"Well," Richard said at length, shrugging his shoulders, "here we go," He put his right foot on one of the spikes to test its ability to hold his weight. It was firm. He moved his left leg down to another of the spikes and descended one more level with his right leg. "The s.p.a.cing is nearly perfect," he said, glancing back at Nicole. "It shouldn't be a difficult climb."

"Richard Wakefield," Nicole said from the rim of the hole, "are you trying to tell me that you intend to climb down into that chasm? And that you expect me to follow?"

"I don't expect anything of you," he replied. "But I can't see turning back now. What's our alternative? Should we go back down the tunnel to the ramps and exit? For what? To see if anyone has found us yet? You saw the photographs of the boats. Maybe they're right here at the bottom. Maybe there's even a secret river that runs underground into the Cylindrical Sea." "Maybe," Nicole said, starting to descend slowly now that Richard's progress had triggered another bank of lights below them, "one of those things that made the bizarre noise is waiting for us down at the bottom."

"I'll find out," Richard said. "Hallooo, down there. We two human-type beings are coming down." He waved and momentarily lost his balance.

"Don't be a show-off," Nicole said, coming down beside him. She paused to catch her breath and look around. Her two feet were resting on spikes and she was holding tightly to two others with her hands. / must be insane, she said to herself, just look at this place. It's easy to imagine a hundred gruesome deaths. Richard had dropped down to another pair of spikes. And look at him. Is he totally immune to fear? Or just reckless? He actually seems to be enjoying all this.

The third bank of lights illuminated a lattice on the opposite wall below them. It was hanging among all the spikes and, from a distance in the dim light, looked startlingly like a smaller version of the object that had been attached to the two skysc.r.a.pers in New York. Richard hurried around the cylinder to examine the lattice. "Come over here," he shouted at Nicole. "I think it's the same d.a.m.n material." The lattice was anch.o.r.ed to the wall by small bolts. At Richard's insistence, Nicole cut off a piece and handed it to him. He stretched it and watched it regain its shape. He studied its internal structure. "It is the same stuff," he said. His brow knitted into furrows. "But what the h.e.l.l does it mean?"

Nicole stood beside him and idly shone her flashlight into the depths below them. She was about to suggest that they climb out and head for more familiar terrain when she thought she saw a reflection from a floor about twenty meters below. "I'm going to make you a proposition," Nicole said to Richard. "While you're studying that lattice cord, I'll drop down another several meters. We may be near the bottom of this bizarre well of spikes, or whatever it is. If not, then we'll abandon this place."

"All right," Richard said absentmindedly. He was already involved in his examination of the lattice cord using the microscope he had taken from his backpack.

Nicole nimbly descended to the floor. "I guess you'd better come down," she called to Richard. "There are two more tunnels, one large and one small. Plus another hole in the center-" He was beside her immediately. He had climbed down as soon as he had seen the lower platform illuminated by lights.

Richard and Nicole were now standing on a ledge three meters wide at the bottom of the spiked cylinder. The ledge formed a ring around another smaller descending hole that also had spikes growing out of its walls. To their left and right, dark arched tunnels were cut into the rock or metal that was the base construction material for the extensive underground world. The tunnel on their left was five to six meters high; the tiny tunnel on the opposite side, one hundred and eighty degrees around the ring, was only half a meter tall.

Running out of each of the two tunnels, and penetrating half a ledge-width into the ring, were two small parallel strips of unknown material that were fastened to the floor. The strips were very close together in the smaller tunnel and more widely s.p.a.ced in the other. Richard was sitting on his knees examining the strips in front of the large tunnel when he heard a distant rumble. "Listen," he said to Nicole, as the two of them instinctively backed away from the entrance. The rumbling increased and changed into a whining sound, as if something were moving swiftly through the air. Far off in the tunnel, which ran straight as an arrow, Richard and Nicole could see some lights switch on. They tensed. They didn't need to wait long for an explanation. A vehicle that resembled a hovering subway burst into view and sped toward them, stopping suddenly with its front edge just over the farthest extension of the strips on the floor. Richard and Nicole had recoiled as the vehicle had hurtled toward them. Both were dangerously close to the edge of the ring. For several seconds they stood in silence, each staring at the aerodynamic shape hovering in front of them. Then they looked at each other and laughed simultaneously.

"Okay," Nicole said nervously, "I get it. We've crossed into some new dimension. In this one it's just a little difficult to find the subway station. . . . This is so totally absurd. We climb down a spiked barrel and end up in a Metro station. ... I don't know about you, Richard, but I've had enough. I'll take a few normal avians and manna melon any day of the week. . . ."

Richard had walked over beside the vehicle. A door in the side had opened and they could both see the lit interior. There were no seats, only thin cylindrical poles, s.p.a.ced in no obvious pattern, that ran the three meters from the ceiling to the floor. "It can't go far," Richard said, sticking his head inside the door but leaving his feet on the ledge outside.

"There's no place to sit down/'

Nicole came over to inspect for herself. "Maybe they have no old or crippled people-and the grocery stores are all close to home." She laughed again as Richard leaned farther into the car so he could see the ceiling and walls more clearly.

"Don't get any crazy ideas," she said. "It would be certifiably insane for us to climb aboard that car. Unless we were out of food and it was our last hope."

"I guess you're right," Richard replied. He was definitely disappointed as he withdrew from the subway car. "But what an amazing-" He stopped himself in midsentence. He was staring across the platform at the opposite side of the ledge. There, in the middle of the now illuminated entrance to the tiny tunnel, an identical vehicle, one-tenth the size of the one next to them, was hovering off the floor. Nicole followed Richard's gaze.

"That must be the road to Lilliput over there" Nicole said.

"Giants descend another floor and normal-size creatures take this subway. It's all very simple."

Richard walked swiftly around the ring. "That's perfect," he said out loud, taking off his backpack and setting it on the ledge beside him. He began to rummage in one of the large pockets.

"What are you doing?" Nicole asked.

Richard pulled two tiny figures out of the pack and showed them to her. "It's perfect," he repeated, his excitement unmistakable. "We can send Prince Hal and Falstaff. I'll only need a few minutes to adjust their software." Already Richard had spread his pocket computer out on the ledge beside the robots and was busily working away. Nicole sat down with her back against the wall between two spikes. She glanced over at Richard. He is truly a rare species, she said with admiration, thinking back over their hours together. A genius, that's obvious. Almost without guile or meanness. And somehow he has retained the curiosity of a child.

Nicole suddenly felt very tired. She smiled to herself as she was watching Richard. He was absorbed in his work. Nicole closed her eyes for a moment.

"I'm sorry that I took so long," Richard was saying. "I kept thinking of new things to add and I needed to rearrange the linkage ..."

Nicole woke up from her nap very slowly. "How long have we been here?" she said as she yawned.

"A little over an hour/' Richard answered sheepishly. "But everything is all set. I'm ready to put the boys in the subway." Nicole glanced around her. "Both the cars are still here," she commented.

"I think they work like all the lights. I bet they will stay in the station as long as we're on the platform." Nicole stood up and stretched. "So here's the plan/' Richard said. "I have the controlling transceiver in my hand. Hal and Sir John each have audio, video, and infrared sensors that will acquire data continuously. We can choose which channel to monitor on our computers and send new commands as necessary."

"But will the signals penetrate the walls?" Nicole asked, remembering her experience inside the barn.

"As long as they don't have to travel through too much material. The system is way overdesigned in terms of signal to noise to accommodate some attenuation. . . . Besides, the large subway came at us along a straight line. I'm hoping this one will be similar."

Richard gingerly set the two robots down on the ledge and commanded them to walk toward the subway. Doors opened on both sides as they drew near. "Remember me to Mistress Quickly," Falstaff said as he climbed aboard. "She was a stupid la.s.s, but with a good heart."

Nicole gave Richard a puzzled glance. "I didn't overwrite all their earlier programming," he said with a laugh. "From time to time they will probably make some absurd random comments."

The two robots stood on the subway for a minute or two. Richard hastily checked their sensors and made one more set of calibrations on the monitor. At length the doors of the subway closed, the vehicle watted for another ten seconds, and then it rushed away into the tunnel.

Richard commanded Falstaff to face the front, but there was not much to be seen out the window. It was a surprisingly long ride at a very high speed. Richard estimated that the little subway had traveled more than a kilometer before it finally slowed to a stop.

Richard waited before commanding the two robots to leave the subway. He wanted to make certain that they did not get off at an intermediate stop. However, there was no need to worry: the first full set of imaging data from Prince Hal and Falstaff showed that the subway had indeed reached the end of the line.

The two robots walked around the flat platform beside the vehicle and photographed more of their surroundings. The subway station had arches and columns, but it was basically one long, connected room. Richard estimated from the images that the ceiling height was about two meters. He commanded Hal and Falstaff to follow a long hallway that moved off to the left, perpendicular to the subway track. The hallway terminated in front of another tunnel, this one barely five centimeters high. As the robots examined the Boor, finding two tiny strips extending almost to their feet, a subway of minuscule proportions arrived in the station. With its doors open and its interior lit, Richard and Nicole could see that the new subway car was identical, except for its size, to the two they had seen before.

The cosmonauts were sitting together with their knees on the ledge, both avidly watching the small computer monitor. Richard commanded Falstaff to take a picture of Prince Hal standing next to the tiny subway. "The car itself," Richard said to Nicole after studying the image, "is less than two centimeters tall. What's going to ride in it? Ants?" Nicole shook her head and said nothing. She was feeling bewildered again. At that moment she was also thinking about her initial reactions to Rama. Never in my wildest imagination, she thought, recalling her awe at that first panoramic sight, did I foresee that there would be so many new mysteries. The first explorers hardly scratched the surface"Richard," Nicole said, interrupting her own thoughts. He commanded the robots to walk back down the hallway and then glanced up from the monitor. 'Yes?" he said.

"How thick is the outer sh.e.l.l of Rama?"

"I think the ferry covers about four hundred meters altogether," he said with a slightly puzzled expression. "But that's at one of the ends. We have no definite way of knowing how thick the sh.e.l.l is anywhere else. Norton and crew reported that the depth of the Cylindrical Sea was highly variable-as little as forty meters in some places and as much as a hundred and fifty elsewhere. That would suggest to me a sh.e.l.l thickness of several hundred meters at least."

Richard checked the monitor quickly. Prince Hal and Falstaff were almost back at the station where they had climbed off the subway. He transmitted a stop command and turned to Nicole. "Why are you asking? It's not like you to ask idle questions."

"There's obviously an entire unexplored world down here," Nicole replied. "It would take a lifetime-"

"We don't have that long," Richard broke in with a laugh.

"At least not a normal lifetime. . . . But back to your thickness question, remember the entire Southern Hemicylinder has a floor level four hundred and fifty meters above the north. So unless there are some major structural irregularities-and we certainly haven't seen any from the outside-the thickness should be substantially greater in the south."

Richard waited for Nicole to say something additional. When she remained silent for several seconds, he turned back to the monitor and continued his surrogate exploration with the robots.

There had been a good reason for Nicole's question about the thickness of the sh.e.l.l. She had a picture in her mind that she could not shake. Nicole was imagining coming to the end of one of these long underground tunnels, opening a door, and then being blinded by the light of the Sun. Wouldn't it be incredible, she was thinking, to be an intelligent creature living in this maze of dim light and tunnels and then, by chance, to stumble onto something that would irrevocably change your entire concept of the Universe? How could you return"Now what in the world is that?" Richard was asking. Nicole stopped her mental drifting and focused on the monitor. Prince Hal and Falstaff had entered a large room at the opposite end of the subway station and were standing in front of a conglomeration of loose, spongelike webbing. The infrared image of the scene showed a nested sphere, inside the web, that was radiating heat. At Nicole's suggestion, Richard commanded the robots to walk around the object and survey the rest of this new domain.

The room was immense. It extended into the distance farther than the resolution of the video devices carried by the robots. The ceiling was about twenty meters high and the two side walls were separated by more than fifty meters. Several other similar spherical objects encased in spongy ma.s.ses could be seen scattered about the room in the distance. A lattice, stretching almost all the way across the room but stopping five meters above the floor, dangled from the high ceiling in the foreground. Another lattice could barely be discerned a hundred meters or so behind the first one.

Richard and Nicole discussed what the robots should do next. There were no other exits from either the subway station or the large room. A panoramic image around the room revealed nothing nearby of interest except the sphere embedded in its spongy exterior, Nicole wanted to bring the robots back and leave the lair altogether. Richard's curiosity demanded at least a cursory investigation of one of the spherical objects.

The two robots were able, with some difficulty, to climb around and through the webbed material to reach the sphere in the center. The ambient temperature increased as they neared the sphere. One of the purposes of the external material was clearly to absorb heat. When the robots reached the nested sphere, their internal monitors flashed a warning that the outside temperatures exceeded their safe operating limits.

Richard moved quickly. Directing the robots on a nearly continuous basis, he determined that the sphere was virtually impenetrable and was probably made of a thick metal alloy with a very hard surface. Falstaff banged on the sphere several times with his arm; the resulting sound damped quickly, indicating the sphere was full, possibly with a liquid. The two robots were weaving their way out of the sponge webbing when their audio systems picked up the sound of brushes dragging against metal.

Richard tried to speed up their escape. Hal was able to increase his pace but Falstaff, whose subsystem temperatures had risen too high during his proximity to the sphere, was prevented by his own internal processor logic from accelerating his actions. The brush sound continued to grow louder.

The computer monitor on the ledge between the two cosmonauts was changed to split screen. Prince Hal reached the edge of the sponge, hit the floor, and headed for the subway without waiting for his companion. Falstaff continued to climb slowly through the webbing. " Tis too much work for a drinking man," he mumbled, as he crawled over another barrier.

The dragging metal sound abruptly stopped and Falstaff's camera recorded an image of a long, skinny object with black and gold stripes. Moments later the camera frame went to all black and the little robot's "Terminal Fault Imminent" alarm began to sound. Richard and Nicole had one more fleeting glimpse of a picture from Falstaff; it showed what might have been a giant eye, from up close, a black gelatinous mixture tinged with blue. Then all transmissions from the robot, including emergency telemetry, abruptly ceased.

Meanwhile Hal had entered the waiting subway. During the several seconds before the subway left the station, the ominous dragging sound was heard again. But the subway departed anyway, with the robot inside, and started speeding through the tunnel toward the two cosmonauts. Richard and Nicole breathed a sigh of relief.

Not more than a second later a loud sound like breaking gla.s.s was picked up by Prince Hal's audio system. Richard commanded the robot to turn in the direction of the sound and Hal's camera photographed a solitary black and gold tentacle in midair. The tentacle had broken the window and was moving inexorably toward the robot. Both Richard and Nicole realized what was happening at the same moment. The thing was on top of the subway! And it was coming toward them!

Nicole was climbing the spikes in a flash. Richard wasted several valuable seconds picking up his computer monitor and putting all his equipment in the backpack. He heard Prince Hal's Terminal Fault Imminent alarm when he was halfway up the spikes. Richard turned around to look just as the subway pulled into the tunnel below him.

What he saw made his blood run cold. On top of the subway was a large dark creature whose central body, if that's indeed what it was, was flattened against the roof. Striped tentacles extended in all directions. Four of them had pierced the windows of the train and grabbed the robot. The thing quickly climbed off the subway and wrapped one of its eight tentacles around the lowest spikes. Richard didn't watch anymore. He clambered up the rest of the cylinder and started racing through the tunnel at the top, following the steps of Nicole far ahead of him in the distance. As he ran, Richard noticed that the tunnel was curving slightly to the right. He reminded himself that even though this was not the same tunnel they had used before, it should still lead them to the ramps. After several hundred meters Richard stopped to listen for the sound of his pursuer. He heard nothing. Richard had just taken two deep breaths and started to run again when his ears were a.s.saulted by a terrible wail in front of him. It was Nicole. Oh s.h.i.t, he thought, as he rushed forward to find her.

47 PROGRESSIVE MATRICES.

Never, never in my entire life," Nicole said to Richard, "have I ever seen anything that terrified me like that." The two cosmonauts were sitting with their backs against the bottom of one of the skysc.r.a.pers surrounding the western plaza. They were both still breathing heavily, exhausted from their frantic escape. Nicole took a long drink of water.

"I had just started to relax/' she continued. "I could hear you behind me -and nothing else. I decided I would stop in the museum and wait for you to catch up. It hadn't yet occurred to me that we were in the 'other' tunnel.

"It should have been obvious, of course, because the opening was on the wrong side. But I wasn't thinking logically at the moment. . . . Anyway, I stepped inside the room, the lights came on, and there he was, not more than three meters in front of me. I thought my heart had stopped altogether. . . ."

Richard remembered Nicole running into his arms in the tunnel and sobbing for several seconds. "It's Takagishi . . . stuffed like a deer or a tiger ... in the opening to the right," she had said in fits and starts. After Nicole had regained her composure, the two of them had walked back down the tunnel together. Inside the opening, standing upright just opposite the entrance, Richard had been shocked to see Newton cosmonaut Shigeru Takagishi. He was dressed in his flight suit and looked exactly as he had the last time they had seen him at the Beta campsite. His face was fixed in a pleasant smile and his arms were at his sides.

"What the h.e.l.l?" Richard had said, blinking twice, his curiosity only slightly stronger than his terror. Nicole had averted her eyes. Even though she had seen the sight before, the stuffed Takagishi was much too lifelike for her. They had only stayed in the large room for a minute. Alien taxidermy had also performed wonders on an avian with a broken wing that was hanging from the ceiling next to Takagishi. Against the wall behind the j.a.panese scientist was Richard and Nicole's hut that had disappeared the day before. The hexagonal electronics board from the Newton portable science station was on the floor next to Takagishi's feet, not far from a full-scale model of a bulldozer biot. Other biot replicas were scattered around the room. Richard had started to study the varied collection of biots in the room when they had faintly heard the familiar dragging noise coming from behind them in the tunnel. They had not wasted any more time. Their flight down the tunnel and up the ramps had been broken only by a brief stop at the cistern to replenish their supply of fresh water.

"Dr. Takagishi was a gentle, sensitive man," Nicole was saying to Richard, "with pa.s.sionate feelings about his work. Just before launch I visited him in j.a.pan and he told me that his lifelong ambition had been to explore a second Rama s.p.a.cecraft."

"It's a shame he had to die such an unpleasant death," Richard grimly replied. "I guess that octospider, or one of its friends, must have dragged him down here for a visit to the taxidermist almost immediately. They certainly wasted no time putting him on display."

"You know, I don't think they killed him," Nicole said.

"Maybe I'm hopelessly naive, but I didn't see any evidence of foul play in his ... his statue."

"You think they just scared him to death?" Richard retorted sarcastically.

"Yes," said Nicole firmly. "At least it's possible." She spent the next five minutes explaining Takagishi's heart situation to Richard.

"I'm surprised at you, Nicole/' Richard replied after listening carefully to her disclosure. "I had you figured all wrong. I thought you were Miss Prim and Proper, play it by the rules all the way. I never gave you credit for having a mind of your own. Not to mention a strong streak of compa.s.sion."

"In this instance it's not clear that either was an a.s.set. If I had faithfully enforced the rules, Takagishi would be alive and living with his family in Kyoto."

"And he would have missed the singular experience of his life . . . which brings me to an interesting question, my dear doctor. Surely you are aware, as we sit here, that the odds do not favor our escape. We are both likely to die without ever seeing another human face. How do you feel about that? Where does your death-or any death, for that matter-fit into your overall scheme of things?" Nicole looked at Richard. She was surprised by the tenor of his question. She tried without success to read the expression on his face. "I'm not afraid, if that's what you mean," she answered carefully. "As a doctor I've thought often about death. And of course since my mother died when I was very young, even as a child I was forced to have some perspective on the subject."

She paused for a moment. "For myself, I know that I would like to stay alive until Genevieve is grown-so that I can be a grandmother to her children. But just being alive is not the most important thing. Life must have quality to be worthwhile. And to have quality we must be willing to take a few risks. . . . I'm not being very focused, am I?" Richard smiled-"No," he said, "but I like your general drift. You have mentioned the key word. Quality. . . . Have you ever considered suicide?" he asked suddenly.

"No/' Nicole replied, shaking her head. "Never. There's always been too much to live for." There must be some reason for his question, she was thinking. "What about you?" she said after a short silence, "did you think about suicide during any of that pain with your father?"

"No, strangely enough," he answered. "My father's beatings never made me lose my zest for life. There was too much to learn. And I knew that I would outgrow him and be on my own eventually." There was a long pause before he continued. "But there was one period in my life when I did seriously consider suicide," Richard said. "My pain and anger were so great that I did not think I could endure them." He became silent, locked in his thoughts. Nicole waited patiently. Eventually she slipped her arm through his. "Well, my friend," she said lightly, "you can tell me about it someday. Neither of us is accustomed to sharing our deepest secrets. Maybe in time we can learn. I'm going to start by telling you why I believe we are not going to die and why I think we should go over to search the area around the eastern plaza next."

Nicole had never told anyone, not even her father, about her "trip" during the Poro. Before she finished telling her story to Richard, not only had Nicole covered what had happened to her as a seven-year-old at the Poro, but also she had recounted the story of Omeh's visit to Rome, the Senoufo prophecies about the "woman without companion" who scatters her progeny "among the stars," and the details of her vision after drinking the vial at the bottom of the pit. Richard was speechless. The entire set of stories was so foreign to his mathematical mind that he did not even know how to react. He stared at Nicole with awe and amazement. At length, embarra.s.sed by his silence, he started to speak.

"I don't know what to say . . ."

Nicole put her fingers to his lips. "You don't need to say anything/' she said. "I can read your reaction in your face. We can talk about it tomorrow, after you've had some time to think about what I told you."

Nicole yawned and looked at her watch. She pulled her sleeping mat out of her backpack and unrolled it on the ground. "I'm exhausted," she said to Richard. "Nothing like a little terror to produce instant fatigue. I'll see you in four hours."

"We've been searching now for an hour and a half," Richard said impatiently. "Look at this map. There's no place within five hundred meters of the plaza center that we haven't covered at least twice."

"Then we're doing something wrong," Nicole replied. "There were three heat sources in my vision." Richard frowned. "Or be logical, if you prefer. Wliy would there be three plazas and only two underground lairs? You said yourself that the Ramans always followed a reasonable plan."

They were standing in front of a dodecahedron that faced the eastern plaza. "And another thing," Richard growled to himself, "what's the purpose of all these d.a.m.n polyhedrons?

There's one in every sector and the three biggest are in the plazas. . . . Wait a minute," he said, as his eyes went from one of the twelve faces of the dodecahedron to an opposite skysc.r.a.per. His head then turned quickly around the plaza.

"Could it be?" he said. "No," he answered, "that would be impossible."

Richard saw that Nicole was staring at him. "I have an idea," he said excitedly. "It may be completely farfetched. ... Do you remember Dr. Bardolini and his progressive matrices?

With the dolphins? . . . What if the Ramans also left a pattern here in New York of subtle differences that change from plaza to plaza and section to section? . . . Look, it's no crazier than your visions."

Already Richard was on his knees on the ground, working with his maps of New York, "Can I use your computer too?" he said to Nicole a few minutes later. "That will speed up the process."

For hours Richard Wakefield sat beside the two computers, mumbling to himself and trying to solve the puzzle of New York. He explained to Nicole, when he took a break for dinner at her insistence, that the location of the third underground hole could only be determined if he thoroughly understood the geometric relationships between the polyhedrons, the three plazas, and all the skysc.r.a.pers immediately opposite the princ.i.p.al faces of the polyhedrons in each of the nine sectors. Two hours before dark Richard dashed off hurriedly to an adjacent section to obtain extra data that had not yet been recorded on their computer maps.

Even after dark he did not rest. Nicole slept the first part of the fifteen-hour night. When she awoke after five hours, Richard was still working feverishly on his project. He didn't even hear Nicole clear her throat. She arose quietly and put her hands on his shoulders. "You must get some sleep, Richard," she said quietly, "I'm almost there," he said. She saw the bags under his eyes when he turned around. "No more than another hour." Nicole returned to her mat. When Richard awakened her later, he was full of enthusiasm. "Wouldn't you know it?" he said with a grin. "There are three possible solutions, each of which is consistent with all the patterns." He paced for almost a minute. "Could we go look now?" he then said pleadingly. "I don't think I can sleep until I find out." None of Richard's three solutions for the location of the third lair was close to the plaza. The nearest one was over a kilometer away, at the edge of New York opposite the Northern Hemicylinder. He and Nicole found nothing there. They then marched another fifteen minutes in the dark to the second possible location, a spot very near the southeast comer of the city. Richard and Nicole walked down the indicated street and found the covering in the exact spot that Richard had predicted. "Hallelujah," he shouted, spreading out his sleeping mat beside the cover. "Hooray for mathematics."

Hooray for Omeh, Nicole thought. She was no longer sleepy but she wasn't anxious to explore any new territory in the dark. What comes first, she asked herself after they had returned to camp and she was lying awake on her mat, intuition or mathematics? Do we use models to help us find the truth? Or do we know the truth first, and then develop the mathematics to explain it?

They were both up at daylight. "The days are still growing slightly shorter," Richard mentioned to Nicole. "But the sum of daytime and nighttime is remaining constant at forty-six hours, four minutes, and fourteen seconds."

"How long before we reach the Earth?" Nicole inquired as she was stuffing her sleeping mat into its protective package.

'Twenty Earth days and three hours," he replied after consulting his computer. "Are you ready for another adventure?"

She nodded. "I presume you also know where to find the panel that opens this cover?"

"No, but I bet it's not hard to find," he said confidently. "And after we find this one, the avian lair opening will be duck soup because we'll have the whole pattern."

Ten minutes later Richard pushed on a metal plate and the third covering swung open. The descent into this third hole was down a wide staircase broken by occasional landings. Richard took Nicole's hand as they walked down the stairs. They used their flashlights to find their way, as no lights illuminated their descent.

The water room was in the same place as in the other underground lairs. There were no sounds in the horizontal tunnels that led off from the central stairway at either of the two main levels. "I don't think anyone lives here," Richard said.

"At least not yet," Nicole answered.

48 WELCOME EARTHLINGS.

Richard was puzzled. In the first room off one of the top horizontal tunnels he had found an array of strange gadgets that he had decoded in less than an hour. He now knew how to regulate the lights and temperature throughout each particular portion of the underground lair. But if it was that easy, and all the lairs were similarly constructed, why did the avians not use the lights that had been provided? While they were eating breakfast Richard quizzed Nicole about the details of the avian lair.

"You're overlooking more fundamental issues/' Nicole said, as she took a bite of manna melon. "The avians aren't that important by themselves. The real question is, where are the Ramans? And why did they put these holes under New York in the first place?"

"Maybe they're all Ramans," Richard replied. "The biots, the avians, the octospiders-maybe they all came originally from the same planet. At the beginning they were all one happy family. But as the years and generations pa.s.sed, different species evolved in separate ways. Individual lairs were constructed and the-"