The Project Gutenberg eBook, Sign of the Green Arrow, by Roy J. (Roy Judson) Snell

E-text prepared by
Stephen Hutcheson, Rod Crawford, Dave Morgan,
and the Online Distributed Proofreading Team
(http://www.pgdp.net)

A Mystery Story

SIGN OF THE
GREEN ARROW

By
ROY J. SNELL

Reilly & Lee
Chicago

COPYRIGHT 1939
BY
REILLY & LEE
PRINTED IN THE U.S.A.

CONTENTS

CHAPTER PAGE [I “This is Our Secret”] 11 [II Spooky Waters] 22 [III A Bright Eyed Beach-Comber] 34 [IV Spies] 46 [V Whispering Depths] 54 [VI Real Progress!] 73 [VII Mystery Singers of the Night] 82 [VIII Monster of the Deep] 96 [IX Dave’s Electric Gun] 105 [X Little Big-Heads] 115 [XI Tigers of the Sea] 125 [XII Johnny’s Day Off] 136 [XIII The Green Arrow Trail] 150 [XIV An Important Discovery] 161 [XV Adrift in the Depths] 167 [XVI Voice of Drums] 174 [XVII Marching on the Castle] 183 [XVIII The Battle] 192 [XIX On the Bottom] 204

SIGN OF THE GREEN ARROW

CHAPTER I
“THIS IS OUR SECRET.”

It was midnight. Johnny Thompson paced the deck of the Sea Nymph alone. He would be doing this until daybreak. The tropical night was glorious. There was a faint breeze—just enough to ripple the waters where the phosphorescent light thrown off by a million tiny creatures rivaled the stars above.

“Spooky,” he thought, meditatively. “Out here all alone with the night.... Natives over there.” He faced the east, where dark green hills loomed out of the water. Over there was a small island. Johnny never had been there. Some time he’d get into a canoe and paddle over. Earlier in the evening he had seen a light, a white man’s light, he had thought, without knowing why. He—

His thoughts were interrupted by someone moving, up forward. Or was there? He had supposed they all were asleep—the strange old man, bony and tall, with goggle eyes and heavy glasses, the tall young man and the blonde girl. They all had berths forward. The captain and mate were aft; the native crew, below deck. There was no need for any of the crew, now. The boat was anchored. Only he, Johnny Thompson, was needed, to keep watch for prowlers of the sea, or signs of a storm.

It was strange, this new job. He was not sure just what these people were planning—some scientific expedition, he thought. The ship’s outfit was rather irregular, but he had been glad of the chance to sign up as watch. He loved the sea.

“Someone—” he said to himself, “—is moving, up there.” He started forward, cautiously.

He had covered only half the hundred and twenty-five foot length of deck when suddenly he beheld the girl of the party.

“Walking in her sleep,” Johnny thought, with a touch of alarm. But she wasn’t.

“Hello!” She poked a hand from beneath her midnight-blue dressing gown. “It’s too swell a night to sleep.”

“Yes,” Johnny agreed.

“You’re not a regular watch, are you?” she asked.

“That—er—” Johnny hesitated. “That’s not my regular job. Nothing is. Does that matter?”

“No, I suppose not. Anyhow nothing could happen, here.”

“Plenty could happen,” he contradicted, quietly.

“How do you know?”

“I’ve been in the Tropics before. Natives get ugly sometimes. They imagine white men are getting the best of them—which, for the most part, they are!” Johnny laughed. “Then there are storms,” he went on. “Wildest place for storms you’ve ever seen. Once I drifted before a storm for thirty-six hours in a boat just about like this, only—” he hesitated, “it was different.”

“Yes,” the girl laughed, “it must have been, as there’s not another boat quite like this in all the world, I guess. It—

“Look!” she exclaimed softly, pointing toward the distant island. “What’s that strange light?”

“Light?” Johnny spun round. “Oh! Say—that is strange! It’s green. A green light.”

“Like an arrow,” the girl whispered. “Green arrow of the Tropics. Quite romantic! But what can it be?”

“It’s not for us,” said Johnny. “It—it seems to blink. Wait!”

Retracing his steps he went to a box of life-preservers where he had left his heavy field glass. He returned quickly to her side.

“Now,” he invited, “have a look!” He held the glass in position for her.

“It—it does blink,” she murmured. “It’s like an electric sign. Some lights go off; others go on!”

“Let’s see.” Johnny took the glass. “Why—it’s some sort of signalling,” he decided at once. “But not for us!”

Instinctively they turned to scan the sea.

“There’s no other boat out there,” said Johnny. “At least there wasn’t any at sunset. If one had moved in, we’d see the light.”

“If there were a light,” whispered the girl, “how gorgeously mysterious it’d be. How—

“Look!” she exclaimed. “Do you see it? A green arrow out there on the sea?”

“No—oo,” Johnny said, after a moment of gazing. “I can’t see it. Must have been a reflection of that other light. That often happens, you—”

“No!” The girl said, emphatically. “There! I saw it again!”

“Perhaps I’m color-blind,” said Johnny after another long look. “But I just don’t see it!”

At that he turned around to continue his study of that land light.

“It’s strange,” he murmured. “I can’t quite count the lights, but they do go on and off. Irregularly, too. It must be a signal. But what are they saying?”

“And to whom?” the girl added.

“Well,” she sighed a moment later, “we’ll not learn the answer, at least not tonight. Because it’s gone!”

“So it is,” said Johnny, after a long look at the island.

“Sha—shall we tell them?” he asked after a moment.

“Who? Grandfather and Dave? Oh—why should we? It can’t be anything that affects us! Let’s keep it for our own little secret. Perhaps we’ll solve the riddle—”

“All right,” Johnny agreed, readily. There’s a queer girl for you, he was thinking. She’d be lots of fun, though.

“Is the elderly man your grandfather?” he asked.

“Yes. Professor Casper’s his name. Only wish I knew as much as he does. My name’s Doris—Doris Casper.” She put out her hand. “I—I’ll be seeing you. Good night. And don’t forget—it’s our secret—sign of the green arrow!”

She was gone.

“Sign of the green arrow,” Johnny whispered, softly. “Perhaps I should report it to the professor. And then again—perhaps I shouldn’t. It can’t have a thing to do with this boat, and it’s entirely out of my line of duty. The girl wants to share a secret. Most girls do, in fact. So why not?”

With that, for the present at least, the whole affair was dismissed from his mind.

Half an hour later he found himself sitting alone on the after deck, glancing away at those dim, mysterious shores, and thinking back over the events that had led up to this mildly exciting night.

Two months before, he had found himself in New York wanting a job, and not able to find one. After three weeks of trying he had grown somewhat bitter about the whole thing.

“I’m intelligent,” he had said to a prospective employer. “I’ve always worked. I like it. Why shouldn’t I have a chance?”

“Why not?” the grey haired man had replied sadly. “I’ve asked that question often, but I don’t know the answer. I only know we can’t use another man.”

That very afternoon, while watching boats moving out to sea, Johnny had his chance, and took it. He caught sight of a young man, struggling toward a gang-plank under a heavy load.

“Give you a lift?” he had volunteered, courteously.

“Whew! Yes.” The man mopped his brow. “Looking for a dime?”

“Not yet!” Reddening, Johnny impulsively jerked a few small bills from his pocket. “Not broke, yet.”

“Oh!” The man looked at him with interest. “Say!” he exclaimed. “I shouldn’t wonder if you’d do!”

“For what?” the boy asked.

“I’m off to the Spanish Main to take pictures—native life, ancient ruins, and all that. There’s a lot of stuff to lug, and—” he hesitated, “perhaps a fight to step into now and then! Want to go?”

“Do I?” Johnny grabbed the two largest bags.

“There’s no money in it! Just experience and expenses.”

“All right! What are we waiting for?” Johnny led the way up the gang-plank.

All that had been two months before and what wonderful months those had been! Sailing from island to island, they had taken pictures of quaint, native homes, of native women with flashing eyes, of ancient buccaneer cannon, fast rusting to nothingness. There had been three exciting fights, with men who had thought they were intruding. In one of these, a machete had come within a fraction of an inch of Johnny’s ear. He seemed to feel the cool swish of it now.

Then, he thought with a sigh, those golden days had ended. Lee Martin, the photographer, had been called back to New York.

“You keep the stuff,” Lee had said to Johnny. “You may be able to get some unusual pictures. If you do—send ’em home to me. I’ll see what I can make out of ’em, for you.”

Johnny had watched Lee’s boat fade into the distance. Then, with heavy heart, he had marched back to his lodgings in Port au Prince, the capital of the Island Republic of Haiti.

That very day he had noticed the Sea Nymph, located the man in charge, and signed up as watch. His photographic equipment was in his stateroom. He had laid in a good supply of film packs and plates. Would he find opportunity to use them? Would he get some unusual pictures to send to Lee Martin? Time was to answer all these questions in its own way....

“It’s a strange layout,” he thought, as he took a turn about the deck. “I suppose I’ll know what it’s all about before long.”

It was indeed a strangely equipped craft. A three-master, with an auxiliary motor for bad weather, the Sea Nymph had been built for island trade. Since the bottom had dropped out of the sugar market, she had been lying idle in the harbor. Without making many changes, the elderly professor had equipped her for his purpose, whatever that might be. Johnny had not yet been told. There had been a hold at the boat’s center, for sugar and other freight. This had been transformed into a tank—or swimming pool. Johnny could not tell which. Doris, garbed in a gay swim suit, had taken a morning plunge there, but he had a notion it was for some other purpose, also.

Strangest of all, close to the stern where it could be reached by the stout hoists, was a large, hollow steel ball. It was all of eight feet in diameter, and its walls were several inches thick. What, he had asked himself more than once, could that be for? But he had asked no one else. The natives would not know, and one simply did not ask such questions of an employer. Besides, Johnny had learned long before, it is a waste of time to ask questions which, in good time, will answer themselves....

CHAPTER II
SPOOKY WATERS

Johnny’s questions regarding the steel ball were answered the following afternoon. After his usual six hours of sleep, he was sitting on the deck when the young man they called Dave—his whole name was Dave Darnell—approached him.

“I saw you taking pictures yesterday,” Dave said with a smile.

“Yes,” Johnny answered. “Just a picture of that island. I hope you didn’t mind.”

“Not at all”, said Dave. “That looked like a rather good camera.”

“It is!” Johnny exclaimed. “None better. Of course,” he added, grinning, “it’s not mine. It was loaned to me. And there’s equipment, screens for infra-red pictures, flash bulbs, flood-lights—about everything.”

“Say—ee—” Dave exclaimed. “Looks like you’re a real find! Want to go down and try your luck at taking pictures?” He nodded toward the big steel ball.

“Down?” Johnny asked, a little blankly.

“Yes—to the place of eternal night!”

“E—eternal night!”

“That’s right! I can’t describe it to you! But I can show you. Question is—can you take pictures in complete darkness?”

“They don’t come too dark for me!” Johnny flashed back. “Lee Martin and I took a picture of a Voodoo witches’ meeting—people hiding in the dark from the island police. You couldn’t see your hand. But we got the picture all right. And I nearly lost an ear! A burly black fellow swung at me with a machete!”

“Nothing like that down there,” Dave chuckled. “All the same—you’ll be surprised! Do you want to go?”

“Sure—I’ll go,” Johnny agreed. “Only,” he hesitated, “I have a strange horror of being completely out of touch with the rest of the world! What do we do about that?”

“That’s easy!” Dave laughed. “We have a short-wave set on the boat and another in the steel ball. Doris or the professor is always listening in. How about it—do we go?”

“We sure do!” Johnny grinned.

“O.K.! Get your stuff together. We’ll go down in an hour!”

“Wonder what I’m getting into now?” Johnny asked himself as he walked to his stateroom.

An hour later he found himself passing through one of the strangest experiences of his life. He was seated, doubled up. Had he wanted to stand, he could not have done so. His eyes were wide open, but he saw never a thing!

“Inky black!” he whispered.

“Nowhere else will you see such darkness,” came Dave’s voice, close at his side.

“But look! There’s something!” Johnny exclaimed in a low tone.

“Yes!” Dave’s voice rose excitedly. “And it’s something quite new!”

Johnny stared with all possible intensity. Before him—how far away he could not tell—there moved a series of small, round spots of yellow light. “It’s like flying through the air at night,” he murmured; “and seeing the lights of a huge Zeppelin passing.”

“Quick! Get your camera ready!” said Dave.

“All right—it’s all set!” Johnny’s own voice sounded strange to him.

“I’ll turn on the light,” said Dave. “Now!”

“One, two, three—” Johnny counted to ten, and closed the camera shutter with a click.

“Now! One more picture,” urged Dave. Another click. “They’re passing. They’ll soon be gone. If only it works!” Dave’s voice grew louder with excitement.

“There”, Johnny sighed. “That’s two pictures—I hope!”

“No time for another,” said Dave.

Johnny stared once more at the blue-black darkness before him, and marveled afresh. Could anything be stranger than this? Queerest of all—there had not been one ray of visible light. And Dave’s voice at his side had said, “I’ll turn on the light!”

But Johnny knew what it was all about. He had taken pictures in the dark before. Still the strangeness of it all, baffled him.

As if brought on by the darkness and mystery, he suddenly thought of something he must tell Dave.

“Samatan is stirring up trouble with the crew of the Sea Nymph!” he said.

“Our cook? Samatan?” Dave’s voice registered surprise. “You must be mistaken.”

“No” said Johnny. “I heard him last night”.

“But why should he? He is well paid.”

“That’s what I don’t know.” There was a note of perplexity in Johnny’s voice. “It’s what somebody must find out. What if he should persuade the men to hoist anchor and sail, right now?”

“Right now?”

“Yes.”

“That would be practically fatal! It—

“But look!” Dave’s voice changed. “There they are again! I never saw such a sight! Get ready for another picture!”

Johnny quickly took another picture—two—three more pictures. After that, the spots of yellow light disappeared as before, and—for what seemed a very long time—there was nothing but inky blackness.

Johnny settled back for a few, fleeting thoughts. That he was due for some unusual experiences he had never a doubt. Fancy, going far beneath the surface of the sea in a thing like this steel ball! Suppose something went wrong—even the least little thing! What then? Dave had told him it was possible to go down half a mile, perhaps more. Would they ask him to go down that far to take pictures?

Sometimes, he thought, it’s better not to know too much about what is ahead.

He had been vastly interested in their manner of taking off in that steel ball. They had crawled through a small entrance in the side, and taken their places. Then had come the bang of a steel door, swung into place. This was followed by the clang of wrenches, bolting them inside!

Dave had seen him move, restlessly. “Don’t let that bother you,” he had laughed. “I’ve been down scores of times. It—it’s just grand! Professor Casper got the thing up,” Dave had explained. “Now his doctor won’t let him go down—on account of a bad heart. So it’s up to me, on this trip. There are things we want to know. Your pictures should help.”

There hadn’t been time for any more talk. After the door had been securely bolted down, the hoist had lifted them over the rail and lowered them gently into the inky depths.

With a suddenness that was startling, Johnny awoke from his revery. Like the flash of electric bulbs, lights were appearing and disappearing before his eyes.

“Wha—what is it?” he exclaimed.

“Shrimp,” was Dave’s matter-of-fact reply. “Something is after them. The squid shoots out ink to make himself invisible, but in this darkness that would do no good. These shrimp shoot out little balls of fire. Look!” Suddenly Dave switched on a powerful electric light, and the little world about them was transformed.

Seeming to swim in air, a score of tiny, crab-like creatures moved rapidly across the spot of light. Viewed through the six-inch-thick window of fused quartz, they seemed fantastic indeed.

For a few seconds the space before them was a dark and empty void. Then again, it filled with darting creatures. Dave switched off the light, and once again the shrimp disappeared. As soon as the more powerful light from their strange, sub-sea visitor had been turned on, they had appeared as dark, darting creatures.

“What was following them?” Johnny asked.

“Who knows?” There was a suggestion of deep mystery in his companion’s tone. “That’s the thrill and charm that comes from exploring the sea’s depths! Anything may put in an appearance. Creatures such as the world never has dreamed of, may pass before our eyes!”

“How strange! How sort of—”

Johnny broke off to stare, then to exclaim—“There—there’s something huge!”

“Quick! The camera!” Dave’s voice trembled. “No—it’s too late!”

Moving with surprising swiftness, some great, dark bulk passed through the outer edge of their narrow beam of light.

“Wha—what was it?” Johnny felt a little giddy.

“Some huge creature of the deep. Perhaps a whale or a black fish,” Dave replied quietly. “It is known that they penetrate to these depths. Then again—perhaps it was some huge, scaly creature that inhabits these depths alone.”

“What if it had collided with us, or tangled in our cable?”

“Then,” Dave’s tone was dry and droll, “we might have taken a long, swift ride through space!”

“Swinging like a pendulum?”

“That’s it! On our thousands of feet of cable.”

“I shouldn’t like that,” Johnny shuddered.

“Then why bring it up?” Dave chuckled.

“Why, indeed!” Johnny laughed—

After another half hour of waiting, for one more fascinating spectacle, Dave decided to signal for their return to the top. Johnny experienced a real sense of relief.

“To explore the depths of the sea—earth’s last great frontier—this is our purpose,” Dave said, as they began to rise. “For centuries men have been discovering strange creatures washed up on beaches. They could have come from nowhere save the ocean depths. For many years they have been dragging these depths with nets, to discover, if they could, what lived in these ‘spooky waters’ of dense darkness.”

And now, Johnny thought exultantly, I am having a part in an expedition that may reveal the secrets of these dark depths.

But once again his mind returned to Samatan. This strange person, with his apparent hold on the native crew, was cook for the expedition. And a marvelous cook he was. Johnny had been interested in the strange old man, from the first. He had studied him carefully. And there could be no mistake about it—Samatan was endeavoring to stir the crew to something....

Now the blue-black world about him appeared to be changing color. The blackness was less intense.

“It’s like the coming of dawn,” he said to Dave.

“Yes,” Dave chuckled, “only here we may make our own dawn, slow or fast, as we choose!”

That this was to be rather a fast dawn, Johnny was not long in discovering. But it was fascinating. To pass from inky blackness to dark, deep blue, on into colors that resembled a sunrise, and then to the eternal blue of a bright, tropical day, was an experience not soon to be forgotten. From time to time as they rose, strange denizens of the sea seemed to peer at them. Once a shark shot past, and just before they reached the top, a great turtle swam awkwardly away.

Came the bump—bump of their steel ball as, lifted by the great crane, it landed on the deck. Then, almost before he knew it, Johnny thrust his head into bracing fresh air, to be greeted by a smiling face and to hear a girl’s voice saying:

“Hello, Johnny Thompson! How do you like being down in Davey Jones’ locker?”

After assuring her of his enthusiasm, Johnny hurried to his stateroom. He was wondering whether Doris remembered their “secret” of the night before.

CHAPTER III
A BRIGHT EYED BEACH-COMBER

Johnny went at once to a darkroom that had been quickly prepared in the hold. Pictures could be taken on land in what appeared to be complete darkness; he knew this from his work with Lee Martin. But would the utter blackness beneath the sea be the same? He would know, soon.

He watched the films with absorbed interest. As the developer took hold, he saw nothing but blackness.

“Nothing there!” he muttered disappointedly. “Wasted shots. We—”

But wait! Was something coming out? Yes! There it was! An indistinct, shadowy form!

His thoughts leaped ahead. His pictures were to be a success. He would be asked, times without number, to go down in that darkness and take more pictures. Dangerous work, but he had to be a good sport, and besides, it was splendid experience for him.

The strange, undersea creatures, some very large, with heads as long as their bodies, with fantastic buck teeth and hideous eyes, some small and snakelike and some as normal looking as any fish to be found near the surface, came out clearly visible on the film.

“Perfect!” was the professor’s enthusiastic reaction when Johnny showed him damp prints a few hours later. “A real contribution! And you took them in complete darkness!”

“In what appeared to be complete darkness,” Johnny corrected. “I did it with an infra-red light screen. That screen shuts out all but the infra-red rays. Eyes can’t see the light of these rays.

“Of course,” he went on, “we might have used a flood light, but that would have frightened those creatures away. As it is, we got them in what you might call a natural pose. Candid camera shots from the deep sea,” he laughed.

“Yes, yes,” the professor agreed. “Very remarkable and most useful!”

“Of course,” said Johnny, with a touch of modesty. “I learned all this from Lee Martin. He took me on as a helper and sort of body-guard. I just absorbed this camera stuff as we went along.”

“I see,” said the professor, “that you have learned one of the real secrets of success.”

“What’s that?” Johnny asked.

“To learn all you can about everything that comes your way, and to file that knowledge away in your brain. One never can tell when the opportunity to use such information may come to him. Perhaps never, but it’s always there!

“You should be a great aid to us,” the professor added thoughtfully. “You see,” he said, leaning forward in his chair, “I regard this work as the most interesting and exciting of my entire career. Young man,”—his eyes fairly shone, “what place do you think of as our last frontier?”

Then, before Johnny could reply—“You may go east, west, north, south” the professor continued “but you find no frontier. You must go up or down! Up into the stratosphere—or down, into the sea. These are our last frontiers. Dave and I have chosen the deep sea, because there we may yet discover forms of life not known to man. These pictures,” he held them up, “show two types of fish never before seen—and we have but begun!”

* * * * * * * *

“We have but begun,” Johnny repeated softly to himself as, some hours later, he once more paced the deck in his solitary vigil. “We have begun. Where shall we end? We—”

His soliloquy was interrupted. Had he caught a gleam out there on the water? He thought so. Now it was gone.

That was one thing he was to watch for—natives in dugouts and canoes. Who could tell what they might do? In a strange land one did well to keep close watch. He would keep an eye out for that light....

“Exploring our last frontier,” he whispered softly. He was in for something truly big again. Big, exciting, and dangerous! Well, that was the life. Life, action, thrills—and a touch of romance! Boy-oh-boy! That was the stuff!

But there was a gleam of light on the water! There could be no mistaking it. It was closer, too. What should he do? Call someone? After a moment’s thought he decided to wait. His flashlight would reach out a hundred feet or more. Time enough when those people, whoever they were, came within reach of his light. So, somewhat excited, Johnny waited by the gunwale, watching the bobbing of a tiny light—now here—now there—now gone—but ever coming nearer.

He waited, breathless, tense, expectant, watching for some craft. What would he see? Dark faces? Gleaming spears? Flashing machetes? Soon he would know.

When at last he cast the gleam of his powerful light on the spot where that golden glow had last shown, he gasped in astonishment.

“A girl!” he exclaimed, amazedly.

Yes, it was a girl. In a dugout patterned after a white man’s canoe, she came straight on, without a sound. Her boy’s shirt and blue slacks were faded, but clean. Her reddish-golden hair fairly gleamed in the light. She had a round, freckled face and smiling eyes.

As she came alongside, Johnny reached over, took her line and made it fast. Then he gripped her small, firm hand and helped her over the low rail.

“I—I had to come,” she breathed. “I—I’ve been watching you for days. What—” there was tense eagerness in her voice, “what is that big ball you let down into the sea?”

“That,” said Johnny, after bringing her a deck chair, “is for going down, down, down, to the bottom of the sea!”

“I—I hoped it would be.”

“Why”

“Our trading schooner, the Swallow, sank. We—we can’t find it. I thought—”

“Thought these people might find it for you?”

“Yes! Yes—that’s it! Do you suppose—”

“I can’t tell about that. You see,” Johnny hesitated, “I’m only a watch, on this boat. I—well you might say I’m just a tropical tramp!”

“That,” said the girl, putting out her hand, “makes us kin! Grandfather and I are beach-combers!

“You see,” she went on, after giving Johnny’s hand a quick grip, “I sort of ran away from home. No, not quite that. I was half through college. It cost an awful lot. My folks couldn’t afford it, but they wanted me to finish anyway. I wouldn’t let them spend the money, so I asked grandfather to send me a steamship ticket. He did—and here I am! It’s grand! Really gorgeous! These nights.” She spread her arms wide. “The jungle! The water rushing along the shore, the birds, the flowers, romance, adventure, everything! It’s just grand!” Her face fairly shone.

“But our boat,” her voice dropped, “sprang a leak in a storm. The natives were sailing her. They lost the location and we can’t find it. Perhaps—”

“You’d have to see Dave,” said Johnny.

“He’s the young man who goes down in the steel ball? I—I’ve been watching you through the glass.”

“Yes, that’s Dave. He takes his work of exploring the sea’s depths very serenely! Tell you what!” Johnny exclaimed. “You get him to take you down!”

“In—in that thing?” The girl drew in her breath sharply, eyeing the distant shadow of the huge sphere.

“Sure, in the steel ball! He’d like to! He’s proud of it. And he likes showing people strange things. If you want someone to do a certain thing for you—ask him to do something else, first! That’s a grand rule.” Johnny looked into the girl’s frank, grey eyes, and decided he liked her.

“Yes—I—I suppose so,” the girl replied, slowly. “But you know—well, anyway—it’s worth thinking about!”

“Look!” said Johnny, starting up. “Perhaps you can tell me what that is.” He pointed to the distant island, where again the blinking green arrow could be seen.

“No, I—” The girl sat there, staring. “I never saw that before. But you know,” her voice dropped to a whisper, “there are spies on these islands! Lots of spies!”

“Spies?” Johnny’s voice expressed astonishment.

“European spies,” she added.

“But why?”

“I don’t know about it. Grandfather can tell you all there is to know. He’s always talking spies, and saying what they’ll do when the time comes.... You must come over and see us. Our place is just over there on the shore. You’ll come, won’t you?”

“Yes. Certainly I’ll come.”

“Thanks a lot.” Once more she gripped his hand. “And now—goodnight. I—I’m glad I came.” She was over the side and away.

“Well, I’ll be!” said Johnny as he settled back in his chair. A moment later, faint, and far away, he heard her voice come over the dark water:

“My name is Mildred Kennedy. Be sure to come see us—don’t forget!”

For answer Johnny whistled once, cupping his lips with his hands, to reduce the likelihood of arousing anyone on board. After that he was left to silence and the night—and the mysterious arrow of green light, blinking away on the distant hillside.

Sliding out the field glass, he studied that arrow for two full minutes. He felt sure from its strange blinking and winking that it was being used as a code signal. For the life of him, however, he could not make the lights separate themselves. They always remained a blur.

“Too far away,” he grumbled. He wanted to hoist anchor and let the boat drift closer to shore, but this, he knew, would not do. He was neither skipper nor mate.

Suddenly recalling Doris’ words of the previous night, he realized that he had made the light, the secret of the bright-eyed little Mildred Kennedy! “I won’t tell Doris about that!” he decided. “At least, not yet.”

He was seized with a sudden desire to know who was receiving those blinking signals of the green arrow. Deep in thought, he turned his back to the island and, to his utter astonishment, saw above the motionless sea some distance away, a second blinking green arrow!

“Ah!” he breathed, lifting the glass to his eyes. Digging into a pocket, he dragged out a pencil and a small notebook. After that, for fully ten minutes, he held the glass with his left hand while setting down numbers. 5 - 7 - 11 - 9, 13 - 6 - 3, 4 - 9 - 2 - 7. He wrote down figures and more figures, until a strange, rushing sound reached his ears.

Startled, he sprang to his feet. On the shore side he saw a broad band of white foam rapidly approaching the boat. Standing there, mouth open and staring, he watched it sweep toward him. With a hissing roar it swept beneath the boat and, without causing the least movement of the craft, went rushing on.

“False alarm,” he murmured. “Probably what they call a rip-tide.”

Turning back to sea, he looked again for the blinking green arrow. But it was gone. The distant island hill, too, now was entirely dark.

“Strange,” he muttered, as again he paced the deck.

And indeed it was strange, for the ship’s log had recorded no boat in sight at sundown!

From then, until Johnny’s vigil ended with the dawn, there was nothing to disturb the calm stillness of the tropic night.

CHAPTER IV
SPIES

On board the Sea Nymph was a small boat known as the Tub. Very short and broad, it rowed like a washtub, and in a storm, would have been about as safe as a laundry basket. But water held no terrors for Johnny, so, late the following afternoon, he pushed the Tub into the sea and headed for shore.

“You came! How grand!” Mildred Kennedy came racing down a palm-lined path to greet him.

She wore an orange-colored smock, and there was flour on the hand she held out in greeting.

“I’m making cookies,” she confided.

“Sounds great!” Johnny grinned.

She led him to a broad, screened porch where a bearded giant unwound himself from a deep, comfortable chair to meet him.

“This is grandfather.” Real pride shone in the girl’s eyes. “He’s been a beach-comber for thirty years. That’s a record!”

“Now, child,” the old man drawled, “don’t you go bragging on me.

“Have a chair,” he directed Johnny.

“My cookies will burn. I’ll have to hurry,” said the girl. “Grandfather—you tell him about those spies.”

“Spies? Oh, yes. Those European fellows.” The old man’s face darkened. “I’ve been preaching against ’em for mighty nigh twenty years. Mebbe longer than that, I reckon. You see, Mr. Thompson—”

“Please call me Johnny,” said the boy. “I’m not used to the ‘Mister’.”

“All right, Johnny. That’s what it shall be. You see, Johnny, these islands were once a French colony. The French made slaves of the natives. They brought in a lot more slaves and before long, there were many more slaves than there were Frenchmen. So the natives polished up their machetes, started poundin’ their Voodoo drums, and drove the Frenchmen off the islands. This has been a republic ever since.

“But spies, now,” his voice dropped. “How’d you get to thinkin’ o’ spies?”

“Your granddaughter told me there were spies. And there’s been a green arrow—an arrow of light—on the hill at night, and another on the water. It’s sort of mysterious.”

“A green arrow of light,” the old man repeated. “That’s what Mildred was telling me. Strange that I never saw it.”

“You couldn’t,” said Johnny, “unless you were on the water. It’s near the middle of the island, and up high.”

“There’s a place up there built of stone, half castle—half prison,” Kennedy said, thoughtfully. “Some Frenchman built it, thinking he could hold out against the natives. Well, he couldn’t, and now the natives think it’s haunted. Won’t go near it. It’s a long way up a terrible trail.

“But those spies, now,” he added thoughtfully. “They may be using it for a hideout and signal tower. They stop at nothing.”

The old man rose, circled the porch like a prowling tiger, then returned to his seat.

“These natives,” he went on, “are a simple people. They can’t run a country. They found it out soon enough. So did these other people, these Europeans. I won’t name the country as you’ll learn it soon enough. Those Europeans came here and began boring in, just as they do everywhere. You’ll find them in every South American republic and every island of the sea. They’re robbers, spies, traitors!” His voice rose. “They rob the people, and at the same time plot the overthrow of all governments but their own.

“Young man!” Mr. Kennedy left his chair with surprising vigor. “Did you ever take a good look at the map, and think how important this Caribbean Sea is?”

“No, I—”

“Come here. Have a look!”

They stood before a large wall map. “Look at it,” Kennedy insisted. “Plentiful islands with Central America on the west. A score of wonderful harbors. Suppose those people took possession of these islands. Look at Haiti! A harbor where an entire navy might drop anchor! Yes—and room left for ten thousand seaplanes! Bombers! How would our Atlantic coast—Miami, Charleston, New York, Boston—how would they look, after those planes had been raiding from this base for a week, if there were war. And who says there won’t be!

“You saw a light on the water!” He whirled around.

“Yes! Low down! A green arrow of lights, that flashed.”

“‘Low down’!—I should say they were!” The old man grimaced. “Spies!” he muttered. “Since our Marines left the islands—we took control during the World War, you know—these islands have been nests of spies! Something should be done about it. But these natives sleep on—and Uncle Sam doesn’t care to interfere. And yet I’m beginning to hope he will—before it is too late!” His words trailed off as he resumed his seat.

“These people may call themselves beach-combers,” Johnny thought to himself. “Perhaps they are, in a way! But they’re grand folks.”

The house, which he presumed had been built with native labor, was made of massive, hardwood logs. There was no glass in the broad windows, but bamboo “screens,” which could be let down at night. Mosquito-net canopies were hung over the beds to keep out insects. Most tropical houses are like that.

Behind the house were orchards—grapefruit, oranges, bananas. And down in the flat land by the shore, sugar cane was growing.

“We cut it out of the wilderness, the natives and I,” the old man rumbled, in response to Johnny’s polite inquiry. “They’re quite wonderful, these natives—once you come to understand them.

“Of course,” his brow darkened, “some of them can’t be trusted. Those men, those Europeans—” his tone was bitter, “have corrupted them. Yes, and robbed them, too! They pay little for their produce, wild rubber, chicle, wild coffee. And they charge the natives high prices for cheap goods. They get the people deeply in debt to them, and then make slaves of them.

“That,” he sighed, “was why we bought a trading schooner, Mildred and I. We wanted to give the people of our small island a chance. We were doing it, too!” He struck the table a blow with his massive fist. “By George! We were doing it!

“But our boat’s on the bottom now!” His voice fell. “Our natives took her out in a storm, and she sprang a leak.”

“Yes, I know. Mildred told me.” Johnny was wondering whether some treacherous native, inspired by the Europeans, had let the water into the Kennedy boat. At the same time he was making a resolve to do all he could to find the boat and help bring it to the surface.

Mildred entered with a great plate of cookies and a pitcher of ice-cold, fruit juice.

“I hope you like them,” she smiled.

Johnny did like them. What was more, as the moments passed he became more and more interested in his new-found friends. They were, he told himself, good, kind, intelligent people—his kind. They would do things, together. He saw himself with the girl, following obscure trails in search of that spy castle whence, perhaps, the green arrow messages came.

“Well,” he sighed at last, “I’ll have to be getting back. It’s been grand, this visit. I hope you’ll let me come back, and that—that we can do things together.” He was looking at the girl.

“Do things? What, for instance?” Her face was serious.

“Lots of things. Things that may help.” He gave her a broad smile. Then—“just a big batch of day-dreams, I guess.”

At that he shook hands with the old man, walked down the broad path with the girl, gripped her hand for an instant, then climbed into his Tub and rowed away.

“Thanks for one grand time,” he called back.

“You’re welcome, and thanks for coming,” was Mildred’s answer. And the hills echoed back, “thanks—thanks.”

CHAPTER V
WHISPERING DEPTHS

Johnny had an active mind. Figuring and planning were almost continuous activities with him. Sometimes he really tried to slow the process up, but his mind would keep right on, figuring and planning.

As he rowed slowly back to the boat, his thoughts were particularly active. There were things to be done. He would see that they were done, in the end; he surely would. By going down in the steel ball as many times as Dave wanted him to, and by taking pictures, he’d put Dave in debt to him. Then he’d persuade Mildred to go down in the steel ball. Dave would like that. Then, at just the right time, he and Mildred would ask Dave to help find that trading boat at the bottom of the sea, and to float it once more.

Then they would get busy on those spies, he and Mildred and—and anyone else who would help. It was a patriotic duty, by thunder! It surely was! In his mind’s eye he saw the map of the Caribbean Sea, these islands at one side, the Panama Canal on the other. If the Europeans got these islands, what would happen to the canal? Filled with rocks and mud—that was the answer! They’d bomb the very daylights out of it. Yes, they must uncover those spies—at least some of them. He wondered whether the green arrow would show tonight, and whether he would be able to make any sense out of the numbers he had written down in his notebook.

“It’s some sort of code,” he told himself repeatedly. “If I can decipher it we may get somewhere.”

But here he was alongside the Sea Nymph, and Dave was saying:

“Hello, Johnny. We’re shifting our position tonight—coming in a little closer. Tomorrow afternoon I’d like you to go down with me to get some pictures. You won’t mind, will you?”

That was exactly what Johnny had planned. “No, I won’t mind,” he said, “that will be keen.”

A mist drifted out over the ocean. All that night Johnny paced the deck in a chill fog. No green light showed from the island hills. Once he thought he heard men’s voices, but nothing came of it. He was glad enough when he could crawl into his berth, draw his blankets over him, and lose himself in sleep.

When he awoke the sun was shining. It was mid-afternoon, and Dave was waiting for him to appear, for their trip below.

“What a life!” he murmured. After he had gulped some hot coffee, hurriedly bolted some seabiscuits and a piece of pie he reappeared on deck.

“All ready?” Dave asked.

“Soon as I get my camera and things.”

“Good! I’ll have the steel ball in shape P.D.Q.,” Dave grinned, good-naturedly.

“He’s really a nice chap,” Johnny thought. “Only he takes science and discovery pretty seriously. I suppose we’ll discover some saber-toothed viper fish, or maybe some flying snails!” He smiled at his thoughts. Life was not half bad after all.

Half an hour later he was experiencing such thrills as only the deep, deep sea could bring. Some five hundred feet beneath the surface of the sea he sat doubled up in his place, staring at an ever changing panorama. A rocky wall, not twenty feet from him, stood up like a sky-scraper, straight and tall. Here and there it was broken by fissures and caves. Everywhere it was festooned with sea vegetation—seaweed, kelp, anemones. All these, with coral that rose like Gothic architecture, were entrancing.

Dave was by his side—not to admire, but to record. The look on his face was almost solemn. As they moved slowly downward Dave spoke into a small microphone and Doris, up on deck, recorded his words. Strange words they were, too: “A school of parrot fish; three hatchet fish; two round-mouths; a golden-tailed serpent dragon; a—oh—oh!—Hold everything!”

At that instant Dave’s window was opposite a dark cavern. As he threw on a more powerful light he caught the gleam of two, great eyes. How far apart they were!

Despite his efforts to remain calm, Johnny’s heart skipped a beat as, at Dave’s command, he touched his moving-picture camera and set it recording. What sort of creature was this? A whale? A blackfish? Or some strange, unknown denizen of the deep? Suppose at this instant it should become enraged, should rush out of its hiding place and drag the steel ball out into the deep—to send it crashing against the rocky wall? A broken window would mean instant death. And yet Johnny’s hand did not tremble as he adjusted his camera....

Just after the steel ball had gone over the side, Mildred Kennedy, in her dugout canoe, had arrived for a visit. It had called for real courage, this little journey. From a distance these Sea Nymph people had seemed so serious. All but Johnny. “But it’s not decent to stay away and not be properly sociable,” she had told her grandfather. So here she was.

There had been time only for a brief word of welcome from Doris. After that, whispering excitedly—“Dave and Johnny are below in the steel ball. It—it’s dreadfully thrilling, even here on deck,” Doris had clamped a pair of head-phones over her guest’s ears and had whispered tensely:

“Listen!”

So they were seated on the deck of the Sea Nymph, listening intently for reports from below. At the same time, they talked.

“I came to visit my grandfather,” Mildred said, “just as sort of a lark. I was storm bound indoors for two weeks, and when I saw how simple and kind the natives were, the happy, free life they lived, and yet how many things could be done for them, I wanted to stay. So I just did. And I am glad. Only—” A shadow passed over her face.

“Listen!” Doris held up a finger. “Thought I heard a whisper. It—it couldn’t be Dave! I—I hope nothing has gone wrong. It’s truly dangerous being down there, and yet one does learn so much—”

“Shish!” Mildred held up a finger. “I—listen—I hear a whisper! It—it’s numbers he’s saying. How strange!”

As the two girls sat in silence, pressing the phones to their ears, listening with their every sense, they caught—in a low whisper: