There was a short message from Hilton pinned prominently on the wall. It said simply: “Went outside at 6.30. Will be gone about an hour. We’ll be hungry when we get back. Fred.”

  The hint could hardly be ignored. Besides, Gibson felt hungry himself. He rummaged through the emergency food pack which the aircraft carried for such accidents, wondering as he did so just how long it would have to last them. His attempts to brew a hot drink in the tiny pressure-boiler aroused Jimmy, who looked somewhat sheepish when he realized he was the last to wake.

  “Had a good sleep?” asked Gibson, as he searched round for the cups.

  “Awful,” said Jimmy, running his hands through his hair. “I feel I haven’t slept for a week. Where are the others?”

  His question was promptly answered by the sounds of someone entering the airlock. A moment later Hilton appeared, followed by the pilot. They divested themselves of masks and heating equipment— it was still around freezing point outside— and advanced eagerly on the pieces of chocolate and compressed meat which Gibson had portioned out with impeccable fairness.

  “Well,” said Gibson anxiously, “what’s the verdict?”

  “I can tell you one thing right away,” said Hilton between mouthfuls. “We’re damn lucky to be alive.”

  “I know that.”

  “You don’t know the half of it— you haven’t seen just where we landed. We came down parallel to this cliff for almost a kilometer before we stopped. If we’d swerved a couple of degrees to starboard— bang! When we touched down we did swing inwards a bit, but not enough to do any damage.

  “We’re in a long valley, running east and west. It looks like a geological fault rather than an old river bed, though that was my first guess. The cliff opposite us is a good hundred meters high, and practically vertical— in fact, it’s got a bit of overhang near the top. Maybe it can be climbed farther along, but we didn’t try. There’s no need to, anyway— if we want Phobos to see us we’ve only got to walk a little way to the north, until the cliff doesn’t block the view. In fact, I think that may be the answer— if we can push this ship out into the open. It’ll mean we can use the radio, and will give the telescopes and air search a better chance of spotting us.”

  “How much does this thing weigh?” said Gibson doubtfully.

  “About thirty tons with full load. There’s a lot of stuff we can take out, of course.”

  “No there isn’t!” said the pilot. “That would mean letting down our pressure, and we can’t afford to waste air.”

  “Oh Lord, I’d forgotten that. Still, the ground’s fairly smooth and the undercart’s perfectly O.K.”

  Gibson made noises indicating extreme doubt. Even under a third of Earth’s gravity, moving the aircraft was not going to be an easy proposition.

  For the next few minutes his attention was diverted to the coffee, which he had tried to pour out before it had cooled sufficiently.

  Releasing the pressure on the boiler immediately filled the room with steam, so that for a moment it looked as if everyone was going to inhale their liquid refreshment. Making hot drinks on Mars was always a nuisance, since water under normal pressure boiled at around sixty degrees Centigrade, and cooks who forgot this elementary fact usually met with disaster.

  The dull but nourishing meal was finished in silence, as the castaways pondered their pet plans for rescue. They were not really worried; they knew that an intensive search would now be in progress, and it could only be a matter of time before they were located. But that time could be reduced to a few hours if they could get some kind of signal to Phobos.

  After breakfast they tried to move the ship. By dint of much pushing and pulling they managed to shift it a good five meters. Then the caterpillar tracks sank into soft ground, and as far as their combined efforts were concerned the machine might have been completely bogged. They retired, panting, into the cabin to discuss the next move.

  “Have we anything white which we could spread out over a large area?” asked Gibson.

  This excellent idea came to nothing when an intensive search of the cabin revealed six handkerchiefs and a few pieces of grimy rag. It was agreed that, even under the most favorable conditions, these would not be visible from Phobos.

  “There’s only one thing for it,” said Hilton. “We’ll have to rip out the landing lights, run them out on a cable until they’re clear of the cliff, and aim them at Phobos. I didn’t want to do this if it could be avoided; it might make a mess of the wing and it’s a pity to break up a good aeroplane.”

  By his glum expression, it was obvious that the pilot agreed with these sentiments.

  Jimmy was suddenly struck with an idea.

  “Why not fix up a heliograph?” he asked. “If we flashed a mirror on Phobos they ought to be able to see that.”

  “Across six thousand kilometers?” said Gibson doubtfully.

  “Why not? They’ve got telescopes that magnify more than a thousand up there. Couldn’t you see a mirror flashing in the sun if it was only six kilometers away?”

  “I’m sure there’s something wrong with that calculation, though I don’t know what,” said Gibson. “Things never work out as simply as that. But I agree with the general idea. Now who’s got a mirror?”

  After a quarter hour’s search, Jimmy’s scheme had to be abandoned. There simply was no such thing as a mirror on the ship.

  “We could cut out a piece of the wing and polish that up,” said Hilton thoughtfully. “That would be almost as good.”

  “This magnesium alloy won’t take much of a polish,” said the pilot, still determined to defend his machine to the last.

  Gibson suddenly shot to his feet.

  “Will someone kick me three times round the cabin?” he announced to the assembly.

  “With pleasure,” grinned Hilton, “but tell us why.”

  Without answering, Gibson went to the rear of the ship and began rummaging among his luggage, keeping his back to the interested spectators. It took him only a moment to find what he wanted; then he swung quickly round.

  “Here’s the answer,” he said triumphantly.

  A flash of intolerable light suddenly filled the cabin, flooding every corner with a harsh brilliance and throwing distorted shadows on the wall. It was as if lightning had struck the ship, and for several minutes everyone was half-blinded, still carrying on their retinas a frozen picture of the cabin as seen in that moment of searing incandescence.

  “I’m sorry,” said Gibson contritely. “I’ve never used it at full power indoors before— that was intended for night work in the open.”

  “Phew!” said Hilton, rubbing his eyes. “I thought you’d let off an atomic bomb. Must you scare everyone to death when you photograph them?”

  “It’s only like this for normal indoor use,” said Gibson, demonstrating. Everyone flinched again, but this time the flash seemed scarcely noticeable. “It’s a special job I had made for me before I left Earth. I wanted to be quite sure I could do color photography at night if I wanted to. So far I haven’t had a real chance of using it.”

  “Let’s have a look at the thing,” said Hilton.

  Gibson handed over the flash-gun and explained its operation.

  “It’s built round a super-capacity condenser. There’s enough for about a hundred flashes on one charge, and it’s practically full.”

  “A hundred of the high-powered flashes?”

  “Yes; it’ll do a couple of thousand of the normal ones.”

  “Then there’s enough electrical energy to make a good bomb in that condenser. I hope it doesn’t spring a leak.”

  Hilton was examining the little gas-discharge tube, only the size of a marble, at the center of the small reflector.

  “Can we focus this thing to get a good beam?” he asked.

  “There’s a catch behind the reflector— that’s the idea. It’s rather a broad beam, but it’ll help.”

  Hilton looked very pleased.

  “They ought to see this
thing on Phobos, even in broad daylight, if they’re watching this part with a good telescope. We mustn’t waste flashes, though.”

  “Phobos is well up now, isn’t it?” asked Gibson. “I’m going out to have a shot right away.”

  He got to his feet and began to adjust his breathing equipment.

  “Don’t use more than ten flashes,” warned Hilton. “We want to save them for night. And stand in any shadow you can find.”

  “Can I go out too?” asked Jimmy.

  “All right,” said Hilton. “But keep together and don’t go wandering off to explore. I’m going to stay here and see if there’s anything we can do with the landing lights.”

  The fact that they now had a definite plan of action had raised their spirits considerably. Clutching his camera and the precious flash-gun close to his chest, Gibson bounded across the valley like a young gazelle. It was a curious fact that on Mars one quickly adjusted one’s muscular efforts to the lower gravity, and so normally used strides no greater than on Earth. But the reserve of power was available, when necessity or high spirits demanded it.

  They soon left the shadow of the cliff, and had a clear view of the open sky. Phobos was already high in the west, a little half-moon which would rapidly narrow to a thin crescent as it raced towards the south. Gibson regarded it thoughtfully, wondering if at this very moment someone might be watching this part of Mars. It seemed highly probable, for the approximate position of their crash would be known. He felt an irrational impulse to dance around and wave his arms— even to shout: “Here we are— can’t you see us?”

  What would this region look like in the telescopes which were, he hoped, now sweeping Aetheria? They would show the mottled green of the vegetation through which he was trudging, and the great cliff would be clearly visible as a red band casting a broad shadow over the valley when the sun was low. There would be scarcely any shadow now, for it was only a few hours from noon. The best thing to do, Gibson decided, was to get in the middle of the darkest area of vegetation he could find.

  About a kilometer from the crashed ship the ground sloped down slightly, and here, in the lowest part of the valley, was a wide brownish belt which seemed to be covered with tall weeds. Gibson headed for this, Jimmy following close behind.

  They found themselves among slender, leathery plants of a type they had never seen before. The leaves rose vertically out of the ground in long, thin streamers, and were covered with numberless pods which looked as if they might contain seeds. The flat sides were all turned towards the Sun, and Gibson was interested to note that while the sunlit sides of the leaves were black, the shadowed parts were a grayish white. It was a simple but effective trick to reduce loss of heat.

  Without wasting time to botanize, Gibson pushed his way into the center of the little forest. The plants were not crowded too closely together, and it was fairly easy to force a passage through them. When he had gone far enough he raised his flash-gun and squinted along it at Phobos.

  The satellite was now a thin crescent not far from the Sun, and Gibson felt extremely foolish aiming his flash into the full glare of the summer sky. But the time was really well chosen, for it would be dark on the side of Phobos towards them and the telescopes there would be observing under favorable conditions.

  He let off his ten shots in five pairs, spaced well apart. This seemed the most economical way of doing it while still making sure that the signals would look obviously artificial.

  “That’ll do for today,” said Gibson. “We’ll save the rest of our ammunition until after dark. Now let’s have a look at these plants. Do you know what they remind me of?”

  “Overgrown seaweed,” replied Jimmy promptly.

  “Right first time. I wonder what’s in those pods? Have you got a knife on you— thanks.”

  Gibson began carving at the nearest frond until he had punctured one of the little black balloons. It apparently held gas, and under considerable pressure, for a faint hiss could be heard as the knife penetrated.

  “What queer stuff!” said Gibson. “Let’s take some back with us.”

  Not without difficulty, he hacked off one of the long black fronds near the roots. A dark brown fluid began to ooze out of the severed end, releasing tiny bubbles of gas as it did so. With this souvenir hanging over his shoulder, Gibson began to make his way back to the ship.

  He did not know that he was carrying with him the future of a world.

  They had gone only a few paces when they encountered a denser patch and had to make a detour. With the sun as a guide there was no danger of becoming lost, especially in such a small region, and they had made no attempt to retrace their footsteps exactly. Gibson was leading the way, and finding it somewhat heavy going. He was just wondering whether to swallow his pride and change places with Jimmy when he was relieved to come across a narrow, winding track leading more or less in the right direction.

  To any observer, it would have been an interesting demonstration of the slowness of some mental processes. For both Gibson and Jimmy had walked a good six paces before they remembered the simple but shattering truth that footpaths do not, usually, make themselves.

  “It’s about time our two explorers came back, isn’t it?” said the pilot as he helped Hilton detach the floodlights from the underside of the aircraft’s wing. This had proved, after all, to be a fairly straight-forward job, and Hilton hoped to find enough wiring inside the machine to run the lights far enough away from the cliff to be visible from Phobos when it rose again. They would not have the brilliance of Gibson’s flash, but their steady beams would give them a better chance of being detected.

  “How long have they been gone now?” said Hilton.

  “About forty minutes. I hope they’ve had the sense not to get lost.”

  “Gibson’s too careful to go wandering off. I wouldn’t trust young Jimmy by himself, though— he’d want to start looking for Martians!”

  “Oh, here they are. They seem to be in a bit of a hurry.”

  Two tiny figures had emerged from the middle distance and were bounding across the valley. Their haste was so obvious that the watchers downed tools and observed their approach with rising curiosity.

  The fact that Gibson and Jimmy had returned so promptly represented a triumph of caution and self-control. For a long moment of incredulous astonishment they had stood staring at that pathway through the thin brown plants. On Earth, nothing could have been more commonplace; it was just the sort of track that cattle make across a hill, or wild animals through a forest. Its very familiarity had at first prevented them from noticing it, and even when they had forced their minds to accept its presence, they still kept trying to explain it away.

  Gibson had spoken first, in a very subdued voice— almost as if he was afraid of being overheard.

  “It’s a path all right, Jimmy. But what could have made it, for heaven’s sake? No one’s ever been here before.”

  “It must have been some kind of animal.”

  “A fairly large one, too.”

  “Perhaps as big as a horse.”

  “Or a tiger.”

  The last remark produced an uneasy silence. Then Jimmy said: “Well, if it comes to a fight, that flash of yours should scare anything.”

  “Only if it had eyes,” said Gibson. “Suppose it had some other sense?”

  It was obvious that Jimmy was trying to think of good reasons for pressing ahead.

  “I’m sure we could run faster, and jump higher, than anything else on Mars.”

  Gibson liked to believe that his decision was based on prudence rather than cowardice.

  “We’re not taking any risks,” he said firmly. “We’re going straight back to tell the others. Then we’ll think about having a look round.”

  Jimmy had sense enough not to grumble, but he kept looking back wistfully as they returned to the ship. Whatever faults he might have, lack of courage was not among them.

  It took some time to convince the others that they were not attempting
a rather poor practical joke. After all, everyone knew why there couldn’t be animal life on Mars. It was a question of metabolism: animals burned fuel so much faster than plants, and therefore could not exist in this thin, practically inert atmosphere. The biologists had been quick to point this out as soon as conditions on the surface of Mars had been accurately determined, and for the last ten years the question of animal life on the planet had been regarded as settled— except by incurable romantics.

  “Even if you saw what you think,” said Hilton, “there must be some natural explanation.”

  “Come and see for yourself,” retorted Gibson. “I tell you it was a well-worn track.”

  “Oh, I’m coming,” said Hilton.

  “So am I,” said the pilot.

  “Wait a minute! We can’t all go. At least one of us has got to stay behind.”

  For a moment Gibson felt like volunteering. Then he realized that he would never forgive himself if he did.

  “I found the track,” he said firmly.

  “Looks as if I’ve got a mutiny on my hands,” remarked Hilton. “Anyone got some money? Odd man out of you three stays behind.”

  “It’s a wild goose chase, anyway,” said the pilot, when he produced the only head. “I’ll expect you home in an hour. If you take any longer I’ll want you to bring back a genuine Martian princess, à la Edgar Rice Burroughs.”

  Hilton, despite his skepticism, was taking the matter more seriously.

  “There’ll be three of us,” he said, “so it should be all right even if we do meet anything unfriendly. But just in case none of us come back, you’re to sit right here and not go looking for us. Understand?”

  “Very well. I’ll sit tight.”

  The trio set off across the valley towards the little forest, Gibson leading the way. After reaching the tall thin fronds of “seaweed,” they had no difficulty in finding the track again. Hilton stared at it in silence for a good minute, while Gibson and Jimmy regarded him with “I told you so” expressions. Then he remarked: “Let’s have your flash-gun, Martin. I’m going first.”