Part 3

"I think," said Riki quietly, "that you're telling me that after all we can't store up heat to live on, down in the mine."

"We can't," agreed Massy grimly. "Not much, nor long. Not enough to matter."

"So we won't live as long as Ken expects?"

"Not nearly as long," said Massy evenly. "He's hoping we can find out things to be useful back on Lani II. But we'll lose the power we can get from our grid long before even their new grids are useless. We'll have to start using our reserve power a lot sooner. It'll be gone--and us with it--before they're really in straits for living-heat."

Riki's teeth began to chatter.

"This sounds like I'm scared," she said angrily, "but I'm not! I'm just freezing! If you want to know, I'd a lot rather have it the way you say! I won't have to grieve over anybody, and they'll be too busy to grieve for me! Let's go inside while it's still warm!"

He helped her back into the cold-lock, and the outer door closed. She was shivering uncontrollably when the warmth came pouring in.

They went into Herndon's office. He came in as Riki was peeling off the top part of her cold-garments. She still shivered. He glanced at her and said to Massy:

"There's been a call from the grid-control shack. It looks like there's something wrong, but they can't find anything. The grid is set for maximum power-collection, but it's bringing in only fifty thousand kilowatts!"

"We're on our way back to savagery," said Massy, with an attempt at irony.

It was true. A man can produce two hundred and fifty watts from his muscles for a reasonable length of time. When he has no more power, he is a savage. When he gains a kilowatt of energy from the muscles of a horse, he is a barbarian--but the new power cannot be directed wholly as he wills. When he can apply it to a plow he has high barbarian culture, and when he adds still more he begins to be civilized. Steam power put as much as four kilowatts to work for every human being in the first industrialized countries, and in the mid-twentieth century there was sixty kilowatts per person in the more advanced nations. Nowadays, of course, a modern culture assumed five hundred as a minimum. But there was less than half that in the colony on Lani II. And its environment made its own demands.

"There can't be any more," said Riki, trying to control her shivering. "We're even using the aurora and there isn't any more power. It's running out. We'll go even before the people at home, Ken."

Herndon's features looked very pinched.

"But we can't! We mustn't!" He turned to Massy. "We do them good, back home! There was panic. Our report about cable-grids has put heart in people. They're setting to work--magnificently! So we're some use! They know we're worse off than they are, and as long as we hold on they'll be encouraged! We've got to keep going somehow!"

Riki breathed deeply until her shivering stopped. Then she said calmly:

"Haven't you noticed, Ken, that Mr. Massy has the viewpoint of his profession? His business is finding things wrong with things. He was deposited in our midst to detect defects in what we did and do. He has the habit of looking for the worst. But I think he can turn the habit to good use. He did turn up the idea of cable-grids."

"Which," said Massy, "turns out to be no good at all. They'd be some good if they weren't needed, really. But the conditions that make them necessary make them useless!"

Riki shook her head.

"They are useful!" she said firmly. "They're keeping people at home from despairing. Now, though, you've got to think of something else. If you think of enough things, one will do good the way you want--more than making people feel better."

"What does it matter how people feel?" he demanded bitterly. "What difference do feelings make? Facts are facts! One can't change facts!"

Riki said with no less firmness:

"We humans are the only creatures in the universe who don't do anything else! Every other creature accepts facts. It lives where it is born, and it feeds on the food that is there for it, and it dies when the facts of nature require it to. We humans don't. Especially we women! We won't let men do it, either! When we don't like facts--mostly about ourselves--we change them. But important facts we disapprove of--we ask men to change for us. And they do!"

She faced Massy. Rather incredibly, she grinned at him.

"Will you please change the facts that look so annoying just now, please? Please?" Then she elaborately pantomimed an over-feminine girl's look of wide-eyed admiration. "You're so big and strong! I just know you can do it--for me!"

She abruptly dropped the pretense and moved toward the door. She half-turned then, and said detachedly:

"But about half of that is true."

* * * * *

The door slid shut behind her. Massy thought bitterly, _Her brother admires me. She probably thinks I really can do something!_ It suddenly occurred to him that she knew a Colonial Survey ship was due to stop by here to pick him up. She believed he expected to be rescued, even though the rest of the colony could not be, and most of it wouldn't consent to leave their kindred when the death of mankind in this solar system took place. He said awkwardly:

"Fifty thousand kilowatts isn't enough to land a ship."

Herndon frowned. Then he said:

"Oh. You mean the Survey ship that's to pick you up can't land? But it can go in orbit and put down a rocket landing-boat for you."

Massy flushed.

"I wasn't thinking of that. I'd something more in mind. I ... rather like your sister. She's ... pretty wonderful. And there are some other women here in the colony, too. About a dozen all told. As a matter of self-respect I think we ought to get them away on the Survey ship. I agree that they wouldn't consent to go. But if they had no choice--if we could get them on board the grounded ship, and they suddenly found themselves ... well ... kidnaped and outward-bound not by their own fault.... They could be faced with the accomplished fact that they had to go on living."

Herndon said evenly:

"That's been in the back of my mind for some time. Yes. I'm for that. But if the Survey ship can't land--"

"I believe I can land it regardless," said Massy doggedly. "I can find out, anyhow. I'll need to try things. I'll need help ... work done. But I want your promise that if I can get the ship to ground you'll conspire with her skipper and arrange for them to go on living."

Herndon looked at him.

"Some new stuff--in a way," said Massy uncomfortably. "I'll have to stay aground to work it. It's also part of the bargain that I shall. And, of course, your sister can't know about it, or she can't be fooled into living."

Herndon's expression changed a little.

"What'll you do? Of course it's a bargain."

"I'll need some metals we haven't smelted so far," said Massy. "Potassium if I can get it, sodium if I can't, and at worst I'll settle for zinc. Cesium would be best, but we've found no traces of it."

Herndon said thoughtfully:

"No-o-o. I think I can get you sodium and potassium, from rocks. I'm afraid no zinc. How much?"

"Grams," said Massy. "Trivial quantities. And I'll need a miniature landing-grid built. Very miniature."

Herndon shrugged his shoulders.

"It's over my head. But just to have work to do will be good for everybody. We've been feeling more frustrated than any other humans in history. I'll go round up the men who'll do the work. You talk to them."

* * * * *

The door closed behind him. Massy very deliberately got out of his cold-clothing. He thought, _She'll rave when she finds her brother and I have deceived her._ Then he thought of the other women. _If any of them are married, we'll have to see if there's room for their husbands. I'll have to dress up the idea. Make it look like reason for hope, or the women would find out. But not many can go_--

He knew very closely how many extra passengers could be carried on a Survey ship, even in such an emergency as this. Living quarters were not luxurious, at best. Everything was cramped and skimped. Survey ships were rugged, tiny vessels which performed their duties amid tedium and discomfort and peril for all on board. But they could carry away a very few unwilling refugees to Kent IV.

He settled down at Herndon's desk to work out the thing to be done.

It was not unreasonable. Tapping the ionosphere for power was something like pumping water out of a pipe-well in sand. If the water-table was high, there was pressure to force the water to the pipe, and one could pump fast. If the water-table were low, water couldn't flow fast enough. The pump would suck dry. In the ionosphere, the level of ionization was at once like the pressure and the size of the sand-grains. When the level was high, the flow was vast because the sand-grains were large and the conductivity high. But as the level lessened, so did the size of the sand-grains. There was less to draw, and more resistance to its flow.

But there had been one tiny flicker of auroral light over by the horizon. There was still power aloft. If Massy could in a fashion prime the pump: if he could increase the conductivity by increasing the ions present around the place where their charges were drawn away--why--he could increase the total flow. It would be like digging a brick-well where a pipe-well had been. A brick-well draws water from all around its circumference.

So Massy computed carefully. It was ironic that he had to go to such trouble simply because he didn't have test-rockets like the Survey uses to get a picture of a planet's weather-pattern. They rise vertically for fifty miles or so, trailing a thread of sodium-vapor behind them. The trail is detectable for some time, and ground-instruments record each displacement by winds blowing in different directions at different speeds, one over the other. Such a rocket with its loading slightly changed would do all Massy had in mind. But he didn't have one, so something much more elaborate was called for.

_She'll think I'm clever_, he reflected wryly, _but all I'm doing is what I've been taught. I wouldn't have to work it out if I had a rocket._

Still, there was some satisfaction in working out this job. A landing-grid has to be not less than half a mile across and two thousand feet high because its field has to reach out five planetary diameters to handle ships that land and take off. To handle solid objects it has to be accurate--though power can be drawn with an improvisation. To thrust a sodium-vapor bomb anywhere from twenty to fifty miles high--why--he'd need a grid only six feet wide and five high. It could throw much higher, of course. It could hold, at that. But doubling the size would make accuracy easier.

He tripled the dimensions. There would be a grid eighteen feet across and fifteen high. Tuned to the casing of a small bomb, it could hold it steady at seven hundred and fifty thousand feet--far beyond necessity. He began to make the detail drawings.

* * * * *

Herndon came back with half a dozen chosen colonists. They were young men, technicians rather than scientists. Some of them were several years younger than Massy. There were grim and stunned expressions on some faces, but one tried to pretend nonchalance, and two seemed trying to suppress fury at the monstrous occurrence that would destroy not only their own lives, but everything they remembered on the planet which was their home. They looked almost challengingly at Massy.

He explained. He was going to put a cloud of metallic vapor up in the ionosphere. Sodium if he had to, potassium if he could, zinc if he must. Those metals were readily ionized by sunlight--much more readily than atmospheric gases. In effect, he was going to supply a certain area of the ionosphere with material to increase the efficiency of sunshine in providing electric power. As a sideline, there would be increased conductivity from the normal ionosphere.

"Something like this was done centuries ago, back on Earth," he explained carefully. "They used rockets, and made sodium-vapor clouds as much as twenty and thirty miles long. Even nowadays the Survey uses test-rockets with trails of sodium-vapor. It will work to some degree. We'll find out how much."

He felt Herndon's eyes upon him. They were almost dazedly respectful. But one of the technicians said coldly:

"How long will those clouds last?"

"That high, three or four days," Massy told him. "They won't help much at night, but they should step up power-intake while the sun shines on them."

A man in the back said crisply:

"Hup!" The significance was, "Let's go!" Then somebody said feverishly, "What do we do? Got working drawings? Who makes the bombs? Who does what? Let's get at this!"

Then there was confusion, and Herndon had vanished. Massy suspected he'd gone to have Riki put this theory into dot-and-dash code for beam-transmission back to Lani II. But there was no time to stop him. These men wanted precise information, and it was half an hour before the last of them had gone out with free-hand sketches, and had come back for further explanation of a doubtful point, and other men had come in hungrily to demand a share in the job.

When he was alone again, Massy thought, _Maybe it's worth doing because it'll get Riki on the Survey ship. But they think it means saving the people back home!_

Which it didn't. Taking energy out of sunlight is taking energy out of sunlight, no matter how you do it. Take it out as electric power, and there's less heat left. Warm one place with electric power, and everywhere else is a little colder. There's an equation. On this colony-world it wouldn't matter, but on the home world it would. The more there was trickery to gather heat, the more heat was needed. Again it might postpone the death of twenty million people, but it would never, never, never prevent it.

* * * * *

The door slid aside and Riki came in. She stammered a little.

"I ... just coded what Ken told me to send back home. It will ... it will do everything! It's wonderful! I ... wanted to tell you!"

Massy writhed internally. It wasn't wonderful.

"Consider," he said in a desperate attempt to take it lightly, "consider that I've taken a bow."

He tried to smile. It was not a success. And Riki suddenly drew a deep breath and looked at him in a new fashion.

"Ken's right," she said softly. "He says you can't get conceited. You're not satisfied with yourself even now, are you?" She smiled, rather gravely. Then she said, "But what I like is that you aren't really smart. A woman can make you do things. I have!"

He looked at her uneasily. She grinned.

"I, even I, can at least pretend to myself that I help bring this about! If I hadn't said please change the facts that are so annoying, and if I hadn't said you were big and strong and clever--I'm going to tell myself for the rest of my life that I helped make you do it!"

Massy swallowed.

"I'm afraid," he said miserably, "that it won't work again."

She cocked her head on one side.

"No?"

He stared at her apprehensively. And then with a bewildering change of emotional reaction, he saw that her eyes were filled with tears. She stamped her foot.

"You're ... horrible!" she cried. "Here I come in, and ... and if you think you can get me kidnaped to safety ... without even telling me that you 'rather like' me, like you told my brother, or that 'I'm pretty wonderful'--If you think."

He was stunned, that she knew. She stamped her foot again.

"For Heaven's sake!" she wailed. "Do I have to _ask_ you to kiss me?"

IV

During the last night of preparation, Massy sat by a thermometer registering the outside temperature. He hovered over it as one might over a sick child. He watched it and sweated, though the inside temperature of the drone-hull was lowered to save power. There was nothing he could actually do. At midnight the thermometer said it was seventy degrees below zero Fahrenheit. At halfway to dawn it was eighty degrees below zero Fahrenheit. The hour before dawn it was eighty-five degrees below zero. Then he sweated profusely. The meaning of the slowed descent was that carbon dioxide was being frozen out of the upper layers of the atmosphere. The frozen particles were drifting slowly downward, and as they reached lower and faintly warmer levels they returned to the state of gas. But there was a level, above the CO_{2}, where the temperature was plummeting.

The height to which carbon dioxide existed was dropping--slowly, but inexorably. And above the carbon-dioxide level there was no bottom limit to the temperature. The greenhouse effect was due to CO_{2}. Where it wasn't, the cold of space moved down. If at ground-level the thermometer read ever so slightly lower than one hundred and nine below zero--why--everything was finished. Without the greenhouse effect, the night-side of the planet would lose its remaining heat with a rush. Even the day-side, once cold enough, would lose heat to emptiness as fast as it came from the sun. Minus one hundred and nine point three was the critical reading. If it went down to that, it would plunge to a hundred and fifty--two hundred degrees below zero! And it would never come up again.

There would be rain at nightfall--a rain of oxygen frozen to a liquid and splashing on the ground. Human life would be quite simply impossible, in any shelter and under any conditions. Even spacesuits would not protect against an atmosphere sucking heat from it at that rate. A spacesuit can be heated against the loss of temperature due to radiation in a vacuum. It could not be heated against nitrogen which would chill it irresistibly by contact.

But, as Massy sweated over it, the thermometer steadied at minus eighty-five degrees. When the dawn came, it rose to seventy. By mid-morning, the temperature in bright sunshine was no lower than sixty-five degrees below zero.

But there was no bounce left in Massy when Herndon came for him.

"Your phone-plate's been flashing," said Herndon, "and you didn't answer. Must have had your back to it. Riki's over in the mine, watching them get things ready. She was worried that she couldn't call you. Asked me to find out what was the trouble."

Massy said heavily:

"Has she got something to heat the air she breathes?"

"Naturally," said Herndon. He added curiously, "What's the matter?"

"We almost took our licking," Massy told him. "I'm afraid for tonight, and tomorrow night, too. If the CO_{2} freezes--"

"We'll have power!" Herndon insisted. "We'll build ice tunnels and ice domes. We'll build a city under ice, if we have to. But we'll have power. We'll be all right!"

"I doubt it very much," said Massy. "I wish you hadn't told Riki of the bargain to get her away from here when the Survey ship comes!"

Herndon grinned.

"Is the little grid ready?" asked Massy.

"Everything's set," said Herndon exuberantly. "It's in the mine-tunnel with radiant heaters playing on it. The bombs are ready. We made enough to last for months, while we were at it. No use taking chances!"

Massy looked at him queerly. Then he said:

"We might as well go out and try the thing, then."

* * * * *

But he was very tired. He was not elated. _Riki can't be gotten away_, he thought wearily, _and I'm not going to go because it isn't quite fitting to go and leave her. They'll all be rejoicing presently, but nothing's settled._ Then he thought with exquisite irony, _She thinks I was inspired to genius by her, when I haven't done a thing I wasn't taught or didn't get out of books!_

He put on the cold-garments as they were now modified for the increased frigidity. Nobody could breathe air at minus sixty-five degrees without getting his lungs frost-bitten. So there was now a plastic mask to cover one's face, and the air one breathed outdoors was heated as it came through a wire-gauze snout. But still it was not wise to stay out of shelter for too long a time.

Massy went out-of-doors. He stepped out of the cold-lock and gazed about him. The sun seemed markedly paler, and now it had lost its sun-dogs again. Ice crystals no longer floated in the almost congealed air. The sky was dark. It was almost purple, and it seemed to Massy that he could detect faint flecks of light in it. They would be stars, shining in the daytime.

There seemed to be no one about at all, only the white coldness of the mountains. But there was a movement at the mine-drift, and something came out of it. Four men appeared, muffled up like Massy himself. They rolled the eighteen-foot grid out of the mine-mouth, moving it on those inflated bags which are so much better than rollers for rough terrain. They looked absurdly like bears with steaming noses, in their masks and clothing. They had some sort of powered pusher with them, and they got the metal cage to the very top of a singularly rounded stone upcrop which rose in the center of the valley.

"We picked that spot," said Herndon's muffled voice through the chill, "because by shifting the grid's position it can be aimed, and be on a solid base. Right?"

"Quite all right," said Massy. "We'll go work it."

He moved heavily across the valley, in which nothing moved except the padded figures of the four technicians. Their wire-gauze breathing-masks seemed to emit smoke. They waved to him in greeting.

_I'm popular again_, he thought drearily, _but it doesn't matter. Getting the Survey ship to ground won't help now, since Riki's forewarned. And this trick won't solve anything permanently on the home planet. It'll just postpone things._

He had a very peculiar ache inside. A Survey officer is naturally lonely. Massy had been lonely before he even entered the Service. He hadn't had a feeling of belonging anywhere, or with anyone, and no planet was really his home. Now he could believe that he belonged with someone. But there was the slight matter of a drop in the solar constant of an unimportant sol-type sun, and nothing could come of it.

Even when Riki--muffled like the rest--waved to him from the mouth of the tunnel, his spirits did not lift. The thing he wanted was to look forward to years and years of being with Riki. He wanted, in fact, to look forward to forever. And there might not be a tomorrow.

"I had the control board rolled out here," she called breathlessly through her mask. "It's cold, but you can watch!"

It wouldn't be much to watch. If everything went all right, some dial-needles would kick over violently, and their readings would go up and up. But they wouldn't be readings of temperature. Presently the big grid would report increased power from the sky. But tonight the temperature would drop a little farther. Tomorrow night it would drop farther still. When it reached one hundred and nine point three degrees below zero at ground-level--why it would keep on falling indefinitely. Then it wouldn't matter how much power could be drawn from the sky. The colony would die.

* * * * *

One of the figures that looked like a bear now went out of the mine-mouth, trudging toward the grid. It carried a muffled, well-wrapped object in its arms. It stooped and crept between the spokes of the grid. It put the object on the stone. Massy traced cables with his eyes. From the grid to the control board. From the board back to the reserve-power storage cells, deep in the mountain.

"The grid's tuned to the bomb," said Riki breathlessly, close beside him. "I checked that myself!"

The bearlike figure out in the valley jerked at the bomb. There was a small rising cloud of grayish vapor. It continued. The figure climbed hastily out of the grid. When the man was clear, Massy threw a switch.