“Oh, look, Tom! There’s land!” cried Frank Putney as, coming on deck one beautiful morning, he glanced across the shimmering sea and saw a low cloud-like speck upon the horizon ahead.

“Hurrah! it must be the Bahamas,” exclaimed Tom Pauling, as he saw the first bit of land they had sighted since leaving New York three days previously. “Say, isn’t it bully to see land again? And isn’t this water wonderful?”

To the two boys, the short sea trip had been a constant source of interest, for while they had both been on ocean-going steamships before and Frank had crossed the Atlantic, yet neither had ever visited the tropics. The glistening flying fish which had skittered like miniature sea-planes from under the plunging bows of the ship had filled them with delight; they had fished up bits of the floating yellow sargassum or Gulf Weed and had examined with fascination the innumerable strange crabs, fishes and other creatures that made it their home; they had watched porpoises as they played about the ship and they had even caught a brief glimpse of a sperm whale.

The wonderfully rich indigo-blue water of the Gulf Stream was a revelation to them and now that they were rapidly approaching the outlying cays of the Bahamas, with the surrounding water malachite and turquoise, emerald and sapphire with patches of dazzling purple and streaks of azure they could scarcely believe it real.

“It doesn’t look like water at all,” declared Tom, as his father joined them.

“It looks like—well, like one of those futurist paintings or as if some one had spilled a lot of the brightest blue and green paint he could find and had slapped on a lot of purple for good measure:”

Mr. Pauling laughed. “That’s accurate if not poetical,” he replied, “and you’ll find, when you go ashore, that the imaginary man with the paint pot did not stop at the water. The land is just as gaudy and incredibly bright as the sea.”

“Is that Nassau ahead?” asked Tom.

“No, that’s a small cay,” replied one of the officers who had drawn near the little group, “Egg Cay they call it. We’ll raise Rose Cay next and should sight New Providence and Nassau about two o’clock. Pretty, isn’t it?”

So intensely interested and excited were the two boys that they could scarcely wait to eat their breakfast before they again rushed on deck to find the little islet close to the ship, its cream-colored beaches and purplish-gray coral rocks clear and distinct above the marvelously tinted water edged by a thread of surf and with a few straggling palm trees nodding above the low, dull-green bush which covered the cay.

But to the boys, there were more reasons for being interested and excited than the mere fact that they were gazing for the first time at a tropical island or were about to visit a strange land. They were on an exciting and strange trip, a remarkable mission for two boys and one which promised an abundance of adventure.

Like so many boys, they had become interested in radio and during their experiments with various sets had heard peculiar messages from some unidentified speaker. With their curiosity aroused, they had tried, merely for the fun of the thing, to locate the sending station by means of loop aerials or radio compasses.

Having decided that the voice came from a certain block on the East Side of New York, they had reported their discovery to Mr. Henderson, a federal employee and an associate of Tom’s father, for their boyish imaginations had been fired with the idea that the speaker was a lawbreaker associated with a gang of rum smugglers whom Mr. Pauling was endeavoring to run down. But when a search of the block by Mr. Henderson’s men failed to reveal any trace of a radio outfit the boys had lost interest in the matter.

Then, when Mr. Pauling had returned from a mission to the Bahamas and Cuba, he had told the boys of a young man named Rawlins who had devised a remarkable type of diving suit which required no life line or air hose, the oxygen for the diver to breathe being produced by means of certain chemicals. Mr. Pauling had mentioned that the inventor of the suit had stated that its one fault was that the user could not communicate with those on a ship or on shore and Tom; his mind ever on his favorite hobby, had suggested that radio might be used. Later, when Rawlins met the boys in New York and Tom told him his ideas, the diver fell in with the scheme and declared that he believed it would be feasible to make a radio telephone apparatus which could be used under water.

Fitting up his father’s dock on the East River front as a workshop and laboratory, Rawlins and the boys worked diligently at Tom’s invention and at last succeeded in devising a radio set with which the diver could talk freely and easily with people on shore or with others under the sea.

While trying out the device Tom and Rawlins discovered two other divers whose actions were suspicious, and watching them, were amazed to see the men enter an old disused sewer. Following them into the sewer Tom and his companion were startled at hearing a conversation in some foreign tongue and Rawlins insisted it came from the other divers and that they too possessed undersea radio telephones. Hiding in the shadows the two saw the strangers standing under a trap-door into which they disappeared, taking with them a mysterious, cigar-shaped, metal object like a torpedo.

A little later, as Tom and Rawlins were about to return to their own dock, they again saw the men and following them were thunderstruck to discover that they were about to enter a submarine lying at the bottom of the river. Curious to find out more about the undersea craft, Rawlins approached it and was suddenly attacked by the two men. Tom unconsciously screamed and at the sound Frank, who was anxiously waiting at the receiver on shore, asked what was wrong. Suddenly, realizing that he was in touch with his friends, Tom called for help asking Frank to send for the police. At his cries the submarine quickly got under way, deserting the two strange divers who, seeing their craft had left, surrendered to Rawlins.

In his excitement one of the men had been careless and as a result the chemicals in his suit had flamed up at the touch of water and the man had been seriously injured. With the captured diver, Tom and Rawlins had made their way to the dock, carrying the wounded man and had arrived just as Mr. Pauling with Mr. Henderson and the police arrived. Tom had fainted from strain and excitement and when he recovered consciousness found that the captive had been recognized as a dangerous escaped criminal, a Russian “red” and that the other man was at the point of death.

Mr. Pauling, having heard Rawlins’ tale, suspected a connection between the deserted sewer, the strange divers, the submarine and the mysterious messages the boys had heard and at once sent the police to surround the block and search the buildings. As a result of the raid, a garage had been found with a secret passage connecting with the sewer and in which were stored vast quantities of liquor, contraband goods, Bolshevist propaganda and loot taken from hold-ups and robberies in New York.

Feeling that they had stumbled upon the key to a wave of crime and “red” literature which had been sweeping the country, Mr. Henderson questioned the captive, Smernoff, who confirmed the suspicions and confessed that the submarine had been used for smuggling liquor and other contraband into the united States and taking the ill-gotten loot out and that the contraband had been picked up by the sub-sea boat in mid ocean at spots where it had been dumped overboard from sailing vessels by previous arrangements.

He insisted, however, that he knew nothing of the headquarters of the gang or of their leader whom Henderson and his associates believed was a master criminal, an unscrupulous, fiendish character who, during the war, had undertaken to destroy the Leviathan, Brooklyn Bridge, the Navy Yard and many buildings as well as thousands of people in America and England, but who, failing in this, dared not return to Germany. The government officials felt confident that this same master mind was responsible for the wave of crime, the flood of Bolshevist literature and the threatening letters which had baffled them.

Mr. Pauling and Mr. Henderson were also most anxious to secure a statement from the other man, who was still unconscious in the hospital, and when at last he was able to speak Mr. Pauling hurried to his side. The dying man, thinking that his comrades had betrayed him, related an astounding story, admitted the existence of the master criminal and was on the point of revealing his headquarters when he died.

At almost the same time word was received that the submarine had been picked up, drifting at sea, by a destroyer despatched to find her, but that she was absolutely deserted. When at last she was towed into New York and was examined by Mr. Pauling, Rawlins and the boys she was found stripped of everything which would have thrown light upon the mystery. Questioning the crew of the destroyer, Rawlins discovered that a fishing schooner had been sighted near the drifting submarine and from the description he recognized it as a Bahaman vessel and jumped to the conclusion that the crew of the submarine had transhipped to it.

Believing that he could locate the headquarters of the plotters, Rawlins suggested that he and the boys should go to the West Indies and, after some objections had been overcome, this plan had been agreed to by Tom’s father. Thus it came about that the two boys were now upon a steamer’s deck as she churned her way through the intensely blue sea towards the palm-fringed islands beyond her bows.

“I wonder when Rawlins will get here with that sub,” remarked Mr. Henderson.

“Not for several days yet, I imagine,” replied Mr. Pauling. “There was a lot of work to be done upon her and she cannot make much over fifteen knots on a long cruise. I’m personally more anxious to hear from the destroyers that are chasing the schooner. I wonder if Rawlins was right in his surmise regarding her.”

“We should hear from them soon after we reach Nassau,” declared the other. “We left three days after the destroyers and that schooner certainly could not beat the destroyers to the islands or evade them. I don’t think there’s the least question about their overhauling her.”

“Say, won’t it be great if they do catch her,” exclaimed Tom, “and find the crew of the submarine aboard?”

“Yes, but it’s very evident they have not even sighted her as yet,” replied his father. “If they had we would have received a radio.”

“Perhaps they’re out of range of communication,” suggested Mr. Henderson.

“Oh, no,” Tom assured him. “The operator says all those naval vessels can send for several hundred miles and the weather’s been fine—no static to speak of. We were talking to a Porto Rico liner this morning.”

“I hope you haven’t given away any information in your enthusiasm over radio,” remarked his father. “Remember we don’t want any one—not even ‘Sparks’—to have the least inkling of our purpose or plans Always bear in mind the famous Spanish proverb that ‘a secret between two is God’s secret but a secret between three is everybody’s.’”

“You needn’t worry about us, Dad,” Tom assured him, “we haven’t breathed a word—not even about our under-sea radio, although we were just wild to tell about it. You know our motto is ‘see everything, hear everything and say nothing.’”

“Stick to that and you’ll be a credit to the Service,” laughed his father as he and Mr. Henderson moved away.

Tom and Frank soon forgot all about radio or the chances of the swift destroyers overtaking the schooner in the many interesting sights about: the long-tailed graceful tropical birds whose snowy breasts appeared a delicate sea-green from the sunlight reflected through the clear water by the white sandy bottom of the sea; the bigger Booby gannets that kept pace with the ship, seeming to float without effort just above the rails, and that kept turning their china-blue eyes with a curious stare upon the boys; the big, clumsy pelicans that, in single file, flapped along a few inches above the sea, rising and falling in unison with the waves and now and again plunging suddenly with a tremendous splash into the water as their sharp eyes spied schools of small fish. All these were new and strange to the boys and once they caught a glimpse of a V-shaped line of twinkling red dots against the blue sky which one of the officers assured them was a flock of flamingoes.

“Gosh!” exclaimed Tom suddenly. “Say, just look there, Frank! See, down there between the waves—I’m dead sure I saw the bottom!”

The officer chuckled. “Of course you did!” he assured Tom. “Why not? You can see bottom at ten fathoms down here anywheres. Water’s as clear as glass. Why, when you get to Nassau you can look down and see the sea-fans and corals and marine growths perfectly plainly—sea-gardens the Conchs call ’em—regular places for tourists to go. And you can sit on the dock and fish and watch the fool fishes nibbling at your bait—red and blue and yellow and every color of the rainbow. Then, when you see one that suits your fancy you can just yank him up—great thing this being able to pick your fish!”

The boys looked at him half suspiciously. “Say,” exclaimed Frank, “are you trying to kid us?”

“Not a bit of it,” replied the purser. “Just wait and see. Why, if I told you half the truth about such things you’d swear I was lying.”

“Golly!” ejaculated Tom. “Wouldn’t it be fine to go down in a diving suit in such water. I don’t wonder that R—” Tom checked himself just in time and asked, “But what do you mean by saying the ‘Conchs’ call the places sea gardens?”

The purser laughed. “Oh, I forgot you’d never been down here,” he said. “Conchs is the local name for the Bahamans. Guess it’s because they’re always diving for conchs or maybe because they’re as much at home under water as on land. Greatest divers in the world; fact, I’ve seen ’em diving for sponge and coral many a time and when we get to Nassau this afternoon you’ll see about ten thousand naked nigger boys crowding about, begging you to toss pennies to ’em so they can dive and catch them. Little beggars can grab a coin long before it gets to the bottom and if you toss a penny off one side of the ship they’ll dive off the other, swim under the keel and get the coin before it reaches bottom. And speaking of diving—say, this is the real home and headquarters of that. Met a chap down here last winter—Rawlins is his name—was taking a lot of movies under water, fact. Had a new-fangled sort of suit that didn’t have ropes or hose or anything and just plumped overboard as easy as is and wandered around making friends with the fishes.”

The boys nudged each other and winked. “Oh, now you are kidding us!” said Tom. “How could a fellow go down without air and how could he take movies under the sea? That’s too big even for us to swallow.”

“Fact, just the same,” the other declared. “Had some sort of gadget fixed up on his suit to make air and he took the movies in a big steel room or chamber at the end of a jointed, water-tight pipe—had electric lights and everything in it. Sure thing and no fooling. Saw some of the pictures up in New York too. Yep, one of ’em was called ‘Drowned Gold’ or something of the sort—story of a treasure under the sea—gathered in by Huns in a submarine and cached in an old wreck. Rattling good picture too! Say, you boys want to see his place—got a regular studio here. I don’t think Rawlins is here though.”

“That would be interesting,” agreed Frank, “I’d love to go down in a diving suit and walk about on the bottom. Don’t the fish and things ever trouble him?”

“No,” responded the purser, “even sharks keep off—only danger’s in devil fish—octopus, you know. They grow mighty big hereabouts and are likely to grab anything. Rawlins was making one picture of a whopping big octopus fighting with a diver—fake devil fish made out of rubber, but natural as is. Don’t know how it turned out but I tell you I’m not keen on running foul of any of the real thing. And speaking of sharks—say, here’s a fact that you boys will think’s a whopper. Niggers down here dive in right among the sharks—carry a long knife in their teeth—and grab hold of a shark’s fin and knife him, fact!”

“Well, you can’t tell any yarn bigger than that!” laughed Frank. “Imagine a man tackling a shark under water! Oh come, you must think we’re easy!”

“Well, just wait and see,” replied the purser, “but I’ll have to be running along. There’s New Providence ahead—we’ll be getting into port within the next hour.”

“Gosh, he’s some talker!” exclaimed Tom with a laugh when the loquacious officer had left. “And wasn’t it rich—his telling us about Rawlins and the suits and never guessing we knew him or had been down in those suits ourselves! Say, I’m beginning to think there’s a lot of fun in being Secret Service people. It’s sport listening to folks telling all they know about a thing that you know more about and they never guessing it.”

“Yes,” agreed Frank, “and I can understand now how detectives and Secret Service men find out so much without any one suspecting them. They just start a conversation and then let the other fellows do the talking and pick up a lot of information. But that was rich about the sharks!”

“And the devil fish too!” added Tom. “Wonder if there is any danger from being attacked by an octopus. Say, if there is that’s where our undersea radio would come in mighty fine.”

But whether or not the purser’s tales were true in regard to the sharks and octopus the boys soon discovered that he had not in the least exaggerated the clarity of the water or the skill of the native diving boys when their ship steamed slowly into Nassau harbor.

It was all so wonderfully fascinating and beautiful that the boys kept constantly uttering exclamations of surprise and delight. Never had they dreamed that there could be such vivid colors anywhere in the world. The sky, so blue it resembled a dense solid dome of blue silk; the water, ultramarine, emerald and turquoise streaked with gold and purple; the vivid green foliage with masses of scarlet hibiscus and flaming poinciana trees; the glaring, snow-white coral streets; the pink, blue, green, yellow, and lavender houses with their red roofs and green shutters; the bright-hued orange and red bandannas and gleaming costumes of the negro women crowding the dock; the lofty nodding palm trees above the beaches and looming like gigantic feather dusters above the buildings; the crimson and blue flags of England flying everywhere; the scarlet tunics of strolling soldiers from the garrison; the little shore boats bobbing upon the water and painted every color of the rainbow and scores of sponging and fishing smacks as brilliant in hues as the smaller craft, all combined to form a kaleidoscopic picture of gaudy tints and blazing colors such as can be found only in the tropic islands of the Caribbean. But all these sights were of less interest to Tom and Frank than the naked black, brown and yellow diving boys who paddled about the ship in crude home-made boats, formed from discarded packing cases, or straddled lengths of bamboo and with grinning faces and rolling eyes begged the passengers to throw coins into the water exactly as the purser had described. And when Tom and Frank tossed shining nickels into the sea and the score of black bodies left the makeshift boats as one, the two American boys burst into roars of merriment.

“Gosh, they’re just like a lot of black frogs!” cried Tom. “And just look at them, Frank! See them! Look there! They’re after those nickels and you can see them as plain as if they were under glass! There! Look! One of them’s got a coin! And see how funny the pink soles of their feet look! Say, it’s wonderful!”

For the next half hour the diving boys reaped a rich harvest of small coins and then, the customs and port doctor’s men having completed their inspection, Tom and Frank followed Mr. Pauling down the gangway and a few moments later stood upon the first West Indian island they had ever visited.