake and Cooke depart with a certain wistfulness and Cooke remarked, as they ground away through the sand, "I think all would have liked to go with us. They'll have nothing but hard work while we're out enjoying the fresh air and new scenery." 

	"You may change your mind about 'enjoying' it," Blake said. "Walking can be hard work when you do it all day." 

	"What's this truck for?" Cooke wanted to know. 

	"To haul our stuff. We won't use it any more than we have to—we can make new shoes by hand but we can't make a new truck." 

	"Do you think the diamond dust will be that bad?" 

	"I hope we find diamond dust and sand are the exceptions rather than the rule, but all evidence shows the diamond to be present everywhere. If so, we'll have to use the truck as little as possible—if we find the ores we want, then the truck will be indispensable for hauling them to the ship. Whatever we have to have for refining the ores will have to be at the ship—or we'll have to haul a good deal of material and equipment to the ore. Either way, we'll have to have this truck, so we'd better take care of it." 

	"I can see your point," Cooke agreed, "but I doubt that we'll wear it out very fast. After all, this thing was made to use in country where there was silica sand, and diamond is less than fifty per cent harder than silica." 

	"If you were correct in that surmise, I wouldn't be worried," Blake said. "What do you mean—'if'?" Cooke demanded. "Quartz has a hardness of seven and diamond has a hardness of ten. That's less than fifty per cent harder, isn't it?" Blake sighed. "The true and unpleasant facts are these: Diamond is said to have a hardness of ten because it's the only thing harder than corundum's nine. A mineralogist named Woodell, a long time ago and back on Old Earth, determined the true hardness of diamond in comparison with quartz's seven and corundum's nine. The actual hardness of diamond ranges from a fraction over thirty-six to a fraction over forty-two."

	"Oh." Cooke was thoughtfully silent for a while. "Then we can count on this diamond sand and dust being six times harder than the sand and dust this truck was made to resist."

	"Six times harder, and also tougher."

* * *

	They lurched across a small gulch and onto a silty flat, winding to avoid the thorn bushes that were scattered across it. The morning air was still and the dust they raised followed them in a dense cloud, coating their faces and clothing an iridescent gray, gritting harshly wherever two parts of metal moved together, such as the driving controls. They had traveled an hour, enclosed in the cloud of destructive dust, when Blake said, "I wonder—"

	"You wonder what?" Cooke asked, his black eyes made blacker by the gray dust that covered his face. "I wonder if this diamond dust hasn't got us behind an eight-ball—a big, shiny eight-ball named Aurora." They worked their way along the southern foot of the mountain, toward the high plateau to the east where the creek might have its headwaters. They prospected the canyons one by one, both by carrying back samples of the bedrock gravels to the truck, to pan for particles of the heavy uranium and cadmium ores they sought, and by use of the Geiger counters they each carried. Cooke ran the gauntlet from his first feeling of carefree adventure to a condition of sore, aching legs and blistered hands. Their picks and shovels wore away with amazing rapidity, even from digging in the comparatively loose gravels of the canyon beds, and they found nothing. They reached the eastern end of the range, a high, bleak plateau where the creek had its headwaters and where the nights were chilly with the breezes from the slowly melting snowbanks. There was nothing there but barren flow rocks and the inevitable diamond so they turned and worked their way back down the northern side of the range. Cooke's soft muscles hardened and his habitual optimism returned, undaunted by the lack of heavy-metal concentrates in the samples they panned or by the Geiger counters that remained silent but for the intermittent clicking of the natural background count. Twice they found veins of soft iron oxide and once they found a narrow vein of low-grade copper ore but the mountain seemed devoid of any uranium or of any lead-zinc ore that might contain the cadmium they needed. Blake cared for the little truck with painstaking attention, doing everything possible to keep the diamond dust out of its moving parts. But no way could be devised to keep the dust out of such moving parts as the brake drums, the ball and socket of the front-wheel drive, the control-lever linkage, the winch they were forced to use so many times, and many other moving parts. The air filter caused him more worry than anything else. He knew a certain amount of the fine dust was getting past the filter and into the motor, and there was nothing he could do about it. It was a good filter, made to protect an engine against silica dust; any silica dust fine enough to get past the filter would be too fine to cause any damage before it was reduced to an impalpable powder. But the diamond dust it admitted was six times harder than silica, as well as tougher—the diamond dust would refuse to be reduced to a harmless, impalpable powder. 

	They rounded the west end of the range early on the thirtieth day and saw the green line of the creek a mile away. The truck labored noisily as Blake turned it up a gentle grade toward the mouth of a narrow canyon and he shifted into a lower gear. 

	"It's a good thing we're only five miles from camp," Cooke said. "You're about three gears lower than you would be if this truck was in the same condition it was in when we left camp thirty days ago."

	"I'm afraid this will be its last trip—I've tried to baby it along and keep the dust out of it, but you just can't enclose a machine in a dust-proof wrapper."

* * *

	They left the truck on the smooth alluvial fan just outside the canyon's narrow portal and began the by now repetitious process of prospecting the canyon. It was late in the afternoon when they found their first cadmium; a thin gray seam of metallic sulfide in a rock washed down from higher on the canyon's wall. 

	"The gray sulfide is lead and zinc," Blake said. "Those little yellowish-orange spots in it are cadmium sulfide." 

	Cooke shook his head. "The percentage of cadmium is so slight—and the lead and zinc is only a thin seam." 

	"It might have wider portions where it's in place," Blake said, looking up the steeply sloping canyon's side. "It shouldn't be hard to find." 

	They located it in place an hour later, halfway up the canyon's side, but it was only a short, narrow seam. Blake tried unsuccessfully to dig into it with his prospector's pick, the point of which had long since been worn to a blunt stub. Cooke, pounding vainly at the tight-grained formation beside him, stopped to light a cigarette and wipe the sweat from his face. 

	"We have acids and glycerin," he said. "If we only had a few holes drilled in this rock, we could fill them with nitroglycerine." 

	"There's a chance in a thousand that it might get wider at a greater depth," Blake said, ceasing his own futile pounding. "But how do we drill holes in it?" 

	"The diamond drill—" Cooke began, then his voice trailed off. 

	"Exactly," Blake said, seeing what was suddenly in Cooke's mind. "How do we drill diamond-bearing rock with a diamond drill?" 

	"How did we intend to drill holes for mining when we started out thirty days ago? I won't argue about the diamond drill—I can't see how it could drill through diamond-bearing rock—but why didn't we think of all that before?" 

	"We didn't know for sure that all formations carried the same high percentage of diamond," Blake pointed out. "We hoped such wouldn't be the case, remember?" 

	"What a world to live on!" Cooke sighed. "Everything we try to do is foiled by diamonds. How can a superabundance of just one element manage to cause so much grief?" 

	"Well"—Blake shook his empty canteen and glanced to the west where the sun had disappeared behind the canyon wall—"we can't do any more here, now, so we might as well get on back to the truck and have something to eat before dark." 

	Cooke led the way to the bed of the canyon, his blithe spirits returned sufficiently for him to be whistling by the time they reached it. They were halfway to the canyon's portal when it became suddenly darker, as though a heavy cloud had covered the sun. It grew darker, although Blake's watch said the sun was not quite ready to set, and when they were almost to the portal's cliffs, where the canyon suddenly opened out upon the desert, he became aware of a low roar above the crunching of his footsteps in the diamond sand. It came from the desert beyond the portal; a sound like a distant waterfall. 

	Cooke, two hundred feet ahead of him, was still whistling cheerily and had obviously not heard it. Blake increased his pace and was almost up with him when Cooke stepped beyond the cliffs that still hid the desert from Blake. 

	Cooke stopped, then, a look of amazement on his face, staring in the direction of their truck and the desert beyond. Then he wheeled to shout back at Blake, "What is it?" 

	Blake was beside him a few seconds later and he saw the source of the sound he had heard. 

	It was a mile away; a great, high black wall rushing toward them, its towering crest lost in the atmospheric haze. It was racing toward them at perhaps fifty miles an hour, roaring with a deep, sustained roar and the sheer front of it seething and boiling. 

	"What—?" Cooke began, but Blake cut him off with a terse, "Come on!" He ran toward the truck, estimating the distance they must cover before the black wall reached them. The truck was not far—but the wall was traveling at least fifty miles an hour. 

	"Is it—" Cooke began again, then gave up as a gust of wind whipped sand in his mouth and devoted his full attention to keeping up with the fleet Blake. 

	They reached the truck with the black wall looming almost upon them and jumped inside, slamming the doors. "Sandstorm," Blake said, as Cooke started to ask again. A harder gust of wind lashed at the truck, stinging their faces with sand. "Close your window," Blake said as he cranked up his own. "Those baby zephyrs are the advance guard. I think we're in for a real one." 

* * * 

	The black wall struck a moment later with a thunderous roaring and screaming, smashing at the little truck with savage blows and enveloping them in darkness. Sand and gravel slashed against the windows with a sharp, dry hiss and, above the roar of the wind, Blake could hear a violent thumping as the wind found an empty and unfastened water can in the bed of the truck and slammed it back and forth. The pounding ceased abruptly and Blake had a mental vision of their water can going in kangaroo leaps across the mountainside. 

	" . . . long do you think?" Cooke shouted through the darkness. 

	"What?" Blake asked, shouting, himself, to be heard above the howl and roar of the storm. 

	"How long do you think this will last?" 

	"Don't know. Sometimes a sandstorm will last an hour, sometimes ten hours." 

	He felt inside the utility box under the dash and found a flashlight. Its beam had the appearance of a three-dimensional cone in the dust-filled air of the cab. 

	"How did that get in here so quick?" Cooke demanded. 

	"It comes in every little crack and crevice," Blake answered, flashing the light through the windshield. The light revealed the dust and sand flowing past them with incredible speed. There were bright gleams in the torrent of air and sand as larger pieces of diamond reflected the light for a microsecond and bits of dead vegetation were being carried along. 

	Blake shut off the light and made himself as comfortable as possible in his half of the small cab. "You might as well try to make your mind a contented blank for an indefinite number of hours," he advised. 

	Cooke followed his advice, grumbling at the lack of leg room. He was asleep within fifteen minutes; a fact Blake confirmed by a quick flash of the light. Blake sighed enviously and composed himself for the hours of futile thinking and worrying that would be his own lot until sleep came. There was, in the genial Cooke's philosophy, a blithe unconcern for "Unborn Tomorrow and Dead Yesterday." But, while he envied Cooke for his carefree attitude, he wondered if it would be of sufficient stability to survive the eventual recognition of a not-so-remote possibility—that all their efforts to leave their shining prison might prove to be futile. 

	The wind was shaking the truck and roaring with undiminished fury when he finally went to sleep, still worrying about the diamond dust that was being driven into every tiny crack about the truck wherever two parts of metal moved against each other. Silica, over a period of time, would ruin machinery. This was diamond, not silica; this had a hardness of forty-two, not seven— 

	He awoke at dawn, stiff and cramped, with Cooke's snoring loud in the silence that had replaced the storm. He jabbed an ungentle elbow into Cooke's ribs. "Wake up—the storm is over." 

	"Huh?" Cooke blinked and straightened with a moan. "My leg's been asleep so long it—Hey! What happened to our windows?" 

	"We now have frosted glass all around," Blake said, rolling down the opaque window on his own side. "Diamond sand is really tough on glass." 

	He stepped out of the truck into the calm morning air and looked at the damage. Cooke came around from the other side and stared open-mouthed at the bright, gleaming metal side of the truck where, before, there had been a thick coat of hard red enamel. 

	"It looks like we need a new paint job," he said at last. "And we'll have to knock a hole in the windshield to see how to drive to camp." 

	Blake lifted the motor cover and ran a finger through the blanket of diamond dust that covered every part of the motor. It was heaped on more thickly where there had been grease or oil to hold it. 

	"What do we do about that?" Cooke asked. 

	"Nothing. If we should try to wipe it off, it would cause it to work in deeper. We can only let it stay and hope the grease will keep most of it from getting any deeper into the moving parts." 

	"I wonder how they made out at camp?" Cooke asked as Blake lowered the motor cover. 

	"I was wondering the same thing. We'd better let the canyons to be prospected between here and camp wait for the time being. They're all near enough to camp that we can walk out to look at them, anyway." 

	They removed the opaque windshield and got under way, the steering wheel and gearshift lever grating harshly. They saw something shining metallically a half mile farther on and it proved to be their errant water can; lodged beneath a thorn bush, stripped of its enamel and polished to a high luster. 

* * * 

	Taylor and Lenson were waiting outside the ship when they drove up. The question and hope was plain to be seen on Lenson's face but there seemed an almost imperceptible anxiety tingeing the questioning look on Taylor's face. 

	Blake shut off the motor and climbed out. "Nothing," he said. "Not a sign of uranium." 

	Lenson's face reflected a natural disappointment but Taylor seemed to have something on his mind more serious than simple disappointment. "Then there's no hope of finding uranium in this range?" he asked. 

	"There was no indication whatever that there is any such thing anywhere along the range," Blake answered. He looked toward the ship. "Where's Wilfred?" 

	"He left early to spend the day prospecting. We have the ship pretty well fixed up inside and there hasn't been much to do the past few days. Now—how about other minerals? Did you find anything at all?" 

	"A thin seam of lead-zinc ore that carries a small percentage of cadmium. But I don't think the diamond drill could ever drill through the rock it's in." 

	Lenson grinned sourly. "I know it can't," he said. "We no longer have a diamond drill. While you were gone I got to looking around and found a formation that carried zircons. Since we'll need zirconium, we all three agreed it would be a good idea to set up the drill, put down some holes and blast out some zirconium-bearing ore. We set the drill up yesterday morning. By mid-afternoon we had worn out six of our eight diamond bits and were down four inches. I came back to the ship late in the afternoon to get some more oil for the drill's motor—we've been using it and it was getting worn—and the storm hit before I could get back to the drill. I had left the drill running; its progress was so slow that it didn't need any attention. I got lost in the darkness of the storm and finally had to hole up behind an outcropping until morning. Then I saw where I was and went on to the drill. I found the sand blowing into it while it was running had ruined it. Not only the motor, but the gears of the drill, itself." 

	"It was no loss, I'm afraid," Blake said. "All the formations Cooke and I saw carried the same high percentage of diamond." 

	"But suppose we should find some ore—how do we drill it without a drill?" Cooke asked. "That is, suppose we find some ore that isn't so hard and filled with diamonds as to make drilling impossible." 

	"In that case, we'd probably find we could fix up the old drill after all," Blake said. He turned to Lenson. "You said you had been using the drill's motor for something else—what was that?" 

	"Water pump," Lenson said. "It seemed like a foolish waste of effort and time to carry water to the ship's tanks in buckets so we took the little high-speed water pump that we had brought along for the very purpose of filling the ship's tanks, took the motor off the drill—we weren't using the drill then—stripped enough tubing out of the ship's air circulating system to reach to the creek and set up our pump." He grinned again. "It lasted long enough to fill one tank, then the bearings went out. We fixed it and a week later, when we used it again, the bearings went out again. Finally, the last time we used it, the impellers were half abraded away as well as the bearings and shafting cut out." 

	"And the motor was wearing out, too?" 

	Lenson nodded. "The bank was dry and sandy where we set the pump and breezes were always stirring up little clouds of dust. The motor was in pretty bad shape before it soaked through our thick skulls that the dust was pure diamond dust and not at all as harmless as it looked." 

	"So now you're back to carrying water in buckets?" Cooke observed. "And Red and I are going to be back to walking. This is a cruel world to anyone accustomed to mechanized assistance." 

	"About finding uranium—" Taylor said, the aura of worry still about him. "What would you suggest next?" 

	"We can hike across the desert to the nearest range and see what we can find," Blake said. "It will be slow, doing it all on foot, but we have a boundless supply of two things on this world—time and diamonds." 

	"No." Taylor shook his head. "Time is the very thing we don't have. I haven't said anything to Len or Wilfred about it yet. I wanted to wait until all five of us were here to talk over what we—" 

	"Hello." Wilfred's hail interrupted Taylor and he came hurrying toward them. "I saw your truck pull in so I turned around and came back. Any luck?" 

	"None," Blake said. "It just wasn't there to be found." 

	"What was this about not having time, and something you hadn't told us yet?" Lenson asked Taylor, his eyes on Taylor's face. 

	The others turned their attention to Taylor as he spoke. 

	"I've been making daily observations with the transit, as you know," he said. "I've observed the apparent motion of our sun, the yellow sun, and the Thousand Suns cluster. I found that this is spring—whether late or early I don't know—but that's of no importance. I thought, at first, the yellow sun was swinging in its orbit around our blue-white sun. You can see the yellow sun—like a very bright yellow star—in advance of our own sun each morning. According to my observations, the yellow sun is making an apparent advance of approximately one degree every five days in front of our own sun. This happens to be what its apparent advance should be as we swing out in our orbit, so I became suspicious and made other observations. I discovered we are approaching the Thousand Suns at a speed of one hundred miles a second." 

	"That's what you didn't tell us?" Lenson asked. "I don't understand—we'll either be long since gone from here, or long since dust, before our wandering binary reaches the nearest star of the Thousand Suns." 

	"I said the apparent advance of the yellow sun is accounted for by our own orbital movement," Taylor said. "There is no orbital movement of the yellow sun observable. This isn't a binary—the yellow sun is a member of the Thousand Suns." 

	"You mean—" Blake began. 

	"In approximately seven and a half months the two suns will collide." 

	"And our position in our orbit at that time?" 

	"We'll go into the yellow sun the radius of our orbit—four hundred million miles—in advance of the collision."

* * *

	Tall Lenson barely changed expression and the surprise on Wilfred's face hardened into quick stubbornness, as though he had already decided he would refuse to accept such a fate. Cooke leaned one hip on the fender of the truck, his black eyes flickering over the others as he analyzed their reactions. But for once, Blake felt, Cooke was finding nothing to amuse him. "You're sure your observations were accurate—that there's no hope we might have already swung past the yellow sun by then?" Blake asked. "I've made my observations as accurate as possible, and checked for errors. Our sun is moving toward the yellow sun at a hundred miles a second and a distance of slightly more than one and a half billion miles now separates them. Our observation of these suns couldn't indicate that they were not a binary during the brief period we dropped into normal space—especially with our limited means for taking observations from the ship. It was natural for us to assume that two suns so close together were a binary. Only very precise observations during the short time we observed them could have revealed the truth and we had neither the proper instruments for such observations nor any reason to think such observations were necessary."

	"It wouldn't have changed our circumstances," Blake pointed out. "With seven or eight months of grace, we would have landed to see what the planet had to offer in the way of mineral wealth, anyway."

	"That's true," Taylor said. "The result would have been the same. So here we are and we have, according to my most optimistic calculations, six months to fit our ship with a drive and get away from here as fast as we can." 

	"Six months?" Cooke demanded. "You said it would be seven and a half." 

	"We'll have to be a long way from here by then—Aurora carries an exceptionally high percentage of carbon and you know what happens when any nuclear conversion process absorbs an excess of carbon." 

	"Oh-oh—nova!" 

	"And they reach out a long, long way," Taylor said. 

	"The hyperspace units—the power for them—" Wilfred began. 

	"If we ever find a way to power them, it will have to be en route in space," Taylor said. "Or that's the safest course of action for us, I would say." 

	"I agree," Blake said. "If we can find ore pure enough, we might possibly be able to take off from here within six months. It would have to be exceptionally pure ore—it's improbable that we can find such ore but we don't know that it's impossible. The first thing we want to do is to start getting as far away from here as possible, and as fast as possible. Given pure enough ores, we can do that, I think." 

	"You said 'improbable but not impossible,' " Taylor said. "Just how improbable do you think it is?" 

	"If the other ranges are similar to this one, our chances are very poor. We can try; we can go out as two different parties to save time. Cooke has had experience in the hills, now, and could go with one of you to the range north of us while I went with the other to the range south of us. If there's nothing in the adjoining ranges, I would say there is no use looking farther." 

	"Why?" Lenson asked. 

	"Time. Time and distance. Any ore we found would have to be carried to the ship on our backs—the truck is worn out." 

	"Then let's start today," Cooke suggested. "Since our time is so short, we shouldn't waste an hour of it. Let's start right now." 

	Blake glanced at the early morning sun. "A good idea. We certainly won't have any days to waste. We'll take along about sixty days' supply of concentrated food tablets, plus spare shoe soles and, above all, canteens." 

	"The concentrated food tablets for two months—" Wilfred began doubtfully, but was interrupted. 

	"For roughage we can eat thorn berries," Blake told him. "Cooke and I tried them. They're tasteless, but they're completely harmless." He turned to Cooke. "You can take Wilfred across to the north range, and Lenson is better built for the hike across the desert to the south range than Wilfred is—it will be about three days on the water in our canteens to reach that south range." 

	"And if the south range has no creeks or springs in it—how will you come back across the desert without water?" Taylor asked. "We won't," Blake said simply. Cooke slid off the fender and looked at the truck, shaking his head. "If only we could have had this truck to use—"

* * *

	Blake and Lenson reached the south range on the third day of tramping across the glittering diamond sand of the desert, their throats burned and dry and their canteens empty. They found water; a seepage of sickening alkali water, but it was water. They found a creek of sweet water the next day as they started up the range's northern front, tumbling down out of the mountains and disappearing beneath the sand at the mountain's foot. It was a high, rugged range and they found other creeks and springs as they went. They reached its eastern end on the thirtieth day and turned down its southern face. They came to the last canyon on its southwest slope on the fiftieth day and knew they had failed. They had found an occasional vein of iron oxide and, once, a fairly soft vein of copper ore, but there had been no indications of uranium. 

	On the fifty-fourth day they reached the ship again, gaunt and ragged, with Blake's red whiskers flaming riotously and Lenson's brown beard giving him the look of a benign but destitute young religious father. 

	As though by prearranged plan, Cooke and Wilfred returned at the same time; Wilfred's pink face burned red by the sun, his blond whiskers sprouting raggedly, while Cooke wore a bushy black beard that, together with his glittering black eyes, gave him an even greater appearance of piratical fierceness. 

	Taylor was carrying two buckets of water to the ship when the four of them appeared. He set the buckets down and waited. 

	"No luck," Blake said as they drew near him. 

	"Same here," Cooke said. "That range we went to was as barren as this one." 

	"I've been continuing my observations," Taylor said. "Everything checks with my first ones, and now we're sixty days nearer the end. We'll have to start accomplishing something pretty quick." 

	"I know it," Cooke said, scratching at his black beard, the tattered sleeve of his shirt flapping in the wind. "But before we start any long talks on what we shall do next, let's have something to eat besides thorn berries and pills. And take a bath—I'm so covered with diamond dust that, in the nude, I'd glitter like a precious jewel." 

	Taylor picked up his buckets of water. "There's enough water for all of you to take showers," he said, "so long as you don't waste it. I've been busy with other things or I would have had more water carried to the ship." 

	"We'll have to have a pump," Blake said, relieving Taylor of one of the buckets. "There's no use spending time carrying water in buckets." 

	Lenson looked at him sharply to see if he were joking. 

	"Did you take a look at what that diamond silt in the water did to our pump?" he asked. "It ruined it, and it was made of the hardest alloy steel." 

	"We can't use any kind of pump that has moving parts of steel," Blake said. "No steel alloy ever made can resist diamond. And, since steel is our hardest man-made material, it's obvious we can't use any kind of a pump that has metal moving parts. So, we'll not try to fight the diamond with harder steel alloys—if we had them—we'll just overcome the abrasion problem by making a pump that has no moving parts." 

	"Oh?" Cooke stared at him. "A brilliant solution but for one thing—how do we move water without the mover doing any moving?" 

	"We let the water use its own velocity to force part of itself higher than the source—we make a hydraulic ram." 

	"Hm-m-m!" Taylor grunted in self-disgust. "I could have had one made long ago, in my spare time, but I never thought of such a simple solution. I kept thinking of some way to combat the diamond's abrasion, rather than how to avoid it completely." 

	"But a hydraulic ram does have moving parts," Wilfred objected. "The valves. Without the valves alternately opening and closing, the ram wouldn't work. How do you keep valves in it?" 

	"The valves are so simple—one floating valve and one flap valve—that all we have to do is spray the valves and valve seats with plastic rubber. The diamond can't harm rubber—the rubber is so soft that the diamond's hardness has no effect on it." 

* * * 

	A shower and a full meal did much to improve their spirits, and a shave did even more to improve their appearance. Taylor brought up the subject of their next course of action and asked Blake for his opinion of the desirability of further prospecting for uranium. Blake answered the question with a suggestion. 

	"We'll have to rest a week, even though our time is so short," he said. "This time we'll have two deserts to cross, as well as the mountain between, and our past sixty-day diet of food tablets and thorn berries has all four of us in pretty weak condition. While we rest up I suggest we try to think of some alternative to the atomic drive. I won't argue if the rest of you want to continue looking for uranium, but I'm afraid it's hopeless. Without a truck or any other form of transportation, it would do no us good to find the ore. We're not going to be given the time to carry ore for great distances on our backs, across deserts and mountains. So, suppose for the next six days everyone makes a try at thinking up some plan other than the atomic drive?" 

	"The more plans, the better," Taylor said. "If we had a large enough selection to choose from, we could pick out one that would be sure-fire. But I can't see how we can find a quicker and simpler way to lift this ship than the atomic drive." 

	The others felt the same way; they seemed quite willing to consider any alternate plan but with no conception of any such plans. Blake made no mention of the idea in his own mind, certain that it held their only hope for survival but fearing its radical departure from conventional lines of thinking would cause them to reject it, despite the magnitude of its possibilities. 

	They made the hydraulic ram the next day and laid a line of the ship's air tubing to a point sufficiently upstream along the noisy little creek to give the necessary pressure. Shortly before the sun went down they connected the last length of tubing to the ram, then returned to the ship to wait for the first flow of water into the ship's tank. It required some time for the tubing between the ram and the ship to fill with water but the water came at last; a steady little trickle. 

	"You know," Cooke remarked as he watched the tiny flow, "those ancients weren't exactly fools." 

	"At last, we've won one round in our battle with this diamond dust," Lenson said. 

	"I want all of you to keep in mind how we did it," Blake said. "We did it by using the natural forces at hand and by not trying to fight the abrasiveness of the diamond grit. Remember this, in any planning you do—you can't fight diamond with metal!" 

	"I think we're all aware of that by now," Taylor said. 

	"I hope so. Until we acknowledge that fact, we won't get anywhere." 

	No further mention was made of their problem in the succeeding days and Blake hoped that such silence was indicative of serious thinking on their part and not merely a fatalistic acceptance of the status quo. 

	On the sixth day following their return they gathered in the central room of the ship for each to present his plan, if any. Blake procured a few small items from the repair room and his own locker just before the discussion began. 

	Taylor made a quick summary of their predicament. 

	"There could have been only three possible ways of leaving this planet," he said. "The most certain would have been to send a message to New Earth, but that's impossible. We can't repair or duplicate the smashed transmitter tubes or hyperspace transformer. Their construction calls for very complex precision machinery as well as special alloys. We can't re-use the various alloys in the shattered tubes because exposure to the air has turned several of the more delicate alloys to dust. 

	"The second easiest method, and the most impossible, would be to simply wait and hope a ship comes along in time to save us. I know that we all reject that. That leaves only one way of leaving this world before it burns—to make a drive for our ship. And that boils down to the question: Shall we continue to search for uranium and cadmium or shall we devote our time and effort to some other method of lifting the ship than an atomic drive?" 

	"I've kept my mind a receptive blank for six days and not one single idea has come near it," Lenson said. "I don't see where we have any choice—what else can we plan on with any hope at all other than an atomic drive?" 

	"Before we go on to new plans," Wilfred said, "suppose we let Blake give his opinion of the chances of finding uranium and cadmium in time to make a drive." 

	"We haven't found any evidence of any uranium in three full-grown mountain ranges," Blake said. "There's iron, and a small amount of copper, but no radioactive elements. I don't know whether it's true of all this continent, but the section we're on is almost wholly light elements. 

	"I am not in favor of any further prospecting. Our time is very limited; anything we do will have to be done without delay. Further prospecting, on foot, would require time, lots of time. Possibly the ore we want is within fifty miles of us, but how do we find it in time, on foot? Even if we found it, and in a sufficiently pure state, how do we transport it back to the ship in time? We have no truck, you know; we have only our legs and backs. If we had the time—and if this world permitted us to use the truck—I would be in favor of continuing the prospecting until we did find the ores we needed. The truck would shorten days of travel into hours; it would haul needed supplies and equipment to the ore and haul the ore back. But we don't have a truck any more—and we don't have the time. In my own opinion, further prospecting is a waste of our short and precious time." 

	"There doesn't seem to be anyone who disagrees with you," Taylor said when the others remained silent. "You paint a dark picture, but there's no denying the truth of it." 

	"Do you have a plan?" Wilfred asked. 

	"I have. You've all been thinking along conventional lines, haven't you?" 

	"Such conventional lines of thinking produced the ship that brought us here," Wilfred pointed out. 

	"It did, but the same conventional type of thinking is never going to lift it up again. I have an unconventional idea, and a deceptively simple question. If you can answer my question, we'll know how to make a drive for our ship." 

	Blake extracted several items from his pocket: a short steel bar, a square of sheet aluminum, a piece of thin glass and a large darning needle on a long thread. He laid them down on the table before him and continued: 

	"I'm afraid that conventional thinking won't work on an unconventional world. We've all been tackling our problem as though we were marooned on a counterpart of New Earth, with New Earth's dust-free air and plentiful supply of minerals. We keep thinking of a rocket drive because a rocket drive was the simplest type of drive to build on a world of machinery and radioactive ores. We have neither, here; we don't have Earth-type resources and equipment to fight a decidedly non-Earth-type environment. On New Earth we would use machines—all human technological progress stemmed from that simple little thing, the wheel. Without wheels there would never have been machinery, without machinery there would never have been the atomic drive. You've all seen that we can't have wheels on this world. We can't have wheels, we can't have any kind of moving-parts machines on a world of diamond dust. Our own science is built on the wheel and if we don't develop a substitute science for it, we go up in smoke in seven or eight months." 

	Blake picked up the steel bar. "There is one force that no one has mentioned, and it's a force that all the diamond dust on this world could never faze because it has no moving parts—field-type force." 

	He picked up the needle by its thread. "This is a common bar magnet," he said, letting the needle click against the end of it. "We all know that opposite poles attract, like poles repel. I pull the needle off the end of the magnet and the needle snaps back against it the moment I release it because its lower end has been magnetized with a polarity opposite to that of that end of the bar. If I switch ends with the bar magnet, the needle, instead of being attracted to it, will swing away out on the thread to stay away from it. I have a piece of sheet aluminum here—the magnetic repulsion goes right through it. The same with this piece of glass." 

	He laid the magnet and needle back down on the table. "You four have the technical training and knowledge—I'm only a fairly competent mining engineer. But my common sense tells me the reason we can't leave here is because a field-type force, gravity, holds us here. My common sense also tells me that there must be the same basic principles underlying all field-type forces; magnetism, induction, gravity. If two magnetized bodies can be made to repel each other, is it impossible that two bodies held together by gravitational attraction could be made to repel each other? 

	"As I said, I think the same basic principles underlie all field-type forces. If we can learn what that principle is, we can produce a drive that operates by antigravity. So, this is the question I wanted to ask you: What caused the needle and magnet to behave as they did?" 

	There was silence for a while as they considered Blake's proposal. Wilfred was the first to speak. 

	"It's a simple phenomenon," he said, "and known to any child." 

	"That's true," Blake agreed. "Any child knows what a magnet will do, but do any of you know any more about a magnet than the hypothetical child? You all know what a magnet will do—do any of you know why it does it?" 

	"I know nothing of magnetic forces, myself," Lenson said, somewhat uncertainly, "since they don't enter my own field of study, but Cooke probably knows them from A to Izzard." 

	"I know what a magnet will do—I don't really know why it does it," Cooke said. "Men have made use of magnetism and induction forces for centuries and the behavior of such forces is known in precise detail—but still no one knows just what these forces are. You can manipulate a force to your own advantage if you understand its behavior under various conditions, but if you understand exactly what that force is, you can manipulate it to your own advantage much more efficiently." 

	"I agree," Lenson said. 

	"There's another field-type force we use without fully understanding it—our hyperspace drive," Blake said. "Theoretically, it shouldn't require such an enormous surge of power to activate the space-shift units—but we have to use that enormous surge of power to get any results. We say we 'slip' or 'jump' into hyperspace. We don't. We don't 'slip' through that barrier—we smash our way through it with the full output of a nuclear converter. If we can learn what field-type forces are, I see no reason why we might not be able to so alter our hyperdrive that the ship's generator will supply more than enough power for it." 

	"A possibility," Cooke said. 

	Taylor nodded in agreement, then said, "But, while the idea has unlimited possibilities, we haven't the slightest assurance that we'll realize any of them in the short time we have."

	"I know it," Blake said. "I know it's a long chance, since our time is so short. But it is a chance, and all the other plans would have been doomed to failure before we started."

	"It's something of a challenge," Wilfred said. "The idea appeals to me. It's true that we actually know relatively little of field-type forces; our environment was such that our technical progress led to atomic study."

* * *

	Blake looked the four men over, both surprised and relieved that they should accept his plan without argument; the only possible approach to the problem, he was convinced, that offered any hope. Taylor seemed to be the only one who had any doubts and Blake said to him, "What is your own opinion of my plan? Are you in favor of dropping all other plans and concentrating on the study of field-type forces?"

	"My half-expressed doubts about accomplishing anything in the time we have weren't intended as an objection. It's a field of study of which we know very little, and it's a difficult field to learn. But I'm in favor of it—it, at least, isn't dependent upon the use of moving machinery. We can study it under controlled conditions, here in the ship. In fact, I would like to suggest the study of induction fields as a starter—we can manipulate induction fields to suit ourselves, and under all kinds of conditions."

	"In all of Man's history," Cooke said, "since the first savage wondered why a piece of natural lodestone would attract grains of magnetite, no one has been able to discover why. But, while we don't have much time, we have a very powerful incentive. And we do know a few things about magnetism. For example: all ferrous iron with a valence of two is magnetic. Ferric iron, with a valence of three, is not magnetic. Let's find out why—an atom of iron is an atom of iron and should be magnetic whether it's combined with oxygen or not." 

	"We'll need juice," Taylor said. "Plain, old-fashioned electricity." 

	"We can manage that," Blake said. "The ship's generator wasn't damaged, so we'll make the only kind of engine a world without oil, coal or radioactive ores would have permitted—a steam engine. We have water, plenty of trees for fuel, and we have a lathe. There's a spare primer-thrust tube that will make a perfect cylinder." 

	"How about the diamond dust in the water?" Taylor asked. 

	"Only clean steam will go to the cylinder, and the diamond dust won't affect the boiler as lime would. Besides, we have our water filters on the ship's tanks." 

	Wilfred picked up the needle and let it swing from the thread, holding the magnet under it. "If this magnet represented this planet, and its magnetism was the force of gravity, with this needle representing our ship, fitted with some gadget to make it antigravitic at the lower end as this needle is antimagnetic—" 

	He let the needle swing on the thread, bouncing away from the repulsion of the magnet, then swinging in again, to be stopped and driven away by the invisible force. 

	"The invisible barrier," he said. "What is it? It isn't matter—not as we know matter. We call it a force, but just exactly what is it that no material—glass, metal or anything else—can bar?" 

	"That's the question," Taylor said. "It's going to be a hard one to answer." 

	"It will," Cooke said, "but we know the answer is there if we can find it. The power we need to move this ship is all around us; we'll be looking for the secret of a power that we know exists." 

	"And if we continued to hunt for uranium, we'd be looking for something that all the evidence shows does not exist," Blake said. 

	Lenson shoved back his chair and got to his feet. "Now that we know what we want to do, let's get busy," he said. "It will take all five of us quite a while to build that boiler and engine, so let's get started right now." 

	"I agree," Cooke said. "We're headed for an unpleasant end at a hundred miles a second—the Bird of Time has but a little way to fly—"

	"And Lo!—the Bird is on the Wing!" Wilfred finished, a rare smile on his pugnacious young face as he shoved back his own chair.

* * *

	The generator was lowered from its hanging position on the wall and fastened to a new-laid flooring of steel. A gear box was made from the gears of the ship's elevator and the portholes of the drive room were equipped with glassite windows; windows which were rendered sub-translucent by the first sandstorm, but would still admit sufficient light for working. The boiler and engine construction progressed slowly, with the small lathe and the limited kinds of material available, but they worked steadily while the yellow star advanced farther and farther ahead of their own sun. It gleamed in the dawn sky a full hour in advance of the rising of their sun when they began the building of the engine. On the day they completed the engine it was dispelling the eastern blackness two hours before the blue-white sun brought the first touch of the rainbow dawn and almost three hours before the sun, itself, appeared. 

	Blake, Cooke and Lenson toasted the steam engine on the day they completed it and gave it a successful trial run; a modest toast of one small glass each, due to the limited amount of grain alcohol in the medicine locker. Taylor and Wilfred, who never drank, had already gone into the central room to begin the job of converting it into a laboratory. 

	"She's not pretty," Cooke said, indicating the shapeless boiler and engine with his empty glass, "but beauty is as beauty does. And she spun that generator like a top." 

	"She did," Lenson said. "As you said of the hydraulic ram—those old-timers weren't exactly fools." 

	"We have all the power we need whenever we happen to need it," Blake said. "Next, as soon as we get the central room converted, will be to put our ideas to the acid test." 

	"They say the acid test is always sour," Cooke said. "We'll have to make an exception of that rule. And have you noticed our big yellow star? It's over forty degrees in advance of our sun, now—gives the illusion of traveling away from our sun, except that it keeps getting brighter." 

	"We're already a fifth of the way to it," Blake said. "The nova created when Aurora goes into the yellow sun should be spectacular," Cooke went on. "And then what happens when our big blue-white sun goes into the nova? Will it produce a super-nova? No man has ever stood off and seen such a thing, you know."

	"Neither will we if we don't get busy," Lenson said. "Time, tide and Aurora's rendezvous wait for no man—and here we stand with empty glasses in our hands when we should be working."

	"You're right," Cooke said, turning to go. "Holding an empty glass is about the most useless thing a man ever did."

* * *

	The central room of the ship was converted into a laboratory—or as near to a laboratory as their limited equipment would permit—and large glassite windows were fitted into holes cut in the hull; a much better form of illumination than the improvised oil lamps they had been using. 

	Ideas were presented in the days to come; some that were no more than the repetition of known experiments and some that were contrary to accepted theories of magnetic and gravitic principles. The latter were, at first, presented somewhat self-consciously and Blake and Cooke did their best to discourage such reluctance to depart from conventional thinking. As the days merged into scores of days the reluctance to present unorthodox theories vanished and they all five adopted the policy of accepting each new theory with, as Cooke put it: "The assumption that every theory, no matter how fantastic, is innocent of the crime of invalidity until proven guilty." 

	Each experiment was given a number, preceded by the letter X for "Experimental," and the data gained by the experiment filed away. Blake, whose mathematical computations as a mining engineer had never required more than trigonometric and logarithmic tables, became as proficient as the others. His lack of advanced technical learning was, in a way, no disadvantage—he had nothing to unlearn. He absorbed all the data available concerning the actual, observed behavior of field-type forces and rejected the adoption of any preconceived theories of the causes for such behavior, keeping his mind open for the unbiased inspection of new concepts. 

	Thirty days passed and then another thirty, while the yellow star grew slowly brighter and widened the apparent distance between itself and their own sun—the apparent widening of the distance that was so belied by the yellow star's increasing brightness. The first enthusiasm of Cooke, Lenson and Wilfred gave way to a quietness and they worked longer hours. Taylor betrayed no particular emotion but he was up early and to bed late. 

	Summer solstice came and the sun ceased its apparent northward progress and began to creep to the south, almost imperceptibly at first. The desert winds came with greater frequency after solstice, hot and searing and bringing their ever-present burden of sand and dust. 

	They had been on Aurora four months when Cooke, in a moment of grim humor, chalked a huge calendar on the wall of the laboratory. He made it thirty days wide and five rows deep. Each day that passed would be filled in with red chalk and the red squares would move across the calendar, row upon row, warning the five men who labored in the room of the shortness of their time. 

	Two lines of thirty days each were chalked a solid red when they found the first key to the secret that meant their lives.

* * *

	X117 lay on the laboratory table, a complex assembly of coils and electronic apparatus, with a small blue-white diamond swinging in a tiny arc just within the focal point of the induction fields. The diamond hung on a long thread, attached to a delicate spring scale with a large dial. 

	Cooke glanced over the assembly, then raked his heavy hair back from his face and grinned at the others. "This," he said, "should be what we've been looking for." 

	"You've said that every time," Wilfred reminded him. 

	"Let's find out," Blake suggested, feeling his usual impatience to learn as soon as possible if their efforts had again been in vain. "We have full steam pressure and our engine is ready to spin the generator whenever you close the switch." 

	"That's what I say—let's get the suspense over with," Lenson said. He closed the switch that would open the steam engine's governors and the faint chuffing of it in the drive room became a fast pounding. The needle on the generator output gauge began to climb rapidly and all eyes were transferred to the dial of the spring scale. 

	"Twenty seconds," Cooke said, his attention alternating between the diamond and his watch. "It should have built up an effect by then. If it hasn't, it will look like another failure and I'll have to guess again on the success of the next one." 

	No one else spoke as they watched the diamond swing gently from the long thread. It was only a small one, not more than ten grains in weight; such a small and insignificant mass to resist all their efforts to move it. 

	"Ten seconds," Cooke intoned. "Eight—cross your fingers and say a little prayer—three—two— now!" 

	The diamond continued to swing in its tiny arc and the pointer on the scale remained motionless. No one moved nor took their eyes off the diamond, even when the smell of scorched insulation became noticeable. 

	"It's overloaded, now," Lenson said, but made no move to open the switch. 

	"Give it more," Blake ordered. "Give it the full output of the generator—let's be sure of it, and let it burn if it wants to." 

	Lenson snapped another switch shut and the full output of the big generator surged through X117. A coil went out in a flash of blue fire and someone cried out incredulously. 

	In the brief instant before the coil disappeared the diamond moved—up. 

	"It moved!" Cooke exclaimed jubilantly. "We're going to have our drive!" 

	There was a minute of quite natural elation and confused babble of excited talk during which Blake remembered to open the switch again. The muted pounding of the steam engine died away and the babble resolved itself into coherent conversation. 

	"We're on the right track, at last," Blake said decisively. 

	"We've just done something all our science has never before accomplished," Wilfred said. "We've created a force of antigravity." 

	"We have a long way to go," Taylor said. "We've built up a force of antigravity that lifted a diamond weighing ten grains—and it took the full output of our ship's generator to do it. But we now have a proven result to go on; we have the beginning of an understanding of the basic principles." 

	"When we get it where we want it, I doubt that it will bear any resemblance to this," Blake said, indicating the assembly on the table with his hand. "This just happened to be the easiest way to produce a little of the force we were looking for. Like, you might say, the easiest way to produce electricity is to stroke a cat. But you wouldn't try to supply electricity for a city by having a million men engaged in stroking a million cats." 

	"I have a theory," Cooke said. "Once we learn a little more about this force we created we can try something else—we'll try reversing the gravitic flow, rather than building up a counter-flow. I want to work on that theory and see what the rest of you think of it. Such a system should require almost no power since no force would be created, merely reversed." 

	"The perfect ship's drive would be a field-type drive," Wilfred said, "for more reasons than one. The reason I have in mind at the moment is this: there would be no limit to the speed of acceleration since the ship and its occupants would be enveloped in the driving force. It wouldn't, to the passengers, be like the rocket drive where they're actually pushed along by the seat of their pants." 

	Blake nodded. "I've been thinking of the same thing. I suppose we all have, because the only way we're going to escape that nova is to accelerate at an unheard-of velocity. We can do that when we perfect what we're working on; with our ship and ourselves enveloped in the driving force we can accelerate immediately to any speed, and with no sensation of accelerating at all." 

	"No more acceleration hammocks and anti-acceleration drugs," Cooke said. "No more long periods of reaching maximum acceleration, then other long periods of decelerating. We really have something—or will have when we're through." He looked over at Taylor. "How much time to we have? Did your latest observations give us as much as a day more?" 

	Taylor glanced at the calendar Cooke had chalked on the wall. "Your calendar still holds good—the last day you have on it will be our last day." 

	"Eighty-five days—that's not many," Lenson said. 

	"No, but we're going to make progress from now on," Blake said. "We have something to work on; we've opened a door that no one has ever opened before." 

	"And if there's another door behind the one we opened?" Lenson asked. 

	It was Cooke who answered, the finality of conviction in his voice. "Then we'll open that one, too." 

* * * 

	Lenson's question proved to be not an idle one; there was a door behind the one they had opened. In the countergravity they had created lay the key to the second door, the reversal of gravity, but it eluded them as the days went by. They repeated X117 and variations of it until the experimental-data record bore the number, X135. Cooke's theory was examined and re-examined and no fallacy could be found, neither could any other theory be constructed that would fit the facts they had discovered. They accepted Cooke's theory as valid, and no one questioned the possibility of reversing gravitic flows with a negligible amount of power. 

	All were convinced of ultimate success—if they could but have the time. The days fled by while they tried and tried again. They worked longer hours, all of them thinner and the bulldog stubbornness on Wilfred's face becoming more pronounced. The yellow star crept farther ahead of their own sun, growing brighter as it went, and the red-chalked squares marched across the calendar. Their determination increased as their days of grace melted away; a determination expressed by a silent intensity of effort by all but Cooke, whose intensified efforts were accompanied by considerable cheerful speculations upon the many pleasures New Earth would have to offer them on their return. Blake wondered if Cooke's faith in their eventual success was as firm as he insisted, or if it was only a psychological attempt to improve not only the morale of the others but also his own. The red squares had crept across two more rows and over half-way across a third when he got his answer.

* * *

	It was on the morning following the failure of X144. They had worked far into the night to complete the assembly of it and it had been devoid of observable results. The others had gone to bed to get a few hours sleep before starting the construction of X145 but Blake had found sleep impossible. The failure of X144 exhausted every possibility but one; the one represented by the to-be-constructed X145. Theoretically, X145 would be successful—but some of the others had been theoretically certain of success until their trial had revealed hitherto unknown factors. After an hour of the futile wondering and conjecturing, Blake had given up the thought of sleep and put on his clothes. He walked down to the creek, marveling again at the beauty of a world so harsh and barren. The yellow star, now bright enough to cast his shadow before him, was low in the west as he walked up the creek and the eastern sky was being touched with the first emerald glow that preceded the rainbow banners. When the sun came up it would bring another day of heat, and the dry, swirling winds would send the diamond dust along in low-flying clouds. But in the quiet of early dawn it was cool and pleasant along the creek with the trees bordering it making a leafy green corridor along which he walked into the emerald dawn while the fresh scent of green, living things was about him. He saw the bulk of something red, lying in the sand beside a tree, and he went over to it. It was a small mound of blood-red diamonds, and he saw that someone had selected them for their flawless perfection. He squatted beside them, leaning back against the tree trunk and lighting a cigarette as he wondered idly who had placed them there, and why. He forgot them as he rested and watched the emerald of the eastern sky glow deeper in color and the first touch of iridescence come to it. Aurora, for all her grimness, was a beautiful world, and along the creek a man could almost imagine he was on New Earth but for the glory of the dawn and the glitter of the diamond sand. The leaves of the tree over him rustled softly, and among the fresh green smells there came the scent of the red flowers that grew along the water's edge; a scent that brought a brief, nostalgic memory of the old-fashioned briar roses in his mother's garden when he was a boy. She had brought the seeds from Old Earth when she was a girl and on Old Earth, she had told him, they grew wild. 

	It was hard to believe, as he sat beside the creek, that it and the sweet-scented flowers and the leaves rustling overhead were not things of some stable world where they would remain so for uncounted lifetimes to come; where only the slow, slow dying of the sun could at last bring the end. 

* * * 

	Gravel crunched behind him and he turned to see Cooke. "Nice here, isn't it?" Cooke asked, sitting down near him. Blake nodded, then said, "I thought you were in bed?"

	"And I thought you were," Cooke replied. "What do you think of the quality of the diamonds there beside you?"

	"You're the one who piled them here?" Blake asked, surprised. "How long has this been going on, and why?" 

	"Ever since I said we'd unlock that second door. We may have to leave here in a hurry, but we are going to leave here. I just did the logical thing of using some of my spare minutes to pile up some of the choicest diamonds where we can get them in short order." 

	"Do you really believe that, or is this diamond-gathering just to bolster your confidence?" Blake asked, watching him curiously. 

	"What do you think?" Cooke countered. 

	Blake studied him, the hard jaw and broken nose, the glittering black eyes, and saw that they were not deceptive, after all. Under ordinary circumstances Cooke was easy-going and genial, but now the mask of good humor had fallen away for the moment and the hard steel core of the man was revealed. Cooke, like the bulldog Wilfred, would be stubbornly defying their fate when Aurora went into the yellow sun. 

	Yet, though such stubborn faith might prove to be in vain, it had its advantages. Stubborn men die hard—sometimes it takes more than merely impossible difficulties to persuade a stubborn man to die at all. 

	"I think you have the right idea," Blake said. 

	There was a silence as Blake returned his attention to the dawn, then Cooke remarked, "We won't have but a few more like that—before we leave here, one sun or the other will be in view all the time. 

	And, by then, the yellow one will be too bright to permit any sunrise effects from the other one." 

	"Aurora doesn't have many days left." 

	"What a show that will be!" Cooke mused. "First a nova as Aurora goes into the yellow sun, then the big blue-white sun will go into the nova." Then he sighed and said, "But I sort of hate to see it. I don't care about the suns, but I hate to see Aurora go up in a blaze, no matter how glorious that blaze may be. She's a hard world on humans, but she forced us to pull ourselves up by our own bootstraps. She's a beautiful little devil and I hate to see her destroyed." 

	The good die young, Blake thought, watching the dawn flame into vivid, fiery life. Not that Aurora was good. She was cruel and beautiful; she was a splendid, glittering prison taking them with her on her swift, silent flight to extinction. 

	It was not the way a world should die. The death of a world should come only when the fires of her sun went out. A world should grow old and cold for millennia upon millennia; death should come slowly and quietly like that of an old, old woman. But it would not be so for Aurora; for her death would be quick and violent and she would explode a yellow sun into a nova as she died. 

* * *

	Two days later they were ready to put X145 to the test. It was similar to the long-past X117 in that the same blue-white diamond swung from the same long thread, but the assembly was of a different form and the steam engine was cold. They had made a battery, a simply storage battery, and X145 would either succeed or fail with the battery's small current. 

	The tension was far greater than it had ever been at any previous test, and even Cooke had no cheerful smile or remarks. X145 would be the test; if it failed all their labors leading up to it had been to a dead-end. And they would have no time to try another approach. 

	"I guess we're ready," Cooke said. Blake went to the rheostat that controlled the amount of current and the others grouped about the X145 assembly. 

	"I'll give it the juice gradually," Blake said. "Although if it as much as quivers at full current, we really will have our drive." 

	Blake watched the diamond as he turned the rheostat's knob. He felt the faint click of it as it made first contact, then flinched involuntarily as something cracked like a pistol shot and the diamond, thread and scale vanished. Something clattered to the floor across the room and Lenson's surprised question was cut off by a shout from Cooke: "Look—the scale!" 

	He ran to where it had fallen and picked it up, holding it for all to see. There was a hole torn through it. 

	"How much . . . how much power did you give it?" he demanded of Blake. 

	"Minimum current," Blake replied. 

	"Minimum current," Wilfred murmured. "Minimum current—and it shot the diamond through the scale!" 

	The torn scale was passed from hand to hand and the talk it engendered was both voluble and optimistic. 

	Cooke hurried out after another scale and Blake and Lenson connected another rheostat in series with the first, then added still another when Wilfred gave the results of his calculations on the slide rule. 

	Cooke returned with the scale, a much larger one, and a block of copper. "Three?" He lifted his eyebrows toward the three rheostats. "If we can budge a pound of copper with full current through three rheostats, then we can lift a thousand ships with our generator." 

	The copper block was suspended from the scale, to swing down in the field of the X145, and Blake said, "I'll try minimum current again, even though it may not be enough to affect it at all. We can't expect it to do anything spectacular at minimum current, I'm sure." 

	He turned the rheostat knob a fraction of an inch and felt the faint click, his eyes on the copper block. There was a roar, sharp and deafening in the room, and the copper block vanished as the diamond had. A hard pull of hot air struck him and something ricocheted back down from the roof to strike him painfully on the shoulder, a fragment of metal from the scale. Wilfred was pointing upward, yelling something. " . . . Through the roof!" 

	Blake looked up and saw what he meant; there was a small hole torn through the hull of the ship over their heads, a hole such as would be made by a one-pound block of copper. 

	"Three rheostats," Cooke exclaimed. "We not only have the power to lift our ship; we could lift ten thousand of them!" 

	Cooke began to make rapid calculations and Wilfred followed suit. Blake, curious though he was, saw no reason for three of them to work simultaneously on the same problem so he waited, as did Taylor and Lenson. Taylor was smiling; the first time in many days he had seen the old man smile. 

* * * 

	"The problem of power for the hyperspace drive no longer exists," Lenson said. "We can apply the same principles to its alteration that we just now made use of and we can actually 'slip' through the barrier rather than bulldozing our way through it." 

	"We have a means of driving our ship and we have a means of slipping her into hyperspace," Blake said. "We've come mighty near to succeeding in our plans—will we have the time to succeed all the way?" 

	"Time?" Lenson looked surprised. "How much time do you want? We have seven days. Isn't that enough?" 

	Blake shook his head. "We can't have the ship ready in that short space of time. To leave here within seven days we'll have to—" 

	"Did I say ten thousand ships?" Cooke's black eyes glittered with exultation. "We could move a world with the power in that generator!" 

	"We've really reversed the gravitic flow," Wilfred said, as enthused as Cooke. "The only power required to move an object is that for the reversing field—or whatever we should call it. This power requirement is negligible with a capital N." 

	"Homeward bound!" Cooke said. "Safe and snug beyond the nova's reach in hyperspace!" 

	"If we want to give up the habit of breathing," Blake pointed out. 

	The four of them stared at him, and one by one their faces fell as they realized what he referred to; the thing they had forgotten in the intensity of their efforts to devise a drive. 

	"The ship—" Cooke was the first to express the thought in the minds of all of them. "It leaks like a sieve!" 

	"How, in seven days, can we finish cutting the two halves of the ship apart, wall in the cut-off end and repair all the broken-apart seams?" Blake asked. 

	"We can't," Taylor said. He sat down, suddenly old and tired, his former cheerfulness gone. "I don't see how we could make the ship leak-proof in less than four months with the tools and materials we have." He smiled again, but without mirth. "But we came close to succeeding, didn't we?" 

	"We'll succeed," Blake said. "It's a tough problem, apparently, but I have an idea." 

	"How about enclosing the ship in a gravitic field large enough to hold its air by plain gravity?" Wilfred asked. 

	"And how big a field would that have to be?" Lenson asked. 

	"Big," Blake said. "Even in hyperspace, it will take us six months to get home—or near that. Air has a tendency to leak away and dissipate into space rather easily. I doubt that we could enclose the ship in a field large enough to hold enough air to last us for six months—as I say, it leaks away into space very easily." 

	"The gradual loss of our air would be an unpleasant way to die," Cooke said. "The ship leaks, we don't have the time to repair it, so what do we do? How do we solve that last little problem?" 

	"Seven days to do a four months' repair job—" Lenson sat down beside Taylor and sighed. "It looks like we can't make our ship leak-proof in the time we have. But surely there is some way—" 

	"There is," Blake said. "We have a perfect method of both getting home and keeping air in our ship. It should be obvious to all of you." 

	Questioning looks gave way to dawning comprehension. There was a long silence as they considered the plan, then Cooke said, "After all, a fortune was what we set out for." 

	"We'll have to call them in advance," Wilfred said. "We can't just barge in." 

	Blake nodded. "Homeward bound, safe and snug in hyperspace—but, as you say, we'll have to radio them in advance. If we just barreled in without giving them a chance to tell us where to park, it could raise merry hell with everything." 

* * * 

	Redmond, control-tower radio operator of Spaceport 1, New Earth, was puzzled. He scratched his thinning hair and leaned closer to the speaker. The voice from it came in distinctly, but faintly. "Can't you step up your volume?" he asked. "No," the tiny voice answered. "I told you we had to couple in the driver stage—our power stage is gone."

	"How far out are you?" Redmond asked. "About a billion miles. Did you get what I told you? This is the Star Scout and we're just back from beyond the Thousand Suns. We were going to get caught by a nova—"

	"I got everything," Redmond interrupted. "Your planet was going into the yellow sun and its high carbon content would create a nova. You learned how to control field-type forces so that you would have a drive for your ship. So you came back to New Earth—or a billion miles out from it. But why do you keep insisting that I have my superiors engage an astrophysicist to tell you where to park your ship? And another thing—you said it would take four months to make your ship leak-proof and you only had seven days. How did you do a four months' job in seven days?"

	"We didn't," the thin voice from the speaker answered. "That's what I'm trying to tell you and that's why we'll have to have an astrophysicist define our parking place. We didn't have time to repair our ship, and we couldn't enclose it in a gravitic field large enough to hold air for six months." Redmond clutched his thinning hair again, feeling suddenly dizzy. "You don't mean—"

	"Yeah. We brought the planet with us." 

The End