As he gained the side and peered over, he gave vent to what was almost ashout of triumph. He had solved part of the riddle at any rate. After apause in the signaling from the stranger, there had come from the sideof the _Tropic Queen_ a sudden flash of red light. It was reflectedruddily on the smooth water as it gleamed across the sea.

  "So that's it, eh, Mr. Jarrold!" cried Jack in a low undertone. "You'vegot some sort of a flash lantern rigged in your stateroom, connectedwith the electric light socket, likely, and you're having a nice littletalk with your friends over yonder."

  All at once he slapped his thigh as a thought struck him. He knew that acommon switch controlled the lights in each separate corridor of theship. Thus, the four cabins in the section that Jarrold occupied, whilethey each had their individual light switches, were also controlled by aswitch in the main corridor.

  This was so that, in case of accident, the electricians could work moreconveniently.

  "I don't know what the skipper would say to this," exclaimed Jack, "buthere goes."

  He darted below and soon reached the point in the main port corridorfrom which the passage on which the four cabins in Jarrold's sectionopened. He fumbled for the switch in the half darkness. First, though,he had looked to see that no other lights were shining in that sectionexcept the one he was sure was being used in Jarrold's room.

  Click! The switch was turned.

  "Now we'll see," exclaimed Jack to himself.

  He hastened back on deck. Through the night, off to the port the strangecraft was signaling frantically. Jack chuckled.

  "Spiked your guns, Mister Jarrold," he laughed, as the signalingcontinued. Plainly on the other ship they could not understand why theyno longer got flashed replies from Jarrold's room.

  "Oh, I'll bet the air is blue below," chuckled Jack, delighted at thesuccess of his plan. "Now I'll just watch till they get sick of waitingfor Mr. Jarrold, and then go below and put that switch on again."

  For half an hour the vain red flashes came out of the night and thenthey ceased.

  "I guess they've sneaked off for fear daylight would discover them,"said Jack. "Now to switch the light on again, and then for a snooze. Ithink I've earned it."

  CHAPTER XVI

  S. O. S.

  Dawn showed a smudge of black smoke on the far horizon which might ormight not have been the mysterious visitant of the night. At any rate,by noon something occurred which quite put out of Jack's mind, and thoseof the ship's officers, who were considerably exercised over themidnight signals, all thoughts of the secretive craft.

  To Jack, seated at his instruments, there had suddenly come a sharpcall:

  "S.O.S.--S.O.S.--S.O.S."

  Coming as it did, like a bolt from the blue, the urgent call thrilledthe young operator. He galvanized into action instantly and sent Samscurrying to the bridge with word that the most urgent call that canassail a wireless man's ears had just come to him.

  It was faint and far away, but that very fact made it evident to Jack'sexperienced mind that whoever was sending the message, was in direstraits and running out of current.

  He pressed his key and sent thundering out with all the volleying forceof his powerful dynamos, an answer.

  "What ship are you?" he demanded.

  The answer that came back almost knocked him out of his chair.

  "The airship _Adventurer_, from New Orleans to Havana. We are on thesurface of the water and sinking rapidly."

  "Your position, quick!" demanded Jack.

  Back through space, in a slowly dying wireless voice, came the latitudeand longitude of the luckless craft.

  "You are on our course. Stand by and we will pick you up," said Jack,whom a rapid glance at the wall map had shown that, roughly, the sinkingair-craft was not more than twenty miles to the southwest of the _TropicQueen's_ position.

  "What has happened?" asked Jack.

  "No time explain details. Hurry! Hurry!----"

  Jack tried to get the unseen operator once more, but a silence that wasfar more eloquent than words alone greeted his efforts. He turned to seethe captain, in his white uniform and gold-laced cap, standing behindhim.

  "What is this S.O.S., Ready?" he demanded. "What craft is in distress?"

  "An airship, sir. The _Adventurer_, bound from New Orleans for Havana,Cuba."

  "By Neptune! I recall now reading that two aviators were going to makesuch a foolhardy attempt."

  "What kind of an air-craft is she, sir? Do you recall?"

  "Why, one of those flying-boats, as they are called, I believe."

  "A big aeroplane fitted with a boat's hull?"

  "That's the idea. But did they give you their position?"

  Jack handed over the figures.

  "Here they are, sir. But the current from the drifting airship was soweak that I cannot be absolutely certain as to their accuracy."

  "Well, we'll have to take them for what they are worth," said thecaptain, scanning them.

  "Roughly, they are on our course, sir," ventured Jack.

  "Yes, we can almost make a landfall on them if you got the positionsright. I'll have full speed ahead signaled. Poor fellows, their plightmust be desperate!"

  He hastened off to give the necessary orders, while Jack went back tohis instruments; but, although he tried with all his might to getanother whisper, he could hear nothing.

  Either the wrecked airship had gone to the bottom, or else, water havingreached her storage batteries, she could no longer send out word.

  But Jack raised another ship,--the _City of Mexico_ of the Vera Cruzline.

  "What's biting you?" the flippant operator inquired.

  "Just got word that a wrecked airship is floating about on the sea,"flashed back Jack, and gave the latitude and longitude.

  "Why, we'll be there almost as soon as you," was the reply.

  "All right, let's make it a race," called Jack. "It is one for a goodcause."

  "Surest thing you know. See you later."

  The _City of Mexico's_ wireless man cut off. The third officer came intothe wireless room.

  "Ready, the old man wants you to make out a bulletin for the passengers.They'll go wild over this."

  Jack quickly typed off a bulletin.

  "Shortly before noon, in communication with wrecked and drifting flying-boat _Adventurer_. She is about twenty miles to the Southwest. We are hurrying at top speed to her assistance and should be there in a little over an hour's time.

  "Ready, Chief Operator, _S. S. Tropic Queen._"

  The excitement that followed the posting of this notice on the bulletinboard at the head of the saloon stairs may be imagined by those who havepassed long, dreamy, uneventful days at sea, when even the sight of adistant sail provides all manner of topics of conversation.

  But now they were steaming at top speed toward the hulk of aflying-boat--that is, provided she was still on the surface. The shipbuzzed and hummed with vibrant excitement. Passengers lined the rails,and some of the more excitable even tried to swarm into the rigging,from which exalted positions they were swiftly ejected.

  Black smoke poured from the _Tropic Queen's_ funnels, and the speed ofher accelerated engines caused a humming vibration to run through herframe like the twanging of a taut fiddle string. On the bridge,white-uniformed officers stood, with glasses in hand, all on the alertto catch the first black speck on the sparkling sea which might revealthe location of the wrecked air adventurers.

  Forward, on the forepeak and in the crow's nest, lookouts had beendoubled. And excitement was added to the race to the rescue when itbecame known that the _City of Mexico_ was speeding from the southwardon the same errand of mercy.

  CHAPTER XVII

  A DERELICT OF THE SKIES

  "What a wonderful thing wireless is!" remarked Sam, as the two youngoperators stood gazing from the upper deck where their "coop" wasperched.

  "Yes, if that flying-boat hadn't carried even the small, weak equipmentshe has, it would have been all off with them," agre
ed Jack; "that is,if they are not at the bottom now."

  "Oh, I hope not!" cried Sam.

  "Same here. But still, the sudden way that message cut off looked odd."

  The boys said little more, but kept their attention concentrated,waiting for the first sharp, quick cry that would announce that thederelict of the skies had been sighted. It was nerve-racking, thewaiting for that shout.

  It seemed that hours had passed, when suddenly there came a sharp barkfrom the bows. A keen-eyed salt stationed there had seen something evenbefore the officers on the bridge had sighted it through theirbinoculars.

  "What is it, my man?" hailed Captain McDonald through a speakingtrumpet.

  "Can't just make out, sir. It might be a big whale, but it looks to melike a boat."

  The officers scrutinized the object pointed out through their glasses.It lay some miles from the ship, spread out darkly on the blue,gently-heaving sea.

  "Can you see any human beings on board it?" demanded Captain McDonaldanxiously of Mr. Metcalf.

  "No, sir, I--yes, I do, too. One man. He is standing up, waving."

  "Give me the glasses, Metcalf."

  The captain took the binoculars.

  "Yes, you're right; there's a man on board. But how long he will keepafloat, I don't know. Lucky the sea is calm."

  "You may well say that, sir. In my opinion, whatever he is standing onis due to sink before long."

  "My opinion, too. But hullo, what is that coming up over the horizonthere?"

  "That smoke, sir? That must be the _City of Mexico_."

  "Yes, you're right, it is. I can see her masts now. She's coming upfast."

  "We don't want to let her beat us, sir."

  "No, indeed; signal below for more speed."

  Mr. Metcalf jerked the engine-room telegraph. A quickened impulse of thesteel hull followed. Inky smoke rolled in volumes from the two funnelsof the big ship. Never had she gone faster. Under the forced draught inthe sweating stokeholds below, the firemen toiled desperately. Steamscreeched from the 'scape pipes in a constant roar, testifying to thebig head of power being carried in the ship's boilers.

  It was a race to thrill the most critical, and a contest of speed, too,which had, as its goal, a human life; for, from the frantic signals nowbeing made by the man on the drifting flying-boat, it was plain that hedid not expect to keep above the water much longer.

  The _Mexico's_ wireless man was signaling Jack.

  "Hit it up, you _Tropic Queen_."

  "We're doing nicely, thank you," came back Jack. "What's the matter withyour old sea-going smoke wagon?"

  In this way the messages between the two on-rushing steamships wereflashed back and forth above the sparkling sea, while the drama of therace for a life was going forward.

  And now the passengers had caught sight of the tiny object adrift on thevast ocean. A hoarse cheer ascended to the boat decks, in which theshrill voices of women mingled. They were shouting encouragement andadvice to the castaway of the sky.

  He replied by waving. The speed of the ship suddenly was reduced. UnderQuartermaster Schultz a boat crew was made up. Jack begged to be allowedto be one of them and, to his delight, the captain told him to cutalong.

  Sam, although deeply disappointed at being left behind, neverthelesscheered with the rest as the boat was lowered and struck the water witha splash. Then, as the steamer's propellers ground in reverse to checkher way, it dashed off toward the stricken flying-boat.

  The craft could be seen quite plainly now--a dainty affair with golden,shimmering wings supporting a boat-like structure amidships. Jack wasfamiliar with the general construction of flying-boats, the very latesttype of aeroplane, from pictures he had seen in magazines, but he hadnever seen a real one before. He marveled that so frail looking a craftcould have made her way so far out to sea.

  But as they neared the stricken airship, shouting words of encouragementto her lone occupant, a startling thing happened. Simultaneously a groanburst from the throats of the boat crew.

  The flying-boat vanished from the surface of the sea as if she had beena smudge wiped off a slate with a sponge.

  CHAPTER XVIII

  A LEAP FOR A LIFE

  Had the lone navigator of the craft perished when she gave the lastswift and decisive plunge to the bottom? A groan that went up from thedecks of the _Tropic Queen_, which had steamed quite close, seemed toindicate that the enthralled onlookers thought so.

  But suddenly Jack gave a shout:

  "There he is! Over there! Pull for your lives, men!"

  The brawny arms of the oarsmen needed no encouragement. Every man bentto his work till the stout ash sweeps curved and their backs cracked.

  The boat flew across the water to a tiny, bobbing, black dot, the headof the castaway aviator. As they drew closer, they could see his faceturned toward them imploringly. He was a young man, black-haired andapparently good-looking, although they did not pay much attention to hisappearance just then.

  As they drew alongside, his strength suddenly seemed to give out afterthe brave struggle he had made, and he disappeared under the water. Evenas he did so, a figure leaped from the boat in a long, clean dive. WhenJack, for it was the young wireless man who had made the daring leap,reappeared, he held in his arms the body of the half-drowned man.

  He held in his arms the body of the half-drowned man.]

  A dozen eager hands drew them aboard the boat, while from both the bigsteamers, for the _City of Mexico_ had now come up, there arose a mightyroar of recognition for the plucky rescue. From the _Mexico's_ signalhalliards a message of congratulation was fluttering as the _TropicQueen's_ boat started back for her ship. In the wireless coop, Sam andthe _City of Mexico's_ operator were busy exchanging comments by radio.

  The aviator soon recovered and was able to talk to Jack as the boat crewpulled back. His name was Ramon de Garros, and he was a young Frenchman.He was making the flight from Palm Beach to Havana in the flying-boat inthe interests of a hotel company owning giant hostelries in both places.

  He had set out the day before, thinking to finish the flight within afew hours. Instead, an accident to his engine had compelled him toalight on the surface of the ocean. Then adverse winds had driven himfar off his course, and finally his gasoline had given out. He luckilyhad a wireless apparatus on board, a new, light device with which he hadbeen experimenting for the government. If it had not been for this, hischance of rescue would have been slim.

  The rails of the ship were lined with men and women who gave thereturning rescuers a hearty roar of welcome as they drew alongside. DeGarros, with the volatility of a true Frenchman, waved his hand to showthat he was not injured. This brought another cheer.

  The boat was hoisted home and the crowd pressed about it as Jackclambered out and extended his hand to De Garros, who was still feeblefrom his trying experience. Men and women tried to grasp Jack's hand,but he brushed past them, feeling awkward and embarrassed as heconducted De Garros to the captain's cabin.

  In the crowd was Miss Jarrold, and as they passed her, to Jack'sastonishment, she and De Garros exchanged looks of unmistakablerecognition. The girl turned away the next instant, but De Garrosexclaimed to Jack:

  "What is that young lady doing on this ship?"

  "She is accompanying her uncle," rejoined Jack. "I believe they are on apleasure cruise."

  "Her uncle is on board?"

  There was a note almost of anxiety in the rescued aviator's voice as heput the question.

  "Yes. You know him?"

  The reply astonished Jack. De Garros' tone was more than vehement as herejoined:

  "Know him! I know him too well! I--but never mind about that now."

  Jack had no time to ask questions; indeed, he would have considered itimpertinent to have done so. They now reached the captain's cabin andthat dignitary himself came forward to greet De Garros. The aviatorexplained that he wished to be transported to Kingston, Jamaica, whichwas the first port of call of the _Tropic Queen_, and that ther
e hewould cable for money for his passage and so forth.

  Captain McDonald greeted him warmly, and clothes from the wardrobe ofthe third officer, who was about his size, were found for De Garros, whowas beginning to shiver, warm though the air was. Jack had to hurry offto relieve Sam at the key. As he left, he and De Garros shook handswarmly.

  "I shall see more of you," said the young Frenchman.

  "I hope so," responded Jack. "I should like to hear more about your airvoyage, when you have time."

  "I can always make time for the man who saved my life," was therejoinder of the aerial castaway.

  "Oh, shucks!" exclaimed Jack, not being able to think of anything elseto say.

  Then he hurried back on the job. Half an hour later, in dry clothes, hewas at his key again and exchanging joshes with the operator of the_Mexico_, as both the stately crafts stood on their courses once moreafter participating in what was, probably, the first rescue of an aerialcastaway on record.

  CHAPTER XIX

  A CALL IN THE NIGHT

  Sapphire days of steaming through deep blue tropic seas beneath acloudless sky passed by dreamily. The _Tropic Queen_ was now in theCaribbean, rolling lazily southward through azure water flecked withgolden patches of gulf weed--looking like marine golden-rod. Fleeingflocks of flying fish scuttered over the water as the steamer's sharpbow nosed into the stuff, like a covey of partridges rising from coverbefore a sportsman's gun.