Part 3

He got out his equipment and materials and spread them out. There was no need to build a recorder, since there was one among the supplies. The rest wouldn't be unduly difficult. He established a working space and set systematically to work. The task he'd accepted was essentially simple. A submarine ear was to pick up underwater sounds. He had to modify a microphone and enclose it in a water-tight housing, with certain special features that would make it highly directional. The recorder would take the pick-up and register it on magnetic tape, while playing it for simultaneous listening. Then he had to assemble a machine for playing back the taped sounds under water. That required a unit for a submarine horn, to broadcast the amplified sound. It isn't difficult to make a sound under water. One can knock two stones together under the surface and a swimmer can hear it a mile or more away. But a horn to reproduce specific sounds is more difficult to build. It needs extra power. A sound-truck in a city, competing with all the traffic noises, will turn no more than fifteen watts of electricity into noise. But much more power would be needed to produce a similar volume under water.

Terry modified the mike into a submarine ear--an _orejas de ellos_. Then he began to assemble an audio amplifier to build up the volume of the sounds already taped for re-use under the sea. He had the parts. It was mostly just finicky labor. He sat cross-legged in the sunshine, not far from the _Esperance's_ unusual winch.

Nick came up from below and went aft. He spoke to Davis. Terry couldn't hear what was said, but Davis gave orders.

The _Esperance_ heeled over; away, away over. The four crew-cuts adjusted the sheets for maximum effect of the sails on the new direction of motion. The yacht seemed to tear through the water like a racing boat. Terry had to rescue some of his smaller parts which started for the scuppers. He looked up. Deirdre said cheerfully, "Our radar picked up a boat that's probably _La Rubia_ on the way back to Manila. We don't want her to see us."

Terry blinked.

"Why?"

"We're going to take a look at the spot where we think she catches her fish," said Deirdre. "It's strange enough that she catches so many, but what's even stranger is the kind of fish she catches at times."

"How?"

Deirdre shrugged. Then she said irrelevantly, "_La Rubia's_ skipper would like to have the only radar in the world, as you've reason to know, and he doesn't think of radars, except his own and possible competitors. But there are lots of others. We're probably a blip on somebody's radar-screen right now. In fact, we're supposed to be. So when my father got interested in _La Rubia_ and her--catches, he was able to have somebody notice where she goes every time she slips away from the fishing fleet. And so he was told. It was all quite unofficial, of course."

Terry bent over his task again while the _Esperance_ sped along over the off-shore swells. There was no land in sight anywhere. An albatross glided overhead for a time, as if inspecting the _Esperance_ as a possible source of food. When Terry looked for it later it was gone. Once there was a flurry in many wave-flanks, and a small school of flying fish darted out of the sea with hazy, beating fins, and dived back into the sea many yards from where they started.

But nothing of any consequence happened anywhere. Terry fitted and soldered and tested. By noon he had a rather powerful audio amplifying unit, set up to magnify any sound the tape-recorder fed into it. Deirdre prepared a meal. The galley of the _Esperance_ was admirably supplied with all kinds of food. After the noon meal the yacht changed course again to a line which would intersect her original morning course at some point.

Terry found himself fuming. He'd set to work to make something that Davis apparently wanted, but his most elementary questions still ran against a blank refusal to answer. Both Davis and Deirdre had spoken of oddities in the catches of _La Rubia_. There could not possibly be any reason for them to refuse to tell him what they were. Terry worked himself into irritability, recalling how he volunteered to come on the _Esperance_ but not thinking that he would be treated as someone who wasn't allowed to know what everybody else aboard most certainly did.

In the afternoon there was guitar music down in the forecastle, and Doug came out and settled himself on the bowsprit with a book of poetry. Presently Nick sat down close by Terry and watched interestedly as he put mysterious-looking electronic elements together into incomprehensible groups. When he had finished, Terry did not admire his handiwork. The noisemaking unit came last. The electrical part had to be enclosed, water-tight, with a diaphragm exposed to the water on one side and its working parts protected from all moisture on the other. The device looked cobbled, but it worked, and made monstrous sounds in the air.

Now he plugged the submarine ear into the recorder. He dropped it overside and taped the random noises of the sea: the washings of sea water against the _Esperance's_ hull, frequent splashings, and very faint, chirping noises from who-knew-what.

"Watch the volume, will you?" Terry pointed out the Indication that should not be exceeded. Nick nodded. "I'm going to whack the paddle overside and see what we get in the way of noise."

Nick hesitated. Then he said uneasily, "Wait a minute."

He went aft to Davis, apparently somnolent at the wheel. Deirdre joined the two of them in a seemingly very serious discussion. Then she walked over to Terry.

"I hate to say it," she told him with evident concern, "but my father thinks it would be wiser to try out the paddle in shallow water. Do you mind?"

"Yes," snapped Terry. "I do mind, since I'm not allowed to know the reason for that or anything else."

He put away his tools and the unused parts. He pointed to the machines he had already built.

"This is what your father wanted, I think. After it's tested I'll ask you to put me ashore."

He went below, where he fretted to himself. But no one came, either to inform him of Davis' reasons, or to tell him to do as he pleased. He felt like a child who isn't allowed to play with other children; who is arbitrarily excluded from the purpose and the excitement of his fellows. Thinking in such terms did not make him feel any better. His irritation increased. The _Esperance_ was engaged in an enterprise that these people considered very much worth doing. He'd joined them to accomplish it, and they wouldn't tell him what it was. He hadn't the temperament to be content with just following blindly. And somehow the fact that Deirdre was aboard and a participant in the secret made his exclusion an insult.

He felt about Deirdre that urgent concern that a man may feel about one or two, or at most three girls during his whole lifetime. It wasn't a romantic interest, at this stage, but he wanted to look well in her eyes, and he was enormously interested in anything she said and did. If he left the _Esperance_ and ceased to know her, he knew he'd be nagged at by the feeling that he'd made a very bad mistake. He didn't want to stop knowing her. But he refused to be patronized.

He saw an open book on the after-cabin table and glanced restlessly at it. There were three or four photographs and a newspaper clipping stuck into its pages. The book itself dealt with physics at post-graduate levels--which meant that it included a good deal about electronics.

Still fuming, Terry glanced at the pictures. The first was of a spherical object made of transparent plastic and probably of small size. It had a number of metallic elements clearly visible through the transparent case. It looked as if it might be an electronic device itself, but there was no sign of lead-in contacts, and the parts inside made no sense at all. The second and third photographs were of a similar yet slightly different object. The fourth photograph was a picture of what looked like ocean water, taken from a plane. The horizon showed in one corner. The center of the picture was an irregularly-shaped mass of white. On close examination it appeared to be foam. But it looked as if it were piled up in masses above the surface. If the water around it was ocean--and it was--and the visible crest-lines were of waves--and they were--that heap of foam must have been hundreds of yards in diameter and piled many feet high on the surface. Foam does not form in such masses in the open sea. It would not last if it did.

On the margin of this picture a date had been inked--three days before--and a position in degrees of latitude and longitude.

Terry turned to the chart rack. He pulled out a chart and looked up the position. Someone had made a pencil-dot there. It was close to Thrawn Island, on the very brink of the Luzon Deep, that incredible submarine chasm in which the entire Himalayan chain could be sunk without showing a single pinnacle above the surface.

He went back to the clipping. It was dated Manila, two years earlier. It was an obviously skeptical article on a report made by the crewmen of a sailing ship that stopped by Manila. Sailing ships are rare enough in modern times. This ship reported that she had sighted another of her own kind at sea. The two ships altered course to speak to each other. And the one which came into Manila declared that when the other vessel was no more than two miles away, white foam suddenly appeared on the sea just in front of her. A geyser of unsubstantial white stuff spouted up and spread, shooting up about thirty feet on the water. The bow of the other sailing ship entered the foam patch. And suddenly her bow tilted downward, her masts swayed forward, and the entire ship vanished into the white stuff, exactly as if she had sailed over a precipice. She did not sink. She dropped. She "fell" under water--under the foam--her sails still spread. One instant she sailed proudly. The next instant she was gone.

The position of such an incredible happening was roughly given. It was almost exactly the same as the position written on the photograph of foam taken from the air. At the margin of the Luzon Deep.

Terry found that his indignation had evaporated. The reason for it still remained, but now he wanted to know more about this happening and about the spheres of plastic with those deftly designed but enigmatic inclusions. The plastic objects had a purpose. He wanted to know what. And the news clipping....

Having announced crossly that he would ask to be set ashore as soon as the fish-driving unit was tested, he was ashamed to take it back. He stayed below, now angry at himself again. Nobody came below. Deirdre did not descend to cook. Night fell. Well after nightfall he heard movements on deck, and presently a voice which sounded oddly distant. The _Esperance's_ course changed abruptly. The quality of her motion altered once more.

He went abovedecks. Twilight was long over, but the moon was not yet up. Here and there a wave-tip frothed, and blue luminescence appeared. Here and there a streak of dim blue light could be seen under water, where some fish darted. But those dartings were rare. Despite the yacht's shining wake and the curling wave-tips, the sea was darker than usual.

Nick's voice came from aloft, faint and eerie and seeming to come from the stars.

"... farther to port.... Two points ..."

Terry could see the masthead weaving and swaying against the stars, with a small dark silhouette clinging to it: Nick. The yacht began to swing. On one bearing she pounded heavily. The seas could hit her squarely, and they did. Figures moved swiftly about the deck, loosening sheets or tightening them. Nick's voice again, from overhead.

"Stea-a-a-dy!"

The _Esperance_ ceased to turn. Rushing, pounding water sprayed in the air. The waves splashed upon the hull of the yacht, which was sweeping along on a quartering wind.

For a while no one talked. Tony stood at the wheel, with Davis nearby, by the binnacle light. Terry could see Davis glancing into the binnacle, then gazing at the horizon ahead, and then aloft, where Nick seemed to swing among low-hanging stars.

"Ri-i-i-ght!" he called from high overhead. "Steady as she goes."

The _Esperance_ sailed on, over the surging seas. Waves came out of nowhere, leaped beside the yacht and then went by--to nowhere. It was hard to believe that the yacht actually moved forward. She seemed to stay perpetually in the one spot. But there was a winding, sinuous wake, and there was froth under her forefoot.

Then a vague brightness appeared on the sea, at the limit of vision. It spread out more widely as the _Esperance_ approached. Presently it was clearly visible.

Dead ahead, the beam of the headlight suddenly revealed an incredible spectacle. Until then there had been just a few flashes in the water, where some fish darted away from the yacht's bulk. But here the entire surface of the water shone with thousands and thousands of fish. They were packed in a sharply delimited circle about a mile wide. When the _Esperance_ got close enough, she hauled up into the wind to look.

From a spot fifty yards ahead, the sea was alive with a million frantic dartings of swimming things. They were crowded, packed almost fin-to-fin. And it was not a surface phenomenon only. From the yacht's deck the streaks of light were visible deep down, as far as the clear water would let them be seen. They formed a column of glittering chaos. The vast circle, to an indefinite depth, was packed solid with agitated fish. At that edge of brightness the thronging creatures were splashing in a mad frenzy. Solid shining shapes leaped crazily from the water. Some leaped again and again, until they reached the spot where the flashes were thickest, and got lost in the multitude of their fellows. A few escaped to the darker surrounding sea. They seemed to run away in stark terror. But those were only a few. The greatest mass of fish milled crazily inside the circle. There were even porpoises, darting about as if frightened beyond all normal behavior, not even trying to feed on the equally fear-maddened creatures all about them.

_Three_

Terry stared incredulously. Someone moved beside him. It was Davis. He spoke in a dry voice.

"I would think," he said detachedly, "that _La Rubia_ could catch a boatload of fish in that water with a single haul of her nets. Certainly with two."

Terry turned his head.

"But what is it? What makes these fish gather like this?"

"An interesting question," said Davis. "We'll try to find out how it happens. Even more interesting, I'd like to know why."

He moved away along the deck. Terry went close to the side rail. A few minutes later the startling glare of one of the side searchlights smote upon the water away from the incredible scene. It moved slowly back and forth. Where the light struck, the sea seemed totally commonplace. No fish could be seen. Then the white beam swept here and there in jerky leapings. There was nothing unusual on the surface, nothing beyond the limit of brightness, where the sea turned dark.

Deirdre said at Terry's side, "We didn't really expect this! I'm going to get a sample of the water, Terry. Want to help?"

She ignored his haughty withdrawal of the afternoon, and he could not stand on his dignity in the presence of such an incredible phenomenon. She got a water bucket from the nearby rack. A wave sprung up as she tried to fill the bucket overside. It touched her hand and she cried out. Terry jerked her back by the shoulder. The bucket bumped against the _Esperance's_ side, hanging on the line attached to the rail.

"What's the matter?"

"It stung! The water stung! Like a nettle!" Shaking a little, Deirdre rubbed her wet hand with the other. "It doesn't hurt now, but it was like a stinging nettle--or an electric shock!"

Terry hauled in the bucket and set it down. He leaned far over the rail. He plunged his hand into a lifting pinnacle of the sea. Instantly, his skin felt as if pricked by ten thousand needles. But his muscles did not contract as they would in an electric shock. The sensation was on the surface of his skin alone.

He shook his head impatiently. He put his finger in the bucket he'd lifted to the deck. There was no unusual sensation. He dipped overside again. Again acute and startling hurt, from the mere contact with the water.

Deirdre still rubbed her hand. She said in a queer, surprised voice,

"Like pins and needles. It's like--like the fish-driving paddle! But worse! Much worse!"

Terry looked again at the sea glittering with the swarms of fish in hopeless, panicked agitation, confined in a specific narrow compass by something unguessable. The searchlight continued to flick here and there. The _Esperance_ drifted away from the edge of brightness. Terry put his hand overside once more, and once more he felt the stinging, nettle-like sensation. He got a fresh bucket of water from overside. On deck, there was no strange sensation when he dipped his hand in it.

The searchlight went out abruptly and only a faint and quickly dimming reddish glow came from it. That too died.

Davis' voice gave orders. Terry said sharply, "Wait a minute!" He began to explain about the stinging of the water. But then he said, "Deirdre, you tell him! I'm going to put a submarine ear overboard. At the least we'll get fish noises on a new scale. But I've got an idea ... don't sail into the bright circle yet."

He got out the submarine ear and the recorder he'd made ready that afternoon. He started the recorder. Then he trailed the microphone overside. The sounds would be heard live through the speaker and they would be taped at the same time. At first, a blaring, confused sound came through. Terry turned down the volume.

He heard gruntings and chirpings and rustlings. Fish made those noises--not all fish, but certain species. These shrill, squeaking noises were the protests of frightened porpoises. But under and through all other sounds, a steady, unvarying hum could be easily detected. Terry had never heard anything quite like it. Its pitch was the same as that of a sixty-cycle frequency, but its tone quality was somehow sardonic and snarling. The word that came into Terry's mind was "nasty." Yes, it was a nasty sound. One didn't like it. One would want to get away from it. In the air the same unpleasant sensation is produced by noises that make one's flesh crawl.

Terry straightened up from where the recorder played upon the wet deck. Davis and Deirdre had come to listen, in the strange darkness under the sails of the _Esperance_.

"I've got a sort of hunch," said Terry slowly. "Let's sail across the bright patch. I'll record the sea noises all the way. I've a feeling that that hum means something."

"It's not what you'd call an ordinary sound," said Davis.

He raised his voice. One of the crew-cuts was at the schooner's wheel. He spun it. The sails filled, and the rattling of flapping canvas died away. The _Esperance_ gathered way and moved swiftly from the glittering circle, came about, and sailed again toward the shining area. She got closer and closer to the boundary.

The recorder continued to give out the confused and frightened noises of the sea creatures, but under and through their sounds there remained the nasty and sardonic hum. It grew louder and more unpleasant--much louder in proportion to the fish sounds. At the very boundary of the bright space it was loudest of all.

But as the yacht went on, the hum dimmed. At the very center of the circle where the glitterings were brightest, the humming sound was overwhelmed by the submarine tumult of senseless fish voices. Terry dipped his hand here. The tingling was almost tolerable, but not quite.

Davis hauled more buckets of water to the deck. In two of them he found some fish, so dense was the finny multitude. Then the yacht neared the farthest limit of the bright circle. The hum from the recording instrument grew progressively louder. Again, at the very edge of the shining water, it was loudest.

The _Esperance_ sailed across the live boundary and into the dark sea. As the boat went on, the sound dimmed....

"Definitely loudest," said Terry absorbedly, "at the edge of the circle of fish. At the line the fish couldn't cross to escape. It is if there were an electric fence in the sea. It felt like that, too. But there isn't any fence."

Davis asked evenly, "Question: what holds them crowded?"

Terry said again, groping in his mind, "They act like fish in a closing net. I've seen something like this once, when a purse-seine was hauled. Those fish were frantic because they couldn't get away. Just like these."

"Why can't they get away?" asked Davis grimly. "We haven't seen anything holding them."

"But we heard something," pointed out Deirdre. "The hum. That may be what closes them in."

Her father made a grunting noise. "We'll see about that."

He moved away, back to the stern. In moments, the _Esperance_ was beating upwind. Presently, she headed back toward her previous position, but outside the brightness. Terry could see dark silhouettes moving about near the yacht's wheel. Then he saw another brightness at the eastern horizon, but that was in the sky. Almost as soon as he noticed it, the moon peered over the edge of the world, and climbed slowly to full view, and then swam up among the lower-hanging stars.

Immediately, the look of the sea was different. The waves no longer seemed to race the darkness with only star glitters on their flanks. The figures at the _Esperance's_ stern were now quite distinct in the moonlight.

"You said a very sensible thing, Deirdre," said Terry. "I thought of the fish-driving paddle and its effects, but I was ashamed to mention it. I thought it would sound foolish. But when you said it, it didn't."

"I have a talent," said Deirdre, "for making foolish things sound sensible. Or perhaps the reverse. I'm going to say a sensible thing now. We haven't had dinner. I'm going to fix something to eat."

"You won't get anybody to go belowdecks right now!" said Terry.

"I thought of that," she told him. "Sandwiches."

She went below. Terry continued to watch, while figures at the stern of the schooner went through an involved process of visual measurement. It was not simple to determine the dimensions of a patch of shimmering light flashes from a boat in motion. But presently, Davis came toward him.

"It's thirteen hundred yards across," he told Terry. "Plus or minus twenty."

"I didn't expect all this," Davis said, frowning. "I've been making guesses and hoping fervently that I was wrong. And I have been, but each time the proof that I was wrong has led to new guesses, and I'm afraid to think those guesses may be right."

"I can't begin to guess yet," said Terry.

"You will!" Davis assured him. "You will! You try to add up things.... A half-mile-wide patch of foam that piles up thirty feet above the sea...."

"And into which," Terry interrupted, "a sailing ship does not sink but drops out of sight as if there were a hole in the sea."

Davis turned sharply toward him.

"There were some photographs and a newspaper clipping on the cabin table," explained Terry. "I suspected they might have been put there for me to see."

"Deirdre, perhaps," said Davis. "She's resolved to involve you in this. You've got scruples, so she suspects you of having brains. Yes. You'll add those things up. You'll include the remarkable success of a fishing boat named _La Rubia_ and the fact that she sometimes brings in very strange fish ... And then you'll add ..."

His eyes flickered aloft. A shooting star streaked across one-third of the sky leaving a trail of light behind it. Then it went out.

"You'll even be tempted," said Davis, "to include something like that in your guesses! And then you'll try to come up with a total for the lot. Then you'll be as troubled as I am."

He paused a moment.