The Airplane Boys on the Wing

CHAPTER I : ON THE WAY BACK FROM THE GAME
"But the Bird boys won the prize of a silver cup!"

"What if they did? It was by a hair's breadth, Mr. Smarty!"

"And their monoplane was proven to be faster than the big biplane you built, Perc Carberry!"

"Oh! was it? Don't you be too sure of that, Larry!"

"Didn't it land on the summit of Old Thunder Top ahead of you and Sandy, in the race that afternoon? Tell me that!" and Larry Geohegan bristled up to the recognized bully of Bloomsbury, while a dozen fellows clustered around on the deck of the big power boat, listening eagerly to this war of words.

They were on their way home from a very exciting game of baseball that had been played at Cranford, across the lake. And after ten innings of hot work the nine from Bloomsbury had won. But not until they had changed pitchers, upon tying the score in the ninth, after coming up from behind.

Percy and Larry both wore the uniform of the home players, and there were others on the boat who also belonged to the team. In fact, the staunch vessel had been placed at the disposal of the baseball club for this day, by Commodore Elliott, the rich owner.

Larry had never been one of the adherents whom Percy could call upon to back him up when he tried conclusions with a hostile faction; in fact, Larry had always been an admirer of Frank Bird, who was recognized as the most persistent rival the bully had ever encountered in his whole career since coming to Bloomsbury.

Percy allowed a contemptuous expression to take possession of his face, and even shrugged his broad shoulders, after a nasty fashion he had, that often angered the one he was arguing with more than words could have done.

"Aw! rats!" he said, in a disagreeable, rasping voice. "Everybody knows that I'd won that same race only for trouble with my engine. Frank was lucky, just like he generally is when he goes in for anything. Look at him today, being called in to pitch in the tenth! We had 'em badly rattled, and they were on the toboggan sure. Yet Frank, the great hero, gets credit for winning that game. Didn't the Bloomsbury crowd cheer him to the echo, though, and want to ride him on their shoulders? Wow! it makes me sick, to see such toadyism!"

"What's all this big noise about, fellows? Didn't I hear my name mentioned?" asked a tall lad with a frank face and clear brown eyes, as he pushed forward.

It was Frank Bird himself, who had been talking with his cousin Andy, and several other fellows, in the bow of the launch, and by accident heard the voices that were raised in dispute.

Percy Carberry, known among his comrades simply as "Perc," did not flinch when he found himself face to face with the boy he detested so thoroughly. They had never as yet actually come to blows; but Perc believed that his muscular powers were far superior to those of his more slender rival, and just now he was in a particularly bitter frame of mind.

"Oh! so you're there, are you?" he sneered "I was just telling your good friend Larry here that I considered you a greatly overrated substitute pitcher; and that luck had as much to do with our winning that game today as anything you did."

Frank Bird laughed in his face.

"Sure," he declared, cheerily. "I was a mighty small factor in the victory, for I only played in one short inning. If I'd faced those hard hitters of Cranford nine times I reckon it'd be hard to tell what they'd have done to my poor inshoots and curves."

"But you held them in that inning, Frank, you know you did!" cried Larry.

"Mere accident, my boy. Happened to be the weak end of their batting list!" observed Frank, as if determined to agree with his enemy, and thus spike his guns.

"Is that so?" demanded "Elephant" Small, who did not happen to be on the nine, because of his customary slow ways. "Perhaps you'll be saying that dandy two-bagger you whanged out, that brought in the winning run, was also an accident?"

"Well, I must have just shut my eyes, and struck. I seem to remember hearing a sound like a shot, and then they all yelled to me to run; so I did, going on to second in time to see Peterkin gallop home," and Frank looked as sober as a judge as he said this. The others saw the joke, however, and, led by Larry, burst out into a laugh that made Perc and his loyal backers scowl.

"If that bingle was an accident, don't we wish we had a few more players who could shut their eyes and meet Frazer's terrible speed balls and curves in the same way!" one fellow exclaimed.

"So say we all of us!" another cried.

Perc realized that the majority on board the Siren were against him. But he was not given to taking water; even his enemies, and he had many in Bloomsbury, could hardly say that Perc was lacking in a certain kind of grit; while stubbornness he possessed in abundance.

So he just shut his white teeth hard together, and looked scowlingly around the bunch of fellows. And many of them felt a little chill when those cold gray eyes rested upon them; for they knew of old what happened when Perc Carberry made up his mind to mark a boy for future attention.

Frank still stood there by the side of the boat, smiling. Perhaps his very apparent unconcern served to make the other still more angry. There had been bad blood between these two lads for a long time, and more than once it threatened an eruption, which somehow or other had up to now been stayed.

Although some weeks had passed since the much-talked-of race between the rival aeroplanes, piloted by these two boys, in which Frank took his little craft up to the lofty summit of Old Thunder Top ahead of Perc in his biplane, as narrated in the first volume of this series, entitled "The Bird Boys; or, The Young Sky Pilot's First Air Voyage," the latter had never ceased to feel ugly over his defeat.

As usual he had what he considered a good excuse for his arriving second; but few persons ever knew how Perc and his helper Sandy had tried to injure Frank's airship when it was directly beneath them, by deliberately dropping a sand bag, taken along, singularly enough, as "ballast," but with this very idea in view.

"Seems to me you've gotten the big head ever since you happened to drop on that rocky plateau on top of the mountain just three little seconds ahead of me, Frank Bird!" he said, with a steely glitter in his eyes that those who knew him best understood to mean coming trouble.

"Oh! I hope not, Perc," replied the other, with a smile. "I give you my word my hat fits me just as comfortably as ever. It was a close race, and the one who got there first hadn't much to crow about, for a fact. We happened to be lucky not to have any trouble with our new little Kinkaid engine, that was all."

"Huh!" grunted his cousin Andy, shaking his head, and scowling at Perc in turn. "But we had plenty of other sorts of trouble, all the same, sand bags full of it, in fact. They just rained down on us; but then Frank knows how to check up his engine suddenly, and the storm passed by without any hurt!"

Some of the fellows, who happened to know what this sly reference on the part of the hotheaded Andy meant, began to chuckle. Of course such a thing would only serve to make Perc more angry. He chose to believe that they were all only trying to bait him.

Frank in particular came in for his dark looks. And Larry, who had once run in the same company as Perc, so that he knew his whims better than many others, took occasion to give Frank Bird a sly nudge in the side, as he whispered:

"Look out for him, Frank; he's getting near the danger point, sure!"

But Frank did not have to be warned. He had grown tired of warding off this ever threatening danger of a broil with Perc Carberry. Like his cousin Andy, the other had no father; and his wealthy mother had long since given up in despair the idea of controlling the headstrong lad. So that Perc had his way, whenever he wanted to do anything out of the ordinary.

Because Mrs. Carberry was one of his father's patients, and Dr. Bird esteemed her very highly, Frank had postponed the reckoning just as long as he could endure the insults of the bully. But he believed the last ditch had been reached, and was determined to no longer raise a hand to avert the threatening storm.

Perc had turned when Andy spoke, to flash a look in his direction. But it had no effect upon the other, who could be as reckless at times as the next one. Indeed, Frank often had to curb the impatience and daring of his chum.

"Oh! that's what sticks in your craw, does it, Andy Bird?" demanded Perc. "Just because Sandy happened to drop that ballast, thinking we might make better time if we lightened ship, you choose to make all sorts of nasty insinuations about us wanting to knock you out! Shows where your mind is. Another fellow wouldn't ever let such a fool notion get a grip on him. And you'd better put a reef in that tongue of yours, my boy, unless you want to have it get you into trouble."

Andy flared up at once, and would have replied; but Frank calmly stepped in between the two, as though he claimed first right.

"Neither of us have charged you with intentionally trying to disable our aeroplane by dropping that sand bag, Perc," he remarked quietly. "All we say is that it was a queer coincidence you wanted to get rid of your ballast just when we were walking up on you hand over fist, and about to pass under you, to take the lead. That's all!"

Again there was a low laugh from among the boys who stood around listening. To them it was a rich treat to see the recognized bully of Bloomsbury baited to his very face in this characteristic way; and they were enjoying it hugely.

"Well, let me tell you it ain't all, not by a jugful!" exclaimed Perc, his face taking on a purple hue, as it always did when he became enraged. "Both of you fellows have got to stop speaking about that sand bag dropping, or there's going to be a licking in store for you. See?" and he thrust his face close to that of Frank as he said this. Larry Geohegan fairly held his breath. "Now it's coming; don't I know the signs?" he whispered to the boy next him.

Frank continued to stand there, close to the side of the speeding launch. They were about half way across the deep lake at the time. Evening was coming on, for the sun had just reached the distant rugged horizon in the west.

"Do you refer to me when you say that, Perc?" he asked, with that same queer little smile on his face—a look that mystified the other, who could not understand what it meant.

"Yes, both you and that loud-mouthed cousin of yours. Just because luck favored you, and you won that blooming race by a head, you think I can't manage an aeroplane as well as you. Huh! perhaps you don't know that I'm going to take my machine with me when I go down to the cocoa plantation we own along the Amazon, and use it exploring where a white man has seldom been seen. You can just stay here and grow up with the country, while I'm doing great stunts. But as long as I stay here I'm going to stop this talk about trickery and low-down dodges. You're responsible for most of it, Frank Bird. I warn you what's coming to you." "Perhaps," said Frank, pleasantly, "you would be kind enough to tell me also when this awful punishment is going to fall on my poor devoted neck?"

"Any time, hang you! Right now, if you say another word!" roared Perc, doubling up his fists, and making ready for one of his well known and feared bull rushes, that had brought him a speedy victory many a time.

"So? That's comforting; and with all these good fellows around to see how you wipe up the deck with me. Suppose you begin the swabbing act, Perc!" and Frank pretended to throw himself in a position of defense.

The other gave utterance to a hoarse cry of rage, and lowering his head after the manner of a bull, jumped forward. But the agile Frank simply stepped aside; and unable to check himself in time, Perc Carberry shot over the side of the power boat, disappearing in the clear waters of Sunrise Lake with a great splash.

"Oh!" shouted his crony, Sandy Hollingshead, standing there as if petrified; "and Perc can't swim a single stroke, either!"

CHAPTER II : FRANK'S WAY
"My goodness, what a splash!"

"Served him right, that's what!"

"He's gone under, fellows! Dove just like a big frog!"

"Stop the boat! He'll drown!"

Half a dozen were shouting in unison, as the boys crowded to the side over which the bully had pitched when Frank avoided his forward rush.

But Frank heard only that startled exclamation from Sandy Hollingshead:

"Perc can't swim a single stroke, either!"

With Frank Bird to think was to act. The two things were almost synonymous in his mind. Forgotten was the fact that the imperiled lad had been endeavoring to strike him in the face at the time of his submersion in the waters of Sunrise Lake.

Not a single word did he utter, but throwing off his coat, he made a leap over the side of the boat, already slowing up as the power was cut off.

"Frank's gone back after him!" cried one.

"And he'll get him, too," another hastened to say; for they understood that when the leader of the team known as the "Bird boys" attempted anything he usually got there, as some of them said "with both feet."

Meanwhile Frank was swimming with all his might toward the spot in the foamy wake of the boat, where he knew the unfortunate Perc must be battling for his life.

It seems strange that occasionally a boy may be found who has never taken the trouble to learn how to swim. In the country this is a rare occurrence; which would make the neglect of such an athletic fellow as Perc seem more remarkable.

He was threshing about in the deep water like a cat that has fallen overboard; and managing to keep partly afloat after a fashion; though it would have been all over with him long ere the power boat could be turned around and arrive at the spot where he struggled, gasping for breath, and sucking in much water.

Frank was wise enough to understand that it is always desirable to approach a drowning person from the rear, so that a grip may be taken before the would-be rescuer's presence is discovered. Once let those frenzied fingers clutch hold of him, and the chances of a double tragedy would be good.

So Frank was keenly on the watch as he swam toward the splashing and gurgling that announced Perc Carberry's fight for his life.

He could see him by now, and never would Frank be apt to forget the look of absolute terror he discovered upon the agonized face of the bully. Perc had detected the presence of some one near by, and was trying to shout, as well as stretch his appealing hands out, though not with much success.

He actually went under while Frank looked; and the heart of the would-be rescuer almost stood still with a terrible fear that that was the end.

But he kept on, and in another moment a head once more bobbed up, with Perc threshing the water frantically. Once he had gone down. According to what most people said, he would possibly vanish twice more, and after that never rise again.

If anything was to be done, there was no time for delay. Frank was within ten feet of the struggling figure when it came up. He immediately dove, and managed to rise to the surface behind Perc. Then, just as the other was floundering beneath the surface of the agitated water again, Frank caught hold of his sweater close to his neck, and held on with might and main.

He had a serious job of it, for the half-drowned lad made a desperate attempt to turn around, doubtless with the intention of throwing his arms around his rescuer. This was just what Frank was desirous of avoiding. He simply wanted to keep the head of Perc above water until the boat could come and willing hands be stretched down to relieve him of his burden.

So he kept treading water and fighting Perc off as best he was able. It was no easy task, since he still had his baseball shoes on; and swimming in one's clothes is always a difficult proposition. But Frank knew no such word as fail and continued to strive, keeping one eye on Perc and the other on the approaching power boat.

"Steady now, Perc!" he kept saying, again and again, trying to instill some sense in the head of the frantic boy, who still believed he must be going down again. "Keep your breath in your lungs and you'll float! Don't kick so; I'm going to hold you up till the boys come. It's all right, Perc; you're safe!"

All the same Frank was mighty well pleased when the launch did swing close alongside and half a dozen hands reached out to clutch hold of them both.

"Perc first, fellows!" he said, with a half laugh. "I can crawl in myself, I guess." But they would not hear of it, so willing hands lifted him up as soon as the other dripping figure had been deposited in the bottom of the boat.

Frank made light of the adventure, after his usual style.

"Oh, come, let up on that!" he remarked, when some of the fellows were patting him on the back and calling him a hero and all such things that were particularly disagreeable to Frank. "It was just a cinch to me, you know. I'm half a water spaniel, anyway. Besides, if it hadn't been for the way I riled him, Perc wouldn't have fallen overboard. Drop it, please."

By the time the boat reached the landing near the dock where the lake steamer touched, Perc seemed to have discharged his cargo of water, swallowed unintentionally.

He made his appearance, with several cronies clustered about him. Frank was not the one to hold a grudge. Besides, he had come out of the affair with flying colors and had nothing to regret. So he strode up to Perc at once, holding out his hand.

Every boy on board crowded around, eager to see how the bully would behave, for they knew his natural disposition and wondered whether any sort of miracle had been wrought in his disposition because of his recent submersion.

"I hope you're feeling all right now, Perc," Frank said, pleasantly. "I wanted to ask your pardon for treating you so roughly; but knowing you couldn't swim, I was afraid that if you closed with me we'd both go down."

"But you struck me once right in the face, you coward!" exclaimed the other, as he put his still trembling hand up to where a bruise of some sort could be seen.

"Yes, I admit it," returned Frank, quickly; "and that was what I wanted to apologize for. You grabbed me and it was the only way I could break your hold. I've been told by life savers that often they have to strike a man and knock him senseless to save themselves from being dragged down. You must understand that it was no time to be particular. I had to save myself in order to help you!"

The other stared hard at him. Evidently Perc had not yet entirely recovered after his close call. At any rate it was positive that he could not understand how he actually owed his very life to the speedy action of this boy whom he hated so bitterly.

They saw him shake his head, much as a dog might that is worrying a rat.

"Well, you only undid your own dirty work. You pushed me in and then you got cold feet. For fear that I'd drown and you'd be hung you jumped in to do your usual grandstand act of hero! Didn't I hear these softies calling you that right now? No, I don't want to touch your hand. Keep your friendship for those who can appreciate it. There's a long account between us that's going to be settled some fine day."

And with these ungrateful words Perc Carberry strode off the boat, surrounded by his cronies, who were doubtless pleased with the course of things.

"Well, did you ever hear of such base ingratitude in all your born days?" exclaimed Larry Geohegan, making a gesture of supreme disgust.

"And to think of the skunk saying Frank pushed him in!" echoed Elephant, "when he actually risked his life to save the cur. Ain't I glad now I didn't carry out my first impulse and jump after Perc, even before Frank went. Why, maybe he'd have even said I tried to drown him!"

The idea of that proverbial slow coach of an Elephant ever doing anything on the spur of the moment was really too much for the rest of the boys and a general roar went up. "Don't bother your heads about me, fellows," remarked Frank, quietly, when the laughter had ceased again. "That was just about the kind of treatment I should have expected to get from Perc Carberry. Still, I'm not sorry I did it. Life would seem very tame without that schemer around to try and liven things up for me. But I hardly expected him to accuse me of pushing him in when all I did was to step aside and avoid a blow at his hands. Forget it, please."

He walked off with his cousin Andy, who had been boiling over at the time the rescued Perc made his astonishing accusation.

"Wouldn't that jar you some now?" remarked Andy, after his customary fashion.

"I suppose you're referring to the way Perc turned on me after I went and got my baseball suit wet just to give him a helping hand?" laughed Frank, good naturedly. "Oh, I don't bear any malice. Perhaps he was still a little stunned by that knock I gave him. But I thought he was going to get his arms around my neck, you see, and then it would be all up with us both. It worked, too, for he was as limp as a dishrag from that time on. Remember it, Andy, in case you ever jump over after Perc."

"Me after that snake? Why, hang it, I'd see him in Guinea before I'd ever lift a hand to save him! I tell you I'd—I'd—" stammered the indignant Andy.

"I don't believe it of you," declared his cousin, quickly. "You may think you'd stand by and see him drown, but that's all gammon. I know you too well to believe you're half as vindictive as you try to make out. But did you hear what he said about going down there to South America, visiting a plantation his mother partly owns and taking his biplane along with him?"

Andy was all excitement now.

"Sure I did," he said. "And ten to one he learned somehow that we thought of going down in that region for another purpose. It would be just like Perc and that sneak of a Sandy Hollingshead to try and beat us out. That fellow wouldn't mind a trip to the other end of the world if he thought he could get your goat, Frank. He hates you like poison. Pity you didn't feel a cramp just when you were swimming to him—not enough to endanger your own life, you see, but sort of make you stop short."

"Shame on you, Andy," remarked Frank. "I hope I'll always carry myself so that I won't be afraid to look at myself in a glass. But what do you know about that place—didn't he call it a cocoa plantation or something of the kind?"

"Yes," replied the other moodily; "I was told that his mother owned two-thirds of some such place along the Amazon or somewhere down there. But let them go. It's a tremendous big country and there isn't the least danger that we'll ever run into them, if we should decide to take a run down."

"Still," observed the taller lad, thoughtfully, "you never can know. I've heard travelers say that sometimes the world seems to be very small; when you meet your next door neighbor on the top of some Swiss mountain. Perc may know nothing about your plans and this is perhaps only a coincidence, as they say. Since he has had such poor luck getting to the top of our mountains around here he wants to try his hand on those poor South American Andes."

Andy's father had been a professor in one of the colleges, who, having taken up aeronautics, had made many balloon voyages in quest of scientific information, so that his name had become quite famous. Then, about a year before, he had been lost when attempting to solve the air currents on the Panama Isthmus, where the government had thirty thousand laborers digging the big ditch.

Nothing had ever been heard of the professor from the day he started from the Atlantic side of the isthmus, intending to cross the mountains and land on the Pacific beach. And it was becoming a positive mania in the mind of Andy, who lived with his guardian, Colonel Josiah Whympers, to some day go down there and follow in the track of his lost father, in the hope of discovering his sad fate.

It was with this idea in mind that he had united his forces with Frank's inventive genius and helped build the monoplane with which they had won the race to the top of the neighboring mountain, during Old Home Week at Bloomsbury.

And every day he was thinking more and more of what strange things the future might have in store for him, if he ever started on that exploring venture.

CHAPTER III : SOMETHING ABOUT THE BIRD BOYS
"How about coming over tonight?" asked Frank, as the boys halted at the gate of Dr. Bird's place, where Andy had gone to get his wheel, since he lived some little distance away.

"I'd like to first rate, Frank, because there are some things I want to talk over with you. But I promised Colonel Josiah to get at his books tonight and straighten them out. It'll take me all evening, I reckon."

"Oh, well," remarked Frank, "see you in the morning anyway. This breeze will have worn itself out by then, perhaps, and if we feel like it we can take a little trip somewhere in the 'Bug,' as you like to call our dandy little aeroplane."

"I hope so," replied Andy, eagerly. "It's been some days now since we were up, and I'm more than curious to find out if that new arrangement of yours is going to help us any in getting a quick start."

"Does the colonel still persist in having old Shea sleep outside the shed?" asked the other, as Andy pushed in to get his wheel out from under a side porch, where he had thrust it before starting off to the baseball game.

"Sure," came the reply. "When Colonel Josiah once starts on a thing it would take an earthquake to stop him. I tried to tell him that there was no danger of our monoplane being injured now that those two men who robbed the jewelry store were locked up at police headquarters, waiting for some formality to start them on the road to a ten-year sentence; but he only shook his head and said Shea had nothing else to do and might as well be earning his salt."

The incident to which Andy referred was related at length in the preceding volume of this series, "The Bird Boys; or, The Young Sky Pilots' First Air Voyage," and had created a ten days' sensation in the quiet little lake town of Bloomsbury.

Two rogues had robbed the extensive jewelry establishment of Mr. Leffingwell and carried off the loot in a couple of suit cases taken from the store. Unable to get clear away on account of a quick chase, they had hidden in the vicinity of the town. One of them, named Jules, had been an aviator at some time in his near past over in France, and learning that the Bird boys had built a monoplane, which was even then ready for a flight, they had attempted to steal the same, with the intention of giving their pursuers, who were hunting the woods for them, the laugh.

But their well laid plans were spoiled through the vigilance of the Bird boys and the quick wit of Frank in particular. The consequence was that both men were eventually captured by Chief Waller and his officers and still languished in the town lock-up, awaiting the day of trial.

"Oh, well!" laughed Frank, as his cousin wheeled his bike out to the front gate, where he could mount better, "it makes mighty little difference, because, from what I've seen of Shea, I imagine he sleeps on his post. I'm glad we didn't let him inside, because, like all Irishmen, he is fond of his pipe and might have set fire to the shed. It's dangerous smoking where there's a lot of gasoline about."

"Of course we've got that Perc Carberry and his mean crony, Sandy Hollingshead, to consider. They tried to injure our machine once and might again, especially after what happened today," said Andy, throwing one leg over his saddle and standing there a minute.

"Oh, I guess not, Andy. They understand that we're keeping tabs of that hangar, with its precious contents. Besides, they've got their hands full of other matters, if what Perc said about that big trip to the Amazon country is true."

The other sighed.

"I only wish I was as sure of going down there as Perc seems to be," he observed. "I don't know how it is, but something queer seems to be drawing me that way. Day and night I have pictures rising in my mind. I've read every scrap concerning the Isthmus and northern coast of South America, until I guess I'm as well posted on such things as one who had been there."

"Yes," said Frank, softly, "and I'm afraid you let your mind dwell too much on that subject, old chum. It's more than a year now since your father disappeared. And the chances of your ever finding what became of him are like searching for a lost diamond in the sand of the seashore. It's affecting your mind, Andy. You look all fagged out. I wish you could cheer up and be something like your old self."

But the other only shook his head sadly.

"I don't believe I ever can, Frank, until I've had my chance to go down there and make a good try to find all that is left of my poor father. Just as you say, it seems almost silly to think that I could ever succeed, but no matter, I've got it arranged in my mind and the colonel is coming around slowly."

"Well," Frank hastened to declare, "you know if it ever does get to the point that you do go down to make that search, I'm with you. My father would never throw any obstacle in the way, I'm dead sure. And Andy, of course we'd take our aeroplane along. Think how many trips we could make in her over country that no one could ever penetrate on foot."

Andy was too full for further words. He simply turned and squeezed the hand of his cousin; but the look of affection which he gave Frank told what was in his mind just then.

Frank watched him go spinning along the road and then with a sigh turned into the house.

The day had been replete with excitement for him. First there was the keenly contested game with their rivals across the lake and a tie in the ninth inning, which gave the Bloomsbury boys a chance to win out in the tenth. His pitching had held the enemy safe, and in their half of the inning Frank had made the hit that brought the game to a conclusion. As a rule the home club took the last chance at the bat, but the Cranford manager had chosen differently on this occasion, for some reason of his own, and with disastrous results.

Then, on the way home, had come that little diversion aboard the launch, when his old enemy, Perc Carberry, in attempting to strike him, had miscalculated and gone plunging into the lake, himself being unable to swim.

Frank had nothing to regret in connection with his leap after the struggling lad and his subsequent saving of Perc. True, the latter chose to crush down the natural spirit of gratitude that should have made him accept the hand Frank offered later. But Frank felt that he could afford to smile at such an exhibition of a small nature.

At the supper table his father and Janet, his sister, just home from boarding school a couple of weeks back, plied him with questions concerning the game. Of course, the girl had been present and had seen her brother carry off the honors on the diamond; but there were lots of things she wanted explained.

And before Frank knew it he was asked point blank what had happened on the way across the lake, for Janet had been aboard another boat, it seemed.

"Marjorie Lee told me she heard that you jumped overboard to save some one, she didn't just know who?" was what Janet said, and the good doctor pricked up his ears as he looked inquiringly toward the boy of whom he was so proud.

Frank turned red and then laughed.

"Oh, pshaw!" he said. "I had hoped that would be kept quiet. But some of the fellows like to talk too much."

"Who was it you jumped over after? They said you held him up until the boat got around—that he could not swim a stroke, and must surely have drowned only for your prompt action. It couldn't have been Cousin Andy, because he can swim nearly as well as you. Tell us, Frank," Janet persisted.

So Frank found himself compelled to relate the whole circumstance. In his usual generous manner he tried to gloss over the conduct of Perc and spoke as though the other had tumbled overboard during a little boyish roughhouse business; but Janet knew of the enmity between the pair, and she could read between the lines.

Frank spent a couple of hours after supper in poring over a book Andy had loaned him. And it might easily be assumed that it had to do with the birds, animals, fauna and inhabitants of that great country lying north of the equator, down in Central and South America.

It was about nine o'clock when his father called to him. The doctor had just come in from a few last visits and looked anxious.

"Frank, I'm in a peck of trouble," he said, with a whimsical smile, "and I wish you could help me out, though I dislike putting you to so much trouble."

"Oh, don't mind that, dad, one little bit; you know I'm only too glad to be of any assistance to you. What's gone wrong now? Machine laid off again and garage closed? But you won't need it till nine tomorrow, will you?"

There was a world of affection in the very way Frank used that word "dad." It might seem disrespectful coming from the lips of many boys, but to the ears of the good doctor it was as sweetest music.

"That's the trouble, Frank. I do need some means of getting around tonight the worst kind. Fact is the car broke down just as I got it in the yard. Same old trouble, and will take an hour to fix it up. And all at once it dawned on me that I had forgotten to take the medicine out to Farmer Lovejoy, which I surely promised tonight. It lies under the seat of the machine. Slipped my mind entirely when I was out. And Frank, there may be a serious turn to that child's sickness unless that medicine gets there within the next hour or so."

"Don't say another word, dad," declared Frank, jumping up and getting his cap. "My wheel is in fine shape and with a good lantern I can make the run in a jiffy. Only too glad to be able to help out. The packet is under the seat in the car and you left that in the side yard? All right, I'm off!"

CHAPTER IV : A STARTLING DISCOVERY
It did not take Frank many minutes to get started on his little trip.

As he had said, his wheel was in good shape, with neither tire needing any pumping up. And even his acetylene headlight had only to be attached, which task took but a short time.

"I declare!" he exclaimed, as he rested his wheel against the gate and turned back, "that would have been a rough joke on me if I'd gone spinning off and only remembered after I'd almost got there that I forgot to take the package of medicine out of dad's little runabout. So much for having my brain full of that wonderful scheme of Andy's."

He found the medicine, and as the packet turned out to be small enough to be stowed away in one of his coat pockets, Frank so disposed of it. Then wheeling his machine out into the road he took a last look at the lantern, to see that the water might not be dripping on the carbide too rapidly to combine the greatest efficiency. After that he swung into the saddle, starting off with the perfect freedom that proclaims the rider a master of his wheel.

Once he passed out of town Frank made good progress. He had a ride of several miles before him, ere he could expect to reach the farmhouse of Jason Lovejoy, one of his father's oldest customers and friends.

There was no help from the moon, because the sky had clouded up and screened the young queen of the skies. But Frank needed no other light than the brilliant glow that spread out along the road ahead of him coming from his lamp.

It happened that he passed the home of Colonel Josiah Whympers, the retired and lame traveler, in whose care Andy had been left by the will which his father had made before starting on what had proven his last air voyage.

"Guess Andy's gone to bed," he mused, as he saw the house wrapped in darkness, for it was now after half past nine.

Frank cast a glance back toward the big field where the shed stood in which the great little monoplane, in which they had won their victory during Old Home Week, was stored. But he could just barely make it out, owing to the distance and the faint light of the moon coming through the clouds.

Naturally the hearts of both lads went out toward the gallant aircraft which had answered every call made upon it for speed and endurance. It was equipped with an engine of the latest make, weighing only a third as much as the average aeroplane motor and a triumph of modern scientific discovery. Since the Bird boys had constructed that monoplane themselves, after patterns obtained elsewhere, surely they had reason to be proud of their work and the gallant victory which had come to them.

Frank pedaled on, thinking nothing of the trip. He was accustomed to being abroad at night with his wheel, and, indeed, had taken many a twenty-mile run by the light of his lamp alone.

What was there to fear? Bloomsbury was a peaceful community. Rarely did anything occur to indicate that a spirit of lawlessness was abroad. Occasionally the police had some trouble with wandering tramps, but Chief Waller's strong point seemed to lie in that direction, and as a rule hoboes gave Bloomsbury a wide berth. The word had gone out that they made stragglers work when caught there, and nothing could be more horrible in the eyes of these "Wandering Willies."

After passing Andy's home it was not more than twelve minutes before Frank found himself approaching the quiet farmhouse where he was to leave the medicine.

The doctor had told him to ask a number of questions with regard to the little sufferer, and Frank was well enough up in medicine to know what to say when he learned how matters were going.

A big watchdog boomed his hoarse bark upon the night air, as Frank dropped off his wheel at the gate where the mail box was fastened.

"Hello, Kaiser! Good dog! Don't you know me, old fellow? Come here and be friends, Kaiser! It's all right! I'm coming in!"

Frank knew how to use a wheedling voice that a dog instantly recognized as belonging to a friend. Besides, instinct doubtless told Kaiser that any one who had evil intentions would come sneaking around and not in this bold fashion.

At any rate, the big mastiff began to wag his tail, and though he still barked, it was by way of a welcome now. Frank fearlessly opened the gate and walked in. The guardian of the farm came up to him, sniffing, and Frank, without hesitation, rubbed his hand over the shaggy head of Kaiser.

So side by side they advanced to the house. Already a door had opened, showing Farmer Lovejoy with a lamp in his hand. Evidently they had been anxiously waiting for the coming of the good doctor, and were possibly beginning to worry because he had failed as yet to show up with the medicine he had promised.

"It's you, Frank, is it?" asked the farmer, as the lad drew near the stoop.

"Yes, sir," replied the boy, cheerily. "His machine broke down and I had to come on my wheel. But father said it was very important that you have this medicine tonight. He expects great things of it by morning."

"Well," said Farmer Lovejoy, warmly, "that was right nice of you to come all this way on your wheel, Frank. But I guess it's on'y what we'd expect from Doc Bird's boy. I saw ye make that trip up to the top of the mountain in your airship, Frank. I tell ye it was wuth seein'! Won't you come in? The missus'd like to see ye."

"Why, yes, I will; because dad asked me to explain something to you and also get some information about Sue. A few minutes will make little difference," Frank said.

But, although he did not suspect it just then, even seconds came very near being of the greatest importance.

Perhaps he spent all of ten minutes in the Lovejoy home and in that time learned what his father wished to know. The old farmer came to the door with him, shaking hands warmly.

"Once again I say I'm obliged to ye, Frank," he remarked, with feeling, "for comin' away out here to fetch the medicine. It may be the means of savin' our gal to us, who knows? But I've got faith in your father. If anybody kin fetch our Sue around he will. Good night, lad. Kaiser, mind your manners. This is one of the best friends we've got."

"Oh, that's all right, sir," declared Frank, quickly, as he patted the shaggy head of the big mastiff. "We understand each other, don't we, old boy? He knew my voice, because a dog never forgets a friend, and I've played with him many the time. Good night, Mr. Lovejoy. Keep up your spirits. Dad says Sue is going to get over this all right in a little time."

Once again on the road he turned his face toward home. After all, this six or seven-mile run was only a good touch of exercise, and he would sleep all the sounder on account of it. Besides, Frank loved nothing better than to do something for the parent who all his life had been so indulgent to him.

As he pedaled along, keeping his eyes well ahead, so as to glimpse any vehicle that might loom up in his path, he was thinking of what Andy had in mind. While the project was as yet rather uncertain, Frank seemed to feel that his cousin could never be wholly satisfied that he had done his duty by his father until he had spent some time down on the Isthmus trying to get some traces of the lost aeronaut.

"I reckon I ought to know something of Andy's persistence," he said to himself, with a chuckle. "And now that he's got this bee in his bonnet there'll be no peace until he tries the scheme out. Sure I'm with him from the word go. It makes me shiver all over with expectation just to think of what glorious times we two chums might have—hello! there's something ahead, and I'd better slow up!"

It proved to be a farm wagon, pulled by two tired nags, and headed for home, after a day in the town market. The driver was asleep on the seat, leaving to the sagacity of his animals the successful navigation of the road.

Perhaps some movement of the horses or else the bright light of the acetylene headlight falling on his face aroused the man, for he sat up as Frank was about passing.

"Hello! is that you, Frank Bird?" he asked, leaning forward to look closer at the rider of the bicycle.

"Sure; just been up to your neighbor's, Lovejoy's, with some medicine for his Sue," returned the boy, recognizing the farmer.

"How is the gal gettin' on?" called the other, over the canvas top of his seat.

"Fine. No danger, dad says!" answered Frank.

"That's good!" he heard the sympathetic neighbor remark, as he moved on.

Five minutes later and Frank once more found himself approaching the Whympers place. As before, the house was in complete darkness, as if the inmates were long since abed. Frank knew that the old man kept early hours, seldom sitting up, for he read much during the day, having nothing else to look after.

Then, as was only natural, the eyes of the bicycle boy turned once again with more or less affection toward the quarter where he could just dimly make out the long, squat shed out in the field, in which the precious monoplane was stored.

As he did so Frank uttered an exclamation of surprise.

"Why, there's a light over by the hangar!" he burst out. "Now, what under the sun do you suppose that old fool of a Shea can be doing? Oh, my! Look at the flame jump up! Why, as sure as you live I believe the shed's afire! And I can see the figure of a man moving about. This is no accident, but something worse! And it looks as if the little 'Bug' might be going up in smoke in a jiffy unless I can sprawl over the fence here and get on the spot mighty quick!"

CHAPTER V : A WARM FIVE MINUTES
"Fire! Fire!"

So Frank shouted, even as he jumped over the fence, and made a bee line for the center of the big field, where the shed lay in which the precious monoplane was stored.

He had hastily leaned his bicycle against the fence as he made the plunge. Nor did he cease to let out constant yells while running across the open as fast as his agile legs could carry him. Twice he tripped over some object and nearly fell, only to recover himself and speed on.

As he ran he kept his eyes upon the low building beyond. In this manner he plainly saw the stooping figure of a man or boy making off in a roundabout way so as to avoid him.

Frank's heart was burning with indignation because of this dastardly attempt to ruin the gallant little airship that had so nobly stood all tests and proven itself a splendid piece of workmanship.

"Oh, the contemptible coward! I'd just like to chase after him and get my hands on him once!" was the thought that passed through his brain.

But he knew he could not. The scoundrel, no matter who it was, must be allowed to escape in order that he turn his attention to the burning shed and try to save the airship from destruction. Once the fire got inside, there was enough of the dangerous gasoline about to insure the speedy burning of the whole flimsy fabric, all but the motor itself.

So Frank kept headed straight for the hangar, trying to shut out the sight of that crouching, fleeing figure. He continued to lift his sturdy young voice in repeated shouts:

"Fire! Fire!"

Those in the house must hear; yes, and the neighbors, too. He might not be able to master the flames alone and single handed, and would need help. Besides, it was only right that Andy, being part owner in the monoplane, should be made aware of its sudden peril.

As he thus drew near the low building he saw that the fire had already gained considerable headway, just as if the incendiary might have used kerosene or some other inflammable fluid, to hasten matters.

Frank's heart grew cold as ice as he contemplated the rapidity with which those hungry flames were crawling up the dry boards that constituted the side of the shed.

But he did not lose his head in this sudden crisis. It was characteristic of Frank Bird that, no matter what the emergency, he was always cool enough to think out the proper thing to be done or else jump at it through instinct.

And Frank had foreseen just some such possible need as this. He even kept several buckets of moist sand handy, where it could be snatched up at a second's warning, knowing that most fires can be smothered, when quenching them with water is out of the question.

"The buckets!" he gasped, as he arrived close to the building, one part of which was now fairly covered with the creeping tongues of ruddy fire. "I must use them on it!"

He had to turn the corner of the shed to get to where they stood. And as he did so he ran plump into a figure that was coming toward him. Just in time did Frank dodge a big fist that shot out. And in that second he recognized in the other Shea, the Irishman who had been hired to keep watch of the shed.

"Hold on, Shea!" shouted Frank. "It's me, Frank Bird. Somebody has set fire to the shed! Grab up a bucket of sand and carry it around here. We can put it out yet if we're busy!"

Shea had evidently only been aroused from a sound sleep by the approaching cries of the boy and was still in a daze. He had discovered the fire, and hearing Frank running toward him, supposed that this must be the one who had done the evil deed.

But he had sense enough to do as he was told now, snatching up one of the sand buckets and following the boy. Frank immediately commenced fighting the flames with a vim. He slapped the wet sand at the creeping fire, and wherever it struck there seemed to come a quick abatement of the conflagration. But it was by this time so extended that as fast as he succeeded in knocking it out in one place it cropped up afresh somewhere else.

His ammunition would not last if this kept up.

"Get busy, Shea!" he cried. "Find something and slap at the fire for all you're worth! Fight it, man, fight it!"

As Frank happened to turn his head to learn what the other was doing he saw something that made very little impression on his mind just then, but which had considerable bearing on the matter later.

A light was speeding along the road, heading away from town, and Frank realized that the firebug had seized upon his convenient wheel and was making his escape.

Later on he might figure out the meaning of this movement. Just then he really had no time to give it a thought, no matter if a dozen wheels were concerned. The fire demanded every atom of his attention.

Shea did get busy. Once he became stirred up, and he proved a valuable helper. He went for the flames tooth and nail, smothered them with his coat, regardless of consequences, after he had slipped that article of wearing apparel off; kicked and tore and fought until it became evident that between them they were certainly making a decided impression on the threatening conflagration.

All this while it seemed to Frank that his heart was in his throat. Not so much because he feared that they would fail to gain the mastery over the fire as that some spark might find ingress to the shed and happen to alight upon a can of the dangerous gasoline.

If such a thing occurred he knew that it would be all over. The hangar must be completely destroyed and, of course, their little darling airship would share in its fate.

So, even though he saw the end of the conflagration in sight, Frank knew he had no reason to breathe easily until every spark had been trampled under foot.

By now he was conscious of loud shouts coming from points near at hand and realized that doubtless Andy as well as others had been awakened by the racket and were coming on the run to assist. Had the safety of the airship depended on their reaching the shed in time, though, its chances would have been next to nothing.

Frank was just stamping on what seemed to be the very last vestige of the fire when Andy came galloping to his side.

"W-what's all this mean, Frank? Where in the wide world did you come from, and who set our hangar afire?" he gasped, almost winded from his exertions, for he had dressed in about a minute, despite his trembling fingers, and was barefooted even then.

"Don't know who did it, but he ran off on my wheel a few minutes ago. I was on the way home—carrying medicine to Susie Lovejoy. Saw flames and gave alarm. Got here on the jump and we managed to get the better of it. But it was a close shave, all right, I tell you, Andy!"

Frank himself had no breath to spare, nor could it be wondered at, considering the recent valiant fight which he had made against big odds.

"So the ornery skunks did try to burn us out, after all!" burst forth the other part owner of the monoplane, bitterly. "Say, where was Shea all this time? What use was he as a watchman?"

"He helped me good and hard at any rate. Only for Shea I'd never have got the better of it, I'm afraid," said Frank, always ready to cover up any little failing on the part of another, though never hesitating to denounce his own shortcomings.

"But just to think of the meanness of it all," continued Andy, shaking his head in the aggressive way he had. "That Perc Carberry ought to be shut up behind bars, that's my opinion straight from the shoulder, and if I could only find out for sure that he was in this I'd get Colonel Josiah to prosecute him to the limit."

"But we have no proof that it was Perc," remarked Frank. "The fellow who stole my wheel went off along the road away from town. And he went licketty split, too, as if he had business over in Shelby or Newtown. Perhaps it was only a hobo. He may have started the fire by accident, and was trying to put it out when I saw him first. Then, when I shouted, of course, he had to scoot."

"What's this?" demanded Andy, kicking some object, and then seizing hold of his foot, for he had forgotten that he had no shoes on.

Frank uttered a cry and picked it up.

"Look here, don't you recognize this?" he asked, as he held a can up.

It was Andy's turn to give vent to a low exclamation.

"Why, it's our kerosene can, Frank!" he said.

"That's what I thought. And it is kept on a bench just outside the kitchen door, isn't it?" demanded the other, quickly.

"That's a fact. And neither of us ever brought it here. Shea, did you ever see this oil can before?" and Andy dangled it before the eyes of the watchman who had slept on his post.

"I niver did the same, sor," replied the man, as he surveyed the can.

"Then that settles it, Frank. The mean skunk grabbed that can and fetched it over here to spray the wall of the shed with oil and making the fire jump."

"True as you live," said the other. "Do you know, I thought I smelled burning kerosene. And that was why the flames kept crawling up everywhere so fast. Well, it was a good job that we saved the place. And ain't I glad I didn't wait just five minutes longer at Lovejoy's place. Nothing could have helped then, and we'd just have to build another airship. But here comes the colonel stumping along, Andy!"

CHAPTER VI : IN SEARCH OF A CLUE
"Heigho! what's all this fuss and feathers about?" demanded the old retired traveler, as he came limping along, with his crutch and cane.

Several neighbors accompanied him, having been aroused by the clamor.

"Same old story, sir," remarked the disgusted Andy, still clutching his bruised toe tenderly. "They've been trying to beat us one way, if they couldn't another."

Frank gave him a nudge.

"Be careful what you say, Andy," he remarked. "There is no proof as yet that any one we knew had a hand in this business. You may get in trouble if you mention names offhand. Go slow now. We'll find out the truth later on, perhaps."

So Andy, taking heed, managed to tell what had happened without directly accusing any one. Nevertheless, it was not difficult for those who listened to guess where his suspicions lay. And perhaps they thought, after all that had occurred in the past, with the hand of Perc Carberry moving the pieces on the chessboard, that Andy was justified in believing as he did.

After a while the excitement died away. The boys had opened the shed and made sure that no lingering spark remained to threaten their beloved little aeroplane with destruction. But it was all right and they feasted their eyes on it, as if they never before realized how precious it had become.

"Getting to be a regular thing, seems to me, these night alarms, boys," remarked one of the neighbors, for not long before they had been aroused in the middle of the night when the two jewelry thieves tried to steal the aeroplane and were baffled in their design by the two boys, sleeping at the time in the shed, so as to guard their flying machine.

"If one watchman ain't enough I'll get three—half a dozen if necessary," declared Colonel Josiah, as he glared at the offending Shea and pounded on the turf with his heavy cane. "But these lads are going to be protected, if it takes my last dollar. I'll get a Gatling gun and train it here, so we can blow the rascals to smithereens if they try such a dastardly job again."

But everybody knew that the genial old colonel did considerable talking and blustering, but was harmless withal.

Shea promised to remain awake the balance of the night. He even went to the house and armed himself with a big horse pistol that the colonel owned and which had many a story connected with its keeping company with the traveler in foreign lands.

"Huh! I've got half a notion to camp right here again, like we did that other time, Frank," said Andy, before they locked the wide doors of the shed. "Here's my cot and blankets, you see, just as I left 'em."

"No need of that, Andy," returned his chum, smiling. "After all this rumpus you couldn't hire that fellow to come back here tonight. He may be ten miles away by now. Wonder if that's the last I'll see of my wheel?"

"Now," continued Andy, "if you're addressing that to me I'd like to prophesy that you'll find the bike somewhere off the road a mile or two away, where the fellow pitched it when he concluded to make a sneak back to town."

"There you go, barking up that same tree again. I never saw such a positive fellow as you are," declared the other, smiling. "Your name ought to be Thomas, for you seem to doubt everything that you can't just understand."

"Well, if not Perc, who, then?" demanded Andy, aggressively.

"I confess that I don't know at this minute," admitted Frank. "But I hope to discover the truth in some way. Remember how that other time, when some one tried to injure us by sneaking in here and cutting the canvas wings of our monoplane all to flinders, I picked up a playing card and we afterwards traced it to the owner?

"Yes," cried the other, instantly, "and wasn't that party Perc Carberry all right?"

"It sure was," laughed Frank. "But forget this thing for now. Perhaps tomorrow we may be able to find some clue that will tell which way the wind blows—it might be the print of a shoe in the earth or something like that. Lots of ways to pick up information, if only you keep your wits at work."

"Yes," returned Andy, "and if it's Frank Bird who's doing the thinking. But perhaps it would be silly in me sleeping out here tonight. I'd better be traipsing back to bed right now, because, you see, I'm only half dressed and it's chilly."

"Good. I'll see you to the house, because I've got to walk home, now that my wheel has gone up the flume," remarked Frank.

"What's the matter with you using mine?" demanded the other. "That plug you put in holds dandy, and there's nothing the matter with it right now. Same old place, under the side porch here. Guess the lamp is on the bum, but you hardly need that. If a cop holds you up, explain what happened."

"All right, I guess I might as well ride as walk. But I hope I get my wheel back. It's nearly new, you know, and cost a heap," Frank remarked, as he dove under the stoop, to presently appear dragging the other bicycle.

"Apply to Perc and Company for further information," called Andy, holding the door open a crack to shoot the words out and then closing it.

Frank, laughing at the obstinate ways of his chum, pushed the machine out to the road and was soon moving along. Evidently he lacked the same confidence in Andy's wheel that he felt in his own, for he made no attempt to speed as he went toward town and home.

Fortunately he met no policeman, who might ask impertinent questions as to just why he was riding after dark without a light. And reaching home he found his father sitting up in his office waiting to hear his report.

Dr. Bird was quite satisfied with what Frank had to say in regard to the condition of the sick girl. He knew that the boy was well up in medicine, even though he had never tried to push him in the least. Frank gave evidence of being what is known as a "natural born doctor," keenly alive to everything pertaining to surgery. More than once he had set broken limbs for dogs and cats and done it in a manner that aroused the warmest praise from his father, who, deep down in his heart, knew the boy had it in him to become a famous surgeon, if he kept along in this path when he came to take up his life pursuit.

Frank believed he ought to tell about the dastardly attempt to destroy the monoplane. And, of course, the good doctor, who always thought the best of people, was horrified to hear his story.

He shook his head sadly after Frank had finished.

"I don't know what people are coming to nowadays," he remarked. "No matter who did that mean act, it was wicked. Man or boy, he ought to be severely punished for it. The rights of property seems to be getting less respect every year. It puzzles me to lay the blame for this spirit at the right door. But things were not so in my young days, Frank. We live in fast times, my boy, fast times!"

Frank thought so himself, as he went off to his room. Imagine his father, some forty years ago, ever dreaming of building an air-ship and speeding through the upper currents, perhaps thousands of feet above the earth, at the rate of a mile a minute! And yet that was what he and Andy had been doing, thinking nothing of the feat, as they became accustomed to its performance.

Fast times, indeed!

Frank did not allow the startling incidents of the night to keep him awake. He knew just how to get a grip on himself and put all these things out of his mind, once his head touched the pillow.

Time enough in the morning to begin worrying about that lost wheel and trying to figure out who the firebug could have been.

At breakfast Frank had to go over the whole story again for the benefit of Janet, who had heard enough about it from the doctor before her brother came down to whet her appetite for more.

Frank could see that she shared the suspicions entertained by Andy. Janet knew Perc Carberry of old and despised him most heartily. At one time he had taken a great liking to Frank's pretty sister, but when she learned what his nature was Janet had cut him dead on the street. And from that day on she had believed Perc capable of almost anything.

"Even after you saved his life yesterday, too!" she exclaimed, indignantly.

"Hold on there, sis," cried Frank, laughing. "You're as bad as Andy, who is ready to condemn on general principles. We haven't got a scrap of evidence to prove Perc guilty. Just as like as not he would show an alibi if we accused him of it, and prove that he was at home all evening. So please don't mention his name to anybody or I may get in a scrape."

"But you're going to find out, aren't you!" demanded Janet.

"I surely hope to, and recover my poor bike in the bargain. Luckily I've got my name and address scratched on the underpart of the frame, if the finder only takes the trouble to look. And now I'm off downtown, to speak to Chief Waller about it."

Ten minutes later Frank dropped off in front of police headquarters. And no sooner had he alighted than the lad discovered that there was a buzz of excitement about the place, for several men were conferring and the chief himself seemed disturbed. He looked eagerly at Frank as the boy came forward and started to relate what had occurred on the preceding night out near the residence of Colonel Josiah Whympers.

Immediately the face of the chief began to light up and an eager glow shine in his eyes. It seemed as though what Frank was telling must have given him a connecting link that he had found himself badly in need of.

"Now we know where he went!" he exclaimed, calling to one of his men. "Go out to Colonel Josiah Whympers', Green, and see what traces you can get of him." Then once more turning to the astonished boy, he went on: "You see, we had a jail delivery here last night. A desperate scoundrel managed to slip away undetected and we only found it out this morning. And the man who got out was your old friend, Jules Garrone, the French aviator, who was caught by the help of the Bird boys and their bully little aeroplane! Get that, Frank?"

CHAPTER VII : ANDY RECEIVES A SHOCK
"Then it was Jules who set fire to our shed!" exclaimed the boy, astounded.

"None other, you may be sure," replied Chief Waller, nodding his head.

"And made off on my wheel?" continued Frank, beginning to grasp the truth.

"That's just what he did," went on the official. "Found he couldn't steal your aeroplane and was bound to lay his hands on something belonging to the Birds that would carry him out of danger. Glad you came, Frank. I'll just call up all the surrounding towns and ask if a bicyclist has been seen there. I hope you can describe the wheel so they might know it."

"Yes, I even know the number. Besides, I've got my address scratched on the under-part of the frame. But whatever do you suppose Jules wanted to set our hangar on fire for?" Frank asked.

"Huh!" replied the chief; "don't know, unless it was a spirit of revenge. Some of these French rascals have the same nature as the Corsican or the Sicilian and hug the idea of revenge to their hearts."

"Revenge!" Frank cried. "But when did we ever injure them? Oh, yes, I forgot! We chased them off at the time they tried to steal our aeroplane, and they even neglected to take those two suit cases of jewelry with them, so the stolen property was recovered."

"Yes," the chief went on, "and that wasn't all, either. Remember that it was you Bird boys who discovered that they were hiding in the old shack deep in the forest. You saw them near there when you were sailing over that region in your airship and reported to me. And so we surrounded the cabin and nabbed our game. It may be they learned who gave them away, and Jules, on finding himself at large, made up his mind to get even before running off."

Turning to the phone on his desk the chief now started to call up several of the neighboring towns. Some were only six or eight miles away, while others might be double that and more.

Frank knew where the road ran that passed the Whympers place and when finally the police head got Shelby he pricked up his ears. Immediately he saw Chief Waller show signs of sudden interest. A smile crept over his face as though he were hearing news that pleased him. Then he engaged in a hurried conversation with the police official at the other end of the wire, after which he turned to Frank.

"I think I've located your wheel, Frank," he observed.

"Over at Shelby, you mean?" queried the other.

The chief nodded in the affirmative.

"Yes, over at Shelby," he said. "It seems that early this morning a wagon belonging to a countryman coming in to market was stopped by something lying on the road. Getting down, the farmer found that it was a man, badly injured, as if he had taken a header from a wheel. And, indeed, a bicycle was found close by, with some parts of it damaged, as if it had been run at full speed against a rock, sending the rider ten feet away, where he landed on his head and was knocked out."

"Was it my wheel?" asked Frank.

"He described it, for the farmer brought both man and wheel to police headquarters, and there can be no doubt but that it's yours. And the unfortunate rider answers to Jules. Now, I'm going to get an automobile at the garage and go over. If you want to go along I'd be glad to have you, Frank."

"I certainly would," replied the boy, quickly. "I hope the poor fellow didn't go so far as to break his neck. But let me go after a machine for you, chief. I've got an errand at the garage anyhow, as my dad wants a mechanic sent up to potter at his little runabout, out of commission as usual. He's ordered a better car, you know, and is only waiting for it to be delivered. Shall I go?"

"Yes. Tuttle will know which machine I generally use when on official business, for you see the town pays the bill. Be back as soon as you can, Frank."

"Yes, sir," replied the other, hastening away.

The mystery was now solved, and, after all, Perc had been proven innocent on this last count. Frank laughed to think how amazed Andy would likely be when he heard the news.

"I only hope he doesn't happen to run across Perc before I get a chance to open his eyes," he was saying to himself, as he headed for the nearby garage. "Because I really believe Andy is mad enough to challenge our old enemy and throw the accusation in his teeth. Then there would be a high old mix-up, with Perc in the right for once."

It did not take him long to deliver both messages. He saw a mechanic start off to tackle the disabled runabout for the doctor, so he could carry out his round of morning visits by ten o'clock. And then a chauffeur ran a car out of the garage into which he invited Frank to jump.

When they arrived at police headquarters the chief was awaiting them. Evidently he was not at all averse to this delightful spin across country on a fine July morning and with nothing to pay. Official business might sometimes prove worth cultivating.

Presently they were off. Frank, of course, knew every rod of the way. He had more than a few times made the trip over to Shelby on his wheel in company with Andy. And since they had taken to the air they had looked down upon that road for miles, as they whirled along hundreds of feet up, discovering features about the landscape that they had never dreamed of before they had this "bird's-eye view," as Andy delighted to call it, playing upon their own name.

In due time they reached Shelby and drew up in front of the building where the police held forth. The first one to meet their eyes as they entered was a familiar figure seated in a chair and attended by a doctor and a couple of officers.

"It's Jules, sure enough!" said Frank, as, despite the many bandages about the head of the man, he recognized the dapper little French aviator with whom he had had more or less trouble in the past.

And Jules grinned as he saw them. His spirit was not crushed, even though it began to look as though he might be the football of fate.

"It ees ze fortunes of war, messiers," he said, wincing at the pain speech caused him. "And after all, it was ze machine of ze young inventor zat downed me. I am von lucky man not to haf been five thousand feet up in ze air when it occur. Had eet been ze monoplane zat kicked me, pouf! poor Jules he would haf been as flat as ze pancake. As eet is, after I haf serve my time I am yet alive."

Frank found his bicycle badly damaged. In fact, the front wheel was smashed beyond recovery, for it had been driven against some stone at a tremendous pace. Strange to say, the lamp had gone through it all without any apparent damage.

"A few dollars will fix it up, all right," he said, cheerfully. "And I guess I ought to be thankful ever to see it again."

So he placed the wheel in the back of the big touring car. The doctor announced that Jules might be moved without danger if they were careful, and this Chief Waller promised he would be.

"You're giving us a heap of bother, Jules," he said, after the captured rascal had been safety stowed away in the tonneau of the car, with the chief beside him and Frank mounting to the front with the chauffeur. "But this winds you up. I understand your trial comes off tomorrow and you'll soon be snug in the pen."

"Zat was ze knowledge zat urge me to break out," remarked the prisoner, blandly.

"Well," remarked the other, with a tightening of his lips, "we'll make sure you don't get another opportunity, that's all."

Frank watched as they drew near the place of Colonel Josiah. He anticipated that the prisoner would be eager to look across the field to where the shed stood. Nor was Frank surprised to hear him give a low cry.

"Eet is wonderful, ze luck zey haf!" Jules remarked, as he discovered that the hangar had not burned to the ground as he expected, and after that he relapsed into gloomy silence.

Frank had caught sight of Andy passing along the street ahead and entering the Bloomsbury postoffice. So as soon as he could get his broken wheel into the bicycle store, where he left orders for its being fixed at once, he hurried off, in hopes of intercepting his cousin and breaking the great news.

He was just in time to see Andy coming out of the building and staring hard at something he held in his hand. Frank could see that it was a letter and he also noticed that his chum was unusually pale.

"Now I wonder what he's got?" asked Frank, talking to himself, as many boys often do at times. "Looks like a letter, too. Once in a while the colonel asks him to go down when the mail comes in and see if there is an important one for him, which he can't wait for the carrier to bring out. And Andy has got one this time, sure."

A moment later and he came upon Andy, who at sight of his chum showed signs of relief.

"I'm awful glad you came along, Frank," he said, seizing the other by the sleeve; "I was at your house and they told me you had gone downtown somewhere. Then, as the mail was in, I remembered Colonel Josiah was expecting one of his letters from London, and so I dropped over. But there was nothing for him. Mr. Guthrie handed me out this and said he guessed it was for me. Oh, look where it is from, Frank! Do you think—can it be possible that it means some news, after all this time, from my father?"

Frank saw it was rather a bulky letter and that the postmark showed a station in South America. Remembering all that had passed between them in connection with this country he understood the cause of Andy's great emotion.

"I was almost afraid to open it, Frank," said the other, brokenly.

"Well, do it now," remarked Frank, and Andy tore the end off hurriedly.

He appeared to read hungrily for a minute, and then gave a cry of amazement.

"Oh!" he said, taking in a big breath, "how strange! how wonderful!"

CHAPTER VIII : THE MESSAGE
Frank Bird could restrain his curiosity no longer.

"What is it, Andy?" he asked, as he laid an affectionate arm across the shoulders of his cousin.

The other turned his eyes upon Frank, and there was something in their depths that stirred the other tremendously.

"Is it about your father, Andy?" he demanded, eagerness plainly showing in his whole manner; for he understood what a hold the subject had on his chum.

Andy nodded, and as soon as he could command his quivering voice, said:

"Yes, nothing more than a letter from the grave, I fear! See, Frank, written in his own dear hand. Oh! to think of it, that at least three months ago he was alive, even though a prisoner, the sport of fate."

"A prisoner!" echoed Frank, astonished. "Whatever can you mean? Did he fall into the hands of some of those strange Indians we have been reading about, who have their homes around the headwaters of the Orinoco River in Venezuela?"

This time Andy shook his head in the negative.

"It is stranger than that—almost beyond belief!" he replied. "My poor father has for months been imprisoned in a great valley, surrounded by impassable cliffs. Don't you remember something of the sort occurred in one of Captain Mayne Reid's books, where the young plant hunters found themselves prisoners in that way? But here, Frank, look for yourself."

"Where does the letter come from, in the beginning?" asked the other, quietly, wishing to advance by slow degrees, so that he could understand everything.

"A town in Columbia, called Barranquila," replied Andy, readily enough. "I'm not sure, but I think it lies at the mouth of the big Magdalena River, and is upon the coast. You know I've just devoured the map of that region for months, and every name is familiar to me."

"Besides this queer communication, which you say is from your father," Frank went on, "there seems to be another letter?"

"That is from Señor José Almirez. Read it, Frank, and you will begin to understand."

The letter was in a crabbed hand, apparently unused to writing in English, though grammatically correct. And this was what Frank saw:

"To Señor Andrew Bird:

"I received the enclosed from a correspondent and customer, one Carlos Mendoza, located in the vicinity of Manangue, a town about one hundred and fifty miles up-river.

"He is a grower of cocoa in the rich valley. I do not enclose his letter, because it is written in Spanish. But it simply says that he found the written communication close to his plantation house one morning in April of this year. At first he could not understand how it came there. Then, upon having the writing translated, he noticed that the missive was attached to what seemed to be a little parachute, or balloon, made up of a fragment of silk belonging to a balloon. Knowing that I had spent several years in Washington, in the service of my country, he finally concluded to send the same to me. I have the honor to transmit it to the address given in the communication.

"With respect, and expressing a willingness to help you all I may, Señor Andrew Bird, believe me to be most sincerely yours,

"José Costilena Almirez."

Frank read this amazing communication, and then turned to stare at his cousin.

"No, don't stop yet!" exclaimed the trembling Andy. "Read the other, the missive that Carlos Mendoza picked up on his cocoa plantation, in the valley of the Magdalena River."

And so Frank again turned his attention to the enclosure that had been sent on by the friendly merchant of Columbia.

It seemed to be a sheet of thin but pliable bark from a tree, and in some respects reminded Frank of birch bark, which he had often used in lieu of paper, when in the woods. The juice of some berry had afforded ink; and doubtless the college professor had easily made a pen from a bird's quill. And this was what Frank read, a small portion of the communication being missing, as though it had received rough usage somewhere, en route:

"Whoever finds this, I pray that it be forwarded to Andrew Bird, in the town of Bloomsbury, State of New York, U. S. A. In my balloon I was carried away by a sudden storm while crossing the Isthmus of Panama. As near as I can calculate I was swept some three hundred miles, more or less, in a south-easterly direction, much of the time above the clouds. Then something happened, and I felt myself falling. Giving myself up for lost, I awoke from a swoon to find myself in the branches of a tree, with the wreck of the balloon near me. A merciful Providence has saved my life, but I fear only to prolong my agony of soul. For months now I have been a prisoner in a remarkable valley, a sink-pit, enclosed by inaccessible cliffs. Many times have I struggled to climb to their top, but only to meet defeat.

"All this time I have sustained life by means of fruits that grow in abundance in this tropical valley. In the hope that I may manage to communicate my horrible condition to the outside world I have made scores of small parachutes, and when the breeze at the top of the cliffs appeared favorable, send them up by means of hot air, each carrying a message to my son. God in His infinite wisdom only knows if one of these will ever reach him. I shall continue to have hope, and sustain life as long as my mind remains—

"Professor Philip B——"

When he had finished this astonishing document Frank turned to his chum.

"Oh! what a remarkable thing! I never heard its equal in all my life. To think that your father has been alive all these months, though a prisoner in that cliff-bordered valley! But Andy, don't you see that now nothing is going to keep us from going down there, and finding him? Here is the clue you wanted, only instead of discovering his sad fate you are going to rescue him, and bring him home again!"

They reached out and gripped hands. There was something in that act to stamp the more than brotherly feeling existing between them.

"Do you think we could do it, Frank?" exclaimed Andy, more than ever willing that his clear-eyed chum should take the lead in this most eventful moment of his whole young life.

"Sure I do," answered the comforter, readily. "Didn't we conquer one battery of cliffs that were said to be insurmountable, when we sailed in our dandy little monoplane up to the crown of Old Thunder Top, and snatched that silver cup for a prize? Make up your mind, my boy, that that was just meant to get us in practice for better things. The time's come for us to show what we're made of. And instead of a silver cup, the prize this time will be—"

"My father's life!" murmured Andy, tears in his eyes, as he again squeezed that faithful hand which held his so firmly.

"That's right," Frank continued. "We can go straight to this fine Spanish gentleman, Señor Almirez, and get all the points he knows. From there we'll get up-river to this valley town and visit Carlos Mendozo on his cocoa plantation. Depend on it he'll be able to set us on the track, somehow or other."

"Oh! it seems like a strange dream," said Andy, as he raised the piece of bark to his young lips, and passionately kissed it, regardless of the fact that some one passing the post office might notice him.

"Well, you want to wake up right away then," remarked Frank, smiling, "because we've just got to get a hustle on us, if we're going to start on this wonderful trip. Here's where our aeroplane is going to help us out. Just imagine how we can pass over regions where it would be next to impossible for us to navigate on foot—mountainous country, tropical valleys where wild beasts roam and poisonous snakes abound; and jungles where the natives have to cut a passage foot by foot, I understand, with their machetes. And to think that we can sail freely over it all, looking for that spot where that bark letter came from."

"Come, let's go home!" exclaimed Andy. "I'm sure Colonel Josiah will be tremendously interested in what we've learned. He'll be the most disappointed man in the whole U.S. just because he's so crippled that he can't go along. For many years he's traveled in every country under the sun. Perhaps he might tell us more about the interior of Colombia than we know right now."

Accordingly they hurried away. Frank came near forgetting the news he had been bearing at the time he met his cousin. But then, that was hardly to be wondered at. The capture of the escaped robber was of minor importance when compared with this wonderful business connected with Professor Bird.

And just as Andy had said, Colonel Josiah was tremendously interested when he heard about it, and with his own eyes looked upon the letter that had come from a living tomb.

"Somebody pinch me," he said, looking at the boys almost helplessly. "I surely must be asleep, and dreaming this. It seems too strange to be true. Philip alive all these months, and in that terrible situation, while we were enjoying the good things of the world up here. It is monstrous! You must go down there with as little delay as possible, Andrew. Who knows but what it may be your blessed good fortune to rescue your dear father, and bring him back with you. Money—all you need; and the prayers of an old man go with you."

"But think," said Andy, uneasily, "this was written three months ago. What may not have happened in all that time? There must be beasts in that sunken valley, and doubtless many poisonous reptiles. Perhaps—"

"Hold on!" cried Frank, interrupting him, "don't you go to imagining all sorts of terrible things. He had been there at least nine months already. Nothing had happened to injure him. He does not even hint at such a thing; but says he means to sustain his life as long as he retains his proper mind. Your father was not in the least like you, Andy. He possessed a wonderfully well-poised mind, and laid out his plans with deliberation. Believe me, the chances are ten to one he is still there, and waiting. We are going to find him. Don't allow any other idea to take possession of your head. Find him, do you hear?"

Of course that sort of talk had its effect on Andy, and he braced up. They began to make preparations and plans without delay. The monoplane was taken apart, and carefully crated. Then Frank ran down to the city and returned with several duplicate parts, secured at an aeroplane agency he knew of, and which would come in handy in case of an accident in that strange country, where they must depend entirely on themselves.

For two days there was a tremendous lot of bustle around both homes. Dr. Bird had no longer any valid excuse for refusing Frank permission to go, since it was a mission of mercy that beckoned the boys on to that South American mountainous region. Besides, he had always been very fond of his elder brother, who had done so much to make the name of Bird famous, in college and out; even though the professor had thought best to make his old friend, Colonel Josiah, his boy's guardian instead of the physician.

The aeroplane had been shipped to New York, to be put upon a steamer sailing for Maracaibo, in Venezuela, and which they expected to take also. From this port they would have to make their way to the mouth of the Magdalena River by means of some smaller craft. But with virtually unlimited means to back them, the boys did not fear but that they could overcome any difficulties that might arise in their path. Indeed, Frank had a disposition that would never allow anything to balk his plans, if it were at all within the power of human nature to accomplish results.

The last thing they heard, just before leaving Bloomsbury, was that Perc Carberry and his crony, Sandy Hollingshead, had gone away, taking their biplane along; and it was said that they expected to do wonderful stunts with their airship somewhere in the South. But our two boys were too deeply interested in their own fortunes to give more than a passing thought to the flitting of their rivals. Besides, it would not seem that there could be one chance in a thousand that they would ever run across Perc and Sandy in all that great country, lying south of the Caribbean Sea, and north of the mighty Amazon.

And one morning Frank and Andy said goodbye to those whose best wishes were wafted after them, taking train to New York City, so as to go aboard the steamer, that was scheduled to sail that P.M.

CHAPTER IX : UNDER TROUBLED SKIES
"Oh! how glad I am to think we've arrived at last!"

Andy uttered these words as he stood at the rail of a small but staunch steam yacht, of rather ancient vintage, that he and Frank had leased when arriving at Maracaibo, the city on the bay of the same name, from whence so much of Venezuela's coffee is shipped to the States.

It had belonged to some Englishman who, becoming stranded at this South American port while on a globe circling trip, was forced to let it go; and the agents gladly secured a crew for the adventurous young Americans, who were bound up the Magdalena River for some unknown purpose.

"Yes," observed Frank, who leaned on the same rail close beside him, "there's the town of Barranquila, all right. We've navigated the five hundred miles in this little steam craft" with only a few break-downs of the machinery, and just two days' delay. And the second step on our journey comes to a close."

"The third ought to take us to that valley town up the river; ain't I right?" asked the anxious Andy.

"Sure. As near as I can make it, Magangue must be not over two hundred miles upstream. With good luck we can cover that in a couple of days," returned Frank.

"But why do you say good luck?" demanded his cousin, suspiciously.

"Oh! well, we are now in the land of tomorrow, you remember," laughed Frank.

"You mean where they put off everything they can, saying 'no hurry; plenty of time, señors all; the world was not made in a day'? Is that it?" Andy went on.

"Partly. I was also thinking of another thing," admitted Frank.

"Yes, and I bet I can give a mighty good guess what it is, old fellow."

"Perhaps you can," Frank said, a little gravely. "Suppose you spout it out."

"You've been pondering on what old Quito was telling us, in his broken English, about this little revolution that has been slumbering around the region of the Magdalena River of late. You have a hunch that we may just be unlucky enough to run across some of those ragged chaps, who want to upset the present government of Colombia, and seat some old ex-president fossil in the chair again."

"Anyhow, you're a fine guesser, Andy," admitted Frank.

"Then that's what was on your mind?" asked the other. "I've noticed you frown a whole lot lately, which is unusual for my cheery pard, Frank."

"Oh! well," observed Frank, calmly, "I acknowledge the corn. I was wondering whether we might be troubled by any of those fellows while we were navigating this river. I hope they'll just let us severely alone. But you know, Andy, just as Colonel Josiah warned us, these Colombians don't have any too much love for Yankees, ever since that Panama rebellion, when, as they believe, our government openly assisted the people of the Isthmus throw off the Colombian yoke, because we just had to control that strip of territory for the canal."

"But why should the revolutionists want to stop us?" insisted his cousin. "We are here only on a private quest. We seek no gold mines or cocoa plantations. Our only object is a mission of mercy. And besides, if these men are in open rebellion, they ought to be glad to see anybody that their government detests, Yankees or not."

"Well," pursued Frank, with a cautious glance around, "I was thinking that some of the people in Maracaibo took altogether too much interest in our little monoplane. A lot of dark-faced men hovered around, and asked many questions. They have heard and read much about the wonderful things being done today in aeronautics, but have seen little or nothing."

"Frank, that's so!" exclaimed Andy, quickly. "Please go on. You are gripping my attention a heap, I admit. Tell me, do you suspect that some of those same chaps may have been Colombians?"

"I'm dead sure of it, and more than that, old Quito gave me to understand he believed they were connected with the junta that was pushing this new revolution in Colombia."

"Yes?" Andy said, in a way that plainly invited further explanation.

"Stop and think," Frank continued. "Suppose now, they conceived the idea that it would further their forlorn cause a heap if they only had such an airship, and could threaten to drop all sorts of bombs into the camps of the government troops!"

"Good gracious! I suppose that is so. I never thought of that, Frank!"

"You know how nervous and excitable these people are? Don't you think they'd give the government the worst scare it ever had? And couldn't they make almost any sort of terms of settlement?" Frank demanded.

"Yes, that's true. Then you imagine those fellows may have planned to somehow steal our aeroplane, and that they've sent word ahead to their friends along the Magdalena to look out for us?" was Andy's startling question.

"Partly that. But don't you see, Andy, the little monoplane would be utterly useless to them unless they had some one who knew how to run it?"

The other gave utterance to a low whistle, just to indicate how his feelings had been stirred.

"You mean they might try to capture us in the bargain, and force us to operate the aeroplane? But suppose we did, what would hinder our just sailing away, once we got up in the clouds? Tell me that, Frank?"

"Oh! well, I'm not looking that far ahead," smiled the other. "Possibly they might only let one of us go up, keeping the other as a hostage. Or perhaps, there might be a fearless revolutionist officer aboard with that one, sworn to shoot at the first sign of treachery. But don't let us cross a bridge until we come to it."

"That's right. We don't want to fall into the hands of any ragtag revolutionists, and we won't! We've got our work laid out for us, and nothing must stop us. All the same I'm going to keep an eye on that precious case in which our aeroplane is boxed, as well as the engine. And Frank, I'm carrying the little shooting-iron Colonel Josiah gave me as a parting present."

"Ditto myself," replied the other, in a low tone, as one of the crew happened to draw near, while getting ready to make a landing at the wharf. "He told us that down in this country it paid to be ready for trouble; though I keep hoping we're not going to have anything of the sort."

It was toward noon when they steamed up to the town that nestled near the mouth of the great Magdalena River. Of course it was hot, for the season of the year made that a foregone conclusion; but both boys were dressed in suitable attire, and also wore pith helmets calculated to allow a current of air fan the head.

Andy was shivering in a mixture between hope and fear. In this city they would meet the writer of that pleasant letter, Señor José Almirez. What if he had received further intelligence from the correspondent up-river since the time he had mailed that letter? What if some terrible news awaited the coming of the daring young Yankees, who had ventured to this faraway country, bent on solving the mystery connected with the long absence of Professor Bird?

But, as usual, it was Frank who buoyed his spirit up. There never was a chum more devoted to the interests of his friend. Andy would long since have succumbed to his fears but for the cheery words of the other.

It was said to be the rainy season in this country that lay in the tropics. Up on the high mountain peaks lay snow the year around; but in the low lands, and along the valleys and sides of the uplifts, they could grow coffee, cocoa, bananas pineapples, oranges and all manner of similar products.

A small crowd gathered at the wharf to see the little steam yacht come in. Perhaps the former English wandering owner had been here before, and some of them even recognized the vessel.

Scowls greeted her passengers when it was discovered that they were not English but Americans. Frank and Andy paid little heed to these frowns. They did not mean to leave the boat, if so be it were possible to have Señor Almirez come aboard. And for that purpose they had written to him ahead of time, telling him how they expected to reach Barranquila about a certain date.

Several breakdowns of the engine had delayed them, so that they were even now two days behind time. On this account, as well as through prudence, they meant to stop here as briefly as possible.

Immediately their purser went ashore to make inquiries, and purchase a lot of fruits that could be taken on the river voyage; though for that matter they might expect to get anything they wanted at various villages along the route.

Frank was looking the crowd over closely.

"I think I see him, Andy," he remarked, presently.

"You mean Señor José?" asked his cousin, eagerly. "I've been watching that middle-aged gentleman who seems to be pressing close in on the flank of the crowd. There, see, he is speaking to Manuel, our purser, now, asking him some question. He looks up here at us; yes, and waves his hand, with a smile! That must be Señor José, all right, Frank."

"I'm going down to meet him, to fetch him aboard," declared Frank, after both boys had answered the signals of the dark-faced gentleman in the white linen suit, and who was also wearing a Panama straw hat.

Three minutes later and Frank reappeared, having the other in tow.

Just as both of them had suspected it was Señor José. Receiving their communication from Maracaibo, he had been on the watch.

"And he tells me, Andy, that there has been no new development since he wrote. So that fear of yours must be set at rest. Just depend on it, we're in this game to win out, and your dear father is going to be found," Frank went on.

Presently they were deep in conversation. The boys found Señor José a very intelligent gentleman indeed. He had spent some years in Washington in connection with the embassy of his government, so that he not only spoke and wrote English well, but had a high opinion of Americans; something that the vast majority of his fellow-countrymen failed to acquire, being possibly fed on stories that may have had their inception in German or English trade sources.

From him Frank extracted all the information he could concerning the wonderful country lying between Magangue and the Isthmus of Panama, covering possibly some three hundred miles. It was little enough. Most of it, he declared was a terra incognita, being utterly unknown land.

"But," continued the obliging señor, "you will certainly be able to learn more concerning this when you see my fellow-countryman, Señor Mendoza; for all his life has he lived there at Magangue, and surely he must know something of that country to the south."

"We shall leave here with as little delay as possible," observed Frank. "I have sent our purser, Manuel, to comply with the custom duties, and secure us a few supplies. When he comes aboard again we expect to start."

"It is just as well," remarked the other, significantly, and seeming to be relieved. "Because, there is an uneasy feeling in Barranquila just at present. Agents of the revolutionary junta have been here. They are very active. And from secret sources I happen to know that they are aware of the strange cargo you are bringing with you."

"You must mean our aeroplane, Señor?" remarked Frank, quickly.

"Si, Señor Bird," the other continued, nodding his head. "It has become known that the two young Americanos are of the new and wonderful aeronauts, with whom nothing is impossible. And if you remained here any length of time I fear lest even my government might seek to find some excuse for appropriating your little airship. The talk is all in that direction now. Colombia is ripe to take a forward step, and have an aviation corps."

"Well," said Frank, "under the circumstances we would seriously object to having our monoplane confiscated now, because upon it we depend wholly in our search. But I thought you were perhaps about to warn us to look out for these revolutionists while passing up the river."

"It would be wise, Señor," observed the amiable Colombian ex-diplomat. "They have agents here; and I happen to know that one is even now on the wharf, observing. Possibly he seeks to communicate with some spy who chances to be a member of your crew. So you see, it must pay you to be always on your guard, and prepared!"

CHAPTER X : NIPPED IN THE BUD
"There comes Manuel!" remarked Andy, after they had been nearly an hour talking on the deck of the little power boat.

"Yes," remarked his cousin, who was also on the watch, "and trailing behind him I can see several native carts containing fruits and new supplies. Manuel surely means that we shall not go hungry while on the river."

"Then I shall be going, my friends," said Señor José. "I have told you all I know. I have warned you to beware of the revolutionists along the river bank. I have even given you a hint that to delay longer in Barranquila might endanger your enterprise; since the government is just now very anxious to acquire such wonderful modern agents of warfare, as your aeroplane. It only remains to shake your hands, both, amigos, and wish you every good fortune your valor deserves."

They squeezed the hand of the fine old Colombian gentleman with vigor. Never would Andy forget how he had spoken concerning his interest in the sacred duty that had brought the son of the missing aeronaut to his country.

Frank had given strict orders that none of the crew should go ashore, and also that no strangers be permitted to board the craft while they lay there at the old wooden wharf.

"But," said Andy, when they were speaking about this matter, as preparations began to leave the port, "that hasn't prevented the crew from holding an animated confab with those ashore. There has been a constant jabbering and laughing between our fellows and those others."

"Yes," admitted Frank, "and I've seen several of the crew talking mysteriously with some of those chaps. I wish now the señor had thought to indicate which was the secret agent of the revolutionists he saw on the dock. But all the same I've marked the two fellows I suspect, and I'm going to keep a close eye on Enrique, and the little fellow with the quick motions we call 'Cospita,' because he's forever ejaculating like that."

"And if you find out that they're meddling with the boxes?" asked Andy.

"H'm! I guess it'll be a bad day for Enrique and the jumping-jack, that's all," laughed his cousin. "But there goes the cable, and it looks like we might be off at last."

"I'm not sorry, for many things!" declared Andy, with a sigh of positive relief. "The good señor got me scared by what he said about his government wanting just such things as our little 'Bug'; and that the officials might have orders to find some sort of ridiculous excuse for grabbing it."

"Same here," admitted Frank. "In fact, that bothered me a whole lot more than the chances of trouble along the river from the boys who want to get their man seated in the president's chair, where he could hand out the loaves and the fishes. We can resist them, and be backed by authority; but if the government officers once took us in we'd have to give up our job. And that would break your heart, Andy."

"Yes," said the other, drawing a long breath, "I'm afraid it would. Listen! There goes the whistle. I told the pilot not to make more fuss than he could help when we drew out."

"Which was quite right. I'm watching that little chap, Cospita. See him wave his hand to some one ashore? Yes, and that surely looked like a signal the fellow returned. We are going to have trouble with that boy yet, Andy."

"Well, that will be bad for Cospita," was all the other remarked; for he was eagerly watching the growing space between the boat and the shore.

"Look, Frank," he remarked, after a little time had elapsed, "as sure as you live, there is an officer in uniform just arrived on the dock, and backed by a squad of soldiers! He seems to be surprised at discovering that we have gone! Now he beckons, and waves his hat! Listen to him shouting something in Spanish through his hands. I guess we didn't get away from Barranquila five minutes too soon!"

"It looks like it," said Frank, grimly. "But we've complied with the law of the land, and nothing short of a cannon could make us turn back now. All the same, I'm going to the pilot house, and keep an eye on Felipe. I think he's trustworthy; but an ounce of prevention is better than a pound of cure always."

"Good for you!" Andy shot after his departing chum; though he himself remained there by the rail, watching what took place ashore.

Frank quickly entered the pilot house. Here a dark-faced, middle-aged man handled the wheel. Frank immediately noticed that he was listening to what the gold braided officer ashore was shouting angrily. He also looked a bit troubled.

"What does he say, Felipe?" demanded the young aviator.

"He commands us to return, señor," replied the other.

"Well, pay no attention to him, Felipe. We have complied with all the regulations and red tape necessary. The American consul will back us up. It is your business to simply steer this boat up the river until we arrive at Magangue."

"Si, señor. But when I return they will surely make the trouble for me," replied the pilot, shrugging his narrow shoulders.

"Not at all, Felipe," declared Frank. "You can swear that we made you do as we wished; that you dared not turn back, since your life was in danger. We stand ready to shoulder all the blame there is."

The dusky face of the old river pilot, whom they had fortunately run across in Maracaibo, became wreathed in a smile.

"Perhaps the young señor would not mind showing the Capitan?" he suggested.

Frank grasped his meaning; and pretending to scowl darkly, he drew out the revolver which Colonel Josiah had made him promise to carry while down in this explosive country.

"Now, Felipe," he said, as he clapped the weapon deliberately against the head of the pilot, "your gay Capitan can easily see what I am doing, and will understand what it means. You keep right on up-river; and if you dare disobey it will be bad for you, Felipe!"

The shrewd old pilot tried to smother an expansive grin as he replied:

"Si, señor, I am in your hands; do with me what you will. I dare not refuse longer. See, I have made one effort to turn about; but you threaten, and I give it up. He no longer calls. He knows old Felipe is powerless. It is well!"

Frank stood by him until the wharf was dimmed by distance. Then he hastened to rejoin his cousin and chum, who was mightily pleased to hear all about it.

"Do you think they will chase after us?" queried Andy, still worried.

"Oh! I guess not. It isn't so serious as all that. They know they can get us when we come down the river, no doubt," replied Frank, carelessly.

"Then I'll care precious little what becomes of the Bug," observed Andy, with a sigh of relief.

"I suppose you mean that by that time you'll either have found your father; or else given up the search as hopeless. Is that it, old fellow?" Frank asked.

"Yes, one or the other. And now, we've got time to remember the other warning good old Señor José gave us."

"About the revolutionists trying to stop us on the way and get our cargo? Yes," Frank went on, "that must be on our minds constantly. I'm going to talk with old Felipe about it soon. I have a hunch that he can be depended on to back us up, for he's got a grudge against the man these fellows want to send back into the presidential chair. Señor José told me Felipe lost all his family through the persecution of that man and his party."

"A bully good thing to know," assented Andy. "For we can be dead sure of Felipe all the time; and through him get pointers about the rest of the crew. There are a few goats among the sheep, and when we make sure of it, I'm just going to pay them off, and chuck them ashore in any old place."

"Now that's what I call a clever scheme," Frank declared. "They would have no kick coming, because, you see, no Spanish American could ever complain of getting his wages without having to do any work!"

"I guess not," Andy remarked, grinning assent.

Upon further conference it was decided to divide the day and night into watches, so that one of them could be on deck and alert all of the time, while the other secured some sleep.

Treachery, they knew, would be likely to crop out during the night time. Those on board may have found some means of telling their confederates ashore about what time the boat would reach a given point. And by means of some native method of telegraphing, such as by means of wigwag flags, or "smokes," the news could be hurried up the river much in advance of the vessel that was butting against the strong current of the swollen Magdalena.

Then Frank went forward to have a long talk with the trusty pilot. He took Felipe into his confidence, telling him for the first time all about their sacred mission to this region of Colombia. And in this way, as well as by promising to double his regular wages, Frank quite won the old fellow's heart.

In return Felipe was able to give his employer considerable valuable information connected with the crew. Frank mentioned no names, and hence he was satisfied that he had made no mistake in his calculations, when among the list of "suspects" given by the pilot, both Enrique and little "Cospita" were included.

"We must get rid of them both as soon as possible," he announced. "So just before night sets in, draw the boat to shore near some village or town. Then I shall pay both men off, get their signatures to the fact, and insist on their going ashore. Meanwhile, as you find opportunity, post a few of the faithful ones to the fact that we suspect them of being insurrectoes."

Felipe declared that the idea was superb. He was growing more and more fond of these venturesome young Americanos, who were so generous, so brave, and who had come all this great distance, actuated by such a noble purpose. So many a man may easily feel when his salary has been unexpectedly doubled.

During the balance of that afternoon the two young aviators continued to alternately sit upon the deck, and wander about the boat, watching things. Frank had the precious aeroplane locked up in the spacious lazerette, which being also used as a storeroom for extra supplies, that the circumstance need not be looked upon as singular.

"I'm determined that no ill may happen to that machine, if I can help it," he said to his chum, when speaking of what he had had done.

And Andy, of course, fully endorsed his course.

So the sun began to draw closer to the western horizon, represented by the distant mountains where the chief inland town of the province, Sabanalarga, lay.

Felipe had spoken of a place on the eastern bank of the river, where they could draw in, and put the two suspects ashore. And Frank told Andy to back him up in what he was about to do.

"There's the town ahead, only a little place, but it answers our purpose, for they can never say we deserted them in the howling wilderness," and Frank, who had been counting out some money, started to make his way down to the waist of the vessel, where most of the crew had gathered, wondering what the object of the landing might be.

Enrique and "Cospita" were surely very much astonished and alarmed when told that their services were needed no longer—that it was ascertained they were carrying too many men; and also that they were to receive full pay for the time they had engaged.

Of course they started to make objections, and the air was filled with various excited exclamations; but Frank proved as firm as adamant, and showed the automatic revolver sticking from his pocket all the while, a fact that kept the two men from venturing to do more than shout.

Clutching their money they were pushed ashore by members of the crew, who doubtless could give a pretty good guess as to what the whole thing meant, since they had talked with Felipe.

"A good riddance of bad rubbish!" declared Andy, as the boat again started up the river, leaving a pair of yelling natives behind, making all sorts of furious gestures with both arms.

"Yes," pursued Frank, reflectively, "and if we wanted any more evidence that we nipped a conspiracy to seize the vessel in the bud, there it is in their anger at being paid for not working. Nothing like that was ever known before down in this country, as Felipe says. And now, Andy, I feel that we're another step nearer the carrying out of your great task."

"Oh! I hope so," said the other, his face marked by an eagerness that told of the one sole wish of his youthful heart.

CHAPTER XI : OUT OF THE FRYING PAN INTO THE FIRE
Frank took the first watch.

It was to begin about ten o'clock that night; for both of them had remained on deck, talking, up to that hour. The night was so comfortable after the hot day that they disliked going into the sleeping quarters. These happened to face the deck, however, so that the vessel was admirably suited to cruising in tropical regions.

"Every thing seems to be going on decently right now," remarked Andy, yawning, as he prepared to have a few hours' sleep.

"That's so," returned his chum. "But while we've got some of the faithful ones on duty, we mustn't forget that there may be other snakes aboard. Enrique and the little shouter may not have been all the sympathizers with the revolutionists. And not for a minute will we relax our vigilance."

That was Frank's way; and just now Andy fully approved of it. His heart was so set upon having a chance to use the monoplane in the endeavor to discover that strange cliff-enclosed valley, where his father was imprisoned, that he did not mean to take any chances of losing out through over confidence.

So he packed off to his berth, while Frank prepared for three hours of lonely vigil. He expected to make the rounds just about once in so often, and have a few words with the man at the wheel. Felipe had declared that it was his intention to keep busy himself through the night, since he dared not trust the wheel in the hands of an inexperienced pilot while darkness lasted.

In the morning he could give directions, and allow an assistant to do the work, while he secured some rest.

There was no moon after early in the evening, when the young queen of the night disappeared in the west, leaving the bright stars to control the skies.

The boat continued to make good headway against the current, though at this season of the year the Magdalena is bank full with the summer rains, which fall almost every afternoon in a deluge.

A searchlight sent a dazzling shaft of light far ahead on the troubled surface of the booming flood. This was an absolute necessity, for otherwise it would have been too dangerous bucking against that tide; laden as the river was with floating tree trunks of gigantic size, that had been swept from their resting-places in the lowlands above.

Once Frank had seen a wild animal crouched on one of these great logs. The boat passed so very close to the floating refuge of the beast that ere darkness claimed the strange craft with its stranger cargo, Frank had been able to see the tawny hide of the crouching beast, and note the quick, jerky motion of its long tail.

Upon hurrying to the pilot house and making inquiries of Felipe he learned that, just as he suspected, the animal was a jaguar, the most feared inhabitant of the tropical forests away off at the headwaters of the Magdalena and Orinoco rivers.

There was a spice of peril hovering over the progress of the little boat during every hour of that night. It might come in the sudden leap of a wild animal, that judged any port would be better than a floating log. Then there was a chance of their running afoul of a monster derelict, in the shape of a drifting snag, that might punch a hole in their bow, and bring about trouble.

On top of all was this unseen peril from the revolutionists, who were making the Magdalena country the center of their renewed activity, for some reason or other, and had their minds set on securing the first aeroplane ever known to be in Colombia.

The time passed away. When three hours had really gone, and all seemed well, Frank awoke his chum. Generous to a fault, he might have held out much longer, for he did not feel exhausted; but Andy, who knew him like a book, had made him promise faithfully, on his word of honor, that he would arouse him at exactly the time agreed upon.

"Everything lovely, and the goose hangs high!" Frank said, as the other joined him presently on deck.

"That's good," replied Andy. "And as it is now one o'clock, with no trouble doing, looks good to me that we'll pull through the night without a mess."

"You never can tell," observed the careful Frank. "And the only way to do is to act just as if you felt positive something was bound to crop up."

"I know it," came the reply, as Andy started to walk up and down a bit, so as to get the last remnant of drowsiness out of his system.

For an hour he found little trouble in keeping awake. He made frequent trips to where Felipe stood at his wheel, his keen eyes keeping constant vigil ahead, in order that he might steer clear of such snags as threatened to stove a hole in the hull of the steam yacht.

Now and then Andy could see one of the crew moving about; but as some of them must have duties to perform, even in the night, he did not look upon this as a suspicious circumstance. Only, he made sure that no one wandered in the near vicinity of the locked lazerette, where the precious monoplane lay, securely crated.

In some places the river proved much narrower than in others. And, of course, it was here they had their greatest trouble. The current was increased, for one thing. Then the floating objects swept forward with more speed, so that it required additional dexterity in order to avoid them.

But old Felipe knew his business well. Andy believed they had made no mistake in leaving matters fully in his hands.

It was about the end of his second hour that the pilot volunteered some information that gave Andy more or less uneasiness.

"Just ahead, young señor," he said, when for the fifth time the boy entered his deck pilot house, "we come to the narrowest place in the whole river at this section. And there, if anywhere, I expect that they will be waiting for us."

"Do you mean the revolutionists?" exclaimed Andy, interested instantly.

"No other, señor. If we manage to get past there, all will be well. But they may be encamped on both shores, and demand that we draw in under penalty of being fired on," Felipe went on, without removing his snapping black eyes for even a single second from the ever-moving panorama of shifting water and floating debris, that the searchlight disclosed ahead of the laboring boat.

"But nothing must tempt us to obey; no matter if they send volleys aboard. The distance is too far for them to do much damage; and I hear they are as a rule pretty punk shooters."

Felipe may hardly have known what that word meant, but he could give a guess.

"But sometimes, young señor, they even have cannon!" he remarked.

"You don't say!" ejaculated Andy, in new alarm; but he quickly caught himself, and went on. "Let 'em try it then. We'll just shut off the searchlight, and take our chances for a while with the old floaters on the river. Then perhaps they won't see anything to bang away at. Anyhow, just make up your mind, Felipe, we don't haul in, not while the blessed old tub keeps above water."

"It is good to hear such brave talk," said the old pilot, chuckling. "Me, I will keep going straight ahead, no matter what comes, until I have the order from you to turn the boat. Yes, let them shoot, señor. After all, I do not believe they could hit the side of a palace in this dark."

All the same Andy thought he ought to arouse his cousin, and make Frank aware of the new threatening peril.

On hearing the facts, Frank agreed with all the one on guard said, even to being ready to extinguish the useful searchlight when the critical moment arrived.

"We'll just have to take chances, that's all," he declared. "Even if we came swat up against one of those floaters, that's no reason we'd be snagged and sunk. They make these boats pretty strong, over there across the big pond, and I guess our hull could stand a hard punch."

"Yes," remarked Andy, feeling easier, now that Frank was on deck, ready to take matters in his able hands; "and after all, it's a choice between two bad things, in which we pick out the lesser. Hang the old insurrectoes, I say! Why can't they just pay attention to their own business, and let us two peaceful Bird boys alone?"

"Well," laughed his chum, "you know how it is yourself, when you want something pretty hard. And they've got the notion in their stubborn heads that if they only had a modern, up-to-date aeroplane, they could just make the miserly old government come to terms instanter. Don't blame them too much, Andy. Maybe you and I would do the same thing—if we were Colombians, and on the outs."

"Looks to me like there was something like a fire ahead, Frank!" declared Andy, right at that juncture.

"I say, you're on the spot every time, old fellow," observed the other, as he shaded his eyes to look. "There's a sharp turn ahead, where Felipe says we enter the narrow place. And I honestly believe they've got a bonfire burning on the right-hand bank."

"Then, after all, shutting off our bully little searchlight won't do us much good," complained Andy, regretfully.

"Don't you believe it," Frank hastened to remark. "A fire isn't going to reach all the way across the river, which is pretty wide, even at its narrowest part. And depend on it, our clever old wheelsman will keep just as snug up against the left hand shore as he dares go."

All the same, despite these assurances from his cheerful chum, Andy confessed to a secret feeling of apprehension as they drew closer to the point of land beyond which the danger possibly lay in wait.

It seemed to him that every conceivable species of peril threatened the sacred enterprise, upon which he had so eagerly embarked. From various sources did harm hover over their heads. And even though they passed safely through all these, there must be many more to come, after they had launched their little airship, and started to explore the strange regions of this tropical land.

"It's a fire, all right, Frank," he said, as they negotiated the bend, and opened up a new vista ahead.

"Yes, that's so for a fact," returned his chum. "And notice, will you, Andy, how old Felipe has managed to keep over well toward the port shore. He sized up the situation all right, and knew how to act."

"Yes, Felipe tells me he used to serve in the army. Many a battle he has been through, not only in Colombia, but in other countries as well. He was once something of a soldier of fortune. But where are you going, Frank?" as his comrade started to leave him.

"I must warn the crew to keep out of sight, or they may be hit, if there happens to be any shooting going on," called the other, over his shoulder.

He found that every member of the crew seemed to be awake, as if they had talked the situation over, and also guessed where the trouble would lie in wait for the venturesome young Americano señors.

So Frank gave his warning, and saw that they obeyed. While they were in his employ he felt a certain degree of interest in these ragged fellows, and did not wish to be held responsible for any damage they might receive, if inclined to be reckless at times.

When he once more reached Andy's side the latter was looking through a pair of marine glasses they had fetched along, thinking they would prove especially valuable in scrutinizing the country over which they might be passing in the aeroplane.

"They're our friends, the revolutionists, I reckon," he announced. "I can see several who carry big swords that dangle around their heels. And the common soldiers, while they have little if any uniforms, and some of them no shoes, seem to all have guns in their hands. Here, look and tell me what that is on the little rise. I'm afraid our worst fears are going to come true."

"Well, you're right, Andy," replied the other, after he had clapped the binoculars to his eyes. "That's a cannon, all the same, and they're getting ready to shoot!"

"Oh! my! It makes a fellow's flesh just creep, to think of being banged away at with a great big cannon!" declared Andy.

"This one isn't so very big, I think. And now we're nearly opposite where the fire burns. They're going to make a move to show their hand. Drop down flat on the deck, Andy—quick with you!" and Frank, as he spoke, set the example himself.

Hardly had the two boys thus thrown themselves down than there was a heavy boom, accompanied by a brilliant flash of fire from the shore.

The revolutionists had fired upon the little steam yacht!

CHAPTER XII : A GREAT SURPRISE
"Wow! now, what do you think of that?" exclaimed Andy, raising his head, just as one of the big turtles native to these warm waters might thrust his out of his shell.

"Why, that was only a warning to bring us up short, and pay attention!" declared Frank. "Because, as you saw, the ball splashed the water ahead of our bow."

"But Frank, we don't mean to head across?" cried Andy, getting up on his knees, the better to see.

"To be sure we don't. That was all settled long ago; and you notice that our good Felipe is still keeping her nose headed straight upstream. Now out goes the searchlight, just as we arranged. Wonder what they'll think that means!"

"Perhaps they'll believe they knocked it overboard with that shot!" suggested Andy, who could joke, even when facing troubles as thick as a sea fog.

"Listen!" Frank exclaimed, "there's a chap with a pair of leather lungs, shouting a lot of gibberish. I suppose he's demanding our surrender, and threatening to blow us to smithereens if we decline to believe him."

"One good thing is that each minute takes us further up the river, and every foot counts in this game of runaway. Already we're past where the gun stands; and those fellows are working like fun to get her turned around, so as to point after us. While they load we're doing more stunts. Yes, and Frank, we're leaving 'em in the lurch, I do believe."

"Sure thing," returned Frank, composedly, "only both of us want to duck when it looks time for the blamed old gun to bang again. They mean business from the word go, now, and will shoot to hit! By some accident it might run afoul of the boat, and splinters fly. There, get ready to drop, Andy! It's coming!"

It certainly was, for immediately another flash sprang up, accompanied by the same deep bellow, as the fieldpiece was discharged. No doubt, while it may have been rather out of date in pattern, the cannon was good enough to have done savage execution, handled by expert German or French gunners.

But there did not seem to be any such among the rag-and-bobtail army of the new aspirant for the presidency of Colombia. At any rate, the missile whizzed and whined past the retreating boat, missing her by yards.

"Bully!" shouted Andy, jumping up and cutting a few pigeon wings on the deck to illustrate just how pleased he was. "By the time they're ready to let her off again we'll be nearly out of range. And from the looks of the bank I feel pretty sure they never can catch up with us, toting their old gun along."

Three minutes later there came the third report, and they heard the ball pass high overhead, proving that the marksmen had entirely lost all traces of the boat and simply fired at random.

"That settles it," said Frank, decisively.

"Do you think so?" asked his chum, joyously.

"No question about it, Andy. Like the government official on the wharf at Barranquila, they realize that the game didn't work, and if they want to get us they'll have to lay some new plans when we come back again. But we're not bothering our heads about that, you know."

"Never even cut a chip off our boat!" declared Andy.

"Well, I'm going back and get the rest of my nap. Wake me up at four, remember. I want the last watch," and Frank dove within his stateroom with as much seeming indifference as though this thing of being fired upon with fieldpieces might be an everyday occurrence in his experience.

Morning dawned upon the Magdalena. Frank was on duty at the time and drank in the lovely picture. Birds flew overhead, cranes arose from along the shallows in near the shore, where they had been fishing for their breakfast, and there were many strange feathered creatures to be seen, such as the boy had never up to now set eyes upon.

Some of the crew were trailing fish lines astern and every now and then a prize would be hauled aboard, which later on might afford a meal for passengers and workers.

Andy soon made his appearance, the rising sun having sent a few slant rays into his sleeping quarters and aroused him by falling on his face.

"This is something like, eh, Frank?" he remarked, as he drew in a big breath of the bracing morning air.

"I should remark, yes," was the other's reply.

"We've apparently left all our dangers behind," Andy ventured. "That is, I mean there's little likelihood of our being robbed of our precious machine now, with both government officials and envious revolutionists left in the lurch."

"I was just asking Felipe and he says we shall have another day and night of bucking up against this nasty current. You see, Andy, it's on an unusually big bender right now, which makes it doubly hard to fight it."

"Oh, well, what can't be cured must be endured, I guess. So I'll try to take it as easy as I may and be thankful it's no worse," Andy replied.

The morning passed without any event worth mentioning. And all the while they kept steadily at the business of eating up some of the two hundred miles that Felipe assured them lay between Magangue and the city at the mouth of the big river.

Another thing was worrying Andy, however. He finally broached the subject to his comrade knowing that in this way he would get relief.

"That blessed old engine has been doing bully for a long time now, Frank, but judging from past experiences, she's due for another sulky fit soon. Whatever would we do if she let down all of a sudden, while we were right in the worst kind of a swift current? My! we'd be carried miles downstream before we could do anything."

"Oh, no we wouldn't!" remarked the other, smiling.

"Then you've been thinking it all over and made ready to offset a balk, I bet anything," declared Andy, with vehemence.

"Do you see that anchor forward?" asked Frank, pointing from where they stood on the raised deck aft. "Well, that's got a good long stout chain attached and is placed where a kick will send it over. Notice old Quita squatting close by? Think he's taking a snooze, he seems so quiet? But all the time the old chap's on the alert, and he has his orders, too."

"To upset the anchor over the bow, you mean?" asked Andy.

"Just that," came Frank's reply. "If anything happens to the machinery you'll hear a series of quick whistles from Felipe. The boat won't even have a chance to lose headway before over plumps the big mudhook, and we'll just take a rest out in the river until repairs can be made again by Engineer McClintock and his assistants."

Andy looked at his chum admiringly.

"Blessed if you don't just think of everything!" he said; "and get ready long before it happens. However do you do it, Frank?"

"Oh, it's easy, once you make up your mind," laughed the other. "I took to it long before this new Boy Scout movement started. You know they've got as their leading motto the words: 'Be prepared.' And there never was a better slogan ever given to boys. Think how many things might be avoided if we were always prepared."

"Yes, I've given the subject much thought," grumbled Andy; "but somehow I seem to slip up when it comes to the critical time. I stay awake eleven hours, and just when I doze off in the twelfth watch the blamed thing happens! It's always that way, seems to me. How can a fellow stay awake all the time, tell me that?"

"Oh, rats! There's no need of that. Just fix things so you'll be aroused when it comes along, and be ready to turn the tables."

So they talked away into the afternoon. The engine seemed to be on its best behavior. McClintock, the Scotch engineer, who was the only foreigner aboard besides the boys, reported that he was beginning to have more faith in the machinery. The work of the last twenty odd hours had certainly been a pretty heavy tax on it and everything seemed to be going like clockwork.

"I only hope it'll keep up, then," said Andy. "One more night is all I ask. Then Felipe promises to have us at our journey's end, when I can see and talk to the very man who picked up that wonderful little parachute, with its message from the unknown valley among the cliffs. I wish the time was here right now."

"Felipe, by the way, is taking his rest now," said Frank, after a little time; "for he expects another night on duty. We still meet many tree trunks sweeping down on the current. The man at the wheel has to keep on guard constantly. Look at that tremendous one, will you, Andy? And just notice how dense the forest is ashore around here. How any one can get around at all beats me. I should think they'd have to keep their machetes busy all the time cutting the matted vines away."

"I understand they do," the other went on. "And I rather guess that there's hardly a country under the sun where an aeroplane would be of more real benefit than right here in the tropics. Think of avoiding all that tangle—of floating along, a mile a minute if you wanted, far above the tree tops and away from all such a muss."

"You're right," agreed Frank, fervently. "And it's the only way any one could ever hope to discover this strange prison of your father. From a distance of a thousand feet we can have a big range of vision. With our good glass it will not be hard to discover the cliffs, if only we figure out in which direction we can have the best chance. And I think I've got a scheme ready to manage that."

"I depend on you to do it," said Andy. "Alone by myself I would simply despair of ever learning anything worth while. But while you are along I just feel that we're going to succeed."

"I ought to thank you for saying that, but I won't," Frank declared. "Because it makes me tremble for my reputation as a prophet."

"But you have seen nothing to make you less confident, I hope?" cried the other.

"To be sure I haven't," replied Frank, readily enough. "On the other hand, I ought to feel better satisfied than ever, because we've managed to outwit every cause for trouble that has cropped up this far. We'll get through this coming night without accident, because we're ready for anything. Then, when another day dawns, we'll haul in at Magangua, to hunt José Mendoza up and hear what he can tell us about the parachute that fell among his cocoa trees."

"Hark! what ails the men forward?" exclaimed Andy just then.

They sprang to their feet and rushed to where they could see what was going on.

"Perhaps a mutiny!" exclaimed Frank, who could not tell what queer thing was ever going to happen down in this land, the people of which were so different from all whom he had ever known before.

Andy uttered a low cry of alarm and began to fumble for the revolver Colonel Josiah had made him promise to always carry on his person, once they reached the country of revolutions.

The first sight they obtained told them that something unusual had indeed happened. A number of the native crew were in range of their vision, but every man had fallen flat on his face and seemed to be cowering there as if afraid.

"What in the dickens is it?" gasped Andy.

"I don't know. They are a scared lot, that's sure! Perhaps they saw a sea serpent alongside! It couldn't be that a jaguar has boarded us. No, look at old Quito, how he lifts his head and takes a terrified look! Why, he seems to be observing something up above in the heavens as sure as you live!"

As Frank shot out these words he, too, bent his head back to scan the brazen sky above. A cry broke from his lips.

"Why, what under the sun does it mean?" exclaimed Andy, who had also turned his eyes heavenward to discover a strange thing speeding over the tops of the trees, one, two thousand feet high, and at the same time there came to his ears a familiar throbbing that could have but one meaning.

"An aeroplane!" he burst forth in thrilling tones; "and the sillies down there think it's just a frightfully big bird about to carry them off. Hey, Frank, perhaps the government has got one of the new contraptions after all!"

"Go slow," said Frank. "Suppose you look a bit closer, my boy. Isn't there something familiar about that same craft up yonder?"

"It's—it's a biplane, Frank!" gurgled Andy.

"Yes, and one you've set eyes on before, too, old fellow. It belongs to—"

"Perc Carberry!" burst from Andy's quivering lips, as he continued to stare, as if almost unable to believe his own eyes.

CHAPTER XIII : THE "CRAZY-BIRD"
"Yes, Perc Carberry and his crony, Sandy Hollingshead!" declared Frank, positively.

"But, it seems impossible! All these hundreds and hundreds of miles away from old Bloomsbury and Perc Carberry floating over us! Sure I must be dreaming, Frank!" stammered the other, still gaping up at the rapidly passing aircraft.

"No, you're just as wideawake as ever you were in all your sweet life," said Frank. "Take a better look, Andy; don't you see now that it's the same biplane we raced with the day Sandy dropped that bag of sand, hoping to break our winning streak in the dash for Old Thunder Top?"

"Anyhow it's a ringer for it, I give you my word!" muttered the stunned boy.

Frank, with an exclamation of impatience, sprang forward and snatched something up that had just caught his attention. This proved to be the fine field glasses that had been brought along on the adventure.

These he clapped to his eye, and as they were already fitted and adapted to his sight, he lost not a second in covering the passing aeroplane.

"Look for yourself, my boy!" he cried, handing the binoculars over to Andy, who hastily raised them.

"Well, I declare, that settles it!" ejaculated that individual immediately.

"You recognize them, then?" asked Frank.

"It's Perc as sure as thunder. I can see him plain. The other is just out of line, but there's something about his figure that makes me ready to say it's our old friend, Sandy," Andy replied, amazement still gripping him tightly.

"Well," Frank observed, "after all, the only queer thing about it is our glimpsing them so soon. We knew they were headed down this way somewhere, but they made quicker time than our best. And just to think that they're the first to fly an aeroplane along the region of the Magdalena."

"Huh! they beat us up in the air that other time, yet when it came to a showdown, we left 'em at the stake!"

Andy was beginning to recover his breath, and with it came renewed confidence.

"Do you see anything in the actions of Perc that would indicate he had recognized us aboard this boat?" asked Frank, for the other still kept the glasses glued to his eyes.

"No, I don't," replied Andy, presently. "You see they're awful high right now, and without glasses they could never make us out down here."

"I guess you're right," was Frank's decision. "Perhaps it's just as well, for there's never any telling what mean trick those fellows have got up their sleeve."

Andy suddenly removed the glasses and a sudden pallor seemed to cross his face.

"Oh, Frank!" he cried, "you don't believe they'd ever be so wicked as to try and stop us from searching for my father, do you? Bad as Perc Carberry is, I can't just believe he'd ever do that."

"Well, I hope not," returned the other, but there was a trifling vein of doubt in his voice, for he had long ago ceased trying to figure to what depth of depravity those two schemers might descend.

"But where do you suppose they came from right now, Frank?"

"That would be hard to tell," Frank replied. "The first you saw of them they were sailing up over yonder. Then the chances are they have quartered themselves at some town, perhaps on the river, and that this is just their first flight—a sort of look over the country."

"Yes," said Andy, "they're circling right now as though they mean to head back again."

"Well, you can't blame them much," Frank ventured, watching the actions of the aviators above with keenest interest. "Night isn't so very far away, and I should think a fellow would hardly feel like being caught out after dark down here in an airship."

"Well, hardly," Andy smiled. "Curfew must ring for us every time. Fancy dropping plump in the middle of such a jumble of forest as that is yonder, and I bet you it's just cram full of snakes, jaguars and everything else that would want to snuggle up to a poor birdboy dropped out of the clouds. Me for daylight when I go sailing down in this blessed region."

"Look, the men are beginning to recover from their fright," remarked Frank in low tones. "There's old Quito sitting up now and commencing his everlasting jabbering with the others. See him point to the biplane and then to us, Andy."

"Say, the sharp old coon is getting a pointer on us. He's telling his chums right now that the thing we've got stored away in the lazerette is just such a big bird as that going away over yonder. Am I right, Frank?"

"You never said a truer thing. But they were certainly a badly rattled crowd for a time. And we can hardly blame the poor fellows, for what could they think but that it was a tremendous bird of prey, looking them over with an eye to grub?"

Frank laughed a little as though the recollection of the fright of the crew would always seem more or less ludicrous.

They sat there and watched until the mysterious biplane had completely disappeared in the hazy distance that marked the coming of evening.

"You don't think then," asked Andy, when it had vanished from view, "that Perc and his biplane could have fallen into the hands of the Colombia authorities and that they're using it for scouting to learn the movements of these ragged revolutionists?"

"No, I don't," was Frank's quick response. "You said you could positively make out Perc at the wheel, and I'm almost sure it was Sandy with him. They must have slipped into the country without giving their secret away. Trust sly Perc for knowing how to do that sort of thing. He never goes around with a brass band, telling what big things he has on tap."

"That's right. Why, just think, not a soul knew about his old biplane until he had it about done. We were working in the open almost, telling much of our plans, but Perc pretended to be mighty envious and asked questions, when all the time he was meaning to beat us out. Of course, he could get into Colombia without giving his secret away. You don't need to tell me, Frank, you're surprised at that."

"No more I am. But there goes the sun. How quick it seems to drop out of sight down here," Frank remarked.

"Sure," laughed his cousin, "but all the same I fail to hear any bang. You remember the Irish immigrant who heard the sunset gun at a military post in America for the first time and on being told that it denoted sunset, innocently exclaimed, 'Sure, the sun niver goes down in Ould Ireland wid a bang like thot!" But already the dusk is creeping out of the dense woods on to the river. And I'm getting hungry. It must be near supper time. I wonder what the folks up home are doing right now?"

"Just what we are, likely—waiting to hear a welcome sound that will call them in to feed. And there comes little Pepito to blow the conch shell that he uses for a dinner bell. Come, Andy, get a move on you. Another night and then we are going to do business at the old stand. It will be just fine to soar above this strange country and see for miles and miles—mountains, valleys, rivers, tropical forests, and everything that we've never looked down on before."

The two young aviators went into the cabin for supper. They fared very well insofar as food was concerned. Of course, both of them missed the home cookery. The native who attended to this part of the program did his level best to please, and he certainly had plenty to work with. But his Spanish style of serving even the most ordinary dishes of tinned meats with a dash of garlic was beginning to pall upon the taste of the American lads.

Frank had even started to show him other ways of cooking, and they had hopes of converting the cook by slow degrees.

The night was in one sense a repetition of the preceding one. True, they would not have to consider being halted by a gathering army of the revolutionists, and that was a comfort all around. At the same time Frank deemed it necessary that he and his cousin keep watch. And Andy was perfectly willing to sacrifice some of his personal comfort for the sake of insuring the safety of the precious aeroplane.

It proved just as well that they had so determined. During Frank's second term on guard and somewhere around four o'clock, while darkness covered the land, he thought he caught a glimpse of a shadow crossing the deck, headed in the direction of the lazerette.

He had been lazily reclining on a soft cushion made of several blankets and looking up at the silvery stars, but immediately he became fully aroused. This might mean danger in some shape toward the aeroplane. And no matter, it behooved him to investigate.

So he softly arose to his knees and crept after the shadowy figure.

Cautiously he approached the place where the door belonging to the storeroom was to be found. As he advanced thus he could occasionally catch a peculiar clicking sound, which he believed must be made by some one trying to pick the lock!

The engine of the boat kept up considerable of a racket as it steadily worked along without the dreaded hitch. Besides, there was always more or less splashing of water against the sides, as they pushed against the swift current of the Magdalena. All these things combined to muffle the clicking sound frequently, yet during little lulls Frank could catch it again.

The tumult also served to deaden any shuffling he may have made while creeping toward the lazerette door, and for this Frank was thankful.

It was very gloomy here. A hanging lantern some distance away only served to accentuate the gloom apparently. Still, by straining his eyes, Frank believed he could just manage to make out a stooping figure at the door. Yes, he was certain that it had just moved, and now the peculiar clicking was much plainer.

When it stopped he remained perfectly motionless, nor did he again commence his creeping forward progress until it started once more.

Frank no longer had the slightest doubt concerning the cause of that suspicious clicking. One of the crew was endeavoring to force an entrance into the locked lazerette, doubtless with the intention of destroying the valuable aeroplane. He might be in league with the revolutionists and in this way hoped to prevent the government from eventually securing possession of the machine which would put the insurrectos out of the running.

But Frank had conceived another idea. He now believed that his fellow might have been sent by the crew to destroy the "crazy-bird," as they undoubtedly considered a contraption that could soar through space as fast as the fleetest condor.

No matter. It was his business to put a sudden stop to the action. And while doing so he must not be too rough in his dealing with the fellow, lest the entire crew rise in revolt.

When he had reached a point that allowed of a leap, Frank suddenly sprang forward. He did not know just what he might be up against and had even taken from his pocket the splendid new pistol which Colonel Josiah, himself a world traveler, had insisted upon giving each of his boys before they started on their trip south.

"Surrender!" cried Frank, believing that the very sound of his voice would do much toward frightening the would-be traitor.

But he hardly expected such a tremendous upheaval as followed. The man, believing that possibly the "crazy-bird" had broken out of its cage and was about to carry him off in its gigantic beak, gave a shrill scream of terror, and bouncing up, broke the slender hold Frank had secured upon his person.

Not to be outdone, Frank, recovering, chased after him. He believed it his duty to at least learn the identity of the rogue, so that he might understand just how deeply the conspiracy had taken root in the crew.

Between himself and the hanging lantern he could make out the fleeing figure of the fellow, and hot in pursuit he followed as fast as his feet would let him. The man undoubtedly heard him coming, for, if anything, his fright increased. Out upon the open deck they flew, Frank just a few feet in the rear. He had even stretched out his arm and touched the garments of the runner, when with a screech the fellow made a furious plunge straight over the side of the boat.

He evidently chose to take chances in the swift current of the Magdalena rather than trust himself in the power of the unknown pursuer, which doubtless he believed to be the dreaded "crazy-bird" that had been confined in the box cage!

CHAPTER XIV : THE AIRSHIP LAUNCHED AT LAST
Frank came near following after the unknown member of the crew, when the other made that flying leap over the side of the boat. Not that he wanted to take a bath just then, but his forward progress had been rapid, and he only saved himself by banging up against the taffrail, which was unusually high for so small a vessel, and holding on sturdily.

He had heard the splash as the fellow reached the water. Doubtless he was a good swimmer, as about all these natives seemed to be, and barring his falling a prey to some loitering alligator or other reptile, he would be able to gain the neighboring shore further down.

At any rate it was folly to think of looking for him.

"What's all the row?" cried Andy, as he came plunging forth from his stateroom.

Some of the crew were even then looking over the side, and Frank imagined they could give a pretty good guess as to what it meant. But he heard not a word from even old Quito, and while the absence of a man must be noticed in the morning, there would probably be no complaint.

When Andy heard about the attempt to injure the monoplane he was in a tremble.

"Did you ever?" he exclaimed. "Why, it seems as though everything just wants to knock us. When we give the government officials the merry ha! ha! and even slip past the revolutionary army, after being bombarded by their old cannon, here even our own men want to smash our precious aeroplane, under the belief that it's an evil bird, come to bring bad luck to the people."

"Better go back to your bunk and forget it," remarked Frank, who was tenderly rubbing his elbow where it had come in contact with the hard taffrail at the time he stopped so suddenly, balking at a bath.

"Me? Not on your life, Frank!" declared Andy, with much emphasis. "I'm going to take a blanket and just lie down in front of that blessed door. Nobody can get in then without walking over my body. And if I catch a fellow trying it on, believe me, I'll give him something he won't forget in a hurry. It'll be touch and go with him, I bet you."

Which he actually did, much to Frank's secret amusement, camping out there on the floor as close to the locked door as he could get, and bracing his back up against the same.

But then, fortunately, morning was not so far away and Andy would have only a couple of hours, more or less, of his self-imposed labor.

They knew that if the pilot of the river expedition said truly, they must even now be drawing near the town of Magangue. Possibly it would break upon their vision with the coming of dawn.

Frank himself had no more intention of retiring to his bed than had Andy, but continued to keep watch and ward until he saw the first peep of daylight over the port side of the vessel.

Then he communicated the glad intelligence to his chum, and together they stood there, watching the slow unfolding of dawn. From an ashen gray the sky began to be marked with brighter hues; pink flushes traveled along in lines that centered in the spot where the sun would presently appear, and the gloom of night retreated once more back to its hiding places among the mountain passes.

"There's the dinky old town!" cried Andy, pointing with trembling finger.

"It is and no mistake," replied Frank, himself experiencing a sensation of considerable relief, for at times it had seemed more than doubtful whether the little expedition could ever overcome the many difficulties that beset its passage up the swollen river.

And so they came to land just as the glorious sun showed his smiling face. Andy declared that this was a harbinger of good luck, and his cousin chose to readily agree with all he said, for it pleased him to see Andy look more like his old self than he had been for many a day.

"Remember, only one of us ashore at a time until we land this cargo," remarked Frank, as they came to bring the boat to the bank, where a group of natives waited to see what it all meant, surprise written largely on their dark faces.

"That's right," responded the other traveler. "But I'm going to have the aeroplane carried out on deck at once, so it can be taken ashore as soon as we find where we are at. What we want first of all is to hear about our friend, Carlos Mendoza, the cocoa planter. Perhaps he lives miles away and we'll have to get some sort of conveyance to tote our machine out to his place."

"Yes," observed Frank, "I've been laying out plans along that line. If you don't mind I'll drop ashore while you're having the crates brought on deck and make inquiries. Even away down here in this wilderness money talks. Colonel Josiah told us it did for him in the heart of darkest Africa, you know. And a few bolivars will hire all the help we want."

Andy was perfectly agreeable that his companion should have taken upon himself the task of engineering things.

"You can always discount me when it comes to bargaining," he said, laughingly; "so go ahead and fix things to suit yourself, Frank."

Upon reaching shore, Frank, who had taken old Felipe along with him to serve as interpreter, found that Carlos Mendoza had his home just on the border of the town, though it was a little distance away. He soon made arrangements for hiring a native cart to be used in transporting the precious aeroplane.

In less than half an hour they were on the way. The boat had been left in charge of McClintock, the Scotch engineer, who would make sure that the crew remained on board or lost the wages coming to them.

Both of the boys were so excited that they paid little attention to the strange scenes which now surrounded them in the valley town far back in the interior of tropical Colombia. Indeed, one might even have suspected that they had always been accustomed to living in a region where all manner of tropical fruits abounded, coffee and cocoa were raised as crops, and birds of brilliant plumage flew overhead.

The truth of the matter was, they knew they would presently come face to face with the planter who had actually picked up the little messenger sent out of his cliff bordered prison by Professor Bird. And this fact set their nerves to trembling with eager anticipations.

In due time the cart on which the aeroplane had been secured, together with the luggage which the young aviators wished to carry along, drew up before a long, low white building, back of which could be seen orange trees and other evidences of a real tropical home.

Their coming must have been noted, for a gentleman was advancing from the grove at the rear. Señor Carlos looked surprised at seeing the caravan bringing up before his door, but that was as nothing in comparison with his amazement upon learning how one of the two young Americanos was the same Andrew Bird to whom he had desired his friend, Señor Almirez, to forward the strange message picked up in his cocoa grove one day several months back.

The boys had learned from Señor José that the owner of the plantation could understand English and even speak it fairly well. Thus they had no need of fetching Felipe along to act as interpreter.

"Oh, please first of all let me see the remains of the silk parachute that was attached to the bark letter!" said Andy, after they had conversed for a short time and some of the planter's hired servants had unloaded the boxed aeroplane, which was stowed away in a place of security.

Doubtless the planter understood the reason for the boy's solicitude. He immediately took them inside the house and in another minute had thrust into Andy's eager hands a discolored piece of silk, such as is used in the making of balloons.

Nor did either Frank or the Colombian planter think it strange that the boy should press the token again and again to his lips, while tears ran down his face. They could understand the feelings that filled his heart, and no matter what the nationality may be, the honest love of a lad for his father cannot but provoke admiration and respect.

"And now," said Frank, presently, when his cousin had in a measure recovered from his first emotion, "will you tell us, Señor Mendoza, just how you found this strange communication? I hope you remember the exact day, because it is of the greatest importance to us that we learn, as near as possible, from just what quarter it came."

"Si, señor, I understand that," replied the planter, eagerly, his dark face aglow with enthusiasm. "I made note of the day in my diary, also the fact that it was the third day in succession when the wind blew direct from the south, with just a faint turn to the west."

"Splendid!" cried Frank, turning to give his chum a reassuring nod. "What did I tell you, Andy? The forethought of Señor Carlos has made our task much easier. There can be little doubt, then, that the hot air balloon must have started in a region that lies almost due south of here, possibly with a slant, as he says, toward the south by west quarter, as a sailor would call it. And now, señor, can you tell us just where a direct line that way would bring us?"

"First over the lowland and the forests. Then, if you go far enough amigos, it is the Sierra San Jeronimo mountains you would strike," replied the planter.

"Yes, I remember them on the map we have, and that corresponds exactly with all I had in my mind," Frank observed, his forehead wrinkled with serious thought.

"What sort of country is it up in those mountains?" asked Andy.

The planter shrugged his shoulders.

"That I am unable to tell you, amigos, since I have never been there. From all I have heard I believe it is one of the wildest and most inaccessible regions in all our country. Lofty peaks warn back the most daring explorer. Few have ever ventured to attempt to go among them. Some never came back, they say. The superstitious declare those mountains are filled with evil things. Nothing on earth could tempt one of my peons to accompany an expedition thither."

"Then it is lucky that we will not need any assistance in our adventure," remarked Frank. "With an aeroplane one may be independent of help. And now, Andy, what shall we do? It will take us the better part of the day to assemble our little flier and get things ready for an ascent."

"That means another horrible night of waiting before we can make a start," said Andy, looking quite forlorn.

But he soon understood that it could not be helped. Both boys were presently hard at work, with the deeply interested planter watching every move. All the while they conversed and the subject of pretty much all their talk had more or less to do with the country, the peculiarities of climate, what sort of weather they might expect to have and dozens of similar matters.

Doubtless Señor Mendoza would like to hear of things connected with the great outside world, which he seldom saw anything of, but he realized that these would keep until after the brave young señors had completed their task of humanity.

Before evening came they had everything arranged to suit the critical Frank. Both boys were pleased to find that the monoplane had come through its long journey without any damage having been done.

That night they were uneasy about the precious airship, and at their request the planter had their beds made up in the shed where the "Bug" lay. But there was no attempt made to injure it in the least.

Then came the morning. Andy could hardly eat a bite of breakfast, for the eagerness that possessed his soul. Every servant on the plantation had gathered to look with awe upon the wonderful bird-like machine, on which, it was whispered, these two venturesome young Americanos meant to soar among the clouds.

Finally the last word was spoken, the planter shook hands with each of his visitors, Frank turned on the power, the aeroplane with the motor exhaust sounding like a volley of musketry started to run along the level ground, and presently, to the consternation of the entire gathering, began to climb upward, just like a creature of magic!

Cries of awe arose from scores of throats and to a man the peons threw themselves flat on their faces, hardly daring to look at the terrifying spectacle.

CHAPTER XV : AN UNPLEASANT SURPRISE
"At last, Frank, we're on the move!"

"Yes," replied the one at the wheel, as the cries and cheers from below were drowned by the volleying motor explosions; "and did you see the señor kissing his hand after us, while his men were flat on their faces?"

"It was a queer sight," Andy remarked. "And no wonder these ignorant peons call our little monoplane a 'crazy-bird.'"

"Look down now. Just to think of two Yankee boys being allowed to swing over a tropical scene like that," said Frank.

Both of them were deeply interested. In the valley they could see the little town, with the river stretching off toward the south. Then there were the patches of tropical vegetation, the fruit trees and the cocoa plantations—all those interesting things which neither of them had ever set eyes on before.

Señor Mendoza had told them how the coffee was grown upon a certain part of the mountain slopes, since it did not do well in the valleys, preferring a higher altitude.

They followed the course of the river generally, intending to cover possibly something like eighty or ninety miles before trying to comb the land from side to side, in the endeavor to find the strange cliff enclosed valley.

From time to time Andy would call the attention of his aeroplane chum to some striking feature of the landscape far below. The little Kinkaid motor was humming merrily, without ever missing a stroke, and Frank, having the utmost confidence in its steadiness now, after so many trial spins, could take a few seconds at a time to observe these things.

"When we've gone something close on an hundred miles direct," remarked the pilot of the craft, presently, "I think we'd better make a descent, if given the chance."

"You spoke of that before," remarked his companion, anxiously. "What is the reason for doing it, Frank?"

"Oh, nothing serious," replied the other. "We will then be at the parting of the ways, you know."

"You mean we'll be about to leave the river that will have been our guide up to then?" asked Andy.

"Yes," Frank admitted. "And from that time forward we must simply depend on our judgment for everything. In that event it might be well if we looked over the entire plant, to make sure everything was in apple-pie shape."

Andy breathed freer.

"Oh, I agree with you there," he hastened to say; "and I'm glad you hadn't any more serious reason. But did you ever see such a picture in all your born days? Just look at the forest bordering the river. Think of trying to push through such a dense mass of over-grown jungle. And I bet it's just full of snakes, poisonous spiders, lizards and all such things."

"Not to mention such trifling citizens as jaguars, ocelots, tapirs, alligators, crocodiles and their kind," laughed Frank.

"Ugh! what lucky fellows we are to be away up here, where we can skim along at the rate of thirty miles an hour easily, without half trying, and snap our fingers at all those things. I tell you, Frank, this aviation business is the greatest thing that ever came down the pike."

So they continued from time to time to converse as they kept pushing along, following the winding course of the swollen river that could be plainly seen below, between its banks of forest.

Frank did not soar high at this time. There seemed no need, and besides, both of the boys were deeply interested in watching the various changes that kept taking place in the checkerboard landscape below.

Several times during the first hour they passed over hamlets or villages. On such occasions it was ludicrous to observe the excitement that occurred. The Bird boys would not have been true to their nature had they not enjoyed the tremendous sensation which the sudden and unheralded appearance of the aeroplane caused in these river settlements.

Loud shouts floated up to them that constantly grew in volume. Men yelled, women and children screamed. Many fell flat on their faces; others tried to conceal themselves, as though they belonged to a covey of wild ducks over which a hungry eagle hovered, picking out his contemplated dinner.

And the last thing Andy would see, as he looked back, would be wildly running figures gesticulating furiously and evidently next door to crazy with excitement. Apparently these natives believed that the aeroplane must be a visitor from another world, or else some monster bird of a family long understood to be extinct.

The second hour had nearly ended and everything seemed to be moving along smoothly. Frank saw not a cloud on the horizon thus far. Surely this augured well for the ultimate success of their strange expedition.

Suddenly he heard Andy give vent to a cry of alarm.

"What is it?" he demanded, quickly.

"Turn her upward, quick! They are going to shoot at us!" shouted the other.

Frank instantly started to obey, and while their forward progress still continued unabated, the aeroplane commenced to head toward a higher altitude.

Immediately he heard the dull report of a gun from below. He dared not bend his head to look, since all his attention was needed to take care of his machine at such a critical moment. But the whine of the bullet as it passed close by was very plainly heard.

Then came other shots, many of them, and the air seemed full of strange hissing sounds. Twice Frank felt a slight shock that told him some part of the aeroplane had been struck by one of the flying missiles. His heart seemed to jump almost into his mouth, as he trembled for the result. But nothing happened. The motor kept up its insistent humming, and there was not a quiver to indicate that a vital part of the monoplane had been injured.

"Andy, are you hurt?" he called, after the volley had ceased, the marksmen below having evidently exhausted their ammunition.

"Only a scratch," came the reply. "Hardly drew blood. Think a splinter from the wood where a spent bullet zipped past must have hit me. It's all right, Frank! We ran the gantlet just fine. But all the same I guess it would be better for us to keep a little higher after this."

"Did you make them out and were they government troops, do you think?" Frank asked, for though he managed to turn his head, already had they made such speed that only the interminable forest could be seen in their rear.

"No," returned his comrade. "I just reckon it was another camp of these insurrectos. You remember the señor said there were apt to be more than one crowd of them up the river. It's the only way to get in and out of this country, and everything that happens has to count on a water route. I guess the Magdalena is about the same to this part of Colombia that the old Nile is to all Egypt."

"Well, it was a narrow escape, all right," Frank declared. "I don't just like the sound of those bullets all around when you're six or eight hundred feet up in the air."

Andy had recovered from his recent fright by now and could even laugh.

"I should say not," he observed; "especially when you know that one little clip on either wing would upset us like a stone. Excuse me, if you please. I'll never be fully happy when flying until we invent some sort of little parachute that in case of a drop will give a fellow a chance for his money."

Another hour passed, when Frank declared they had now reached the point where a descent would be advisable in case they found an opening that looked suitable.

"There are the mountains over yonder on the right," he said, "and from now on we had better begin to scour the country, covering every mile just as though we had a comb and meant to explore it all."

The chance to drop came presently, and as the opening proved everything they could desire, a landing was made without the least trouble. Here they rested and partook of a light lunch, having brought plenty of provisions along, together with a gun of the latest repeating type, with which Colonel Josiah had presented them.

Frank, upon looking the aeroplane over a little later, discovered that he had been wise in deciding to make a halt. There was need of some attention. Certain parts had become weakened by the strain, either in the long voyage and handling on board the steamer, or else in this new flight.

He was determined to be thorough in all he did, and this consumed more or less time, so that when he finally pronounced the monoplane in perfect condition the afternoon was half gone.

Still, they must go up and put in an hour or two searching. Andy was too wild with impatience to hear of anything else, and Frank saw no reason for not complying.

"But we must be sure to get down again before night comes," he remarked, after they had made a successful rise and were speeding above the top of the thick forest. "If we should be caught out at night I rather guess it would be a serious piece of business." And Andy agreed with him.

For quite a time they soared aloft, Andy using the binoculars almost constantly, watching the country below and occasionally sweeping the distance.

Frank was thrilled to hear his chum suddenly give utterance to a cry, but it was more of amazement than delight that gave birth to this ejaculation.

"What is it now, Andy; more insurrectos?" he demanded, ready to manipulate the planes and strike for higher regions.

"No, no, not this time," came the quick reply; "but Frank, as sure as you live, there's that plagued old biplane just rising up yonder a mile away. And somehow I seem to feel that it spells trouble for us."

CHAPTER XVI : THE AIR CHASE
One hasty glance told Frank that there could be no mistake. Only too well did he know the construction of that same biplane that had in the near past competed with them for honors in the race for Old Thunder Top's crown.

"You're right, Andy," he said, earnestly; "and it seems to me they're heading for us right now. What do you make them out to be? Can you see who is handling the wheel? Is it Perc Carberry?"

"Yes, I'm dead sure of that; but Frank, there's somebody else with him!"

"Sandy?" asked his chum.

"No, it can't be. There, I had a good look at him, and Frank, he's got a beard! It's a man!" answered Andy, in tense tones.

Frank's first action was to move a lever that would change their course and place the biplane directly behind them. His next was to throw on more speed, so that the faithful little motor started to humming with the old-time rapidity that reminded Andy of the occasion when they put it to its best efforts in order to rush ahead of their rival of the air.

"Then we must guess from that Perc and Sandy have fallen into the hands of the rebels, since there are no government troops up here, the señor said," he observed, presently. "Are they gaining on us now, Andy?"

"I don't think so," replied the one who held the glass, "though Perc seems to be getting a whole lot of speed out of his Gnome engine right now. Reckon he must have overhauled it, or else found some way to put her up another notch."

"How strange to think that our old rivalry is being renewed away down here in this country, thousands of miles from home," remarked Frank, after a while.

"Huh! seems to me there would be something doing if you happened to run across Perc Carberry at the other side of the world," declared Andy.

The race kept up for some time, neither seeming to gain to any appreciable extent. Of course both boys were keyed up to a state of intense nervousness. Passing through the air at this fearful speed fully five hundred feet above the ground was surely enough to excite them. One little accident and they would hardly know enough to give a single shout of horror before the end must rush upon them. And yet Frank appeared as cool as though sitting beside a camp fire, laying out some contemplated air cruise on paper.

Andy was full of complaints.

"Aw, now, whatever do you suppose those measly old insurrectos want to chase us for in this style?" he growled. "We're attending to our private business and not bothering them one little bit. Why don't they leave a fellow alone? Goodness knows we've just got trouble enough on our hands without this."

"I don't know," said Frank, reflectively, "but I reckon they either want our monoplane or else believe we're in the employ of the government, and have been sent up here to spy on their movements. Anyhow, it seems plain that they mean to make a big effort to get us."

"Which they won't, if we know it!" cried Andy. "But see here, Frank, that chap is nervy, all right, going up with Perc and standing all this racket. A tenderfoot is generally rattled even with a slow flight. He seems to be holding out."

"I've been thinking about that," replied his chum. "And Andy, it looks to me as if that fellow must know something about aviation. If I could only glimpse him through the glasses I'd soon tell, for he'd show it by the way he sits there alongside Perc. A new beginner would be hugging the upright for dear life, and showing all the signs of fear."

"Yes, I know, because I did that same," answered Andy, once again raising the binoculars as he twisted his head around.

"How is it?" asked Frank.

"Not much signs of fright about him, as far as I can see," came the ready reply.

"Then make up your mind he's been up in an aeroplane before. Perhaps he's some French or German, who has thrown his fortunes in with the man who wants to sit in the presidential chair at Bogota, and in his own country he must have seen something of aviation. Oh, well, it doesn't make much difference to us. We just have to keep them at a distance and take our chances."

"But Frank—"

"Yes, I know what you're going to say, Andy; that night will soon be coming swooping down on us. That's so, and I'm sorry in one way, for it's going to be a tough old job finding a suitable place to fold our wings on in the darkness. But we're up against it good and hard, you see, and it's what you might call Hobson's choice."

Andy showed more positive signs of anger.

"What business have they got bothering us this way?" he grumbled. "Say, don't you suppose it would be all right for me to try a few shots at 'em with the fine Marlin repeating rifle we're carrying? Perhaps I could give 'em a scare anyhow and make 'em haul off."

"No, I wouldn't think of it," replied Frank, hastily. "You might cause trouble to our own delicately balanced little aeroplane by firing. And then again, what if you brought about an accident and sent them down to the earth like so many stones?"

"But you know those other chaps banged away at us and they didn't bother their heads a cent whether they upset our whole business or not," objected Andy, belligerently.

"Two wrongs never make a right, Andy."

"But when they opened fire on us," the other went on, complainingly, "that constituted a declaration of war, and so you see, we'd be quite justified in giving 'em back the same kind of medicine."

"You forget that one of those two in the biplane is a former schoolmate of ours and that perhaps he's just being compelled to chase us right now," said Frank.

"Think so, do you?" growled Andy, above the rattle of the exhaust; "well, I'd like to warrant you that Perc Carberry is grinning right now, because of the fright he thinks he's giving us. No, sir, he's only too willing to do anything to upset our plans. I know him pretty well, and I wouldn't put any meanness past that fellow."

Frank in secret did begin to feel more than anxious. The afternoon was almost over and the sun perilously near the western horizon. Too well did he know how rapidly darkness came after the disappearance of the king of day.

He bade Andy pay more attention to the lay of the country ahead of them.

"We're keeping well ahead of the biplane," he observed, "and there's little danger of their overtaking us. But in case they drop out of the race we must try and know something of the chances for a landing ourselves."

"Gee! it looks pretty punk down there!" admitted Andy, after he had carefully turned the glasses forward and down.

"That's what is bothering me," Frank said. "We've sure got to drop, sooner or later, because it would be utterly impossible for us to keep afloat all night. And if there happens to be no opening in that dense forest, how can we land?"

"Listen! as sure as you live they're trying to wing us with a shot!" cried Andy.

"Well, I wouldn't bother about that. The fellow only has a revolver, if I know the sound of one, and he could never reach us at this distance. It tells me that he's got to about the limit and that something is going to change pretty soon, mark my words, Andy."

Of course one of Frank's objects in saying this was to encourage his chum, for he knew that in all probability Andy was getting pretty close to what he himself would call a "blue funk."

Sure enough the reports continued until just six had reached their ears faintly.

"That ends it," observed Frank, complacently.

"And he never touched us," echoed his cousin, evidently with more or less relief.

"Now take a look back and see what they are doing, Andy."

"H'm! still coming right along at top-notch speed," replied the other.

"All right. There's going to be a change soon. Look down, Andy."

"Oh, Frank, what a dandy open space! If only that plagued biplane was in Guinea, how easy we could spiral down and make a landing there!"

"Yes!" said Frank, "And, mark me, that is just what they intend doing. As for us, we'll have to move along further into the wilderness and hope that another chance will come to let us out before everything is blotted from sight by utter darkness."

"Frank, they've just sighted the open spot!" cried Andy, a few seconds later.

"All right, what did I say?" demanded his cousin.

"They've given up the chase, sure!"

"And are about to drop down to make a landing for the night; is that so?" asked Frank, eagerly, for their own chances were getting poorer with every passing minute and secretly he was more worried than he chose to admit.

"Just what they're doing right now, beginning to spiral down. Perc and his old biplane weren't in it again with our dandy little Bug. There they go, Frank. Don't I wish we had as good a place to grab hold of the old earth!"

"Well," Frank continued, gravely, "turn around and look your prettiest for it, then. Don't let even a half way decent spot go by. Any port in a storm, the sailor says, and that ought to apply to the airship tar just as well. See anything yet, Chum Andy?"

"N-no, can't say that I do," came the reply, as the other eagerly bent his gaze on the tree tops that they were beginning to approach closer, for Frank had turned the lever of the deflecting rudder in order to start the monoplane earthward.

And the more they dropped the lower the sun seemed to get, until part of his glowing disc appeared to touch the horizon.

Already it was growing dusk below them, and the dense foliage of the interlocked branches of the trees seemed to offer an insuperable barrier to a successful landing.

CHAPTER XVII : THE CAMP IN THE TROPICAL JUNGLE
"Frank, this is tough luck!" Andy exclaimed, presently.

"Keep up your spirits, old fellow!" called out the other, cheerily. "Has the biplane succeeded in making a landing yet?"

"I guess so," replied Andy, moodily. "Can't see any sign of her back there. And besides, it's actually getting dark down below, even while we can see a bit of the sun up here."

"That's because of the contrast. I'll drop still lower, so we'll just clear the top of the forest. Then you won't need the glasses, Andy. Both of us must keep a clever lookout for a chance. Every now and then there happens to be some opening in the forest, you know."

"Don't I hope we find one, though," declared the other. "Oh, wouldn't it be too mean for anything, Frank, if we smashed the precious little machine just when we are at the last stage of our big undertaking? If I lived through it I'd be broken hearted sure."

"Look, then," said Frank, earnestly, "and you take the right, while I keep an eye on the left. Both of us can watch out ahead. If it comes at all to be of any use, it's got to be found inside of the next five minutes!"

"So soon as that?" echoed the other, in distressed tones. "Oh, I'm afraid we're in for the very worst experience we ever met up with."

"Ha! hold on, Andy. What's that dead ahead?" cried Frank, who suddenly decreased the speed of the little motor.

"It's an opening of some sort, though awful little!" ejaculated Andy. "We can never do it, I'm afraid, Frank."

"We've just got to, no matter what chances we take. Hold hard now and if you can jump out in time, help stop her before we wreck her against a tree."

Even while speaking the air pilot was starting to drop down. He had made a specialty of this part of the business, knowing how very important it must always be to aviators. The rise was nothing compared to the descent, for many a gallant aircraft has been injured or even wrecked by clumsy manipulation, want of room or some other cause while landing after a flight.

Andy gripped hold of an upright. He tried to see down into that little slash in the great forest, as though it might hold every hope connected with his fortunes and the success or failure of his mission of mercy.

"Oh, be careful, Frank!" he called, as they just barely missed the top of a great tree.

There was no need of saying this, as Andy ought to have known. No one could possibly be more careful than Frank Bird. And yet this was one of those times when daring had to go hand in hand with caution. The space in which they meant to try for a landing was so very small that it seemed necessary for the aeroplane to come down almost as lightly as a feather.

Fortunately the youthful pilot possessed a good pair of eyes. And the gloom had not as yet entirely blotted out all features of the landscape, now that they were so close to the earth.

Andy was holding himself in readiness. He knew that there would perhaps be an opportunity for him to drop to the ground and by pulling back, help to bring the little airship to a full stop before they banged up against a tree at the further side of the little glade.

Never before had Andy found himself compelled to do such a queer "stunt," as he afterwards termed it; but he was braced to exert himself now to the best of his ability.

"Jump!" shouted Frank, as they came roughly in contact with the ground.

And Andy went. He never knew whether he jumped purposely or lost his grip of that upright after the shock of the collision; but the next thing he realized he was straining himself with might and main to hold back the monoplane, already gliding along with sundry violent bumps, on the three bicycle wheels.

"Hurrah! What did I say?" cried Frank, as the aeroplane came to a complete standstill close to the other border of trees.

There was a frightened series of grunts close by and some big unwieldy animal went rushing away through the dense undergrowth, crashing along as though badly frightened at this queer thing that had dropped down from the sky.

"Wow! whatever was that, do you know, Frank?" cried the one on the ground.

"I don't know for sure, because I only had the least peep of something that looked like a small elephant making off," replied the other, also alighting.

Andy was already reaching for the repeating rifle, which had been securely fastened in the frame of the monoplane.

"But Frank, they don't have such things as elephants down in South America?" he expostulated.

"Sure they don't," laughed Frank, feeling particularly good over the grand success that had attended their perilous landing. "Nor a rhinocerous, nor a hippopotamus; but they do have the next largest beast, and that's a tapir. He's something like a big pig and not very dangerous, the señor said. That was what we frightened off just now, I reckon."

"Well, here we are on land again and mighty lucky to get down without some sort of a smash. Frank, you don't think anything was broken when we struck, do you?"

"Of course I can't say for sure, but I believe not. But all the same I must give a good look in the morning before we make another start," was the reply Frank returned.

"And now we're just got to stay here all night?" remarked Andy, who still held the gun in his hands.

"That isn't anything. We'll soon have a cheery blaze started that will keep the prowlers away, I guess. Get busy, Andy, and see what we can do. But we'll start it some distance away from our gasoline tank, remember."

"But won't they be apt to see a fire?" asked the other, as he reluctantly placed the rifle down and started to gathering wood, no easy task in the increasing darkness.

"Do you mean Perc and that other fellow?" Frank asked, with a laugh. "Oh, they're a mile or two off, and even if they could see the biggest of fires I'd defy them to get half way here if they took the whole night to cut their way through that mass of trailing vines and brush. Don't bother your head about that crowd, Andy. I hope we're done with them for good."

His reassuring words seemed to have considerable effect on his cousin, who up to recently had himself been a most cheery fellow.

"Well," he said, "we've sure got a whole bunch of gratitude on tap for the lucky way we dropped in here. Chances looked twenty to one it couldn't be done. And I'd like to wager that no other air pilot could have made the ripple so well."

"You're prejudiced, old fellow, because I'm one of the Bird boys," laughed Frank as he struck a match and applied it to the bunch of dead grass he had gathered in the spot selected for their fire.

It was a dozen yards away from the aeroplane and about the same from the nearest line of great bushy trees. Immediately the flame sprang up, dispelling the darkness to some extent.

"Shucks! but that makes a big improvement and no mistake," said Andy, stooping to drop some wood on the fire. "I always like to see what I'm doing. And more than ever when I'm in a strange place. Hark! what was that, do you suppose, Frank?"

A sound had come from the depths of the forest not unlike the wailing of a babe. Frank could give a guess what made it, but he did not immediately say so.

"Say, we must have landed close to some native shack, and that's a baby crying!" Andy declared.

"Hardly," came from Frank. "That's only one of our cat friends giving tongue, perhaps calling to his mate to come and see the funny objects that dropped from the skies."

"Wow! reckon now you must mean a yellow boy, a jaguar! I bet you, Frank, there's a heap of 'em around us right now. How do we know but what every tree hides one of the critters, watching everything we do? I can tell you right now that I don't wander far from this jolly little blaze tonight. And besides, one of us has just got to keep a grip on this gun all the time. I don't hanker after being carried away and made a meal of by a big hungry cat."

"Oh, the fire will scare them away all right, I believe. There isn't an animal that doesn't dread fire. Always keep that in mind, Andy, when trouble comes," said Frank, earnestly.

"I mean to," replied the other, as he once more started to pick up wood, but it could be noticed that while doing so Andy always kept on eye on the alert, as if he really believed what he had said about the chances of their being watched by an army of jaguars.

"There's another sort of cry, Frank," he remarked, presently.

"Yes, and although I couldn't say for sure, I believe it is made by a colony of monkeys, traveling through the woods at night," the other replied, after stopping to listen for a minute to the odd sounds.

"Monkeys!" cried Andy, smiling broadly. "Well, I declare I had forgotten that they have them all through the tropical regions around the Orinoco, the Magdalena and the Amazon. And so that's a menagerie traveling over the treetops, is it? Wish I could just get a look."

"Well, I don't think they're far away," remarked his chum.

"Not for me. I know when I'm well off. This camp looks good enough, without my wandering around in that awful place. Let 'em jabber, and the yellow cats snarl; but Andy Bird stays right at his fireside tonight."

"And I guess you're right," said Frank, as more noises arose all around them.

CHAPTER XVIII : WHEN FRANK STOOD GUARD
Pretty soon things began to look fairly cheerful in that lonely glade situated in the heart of the tropical forest. A fine fire crackled and shot up its red flames, lighting up the opening in which the young aviators had so luckily alighted.

Andy was bending over the fire making a pot of coffee, for they had brought along with them the necessary cooking utensils, including a frying pan, not knowing how long they might be adrift in the wilderness, far from the domicile of any human being.

"How do you find it?" he sang out, for his chum had been examining the aeroplane as well as possible under the circumstances.

"Everything seems to be hunky-dory," came the reply. "I'm going to start up the engine now to see if it works without a hitch."

"Don't I hope so," was what Andy said, as he paused in his task to watch.

A minute afterward he gave a little cheer, as the familiar throbbing sound was heard, making the sweetest music that ever greeted the listening ear of an aviator.

"That sounds good to me, Frank!" he cried.

"Nothing wrong about it, thank goodness!" came the reply of the other, as he again shut off power, because they could not afford to waste a drop of their valuable supply of gasoline.

"Well, suppose you drop in here and sample this brand of coffee. What with the cold snack we brought, and which still holds out, we ought to get along right decently, Frank."

"I tell you right now," replied the other, as he came up, "I'm hungry enough to eat anything going; yes, even some of our native cook's worst garlic-scented messes. And that coffee just seems to make me wild. Shove a cup over this way as quick as you know how, brother. Yum, yum, that goes straight to the spot. And this cheese and crackers isn't half way bad, even if it is pilot biscuit."

"Well," said Andy, "ain't you a pilot all right, and don't they feed sailors on this hard tack generally? Sure we've got no kick coming. Everything is to the mustard, and if you asked me my opinion right now I'd say things are coming our way."

"Listen to that chorus, would you?" remarked Frank, as various sounds arose all through the dense timber around them; "they seem to be heading this way sure enough."

At that Andy reached again for the gun on which he seemed to depend so much.

"Well, if any of 'em take a sneaking notion to look in on us, why I'm meaning to use up a few of these flat-nosed cartridges in this six-shot magazine," he remarked, sturdily, as he glanced cautiously around.

"No fear of that now," said his chum, reassuringly. "The danger will come, if it does at all, later on, when we have more trouble keeping the fire going. So after we get this supper down we shall have to gather fuel. It may not be quite so nice to go after it when we see a line of yellow eyes watching all around."

"Oh, shucks! You're just stringing me now, Frank. If I really thought they'd be as bold as that, why I'd climb a tree, that's what."

"What good would that do, tell me?" jeered the other. "Why, these cats just live in trees and can leap twenty feet if they can one. Perhaps if you found a hollow tree now you might feel safe, but in the branches of one—never! Why, the monkeys would come and laugh at you. The ground is the best place for us, after all, Andy."

"More coffee in the pot, if you ain't afraid of staying awake," suggested the cook.

"That would just suit me, for you see I'm more afraid of going to sleep than anything else while on guard duty," Frank remarked, soberly.

By degrees Andy realized that this business of camping in the heart of a tropical forest was no laughing matter. Still, they had escaped so many threatening perils that he was beginning to believe they must be under the protecting wing of God and that success lay just ahead.

They sat up and talked for a long time. Neither would admit being at all sleepy, and yet Frank caught his chum yawning ever so many times.

"Here, you, just make up your mind to turn in and get seven winks," he said, pretending to be giving orders with all the airs of a commanding officer.

"I suppose I'll just have to," came the reply, as the other started to roll up close to the fire, for they had no blankets with them this time. "Do you know I was just thinking about Perc."

"Well, what of him?" asked Frank.

"What if they start to chase us again in the morning? Are we going to put up with that funny business right along? I say no. Let's warn 'em that we're armed and can bore a hole right through their jolly old biplane, upsetting them any time they get close enough. I'm drawing the line on tomorrow, because somehow I feel it in here that it's going to be the greatest day of my life," and Andy laid his hand on his heart as he spoke.

"Yes, that would be our best plan," admitted Frank. "We've already stood quite enough of that funny business, as you call it. They even fired at us. Depend on it, Andy, they won't follow us very far next time."

And Andy, seeing the way his chum's mouth was firmly set, made up his mind that Frank had reached the end of his patience. Contented with the prospects for the morrow he therefore lay down to get some sleep.

"I say, Frank," he called out presently.

"Well, what now?" asked the one on guard, who had possession of the rifle and had taken up his position so that he could have a clear view of the open space all about the camp.

"If one of the prowlers tries to drag me off, remember I've got my leg tied to this stake I knocked into the ground. While he's tugging you can have a bully good chance to knock him over, see?"

"All right," grinned Frank. "I'll remember. But let out a whoop if you feel yourself going. I might be looking the other way."

"You just bet I will," mumbled Andy, curling himself up as near the fire as he dared creep.

And in three minutes Frank knew from the heavy breathing coming from that quarter, that his chum had found no trouble in getting to sleep, regardless of the various sounds welling up from the neighboring forest, and the fears that possessed his boyish soul.

Frank sometimes sat down; and again, feeling cramped in this position, he would rise to his feet, and walk back and forth. But all the time he kept the gun in his possession, with the hammer pulled back, ready for business. And constantly did he maintain a close watch along the nearer border of the undergrowth that lay there, so dense and filled with mystery.

Time passed on.

It seemed as though a thousand things flitted through the active mind of the young aviator as he thus stood guard over the camp. Once again he was back in good old Bloomsbury, where he had spent so many happy days. He could see the faces of his boyhood friends, Larry, Elephant and others.

Frequently he would detect a movement here or there among the trees; and at such times he could easily imagine that some animal belonging to the forest was creeping closer in. The question was, whether simple curiosity urged them to do this thing, or a design upon the occupants of the camp.

Frank had been in other situations calling for considerable pluck, and never failed to meet the emergency, nor did he now.

It must have been some three hours back that Andy lay down to sleep. That had been the limit of time arranged upon; but Frank did not show any signs of intending to awaken the other.

"Let him sleep," he said to himself, as he walked up and down, for by now he was beginning to feel very drowsy himself, in spite of the coffee. "He needs it more than I do. And besides, I'm a little dubious as to what sort of watch Andy would keep. Anyhow, I can stand it a while longer. Hello! what's that mean?"

His attention had been attracted toward a movement in the brush at the nearest point of the forest. It was not thirty feet distant. Could one of those long-bodied muscular jaguars cover that distance in a wild leap? What if without warning he should see a tawny figure flashing through the air, and headed straight for him?

Frank threw the gun up to his shoulder as if to try and see how readily he could cover such a flying form. As he did so he heard a low and ominous growl, which undoubtedly sprang from the very spot where he had just caught that suspicious movement.

He bent his head to look closer, and as he did so an exclamation fell from his lips.

"And that's no owl staring at me, either," he said to himself, as he caught the singular glow of what seemed like two balls of fire, just under the lower growth.

Frank knew what they undoubtedly must be. He had seen the orbs of a cat shine in this phosphorescent way in the darkness. There could be no doubt but that he was being surveyed by one of those savage beasts whose whining he and Andy had heard around the camp for hours.

"And I declare if that purring sound doesn't come from there, too," he muttered, as he sank down upon one knee, the better to aim his rifle. "What was that the old señor was telling me about these beasts? Didn't he say they jerked their tail to and fro like a pendulum, and made a queer noise just before they jumped? If that is so then this fellow is getting ready to leap over right now. Time I was doing something, if I don't want him to drop on my chum like a rubber ball. Well, here goes to take him between those yellow eyes. Steady now, my boy, steady!"

CHAPTER XIX : FIREBRANDS AND JAGUARS
"Bang!"

"Wow! are they coming in on us?" shouted Andy, suddenly aroused by the sharp report of the repeating rifle.

He bounded to his feet, and from his manner of action it was plain to be seen that he remembered exactly the condition of affairs at the time of his taking passage for the Land of Dreams.

Frank had aimed straight between those glowing eyes at the time he fired. And as he was perfectly calm at the time, it stood to reason that his bullet went direct to the mark he meant it should.

He saw a yellow object threshing about under the dense growth, and realized that he had given the adventurous jaguar something that was apt to wind up his career as a terror to the monkey hosts of the forest.

But this was not all Frank saw. Another figure had appeared just ten paces farther along, and he realized that a second jaguar had crept out of the copse, evidently bent on charging the camp.

"There's two more, Frank! Oh! my, it's a dozen I guess!" whooped Andy, who had found a better opportunity to see in other quarters.

"Grab a firebrand, quick!" shouted Frank, trying to get a bead on the second slinking figure; and yet hesitating about firing, because of the great risk that must ensue should he only wound the fierce monster.

He saw out of the corner of his eye that Andy made a plunge toward the fire and was snatching a brand out in each hand.

"Wave them around your head, and shout like thunder!" he cried, at the same time starting in to do this latter himself.

Perhaps it was a comical thing in some respects. Andy often laughed over it afterwards; but just then it seemed serious enough. The way both of them let loose with their strong young voices would have made a football cheer captain turn green with envy. They fairly awoke the echoes slumbering in the depths of the forest.

And Andy waved those two torches like a good fellow, back and forth, in and out, weaving them as an expert Indian club athlete might do with his heavy weights, until the rushing flames roared again and again because of their rapid passage through the air.

"They're licked already, Frank!" whooped Andy, as he daringly began to advance with his flaming beacons swinging around and around. "Look at the coward moving back, would you? Talk to me about your guns, they ain't in it with these things, when it comes to scaring off a pack of wild beasts. Scat! you terror, or I'll just swat you one alongside your jaw. Growl at me, will you? There, take that, hang you!"

To the astonishment of Frank, Andy, who had rushed straight at one of the retreating animals, suddenly hurled a blazing brand straight at the jaguar. In his palmy baseball days Andy had never amounted to a great deal as a pitcher; but all the same he made a beautiful throw right then and there.

The whirling, blazing fagot of wood struck the slinking beast full in the side. Frank threw up his gun, ready to shoot should the jaguar, as he feared might be the case, leap at his chum. But there proved to be no need. Instead, the brute was evidently alarmed at this novel weapon, something entirely beyond his ken.

Frank heard him give a snarl that told of mingled rage and fright. Then he made a spring, but away from the fire, and into the dense undergrowth from whence he had just issued so bravely.

Looking around Frank saw that the glade was deserted of four-footed foes. The whirling torches had done the work.

"Bully for us!" shouted the excited Andy, ready to dance in his delight over the success of his labors. "Didn't we send 'em a flying, though? Perhaps they just dare to come snoopin' around here again, when they're not asked! Frank, I guess you nailed that critter, all right. Dast we look and see?"

"Sure we will," returned Frank, instantly. "Pick up another bit of burning wood. Then let me go just ahead of you, so that I can shoot if I have to."

They thus boldly advanced toward the spot where Frank had first sighted the blazing yellow orbs.

"I can see something there!" declared Andy, who possessed sharp eyes.

"Yes, it's the beast, all right. But I can't say for sure whether he's down on his back, or crouching for a spring. Careful, not so fast, Andy." And Frank kept covering the object with his rifle as foot by foot they kept on.

"He's lying on his side! He's a dead duck, all right!" sang out Andy, waving his fire vigorously to and fro.

"You're right, he's stone dead!" observed the other, a touch of natural pride in his voice; for it was no mean feat to kill so ferocious a beast as a jaguar, after seeing only his two eyes shining in the darkness beyond the fire-light.

Frank stooped down, and catching hold of one of the dead animal's hind legs, started dragging it toward the fire.

"Hold on there," said Andy; "don't tell me we're going to have a steak off that old cat? I can stand for a good deal, but I'd go hungry a long time before I'd eat any of him!"

"Don't worry about that," laughed Frank. "But think what a bully old rug his hide will make some day. I'm going to try and take it off, if I can, while you're getting breakfast in the morning. It's worth while."

Andy looked as though he doubted the ability of his chum to accomplish the feat; but then he was counting without his host; for when the chance came Frank deftly removed the pelt, and kept it for a reminder of his hazardous shot.

Andy insisted on taking his turn at playing guard, when he found out what time it was. First of all Frank saw that the fire was revived, with plenty of fuel handy. Then, after giving his chum a few last instructions, he consented to lie down. But his sleep could not have been very sound, for frequently he would raise his head, and take a look around; seeing nothing suspicious he would again lie down.

So the night passed away.

Frank was on deck an hour and more before the dawn came. He felt too anxious concerning the possibilities of the coming day to sleep much.

So Andy started to get breakfast, such as it was, before the night had really gone. He excused himself by saying that while he was not at all hungry, the operation had to be gone through with, and the sooner he was at it the quicker they might be free to mount upward.

Frank knew what a terrific load was on his chum's mind, and how he thrilled with suspense, now that they were so near the realization of his highest hopes or worst fears.

And so he too set to work to remove the jaguar skin, for it would make a pretty decent rug, if it could be properly preserved.

Morning was just breaking as they sat down to partake of the simple meal. Neither of them seemed to care for much. It was indeed no time for feasting, or making merry, when the day had probably dawned that was to settle their mission, one way or the other.

"One thing good," remarked Andy, hopefully, "there doesn't seem to be any strong wind blowing this morning."

Frank had been studying the lay of the land in the glade.

"I tell you we're going to have all we can do to squeeze up out of here without scraping against any tree before we can rise above them," he observed, presently.

"But don't you think we can do it?" demanded his chum, anxiously watching his expressive face.

"I think it is possible," came the slow reply; which after all gave Andy new cause for distrust; since his cousin was so cautious a fellow that he seldom if ever gushed over anything; at the same time he never expressed doubts when he felt positive.

"But!" cried Andy, "there's no other way to fly; we couldn't take the aeroplane to another place; and I reckon there isn't a cleared field within ten miles of here."

"No, it must be done right where we are. Now, I'm going to measure the opening to find out its widest dimensions. Then we will take the monoplane as far back as we can, and make all arrangements for a rapid start. But to rise above those trees, even the shortest of them, is going to call for considerable management, and some great good luck in the bargain."

"But, Frank, you've done it before," declared Andy. "You know you made lots of short starts that beat all the records. That's your best hold. And, Frank, we've just got to get out of here. Everything depends on it."

"Sure," responded Frank, cheerily enough; "and we'll manage somehow, never fear. Now to foot off the space. Count to yourself, and we'll compare notes when I get to the other side. This looks the widest range, according to my eye."

So they both started off, Frank placing one foot close in front of the other, and Andy keeping alongside in order to do his own counting. In this way they passed from one side of the glade to the other; and Frank was secretly pleased to find that the distance was considerably more than he had judged possible.

Besides, the trees happened to be much lower on this side, which fact would be of considerable benefit to them when they started to make the run, and rise.

Frank was still muttering the number of feet to himself, and had arrived within something like five yards of the nearest trees, when, without the slightest warning, he heard Andy let out a screech that could have but one meaning.

He had surely sighted something that spelled peril to one or both of the Bird boys. Frank had wisely kept the rifle in his hand, and instinct caused him to throw this up to his shoulder, though as yet he had not the slightest suspicion as to what the nature of the danger might be, nor the quarter in which it lay.

CHAPTER XX : THE AEROPLANE BOYS ONCE MORE AFLOAT
"Frank! Oh! Frank!"

More than a few times had it fallen to Frank Bird to drag his cousin and chum, Andy, back from some impending danger. Now the shoe seemed to be on the other foot.

Even as he looked hastily up, startled by these sudden cries, Frank felt his arm seized in a frenzied clutch, and himself jerked backward.

"What is it, Andy? Here, hold on, let my arm free, and tell me!" he exclaimed.

"Look there; and you were going to walk right up against it! Oh! Frank, what a horrible monster!" Andy replied, in trembling tones, as he strove to point toward something that he had seen just in the nick of time.

"Whew! I should say you were right! Ain't he a dandy, though? And if I saw him at all, I thought it was a great big vine hanging from that tree! Ugh! look at him stretch his mouth, would you? Andy, thanks to your sharp eyes I'm here, instead of in his slimy folds. I guess he could crush an ox. They say nothing can stand the pressure, once they get a couple of folds around."

"Is it a python?" gasped Andy, his horrified eyes glued on the spectacle of the slightly swaying ten feet of snake that hung from the limb of a great tree, in part as thick as Frank's thigh.

"About the same thing," replied Frank. "Down here they call them anacondas, and in other parts of the world they're boa-constrictors. I guess the whole bunch belongs to the same family of squeezers. But that fellow is in our way."

"Well, yes, if you're still determined to run the aeroplane across lots toward this side of the opening," Andy remarked with a shudder. "Why, perhaps that old chap might get gay, and grab hold, just when we expected to go sailing off. That would be a calamity, not only for him, but the Bird boys in the bargain."

"All right. Then he's got to get his," Frank observed.

"What are you going to do?" demanded the other, nervously.

"Take a crack at his head," came the reply. "Once let a flat-nosed bullet from this little Marlin hard shooter smack him on the coco, and there'll be a funeral in the anaconda family."

"But for goodness' sake make sure work of it, Frank. What if you just wounded the monster? He'd come whirling along at us like a hurricane. And I'm sure he must be thirty feet long, if he's a dozen. Look at the thickness of his neck, would you? Be mighty careful, for his head's swinging a bit, you notice. That was what made me get sight of him. Say, Frank!"

"Well, hurry up. He may take a notion to move off, and I'd lose my chance, Andy."

"How'd it do for me to get some fire, and shoo him away?" suggested his cousin.

"Don't know how it would work," replied Frank, smiling a little, however, at the faith Andy seemed to have in a blazing brand, now that he could look back to his late experience with the jaguar. "Never heard that snakes were afraid of fire. And besides, there's no need. Now keep quiet, and watch. You'll see something worth while; but be ready to jump clear."

He had already dropped down on one knee. The Marlin stock rested against his cheek, and his eyes sighted along the barrel. Andy fairly held his breath, his startled eyes glued on that swaying head of the monster.

Then came the sharp report as Frank pulled the trigger. He instantly jumped back, and by a rapid motion of his hand sent another cartridge into the chamber, the clever mechanism of the gun proving that it was built so as never to fail in an emergency.

Andy had accompanied his chum in that backward movement; but never for an instant did he remove his eyes from the strange spectacle that was taking place there in front of them both.

Undoubtedly the well aimed bullet had crashed through the fearful head of the suspended anaconda. Instantly it released its many coils above, and a tremendous length of writhing snake could be seen whipping over the ground. Nothing in the way of small vegetation could stand in the path of those powerful springy coils, as they shot this way and that.

"Oh! my!" gasped the astounded Andy, as he moved farther back, so as to avoid any chance contact with the flying destructive force that was leveling everything in the glade for twenty feet around. "Did you ever see anything to equal that? Talk to me about your harvesting machines, here's one that's got 'em all beat to a frazzle. Ain't he ever going to give up the ghost, Frank? Guess these anacondas must have the nine lives of a cat!"

"Well," remarked Frank, "you must have forgotten that among boys it's said that a snake won't die till sundown. I've seen one's tail wiggle hours after we thought the thing was stone dead. There, he's moving off into the forest, and a good riddance. While I'd like to measure the serpent just from curiosity, we've got no time to waste waiting for him to kick the bucket."

"That's right," assented Andy. "And as for going anywhere near such a whirlwind, you'd have to excuse me."

They watched the dying anaconda gradually vanish in the depth of the forest; and both boys were glad that it had turned out that way, since they were anxious to depart from the place.

"Don't I wish I'd had my little camera along, so I could have snapped a shot at that dandy chap! The fellows would believe me then, when I told about what happened to us here. And anyway, Frank, I don't think we'll forget this camp, do you?"

"Well, hardly," replied his chum, smiling broadly. "Because we've sure had enough happen to us here to make us remember. But I'm glad to find there's going to be more space for the run than I thought at first."

"We'll need every inch of it," declared Andy, as he looked dubiously at the tops of the lower trees about the place where the snake had held forth. "Don't I wish we'd brought a few sticks of dynamite along, though."

"For goodness' sake, what would we want with dynamite? Think you could have blown up that snake, do you?" asked Frank, as they started to cross the glade toward the waiting monoplane.

"Oh! shucks, no. I was thinking how we could plant 'em under a bunch of those trees and enlarge the gap!" declared Andy.

At that Frank burst out into a hearty laugh.

"What a fellow you are for wild notions. Think of us blowing up the forest to make an aviation field! I reckon, however, seeing that you haven't got the dynamite, Andy, we'll have to do the best we can. Take hold here and we'll push the machine just as far back as it will go. Perhaps we can gain a few yards at this end that will count in the long run."

Frank was particularly careful about every little detail. He knew just what he had to depend on. In the past he had made it a pet hobby to rise in as short a space as possible; and now this faculty seemed destined to prove a valuable asset in their speedy climbing up.

"All ready?" he asked, grimly.

Andy took one last look at the face of his chum. He saw that Frank's mouth was compressed in that firm way that stood for so much; and somehow Andy's wavering confidence returned in full measure. When Frank Bird looked like that, things always had gone according to his will; and they must now!

"Yes, I'm fit, Frank," he said, quietly. "Let her go when you're ready!"

In the many times that the two boys had made ascents, Andy could never remember that his pulses throbbed with one-half the suspense they did now. Not even on that never to be forgotten initial performance, when for the first time they felt the strange sensation of leaving the solid ground in a flying machine, had he been so excited, so nervous, so filled with alternate hope and fear.

Frank had taken every possible precaution. He had thoroughly studied the ground, and made sure that no obstacle would be apt to cause the running gear of the aeroplane to swerve, and thus throw them off their course.

All he could do was to start the machinery, get a rise at the quickest possible second, and be ready to shut off power if he realized that the feat they were about to attempt were impossible, so as to avoid smashing the planes against a tree.

"Then here goes!" he said, calmly.

Andy held his breath as he heard the engine start off at a tremendous speed. He felt as though a giant hand had plucked them from the spot where the aeroplane had been planted for the start. Across the glade they went speeding. His heart almost jumped into his mouth he believed, as he felt the little craft start to leave the ground, as Frank manipulated the planes, and elevated them so as to catch the air under the broad blades.

They were rising rapidly now! Would they manage to clear those terrible treetops that stood like a grim barrier in their path?

Higher yet did Frank throw the planes, so that they actually seemed to be climbing straight upward, according to the vivid imagination of Andy; who, clutching the upright at his side, waited for what was going to happen.

It was too late now to retreat! They had gone too far to stop, and try again! No matter whether for good or ill, their kite had been tossed to the winds of heaven, and they must abide by the consequences.

Andy gave one little squeal, for it could not be termed anything else under the sun. This was when they shot past the most prominent branch of the tree that happened to stand directly in the way of the rising aeroplane. Andy believed that the wheels below must have actually brushed through the foliage, for he always declared that he heard a fierce "swish" as they passed.

Had they caught even one little bit, something dreadful might have happened, and the precious aeroplane, on which everything depended, meet its sad fate; not to speak of the nasty fall the Bird boys would have suffered.

But Fortune was once more kind to the young adventurers. They passed safely through the peril, and were speedily fully launched upon the wide open expanse of space!

"Hurrah!" shouted the exultant Andy; but it might be noticed that his voice was a bit husky, even as his face seemed chalky white.

"A close shave," remarked Frank; who himself had been rigid while they were thus taking such desperate chances; "but we made it, thank goodness! I hope that will be a lucky token of what the day has in store for us."

"Amen!" echoed his chum; and there was no levity in his tones, either.

The sun was just rising. Below them lay the dense foliage of the almost impenetrable forests, from which they had just made this almost miraculous escape. And both young aviators, as if by common consent, started to sweep the horizon around with their eyes.

"See anything of it?" asked Andy, eagerly.

"I thought I did away over yonder toward the mountains; but I guess it must be a big bird hovering high up, a condor perhaps," Frank replied.

"Well, there isn't any sign of the biplane, that's sure," Andy went on in a relieved voice. "Perhaps they didn't have as good luck in landing as we did, and had a nasty spill. Don't I hope they busted some of the planes, or part of the little old Gnome engine, so we won't have to be bothered with 'em again?"

Frank made no remark. While as a rule he refused to let anything like bitterness dwell in his heart, still, this was a case where everything was at stake; and if the bothersome revolutionists kept chasing them in the biplane they were apt to give a great deal of trouble. And secretly he could echo Andy's wish that the biplane might be temporarily crippled, so as to be unfit for flying.

"Now, what's the programme?" asked Andy, when they had covered several miles.

"We've just got to head for the mountains yonder," replied his chum. "You know, he declared it was a valley that lay among the mountains; and it must be, to be surrounded by high cliffs. Once we get among the hills, we'll sail back and forth, combing the whole region, and hoping sooner or later to discover his queer prison."

Andy lapsed into a state of silence; but he kept watching ahead as they drew gradually nearer the uplifts. Doubtless but one thought held dominion in his mind, and this was that somewhere amidst those same mountains the father whom he loved so dearly was waiting, and hoping for an answer to his appeals for aid.

CHAPTER XXI : THE LAST LITTLE HOT AIR BALLOON
"Did you ever see a wilder region?" asked Frank, about the middle of the morning, when they had alighted on a broad, level plateau, so as to allow him to look over some little matters connected with the engine, that he believed needed attention.

Andy had been using the binoculars pretty much all the time they were aloft, but without any success. Many times be began to think he had sighted something that looked like cliffs rising up, and a wild hope had seized upon his devoted heart; but upon Frank bringing the airship in that quarter, in answer to his frantic appeals, it had proven to be a false clue.

Cliffs they saw in plenty, but as yet none enclosing a valley so as to imprison an unfortunate aeronaut, whose runaway balloon had dropped with him into its depths.

Still, the day was not nearly half over. And the monoplane behaved splendidly; so that they could hope to continue the search as long as their supply of gasolene held out.

"I'll never give up hunting," Andy declared, as he stood there, watching his chum potter with the engine and examine things in general. "No, not as long as this fine little machine stands by us. We can get more gasoline if necessary, for we brought a good supply aboard the boat. When we've gone as far as we dare down this way we'll make another start further on."

"I'm with you, Chum Andy, and you don't need to be told that," observed Frank, quietly, while he worked on.

"As if I didn't know that and counted on you through thick and thin," declared the other, with a look of sincere affection.

"Well, now we're ready to go up again," remarked Frank; "and there's no use asking if you feel like it. So pile in and we'll make a flying start from the top of this rocky plateau."

"What a difference from our last start," observed Andy, with satisfaction, for they were on an elevation with a valley far below, and the air was decidedly bracing for the tropics.

"I should say it was," laughed Frank. "Do you know what it puts me in mind of?"

"I bet you're just thinking of when we won that race to the summit of Old Thunder Top, where nobody had ever been able to climb before, and how we had to make our start for home from that little plateau, plunging off into space."

"Just what I was," declared Frank. "But here we have a longer swing and it's going to be a snap of a launch compared with some we remember."

"Ugh!" grunted Andy, "will I ever forget the one this morning. But let loose, my boy. I had just sighted a likely looking place away over yonder, at the time you said we ought to take advantage of this fine landing stage, to look things over. Just head her that way when we get going, will you?"

"Sure; anything to oblige," assented the other.

The launch was just as easy as they had anticipated. Indeed, Frank seemed to have gotten this part of the programme down to a fine point and could accomplish it apparently as well as a Wright or a Curtiss.

Ten minutes later and the monoplane was soaring toward the region which Andy had denominated as a "likely spot."

"Look at that big bird watching us from that pinnacle yonder!" exclaimed Andy, as he lowered the glasses for a moment.

"I see him," replied his comrade. "And there's no doubt now but what that is a condor of the Andes. He thinks we must be some sort of bird, which we are, of course, and is wondering whether he ought to flap his wings and go up higher or hide behind that church steeple of rock."

"I only hope he don't take a measly notion to fight us, that's all," remarked the other, as he glanced anxiously toward where the Marlin was secured to the framework of the airship.

"No danger of that," Frank continued. "A condor is like our vulture or buzzard, a scavenger; and he lacks the bravery of the bald-headed eagle that attacked us when we came near his nest on the tip of Old Thunder Top. Look there, he's off, Andy, and at a good lively clip, too. Good-bye, old chap, and good luck!"

Andy had lost all interest in the great bird of the western Andes. He was focusing his attention upon the place that he had marked as a likely spot.

"Frank," he said, presently, in a husky voice, "could you drop a little lower and slow down some?"

"That's easy," replied his chum, readily enough. "What has struck you now, Andy?"

"It looks more and more promising to me," came the slow reply, as Andy kept the glasses up to his eyes.

"Then you can glimpse something like cliffs?" asked Frank.

"Yes, and there's no doubt about that part. I'm waiting now to see if the wide valley is wholly enclosed!"

"And if it is, you think—"

"It must be the place! Oh, Frank! What if we are near the spot? Would he still be alive, or has he given up the fight? That condor perched up on the pinnacle—was he only waiting for the time to come when he could fly down? Perhaps—oh! what is that moving yonder? Look, Frank, Frank, something is coming up above the top of the mountain! Can you see it? If you could only take the glasses and tell me, for my hands are shaking so I can't hold them!"

"Brace up, Andy. I can see what you mean without the glasses. There, now it has risen above the line of rocks—something that bobs to and fro like no bird ever flew—something that floats, now this way and now that, just as the wind blows. Andy, upon my word I believe it is, it must be—"

"Oh, say it for me, please, because I just can't find words!" cried the other.

It was a wonder that in their tremendous excitement something disastrous did not happen to the aeroplane, but Frank had wisely cut off some of the power, so that they were just making fair headway at the time.

"It is a little parachute balloon, just like the one that carried that message into the cocoa grove of Carlos Mendoza!" ejaculated Frank.

"Then it means that we have found the valley prison!" gasped Andy.

"Sure, that's a fact. The cliffs yonder are on one side of it!" Frank cried.

"And Frank, don't you see, the fact that another of those little messengers of hope has just come up out of the valley shows that he is alive!"

"You just bet he is, Andy; and we're going to be with him in three shakes of a lamb's tail!" declared the other.

Andy could not utter another word; he was too full of emotion. So he just sat there and stared and waited, his heart doubtless thumping against his ribs as it had never done before.

Of course, when Frank gave utterance to that boast he did not really mean it, and only had the encouragement of his chum in view. He knew that it was apt to prove a difficult task, landing in that enclosed valley, where the vegetation must be of a tropical order.

First of all they must circle around over the wide expanse to take in its features and discover the prisoner. Then Frank could lay his plans accordingly.

Gradually they began to see more and more of those marvelous cliffs. They seemed to stretch in an unbroken cordon completely around the valley. If they were as near like adamant as they looked it would take a man years to cut steps to the lofty top, even though he were given proper tools for the work.

And presently they cleared the near side, so that the monoplane floated directly above the valley itself.

"Careful now, Andy!" warned the cautious Frank. "Hold yourself tight while we circle around, dropping lower all the time. Suppose you shout, though I should think he'd have heard the noise of our exhaust before now!"

He had hardly uttered these last words when there came a cry from below.

"Look, look, Frank, there he is! Oh, what a blessed sight that is! My father, and alive after all! See how he runs and waves his hands! What will he say when he knows that it's his boy in this airship come to save him?"

"Call out and tell him!" said Frank, hardly able to control his own feelings, though he knew he must or they might meet with an accident in this supreme moment of victory.

So Andy did shout, calling upon his father wildly and waving his cap to him. The prisoner of the enclosed valley seemed dazed at first. Perhaps he had been deceived so many times by his dreams of being saved that he feared this might prove only another delusion. They could see him stand there and put his hand to his head as he stared. It was so very wonderful, this coming of a modern aeroplane to snatch him from his living grave. And then that voice, how like the one he had never expected to hear again!

But by degrees, as the little Bleriot monoplane sank lower, and the forms could be more plainly seen, he began to grasp the truth. Again he showed the most intense excitement, waving his arms and running to keep up with them.

"Wait," said Frank, presently, as he saw that Andy was so excited he could not carry on an intelligent conversation. "I'm going to speak with him and find out if there's any clear spot where we can land."

"Uncle Philip!" he shouted presently, when Andy had subsided. "This is Frank, your nephew, and Andy, your own son. Is there any clear place where we can land?"

The aeronaut understood, because all this was right in line with the profession which he had been following at the time of his vanishing from mortal sight.

He indicated the quarter where a landing might be risked and upon investigating by hovering over the same, Frank decided that it promised success.

So the aeroplane dropped down and touched ground. It bumped along for a little distance and then Andy, leaping out, managed to bring its progress to a halt. They were in the enchanted valley, from whence those wonderful messages had floated, one of which, by a strange freak of fate, had eventually reached the boy thousands of miles away, for whose eyes it had been intended!

And immediately Andy was clasped in the arms of his father. He knew him despite the long gray beard, which had grown during his many months of confinement, with hope daily choked by despair. His clothing was almost in tatters, and he seemed thin and peaked; but the look upon his drawn face now was of supreme happiness.

Then, after they had in some measure recovered from all this intense excitement, the boys sat down to tell what a miracle had been wrought, bringing the message to the home in far away Bloomsbury. With an arm still encircling the form of his boy Professor Bird listened and asked many eager questions.

"And to think," he said, finally, "that little messenger you saw going up just now was constructed of the very last fragment of the old balloon silk. I made a fire with flint and steel, filled it with hot air and sent it up with prayers, believing that it was my forlorn chance. And then I heard the exhaust of your motor. I feared my mind was giving way under the terrible strain. When I looked up and saw an aeroplane sail into view I fell down on my face, believing I had gone mad. But it was a blessed reality, thank God!"

Plans were soon under discussion looking to leaving the valley as soon as possible. About this time Andy happened to think of something and began to fumble at his pocket.

"Oh, how I hoped and prayed when I bought that, father, that I might have the happiness of seeing you smoke some of it," he said, as he drew out a little packet of tobacco, on which the late prisoner pounced with all the delight of an inveterate user of the weed, who had long been deprived of a pleasure.

"I have been using dried leaves of a wild grape and some other things," he admitted; "but after all they were only vile substitutes. It was thoughtful of you, my boy, to remember my weakness."

And Andy snuggled up close to him as he commenced to puff at his pipe, using a match for the first time in many moons and smiling whimsically when he struck the same, as memory played queer pranks within.

Meanwhile Frank wandered around to survey the scene of the professor's imprisonment and figure how they were ever going to get out with the aeroplane.

CHAPTER XXII : RESCUED
"What's the hurry?" asked Andy, when once they began to talk over their plans for leaving the valley.

For once Frank agreed with his chum. They had plenty to eat along with them and it might be just as well to wait for another day. By that time all of them would have recovered to a great extent from the excitement that had told upon them, particularly the professor, none too strong.

So it was finally concluded to stay right where they were until another morning, when one at a time Frank would endeavor to convey them out of the valley, not daring to risk two passengers at once with such a poor field for the start.

The time passed quickly enough, for there were a thousand things to tell on both sides. The aeronaut described his accident and related how he had lived through all the dreary months that had gone. Fortunately there did not happen to be any fierce wild beasts in the cliff bordered valley, and while he had had adventures with venomous serpents, fortune had stood by him.

He showed numerous little contrivances by means of which he had secured game enough to supply his needs. There were nuts in abundance and some wild fruits which, as a scholar, he knew the value of.

Water could be had in plenty, as a lovely stream flowed through the valley, diving down at one end and vanishing in the rocks, to find an outlet such as the human prisoner prayed for daily in vain.

Why, it was evening almost before Andy realized it, so quickly had the hours sped along. How proudly had his father asked all about the monoplane, which he examined with the most intense interest, knowing it to have been mostly made by the two enterprising Bird boys.

From the way in which he smiled and nodded his head after this survey it was evident that he was very well pleased with what they had done. And he also made them tell all about that famous race through the air to the hitherto unsealed crown of Old Thunder Top, which he remembered very well.

"And now, let's think of having a jolly little meal," said Frank, as the shadows began to lengthen down below the lofty cliffs, which was a pretty good indication that night could not be far away.

"Count me in," said Andy, jumping up, for it was his duty to get busy when the time came to make a fire and prepare a repast. "I guess we've got coffee for a few times yet, and I smuggled a can of Boston baked beans along when Frank wasn't looking, knowing that father used to be right fond of 'em."

"Coffee! Beans! Why, you fairly take my breath away!" exclaimed the one who for so many months had been deprived of all the comforts of civilization and forced to sustain his life in the most primitive manner.

When supper was cooking the professor made some excuse to wander off. Frank knew, though, what ailed him.

"It's the aroma of that blessed coffee, that's what," he said to Andy, who had looked a little troubled at this action on the part of his father. "It's been so long since he's smelled it that it just makes him wild. I know, because I had a little experience that way myself once, only it was two weeks I had to go without when we were camping and not many months. When supper's ready he'll come with a rush, mark me, Andy."

And he proved to be a true prophet, for no sooner had Andy lifted up his voice to call that the meal was ready than the professor broke through the bushes and hastened to take his place.

Frank lost not a second in filling a tin cup of the amber liquid and handing it to the late prisoner of the valley.

He tasted and then nodded his head.

"Sweet nectar, my boys!" he declared. "One never knows how little things like this go to make up a portion of one's life until a cruel fate has deprived him of them all. And to think I have a boy so thoughtful as to fetch along a packet of smoking tobacco and a can of the real Boston baked beans. Thank you, Frank, that's a heaping pannikin you've given me, but I suspect I'm equal to the job."

They made a happy trio as they ate and chatted and laughed. Perhaps that was the first hearty laugh Professor Bird had given utterance to since the day he started in his ill-fated balloon from Colon on the Caribbean coast to cross the Isthmus of Panama.

Before they went to sleep that night all preparations had been concluded looking to getting out of the trap in the morning. Frank had made his estimations and knew to a nicety just what his engine could do. Once free from the valley he believed they could head direct for the distant Magdalena, carrying two passengers and making short flights. It was true that as yet he had never taken up any second passenger and it entailed an additional tax upon the motor, but he had great faith in the little Kinkaid engine and felt that it would respond nobly to any additional demand made upon it.

But it would be advisable that he carry the professor out of the valley and land him on that plateau where they had made their last halt, ere going back for Andy. Then, from that elevated place they could start on the return trip, with everything favorable for a successful flight.

The night passed at length, though it must have seemed interminable to Andy. Frank knew that often his chum would rise up on his elbow and put out a hand gently, just to touch the form of his sleeping father close to him. And Frank did not wonder at it, for there were times when even he found it difficult to realize that their remarkable mission had actually proven successful.

At length the day came.

They were early astir, for much remained to be done. And there would needs be deft manipulation of the gallant little monoplane by its clever pilot, if two separate flights out of the enclosed valley were to be undertaken.

Finally all was ready.

The professor had really next to nothing he wished to bring away. The valley had grown hateful to him because of his enforced stay and he never wanted to see it again.

He took his place in the seat usually occupied by Andy. His face was grave, for he knew what risks they were running. But surely the lad who had piloted the frail craft through so many perils would not fail now!

"Good-bye, both of you!" said Andy, beaming upon them, as he prepared to assist in the launching. "Please don't forget me down here and let me root, hog, or die for months. Birds of a feather flock together, you know, so come back again, Frank."

Then came the start. It was anything but an easy job to get going in the small space allowed by the character of the valley, but Frank had figured it all out, measured the ground, removed such obstructions as promised to give trouble and had perfect confidence in his ability to make it.

And he did.

After that other ascent in the heart of the tropical forest he declared he did not mean to let anything appal him henceforth.

Once they started circling the valley, low down and just missing the tops of the trees growing there, Andy, sent vigorous whoops after them, and his father answered by waving his hand, for hat he had none.

So, guided by the master hand of Frank Bird, the aeroplane rose above the line of those hateful and cruel cliffs and for the first time since his captivity the man of science saw the blessed outside world again.

There was no trouble landing him on the accommodating plateau, after which the aeroplane started back for its second passenger.

Frank abated his vigilance not a particle. He knew that constant watchfulness must be the price of safety when one is venturing to imitate the birds and soar through the upper currents of the air.

Down into the valley he dropped, the monoplane behaving beautifully. And presently he was shaking the hand of his chum again.

Once more was a start made. Frank breathed easier after it had proven a success, for there were narrow escapes from a collision with some obstacle, and he knew only too well what that stood for.

"Now we're all right, I guess!" sang out Andy, as they came out of the depths and Frank turned the airship in the direction of the distant plateau.

Naturally Andy was as happy as a lark, singing and calling as they glided along, and finding scores of causes for attracting the attention of his chum. Finally Frank had to caution him to slow down and not try to make him look so much.

The trip was made in perfect safety. Indeed, Andy was now so confident of the capacity of the monoplane, as well as the skill of its pilot, that he expressed himself as ready to go anywhere in such a craft with such a driver.

It required some planning to arrange matters so that both Andy and his father could be carried at the same time; but Frank had been figuring on this and fixed it in his mind.

Even after the start he felt more apprehensive than he allowed the others to see, for this was after all an experiment. Aviators have gone up with two passengers and in monoplanes, too, but the limit of their stay aloft had never exceeded two hours, for the strain is very great.

So Frank hoped to find places where they might drop down to rest, thus making the journey in easy stages.

He believed they had plenty of gasoline to see them through, for an additional supply had been carried when starting from the neighborhood of the boat.

But once they were afloat he realized that he had been borrowing needless trouble, for the gallant little aircraft just acted beautifully and seemed to be able to speed merrily along with two passengers almost as well as with but one.

Of course there were many chances for trouble. There always are when traveling in an aeroplane, since the least thing that goes wrong means a descent or a fall.

Frank tried no lofty flight. He kept close above the tree tops, content to make steady progress in the direction where his little compass told him they would find the river.

Once away from the mountainous country and they were able to descend to still lower levels, where the chilly air changed to hot, and there were signs of life among the trees below—birds, monkeys and other natives of the wilds showing themselves at times.

It must have been a glorious sensation to the old aeronaut to be thus speeding along in a modern, up-to-date airship, after his enforced idleness for so long. Again and again did he express himself in that way, as he gazed over the expanse of country, and then allowed his eyes to rest fondly on the form of his boy, more dear to his heart than ever after what had happened.

"I think I see an open place beyond," remarked Frank, after they had been moving something like two hours after leaving the high plateau. "And it might be wise while we have the chance to go down and look things over. Then we will feel fit for another spell of work."

Accordingly the aeroplane was headed downward. They circled the opening once or twice in order that the pilot of the aircraft might get his bearings perfectly, and then he headed for the ground.

Even as they were just approaching the earth Frank heard Andy give one of his customary exclamations, such as announced an important discovery.

"Frank, there's the biplane in the opening!" was what he cried.

Yes, Frank himself had sighted it now, but the discovery came too late to have any effect upon their movements, since they were bound to land, not having room to rise again, even did they wish to do so.

And Frank, as he felt the wheels under the aeroplane touch the earth, also heard a loud cry and some lusty Spanish expletives as a pistol was discharged.

CHAPTER XXIII : HOMEWARD BOUND—CONCLUSION
As was his usual habit, Andy jumped before the monoplane had stopped. Frank on his part had no sooner seen that everything was going well than he snatched the Marlin rifle from its fastenings. He realized that they were up against trouble of some sort, for those Spanish exclamations told him there must be one revolutionist at least close by ready to do battle.

"Frank, look out, he's got a pistol!" cried a voice, which he recognized as belonging to Perc Carberry.

Just then he caught sight of a figure rushing forward. It was the same man no doubt whom they had seen with Perc in the biplane. They had evidently broken some important parts in landing and ever since must have been busy trying to mend the same.

"Stop!"

When the advancing revolutionist heard this sharp command and saw that he was being covered by a rifle in the hands of the determined looking pilot of the monoplane, he sized up the situation and then raised his hands in a way that meant he surrendered.

"Drop that gun then!" ordered Frank, and as he did so Perc seized upon it with a snarl of joy.

"Now we'll see how two can play at that game, you skunk!" gritted the other, as he snapped the pistol straight at the head of the man.

"Here, none of that, Perc. You leave him to us. He's our prisoner, not yours!" ordered Frank, horrified at the rage which the other had shown.

So Perc found that he did not have any authority in the matter, and that if he wanted to get assistance from his old-time rivals in order to finish mending his airship and get away from so dangerous a locality he must do what they said.

He told about how he and Sandy had been out for a trial spin two days before. That was when Frank and his chum had sighted them from the river. But that very night some of the revolutionists had made a descent on the home of his uncle, who had a cocoa plantation not many miles away from that of Mendoza, seized him and carried him away, as they also did the little airship.

Threatened with dire things if he refused to obey, he had been compelled to go up in company with the man who was now their prisoner, a Spaniard, who had once sailed in a balloon and knew something about that type of aviation, though having much to learn in connection with modern aeroplanes.

Sighting our two Bird boys, of course Perc had known who they were. But the man was positive that they must be spies sent out by the government to learn what the revolutionists might be doing up the Magdalena. And he had threatened all sorts of things, Perc declared, unless a hot pursuit were carried on. Secretly Frank was of the opinion that it would require very little urging to make Perc Carberry do his level best to overtake any aerial craft piloted by one Frank Bird, toward whom he had always felt the most bitter animosity.

After about an hour's hard work Frank managed to get the biplane in decent trim for a flight. He was also able to spare the other some gasoline.

Had he been allowed to have his own way Perc would have left the Spaniard in the forest, where he might have died, being unable to make his way to civilization. But Frank would not hear of it. He obtained a solemn promise from the man that he would not make any further effort to obtain control of the biplane, and then Perc was made to take him aboard. Of course, Frank had made sure that the man carried no weapon and that his revolver was thrown away.

They left the glade in the forest soon after the biplane had started. Perc managed to keep close to the others while they headed off toward the northeast. He did not wholly trust the passenger he was carrying and wanted to remain within call of the three who relied upon the monoplane to carry them to safety.

They could even shout out to each other as they sailed along. Thus Perc warned them when they were approaching a camp of the revolutionists as they drew near the region of the river, and they were able to change their course, not wishing to again run the perilous gantlet of gun-fire.

When another descent was deemed necessary it was close to the Magdalena, though many miles south of the town where the cocoa planters lived.

There was no reason why Perc should also descend, save that he wished to be rid of his unwelcome passenger. The revolutionist might now make his way to camp and electrify his fellows with a stirring account of his various adventures. And one could easily guess that they would lose none of their zest in the telling.

Perc did not expect to halt again when the monoplane was brought down. He could make one flight of it now and reach the home of his uncle, where doubtless Sandy was mourning him as lost.

Just as Frank had expected, Perc on saying good-bye tried to appear as though something along the order of gratitude might be striving to gain a foothold in his crooked nature.

"Say, Frank, I'm sorry now I ever tried to do you dirt," he observed, as he held out his hand. "Let's forget the past and start all over again."

"Sure," replied Frank, as he readily took the offered hand; but it lay like a cold toad in his grasp, as Andy afterward expressed it, for Perc insisted on also bidding him good-bye ere he made a start in his biplane.

"Well, now, what d'ye think of that?" said Andy, as they stood and watched the other mount upward and caught the wave of his hand ere he started down river, being fully five hundred feet high. "Did he mean it, Frank? Would you really want to go so far as to trust that snake if the chance ever came again for him to do you a bad turn?"

Frank shrugged his shoulders.

"Say, ask me something easy, won't you?" he remarked. "Because you know how hard it is for a leopard to change its spots. Perhaps Perc has seen a light; but excuse me if I doubt it. Naturally he felt kind of cheap, because we got him out of a bad hole and placed him under obligations. But that will wear off in a short time."

"Right it will," declared Andy. "I give you my word, Frank, that the next time we see him he'll have a fine story all fixed about how he was just going to jump on that Spanish revolutionary fellow, and twisting his gun out of his hand, shoot him down, and then fly away. Oh, don't I know Perc though? He'll hate us both worse than ever just because he's beholden to us. Rats! him reform? Not much!"

By the middle of the afternoon they had advanced far enough to know that another lap ought to carry them to town, and of course all of them were anxious to have the journey completed.

"If it could only be written up and sworn to," said Andy, enthusiastically, "I reckon it'd go down in the annals of aeroplaning as the most wonderful stunt carried out up to date. But people won't take our word for it."

"We've got the evidence of it, though, in the person of your good dad, and people may believe what Professor Bird says over his own honored signature, however much they might doubt the yarn of a couple of boys," Frank remarked, as he took a last look, to see that both his passengers were snugly settled, ere starting the motor.

"We're on the home stretch now!" declared Andy, after they had again mounted up into the realm of space and found their course northward.

"Yes," observed Frank, "we're homing pigeons now, if any kind of bird."

"At any rate," laughed the professor, "we're birds of passage, and one of them is mighty glad of the opportunity to get back into the old world again."

In due time they sighted the town, and as before, the greatest excitement followed as they headed across the place, looking to land where the journey had begun—in the yard of the cocoa planter's place.

Of course Señor Carlos was delighted with the success of the mission. For two days the Bird boys were the center of an enthusiastic demonstration. Frank was a little nervous lest they be visited by some of the revolutionists, but such did not turn out to be the case. And on the third morning the little steam yacht once more headed down the turbulent Magdalena, with a heavy rain promising more water to add to the flood, as wet weather had seemingly set in again.

They met with no difficulties on the way down. Apparently the camp of the revolutionists had been moved from its former position at the narrows of the river. It might be those in charge had taken the alarm and feared lest a government force must be on the way to capture them, after being informed about the camp by the spies they had sent up the river.

And Barranquila was finally reached, where they halted only long enough to chat a short time with Señor José, who met them as before on the quay and wanted to shake hands with the professor.

Knowing just how anxious the government was to get possession of airships just then, Frank did not want to give them any further chance to confiscate his neat little craft, under some pretense or other. So they left the city at the mouth of the Magdalena and steamed away, bound once more for Maracaibo, where they meant to take steamer for New York, New Orleans or any port in the States.

The last glimpse they had of the river was the flood that was pouring out between the jaws of land marking one of the mouths of the Magdalena and making a distinct yellow area in the salty waters of the tropical ocean.

The beloved little aeroplane had been safely boxed again and was making the homeward voyage in their company. What strange and wonderful things it had been through! Andy declared that they almost passed belief, and he expressed his doubts as to their ever having an opportunity to pilot that same aircraft through atmospheric seas as tempestuous as those they had experienced in the tropics while rescuing the prisoner of the cliff bordered valley. But then Andy was not gifted with second sight and he could not foresee what the wonderful future might have in store for the Bird boys.

They had by this time experienced enough of the fascinating new methods of cruising in cloudland to want to continue. And it stands to reason that other adventures would be lying in wait for lads so constituted.

For the present it must be enough to say they arrived safely at good old Bloomsbury in due time and that the entire population was on hand to greet the party when they stepped from the train. Also, the wonderful little monoplane, the same that had been equal to the test in the race for Old Thunder Top, had to be placed on public exhibition for several days in the town hall, where every man, woman and child in all the country around could examine and comment on the construction of the airship that had brought fame and happiness to Frank and Andy Bird.

In due time Perc and Sandy turned up, minus their biplane, which the government of Colombia had seized on some plausible pretext, though paying liberally for the same. But they were soon at work constructing another, which they claimed would far exceed the one that had been lost.

Professor Bird by slow degrees recovered his health that had been sadly shattered by his experience down in that country. But he declared that his days were over so far as aviation went, and that in the future he must be content to take a back seat and see the honors of the family carried off by the younger generation—the Bird boys. THE END.