Noise

VI Amplitude

It was not too surprising, Mike told himself later with all the clarity of hindsight, that it was he who found the metal. The background knowledge of the other three had operated against them, though his own lack of Kainuian experience had not really helped at first. It was only after two or three baths when, on his own responsibility, he decided to replace the water he had used that it happened. The other adults were asleep. Leaving Hoani on watch alone had become routine since they had in effect moored the ship to the putative metal source, though he was not at the moment alone. ’Ao was at her masthead. Wanaka pointed out afterward that he should not have gone overboard without having someone else on deck who would not have had to call for help if he got into trouble in the sea, but under the circumstances was quite gentle about it.

It was Hoani’s own slight clumsiness caused partly by his lack of experience and perhaps by a little fatigue that caused the discovery.

The water pods in this pseudoorganism were large, more than three times the volume of those furnished by the iron-fish that had provided his first mining experience at sea. He had collected perhaps a dozen of them, returning each one by one to the ship, and accepting the help of the child in getting them aboard and then into the breakers. ’Ao had descended to the deck when he went overboard. He was beginning to wonder how many more would be needed, so his attention might have been slightly distracted. Also, he was getting a little tired. The pods weren’t very heavy, especially in the local gravity, but the sound armor was somewhat clumsy even for the natives.

In spite of the very low weight he started using both hands to extract and lift each pod from its gelatinous receptacle. Since the pods had only one handle, a simple loop of rope-like tissue, his other hand had to reach into the space underneath the water-filled sack to support it.

And there was another, much smaller pod there. Not attached, but there. In the same pocket as the water. How had the others missed it?

Obvious enough. One handle had been enough for them; they had not felt underneath, and the reddish jelly was much less transparent than that of the iron-fish.

’Ao was at the rail waiting. With his helmet sealed and his hands full, there was no way for him to say anything; but when she saw the tiny—less than ten centimeters long—container, the child, who had taken her full share of the metal search effort since its beginning, made up for his silence both with her own voice and the signal bell. Wanaka and Keo were beside her on the spot in moments, still adjusting face masks.

Mike climbed aboard without attracting, or distracting, their attention, and looked at his discovery over ’Ao’s head.

It was little different in shape from the iron, copper, and titanium pods he had seen before. It was soft to the touch, so the contents were probably in powder form like the others. The color was black, which might have been due either to the fineness of the powder or the composition of the envelope. The captain was weighing it thoughtfully in her hands, tossing it from one to the other, but this could hardly be helpful in guessing at density; there would certainly be space between the tiny grains, and there was no telling from outside what fraction of the whole volume this might represent.

Wanaka finally looked up from the object and caught Mike’s eye. “How did you find this?”

He told her. She and the mate exchanged glances, but no words, which were superfluous. She simply nodded her head toward the others and gestured to the rail. Both flipped on their helmets and disappeared overboard.

One fear, that they might have been wasting days by not looking under the water pods, was quickly dispelled, to be replaced gradually by another. In the first half hour of search, neither the child nor the mate found any more metal.

Wanaka seemed to be on the point of sending Mike into the sea with them, but visibly changed her mind. Instead, she ordered him to stand watch and joined the searchers herself. It was she, some fifteen minutes later, who found the second pod, under a water sack just as the first had been.

By sunset, six more had been located. Since no one had tried to keep track of the area covered or of the number of water pods checked, there was no reliable way to guess at the amount of metal that might be available; it was not even certain whether or not any of the water sources had been counted more than once.

The search was better organized the next morning. Instead of simply groping under each water container and leaving it where it was, the finder removed it from its pit. There was no way to take it all aboard, since the breakers had been filled the day before, and the thought of setting drinkable water adrift would never have occurred to a Kainuian; but since the water itself was fresh, and at this distance from the tropical storm belt the surrounding ocean was quite salty enough even at the surface to let the pods float, they had a compromise. Two hundred meters of line were used, with a pod attached every two meters, to form a ring of water-filled floats; and each new pod thereafter was released inside the ring. By the end of the day, some statistics were available: out of twenty-seven hundred water sites investigated, forty-one had also contained metal. The next day produced a nearly identical ratio.

No one yet could guess what the metal might be.

It was rare, obviously. This did not, unfortunately, mean that it was valuable. While the pseudoorganism might have been deliberately designed, in which case the stuff should be worth keeping, pseudolife was little more immune to natural mutations than any other kind. For a little while Wanaka had been thinking, or perhaps dreaming, of something like silicon, but this was ruled out very quickly. Even in powder form, with presumably nothing but water between the grains, the stuff was much too dense. She thought of platinum and its relatives, though these were useful only in small quantities as chemical catalysts on Kainui, but the creature now calming the sea around them differed greatly from any of the royal-metal trappers to be found either in the reference book or anyone’s memory. For one thing, having water and metal in the same pit seemed to be unique.

Mining boats simply could not carry large amounts of sophisticated analytical equipment like X ray or neutron diffraction cameras or NMR machines. This was a matter of economics, not size. Very rarely a skipper with enough capital might decide to specialize, ship one such device and ignore the commonly traded materials, but Wanaka had never regarded this as a hopeful technique.

She also lacked any reliable way to decide how far from the equator she should ride this possible Golconda. They were already well south of the latitudes maintained by most cities in this hemisphere. Temperatures were dropping, though not yet far enough to affect either safety or comfort. They were riding with the current and pretty well shielded by the organism itself, so there seemed no risk of a serious collision. The winds were weakening; in a few more degrees of latitude they would be in a belt of calms, she knew. This might make it difficult to get back to a city, Keo pointed out.

The captain shook her head negatively. There were cities all over the south temperate zone, though not, of course, in the ice floe regions near the poles; and in any case there would be some chance of meeting other ships. If the metal were worth trading, of course…

The crudest of tests—exposing a small sample of the material to the quite acidic sea water—eliminated the alkali and alkaline-earth metals at once, and made items like zinc and even tin unlikely; density had already ruled out most of the latter anyway.

Wanaka was becoming irritated. “Mike, you’re a linguist, aren’t you?”

“If anything, more of a historian, Captain.”

“Not a chemist.” There was no question mark.

“Well, Captain, I learned what you might call—”

“Not a chemist.”

“No, Captain. I could figure an equilibrium constant if you gave me the electrode potentials involved, but—”

“Would that help with this problem?”

“It might, but you—”

“But I don’t have a handbook with the potentials.”

“I don’t suppose so, Captain. I have no equipment to measure them, either.”

“Then we’d both have saved breath if you’d stopped at ‘No’ a few sentences ago.”

“Yes, Captain. Sorry.”

“I’m sorry, Mike. I’m getting bothered by all this. I know what I should do, but can’t make myself do it. I’m setting a very bad example to ’Ao, too, and I suppose I’m letting you in for more risks than you bargained for.”

Mike grinned behind his mask, and gestured quickly, “I’m not bothered. There’s nothing that’s happened yet that hasn’t been interesting.” He was not exactly lying, but tact seldom is. Not exactly. “I’ll be able to write an adventure story as well as a thesis.”

“And you haven’t done anything that was a bad example to me,” ’Ao shrilled, “except that time when—”

“You asked for that,” Wanaka cut in firmly, “and you’ve earned back more points than you lost then anyway, which was zero. I’m not apologizing for anything. We’re staying with this creature as long as we possibly can, and that could be pretty long, considering the water situation.”

“Then we’d better keep on collecting this stuff, whatever it is,” pointed out Keo, “and treat it a little more carefully than we have been. The little screen says it’s not very radioactive if at all, but it could be as poisonous as osmium or nickel, say.”

So they collected carefully, without the help of Mike or of ’Ao, who as a growing child should not be exposed to chemical risks if at all possible. She made no objection, and both of them as the days passed grew a little casual about marine discipline, especially in the matter of conserving fresh water.

Storms and waterspouts were becoming a little less frequent as their distance from the equator increased; the surface water was saltier as well as cooler, and had a lower vapor pressure. Extremely well-focused sound waves should not, of course, be affected by this factor; but Keo, who had made such a point of their rarity, began to wonder if they might not be favored by it. Twice in the space of a few days they occurred within sight of the ship, once a couple of hundred meters beyond the edge of the metal-maker and once actually within it too close for comfort to the ship, tearing a two-square-meter patch of the jelly loose and hurling it far into the air. The only one to react visibly was ’Ao, who looked down at the mate from her crow’s nest in rather critical fashion the second time.

The stock of metal grew very slowly, of course, but it did grow, and eventually Wanaka developed a new worry. Did they now have too much of the stuff to be safe? At Muamoku’s latitude, if they decided to go there, the ocean would be decidedly less salty and Mata would float correspondingly lower. Sadly, there was no way of calculating “correspondingly,” since there was no precise measurement of Mata’s depth-versus-displacement function on hand.

And would it be a good idea to bring the material back to the city at all? The captain found herself developing a touch of Mike’s fear of looking silly, with much better reason for it than he usually had. Spending weeks or seasons collecting something completely useless, however excusable by the circumstances, would certainly make her colleagues and competitors smile behind their masks, and in a city there’d be no masks to hide the smiles.

Maybe it would be better to get away from this creature and simply cruise around, remaining in deep-south latitudes, of course, but not going as far as the ice, or even the calms, hoping to find another ship rather than a city, and trade off some of this stuff before going home.

She could tell, with perfect truth, why it might be of unheard of value. The opposite possibility would be obvious to any competent trader, so there would be no need to mention it aloud, and practically any skipper would be willing to take at least some of her stock on chance, she was sure.

So she finally ordered the loading to stop. Plimsoll marks didn’t grow automatically on hulls, and the paint certainly provided none; there was no more magic in nanotechnology or pseudobiology than in “real” life. She and Keo spent some time trying to calibrate Mata’s still unmeasured displacement. Their guesses were based mainly on the assumption that it wouldn’t differ much from Malolo’s. Memory provided some highly imprecise estimates of those.

It also took a day or so for her really to make up her mind to abandon the vast supply of fresh water now floating in its pods beside her ship. She did not actually let it go, finally; she moored it to the remains of Malolo, still anchored to the nameless organism by her sea-anchor equipment.

She couldn’t quite decide whether to hope that someone would find it, or not. She wasted no actual time on the question since she had no real faith in the efficacy of hope.

Mike suspected a little of this, though much less of it came up in conversation. He was mainly going by the length of time it was taking the captain to announce decisions.

She hesitated only once more. ’Oloa, on request, reported that their latitude was forty-three degrees south, which agreed with the rudely measured apparent height of the noonday suns. Wanaka decided to wait until it was just forty-five before leaving the scene. She offered no explanation, though even Keo raised an eyebrow. ’Ao showed no reaction; Mike wondered whether she was afraid of losing more points, or was genuinely indifferent. He himself would have preferred, by now, to get on with whatever might be going to happen next.

He was therefore somewhere between relieved and delighted when ’Ao, who was again spending most of her time at Mata’s masthead, called out, “City! A hand south of east!”

What they all saw was certainly city-sized, looming indistinctly through a kilometer or so of haze. Even to the Earth native, however, and at this distance through the haze, there was something about it that did not suggest human design. It was not very dark in color, rather a light gray, with an occasional brief sparkle that might have meant fabricated metal. Unusually for him, he expressed the doubt aloud.

“Are you sure, ’Ao?” he asked. “I’ve only seen Muamoku, I know, and I suppose cities differ from each other, but still—” He doubted this on-the-spot conclusion even as it left his lips. Cities on Kainui all had the same environment and faced the same engineering design constraints. They should be pretty similar. He did not end his sentence, and closed with “Are you sure?” again.

“What else could it be?” the child responded indignantly. “There’s nothing else in the world anywhere near that big.”

“You mean that high out of water,” Keo corrected.

“Of course I do. Metal-fish are bigger,” granted the child. Even Mike could feel her effort to make the lack of precision seem unimportant. “But I couldn’t have seen a metal-fish or anything except a city that far anyway.”

“Of course you couldn’t,” the captain interjected soothingly, “but how about Mike’s question? Are you really sure that’s a city? We’re heading within a few degrees of it; keep your eyes bright and let us know when you spot anything strange.”

Everyone noticed the “when,” but only Mike wondered whether the captain, too, thought there was something odd in the sighting or whether mere wish might be involved. He felt pretty sure by now that Wanaka was in no real hurry to reach a city. She was not actually an indecisive person—no one in her position could be—but, at the moment, would have been very pleased with any source of data that might make decisions less nebulous.

“Don’t spend all your time looking at that hump. Check for ships in the neighborhood,” she added to ’Ao after a few minutes. Hoani conceded her a point; there had always been scores of full-sized ships and smaller vessels busy, and visible if close enough, within a few kilometers of Muamoku. He had seldom known just what they were about, but they had been there. Of course, Mata was too far yet to let ’Ao spot such an entourage, but he, too, followed Wanaka’s order as well as he could from deck level.

The captain’s next command, only a few minutes later, fully restored Mike’s normal tendency to keep his question count low. It was called to the masthead, but not to ’Ao.

“’Oloa! Look as closely as the haze will let you for the next few minutes, and see whether you can figure how much of that thing’s motion is due to wind alone. A city’s floats wouldn’t reach very deep. You know what the shallow currents are from this metal-maker’s drift. Is there any sign that the big thing is being influenced by deep currents as well as wind?”

The doll’s tiny voice was inaudible over the background noise, of course, but ’Ao reported that it had acknowledged the command and was presumably obeying.

The object was farther away, and much larger in size, than anyone had guessed at first. One side of its water line was now almost on Mata’s course as she was borne along by the metal source; the other, Keo and Wanaka judged as their viewing angle changed and gave them a better idea of its size, must extend at least two kilometers to the left of it. It was certainly not following surface currents, though the wind should be having some influence on anything that size; its peak seemed three hundred meters or more above the sea, though estimation was difficult. As it neared, the general gray tone showing through the haze became patchier. The spots reflecting the sparkles of sunlight remained too small to show any details, but did grow brighter.

“Hadn’t we better get out of this mess so we can maneuver, before it’s too close?” suggested Keo. Wanaka shook her head slowly.

“Anyone spotted any boats?” she asked, loudly enough to be heard aloft. No one had. ’Ao, however, saw something.

“There are floating things. Not boats. Some of them are almost black. Some of them might be ice floes—but remember I’ve never actually seen one of those. Just pictures. These are sort of humped up out of the water, and I thought ice floes were pretty flat. If they’re mostly ice, they must go too deep to get over this creature we’re on; but if they’re shallow-draft enough to float over it, maybe we’d better get clear. We’re not actually aground on it, but it sometimes humps up enough to push on the keels, and it’ll drag on them if we’re sailing. I can feel that from up here.”

Wanaka took the advice, to the child’s delight. “Right, ’Ao. Quarter sail, Keo; if we do hit anything, we don’t want to hit it hard. Head us to starboard of the big lump. ’Ao, keep us clear of any small ones. There shouldn’t be much ice until we’re farther south, of course, but you’re right. Some of those bits could be floes, and we certainly don’t want to hit the higher stuff.”

A thought struck Hoani, and after a moment he decided it offered an excuse for a question. “You said something, a long time ago, about people who assembled bergs—big ice masses—and rode them into city latitudes to sell for water.”

“So I did. But this is a hundred times as big as anything of that sort I ever heard of. Besides, all that was long ago, early in history. Of course, someone may be playing with some improved technique. That may be why it doesn’t all look like ice.”

“And why I thought it was a city.”

“A bigger berg would lose a lot smaller percentage to melting in a given time,” Mike remarked.

“So it would. On the other hand, a piece of ice that size would lose most of itself to melting before any city could use much of it up. I don’t see why anyone would make one that big. ’Ao, take a look at that thing and see if you can spot any people on it.”

“Can’t, tautai. There’s too much of this smaller stuff floating around us, and I have to watch that. We’re starting to move, so I won’t be able to look out for anything else. Mike has good eyes, though.”

For the first time since reaching adulthood, Mata was moving under her own sail, drifting slowly over the jelly, dragging on it sometimes, but finally reaching not very open sea. Nothing, as far as anyone could tell, was under her keels but water for nearly three thousand vertical kilometers.

The huge drifter was less than a kilometer away by now.

“’Oloa, do you think it’s mostly wind or mostly current?” Wanaka called to the masthead. The doll’s owner answered.

“She’s not sure, since she doesn’t know how deep it goes, but there must be a good deal of deep current. She says to tell you, ‘Three unknowns at least, only one equation.’ I don’t know what she means, but those were the words.”

“I do. Thanks,” shouted Wanaka.

Mike knew, too, and assumed that Keokolo did.

Keo, at the tiller, guided them close enough to one of the small floating objects to give everyone a good look. For a minute or two they examined it silently.

It was about three meters across and extended something over half that distance above the surface. If it had much vertical symmetry, which seemed doubtful, it must be nearly spherical. There was indeed ice covering much of the thing, but under, or inside, that ice was some much darker material. Keo hove to, a few meters from whatever it was, without waiting for orders. Its motion was almost entirely current controlled, apparently, like their own at this point.

“Shall I take a real look, Captain?” asked the mate.

Wanaka shook her head negatively. “Mike,” she said slowly, “take a safety line and see what you can make of it.”

The order made sense. The thing was unfamiliar to the natives; Hoani was as likely as they to make some sense out of it—perhaps more likely. If he got into trouble, Wanaka and Keokolo were much better qualified to help him than he would be to help them. He flipped his helmet forward, latched it, and went overboard. Two or three strokes, even with his limited—by Kainui standards—swimming skills, brought him against the object. He could not, of course, remove his helmet, but the others were close enough to read his fingers. He reported after only a minute or two of examination.

“The light stuff is ice, all right. It should be melting; I suppose it is. It feels a lot colder than the water. What there is above the water line is mostly dark stuff glued together by ice, but just below the surface and as far down as I can see there’s more ice and less of the dark stuff. It’s mostly orange and red in color. Just a minute. It’s either bobbing up and down a lot, or staying put as the waves pass; there’s no telling which.” The others had seen this already, and given up much hope of Mike’s being able to make a detailed examination, but Wanaka made a brief, encouraging gesture.

Mike turned back to the floe for a moment, then faced Mata again with a golf ball-sized fragment that showed no ice coating at all resting on his palm, and held it up for the others to see. “Shall I bring this aboard, or could it be something that shouldn’t touch the hull?”

“Bring it. Just don’t pound on anything with it,” replied the captain. Keo gently pulled Mike back by his safety line, allowing him to give full attention to keeping the specimen from striking the hull. Hoani reached up, handed it to Wanaka, and climbed aboard. Examination was interrupted briefly by a call from the masthead.

“Keo! Maneuver! There’s another one closing in.” The mate sprang to the tiller, and started to work Mata over to a less crowded area. The motions of the floes had a random component; they were high enough to be affected by wind, but no two were more than vaguely alike in shape. The captain stopped him almost at once. “Heave to again. There’s no dodging everything. Look.” She gestured around.

Every two or three meters there floated a dark, apparently ice-free fragment of the red-brown material. The hulls had already struck a number of the pieces, apparently with no damage; the impacts had not been hard enough to attract attention, though Hoani suspected there’d better be another close paint check before long. He lay down on the deck, reached overside, and picked up a much larger ice-free piece. This one crumbled into almost invisibly small particles in his grip.

The fragments that fell back into the water sank at once, to his surprise. He thought about this for a moment while getting back on his feet. The others had not, apparently, seen; the adults were still examining the first specimen, and ’Ao on her masthead wasn’t close enough.

The captain looked up, first at the mate and then at Hoani.

“’Amu,” she said firmly, “but I’ve never seen any just like this. Have you, Keo?”

To Mike, the word was a general Samoan one for coral, but must, he was sure, carry a different meaning here; this ocean was far too acidic for anything made of calcium carbonate, and silica wasn’t an option.

“The big pieces float higher than ice,” he pointed out vocally. The others looked at him quizzically. He lay down once more, reached overboard, and repeated his previous attempt to pick up one of the dark floating fragments. The result was the same, including the behavior of the crumbled bits. Wanaka nodded thoughtfully.

“Full of air cells whose walls break very easily. I wonder why they last as long as they do? That whole piece pulverized under finger pressure, but some of them have hit the hulls time after time without collapsing; and that big chunk you took this one from…I don’t understand. Does this remind you of anything you’ve seen on Earth—or anywhere else?”

Mike had to admit it didn’t.

“Air cells would account for the low overall density,” he admitted slowly, “and the actual cell walls must be a lot denser; but why are they so fragile under one treatment but hold together, as they’d pretty well have to, under storms, waves, hail, and other ways this world of yours can beat things up?”

Since he had merely restated Wanaka’s implicit question, he got no answer.

’Ao called their attention to another bit of data.

“Look! The big piece is turning over!”

It was, though not very rapidly. The side toward Mata was rising, revealing a new ice-coral mixture. Mike wondered briefly whether his removal of a few grams from the near side had upset some remarkably delicate equilibrium, but decided as the turning went on that this couldn’t be the answer. The lump did not stop rolling until it had made something like a third of an overturn. Not an exact half, they all could see, though it was now evident that its overall shape was very nearly a sphere.

The masthead made another report. “There’s a little more ice showing in what’s just come up.” There was a brief pause, then, “’Oloa says we all should see that the ice is denser than the other stuff, and says I should be able to tell her why the big lump turned over. I can’t, right now. How long do I have before I lose points?”

“At least an hour after one of us figures it out,” Wanaka answered promptly. Then she added, “And if that takes more than ten minutes, you don’t lose any.” The doll’s voice could just be made out in a momentary pause in the thunder, but its words were indistinguishable to Mike. If they carried any meaning to the captain, she did not relay it.

It was evident that there was no use trying to dodge all the flotsam. If it were going to do any damage, it had probably already done it. Keo, at the captain’s orders, got under way again, though very slowly indeed—they were still avoiding the larger collections of ice and coral. The city, which it probably wasn’t, still floated with its near side about half a kilometer away, and a trader would no more forgo a closer look than would a scientist.

The fine bits of coral were everywhere; there was no avoiding them. The larger chunks of ice-coral mixture, many up to ten meters across, were no problem. Twice, as they passed close to one of these, it turned itself leisurely over; the roughly spherical shape was starting to seem reasonable to the adults, but well over ’Ao’s allotted hour had passed before any of them actually worked out the cause. As usual, it was embarrassingly simple. Keo, for good reason, saw the answer first.

He was still at the helm, and had been watching a particularly large chunk for many minutes, since their course lay quite close to it. It slowly dawned on him, as they neared, that it was not now turning over but was, very slowly indeed, rising. There was more of it out of the water than had been the case five or six minutes before. Then as Mata reached the nearest point to it on her course, the turnover started with unusual speed. This time, again, the near side was rising, and without waiting for orders the mate steered even closer. Wanaka seemed about to say something, but apparently decided to trust the helmsman.

He used voice, and his tone held satisfaction.

“I get it. I see what ’Oloa meant. The ice is denser, and of course the part under water melts faster. The body rises, and its center of gravity rises faster because it’s the part under water that’s losing weight. When the center of gravity gets higher than the center of buoyancy, it has to turn over. Anyone who’s ever planned a boat knows that. Since the things aren’t perfectly round, and probably don’t have the same density all through, they don’t always tip in the same direction or by the same amount.”

The others nodded slowly, and Wanaka called the information up to the masthead. ’Ao, while long since relieved from the worry about losing points, was audibly annoyed at not having worked the answer out for herself. She had, after all, been taught the relevant physics, like anyone who would be expected to spend her entire adult life between floating cities and boats.

They had reduced their distance from the “city” to a few hundred meters when the child restored her own self-respect.

She called a question down from her perch. It was carefully not worded as a warning or even a question, of course, but it deflected the thoughts of all three adults onto an interesting line.

“I wonder how often this big thing turns over…and which way is next.” Wanaka and Keo reacted, but not verbally.

The basic wind was still fairly strong at this latitude, but its direction was inconvenient. Keokolo had to tack several times. He also made skillful use of the more or less random gusts around two local storms, in a maneuver that Mike thought of as slingshotting; but it was over an hour before they were out of the thickest part of the flotsam. Even then, three of the crew felt a little uneasy whenever they looked back at the huge drifter; their line of sight was still uncomfortably upward. That was unusual on Kainui.

Wanaka looked straight back, without any upward component to her line of sight, and a frustrated expression showed around her mask.

“Well, it can’t be a city, but there’s a lot more there than ice. I wonder what it would be worth?”

“We could wait until it does roll. Then there’d be plenty of time before it happened again,” suggested ’Ao.