It was hard not to feel some sympathy for the director; Sad­ler suspected that he was on the verge of a nervous breakdown, and would have to be handled with extreme care.

  "What do you want me to do about it?" he asked in as non­committal a tone of voice as he could manage.

  "I'd like to know if you agree with me about Jamieson. You must have studied him carefully."

  "I'm not allowed to discuss my evaluations," Sadler replied. "They're too often based on hearsay and hunches. But I feel that jamieson's very frankness is a point in his favor. There is a great difference, you know, between dissent and treason."

  Maclaurin was silent for a while. Then he shook his head angrily.

  "It's too great a risk. I'll not accept the responsibility."

  This, thought Sadler, was going to be difficult. He had no authority here, and certainly could not override the director. No one had sent him any instructions; the people who had routed Steffanson through the Observatory probably did not even know that he existed. Liaison between Defense and Cen­tral Intelligence was not all that it should be.

  But even without instructions, his duty was clear. If De­fense wanted to get someone out to Project Thor as urgently as this, they had a very good reason. He must help even if he had to step outside his role of passive observer.

  "This is what I suggest, sir," he said briskly. "Interview Jamieson and outline the position to him. Ask him if he'll volunteer for the job. I'll monitor the conversation from the next room and advise you if it's safe to accept. My belief is that

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  if he says he'll do it, he will. Otherwise he'll turn you down flat. I don't think he'll double-cross you."

  "You'll go on record over this?"

  "Yes," said Sadler, impatiently. "And if I may give some advice, do your best to hide your suspicions. Whatever your own feelings are, be as friendly and open as you can."

  Maclaurin thought it over for a while, then shrugged his shoulders in resignation. He flicked the microphone switch.

  "Wagnall," he said, "fetch Jamieson here."

  To Sadler, waiting in the next room, it seemed hours before anything happened. Then the loudspeaker brought the sound of Jamieson's arrival, and immediately he heard Maclaurin say:

  "Sorry to break into your sleep, Jamieson, but we've an urgent job for you. How long would it take you to drive a tractor to Prospect Pass?"

  Sadler smiled at the clearly heard gasp of incredulity. He knew exactly what Jamieson was thinking. Prospect was the pass through the southern wall of Plato, overlooking the Mare Itnbrium. It was avoided by the tractors, which took an easier but more roundabout route a few kilometers to the west. The monocabs, however, went through it without difficulty, and when the lighting was correct gave their passengers one of the most famous views on the Moon—the great sweep down into the Mare with the far-off fang of Pico on the skyline.

  "If I pushed things, I could do it in an hour. It's only forty kilometers, but very rough going."

  "Good," said Maclaurin's voice. "I've just had a message from Central City, asking me to send you out. They know you're our best driver, and you've been there before."

  "Been where?" said Jamieson.

  "Project Thor. You won't have heard the name, but that's what it's called. The place you drove out to the other night."

  "Go on, sir. I'm listening," Jamieson replied. To Sadler, the tension in his voice was obvious.

  "This is the position. There's a man in Central City who has to reach Thor immediately. He was supposed to go by rocket, but that's not possible. So they're sending him down here on the monorail, and to save time you'll meet the car out in the pass and

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  take him off. Then you'll drive straight across country to Project Thor. Understand?"

  "Not quite. Why can't Thor collect him in one of their own Cats?"

  Was Jamieson hedging? wondered Sadler. No, he decided. It was a perfectly reasonable question.

  "If you look at the map," said Maclaurin, "you'll see that Prospect is the only convenient place for a tractor to meet the monorail. Moreover, there aren't any really skilled drivers at Thor, it seems. They're sending out a tractor, but you'll probably have finished the job before they can reach Prospect."

  There was a long pause. Jamieson was obviously studying the map.

  "I'm willing to try it," said Jamieson. "But I'd like to know what it's all about."

  Here we go, thought Sadler. I hope Maclaurin does what I told him.

  "Very well," Maclaurin replied. "You've a right to know, I suppose. The man who's going to Thor is Dr. Carl Steffanson. And the mission he's engaged on is vital to the security of Earth. That's all I know, but I don't think I need say any more."

  Sadler waited, hunched over his speaker, as the long silence dragged on. He knew the decision Jamieson must be making. The young astronomer was discovering that it was one thing to criticize Earth and to condemn her policy when the matter was of no practical importance—and quite another to choose a line of action that might help to bring about her defeat. Sadler had read somewhere that there were plenty of pacifists before the outbreak of war, but few after it had actually started. Jamieson was learning now where his loyalty, if not his logic, lay.

  "I'll go," he said at last, so quietly that Sadler could scarcely hear him.

  "Remember," insisted Maclaurin, "you have a free choke."

  "Have I?" said Jamieson. There was no sarcasm in his voice. He was thinking aloud, talking to himself rather than to the director.

  Sadler heard Maclaurin shuffling his papers. "What about your co-driver?" he asked.

  "I'll take Wheeler. He went out with me last time."

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  "Very well. You go and fetch him, and I'll get in touch with Transport. And—good luck."

  "Thank you, sir."

  Sadler waited until he heard the door of Maclaurin's office dose behind Jamieson; then he joined the director. Maclaurin looked up at him wearily and said:

  "Well?"

  "It went off better than I'd feared. I thought you handled it very well."

  This was not mere flattery; Sadler was surprised at the way in which Maclaurin had concealed his feelings. Though the in­terview had not been exactly cordial, there had been no overt unfriendliness.

  "I feel much happier," said Maclaurin, "because Wheeler's going with him. He can be trusted."

  Despite his worry, Sadler had difficulty in suppressing a smile. He was quite sure that the director's faith in Conrad Wheeler was based largely on that young man's discovery of Nova Dra-conis and his vindication of the Maclaurin Magnitude Inte­grator. But he needed no further proofs that scientists were just as inclined as anyone else to let their emotions sway their logic.

  The desk speaker called for attention.

  "The tractor's just leaving, sir. Outer doors opening now."

  Maclaurin looked automatically at the wall clock. "That was quick," he said. Then he gazed somberly at Sadler.

  "Well, Mr. Sadler, it's too late to do anything about it now. I only hope you're right."

  It is seldom realized that driving on the Moon by day is far less pleasant, and even less safe, than driving by night. The mer­ciless glare demands the use of heavy sun filters, and the pools of inky shadow which are always present except on those rare occasions when the sun is vertically overhead can be very dan­gerous. Often they conceal crevasses which a speeding tractor may be unable to avoid. Driving by Earthlight, on the other hand, involves no such strain. The light is so much softer, the contrasts less extreme.

  To make matters worse for Jamieson, he was driving due south—almost directly into the sun. There were times when

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  conditions were so bad that he had to zigzag wildly to avoid the glare from patches of exposed rock ahead. It was not so difficult when they were traveling over dusty regiore, but these became fewer and fewer as the ground rose toward the inner ramparts of the mountain wall.

  Wheeler knew better than to ta
lk to his friend on this part of the route: Jamieson's task required too much concentration. Presently they were climbing up toward the pass, weaving back and forth along the rugged slopes overlooking the plain. Like fragile tops on the far horizon, the gantries of the great tele­scopes marked the location of the Observatory. There, thought Wheeler bitterly, was invested millions of man-hours of skill and labor. Now it was doing nothing, and the best that could be hoped was that one day those splendid instruments could once more begin their search into the far places of the universe.

  A ridge cut off their view of the plain below, and Jamieson swung round to the right through a narrow valley. Far up the slopes above them, the track of the monorail was now visible, as it came in great, striding leaps down the face of the moun­tain. There was no way in which a Caterpillar could get up to it, but when they were through the pass they would have no diffi­culty in driving to within a few meters of the track.

  The ground was extremely broken and treacherous here, but drivers who had gone this way before had left markers for the guidance of any who might come after them. Jamieson was using his headlights a good deal now, as he was often working through shadow. On the whole he preferred this to direct sunlight, for he could see the ground ahead much more easily with the steer-able beams from the projectors on top of the cab. Wheeler soon took over their operation, and found it fascinating to watch the ovals of light skittering across the rocks. The complete invisi­bility of the beams themselves, here in the almost perfect vacuum, gave a magical effect to the scene. The light seemed to be coming from nowhere, and to have no connection at all with the tractor.

  They reached Prospect fifty minutes after leaving the Observa­tory, and radioed back their position. From now on, it was only a few kilometers downhill until they came to the rendezvous. The monorail track converged toward their path, then swept on

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  to the south past Pico, a silver thread shrinking out of sight across the face of the Moon.

  "Well," said Wheeler with satisfaction, "we haven't kept them waiting. I wish I knew what all this is about."

  "Isn't it obvious?" Jamieson answered. "Steffanson's the greatest expert on radiation physics we have. If there's going to be war, surely you realize the sort of weapons that will be used."

  "I hadn't thought much about it—it never seemed something to take seriously. Guided missiles, I suppose."

  "Very likely, but we should be able to do better than that. Men have been talking about radiation weapons for centuries. If they wanted them, they could make them now."

  "Don't say you believe in death-rays!"

  "And why not? If you remember your history books, death-rays killed some thousands of people at Hiroshima. And that was a couple of hundred years ago.

  "Yes, but it's not difficult to shield against that sort of thing. Can you imagine doing any real physical damage with a ray?"

  "It would depend on the range. If it was only a few kilome­ters, I'd say yes. After all, we can generate unlimited amounts of power. By this time we should be able to squirt it all in the same direction if we wanted to. Until today there's been no particular incentive. But now—how do we know what's been going on in secret labs all over the solar system?"

  Before Wheeler could reply, he saw the glittering point of light far out across the plain. It was moving toward them with incredible speed, coming up over the horizon like a meteor. Within minutes, it had resolved itself into the blunt-nosed cylin­der of the monocab, crouched low over its single track.

  "I think I'd better go out and give him a hand," said Jamie-son. "He's probably never worn a spacesuit before. He'll certain­ly have some luggage, too."

  Wheeler sat up in the driving position and watched his friend clamber across the rocks to the monorail. The door of the ve­hicle's emergency airlock opened, and a man stepped out, some­what unsteadily, onto the Moon. By the way he moved, Wheeler could tell at a glance that he had never been in low gravity be­fore.

  Steffanson was carrying a thick briefcase and a large wooden

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  box, which he handled with the utmost care. Jamieson offered to relieve him of these hindrances, but he refused to part with them. His only other baggage was a small traveling-case, which he allowed Jamieson to carry.

  The two figures scrambled back down the rocky ramp and Wheeler operated the airlock to let them in. The monocab hav­ing delivered its burden, pulled back into the south and swiftly disappeared the way it had come. It seemed, thought Wheeler, that the driver was in a great hurry to get home. He had never seen one of the cars travel so fast, and for the first time he began to have some faint surmise of the storm that was gathering above this peaceful, sun-drenched landscape. He suspected that they were not the only ones making a rendezvous at Project Thor.

  He was right. Far out in space, high above the plane in which Earth and planets swim, the commander of the Federal forces was marshaling his tiny fleet. As a hawk circles above its prey in the moments before its plumeting descent, so Commodore Brennan, lately Professor of Electrical Engineering at the Uni­versity of Hesperus, held his ships poised above the Moon.

  He was waiting for the signal which he still hoped would never come.

  Chapter XV

  doctor carl steffanson did not stop to wonder if he was a brave man. Never before in his life had he known the need for so primitive a virtue as physical courage, and he was agreeably surprised at his calmness now that the crisis had almost come. In a few hours, he would probably be dead. The thought gave him more annoyance than fear; there was so much work he wanted to do, so many theories to be tested. It would be won­derful to get back to scientific research again, after the rat-race of the last two years. But that was day-dreaming; mere survival was as much as he could hope for now.

  He opened his briefcase and pulled out the sheafs of wiring diagrams and component schedules. With some amusement, he

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  noticed that Wheeler was staring with frank curiosity at the complex circuits and the SECRET labels plastered over them. Well, there was little need for security now, and Steffanson himself could not have made much sense of these circuits had he not invented them himself.

  He glanced again at the packing case to make sure that it was securely lashed down. There, in all probability, lay the future of more worlds than one. How many other men had ever been sent on a mission like this? Steffanson could think of but two examples, both back in the days of the Second World War. There had been a British scientist who had carried a small box across the Atlantic, containing what was later called the most valuable consignment ever to reach the shores of the United States. That had been the first cavity magnetron, the invention which made radar the key weapon of war and destroyed the power of Hitler. Then, a few years later, there had been a plane flying across the Pacific to the island of Tinian, carrying almost all the free uranium 235 then in existence. . . .

  But neither of those missions, for all their importance, had the urgency of this.

  Steffanson had exchanged only a few words of formal greet­ing with Jamieson and Wheeler, expressing his thanks at their cooperation. He knew nothing about them, except that they were astronomers from the Observatory who had volunteered to un­dertake this trip. Since they were scientists, they would certainly be curious to know what he was doing here, and he was not surprised when Jamieson handed over the controls to his col­league and stepped down from the driving position.

  "It won't be so rough from now on," said Jamieson. "We'll get to this Thor place in about twenty minutes. Is that good enough for you?"

  Steffanson nodded.

  "That's better than we'd hoped, when that damn ship broke down. You'll probably get a special medal for this."

  "I'm not interested," said Jamieson rather coldly. "All I want to do is what's right. Are you quite certain that you're doing the same?"

  Steffanson looked at him in surprise, but it took him only an instant to sum up the situation. He had met Jamieson's type be-
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  fore among the younger men of his own staff. These idealists all went through the same mental heart-searchings. And they would all grow out of it when they were older. He sometimes wondered if that was a tragedy or a blessing.

  "You are asking me," he said quietly, "to predict the future. No man can ever tell if, in the long run, his acts wi' lead to good or evil. But I am working for the defense of Earth, and if there is an attack it will come from the Federation, not from us. I think you should bear that in mind."

  "Yet haven't we provoked it?"