"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 gla.s.site 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 gla.s.s 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 gla.s.s, "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 gla.s.ses in our hands when we should be working."

"You're right," Cooke said, turning to go. "Holding an empty gla.s.s 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 gla.s.site 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 repet.i.tion 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 a.s.sumption 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 pa.s.sed 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 pa.s.sed 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 a.s.sembly 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 a.s.sembly, 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 ma.s.s 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 a.s.sembly 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 pa.s.sengers, 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 p.r.o.nounced.

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 a.s.sembly 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 circ.u.mstances 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 a.s.sembly 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 a.s.sembly.

"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 k.n.o.b. 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 pa.s.sed 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 k.n.o.b 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!"