TABLE OF CONTENTS

1. Hazardous Flight

2. Pursued by a Flying Foe

3. Tropic Storm

4. Island Prisoners

5. The Cave of Wonder

6. Trapped!

7. Crashed!

8. Jump

ON ADVENTURE ISLAND

CHAPTER I

Hazardous Flight

Flying a mile high above the rolling hills of the countryside, Terry Mapes suddenly put Skybird, her little blue-and-gold monoplane, into a series of loops. She was feeling good, her brown eyes were keenly alive and her slight boyish figure sat erect as she handled the controls of her plane. And being a young and lively girl, she wanted to turn somersaults in the sky to express her joy.

Her twin sister, strapped in the rear cockpit, spoke to her through the earphones, “Quit your circus stunts, Terry, and keep going! We’ve got a long trip ahead of us.”

“You guessed it, Prim. That’s why I’m feeling so full of pep!” answered Terry and her voice died away as she put Skybird into another loop among the clouds.

The next minute her plane was on an even keel and Prim repeated: “Terry, will you stop clowning? Save that pep! You’ll need it before we get to South America.”

“Don’t I know it! I’ll be good and tired before I reach Peru, but right now I feel like a million dollars. I wouldn’t change places with the President of the United States or the Prince of Wales,” said Terry with a laugh. “I’m perfectly satisfied to be Terry Mapes, airplane pilot on a secret errand to the wilds of South America.”

“And I,” interrupted Prim, settling back for a comfortable trip, “would rather be just Prim, the twin sister of the cleverest girl flyer who ever did a barrel roll.—But I wish she’d cut out the stunts for the present!”

Dick Mapes, the father of the girls was an old airmail pilot. He had taught both girls to fly. The home-loving Prim had become a good pilot but she was not as fond of the sport as her sister. Prim was a pretty blonde type, inclined to plumpness, easy-going and gay, while Terry was serious, high strung and nervous, Terry loved to fly and now that her father was crippled from an accident and still unable to leave his wheel chair, she was trusted with many important air jobs.

To Terry it was not half so venturesome to cut up antics in the air as it would have been to race in a motor boat or automobile. She always felt perfectly safe and perfectly happy when she could put a thousand feet of air between her plane and the earth.

Prim, in spite of her protests, had perfect confidence in her twin sister’s ability to handle her plane and whether she was stunting or flying straight. Prim could feel sure of a happy landing and enjoy herself.

At last Terry had worked off her excitement. She leveled out her plane and throttled the engine down to a steady cruising speed. Terry’s success as a flyer was due to the fact that the girl understood her plane thoroughly and treated it with respect. Apart from an occasional burst of speed to work off her excess energy and a few stunts to keep her in practice, Terry kept her plane on a level keel and never overtaxed it.

Mile after mile sped by below them and Terry’s mind was racing ahead to the work she had to do, a mission which might be full of perils and thrilling hazards.

Since the day when her father had started out with such high hopes of success in the venture of The Dick Mapes Flying Field, things had gone all wrong with him. He had obtained an option on a large tract of land at Elmwood from the owner, Peter Langley who lived at a small gold mine in the wilds of Peru, and it was this field that had aroused the envy of his business rival, Joe Arnold.

Most of Dick’s misfortunes had come through the jealousy of this unscrupulous flyer. Joe Arnold was anxious to get control of Dick Mapes’ field, as it was situated near his own and was at a safe point for carrying on his illegal business. If he could once get this field he would be isolated and not run the risk of being seen when loading and unloading his planes.

Joe Arnold was a dangerous rival. He would stop at nothing to carry out his schemes. And for the last two years he had kept Dick Mapes and his helpers in a state of anxiety. At first there had only been slight inconveniences, mishaps that were annoying, but through his agent, Bud Hyslop, who worked as mechanic for Mapes, Joe was able to learn all the plans of the field. He grew bolder and with Bud to carry out his orders, the field was the scene of frequent accidents.

Suspicion pointed to Bud after the crash in which Dick Mapes was injured. Dick was a careful pilot and always checked up on his plane before starting out on a trip. Yet as soon as he was in the air that day, he found that someone had been tampering with his plane. It was too late to save himself. The plane crashed from a height of five hundred feet. It was a miracle that saved Dick from death.

Allan Graham, his young partner, declared that he had seen Bud near the plane just before Dick took off. But no one could say for sure that Bud Hyslop was guilty, although most of the people on the field believed he was. Dick was too tender-hearted to discharge the boy without a reason and it was only after Bud had proven beyond doubt that he was working against the field that Dick let him go.

One thing after another had happened to discredit Dick and for a time it looked as if he might have to give up the field entirely.

And as a final blow word had come from Peter Langley saying that he did not care to extend the option, after he had let it be understood that he would do so. Dick felt as if the struggle was too much for him. Old Peter Langley had gone on to say that he had received reports that Dick was using the field for smuggling purposes, and he did not care to be mixed up with business of that sort.

Dick knew, without being told, who had been the slanderer. His enemy, Joe Arnold was still trying to injure him.

Bennett Graham, his backer, came to the rescue once more and gave Dick the money, but the time limit was almost up. There were only about ten days left. And with Peter Langley believing him to be a crook, there was little hope of taking up the option without a personal interview.

Dick Mapes in his wheel chair, fretted and fumed at the problem facing him. Allan Graham, the son of his backer, and Syd Ames had been his first student-flyers and were now working at the field. They had been gone a week on a trip to Chicago. No one was left to take the long trip to Peru.

Of course he had Terry and Prim! Dick could trust Terry anywhere with a plane, but it was a long flight to Peru and there might be storms and dangers. Dick grew restless and impatient under the misfortune that kept him tied to his wheel chair.

“If I were only well enough to fly!” he fumed.

“But what’s the idea, Dad! Don’t you think I can fly well enough?” Terry faced her father with flaming cheeks, her large brown eyes were flashing. “Why not send me?”

“Send you? To South America? Alone?”

“Not alone! Prim can go.”

“But Terry, don’t you realize that Peru is a long way off? You may have to face grave dangers, storms, fevers, savages! And while Peter Langley and his wife may be all right, you never can tell ahead of time what rough characters you may meet there!”

“What of it? I’m not afraid. You wouldn’t think twice about sending Allan and Syd,” said the girl with a frown.

Dick Mapes shook his head. “That’s different,” he said. “They are boys!”

“Which means that you don’t trust me. You think I’m not a good flyer!”

Dick laughed. “Terry, don’t be silly! I’d trust you to fly anything you could get off the ground. That isn’t it. But I don't feel as if it would be right for me to let you risk your life.”

Terry sat down beside her father’s wheel chair and took his hand. “Listen Dad, while I talk. Haven’t I proven over and over again that I'm a capable flyer. I’m pretty good at getting out of a jam in the air.”

“I’ve said it often, Terry. I’ve never seen a better stunt flyer. You’re clever and you think when you’re in the air! And that’s what half the flyers don’t do. That’s why they crash.”

“All right, so far, so good! We've been in lots of jams and got out of them by using our brains. Weren’t Prim and I The Gypsies Of The Air, and didn’t we go after the boys in Newfoundland and get them away from the kidnappers? Nothing terrible happened to us. Of course old Jim Heron kept us locked up and we had to think hard to find a way out of that old fortress, but we escaped without any harm.” Terry’s eyes were snapping as she recalled their imprisonment in the old fort.

“Oh, I know, Terry. You and Prim can look out for yourselves. But I don’t like to send you into a jam deliberately.”

“But Dad, you don’t know that there will be a jam, this time, and if there is, we can get out of it.”

Dick did not answer as Terry hesitated and gave him a chance. The girl went on:

“Now we’re in one of the biggest jams we’ve ever had yet. We’re almost sure to lose our flying field, though we have the money to take up the option, because our enemy Joe Arnold has written mean letters to old Peter Langley and set him against us. Now you can see for yourself, if I could get down there before the option expires he would think differently.”

“I know he would, Terry. But it’s too dangerous. No.”

“But it’s the only way out. Allan and Syd are not here and may not be for a week. And we are apt to lose our flying field because you still have this one old-fashioned idea. You’re up to date in every other way, Dad. What makes you think that girls can’t look out for themselves?”

“Terry, you should have been a lawyer. You’re wasted in aviation,” her father said with a laugh. “You can make a fellow believe that black is white.—All right, if your mother consents, I will.”

“That’s passing the buck! You’ve got to answer ‘yes’ or ‘no.’ You know it will be a deadlock for mother always says, ‘If you can get your father’s consent, I suppose I’ll have to agree!’ and if that argument keeps up, the day for taking up the option will be long past and we’ll have to give up the field.”

Terry loved a struggle, her eyes were shining as she noted that she had almost reached success.

Dick Mapes slapped her hand playfully. “All right. When do you start?”

“At daybreak tomorrow,” answered Terry in a business-like manner. “The plane needs a few repairs, small ones, then we’re all set to go!” The girl wasted no time. The next minute she was running to the hangar, and drawing on an overall suit was getting ready to look over her plane.

Her mother, Alice Mapes agreed without a struggle. “In fact I don’t feel half as frightened as I did when you went north to find the boys. You’ll have a wonderful trip to the south. Your father and I trust you perfectly, we know you’ll look over your plane at every stop and never take a chance with it.”

“There you see, Dad!” said Terry with a happy laugh. “When mother agrees, it’s bound to be all right.”

Prim was already busy at their flying togs. There were a few repairs to make and this was left to Prim, who liked to sew and cook and do other domestic jobs while Terry was a good mechanic and kept the plane running without a hitch.

“A born flyer!” said Dick Mapes and he followed his daughter’s figure as she tested her plane, listening intently to the hum of the motor, going over every part, making adjustments here and there to bring her plane to the highest pitch of efficiency. And when Terry was satisfied that Skybird was in perfect running order, Dick Mapes could never find a flaw. Terry knew her job.

Bennett Graham had all the necessary legal papers ready and a certified check to close the deal, so there would be no hitch at the last minute. These papers were carried in a small brown leather case and sewn into the lining of Terry’s flying coat.

Prim loved stylish clothes and her white flying suit was smartly cut. Terry turned to admire her pretty blonde sister just before they were ready to hop off.

“What’s the idea of that necklace?” said Terry with a laugh. “Girl flyers don’t wear necklaces with bright red jewels.”

“Don’t they? Well, this one does! It just suits my fancy, Terry Mapes. I think it looks smart, it adds a bit of color to my white costume.”

“All right, Prim, just as you say. Now, is everything set? How about your sweet tooth. Got plenty of cake chocolate?” teased Terry, for Prim was always nibbling at something sweet.

“Sure, my pockets are full. Here put this little package of crackers in your coat. We may get hungry as we fly along. And I’ve put up a big lunch in case we need it.”

At the last minute Prim adjusted the harness of the parachutes about Terry and herself not minding her sister’s impatient shrugs of disdain.

For some reason Terry was always impatient of parachutes. She felt like an amateur even though she knew that many of the big flyers never went up without putting one on, as a safeguard in case of accident.

Terry looked with satisfaction at Sally Wyn, the little waif they had brought with them from the far north. The girl was fluttering about the field like a butterfly. She seemed to be in half a dozen different places at the same time, running errands and making herself useful. With Sally there, her father and mother would not be so lonely. The little orphan had found a place in the hearts of Dick and Alice, and they would not hear of her leaving them to go to work. With her happy disposition she kept the household filled with laughter. Alice often wondered how she had ever been happy without this fun-loving girl. And she had a way of making Dick forget that he was a cripple. She amused him.

As the girls said goodbye to her, Sally called out: “Next year Terry Mapes, I’ll race you to Peru!”

It was a glorious morning, the sun was just rising as Terry sent her plane into the air and headed south. There were no last minute delays.

Now it remained for Terry and Prim to reach Peru, find old Peter Langley and convince him that he was mistaken and make him want to sell Dick the property. And in Terry’s mind there was no doubt that she could accomplish it.

Below them was a vast stretch of fertile country with streams, lakes and broad green valleys. And high in the air, Terry's hand at the controls felt the spring of her little plane and was certain that Skybird was thrilling at the adventure.

Terry held the plane down to a steady speed, hour after hour, only changing the monotony by diving to a lower level or rising to greater heights. They were following along the general line of the airway. They could pick out the landing fields and see the position of the great beacons that would flash at night to guide the flyer to the hangars on the ground.

Terry and Prim had decided to stay all night at the Waverly Field, far to the south. That meant steady flying all day, only coming down to refuel at long jumps.

They saw the lights of the Waverly Field a full half hour before they expected to be there. “Shall we go on?” asked Terry through the earphones. “We can easily reach the next landing field before dark.”

“No, let’s stay here. You look tired and besides I like the looks of this pleasure beach,” replied Prim.

Terry put Skybird into a steep spiral, leveled and circled the field and then put the plane neatly down on the ground.

Little did the girls think as they were greeted by the manager of the flying field that this was where their troubles would begin. That before they reached Peter Langley’s mine they were to face an enemy who was desperate with greed and hate. And that at times the girls would despair of escaping with their lives!

CHAPTER II

Pursued by a Flying Foe

Waverly was a popular beach resort and Prim was delighted to see that there was a pleasure pier which was gaily lighted up.

She cried, “Oh, Terry, it looks as if there might be dancing down there. Let’s hurry to the hotel and change to our party clothes.”

“Prim Mapes, you promised me that you wouldn’t take any party dresses this time. You said we’d be just girl flyers with no excess baggage,” retorted her sister.

Prim laughed. “I tried to Terry, but I couldn’t leave out our new frocks. I was certain we’d run into some sort of entertainment where we’d want some pretty dresses.”

Terry looked her disgust. “But Prim, I don’t even want to dance. What am I going to do with these documents while I’m dancing?”

“You could leave them at the hotel in the safe,” answered the easy-going Prim.

“Just forget that, Prim. Wherever I go, these papers go with me. If you insist on dancing I’ll have to go along, but I'll have the papers on me.”

As the girls talked over their plans they arranged for the care of their plane for the night and for refueling, as they intended to take an early start the next morning. Then they went to the hotel where many summer guests were staying.

Prim made friends easily and by the time Terry had registered for them at the desk and made arrangements for getting away early the next morning, Prim had a group of girls around her and was laughing and joking with them as if she had always known them. Terry envied her sister this ability to get acquainted with people at a moment’s notice. It would have taken her a week, at least, without Prim to break the ice, to become friends with these strangers.

When the two girls came down to the dining room half an hour later, their new acquaintances hardly recognized them. Prim was dressed in a fluffy gown which made her look like a lovely bit of Dresden china. Terry was very boyish and trim in her sports dress. She had an aristocratic manner, attracting notice by her very aloofness.

The dancing pavilion was built out over the water and they could hear the surf breaking about the pier. Prim danced to her heart’s content, for partners flocked about her. But Terry was uneasy for pinned to her slip were the valuable papers she must deliver in Peru. She was relieved when Prim finally consented to go back to the hotel, exchanging addresses and promising life-long friendship with her new friends as she went along.

At the first flush of dawn, Terry and Prim were at the hangars preparing to take off. Terry made a careful check-up on her plane to see that everything was in order and as they were about ready to climb into the cockpits, they heard a shout and their new friends came hurrying to the field to bid them goodbye.

Prim was glad they had come. She wanted to show off her quiet sister who always got her plane into the air so gracefully, and her face glowed with pride as Terry taxied across the field, swung around and headed into the wind for a good take-off. Skybird took to the air like a great bird and under Terry’s guidance circled the field several times for the benefit of their friends, then headed out over the Atlantic, flying south.

They did not know that a plane had been set down on the field half an hour before. The pilot had recognized Skybird and kept well out of sight. As he watched the girls from the shelter of the hangar, his face expressed the hatred and treachery that he felt.

It was Joe Arnold, their father's business rival and dangerous enemy!

“What are those girls doing here? Do they imagine they can fly to Peru and see Peter Langley?” thought Joe to himself. He made up his mind that the girls would never reach Peru. He would stop them, somehow. He must do it.

Joe Arnold frowned. As his plane was more powerful than Skybird, he could easily out-fly them and reach the mine a day before they could do so. But, first, he had some mysterious business to attend to before he would have the money for the option. Meanwhile he must do something to prevent the Mapes girls from continuing their trip until he was ready.

Before Skybird had disappeared in the clouds, Joe Arnold had left the field and was following after that tiny speck in the sky, trailing it relentlessly.

The next stop was Miami, and here again the girls made a thorough inspection of their plane. From now on their way would be over the Caribbean, where storms might spring up without warning. Skybird must be in perfect form. And when Terry finished her inspection, the little plane was ready for the hop to Havana.

The girls congratulated themselves that everything was going along well. They were even a few hours ahead of their schedule and Terry’s face was glowing with happiness and excitement. Ahead of them was the Caribbean. She had often dreamed of making this flight over tropical waters and now she was really here.

Below her were the keys and reefs of the Florida coast spread out flat on the blue water. They were like a painting in delicate pastel shades. Crossing the line of the reefs, Skybird headed boldly out to sea. Prim watched the smooth water, fascinated by the patterns made by steamers as they cut through the water, leaving an ever widening wake behind them. She felt safe, knowing that their amphibian plane could land on the water and float.

Terry sighted the coast of Cuba first, a delicate outline seen through a haze that dimmed the view and gave it a fairy-like appearance. Soon they sighted the grim old Morro Castle, the Spanish fort, and as they came nearer and flew above it, they could see the broad avenues of the lovely city of Havana. The marble capitol was dazzlingly white in the sunshine and the colored roofs of the houses, as seen from the air, arranged themselves in a fantastic design. It was a city of gay pleasure.

Terry brought her plane down at the Havana airport with a sense of relief. The first lap of that journey was over now.

A few minutes later she was handed a telegram which read: “Allan and Syd will join you at Havana. Wait. Dad.”

Terry’s eyes blazed for a moment. “What do you think of that, Prim? Allan and Syd are coming here. We’re to wait for them! I’ll say that’s nerve! Dad thinks we can’t make the trip without the help of the boys.”

“That’s nonsense, Terry! Dad knows we’re equal to it. The boys probably want a holiday and are coming just for the fun of it. I’m going to be real glad to see them. The more the merrier, I say,” replied Prim.

“I’d be glad to see them if I thought that their trip was not just because they think that we have to be looked after,” declared Terry. “I want to make this flight without help from anybody.”

“Don’t get too independent, Terry. It doesn’t pay,” her sister cautioned her. “But right now let’s go and get some breakfast. I’m starved.”

After they had finished with the customs and entry regulations the girls started toward the restaurant. A plane was circling about their heads looking for a landing.

Suddenly Terry grabbed her sister’s arm. “Oh Prim, look there! It’s Joe Arnold!”

“Where did he come from? What’s he doing down here?” demanded Prim, as if her sister knew all about Joe Arnold’s affairs.

Terry laughed nervously. “Ask me something easy! But of one thing we can be sure. Whatever it is that has brought Joe Arnold down here, it’s bound to be crooked, whether he is on business of his own or just trailing us. That man couldn't be decent!” Terry said with indignation.

“What are we going to do, Terry?” asked Prim.

“We are going to do nothing at all, except keep our eyes open,” answered Terry as she slipped back to the hangar and spoke to the mechanic who was looking over her plane. She gave him her sweetest smile as she spoke to him. “Keep your eye on my plane. Don’t let any stranger near it.” And she gave him a five dollar bill.

The young man promised and as Terry turned away he smiled to himself. “Guess she’s new to the game,” he thought. “Afraid someone will want parts of her plane for souvenirs.”

“Come on Terry, hurry. If you only knew how hungry I am!” cried Prim. But now another plane had approached and made a neat landing.

Prim stopped short and grabbed her sister’s arm. “Oh Terry,” she cried, “I’m almost sure that’s Allan in his new plane.”

“You’re right. That’s Allan! And Syd is with him!”

A few minutes later Allan and Syd leaped from the cockpits and were waving to the girls with whoops of delight. Terry and Prim hastened back across the field to welcome them.

“Hurry up!” cried Terry. “Prim is starving!”

“She’s got nothing on us,” Sid answered. “We could eat our shoe strings,—almost!”

When they were all seated at breakfast, Terry suddenly turned to ask Allan, “What’s the idea of trailing us down here? Are you taking a vacation?”

“A sort of vacation,” answered Allan. “About an hour after you left the other day, Syd and I got home. We finished up our business in half the time we expected. Then we heard some reports. Joe Arnold had been back at the field and was bragging around that he was starting out to make the final deal with Peter Langley for your father’s flying field. He sent notice to your father to vacate the field.”

“Why the nerve of that man!” cried Terry. “He’ll do no such thing! I won’t stand for it!”

“Anyway,” went on Allan. “We found out that Joe had started south and your father wanted to warn you, so he sent us. And here we are.”

“Yes,” Terry broke in. “And Joe Arnold set down his plane at the Havana airport just a little while ago. I’m sure he saw us. Even if he didn’t he’d recognize Skybird. That man is up to mischief.”

“Do you think he’s going to try and make trouble for us?” asked Prim anxiously. “I’m afraid of that man, after what he did to you boys in Newfoundland.”

“We are not going to worry about it,” Terry announced with decision. “We are going to keep right on at the job we set out to do, and trust to luck to get us through safely.”

The four friends had an excellent breakfast with tropical fruits and delicious Cuban dishes. At times they forgot all about Joe Arnold and his threats to take away their father’s flying field. It was good to be together in this romantic city of Havana, and hard to realize that danger threatened them.

All about them were smartly dressed care-free people, spending money lavishly on the pleasures of the gay city. People came here from all over the world just to enjoy themselves.

But Terry would not allow them to forget that a difficult job lay ahead of them. It was necessary to push on. Consulting their maps, they laid out their route. The next hop would be across the open waters of the Caribbean to the landing field at Gracias a Dios in Honduras. That would be their next meeting place in case they became separated. Allan and Syd had planned to see them safely through the treacherous tropical weather of the Caribbean, before returning to Elmwood. Now that they were tipped off to the fact that Joe might make trouble, Terry could be depended on to keep her eyes open and avoid him. But the boys decided they would watch Joe and find out what he was up to.

The weather reports were favorable. There was always the warning to watch out for sudden storms that were common over the Caribbean.

Their take-off was delayed by Terry insisting that her engine was not working properly. Allan came alongside to listen as she warmed up the motor. “Why it sounds all right, Terry. I don’t hear anything wrong,” he said.

“But listen!” shouted Terry. “Listen to that rough hum.”

“You’re right, Terry,” said Allan as the girl shut off her engine and got out. Slipping into her overall suit, she started to work.

“Has anyone been near my plane?” asked Terry of the young mechanic whom she had warned.

“No. That is nobody touched it. There was another flyer who stood around admiring it and asking who you were. He even wanted to know where you were going. Then he said he’d like to take a look at your engine to see what kind you had. But I didn’t let him stick around,” replied the youth. “I told him to clear out!”

Allan and Terry got to work without waiting for further explanation. A full hour went by before they had the engine humming smoothly enough to suit the trained and sensitive ear of Terry Mapes.

Once more they were ready to take off. Terry taxied over the long field, making sure that the engine was working properly before she pulled back on the stick and sent Skybird nosing into the brilliant blue sky.

Terry’s heart was beating with happy excitement. The take-off never became a commonplace occurrence to her. She thrilled as she felt the ship lifting from the ground and in the face of the wind, rising to dizzy heights above the earth.

Allan and Syd followed and for half an hour they flew at about the same altitude. Then Allan lagged behind and rose above them to a height of five thousand feet. Both flyers were watching the sky behind them to make sure that their enemy was not in pursuit.

Joe Arnold had put in a busy morning in Havana. Here was where he had some shady business that would give him the ready money for taking up the option on the Dick Mapes Flying Field. And when he started out half an hour after the other planes, he flew high and well out of sight.

Terry and Prim were content to fly at about two thousand feet. They were enjoying the view of the southern sea dotted with islands and failed to see the pursuing plane, high above them in the distance.

But Joe Arnold was watching intently every move of the two planes, and the cold, menacing light in his eyes was a threat against these young flyers who dared to upset his plans, and keep him from realizing his ambition.

His mind was working fast. At the next flying field, he would have a show-down with them. His business deal in Havana had not been successful. It would be necessary to return to that city once more before he got the money. Joe Arnold did not know just what kind of a show-down he would have with these girl flyers. He would leave it to chance and his usual good luck unless he could think of some plan as he flew through the blue sky. Up in the clean air of the heavens this man was planning to destroy them.

But Terry and Prim, unconscious of his plans, were watching the changing colors of the islands, then faced once more the open sea toward Honduras.

CHAPTER III

Tropic Storm

High above the sapphire mirror of the Caribbean, Terry kept her plane in a southwesterly course. The sun was a pitiless ball of flame that sent out long fingers of fire. It was tropic weather.

Above them Allan’s plane was soaring ahead now. The sight of Joe Arnold at Havana had made them fear an attack, and the four flyers were watching to see whether a third plane was following them.

Leaving the islands behind they flew out over the sea, a great expanse of deep blue and purple water.

Suddenly Prim called to her sister. “Look Terry, there’s land over there, away to the left.”

“Yes, I see,” answered Terry. But she was watching the horizon with anxious eyes. That dark purplish mass looked to her like a low-lying cloud. There was something unnatural about it. Its color was changing rapidly to a reddish hue.

“I don’t like the looks of it, Prim,” called Terry. “See how the light is changing.”

A reddish haze had spread over the whole sky, the sun appeared like a great disc of hot metal. The sight was weird and menacing.

“What’s the matter, Terry? Is it a storm?” Prim asked.

“Yes, a tropic storm. We’ve got to race it. Where are the boys?” Prim leaned over the cowling and strained her eyes to the sky, but that strange and terrifying haze had blotted out the other plane. Terry circled and banked in an effort to find their friends. Then, opening the throttle wide, the girl sent her plane straight before the storm. It was her only chance. If she could out-race that storm, she would be saved.

Sending her plane ahead and in a gradual rise, the girl tried to get above the haze. These tropical storms often covered only a small area, but very soon she realized that the cloud was coming on and rising faster than her plane.

Below them the sea was still visible, a dull lead color now with greenish tipped white-caps. The wind had not reached the plane yet and the girls hoped that they might be able to keep ahead of the tempest.

Then it came, first with a gust that made the little ship bob and dance about. Terry knew this was only the beginning. The storm was upon them! The next deep breath of the hurricane would threaten their lives with its fury. Terry held her plane to the only course she dared to take. She was racing for dear life!

The throb of the motor told that the engine was being strained to the limit of its power. There was no time to lose. If the girls were to escape destruction, they must take that chance.

When the full force of the tempest struck the plane, it was tossed about like a straw in the wind. Under less experienced hands than Terry’s the plane would have crashed. Terry could feel the craft being shaken as if a mighty hand had taken it in its grip, as the gusts of wind struck vicious blows at the wings.

Terry’s grim face was set with determination. But her hand on the stick showed no sign of her fear, it did not tremble or lose its power to control. She was glad now that her father had insisted on training her in all the stunts of the air, for there was no possible position that her plane would take that Terry had not put it into deliberately above her own flying field, and brought it out safely.

But this was altogether different. There she had put the plane into those dangerous positions, now she was being forced into them and she never knew what was coming next.

Terry knew the danger she was in but she felt no panic. Every nerve was tingling, every sense alert. She knew she was doing her best. Her head was clear, her hand was steady and she kept the little plane, climbing, ever climbing.

The girl felt that Skybird was fighting for life, with what seemed like human intelligence. It shuddered and shook and it seemed to try to right itself after a gust of angry wind.

Prim clung to the cowling, terrified yet fascinated as she watched her sister. At times it seemed as if the plane had turned clear over, as if it were going down in a tail spin, but the next moment Terry would bring it up for a second. It was a big fight.

“She’ll win,” thought Prim. “She’s wonderful!”

Only for a second did Terry lose hope of victory. There was a sputtering of the engine that her trained ear heard. It sent a chill to her heart. Her hand shook. She gave a frantic glance back to see if Prim had heard that menacing sound. And that one look showed her a clear space in the dark masses.

The storm was passing. Terry held to the controls, praying that the engine would hold out until the wind ceased.

Suddenly Terry was able to put her plane into a steep climb that brought her above the storm. Coming out of that black cloud Terry saw Allan’s plane ahead of her. She followed it, her heart singing for joy. A mist came to her eyes as she realized that it was only by a miracle that both planes had gone through the storm and survived.

Terry signalled with the wings of her plane and was answered in the same manner. She followed Allan's lead, hoping that her engine would not go back on her. At intervals she heard a sputter that terrified her, but now the sky was clearing. She felt hopeful.

Allan finally headed east. This was strange. Terry looked at her compass and a frown came to her face. What was Allan doing? He was going far out of his way. At last she understood. Away in the distance was an island. He was going to land. She wondered if he were having engine trouble.

Terry did not dare to open her throttle wide. Any extra strain might be her undoing. But, as she neared the small island the plane ahead banked, circled and signalled, then went into a dive for landing on the far side of the island.

Terry tried to follow but the engine was sputtering once more. She made a long dive which brought her amphibian into the water at the near side of the island. There was a broad strip of sand and Terry sent her plane cutting through the spray on to the beach.

“We’re safe!” cried Prim as she nimbly stepped from the cockpit, followed by her sister. “Wasn’t that an awful storm?”

“It’s just luck that we’re alive. Now let’s go over and see the boys. It looks as if they might be having engine trouble, too,” replied Terry.

After making fast their plane by a rope to a palm tree at the water’s edge, the two girls scrambled up over the rocky ridge to the low summit. The island was narrow at this end and soon they were looking straight down upon a sheltered cove where the boys had landed and saw the amphibian floating on the water. A launch shot out from the shore and when it reached the plane, several bundles were dropped into the boat by the aviator, who then got out of the plane and was taken ashore.

The girls looked at each other, distress on their faces.

“We’ve followed a plane, but it’s the wrong one!” cried Terry. “What a stupid thing to do! Prim, how can you ever trust me again?”

“But I thought it was Allan and Syd, too,” replied Prim. “Never mind, these men will help us fix our plane and we’ll be off in an hour or two.”

With a wave of his hand the aviator started upward toward the summit where the girls stood.

“He seems to be friendly,” commented Terry. “But let’s wait here to greet him. How he’ll laugh when I tell him that I thought I was following another plane.” The girls waited at the summit until the stranger came up the winding trail. As they heard his footsteps Terry moved forward to speak, then grabbed Prim’s arm with a nervous grip. The man had come out on the summit and was staring at them with a triumphant grin. His eyes were glittering with a fierce and cruel light that made the cast in his eye more pronounced. It added to the sinister look in his face. The man facing them was Joe Arnold!

A moment later the girls gasped with dismay for their old enemy, Bud Hyslop, came shambling up the trail.

“Well, look who’s here!” said Bud and added sarcastically, “this is a pleasant surprise!”

But Joe silenced his rough-neck follower with a scowl and a low snarl. “Don’t get funny. Shut up!”

Joe Arnold, with menace in his voice, addressed the girls, “Why did you come here?” he demanded. “What do you want?”

Terry stammered for a second then answered: “I was having trouble with my engine after that storm and I knew I’d have to come down, so I followed you here.”

Joe stared at the girl and shrugged his shoulders. “That sounds fishy to me. I think you’re trying to spy on me. What brought you away down here?”

“We’re on a vacation,” answered Terry. “We are on our way to the Canal Zone.”

Joe Arnold watched the girls contemptuously. “I don’t believe you!” he said. “I think you came here to watch me.” Suddenly he turned to Bud. “Go on down there and see what’s the matter with Terry’s plane.”

“But I’d rather fix my own plane. I’m used to it and can fix it in a minute. I know exactly what’s the matter.”

“No! Let Bud go as I told him! You stay here!” There was a note of command that frightened the girls. Prim touched Terry’s arm and said softly. “Careful Terry, don’t make him angry.”

Terry gave her sister a grateful smile. She turned to Arnold and asked pleasantly. “Did you get into that storm?”

“No, I knew too much to let that happen. I saw your plane go into it and thought you were done for,” he answered.

“How did you avoid it?” asked Terry.

“I was flying high, fifteen thousand feet. It never touched me. The storm was all below me. I’m used to these hurricanes and I can usually guess about how far the storm extends.”

“I tried to get above it, but I didn’t go far enough.” Terry was watching Joe’s face while she was talking. Would he guess that she was carrying an important paper for Peter Langley? Would she be able to keep it hidden where he could not find it?

Now it was safely sewn once more in the lining of her flying coat but that was not a good hiding place if he thought to search her.

A sudden shout from the harbor sent Joe Arnold hurrying down the trail. Then he turned back. “Stay right where you are,” he ordered the girls. On second thought he said. “No, go on down the trail ahead of me.”

“But I don’t want to go!” flared Terry.

“If you’re wise you’ll do as I say!” Without another word he thrust the girls ahead of him toward the beach.

Terry went without any further argument. For suddenly it had occurred to her that she might learn something of Joe Arnold’s schemes if she pretended, to be friendly with him and didn’t make him angry.

At the harbor a gang of blacks were loading a boat, preparing to take it to the plane. Pedro, the chief was over six feet tall, wore only a loin cloth and looked half savage. This giant was watching his men, who were working for Joe Arnold. Pedro seemed to have a few words of English but he spoke to his men in a mixture of Spanish and his own language.

“What terrible looking savages!” whispered Prim. “They look as if they might be cannibals.”

Terry laughed to conceal her fear. “I could even stand having a cannibal around if I were sure that Allan and Syd had come through the storm. They were flying higher than we were but I’m afraid they weren’t high enough, even then.”

Terry was looking about her taking stock of the camp, which was composed of mud huts, and several shacks that had evidently been built recently. On the trail loomed a tall, weathered rock. Terry was pointing out to her sister a great crevice in this stone and explaining the formation of that wide fissure when Joe Arnold turned and saw her. His face flushed angrily. He gave a final order to the black leader and then signalled the girls to precede him up the trail.

“This is no place for you, after all. I shouldn’t have brought you down here where those savages could see you. They belong to a fierce tribe of natives living in the clearings in the jungle. Pedro, the chief, that big fellow, lives in one of my mud huts down there, so you’d better keep away.” Joe Arnold was nervous and stammered as he talked.

As they reached the summit once more Terry took a good look at him, and saw that he was agitated.

“Evidently there is something down there that he doesn’t want us to see,” whispered Terry to Prim as soon as she could do so without Joe hearing her. “When I was interested in that big fissure in the rock, he was scared stiff. I’d like to find out what he’s got down there that he doesn’t want me to see. I'm going to find out! Just watch me!”

“Please don’t, Terry! What do you care about his affairs? We’ve got troubles enough as it is. How are we ever going to get away from here? How will we fly to Peru with Dad’s papers? My head is whirling with problems and all I want to do is to get out of this jam as quickly as possible.” Prim ceased whispering as Joe came closer.

Terry was looking toward her plane. Bud Hyslop was busily testing the motor. The girl could not bear the idea that Bud should touch Skybird.

“If you don’t mind, I think I’d like to do my own repair work, Mr. Arnold,” said Terry with as polite a smile as she could muster. “I’ve always done my own overhauling and somehow, I’d rather attend to it myself. It’s very kind of you to want to be so helpful, but please tell Bud to leave my plane alone.”

As she started toward the beach where Skybird was standing, Joe Arnold stepped ahead of her. “Now don’t bother yelling and carrying on for there is no one around to hear you except some savages and they are my men. I’m boss here, and I tell you to keep quiet. I’m giving that plane to Bud Hyslop. It’s his from now on.”

“You’re giving him my plane!” stormed Terry. “You have no right to do that!”

“Is that so? Well, I’m taking the right!”

“But what about us? How can we get away?” cried Prim, almost in tears. “If you take our plane, we’ve got to stay here.”

“That’s it exactly!” Joe sneered. “Here you stay until I get ready to let you go.”

He stared at them coldly then turned and walked away.

CHAPTER IV

Island Prisoners

Prisoners on a desert island!

Dazed by Joe Arnold’s brutality, Terry and Prim looked about them for a way of escape, but there seemed no way out. Apart from the few huts in the cove where Joe Arnold had his camp, there was no sign of life. They were alone and at the mercy of these unscrupulous men who had every reason to destroy them.

Prim clung to her sister with a grip that hurt. “Whatever will we do now, Terry?” she asked in a hoarse whisper. “We’re up against it for sure.”

But Terry did not hear her. She was watching with flashing eyes as Bud Hyslop worked over the plane. The next instant she was running down the slope in frantic haste with Prim at her heels.

“You let that plane alone, Bud Hyslop! Take your hands off!” Terry picked up a large stone, raised it above her head and with a wide sweep of the arm, she started to throw the missile, but at that moment her hand was seized from behind and a low, mocking voice said, “Not so fast, young lady!”

Terry turned to face Joe Arnold.

“Let me go!” she demanded.

Joe Arnold released his grip with a vigorous shove that sent the girl spinning across the sands. Prim caught her as she staggered.

“Terry, listen to me,” said Prim with decision in her voice. “I don’t know what we are going to do, but one thing sure is that you mustn't make that man angry. He’s capable of anything. He’d think nothing of leaving us here to starve. He’d even kill us if it suited his purpose.” Prim shook her sister’s arm. “Don't talk to him at all if you can’t do it without getting angry.”

Terry was deathly white, not from fear but anger. “But look, Prim! You don’t seem to realize that Bud is going to take our plane away from us. Now we’ll be real castaways!”

Prim searched the sky. “Oh, if Allan and Syd would only come! I’m afraid something terrible has happened to them. I didn’t see them after the storm struck our plane. Where did they go?”

“Don’t talk about it, Prim. Let’s get busy and do something so we won’t have time to think. I don’t dare!” Terry said with trembling lips.

The girls stood watching as Bud and Joe wheeled Skybird around to head away from the beach and over the water. They started the engine. It coughed, it wheezed, it sputtered but at the same time the amphibian taxied over the smooth blue waters and took to the air. Skybird was flying away without them.

Joe Arnold waved his hand toward the departing plane, then turned and climbed the hill, looking back at the girls with a triumphant grin, far more menacing than an angry scowl would have been. Terry knew that he had never forgiven her for her part in the rescue of Allan and Syd when he had kidnapped them in the far north.

Now was his great opportunity to settle matters once for all. This was his chance. He had them at his mercy.

Everything had worked out to Joe’s advantage. Bud's plane had been wrecked some weeks before and on that account they had worked under a handicap, waiting to replace it. Now a fine little plane had miraculously dropped from the sky at their feet.

Joe Arnold smiled. “Luck comes that way to me,” he said to himself. “I have a few bad breaks, but often they work out for my good. If I had succeeded in getting the Dick Mapes Flying Field six months ago as I planned. I’d never have started this island base. At least not so soon.—And this has turned out to be the best graft I've ever struck.”

Bud Hyslop had flown Skybird around the tip of the island to the quiet waters of the little harbor. The engine was sputtering and protesting but Bud was able to bring the plane down safely on the shore. As he turned to Joe, he saluted and exclaimed, “That was some trick you played! How did you do it. Chief?”

Joe Arnold laughed heartily as he answered: “They thought they were following Allan Graham’s plane. I’m almost sure that the girls were starting out to go to Peru to see old Peter Langley. When I was up there Allan and Syd were away. Probably when they got back they learned that I was heading south and decided to catch up with the girls and go with them as a protection against me.”

“What happened to the boys?” asked Bud.

“That’s the joke. Allan’s and Terry’s planes both got into a storm. I didn’t see Allan’s plane when it was over, so I hope he went to the bottom of the Caribbean. Terry didn’t see it either. But she saw mine and followed me, thinking it was Allan.”

“That was a neat dodge. How did you ever happen to think about it?” Bud not only thought his boss was smart, but took pains to tell him so.

Joe Arnold might have told Bud that he had not planned the ruse and that it had been entirely an accident. But instead of that he looked wise and said. “I think fast! That’s how I always win!”

Meanwhile his two captives had taken shelter from the sun under a spreading tree.

“How I’d like to down that man!” exclaimed Terry with blazing eyes as she watched Joe Arnold’s figure disappear. “This is certainly the worst jam we’ve ever been in.”

“And Terry, this time there’s no way out that I can see,” said Prim, her body trembling with fear and nervousness.

But Terry was in a fighting mood. “There is a way out, I’m sure of it, and what’s more I’m sure we can find it! I had to bite my tongue to keep from telling Joe what I thought of him. He looked so smug and self-satisfied because he put something over on us.”

“You did well, Terry, not to talk to him. I was scared stiff you’d fly out at him.”

“I probably would have if you hadn’t gripped my arm the way you did. Sometimes you spoil a good scrap that way. It might have done Joe Arnold good to know what people think about him.”

Suddenly a loud shriek broke the silence of the island. Terry and Prim clung together but the next minute Terry pointed with a smile to two brightly colored macaws above her head.

“Did you ever see anything as gay as those birds? Aren’t they beautiful!” exclaimed Terry.

“I’d like them better if they wouldn’t squawk so loudly,” said Prim. “I do believe they have scared me out of a year’s growth.”

The macaws shrieked again as if protesting at the intrusion of the girls. Other strange birds took up the challenge and answered until the air was filled with their noise.

“Let’s go!” said Terry with the faintest glimmer of a smile. “They don’t seem to appreciate the honor of our company.”

Hand in hand the girls climbed the ridge but kept out of sight of Joe’s camp. Below them and around a sharp point of rocky shore, they looked down over a forest of tropical trees, tall, slender stems and around the lower part of their trunks wound a thick tangle of vines.

“I wonder if we will ever get out of here alive, Terry?” whispered Prim in a strained voice. “You’ve read stories of people who were stranded on desert islands and lived there until they were old and ready to die.”

“Well, this wouldn’t be such a bad place to live,” answered Terry. “If we had the family here and a nice house and books and things.”

“But I don’t like the idea of starving to death and that’s what we would do here.”

“We couldn’t starve to death! Look down there, I’ve been waiting for you to say something. Those trees to the right are bananas, your favorite fruit!”

“I’ll say so! Let’s go get them. I’m starved!” Suddenly Prim stopped short. “Terry,” she said hopefully, “could two girls live on bananas all their lives?”

“Possibly, but we wouldn’t need to go on a full banana diet. There are cocoanut palms!” replied Terry.

Prim brightened up. “And if it comes to the worst, we will try to catch some fish.”

“Fish!” cried Terry. “You know I hate fish!”

“Well, clams, oysters! We might find them here!”

“They’re even worse,” Terry declared. “You can have my share. I’ll stick to bananas.”

The girls were clambering down the rocky ridge to the clearing. As they found their way around a thick mat of low-growing bushes, they came suddenly upon a collection of mud huts. They were among them before they knew it.

The girls drew back to the shelter of the vines, half expecting to be surrounded by a howling mob of savages. But not a sound came from the huts. Everything was quiet. No sign of life!

“Here’s where we’ve got to watch our step, Prim! Savages have a way of hiding in ambush and shooting poison arrows at their enemies,” whispered Terry.

“But we’re not their enemies. We’d—why Terry, we’d try to like them if they’d give us a chance,” Prim was looking anxiously around the shrub as she spoke.

Terry started to tiptoe toward the mud huts, although it was not necessary to guard her footfalls, for the soft green floor of the jungle gave back no sound. Prim tried to pull her sister back but Terry jerked away.

“Come on. We haven't any need to worry yet. This place is deserted. Look at those old mud huts, they are half destroyed by the rains.” Terry drew her sister with her as she peered into every hut as she passed.

“Look at those huts ahead. They’re altogether different. See how they’ve twined roots and vines and twigs together. They’re like great birds' nests. I think that is a clever idea! I wonder if these houses belonged to the chief and his family?”

“Come on in and make an afternoon call.” Terry laughed as she ran toward the doorway, then sprang back in terror.

“What’s the matter, Terry? What did you see?” cried Prim, clinging to her sister’s arm.

“Somebody was in that hut. I saw a child! It was a little one!” said Terry, then suddenly she broke loose from her sister and went once more toward the hut.

“Watch out, Terry,” cried Prim. “Children are apt to scream and that will bring the whole tribe down upon us.”

At that moment Terry burst into a happy laugh, a little face was peering around the side of the opening. A curious, wise little face that was wrinkled and hairy.

“It’s a monkey!” exclaimed Terry with relief. “Only a cute little monkey!”

“Isn’t he funny?” Prim was choking with laughter which she tried to hide, for the little creature looking up at them seemed so human that the girl felt she was being rude to laugh in its face.

Terry had a happy thought. She felt in her pockets and brought forth a little package. There were half a dozen crackers left from the supply Prim had provided.

“Say Terry, what’s the idea! Don’t feed him crackers. Are you crazy?” pleaded Prim.

But Terry was approaching the little animal and offering a bit of the cracker. The monkey shrank back, but only for a second. His curiosity was too great. As Terry dropped the morsel beside him, he grabbed it quickly and with a sudden leap slipped by them to the refuge of a tall tree. Then he devoured it greedily.

“Don’t be too generous, Terry. We may need every bite we can get before this jam is over.”

“All right, but I thought I’d better start by making friends with everything on the island. He’s a nice little fellow. I wouldn’t be surprised if he’d get quite friendly.”

The monkey stared down at them with interest and when they moved away he scrambled to another tree nearer to them.

“Just watch him,” laughed Prim. “Terry, you’ve made a big hit with that fellow.”

“It’s pleasant to find one friendly creature on the island. Come on and let’s see what the inside of these woven houses are like. I’m not anxious to sleep out in the open. I think I’ve heard something about the moon in the tropics making people crazy.” Terry led the way into the hut as she spoke, “Why, it’s not so bad, we might manage to sleep in here.”

“There’s nothing else to do. I wouldn’t want to take any chances with the moon,” said Prim. “We have troubles enough now without losing our minds.”

Terry laughed. “I guess you’re right. We’ll need all our wits to get ourselves out of this jam, and we’d better not get them addled.”

Terry’s laugh had relieved their taut nerves.

“If I could only be sure that Allan and Syd were safe, I could even take this disappointment and get some fun out of the situation. I’m really not frightened of Joe Arnold,—very much!” she exclaimed.

If Terry could have heard the conversation between Joe Arnold and Bud Hyslop at that moment she might have feared them, for Bud had just asked, “What are you going to do with those girls? One thing sure they’ll never leave this island alive, if I have my way.”

Joe Arnold turned on him with an angry snarl. “You haven’t a word to say here! What’s more you never will have. Just wait until you get your orders from me. I’ll see that they don’t get back to civilization for a long time, perhaps never, but I’ll settle with them in my own way and when I get ready. I want no suggestions from you or anybody. You understand? I’m boss here on this island!”

“Yes, that’s what I meant,” replied Bud Hyslop.

“And if they come into this camp just keep your eye on them. Especially Terry! She was here about two minutes and was nosing about the big rock as if she knew I had things hidden there,” snarled Joe Arnold.

“Did she see anything?” asked Bud.

“No, I got her away in time, but if she comes back she is apt to go right there. And if she’d ever get hold of those papers, we wouldn’t be safe anywhere.”

“Do you think Terry suspects and will try to get hold of them before they get away from the island?” inquired Bud once more.

“They’re not going to get away. At least not until I’m safe.”

But Terry and Prim knew nothing of this threat against their lives. They went about the preparation for the night and their greatest fear was from animals and insects that were strange and terrifying to them.

“I’m awful hungry, Terry. Come with me to get some bananas,” said Prim as she started toward the clearing.

“They look green to me, you’re apt to get good and sick if you eat them. Prim. I don’t think I would,” cautioned Terry.

“I’m sick now, I’m so hungry, so it won’t hurt to be a little sicker,” answered Prim as she reached up for one of the green bananas. “Anyway I think they’re ripe.” She passed one to Terry, who stripped back the skin and bit into it.

Terry rolled her eyes ecstatically. “Prim, we’re in luck! I’ve never tasted anything so good in all my life. I’m sure I could live on bananas like these. Now, I know we won’t starve to death.”

Suddenly Prim caught her sister by the arm. From the clearing they could see a strip of the sea and across their line of vision came a small tramp steamer. It was headed from the south and was making straight toward the island.

“Now’s our chance! We’ll signal them and they will come to the rescue.” Prim was trembling with excitement. Together they ran to the top of the ridge. The heat was intense but the girls carried their flying coats with them, hoping that they would have a chance to escape.

The girls waved their hands toward the steamer, but their hearts sank as it steamed past the headland and turned toward the harbor. On the shore of the cove great preparations had begun. A launch was put out from the beach and made toward the ship. Bales were dropped into the boat and taken ashore. A dozen trips were made with loads of food in cases, gasoline in metal drums and bale after bale of goods.

“Whatever does it all mean?” asked Prim in her sister’s ear.

“It’s my opinion,” declared Terry, “that every word we’ve heard against that man is true. Someone said he was a smuggler. Now I believe it.”

Joe Arnold was busy directing the blacks as they stowed away the bales in the old mud huts in the camp.

“What kind of smuggled goods would come in bales?” asked Prim. “I can’t imagine what it can be.”

“It might be lots of things, but probably it’s silk. There’s big money in that,” explained Terry.

Terry did not voice all her thoughts. She was thinking that they had very little chance of getting back to their homes with the secret of Joe’s smuggling base known to them. She realized that the situation was far more serious than she imagined. He was not merely attempting to get the flying field away from her father. Joe Arnold was mixed up in a crooked business. He would take desperate means to keep them from getting back to tell where his smuggling hang-out was situated.

Terry started back down the slope, dragging Prim with her. “Come away, I hate that man! I don’t want to know what he’s doing.”

Night was fast approaching and the girls watched with dread the shadows creeping down over the jungle. They put their heavy flying coats on the ground, gathered large banana leaves for pillows and decided to sleep out in the open.

But no sooner had darkness come than weird sounds filled the jungle behind them. Crickets shrilled in the trees. Wild animals howled and slinking forms scurried by at the edge of the forest. Frogs kept up a continual, deafening chorus, and there were shrill cries of night birds. Terry and Prim held each other closely and stared into the darkness toward the jungle, trembling with fear.

“Look at the sky, Prim,” said Terry trying to keep her mind from the strange and terrifying sounds of the tropical night. “You can see millions more stars down here than we can at home.”

But even the brilliance of the moon could not hold their attention for long at a time. The rustling sounds all around them made their hearts thump.

“I can’t stand it out here, Terry! Let’s go into the hut,” Prim pleaded in an anxious voice.

Although the noises continued, the girls felt a certain protection when inside the four walls, even though the opening in the front was no protection at all.

“Now Prim, I want you to go to sleep and get some rest, and I’ll watch. In an hour and a half I’ll waken you and you can take your turn.” Terry took Prim in her arms as if she were a small child.

Prim burst into tears and threw herself on the floor of the hut, burying her head in her sister’s lap. Terry stroked her head soothingly. And Prim was soon fast asleep.

When the hour and half was up, Terry did not have the heart to waken Prim. She looked pale and tired. Moving her head to the pillow of banana leaves, Terry lay down beside her. She had no desire to sleep.

Once she thought that some small animal had come into the hut. She sat up and strained her eyes into the dark corners, but could see nothing. The moon had set and the black night seemed a protection after the bright moonlight. Terry grew very drowsy. She had no energy with which to waken Prim.

The next thing Terry knew it was broad daylight. The sun was already sending its fiery blasts toward the earth. Prim was still sleeping; she had never stirred.

Terry sat up suddenly. In the doorway was a woman, a black savage. The girl’s heart stopped beating for a moment. The strange creature stared at her and then giving forth a loud, weird, throaty call, she clapped her hands to beckon to her followers, who answered with yells and howls.

Prim awoke with a cry of terror. The two girls, pale and terrified, stood waiting their doom. They were trapped in a hut and outside was a band of savage blacks. What terrible fate was in store for the trembling victims?

CHAPTER V

The Cave of Wonder

The jungle woman stepped back and was talking excitedly with the other savages. Terry grabbed Prim by the arm. “Let’s get outside,” she said. “There may be some way of escape even yet. Don’t give up!”

The two girls stepped out of the hut to be met by the grinning faces of a dozen or more native women, who rolled their eyes and jabbered shrilly. Prim clutched at Terry.

“They’re cannibals! They'll eat us! Look at their sharp teeth. Let’s run!”

But the woman who had fiercely stared at them in the hut now stepped forward and offered a gift. It was a big package, something wrapped in leaves.

Terry accepted it, trying to force a smile and while she opened the leaves she said in an undertone to Prim, “We’ll have to make them a gift in return. What have we got? Think fast, Prim.”

For answer Prim unfastened the silver necklace with its bright pendant and Terry passed it to the woman. There were grunts of approval, smiles and nods as the other savages pressed close to examine the royal gift. They all seemed satisfied.

Terry had opened the package now and disclosed a big fish baked to a turn and garnished with leaves. “Horrid stuff!” she thought. “How I hate fish! But I’d better pretend to like it!”

Terry broke a bit from the fish, tasted it and tried to look pleased. Then she passed some to Prim and offered to share her gift with the women.

“Me Pedro’s wife. Me Rosa. Come!” said the leader.

The savage repeated the words as if they meant nothing to her. Perhaps Pedro had spent hours teaching her those few phrases.

“Don’t go, Terry,” begged Prim. “They’ll get us to their village, then eat us!”

But Terry laughed. “Why no, Prim, we’ve exchanged gifts. We’re friends, like sisters.”

Prim grumbled as Terry nodded her willingness to go and followed after the chief’s wife who led the way straight toward the jungle. At first the girls could not see an opening in that wall of tangled leaves, but when they reached the trees, Rosa led them into a dark green tunnel and Terry and Prim followed, wondering what was coming next.

They must have walked for half a mile through that passageway cut from the creepers, when the girls saw light ahead and soon emerged on a clearing, among mud huts, a swarm of natives and naked children.

When the girls appeared, a cry went up from the blacks that sent a chill to the heart. It was a sharp, penetrating cry that made shivers run up and down the spine.

But only for a moment were the girls afraid. The natives were friendly, there was no doubt about that. The children stared at them with wonder in their big eyes. The girls lost no time in giving the little ones the few pieces of chocolate they had in the deep pockets of their flying coats.

“I’ll take back everything I ever said, Prim, about you wearing a necklace with flying togs and making me, as well as yourself, carry a supply of chocolate. They have served us in good stead today,” said Terry, her eyes glowing as she watched the children devour the sweets.

Prim was smiling triumphantly at Terry. “Your apology is accepted, my dear! Only don’t let it happen again! And if they are going to spread a feast for us, I wish they’d hurry up, for my stomach is crying for food. Those bananas I ate last night weren’t so very filling after all. And I don’t care whether I ever see another one.”

“No wonder, Prim! I was counting how many you ate and after the twelfth I stopped,” answered her sister with a laugh.

The girls tried by gestures and smiles to indicate their pleasure at everything around them. They complimented Rosa, the chief’s wife, for her fine hut. They admired the babies and by different signs expressed their delight. That they were understood was shown in the shining face of their hostess.

Prim gave a sigh of relief as a young native girl, walking like a princess, was seen approaching with a huge bowl of steaming food. Plaited mats were spread for the guests and food was offered them while the whole village made a circle around them to watch them eat.

Terry, never a big eater, was inclined to be a bit fussy about her food, but today she ate a portion of everything offered, whether it tasted good or not. Prim watched her in surprise and chuckled at the joke on her sister as she pretended to enjoy the fish.

“I don’t care, Prim, go on and make fun of me! I’d rather eat than be eaten!” she retorted. “It’s not too late for them to change their minds, even yet!”

Half an hour went by and Terry and Prim had succeeded in making friends with the shy little children. Suddenly Pedro walked into the clearing. He was scowling angrily. Once more the girls started in fear.

Pedro explained in the few words of English that he knew, how Joe Arnold was very angry and had hit him.

“Joe Arnold much bad man! Bud, much, much bad, too! He kill you, maybe!”

“That’s what I expected!” whispered Terry to her sister.

“No can do!” the black dramatically cried, waving an arm around his little settlement. “No! My people, they watch, they hide you far away! Joe no find!”

Terry explained to the chief what she wanted to do. They must put up some sort of signal so that Allan and Syd, their friends, would see it if they flew over the island.

“If only we had some white cloth,” said Prim. “We could put out one of those signals we talked about once, a big letter T, on the top of a ridge. I’m sure the boys would understand that.”

“They might if we had cloth to do it with, but we haven’t. So that’s out!” answered Terry.

Pedro had risen suddenly. He understood. He called to his wife and spoke to her in their own language. Rosa bobbed into her hut as fast as she could and in a few minutes returned bringing a roll of white goods which she presented to the girls.

At that moment a sharp whistle broke the quiet of the jungle village with a discordant note. Pedro jumped to his feet and the next moment Rosa was shoving the girls before her into the hut. Someone was coming! The whistle was a warning from one of the boys who was guarding the village.

When Joe Arnold strode into the settlement a few minutes later, Rosa was busily plaiting a mat. All the women were at work and scarcely looked up as the man faced Pedro.

“You lazy good-for-nothing! Get back to work! This is my busiest day and you lay off! The men won’t work unless you’re there!”

Pedro knew that this was no time to show fight. “Yes sir! I come by-em-by,” he answered.

“Now!” shouted Joe. Then he turned with a menacing glare at Rosa. “Did those girls sleep here last night?” He shook his fist at the woman.

Rosa jabbered in reply and looked bewildered, so Joe turned to Pedro and repeated the question.

Pedro shook his head.

“Then what’s happened to them? Not that I care much!” stormed Joe as he stared about him.

“We no see ’em!” repeated Pedro.

Joe Arnold went from one hut to another, peering inside. As he neared the chief’s large house, he was met by Rosa’s broad grin. She was sitting in the doorway and her large body completely filled the opening. She refused to get up, pretending not to understand what he wanted.

Suddenly Joe turned and faced Pedro. “Now let me tell you one thing, Pedro. Listen to what I’ve got to say! If you or your people shelter those girls, you’ll be sorry. I’ll clean you out!” And with that threat Joe Arnold strode back through the jungle track.

When he got far enough away, Rosa began to laugh in a low rumble which gradually increased in volume, until it reached a high, full roar. The other women joined in and the clearing was filled with their raucous shouts.

That was their answer to Joe Arnold’s threat.

It was very evident that the girls were being treated as honored guests. Terry found it hard to sample all the food that was brought her, but Prim was in her glory. She liked to eat. She liked strange dishes, and she ate enough for two. Terry had to pretend to be ill in order not to offend her hostess. And then as suddenly she had to pretend to get well again, for the kind-hearted woman insisted that she must give her medicine.—And it was made of fish oil!

That night when Pedro returned from the shore, the news he brought was not good. Joe was planning on taking the girls in the launch over to a small island to the eastward where they would be absolutely alone. There were still wild beasts on that island. It meant certain death.

That night the girls slept in the hut belonging to Pedro. They stretched out on mats and the native women stood guard. Not a breath of air was stirring in that close interior. Terry and Prim felt as if someone were clutching at their throats it was so hard to get a breath. They were not troubled with fears of capture, for Pedro had stationed sentinels beyond the clearing to give warning if anyone approached. But in spite of this the girls slept fitfully. The air was stifling.

At the first glow of dawn Rosa appeared at the door of the hut. She said, “Come!” And there was an excited light in her eyes as she rolled them.

The girls lost no time in obeying her command. A guard of young men went ahead, then came Pedro and his wife, followed by Terry and Prim with two tall and powerful guards. The young women of the tribe came next, and the procession ended with more guards.

“We don’t know where we’re going,” said Prim in a whisper to her sister as they walked along. “But we’re going in style!”

It was a long walk through the jungle passage, a mile perhaps, but it was hard for the girls to tell how far they had come. The damp heat of the tunnel was oppressive. Perspiration streamed from their bodies. Their thick clothes were unbearably hot, although one of the guards carried their heavy coats.

Terry and Prim arrived at the next clearing, pale, hollow-eyed and ready to drop. But the end of their journey was not yet. They had reached the edge of the jungle and now had to climb up a steep ridge to a broad plateau. But the hot air was a relief after the humid atmosphere of the passage through the vines and creepers of the jungle. Suddenly they stopped, looking toward the sky, Joe Arnold might be watching from the air.

Terry and Prim scanned the horizon for signs of an approaching plane. It was hopeless. They both knew that it would never occur to the boys, if they were saved from the storm, to hunt for them to the eastward.

Finally as they reached the ridge, the blacks stopped and prepared to camp.

“What’s the matter with these people?” whispered Prim. “Do they imagine they can hide us on the very top of the ridge? What are they going to do?”

“I haven’t the least idea, Prim, but I’m going to trust Pedro. I believe he is honest and really wants to help us,” answered Terry as she watched the blacks.

Suddenly Pedro dropped to the ground. Terry looked just in time to see the earth swallow him up. She rubbed her eyes and looked again. Pedro had disappeared. Then Terry saw what was going on. Evidently these people had a subterranean hiding place, the opening of which was at the summit of the ridge. The entrance was narrow and Rosa had some difficulty in getting her large body through. She squeezed and struggled, and Pedro pulled from below until she finally slid through. Terry was invited to follow.

What were they up to? How could she explain to them that she must be above ground to watch for her friends?

“Come!” The girls heard Rosa’s voice coming from the cavern. Terry sat down and putting her feet through the opening, found that they rested on a slippery rock. Getting a foothold she put up a hand for Prim. Slipping and sliding down the slope the two girls found themselves in a strange purple glow. When they reached the first level place, Pedro and Rosa were waiting for them.

Terry stood gazing about her. They were in an enormous cave, lined with crystals, and the sunlight which shone through the opening, caught the facets of the crystals and shot out in flashes of color: red, orange, yellow, blue, indigo, violet, and all the thousands of shades between. It was a gorgeous spectacle. The girls were breathless. They had often read of the crystal caves and wished that they could see one.

Finally Terry turned to her sister. “Would you believe it, Prim? For a few seconds I thought something had happened to us, that we had fallen down and been killed.”

“Killed! What are you talking about, Terry? Have you gone crazy from all this excitement?” cried Prim anxiously.

“I thought—well you see I wondered if this was heaven. It’s so beautiful, it might easily be. Even yet I can hardly believe it’s real,” said Terry with a little catch in her voice. “I want to cry!”

“You cry! That’s a joke! Let me see you do it once!” teased Prim. “It’s not often you feel that way, so go ahead. Don’t let me stop you.”

But Terry did not cry. She turned to Pedro and Rosa and thanked them for bringing her to this wonderful cave.

Sea water rose in the cave and made a lake. Finally as their eyes got used to the darkness below they could see a boat. It was built of woven twigs and covered with skin. A small boy who had followed them into the cave, dived into the dark water and swam to the boat. Others followed and the small craft was soon full of little dark figures. With whoops of delight they paddled the boat wildly about the lake.

“Even savage boys have to show off,” said Prim with a laugh.

“Don’t laugh, Prim. They are doing their best to entertain us,” Terry answered as she clapped her hands, which sent the boys into still wilder stunts.

The girls were now in a worse jam than ever. Here they were perfectly safe, they felt sure. But how could they watch for Allan and Syd? How could they signal for help? When Terry explained this to Pedro, he produced the white cloth that Rosa had given them. Terry tore it to the proper size and shape to make an enormous letter T. Much against his wishes Pedro allowed the girls to climb out of the cave and direct the spreading of the cloth on the ground, where it could be seen from the sky.

“It’s only a long chance, Prim, but it’s the only thing I can think of. If we made a smoke signal or anything like that, Joe Arnold would suspect at once,” explained Terry.

“I know, but don’t you think he’ll suspect if he sees this white cloth spread out on the ground?” asked Prim.

Terry expressed her fears to Pedro, who was arranging the work of some men near-by. The big chief assured her that he would attend to that. His people would camp on the hill, then Joe Arnold would think that the cloth had something to do with the work of the tribe.

In less than an hour one or two huts were ready, a crude cooking place had been built and the women were preparing breakfast.

Terry and Prim wanted to stay above ground, but Pedro shook his head vigorously and explained that Joe Arnold was “very much bad,” and was planning to take them away where they would surely be killed.

Terry and Prim slid down the opening and reached the level in safety.

“After all, Prim, we have nothing to complain of. It’s a gorgeous place to be imprisoned. Let’s make the best of it and enjoy it, for we’re not apt to see anything like it again,” comforted Terry as she saw Prim’s frowning face.

“It’s all right here, but I’d rather stay in the open. Besides I’m beginning to like that savage tribe. I’ll say that Pedro is a prince.”

“Oh no, he isn’t,” laughed Terry. “He’s the whole show! He’s the Big Chief. He’s king! And Rosa is a queen, a very big queen!”

The queen herself brought them their breakfast, more strange food, more fish, more bananas. Pedro had already eaten and was on his way with his men to the beach to help Joe and Bud.

The morning seemed long. There was nothing to do but watch the flashes of color in the dome. And even Terry lost some of her enthusiasm at the monotony of the playing light. Finally it got on her nerves.

Suddenly a black face appeared at the opening. A hissing sound came from the thick lips, then the face disappeared.

“What do you make of that?” asked Prim. “Do you suppose that hiss can be translated to mean the same as in our language? Are they hissing us, and why?”

Terry was already making her way up the steep wall of the cave. “I don’t know what it’s all about, but I’m going to find out,” she called back.

As Terry reached the opening, she heard the hum of a motor overhead. Then she ducked back quickly, for there was only one man in the plane. He had banked and circled low, and Terry had seen that mocking face.

It was Joe Arnold!

CHAPTER VI

Trapped!

For a moment Terry withdrew her face from the opening, then like a flash she had scrambled through the hole at the surface and was standing in plain view of the flyer. What’s more, she was sobbing and shaking her fist toward Joe Arnold.

“It’s Skybird! He’s taking our plane!” she cried.

As if mocking her, Skybird flipped its tail gracefully and zoomed into the blue.

As Terry stepped on to the plateau, the women surrounded her, trying to hide her from the man watching them from above. Terry could not be sure that he had seen her, but Prim had no doubt in the matter.

“Now you’ve done it, Terry Mapes!” she cried. “Why don’t you think before you do such a thing? You’re apt to get these people into trouble! Joe said he’d clean them out!”

“Oh, I know, Prim. I’m sorry I did it, but just then I couldn’t help it. I was crazy! I can’t bear to have Skybird used by a smuggler. I’ll feel as if my little plane were dirty after he’s had his hands on her. Prim, what are we going to do?”

But Prim had no suggestions to offer. They were prisoners without question. How long they would have to remain here, she had no idea. They knew only too well what their father and mother were thinking. If Allan and Syd had escaped destruction in the storm, their report would leave no doubt in Dick’s mind, at least, that the girls had been lost in the hurricane. Terry knew that the suspense would mean torture for her parents. How thankful she was that Sally Wyn was with them to comfort them and, with her cheerful ways, keep them hoping that all was well.

If Dick and Alice could only have seen them surrounded by a horde of blacks, they would not have been any more hopeful of their final escape.

Joe Arnold had flown off into the blue with Skybird, and Terry’s heart was sore and bitter with anxiety and anger against her father’s enemy.

If she could have known Joe’s thoughts at that moment, she would have realized that she was in grave danger. Joe Arnold had planned to search for the girls as soon as the important matter of the smuggled silk had been attended to. He guessed that Terry was on her way to Peter Langley’s mine to plead with him to renew the contract and extend the option on the flying field. He had an idea that she was carrying some money.

Joe Arnold was not in a hurry. He had the girls safely on the island. They were his prisoners. He could take his time in getting the papers from them and not run any risk by rushing it. So when the captain of the tramp steamer decided not to leave the harbor that night, Joe and Bud were only too glad to go on board for a good meal, and it was well on toward morning when they reached their huts and prepared to sleep.

In the morning when Joe Arnold went to find the girls, they had disappeared. Pedro seemed truthful when he declared that his people knew nothing about them.

“If we see ’em, we catch ’em for you!” he said.

Pedro’s savage grin assured Joe that he would be only too glad to do it and was eager to earn the reward which Joe offered to any of the tribe who would bring the girls to him.

But it did not take Joe long to suspect that the blacks were protecting the girls. He threatened Pedro with destruction of his village, he swore that no one would be left alive on the island, but the chief merely nodded and promised that he would find the girls and bring them to the camp.

Joe knew that he did not dare to molest the blacks. He could rage and threaten, but he dared not carry out his threats. Once angered, they were ugly and he and Bud might be caught and tortured.

So Joe and Bud decided to wait their chance. Whenever the work at the beach let up for a moment, Bud set out in search of Terry and Prim. He was anxious to curry favor with Joe by finding the girls himself and bringing them into camp.

So as soon as Joe Arnold flew off in Skybird with a load of smuggled silk to be turned into the much needed cash, Bud took this chance to look about the island.

He left Pedro in charge at the beach and began wandering around the jungle, skirting the island. With the Big Chief out of the way he thought he could terrify the other members of the tribe and learn where the girls were hidden.

But Pedro had suspected his plan and, taking a short cut through the jungle, he hurried to the cave and talked to the girls.

“Let him come!” cried Terry. “I’m not afraid of Bud Hyslop. He’s a big braggart, but it’s all a bluff. He’s just a coward!”

“I’d like to get Bud down in this cave and keep him here,” said Prim angrily. “I’d like to keep him here forever.”

“I can’t see how that would help any,” answered Terry. “What we want to do is to get away from the island and down to Peru with this paper. And we’ll not get away by making a prisoner of Bud. That won’t help in the least.”

Pedro was shaking his head. He frowned and his face looked fierce and cruel. The girls felt shudders go through their bodies and realized that the tribe might be really savage if roused to anger.

Suddenly Pedro spoke, and in his halting, broken sentences he expressed his ideas. Bud was on the way to the new village, and when he came, if he made trouble, it would be good to put him down in the cave. Besides they might make him talk so that they would know what Joe Arnold was planning to do.

“And where will we stay?” asked Terry.

“My house!” replied the chief with a wave of his hand toward the hut. “Pedro’s house, your house!” And Rosa led the girls inside the hut.

Pedro covered the opening to the cave with straw mats and giving orders for his followers to guard the girls well, he left to go back to the beach.

But Terry and Prim were far less comfortable here than they had been in the cave. Here there was not a breath of wind, for Pedro’s wife seated herself in the opening and kept out what little air there was.

Finally Terry could stand it no longer. She jumped up and shoved Rosa aside. The big black woman laughed as she watched Terry and Prim mopping the perspiration from their faces.

At that moment one of the half grown native girls ran with a cry of fear to Rosa. She pointed back toward the far side of the ridge, where a man was scrambling up to the settlement.

There was no time to hide away. Terry and Prim stood face to face with Bud Hyslop.

Bud laughed as he had seen Joe Arnold do, a sarcastic, triumphant laugh. He moved toward the girls aggressively, but Rosa was by their side and was shoving them gently but firmly backward.

“You’re to come with me, girls!” exclaimed Bud. “Hurry up and get going! I’ve got you now!”

Rosa pulled them back with a vigorous hand as Bud rushed at them. But his foot slipped, he stumbled and sprawled headlong for a second then went sliding down through the earth. For Rosa had cleverly moved around the straw mats in a straight line from Bud, and when he charged at them, the force of his stride sent him slipping and sliding down the slippery walls of the cave. He did not stop until he had bumped all the way down and splashed into the dark waters below.

“Help, help!” he cried. “You black rascals, get me out of here!”

A young native hauled him out to safety. Bud was half stunned and glad enough to stay in the cave for a little while until he could think what to do. He finally called Terry, but the girl refused to go down into the cave to talk to him.

Hour after hour slipped by. Bud saw none of the brilliant colors of the crystals. He was sore and disgusted, his plans had all gone wrong, and instead of being praised by Joe, he would be despised and blamed and ridiculed.

A strong guard was placed at the opening of the cave and Terry and Prim could enjoy the air. Muggy and oppressive though it was, it was better than the stifling closeness of the hut.

Rosa glowed with triumph, taking all the credit to herself for trapping Bud, and for the rest of the day she was in high spirits, commanding the young blacks as if they were her slaves.

It seemed to Terry and Prim that these people were eating half their time. Huge amounts of fish and fruit were consumed. They started at sunrise and only ended at bedtime.

Terry and Prim slept that night in the chief’s hut, with the faithful Rosa sleeping on a mat before the door. They rose at dawn when the blacks began to stir.

It was still early in the morning when they heard the drone of a motor in the sky and hurried into the hut. For now the real trouble was beginning. Joe Arnold had returned. Skybird soared, banked and circled about the island. Joe headed her low over the plateau, so low that Terry, peering through the matted vines, saw Joe’s face distinctly. His grin of triumph was always unpleasant, now it was threatening as well.

Terry’s face went white with anger as she saw Skybird.

“How dare he use our little plane for his shady business! The crook!” she exclaimed.

If Terry and Prim could have heard the Big Chief when Joe Arnold returned to the beach, they would not have been so trusting. For Pedro told Joe that his men had captured the girls and had them safely in the cave. Bud Hyslop was there now to guard them.

Joe nodded approvingly. Things seemed to be working out just as he planned. His trip to the mainland had been successful and now he was free to fly to South America where he would attend to that little matter of taking up the option on the Dick Mapes Flying Field. But in the meantime he would search the girls and see if they were carrying the money.

“Guess I’ll go on up and take a look at them,” said Joe carelessly. “You might fill up the plane with gasoline. I may need to go out on another trip soon.”

As Joe followed the path through the jungle he thought to himself. “You have to handle these savages rough! If I hadn’t threatened to kill them all, they’d have turned against me. Some day I’ll have a big base here and they’ll all be working for me like slaves.”

But Joe had come by the jungle path and the girls were fully warned of his approach. Rosa went to meet Joe Arnold with a broad grin on her face.

Terry’s heart sank as she watched from the shelter of the hut. She gripped Prim nervously. They clung together in terror. Why had they been so easily fooled? There was Rosa telling Joe that she had the girls safely trapped, waiting for him. The girls shrank back in the hut afraid to come out and face the man who had them in his power. With the whole tribe on Joe’s side, there was little chance of escape. This was the end.

“I’d have sworn they were real friends,” whispered Prim in a frightened voice. “It would be lots better to be on that island with wild beasts than here with these treacherous savages.”

But just then they heard Rosa directing Joe Arnold to the cave. With the few words of English she knew she was telling him that the girls were prisoners in the big cave. “You go down!” she said.

“Sure!” replied Joe with a broad smile. “I’ll kill two birds with one stone. I’ve always wanted to see the inside of one of those big caves. And when I find those girls, I have a few things to say to them.” Joe put his leg down the opening and felt for the rock. Then his other leg found a foothold. As his head disappeared. Bud’s voice called to him.

“Watch out, Joe, they’re tricky! The girls are not here!”

But it was too late. When Joe started to scramble out of the cave, shouting his threats, he was thrust back by a huge black, who held a long knife in his hand. Down he tumbled, bruised and shaken.

At that moment Terry and Prim rushed out of the hut and saw Joe disappear. “Now is our chance to get away, Prim!” cried Terry. “Let’s get to the beach!” Terry grabbed up her flying coat and helmet.

“Hurry, hurry, Terry, he may get out!” cried Prim. Her face was white with the strain.

Terry was saying goodbye to Rosa and the other women of the village. She was trying to express her thanks. It seemed ungrateful to hurry away without a farewell. But Rosa shook her head and shoved Terry ahead of her toward the jungle path, calling back in a shrill voice to the women.

Suddenly Terry started and looked upward. “Listen Prim. It’s a plane!” She had heard the distant hum of an airplane motor and was searching the sky anxiously. Then through the trees she saw the plane driving toward them.

“Who is it, Terry?” asked Prim.

“I wish I knew. Maybe it is a friend of Joe Arnold’s,” replied Terry as she gazed with dread toward the plane that was coming nearer and nearer to the island.

Now the plane was circling above them. The girls watched with anxiety as the pilot put it into a long, fast dive toward the near-by clearing.

CHAPTER VII

Crashed!

The girl flyers watched with thumping hearts as the plane, diving with wide open throttle, headed straight toward the plateau.

Prim gripped her sister’s arm. She felt giddy and faint. A cry escaped her.

Terry turned to her with a frown. “Snap out of it, Prim! This is no time to get hysterical. That plane may be piloted by a friend of Joe Arnold. If it is, we’ll need to do some quick thinking. Don’t lose courage now!”

Prim was gazing toward the plane. “It looks to me as if there were two men. And someone is waving! Do you think it’s a rescue plane?” cried Prim.

Terry did not answer. Every nerve was tense as she watched the plane banking and circling for a landing. She dared not tell Prim that she believed it was Allan and Syd. It would be too great a disappointment, if she were mistaken.

Then suddenly Prim screamed with delight. “Look Terry, look! It’s Syd and Allan! We’re saved! We’re saved!”

Rosa stood beside the girls until she realized that they did not need further help, then as the plane circled low for a landing, she scurried into the hut, calling on the women and children to follow. In a moment the place was deserted. Terry smiled at the idea of Rosa finding protection in those flimsy huts of twigs and leaves.

A few minutes later Allan set down his plane before the native huts. Before the boys could step from the plane, the girls were beside them, shaking their hands and almost crying with relief.

“We thought you were lost in the storm, Allan!” cried Terry.

“And we had almost given you up for lost!” answered Allan, his voice husky.

“How did you find us?” Prim asked excitedly. Her cheeks were flushed, all her fear was gone.

“We recognized Skybird and followed her,” replied Allan, looking around anxiously. “Joe flew her to Honduras and then back here.”

“Don’t I know it!” exclaimed Terry. “What a good thing it was that I didn’t have a chance to stop him. I was angry enough to smash the plane rather than have him use it for smuggling.”

“Let’s be going!” said Syd. “We can tell you how we found you when we’re out of danger. Are you sure these blacks are friendly?”

“I’ll say they are. They’re wonderful people!”

Terry burst out. “They’ve kept us out of Joe’s clutches. He and Bud were trying to put us on an uninhabited island. And Pedro, the Big Chief, hid us away and fooled him. The natives saved our lives!”

“Some day,” said Prim with a laugh, “I’m going to send a whole barrel of presents down for them, beads and candy and brightly colored calico. They’d love it!”

“But when do we go and how?” asked Syd. “I won’t feel safe until we get away from this island. Do you think there is any chance of getting Skybird? Joe won’t give that plane up without a fight.”

“He isn’t going to put up a fight for that plane,” answered Terry. “When we heard you coming, we were just on our way to get her.”

“Joe is down there!” cried Prim triumphantly, pointing at the opening to the cave, near which a huge black was sitting, fingering a knife menacingly. “And as you see, he’s under a strong guard! He and Bud are both prisoners down there.”

“Prisoners! Where?” asked Syd.

“It’s the most wonderful prison in the world! It’s a crystal cave! The roof is of sparkling emeralds, rubies and sapphires. It’s beautiful!” Terry explained with sparkling eyes.

“Yes, you ought to see it, boys!” interrupted Prim.

“We’ll save that for the next trip. Much as I’d like to see a crystal cave, I think my pleasure would be all spoiled if I had to share the view with Joe Arnold,” answered Allan.

At that moment Pedro came running up the trail. He had seen another plane arriving and feared that Joe and Bud might be rescued by some friends. His white teeth showed in a broad smile when he saw the girls happy.

“My plane? Is it ready?” asked Terry.

“All ready!” replied the black.

Pedro started to lead them back to the harbor, but Rosa stood in his way, frowning and talking in a high pitched voice. The chief explained to the young people that the tribe wished to give the flyers a farewell feast.

“Guess we’ll have to wait long enough to eat something,” said Terry under her breath to Allan.

“But we really ought to be going when luck is with us. You can’t tell what may happen!”

“It’s impossible, boys. It’s the only way we have to repay these people for their kindness to us,” Terry begged.

“That’s a brand new idea, repaying people by eating some more of their food. I don’t know as I’d want that kind of pay for a debt.”

“You would if you were in the place of these people. It’s the greatest honor we can show them.”

After assuring Allan and Syd that Joe Arnold and Bud Hyslop were well guarded in the cave, Terry led the way to the fibre mats before the huts where the meal was about to be served.

“How did they guess that we hadn’t had a thing to eat today?” asked Syd. “We were too busy watching Skybird. We didn’t dare leave the field for fear Joe Arnold would take off and we’d lose him.”

“I’m glad you’re hungry,” said Terry in a whisper to the boys. “I wish I were, then I might be able to eat their fish. And unless you eat a lot, Rosa is offended.” As the bowl was brought in, strange spicy odors filled the air. They had several courses. The feast began with fish, continued with fish and ended with fish.

Terry bravely faced the ordeal, trying to smile and enthuse over each dish as it was brought. But it was hard work. However, the boys made up for her lack of appetite. They declared that they had never tasted anything so good and when they accepted a second helping, Rosa’s face was beaming with happiness.

Allan was thoughtful for a time, then his face brightened. He had been racking his brains to think of some gift to present to Pedro. At last he had it. From his pocket he took a wrist watch. Allan usually carried an extra watch.

Terry saw the idea and smiled. “He’ll love it, Allan! But make a lot of fuss when you present it,” she whispered. “They like that even better than the gift.”

The four friends rose and bowed low before Pedro. Then Allan stepped forward and fastened the watch on the wrist of the black.

Pedro did not know what to say. He tried to speak but his few words of English were forgotten in his excitement. Like a king, he strode among his people with extended hand to show them the honor that had been given him. Rosa beamed her pleasure. It was a great day on the island.

Allan and Syd were restless. “I think we’d better go!” said Allan suddenly. “I won’t be happy until I get you girls a thousand miles away from Joe Arnold and Bud Hyslop.”

“O.K.,” replied Terry. “Come Prim,” she said, and her sister followed as Terry went among the natives and bade them goodbye.

Allan and Syd started their plane and flew above the forest toward the beach, while the girls hurried through the jungle by a short cut that Pedro took and Rosa followed as fast as she could.

The boys were putting their plane down on the smooth water beside Skybird when the girls arrived. Pedro leaped into the launch and beckoned the girls to follow.

Suddenly they heard wild, piercing cries coming from the direction of the jungle, savage cries that sounded more like the night call of some jungle beast.

“Hurry!” exclaimed Pedro, looking back. “It’s Joe. He escape!”

Joe and Bud were racing madly toward the beach. In a moment the reason for their panic was seen. Behind the two men came a stream of howling blacks.

“Will Joe hurt you, after we are gone?” asked Terry anxiously.

“Me no afraid!” Pedro answered. “My people, they fight him!”

Bud made for a boat, but one of the natives came up and shoved him aside violently. Joe was struggling with a horde of blacks, and all he could do was to shout furiously to Terry. But Skybird was free from her moorings and the girl started the engine ready for the take-off. She could not hear what Joe was saying, but it was abusive and threatening.

Sending a spurt of water before her, Skybird taxied in a wide sweep to head into the wind. Pedro stood up in his boat and waved a big black hand. There were shouts of farewell from the shore, mingled with threats from Bud and Joe.

As the plane soared over the island, Prim said through the earphones, “You may call those people savages if you want to, but I’ll count them among my very best friends. What’s more, I’m coming back some day to see them.”

Allan took the lead, straight westward. The deep blue water spread beneath them to the horizon. There was hardly a ripple on the mirror-like surface of the sea. The sky was clear and like birds the two planes soared alone in the great blue dome.

Only occasionally Terry looked back in the direction of the island to be sure that Joe Arnold was not in pursuit. She had confidence in Pedro.

It was still early in the day. Terry and Allan had consulted their maps and decided to head for Tela on the Gulf of Honduras. If possible they wanted to get over to the Pacific side by night. There they would feel safe.

Flying in a northwesterly course, they left the high rocky coast of Honduras that lay exposed to the Caribbean storms, and made a landing at Tela. But they did not stay long, a heavy mist had come in from the sea. Within an hour they had made a check-up on their aircraft, refueled and were taking off for Salvador on the Pacific where fair weather was reported.

A low-lying cloud made Terry nose her plane up to a height of ten thousand feet. There was a brilliant sky and sunlight overhead. Below it looked as if they were still flying over the ocean. The broad sheet of fog spread beneath them like a blanket. But when they neared the Pacific late that afternoon, the mist began to thin and they could see the ranch houses with their cultivated fields. Leaving the cloud behind, they flew over Salvador. From that height they could see far north to the towering Guatemalan plateau, with here and there a cone-shaped volcanic peak. Plumes of blue smoke shot from the craters.

Prim gave an exclamation of astonishment, then was still. Both girls felt the overpowering majesty of the outlook over that vast panorama. Soon they saw the red and green roofs of Salvador City and a lofty Gothic spire. Terry circled over the town and came down on the flying field.

Here they intended to spend the night and have their planes thoroughly overhauled for the trip down the Pacific. The air was clear and dry, perfect flying weather.

But Terry was restless. While she enjoyed seeing the foreign city, she was fearful that Joe Arnold might still be pursuing them. Now he had a still greater reason for finding them. In the plane Terry had discovered a large legal envelope with several important looking papers marked “Confidential.” Looking at them hurriedly, Terry gasped. Among them was the will of Colonel Roger Fairfax, a document that disposed of millions of dollars worth of property.

At the hotel when she showed them to the boys they agreed that they were extremely valuable. Yet they saw that the possession of these papers would add to the peril of the girls. Joe Arnold would not rest easy until he had caught up with Skybird and recovered the documents which he had stolen, no doubt, and expected to sell for a huge sum.

Terry did not sleep well. She wanted morning to come so that she could be on her way, and long before daybreak she was up and ready to go. After a hasty breakfast, the four flyers took off and were under way by the time the sun was rising.

It was a long day. The flight down the Nicaraguan coast was jumpy, for the cool air from the high mountains poured down to meet the warm air from the plains. They passed near to some of the volcanoes and once they could see into the crater with its boiling lava and clouds of steam and smoke.

“We’ve been lucky!” said Prim through the earphones. “From now on it’s clear sailing!”

“Touch wood, Prim! We’re not there yet,” answered Terry.

But Prim had not touched wood quick enough. A few hours later when they stepped from their plane on the field in Panama, they noticed at once that there was trouble. Men were running about excitedly, looking into the sky and the ambulance was being started ready for an emergency. In the sky a plane was out of control and diving wildly.

“Oh Prim!” cried Terry. “It’s Allan! He’s falling!”

The plane above had gone into a tailspin and the girls knew that Allan was not the kind to show off his skill or attempt a stunt over a strange flying field.

Prim clung to her sister with cries of fright but Terry’s face was grim. Her lips moved with a prayer, but no words came.

Allan’s plane was falling! Nothing could save it now. It was too near the ground to be righted and landed safely.

But the next minute the plane straightened out. By some miracle of luck Allan had it under control again, but it was too late. The plane landed on one wheel and with a bound it turned clear over. Even before it touched the ground, the ambulance was speeding across the field.

Prim ran screaming toward the plane but Terry stood as if turned to stone.

Allan and Syd had crashed! Their bodies must be crushed and bleeding under that crumpled wreck. Allan and Syd were dead! Terry saw no hope.

But strong hands had dragged Syd from the rear cockpit. He was dazed from the shock of landing but Terry saw that he was alive.

Frantically she ran toward the plane. Where was Allan?

Allan, strangely white, was taken from the wreck and placed in the ambulance. His limp form was covered with blood. Next minute the clanging ambulance was racing the injured boy to the hospital. Syd was given first aid on the field and was able to ride with the girls to the hospital in the automobile of the field manager. The boy was shaken up, bruised and sick from the shock, but he had no serious injuries. The girls watched him anxiously as he trembled and twitched, but the doctor at the hospital assured them that it was entirely nerves and after a night’s rest he would be himself again.

But with Allan it was far more dangerous. Behind the closed doors of the operating room, strange white-clad figures were working over Allan. Terry caught glimpses of hurrying nurses, but dared not speak to any of them. A moment’s delay in carrying out an order might be a risk to Allan’s life.

Suddenly Syd seemed to come out of his stupor. He tried to get up, looked wildly around and cried: “Where’s Allan? Tell me, is Allan dead?”

“No, Syd, lie down and keep quiet. Allan is alive! He has a fighting chance. That’s all we know now.”

An hour went by and dragged slowly into two hours before they brought Allan from that operating room. His long body was motionless under the sheet. Terry had slipped into the corridor and was watching. She held her breath with dread. Would they bring that still form toward a room, or was it all over? Was Allan dead? Would they take him away?

No one had time to answer her questions if she could have spoken. But her heart leaped with hope as she saw them turning into the room next to Syd. Allan was alive!

Then came the thought, as it had come when her father was injured: “Would this happy, care-free boy be left a cripple?” She thought of her father, spending his best years in a wheel chair and her eyes filled with tears. It was agony to think of that alert and active Allan doomed to the same fate. If only someone could relieve this terrible suspense!

CHAPTER VIII

Jump

Terry turned to the doctor who had just come in. She tried to speak, but words would not come.

The doctor approached with a smile of sympathy. “I guess this fellow was born under a lucky star,” he said. “He’s pretty well shaken up, but there is nothing serious that we can find. A few broken bones! The shock of a fall like that is always bad. He’ll be flying again in a few months!”

Terry did not wait to ask questions. She flew to Syd and Prim to tell them the good news.

Allan was alive! He would fly again!

Terry set out for South America two days later with a heart full of gratitude that Allan was not seriously hurt. The morning after the accident he was able to talk to her and while he looked worried to think of the girls flying alone into the dangers of a strange country, he did not try to keep them from going on.

Terry was getting nervous. The day set for taking up the option was almost there. The work she set out to do must be done quickly.

From his bed in the hospital Allan watched the plane soaring away from the field. It remained a tiny speck in the sky for a long time in that clear air.

“I feel as if we should have stayed to look after Allan,” said Prim through the earphones. “Do you think Syd can do everything that’s needed?”

“Allan is in a good hospital,” replied Terry. “He’s well cared for and there’s nothing we can do right now. We’ll get this job through as quickly as we can and get back.”

Following the airway down the coast, Terry had no difficulty in reaching the town of Trujillo in the northern part of Peru, at which point she was to turn inland to Majora, a settlement of adobe houses and stores, the center of supply for a number of mines in the mountains.

Over an early breakfast at Trujillo, their spirits rose once more. The trip inland was not far and they should reach the foothills in an hour.

“South America is different from what I expected,” remarked Terry, as she drank her breakfast coffee. “I thought that most of this country was jungles and tropical vegetation. Did you see that strip of brown sand, along the coast? It’s like a desert.”

“Which shows you didn’t study your geography very well or you’d have remembered that all along the coast, especially from here down, there’s a strip of desert, and in places it never has been known to rain,” replied Prim. “I always remember that, for it was one place I never had any desire to go. But here I am!”

“We’ll just give it a good look and fly high! I don’t like desert country either. But we’ll soon get to the foothills.”

“Let’s hurry, Terry! I’m anxious to get to the mine. I wonder what Peter Langley and his wife will be like? I hope they won’t turn out to be friends of Joe Arnold.” Prim picked up her belongings and hastened toward the door of the restaurant.

A few moments brought them to the flying field, where their plane had been refueled and stood ready for the take-off. There was no wind and Terry taxied across the field to get plenty of speed for the rise. As usual Prim had insisted on the parachutes. The harness always annoyed Terry, but she did not make any objection. Anything that would make Prim feel satisfied was worth doing.

The rising ground beneath them told that they were getting into the foothills. They saw the jagged peaks far ahead. Terry was glad that she would not have to cross the Andes on this trip. She had had enough excitement for a while; that could wait for another flight.

Seeing a small settlement ahead, Terry recognized it by the description given her of Majora. She flew straight toward the town, circled and came down on a wide, smooth field. Although it was not intended as a flying field, Terry had seen worse places to alight, and brought Skybird to a neat three-point landing.

But here the girls met disappointment. Ed Jenkins, an American storekeeper in the settlement, told them that it would be impossible to land a plane in the mountains near Peter Langley’s mine.

“There isn’t a square foot of level space anywhere in these hills. That pair of fools who went up there in a plane this morning will meet sudden death. They’re bound to!” exclaimed Jenkins.

“Two men went up there in a plane this morning!” cried Terry excitedly. “Who were they?”

“I can’t say, Miss,” replied Jenkins. “One had red hair and the other's eyes were funny! A queer looking pair of crooks!” Ed Jenkins was fumbling in his pocket. “Here’s a message. I guess it must be for you. The man with the squint said to give it to two girls in a plane. I reckon that’s you!”

Terry ripped open the envelope and read these words scrawled on a scrap of paper: “He laughs best who laughs last!”

“Come on. Prim, let’s go!” Terry’s face flushed, then set in determination. “That’s a challenge! If Joe Arnold thinks I’m through, he’s mistaken!”

But Ed Jenkins was pointing to the mountain, where a few stone huts were visible. “That’s Peter Langley’s mine up there! You can see for yourself there’s no place to land among those peaks!”

But Terry had already started the engine. The propeller was spinning. And with a wave of her hand to the storekeeper, she sent her plane across the field and into the air. Circling for altitude, she pointed straight toward Peter Langley’s mine.

“I believe that man is right,” said Prim a few minutes later, as the hills became more rugged and menacing with their sharp peaks.

Terry flew slowly over the hills, watching for a spot to put her plane down. If Joe Arnold and Bud Hyslop could find a place, surely she could. She brought her plane as low as she dared above the mountains but there was no sign of level ground, and soon she saw little figures running about and waving at her excitedly.

“They’re warning us not to try a landing,” Prim called to her sister. “i’m afraid it’s no use.”

“Then I’ll have to use the parachute! Come over here and take the controls. I’ll have to jump,” cried Terry.

“Don’t, Terry. It’s a terrible chance to take!” pleaded Prim.

“Nonsense! I’ve made lots of parachute jumps!” Terry snapped impatiently. “Don’t waste time! We have less than ten minutes to get there. Peter Langley can’t close a deal with Joe Arnold until twelve o’clock. Our contract holds until then.”

Prim’s face was white as she climbed into the pilot’s seat, protesting nervously. “Don’t jump, Terry! Don't take such a big chance!”

But Terry was studying the ground below her and she answered, “I’ll jump when we are directly over the mine. You take the plane down to Jenkins' store and wait for me there. I’ll be down after a while. Bye!”

Then at sight of Prim’s tragic face, she laughed and began crawling out on the wing. Terry watched the ground beneath her, then with a catch in her breath, stepped out into space.

No matter how many times Terry jumped, she never could get used to that long drop. Her mind was clear, every sense alert to what she had to do.

In a few seconds she pulled the rip cord but there was no response from the parachute.

Had something gone wrong? Terry was falling with terrific speed toward those jagged rocks. “This is the end,” she thought. But suddenly she came up with a tremendous jerk as the parachute opened above her head and she began sailing gently downward. Working with the shrouds, the girl steered the parachute toward a safe landing.

At the sight of a figure hurtling through the air, Mary Langley had screamed, “Oh Peter, Peter! A man has fallen from the plane! Help! Help!”

Horror-struck, Peter Langley watched the falling figure, then gave a lusty cheer as the white parachute opened, the little figure in the sky was righted and came sailing down gracefully.

“I was hoping she’d break her neck!” muttered Joe to Bud Hyslop. “Just as I was getting the did man interested, she had to spoil everything! But I’m not through! He’s got to take my word against hers!”

“Sure!” answered Bud. “Terry Mapes is no good at a business deal. She’ll not convince Peter Langley!”

While Bud and Joe looked on sullenly, Terry landed on the mountain at some distance from the astonished old couple, who hurried along the trail to reach her.

“He’s a brave man whoever he is,” said Mary Langley. “Jumping from the sky like that! It scares me to think of it!”

“I wonder why he’s coming here?” asked Peter Langley.

Terry was just picking herself up and rubbing a bruise on her arm, as the old couple scrambled up the rocky ledge.

“Bless me, if it isn’t a girl, and a pretty one! Did you have to jump out of that plane?”

“Yes,” replied Terry with a laugh. “I had to jump! I had to get here before twelve o’clock and that was the only way I could do it. I’m Terry Mapes and I’ve come to take up the option on the flying field.”

Peter Langley stared at the girl in astonishment. “You did that? You brave, brave girl!”

Mary Langley was brushing Terry off and helping her to get out of her parachute harness. “Come along to the house,” she said. “I’ll make you a cup of good strong coffee to brace you up, though goodness knows it would take more than that to bring me to, if I’d jumped from a plane! What are girls coming to! When I was young I’d never have dreamed that girls could do a thing like that!”

“Times are different!” agreed Peter with a shake of his tousled white head. “And you made it without an accident, which is more than my other two visitors did.”

“Were they hurt?” asked Terry.

“Not much! They landed their plane somewhere down the slope and broke the propeller. Joe Arnold has a sprained ankle and a bruised shoulder,” replied Peter. “He isn’t feeling very good.”

Terry looked at the old man anxiously. “You haven’t signed any papers, have you, Mr. Langley?” She looked at her watch. “It’s just one minute before twelve. I still have time to take up that option. Here’s your check!”

Peter shouted with laughter. “What a girl!” he exclaimed. “No, I haven’t signed any of his papers!”

“And what’s more you won't sign any of them!” Mary Langley cried. “I don’t like the looks of those two men!”

“No more do I!” agreed Peter.

As they reached the ledge of rock where their cabin stood, Peter was confronted by Bud Hyslop. “Don’t have anything to do with that girl!” he stormed. “She’s been in more crooked deals than you can count. You’ll be making a great mistake.”

Peter gave a quiet laugh that was more provoking than if he had stormed at the men and accused them of fraud. He turned to Terry. “Come right in, Miss Terry,” he said with a deep old-fashioned bow, “I’ll just sign that paper and close the deal!”

Joe Arnold bit his lips in rage. His face was deathly white. Terry had never seen the man so angry before. Joe had staked everything on this trip to get the flying field, and he had lost. Even his plane was a wreck and he was miles from a railroad.

Joe Arnold’s brain was working hard on a new plot. How could he get Skybird? And how could he get those stolen papers back? Perhaps they were still in the plane, maybe the girls had overlooked them! But that was not likely. Terry and Prim were too clever to miss a chance like that!

Joe studied the sky. Far down in the valley he could see the plane, with Prim at the controls, just making the landing by the store. Terry noted the look of hatred and villainous hope and her eyes followed his.

Suddenly she understood. Already Joe was talking to Bud. They were preparing to leave.

“Stop them, somehow!” said Terry to Peter Langley. “He’s going to try to reach Majora and get our plane. My sister Prim is down there! Don’t let them go!”

Peter stood in the path in front of Joe Arnold. “You have a few things to clear up before you leave, Mr. Arnold,” said the old man. “I’ll not let you go until you explain some of the stories you’ve told me about Dick Mapes and his family.”

“Get back!” shouted Joe Arnold furiously. “Out of my way!” His voice cracked in rage. Suddenly his fist shot out. Bud landed a second blow and Peter Langley reeled and staggered back, shouting for help.

There was a sound of running feet and the next moment a gang of miners rushed at the two men and tied their hands. After their struggles had quieted the pair were thrown into a corner and ordered to behave or take the consequences.

Terry looked anxiously toward the valley where she could see a small figure on horseback. It looked like Prim coming to her rescue.

“What shall we do with these crooks?” asked Peter Langley.

“Lock them up until Prim and I have time to get away,” Terry begged.

At Langley’s command, the miners dragged the two rascals to a stone shed. The heavy door had a strong lock.

“There they’ll stay until I’m sure you girls are safely home,” said Langley. “I’ve a notion to have them jailed!”

When Prim arrived in camp she was greeted as if she belonged to the family. She and Mary Langley were soon like old friends. They had many interests in common. And while Prim was being shown over the house, Terry and Peter Langley were exchanging stories of their adventures.

“Wait till I show you this!” said Peter going to a shelf in the corner. “Here’s a map I made on one of my trips. I went through the Land of the Incas with a native guide. We were looking for a lost temple. It is said that there’s a sacred emerald in the altar. Now the temple is lost, no one knows where it is. If I were young and had an airplane, I’d go and find that temple. Besides there’s treasure there.”

“I’d like to find it myself,” said Terry eagerly.

“Why don’t you? It’s a wonderful country down there. You’d see new sights and have new adventures and maybe you’d find the treasure.”

Terry’s eyes were dreamy as she studied the map. “Would you be game to go with me?” asked the girl. “This map is like a challenge. I'm going to do it!”

“Going to do what?” asked Prim.

“First I’m going to Panama and after that we’ll go on a treasure hunt in the Land of the Incas.”

Mrs. Langley laughed. “Peter has been showing her his map! I do believe he’d start out himself to find that treasure, if I’d let him.”

“Maybe I will,” replied Peter. “Terry says she’ll take me along. And I’ll trust myself to her any time. After seeing her jump from a plane I know she’ll get what she goes for, so I’ve given her my map.”

Terry rose to go. “We’ve got to get started! I wish I had more time to look around, but some day I’m coming back.”

Mrs. Langley threw both arms around the girl. “Promise me that you will. And next time don’t be in such a hurry to arrive. Come up the mountain on horseback. I was scared to death, almost, when I saw you falling.”

Peter saddled his own horse for Terry with instructions to leave it with Ed Jenkins, who would see that it got back. The girls waved at the old couple as long as they could see them and when they reached the store in Majora, Prim ran to the plane and got the binoculars. Looking back to the mine she saw the two old figures still standing on the rocky ledge and waving their hands.

As they took off. Prim suggested that Terry fly once more over the mountain, but Terry shook her head.

“Not this time, Prim. We must get back to Panama. But if Allan is all right and doesn’t need us, I would like to take that trip to Peru on a treasure hunt,” replied Terry.

From Trujillo, where they stopped for fuel, she sent a cable to her father and also one to Allan and Syd, who would be anxiously awaiting word.

Then as they headed up the Pacific it seemed to Terry that Skybird knew that she was facing homeward, the engine hummed and the country unrolled beneath them, like a great moving picture.

They found Allan recovering rapidly, although it would be many weeks before he could be moved. Terry and Prim were making their plans for the trip to Peru.

But Allan seemed troubled, and after much questioning Terry learned the cause of his worry. Some one was needed to follow up on that business deal. Dick could not attend to it all from his wheelchair and the other men about the field were not dependable.

“So you want me to go back?” asked Terry. “Is that it?”

“No, I don’t want you to go back! I want you here!” replied the boy.

Terry was quiet for a long time, she was thinking hard. Again she stood where duty called. She had to choose between her own pleasure and her duty to those she loved. There was a fierce struggle in the girl’s soul. Why did she always have to give up her own desires?

Suddenly she rose and held out her hand to Allan. “I’m starting home in the morning,” she said simply.

Allan looked troubled. “But Terry, your trip to the Land of the Incas! Your hunt for treasure!”

“Oh, that's nothing. That can wait!” she said with a laugh.

Even Allan did not realize how great had been that inward fight. Terry wanted to get away from all the problems of the flying field, the conflict and jealousy of Joe Arnold and Bud Hyslop. She wanted a month of freedom, just flying around and enjoying herself without any thought of duty or business details. She wanted to fly for her own pleasure.

The next morning she was on her way north. She circled her plane high up into the clear air. Ten thousand feet above the earth she could forget the problems of life. She could dream undisturbed for Prim always knew when to keep quiet.

But little did Terry dream that in the Land of the Incas, the Girl Flyers would endure many hardships, face grave dangers and many times would escape with their lives only by a hair’s breadth.

THE END

*** END OF THIS PROJECT GUTENBERG EBOOK ON ADVENTURE ISLAND ***