The Boy Inventor’s Wireless Triumph

The book Jack Chadwick had been reading,—a volume dealing with some rather dry experimental work,—slipped from his fingers and fell with a crash on the floor of the veranda. At the sudden interruption to the sleepy, breathless calm of Lone Island on a July noon, his cousin Tom Jesson, sixteen, and more than a year Jack’s junior, looked up from the steamer chair in which he, too, was extended, with one of his quiet smiles.

Suspending his task of wrapping some new condenser plates with glittering tin-foil, he gazed about him. In front of the bungalow was a strip of dazzling white sand,—the beach. Beyond shimmered the cobalt-blue waters of the Gulf of Mexico. At a small wharf lay a capable-looking motor cruiser, painted white and about forty-five feet in length. She had been moored thus for the past seven days—ever since Jack and his cousin and their colored attendant, Jupe, had landed on the island after an uneventful passage from Galveston.

“Dozed off,” chuckled Tom, regarding Jack as the latter’s eyelids closed drowsily; “well, I don’t know that I blame him. Waiting on Lone Island with nothing to do but read, eat and sleep, does get monotonous after a week of it.”

Suddenly a gong, affixed to the freshly painted wall above their heads, broke forth in a wild, insistent clamor.

“Clang! C-l-a-n-g! Clang! Clang!—Clang! Clang!”

The effect on Tom was electrical.

“L-I in the Continental Code!” he exclaimed springing to his feet. “Hurray, Jack, old boy! Wake up! It’s our call at last!”

Jack Chadwick galvanized from his nap into vibrant action with hardly less suddenness than had marked Tom’s arousing. Three times the gong, connected by an ingenious arrangement of Jack’s with his detector, beat out brazenly the call of Lone Island. Then came the signature:

“S-K.”

“Whoop! It really is the Sea King at last!” exclaimed Jack, his blue eyes dancing. The lees of sleep had cleared from them as if by magic.

“Race you to the wireless station, Tom!” he shot out, jumping from the veranda without bothering about the steps.

“You’re on!” was the instant response. Like a flash Tom was at his side.

The few dozen yards between the bungalow and the shed of raw, resinous-smelling pine lumber that housed the wireless was covered in less time than it takes to tell it. Panting from their dash through the heavy sand the two lads flung themselves, shoulder to shoulder, at the door.

“Dead heat!” laughingly proclaimed Jack, as he opened the portal and hastened to the array of shining instruments which occupied most of the space within.

All this time, behind them, the bell had kept up its insistent tocsin. With a quick movement Jack “threw” a “knife-blade” switch. Instantly the resonant drone of a dynamo filled the small sun-heated shack. Bending forward. Jack depressed the sending key.

Flash! C-r-a-s-h!

A wriggling snake of blue flame leaped, like a live thing, between the polished sparking points.

Alternately pressing and releasing his key. Jack sent an answer to the message. With nimble fingers he directed the powerful electric impulses, which were winging into space from the lofty aerials stretched between their masts above the shed.

While he did this with one hand, with the other he deftly adjusted the bright metal head band with its twin receivers that fitted over each ear. This accomplished, he drew toward him a pencil and a pad of paper.

“L-I! L-I! L-I!”

Crackling and squealing the powerful spark volleyed across the gap, and rushing into the aerials went flashing hundreds of miles through the ether.

Then came a pause. Tom, his hand on Jack’s shoulder, leaned eagerly forward and over him, watching for the first words of the message from space to be written on the pad.

All at once Jack began to write. His fingers flew fast in response to the flood of dots and dashes that came beating against his ear drums, transmitted by the sensitive diaphragms of the receivers.

To an untrained ear the soft tappings would have sounded as vague and undefined as the footsteps of a fly on a sheet of sensitive matter. But to Jack, the whisperings winging their way in three hundred meter waves through space were as clear as a story read aloud.

As he wrote, shoving his pencil over the sheets as fast as he could, Tom began to gasp.

“Great ginger-snaps!” he choked out, and then, “Well, we were sighing for action, and it looks as if we’ll get it in big, juicy chunks before we’re much older.”

While the message, destined to have such an important effect on their immediate future, is still pulsing through the air, we will take the opportunity to place the reader in closer touch, so to speak, with our two lads. Jack Chadwick, then, was the only son of Professor Chester Chadwick, an inventor, whose various discoveries in many mechanical fields had resulted in gaining him a handsome fortune. Jack’s mother had died when he was a tiny lad, and, as he was an only son, he had been brought up in constant association with his father. Almost as soon as he had mastered his earliest lessons Jack was familiar with his parent’s laboratory and workshop, and Mr. Chadwick, delighted at the interest the boy displayed in science, had made him a close companion.

When Jack was twelve years old a new interest entered his life. His cousin, Tom Jesson, came to live with them at Mr. Chadwick’s handsome home on the outskirts of Boston. Tom was the son of Jasper Jesson, the noted traveler, and, like Jack, he was motherless. Mr. Jesson had, some time before, accepted a commission from a scientific institute to travel and collect antiquities in the then little-known territory of Yucatan. From this expedition he did not return within the year allotted him to complete his researches.

Time went on and no word came from him, and at length he was given up for lost even by the most hopeful of his friends. And thus it was that his son Tom, then ten years old, came to High Towers, Mr. Chadwick’s estate, even then known as the home of a famous inventor.

And so Jack and Tom had practically grown up together in close association and with kindred interests.

To two lads of inventive mind, no more delightful field for their experiments could have been imagined than High Towers. A park of some fifty or sixty acres surrounded the house, which, among other features of a country estate, possessed a small lake. On this sheet of water Jack and Tom tried out models of a dozen different kinds of craft before they were fourteen. Professor Chadwick gave them practically “the run” of his workshops and experimental sheds, besides instructing them in scientific investigations.

Among other things, the lads had constructed a complete miniature railroad on the grounds, and had also built gliders of various types. But their most recent “craze” had been wireless telegraphy. With a dozen lads of their own age they had formed a “Wireless Club,” which met at High Towers every month. But, with the summer vacation, the members of the body had scattered, leaving only Jack and Tom to carry on the work. As Professor Chadwick stinted his son in nothing pertaining to his chosen pursuits, the two lads had assembled as complete an amateur station as could be found in the country.

In addition to the latest instruments and appliances, their natural ingenuity had enabled them to invent several additional features, some of them patentable,—as, for instance, the call-bell which tapped out the mysterious summons to the island station.

Which brings us back to Lone Island and to an explanation of how the two lads and Jupe, their faithful colored attendant, happened to be quartered on this low-lying, sandy, rather desolate patch of land off the coast of Texas, not far from the mouth of the Rio Grande. The islet belonged to Professor Chadwick, being part of an estate which had been owned by his wife, the daughter of a Texas cattle man. The lads had already camped there a winter, and knew the vicinity well.

About two months before this story opens, Professor Chadwick had left home, bound, so he informed the lads, on a biological investigation cruise among the Florida Keys and the West Indies. The lads had heard nothing more of him, or of his steam yacht, the Sea King, with the exception of a letter from Key West, and another from the island of Jamaica, stating that all was going well.

Imagine their bewildered astonishment and excitement therefore, when, two weeks before, a brief letter came to High Towers telling them to proceed, with Jupe, to Galveston, where the motor cruiser Vagrant would be awaiting them. Their instructions continued to inform them that they were to equip the Vagrant with wireless, and also purchase a portable bungalow and shed, with which to establish a wireless station on Lone Island. The letter, signed by Professor Chadwick, closed in his customary abrupt manner, without vouchsafing any explanation of his orders.

But Jack and Tom hardly needed any. The letter opened up before them a delightful vista of fun and adventure.

“Just fancy, a wireless island all to ourselves!” Jack had exclaimed as the boys joined hands in a wild war dance of delight. They had pleasant recollections of former jolly days in camp on the Gulf.

The letter enclosed a liberal draft on Professor Chadwick’s bank, and within forty-eight hours after receiving the missive which was to mean so much to them, the two cousins and chums, with the faithful Jupe attending them like a black shadow, were off for Galveston. On arrival there they went to the boatyard mentioned in the Professor’s letter, where they found the Vagrant,—the smart craft already mentioned as lying at the Lone Island wharf,—already equipped for sea, awaiting them.

To install a wireless plant on board did not take long. The most difficult part of their task lay in finding a suitable mast for the support of the aerials. Jack solved this problem by constructing a telescopic staff of steel tubing which, when not in use, could be lowered to a height of twelve feet. In use it could be raised to an altitude of sixty feet, giving a very fair radius of scope.

The materials for the wireless on the island, like those for the floating plant, had been brought from Boston. But the portable shack and bungalow were purchased in Galveston.

The Professor’s letter had instructed the lads to wait on the island for a message by wireless. Now it had come; come, too, with a startling suddenness that might be likened to a jolt. Tom, watching Jack’s fingers with burning eyes, finally saw this message inscribed on the receiving pad:

“Lone Island Station.—Proceed with all speed to Long. 96° W. by Lat. 27° N. Urgent. We are in dire peril.—Bangs, operator Sea King.”

The patter of the electric waves against the receivers ceased. No further word came, and Jack, after a brief interval, took off the headpiece and laid it down beside him on the table. For an instant the message, so utterly, wildly different from any they had expected, almost deprived him of speech.

Now his faculties rushed back, but he did not speak. Instead, he grounded the aerials by throwing the switch, and leaped to his feet with such impulsiveness that the stool on which he had been sitting went careering to the floor.

“Come on, Tom,” he cried, darting for the door.

As he ran he stuffed the message into the pocket of his linen jacket. Tom shot out of the shack after him.

“You’d better lock——” he began.

“Send Jupe to do it,” was the backward flung rejoinder, as Jack sprinted for the bungalow, “we’ve got to get grub on board and fill the water tanks within fifteen minutes.”

“And then what?”

“To sea—at top speed! The best the Vagrant can do will be none too quick! They need us out there,” he flung his arm seaward in an embracing gesture, “need us mighty bad, and it’s up to us to make a record run to the rescue.”

“They said nothing as to what was the matter?”

Tom propounded the question ten minutes later as the two lads busied themselves in the after cabin of the Vagrant, stowing provisions hastily. “No, not a word. If only I could have got in communication with them again I might——”

At this point a very black, very round, very good-natured negro countenance appeared in the companion way above them.

“Ah’se done locked up, Marse Tom. Anyfing else yo’ all might be requirmentin’ ob?”

“No, Jupe. I guess we’re about ready for a start. Let’s see,” and Jack rapidly ran over a mental list of what they had on board.

“Yes, we’ve got everything. The water tanks are full, plenty of gasolene,—it’s a good thing we brought that extra stock from Galveston,—grub, O. K., and—better get forward and start the motor up, Tom.”

Tom needed no second bidding. He shot up the companion way three steps at a time, almost upsetting Jupe, who stood at the summit on deck. He scurried to a hatchway forward of amidships and dived below. A hasty glance over the forty horse-power, four-cylindered, four-cycle engine showed him that everything was in working order. An adjustment of the force-feed lubricator, a swift examination of the magneto, a few turns of the starting apparatus, and a rhythmic series of explosions as the crank shaft began to revolve, and the Vagrant was ready, so far as her machinery was concerned, to begin her dash across the Gulf.

In the meantime, Jupe had been hustled ashore by Jack, who had taken up his position at the wheel, and in a very few seconds the lines that held the motor cruiser to the wharf were cast off. Jupe made a flying leap aboard as the tide swung the Vagrant from her resting place.

At the same instant Jack jerked the bell pull, which signaled Tom in the engine-room below to throw in the clutch, and as the propeller began to revolve the Vagrant backed slowly out. In a few minutes Jack rang in the “Go-ahead” signal, and swinging the doughty little craft in a short semicircle, the young captain headed her almost due S. E.

Tom emerged on deck wiping his hands on a bit of waste.

“Everything all right below?” inquired Jack as his cousin took up a position beside him.

“Running like a dollar watch,” was the response.

“How much speed can we get?”

“Well, twelve knots is her registered gait, but I might coax a bit more out of her.”

“Try and get all you can.”

“I will. What time do you think we ought to reach the vicinity of the Sea King?”

“It’s a trifle over a hundred miles to the spot at which she gave her bearings,” was the response, with a glance at the chart which lay exposed in the uncovered case in front of the wheel. “It’s now just one o’clock. Say, about midnight.”

“Phew! You propose to pick up a yacht, whose location you know only vaguely, in the dark?”

“Not so dark, either. There’ll be a moon at ten-thirty. Anyhow, if we keep right on this course we’re bound to come within a few miles of the given bearings.”

“I guess that’s so. Well, I’m off below to watch the engines.”

“Better start the dynamo and get some ‘juice’ into the storage batteries. I mean to try the wireless again before long.”

Tom nodded, and vanished below once more. Jupe came forward from the stern, where he had been coiling lines and generally setting things to rights.

“Marse Tom,” he said, with some hesitation, “is dere any objection to informationing me concerning de percise objec’ ob dis here penguination?”

“Why, no, Jupe,” rejoined Jack, with a smile at the old negro’s remarkable choice of what he himself would have called “highfaluting” words, “the Sea King, with my father on board, as you know, is in some sort of trouble, and we are going to the rescue as fast as we can.”

“How you find out dat, Marse Jack?” asked the old man, with a tinge of suspicion in his voice.

“By wireless, Jupe.”

“What!” in a tone of frank unbelief, “yo’ all mean ter tell me dat dat birdcage rigamarole ob yo’s done tell yo’ all dat?”

“That’s right, Jupe.”

“Sho’ now! Yo’ ain’t foolin’ de ole man, Marse Jack? Dat conjo’ wire done tell yo’ all dat?”

“Of course. I should have thought that you’d seen enough of it at High Towers to know what it could do.”

“Humph!” the old negro scratched his head in a puzzled way, “yo mean dose eccentrical wabes, as yo’ call ’em, done come all de way frum Marse Chadwick’s boat to de island?”

“Just what I do, Jupe. It’s the same thing as chucking a stone in a pond. You know how the waves and ripples spread out and out in circles that get bigger and bigger?”

“Ya’as, sah.”

“Well, it’s the same thing in wireless. Instead of a pond you’ve got the air, or the atmosphere; instead of a stone, you’ve got an electric impulse from the antenna.”

“An’ when dat eccentric ’pulse go ’way from dose—dose—aunties, it jes’ spread and spread like de ripples on a pond?”

“Yes. The waves spread till they strike another wireless apparatus ‘in tune’ with them.”

“An’ yo’ birdcage fiddle was tuned to de same pitch as de Sea King’s?”

“That’s right, Jupe. You’re catching on fast We both use three hundred meter waves. That was agreed upon. Thus, you see, our station caught the message from the disabled yacht.”

“Humph! But s’pose dere was some odder station dat had its fiddle tuned de percise same way?”

“Why, then they’d have caught the message, too.”

“An’ dey’d know, too, dat de po’ Sea King done busted?”

“I suppose so,—yes. But why do you ask?”

“Fo’ jes dis reason, Marse Jack,—if any ob dem ole wreckers dat used ter hang about dese parts got dat message, maybe dey gwine ter go out dere, too.”

“I guess not, Jupe. I never heard of any such rascals who had a wireless equipment.”

“Den how ’bout dat po’ful mysterious X. Y. Z. I done heard yo’ an’ Marse Tom talkin’ ’bout at supper de odder night?”

“Oh, X. Y. Z.!” exclaimed Jack with a laugh; “well, he is a mystery for a fact. Some amateur on shore or some place, I suppose, who just happened to get tangled up with our slaves when we were practicing.”

The “X. Y. Z.” referred to had made himself manifest three days before, while Jack and Tom were conducting some experiments with their sending apparatus. In the midst of their work a confused sound had broken in upon them, and Jack, on tuning his apparatus to catch the “stranger” waves, had intercepted an apparently meaningless message signed X. Y. Z. The message consisted of a jumble of numerals which, the two lads had little difficulty in deciding, was a code of some sort. The catching of such messages being common enough in the north, they gave the matter little more thought and, in fact, till Jupe mentioned it. Jack had not recollected the occurrence at all. Now, however, as Jupe moved off forward to complete his work, he caught himself wondering who X. Y. Z. might be. He wished that they had taken down the intercepted message and devoted some of their leisure time to deciphering it; but the urgent business now in hand soon drove such thoughts out of the young navigator’s head.

Tom reappeared on deck, the inevitable bit of waste in his hands.

“I’ve adjusted the magneto,” he announced, “and I guess we’re turning over a bit faster than ordinary.”

“Good for you,” nodded Jack approvingly, “every minute counts on a job like this.”

At every turn of the shaft Jack’s heart was bounding with keen anxiety. The same might be said of Tom’s condition. The very vagueness of the message from the air, fraught as it was with the sense of disaster, added to their mystification and eagerness to reach the scene.

But mingled with all this, as the two lads stood side by side on the miniature bridge of their speedy little cruiser, was a fierce sort of pleasure as they sped through the rolling swells of the gulf, hurling white masses of foam aside from the sharp “cutwater.”

Behind them the coast line lay like a dim gray scarf stretched along the blue horizon. The keen, ozone-laden wind struck their faces with an invigorating tang. It was great, glorious, exciting to be out here on the broad bosom of the gulf, guiding a speedy motor craft toward unknown adventures. The zest of achievement, the glory of grappling with obstacles as yet unseen and hardly guessed at, ran hot in both boys’ veins. Fast as the Vagrant was, she seemed to them to crawl, and yet, thanks to Tom’s skill as an engineer, she was reeling off her thirteen knots with the regularity of a sleeping infant’s breathing.

“Jupe!” called Jack presently, “come aft and spell me at the wheel for a while. I’m going to send a few questions into the air,” he added to Tom.

“Good. We’ve got plenty of ‘juice.’ Shall I go below and send up the mast?”

“Yes. Better run it up to its full height. It won’t hurt in this light breeze, and I want all the radius I can get.”

“Right you are.”

Tom descended once more. The base of the telescoping aerial mast was in the forepart of the engine-room. A hand winch operated it much in the same manner that a fire department’s extension ladders are sent aloft. It did not take Tom long to extend the slender, yet pliant and strong steel spar heavenward to its fullest length.

At its truck, or summit, was a pulley, through which halyards attached to the aerials had been rove. Jack had gotten these out while Tom had been busy below, and in a remarkably short time the slender antenna, or aerials, were strung from mast tip to deck. There were four separate wires of stranded phosphor bronze attached to wooden spreads, and properly insulated. From them a wire led back to the instruments attached to a table in the forepart of the cabin.

The aerials being up Jack, after satisfying himself that everything was shipshape, made for the cabin. Seating himself at the wireless table he sent a signal crashing out into space.

“S-K! S-K! S-K!”

Then, after a pause:—

“L-I.”

There followed a period of listenings with the receiving switch over and the “watch-case” receivers closely clamped to the young operator’s ears. But no answer came.

A worried look crept over Jack’s countenance. This silence was ominous. Once more he manipulated the key with nimble fingers. The spark squealing and crackling shot bluely hither and thither.

But to the electrical appeals sent broadcast into the atmosphere, space vouchsafed no answer.

A sudden break in the rhythmic pulse of the engine reached Tom’s alert ears at this instant. Without speaking he hastened from the cabin to the engine-room, using, for this purpose, a door cut in the forward bulkhead. He found that one of the cylinders was missing fire and traced the trouble to a badly sooted plug.

While he was adjusting the trouble Jack stuck to his key. He would pound out his “S-K” call furiously for an interval, and then listen intently for even the faintest indication of a response. The lad tried various adjustments, of the potentiometer, which regulates the voltage and current supplied to the detector, and operated his receiving tuning coil in various ways. But though he tried for wave lengths from two hundred meters up to fifteen hundred, not a whisper came out of the void of silence about them.

“I’ll call once more,” said the lad to himself in a determined voice, “it’s our duty to do all we can and keep at it all the time. Of course, if the Sea King has met with a really serious disaster her wireless may be out of order and—Hullo! Here’s something coming now!”

Something was coming, sure enough!

As Jack clamped the receivers to his ears a hail of dots and dashes beat against his organs of hearing. Somebody was transmitting a message at a furious rate. Expert as the lad was, it was all he could do to make head or tail of it. His pencil fairly flew over the recording pad, and when he got through he had nothing for his pains but a sheet covered with figures, and again that annoyingly mysterious signature X. Y. Z.

Tom had returned to the cabin while Jack’s pencil was scurrying across the paper. He leaned over, the other lad’s shoulder and watched intently. When Jack stopped and affixed the signature X. Y. Z., he looked up at his cousin wonderingly.

“It’s X. Y. Z. again. He was sending like blue blazes, too. What do you make of it?”

“Blessed if I know. Using his cipher again, too, isn’t he? Say, Jack! See here,—X. Y. Z.,—whoever he is,—is within our radius right now—at this instant. Call him, and see if you can find out who or what he is and where his station is. If the Sea King is badly off he may be of great assistance to us.”

Jack switched his current over for sending out a call. With a puzzled frown on his face he adopted Tom’s suggestion.

“X-Y-Z! X-Y-Z! X-Y-Z!” he flashed out, and then added the signature “L-I.”

“Now to see if we get any result,” he said, adjusting the receivers to his ears and throwing the switch for the detection of a reply. He had not long to wait.

“L-I! L-I! L-I!—X-Y-Z!” came billowing through the ether, “what do you want?”

“We are proceeding to rescue of disabled yacht Sea King,” flashed back Jack. “Where are you? Can we rely on you for help?”

A long silence followed. Then the Continental code began to throb and beat in the receivers, once more.

But it was another question that came.

“Where is yacht Sea King?”

Jack flashed the bearings as he had received them earlier in the day, and then repeated his former question. But no reply came. For an instant the lad thought he had got out of tune with the wireless mystery, but although he ran the gamut of the tuning coil, nothing more came. For all that was further heard of him, X. Y. Z. might have been as intangible as the atmosphere out of which he had projected his questions.

For half an hour or more Jack persisted in his endeavors to reach X. Y. Z. again, but finally gave it up as a bad job. Grounding his current, he laid down his head band and swung in his chair.

“Lost him?” inquired Tom.

“I’d rather say that he lost us,” responded Jack, “it must have been a deliberate cut-out. One second he was coming strong and then—silence. How do you figure it, Tom?”

“I don’t attempt to. I give it up, unless X. Y. Z. is some sort of a wireless lunatic.”

Jack gave a rather mirthless laugh.

“Hardly. Or, if so, I begin to fear there is some method in his madness. You notice that he only seemed to want to find out the exact position of the Sea King?”

He indicated the writing pad on which the entire conversation was recorded, as was the young inventor’s wont.

Tom nodded.

“I see that plain enough. I am inclined to think. Jack, that you made a big mistake in giving that chap the location of the Sea King.”

“You do? Why?”

But as he spoke there came into Jack’s mind an uncomfortable recollection of what Jupe had said about wreckers.

“I don’t know just why,” was Tom’s frank response; “didn’t you ever have a feeling that somehow something you had done had been,—quite unintentionally,—a bad blunder?”

“I know what you mean. I wish to goodness we knew who this X. Y. Z. was,—or is.”

“Easy to find out.”

“Easy to find out!” echoed Jack with a fine note of scorn, “about as easy as—as——”

“Translating that cipher,” broke in Tom. “If we can read it we may have a good clew to Mister X. Y. Z. and his doings.”

Jack laughed aloud.

“Yes, ‘if,’” he said mockingly, “and if——”

“I think I can do it,” said Tom quietly.

“You do! Well, tackle it at once, then. I’m kind of worried, I don’t mind telling you, about that chap and his questions.”

Tom picked up the sheet of paper with the numbers inscribed on it in a seemingly hopeless jumble.

“I’ll take it to the engine-room with me and try to work it out and keep an eye on the motor at the same time. I like tackling propositions of this kind.”

“Yes, you always were a nutcracker at school; but I fancy you’ll find that the toughest yet.”

“I’m not so sure about that. Ciphers divide themselves up into groups pretty well, and I’ve half an idea that this is a very common one. Suppose you take a look at Jupe and take the wheel while he gets supper.”

“By ginger, I’d forgotten all about that till this moment.”

Jack glanced up at the clock affixed to the bulkhead.

“Almost five o’clock. Time has flown certainly. Well, good luck, Tom, with that mess of figures, and if you find out anything from them about X. Y. Z. you’re entitled to a big hunk of credit on a silver platter.”

Jupe, so Jack found, had kept the Vagrant on her course to a hair’s breadth. The old fellow had been a sailor in his younger days, and the waters they were now traversing were not unfamiliar to him. He hailed the news that he was to get supper with pleasure, however.

“Ah’ll cook yo’ boys as fine a meal as yo’ ebber sat down to,” he promised, as with a broad grin he surrendered the wheel and made aft to the galley, which was a small room forward of the cabin and between it and the engine-room.

It was an hour later that Tom appeared on deck with a knitted brow, and several sheets of paper covered closely with cabalistic figuring.

“Well?” said Jack.

“Well, I’ve worked it out, and——”

“You know who X. Y. Z. is, I hope?”

“Why, no,” was the response in a puzzled tone, “I don’t know who he is, but I’ve learned considerable of what he is,—and I don’t much like it.”

Jupe’s summons to supper ended the talk for the time being, and the two lads went below to eat a hearty meal while the colored man took a spell at the wheel. After supper they emerged on deck again, and as Jack took the helm Tom drew up a camp stool beside him, and seating himself, spread the figure-covered sheet of paper out on the chart case. He then switched on the shaded light, which caused a soft glow to reveal the cabalistic scribbling clearly.

“Now then,” he began, “in figuring out a cipher of this sort the first thing to do is to note what figure appears most frequently. Having ascertained this, it is safe to assume that such a figure stands for the most frequently occurring letter in the language,—always provided, of course, the message is in English.”

“Well?” interrogated Jack.

“We know that the most frequently used vowel in English is E. And, by the way, this translation proved fairly easy, because the transmitter of the message made a gap between each of his groups of figures, showing that each collection stood for a separate word.”

“I noticed that,—go ahead.”

“I was trying to show you something of the method; but I guess you’ve about grasped it. In figuring out the cipher I made groups of all the numerals occurring in your transcript of the message, and found that the number ‘five’ appeared most often. I assumed, then, that it stood for H. Working in this way, I found that the first word of the message was The. That Th stuck for some time, till I saw that the figures ‘twenty-five’ had been used to express the phonetic sound of Th.

“This gave me a valuable clew. I wrote down The and then passed on to the next words. Figuring as before, I assigned the number ‘three,’ which appeared alone, to the letter C. I was puzzled for a minute. ‘The C’ didn’t seem to mean a whole lot, but I let it go and passed on to the next word. Using my system I spelled out King, and then, of course, I realized that the C was a phonetic rendering for the first part of the yacht Sea King’s name.”

“Great guns!” gasped Jack, “then they are interested in dad’s craft and——”

“Wait a while; let me get the rest of it off my chest. I’m not going to tire your patience out by going through every step. I’ve told you enough to show you my method. As I got further combinations it became more and more simple till I finally had this message figured out:

“‘The Sea King is disabled. Trying to get bearings from you know who. Vagrant left Lone Island this P. M. going to rescue. You had better make all speed or they will beat you out. Am proceeding. X. Y. Z.’”

Jack’s lips emitted an amazed whistle.

“What sort of a maze have we blundered into?” he exclaimed. “This X. Y. Z., who is he? Who was he talking to? What are they after?”

“All of which questions will be answered by the time we arrive at the scene of the wreck, I imagine,” quoth Tom with a dry intonation; “in the meantime, it looks as if we are ‘it’ in this marine game of blind-man’s buff.”

“That’s the name for it, all right,” assented Jack, peering at his compass card. “Tom, old lad, I’ve a presentiment that we are going to blunder into something that will call for every bit of ingenuity and courage we possess.”

“And in the meantime,” said Tom, “it’s up to me to keep that motor turning over as she never turned before.”

“Um,—well, beyond knowing that X. Y. Z. is a dangerous factor, or seemingly so,” mused Jack, “we are about as far off as ever from knowing just where he fits into the problem.”

The night wore on, and still the Vagrant churned her way steadily across the dark waters of the gulf under the brilliant white stars of the southern sky. The phosphorescence slid by her in fiery green streaks as she cut her way along, and from time to time Tom emerged from below and “spelled” his cousin, and comrade, at the wheel. At ten o’clock Jupe served coffee and biscuits on the bridge, and shortly thereafter Jack had another try with the wireless. But space, as before, was mute as the Sphinx. From out of the darkness came no whisper as to the nature of the enigma into which the situation, evolved by that first message from the air, had developed itself.

Eleven o’clock came, and both boys commenced to strain their eyes into the velvety blackness ahead.

“We ought to be picking something up before long,” observed Jack, “unless—unless——”

His voice shook a bit. Between this lad and his father there was a deep bond of affection. Their close association had riveted the lad’s love for his parent even more strongly than is the case with most boys. As they neared the location where the yacht ought to be discovered, a feeling of painful suspense clutched coldly at his heart. Nor was Tom’s agitation much less. But the younger lad was more accustomed to suppress his feelings than Jack. He stood by his cousin’s side with tightly closed lips, as the Vagrant throbbed onward, but through his brain, like fires in a blast furnace, a constant succession of anxious thoughts flashed and agitated.

“Unless what. Jack?” said Tom at length.

“Unless—gracious, Tom, suppose—suppose that the Sea King has——”

There was no need for him to conclude the sentence. Tom knew well enough what the other dreaded. The ominous silence after that first message, the lack of any signals from the disabled craft whose vicinity they must be close to now if she were still afloat—all these things induced a gloomy presentiment of evil which Tom, no more than Jack, was able to shake off.

“It isn’t possible that she has proceeded?” mused Tom.

“Not likely. As I understood that message the location was given us so that we could make direct for her. If she had been capable of proceeding under her own steam, surely she would have made for Lone Island.”

“If only we knew something of the object of Uncle Chester’s mission, we might form a clearer idea of what has happened out here,” ventured Tom. “One thing is certain, the Sea King hasn’t struck a rock——”

Jack laughed mirthlessly.

“There isn’t a reef or a shoal within a hundred miles of her bearings, as given to us,” he said; “that’s what makes the whole thing such a baffling puzzle. Her boilers and machinery were new. I don’t see what can have happened to them, and surely if the accident had been of that nature, the despatch would have said so. It’s just the vagueness of the whole thing that worries me.”

“Complicated by Mister X. Y. Z., whoever he may be,” supplemented Tom. “Do you know, Jack, I’ve got a hunch that we, are destined to see that individual before very long?”

A sudden yell from Jupe, who was at the bow keeping a keen lookout according to instructions, cut the night.

“Marse Jack! Marse Tom! Look! Look dere, yondah!”

There was no need for Jupe to explain himself. Dead ahead, and directly on the Vagrant’s course, a bright streamer of flame slashed the sky like a scimitar of fire.

“A rocket!” exploded Jack.

As he uttered the exclamation the skyward end of the flaming ribbon burst into a diadem of brilliant scarlet stars.

“Here, take the wheel,” choked out Jack, seizing Tom by the shoulder and shoving him into the helmsman’s place.

With nimble fingers he unlaced the canvas covering of the Vagrant’s searchlight, snapped the switch on with a tiny sputter of green sparks. and the next instant a pencil of white light was sweeping the darkness ahead.

Back and forth it swept and suddenly steadied. As it did so the boys uttered a simultaneous exclamation of amazement. Into the field of light had suddenly swung, not the expected outlines of the Sea King, but the form of a low craft without masts or funnels, rushing, at what appeared to be terrific speed, toward the northeast.

“Jove!” burst from Jack’s lips, “what on earth is this fresh complication?”

He had hardly spoken before there came a crash of glass close to his hand, and something flew whistling by him. At the same instant the searchlight was extinguished, and from seaward, where they had last seen the speeding craft, came a dull “B-o-o-m!”

“Knocked that searchlight into smithereens,” was Tom’s exclamation as old Jupe, with an alarmed cry, came running forward at the sound of the screaming projectile and the splintering glass.

“At any rate,” was Jack’s grim retort, “they’ve shown us their hands. Tom, old chap, this thing is going to be bigger than we thought.”

“You think then——”

“That we are not the only persons interested in the Sea King. If I don’t make a big mistake, that shot was a message from our friend X. Y. Z.”

“It looks like it,” admitted Tom; “oh, if we could only glimpse the Sea King!”

“The rocket cattle from her. I’m sure of it. She must have mistaken the lights of that marine raceabout for our signals.”

“Let’s try an answering rocket,” suggested Tom.

“Won’t do any harm. Jupe, quit shivering like a jellyfish and get the rockets out. Two will be enough. Tom, you rig the tube.”

The firing apparatus, a cylinder of galvanized iron, was speedily rigged in place, and by that time Jupe, whose face was an ashen gray tinge, reappeared with the rockets, two powerful signaling instruments, two feet or more in length.

“All right, Tom, touch them off,” came from Jack, as the younger lad proclaimed that all was ready.

There was the sputter of a match, a burst of yellow flame and then, almost instantly, a roar and a shriek as the first of the signals shot aloft, trailing a long tail of golden fire. At two hundred feet it exploded in a shower of blue stars. Almost simultaneously, it seemed, another cluster of red stars were spattered over the sky.

“Hurray! That’s the Sea King, sure enough!” cried Jack; “see, they’ve answered us. Crowd her as much as you can, Tom, it’s a race for all we’re worth now.”

“I can get a bit more speed, but it means overheating the engines,” warned Tom.

“Never mind that. Put us alongside the Sea King ahead of that other chap, and I don’t care if you blow the engines up,” was the curt rejoinder.

Tom shrugged his shoulders as he went below, but a few seconds later the dial hand of the patent log crept up a notch.

“Fourteen knots!” exclaimed Jack, with a note of satisfaction, “we’ll beat her out yet.”

All at once, from out of the obscurity, a grim possibility materialized. Rushing straight for the Vagrant came a sharp bow, with a wave of white phosphorescent foam curling away from it on each side as it cleaved the swells.

“Great guns! They’re trying to ram us!” gasped out Jack as he sensed the meaning of this new peril.

He seized up the speaking tube and bellowed down to Tom with all the force of his lungs.

“Back! Back her for our lives!”

Round spun the spokes of the wheel fast as a revolving squirrel’s cage. The Vagrant’s forward way was checked, but not wholly. To Jack’s horror it seemed impossible that the other vessel could fail in her evident object of ramming the smaller craft.

Less than a few score of feet separated them now. He could hear the hiss of the other craft’s cutwater as it rushed down on them.

“Golly to goodness, Marse Jack, dey sink us fo’ sho’,” wailed Jupe, dropping to his knees in terror on the bridge.

Jack vouchsafed no reply. But the next instant he felt like giving a shout of joy. The backward revolving propeller of the Vagrant was “biting” the water. The motor craft’s forward impulse was checked. She hesitated, stopped, and slowly her bow began to swing. It was not a second too soon. As the Vagrant swung off, the other craft tore by at a vicious speed, and Jack saw that her bow was shaped like a man-of-war’s “ram.” So closely did she race across the Vagrant’s bow that he could see dim figures on her bridge, and could catch a torrent of maledictions, as those in command of the strange vessel saw that their evident purpose had been frustrated.

At the pace she was going. Jack realized that it would be some moments before she could be put on another tack for a fresh onslaught.

“Ahead! Come ahead!” he shouted down the tube, and the propeller of the Vagrant began to churn in a forward direction once more. The lads’ craft forged forward, crossing the troubled wake of the vindictive stranger.

“Glory be!” breathed old Jupe fervently; “ah could heah de angels’ harps dat time, Marse Jack.”

“I don’t know that I wasn’t in the same mental condition myself,” rejoined Jack, with a nervous laugh. His hands shook and his heart beat thickly. The escape had been narrow enough to unnerve older and more experienced persons than this boyish captain.

“Ahoy!” came a sudden voice out of the darkness ahead, “what craft’s that?”

“The Vagrant!” hailed back Jack, with a glad ring in his tones; “is that the Sky King?”

“Aye! aye! Thank heaven, you’ve come—in time,” was the answering hail from the yacht.

A moment later, against the stars. Jack could trace the spidery outlines of the larger vessel’s spars and wireless aerials and rigging.

“This is Jack Chadwick,” he shouted, not giving a thought to the stranger craft now, but in a torment of anxiety to know what it all portended, “is my father on board?”

There was a pause. Across the water there came a confused murmur of voices, but what they said was not audible.

“Sea King, ahoy!” hailed Jack impatiently, “is my father on board and well?”

“Your father is well, we hope, but he’s not on board,” came back the reply in somewhat hesitating tones.

“Not on board!” stammered Jack, feeling for an instant as if he had been struck a heavy blow, “then where is he?”

“Come alongside. Master Jack,” was the response, “there’s a lot to be told.”

The black hulk of the Sea King was plainly visible now, and Jack, steering carefully, with one hand on the engine-room signaling device, skillfully maneuvered the Vagrant alongside of the bigger craft. As he did so an accommodation ladder was lowered, and several heads appeared along the yacht’s rail.

“Stop her,” chimed the signal.

Then came the order to reverse and then “stop” once more. Jupe, with a line in his hand, leaped for the accommodation ladder. Tom, emerging on deck, took in the situation in a glance and made for the stern. He hurled another line, which was caught from above. In as short a time as it takes to tell it, the Vagrant was snugly moored alongside her larger consort.

Jack, with his head in a whirl, stepped from the bridge. Tom was at his side in an instant.

“Is all well with Uncle Chester?” he demanded impatiently. “Is he on board?”

“No, he isn’t,” came the staggering reply, in a voice that was half a sob. It was a bolt from the blue that had assailed the lad, and who will blame him for being utterly unnerved by the blow fate had just dealt him.

Tom was silent for an instant. Tidings that stun have a way of sinking in slowly. Then, as the two lads stood at the foot of the ladder, he flung his arm around Jack’s shoulder, and from his gritted teeth came speech:

“If harm has come to him. Jack, those who have caused it will have to pay—and pay big!”

And so the two lads ascended the ladder to the Sea King’s deck, followed by the awe-struck Jupe.

It was Ned Bang’s, the boyish wireless operator of the Sea King, who met them at the head of the ladder. Behind him pressed a ring of curious faces, the bronzed countenances of seamen. Some incandescents had been switched on as the newcomers gained the deck, and in the yellow light Jack saw that all the faces that gazed into his bore the unmistakable stamp of agitation.

Bangs, besides being the wireless operator of the Sea King, was something more. He had been a pupil of Professor Chadwick’s and a school fellow of Jack’s, and was quite a scientific adept along the lines he had chosen to follow.

But Jack and Tom exchanged merely hasty words of greeting with the youngster who stood facing them, pallid-faced under his coat of tan and shaken evidently by some recent shock.

“What is it, Ned? What has happened?” demanded Jack eagerly, as soon as the boys had clasped hands. “Where is father? Why are you out here alone?”

“It’s—it’s a long story. Jack,” half-stammered Ned. “I—I’m afraid that we who are here on board don’t show up to very good advantage in it. But you must be the judge of that. Shall we go below, where we can talk?”

There was a reticence, a hesitancy in his tones that irritated Jack, overwrought as he already was.

“I asked you a question, Ned,” he said in sharp tones, very unlike his usual affable ones, “where is my father?”

“I saw him last near Yucatan,” burst forth Ned miserably.

The reply was so utterly unexpected that it fairly took Jack and Tom off their feet. Ned had not seen fit to supplement his statement, but stood there with that same shamefaced expression playing over his visage.

“And you—you left him behind there?” broke out Jack, guessing part of the truth.

“We couldn’t help it,” wailed Ned wretchedly. “Wait till I tell you about it.”

Jack’s head swam. Behind the vague words he sensed a tragedy of some sort in that mysterious country which had already, so it was thought, claimed the life of Tom’s father, Mr. Jesson.

“How did the Sea King come to be off Yucatan?” inquired Jack, “her course, as laid out, was far to the east of that country.”

“I know that,” replied Ned; “but a gale blew us off our reckonings, and into as strange and terrible a series of adventures as you ever heard of in the wildest fiction.”

“Tell us about it,” demanded Tom crisply, cutting short Ned’s rather hysterical outburst. “Come below, into the cabin. It is important that we should know everything as soon as possible.”

“This way,” said Ned, stepping toward the stern.

But Jack paused.

“An attempt was made to ram the Vagrant to-night,” he said, “by a queer, but extremely speedy craft. Do you know anything about her, Ned?”

“Do I know anything about her?”

A quaver of indignation injected itself into Ned’s voice.

“Well, I should say so,” he went on; “that’s the vessel of that scoundrel Herrera, the cousin of the governor of Yucatan, which, as you know, is at present a province of Mexico, but, so far as civilization is concerned, parts of it might as well be in the wilds of Africa.”

Tom had been fidgeting excitedly. The name of Yucatan had called up a swarming crowd of memories of his father, the long missing explorer.

“Had my uncle’s visit to Yucatan anything to do with my father’s disappearance?” he asked.

“Everything,” was the rejoinder, in steadier tones than Ned Bangs had yet assumed. The presence of the self-possessed cousins, and their infectious manner of quiet ability, had braced the unstrung lad up wonderfully.

“It was to rescue your father from——”

“Then he is alive?” burst in Tom, aglow at the wonderful news.

“So there is every reason to suppose,” was Ned’s reply.

Without giving him time to say more, the cousins, having ordered the crew to keep a keen lookout for the speedy “ram” craft and notify them instantly of its appearance, half dragged Ned below, and shoved him into a chair in the comfortably furnished main cabin of the Sea King.

“Now then,” said Jack, “tell us everything, Ned, from the beginning. But first you are reasonably certain that both my father and my uncle are alive?”

“There is practically no doubt of that,” was Ned’s response.

“Then fire away,” ordered Tom, seating himself beside Jack, opposite the still badly shaken Ned Bangs.

“We left New York at the time you know,” commenced Ned, “and cruised for some time in the West Indies, your father. Jack, making stacks of observations and records. We met many interesting adventures, but I’m not going to detail all those now. But, although your father seemed to be immersed in his scientific observations, there were several things unexplained about the Sea King’s equipment.

“In a sort of well amidships was stored the aero-auto with which you had been experimenting before he left High Towers.”

Jack nodded. He knew the wonderful craft had been placed aboard, but had understood it had been taken along for private demonstration purposes.

“You mean the air and land craft driven by the gas generated from radolite crystals?” he asked. “The Flying Road Racer, as we called it.”

“Yes,” rejoined Ned, “I guess that’s it. But I reckon you know more about that than I do since you invented it. Anyhow, the aero-auto, as Professor Chadwick called it, was installed in this well, or pit, amidships, which had evidently been prepared for its reception in advance.”

“And it’s still there?” inquired Tom sharply.

“Still there. Whatever Professor Chadwick intended to use it for, he had no opportunity to try it out before—before what I’m going to tell you occurred. Then, too, I noticed that several chests containing articles whose nature was a mystery to me were stored in a sort of lazaretto under the cabin floor. Whatever their contents, they were evidently too precious for Professor Chadwick to let them out of his sight.”

“Wait a second,” interrupted Tom, “I want to take a look outside.”

In a moment he was back, anti dropped into his place with an “All’s well!”

“Never mind details now. Get ahead to Yucatan,” exclaimed Jack impatiently.

“I’m getting there,” protested Ned, a look of what was almost horror passing over his face at the mere mention of the name. “The storm I referred to before, struck us when we were off the southernmost point of Florida. It was a terror of a rip-roaring hurricane. All we could do was to head up into the mountainous seas and run the engines at a quarter speed. We battled with the hurricane thus for four days, and then MacDuffy, the engineer, came on deck one morning with a white face and the news that the main shaft was cracked. It had been unable to withstand the pressure of the racing propeller every time the Sea King’s stern lifted out of the seas.

“Luckily, the wind had moderated a bit by that time, and we set the try sails. Under these we staggered along at a four-knot gait for what seemed an eternity of time. In reality it was about five days. One morning, when the storm had about blown itself out, the lookout shouted that land lay ahead. Sure enough it did. A strip of gray on the horizon; and I can tell you it was a mighty welcome sight.

“Captain Andrews, our sailing master, announced that the coast was, in all probability, that of Yucatan, and from what he told us of it we could not well have struck a more useless stretch of country to us, situated as we were. But it’s ‘any port in a storm’ said the skipper, and we made for the land, staggering along under our clumsy rig.

“That night we anchored off a wild, desolate-looking coast, without a trace of human habitations being visible anywhere. However, we found a bay which, after careful soundings from the boats, proved to have sufficient depth of water to harbor the Sea King snugly. Here we dropped anchor, and mighty glad we were to have struck a haven at last, I can tell you.

“Next day the chief came to your father and told him that he thought he could clamp a metal collar round the break in the shaft and make it practically as good as new. To our astonishment, Professor Chadwick did not greet the news with any special enthusiasm.

“‘You may as well take your time, Mr. MacDuffy,’ says he, ‘for it is probable that we shall remain here for quite a considerable period.’

“‘A considerable period, sir!’ exclaimed MacDuffy in some surprise. ‘Do you mean to explore yon forsaken land in the interests of science?’

“‘It seems to me, MacDuffy,’ answered Professor Chadwick (MacDuffy told me all this later), ‘that fate has brought me here. A very dear and a very near relative of mine vanished in this part of Yucatan many years ago. When we set out on this cruise I had an idea that perhaps I might undertake to go in search of him, or, at least, to discover some trace of his fate. That accounts for the aero-auto which, as you know, my son Jack and I invented, and also explains those chests which contain several more of our inventions suitable to such an expedition.’

“The Professor went on to say that now that he found himself off the very land which held the secret of Mr. Jesson’s fate, he didn’t mean to leave without making an attempt to solve it. From this determination he was not to be swayed, and the next day one of the boats set him and three of the crew, Abner Jennings, the boatswain; Jack Allworthy, the second engineer; and Ezra Kettle, a Maine man and a staunch seaman, ashore. We watched them from the Sea King as they dragged the boat up on the beach and set off into the jungle, beyond which lay the misty blue outline of a range of huge hills.

“Without the slightest warning, and just as they were about to plunge into the thick brush, the mangroves and scrub vegetation parted, and a score of savage-looking Indians rushed out. We saw your father and the others try to parley with them, and then, before we could even train a gun on the scene, the thing happened.”

He paused for an instant, overcome by the recollection of that tragedy on the Yucatan beach. Immediately Jack jumped to his feet.

“I’ve forgotten the ‘enemy’ outside. Hold on a minute,” he called as he dashed away to the deck. “The watch may be all right,” he continued, when he returned, “but there’s nothing like one’s own eyes. Go on, Ned.”

“Poor Kettle went down, transfixed by a spear in the first few seconds after the encounter. Professor Chadwick’s intention had merely been to reconnoitre in preparation for an expedition later on. Not expecting trouble, none of the party was armed. Allworthy dashed back to the boat and seized up an oar. He did valiant service with it before he, too, was felled by a spear-thrust. In the meantime, Professor Chadwick and Abner Jennings had been captured, notwithstanding their stout resistance. Then they were dragged off into the jungle, while we stood half-paralyzed with horror at the suddenness and disastrous consequences of the attack.

“The last we saw of your father. Jack, he was motioning back to us to put out to sea. Brave to the last, he thought of us before himself.”

Ned stooped and placed his hands over his eyes as if to shut out the picture his words called up. Jack Chadwick sat staring vacantly at the paneling of the cabin, not daring to trust his voice to speech. Tom, not less affected, gripped his cousin’s hand.

“Remember, old chap,” he murmured, “that Ned told us some time ago that there was reason to believe that your father was still alive.”

“I’m coming to that,” said Ned, raising his head and proceeding with his narrative.

“It was MacDuffy,” continued the lad, “who organized an expedition to go to your father’s rescue. There was MacDuffy, Captain Andrews, four seamen and myself. The rest were left in charge of the Sea King, the engine-room force having instructions to proceed with the repairs to the shaft, which were really simple enough, consisting only of bolting a collar of metal around the split.

“We were heavily armed, as you may imagine, and after we had landed in the light boat, we stowed it in the brush where it would not be likely to be discovered by marauders. The other boat, the one in which your father landed, had been stove in by those rascally natives. Our first task after this, was to bury poor Kettle as decently as we could. This done, we took up the trail, which was plain enough to follow. In fact, we learned afterward, it was a regular path that the natives followed when they came to the coast after turtles and fish.

“Danger? Well, we knew we were going into a desperate game, but, as MacDuffy said, we couldn’t do otherwise than our best to rescue your father. As we made our way through the jungle we discussed the situation. It looked black and no mistake. In the first place, as Captain Andrews pointed out, the revolution was raging in northern Mexico, and Diaz, in his last desperate stand, had withdrawn troops from every province in Mexico. Captain Andrews told us that the descendants of the Mayas, who inhabited this part of Yucatan, were endowed with a fierce hatred of Mexicans and white men in general, and that they had been kept in subjugation solely by the presence of large bodies of troops. With this menace to their warlike ideas withdrawn, the Mayas were probably ripe for any mischief.

“All this, as you can imagine, didn’t tend to raise our spirits, and the prospect of rescuing your father began to seem remote indeed. Well, to cut a long story short, we followed the trail for two days till we began to arrive in the foothills of the range we had seen. Occasionally we came across what were evidently the sites of recent camps, so we knew that we were on the track all right.

“The third day, about noon, we marched right out of a canyon, threaded by a swift river, into an Indian settlement. Before we could say ‘knife,’ or raise a weapon, we were surrounded and made captives. We were thrown into a palm-thatched hut and placed under strict guard, and we faced the prospect of a speedy death. But at the moment we thought little of these matters, for the hut already contained three other captives, and they were Professor Chadwick, Abner Jennings and Jack Allworthy, the last wounded in the shoulder by the spear thrust that had knocked him down, but luckily not seriously.

“You can guess how delighted we were in the first few moments, and then how depressed we all became as we began to realize that so far as an escape was concerned we might as well have been imprisoned in an iron-walled dungeon. We were deprived of nothing in the way of food, and were not bound in any way, but the hut was surrounded by too strong a guard to make any idea of escape practicable. So the night passed, a night that we spent in discussing and rejecting a hundred plans of escape, for each, in turn, was discarded as hopeless.

“But, although we did not realize it, freedom for some of us was close at hand. Shortly before noon the sky became black as night. A screaming sort of wind arose, and suddenly we felt the ground under our feet beginning to rock. It didn’t take us long to catch on that the disturbance was caused by an earthquake of uncommon severity. The natives began to howl and yell, and rushed about like madmen. That wind suddenly picked up our prison and whisked it off, just as it might have dealt with an umbrella. And there we stood, in the middle of all this commotion, unbound and practically free to go where we would, for the natives were far too busy attending to their own affairs to worry about us.

“In the middle of the uproar and the convulsions of the earth, a whole section of the cliff which upreared itself at the back of the settlement, slid down with a roar like a hundred Niagaras. It caught that village, just as a big rock would smash an anthill. We escaped by the skin of our teeth, but, as it was, we were showered with flying rocks and earth. Luckily, none of us was injured.

“But those poor natives fared otherwise. Of the scores that had been rushing about an instant before hardly twenty remained. One of these was a big fellow, with a beautiful copper-colored skin, clad in a sort of garment made out of jaguar hide. He separated from the rest, and we saw that he carried under his arm a large box, or case, which gleamed dully in the gloom.

“‘He’s making for the canoes!’ shouted MacDuffy suddenly, and then, sure enough, we saw what we hadn’t noticed before in all that hurly-burly, namely, that several dugouts were moored to the river bank. I guess we all caught the inspiration at the same instant. Anyhow, we began running for the bank at top speed. But suddenly that copper-colored giant faced about, and we now saw that he carried a whole quiver full of those poisoned darts that the Maya tribes use with deadly effect.

“Before he could aim one, or shout to the rest of the villagers, who hadn’t noted our escape, Abner Jennings flew at him like a wildcat. Down he went, bowled over like a ninepin, under a crashing blow from Jennings’ fist.

“‘Hurray, lads! Now for the boats!’ shouted Allworthy, and we scampered after him toward them. But at that instant a queer thing happened. A man came racing toward us from amidst the ruins of the village.

“‘Get him!’ yelled Allworthy savagely, as Jennings stooped and picked up a big rock.

“But the next instant his hand dropped to his side. The man was white! In spite of his half-naked condition and sun-browned skin, it was clear enough that he was as much of a Caucasian as any of us, and then came the wonderful part of it all.

“‘In the name of heaven, white men, stop!’ he shouted, ‘take me with you. I am——’”

“Jasper Jesson!”

It was Tom Jesson who had uttered the exclamation. In a flash of intuition he had seen what was coming before Ned uttered it. The lad literally quivered with excitement as he spoke.

“Right. It was your father, Tom,” rejoined Ned. “Professor Chadwick stopped, ran back and embraced him. For a minute we all stood stock still, rooted there by sheer amazement, I guess. Well, we got to the canoes and set out down the river. There were four dugouts, and the way they dashed down that stretch of water was a caution. No need to paddle. The current just tore along for several miles. I don’t see how it was we didn’t upset, but the fact remains that we didn’t. Pretty soon we reached a part of the stream where another flowed into it, and it broadened out and grew calmer.

“Then, for the first time, we felt free to talk. We hauled the canoes ashore and camped while we discussed plans. But first, you may imagine, we heard Mr. Jesson’s story. He had been captured by the tribe who had trapped us, soon after his arrival in the country. And their prisoner he had remained since. Undoubtedly he would have been put to death, but he had by great good luck managed to translate some cryptograms carved in the marble stones of some ruins in the mountains, and after that they looked on him as a sort of god. At any rate, he was well treated, but given no chance to escape. The earthquake that had set us loose had proved his opportunity, too. Of course, it’s no use my trying to give you any idea of his delight and astonishment at finding his brother-in-law and getting news of you, Tom, and of the old home.

“He had just about concluded his story, when Mr. Chadwick drew from under his coat that same metal box that we had seen the big copper-colored fellow skedaddling with. He had taken it from the chap as he lay stunned, rightly guessing that it was of immense value. But he was far from surmising what it was he had really discovered, till a few moments later.

“‘Maybe, Jesson,’ he said, ‘you can tell me what kind of a box this is. It’s silver, all right, for one thing, but it’s covered with some sort of picture writing, too, and——’

“But Tom’s father interrupted him with a shout.

“‘Good heavens, man!’ he exclaimed, ‘you’ve got hold of the holy of holies of the Zakaks,’——that’s the name of the tribe that had hooked us.

“While we all looked on with open mouths, Mr. Jesson broke a long thorn off a prickly bush growing near at hand and shoved it into a small hole in the front of the box. The lid flew open, and there inside was something that made us blink our eyes,—a blood-red stone, a blue one, and a gorgeous green gem.

“We all caught our breath, I can tell you. Each stone was as big as a pigeon’s egg, and it didn’t take an expert to tell that we had before us a ruby, a turquoise and an emerald that had, probably, not their equals in the world.

“Then Mr. Jesson told us how the tribe had a legend that those stones were brought from some, mysterious land beyond the seas by their fore-runners, and that if they were stolen or lost disaster would overtake them. At certain phases of the moon, he said, the stones were worshiped with all sorts of queer rites that he had not been permitted to witness.

“We, none of us, could guess what they were worth, but it was a safe estimate that they represented a snug fortune. As for the box itself, it was, as I said, of dull silver, with three sort of oval bosses or bumps on its cover. These were of a reddish color, and were evidently of no value except as ornaments. After some more talk it was decided to make for the Texan coast, and as soon as we had regained the yacht, get into wireless communication with you lads.

“Professor Chadwick explained that he had had a half-formed intention of attempting to find Mr. Jesson before he left America, and for that reason had sent you boys to Lone Island so that he might notify you of his success by wireless as soon as possible, without letting the general public know, and also have you handy in case of an emergency.”

“So that explains Lone Island,” struck in Jack, “but go on, Ned. I can hardly wait for the rest of your story.”

“Neither can I,” added Tom; “but aren’t you fellows surprised that we don’t hear anything from outside?”

“It is strange,” agreed Jack. “I’ll run up again soon.”

“Well,” continued Ned, “we knew that by following the river we must emerge on the coast, probably near to the spot where the yacht was anchored. We therefore lost no time in re-embarking and getting on our way once more. Luckily, there was some food, bananas and dried flesh of some animal,—deer, most likely,—in the canoes, which must have been provisioned for a trip. So that night, when we camped, we had a good supper, with something left over for the next day.

“We slept under the canoes, turning them keel up to form a protection from the dews, and also from any prowling animals. The spot we had chosen was well back in the brush, so that in case of pursuit we had a good hiding place. But we slept without interruption, taking watch in turn. The next morning, before it was well light, we set out down the river again, and that afternoon we had reason to think we were close to the coast. The character of the jungle on either side of the river changed and the stream grew wider and more sluggish.

“So far we had had no indication that we were not the only human beings in that part of the country, so you can imagine our astonishment when, about mid-afternoon, on rounding a bend in the stream, we beheld a squat, drab-colored craft, without spars or funnel, moored to the bank. It didn’t need a second glance to tell us that she was a fighting craft of some kind. On her decks were the outlines of several rapid-fire guns shrouded under canvas covers. Her bow was shaped like a ram, and we could see by the rows of rivets along her sides that she was built of steel.

“‘That’s one of the new shoal-draft, gasolene gunboats, built for the Diaz government at the Vulcan yards in Charlestown,’ declared Professor Chadwick at once.

“He had hardly spoken when several of the crew, who had been lounging about the decks, saw us coming. There was an instant stir on board the ugly-looking craft, and presently the figure of a small, dark-skinned man, with a black, pointed beard and moustache, and heavy, sinister eyebrows, appeared on the bridge, which was just forward of a sort of conning tower.

“He wore white garments and a broad-brimmed Panama hat. As soon as he appeared he hailed us.

“‘Come alongside, gentlemen,’ he said, using almost perfect English. ‘I welcome you to El Tarantula.’”

“A few moments later,” continued Ned, “we were standing on the deck of the sinister-looking craft, confronted by her equally sinister-looking owner, for such we soon found he was, in fact, if not in name. From him we speedily learned that not only was he the governor of that part of the province of Yucatan, but that he also controlled large plantations near the mouth of the river. The principal produce of these was sisal hemp, a well-known and valuable product of the country.

“Naturally, we supposed that as soon as we had told our story, the first act of Ramon Herrera, for such he informed us was his name, would be to aid us in reaching our yacht. But the event proved exactly to the contrary.

“‘You will take up quarters for the present on my yacht, gentlemen,’ he said, in a tone almost of command.

General Herrera, commander of El Tarantula, the Mexican gasolene gunboat.

“Professor Chadwick started to protest, but met with a stern interruption.

“‘My country is in the throes of a revolution,’ Herrera said, ‘and at the present time it is unknown to me whether your United States of North America is involved in the trouble or not. It is my belief, and that of many of my countrymen, that the massing of troops on the Texan border, by orders of your President Taft, is a menace to the Diaz government, and an encouragement to the revolutionaries. This being so, you must regard yourselves as my guests,—I will not use an uglier word,—till such time as I receive further advices. Furthermore, I do not mean to make any secret of my dislike for meddling Yankees.’

“‘Sir,’ exclaimed Professor Chadwick, ‘you are deliberately insulting.’

“‘Senor Yankee,’ was the calm reply, ‘you have deliberately intruded yourself into a country where you and your inquisitive countrymen are not wanted.’

“‘I am not aware by what right you dare to assume such an attitude toward us,’ resumed Professor Chadwick, now thoroughly aroused, and, indeed, we were all at the boiling-point, as you can imagine. Herrera’s every word seemed to be a deliberate taunt.

“‘I assume my attitude, as you call it, by right of might,’ was the cold reply, ‘my ancestor. General Jose de Guzman Herrera, was slain by your Yankee soldiers in the Mexican war. Judge, then, if I have any reason to favor Yankees.’

“‘You are likely to pay dearly for this forcible detention of peaceful citizens of a republic at peace with your country,’ warned Allworthy.

“Herrera shrugged his shoulders.

“‘I’ll take my chance of that,’ he said, ‘besides, as I remarked before, I am not so certain that my country and your country are not by this time at war.’

“Well, there was nothing more to be said, and determined to make the best of our situation we went docilely enough to the quarters that Herrera had provided for us, which consisted of three cabins in the extreme stern of the ship. Captain Andrews, MacDuffy and I were thrust into one cabin, your father and Mr. Jesson into the next compartment, and Abner Jennings and the two sailors into a third stateroom.

“Here was a pretty kettle of fish, and a fine ending to our hopes of reaching the coast, which, we were confident, was not far distant. From scraps of conversation we overheard, for there were gratings above each stateroom door, we learned that the Tarantula was tied up to the shore bordering on one of Herrera’s plantations. We heard later that the slaves,—most of them Mosquito Coast negroes illegally impressed as slaves,—had made some trouble, and that Herrera was here with his armed craft to suppress the uprising by stern means. What these means were we found out later, and without going into detail, we heard enough to know that the monster,—as we subsequently found him to be,—spared no form of cruelty to browbeat his luckless servitors into submission. All this was translated for us by Captain Andrews, who spoke Spanish fluently.

“We might have been confined in our narrow quarters for an hour, or it might have been longer, when we heard the door of the adjoining stateroom unlocked, and presently voices came to us through the grating. It was easy to recognize Herrera’s tones as he cross-examined Professor Chadwick. One of the Mexican sailors had noticed that when the professor came on board he had slipped a silver chest—the treasure box—under his coat. The fellow had informed Herrera, and now that arch-scoundrel was demanding that Professor Chadwick and Mr. Jesson submit to being searched.

“I can tell you we exchanged blank glances when we overheard this. It seemed pretty tough that, after all we had gone through, we were to be robbed of what was bound to prove a substantial reward, for Professor Chadwick had insisted that we agree to take an equal share with him having participated in his dangers.

“But to our astonishment the search evidently resulted in nothing being found. For before long we heard Herrera bursting out into Spanish oaths. He wanted to know what had become of the box.

“‘If you had asked me before,’ Professor Chadwick replied, ‘I would have told you. I threw it overboard rather than let it fall into your hands.’

“We listened for an outburst or worse right then. But none came. The rascal, in whose power we were, evidently didn’t know the value of the silver box, for he merely remarked that Professor Chadwick’s act would not improve our situation, and left the cabin. But we, in the adjoining stateroom, again exchanged blank glances. It was no joke to think of that fortune in magnificent stones being consigned to the muddy depths of that Yucatan stream.

“A short time after Herrera left the cabin, however. Professor Chadwick climbed up on a bunk in his stateroom, and placing his lips to the grating informed us that he had not, in reality, hurled the box overboard, but that it was suspended outside the porthole of his cabin by a fine bit of cord which he had happened to have in his pockets. The porthole was beneath the overhang of the stern of the gunboat, and unless any sailor went prying about under the vessel’s counter there was not much likelihood of its being discovered. The Professor informed us also that he was determined not to purchase our liberty at the price of the precious stones.

“‘This is the twentieth century,’ he said, ‘and I refuse to believe that this rascal, for such Herrera has shown himself to be, will dare to hold captive free American citizens for any length of time.’

“We agreed with him in this, but MacDuffy, who, as an engineer, possessed with an investigating turn of mind, still busied himself, as he had since the moment of our imprisonment, with trying to find some means of escape. There was a nine-inch porthole in our stateroom, and also in the other two. But, of course, this offered no opportunity for escape. By peeping out through it, however, we could see that our dugouts had been attached to the stern of the Tarantula by a line. If we could only reach them we might be able to attain freedom.

“All at once MacDuffy uttered an exclamation. He had discovered that under the porthole was a square plate, bolted into the stern frames, and seemingly devised, when removed, to permit of a gun being thrust through the opening. The nuts which held the bolts in place were inside the cabin, and MacDuffy produced from his pockets a serviceable-looking monkey wrench, which was the engineer’s constant companion.

“‘I’ll undertake to have those nuts unscrewed in half an hour,’ said he in a low, excited tone, ‘and then what’s to prevent us dropping through the stern to-night, hooking the dugouts and floating down to the coast?’

“What indeed? we thought. The plan looked feasible enough. But, naturally, we did not, for a minute, countenance the idea of making good our own escape and leaving the rest to their fate. But Professor Chadwick, when we communicated our plan, decided at once that we must make the attempt that night, and, if we succeeded in reaching the coast and the Sea King, must summon help.

“After a lot of persuasion we agreed to do this. Then we waited, with as much patience as we could muster, for the night to fall. Food and drink was brought us at dusk, and we ate all we could, knowing that we might have strenuous work before us. After dark MacDuffy fell to work on the bolts. It took scarcely an hour to loosen them. This much accomplished, we waited till all grew quiet about the Tarantula, which was not before midnight.

“Whispering a good-by to Professor Chadwick and Mr. Jesson, we dropped through the opening, after MacDuffy had removed the plate which left a hole some four feet square. The rope by which the dugouts trailed astern was just above our heads. Captain Andrews seized it and pulled the first of the frail craft toward the Tarantula till it was under the opening we had made. Then they told me to drop down as silently as possible. When I was on board MacDuffy followed, stuffing his wrench into his hip pocket, and last came Captain Andrews. Before we cut loose we, according to Professor Chadwick’s instructions, cut the string by which the jewel casket was suspended, and stowed it safely on board the dugout.

“This done, I cut the painter with a slash of my knife, and the dugout drifted silently off down the current into the darkness. Our escape had been made in safety. We reached the coast, and after paddling northward for half a day, sighted the Sea King. All was as we had left it, and mighty glad every one was to see us. I can tell you. But the plight of Professor Chadwick, Mr. Jesson and the rest, cast a gloom over us all.”

“Tell me,” begged Tom, interrupting again, “are they still on the Tarantula?”

“I don’t know,” replied Ned.

“Well, hurry your story,” exclaimed Jack. “We must go to their rescue wherever they are!”

“Captain Andrews lost no time in ordering me to the wireless,” continued Ned hastily, “and as we steamed northward I kept pumping away at my key. At length, as you know, I got into communication with you. But as I did so there was a sharp and sudden shock through the Sea King, and she came to an abrupt stop. That shaft had parted again. There was nothing for us to do but to anchor. At almost the same time one of the crew shouted that a craft resembling the Tarantula was on the southern horizon and overhauling us fast. It didn’t need a second look to show us that the strange vessel was indeed the Tarantula. As she drew close to us there was a flash and a puff of smoke from her bow, and ‘crash!’ our aerials parted,—shot through at the foremast.

“There we were, crippled and helpless, and I didn’t even know for sure if my message to you was clear or no.”

“One question,” put in Jack, “has the Tarantula a wireless?”

“Yes; I meant to tell you about that. She is fitted with a collapsible military mast, and, from what we overheard, Herrera has a complete plant at his plantation ashore likewise.”

“That disposes of X. Y. Z.,” said Jack, glancing at Tom. “It’s plain enough now that some one ashore intercepted our message, just as we caught theirs, and flashed it to Herrera.”

“Guess you’re right,” agreed Tom gloomily, “and we are responsible for giving away the exact location of the Sea King.”

“How’s that?” asked Ned, in a wondering tone.

“I’ll explain all about it later,” said Jack, “the thing is now to formulate some sort of plan to get out of this tangle. Is Captain Andrews or Chief MacDuffy about?”

“MacDuffy is below, trying to fix the break in the shaft,” was the response. “Captain Andrews is asleep in his cabin. He was worn out, and I didn’t wake him when our rocket signals were answered by you.”

“Well, I think we’d better rouse him now,” Jack was beginning, when the cabin door was flung open and a sailor, whose face was chalky beneath his tan, burst in. The group at the table looked up, startled and alert. Ned’s narration had taken almost an hour, and although they had not forgotten the dangerous proximity of the Tarantula, they had had no way of guessing in what way their enemy would next become active.

“That yaller-faced Greaser’s craft is bearing down on us. Mister Bangs!” exclaimed the man. “She looks as if——”

There was a sharp crash overhead, and the booming detonation of a gun resounded an instant later. The boys sprang to their feet and scrambled up the companion way, headed for the deck.

As they went Jack flashed a swift word to Ned.

“You say that the chests my father took such care of are still in the cabin?”

“Yes; in the Professor’s stateroom.”

“Good. I’ve a notion they contain something that may prove valuable to us right now. Open them up and see if one of them contains some queer-looking guns. If it does, bring the weapons on deck right away, and—summon Captain Andrews.”

Ned retraced his steps and Jack ran swiftly up after Tom. On deck they found the sailors running about distractedly. The shot they had heard had carried away part of the foremast of the Sea King. The wreckage lay in a tangle, about which the seamen hovered confusedly.

While the boys still stood regarding the scene, hardly knowing for the moment what to do, a stoutly-built man, with an overcoat hastily thrown on over a suit of pajamas, joined them. It was Captain Andrews. The light from the incandescents fell on his bronzed, blonde-bearded face, and Jack felt, as he clasped the newcomer’s hand, that here was a man who could be relied on to the last ditch.

“Ned Bangs told me I would find you here,” he said. “I hastened on deck right away. I should have been out and about long ago; but——”

“That’s all right, captain,” spoke Jack swiftly, “you had earned your rest and no mistake. The thing is, what are we going to do now?”

“The rascal Herrera has attacked us, Ned told me.”

“Yes. His craft is in the offing now. He has shot away part of the foremast. The riding-light on it must have acted as a target for him.”

As the lad spoke a voice came cut of the darkness:

“We want that silver casket. Are you going to give it up peaceably, or do we have to blow your vessel out of the water?”

“You infernal scoundrels!” shouted Andrews, before Jack could check him.

The captain bounded forward to a machine gun. With quick, nervous fingers he was ripping off its cover when Jack laid a hand on his arm.

“Hold on a minute, captain,” he said, “I’ve another plan. We shall know in a few seconds now if it will succeed.”

The captain looked at him wonderingly.

“They outnumber and outarm us,” he began. But Jack broke in:

“I’ve an idea that one of those chests in my father’s cabin contains some novel weapons,” he said, “a new kind of gun, the invention of Tom and myself. They contain a magazine of shells loaded with a gas which will paralyze any form of animal life with which they come in contact.”

The captain gasped.

“Well,” he said, “I’d heard that you kids were inventive wonders, but this——”

“Oh, we didn’t invent the gas,” interposed Tom, who had been an interested listener to Jack’s last words, “Professor Chadwick did that. But we applied it to use in the guns.”

“And they work?”

“Well, we’ve tried them on rabbits and small game, and brought down whatever we aimed at. You see, the shells are loaded with this gas in a semi-solid form. When the gun is fired a fuse is lighted, which releases the gases, and they fill the atmosphere, surrounding anything they strike with a vapor that causes temporary helplessness.”

As Jack spoke there came another hail out of the darkness.

“We are waiting. Resistance is useless. We know you have that casket with you. What is your answer?”

“Will you give us a few moments to consider?” shouted back Jack.

A pause followed.

“I wonder how on earth they know that Ned and the rest secured the casket?” wondered Tom.

This was a poser. It was not till long afterward that they found out that, following the discovery of their escape from the Tarantula, a sailor had noticed the severed string hanging from the porthole of the Professor’s cabin prison. Herrera’s keen mind at once guessed the purpose it had served, and also surmised that the casket must be very valuable. Professor Chadwick, on being questioned, admitted,—thinking of course that the Sea King was by that time out of danger of pursuit,—the manner in which he had tricked the Mexican and the contents of the box.

Suddenly, out of the darkness, ranged the ghostly outlines of El Tarantula. Hardly twenty-five yards separated her from the Sea King. She was moving slowly, far below her usual swift motion. Her dash from the mainland had resulted in overheated engines, which accounted for the space of time those on board the Sea King had been free from her presence.

“We’ll give you five minutes and no more,” came a voice from her midships.

“Good,” murmured Jack, as he heard the terms of the armistice, “that ought to be plenty of time and—Oh, glory be!”

Ned had come on deck while the young leader was speaking. In his arms he carried a collection of as strange-looking weapons as were ever seen outside of a museum. Yet they represented a type of gun destined to become famous.

“Hurray!” muttered Tom under his breath, “they’re the gas-guns, sure enough.”

While Captain Andrews’ eyes fairly bulged. Jack took one of the guns. They were of a dull colored metal, allowing no light to glint from any bright surfaces. A barrel about three and a half feet in length, terminated in a cylinder of greater diameter than the barrel itself. This was a muffler, which effectually silenced the sound of the spring that was used to send the gas globes on their way and snap the fuses. The stocks of these odd firearms, if such they could be called, were large, and contained sixteen “gas globes”—spheres of a tough and glutinous kind of gelatine, filled with the destructive gas—a compound of ammonium nitrate,—in a semi-liquid form.

“How do you fire them?” asked Captain Andrews.

“Handle them just as you would an ordinary gun,” rejoined Jack. “The globes will burst when they strike the Tarantula and spread the gas they contain broadcast. Luckily, the craft is to leeward of us, or we might be in danger of getting a dose of our own medicine when the gas globes detonate.”

“Will the gas kill them?” asked Captain Andrews, in such a vindictive tone that Jack couldn’t help smiling.

“Hardly,” he said; “but it will take the fight out of them for a while, I imagine.”

Acting under the lad’s instructions. Captain Andrews summoned some of the interested sailors to him. There were twelve of the guns “and a chest full of ammunition below,” whispered Ned.

Eight of the men were given a gas-gun each. Their faces expanded in grins as they learned the nature of the novel weapons.

“First time I ever heard of knocking a feller out with a gas pill,” said one of them in an undertone.

The serving out of the gas-guns had hardly been completed when the voice from the Tarantula hailed them again:

“Five minutes is up,” it said; “we’re going to board you.”

At the same instant the Tarantula began to range in alongside. Evidently those on board her did not fear resistance, for as she drew closer her decks blazed with light, and those on board the Sea King could see that her machine guns were trained full on the yacht.

Under Jack’s orders the armed portion of the Sea King’s company had dropped behind the bulwarks, aiming their guns through scupper holes. Thus, of course, all that was revealed to the enemy was a group of flurried-looking sailors standing about the wreckage of the mast forward. Hardly ten yards separated the two vessels when Jack gave the whispered command: “Fire!”

What followed, so Tom described it afterward to the author, “was like watching a moving picture.”

There was no sound as the triggers on the gas-guns were pulled, but as the collapsible globes struck the Tarantula’s decks and superstructure and burst with a soft, pattering sound, her crew began to roll about like drunken men.

As the stupefying vapors impregnated the air with their fumes, one after another the men began to drop like flies. The resistance of the stoutest didn’t endure for more than a space of five minutes. Herrera himself, the last to succumb, fell beside the wheel house as he was shouting at the helmsman to withdraw from the infected air.

The young inventors’ wonderful gas-guns had received their first real test, and had surely not been found wanting in efficiency. The Tarantula, a few moments since the scene of feverish activity, now lay a drifting hulk. Her engines were still slowly revolving, but there was no hand to govern them. Several of the gas globes had been aimed at the engine-room hatches, which were open. Deflecting thence they had burst into the machinery space, stupefying the force at work there.

The victory was complete and sweeping.

“Well, what next?”

It was Tom who spoke, and his voice broke the spell that had held all hands as they gazed at the silent craft drifting away from them into the darkness.

“We must overhaul the Tarantula and set my father and yours free, Tom, if they are still there,” came from Jack.

“A good suggestion; but how are we to do it?” inquired Captain Andrews, who was not aware of the readiness of the Vagrant to be placed in active service at once.

“We’ll board the Vagrant. At the pace that spider-craft is going it won’t take long to lay alongside her,” decided Jack.

Before many minutes had passed Jack, Tom Jesson and Ned were on board the Vagrant. Jupe, much against his wishes, was left behind on the Sea King.

“Ah’d hev liked jes ter hev one good, big kick at dat Mexican tamale,” he argued; but it was decided to go without him.

The Vagrant’s engines, despite the recent strain placed on them, were found to be working perfectly. Amidst a shower of good wishes from those left on board the Sea King, she moved off into the darkness in pursuit of their recently vindictive enemy. As Jack had foretold, it did not take long to overhaul the craft with which Herrera had hoped to intimidate those on board Professor Chadwick’s yacht.

It gave the boys a somewhat uncanny sensation as they stole silently alongside the slowly moving Tarantula, and then made fast by throwing a grappling iron on her decks. This feeling was not changed when, clambering on board, they gazed on the decks strewn with senseless forms, lying as they had fallen. They appeared to be wrapped in deep, dreamless slumber. The gas had operated on them much as if they had been patients in a hospital under the influence of an anæsthetic.

Stopping only to make sure that all on board were dead to outward impressions for an hour at least,—after which time Jack calculated they would begin to stir,—the trio of lads made no more delay about seeking out the stern cabins, in which, they believed. Professor Chadwick and the rest were confined.

Jack was the first to make the alarming discovery that the staterooms which had been the scene of their captivity were empty.

It was a bitter pill to swallow indeed. The boys, perhaps despite their better judgment, had confidently calculated on finding and delivering their friends. Now, however, it appeared that they were as far from accomplishing this as ever.

“There’s only one conclusion to draw,” said Jack at length. “Herrera, for reasons best known to himself, has left them some place ashore.”

“Unless he——” began Ned, but Jack cut him short.

“I guess even Herrera wouldn’t dare to go much further than that,” he declared stoutly, “the question now is,—where has he left them?”

“Judging from the speed with which he overtook the Sea King he could not have proceeded far from the spot where we first encountered the Tarantula,” decided Ned, “according to my ideas then, our friends have most probably been set ashore on his plantation.”

“Cracky! I believe you are right, Ned,” cried Tom in a jubilant tone.

His voice became more sober the next minute, though.

“In that case they will be under a strong guard,” he added despondently.

“I don’t see that that follows,” struck in Jack. “I’ve just been thinking that Herrera, judging from his large crew, must have most of his fighting men right here on board the Tarantula. In such a case, the ones left at the plantation can’t be much more formidable than those slaves Ned told us about a while back.”

“That does sound reasonable,” assented Tom, “so then it will be our best plan to make for the coast at once. Do you think you could find the mouth of that river again, Ned?”

“Captain Andrews has its exact bearings,” rejoined the “wireless” lad. “I guess we could pick it up with no more trouble than we’d have in making any other port.”

“That sounds good,” gleefully exclaimed Jack. “I reckon it will be our best plan of action, too.”

“More especially as Herrera and company are going to have bad headaches when they do wake up, and will take some time to get their wits together,” said Tom with a grin. “By that time, if all goes well, we ought to have secured the freedom of our party.”

“Jove! But there’s one thing we were almost forgetting,” cried Ned suddenly.

“What’s that?”

The question proceeded from Tom.

“This craft has wireless. When the bunch comes back to life they can flash a message to the plantation telling them to be on the lookout for us. That is, if they guess where we’ve gone, and there isn’t much doubt that they will.”

“Right you are, Ned Bangs,” agreed Jack; “but I guess with what we know about wireless it won’t take over and above long to fix the Tarantula’s apparatus so that it won’t be any more good than a bunch of junk.”

“Seems a shame,” commented Tom.

Jack and Ned stared at him.

“Yes, and it would have been a shame if Herrera had sent the Sea King to the bottom, as he fully intended to do,” indignantly exclaimed the latter. “I don’t see where he comes in to be entitled to any more consideration than a rattlesnake.”

“No more do I,” assented Jack. “Come on, let’s find the wireless room of this craft and get busy with it.”

It took but a few minutes to locate the wireless room of the speedy gunboat. It took still less time for Jack to sever the wires and render the condensers and helix useless.

“There,” he said, with a deep breath, as he concluded his task, “I guess it will be quite a while before any messages can be flashed from this craft.”

“Unless they have extra apparatus on board,” came from Tom.

“Gee whiz! That didn’t occur to me. Wonder if they have?”

“Well, we can’t waste time looking for it,” struck in Ned. “You said the effects of that gas would wear off in about an hour, didn’t you. Jack?”

“Yes.”

“Then I suggest we get a move on.”

“Right you are,” agreed Jack, and then, looking around for Tom, he missed him. The lad had slipped silently out of the place.

“What can have become of him?” gasped Jack, somewhat astounded at Tom’s quick disappearance act.

It was not till they emerged on deck a few seconds later that they heard sounds from the engine-room, and presently Tom showed up. He had a wrench in his hand, and bore a well-satisfied grin on his round face.

“What on earth have you been up to?” asked Jack.

“I’ve been administering much the same treatment to the engines of this craft that you have to the wireless,” chuckled Tom. “Gee whillikers! what an astonished outfit of tamale-eaters there’s going to be on this ship when they come to life!”

Leaving the Tarantula to drift at her sweet will, all haste was made by the youthful adventurers in regaining the side of the Sea King. When they reascended to the deck of that craft, after making fast the Vagrant, they found a newcomer among the crew to greet them,—namely, MacDuffy, the engineer, who announced that he had made temporary repairs.

“But they willna be lastin’ lang, I’m thinkin’,” he said ruefully, “I dinna ken if they will carry us a hundred miles.”

“And it’s a good three hundred or more back to that river mouth,” cried Ned in dismay.

“Aye, lad, it wull be all of that,” agreed the Scotchman.

A sudden idea struck Jack.

“Is there any one on board who understands wireless besides Ned Bangs?” he asked abruptly.

Sam Serviss, a youngish-looking seaman,—he was third officer of the Sea King,—stepped forward.

“I can read Morse and Continental,” he said simply, “and I’ve taken lessons from Ned Bangs here. I guess at a pinch I could operate a wireless all right.”

“Good. That puts my plan on a feasible basis,” exclaimed Jack.

“What may the plan be?” asked Captain Andrews interestedly.

“Just this: The Sea King will proceed to Lone Island, navigated by Mr. Serviss here. On the island, as you know, is a wireless plant. The generator is not a very powerful one, but you can harness the island apparatus to the generators of the Sea King, and obtain as much current as you want,—two kilowatts if necessary. I have a plan to increase the power of the Vagrant’s outfit, so that we can keep in touch with you.”

Captain Andrews and MacDuffy nodded. Jack went on, while they all listened with deep attention.

“The Sea King carries a gasolene launch. On arrival at Lone Island you can try to get into communication with us. In the meantime the launch can be despatched to Galveston for the supplies and tools needful to mend that shaft properly. This being done, Mr. Serviss will watch the wireless for further instructions, or, in case of need, proceed to our rescue.”

“Then you mean to go back to Yucatan the noo?” inquired MacDuffy.

“Of course,” rejoined Jack, quick as a flash, and in a tone that showed he had indeed arrived at a definite conclusion in the matter. “It’s my duty and Tom’s to rescue our relatives, and that as soon as possible.”

“And you’ll no be countin’ on taking me?” asked MacDuffy, rather piteously.

Jack shook his head.

“The capacity of the Vagrant is limited, Mr. MacDuffy,” he said, “and we may have to adopt another means of transportation before we get through—I mean the aero-auto.”

“Good. The very thing,” was Ned’s enthusiastic comment.

“I guess Captain Andrews, Tom, Ned, Jupe and myself will be a big enough force to take along,” went on Jack; “of course, we’ll carry the gas-guns and a supply of ordinary firearms and ammunition.”

The boy’s plans were so clear and well-defined that there was no opposition. By this time the sky was streaked with gray and rose color in the east, and a wan light overspread the sea. It showed them the faint and distant outlines of the Tarantula, drifting seaward in the clutch of some strong ocean current. Evidently, then, they had nothing to fear from that source.

The work of hoisting the aero-auto from its well on the Sea King, and transferring the odd land-and-air traveler to the Vagrant was set about at once. Blocks and tackles were reeved on the derrick boom of the after mast of the Sea King, and with wondrously little effort, the vehicle the Boy Inventors had evolved was transferred to the flush after deck of the Vagrant, where it was lashed in place, the ropes that bound it being affixed to ringbolts on the deck.

The Flying Road Racer must be described in some detail here, as it is destined to figure largely in after events of the Boy Inventors’ lives. The auto part of the wonderful machine, then, was a cigar-shaped affair of aluminum, with four wheels of the “disc” type. It was fitted much like an ordinary auto, with padded seats in front and in the tonneau, equipped with shock absorbers, and was twelve feet in length.

In the front of the car the engine, a hundred horse-power, eight-cylinder, four-cycle machine, was installed. The controls led to the steering wheel, just as is the case in ordinary cars. The crank shaft, however, projected through the front of the car, and was provided with a slotted terminal, by means of which an eight-foot aerial propeller, carried in sections in the car itself, might be affixed at will.

Above the main body of the car was a light, but strong, framework supporting a balloon bag,—also cigar-shaped, and of the finest oiled silk,—of a capacity of about fifty thousand cubic feet of gas, and with a theoretical lifting power of forty-five hundred pounds. The method of inflating this bag at will, and thus converting the auto into a practicable dirigible, was the most startling innovation about the invention.

The body of the car, as has been said, was cylindrical, with sharp ends, like a mammoth perfecto cigar. This cylinder was divided in half, longitudinally, by a floor of aluminum alloy. The entire lower chamber thus formed was a big generating tank for a gas having a lifting capacity exceeding hydrogen vapor by a ratio of three to one. This gas was generated from brownish crystals formed of a compound of hydrogen-saturated alum and another chemical akin to radium, which the boys, for the present, kept a close secret.

Two pounds of these crystals, when forty gallons of water were added to them, formed close to sixty thousand cubic feet of the powerful inflation gas. One hundred pounds of the crystals were carried in a special compartment of the aero-auto, and constituted an ample supply for all emergencies. To inflate the bag, then, all that had to be done was to unbolt a metal hand-hole in the floor of the front section of the car. Through this the crystals were dumped into the tank beneath and the water added. The opening of the generator was then closed and clamped down tight, hermetically sealing the tank. The gas, under compression, was explosive, and was utilized to run the motor as well as for inflation purposes.

Immediately in front of the operator of the car was a gauge showing at all times the pressure in the tank, and when the gas bag was in operation the amount of gas in that also was indicated. When sufficient gas was generated, the operator turned a valve and the gas from the tank instantly began rushing into the bag carried on the framework above him. The bag was so folded that it inflated without necessitating much attention. Three broad bands of rubberized fabric of great strength encircled the gas bag proper.

To these were attached wires of a tensile strength exceeding anything hitherto known. The other ends of the wires, of course, were fastened to the body of the aero-auto, so that when the bag was sufficiently buoyant the entire car and its occupants were borne aloft. By means of an exhaust pump connected with the motor, the volume of gas could be reduced at will, causing the entire aero-auto to sink at the pleasure of those directing the machine.

“Astern” of this wonderful invention was a rudder of vulcanized silk and vanadium steel framework, which, when the invention was in use as a land vehicle, was folded. When it was desired to take the air the release of a simple clutch caused the rudder to assume its proper position. At the same time, two long planes could be attached to the sides of the car, to be used in ascending or descending. The machine had two steering and governing devices. One wheel was used for the auto control, and another “tiller” was put in use when it was soaring through the air. The control of the aerial rudder, planes and engine, all centered in this second wheel, thus putting the craft, at all times, under one man—or boy—management. In conclusion, it may be mentioned that the craft was equipped with speedometer, barometer, barograph and patent self-starting devices, doing away with the old-fashioned “cranking” of the engine. The wheels were fitted with semi-solid tires of great size and strength, and the shock-absorbers before mentioned obviated any danger of a severe jar or jounce on landing. The machine had been given several trials at High Towers and had been found to work perfectly.

It is not necessary here to give a description of the loading of the aero-auto, the leave takings, and the final instructions and messages that passed between the Vagrant and the Sea King. Suffice it to say, that at eight o’clock that morning all preparations on both sides were completed and that at eight-ten precisely the two vessels parted company. The Sea King steamed northward slowly, bound for Lone Island, and the Vagrant headed for the mouth of the river on which the plantations of the rascally Mexican were situated. At that time the Tarantula had drifted out of the adventurers’ ken altogether, over the eastern horizon.

Leaving Captain Andrews and Jupe in charge of the Vagrant, the lads, thoroughly exhausted now that the strain and care of the long night were over, sought their bunks and were soon wrapped in slumber. In their dreams they flew high above the plateaus and rugged ranges of the mysterious land for which they were bound, questing the unknown in search of the lost ones.

It was noon of the next day when Captain Andrews announced that they were still some two hundred miles from their destination. But, as the boys were all three of them busy over the aero-auto, adjusting and examining every part of the queer craft, the time flew swiftly. The dawn of the third day found them anchored off the jungle-clad coast, while not a mile from them the waves were breaking on the bar that marked the mouth of the shallow river, which, they subsequently learned, was called the Apak.

It would be two hours, so Captain Andrews calculated, before the tide turned and made the passage of the bar possible. In the meantime. Jack brought on deck the silver chest, which he had, of course, taken possession of, pending the time when he could deliver it to his father. The adventurers spread the three blazing gems it contained out on the deck, and revelled in the glow of light and wonderful inward fires the precious stones revealed as the bright sunlight played upon them.

The Vagrant had once been used as a passenger craft at Galveston, and her former owners had installed an iron safe in the cabin for the protection of valuables. In this receptacle Jack replaced the silver casket after they had examined the gems to their hearts content.

By this time Captain Andrews was ready to pronounce the crossing of the bar at the river mouth feasible. The tide had risen till the tempestuous breakers had subsided into long swells, with a narrow passage of smooth water marking the channel. Carefully following this, the skipper of the Sea King piloted the Vagrant through into the calm water of the estuary beyond.

The boys, grouped forward, gazing at the surroundings with eager eyes, beheld a scene full of wild, tropic beauty. The white beach, blazingly radiant in the strong light, was bordered by a dense jungle of dark, melancholy looking mangroves. Beyond these came a tangle of brilliantly green jungle, in which the broad fronds of the banana plant predominated, while here and there a tall palm reared its feathery head.

Further back still the foliage changed again. Lordly groves of mahogany trees, rosewood, and giant royal palms raised their crests. In the distant background, far withdrawn, the misty blue outlines of a range of majestic, rugged-looking mountains showed against the steely blue sky. They looked as if they were hundreds of miles off at least; but Captain Andrews explained that the distance from the shore to the foothills was not so considerable, by a great deal, as it looked. The condition of the atmosphere, laden with the moisture of the lowlands, lent them this appearance of tremendous remoteness.

“It is in those mountains,” said Captain Andrews, “that the remnants of the most ancient of the Maya tribes still live. They tell stories up the coast, in the civilized portions of Yucatan, about vast ruins and remains of splendid cities to be found back there.”

The boys gazed up at him as he stood at the wheel. A magic world of romance and adventure seemed suddenly opened before them by his words.

“I recall reading once,” said Tom, the studious, “that the Mayas were civilized long before the Aztecs or Toltecs, and that their knowledge of the building arts exceeded that of either of those races.”

“Sort of pioneer real-estate men,” chuckled Ned Bangs, who in moments when he was not oppressed by trouble, as he had been recently, possessed a whimsical vein of humor.

“Ho! ho! ho! ah reckon dat’s right, Marse Ned,” roared Jupe, opening his big lips and exposing his ivories.

“Has any one ever penetrated into their country?” went on Tom, addressing Captain Andrews.

“I guess your father went as far as anybody,” was the response, “and you know how far he got. I have heard that the remnants of the ancient tribes have a law, making it death for the man who dares to advance into their territory.”

“But the natives that caught you didn’t seem disposed to kill you,” objected Jack.

“Oh, those fellows; they are of the inferior coast tribes,” was the rejoinder. “The ancient races regarded them as dirt under their feet. I guess they don’t know any more about the interior of those mountains than we do.”

The current of the river, discolored and yellow from the recent earthquake back in the foothills, was so swift as they ascended that Captain Andrews found no opportunity for further talk. It required all his attention to keep the Vagrant’s bow pointed upstream. The river narrowed considerably after passing its mouth. Its turbid current rolled seaward between two low and densely wooded banks, not more than sixty feet apart.

“How far is it to the spot where that craft of Herrera’s was moored?” asked Jack, when he found an opportunity.

“Fully fifteen or twenty miles, I should say,” was the response, “and if we are making two miles an hour against this current we are doing well. This river runs mighty near as fast as the Lachine Rapids back home.”

“You’re not far out on that, Cap,” remarked the volatile Ned Bang’s, who had quite recovered his usual flow of spirits.

The lad had not as much at stake as Jack and Tom, and, moreover, he did not quite realize the seriousness of the undertaking before them to the same extent that they did.

Hour after hour they fought their way up the coffee-colored river. The character of the vegetation on the banks had begun to change by this time. Here and there stood a majestic clump of mahogany trees; but logwood, a valuable article of commerce in the dyeing industry, formed the major part of the growth. Once, as they rounded a bend, the flash of a lithe body was seen among the trees, as a beautifully spotted jaguar slunk away from the overhanging limb where it had been lying.

“Let’s try the gas-guns on the next one we see,” suggested Tom, and the lads hastened below and returned armed with the odd weapons.

An opportunity to use them soon presented itself. From a thick mass of brake there came a mighty squealing and grunting, as the Vagrant came slowly around one of the numerous bends in the stream. All at once several small, bristly animals, like miniature pigs, dashed out with a mighty commotion.

Three gas-guns flashed to three shoulders simultaneously. It was an odd and rather uncanny sight to behold an instant later, six little wild piggies lying with their toes turned up, “dead to the world,” as the slangy Ned Bangs put it.

The boys were keen for going ashore and gathering in the victims of the ammonium nitrate compound. But Captain Andrews vetoed the proposal as impossible.

“There’s hardly a foot of water in shore there,” he said, “it’s a case of ‘keep in de middle ob de road’ in this river.”

Dinner was eaten at one o’clock. Jack “spelling” Captain Andrews at the wheel while the skipper partook of a hearty meal, after which he indulged in a nap while Tom, in his turn, relieved Jack.

The latter was still below enjoying Jupe’s cookery, when there came a sudden hail from above:

“Say, Jack, hurry up on deck, won’t you? There’s something odd about the water just ahead of us.”

Ned it was who uttered the summons, poking his head down the companion way.

Jack finished his meal in a jiffy, and was on deck in another two seconds. He found the Vagrant’s nose still pointed up stream, but Tom, using the bridge controls, had slowed down the engines till the craft was almost stationary in the swift current.

Right ahead of them lay the cause of Jack’s abrupt summons to the deck.

A chain, composed of huge iron links, was stretched from bank to bank of the river, effectually barring further progress.

“Well,” said Jack, after a moment spent in surveying the obstruction, “we might have expected something like that. The question is, what are we going to do?”

“We might land and remove it,” hazarded Ned.

But Jack shook his head.

“Jupe, go below and call Captain Andrews,” he said, in as calm a voice as he could muster. “We won’t risk landing and trying to lower the chain for two reasons. One is, that Herrera, having been cunning enough to put up the barrier, is not likely to have left it unguarded. There may be hidden eyes watching us right now. The second reason is, that it has just occurred to me that a man who is playing the game he is, may have placed other more dangerous obstacles in our path.”

“For instance?” came from Tom.

“For instance,—mines.”

“By the holy poker! That’s so,” exclaimed Ned, “I guess we’d better turn back and make our advance by land.”

“Here’s Captain Andrews now,” struck in Tom, as the skipper of the Sea King came on deck, hastily adjusting his white pith helmet.

There was no need to tell that veteran seaman what had happened. He took in the situation at a glance.

“It would have been funny if we hadn’t run up against something like this,” he remarked, almost in Jack’s words.

“The point is,—what now?” said Tom.

Captain Andrews agreed with Jack that it would be a foolish risk to land and try to remove the chain.

“I’ve quite a notion that there are some rifles in that brush, all ready for use in case we try to proceed,” he said reflectively, “my advice is to drop back down stream and hold a council of war.”

All agreed that this did seem about the only thing to do under the circumstances, and accordingly Tom handed the wheel over to the sailor while he went below to “stand by” the engines.

In that muddy stream, with its sand banks and shoals, the maneuver they were going to try would call for some delicate seamanship and swift handling of the motor.

Captain Andrews, with his lips grimly compressed, grasped the wheel and sounded a signal. Slowly the Vagrant, which had been “hanging” motionless, began to drop back with the current.

“Too bad we can’t turn around,” complained Jack.

“Wouldn’t dare to chance it,” rejoined the captain, “for all we know there may be a sandbank on either side of us right now.”

A deathlike silence hung over the Vagrant as she drifted stern first down the river. The wheel spun swiftly this way and that under the helmsman’s muscular direction.

“She goes as well backward as she does forward,” Ned was beginning, when there came a sudden shock that almost threw them off their feet. Jupe, in fact, did fall sprawling on the bridge.

At almost precisely the same instant a shower of bullets whizzed above them, singing a sinister song as they screeched about the motor craft. Dense brush lined the banks, and the shooters were well concealed in it. Not even a puff of smoke betrayed their exact whereabouts.

And, while this hailstorm of lead whistled about the adventurers, they realized all too clearly that the Vagrant had run hard and fast on one of the very sandbanks the captain had dreaded. One thing, however, speedily became evident, and that was that the bullets had not harmed them, because they were not intended to—yet. The shower of lead was aimed high above their heads. Presently it ceased altogether.

“That was a warning,” decided Captain Andrews. “Boys, your folks are certainly surrounded by a barb-wire fence.”

The lads did not answer. But as they sensed the nature of the obstacles that were piling up in the way of their enterprise, a look of consternation came over their faces. “The Chadwick Relief Expedition,” as they had christened it, appeared to have run up against a stone wall.

“I guess we are not in any danger of another fusillade if we stay where we are, or keep on dropping back,” said Captain Andrews after an interval of thought, “but if we try to keep on going we’ve had a sample of what to expect.”

The boys could not but agree with him. At length Jack spoke.

“Hadn’t we better try to get the Vagrant off whatever we’ve struck?” he said. “I’ve got a plan in my head in that case; but I don’t think this is the healthiest place to discuss it.”

“We can put out a light anchor and try to warp off,” said Captain Andrews.

It was agreed to try this plan for rescuing the Vagrant from her uncomfortable berth. The dinghy was lowered and manned by Jack and Tom, who took with them the light anchor which was attached to two hundred feet of line. A hundred feet down stream they dropped the mud-hook, and then rowed back to the Vagrant.

When they were once more on board the winch was manned and, to their delight, as the rope tightened the Vagrant’s stern began to swing.

“Keep at it, lads,” cried Captain Andrews to the perspiring laborers, “if that anchor will only hold I believe we can get off.”

The anchor did hold, and after ten minutes more of back-breaking work the craft’s bow slid out of the mud bank with a sucking sound, and she was once more free. The anchor was hauled on board, and, without further mishap, the Vagrant was set once more on her down-stream course.

The first attempt of the courageous little band to rescue their comrades had met with a rather ignominious failure. Captain Andrews said as much that evening, as they found themselves anchored near the mouth of the river they had fruitlessly ascended with so much pains.

The skipper voiced this opinion after supper, while they sat on deck casting anxious eyes to seaward now and again, for the recollection of the Tarantula was strong upon them. Above all things, they dreaded the reappearance of that drab-colored craft.

“You said you had a plan, Jack,” said Tom, as the skipper disconsolately drew on his pipe, “Now’s the time to broach it. What is it?”

“Just this,” was the simple reply, “we’ve got the aero-auto. It looks as if the time had come to use her.”

“And leave the Vagrant here to be destroyed when Herrera happens along?” demanded Tom.

“That doesn’t follow. Did you notice that small creek almost overgrown with brush that branches off about a mile above here?”

“Yes, lad,” came from Captain Andrews, whose tones gave evidence of his intense interest, “you’re planning to hide the Vagrant there till we come back again?”

“You’ve caught my idea exactly,” said the lad. “What do you think of it?”

“That it’s a dumb-gasted good one, and that I, for one, am willing to risk my neck in that flying automobubble of yours any time you say the word.”

“Then I say it right now,” shot out Jack, with flashing eyes. “We can’t ascend this river by water; we’ll try the air route.”

It was while they were still buzzing with the enthusiasm that Jack’s fiery words had created that Tom uttered a sharp exclamation.

“Jupiter!” he exclaimed, pointing seaward. “Look yonder. We’re not playing a lone hand in this thing now.”

Some distance off apparently, but rushing across the water at a swift pace, was a bright white gleam,—the light of a vessel approaching the bar at top speed.

“The Tarantula, for all I’m worth!” exploded Captain Andrews. “Confound her, why couldn’t she have kept her hands off for twelve hours longer?”

Fortunately, there was no ray of light visible about the Vagrant. The incandescents had been switched off in every part of her, with the exception of the engine room. In this compartment Tom, by some inspiration, had closed the deadlights, and therefore not a gleam of light leaked out to betray the whereabouts of the craft.

“Do you think the Tarantula will cross the bar to-night?” asked Jack presently.

“I don’t imagine so,” was the rejoinder. “They wouldn’t be idiots enough to take such a chance as that on this tide. No, if you ask me, we’ve got the night ahead of us till the first streak of daylight.”

“Good enough,” said Jack, with much inward satisfaction; “and now, I’ve been thinking, it wouldn’t be a bad idea for me to keep watch by the wireless. It’s likely enough that Herrera will try to send a message to his plantation up the river, provided he’s managed to get his apparatus repaired.”

“I’ve been thinking that, too,” said Tom. “I’ll go below and start up the generator.”

“You might as well,” said Jack, “although I don’t think that we’ll send out any messages to-night. Our job is to catch what we can from the air.”

While Tom hastened to the engine-room to start up the dynamo. Jack made his way to the cabin, accompanied by Ned Bangs. Captain Andrews and Jupe remained on watch on deck.

Seating himself at the wireless table. Jack adjusted the head band, placed the receivers at his ears, and then threw the switch for receiving. Ned, in the meantime, had run up the wireless mast with its slender antennæ, or aerials.

This done, Ned rejoined his chum, seating himself beside him. After an interval he spoke.

“Anything yet?”

“No; silent as the grave. Suppose you go on deck and see what Captain Andrews and Jupe have observed.”

Ned was back from his errand in a short space of time. His face bore a well-pleased grin, as Jack could see in the light of the solitary incandescent which illumined the cabin, the shades having, of course, been drawn across the portholes before it was switched on.

“Well?” questioned Jack.

“Well,” echoed Ned, “everything is going famously. The light stopped moving outside the bar, and presently Captain Andrews heard the rattle of her anchor chains as she let go her mud-hooks. Everything has been quiet since.”

“Too quiet. I wish——”

Jack broke off suddenly, holding up a hand to Ned to command silence. Out of space the electric waves were beginning to break against the aerials above. The Tarantula was talking to some one on shore in a rapid stream of dots and dashes. Jack’s hand flew across the recording pad. As before, the paper was soon covered with figures—the code which Tom had exploded.

After half an hour, during which his hand had frequently sought the tuning apparatus. Jack’s labors ceased; but his face bore a radiant expression.

“The message had a lot in it about us, and my father and the rest,” he said. “They did not codify our names, but spelled them right out. That’s how I know. They——”

“Hadn’t you better listen in case there’s any more coming?” asked Ned.

“No; they’re through for to-night. They exchanged the good-bye signal. Now to find Tom and get him to translate this jumble of figures.”

But Tom, after expending a lot of fruitless labor on the papers, declared he could make nothing of them.

“Maybe they’ve changed the code, or maybe——”

“They’ve been using Spanish this time,” exclaimed Jack, struck by a happy inspiration.

“Cracky! I’ll bet that’s just what they have been doing,” cried Ned. “Say, fellows, you just copy out those messages while I get Captain Andrews below in two shakes of a duck’s tail.”

He bounded off up the companion way, while Tom busily transcribed. So fast did he work that he had a lot of words written out when the skipper appeared.

“So you’ve been catching something out of the air, have you?” he asked as he entered the cabin.

“Yes; and I guess it’s important, too,” declared Jack, “but you’ll have to translate Tom’s notes. Captain, because it’s all in Spanish.”

“That will be simple enough,” said Captain Andrews, sitting down and drawing toward him the scattered sheets which Tom had already rendered from the figures of the code.

The veteran seaman began stolidly to con over the Spanish words, not all of which, owing to Tom’s unfamiliarity with the language, were written in correct form. But before long his composed attitude gave way to excitement.

“Jove, lads!” he exclaimed, “this wireless is a wonderful thing. It’s tipped off that greaser’s hand to us in great shape. He——”

“Wait till you get the whole message and then you can read it out to us,” suggested Jack.

Both the sailor and Tom worked like beavers at their task, and ere long Captain Andrews leaned back in his chair and announced that he was ready to read the messages as he had translated them.

As he had hinted, they caused a sensation. Herrera had wirelessed his plantation, and after a short interval had received a reply. He,—or, rather, his operator,—then proceeded to relate all that had occurred; and told,—the boys had to smile at this,—how the accursed gringos had tricked them by some sort of hypnotism!

However, so the message ran on, the capable Senor Herrera had managed to rally his men on their recovery from the spell of witchcraft, and had speedily organized a force to repair the damaged machinery and wireless apparatus. This done, all speed had been made at once for the coast whither, as they guessed, the gringos had preceded them.

“Well, Herrera’s, man ashore soon informed them on board the Tarantula that such was the case,” continued Captain Andrews, “and gave him a full, true and particular account of how they stopped us with that chain and that fusillade. He told Herrera that he had confined the gringos in one of the buildings used for the hemp crushers, and that they were as safe as if they were in a safe deposit vault. Friend Herrera then congratulated him on his astuteness, and said that he would run the bar first thing in the morning, only stopping, by the way, to blow the Vagrant out of the water and send us all to Kingdom Come.”

“Reckon he’s got another guess coming on that,” grinned Ned Bangs, looking at Jack.

“I hope so,” said that lad; “but now that we are in possession of these facts it’s up to us to move quickly. Captain, do you think we can find that branch creek in the night?”

“We’ve got to,” was the grim response, “if we don’t want to part with the good old Vagrant, and I’d hate to lose any ship I’ve trod the deck of.”

“Then, let’s up anchor and get out of here,” said Jack.

“Intercepting that wireless,” he went on, “has taken one great load off my mind. We know that those we are in search of are safe, and we know, in addition, that they are confined in one of the hemp-making buildings.”

“And that’s a whole lot important to us right now,” supplemented Captain Andrews. “Whole campaigns have been won with less knowledge of the enemy’s country than we have.”

They went on deck. Outside the bar a light showed where the Tarantula lay at anchor. Herrera must have been chuckling to himself at that very instant. According to his knowledge of the situation, he had his foes completely “bottled up.” All that remained for him to do was to capture them and attain possession; of the coveted precious stones at his leisure.

While the Mexican was pondering such thoughts as these and nursing his revenge, the company of the Vagrant were busy,—very busy.

It was too risky a thing to chance making the noise that raising the anchor would have caused. So the cable was slashed and the engine started with the underwater exhaust in operation. Noiselessly the little craft glided up the stream and then turned her nose toward the bank. A break in the line of trees, showing against the star-sprinkled sky, gave the location of the creek mouth, and, feeling his way with the utmost caution, Captain Andrews drove his temporary command into it. It was driving, in a literal sense, for the brush and trees overhung the creek so densely that the Vagrant had to push her way among them. When she had proceeded about a hundred yards up the stream she was masked from the view of the river with complete effectiveness.

“Glory be!” sighed Jupe, in a voice of intense relief, when Captain Andrews ordered the second anchor “let go.”

“It will be safe enough to light up now, I guess,” announced Captain Andrews, when the anchorage had been accomplished. Jack had told him previously that they would need deck lights to work by when it was possible to use them without danger of detection.

When the incandescents on the after deck were switched on the boys at once fell to work on their “Flying Road Racer,” as Jack and Tom had christened the craft. There was much to be done, and they worked quickly. The tank was supplied with crystals and water, and the gauge before long showed a pressure which the lads knew was sufficient to inflate the bag when occasion arose.

This done. Jack determined to make a test of the engines. First, seeing that the neutral clutch was in working order, he pressed a button which set the self-starting apparatus,—run by electricity from a storage battery of great power and lightness,—into action. With a buzz and a whirr the machinery started, and bit by bit the lad speeded the motor up to its maximum number of revolutions per minute,—namely, two thousand. While the crank shafts whirled round he carefully examined the lubricating appliances. They worked as well as everything else, and fully satisfied with his test, the young inventor shut down the engine, with the announcement that so far as the machinery was concerned everything was in readiness for an immediate flight, or ground cruise.

While this had been going on, Jupe had been placing a stock of provisions on board, and Captain Andrews had assembled his navigating instruments and chronometers, which he had brought with him from the Sea King. By midnight Jack declared that it was time for the aero-auto’s passengers to get aboard.

A thrill of excitement ran through the whole party at these words; but Tom seemed suddenly to recollect something and stepped to Jack’s side, talking in a low voice.

The young leader nodded his assent to Tom’s proposal, whatever it was, and Tom vanished below, summoning Jupe to help him. When he returned, he had his arms full of mechanical apparatus, and the same was true of Jupe, who grunted under his burdens. All this impedimenta was placed in the tonneau, in lockers under the seats.

It now only remained to bolt on the aerial propeller, adjust the side-planes and fix the rudder. This was speedily done.

At twelve-thirty o’clock the party cast off the lashings which had bound the Flying Road Racer to the Vagrant’s deck. Jack climbed into the driver’s seat, taking his place at the aerial steering wheel. Tom sat beside him.

Captain Andrews, Ned Bangs and Jupe, whose eyes were almost popping out of his head, seated themselves in the broad, roomy tonneau.

The lights had already been switched off on I board the Vagrant and everything made snug. The silver casket, the gas-guns, the ammunition, and the other accessories from the Professor’s cabin which had not yet been opened, were, of course, on board the Flying Road Racer.

Jack bent forward and snapped a button switch. A hooded light above the various gauges and instruments on the dashboard shone out, shedding a soft but bright light on the appliances, but not striking up into the young leader’s eyes.

“All ready?” queried the lad, giving a backward glance.

“Ready as we ever will be, old top,” quoth the slangy Mr. Bangs.

“Let her go,” said Tom in a tense voice.

Jack’s pulses throbbed, and his heart beat a bit quicker than was comfortable as he turned the valve that admitted gas to the bag above them.

With a swishing sound, not unlike escaping steam, the folds of the great gas container began to fill out. It gradually assumed shape, swelling till it reached what appeared to be vast proportions. When Jack shut off the gas the huge, cigar-shaped balloon above them looked like an immense dark cloud, superimposed over their heads.

The bag took just fifteen minutes to inflate. During this time not a word was spoken on board the Flying Road Racer. The tension was far too great for speech.

As Jack shut off the gas a tremor ran all through the novel craft. She tugged and swayed at the single rope, reeved through a ringbolt, that still bound her to the deck. The suspension wires thrummed musically under the pressure.

“Let go!” yelled Jack suddenly.

Tom, who had been holding the end of the rope, dropped it. Instantly the Flying Road Racer gave a bound upward.

“Bust my toplights!” bellowed Captain Andrews in excitement at the novel sensation.

Jupe’s lips might have been seen to move. He appeared to be praying. Ned Bangs’ hands were clenched tightly. He was very pale.

“Look out for the tree tops!” cried Tom suddenly.

The wonderful craft, with her precious freight, swayed drunkenly toward the crests of a group of giant ceiba trees. For one instant disaster, at the very outset of their voyage, appeared inevitable.

But suddenly there was a whirring sound, like the drone of a monstrous night beetle. The engine was driving the propeller round at top speed.

Jack twisted the steering wheel over, and the Flying Road Racer, rising at the rate of a hundred feet a minute, shot clear of the menacing tree tops.

Up and up into the night she rose, while her occupants, forgetting their first alarm in their enthusiasm, gave a mighty cheer, careless, for the minute, of who might hear it.

The voyage of the Flying Road Racer had begun under a fortunate star indeed.

Directly the tree tops were cleared Jack set the planes at a rising angle, and the upward course of the Flying Road Racer was more rapid. She seemed fairly to shoot up into the ether.

“How do you like it?” asked Tom, turning his head-to speak to those in the tonneau.

“Ah’d like it better, Marse Tom, ef I didn’t feel I done lef’ mah insides behin’ me,” faltered Jupe.

“You’ll soon get over that feeling,” declared Tom confidently. “Just hark at that engine! She’s running as true as a human heart.”

“She is that,” agreed Jack, enthusiastically, “Tom, old boy, we’ve got the greatest land-and-air-craft ever put together.”

“And to think that you two lads, hardly more than schoolboys, invented her,” struck in Captain Andrews admiringly.

“I guess my father had a whole lot to do with it,” rejoined Jack modestly; “we could never have mastered a lot of knotty points without his aid.”

“Well, that doesn’t detract from what you’ve accomplished one bit,” declared Ned with enthusiasm. “This is the mode of traveling of the future all right.”

“We hope to make it so some day,” was Tom’s reply.

The night was almost windless, save for a slight puff now and then. But this didn’t bother the Flying Road Racer once she was under control, and Jack had managed to climb upward on an almost straight course.

Now he peered over the edge of the aluminum body. Beneath him he could see the gleam of the river in the starlight.

“We’ll follow the stream,” he decided. “It is bound to bring us to Herrera’s plantation.”

“Keep at a good height, though,” admonished Captain Andrews. “We know that those fellows have high-powered rifles.”

“We are now twenty-five hundred feet above the earth,” said Jack, glancing at the barograph. “We’ll go higher.”

He pulled a lever, setting the rising planes at a more acute angle. Up the aerial staircase they climbed, till the barograph’s indicator pointed to the figures five thousand.

Then Jack turned the prow of the craft in a westerly direction, while Tom, through night glasses, watched the earth so far below them, following the course of the river through the binoculars.

At forty miles an hour the Flying Road Racer swept through the air on her momentous errand.

When the Flying Road Racer took the air the weight that the craft carried was distributed as follows:

Aluminum body, wheels, motor, suspension wires, etc. 900 pounds.

Five passengers. (approx.) 800 pounds.

Provisions, water, etc. 250 pounds.

(The provisions included canned goods, preserved butter, tea and cocoa, flour, sugar, salt and a few delicacies.)

Radolite crystals, instruments, etc. 275 pounds.

Other articles,—including Ned’s last-minute contributions. 300 pounds.

Total 2,525 pounds.

This left lifting power to raise 2,475 lbs., which, however, could be increased to a considerable extent by utilizing the reserve sections of the gas bag.

Jack roughly estimated the combined weights of those they were to rescue,—his father, his uncle, Abner Jennings and the two sailors,—at a little over one thousand pounds. Thus, it will be seen, that there was no reason why the Flying Road Racer should not be able to perform all that was required of her, with some lifting power left over for emergencies.

The boy inventors’ craft had been in the air about an hour when Tom descried, far below them, the gleam of a light. In that wild country it was not likely to betoken anything else but the site of Herrera’s plantation houses.

They all agreed on this, and Jack, after a consultation with his comrades, decided that the time had come to descend. The plan they arrived at, after threshing the situation over in all its bearings, was to drop in the most suitable place they could find, adjacent to the plantation buildings.

Then the gas bag was to be reinflated, ready for emergencies, and two of the party were to reconnoiter the ground as carefully as possible. The remainder of the rescue was to be left to circumstances. At one hour and ten minutes after midnight. Jack started the exhaust engine up.

Instantly the Flying Road Racer began to drop downward through space with her planes set at a slight angle, as Jack did not want to coast to earth too rapidly. This course soon brought the craft above the summits of the forest trees, at a safe distance from the light they had perceived from aloft. To make assurance of being unnoticed doubly sure. Jack had shut off the motor. Silently as a night bird the great bulk of the flying auto settled earthward.

All this time their eyes had been strained to sight an open space in which they might land without risk of damaging the balloon bag. Tom was the first to see, through the night glasses, such an area of cleared land amid the forest.

It was a tract about ten acres in extent, and formed, as they surmised later, one of the outlying fields of Herrera’s plantation. It had not yet been put into cultivation, however, and afforded as fine a spot for an air craft to ground as could be imagined. Half an hour after the descent had begun the Flying Road Racer settled as lightly as a bit of breeze-blown down on earth once more.

Thanks to her shock absorbers, hardly a jar was felt by those on board as she landed with her bag half deflated and limp and wrinkled. No time was lost in alighting and throwing out the anchors, contrived by Jack, used for securing the craft to earth in case of a sudden wind springing up. These anchors differed considerably from the sea type of “mud hook.” They consisted, in fact, merely of discs of iron shaped like an inverted mushroom. One edge of the disc was driven into the ground, and the shape of the holding appliances was such that an upward tug merely served to force them more deeply into the earth.

The adventurers figured that they were about half a mile to the west of the spot where they had seen the light, which they believed marked the site of Herrera’s plantation houses. They also estimated that there were left to them about two hours and a half more of darkness. There was urgent necessity then for immediate action.

Much to the chagrin of Tom and Ned, but to the huge delight of Jupe, who had no great fancy for the work in hand. Jack and Captain Andrews were to be the ones to do the reconnoitering. Tom and Ned were ordered to stand by the Flying Road Racer and be ready for any sudden development that might occur.

While Captain Andrews and Jack were absent, it would be the others’ duty also to refill the gas bag, so that the aero-auto might be ready for an instant ascent in case of need.

These preparations completed, the two who were to assume the most risky part of the night’s work each selected a fully loaded gas-gun. In addition. Captain Andrews carried an automatic revolver; but it was on the former weapons that they would largely depend.

There remained nothing more but the leave-takings, and the fervent wishes for success in the daring enterprise, coming from the lads who were to be left behind. These final ceremonies being disposed of, the grizzled old sailor and his young companion set off. Tom and Ned watched them till the shadows of the forest swallowed them up.

By good fortune, the two, upon whom so much depended, struck a trail almost immediately after their first plunge into the blackness that prevailed under the tropical trees. The path had evidently been used by the laborers who had made the clearing beyond. It was a broad, well-defined track, and their progress was rapid and almost noiseless.

Neither of them spoke as they made their way along the path. The situation was too critical for words, and Jack crept along behind Captain Andrews, hardly daring to breathe.

He was on the tip-toe of excitement and anxiety, as was natural. At the end of the trail they were following’ lay either success or dire failure. There was no middle ground. In the event of their failing in their mission. Jack could not disguise from himself that the consequences would be awful indeed. He had come in contact with Herrera only once, but that single occasion had amply sufficed to show him the character of the man.

From time to time, as they advanced, they paused and listened intently. But, except for the drone of the night insects of the jungle, and the occasional scream of a nocturnal bird, there was no sound other than the sighing of the breeze in the tree tops far above.

There is no place more mysterious than the jungle at night. The dense thickets seem to the nervous traveler to hold all manner of hidden perils. Some of these are not altogether imaginary, either. The cunning, cruel jaguar, the huge serpents, and a score of other dangers lurk in the shadows.

Fortunately, neither of our friends was burdened with sensitive nerves, and it was well they were not, for their errand was not one for timid folk to embark upon.

They glided along after all these pauses, making as fast time as possible. All at once Captain Andrews, who was in the lead, as we know, stopped abruptly.

So abruptly, in fact, that Jack almost collided with him.

“What’s the——” began Jack.

But instantly the Captain clapped a hand over his mouth. He raised the other in a gesture that Jack read instantly: “Silence!”

Just ahead of them. Jack now perceived, the path broadened and emerged on a considerable clearing. The black outlines of several buildings, were scattered about this open space.

From one of them hung a lantern, shedding a yellow patch of light all about it. This, evidently, was the light they had seen from above.

As they stood, still as graven images in the protecting shadows of the forest, a stalwart figure, with a rifle over its shoulder, paced into the circle of light and then vanished again.

“A sentry!” huskily breathed Captain Andrews. “If we thought we’d catch them napping we’ve been badly mistaken.”

Jack gave a step forward the better to survey the scene before them. As he did so his right foot struck something, and the next instant there was a sudden sharp jangling of a bell.

In a flash he realized what had happened. A wire connected with the bell had been stretched across the path,—Herrera’s dead line. His forward step had given the alarm, and might prove their undoing and cause the total failure of their plans. Captain Andrews’ arm shot out and dragged the boy back into a clump of brush. He made Jack lie down flat, doing so himself.

“The whole pack will be about our ears in a minute,” he whispered; but he did not reproach Jack, whose face was burning with humiliation.

Sure enough, almost simultaneously there came from the direction of the houses and sheds an excited clamor of voices. Lights flashed and figures could be seen rushing about. Presently they gathered in a knot, and some one appeared to be giving directions; then they scattered in a fan-shaped formation, and moved toward the woods in which the two adventurers lay concealed.

Jack’s heart beat like a trip hammer. Beside him he could hear Captain Andrews breathing heavily. Their discovery, within the next few minutes, appeared inevitable. Flashing their lanterns hither and thither the searching party, which they could now see was composed of negroes, from the Mosquito coast in all probability, advanced toward the jungle.

There were a dozen or more of them, headed by the big fellow whom they had noticed on sentry duty. Almost all of them carried the universal weapon of the negro in the tropics, long, glittering-bladed machetes. Some of them took to the path by which Captain Andrews and Jack had reached their present position. Others plunged into the jungle, cutting away the thick growth with their steel blades.

Their leader shouted something in Spanish. “He’s ordering them to search every inch of the jungle hereabouts,” interpreted Captain Andrews in a whisper. “The precious rascal! I’d like to have my hands on him.”

“It wouldn’t do much good,” was the mournful response; “the odds against us are too heavy for us to do much in case of our discovery.”

“Well, we’ve got the gas-guns, and from what I’ve already seen of them I reckon that they may prove mighty useful in a few minutes.”

As he spoke there came a crashing sound in the undergrowth a few feet from them. The next moment they saw the form of a giant black looming up directly in front of them. The fellow was grunting from his exertions in cutting his way through the underwood, and paused for an instant to catch his breath.

It was a fatal pause for him. Jack gently drew his gas-gun toward him and fired. The negro threw both his hands into the air and dropped with a loud “Oof!”

But the shot had been at such close range that the powerful gas impregnated the air that Captain Andrews and his young companion were breathing. The reek of it stung their nostrils.

“We’ve got to get out of here,” whispered Jack, “or we’ll be as dead to the world as that fellow is.”

Painfully they crept on their stomachs through the thick brush, moving as silently as cats. A single mistake in their movements, the crack of a branch snapped by carelessness might, as they both knew, prove fatal. But they managed to gain a small clearing under some big trees without mishap.

It was at this moment that Jack had a sudden inspiration.

“See here,” he said excitedly, under his breath, “those chaps have worked past us now, to judge by the sounds. They think that we have fled through the woods. What’s the matter with our doubling back on our tracks and marching right into the settlement?”

Captain Andrews, ungiven as he was to emotion, fairly gasped.

“By the beard of Neptune, boy!” he exclaimed, and then, in the same breath, “but it’s not as mad a plan as it sounds. In all likelihood, almost the entire force of guards from the plantation buildings are out after us, and we ought to be more than a match for half a dozen with the gas-guns.”

“Then we’ll do it?” throbbed Jack, with a catch of his breath.

“Yes. We came here to rescue those poor chaps, and, by the Polar Star, we’ll do it if it’s possible.”

Jack impulsively held out his hand. Captain Andrews clasped it warmly. The next moment they were stealthily creeping through the undergrowth, but advancing far more quickly than they had retreated a moment before.

When they once more gained the edge of the jungle. Jack perceived, to his intense satisfaction, that everything was quiet about the handful of buildings before them. So far as could be seen, there was no one about. Evidently then, his surmise had been correct. The majority, if not all of the residents, were abroad in search of the persons who had sounded the alarm bell.

“Which building do you think it likely they are in?” asked Jack, as they paused an instant before plunging from the protection of the woods.

“The one that has that lantern hanging on it,

“I imagine,” was the response from the veteran seaman, “we’ll try that first, anyway. Are you ready?”

Jack nodded. He did not speak, however. It was not a time for mere words. The next moment they had passed from the dark shadows of the jungle into the open space about the plantation buildings. Each clasped his gas-gun ready for instant use. But nobody appeared to bar their progress.

When they gained the structure from which the lamp was hanging, they found that it was a tall building of wood, and seemingly three stories in height.

It was used, though they did not know this at the time, as a drying house for the hemp after it had been through the crushing and separating processes. The door was secured on the outside by a weighty bar of wood. Captain Andrews lifted this out of its sockets, and in a jiffy had flung the door open. Inside was pitchy darkness, so black that it could almost be felt.

Jack had brought along his electric pocket lamp. He drew it out and switched on the current. The rays revealed a large, bare chamber, empty, except for a pile of dry hemp in one corner, and in another a few bales of the product stacked ready for shipment.

“Nothing here,” said Captain Andrews briefly.

“No; but see, there’s a flight of steps in that corner. Let’s go higher and find out what’s on the floor above.”

“It may be wasting precious time, lad.”

“On the other hand, this was the building that was guarded by the sentry. It’s fair to assume, then, that it is in this structure that our friends are confined.”

Captain Andrews had nothing to reply to this logic, and followed Jack up the steps.

At the summit of the rickety staircase was another door, secured, as had been the one below, by a stout bar of wood. Jack tackled this and wrenched it free. As he did so a voice that thrilled him in every fiber came from within the portal.

“Who is it?”

“Dad! It’s me—Jack—I’ve come to save you!” blurted out Jack, tears of sheer gladness springing to his eyes. He flung the door open.

The next instant Jack was clasped in his father’s arms, while about him and Captain Andrews, pressed the other captives, all well and unharmed and half wild with delight as they greeted the lad whose pluck had conquered Herrera’s “deadline.”

Naturally, after the first greeting’s had been exchanged, Mr. Jesson’s principal anxiety was for his son Tom. Jack soon set his mind at rest on this subject.

“Tom and Ned Bangs are back on the other side of the woods, with the aero-auto,” he explained.

“Ah, then it has proved a success?” eagerly interjected Mr. Chadwick.

“It is even better than we hoped it would be,” rejoined Jack enthusiastically.

“I wouldn’t be scared to trust myself to that aerial wind-jammer for a voyage to China,” stoutly declared Captain Andrews. “I reckon if Wellman had had a craft like that he’d have crossed the Atlantic easy as shooting.”

“I don’t know but what you’re right,” said Jack; “but the thing to discuss now is how to get out of here. Dad, do you know much about this place?”

“Nothing, except that there is a floor above this. We were confined there the first day of our captivity. But the sheet iron roof used for drying hemp made it so insufferably hot that we would have died if they hadn’t moved us down here,” was the reply.

“Then, so far as you know, there is no way of getting out but by the door we entered?”

“That’s the only way, I guess. We had better make good our escape while those rascally hangers-on about the settlement are off hunting for the fellows who rang their alarm bell.”

Professor Chadwick, to whom Jack had given a hasty outline of the events of the night, moved toward the door as he spoke. But he had not taken more than two steps toward the head of the stairs when he stopped abruptly.

“Hark!” he exclaimed, standing stock still in an attitude of close attention.

The murmur of voices came toward the party. It didn’t take any of them long to surmise what had happened. The searching party was coming back. In a few moments their egress would be cut off and it would be impossible to escape without a fight, the outcome of which was doubtful.

In this emergency Captain Andrews acted quickly. Gas-gun in hand, he ran down the stairway, shouting to the others to “come on.”

They pressed close behind him, each with a grim determination to reach the doorway before the guardians of the plantation noticed that it was open.

But in this they were disappointed. Hardly had Captain Andrews reached the doorway before several forms blocked it. As the doughty sea captain sprang at the foremost of them, at least a dozen of the husky henchmen of Herrera leaped on him.

Before either he or Jack could use their gas-guns, Captain Andrews was borne to the ground, while on top of him were piled half a dozen of the returned search party.

“Back to the upper room,” ordered Jack, “I’m going to fire my gas-gun.”

The boy shouted this warning because he knew that in that narrow space the fumes of the stupefying gas were likely to prove as disastrous to the white men as to the brawny negroes. Professor Chadwick, who well knew the qualities of the gas, retreated with the others. As he did so. Jack saw a rifle aimed at him by one of the negroes who crowded the doorway.

In a moment he had the gas-gun at his shoulder. He pressed the trigger and one of the sleep-laden globules shot out. It struck the armed negro in the chest, and the fellow threw up his arms with a sharp exhalation of his breath. Then he fell, as if his legs had been pulled from under him.

The fellows who were piled on top of Captain Andrews released him and dashed toward their other foe. As they left him the skipper of the Sea King sprang to his feet and discharged his weapon. The air became impregnated with stifling fumes.

Through the reek the seaman struggled to Jack’s side, and before the dazed negroes could realize what had occurred the two whites were shoulder to shoulder on the stairway.

Almost simultaneously the contents of the gas spheres began to have their effect. Man after man of those who remained, for several had fled, staggered and fell, while Jack and the captain retreated up the stairway. They lost no time in reaching the door at the head of the stairs and shutting it to keep out the fumes. They were none too soon. The gas had already affected them, and their heads throbbed and their eyelids felt leaden.

In the corner of the room was a big earthen pitcher of water. The Professor threw the contents of this over his son and Captain Andrews, and though still heavy from the effects of the gas, the shock revived them wonderfully.

“What now?” asked the Professor, after Jack and Captain Andrews had “come back to life” a little.

“Wait till the fumes of the gas have evaporated through the open door downstairs, and then make a dash for freedom,” said Captain Andrews.

“How long will it be before the air is good to breathe?” inquired Mr. Jesson.

“About fifteen minutes,” said the Professor; “the gas is of a very volatile nature, and the fumes will soon clear off. It will be an hour or so at least, however, before the negroes recover.”

“I would suggest, then, that Jack gives us a more detailed account of what occurred after he left Lone Island,” said Mr. Jesson.

Falling in with this idea, they seated themselves about the lad, who at once plunged into the details of the narrative, which, as may be imagined, proved of engrossing interest to all who heard him.

He was interrupted several times by questions and requests for information concerning the operation of the aero-auto, and the relation of his story took longer than had been anticipated. However, even in their critical situation, no one wanted to miss a word of it.

“And so the three gems are safe?” said Professor Chadwick, with a sigh of relief, as the lad concluded.

“Yes. They are at this moment in the Flying Road Racer’s locker, in charge of Tom and Ned,” was the reply.

As Jack spoke they all, by mutual consent, rose and made for the door.

“I shall be glad to get to the air,” remarked Professor Chadwick.

“Yes; it is insufferably hot in here,” agreed Mr. Jesson. “I had not noticed the heat so much while Jack was talking; but now,—phew! It’s like a furnace.”

As he spoke. Jack flung the door open. The next instant he staggered back, the hot blood in his veins frozen with horror.

A rush of air, hot and arid as a blast from a coke oven, struck him in the face. A great puff of smoke followed.

The room below was a vast furnace of red flame. In falling, one of the negro’s lanterns had overturned and rolled against the bales of dried hemp. All the time they had been talking the fire had been waxing more and more furious.

By this time the lower part of the stairway was in flames, and, as Jack held the door open, a tongue of fire, sucked upward by the draft, shot hungrily toward him.

He slammed the door instantly. But the heat of the seething furnace below rendered the air almost unbreathable.

It looked as if, in the very moment of their triumph, the adventurers were doomed to death in the burning building. Trapped and helpless, for an instant they were deprived of words. Was this to be their appalling destiny, their fate,—to be roasted alive without a chance of escape?

There are some situations so overwhelming that the strongest and coolest may well be temporarily stunned by them. The springs of action paralyze, while the mind becomes a blank.

This was the case with our party of adventurers. Added to this, was the horror of knowing that many of the negroes in the room below must have perished in the flames. Jack felt a sickening feeling of panic clutching at his heart.

In one corner of the room the two sailors crouched, stolidly awaiting death. Professor Chadwick and Mr. Jesson alone remained calm. Even Captain Andrews and Abner Jennings appeared dazed and helpless with the sickening sense of the disaster that had overtaken them.

“We must leave this room at once.”

It was Professor Chadwick who spoke, in a voice that did not falter in its resolute tones.

His calmness, in the face of death, restored Jack’s pluck and heartened Captain Andrews and Abner Jennings. Even the two sailors appeared to be less panic-stricken.

“We can only leave it for the room above,” objected one of them, however; “the flames will reach there afore long. Might as well die now as an hour later.”

“Shame on you for American seamen!” burst out Captain Andrews, “rouse up there! While there’s life there’s hope.”

His words were effective. At any rate, no more grumbling was heard as the beleaguered party ascended to the upper chamber. Like the one below it, the place was bare, and Jack flashed his electric searchlight about without discovering any loophole of escape. As was the case in the lower chamber, the walls were unpierced by windows, and the timbers were too solid for it to be feasible to knock them out, except with heavy sledges.

All at once, however, Jack noticed, as he flashed his light about, that in one corner there seemed to be a sort of trap-door in the roof.

He hailed his discovery with a cry of delight. If they could only reach the roof it might be possible for them to attract the attention of some one below who could get a ladder.

Of course, in that event, they would be likely to be made captives, but anything was preferable to a tomb in the flames.

Jack’s discovery acted like a tonic on the despairing feelings of the party. The iron roof was two feet beyond the reach of the tallest of them, but this difficulty was gotten over by Jack clambering to Captain Andrews’ shoulders, and from that situation he was able to reach the trap-door and to open it, for his first fear that it might be locked proved to be without foundation.

Having opened it. Jack clambered through, and lying flat on the roof extended his hands to his father, who, in turn, used Captain Andrews as a ladder. Then came Mr. Jesson, followed by the two sailors. Abner Jennings demurred to taking precedence of the Captain. But,——

“The skipper’s the last to leave the ship, my lad,” declared Captain Andrews, and Jennings, unwillingly enough, clambered on his back and was drawn up.

Then came the Captain’s turn. Abner Jennings, as the strongest of the party, lay flat on his stomach and extended his arms down within the room. To his legs clung the others, acting as anchors. With a mighty heave Captain Andrews, no lightweight, was raised high enough for him to clutch the edge of the trap, after which he completed the operation of getting through for himself.

As he gained the roof they heard a crash beneath them.

“The floor of your jail has fallen through, I reckon. Professor,” grimly spoke the captain.

As Jack heard the angry roar and crackle of the flames beneath them he could not repress a shudder. It was a drop of fifty feet or more to the ground, and they were by no means out of danger.

“Let’s see if any of those black rascals are about,” said Captain Andrews, “if they are we may be able to induce them to get a ladder.”

“Surely they wouldn’t be inhuman enough to let us remain here,” exclaimed the Professor.

“I don’t know,” was the response, “like master, like man, you know; and this might strike Herrera as a very neat way of disposing of us.”

Several forms could be seen flitting about below them. The flames were pouring through the windows of the lower story of the hemp-drying building, casting a ruddy glow in which near-by objects could be seen as plainly as if by daylight.

But the negroes appeared to be giving no thought to the burning structure. Instead, they could be seen dragging piled bales of hemp out of danger of flying sparks. Nor did they pay the slightest attention to the frantic shouts of the party marooned on the top of the blazing building.

“Great heavens! they mean to leave us here to roast to death,” groaned the Professor.

As he spoke there came another crash below them, and the building trembled.

“The floor of the second room has fallen!” cried Mr. Jesson, rightly guessing the cause of the crash. “In a few seconds this roof will become red-hot, and——”

He stopped short. There are some things that cannot be put into words.

The trap-door had been closed, but before long they could distinctly feel the roof under their feet becoming warmer and warmer.

Suddenly Jack espied a great mass of green hemp piled off in one corner, ready to be raked out on the iron roof for drying when the sun arose.

“We can put that under our feet,” he said, “and stick it out a while longer that way.”

So tenacious is the instinct of clinging to life, that even though they knew it would only avert the end by a very short time,—unless a miracle came to aid them,—they adopted Jack’s idea.

But before long the hemp began to smoke and steam. The heat was rapidly drying out the moisture, and then——

Suddenly one of the sailors gave a yell, and shouting,—“I’m going to end it all right now,” made a plunge for the edge of the roof.

His evident intention was to hurl himself down to death.

But before the crazed man could carry out his plan Captain Andrews sprang at the fellow and brought him down with a crash.

“If Providence means us to die, we’ll meet death like men,” he said stoutly; “but it’s not like Americans to give up the ship while there’s a shred of hope.”

The frenzied sailor fought and struggled on the pile of steaming hemp on which the skipper held him. But Captain Andrews’ strong arms pinned him down.

Jack felt his senses reeling. The hot breath of the fire had reached them by this time. The roof gave off heat like the top of a stove. If it had not been for the damp, green hemp they could not have held the situation for an eighth of the space of time that they did.

Their throats grew parched and their tongues swelled till they were painful, and they could shout for aid no longer. For all the attention the negroes below paid to their cries, they might as well have remained silent. The blacks seemed to consider the removal of the hemp to a safe place of far more importance than the lives of the flame-marooned white men.

Just when Jack’s hope had flickered out and a sort of coma of despair was creeping over him the miracle happened.

It was Professor Chadwick who saw it first.

Through the red glow that crimsoned the sky came a huge floating form.

The Professor shouted and pointed upward. Jack raised a pair of dimmed eyes; but the next instant they cleared as if by magic.

“It’s the Flying Road Racer!” he shouted, yelling like a madman. “Hurray! We’re saved! we’re saved!”

And then something in his head seemed to snap with a loud report. He swayed, and would have fallen heavily on the hot roof if his father had not caught him in his arms.

Then he was startled into alertness again by a sharp hail which came from above them.

“Stand by for a rope. We’ll drop as low as we dare!”

Just what happened in the moments that followed neither Jack nor any of his companions has ever been able to describe in detail. It was a time in which every second counted, while under their feet the flames roared and crackled hungrily.

From the Flying Road Racer a rope came snaking down, and Professor Chadwick caught it. At the corner of the roof in which the adventurers were huddled was a stout post, used sometimes, apparently, for hoisting things from the ground, for a pulley hung from it.

With a flash of inspiration the Professor, with Mr. Jesson and Jack aiding, rove the rope through this pulley. Then, while Tom and Ned maneuvered the Flying Road Racer so that her “bow” pointed downward, all of the marooned adventurers who were able to do so heaved on the rope. In this way the air craft was brought to within three feet of the roof.

Another length of rope was then looped over the side by Tom and made fast to two of the stanchions of the balloon support. The first to test the loop was the companion of the crazed sailor. Half dragged, he scrambled into the body of the suspended car. Professor Chadwick followed, and then came Mr. Jesson, while a delighted cry at his father’s safety came from Tom.

Abner Jennings was the next to be taken on board, and then came Jack. In the meantime Captain Andrews had buckled his belt around the limbs of the crazed sailor and had borrowed Jack’s for the purpose of confining his prisoner’s arms.

Trussed up in this manner the poor fellow was handed up to those on the Flying Road Racer, and then the gallant Captain Andrews made a spring for the swaying loop.

He was in the nick of time. As he gained the tonneau and sank to the floor almost exhausted, there was a deafening roar, and, as if it had suddenly melted away, the entire building collapsed. Jack turned away shuddering as the flame and sparks shot up above the ruins.

The ideas it suggested of the fate that might have been theirs if help had not arrived in the very nick of time, were almost overwhelming.

Tom was at the helm, and Ned it was who had cast off the rope. Slowly, almost Phoenix-like, from amidst the flames rose the Flying Road Racer with her heavy burden.

There was danger in the situation, too. The gas in the bag was inflammable, and the heat of the fire might expand it so that at any minute it might burst the container, and cause an appalling catastrophe. This danger Tom and Ned had willingly faced when they brought the Flying Road Racer to the rescue. But now, all their desires were centered on getting as far away from the fire zone as was possible.

Laden as she was, the great air craft had not the same buoyancy that had been hers when she set out at midnight from the Vagrant. She rose slowly, and although her propeller was whirring at top speed, and her rising planes were set, she once or twice sagged dangerously.

While this behavior on the air craft’s part was worrying her navigators seriously, there came a sudden fresh cause for disquiet. Bullets from the negroes below began to whiz about them.

The fellows had luckily been too much astonished to fire while the task of rescue was going on. The apparition of the sky-ship had taken them so much by surprise that they had temporarily been unable to take any hostile action.

Now, however, they had recovered their senses and were doing all in their power to render the escape of their late prisoners an impossibility. Luckily, however, they did not have enough sense to fire at the balloon bag, or their endeavors might have been crowned with success. Instead, they aimed at the occupants of the suspended car, and what with bad marksmanship and excitement failed to hit any of them. True, a few bullets pinged against the suspension wires and struck the sides of the car; but none punctured the tank, as the boys feared might be the case, or caused any serious injury.

A breeze springing up presently wafted the overladen airship into an upper air current, and before long she was rising merrily. More gas had been turned into the bag, increasing its buoyancy, and by the time the dawn began to show grayly the adventurers were far from the scene of their fearfully narrow escape.

Behind them, however, they could see, as the light grew stronger, a pillar of dark smoke soaring heavenward and marking the site of what had almost proved their funeral pyre.

What with the coming of daylight and the feeling that they had been saved from their greatest peril, the adventurers’ spirits rose wonderfully as they sailed along. Even the crazed sailor showed symptoms of returning sanity, and, as Professor Chadwick expected, his mental disengagement soon passed away. Oddly enough, though, he could never recall the events of that night. They had been wiped from his recollection as an old sum is washed off a slate.

Jupe got out canned goods and made a fairly good breakfast, while they were in mid-air. To some of the party it was the most novel meal they had ever eaten. But neither their recent hardships nor unusual surroundings impaired their appetites. All ate ravenously and felt much better after the meal, which included hot coffee cooked on an electric radiator. This radiator was connected with the dynamo that filled the storage batteries and provided engine ignition and light.

During the meal, Tom told them how he and Ned and Jupe had waited beside the Flying Road Racer after the departure of Tom and Captain Andrews on their scouting expedition. For some time they stood their ground patiently enough, and occupied their time, according to instructions, by reinflating the bag.

This done, there was nothing to do but await the progress of events. Of the search in the jungle they knew nothing. But the sound of shots from the direction of the plantation had first roused their fears that something was wrong.

Then they had perceived the red glare of the fire on the night sky. Certain then that something serious was wrong, Tom took it upon himself to get up the anchors and fly to the rescue. Little did he imagine, however, he confessed, what dire straits his friends were in.

“We owe you a great debt of gratitude, you and Ned Bangs, for your prompt and brave action,” warmly declared Professor Chadwick.

That the others heartily seconded the motion may be imagined. In fact, as they all realized to the full, they owed their lives directly to Tom Jesson’s pluck and brains and his able assistant, Ned Bangs. Jupe, too, came in for his share of praise, for the old colored man had behaved in the great emergency through which they had passed, with remarkable coolness and ability.

As Tom concluded his story. Jack glanced at the barograph. They had risen to three thousand feet, and were moving in a westerly direction. So engrossed had they all been in discussing their wonderful escape, that they had really hardly noticed in what course they were sailing.

“I think it’s time that we decided on a destination,” said Jack, as he noted these things.

“Why not try for Lone Island?” said Mr. Jesson. “The Sea King should be there, and——”

Jack shook his head.

“The Flying Road Racer couldn’t fly as far as that?” asked Captain Andrews, who had been glancing about him at all points of the compass while this talk was going on.

“She could fly as far as that under normal conditions,” was the reply; “but not with such a load on board. We are using up fuel at twice the usual rate, and might have to descend to make more gas for running purposes.”

“Can’t we refill the reservoir in mid-air?”

Mr. Jesson asked the question.

“Too dangerous, except in case of absolute necessity,” said Jack; “it could be done, but there is a certain amount of risk.”

“I think, then, that we had better head about and make for the sea-coast where the Vagrant is hidden,” said Professor Chadwick.

“I don’t agree with you there,” said Captain Andrews positively.

“Why not?”

“Well, in the first place, during the next few days Herrera is going to go through all that vicinity with a fine-tooth comb. He won’t let the gems slip through his fingers without some sort of a battle for them, you can bet.”

“What would your advice be, then?”

“To make for the mountains yonder with all speed. We can lie snugly hidden there for a short time, and can form some definite plan. We are all too much tired and overwrought now to discuss such things intelligently.”

“I think you are right. I know that, now that the strain is over, I feel like taking a long sleep,” said Mr. Jesson.

“Then let us head right on as we are going,” suggested Jack. “That range of hills doesn’t look so very far off. We ought to get there before afternoon. That will give us time to make camp and get things snug for the night.”

And so it was arranged. But Captain Andrews still kept casting anxious glances back toward the coast line.

“What’s the trouble. Captain?” asked Jack presently, noting a trace of uneasiness on the old sailor’s countenance.

“Why, lad, I don’t much like the look of the weather yonder. See that gray haze that’s spreading over the sky so quick? That means wind, and maybe worse, or my name ain’t Sam Andrews.”

“Good gracious!” exclaimed Jack, “we’re in no fix to battle with a storm.”

As he spoke a sharp puff of wind shook the Flying Road Racer.

“Could we land if anything very bad comes on?” asked Captain Andrews, with a yet stronger tincture of anxiety in his tones.

Jack peered over the edge of the car.

“Nothing but dense forests are below us,” he said; “it would be courting death to try to land among them.”

In an almost unbelievably short time the wind had increased to a gale. It shrieked and moaned among the wire supports of the car, and the great bag that held it in mid-air swayed and tore furiously at its fastenings.

Jack kept a sharp lookout for a good spot to land, while Tom relieved Ned at the wheel. Once they saw beneath them a big area of smooth, park-like land, almost devoid of trees. It would have made an ideal landing place, but as they tried to force the Flying Road Racer around to head for it the full force of the wind struck them.

While traveling with the gale they had not noticed its full fury. Now, however, it battered them viciously, tearing at the gas bag as if it had been some monster bent on its destruction. The car swung wildly underneath its support, and they had to cling on to avoid being hurled out into space.

Their intention of battling with the wind was quickly given up. Tom brought the helm around and the Flying Road Racer hurtled off before the blast at a speed the indicator showed to be sixty-five miles.

“Is there no possibility of turning around and landing?” asked Mr. Jesson somewhat anxiously.

“It is out of the question,” declared Jack; “we’d rip this craft to pieces if we even attempted to buffet the storm.”

“It’s a bad one, all right,” said Abner Jennings.

“And may be worse afore it’s better,” said Captain Andrews, casting an anxious eye aloft at the scudding clouds among which they were sailing.

“The wind is blowing about sixty miles an hour,” said Jack, looking at the anemometer. “That means practically a hurricane speed.”

“Are we in danger?” asked Mr. Jesson.

“Not as long as we can keep in the air,” said Jack; “but if anything should go wrong it would be awkward, to say the least of it.”

“Then something may happen at any minute?”

“I didn’t say so. Uncle; but, as Captain Andrews said, the wind may grow stronger.”

“It’s hard to tell what these tropical hurricanes will do, once they get started,” said the burly captain. “I’ve seen ’em blow for a week and flatten out whole groves of cocoanuts.”

It grew blacker and blacker. The Flying Road Racer was now scudding through ragged white clouds that drove as fast as she did under a panoply of inky black. The scream of the rigging as the wind rushed against the taut, straining wires, sounded almost like the cries of some live thing in pain.

Every now and again there would come a sudden burst of vicious fury, and once or twice it actually appeared as if the great air craft would be ripped in pieces. But so far every wire and brace and turnbuckle in her construction had held bravely.

Jack watched the engine anxiously, attending to the lubricating devices and adjusting the gas mixers. The machine was behaving splendidly, and Jack felt that if only the connections between the gas bag and the car would hold they might still weather the fury of the gale.

He knew that these tropical hurricanes while furious are often not of very long duration. He stuck to his post, keeping hope alive in his heart, while the others pluckily enough endured the situation without flinching.

All at once, the wind stopped as suddenly as if it had been cut off at a gigantic spigot.

The calm, after that raging, furious gale, was positively startling.

“Is the storm over?” asked Ned.

“No. It’s only just beginning,” was the alarming response from Captain Andrews.

“I understand you now,” came from Mr. Jesson suddenly; “it’s a circular storm.”

“That’s it, sir. In a few minutes it will be blowing just as hard out of the west as a few minutes ago it was blowing from seaward.”

“We’d better put the craft about,” said Tom.

“Yes; bring her round as quick as you can,” said Jack. “Goodness! how queer this sudden calm feels.”

It was indeed an uncanny feeling. So still had the air become that a candle might have been lighted and its flame would hardly have flickered.

Through this stagnant atmosphere the Flying Road Racer was worked around till her bow was pointing seaward.

“Gracious!” exclaimed Tom, “if the wind doesn’t come from the quarter Captain Andrews expected we’ll be blown to bits.”

Jack said nothing. Any reply he might have made was, in fact, cut short at this moment by a moaning sound from the direction of the mountains. It was caused by the wind sweeping through the canyons and deep abysses that scared them.

“Put on full speed, Tom,” urged Jack; “the faster we are going when that wind strikes us the less chance there will be of our being ripped to bits.”

The greatest speed of which she was capable was placed on the Flying Road Racer. The indicator showed in turn fifty, sixty, sixty-five and then seventy miles!

Just as she attained this remarkable speed the wind struck the straining air craft with its full velocity.

“Fo’ de Lawd’s sake!” shrilled out Jupe, “we done bin gone dis time fo’ shoh.”

But he was wrong. The stout fabric of the wonderful craft withstood even the terrific assault now made upon her. But her forward motion suddenly ceased. Caught in the vortex created by the meeting point of the two conflicting storms, she was whirled round and round as if she had been gripped in a maelstrom of the winds.

The boys could do nothing to control this nauseating, dizzying, rotating motion. Upward and forward the Flying Road Racer was forced, climbing at terrifying speed the aerial circular staircase. One by one her occupants succumbed to the effects of the rapid circling. It caused a helpless, miserable feeling similar to seasickness and quite as prostrating.

“Back! back! Go down lower!” shouted Captain Andrews in Tom’s ear.

“We can’t,” yelled the lad; “we’re being dragged to the sky. We’ve lost all control.”

“Oh, but this is fearful!” exclaimed Mr. Jesson. “Nothing made by human hands can stand this much longer.”

Truly it seemed a marvel that the craft had held together as long as it had. So fast were they being swung round and round by this time that the car was suspended at quite a sharp angle, swinging outward from the gas bag by the force of the centrifugal motion.

It was terrifying, awe-inspiring, prostrating. Not one of those clinging for dear life to the dizzy car had ever had such an experience, and one or two among them had faced death not a few times.

All at once there came a sharp snap from above them.

To their overstrung nerves it sounded like a pistol shot.

“One of the wires has parted!” cried Ned in a terror-stricken tone.

“It is the beginning of the end,” groaned Captain Andrews, sinking his head in his hands.

“Can nothing be done?” gasped out Mr. Jesson, who alone of all that pallid-faced crew could find his voice at that instant.

“Nothing,” was the reply. “In ten minutes or less every wire holding us to that gas bag will have parted like that one.”

“And then?”

“And then, my friend, we shall be dropped five thousand feet through space.”

This dire prophecy was, however, not destined to be fulfilled. To the intense joy of the air travelers, the circular motion ceased almost as suddenly as it had begun, and the rest of the wires remained intact. Evidently, the Flying Road Racer had encountered a cross current of wind at the great altitude she had now attained, which brought her safely out of the aerial whirlpool.

It was an almost miraculous escape, and they were all duly thankful when once more their voyage was resumed on an even keel.

But the wind still blew hard, and it was impossible for them to stem it without running too grave a risk to attempt such a task.

In this way an hour or more passed, and then suddenly Jack, who had been looking out ahead, gave a startled cry.

“What’s the matter?” asked his father.

“Matter? Good heavens, we are being blown out to sea!”

While he spoke the Flying Road Racer was being hurtled along at a dizzy sped above bending tree tops and a storm-stressed expanse of country. Tom had brought the craft much lower, and it was now not more than five hundred feet above the earth. Beneath them the landscape whizzed by like a colored moving picture.

But the peril Jack had called attention to lay directly in front of them. Beyond the trees came a strip of white beach, and beyond that again the vast troubled expanse of the heaving ocean billows, lashed into fury by the storm.

Their situation was indeed critical.

“We’re going from bad to worse,” exclaimed Mr. Jesson. “Is there no way of landing?”

“Not without the risk of killing or injuring most of us,” rejoined Jack soberly.

“Why—why, then we’ll be compelled to fly above the ocean?”

“It looks that way. I don’t see what else we can do.”

“But in that case we shall be in grave danger?”

“I don’t think the danger will be much greater than the one we have faced. We have plenty of gas still, and can keep in the air for a long time if need be.”

“A week?” asked Captain Andrews. “These hurricanes sometimes last as long as that.”

“I don’t know that we could hold out for a week,” admitted Jack; “but I do know that we cannot avoid being blown out to sea. If the storm does not abate we are likely to be compelled to spend some time above the water.”

“Well, the wind is coming out of the southwest now. If we keep on this way we ought to be blown clear across the Gulf of Mexico and on to the western shore of Florida.”

It was Captain Andrews who vouchsafed this last remark.

“I don’t know that that would be a bad idea,” commented Professor Chadwick.

“How long ought it to take us, going at this rate of speed?” inquired Abner Jennings.

“Let’s see, the least distance across would be about fifteen hundred miles.”

“Then, at the rate we are being driven, it would take about twenty-four hours to make the passage,” calculated Mr. Jesson.

“About that time—yes,” agreed Jack. “I really think we had better try to do that.”

All agreed that it appeared to be the best plan. While they had been discussing this, they had passed over the last few miles of dry land. Looking down now they saw beneath them a vast expanse of gray, tumbling billows, tossing and rolling before the wind.

“If we ever took a tumble into the sea it would be all up with us,” commented Jack in a low voice to Tom.

“Yes; even a ship could hardly live in such a storm, and yet—look. Jack, back yonder,—isn’t that,—yes, surely it’s a craft of some sort!”

The lad indicated a point to the southward of them. Rising and falling in the great trough of the billows was a small vessel of some sort. For an instant Jack thought it was the Tarantula, but the next moment he made out that the vessel they were looking at had two masts and a yellow funnel amidships.

But another shift of the wind gave them something else to think of right then.

The blast “hauled round,” as mariners call it, and shifted to the south. The Flying Road Racer’s head was twisted around to the north and she was deflected from her course to the eastward and the hoped-for Florida coast.

“What shall we do now?” cried Ned Bangs, when he observed this.

“Keep on running before the wind. It’s all we can do,” rejoined Jack.

The storm-beaten air craft, with its heavy human freight, was now being driven almost due north along the coast. Tom kept the prow pointed so as to bring the course almost parallel with the coast. All the time both he and Jack kept a keen lookout for a possible landing place.

But none appeared. The wind, instead of dying down, grew stronger as the day went on.

“What will be the end of this?” was the thought that crossed the minds of all of them in one form or another.

The sun was obscured by scudding clouds, below them rolled the dismal, desolate expanse of salt water, for by this time they had passed over the peninsula of Yucatan and were out over the open gulf. In the distance to the westward, however, lay a dim coast line, and Tom steered toward it.

Suddenly there came a loud, ripping, crashing sound.

As he heard it Jack gave a cry of dismay. It was echoed by Tom and Ned, who both instantly guessed what had occurred.

The rudder had given way under the strain.

Looking over the side of the car they could see it being swept away by the wind, while astern of the tonneau hung a mass of tangled wreckage.

“Good heavens! This is the worst yet,” groaned Captain Andrews. “Adrift in an airship without a rudder! What under the starry dome can we do now?”

“Nothing but hope and pray for the best,” rejoined Jack. “We are helpless indeed without the rudder.”

Fortunately, however, the propeller still worked, and Tom, abandoning the now useless steering wheel, gave all his efforts to aiding Jack in attending to the engines.

The aerial screw helped to keep the Flying Road Racer on a straight course, and onward she flew, a disabled but still staunch craft.

“Is there anything that we can do to help you?” asked Professor Chadwick, after a while.

“Dere ain’t nuffin’ would help now but about a squar’ mile ob good dry lan’,” gloomily remarked Jupe.

Tom shook his head, and so did Jack.

“No, Father,” said the latter, “there isn’t a thing to be done. So long as we can keep the engine going, though, we can manage, at least, to keep before the wind.”

“We’re getting closer to the coast,” cried Mr. Jesson suddenly.

They were indeed. The forms of distant hills and forests could now be made out, and hope began to revive that they might, after all, find a spot to make a safe landing.

“The wind has shifted again,” announced Captain Andrews, glancing over Tom’s shoulder at the compass. “It’s blowing out of the east now, and if it holds will drive us upon the Mexican coast.”

Hardly had he made this announcement than there was an alarming cracking, snapping sound from the bow of the Flying Road Racer.

A dark, sharp-pointed object whizzed through the air, and the next instant there came a sudden sound of ripping fabric, followed by a hissing noise as of escaping steam.

“Great jumping sea serpents, what’s happened now?” bellowed Captain Andrews.

“A blade of the propeller has torn loose from its hub and pierced the gas bag,” shouted Jack in an alarmed tone.

“We’re falling!” suddenly screamed out Abner Jennings.

“Bound for Davy Jones’ locker, sure as fate!” bawled one of the sailors.

“Get out the life jackets!” yelled Tom at the top of his voice. “They are in that locker on the right-hand side of the tonneau.”

All this time the Flying Road Racer was slowly descending. The broken propeller blade had ripped a big hole in the side of the gas bag, through which the vapor was rushing forth.

“Isn’t it possible to repair it?” cried Mr. Jesson.

Jack shook his head.

“Impossible,” he said. “We had better all get on life jackets as quickly as possible. It’s lucky I had them put in that locker; but something I read about an airship being blown out to sea some months ago made me think of it.”

As quickly as possible all of them invested themselves in the cork-lined jackets, which were covered with stout canvas.

“Look! look!” cried Jack suddenly, “isn’t that an island ahead of us!”

Captain Andrews pierced the gloom with his keen eyes.

“It is! It’s an island, sure enough!” he cried joyfully. “If we can make it we are saved.”

But the Flying Road Racer settled lower even as he spoke.

The angry sea beneath looked savage and cruel as it leaped upward toward them, as if impatient for the end to come swiftly.

Ahead lay the island; a large one, with a sandy beach extending in their direction. Could they reach it before the air craft sank into the waves?

The engine had been shut off, and amidst a dead silence, so far as any talk was concerned, the Flying Road Racer drifted down toward the island.

But the gas had escaped so rapidly and the weight in the car was so great, that the island was still a few hundred feet off when they first felt the wind-driven spray dashing against their faces.

“Can we make it?” asked Mr. Jesson in a low, tense voice.

“I think so,” replied Jack; “at any rate, if we can’t, we have the cork jackets on and must swim for it.”

As he spoke, though, the disabled flying craft settled suddenly downward. Above her the collapsed gas envelope was wrinkled and flabby, and barely kept her up.

All at once the crest of a huge wave dashed against the bottom of the aluminum tank. The Flying Road Racer careened so far over that for a moment it looked as if her end had come.

But at the same moment the wind blew stronger and caught the half-empty gas bag. This raised the crippled craft a few feet and drove her forward. The impetus thus given was sufficient to save the adventurers from a dangerous swim.

With a crash that might have been audible at some distance had there been any one to hear it the Flying Road Racer landed in the sand of the island beach at precisely one-thirty on that day of stirring events in the young inventors lives.

Thanks to the shock absorbers, the auto part was not harmed seriously. Five minutes after they had landed the adventurers stood in a group surveying the stranded craft.

“What a wreck!” exclaimed Mr. Jesson, gazing the flabby wrinkles of the gas envelope and at the wound in its side.

The Flying Road Racer did, indeed, look different from the trim craft that had arisen from the deck of the Vagrant not so very long before.

But how much had transpired in those few hours! If time might be reckoned by events the boys could record that they had passed through years of experience since Jack and Captain Andrews struck out on the forest path leading to the plantation houses.

“What a mess!” breathed Abner Jennings, echoing in part Mr. Jesson’s remark.

“It’s my opinion that we ought to thank Providence for getting off with our lives,” said Captain Andrews stoutly. And to this sentiment they all heartily agreed.

“Can you ever repair her. Jack, do you think?” asked his father anxiously.

Jack, who had been surveying the wreck carefully, was not yet ready to give an opinion, however.

“If we could fix that rip in the gas bag it might be possible to patch her up,” he said dubiously. “There is,—or ought to be,—a spare propeller on board, and if the engine is working, it might be feasible to put the craft in order once more.”

“Well, we’d better run her up out of the reach of the waves anyhow,” said Tom.

The air craft had grounded at the margin of the beach, and the spray of the thunderous waves showered her as each broke.

The two sailors and the others came forward to lay hands on the Flying Road Racer, and shove her up the beach. But Jack had a better plan in mind.

“If the motor is working. I’ll run her up under her own power,” he said.

He followed up these words by getting into the driver’s seat, and after Tom had removed the wreck of the propeller, his cousin started up the engine and threw in the clutch connecting it with the driving machinery.

The rear wheels flew round in the sand for a minute, but as the boy applied more power they gripped the surface and the Flying Road Racer—an automobile now—moved rapidly up the beach. Jack ran her in under a grove of trees and then shut off the engine.

“If only we weren’t on an island,” he said, “we could run right through to the city of Mexico!”

“Gee, I wish we could,” said Ned Bangs, “it’s a question of how long the grub will hold out on this island, and we don’t know if any ships come this way.”

“Easy enough to find out,” said Tom rather carelessly.

“Easy enough?” echoed Ned. “Well, Tom Jesson, you’ll have to show me. Here we are, cut off from all communication——”

Tom smiled and shook his head.

“Not while we’ve got the wireless,” he said.

“What do you mean, Tom?” asked Mr. Jesson.

“That when I left the Vagrant I brought her wireless apparatus with me,” said Tom in a quiet tone. “That’s what those bundles were.”

“Good,” exclaimed Mr. Jesson. “We’ll have something to eat and some hot coffee, and then we’ll try to get into communication with the shore, or some vessel, and get them to take us off this desolate place.”

But Jack, who had been looking about the island in their vicinity, dampened their enthusiasm by a sudden question.

“How are you going to fix an aerial?” he asked.

“Easy enough,” said Tom confidently; “some tree will do. Ned Bangs, here, can climb it. Luckily I loaded a lot of copper wire with the other stuff. We can use that for antenna.”

“Why, you monkey!” cried Jack, half laughing, “there isn’t a tree on the island.”

This fact, which none of them had noticed before, was evidently so. The island was covered with a scrub growth, but nowhere did the bushes exceed a height of ten feet.

Professor Chadwick broke in on their dejection.

“Come,” he said, “it’s no use our discussing anything now. Let us have a good meal and then, maybe, we’ll hit upon some plan.”

While Jupe made his preparations for a warm meal, selecting a spot sheltered by brush not far from the remains of the Flying Road Racer, the boys gathered driftwood, of which there seemed to be plenty on the beach, and made a big pile of it. This was lighted, and the warmth of the blaze proved very comforting to the chilled castaways.

As Professor Chadwick had predicted, the meal served to put new heart into them. As they ate they discussed their situation in all its bearings, but without arriving at any conclusion as to their future course.

If they could not get a wireless message to some station on land or ship, their situation looked as if it might speedily become serious. They did not dwell on this aspect of the case, however, but made a determined effort to be as cheerful as possible.

After dinner, if such the meal could be called. Professor Chadwick and Mr. Jesson set out to explore the island. The others, except Jack and Tom, lay down to sleep, being’ thoroughly exhausted by what they had gone through.

The two lads, however, felt too excited to sleep. Instead, they fell to figuring how it would be possible to send out a message telling of their plight, without having a tall pole or tree to which to string their aerials.

The problem was perplexing, and they threshed it over and over for an hour without arriving any nearer a plan for getting their wires into the air. It was Jack who finally hit upon what was literally an inspiration.

Close to them, while they had been talking, lay the pile of life jackets they had taken off when they landed.

“Is there any of that liquid rubber for repairing the tires in the Flying Road Racer?” he inquired of Tom, with seeming meaningless curiosity.

“Why, yes; there’s a gallon can of it. But why?”

“You’ll see directly. Will you get it?”

“Yes, of course,” rejoined Tom, rising from his seat on the sand. “Anything else?”

“That needle and stout thread in the gas bag tool kit and—well, I guess that will be all for now.”

“I wish I knew what you are driving at,” said Tom, as he moved off to get the things Jack had asked for.

“I’m driving at a way to get those aerials up,” rejoined the young inventor briefly.

When Tom returned with the articles Jack had asked for, he found his cousin busily engaged in taking the cork out of one of the life jackets. This was easily done, as it was in granulated form.

Having emptied the jacket, the boy heated some of the liquid rubber over Jupe’s fire till it was about the consistency of cream. This done, he proceeded to coat the canvas of the empty life jacket with the compound. Before he did this, however, he sewed a patch on over the hole he had made to drain the cork, leaving a bit of rubber tube, also found in the supply locker of the Flying Road Racer, sticking out.

Tom, after a few minutes, began to realize dimly what the ingenious lad was doing; but he didn’t get the full understanding of Jack’s idea till the latter, having allowed the rubber coating to dry, walked toward the Flying Road Racer with it.

“I see what you’ve made now. Jack,” he cried. “It’s an airproof canvas bag, and you’re——”

“Going to fill it with gas and see if it will rise,” said Jack.

As he spoke he placed the end of the rubber tube he had left protruding from the canvas life jacket, over a small stop-cock on the gas tank of the Flying Road Racer. When he turned the valve a hissing sound followed and the rubber-coated life jacket began to fill, just as any air-tight envelope would have done.

When it was half full a laughable thing occurred, giving abundant evidence of the bag’s buoyancy. Jack, who was holding it, was suddenly lifted off his feet as the bag began to rise, tearing the end of the rubber tube off the valve as it did so. Just as he was lifted into the air, for he actually couldn’t make up his mind to let go of his invention, Tom seized his feet and dragged him to the sand again. A rope was secured and the bag lashed to a bush after the end of the tube had been tied.

“By cracky!” cried Tom, “that’s the invention of the century. How on earth did you come to think of it?”

“I suppose old Mother Necessity had something to do with it,” said Jack; “but the fact that those life jackets lay right close to us helped a lot. I reasoned it out that they would float on the water, and therefore, if they could be emptied and made air-tight, they would rise when filled with gas equally well.”

“And you’re going to hitch the aerials on to that one and send them up?”

“I’m not sure that one of them will be enough to raise such a weight of copper wire. I guess we’ll make another one.”

“And I’ll help you,” cried Tom enthusiastically.

Half an hour later when Mr. Jesson and his brother-in-law returned from exploring the island, which they had found to be a desolate spot some five miles off shore, they found two busy lads.

The wires had been strung on “spreaders” cut from the brush. Then one of the ends was connected to each of the buoyant “balloons” that were to carry the antenna aloft.

In the lee of the Flying Road Racer the boys had arranged the wireless equipment, and were now occupied in securing the lower end of the antenna and adjusting the connecting wires from aerials to the instruments.

At last all was ready, and the two canvas “balloons” were cut loose. Slowly but steadily they rose, carrying with them the strands of copper wire,—five of them, each one hundred feet in length. The wind had died down quite a lot, and there was not much strain on the wires as they were pulled skyward like the string of a kite.

As the wires tightened and became extended to their full length the boys broke into a cheer. Held by the captive “balloons,” the five parallel wires made as effective an aerial as if they had been rigged to a lofty pole.

“Boys,” exclaimed Professor Chadwick proudly, “that’s what I call a real wireless triumph!”

“Wait and see if it works first, father,” said Jack, with a happy smile. He had not much doubt on this point, having solved the vexatious problem of getting his wires aloft.

“What are you going to do now?” asked Tom of Jack, who, with the receivers clamped over his ears, was seated at the wireless apparatus.

It was the middle of the afternoon, the storm had blown itself out and the sun was shining cheerfully.

About the young inventors pressed the castaways,—for they had been awakened,—Captain Andrews, so that he might make an observation and get their exact position, and the rest to be on hand if need arose.

Jack had just flashed out the location of the island, and with it a fervent appeal for help. From the balloon-supported wires above him, the message had gone shooting forth into space.

But as yet no answer had come, though the lad sat with the transmitting switch open, waiting for a reply.

“Maybe there are no ships in this part of the Gulf,” said Tom.

“Well, with the power we have from that dynamo we ought to have gotten into communication with something before this,” said Jack impatiently. He turned his head toward the dynamo of the Flying Road Racer, which had been connected with the wireless apparatus and was whizzing away merrily. The motor, fed by a fresh supply of gas obtained by dumping in a new lot of crystals, of course supplied the motive power for the current maker.

“Try again,” suggested Professor Chadwick.

Jack threw over the switch to connect the transmitting appliances, and began manipulating the key once more.

The message of distress crackled and flashed, like the snapping of a whip lash,—or, more truly, a thousand of them.

Jack was utilizing every atom of power he could obtain. He calculated that he had at least one hundred and ten volts of current, which should be ample to send his messages for a great distance.

After sending for a while he stopped and listened. But no message came beating against his ears, breathing a spirit of hope.

“Try sending out a C. Q. D.,” said Abner Jennings.

“You mean S. O. S.,” rejoined Jack. “C. Q. D. isn’t used as an urgent call any more. Too many would-be jokers used to send it out and cause endless confusion.”

He threw the switch again into a sending position, and began to flash out another message.

“o o o —— —— —— o o o” “S. O. S.”

It was the most urgent call known to seamen. The despairing cry of the wrecked the lost.

Again and again Jack volleyed it out, and the far-flung appeal went skyrocketing off on the electric waves, spreading like the ripples on a pond from the tightly stretched aerials. It was signed “The Chadwick Party.”

Then the lad tried listening again.

Suddenly a look of joy flashed over his face.

“He’s getting an answer!” yelled Tom in huge excitement. Ned Banks, hardly less enthusiastic, capered about.

Jack’s pencil traced the message from space on a pad of paper placed on an empty box before him.

“What is it? What’s the matter?”

Once more he began sending furiously.

“We have been driven on a desert island off the Mexican coast.”

“Where is it?” came the reply. “Give latitude and longitude.”

Jack swiftly flashed back the required information. Then he asked a question.

“Who is this?”

“The Sea King,” was the astonishing reply.

“We are coming to your aid. Have you got the gems?”

“Yes. They are safe, and we are all well, but in need of help,” the lad sent back with a joyous heart.

He listened for a reply, but none came. In fact, there was no need for more communication. The castaways knew what they wanted to know most of all, namely, that they would be taken off the island as soon as possible. In the meantime. Professor Chadwick ordered Jupe to prepare a royal spread in celebration of the event.

“We look like a lot of pirates,” commented Jack, as, after a hearty meal, they lay stretched about the fire.

“I suppose that, like most boys, you have a sort of admiration for those gentry?” inquired Captain Andrews.

“Well, he’s stuffed his head with enough books about them,” chuckled Tom.

“Guess that applies to you, too,” parried Jack, with a grin.

“I don’t suppose, though, that either of you ever saw a real pirate,” commented the captain quietly. “I can tell you they are mighty different beings from the red-sashed, romantic sort of chaps you read about.”

“Why, have you ever seen any?” asked Jack, sitting up eagerly.

“Yes, and fought with ’em, too. Care to hear the yarn?” responded the seaman.

The boys’ prompt affirmative removed all doubts on this score and Captain Andrews, without further preliminaries, struck into his tale.

“It was a good many years ago,” he said, “when I wasn’t much bigger than you lads. But for all that I was acting as third mate on a sailing packet running from Liverpool to the West Indies. The skipper, whose name was David Munson, was a stern man, but kind enough. He had a curious way of keeping to himself, though, and the men said that some time before he had been attacked by sea-robbers, who had cut him down and captured his wife and child, who sailed with him. But the rascals had not thought it worth while to take him and left him for dead on his burning vessel. For they, according to their usual custom, had set it on fire before they sailed away.

“Captain Munson recovered consciousness in the nick of time to stagger out of the path of the flames. A boat lay astern of his craft and he had just strength enough left to slide down a rope into this and cast off. Then he lost consciousness once more.

“For three days he drifted in this way, lying all the time in a dead swoon. On the third day he was picked up, more dead than alive, by a Bristol line clipper, which brought him back to England.

“It was many a long day before he got about again and it was then found that he had lost all recollection of the tragedy and appeared to think that his vessel had perished in a storm. But, except for this, his mind was clear enough and he found little difficulty in getting a new command. This was the West Indiaman Cambrian Hills, of which I was third mate. Captain Munson’s story was related to me by the first mate, a man named Sterling, a fine seaman and a good fellow. This Sterling had been on board the ship that the pirates had captured and had been made prisoner by them. But later he had managed to make his escape from the South American city to which they had taken him to be sold as a slave.

“Reaching England, he found that his former skipper, whom he had thought dead, was alive and in good health, but that his mind was hopelessly clouded as to the past. In fact, he did not recognize Sterling, and Sterling, fearing the consequences of reminding him of what had occurred on the Spanish main, made no move to awaken his slumbering memory. This was the strange story Mate Sterling told me one stormy night on watch.

“Well, on this particular voyage the Cambrian Hills came in for the buffeting of their life. Heavy gales, head seas, and violent squalls beat the craft about day after day. And at last up came a terrific gale from the northeast, which carried us away off our course and down off the coast of Brazil.

“Now, as it so happened, this was the very worst place we could have been driven to at this particular time. One of those little wars that were then eternally harassing the South American republics had just come to an end and the seas thereabouts were swarming with piratical craft. These gentry called themselves privateers and carried government papers, but were, to all intents and purposes, pirates and nothing more nor less.

“Following the gale, the weather fell into a regular condition of doldrums. Sometimes it blew a light wind, but more often a dead calm till it seemed that we were doomed to haunt the Brazilian coast for the rest of our lives. The men grew restive. It was insufferably hot and the calking in the deck seams fairly bubbled and boiled.

“Thus passed an entire week and the only man or board whose nerves were not on edge was Captain Munson. He appeared not to worry or chafe over our situation in the least. This was the more curious, inasmuch as Sterling had informed me that the seas in which we lay were the very identical ones in which the fatal battle with the pirates who had looted Captain Munson’s last command had taken place.

“One morning just after breakfast I was standing against the taffrail, with Sterling by my side, idly gazing horizonward for a sign of coming wind. All at once I saw Sterling clap his telescope to his eye and gaze intently off into the southeast.

“‘Wind?’ says I.

“‘No,’ says he.

“‘Well, what then?’ says I.

“‘A sail,’ says he.

“‘Then they must be getting more wind than we are,’ says I. ‘What do you make her out to be?’

“‘Can’t tell yet; but somehow I don’t much like the look of her.’

“He handed me the glass.

“‘Take a look yourself,’ he said.

“I squinted through the telescope and at last made out the distant sail. She was a black brigantine, low in the water and with a rakish sort of look about her masts and spars. The water over around her was dark blue—of a deeper tinge than the ocean surrounding us—showing that the wind was blowing off in that direction.

“‘She doesn’t show any colors,’ says I, handing the glass back to Sterling. ‘What do you make her out to be?’

“He shrugged his shoulders.

“‘I don’t know, laddie,’ he said, ‘but she looks to me like a war vessel of some sort. Maybe a Brazilian craft.’

“‘Well, whatever she is,’ says I, ‘she’s got the wind with her and it’ll hit us in a minute.’

“‘That’s right,’ says he, coming out of a sort of a reverie. ‘Get your yards squared and your courses braced up.’

“I hastened to put these orders into execution, and hardly had they been completed when the long awaited wind struck us. The Cambrian Hills heeled over and began to move through the water.

“The crew set up a cheer as we began to get under way and the noise brought the skipper on deck. He looked more than usually grave and had a Bible, which he had evidently been reading, in his hand.

“‘Wind at last, Mr. Sterling?’ he said quietly.

“‘Aye! aye, sir,’ said the mate. ‘I knew the luck was bound to turn,’ he added.

“‘There is no such thing as luck, Mr. Sterling,’ said the captain in his quiet, grave way. ‘All is the doings of Providence.’

“Then he turned and moved away, but Sterling was at his side in a minute.

“‘There’s a sail off there to windward, sir. Will you take a look at her and tell us what you think of her? You know it pays to be suspicious in these waters, and I don’t much like her looks.’

“In his usual serious manner the skipper took the glass and gazed through it at the brigantine, which, to my eye, was sailing two feet to our one, and overhauling us fast. He gazed at her a long time and when he set the glass down his face was working curiously. He clapped his hand to his forehead as if something there hurt him.

“‘I—I—There’s something strangely familiar about that craft, Mr. Sterling,’ says he, ‘but, for the life of me, I can’t tell what it is.’

“‘Looks to me like a man-o’-war of some sort, sir,’ says Sterling.

“He took up the glass again and scrutinized the stranger. Then I saw the color begin to die out of his red, good-natured face till it grew white as a corpse.

“‘It’s an armed vessel, sir,’ he grated out through his clenched teeth, ‘and—and she’s just broken out the Black Flag,—the skull and cross bones, sir!’

“‘A pirate, eh?’ said Munson quietly, and I noticed the same curious expression pass across his face. It was the strained look of a man trying to recall something that eludes him persistently. ‘Well, Mr. Sterling, she’s faster than us. We must fight for it, sir,’ he said at length.

“‘Aye, sir,’ says Sterling gravely, ‘I’ll call the men aft and explain to them. Andrews, my lad, you attend to distributing the weapons.’

“Every West Indiaman in those days carried a small arsenal of weapons—blunderbusses and cutlasses—for attacks by roving bands of sea-robbers were not infrequent. The men took the news well enough, although one or two of them went white. But there were enough old veterans among them to keep them steady and prevent a panic.

“I guess the resolute bearing of Captain Munson and Mr. Sterling had a good deal to do with putting heart into them. As for myself, I was horribly scared inside, but I trust that my alarm did not appear too conspicuously on my countenance.

“The men gave a cheer as Captain Munson concluded his little speech and I summoned three of them below to assist in the distribution of the arms. In the meantime Mr. Sterling gave orders to the men to rig up as many dummies as possible and station them along the bulwarks so that we might seem to be more in number than we actually were. This was a common enough trick in those days.

“I have to smile even now when I think of it, but one good fellow in his zeal even clapped a cap on top of the galley chimney, although what a man would have been doing poking his head out of ‘Charley Noble’—as the cook-house stack is called by seamen—is hard to say. By the time all our preparations were completed the craft that was overhauling us was not more than half a mile astern.

“She was a handsome craft and a witch at sailing. The Cambrian Hills was accounted a fast vessel; but we weren’t in it with our pursuer. If we had had any doubt as to her intentions toward us till then she soon dispelled it. From her bow came a flash and a puff of smoke and a ball screamed through our rigging. It did no harm—wasn’t meant to, probably—but it showed us that they ‘meant business.’

“The Cambrian Hills carried an old brass cannon, more for saluting purposes than anything else. But we had slugs on board and the piece of artillery was loaded up. But the enemy, as we now rightfully regarded her, was too far off for our carronade to be effective as yet. She, on the other hand, appeared to have a serviceable heavy gun. All this was not encouraging, but the prospect grew worse as we swept their decks with the glass. Fully forty men lined her bulwarks and we numbered only twenty, including the cook, who was not accounted a first class fighting man. Of him, however, more anon.

“I was a young fellow then and had always thought of pirates as being chaps all covered with finery, gold lace and jewels and such. I was stricken with astonishment to see that no such men appeared on the brigantine. They were all filthy, wretched looking things, many of them being coal-black negroes. Among them were even one or two Chinese. Such a mixture of races I never saw before or since.

“Suddenly Captain Munson, to my astonishment, snatched up his speaking trumpet and hailed the pirate, who was now almost alongside and to windward.

“‘Ship ahoy!’

“His voice was as bold as if he had been skipper of a man-o’-war hailing a sea criminal. It was a bold move, but it was successful in producing some confusion among the pirates. All at once a giant of a man with a black beard stepped up on the pirate’s rail, holding on by the lee forestays.

“‘Hullo!’ he hailed in a foreign accent.

“‘What ship’s that?’ hailed Captain Munson again.

“‘None of your business. Heave to. I want to board you,’ was the reply in an insolent voice.

“‘You go plumb to blazes!’ came from Sterling, who was a hot-tempered chap and could contain himself no longer.

“At that very instant a puff of wind blew the man’s black beard aside. He clutched at it desperately, but somehow he bungled the job, and to my utter astonishment—it came off! He stood revealed as a man of huge frame with a brutal bull-dog jaw and unmistakable Latin cast of features. But I had little time to notice this, for a strange cry had broken from Captain Munson’s lips as the man’s disguise blew off. He turned deathly pale and staggered like a drunken man.

“Sterling and I rushed to his side. We thought for a minute that he was about to faint. But he rallied and stared at us for a moment wildly.

“‘Good Lord!’ exclaimed Sterling, ‘it’s all come back to him!’

“Then I understood. That man who had hailed us was the captain of the same piratical band that had attacked Captain Munson’s other ship and carried off his wife and child. The next instant following Sterling’s exclamation was a dramatic one.

“‘You know me, sir?’ asked the mate.

“‘Yes! Yes! You’re Robert Sterling,’ burst from the captain’s lips. ‘I recall it all now. The fight! That ruffian struck me down. I woke up to find you all gone. But, Sterling, how do you come to be here,—and—and where are Bess and the baby?’

“I felt sorry for Sterling then. His face went as white as the captain’s visage and he actually shook as if from cold. But he had to answer.

“‘Better off than if they were in the hands of those ruffians, sir,’ he replied in a low voice which shook perilously, ‘they are——’

“‘Dead!’ burst out the captain, with a terrible cry.

“Sterling bowed his head.

“‘Your wife leaped overboard rather than be sold down the coast as a slave,’ he said slowly, ‘and—and she took the baby with her.’

“I did not dare to look at Captain Munson’s face. But I could hear his breath come short and quick, just like a man breathes after a long, hard swim. But the next instant we had other things to think of. A volley of small arms from the pirate craft whistled about our ears. She was up to windward and evidently meant to grapple and board us. What followed is hard to describe. I don’t know how most men feel in a fight of that character, but it seemed to me that I was in a dream. I fired and loaded, and fired and loaded, while all about me bullets were flying and fallen men groaning. Splinters flew as the pirate’s volleys raked our rails. I was suddenly conscious of being wounded, but I fought on, actually hardly knowing what I was doing.

“Suddenly the pirate’s sails loomed close alongside. Our yardarms locked with his. Grappling irons were thrown aboard us and the whole horde of ruffians tried to board us by main force. But they met with such desperate resistance that they were compelled to retreat for the time. Right here is where the cook figured. Just as things looked most critical he turned the tide for us. Attached to a huge boiler in his domain was a hose, used for washing stains out of the decks.

“While we had been arming he had made up a roaring fire. By the time the pirates boarded us there was enough boiling water in the boiler to make that hose an effective weapon. Yelling like an Indian, the cook turned it on the scrambling mass of rascals. The stream of boiling water was more effective than bullets. With yells and cries they fell back, some of them scalded horribly.

“All this time I had lost sight of Captain Munson. Now I glimpsed him, just in time to see him leap into the main chains and from thence on to the bulwarks of the pirate ship. His face was fixed and terrible and held an expression of desperate resolve. Cutlass in hand, he fought his way through the demoralized pirates and at last I saw, in a flash of understanding, his purpose. His object was to find out, and kill with his own hands, the pirate chief. Hardly had I realized this before the men encountered each other. Apparently the pirate recognized Munson instantly, for I saw him recoil as if he had seen a ghost. But the next instant he had recovered and began to fight desperately for his life.

“In the meantime some of our crew had cut the two vessels apart, and before any of us recovered his wits and started to the captain’s rescue the two craft had drifted so far asunder that it was impossible. With horrified fascination we watched the fight, and if it held us spellbound it appeared to have the same effect on the pirate crew; at any rate, none of them interfered.

“Such a furious fight could not, in the nature of things, last long, but it came to an altogether unexpected conclusion. Captain Munson’s cutlass had broken off short and he closed with his enemy, grasping him about the waist. They both reeled backward—and suddenly vanished from sight. A hatchway had been left open, and in their blind fury neither had noticed it. Tripping on the coaming, they had plunged into it.

“Suddenly we heard a shot from the pirate craft, and then came a great cry. I could not make out what all the yelling was about, and turned to Sterling who seemed equally spellbound at the horror of the thing we had just witnessed.

“‘What is it? What are they saying?’ I demanded.

“‘They are shouting that the magazine is on fire!’ he exclaimed, ‘that a shot fired by the Englishman has ignited the powder!’”

“The words had hardly left his lips before a hot blast rushed full at me. I was knocked from my feet, saw a vast sheet of flame before me, and knew no more. When I came to I discovered Sterling bending over me. His face was very grave and serious.

“‘What has happened?’ I asked weakly.

“‘The pirate ship is blown up,’ he replied; ‘not a vestige of her is left.’

“‘And Captain Munson?’ I demanded, although I knew what the reply would be.

“Sterling removed his cap; a last tribute to a brave man.

”‘Has gone with her to Jones’ locker,’ he rejoined; ‘maybe it was better so. It would be just about here that his wife and baby died.’”

Captain Andrews paused. So ended his story, which cast a gloom over the party that was not to be dispelled. Soon after, therefore, they retired, with the picture of the sea captain’s tragic death still vividly before their eyes.

Before joining the others. Jack tried to get into communication with the Sea King by wireless once more. But he failed. However, this did not worry them, as they knew that their friends must know where to find them.

“I wonder when they’ll arrive here,” said Professor Chadwick, as they prepared to spend as comfortable a night as they could on the sand. “Those repairs were surely effected quickly,” he added.

“Very quickly,” said Captain Andrews, who alone of the party had not been almost wild with delight at the prospect of the rescue. “By the way. Jack, you are quite sure that it was the Sea King that you were in communication with?”

“Of course,” rejoined the lad rather impatiently, “who else could it have been? Who would have had any object in trying to pass themselves off as the Sea King unless they——”

He stopped short and looked rather blank all of a sudden. The idea of Herrera had just crossed his mind. And then that ship that they had seen laboring in the stormy sea that afternoon?

“Pshaw!” said the lad to himself; “she had two masts and a yellow funnel, there’s no chance of that being the Tarantula.”

When he voiced this belief aloud later on, the others agreed with him. But Captain Andrews, still suspicious, determined, he said, to keep watch. The others, almost too tired to keep their eyes open, rather ridiculed this precaution, and soon sleep enwrapped every one on that desolate island.

Every one? Yes; for tired nature had asserted herself and Captain Andrews, after a hard struggle to keep awake, dozed off, woke with a start, dozed off again and finally slumbered profoundly.

Had he kept his eyes open a while longer he would have seen something approaching the island that would have caused him to keep awake with a vengeance. This object was nothing more nor less than the Tarantula, disguised cunningly by a canvas smokestack painted yellow, and two masts.

Herrera early that day had ascended the river and heard of the flight of the prisoners and the destruction of his hemp-drying plant. Half crazy with fury he kept a watch on the skies and saw the Flying Road Racer, high in air as she was driven seaward after her perilous experience in the circular storm.

In defiance of the wild weather he at once prepared to put to sea disguising his ship, as he had done on other occasions, as she dropped down the river.

Me had seen the storm-racked air craft as she flew above him. He had observed her, in fact, at the very moment that the adventurers espied his tossing craft. To his chagrin, however, she passed out of sight. But he held on in the direction she had vanished determined not to give up the chase of those precious stones till he had exhausted every means of trying to obtain them.

Just as he was despairing of ever hearing of the Flying Road Racer again. Jack’s “S. O. S.” message had come winging across the sea. As soon as his operator gave him the despatch the rascal conceived the daring plan of impersonating the Sea King and in this guise he flashed back the message inquiring the position of the castaways. He took care to ascertain that the gems were safe.

While profound and peaceful sleep wrapped the party of adventurers, a boat landed on the beach, crowded with men. It came from the Tarantula, which had anchored about two hundred yards to seaward. Every man was armed and among them was Herrera with one or two of his chosen aides.

Their plans had been formed before they landed and they silently sneaked up on the castaways’ camp. They were agreeably surprised to find no sentries posted.

According to previous plans, each man of the crew carried ropes and gags. The sleeping party was surprised without warning and tied and gagged without a chance of their presenting any opposition. Each of the Chadwick party, as they awakened under the rough handling of the henchmen of Herrera, was given a strong hint not to resist, in the form of a pistol barrel pressed to the nape of his neck.

As resistance would have been worse than useless all submitted quietly to the outrage, and Herrera’s triumph appeared to be complete. When they all had been secured the marauders commenced a frantic search for the great silver jewel casket. They found it without much difficulty under the professor’s coat which he had used as a pillow. Not expecting any attack he had not taken much pains to conceal it.

Herrera burst into a loud laugh as he opened the casket and took out the three great flashing stones it contained.

“So you thought that you could trick Herrera, eh, you stupid Yankee,” he snarled, “but I caught your message by wireless, you dogs of gringos. I spit on you and despise you. The jewels you thought to steal are now mine. But see—Herrera is generous. He leaves you the box!”

As he spoke the ruffian flung the silver casket to the sand and then, with some gruff orders to his men, strode off across the beach. A few minutes later the splash of oars informed the marooned castaways that their foe had departed taking with him the gems they had gone through so much to save intact; and not only that, he took with him also their hopes of being rescued. From what he had said about the wireless, it was clear that he had intercepted the message for aid, and thus been guided to the island. The Sea King had not received word from them at all.

With what bitter feelings they reviewed the situation may be imagined. And it did not relieve the misery of their present position, as they lay gagged and helpless, to reflect that if they had kept a guard, the disaster might not have happened. They had been trapped like so many unthinking children.

Jack struggled and strained at his bonds, as, in fact, all the rest of the party were doing. To his delight, after a brief period of struggling, he managed to loosen them considerably. The work of tying up the party had been done hastily, and, consequently, the knots were not very hard to loosen. In fact, all that Herrera had wanted, was to keep them quiet till he had looted the treasure of the gems.

When Jack had worked his hands free he pulled the gag out of his mouth, and then, after undoing his ankle bonds, he drew out his knife and rapidly liberated his companions.

“Well, a fine mess I’ve made of it,” grumbled out Captain Andrews, as soon as he was free.

“I don’t see that you were any worse than the rest of us,” said Professor Chadwick; “in fact, it was you who had a keen enough mind to guess that our message might have been received and answered by another craft than the Sea King.”

“Which it was,” put in Mr. Jesson.

“Yes; but I kept watch for a while,” contritely said the captain, “and—I’m bitterly ashamed to say it,—I fell asleep at my post of duty.”

“For which we don’t attach a bit of blame to you,” said Professor Chadwick; “what we had passed through was enough to exhaust a giant. To tell you the truth, I almost feel relieved now that the gems are gone.”

“The natives had a legend that they brought bad luck,” said Mr. Jesson, “and indeed they seemed to.”

“I hope they bring evil fortune to that greaser who has them now,” struck in Abner Jennings.

The two sailors added their growling assent to this wish, nor could any of the party refrain from echoing it.

[Illustration: Jack liberated Captain Andrews.]

“I suppose he’s got clear away,” hazarded Ned presently.

“Of course he has,” grunted Captain Andrews. “I’ll bet there’s twenty miles between him and this island right now. And, incidentally, I’m ready to bet as to his future.”

“What will it be?” asked Jack, with some curiosity.

“Why, he’ll throw up his governorship,—the Diaz government is on its last legs, anyhow,—and skip out to Paris. He’ll sell those gems over there and—live happy ever afterward.”

“Why Paris?” asked Mr. Jesson.

“Oh, all those scallywags go over there when they’ve made their graft,” laughed Ned; “they won’t tolerate them any other place, I guess. When I was over there with my folks two years ago we saw more princes and exiled presidents from South America than you could shake a stick at. You couldn’t have thrown a brick on the main boulevards without hitting some ruler who had left his country for his country’s good.”

“All of which disquisition,” said Professor Chadwick dryly, “doesn’t solve our problem.”

“No, indeed,” said Mr. Jesson; “we are as badly off as before.”

“Worse,” exclaimed Jack.

“How’s that?” asked Tom.

“Well, haven’t we lost those gems?”

“Oh, bother the old gems,” said Tom, “we’ve got the box, haven’t we? If any one in the States doesn’t believe we ever had the three gems we can show them the casket as proof that we really did have them once.”

As he spoke he picked up the box from the sand where Herrera had flung it, and handed it to the Professor.

“It will make a handsome relic of our trip at all events,” said that gentleman, with half a sigh. “I guess I’ll present it to some institute interested in such things.”

“Pity those bumps on the cover aren’t precious stones,” said Ned, indicating the three dull-colored knobs on the cover. “Wonder what they are there for?”

“To make the box look nobby,” ventured Tom, a pun which almost cost him a clip on the side of the head.

But they were soon recalled to the seriousness of their situation. In the east the day was beginning to dawn, and a return to sleep was out of the question after all that had occurred.

“I guess I’ll get to work with the wireless,” said Jack, “it’s our only hope.”

“Unless we could swim ashore,” said Captain Andrews. “It isn’t more than five miles off.”

“True. But from what we could see yesterday it is a rugged, inhospitable shore,” said Mr. Jesson.

“Most anything would be better than this, though, so long as it was the mainland,” said Ned.

“Yes, if only the old Flying Road Racer would have kept in the air half an hour longer,” groaned Tom, “we might have used her as an auto to reach some civilized spot.”

“We could easily have done that,” struck in Jack. “The engine and running gear are in perfect order. So far as that is concerned, she is ready for a road trip of a thousand miles right now.”

“You ought to have fixed it so she could swim, while you were about it,” said Ned.

He meant the remark as a joke; but Jack answered quite seriously.

“I’ve been thinking over such a plan,” he said; “maybe some day I’ll get to work and invent something that will make the good old craft as capable in the water as she is on land and in the air.”

“Wish you could invent it right now,” began Ned with a laugh. “I——”

He stopped short with a puzzled look, which, oddly enough, was reflected on all their races the next moment.

“My legs are wobbly!” cried Tom.

“By the trident of Neptune,” roared Captain Andrews, “so are mine!”

“It’s not our legs!” cried Mr. Jesson, “it’s the ground that’s moving!”

“The whole island is quivering like jelly!” cried Ned.

“Good land, what ails de place? It’s done got chills and feber!” shouted Jupe from his pots and pans, which were now rolling in every direction.

The tremor grew stronger. Accompanying it was a queer, moaning sort of sound. All at once there came a violent convulsion, and they were all thrown flat. The roaring noise increased till it was almost deafening.

“It’s an earthquake!” called out Professor Chadwick.

“An earthquake?” cried the others in terrified tones as they rolled about.

Suddenly, not far from them, a great ragged fissure yawned in the earth and almost instantly closed again. From that moment, for the ensuing ten minutes, the castaways were in a condition bordering on panic. With the very earth under their feet refusing them support they felt that they were, indeed, in a sorry plight.

At the conclusion of the period of time mentioned, the shocks stopped as suddenly as they had begun.

“Do you think there’ll be any more of them?” asked Tom in rather a quavery voice.

“Impossible to say,” said Mr. Jesson. “I imagine that this is a continuation of the one that caused that cliff to collapse, which resulted in my escape from those Indians.”

“I suspect that is it,” said Professor Chadwick. “The great storm may have also resulted from the generally disturbed conditions. We may have no more shocks and we may have a dozen.”

“I’ve known cases of whole islands being swallowed in the South Seas——” began Abner Jennings gloomily.

But Professor Chadwick stopped him.

“If you can’t talk of something more cheerful, my man, don’t talk at all,” he said.

“And tidal waves, too, that wiped out whole cities like Galveston,” muttered Jennings, in a low tone, however.

“There is no reason to expect that another shock will occur,” resumed the Professor; “the very nature of these seismic disturbances results in——”

“Wow! Glory to Goshen, here comes annudder one!” bellowed Jupe, dropping a frying pan with a clatter and throwing himself flat on his face.

The others followed his example. Indeed, it was impossible to remain on one’s feet. The mighty earth waves undulated like the billows of the sea.

This shock lasted longer than the other, and was more severe. When it was over they arose to their feet considerably unnerved by the convulsion of nature.

“Do——do you think there is any danger of this island sinking. Professor?” asked Ned in a shaky voice.

“I do not,” rejoined the other with a confidence that he was very far from actually feeling, however. “I see no evidence of any volcanic formation hereabouts.”

“Maybe de ole Mudder Earth done got a bad tummy ache,” hazarded Jupe.

“I wish she’d get it in her foot, then,” grumbled Ned. “I don’t—say, Jack,” he broke off suddenly, “am I seeing things or is that beach narrower than it was?”

A worried look passed over Jack’s face.

“I’m afraid your eyesight is all right, Ned,” he said. “The water is closer than it was, beyond a doubt.”

“And that means?” gasped Captain Andrews. “That we are sinking,” calmly said Professor Chadwick. “There is no use deceiving ourselves. Jack, send out a call for aid. There may be a chance of some ship catching the message.”

Jack sent an appeal flashing forth from the wireless. Then he listened as usual for an answer.

It came, but not in the way he had expected. He flung the receivers from his ears with an angry expression.

“It’s that rascal Herrera,” he said. “He intercepted the call.”

“The villain! What did he say?” demanded Mr. Jesson.

“He said that we could stay here till the island sank, for all he cared, and added that Diaz had been driven out of Mexico, and that he was off to Europe with those gems.”

“Dat dere coffee-colored man is de worst no ’count trash I ebber done heard of,” announced Jupe solemnly, while the others stood thunderstruck at such pitiless behavior.

Before they could utter a word of comment, however, another shock struck the island. And this time it caused an amazing thing to happen. The centre of the isolated spot of land had been quite an elevation. During this spasm of the earth, however, an astonishing change took place in the form of the island. The “crown” of the sandy little place sank until it was depressed into a sort of cup. On the outer rim of this odd subsidence of the island, were the adventurers who looked with alarmed eyes on this freak of the earthquake. It mean only one thing, and that was that if another shock occurred and the land sank any further, that the sea must overwhelm it utterly.

While they were still looking over the altered scene. Captain Andrews gave a shout.

“Shiver my timbers,” he cried, “look yonder, will you?”

The subsidence of the centre of the island, of course, gave them a clear view of the distant shore and of the neck of water between it and the island.

An astounding thing had happened, as the adventurers could now see. Although they had not known it, the island had once formed part of the mainland, and a narrow neck still connected it at a depth of only a few feet at low water. It was now low tide, and the earthquake, while it depressed the central part of the island, had performed a still more astonishing freak.

It had raised this narrow neck linking it to the shore till it was quite a few inches above the level of the water, making a causeway of wet sand between the island and the mainland!

Jack was the first to grasp the significance of this. He gave a glad shout as he did so.

“Hurrah! We are saved!” he cried. “The earthquake has saved us!”

“What?” demanded his hearers, not quite so quick-thinking as Jack.

“Don’t you see?” exclaimed the boy. “We can drive the Flying Road Racer ashore over that neck of sand as easily as if we were taking a spin in the park.”

“But suppose another shock causes the neck of sand to subside again?” asked Mr. Jesson skeptically.

“We must take our chances of that,” Tom answered him. “In any case, it means death to remain where we are.”

As Jack spoke, the island gave another trembling shake. It was only a slight one, but it warned them that, in all probability, there were to be more violent shocks succeeding it.

It was plain enough that their escape, if it was to be made at all, must be made quickly. Jack and Tom at once set about dismantling the wireless station and packing the apparatus.

The hastily extemporized life jacket balloons were hauled down and the wires coiled. When this had been done. Jack told everybody to take their seats in the car, on the top of which the dismantled gas bag had been folded by the captain and the two sailors, while Abner Jennings helped Jupe to pack up.

Jack took his seat last of all and started the engine going. It worked without a hitch, and the auto,—a flying machine no longer,—moved off across the sand, heavily laden as it was, without difficulty.

The rim about the submerged centre of the island was soon circumnavigated, and the beginning of the narrow neck of land reached. Then Jack fairly “let the car out.”

The newly formed isthmus was hard, and the car flew over it under the full power of its engines.

“Mighty good t’ing dere ain’t no speed laws in dis part ob de world,” grunted Jupe as they flew along.

The shore appeared to rush toward them, but if they had hoped to see any signs of human habitation as they drew close to it they were mistaken. Nothing but a mass of trees, backed by rising ground, appeared along the coast as far as the eye could reach in either direction.

As they sped along they heard behind them a sudden mighty uproar. Gazing back they saw the ocean heaving and boiling all about the island they had left, as if it had been a witches’ caldron. Great jets of water shot up, and the surface of the sea was flecked with foam and spume.

The sight fascinated every one of them but Jack, who had to be intent on his driving.

“The whole island is going!” shouted the Professor.

He was right.

With a sudden booming roar and upheaval of the ocean, the entire mass of land sank under the waves, which for a long time boiled and simmered above it. Just as the last vestige of the island vanished, leaving only the newly created peninsula projecting from the land, they reached the solid earth.

Their dash to the mainland had taken place only just in time. A little more delay, they realized with shudders, would have meant their total annihilation.

“I said the island would go,” cried Abner Jennings triumphantly. “I’ve ’em vanish like that in the South Seas.”

No one had any comment to make. The horror of what they had just witnessed struck them all dumb. The gratitude they felt to Divine Providence for their lucky rescue filled their hearts to overflowing, and left no room for speech.

The Flying Road Racer was stopped, and they silently gazed for a long time at the bubbling, heaving waters.

The sight was impressive, even if it did cause a shiver and inspire a feeling that bordered on fear.

After a while the Professor spoke. His tone was as solemn as his words.

“Boys,” he said, addressing his young friends, “we have just witnessed something that many scientists would give a great deal to behold.”

“Well, candidly,” said Tom, “I’ve seen enough of it.”

So had they all, in fact, and the Flying Road Racer was soon turned north, following a rough road that ran parallel with the sea-coast.

It was now late afternoon, and the shadows were lengthening apace. Before long the swift tropic night would overtake them. Although they had arrived at a determination to continue traveling north till they arrived at a large city, where a telegraph wire could be found, they did not care to risk advancing over the rough, half-formed road in the darkness, so a halt was made where a small stream of fresh water ran down to the sea, and they prepared to spend the night there.

It was somewhat chilly and a roaring fire was built around which they seated themselves after the evening meal. All were rather silent and abstracted, and there was no inclination for conversation. The Professor had brought out the silver casket and was examining some queer marks like hieroglyphics on its cover.

“I’m sure they have some sort of meaning,” he remarked to Mr. Jesson, “but it’s beyond me to make out what it can be. See if you can do any better.”

He handed the box to his brother-in-law to examine. But in the transfer it was fumbled, and before Mr. Jesson could save it the silver casket rolled toward the fire, only stopping when it was embedded in a mass of embers.

It was raked out with a stick by Mr. Jesson before it was damaged. He set it aside to cool before examining it, and in the meantime the boys took occasion to observe it more narrowly than they had yet found opportunity to do.

“Say, I thought that those knobs on the top were dull-colored!” exclaimed Jack Chadwick suddenly.

“Why, so they are!” rejoined Mr. Jesson. “Some sort of inferior stone, I guess. They——”

“But they are not dull! Look!”

Risking burning his fingers. Jack seized the still warm casket and held it toward his elders.

On the cover, embedded in the silver, flashed and winked in the firelight, three magnificent gems, red, blue, green!

“Let me look at that a minute. Jack,” exclaimed Professor Chadwick in sharp, excited tones.

He took the box from his son, and an instant later his head and Mr. Jesson’s were close together over the rifled silver casket.

“Well, gentlemen?” said Ned after a while.

“Well,” echoed Professor Chadwick, “we have made a most astounding discovery. These gems which Jack discovered,—for they are genuine, there’s not a doubt of it,—must have been covered with wax of some sort. The heat of the fire, when the box fell into it, melted this substance, and—well, here are three gems worth, conservatively, two hundred and fifty thousand dollars; probably a great deal more.”

The listeners looked at him in amazement.

“But what were the gems that Herrera took out of the casket, then?” demanded Jack, when he found his voice.

“Imitations, undoubtedly,” was the reply of Mr. Jesson. “The tribe that owned the genuine stones adopted this cunning means of concealing the real ones by coating them with wax of some sort. Then they placed inferior gems, or cunning imitations, within the box, trusting to the cupidity of any one who stole them not to investigate further.”

And so it proved afterward. The stones, which the strange and seemingly trivial accident had revealed, turned out to be as fine specimens of their respective kinds as there are in existence. They were appraised at six hundred and eighty thousand dollars, but cryptic carvings on the back of them made them of infinitely more value to science as specimens of the treasures of a vanished race.

Despite their keen excitement over the discovery that, after all, Herrera had not decamped with the precious stones, the adventurers slept soundly and peacefully that night.

When they awakened the daylight was sparkling on land and sea, and Jupe was filling the air with appetizing aromas proceeding from his cooking fire.

It was while they were in the midst of the morning meal that Jack sprang to his feet with a shout.

“The Sea King! the Sea King!” he cried, pointing seaward.

About half a mile off shore, steaming leisurely along, was a fine-looking white yacht that the Professor speedily pronounced to be, indeed, the Sea King.

“The wireless, Tom, as quick as you can,” called Jack, and the two lads at once set about sending their life-jacket balloons aloft.

This time the message that Jack sent out reached the persons it was intended for, and an hour later a boat came ashore and the castaways found themselves among their friends.

Repairs had been effected in record time on the yacht, and those in charge of her had determined not to wait longer at Lone Island, but proceed south at once. They were urged to this course, also, by news from Mexico that the revolutionists had triumphed, and that Diaz had abdicated.

We should like to chronicle more of the adventures of the Boy Inventors on this trip, but the exigencies of space forbid it. Suffice it to say then, that while the Professor, the rescued explorer and the rest, including Captain Andrews, voyaged to Lone Island and thence home on the Sea King, the boys drove the Flying Road Racer through Mexico, and reached home in that way by the overland route. They had many exciting times, but none so filled with peril and incident as their career on the gulf had been.

In due time the Vagrant was also recovered and sent home by the newly formed Madero government. Of Herrera, all trace was lost for a time. But ultimately he was heard from in Paris, whither, as had been prophesied, he had fled when the Diaz government fell. But he is not leading the life of a luxurious refugee there. Far from it. The gems he had stolen with the exercise of so much villainy and planning, proved to be, as Professor Chadwick had conjectured, mere cheap imitations worth very little except as specimens of Maya workmanship. Herrera, when last heard from, was acting as a head waiter in an humble Mexican restaurant in the Latin quarter of the French capital.

The genuine gems were sold to a New York millionaire, and when he dies will be seen in his private museum, which will then be opened to the public. The proceeds were shared, by the wishes of Professor Chadwick and Mr. Jesson, with the faithful crew of the Sea King, each, from Captain Andrews down, receiving a due portion. A handsome monument was also erected above the grave of poor Kettle, who fell in the battle with the Mayas.

Professor Chadwick did not fulfill the object of his cruise in finding a new form of biologic life; but he often says that he established something far more precious,—namely, the safety of his long-lost brother-in-law, Tom Jesson’s father.

One morning, not long after the household at High Towers had settled down to its ordinary routine, a telegram came for Jack. It contained astonishing things, things which were—though he didn’t guess it at the time,—to open up an entirely new field of invention for him and his chums, Tom Jesson and Ned Bangs.

The message stated,—but positively, we must keep all that for another telling. In our next volume we will relate further astonishing and stirring occurrences in the lives of our ingenious, progressive young friends. The title of the forthcoming book will be The Boy Inventors and the Vanishing Gun,—a tale which promises to be of extraordinary interest to every American boy, brimful and running over, as it will be, with experiment and achievement along new and significant lines.