CHAPTER I. THE CAPTAIN’S STORY.
“Stranger than the tales of the Arabian Nights—indeed, almost Munchausen-like in its seemingly improbable character is the tale I am about to give you in truth,” said Captain Nicodemus Beere as he hitched up his trowsers and shifted his quid.

Frank Reade, Jr., drew a deep, quick breath and looked keenly at his visitor.

“That is a sweeping statement,” he declared; “but you are a truthful man, Captain Beere, and of course you mean what you say.”

“I certainly do,” said the doughty captain in his most positive manner. “What is more, I stand ready to furnish undisputed proof of it.”

The captain cleared his throat and began his story. But before we follow him through its thread let us take a closer look at him.

It could be seen at a glance that he was a man much out of the ordinary.

In figure he was stout and well built, with fair features and a heavy, full beard. His blue eyes twinkled with honesty but a certain irascibility of temper peculiar to sea-faring men.

For many years he had sailed the seas and weathered many a hard voyage in all quarters of the world. But two years previous he had retired with the purpose of spending the rest of his days in ease and comfort on shore.

He had been a warm friend of Frank Reade, Sr., long since passed away, and when he heard of the success of Frank Reade, Jr., the son of the famous inventor, he conceived the notion of paying him a visit.

Frank Reade, Jr., received him hospitably in his beautiful Readestown home.

“My father’s friends are mine,” he declared. “I have often heard him speak of you, Captain Beere.”

The captain visited the great machine shops of Frank Reade, Jr., and inspected his various inventions. Among them the one which claimed his deepest interest was the new air-ship, the Spectre.

And as he studied and admired it an idea came into his brain. He at once was determined to broach it to the young inventor.

This idea was to be embodied in the tale which he now proposed to give Frank, and with this explanation let us follow him.

“Ten years ago,” declared the captain, “I was master of as fine a ship as ever rounded Cape Horn. We were south of Panama and somewhere off the coast of Peru when a storm struck us.

“For four days and nights it roared and howled and bellowed. We were buffeted and driven hither and thither, half the time running before the wind. We could not tell where we were nor what would be the end of it all. It seemed as if we must go to the bottom.

“On the fourth day the climax came. The foremast went by the board and carried the maintop with it. Later the main also went and we were almost dismasted. Moreover, the ship began to make water at a fearful rate.

“However, by working sharp we kept her afloat until the morning of the fifth day, which broke clear and bright. On our weather bow we saw land.

“There was no hope of saving the ship, so we worked her down under a jury rig until we found a good place to beach her. Then we went ashore in a long-boat.

“It was a rough, wild coast, with terrible high cliffs and reaches of sand. Of course we climbed the highest cliff to see what was about us.

“Westward was the sea. North and south the rough shore, but eastward was a mountainous country with fearful mountain passes and gorges. There was something weird and mystic about the whole region. But we knew that it was death from starvation to stay by the shore, so we kept on looking for signs of human settlement.

“Before we knew it we were deep in the heart of the strangest region any of us had ever seen. Every cliff or precipice seemed to have the shape of a fiend or a hobgoblin or an elf. The trees were fantastic in shape, there were hideous plants and snake-like vines. At times we came to sluggish streams and deep pools with strange, black depths, apparently bottomless.

“The animals were of an unknown species. There were birds of a talking species, yet unlike parrots. I cannot half describe to you the wonders of this mysterious country.

“For months we wandered through it. Then we came upon the ruins of a city and all the signs of a former civilization. We also discovered that the mountains were haunted by a race of giants, wild barbarians, out of whose way we took care to keep.

“After a time we came to a mighty inland sea or lake, the farther shore of which was so far distant that we could not see it. By the shores of this we sojourned many days.

“But one morning we arose to view a strange state of affairs. Where a few hours before there had existed a mighty lake, we saw now naught but a deep, rocky and sandy basin.

“The water had disappeared and hills and valleys lay in its place. It was a mighty surprise to us. All sorts of theories were advanced.

“That some subterranean channel had opened and carried the water away looked logical. Or perhaps a chasm or barrier at some far end had given way, and the mighty volume had been diverted into another and lower basin.

“Any or all of these theories looked plausible enough, and were accepted without further question. We spent a number of days exploring the basin. By some strange instinct we returned each night from the basin to our camp. To this we owed our lives.

“One day while wandering about the basin, one of our party came upon a curious object.

“It was a structure of rocks closely fitted together with cement. It was half imbedded in a plain of sand. That it was the work of human hands there could be no doubt.

“Of course we were all interested, for it showed that at some time other human beings than ourselves had visited the spot. We at once began to curiously examine the structure.

“This resulted in a thrilling discovery. It was undoubtedly hollow and our first mate, Bill Langley, discovered a movable stone at its summit. He displaced this, and a great cavity was revealed.

“Our first thought, of course, was that it was a tomb or burial place of some extinct race. In looking into the place we would not have been surprised to have come across a heap of old bones or other such evidence.

“But what we did see was far different. Bill leaned over the aperture a while and rubbed his eyes repeatedly. Then he slid down, and said:

“’By jingo, mates! I’m a gallivantin’ old shark, if there ain’t a heap of gold in that ere place!’

“’Gold!’ I exclaimed.

“’With submission, sir!’

“’You are dreaming, man!’ I exclaimed somewhat excited. ’Do you mean it?’

“’Every word, skipper,’ replied Bill, solemnly. And I saw that he meant just what he said.

“This was enough for me. So I climbed upon the mound and looked in also. Something bright and yellow struck my gaze. I gave a gasp and then I cried:

“’Give me a rope, mates. Steady me while I go down there!’

“And with a rope around my waist I slid down into the mound. It did not require but a few moments to satisfy me that we had discovered buried treasure.

“Yes, sir, gold! Yellow, glittering stuff, enough to make us all millionaires. I own that I was near crazy at the time. There it lay in bars and ingots. All that was left was to take it away to civilization.

“I crawled out of the mound and then we all sat down and discussed the matter. There were fifteen of us.

“Bill Langley proposed a fair division. Of course this was satisfactory. Then it was decided to take the gold out of the mound.

“The gold fever was upon us; we worked like badgers at it. In a few hours we had a heap of the stuff piled up beside the mound. Then nightfall began to threaten. We suspended work, and it was decided not to return to camp, but remain on the spot until morning. There was not the remotest chance of anybody’s purloining the gold, yet all wanted to stay there.

“However, much of our necessary utensils were at the old camp. It was about three miles distant. At length Bill Langley and I decided to return for them and come back in the morning.

“So we set out for the old camp, and reached there an hour later, much fatigued. We lit a fire and sat down by it; but we could not sleep.

“All we could do was to talk about the treasure and what golden plans we could lay for the future. Midnight came and passed.

“Then I began to feel a bit drowsy, and suggested turning in; but the words hadn’t left my lips when Bill gave a quick start.

“’Great gunnels, mate!’ he exclaimed; ’what in the Old Harry was that?’

“The same sound came to my ears. It was a distant, monotonous boom like rolling thunder. The ground actually shook under our feet.

“Only once had I heard a similar frightful sound, and that was once during an earthquake in Panama. But was this an earthquake?

“We sprang to our feet. Bill picked up a fire brand and held it high. But we could see nothing but a few faint stars overhead. It was the blackest kind of a night.

“For a space of thirty minutes the same dull roaring and trembling continued. Then came a dead silence.

“We had about given up interest in the matter, thinking it some inexplicable phenomenon of a tropical clime, when a sudden, startling thing happened.

“A terrific boom, and a swirling, rushing mass came whooping down through the lake basin. The next moment we were picked up as if in giant arms and carried clean to the summit of the eminence beyond us, and there we clung to palm trees, wet as drowned rats.”
CHAPTER II. FRANK MAKES A DECISION.
The captain shifted his quid again and then smiled at the earnest look in Frank’s eyes. The young inventor was intensely interested.

“How did we get wet?” interrogated the captain. “Water of course. It was all before us. It had come down upon us with the force of a hurricane.

“We waited where we were until the light of day came. Then we beheld an appalling scene. A mighty expanse of water lay before us.

“The lake had come back. The basin was full of water. Evidently it had a trick of doing this. That it was of the transient kind there was no doubt.

“I won’t attempt any theorizing or explanation of the phenomenon. I describe it to you just as it occurred. That is all. You’ll have to guess the rest.

“What of our shipmates and the gold? I don’t know. We never saw them again. We could do nothing but push on to the northward. For months we wandered until we came to a great river leading down to the Paraguay. Thence we made our way to Parana and shipped home. This is my story.”

Frank drew a deep breath.

For a moment after the captain had finished he could not speak. At length he managed to say:

“You think the gold is still at the bottom of that lake?”

“Yes.”

“And that the lake is transient, or has spells of changing its basin?”

“Just so, mate!”

Frank was thoughtful for a moment. Finally he said:

“Do you think it would be easy to find that locality again?”

“Oh, there’s the rub,” said Beere, rubbing his hands; “in my lifetime I have made six attempts and failed. But, of course, we traveled overland.”

The same thought came to each.

“Then you think the air-ship—on account of a better view of the earth, could locate it?”

“I do,” replied Nicodemus. “Now you have the whole thing in a nutshell, Frank. The moment I looked at your air-ship, I saw a possible way to visit the mysterious country and locate the Transient Lake.”

Frank Reade, Jr., seemed for a moment in a glow. His eyes shone like blazing stars, and his manner was all eagerness.

“By Jove, you have done it, Captain Nicodemus!” he declared. “I have been trying to decide upon a new trip with the Spectre, and to visit the Transient Lake is just the thing. It promises eager anticipation, excitement and thrilling adventure.”

The captain leaned over the table.

“You will go?” he asked, tensely.

“Yes,” replied Frank.

“And—will you allow me to go with you?”

“I would not think of going without you!” declared Frank.

“Thank you! I had quit the sea, and never thought to take another voyage. But a cruise in the air—that’s different, mate. When shall I report?”

“We will start within a week,” declared Frank; “it will not take long to get things in readiness. I will have Barney and Pomp put stores on board at once.”

We will not dwell upon the further conversation which followed. Suffice it to say that before the old captain left Readestown all arrangements were made.

Barney O’Shea was a jolly Irish boy, who had been long in the employ of Frank Reade, Jr. Pomp was a negro valet who was as devoted to Frank as man could be.

Wherever Frank traveled these two faithful chaps accompanied him.

Frank’s first move after the departure of Captain Nicodemus was to ring a bell. Instantly it was answered by Barney.

The Celt stood in the doorway and ducked his red head in response to Frank’s call.

“Shure, here I am, sor!” he declared.

“Where is Pomp?” asked Frank.

The Celt gave a queer little whistle. Almost instantly a comical little darky appeared beside him.

“Here I is, sah!” he said, with a scrape and a grin.

“Well, you jolly rascals,” said Frank, with a laugh. “I have some good news for you.”

“Golly, Marse Frank, wha’ am it?”

“Bejabers, it’s glad we are to hear that, sor!”

“Well,” said Frank, quickly, “I want you to have the Spectre ready for a quick departure. We are bound for a cruise to South America.”

Barney threw a handspring, and Pomp cut a pigeon-wing.

“Hi, hi!” cried the darky; “dat am jes’ too good news fo’ anyfing!”

“Be me sowl, I’m deloighted!”

“Put provisions aboard the Spectre at once,” ordered Frank. “See that she is completely equipped for a long cruise. You know what to do.”

Away scampered the two jolly fellows. So high were their spirits that they bubbled over, and before the yard of the machine works was crossed they fell to wrestling with each other.

“Hi, hi, chile!” sputtered Pomp, getting a grapevine on the Celt; “I kin trow yo’ jes’ as easy as yo’ like. Look out dar fo’ squalls!”

“Not much, me friend,” retorted Barney, securing an elbow lock. “One—two—three—an’ over yez go!”

They rolled around the yard for somewhile like a couple of monkeys. Neither desisted until they were completely exhausted; then each sped away to do Frank’s bidding.

“I git square wif yo’ yet, yo’ no ’count I’ishman,” cried Pomp.

“Yez aren’t the soize,” retorted Barney.

In the great, high-roofed storehouse the Spectre rested upon her stocks.

She was a marvel of beauty and symmetry. Her lines were somewhat like those of a government cruiser, yet more narrow of beam and slender.

The hull was of thinly rolled composition of aluminum and steel to insure lightness and make it impervious to a bullet. The hull was pierced just below the rail with a number of dead-eye windows, which admitted light to the hold.

Above the deck there arose two cabins. The forward cabin was richly furnished, and contained the dining saloon and the living quarters of the ship’s company.

The after cabin contained the staterooms and berths. It was provided with dead-eye windows, and could be made airtight in the event of the air-ship ascending into the rarefied atmosphere above the clouds, where human life could not be supported.

Forward was the pilot-house, a dome-shaped structure with heavy plate glass windows. In this were the steering gear and electric keyboard, with all nautical and scientific instruments suitable for navigation in the air.

The propelling power of the air-ship was furnished by electric motors placed in the hold. These drove a huge fan propeller at the stern.

Also they drove the four powerful helices placed upon revolving masts above the deck. These furnished the lifting power of the air-ship, which was most tremendous.

Everything about the Spectre was ship-shape and elegant, from the polished brass-work to the silver-bladed helices and shiny steel masts. It was a marvel of beauty and grace and appointment.

Having said this much we will close this brief and incomplete description of the great air-ship, leaving the reader to gather a more correct impression from the accurate representation of the artist.

A few evenings thereafter Frank received the following telegram from Captain Nicodemus:

“Dear Frank—Am all ready for the start. Shall I come to Readestown or will you stop for me at New Orleans, where I am at present? Wire me.
“Yours, ? ? ? Nicodemus Beere.”

Frank at once answered that he would pick the captain up at New Orleans on the way to the Gulf. Then he hastened preparations for the start.

It was not long before the air-ship was rolled out into the great yard and was all ready for the start.

Then the people of Readestown rose en masse to give their distinguished fellow-citizen an ovation and a grand farewell to speed him on his journey.

The fame of the undertaking had traveled far and wide and from every part of the country people flocked to Readestown.

Their curiosity was most powerful to see the man who had mastered so easily the great problem of aerial navigation.

Frank was obliged to decline all invitations to events given in his honor. His full time was occupied in preparations for the start.

And at last all was ready.

Frank wired Beere at New Orleans and then went aboard the air-ship. Barney and Pomp accompanied him.

It was a beautiful August morning. A mighty crowd thronged the streets of Readestown to get a look at the air-ship as it mounted in the air.

None of them were disappointed.

Exactly at the hour named the Spectre leaped upward into the clouds. The people cheered and the bands played and cannon roared. And away sailed the Spectre.

Into space she sped, every moment growing smaller, until soon she was lost to sight altogether.

The great journey was begun.

The voyagers were destined to meet with many thrilling adventures ere they should see home again. What these were it will be our duty to chronicle.

“Begorra, she sails foine!” said Barney with delight, as he trimmed the course of the air-ship a bit; “she’ll niver be beat, Misther Frank!”

“I think myself that she sails well,” said the critical young inventor. “I shall not try to beat her this year.”

“Golly, Marse Frank, yo’ don’t hab no need ter,” declared Pomp; “she am good fo’ a long voyage, sah!”

“Begorra, phwere is it we will be afther meetin’ the other man?” asked Barney.

“At New Orleans,” replied Frank.

“An’ how far is that, sor?”

“About a thousand miles. We will make it in two days easy enough.”

“It is on our course, sor?”

“Yes.”

The air-ship sailed on over a mighty panorama of mountain and valley, hill and plain, lake and forest and river. Great cities alternated with little towns. It was a mighty spectacle from the air-ship’s deck.
CHAPTER III. IN THE ANDES.
“Be me sowl, it’s a big country Ameriky is!” declared Barney, as he glanced over the rail. “Shure, it’ll take a heap av foightin’ to iver conquer her!”

“The days of national conquest are over, I guess,” said Frank. “At least I hope so. That is a custom relegated to the dark ages.”

“Hard luck fer ould Oireland,” declared the Celt; “shure av it was to-day she was free, England wud niver conquer her thin.”

“Golly! yo’ might borrow dis air-ship from Marse Frank an’ set yo’ island free if yo’ wanted to,” declared Pomp; “shuah, yo’ cud blow up de hull lot ob dem Britishers.”

Barney’s eyes blazed.

“Bejabers, it’s no more thin they desarve, bad cess to thim,” he declared. “Shure, they’ve had their feet on sufferin’ Oireland’s neck long enuff.”

And so Barney continued to dilate upon the wrongs, real and fancied, of his native isle. He kept on until Pomp began to guy him.

Then he got angry.

“Huh!” cried the darky, “if yo’ people was set free dey nebber cud govern demselves! Shuah dey wud be eatin’ each other up fo’ a fac’!”

“Phwat’s that yez say?” blustered Barney, angrily; “don’t yez cast no aspersions on the ould sod, yez black pickaninny! Shure yez own people wud niver have got free av it hadn’t been fer Gineral Lincoln!”

“Dat shows all yo’ know ’bout fings,” sniffed Pomp; “dar warn’t no sich man as Gineral Linkum.”

“Hey! phwat’s that, naygur? Don’t yez give me de lie!”

“Huh! Linkum warn’t no gineral, sah! He was de President, I’d hab yo’ know, sah!”

Barney elevated his nose contemptuously.

“Be me sowl it’s mighty little yez know onyway. An’ ain’t the President commander-in-chief av the army an’ navy? An’ don’t that make him the bigges’ gineral in the land?”

Pomp saw the point and wilted. He slunk into the galley, muttering:

“I jes’ fix dat I’ishman fo’ pretendin’ to know so much. I jes’ hab a dose ready fo’ him yet!”

What this was we must wait for a later hour to decide. For the present we will consider nearer incidents.

In due course New Orleans was sighted. The air-ship hung over the southern city.

Frank looked for a certain signal, which he saw finally upon the roof of one of the houses.

It was a yellow flag.

At once the air-ship bore down upon it and soon descended within fifty feet of the roof. Up through a skylight popped Captain Nicodemus.

“Ahoy the ship!” he cried.

“Ahoy!” replied Frank.

“I am ready to come aboard. Throw out your gangway!”

“Is that roof strong enough to bear the weight of the air-ship?” asked Frank.

“Surely, mate! Come down.”

“All right!”

Frank let the air-ship descend and rest upon the roof of the building. Then he sprang down and shook hands with the captain.

Nicodemus was delighted.

He was all equipped for the trip.

But his personal appearance was startling as well as amusing in the extreme.

The old captain had got himself up in the style of the privateer captain of forty or fifty years previous. He wore fancy high boots, clinging cutlass, pistols in belt, a velvet blouse and pea-jacket.

He looked as if equipped for a privateering or piratical cruise, and Frank could not help a smile.

“You look as if you expected trouble,” he exclaimed. “Why have you armed yourself?”

“Hang me high!” cried the captain, fiercely; “are we not going into a land full of sharks and cuttlefish? Keep your eye on your outfit, lad. We will need a little powder and ball and cold steel before we get home.”

“Well,” said Frank, “you may be right; but I never employ arms until the necessary time comes. You are taking time by the forelock.”

“Which is correct, skipper. I once knew a fair ship to become overrun with pirates out in the Maldives, just because the skipper would not carry powder for fear of blowing up the ship. He had an aversion to the smell.”

Frank could not but laugh.

“Well,” he agreed, “you may be right. However, this air-ship is an adjunct of Liberty Hall, so that you are all right. Keep your eye out for sharks.”

“Depend on it, skipper. But will we wait long at this port?”

“Not another moment,” declared Frank; “let us be off at once.”

He made a motion to Barney and the air-ship left the roof. As it soared aloft, the streets below were seen to be crowded with curious people craning their necks.

Soon the Spectre was sailing over the jetties and the delta of the Mississippi, and beyond were seen the waters of the Gulf.

Captain Nicodemus walked the deck of the air-ship, completely in his element.

He sniffed the air and leveled his long glass at the distant horizon.

“This beats ocean navigation all to pieces,” he declared. “There’s nothing like an air-ship.”

“Then you like it better than the sea?” asked Frank.

“Why not, skipper? In the first place, you can sail faster. You are surer of making port on time. There’s no sails to furl or set. It’s handsome sailing, and no care for the wind.”

Frank saw the old captain’s logic, and was inclined to agree with him.

“You are right, captain,” he said. “Aerial navigation beats all else. But looking into the future, what shall we make a bee line for when we get across this gulf?”

“For the Andes of Peru, then follow on down their eastern slope. I think by so doing we shall come to the mysterious country.”

“Very good. But how will you identify the Transient Lake if the water is all out of it?”

“Trust me for that, skipper, I could never fail to locate it. I hope the water is out of it?”

“Why?”

“We could then easily follow the basin’s course and find the gold.”

“I can see. Well, keep a sharp outlook when we reach the Andes. I shall strike across the Caribbean Sea for the mountains of Peru.”

“Good! I feel sure of success!”

The air-ship swept on southward. In due time the coast of Cuba hove into view.

Upon its western end was Cape San Antonio. Frank passed directly over this and entered upon the Caribbean Sea.

It was evident now that they were well into the tropics. The air was balmy and the sea limpid and still.

When the coast of Colombia came into view the exciting period seemed to have been reached. Beyond all knew that the land of wild adventure lay.

On sailed the Spectre.

Over the coast it passed and into the interior of Colombia. The scenery was grand, and of the typical sort peculiar to South America.

And still the Spectre kept on until great dreamy-looking peaks rose from the western horizon.

“The Andes!”

All crowded to the rail, and with thrilling veins regarded the range of wonderful mountains, in fact, the most wonderful in the world.

The Andes of Peru upon the eastern slope are peculiarly rough and picturesque.

It was in these mighty fastnesses that the ancient Incas had built their temples and held their own in battle with the lawless Spaniard, until their wealth, their glory and their prestige was forever lost to them.

Mighty Sarata with its altitude of 21,286 feet, gigantic Illimani with its 21,000 feet, the great volcano of Guallatieri with 22,000 feet, Titicaca, Vilcanata, Misti and all the monarchs of that awful aggregation of peaks, than which the world has no superior, were all about the air-ship.

Gliding from one fleecy cloud to another, the jagged heights in their solemn grandeur were visible only at intervals. Captain Beere could hardly contain himself.

“By the horn spoon!” he cried. “When you can find anything to equal this, I’ll like to know where it can be. Is it not powerful, mates?”

“Indeed it is!” replied Frank.

All of the voyagers wore a face mask, an invention of Frank Reade, Jr.’s, for use in high altitudes to prevent bleeding of the respiratory organs or faintness. It was impregnated with a chemical, which, placed in a light porous sponge at the nostrils, was a sure remedy.

So that they were enabled to travel with impunity in that high atmosphere.

“I have heard great reports of the malady encountered in the high Andes, known as the mountain sickness,” said Nicodemus; “it don’t seem to trouble us as yet, Frank.”

“That is easily understood,” said the young inventor; “we are in the air, and consequently do not feel the pressure as we would if we stood on the mountain summit or terra firma. The buoyancy of the air-ship overcomes that peculiar pressure which causes the so-called mountain sickness.”

The air-ship sailed on slowly among the great peaks. It was a wonderful spectacle.

But the aerial voyagers soon tired of it, and Frank finally asked:

“What do you think, Nicodemus? Is the mysterious country south of us?”

“I think so, skipper,” replied the captain. “We kept a pretty straight line eastward to the head waters of the Paraguay River; we ought to find the Transient Lake somewhere south of us.”

“We will keep on then in that direction,” said Frank. “Heigho! What is that?”

The air-ship gave a sudden mad plunge forward. There was a terrific explosion in the distance like the boom of a hundred great guns.

It was the wave of air coming from that direction which had given the motion to the Spectre. But this was not all.

From a cloud just above the air-ship blazing balls of fire suddenly shot downward.

A tremendous crash ensued on the air-ship’s deck, and she reeled and shot downward.
CHAPTER IV. THE FIGHT WITH THE PUMA.
The air-ship was falling.

For a moment horror was upon all in the little party. It was a terrible realization, for below, thousands of feet, they might be dashed to atoms upon jagged ledges.

A powerful missile had fallen from the cloud and struck full and fair in the air-ship’s bow. The shock had thrown open the pilot-house door.

The helices had ceased to revolve but slowly and the air-ship was floating downward with speed. For one awful second the aerial voyagers knew not what move to make.

Then Frank Reade, Jr., acted.

Quick as a flash he sprang into the pilot-house. Barney, who was at the wheel, had been knocked half senseless to the deck.

One glance told Frank the truth. The shock of the falling missile had caused the helix lever to fly shut and had shut off the electric current. This had checked the speed of the helices and allowed the air-ship to fall.

With one leap Frank reached the keyboard.

He turned the lever swiftly and to his horror found that it was bent. However, the downward speed of the ship was materially checked.

The next moment there was a shock and she rested upon the ground. Then Frank shut off the current entirely.

He sprang out of the pilot-house and glanced about to see that they were resting safely upon a broad expanse of ledge on the mountain side.

Below them sloped the mountain for miles into green valleys. The danger was over.

“Be me sowl!” gasped Barney, as he crawled to his feet; “phwat the divil was it that was afther hitting me? Shure it med me dizzy the while.”

“Hang me high!” roared Nicodemus, “I thought our bones were spoiled for that! How did we escape?”

“It was a close call,” said Frank.

“Golly! Wha’ was dat struck us?” interrogated Pomp.

“We’ll find out!” said Frank, as he advanced to the bow.

And there the cause of the mischief was found. This was in the shape of a huge fragment of volcanic rock which had cut its way half through the deck plates, and was so firmly imbedded that it required great strength to dislodge it.

This was only one of the score or more aerolites which had fallen from the sky.

That they might have been hurled aloft from the distant volcano there was a strong likelihood. That no worse damage was done was fortunate.

The air-ship rested safely enough upon the ledge of rock. Frank proceeded at once to repair the injury.

While he was working at the keyboard, Nicodemus and Barney bethought themselves that it was a good opportunity for an exploring tour over the ledges.

So they took their rifles and climbed over the rail. They had descended to an altitude now where the air was not so rare, or there was little danger of the deadly mountain sickness.

They had spied some mountain goats and the captain was anxious to get a shot at them.

So they proceeded some distance down the mountain side until the air-ship was lost to sight. The view at this point was very grand.

Far below there were great slopes of green, alternating with shelving rock. In the vista beyond a mighty green valley extended to the base of other mountains seventy or eighty miles away.

Such scenery could hardly be eclipsed anywhere else in the world. The two men could not help but gaze upon it with wonderment.

“Be me sowl,” averred Barney, “it’s a long way down there.”

“That is true,” agreed Nicodemus. “I wouldn’t care to walk it. But—hello! what is that?”

The captain came to a sudden halt, and raised his gun with one finger ready on the trigger.

There was good cause for this. Along the mountain wall there was creeping toward them a huge black form flattened against the ledges.

It required but a glance for the captain to recognize the deadly foe of the South American traveler, the puma, or mountain lion.

The creature was bent upon attacking them, as could be readily seen. It was a moment of peril.

“Separate!” said the captain sharply, moving to the right. “Keep your eyes open, Barney!”

“All roight, sor!”

This movement seemed for a moment to disconcert the puma. It seemed in a quandary as to what direction to take.

Finally it moved toward Barney. The Celt got behind a bowlder.

He held his rifle ready for use, and his shock of red hair stood literally on end.

“Be me sowl!” he muttered, “av the vilyun gets his clutches on me, shure it’s lost I am! I’m afther thinkin’ I’ll niver give him that chance.”

Captain Nicodemus, meanwhile, had been getting a line on the beast.

“Steady, Barney!” he cried. “I’ll give him a shot. If he turns for me you give him another!”

“All roight, sor!”

Nicodemus drew straight and careful aim. Then he pulled the trigger.

Crack!

Where the bullet struck the puma it was not easy to say. But the animal gave a quick snarling cry and wheeled about.

He raised himself a trifle from the ground. It was Barney’s chance.

“Bad cess to ye!” he muttered, and drew quick aim.

Crack!

Another bullet struck the puma. But the animal had already made its spring. Straight for the covert of its human foe it shot.

Captain Nicodemus saw that his life hung in the balance. He did not shirk the responsibility.

It was a momentous occasion.

He raised himself and took cool and steady aim. If his bullet hit the mark he would stop the beast. If not—then the worst might happen.

It was a moment of brief suspense. All his nerves were on the qui vive. Then he fired.

Crack-ack!

Two reports blended in one, for Barney fired at the same moment. One moment the puma was in mid-air, then fell, turning a dozen somersaults.

When it ceased its terrific death struggle the two hunters ventured to approach it. A more ferocious beast could not be imagined.

“Egad!” exclaimed Nicodemus, as he placed fresh cartridges in his rifle, “the beast gave us quite a tussle. We’re in high luck!”

“Begorra, I believe yez, sor!” agreed Barney. “I niver was more skeered in me loife. One moment I thought it was me the omadhoun was after, then I thought it was yesilf.”

The captain laughed and kicked the body of the dead lion.

“I’ve half a mind to take his skin!” he said, “but I don’t believe it would pay. On my word, I think I see a mountain antelope yonder. Let us try for him!”

Both hunters started to creep up the mountain side. Upon a distant spur of rock, sure enough, there stood a goat.

Nearer they crept. It was necessary to proceed with the greatest caution. These mountain goats were shrewd and exceedingly wary.

But it did not spy its human foes, however, until they were within gunshot. Then both fired.

One or more of the bullets hit the mark, for the goat gave a spring in the air and fell.

It came sliding and rolling down the mountain side, and fell almost at the feet of the hunters. In a moment its carcass was secured.

Nicodemus was well satisfied.

The object of the expedition had been accomplished, and he did not care to go further. The goat was slung over his shoulders, and he proposed to return to the air-ship.

This, however, was speedily discovered to be not such an easy matter. They had wandered far and somehow lost their bearings.

The region had all a peculiar sameness. It was some while before Barney was able to decide the direction from which they had come.

But the points of the compass were finally settled, and they set out upon the return. But though they journeyed on for an hour, no sign of the air-ship was seen.

Finally they were brought to a halt by a deep chasm, with sides too precipitous to descend. Here they were forced to come to a dismayed halt.

“By whales!” exclaimed Nicodemus Beere, “here’s a pretty how d’ye do! Where are we, Barney? Do ye know?”

“Be me sowl, it’s sthuck I am intoirely,” replied the Celt. “Shure, I thought we was going roight all the while.”

“Well, it’s plain that we were not,” replied the captain. “We must make a back course or we’ll be lost.”

“On me wurrud I belave it’s lost we are already,” declared Barney. “Shure, I don’t know phwere I am.”

Captain Nicodemus was in a most uncomfortable frame of mind. He stormed up and down the ledges excitedly.

“This is a fine mess!” he scolded. “What is going to be the result? Darkness is coming on, and we will have to spend the night here. We will stand a chance of being eaten up by wild beasts.”

“Och hone!” gasped Barney, “do yez mean that, sor! It’s bad luck fer us, to be shure.”

Once again they set out along the mountain side.

But again their quest was in vain. Each forgot that they had ascended the mountain some distance in quest of goats and that the air-ship consequently must be just below them.

Nightfall was coming on rapidly. Finally they abandoned all idea of finding the air-ship. It was decided that they must spend the night there.

So they fell hastily to collecting fagots to make a fire.

Soon they had a large pile of them ready to light. They knew that fire would keep wild beasts at bay, and this was their safeguard.

Under the shadow of a huge ledge they made their camp and waited for daylight to come again. There was no sleep for either that night. They could only wait the dawn.

CHAPTER V. THE CAPTAIN’S DISAPPEARANCE.
Meanwhile Frank had finished his repairing in the pilot-house and began to arrange for resuming the journey once more.

He kept a lookout for Barney and the captain.

But for some inexplicable reason they did not seem to show up. Soon twilight came.

“That is queer,” he muttered, “they are making a long trip. It is time that they should return.”

“Dat am a fac’, sah,” averred Pomp; “reckon dat wild I’ishman hab led dem away somewhere.”

Frank fretted and fumed for a long time. Certainly they had ought to be on hand by this time.

Darkness came. Then he made up his mind that something was wrong.

Either something had befallen them or they were lost. He credited the latter assumption.

The air-ship was lit-up by the electric lamps and until a late hour watch was kept. Then Frank went into the pilot-house.

“We have got to go to their rescue,” he said.

“Golly, Marse Frank!” exclaimed Pomp, “how we know whar to look fo’ dem?”

“We must do the best we can,” said Frank. “You stand by the searchlight, Pomp, and shoot its rays everywhere through the mountains. I will manage the wheel.”

Pomp proceeded to obey orders. The air-ship rose, and while Frank sent it along the mountain side Pomp operated the searchlight.

And here was where the two searchers got off the track. As fate had it, Frank took the opposite direction, and, misled by an angle in the mountain, passed directly around to the other side.

Here he followed the mountain wall in all directions. The result was that he kept moving further and further from the spot where Barney and the captain were in hiding from the dreaded wild beasts.

All night long the young inventor kept up the futile quest.

When daylight came he and Pomp were so thoroughly worn out that it was decided to abandon the quest for a few hours of needed rest.

Accordingly the air-ship descended and rested upon a small shelf of rock jutting out from the mountain side. Then Frank cast himself upon his couch and fell asleep.

Pomp remained on guard for a couple of hours. Then he was relieved by Frank. The darky turned in for much needed rest.

Frank could not remain idle.

He sent the air-ship aloft and now saw his error of the night. He had sailed completely around the mountain peak and had been searching the wrong side of it all the while.

“Egad!” he muttered, “it is no wonder that I did not find them. I hope they are yet safe. Remaining out all night on these mountains is no joking matter.”

He hastened to drive the air-ship around to the opposite side of the peak again. As he did so the Spectre hung for a moment over a deep chasm thousands of feet in depth.

Involuntarily Frank glanced down into the chasm, and then gave a great cry of astonishment and alarm.

Far down in these awful depths he witnessed a thrilling scene.

A man hung over the fearful verge by the roots of a clinging vine.

It was knotted about his body, and he swung to and fro over the verge, liable at any moment to be precipitated to an awful death.

It required but a moment for Frank to recognize the unfortunate man. It was Barney O’Shea.

The Celt’s face was deadly pale and streaked with blood. His clothing was torn, and his appearance that of one who had experienced a hard battle.

As he saw the air-ship above him he waved his arm feebly. Frank answered the signal.

Then he allowed the Spectre to sink down into the chasm. It was quickly close by the Celt, and Frank threw a noosed rope over the rail.

“Barney,” he cried, “what does this mean? How came you in this position?”

“Shure, sor, I had a fight with a panther,” replied the Irishman. “We wint over the edge wid so much strugglin’, and I caught by luck in these vines. The crayter is dead at the bottom av this place.”

“You have been preserved by Providence,” declared Frank; “but where is the captain?”

“Shure, sor, yez have the best av me there,” replied Barney. “We siperated about midnight, an’ I’ve niver seen him since.”

In a few moments Barney was drawn aboard the air-ship, and then he told his story.

It was a thrilling one.

It seemed that he had fallen asleep at the little camp-fire under the shelf or rock, where he and the captain had hoped to spend the night safely.

Suddenly he was awakened by a terrific screech, and in trying to gain his feet a monster panther had pounced upon him.

He made a desperate fight with his knife, but the animal dragged him a long ways over the rough ground. Then, as Barney made a fresh battle with the beast, they had rolled over the precipice, with what result we already know.

This was all that the Celt could tell. What had become of the captain he could not say. It was a puzzling matter.

However, Frank proposed that they should return to the spot where the camp had been made and look for some sign of the missing mariner.

It was easy to follow the trail over the rocks which was marked with Barney’s blood.

Then they came upon the camp. It presented only a few burned fagots and a heap of ashes.

Nicodemus was gone. He had left no visible trail.

This was strange enough.

Pomp had now come on deck and assisted Frank and Barney. But not the slightest clew could be found.

There were various hypotheses to be advanced. It was possible that the captain, being suddenly awakened by the appearance of the panther, had taken fright and incontinently fled. That in the darkness he had lost his way and was somewhere in the region aimlessly wandering about.

It was not at all likely that he had been killed, devoured, or dragged away by any wild beast as had Barney, else some trace would have been left behind.

A deeper mystery could hardly be imagined. But there was no time to lose.

The air-ship proceeded to skirt the mountain side, and every cranny and nook was explored.

But yet no sign of the lost captain was found. The day wore on and it began to look as if another night would be passed in the vicinity.

“Shure it’s very quare,” declared Barney. “I don’t see phwat he should go away for at all for whin the baste was afther me instid av himsilf.”

“It was not like the captain,” declared Frank, “he would rather have paused to give you aid.”

“So I should think, sor. It’s moighty quare indade.”

But at the eleventh hour the mystery was solved. The air-ship dropped down the side of the peak a short distance, and this brought into view a long jagged spur of rock which shot out from the mountain wall and hung over an abyss thousands of feet deep.

And upon the very extremity of this there was seen the figure of a man. He waved his arms as the air-ship approached.

“By Jupiter!” exclaimed Frank, “that is Beere. How did he get out there?”

Indeed, this question might well be asked. It was not an easy one to answer.

It seemed almost incredible that a man could climb so far out on that awful pinnacle of rock. And once there, return was clearly impossible.

So it could be seen that the captain’s plight was a fearful one. But the air-ship sailed down upon him.

“Heigho!” shouted Frank. “What are you doing down there, captain?”

“That’s what I’ve been asking myself, mate,” replied the mariner, “give me a lift before I fall.”

“All right!”

Frank lowered the same rope with which he had hauled Barney up.

In a few moments the captain was safe on the air-ship’s deck.

His story was a remarkable one.

“How did I get there?” he exclaimed. “I couldn’t tell ye. I only know that I went to sleep in the little camp with Barney. When I woke up I was hanging on out there.”

“Somnambulism!” suggested Frank.

“I reckon so; I am subject to that. Sure to walk in my sleep if I go to bed with too much on my mind.”

“Whew!” exclaimed Frank. “You are hardly a safe man aboard an air-ship then.”

“I reckon not. But—how did you make out, Barney?”

The captain was astonished when he heard the account of Barney’s adventures. He had seen nothing of the panther, nor had he any recollection of anything until he came out of his sleep to find himself on the projecting spur of rock.

However, the affair was ended, and all were safe again aboard the Spectre, which was a matter for congratulation; so Frank at once proceeded to again direct the course of the air-ship.

Down among the valleys now the air-ship sailed. The country, however, was wild and unsettled, though the scattered villages of a few Indian natives were seen.

“It’s about time for us to get a look at the region about the Transient Lake,” declared Nicodemus.

“Can you see anything familiar about this region?” asked Frank.

“Yes,” replied the old mariner. “Yonder is the range of hills where the Paraguay River rises, if my eyesight does not fail me. On the other side of them we first found human beings.”

“Well,” said Frank reflectively, “we don’t want to go there.”

“No,” replied the captain; “steer west by south. I think that is our best course.”

The words were scarcely spoken when a great cry came from Barney and Pomp, who were aft. Frank and Nicodemus turned to behold an appalling spectacle.
CHAPTER VI. THE ANDEAN STORM.
West of them there was a deep and narrow gorge between high mountains. Down through this with the speed of a race horse there came a tumbling funnel-shaped cloud.

So swift did it come and so unexpected was it, that the voyagers were wholly unprepared and taken by surprise.

But in that swift instant all realized what it meant.

A storm in the Andes is a terrible affair. Darting among the great peaks it sweeps with cyclonic fury through the valleys, carrying destruction in its path until its force is spent.

Such was now swooping down upon the air-ship like a mighty bird of prey.

There was no time to get out of the way to make any change in course. Barney and Pomp sprang into the forward cabin, shutting the door behind them.

Frank and the captain leaped into the pilot-house.

They were not a moment too soon.

The storm struck the air-ship like a thunderbolt. What saved it from being totally destroyed was a literal wonder.

It was utterly impossible for any of the voyagers to recall what transpired in that period while the air-ship was in the clutches of the hurricane.

Frank had turned the lever to send the air-ship above the storm. But he had not done this quickly enough.

The weight of the storm had kept it down. It was whirled about like a top, dashed hither and thither madly.

The voyagers were hurled about the interior like puppets. Nothing could be seen beyond the windows, nor could they even guess where they were being whirled.

How long this lasted they were never able to guess.

Frank gave up all as lost. He had not the slightest faith that the helices and masts would successfully resist the shock.

When the wind ceased for a moment its force, he expected to be dashed to atoms upon the earth below.

But the unexpected often happens.

The storm departed almost as suddenly as it came. The wind died out, the air-ship ceased whirling and the blackness disappeared.

The sun burst forth once more and all was again light.

Barney crawled out from under a heap of wreckage, and Pomp relaxed a grip on the skylight frame.

Frank crept out from under the electric keyboard, and Captain Beere appeared from the wine closet with a fragment of the door in his hand.

“Great whales!” he bellowed; “I’ve sailed the high seas in many a hot typhoon, but I never saw the equal of this one.”

“We seem to be afloat,” said Frank, with an attempt to straighten a crick in his neck.

Then he glanced out of the window and saw that the helices were revolving furiously.

The air-ship was speeding upward and frost was forming on the windows. But Frank quickly checked the helices.

The Spectre sank a mile or two very quickly and continued going down until the gauge recorded an altitude of two thousand feet. Then all went to the windows and gazed out.

The scene spread below was a startling one.

Instead of tropical forests or craggy heights there was visible nothing but a mighty expanse of water.

As far as the eye could reach in all directions this was all that could be seen.

Astounded, the voyagers regarded the scene for a time in silence.

Then Frank cried:

“On my word I believe we have been carried clean over the continent and out to sea.”

“Begorra, it’s the ocean,” averred Barney.

“Golly! we must hab trabeled pretty fast,” declared Pomp.

But Captain Nicodemus studied the scene below critically and then said decidedly:

“It is the big lake again.”

“What!” exclaimed Frank.

“It is the lake we’re looking for,” declared the mariner. “We have made it at last, thanks to the storm.”

Frank was astounded.

“I have never heard of any body of water as large as this in Central South America,” he said.

“Well, I can’t help that,” said the captain logically; “here it is.”

“You say this is the Transient Lake?”

“I do.”

With redoubled interest the aerial voyagers now gazed upon the great body of water below.

None were disposed to dispute the old captain, and Frank, scanning the horizon more intently, saw the faint haze of the shore.

“By Jove!” he exclaimed, “it is a big body of fresh water. However, here we are. Now to recover the treasure. What course shall we pursue, Captain Nicodemus?”

The old captain was much excited.

He walked up and down the deck, rubbing his hands and studying the horizon.

At length he said:

“Steer west, skipper—due west.”

Frank complied with this.

The air-ship sailed westward for several hours. And still the great expanse of water lay beneath. Frank reckoned it full two hundred miles from shore to shore.

At length the western shore became well defined.

And now as they approached it, a curious thing was observed. The waters of the lake seemed to have risen and flooded a part of the country beyond, so that the water was full of trees and tangled brush.

Nicodemus was surprised.

“This was not the case when we were here,” he declared; “it is curious. I can see nothing of the shore where we rested.”

“It is under water,” said Frank.

“Yes.”

“Well, can you guess at the locality?”

“Yes. Yonder peak was north by west. Here—here was about the spot where we camped. The gold mound should be three miles or more in that direction out in the lake.”

These facts established, the interest of all reached fever height. The air-ship was held stationary over that spot.

A discussion was now held as to the best course to be pursued.

“Of course we can do no better than to wait for the disappearance of the lake,” said Nicodemus. “That may happen at any time.”

“Is there any regularity to the event?” asked Frank.

“That I cannot say,” replied the captain. “We were here but a few weeks, and the lake disappeared and reappeared only once in that time.”

“I have to suggest, then,” said Frank, “that we sail over to that distant peak and wait there until some change comes.”

The peak in question overhung the lake, so that its disappearance could be instantly noted.

The plan was adopted.

Soon the Spectre was resting upon this mountain height. A good spot was found for the air-ship to rest.

Night now shut down rapidly. As all on board were intensely weary, they retired early to rest.

Barney was left on guard. The night was black as Erebus.

The Celt sat in the bow of the air-ship where he could easily reach the valve of the searchlight. There was no danger of his sleeping at his post.

As the hours wore on, Barney relaxed his vigilance somewhat. It was past the hour of midnight when an unlooked for thing occurred.

A curious sound came from the distance over the lake.

It was a strange sullen roar and a curious sound like the suction of water through an orifice.

“Begorra, that’s a queer sound,” he muttered. “Phwativer can it be?”

He listened again.

Then he acted upon impulse and turned on the full glare of the searchlight. The pathway of radiance shot out over the lake.

Barney had expected to see the shimmer of the waters.

But he was startled at the fact that they were not visible. The glare of light showed only sand and rocks and weeds.

The pathway of radiance extended for fully a mile. But nowhere was water visible.

“Tare an’ ’ounds!” gasped the Celt, “phwat the divil is the maning av that?”

For a moment he was stupefied.

Then the realization of a startling truth dawned upon him. He sprang to his feet.

“Mither presarve us!” he muttered, “the lake has gone an’ disappeared, as the captain said it would.”

He started for the cabin to call Frank and the captain. But before he reached the cabin stairs second thought impelled him to change his mind.

“Divil a bit,” he muttered; “there’s no nade av that. Shure, they’ll see the thing fer thimsilves to-morrow, an’ to chate thim av their sleep now wud be foolish enough.”

So he went back to his post.

He flashed the rays of the searchlight over the sandy bed of the Transient Lake. Satisfied that there was no error, and that the lake had really departed, he finally shut off the rays and abandoned himself again to his duty of pacing the deck.

The night wore on.

Usually Pomp would come on duty to relieve him before the morning hour. But this night Barney had agreed to keep the full watch, if Pomp would do the same the next night, giving each a chance for a full night’s sleep.

Toward morning Barney relaxed his vigilance and sat in the cabin doorway, communing with his thoughts. It was just daylight when he heard a movement below.

He saw Frank Reade, Jr., cross the cabin.

Instantly he cried:

“Och hone, Misther Frank, shure I’ve a surproise for ye. The lake has gone intoirely, sor!”

This assertion created a sensation.

CHAPTER VII. A STARTLING SURPRISE.
Frank gave an exclamation and started for the stairs.

“What is that you say, Barney?” he cried.

“Shure, sor, the lake has gone!”

Frank gave a loud shout.

“Heigho, Beere!” he cried, “the time for action has come. We are just in time. The lake has gone out.”

“Eh—w—what?” sputtered the captain, rolling out of his berth. “You don’t mean that?”

“Yis, sor, for I saw it wid me own eyes!” cried Barney, “shure, cum up an’ ye kin see fer yersilf.”

The captain leaped into his trousers. Then he sprang up the cabin stairs with Frank.

In a moment all were at the rail. Then there was an astounded silence.

Barney’s hair fairly rose on end. He gazed down below, then up at the sky, then around him. Then he gasped for breath.

“Mither av Moses! Did ye iver see the loikes! Shure it has cum back agin!”

Both Frank and the captain looked sharp at the Celt.

There below them was the sparkling surface of the lake. It presented just the same appearance and was just as high as when they had last seen it the night before.

“Barney,” said Frank, severely, “have you been drinking?”

The Celt stuttered and stammered and acted very foolish. But he managed to say:

“Be me sowl, Misther Frank, it was gone, and not an hour since, sor. I saw the sand an’ the rocks ’an’ all, sor!”

Frank and Nicodemus exchanged glances.

“What time was it when you discovered the disappearance of the lake, Barney?” asked Nicodemus.

“About two o’clock av the mornin’, sor!”

“Tell us all about it.”

Barney did this. Frank and the captain listened with interest. When he had finished Nicodemus said:

“Frank, there is no doubt of it. The lake went out and came back again while we were asleep.”

“It must be so,” agreed the young inventor.

“Shure, sor, it’s thrue,” averred Barney.

“Why didn’t you wake us up and tell us about it?”

“On me worrud, sor, I niver had a thought that it wud cum back again, sor, an’ I med out to wait until mornin’ rather than disthurb yez sleep, sor.”

“Well,” said Frank, turning to Nicodemus, “it is hardly likely that we could have accomplished anything anyway in that brief time.”

“That is true,” agreed the captain. “We will wait for another evacuation of the lake basin.”

All that day the little party watched the lake. That night all sat up until late to see if the lake would go out again.

But it did not. The next day brought no change, and thus several days passed.

Still the same smooth expanse of water smiled upon them every morning.

There seemed no reason for believing that it ever would or could change its basin.

A week passed thus.

Waiting and watching of course grew extremely monotonous. So after awhile diversions were indulged in to pass away the time.

Hunting trips were made into the interior of the mysterious country.

Many strange things were seen, and once a glimpse was had of a mighty cavern mouth far up in the hills, in which there were grouped a dozen of giant men.

They were no doubt of the giant race which inhabited those mountains. It seemed as if they must be fully seven feet in height and of enormous build.

Our adventurers took good care to keep out of their way, for a collision with them might not be pleasant.

Two weeks drifted by.

Then the first of a series of thrilling events occurred.

Nicodemus arose early one morning and walked around the far shore of the lake.

He was pacing the sands abstractedly when his eye caught something in the sand.

He paused with a gasp.

It was a footprint.

Moreover it was that of a man who wore a hobnailed boot. It could only prove one thing.

Others were in the region and they were also from civilization. Words cannot express the captain’s amazement.

“By Neptune,” he muttered, “how did they ever find their way to this out of the way place?”

Then other queries came to him. Who were they? What brought them here, and how many were in their party?

The captain’s curiosity was aroused.

Prudence bade him return to the air-ship and secure the co-operation of his companions. But powerful curiosity overruled discretion.

He bent down over the trail and followed it. A little further on as he had expected, the footprints met with others. For two miles he followed them along the shore.

Then he turned an angle in the shore and came upon a startling scene.

This was a camp in the verge of a clump of palms. A dozen brawny men in white shirts, loose trousers and sombreros, were sitting about smoking and talking.

All the paraphernalia of a camp, with a train of mules, was behind them. They had apparently been on the spot for some while.

Words can hardly express the sensations of the captain.

He stared at the scene, and then a sharp ejaculation escaped him.

“By Neptune! it is Jerry Dooley!”

His gaze was fixed upon a man who stood in the edge of the camp talking with three others. He was a man of smooth face, shifting gaze and stealthy manner. His appearance was that of a sea-faring man.

In him Nicodemus recognized one of the crew of the wrecked ship, who had been a companion of his at the time that the lake came back, and as Nicodemus had always believed, had drowned the entire crew left at the mound of gold.

But there had been one exception. This was Jerry Dooley, the ship’s steward. As fate had it, he had started himself right after Nicodemus and Langley to go back to the camp on an errand. He was overtaken by the waters of the lake, but dashed high and dry upon an eminence on the lake shore.

Dooley had made ineffectual search for the camp, and not finding it, finally started back for the Pacific coast.

After many hardships he reached it and pluckily put to sea in the ship’s boat left there. Good fortune became his.

He was picked up by a coaster bound for Valparaiso and later got a berth aboard an American ship of the line. Later he went into the navy.

But he had never forgotten the Transient Lake and the mound of gold. He believed all his companions dead.

He succeeded in the navy and became a lieutenant, finally being retired on half pay. Having the leisure time he now decided to carry out a long-cherished desire.

This was to pay a visit again to the Transient Lake, and if possible recover the buried treasure. He succeeded in organizing a party.

For a year they had floundered about in the swamps of Paraguay, and finally crossed the wild ranges of Chuquisoca, and by a stroke of luck found the lake.

And here they were encamped and waited for precisely the same thing that the aerial voyagers did, viz: the disappearance of the lake.

This much Captain Nicodemus guessed. He was so excited at the outlook that he inadvertently stood out in full view of the camp.

And just then Dooley, chancing to look up, saw him.

He gave a start and for a moment his face was livid. Then he started toward Nicodemus.

The captain saw that he had betrayed himself, so he did not attempt to conceal himself. Instead he advanced to meet the other.

“Dooley!” he exclaimed; “on my word, this beats all. I thought you dead.”

“And I thought you dead, skipper,” declared the lieutenant.

“What—when—how—what are you here for?”

The lieutenant looked sharply at the captain. In that moment each understood the other.

“I have come back for the gold in the bottom of the lake,” said Dooley.

The captain stiffened visibly.

“You have!” he exclaimed.

“Yes.”

“Do you expect to get it?”

“Not unless the lake again changes its basin.”

“Oh, umph! Let me see. Were not your companions drowned when the lake returned that time?”

“They were.”

“But you—how did you escape?”

Dooley told his story. Then he asked sharply:

“But how did you get here? You have not been here ever since?”

“Hardly,” replied Nicodemus, quietly. “I have come here for the same purpose as yourself, for the buried gold.”

“Ah!”

The two men gazed at each other. In that moment antagonism was uppermost.

“I suppose that gold belongs to whomever can recover it.”

“Certainly not!” replied Nicodemus.

“Indeed!” said Dooley, somewhat staggered. “How do you disprove that?”

“Easy enough. My right to it is indisputable, and confirmed by the law of prior discovery. The gold is mine!”

Dooley drew a deep, sharp breath. Matters were becoming strained.

“I disagree with you,” he said.

“Eh?” roared Beere.

“I do not agree with you.”

“What do you mean?”

“Just this: We have as much title to that gold as you. It was to have been equally divided at the time. It shall be so now.”

“By what authority?” asked Beere.

“The authority of fair play. We have come thousands of miles, have dared death in every form, and we are not in a mood to sacrifice the prime object of our expedition.”
CHAPTER VIII. THE ATTACK ON THE AIR-SHIP.
Nicodemus had expected something of this kind from the moment he had first seen Dooley on the spot. He knew that trouble could not be averted.

The latter rascal, for such he really was, was keen enough to read all this in Beere’s face.

He was backed by a dozen hardy men himself, and he did not believe that the captain was so well supported. So he was uppish.

Beere gazed steadily at the other for a moment after this virtual declaration of war, and said:

“The largest share of that gold belongs to me. You shall have a fair share. Is not that fair enough?”

“My friend,” said Dooley bluffly, “mighty little of that gold you’ll see, I can tell you. It belongs to me. I claim it and shall divide it as I see fit.”

“You will?”

“Yes.”

“You are a scoundrel!”

“Easy! I can make trouble for you. Back of me are a dozen faithful fellows who will do anything. It will not pay you to dare me.”

Beere was now furious.

He made a menacing gesture.

“You atrocious rascal!” he gritted. “I’ve a mind to flog you!”

“We’re not aboard ship now!” sneered Dooley. “By the way, I am inclined to believe that you are a dangerous character and ought to be taken care of. Hey, boys!”

He blew a shrill whistle. The result was electrical.

Instantly the two men were surrounded. Dooley made a quick sign, and heavy hands were laid on Beere.

The captain saw in that moment that he was in bad hands.

The rascally Dooley certainly meant him harm. The old captain’s blood was up.

“Avast, ye dirty lubbers!” he roared. “I’ll keelhaul every mother’s son of ye if ye lay hands on me. Mark my words!”

“Tie him up!” yelled Dooley. “Seize him there!”

Beere let out with two sledge hammer blows, which were like the kick of a horse. A man went crashing down with each blow.

Then he was overpowered.

He was a strong man and fought furiously. But the odds were too great. He was obliged to succumb.

Dooley was exultant.

“We have come too far, boys, to have any living man stand between us and that gold.”

The others cheered. Then the villain continued:

“Tie him up to that tree yonder. First, I want to learn whether he has any companions or not.”

Then he interrogated his prisoner.

“Tell me the truth, Beere,” he said, sternly; “how many companions have you, and where are they?”

“You must learn that for yourself,” said Beere, firmly. “I can give you no information.”

A curse dropped from Dooley’s lips. He took a step toward the prisoner, saying menacingly:

“We’ll find a way to open your mouth. Before I’ve done with you you’ll be glad enough to talk.”

But Nicodemus was not to be intimidated, though the situation was a serious one for him. He refused to say anything.

But the villains organized a trailing party and followed his footprints backward along the beach. When they had reached a certain angle they looked up and beheld the air-ship.

It was an astonishing spectacle to them.

They managed to creep up near enough to the Spectre to see three men aboard her, one of them colored, and then they returned to their camp.

It was easy for Dooley to decide upon a move.

“We must capture that hurdy-gurdy,” he said; “how in the world it got away up there on that shelf of rock, I do not know.”

The villain did not know that the Spectre was an air-ship. He had fancied it some sort of water craft.

He proceeded to arrange for a descent upon and the capture of the air-ship that night. He felt sure of success.

Meanwhile Frank and Barney and Pomp had been attending to the routine of their duties aboard the Spectre.

It was some while before the captain’s prolonged absence was noted. Then Frank ventured to say:

“Do you think anything has happened to Beere? He ought to be here now.”

“Begorra, that’s thrue!” cried Barney. “Phwere did he go at all, at all?”

“I done seed him goin’ along dat shore early dis mornin’!” declared Pomp.

“Then he is surely in trouble!” said Frank. “We had better set out to look for him. Come on, Barney!”

The young inventor picked up his rifle and flung himself over the rail.

“All roight, sor!” cried Barney, hastening to join him. Frank turned to Pomp, saying:

“Keep a sharp lookout, Pomp. We will be back as soon as possible. Remember, we’re in a dangerous country.”

“Yo’ kin be sure ob dat, sah,” affirmed Pomp. “Neber fear, sah.”

Frank and Barney were quickly on the beach. They walked on until they came upon Nicodemus’s tracks. Then a startling surprise was accorded them.

There were other tracks.

“By Jupiter!” exclaimed the young inventor in amazement, “what does this mean? The captain has fallen in with others and they are civilized also.”

There was nothing to do but to follow the trail. The result was that, after two miles of patient tramping, they came upon the camp of Dooley’s men just as the captain had.

Only they were wiser and kept out of sight.

This was a praiseworthy precaution. Moreover they were directly astonished to see Nicodemus tied to a palm tree. A rascally-looking fellow was just organizing a party of a half dozen armed men.

It looked as if they were going to venture forth upon some daring errand. A startling thought came to Frank.

These men were certainly foes. Their capture of Nicodemus showed that. Was it not their purpose to attack the air-ship?

Frank’s first impulse was to beat a hasty retreat and give them a hot reception. But second thought changed his mind.

He thought of Nicodemus and saw that he needed succor.

“Pomp will be on the outlook,” he reflected; “he can easily fool them. Our duty is here.”

So he whispered to Barney to crouch low in the bushes and await developments.

They were not long in coming.

Dooley and five of his men, armed to the teeth, set forth to capture the air-ship. This left five men in the camp with the prisoner, Beere.

Captain Nicodemus was in a very despondent state of mind. Just as despair was getting a firm grip on him he heard a sibilant whistle at his elbow.

It was so low that it did not travel beyond his ears. He turned his head eagerly.

Then a whisper came to him.

“Don’t get discouraged—we are here to rescue you.”

“Good!” returned the captain. “You missed me?”

“Yes.”

“These fellows are our foes. They are led by Jerry Dooley, one of my ship’s crew, who has come back here for the gold. They will give us trouble.”

Barney had crept up behind the tree. He skilfully cut the prisoner’s bonds.

“Now, sor,” he whispered, “whin the omadhouns ain’t lukin’ at all jest slip into the bushes and cum wid us. Shure we must be afther gittin’ back to the air-ship.”

“All right, Barney,” agreed the captain.

And at the right moment he obeyed the suggestion. In the undergrowth he joined Barney and Frank.

The trio ran hastily along the shore in the verge of the palms. They had made several hundred yards before a loud roar announced that their escape had been discovered.

Then came pursuit.

But they had start enough to keep out of the way. And right here Frank employed a stratagem.

Showing themselves for a moment on the beach, the fugitives next dashed into a copse near. Here they hid while their pursuers ran by them.

The danger was momentarily over. But the fate of the air-ship now became the engrossing subject.

Would Pomp be sufficiently on his guard to repel the attack? But the question was the next moment answered in a satisfactory manner.

The distant rattle of firearms was heard.

“They have made the attack,” cried Frank. “Now all depends on Pomp.”

“Niver yez fear for the naygur,” cried Barney. “Shure, he’ll fool thim aisy enough.”

The rattle of the guns grew momentarily more rapid and clear. It was plain that Pomp was giving them a hot reception.

But that the overpowering numbers would result in the capture of the air-ship would seem certain unless the darky should employ different tactics. And this he was shrewd enough to do.

Seeing that the foe were preparing to charge upon him, the darky acted accordingly.

He sent the air-ship aloft instantly. His companions in hiding below suddenly saw it appear just above them.

“Hurrah!” cried Frank. “Pomp was on his guard. The air-ship is safe.”

“It must be a surprise to Jerry Dooley,” said the captain.

“Bejabers, I hope the naygur will be afther seeing us,” cried Barney. “It’s a foine pickle we’ll be in if he don’t.”

“Oh, I think he will,” said Frank. “Suppose we try a signal!”

The young inventor drew from his pocket a small battery and a steel tube with a pneumatic chamber. He held this tube up a moment and pressed a button.

There was a sharp ping, a recoil, and up into the air shot a small ball of fire. Up it went, and exploding, fell in a shower of sparks.

“My electric rocket,” said Frank, explanatively. “I don’t see how Pomp can fail to see that.”

“Divil a bit!” cried Barney, with exultation. “See, shure he’s got his eye on us already.”

The air-ship came about and bore down rapidly to the spot where the trio stood. Pomp was seen at the pilot-house window.

Down it sank as the darky saw them, and stopped not fifty feet from the ground. Then the darky ran out and threw over the gang ladder.

“Huh! I’se drefful glad to fin’ yo’!” he cried with delight in his voice.

CHAPTER IX. A FUTILE QUEST.
It is needless to say that the three adventurers lost no time in climbing up the gang ladder.

They were not a moment too soon.

Frank had just cleared the rail when men burst from a thicket and sent a hail storm of bullets upward. They rattled on the steel hull of the air-ship.

“Give it to ’em!” shouted Nicodemus, angrily. “They deserve it richly.”

Barney and Pomp grabbed rifles and rushed to the rail.

But Frank cried:

“Wait! Do not take life unnecessarily! We are safe just now. Let us have a talk with them.”

Taking care not to expose himself, Frank shouted over the rail:

“Ahoy down there!”

The firing had ceased, and a voice—that of Dooley—came up in reply:

“Well, what do you want?”

“What do you mean by this unprovoked attack upon us?”

“You are our enemies!”

“How do you prove that?”

“Have you not come here to cheat us out of the gold buried under the lake, and which justly belongs to us?”

“Neither of us are able to secure it just now.”

“Well, but we shall be when the lake recedes.”

“In that event, why have we not as much right to a share of it as you?”

“That is neither here nor there. We lay claim to the gold, and don’t propose to divide with anybody.”

“What a pig-headed fellow,” said Frank, angrily. “I’ve a mind to teach him a lesson!”

“I wish you would,” said Nicodemus, eagerly.

“Look here, my friend,” shouted Frank, “let’s have no nonsense about this. That gold does not belong to you more than it does to us. For that matter, if I should choose, I could prevent your securing one jot of it. It is better for you to talk reason at once!”

“The only reason I will talk with you,” said Dooley, obstinately, “is that you go on about your business and leave us and our affairs alone!”

Frank turned from the rail.

“There is no use to talk with that fellow,” he said.

“What shall we do?” asked Nicodemus.

“I will think up a plan,” said the young inventor, “in the meanwhile our best plan is to sail over to the other side of the lake and wait for it to recede. When it does we must be first on the scene where the gold lies.”

“Good!” cried Nicodemus; “if they attack us there——”

“Then it will be time enough to retaliate!” declared Frank.

And so the matter was settled.

The Spectre sailed away across the arm of the lake and landed upon the summit of a small hill. It would have required several days’ journey for the Dooley gang to have made the circuit around by the shore.

So the aerial voyagers felt safe. But this new development had put a different face upon matters.

However, if the lake should again recede, the air-ship could easily cover the three miles to the mound of gold before the men on foot could.

Frank nor Nicodemus either cared for but a fair share of the treasure. But the unfair and unreasonable conduct of Dooley impelled them to seize the whole of it if they could.

Another day and night passed and yet the lake presented the same smiling and smooth appearance. But that afternoon a curious thing happened.

Barney, who was on deck, noted a curious yellow cloud rising from the west.

It mounted upward rapidly and soon had assumed angry proportions. The sun was hazy and the landscape took on a sickly appearance.

“On my word!” cried Frank, “it looks as if we were going to have another Andean storm.”

“Jericho!” exclaimed Nicodemus, “don’t say that. We had better anchor the air-ship hereabouts if that is true.”

All watched the cloud until the whole western sky was obscured. Then there was a distant rumble, lightning shot across the heavens.

The ground began to rock and pitch violently, trees and shrubs swayed and were bent to the ground, the air-ship was tossed about like a pebble, and no man could stay on his feet a moment.

“An earthquake!” gasped Frank.

“Bejabers, wud yez luk at the lake!” cried Barney.

All gazed in that direction and were dumfounded at the fearful spectacle presented.

The lake was like one mighty whirlpool, and went swirling about like a vast maelstrom. Its waters seemed to be receding every second.

Then the white sands of the shore line began to widen. Islands appeared in its surface.

The truth was plain.

The Transient Lake, impelled no doubt by the earthquake, was about to make one of its periodical disappearances.

Round and round swirled the waters. The ground had now ceased shaking.

But the yellow cloud continued to vomit lightning until it had passed beyond the zenith.

The aerial voyagers now all pressed to the rail and watched the wonderful phenomenon of the lake’s disappearance.

And, indeed, such it was.

Lower and lower sank the swirling waters. Suddenly they ceased their commotion.

Then they became like glass. In a few moments they were like a mirror.

But rapidly now they sank. From the distance there came a strange noise like water running through a funnel.

This was the sound Barney had remarked a few nights before. Ten—twenty—thirty minutes elapsed, and then, as far as the eye could reach, no water was to be seen.

The glistening sands and rocks were rapidly drying in the sunlight. The Transient Lake had once more gone out.

How long it would remain was uncertain. Hours, perhaps, and maybe days. However, this was the time for action.

“Now for the mound of gold!” cried Frank. “We shall have to get our bearings from you, captain.”

“All right!” cried Nicodemus, studying the shore a moment. “North by east, skipper!”

Barney started the air-ship forward in the direction indicated. Soon the lake bed was beneath them.

As the Spectre sailed on over the sands, suddenly Nicodemus clutched Frank’s arm and said:

“There they are!”

A body of men were seen rushing rapidly across the lake bed. They were Dooley and his gang.

They could not help but see the air-ship, and even at that distance fired a number of shots at it. But of course they were without effect.

Meanwhile the Spectre rapidly left them out of sight.

Three miles was a distance easily covered by the air-ship, and suddenly Nicodemus clutched Frank’s arm and cried:

“There is the spot! Between those round hills! See it?”

Frank sprang to the keyboard and taking the lever from Barney, steered the air-ship down between the little hills of wet sand.

A moment later the Spectre rested on terra firma.

And there was the stone mound for a fact. It was just as the party had left it years before, so Nicodemus declared.

The captain was so excited that he hardly knew what to do.

He finally managed to procure a shovel and with Frank climbed over the air-ship’s rail.

In a few moments the two men were alongside the mound.

The captain hastily dropped his shovel and climbed to the top of the mound. He removed the stone cap and peered down into the place.

He remained in this position for a long time and Frank had thought of speaking to him, when he suddenly arose.

His face, as he turned it toward Frank, was white as chalk.

“By whales!” he said huskily, “it is not there, Frank!”

“Not there?”

“No.”

“What do you mean?”

“The gold—the gold is gone!”

Frank was so overcome with surprise and dismay that for a moment he could say nothing.

Then Nicodemus climbed down and faced his companion. His expression of face was strange to see.

“Are you sure it is not there?” asked Frank.

The captain nodded.

“I could see every corner of the cavity,” he said. “It is not there.”

“What! Who could have removed it?”

The captain gave a sudden start and smote his knee.

“Why did I not think of it?” he exclaimed. “Of course the ship’s crew did it while Langley and I were on our way to the camp.”

Frank’s face lit up.

“That is probably the truth,” he agreed. “Why didn’t we think of it before? Doubtless they removed the gold just before they were overtaken and drowned.”

“In that event——”

Nicodemus paused. Frank finished the sentence.

“What did they do with it?”

This was a question not easily answered. A close search of the vicinity failed to disclose any evidence of gold.

If it had been deposited just outside the mound and left there, no trace of it could be found.

On the other hand, it did not seem possible that the fated men could have carried such a quantity of the precious metal any distance away with them.

If they had, then it must be found with their bones somewhere in the vicinity.

There was a possibility that in the intervening years some other parties had visited the spot and carried off the gold. But this was only a faint chance.

However, one fact was patent.

The gold was gone.

What had become of it? Certainly it could not have taken wings and flown away of itself. The two gold seekers were completely mystified, and knew not what to do.
CHAPTER X. A COMPROMISE.
However, time was valuable.

Dooley and his men were momentarily nearing the spot. A conflict with them must be avoided.

But Frank first suggested that a thorough search of the vicinity be made.

This was done.

Every suspicious looking sand heap, far and near, was thrown over. No gold was found.

It was speedily seen that the quest was destined to be like looking for a needle in a haystack.

It was a reasonable supposition that the ship’s crew had removed the gold, and had started for the shore with it when overtaken by the flood. To find it now, or their bones, would require a long and patient search.

An hour had already slipped by. Dooley and his men could not be far away.

Within a radius of several hundred yards a thorough search was made.

Then distant shouts announced the arrival of Dooley. The aerial voyagers retired aboard the air-ship.

Then they tried in vain to consider the best and most logical move.

“Confound these chaps!” said Frank, angrily; “they are delaying us badly and making it as difficult for themselves to recover the gold as for us!”

“They ought to be given a lesson,” said Nicodemus.

“Ah, but I would have to redden my hands with their blood!” said Frank, “which I do not wish to do.”

“That is true. But how are we going to dispose of them?”

“That is a problem.”

The Dooley gang had now come into view upon a sand hill near. There they halted and regarded the air-ship in

The aerial voyagers every moment expected a shower of bullets.

But to their surprise these did not come. Dooley changed his tactics, very likely upon the cardinal principle that discretion is the better part of valor.

Down from the height came two men carrying a white rag on a gun barrel. One of these was Dooley himself. When within speaking distance, they halted.

“Ahoy the air-ship!” shouted Dooley.

“Ahoy!” replied Nicodemus.

“We want to parley.”

“Spout away!”

There was a moment of silence. Then Dooley resumed:

“I have reconsidered my determination of a few hours ago in regard to the treasure. On the whole I believe a just division no more than fair!”

Nicodemus turned with a gasp to Frank:

“Well, of all assurance,” he exclaimed, “the scoundrel thinks we have the gold, and, of course, is cunning enough to see that this is his only hope of getting any of it.”

“He is a scamp,” said Frank, “evidently he thinks we are soft.”

“But that is his mistake.”

“Rather!”

“What shall I tell him?”

“Let me talk with him.”

Frank went to the rail.

“So you have really changed your mind, Mr. Dooley!” with sarcasm.

“Yes, I was a little hasty,” replied the villain; “I did not consider the matter sufficiently.”

“Well, you probably think you are dealing with fools.”

“Eh?” gasped the villain.

“We have not the slightest idea of adhering to the terms suggested at this late day.”

“What! You are not going to keep all that gold yourself?”

“We have not got it.”

Words cannot depict Dooley’s utter amazement.

“Not got it?” he repeated.

“We have not.”

“Why—who has then?”

“We do not know.”

“Then it is gone?”

“Yes.”

Loud and bitter curses broke from Dooley’s lips. He ran forward almost to the air-ship’s rail.

“Then there has been some treachery at work,” he declared—“some hocus-pocus game. I tell you there is the mound where the gold was——”

He turned suddenly and sprang upon the mound. A glance into the interior satisfied him.

With livid face he descended. He came nearer to the air-ship’s rail.

“Where can that gold have gone?” he asked, huskily; “has some other party been here before us?”

“I cannot answer that question,” replied Frank; “but one thing is certain, the gold is gone. Our theory is that the ship’s crew departed for the shore with it and were overtaken by the tidal wave on the way.”

“In that case the gold is with their bones.”

“Yes.”

A light of hope lit up the villain’s face. He averted his gaze, and continued shrewdly:

“We must search for it.”

“Yes,” replied Frank, “that is the only way. But if we are to be foes all the while——”

“No, no,” cried Dooley, craftily; “we will not fight each other. It shall be agreed that whoever finds the gold there shall be a fair division.”

“Will you swear to that?”

“Yes.”

“All right,” said Frank, sternly; “but now let me impress upon you one fact. We have the best of the situation. If you attempt any treachery or go back on your agreement, I’ll exterminate the whole of you. With my air-ship I can do it.”

The rascal’s shifting gaze met Frank’s a moment. He could not help but see that the young inventor was in earnest. So he said with an affectation of servility:

“You need have no fear. I always stand by my agreement.”

Dooley went back to his men. Frank turned back from the rail and met the approving gaze of Nicodemus.

“You handled him well, Frank,” said the captain, approvingly. “Nothing could have been better.”

“Now we can search for the gold with safety.”

“Yes.”

Pomp took his position at the wheel and keyboard. Barney and Frank and the captain were to prosecute the search.

Already Dooley’s men were at work. They were scattered in all directions digging up the sand and following every sign of a trail.

Alighting from the air-ship, our trio of adventurers went forward.

Captain Beere’s hypothesis was that the men must have set out with the gold in the direction of the camp. So they proceeded that way.

Long and persistent and careful was the quest. Finally the day drew to a close.

As it was useless to attempt the quest in the darkness, Frank and his companions returned to the air-ship. The others bivouacked near.

Our adventurers were extremely weary with their day’s work. As soon as they had partaken of the hearty meal prepared by Pomp it was proposed to turn in.

And this they did. Pomp was left on guard, to be relieved by Barney in the early morning hours.

The darky paced the deck until long past midnight. Then he heard a low, sibilant whistle come from the gloom. In a moment his rifle hammer rose.

“Who am dar?” he asked, sharply.

“Easy, nigger! don’t get excited,” came back the reply. “I’m only one of Dooley’s men.”

“Wha’ yo’ want?”

“It’s durned lonesome up thar. Hev you got a chaw of terbacker?”

Pomp saw nothing in this request that could imply harm. The natural good-fellowship of man to man warmed within him, and he was too generous a soul not to reply.

“Reckon I hab, sah. Cum down yere an’ I gib yo’ a hunk!”

“Thank yer.”

A hulking form came down from the gloom to the air-ship’s rail. A grimy hand clutched the tobacco.

“Ugh! that’s good terbacker. Reckon you ain’t found no gold yet.”

“Not a bit,” returned the darky; “don’ keer much fer sich stuff mahself.”

“Jest my sentiments presactly. I wouldn’t give thet terbacker fer the hull of it. Any objections if I sit up thar wid ye? I’m powerful lonesome an’ wish I was back in Charleston.”

“You from Charleston, eh?”

“Yes.”

Pomp hesitated a moment. Yet he could see no harm after all. He was armed, the other was not. Neither did he believe any treachery was intended.

So the fellow, who gave his name as Jack Bowler, able seaman, came over the rail, and the two had a social chat. An hour drifted by.

Pomp had waxed real friendly with his new companion and was pleased to be able to have some one to help him while away the night hours and help keep guard as well.

The fellow told many entertaining stories of life upon the high seas, and all went smooth as a marriage bell for a time.

Suddenly Jack Bowler asked:

“What time are ye relieved?”

“About three o’clock, sah,” replied Pomp; “dat I’ishman he gib me a chaince to sleep den.”

Bowler knocked the ashes from his pipe. Then he leaned over against Pomp, and whispered:

“Look forward there! Don’t ye see somebody?”

Pomp turned his head in the direction indicated. Fatal move it proved for him.

The next moment the world swam about him, and then he knew no more.

With terrific force Bowler had struck him over the head with a heavy iron instrument. The negro’s head was proverbially hard, but it was not hard enough for that.

In an instant Bowler was upon his feet.

He took a step toward the cabin and listened. Then he gave a shrill, hardly audible whistle.

Down through the gloom from the camp above came a number of dark forms. Over the rail they came.

One of them whispered to Bowler:

“You did your work well, Jack. The rest are in the cabin, are they?”

“They are, cap’n. We ought to make sure of ’em in their sleep. Dead men tell no tales.”
CHAPTER XI. A TREACHEROUS GAME.
But Dooley, for he it was, said sharply:

“No! You mustn’t kill one of them. I want them held for prisoners. I have a purpose in view!”

“All right!” said Bowler, sullenly.

Toward the cabin door the interlopers crept. In a jiffy they had taken possession of every part of the air-ship.

A terrible peril hung over the heads of our sleeping voyagers, and yet they slept on, all unsuspecting it.

Frank Reade, Jr., was awakened from his slumbers by a savage clutch at the throat. Strong hands forced him down and bound him.

The captain made a terrific resistance but was overpowered. Barney was also served the same.

The aerial voyagers were thus all made prisoners in a twinkling. It was a sudden turning of tables.

The jubilation of Dooley can hardly be described in words.

That the villain’s plans should have succeeded so well was remarkable.

He glowered at Frank Reade, Jr., saying:

“Well, now, ye can afford to be a little more civil with me, can’t ye? Oh, I tell ye, Jerry Dooley is a hard man to beat!”

“You are a treacherous dog,” said Frank, angrily, “after making a truce, to treat us thus.”

“All is fair in war,” quoted the wretch. “You are lucky to have been spared your lives.”

“What do you expect to gain by this trick? We have none of the gold.”

“What have we not gained?” exclaimed the villain, exultantly. “Only think—the wonderful air-ship is ours, to become freebooters of the skies if we choose, and the inventor is our hostage.”

Frank smiled grimly.

“So you intend to make use of the air-ship?” he asked.

“Why not?”

“You will find it not an easy machine to manage, I think.”

“Ah, but that is why I spared your life. You shall manage it for us.”

“Indeed!” said Frank with anger. “You have reckoned without a host. I shall do nothing of the kind.”

An ugly light shone in Dooley’s eyes.

“You won’t, eh?”

“Never!”

“Well, we shall see. You may be induced to change your mind. Make no rash announcements!”

“Oh, for a moment of liberty,” muttered Frank, gnashing his teeth. “I would pluck that rascal’s wings for him.”

“I wish you had it, Frank,” said Nicodemus; “is there no way we can turn the tables upon them?”

“We can only wait and hope,” said Frank.

Barney was raving and raging furiously.

“It’s the stupid work of that naygur,” he cried angrily. “Shure av they’ve finished him it’s small loss, afther givin’ us roight inter the hands av the inemy, bad cess to him!”

Meanwhile the gold seekers had overrun the air-ship.

There was no part of it to which they did not penetrate. Everything on board was subject to scrutiny.

No move was made, however, to change the position of the air-ship until daylight came.

Then Dooley and several of his companions undertook to make an examination of the electrical machinery.

It probably occurred to them that they might fathom its construction and learn to operate the air-ship themselves.

But they were bewildered with all its intricacies and were speedily obliged to abandon that idea. They finally went into the pilot-house and began trifling with the keyboard.

And right here they made a mistake. For by an inadvertence Bowler pressed the helice lever wide open.

What happened was a literal surprise to all.

There was a terrific, whirring sound, and up into the air shot the air-ship. Bowler did not know how to press the lever back and could not therefore check the craft’s ascent.

Both he and Dooley rushed out on deck.

They stared down at the rapidly receding earth, half in fright. As it happened none of the other gold-seekers were aboard.

Dooley was angry.

“What the deuce did you do that for, Bowler?” he cried. “Now undo your work lively.”

“I can’t do it, sor!” replied the sailor, as he tried in vain to reverse the lever. It would not work.

“There is a way to do it,” cried Dooley, angrily. “Confound you for a blockhead! We shall soon get to heaven at this rate. Let me see it, you ass!”

But Dooley had no better luck! Still upward raced the air-ship. The two rascals were in a state of terror.

Cold perspiration oozed from their pores and they trembled as if with the ague.

“I didn’t mean to do it, skipper,” declared Bowler, aghast; “it was an accident. Won’t we ever get back to the earth?”

“Not at this rate,” huskily declared the senior villain.

And now an alarming state of affairs ensued. The air grew so rare that their eyeballs began to ache and cold chills seized them.

“Great Jericho!” gasped Dooley. “I can’t stand this. I’ve heard it said that when you get a certain number of miles up in the air you can find no air to breathe and you must stifle.”

“Great lobster pots!” wailed the terrified Bowler; “stop the thing some way.”

“I can’t,” said Dooley, in despair.

“I can!” came a calm voice from the cabin. Dooley wheeled as if shot.

In that instant he saw deliverance, and wondered why he had not thought of it before.

“Why, surely!” he exclaimed, “here is the man who made the condemned flying machine. Why didn’t I think of it. Tell me, sir, how shall I stop her ascending.”

“You cannot do it,” replied Frank, calmly.

“I can’t?”

“No, sir!”

“Can you?”

“Yes, sir.”

“Do it then, for the love of heaven. We shall perish in a few moments if you don’t.”

“How do you expect me to do it, tied up as I am?”

Dooley hesitated. It was plain that he feared a trick.

“Will you agree——” he began.

“I agree to nothing,” said Frank, sharply. “You are two to one. Cut my bonds quickly, or we’ll all strangle before we are aware of it.”

The villain hesitated no longer.

With a quick spring forward he cut Frank’s bonds. The young inventor leaped to his feet.

In a moment he reached the keyboard. He quickly shut off the current, and the air-ship fell.

Down she sank until the awful pressure on the lungs was removed.

All felt easier.

Then Dooley rushed into the pilot-house with a rope in his hand.

“Make no resistance,” he said, threateningly, “or you will die! You are our prisoners!”

“I have offered no resistance,” said Frank, coolly; “but I ask that you do not tie my hands again.”

“Why?”

“If you do, I cannot operate this air-ship, and that will be the worse for you.”

This was really an evasive answer upon the young inventor’s part, and he was casting about in his mind what move it was best to make to turn the tables on his foe.

“Eh!” exclaimed Dooley; “is it necessary for you to hold your hand on that brass shaft?”

“It is!” said Frank coolly. “See? if I take my hand off, it will stop the air-ship!”

The air-ship did stop. But Frank adroitly shifted the lever when he took his hand from it. This completely deceived the villain.

He hesitated a moment.

Then he drew a revolver.

He seated himself in a chair in the pilot-house door. He placed the weapon on his knee:

“All right!” he said, coolly; “keep your hand on that thing, then. If you take it off or make a move to play any gun game you shall die!”

For a moment Frank felt that he was worsted. The villain certainly had the best of him.

Then an idea came to him.

There would be some risk to the move. But without some risk he could hope to gain no victory.

While he held his hand on the lever he managed with his other hand to connect a small wire with the dynamo connections and the steel framework of the pilot-house.

Dooley leaned against the door frame, which was also of steel. Frank’s hope was to suddenly send a current from the dynamos strong enough to traverse the steel frame and shock he villain into insensibility.

So he carefully worked with this end in view. Dooley did not suspect a thing.

He saw Frank arranging the wires, but imagined all the while that this was only some mechanism of the air-ship which it was necessary to regulate.

As long as he held the drop on Frank as he did he felt comparatively safe.

But right here was his mistake. Had he ordered the young inventor to stop twisting the wires under the keyboard the situation would have changed in his favor. He failed to do so.

Hence his defeat.

It was all executed very swiftly and silently. The connection was made and Frank turned to the villain, saying, pleasantly:

“We are half a mile from the earth now!”

“Jericho!” gasped Dooley. “What a drop that would be!”

“Yes, a comfortable one.”

“Eh? I should think it would be a terrible one. Would it not mean death?”

“Possibly. That would depend upon the shock which would be something like—this!”

Frank made the connection.

In that swift second the steel frame received the full force of the dynamos. The villain could not know what struck him.

He sank down in a lifeless heap. Frank switched the current off, and with a leap gained his side. He picked up the revolver and covered Jack Bowler, who had come rushing out of the cabin.

“Great guns!” roared the sailor; “what’s the matter with the skipper—eh—what’s this?”

“Hands up, on your life!” cried Frank, sternly, “or you’re a dead man. I have the drop.”

One moment Bowler hesitated. His face turned ashen pale.

But he saw that the game was up. There was nothing for it but to surrender.

So up went his hands.

“By the gunnels!” he ejaculated, “you have got to windward of us after all. It’s good pluck.”

Frank made Bowler follow him into the cabin, while he cut the bonds of Nicodemus and Barney. Then both prisoners were bound. It was not likely that Dooley would come to very soon.
CHAPTER XII. THE END OF THE STORY.
All this while poor Pomp had been lying insensible upon a heap of mats in the after cabin, where he had been dragged and left.

But now the darky began to come out of his faint.

The blow upon the skull had inflicted no serious wound, and he must be all right again shortly. But for a time he was sick and dizzy.

Frank and Barney found him and gave him some stimulants. He very quickly recuperated.

Then he remembered his experience with Bowler on the deck. He felt somewhat crestfallen.

But Frank said:

“It’s all right, Pomp; you meant well, but the fellow was treacherous. Next time don’t get caught.”

“Yo’ kin jes’ bet on dat!” cried the darky. “I won’t trust nobody aftah dis.”

It is needless to say that the aerial voyagers were delighted with the result of the affair. Their deliverance was due to Frank’s shrewdness and marvelous ingenuity.

The two prisoners were confined in the after cabin. But it was now a question as to what it was best to do with them.

“Suppose we go down and talk with their companions!” said Nicodemus; “perhaps they will make up their minds to behave themselves and let us alone after this!”

“Very well,” agreed Frank. “We will try that.”

So down sank the air-ship. The gold seekers were seen grouped below in a state of much excitement.

Frank went to the rail and opened a parley with them.

“We have your two leaders, Dooley and Bowler, as prisoners!” declared the young inventor. “We want to know if you are going to play any more treacherous games upon

The gold seekers were evidently astonished at the turning of tables in so unexpected a manner.”

But finally they came to Frank’s terms and made fervid vows never to trouble the air-ship or its party again.

Their spokesman said:

“To tell ther truth, mister, we don’t believe in ther story of ther hidden gold an’ we’re sick of the whole thing. We’re goin’ back to Para.”

“Very good!” said Frank. “I will set your leaders free upon that condition.”

Then he went into the cabin and talked with Dooley and Bowler. They readily agreed to Frank’s terms.

“I shall follow you as far as the shore of the lake,” declared the young inventor; “if you dare to return I will drop dynamite bombs upon you and destroy you.”

Dooley was satisfied.

He saw that it was of no use to attempt to cope with the voyagers. Moreover, he had lost faith in the existence of the treasure.

He was in fact sick of the whole job and decided to return to America at the first chance. So he said:

“I’ll do as you say. I’m quits on this thing. It’s an accursed country, anyway.”

A short while later the two villains returned to their companions. They at once started for the shore of the lake.

Frank decided not to accompany them, for he saw that Dooley was in earnest.

As the villain dropped from the air-ship, Frank said:

“As an extra incentive, I will promise this, in spite of your bad treatment of us. If we find the gold I will overtake you and give you a fair division.”

Dooley hung his head and muttered abashed thanks. Then he and his party were off.

The aerial voyagers continued the quest for the gold. All that day they explored the sandy basin.

Toward night a find was made.

A number of human bones were mixed up with several hundred ingots of the yellow stuff. It was taken aboard the air-ship.

Frank estimated its value.

“There is about thirty thousand dollars in the pile,” he said, “there are twelve in Dooley’s party and four in ours. That will make about two thousand each on a fair division.”

“They are not entitled to any of it,” snapped Nicodemus.

“Perhaps not,” said Frank, “but we have banished them from the search and therefore ought to divide. At any rate I have promised it.”

“Oh, I don’t kick,” said the captain, cheerfully; “I am satisfied. It was not the gold I cared for so much as to solve the mystery of this lake.”

“And that we are now at liberty to do,” said Frank; “we will first overtake Dooley and his men and divide. Then we will do a little exploring.”

With this decision none found fault. So Frank took his leave of the treasure basin.

The gold seekers were overtaken on the shore of the lake. They were astonished at Frank’s generous announcement.

And when the gold was turned over to them Dooley wrung Frank’s hand and said:

“You’re the only square man I ever met in my life. I like your style. I’m going ter turn over a new leaf an’ do better.”

Then Dooley and his men set out to the eastward for the head waters of the Paraguay where they had boats. None of the aerial voyagers ever saw them again.

But one thing more now remained to be done to complete the success of the trip.

This was to find the source of the Transient Lake and if possible discover an explanation of its curious appearance and disappearance.

For full one hundred of the two hundred miles of its width the air-ship sailed over the lake. They were now very near the centre.

And here a mighty circular bowl-shaped basin was seen. It had curious galleries leading down into the earth.

These were cut out of the solid rock. This basin covered hundreds of acres. The air-ship was here brought to a stop.

“Here,” said Frank, positively, “this is the outlet of the lake, if anywhere.”

Nicodemus gave the place a critical glance. Then he said succinctly:

“Skipper, you’re right!”

And as fate had it, while they were watching the curious basin, a strange sound began to arise from it.

It was a dull, distant, hollow booming, and then suddenly little channels of water began to appear in the rock galleries.

“Begorra, it’s afther comin’!” cried Barney.

With interest the aerial voyagers watched the phenomenon.

Suddenly from an orifice in the centre of the basin there shot up to the height of fifty feet a great column of water.

Then in an incredibly short space of time from all the galleries there rushed forth great seething volumes, swift as the rush of Niagara.

And once full, the great basin overflowed in a second, sending a mighty tidal wave across the country at race-horse speed.

Small wonder that the ship’s crew had been overtaken and overwhelmed. Nothing could have outstripped that line of swiftly rolling water.

On all the wide earth Frank and his companions thought there could be no phenomenon to equal this.

It was without parallel. Within the incredible space of an hour the Transient Lake, tranquil and placid, was once more restored to its basin.

The air-ship hung silently over it. Birds shot across its surface, and small fish played in its limpid depths.

Above, the sky was calm and serene. A fierce tropical heat beat down upon all.

Captain Nicodemus turned to Frank.

“Well, skipper,” he said. “What do you think of it?”

Frank drew a deep breath.

“It is a wonderful freak of mighty nature,” he said. “I am satisfied. Let us go home!”

“Home!”

It was a magic word just now. The aerial voyagers had accomplished their project, and had explored the Transient Lake.

They had yet a mighty distance to travel, and after all there is no place like home.

So Frank turned the course of the air-ship eastward.

A farewell look was taken at the mysterious country and its Transient Lake.

Then the air-ship sailed away.

It is a long journey from the Andes to the Atlantic.

It seemed an eternity of jungle, stream, and forest of hideous marsh and barren plain ere the tossing waters of the stormy ocean were seen.

Then a course was shaped northward along the coast.

Stops were made briefly at Santos and Rio Janeiro. Then the South American coast was left behind.

On sailed the air-ship over the West India Islands toward the coast of Florida.

“Begorra, there’s no place loike the United States afther all,” declared Barney, “savin’ mebbe ould Oireland.”

“Huh!” exclaimed Pomp; “yo’ allus hab to place dat lily bit of an island befo’ eberyfing else.”

“Bejabers, an’ phwy shouldn’t I?” asked Barney, sharply; “ain’t it the truth, to be shure?”

“If dey grow such tings as yo’ dar, wild, I kain’t say I fink it am anyfing but a berry lily green spot on de face ob de yairth,” averred Pomp, solemnly.

Barney was tired in a moment. He saw the fun lurking in the corners of Pomp’s eyes.

He was all ready for a ruction and this assertion touched him off.

“So yez think it is only a little grand spot, eh?” asked the Celt, rolling up his sleeves. “Well, grane is not hurtful to the eyes, I’ve heard tell, loike the black yez get in Afriky.”

“Wha’ yo’ know ’bout Afriky?” exclaimed Pomp.

“What do yez know about Oireland?” spluttered Barney.

“All I knows ’bout it is jest wha’ yo’ hab tole me, an’ dat am enuff,” sniffed Pomp. “Wha’ yo’ got yo’ sleeves rolled up fo’?”

“Begorra, I don’t allow any mon to insult me or me native land,” said the Celt, hitching up his trousers; “here’s phwat backs me up.”

He shook a fist in Pomp’s face. The darky dodged, and the Celt made a biff at him. Then they closed in an exciting encounter. Long and hard it was, but as it would have been impossible to injure either one of their tough skins and hardy frames by any dint of such pounding and wrestling, they finally emerged from the encounter hardly the worse for it.

But the honor of each was satisfied, and their mania for wrestling as well.

In due course of time the Gulf of Mexico was crossed, and one day Captain Nicodemus sighted Key West.

The voyagers could not refrain from a jolly cheer at the sight of their native land.

Soon the air-ship was sailing over the great swamps of Okeechobee, and then swept over the great orange groves and plantations of the sandy state. Georgia, South and North Carolina followed.

Along the Atlantic coast the voyagers journeyed until finally the mouth of the Chesapeake came into view, and later the Potomac. Then they hung over the Capitol city and steered west for Readestown.

The great journey was ended.

The Transient Lake and the mysterious country had been visited and were now history in the minds of the aerial voyagers. They had also brought home some of the gold.

All were satisfied and this was enough. Captain Nicodemus embraced Frank gratefully for this, his last voyage. Then he returned to his home.

Frank Reade, Jr., Barney and Pomp are yet in Readestown. The young inventor is studying up new things which we may hear from at some future day.

The End