The Ghost of Mystery Airport
Date: 2014-08-22T00:00:00+00:00
Keywords: Detective and mystery stories; Ghost stories; Air pilots -- Juvenile fiction; Airplanes -- Piloting -- Juvenile fiction; Aeronautics -- Juvenile fiction

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Title: The Ghost of Mystery Airport

Author: Van Powell

Release date: August 22, 2014 [eBook #46656]

Language: English

Credits: E-text prepared by Roger Frank and Sue Clark

*** START OF THE PROJECT GUTENBERG EBOOK THE GHOST OF MYSTERY AIRPORT ***

E-text prepared by Roger Frank and Sue Clark

Transfixed, rooted to his tracks, Chick gasping, stared.

The Ghost of Mystery Airport

By VAN POWELL

THE SAALFIELD PUBLISHING COMPANY

Akron, Ohio        New York

Copyright MCMXXXII
THE SAALFIELD PUBLISHING COMPANY
The Ghost of Mystery Airport
Made in the United States of America

THE GHOST OF MYSTERY AIRPORT

CHAPTER I

A PILOT WHO LIKED SPOOKS

“Scared?”

“Not a bit!”

Garry Duncan, just behind the pilot who had asked the question, answered it in his usual, cool manner.

Behind him in the three-place open cockpit biplane, his thirteen-year-old chum displayed none of his calm.

“I’m scared!” Chick cried as the pilot cut down his throttle. Chick raised his voice to a tremulous shout, “Scott—turn back.”

The man at the controls laughed.

“Don’t be a baby!” he counseled. “Just because you see a cloud begin to look shimmery—the first sign of the ghost, according to all the pilots who have seen it—don’t lose your nerve.”

“But—this ghost hunt might be dangerous,” Chick began to plead. “C-can’t you—Scott, can’t you t-turn and go out on the bay?”

“No. I cut the gun too much and the engine died. We have to glide in, dead-stick, to the best landing we can.” There was no regret in the pilot’s voice. He proposed to carry through his purposes.

“But—” Chick was hopeful as he offered an argument, “in the dark here, the swamp is dangerous—you might miss water and you’d get the wings torn in the grass.” He added quickly, “or you may get our pontoons bogged—” As the airport searchlight made a cloud glow he cried, “Yes—bogged down in the ooze.” He expected to see the ship bank, indicating that his hint was being acted on.

Instead the ship’s nose went down. Scott, with a little laugh of amusement at Chickering Brown’s fears, found additional terrors for the youngest of the pair with them.

“Yes,” he agreed, “and then the spectre that always appears in the clouds might fly down on us and say ‘boo!’”

He turned, as they glided, high above the swamp.

“How about it, Garry? Wouldn’t that be awful?” Garfield Duncan, fifteen-year-old student-pilot and assistant to an airport manager’s nephew, answered seriously.

“Terrible!” he agreed, “but it would be Chick’s own fault. He was so interested in the mystery that he vowed he wouldn’t be scared.”

“Well!” Chick hoped for one means of allaying his fears—light. “Why don’t you throw over a landing flare, Scott! It’s pitchy-black down in the marsh.”

“Scott will get us down, even without power.” Garry voiced his confidence in the test pilot who knew the channels and open water spaces like a book. “Great Scott,” as they had nicknamed him, made many test flights for the American branch of a foreign seaplane manufacturer; of late, since an airport had been inaugurated in connection with the seaplane “base,” Scott had flown over the marsh at night, conducting tests of new lighting equipment, spotlight, searchlight and beacon.

“If you’re afraid,” he added, “try whistling, Chick, my boy! I’ve heard that ghosts won’t come around if you whistle.”

Usually Garry did not tease his younger chum; but Chick had been so confident of his own bravery, had so insistently begged to be one of the “spook trappers,” that Chick’s terror in the face of darkness—and of nothing worse, so far—prompted him to be a little sarcastic.

“It’s all very well to sneer,” said Chick. “I wasn’t scared, back in the design room—but here—” he stopped. They had been filing blue-prints in the plant of an Italian aircraft building company when Scott, its test pilot, had come quietly into the blue-print room where Garry made the multitudes of blue-prints from pen drawings for the many detailed parts of the company’s product.

The secrecy of his entrance had fascinated Garry’s more youthful companion, who filed the blue-prints and sketches. Chick had caught a hint of something secretive about Scott; it had fired his ready imagination and he had been so eager to hover close that Scott, after a moment of hesitation, had included him in the proposal he had made.

“You both realize how serious that Sky Spook scare has come to be,” he had whispered. “I wasn’t going to say anything to Chick, because he’s pretty young—” at once Chick had denied the insinuation, “—all right, Chick,” Scott had continued. “Just the same, I wasn’t going to include you—but it may help, at that—if you are ‘game’ and not scarey.”

Assured of Chick’s absolute bravery and perfect gameness the test pilot had suggested that he wanted to “get to the bottom—or top—of the spook business.”

“Ever since the first pilot cracked up,” he had said, “and explained that he thought he saw a spooky-looking crate flying straight at him out of a cloud, I’ve thought he was trying to ‘cover up’ his own carelessness with that story. The next one to see ‘it’ must have caught the scare and had an overdose of imaginittis. But it has gotten into the newspapers and they call the new airport ‘Mystery Airport.’ It’s ruining business for Don McLeod’s uncle, and I’d like to help him out by proving that there isn’t any ghost ship flying in and out of the clouds to make a pass at every pilot whose firm gives the new airport its business.”

Garry had agreed with Scott’s theory that some hidden enemy was trying to ruin the airport’s business, and hamper its growth. Readily he had consented to help Scott with his simple plan, which required that with Scott the two youths would fly, that night, inviting the appearance of the ghostly, or human apparition, at which time Scott felt confident that he could run down the culprit and end the scare before it further harmed the morale of the flying force or resulted in the loss of contracts for air line hangar space and landing and take-off fees.

The eagerness with which Chick had seconded the plan, his pleading to be included in the airplane’s passengers as an observer and signalman, his stout declarations of his complete fearlessness, had suddenly become empty boasts when the three-place ship had reached the vicinity of the swamps adjacent to the airport but not yet drained and prepared for filling in. Eventually the greater part of the swamps would be changed into good ground. Engineers were already preparing to drain away the salt tides flowing in from Long Island Sound and Little Neck Bay. Unless the unexplained mystery of the spectral sky denizen could be settled, it seemed unlikely that the swamp land need ever be reclaimed for airport expansion.

Scott, for years the hangar supervisor and chief test pilot for the airplane construction plant and seaplane base which had existed before the airport project in combination with them had been started, was very anxious, it seemed, to end the ghost scare.

With his two youthful aides, confident Garry and shivering Chick, he made a good descent to the surface of a wide sheet of enclosed, shallow water, let the amphibian craft, which could make either earth or water landings, run out of momentum, and then sat back, loosening his helmet chin straps.

“Here’s the full plan,” he turned around in the cockpit in the dark, salty-smelling marsh, silent except for the plash of a leaping fish or the cry of a gull seeking a belated dinner, “I didn’t want to be seen talking too long at the plant. You never know who ‘might be’—you know!”

“I understand,” admitted Garry. “Let’s hear it all.”

“I went to Don as soon as I left you—and he’s managed to get Mr. McLeod to let him go aloft in the Dart.” He referred to a light, fast two-seater, the personal property of the airport manager, which his seventeen-year-old nephew had secured for the evening. “Now, Don is as good an amateur pilot as you’ll find; but he lacks stunting experience. He will come here, set down, and then I’ll take the Dart and keep it warmed up and ready, while Don, with you two for observers, will go up and cruise around—and invite Mr. Ghost to come at you!”

Chick shivered and muttered under his breath. “If Mr. Spectre shows up, you signal to me——”

“I know.” Garry recalled arrangements used in other night communications, during night tests. “If the spook appears in the clouds, we set off a red flare. If ‘it’ takes off from the ground, we give you a green Verey signal and you’ll be able to catch anything slower than greased lightning in that Dart—and drive down the ghost and prove it’s only some human person, after all.”

“Well, that’s what I hope to do.”

“Sup—supposing it isn’t a h-human being?”

“That would tickle me to pieces, Chick, old top,” laughed the pilot. “I’d sort of like to have it turn out that way. Why? Because I never shook hands with a ghost, and it ought to be a right nice experience.”

“He—it would scare you out of your togs!” scoffed Chick.

“Oh, no!” Scott assured him. “Spectres, if they really do exist, can’t hurt you. It’s only your fear that can do you any harm. Now, I like spooks!—-”

“Yes?” Garry pointed up toward the July night sky. “Well, there’s one! Go up and get acquainted. We’ll wait here!”

He had meant to joke, to terrify Chick; but he became silent and a trifle awed.

There was—something!—black against a luminous Summer cloud!

CHAPTER II

THE AIRPLANE GUARD

Shuddering, terrified, Chick clung to Garry’s steady arm as he gazed upward.

One of the clustered clouds seemed to be picked out from the others by a phosphorescent glow: it was luminous but not fiery; whitish in tint rather than ruddy.

Out of it came a silent, gliding, dark shape—an airplane!

For a brief interval Garry felt his own blood chilling. That spectral shape was very much like the mental pictures he had visualized after he had listened to the story of the pilot who had cracked up because of a similar apparition.

Then the real explanation flashed into his mind.

He gave a relieved laugh.

“Hooray!” he cried in the still, dark cockpit seat, “the ghost of the skies is explained.”

“So it is!” agreed Scott, the pilot.

“Don’t—” began Chick; but his own words died as he saw that they were not facing any supernatural appearance.

The light died out of the cloud as the airplane, a lightly-built and fast-moving craft, came steadily lower, closer. It was real!

“It’s Don!” said Garry, reassuringly.

“Yes, it is Don, all right,” agreed Chick, his own fears gone.

Garry watched the light ship make its approach, silent but genuine and then gave Chick a brief lecture.

“I’m glad you came, after all—aren’t you?” he remarked. “Now you can see for yourself that every scare that seems to be started by spooks is all in the way you judge what you see.”

“It’s that way just this time,” admitted Chick grudgingly. “The darkness, and the swamp, and all the talk made me think I saw a ghost ship coming out of a lighted cloud.”

“Certainly,” agreed Garry, “and you thought that, because you heard somebody else say that was how the ghost appeared. But it turns out to be Don in the Dart, coming down out of the sky just when the control man at the airport had his searchlight switched on and turned it past the clouds.”

“For my part,” Scott informed the two chums, “I don’t think the first crack-up happened because the pilot saw a real ’bus.”

“I do,” argued Garry.

The talk ceased as the light ship came swiftly down, across the marsh, dropping lower, leveling off, setting its pontoon body lightly into the water.

If not as experienced, in point of years, as Scott, the seventeen-year-old junior flyer at the Dart’s controls was as expert. Landings in daylight, night conditions, or in darkness, were easy for Don: because of a season of timidity concerning “getting down,” at the start of his flying practice, the youth had determined to break himself of his timidity before it interfered with his rapid progress. Alone in his uncle’s Dart, he had made practice take-offs and landings in every sort of weather and under all imaginable conditions, until he was so sure of his ship that he had no uneasiness about setting down. He realized that the modern airplane is so well stabilized, so well designed, that it does just what its pilot wants it to do—that in every case where some part has not failed, the pilot’s mental condition and its resulting reaction on the handling of the ship is what makes the difference between safe flying and accidents that result in injury or worse.

The small, wide-winged craft sent out a split crest of foam, coming swiftly closer to the Dragonfly; but it lost speed and Don maneuvered it to a point close alongside the larger craft and with his own wings just a little behind those of the biplane. Gliding up to its stop, the Dart rested quietly in the still, rather murky water.

“Hello!” its pilot greeted the others. “Did I give you a solution of the Mystery of Mystery Airport!”

“You certainly did!” Garry admitted. “Chick thought you were the flying phantom——”

“Just as the first pilot to crash thought some chance ship, lighted up by a flash of some beacon, was the ghost,” Don interrupted.

“I’m not so sure of that,” Scott spoke, taking up the thread of a statement he had been about to make before the Dart came down. “I’ve been interested in the mystery—I like spooks, you know——”

“More than I do!” broke in Chick, gloomily. Scott, laughing, agreed.

“Every fellow to his taste,” he quoted. “Anyhow, I’ve been reading up on ghosts, and talking to some of the ‘old inhabitants’ around the marsh. Want to know what I dug up?”

All three eagerly chorused agreement. “Away back in the days when airplanes were tricky to handle and the pilots knew less about aerodynamics than they do today,” he stated, “a flyer was over this swamp, on just about this sort of night,” he indicated the clustered, slow-moving, fleecy groups of clouds, some assuming the pyramid shape of thunderheads, “one of the clam-diggers at the edge of the swamp recalls it very plainly. He was out at low tide after clams when—it happened!”

“What!” asked Chick, forgetting his uneasiness and the gloomy, spooky environment in his suspense.

The aviator had appeared suddenly, coming down, through a cloud, as Scott repeated the tale told him by an old man who earned his meagre living with a clam-hoe and bucket; at the same instant another ship, diving swiftly in apparent oblivion of the first, came into view.

“It must have happened in the flick of an eyelid,” Scott went on. “As old Ike tells it, he heard the engines, looked up, saw one ship for a split second, saw the other, and then—saw them come together!”

“Oh!” exclaimed Garry, “collided, did they!” Scott completed his story quickly, after admitting that Garry had diagnosed the accidental smash correctly.

“Right-o! And they never found one of the ships. It must have gone down in Devil’s Sink.” He referred to a portion of the marsh either of the quicksand bottom sort or very similar in the softness of its muddy shallows. “And—-”

“That’s—why they found—a skeleton, there!” Chick shivered as he spoke in a hushed voice.

“Maybe.”

“But—” Don objected, “what connection is there between an accident years ago and the excitement that has gotten into some of the newspapers and made a reporter call our new development ‘Mystery Airport?’”

“Ever read the ‘Proceedings’ and other books of the Society for Psychical Research?” Scott questioned in turn.

“I saw some of them in a bookstore,” Garry admitted. “They were too dull and prosy for me. Just old stories collected by scientific men who were trying to find out whether ghosts existed or not.”

“What did they decide?” Chick spoke eagerly.

“Nothing very definite,” Scott informed him. “But I’ve gone over a lot of the dry ‘case-histories’ and I firmly believe that if somebody has done something wrong, he has to haunt and stay around the place.”

“Like a criminal ‘haunting’ the scene of his crime,” chuckled Don. “I’m surprised at you, Scott. I believe, in every case, if you could get to the bottom of it you’d find that the ghost is either produced by fraud, or else some perfectly natural things are misjudged——”

“Chick thought you were the sky spook,” broke in Garry.

“I believe that’s so in most of the cases,” Scott agreed. “But this time I think the ghost is restless, because he was careless in coming along through the clouds where he couldn’t see ahead far enough to be able to avoid other ships—and he may have caused the other ship to go down into the Sink. That makes his spirit hang around, and of course whenever it appears, it lives over all the terrible scenes of the smash!”

“But I just proved—” began Don.

“Yes, you proved that people can be mistaken,” Scott was serious. “You didn’t prove that any ship was near at the other times that pilots have claimed they saw the ghost.”

“One caught the fever from another,” argued Garry. “The first one saw something—or he tried to get out of culpability for carelessness in making his crack-up, by saying a spook put him out of control. The rest were all superstitious and the story got headway. The next pilot to see a flicker of Summer lightning and a bird flying or anything at all, was quick to twist it into a spectre, and come down to tell his story and give everybody chills and shivers.”

“I think we’ll soon find out,” Scott spoke quietly.

Surprised, the others clamored for his reason.

“This is just the sort of night that the three other pilots had, when they claimed to see the ghost of an airplane coming out of luminous clouds,” Scott stated. “It’s close, humid—storm-breeding July weather.

“Well, then, for another thing, if you check up you’ll find that the spook has appeared every seven days—and this is the seventh night since this last time!”

“Let’s go home, Don,” whispered Chick, across the narrow span of water. Don laughed.

“No, sirree!” he retorted. “In the first place, if it is pure chance, nothing will happen, because it isn’t reasonable that a beam of light from the control room search-lamp would strike a cloud every seventh night and four successive weeks. Besides, it isn’t possible that an airplane would be flying around just at the same time that light came, and that no other ship would be noticed.”

“No,” declared Garry. “My opinion is that it’s some real person who flies out of the clouds, after seeing a ship coming. Then he goes up into another cloud and is lost, and because of the first fib the pilot told to protect himself from censure by the Board of Inquiry sitting about the crack-up, all the rest believe they see a spook.”

“I think he is trying to use the ghost scare to drive business away from Uncle,” Don asserted. “Uncle has several people he can name who are none too fond of him. Any one of them might be doing the ‘spooking.’”

“In that case,” Garry was practical, “if we go up, scouting, that person will know it, and won’t ‘appear’ tonight.”

“That’s why I liked Scott’s plan when he suggested guarding the sky,” Don agreed. “It’s important, too—because Uncle Bruce is expecting to get a big airline to contract for space for its ships, servicing and all that, take-off and landing, and fuel and oil. It will mean a lot to him not to lose that contract. If we prevent any ‘spooking’ tonight, there won’t be any newspaper scarehead stories tomorrow to make the men hesitate about signing up.”

“Then let’s get up out of this stagnant water!” urged Chick, fired by the realistic explanation of the spectre. “We’ll be a sort of Sky Watchman.”

“An Airlane Guard!” suggested Garry.

“That’s it—an Airlane Guard!” Scott agreed. “Well, come in here, Don, take this Dragonfly aloft and cruise around. If you see signs of any other ship than the mail ’plane—it’s due soon—let Garry send over a green flare if it’s in the air, or have Chick fire a red Verey if it goes up off the earth or water—and you go around on wingtip to point to it and start after it, and I’ll come up on a slanting course, and we can corner the fellow, and end the mystery of the Spectre in the Clouds.”

“Why not come up in the Dragonfly, and let Don fly the Dart, too?” Garry suggested.

“The Dragonfly isn’t fast. The Dart is. If the ‘spook’ pilot sees you young lads cruising around, he’ll think it’s just a joy-hop. If he happened to see you start out—with me—he’ll suppose we are testing the visibility of the new airport lighting system—and he might try to scare up a little excitement for us, as he’d suppose. Then, if Don flew the Dart, taking off first, to surprise him, the ‘spook’ might do stunts and I’d rather be the one to handle the Dart in the night time if stunting is in order. As far as both ships flying around is concerned, what self-respecting ghost, or sensible enemy of Mr. McLeod’s, would give us a chance to drive him down and capture him if he saw two ships in the airlane waiting for him?”

They saw the logic in his reasoning and agreed to abide by Scott’s original plan.

The Dragonfly was warmed up.

Don, in its pilot’s seat, waved a hand to Scott who had shifted to the other craft, opened his throttle carefully to avoid unnecessary air disturbance as he drove away from the Dart, and then got his pontoons “on the step,” so that take-off would be easy, and lifted the three-place Dragonfly into the night.

Garry felt a thrill of expectancy. He loved the mysterious, but of the practical, worldly brand; he had no belief in supernatural things. This would be a chase against a human enemy of Bruce McLeod, airport designer and airways development specialist. Don, steady but hopeful, felt much the same.

Chick, for his part, snapped his safety belt with a little tremble of his fingers. He anticipated something fearful.

His premonition was fulfilled.

CHAPTER III

THE SPECTRE IN THE CLOUD

“There it is!——”

Chick’s voice, shrill with terror, died away, and Don, startled for an instant, almost let the glide become a dive; but he caught his stick and gunned ahead, giving up the glide they had been in.

The radial engine, though of as silent a type as any, drowned any reply from Garry or Don until the youthful pilot, climbing, had gained a good thousand feet more of altitude. Then he cut the gun and let the glide begin, so that the Dart was quietly nose-low in a gentle glide.

“Don’t go off at half-cock that way,” he remonstrated.

“No!” Garry was a trifle annoyed by Chick’s impetuous screeches. “If you insist on yelling ‘wolf!’ every time the sheet lightning flickers on the clouds, you’d better be put down—and stop trying to be an airlane guard.”

“Was it sheet lightning?” Chick asked lamely.

“Yes. There’s a storm brewing.”

“Then we’d better go home!”

“Don’t be so anxious.” Garry spoke sharply. “The storm isn’t here and won’t be for an hour. We’re going to stay aloft at least till the mail ’plane comes in. They ’re inaugurating the new ship-to-shore service and you wouldn’t want to be making a pass at the field just when that crate comes over, and make him lose ten minutes waiting for us to shoot the field and land and get the ship off the runway.”

“No.”

Don climbed again.

That cruise, however, began to be tedious. Already they had been for a good half hour aloft, cruising to and fro, mostly over the dismal, dark reaches of the salt marsh.

Don chose to stick quite closely over the area which had been the scene of one real mishap and several other narrowly averted crashes.

The spectre had always appeared over the swamp.

“I wish they’d start draining it,” Don mused, thinking of the gloomy marsh below his trucks. “Those engineers spend so much time surveying! If they’d get their men out there, and start work, there’d soon be no dark place close to the airport, and the ghost would go away. Or—if anybody should be trying to ruin Uncle Bruce’s new real estate development and the airport business, they’d see it was no use and quit!”

Having nothing to occupy his mind, as he kept the Dart almost automatically at flying speed and in level flight or climbing for a subsequent glide, the youth, depending on Garry and Chick for their first inkling of anything unusual, reviewed the strange mysteries which had upset the morale not only of the airport personnel and of the pilots, but of the residents of Port Washington and the vicinity, as well.

Four weeks before, to the day, just before the dedication of the new airport which had been opened in conjunction with the already established seaplane base and aircraft plant, an airplane had cracked up in the swamp. It had approached, down wind, over the morass that lay where the draining project would later bring airport expansion and a cottage community. Since the full night-landing light equipment had not been completed, at the newly dedicated field, no provision had been made at that time for night landings and so no one had been on watch for the free-lance airplane which had gone down.

Its pilot had not been badly hurt and had managed to attract rescuers by use of flares.

His story, told that night, and later persisted in at the Inquiry Board investigation of the smash, had been a weird one.

It had fired the superstitious air folks to hear him affirm that he had been making his approach to try out the new field, quietly, when a sudden glow of light in a cloud almost dead ahead of his nose, only a scant few feet higher, had startled him.

Almost at the same instant, as he maintained in his assertion, from within the glowing cloud he had seen the swift approach of a shape.

“It was an airplane, but it wasn’t an airplane!” he had maintained, declaring that its shape was blurred, its outlines ghostly, its position seemingly also to shake up and down, as though either the ship was vibrating dreadfully or its very shape of terror made the moist cloud stuff shudder.

“It seemed to be coming down and straight at me!” the pilot had declared. “I got just the glimpse—then I dived, and of course my engine was full gun and I power-dived and only came out of it just above the marsh.”

Then he had added the finishing, terrifying word.

“I looked up, to see what had become of that other ’bus, and—the sky was silent, deserted, dark!”

On each of the succeeding seventh days, as Don recalled, a pilot had set down, shaken and horrified, to report seeing a similar apparition of the skies, a very phantom coming out of clouds!

“It’s all imagination!” Don murmured, reflectively. “One caught the scare from the other!——”

“Don!——”

“There!—side-slip! Quick!”

Don, catching the fright if not the sense of Chick’s scream, and the surprise of Garry’s order, kicked rudder to give the banked Dart, making a gentle circuit of the swamp, a chance to shift downward and sideways.

Then he glanced to his left: common sense told him that the bank with left wingtip elevated, causing the slip to the right, and Garry’s consequent order meant that whatever gave rise to the order was to his left and slightly higher. He looked that way.

Just before a brightening shimmer of Summer lightning blotted out the spectacle, Don saw what made his flesh crawl.

Apparently lighting up a large, fluffy, steamy-white cloud with its own spectral glow, some phantom ship came fleetly forth through that misty, white screen.

Dark, almost black, yet not distinct and sharp, because of the mist he supposed, that mystical, phantasmic craft grew large—and was blotted from view by the bright flash of the distant storm.

Gone! Absolutely vanished! Once seen, for a bare instant, the strange and ghostly mirage had disappeared when the blaze of the lightning faded.

Immediately Garry, cool and self-contained, sent over the side a parachute-flare, self-igniting with the jerk as the ’chute opened to sustain the vivid, unearthly light in mid-sky, slowly dropping.

Chick cowered. Garry remained erect, calm, poised, staring swiftly above, to either side, and below.

He saw nothing. Slightly blinded by the recent flash of Summer electricity, and still being a little dazzled by the green of the flare that had ignited almost in front of him, he could not make out any distinct object in any direction.

Don, who had been looking down at his inclinometer to gauge his bank as he glided, just when the cries first came, was not dazzled: he sent a swift, questing look in every direction.

The sky was blank, except for the after-flare of the dying electrical discharge and the growing glare of the green light.

“But—was that still the shadow of the spook ’plane, that I just saw?” he muttered, inquiring of his straining eyes. If so, the barely discerned shadow was gone.

“I don’t see Scott!” he shouted back to Chick. “Do you?”

Chick, speechless, shook his head.

“He’s probably up above the clouds by this time!” called Garry; he knew how fast was the Dart. Probably, as he reasoned it, the watching pilot had seen the light in the clouds before the green flare had gone over the side. Its blaze had prevented their dimmed light from discerning the Dart, that was all.

“There comes the mail ’plane!” cried Don, waving an arm toward the North. Down the Sound, bringing the mail from a vessel still a hundred miles from land, the swift ’plane was seeking to prove the commercial advisability of lopping off delays in getting trans-oceanic mail to its destination.

They watched the fleet approach of the small ship that had been catapulted from a huge liner’s cabin deck.

“Look!” Chick’s voice was shrill.

Garry even, caught his breath. Unexpectedly, like the vision of a fantastic nightmare, Don also saw the catastrophe.

Sharply, parallel with their own course, the mail ’plane tipped down its nose.

Before it, a luminous cloud seemed to glow with a weird, unearthly light.

Down went the mail craft—into darkness—into the bay.

Sharply Don slapped his stick sidewise, kicking rudder. On wingtip he banked around, straightened, gave his engine full gun, elevating the nose, darting straight for that cloud. Still it seemed to glow!

On a full-gun climb Don made his ship climb at that cloud.

The glow disappeared.

Straight through the cloud he drove—and came out!

Except for their ship, immersed in that humid, wet mist for an instant, the cloud had been devoid of any tangible object. No other ship, hiding by some miracle of skilful piloting, had been there to dodge, to reveal itself in escaping Don’s intrepid charge.

Out of the cloud they sped.

Don cast his eyes backward. The fluff, hardly disturbed except for a swirl of fleecy smoke where their propeller had moiled up the edge of the filmy drapery, lay at the tail.

“Oh-h-h!” Again, almost inarticulate, Chick screamed.

“Dive!”

As he cried out, Garry realized that his call was useless—late!

Straight ahead of the Dragonfly’s speeding, climbing nose, in one more of those horrible, mistily glowing banks of Summer moisture, lit as if with a phantom’s phosphorescent fire, their horrified eyes saw a vision, dreadful, inescapable!

Two misty, shadowy airplanes, appearing as though silhouetted in shuddering brown against the gleaming of some infernal light, came at one another.

Don knew that his ship could not avoid adding its own crash to that cataclysmic impact.

There was not time to dive.

Already the propeller was within a hundred feet of the others!

Don closed his eyes, braced.

Mechanically he had depressed the nose by throwing forward the stick.

But there was no rip and rend of wings stripped off as they went under the trucks of those other airplanes.

There was nothing—neither impact nor blow, crash nor other sound.

Don looked swiftly upward.

The cloud was around them—dim—silent—ghostly! And dark!

And the other ships—had they dived, fallen? Or, were they but the phantoms of over-stimulated imagination?

They had come together—but Don realized that he had heard no crash.

Hastily he pulled out of the dive. Soberly he turned the nose toward Mystery Airport—baffled—not knowing what to think, what to believe!

CHAPTER IV

TEMPEST AND TREACHERY

Seeing the direction taken by Don, Garry, using the light of the ever increasing flashes in the North, scribbled rapidly and sent a bit of paper forward.

“Going back?” he asked Don in that fashion.

As a vivid blaze of forked lightning leaped across the sky, Don nodded.

For answer Garry extended his arm, outward and downward.

The green flare, floating slowly downward, lit up the swamp beneath the Dragonfly.

Looking down, Don saw what Garry meant. The mail ’plane lay in a tangled heap of marsh grass at the edge of the lighted space. A flash of lightning picked it out more sharply.

In that more accented glimpse Don made out the twisted wings and warped outlines. For a moment the more sinister apparition which had menaced the three chums had driven the pilot of the mail ship out of Don’s mind.

He felt ashamed of his lack of consideration for a man whose airplane had gone down so swiftly. He swung back and began to drop the nose.

The floating flare died out.

Chick, still searching the skies for that dreadful phantom whose advent had robbed him of all self-control and whose unexplainable disappearance had added to, rather than diminished his terror, cried out in dismay. He wanted very much to get among people, to feel the security of human companionship among older people.

Almost at once, however, Chick’s sense of decency came to his rescue. He was glad that his remonstrating call had not been heard because of the noise made by the engine. At heart Chick had, like most impulsive youths, one of the kindest, most chivalrous, natures.

Resolutely he drove out his own selfish timidity, braced himself to ignore the shaking of his nerves and muscles.

In the glare of a bright stream of heavenly fire, Don turned a face that showed great concern.

Garry guessed the reason.

The Summer tempest, that had been prophesied by heat, humidity and the gathering thunder heads, was bearing down swiftly from the North, racing along the shore of the Sound.

Its rapid approach gave Don much uneasiness.

Wind, rain and turbulent wrench of storm could be avoided by going at once to the airport. They could set down, get the Dragonfly in the hangar, and get help to proceed by safer ways to the rescue of the pilot.

If they tried to set down in the water of the marsh, the storm might break upon them before they could rescue the fallen pilot, always supposing that they could get him out of his ship.

Garry, scribbling another note, passed it up.

Don read it in the next flicker of the intermittent lightning.

“It is dangerous to try to go down. But his life may hang on quick aid.”

Don, reading what Garry had written, nodded, kept the nose down, added a spurt of the gun to be sure of clear cylinders, and then side-slipped to lose altitude as quickly as he could. He brought the ship to a level once more, and, while Chick sent over white landing flares to help him chose his landing without risk, made contact with the water.

While the Dragonfly sped with diminishing momentum across the wide stretch of water they had formerly used, Chick and Garry were busy.

From a conveniently located small locker Chick drew out and uncoiled rope with which to secure the Dragonfly if they were not able to go aloft and escape the storm. If they had to “ride it out” he wished to be able to stake down the wings and tail, to prepare the ship as well as possible against the tear and stress of high winds. He hoped that the airplane would run close to the edge of the open water. There, he knew, was a small dock, on the widened end of which stood a small, two-room shack used by a boatman who rented his small dories for crabbing excursions into the channels of the swamp.

Garry, with quick hands, drew out a first aid kit from a pocket in his cockpit, glancing into its box to assure himself that it contained the liniments, bandages and adhesives he might need. Garry had taken a number of lessons in first aid and instinctively thought of the work of mercy he might be called upon to do.

Don, maneuvering the Dragonfly up to as close proximity to the old dock as the safety of wings and propeller would allow, signaled to Chick and called for one more white flare.

Dropping the floating light into the water, to augment for them the illumination provided by the almost incessant flickers of lightning, Chick sprang up, and began to climb out on a brace and the wing-step at one side while Don balanced him on the other.

Expertly Don caught the rope end.

It was plainly to be seen that the storm would be down upon them before they could take off safely and get high enough to avoid the moiling currents of the stormy area. Bringing the ship as close to the dock as he could, by flinging a bight of the rope over a dock piling, Don let the wind drift its tail outward. Chick, on his side, clambered carefully forward across the lower wing until he could fling his part of the rope over another wooden upright.

Quickly, but carefully, they worked the ship around so that it was sheltered somewhat by the dock planking and to the leeward of the old house.

By climbing out to the wingtip, gingerly so as not to injure the fabric and with each movement setting his weight on the supporting framework, Chick, his terrors forgotten in action, held a flying wire with one hand, bent far outward, and managed to get his fingers over the gunwale of a dory tied under the wharf.

He drew against the pull of the wind until he could get the dory and the low wingtip close enough together to enable him to step across.

Swiftly he untied the painter of the boat while Garry aided Don to use every available inch of their rope in securing the Dragonfly against the pull and thrust of wind, the tossing waves that must soon fling the ship to and fro.

Their tasks completed, Don and Garry, one on the wharf planks, the other balancing the light flying craft, waited until Chick could scull the dory close alongside the fuselage.

There he stepped back onto the wing bracing, steadying the dory as Garry and Don entered it.

“Hang on!” he urged, as Don caught a bracing wire to keep the two craft together, using his hand to fend off the rub of wood against the Dragonfly’s fabric body. “I’ll break into the shack and get oars.”

Agile, supple, quick, Chick clambered to the planks.

He ran around the small building, old, dilapidated, weather-worn.

The door, he recalled from earlier visits, was toward the more solid shore a hundred yards beyond, from which a narrow runway enabled visitors to cross deep, mud-bottomed channels.

To Chick’s surprise, the door stood ajar!

He dashed in, waited until a flash of the swiftly coming electrical storm gave him light, located the racks of oars at one side, secured a pair and hurried out.

“Take flares!” he urged. “You might need to signal. I’ll stay here!” He was anxious to make amends for his earlier weakness by braving the storm, guarding the Dragonfly as best he could, in spite of the spooky look of that open door of the deserted interior of the shack.

Agreeing, as soon as they had secured the signal lights, Don and Garry sculled for all they were worth, got the dory away from the airplane, and then took their places, rowing hard for the stricken shape of the mail ’plane half way down the Southern shore.

Chick hastily went from post to post, making certain that their knotted ropes were secure.

Then he turned back to the old hovel.

Hoarse and angry, the thunder rumbled, ever louder.

Across the water, in the dying light of the last flare they had ignited, he could see Don and Garry, their bodies rising and bending in rapid rhythms as they put all their strength behind the oars on their rescue errand.

The door of the shack, when Chick came to it again, stood as before.

He hurried in.

The wind began to blow in short, sharp puffs. A vivid fork of light thrust its fire from cloud to earth. A crash and rumble followed.

Chick shivered; but it was not from fear of the storm.

Somewhere within that small boathouse came a low moan! Hollow, hard to locate, it chilled Chick’s very marrow.

He braced his shaken nerves, standing just inside the doorway, his presence hidden from peering eyes by some old oilskins behind which he had hurriedly dodged.

A glare of burning air, a blue-white bolt of fire, threw the inside of the place into brightness akin to day.

In that flash Chick’s eyes caught the huddle of a body in a corner.

At first terrified, then made calm by the thought that it must be the mail ’plane pilot who had managed to crawl along the swamp edge to shelter in the old place and needed instant attention, Chick crossed the room.

As he did so a glare of light more vivid than the others showed him for a fleeting instant the face of the man lying in a heap.

“Doc Morgan!” Chick cried out in amazement. “Doc”——

The man was a sort of general helper around the airport, not very keen of wit, nor deft of hand; he aided when ships had to be trundled out of the hangar, and swept up the yards, and did other odd jobs.

“Doc” had earned his nickname because he was always gathering herbs which he maintained were of great medicinal value. Curiously enough, the concoctions he administered to the amused airport personnel often proved to be very helpful. Therefore “Doc” was forgiven his dull wit and liked for his good nature.

But what was he doing there, in the supposably untenanted boat shack?

Morgan stirred, groaned. Chick bent down, “‘Doc’—are you hurt?”

The man stirred again, and then Chick, with a stare, moved back a step. The man was muttering. An empty bottle, reeking as did his breath with the odor of cheap alcohol, gave the clue to his condition.

A fierce gust of wind swept through the place before it banged the door against its frame with a crash that made Chick jump. Before the slam of the door shut out the fire of a bolt that came close, Chick saw a bit of paper caught up by the draft and sent through the air. He ran to the door, threw it wide, turned, and, waiting for the next gust, and its accompanying flash, he located the paper—secured it—caught sight of its marked surface, thin, inked lines on light tracing paper—and cried out, in disgust.

“You traitor! You’ve taken some of the plans for the new all-metal ship! This is one! Where are the others?”

CHAPTER V

STORM-TOSSED WINGS

Puffs of cool wind began to bend the tall grass while Don and Garry bent and pulled back at the dory’s oars.

Rapidly the intensity of fitful flashes in the North increased, and the storm drew closer.

“Think we can make it?” gasped Garry.

“Hope so!” Don responded over his shoulder.

Ahead of them, but fully exposed to the blast of the coming tempest, lightning flashes revealed the torn, broken shape of the mail ’plane. If they could get there before the storm broke in its full fury they might rescue its pilot from the added menace of turbulent waters.

Already, while they were a quarter of a mile away, they saw that the time was all too short.

“Don!” called Garry, “I thought I saw a sort of path on the shore, along the water, when the lightning came that last time.”

“I thought this was all marshy, soft ground,” commented Don, “but it might be that we could get around to the mail crate quicker if there was solid earth to run on. Let’s try!”

They let the increasing wind drift them, aiding their efforts.

Bright and fierce, a flare of electric blue came across the sky. In its light they made out what looked like fairly firm earth, running in a swiftly narrowing strip from the mainland, a promontory jutting in a curving line into the grass-covered waters. If only that jut of land extended far enough they thought it possible to reach the smashed airplane by a safer route than the dory could afford. Already it dipped and rolled, as they drove its nose on the wash of foam into the soft bank between the grasses.

Holding tightly to a handful of the sturdy vegetation, Don began to progress into the bow. From the windward side Garry dug his oar into soft bottom, steadying their craft as well as he could.

The wind swept the stern around into the grass, but Don managed to get a leg over the bow, to test the firmness of the bank.

“I think it’s solid enough to hold us,” he cried, and got out of the dory, being careful to cling to the rope at the prow, lest his chum be drifted beyond the patch of solid ground, separating them and leaving Garry to battle alone against the surge of wind and water.

“It’s safe!” Don added. “I’ll hold the painter, Garry. Come on. Be careful to leave the oars in the bottom or the grass might pull them out of the boat.”

“I will!”

Garry picked up his first aid kit, stowed the oars, crawled forward and tumbled to a yielding sod which, nevertheless, did not break through.

Guiding themselves by the steadily increasing succession of lightning gleams, their voices drowned in the quickly following growls of thunder, wondering about the Dragonfly, about Scott, probably aloft in the Dart, Don and Garry went from the dory, tied to a root, along a perilous and unknown path.

Don, in the van, had to part clumps of tossing, cumbering grass to test the solidity of footing before he went ahead; Garry, clutching his kit and steadying his partner when a foot would miss the sometimes narrow band of safe path, followed.

As a glare of vivid fire, followed almost instantly by a peal of angry thunder, revealed the upthrust wing of the smashed craft within a few feet, to one side, Don stopped.

It had been apparent to them for several yards, as they parted the clumps of grass, that the way went no further.

“Can you lift me up, make a ‘back’ for me, do you think?” Garry asked as he carefully put down the first aid kit on the path they had just traversed.

Don, choosing his stand on what seemed to be the firmest spot—an old spar or block of driftwood embedded in the mud—bent forward, his hands braced on his knees. Lithely, with his gymnasium training to give him confidence, Garry put his weight on the elevated perch of Don’s back and leaped, forward, upward and outward, over the mud and water, as a chain of fiery light split the clouds to the roar of thunder.

Don, in that vivid flare, saw the lithe figure seemingly poised between sky and water, its outflung hands seeking for a grip on the leading edge of the wing that was closest to them.

Leaping up as soon as the weight left his supporting back, Don saw those hands strike their target—but the light died as it seemed to him that Garry slipped. Peals of celestial cannon drowned a cry if there was any. With eyes still blinded by the fierceness of the last flash, Don could not make out whether Garry had been able to hold his grip or if he struggled in ooze and quagmire, sinking, helpless.

“Garry!” he shouted.

From the North came another blaze of blue-white light.

Don gave a relieved cry. Garry, one foot braced against the junction of fuselage and flying wire, one hand clinging to the wire, was safe!

The moiled waters, reflecting the furious discharges of fire from above, were foaming across under the wind’s whip, and Don saw that if Garry did not find the object of his search quickly, it would be too late. Already the salty spume lashed his face, the fabric of the airplane quivered and shook to the beat of waves, and sunk in the soft mud, while wind under the wing failed to topple the whole craft onto the end of the promontory only because its trucks lay in clinging mud and steadied the ship.

From across the end of the grassy bank Don saw the distant glow of two red flares, smoking and guttering in the wind.

Chick was signaling. Two red flares!—did that mean the air signal, for an airplane to land, the storm call “proceed no further!”

Or, Don wondered, was Chick himself in danger?

“I can’t go!” he muttered. “Oh, Garry—hurry!”

Garry, revealed by a fresh, and even more vivid stream of heavenly fire, was lifting something.

Don saw him wave, as if urging him to go away.

Then something heavy seemed to come against him, almost taking him off his feet. Instinctively he clutched it, recovering his footing.

“The mail sack!” he gasped.

In the next vivid flash Garry came, hand over hand, along the edge of the wing as the whole ship toppled forward, and the change of angle, freeing its trucks from the mud, enabled the wind to get under the wings with telling effect.

As Don steadied Garry after his drop to the ground, the lightning showed the menace of the toppling airplane.

Backward they leaped, Don with the heavy sack of precious mail.

Just missing them, the wing came down, the fuselage rested for a moment on the supporting earth and then earth, craft and all tumbled and torn by the wind, slipped on into deeper mud beyond the solid earth left just a foot beyond Garry’s toes.

“Let’s get back!” gasped Garry, shaken.

“But the pilot?——” began Don.

“He wasn’t there!”

Don realized, as they turned to retrace the Way, that the pilot could have had time, scant but sufficient, to leap clear in a back-pack ’chute and that it would be impossible for them to comb the marsh for him in the rapidly coming blackness, wind and rain.

As rapidly as they could, finally breaking into a run when they got clear of the most dangerous and slippery end of the promontory, Don and Garry raced toward the beckoning flares.

Carrying the mail pouch, impeded by it as it caught on the restraining grasses, Don followed Garry. Garry, his eyes straining, tried to detect the figure of Chick by their guiding light, but he saw no figure!

As they came into the clear space near the boathouse, with wind whipping the first flecks of rain into their faces to add its cold warning to the sting of salt spray torn from the growing crests of waves, Don and Garry paused, almost stunned.

The last ruddy glow of the flares, and the white fires almost constantly leaping across the zenith, showed them two forms emerging from the door of the hovel, toward the planks that led across the marsh to solid ground.

They were struggling. They were locked together. One was large, the other small and slight.

“Chick!” yelled Don, putting speed to his flying feet.

The flares died. In a glare of light the larger figure broke free from the smaller as they came to the boarding.

The lightning died out, leaving the sky a black, thunder-echoing void. The earth beneath was cloaked in the pall. With blinded eyes Don stopped, fearing to crash into Garry just ahead of him.

They were too far away to see, in that masking blackness, what had happened.

The last light had shown the smaller figure reeling backward, on the edge of the planks, it seemed.

There was nothing to do! To run forward might mean being precipitated into the marshy channels.

They waited for the next flash.

With the perversity of storms, the lightning seemed exhausted for a long, mind-torturing moment. When next it flared up, two anxious hearts seemed to drop like leaden weights from two tight throats where they had striven to constrict the breath.

Bare and silent lay the narrow footway across the marsh.

Dark and sinister the water moiled in the channels beneath it.

Thick and brooding, the heavy grass bent and seemed to whisper mockingly in the wind.

“Garry!—where did Chick go?”

“Don—I don’t know! I can’t see!”

They ran forward while the light lasted.

The next flashes gave them light to get to the edge of the footway over the marsh. They stared toward the grass, the water, the bare and unrevealing planks.

Chick was not visible. Neither was his adversary.

Beyond the end of the planks the grass began again. Don dropped the mail pouch: Garry, his kit forgotten, deserted far behind them in the eel grass at the promontory end, ran across the planks. Into the hovel Don turned.

On the narrow, twisting path beyond the planks Garry searched, unable to see far because the grass stood so high.

In the hut, with wind roaring around it, Don strained his eyes to gain some truth from the upset table, the overturned lantern, the evidences of strife and of struggle that the lightning showed as its fire came leaping again through the doorway.

Quickly Garry retraced his steps to be met on the planking by Don.

“There has been a fight!” cried Don. “Did you find anybody—see anything?”

“No!” answered Don, “but—listen!”

As the thunder reverberated and echoed, followed by a deep silence, pounding feet came along the path they had recently used, from the promontory. They turned, staring into the South, the light coming at their backs from the sky fires.

A man in a pilot’s helmet and jacket, corduroy trousers and high boots, running in a staggering, uneven course, with an arm swinging limp at his side, hailed them.

“Help!——”

The figure stopped, wavering, and crumpled on the earth.

Swiftly Don and Garry ran to the man who lay prone on the sod.

“Oh!” he moaned, and then, recovering slightly, he gasped, “can you get me to—doctor?—hurt—inside!”

“It’s the mail ’plane pilot!” cried Don.

He saw his duty, and there was scant time in which to do it.

The first winged cohorts of the storm clouds had broken to shreds overhead. Its first fury was expended. From the North came the gathering furies of its second, and more terrible onslaught.

If Don could get that Dragonfly into the air and climb out of the turbulent area, he could get the pilot to some medical man; at the same time he might carry on that mail!—and send searchers to find Chick.

Much depended on the safe delivery of the pouch Garry had recovered. It was the first of what might be a successful series of ship-to-shore mail flights, from vast ocean greyhounds, in swift airplanes. Its successful delivery meant a great future for Don’s uncle who had started the idea with the inception of his new airport.

“Yes!” Don cried, bidding Garry help him to lift the pilot to his feet.

To get that tethered airplane, the Dragonfly, started, warmed up and aloft, carrying pilot and mail, was his immediate concern.

Ably Garry aided him.

Before the fury of the storm broke again, their storm-tossed wings cut the air, climbing swiftly through the darkness that seemed breathlessly waiting, still ominous, waiting—while Don flew his best.

Then, from the North, the storm furies leaped.

CHAPTER VI

“THE THING THAT NEVER WAS”

Stunned by the realization that the man who worked around the airport seemed to have betrayed those who trusted him, clinging to the roll of tracing paper that was his evidence of that betrayal, Chick faced Doc Morgan in the dark hovel until the next flash of celestial fire showed him a lantern standing on the small, rickety table at one side.

Hastening over to the table Chick fumbled on it, and in the drawer which remained partially open.

He found a card of paper matches.

Quickly lifting the lantern slide and turning up the wick, Chick ignited a match, applied it to the burner and adjusted his light.

“Listen here—” Doe Morgan, in his corner, struggled up to a sitting posture, groaned again and then took up his own refutation of Chick’s accusation. “Listen, Chick! I ain’t a traitor, no such thing I ain’t!”

Turning, in the feeble glow of the lantern as its wick burned with a queer, fitful light, Chick’s face showed his antagonism and unbelief.

“No, sir,” the man contended, “Doc Morgan, he may be ‘queer’ but he ain’t no such a thing as a traitor, not him!”

“Look at this!”

Chick waved the rolled tracing.

“——And this!” He indicated the overturned bottle that reeked of alcohol of the cheapest kind, lying on its side at the edge of the table.

“You thought you’d celebrate getting away with the plans of the new all-metal ship, and nobody would know about it, off here in the marsh!” Chick accused Morgan fiercely. Treachery was hateful to Chick. The man had been allowed to stay around the aircraft building plant and the new airport because he was a harmless sort of scatter-brain, able to do simple chores, willing enough, and always “doctoring” people with his herb remedies, coming to the swamps for the peculiar forms of sea grasses and weed that he contended had medicinal value. He had been trusted.

“How can you say you aren’t a traitor?” Chick challenged, motioning with the paper he clutched, keeping the table between himself and the man he no longer trusted, watchful, alert, angry.

“What’s that, you got there?” asked Doc, making an effort to get to his feet. He fell back, groaning, and Chick, in some surprise, noted that there was a handkerchief made into a rude bandage about his head.

“You know, well enough!” Chick spoke through the rumble and thud of thunder whose echoes reminded him of heavy cannon balls rolling along on cleats fastened to an inclined trough, as thunder was simulated in the local motion picture house for one of its “sound effects.”

“I never saw that, what you got, no I never!” declared Doc. “Here I come in the swamp, I do, for salt water weed to mix my herbs, and I see a storm coming fast, I do, and shelter here.”

“That’s good!” scoffed Chick.

“It’s truth, it is so! I come here, I do, and—” his face, in the spectral yellow gleams from the lantern, and the contrasting glare of intermittent lightning showing through the door, looked pale and weird, “—and I see—something I never thought I’d see outside of a nightmare, so I do——”

Chick’s attention was arrested.

“What do you mean,” he demanded. “‘See what you wouldn’t see outside of a nightmare!’ What is that!”

“I can’t tell you, that I can’t! It was—too awful!”

Quickly Chick recovered from his momentary dismay. The man was trying to divert him from his accusation, he decided.

He made a gesture toward the emptied bottle.

“That’s what made you see whatever you think you saw!” he declared.

“No!” Doc got slowly and unsteadily to his feet. Chick watched. “No,” Doc reiterated, “I never touched that till after I saw—It! I come in here, I did, I declare—to shelter. Then I saw—It. It was in the corner, and I saw it, I did so! Terrible, it was! Green in the hair, and green in the face! And greenish hands! And all slimy and terrible, like it had come up out of the ooze, it was so!”

Chick crushed back his tendency to believe, and to be startled.

“After—you’d emptied that!” he insisted, gesturing toward the old bottle.

“No! No such thing. I knocked that over. It set there, it did, and I hit it, I jumped so. I hit the table, and I must either of got upset stumbling over my own feet or—It—hit me! That’s when I took that—what was left in the bottle, to steady me, I did so!”

Chick, disgusted, unwilling to be hoodwinked, realizing that he had more important things to consider, refused to listen any longer.

The Dragonfly lay tied to the wharf piling: the wind was rising. His chums were off in the dark waters of the swamp on a rescue errand.

“I can’t bother with you,” he snapped. “Tell it to Don’s uncle, when we get out of this.”

Doc remained silent, steadying himself by resting a hand on the wall, holding his seemingly aching head with the other.

Keeping the table between them, and braced against the ruse of a push against it to upset him, Chick opened an end of the tracing and verified his earlier guess.

The tracing certainly looked like the rough sketch for an airplane, with most of the bracing and internal structure of the fuselage inked in heavily, with the wide-spanning, thin, speedy “slotted” wings sketched in more lightly, with the tail assembly marked on, and with innumerable sets of figures, in ink, underneath the drawing.

Swiftly he rolled it up and put it back into his upper coat pocket, being sure that it could neither shake nor be dropped out by folding it over, jamming it down as far as he could, and snapping a safety pin he saw in the drawer across the pocket top. Doe watched him with a woebegone look, as Chick judged it to be.

“I don’t know what you’re hiding, I don’t that! Nor why you say I’m what I declare I ain’t no such a thing—a traitor. But I’m going on home, and doctor me up myself some.”

“Go on!” Chick braced for a rush, a surprise.

None came.

Moodily, with head bent, Doc walked to the doorway and out. Following him, Chick saw him, picked out by the flashes, cross the planks and disappear in the winding path.

“Who was that?”

Scott, coming around the side of the hovel from the wharf, made his presence known, asking the question sharply.

“Doc Morgan,” Chick responded. “I found him here. He had finished off a bottle, and he had some tracings. I guess I forgot and left them out on the designing room table when we were talking about our plan for tonight.”

“Tracings! You don’t say? Let’s see them!”

“In the morning!” said Chick, eagerly. “You ought to go and help Don and Garry. Where’s the Dart?”

“Over in the shelter of the grass, across the water, there. What are the other two doing?”

Quickly Chick told him where Don and Garry had started for in the dory. They scanned the water. The dory, invisible, hidden and held by the wind among the weeds, told them no story of its abandonment.

“I guess they’re at the crack-up,” surmised Scott. “Light two red flare signals, Chick. Get those two back here. If I don’t get back to the Dart she’ll never get above the storm in time. The same for the Dragonfly. Get those boys back here! If Don hurries he can get up aloft in time.” Moving away he added, “After the storm we’ll search.”

Chick climbed to the struts over a rocking, tossing wing of the tethered Dragonfly, secured signals from the fuselage, and as he saw them set and ignited Scott hurried off to get his own lighter ship out of the danger area. Chick refused to go along, preferring to risk Don’s less experienced piloting. He would not desert his chums.

“By gracious!” he exclaimed to himself, “I wonder if there are any more of those plans in the drawer of that table? Doc might have tried to hide them, stopped to celebrate, got too ‘tight’ to know what he was doing, and struck his head when he staggered and fell. That would account for the drawer being open so the paper could blow out—I’ll go and have another look!”

He hastened back into the hovel, investigating by the flicker of the lantern, wind-blown, but staunchly holding its own.

“Funny!” commented the youthful searcher. “Why did he have only the least important plan—the sketch? Maybe he has the others on his person! I ought not to have let him go. But I was so——”

He paused, his words choked back into his throat by a strange sound. Had something struck the hovel? A blown limb, crashing against the side, could have made that heavy, but dull thud, hard to locate.

To his horror, before he could locate the source of the crash, a low, sepulchral voice spoke!

“Go!—Go!—I am the Thing That Never Was—the Man Who Never Lived! Go—or I take you with me—down—down—down-n-n-n!”

Chick whirled to face about. In a corner, behind him, half out of the floor, as it seemed, was the shape of the Thing—terrifying, and yet surprising. Green, dull and glistening, as if of plastered seaweed or wet rubber was its head. Heavy, glistening, ooze-covered was the covering upon its partially disclosed torso. Green, glistening, but dripping with slimy weed were its waving, beckoning hands.

Transfixed, rooted to his tracks, Chick gasping, stared.

Seen in the unearthly, fitful flashes of lightning, the yellow lantern flicker and the dull refracted red from the burning flares outside, the apparition was horrifying enough.

But Chick felt his muscles unchained as the figure grew in height and advanced toward him, its long, glistening, weed-spattered arms outstretched. Like a streak of fleeing terror Chick raced out of the door.

There he paused, uncertain. It was safer in the open than in the room: the signals and the brighter light outside the cabin would enable him to see better that Thing of Fear if it came forth.

Out it came, speaking no word. Terrified, Chick ran. But for all its flapping encumbrance of weird draperies, it was swift. It caught the youth. Terror chilled his blood but he struggled. Then his courage came welling to him. If those hands could grip they must be human, and if shins kicked in desperation could evoke human growls of dismay, he faced no spectre, but a flesh-and-blood creature.

The man, in his horrid garments, was searching with exploring fingers while he tried to hold the squirming, kicking Chick who strove to be free, to escape.

There were shouts from the other side of the hovel; suddenly Chick felt his inner pocket ripped open, and the Thing—or man—was away over the planking, running fleetly and with sure steps. He knew that way!

After him went Chick, into the twisting, swamp-bound paths.

Nor did he return until long after that!

CHAPTER VII

ABOVE THE STORMS

While he fought the blasts of wind that tried to twist the Dragonfly out of control, climbing to get beyond their influence, Don tried to decide on the best course.

His ship was not equipped for navigation. No compass or radio was provided to aid him in such a difficult situation: otherwise it would have been easy to rise beyond the storm levels, to set his propeller toward some predetermined objective where he could land safely and be within reach of a hospital to care for the injured mail ’plane pilot.

“But I don’t know wind direction at different levels,” he reflected, catching the ship as a gust of fierce wind caught the tail and swung the ship around, broadside to the wind.

“I don’t dare to run before the wind, because it has grown so black and we’ve drifted so far off by now that I might not get near the base,” he added to himself.

Garry, in the second seat, realized how difficult the situation was for the youthful pilot.

A run before the wind, he understood, might take them out over the ocean before they knew their danger: there it would be a question of time only before the gas would be exhausted.

Long Island, with the Atlantic to its East and South-East, with the broad Sound along its Western side and New York’s bays in the South, was not the best place over which to fly “blind.”

The safest course, Garry thought, was to go on climbing. Don, without being able to exchange ideas, felt the same way.

As the gusty wind got under the wings he operated his controls to right the ship; when the tail lifted, he compensated with the elevators, always climbing when he dared. Rain swept in stinging sheets across the wings and into their faces, cold and stinging, making the wings heavy, but Don gained slowly but surely in his fight for altitude.

Finally they emerged from the clouds, and soon were able to rise beyond the worst of the turbulent air.

“I’ll go higher,” Don determined. “I want to be safe from the upsweep of warm currents; they upset the ship too much.”

As he gained altitude, going close to the “service ceiling” or safest and highest altitude at which engine power was not dragged down too much by the lightness of air, Don saw, with dismay, that a worse complication confronted him.

The storms they had overcome were not the only ones existing.

After the humid, torrid day, storms were visible to the North, to the East and to the West, as far as his eyes could probe the lower strata of air.

Theirs would be a poor chance if he flew toward the South: although only the beginnings of turmoil lay in that direction, the sea was waiting, and Don’s only choice seemed to be to stay aloft as long as he could, hoping for a lull between the periods of stress, through which he could drop to a lower point, get his location and perhaps make a landing.

With unexpected fury an eddying uprush of air took the Dragonfly in its fierce grip, twisting and turning it, flinging the right wing high.

Swiftly, and with more than his usual force, Don threw the stick to a position that should correct and right the ship.

His heart turned cold, a sickish feeling came into his stomach.

Somewhere in the heart of the control cords something parted.

On wingtip, the nose began to fall.

Instinctively, knowing that in that position the rudder functioned as an elevator, Don changed the position of the stick, using the rudder bar to elevate the rudder, gunning on full power to pull up the nose.

In that position, however, while the nose came up momentarily, saving them from a dive, Don understood that they would very soon slip, on wingtip, sidewise, down into the turbulence below them.

Garry, thanking his good fortune that he had studied airplane design with Don, during their work in the design and blue-print departments, acted.

He knew each rib, brace, strut and cable of that ship, could picture their positions from the multitude of drawings and of blue-prints he had handled.

With swift accuracy he kicked through the flooring, light and very easy to demolish.

Plunging his hands through the openings, bent low, he probed with hurrying fingers for the loose cables of the elevators.

He found them.

The tug he gave informed him that the break of the cord lay between him and Don’s stick. He could operate the elevators, but Don could not.

With the cords tautened he waggled them, shaking the ship.

Don turned his head.

He discerned Garry’s bent position, realized what it meant.

Garry, though not a trained pilot, knew the operation of the controls and could co-operate with Don.

With a swift movement of the stick Don began to right the ship as it started its sidewise slip.

Immediately Garry, knowing that the elevators would then function in their proper capacity and that the rudder no longer could lift and depress the nose, worked his cables.

Before the ship could fall off again, Garry drew the “flippers” upward. The engine, full gun, helped their effort, the ship began to surge forward, gaining flying speed in the proper horizontal course.

Watching the nose, his head lifted, his position cramped, the broken end of the cable in one hand and the slack of the other side held in his other fist, Garry watched the ship’s fore and-aft spirit level because his mission was to hold the nose on a level.

Don, with the customary signal of his arm, pointed straight ahead.

Garry agreed with his decision to maintain a level course, flying into the wind.

The gas gauge showed that they had fuel to last several hours. From the other instruments it was evident that oil feed and pressure, and other necessary functions, were operating correctly.

If they could fly beyond the worst of the storm area, in the time their fuel reserve gave them, they might, by dint of careful cooperation, get down without serious disaster. Don looked back, pointed ahead.

Garry nodded.

Thus they flew on. Don knew that Garry, bent almost double, stretching his neck upward, was in a straining, difficult posture.

It would be a question of his muscular ability to hold himself against the torture that must come with the unnatural pose: aching muscles could in time compel him to relax, perhaps to let go of the cable.

“Good old Garry!” whispered Don to himself. “If it’s in human power to last, he will be the one to stick it out!”

It was torture, as Garry came to know before they ended that flight.

Ignorant of the drift of the wind, unaware of the real course, only able to guess at the flight direction by the position of the rising moon, Don surmised that they were flying in a somewhat Northerly course.

Ahead he saw, with thankful eyes, an edge of a cloud dispersing its fury in rain. There the flashes of celestial fire diminished in intensity.

Finally, with hearts that thanked a power greater than storm force, by dint of careful manipulation of signals and of controls, they made a landing in a field, amid quiet, storm-washed hills!

CHAPTER VIII

THE HAUNTED SWAMP

Drenched by rain, almost blinded by the incessant lightning, Chick drew up on the narrow footway among the grasses that the wind swept against his face.

“I’m lost!” he muttered.

All around him, as far as his sight could reach in the flashes, tall, waving, unbroken marsh grass showed.

“Somewhere I took a wrong path,” Chick told himself.

Shivering, he stood, fumbling at the buttons of his coat.

“That man who tried to make me think he was a spook, calling himself ‘the Thing that never was, and the Man who Never Lived,’” he said bitterly, “tore my coat pocket.”

He put a hand inside his garment to estimate the damage.

A great feeling of elation crowded out his momentary shudder of fear on realizing his dreadful situation.

“He didn’t get—the tracing!” cried Chick to the storm-swept grass.

He laughed in exultant delight.

“That Doc!” he exclaimed. “He was in such a hurry that instead of getting the tracing I had folded down on itself, he grabbed out the envelope of stamps I had in that pocket!”

Crowded into a long manila envelope Chick always kept a loose lot of assorted postage stamps, ready to “trade” for new varieties to add to a collection he was making.

In his haste the unknown—but easily guessed—adversary had caught hold of the fat envelope, crushed down as Chick had pinned in the other paper. Released, it had popped up. That had been his trophy. Chick danced and shouted triumphantly.

“He’s welcome to all those Bavarian and Venezuelan duplicate stamps!” cried Chick, making sure that the precious tracing was secure from any chance rip of the pocket allowing it to drop out, “and if he can make anything by selling a hundred cancelled American two-cent stamps, he will do better than I ever did!” He felt elated; but the distressing situation he was in came back to him and his face sobered in the glaring light of the tempest.

“I see the boathouse,” he told himself. “I guess I’d better go back there, and not try to get out of here in this storm.”

By guiding himself in the revealing light from the skies, he managed to get back to the right path, pushing through clutching clumps of the soggy, clinging grass that had hidden the way out but did not wholly conceal the way back. He had heard the Dragonfly, knew it had gone up.

Once more sheltered he shivered in his wet clothing, but made the best of a bad condition by righting an old, rickety chair and turning up the lantern wick till it gave a better light.

“Now,” he remarked to himself, “let’s see—Doc was here, and for all his denials I am sure he had taken the tracing—maybe others! I remember that I was sorting out the drawings of the new, all-metal ship, to make blue-prints in the morning. Scott came in and I guess I was so excited at the prospect of guarding the airlanes that I left those drawings on the big table.”

There it would be easy for Doc, sweeping up, to find them, to abstract any—or many.

“But he might have told the truth about not ‘celebrating,’” he said, thoughtfully. “He never has any money to buy big bottles of alcohol. If he had been paid by anybody for the new designs, he wouldn’t have had the one I discovered. He must have been waiting for somebody else to come.”

He recalled the course of events that had transpired. Had the “other man” come? Was it he who had played ghost? Chick wondered, clutching his torn, soggy coat as tightly about him as possible. Not that it warmed him much; but the act was involuntary as his mind focused on the weird apparition he had seen.

Instinctively his eyes went to that dark, gloom-crowded corner of the hovel.

In a lull of the storm he seemed to hear something gurgling, slapping, like water against pilings. It was too clear to come from the channels beyond the closed door.

“I wonder—if there was a trap door—” he meditated.

Summoning his courage he walked over to the corner. To his surprise he discovered, in the gloom that had concealed it, an unclosed flap of the flooring, leaning back against the wall. In the dull light from the lantern it had not been noticed, against the similarly dark wall boards.

“It’s a trap door to steps so the boatman can get down to the dories he keeps tied under the place,” Chick decided.

He did not care to explore the mysterious depths below, however.

Closing the square of flooring on the fury of the water beneath, he returned to his chair.

“I know about the Man who Never Lived, now,” he told himself. “It was Doc Morgan. He saw I had the tracing. He told me all that made-up stuff, and then went out. He came back, over the dories, maybe, under the place, and came up the ladder, in oilskins and rubber cap and gloves. Pouff! I guess that’s all there was to the ghost.”

That made him wonder if, in some way, they might find an equally sensible explanation for the spectre that had appeared and vanished so mysteriously in the clouds.

“But Don flew right into that cloud!” Chick objected to his own hopeful theory. “There wasn’t a thing there.”

He sat, shivering with the chill of his wet garb, wondering how long the successively approaching storms would continue.

Long hours seemed to pass. Chick got up, exercised, flailed his arms and did gymnastic exercises to promote circulation. Nevertheless, time dragged slowly.

The intensity of the storm lessened: lightning came more fitfully, rain ceased, thunder grumbled and ceased to crash, dying away in the South. Chick went to the door, looking out.

“There are stars,” he observed the bright sparks showing through the drifting, scattering shreds of the tempest, “maybe I ought to try to get home. They’ll be worried about me. I wonder where Don and Garry landed and if they got down all right.”

They had, but far up the Hudson.

Swamp life began to make itself heard—and felt.

Fish leaped, hungry for insects. Frogs began to sing their uncanny songs. Mosquitos, made ferocious by the cooling air, attacked Chick in swarms. He retired to the house, closing the door, killing as many of the pests as he could.

The bites decided him against a foray into the marsh paths. He had read of several cases of people, lost in marshy country, who had been dangerously bitten and infected by the swarms of nocturnal pests, swamp mosquitos.

He sat down again, drawing out and spreading the map before him on his table.

Damp, softened, the paper was very hard to handle. He wondered, as he studied it, why Doc had chosen that special one, if it was all he had taken.

“It doesn’t show much of the real construction detail,” he mused. “If I’d wanted to sell plans, I’d have taken the detail drawings—the new pontoon design, the special tail construction plans, the details of the way the plates would fit together for strength and lightness. Oh, well, maybe Doc took what first came to hand and was looking it over—with his bottle to help him think it was valuable!”

He looked up, startled.

“Was that a step?” he asked himself, straining his ears.

With instinctive caution he slipped the curled paper back into his coat, buttoning its loose buttons across his chest.

A low, hollow thumping came to his tense ears.

“What’s that?” he wondered. “Where is it coming from?”

He kept mouse-still, listening.

“It’s—at the door!”

His heart was in his throat.

“Has Doc come back?” he watched the door. Something—or someone—was fumbling at the latch, striking knuckles against the wood.

In spite of his earlier assurance that the supposed spook had been only a man made horrible by light and queer clothing, Chick felt a chill strike to his marrow.

The latch clicked.

Slowly the door began to open.

With wide—staring eyes—Chick fixed his gaze on the widening crack.

He jumped. With a slam the door came inward, banging against the inner boards.

In the dark square—there was nothing visible.

He summoned his wit and by sheer force of will made himself run to the door. He looked out. The path, the planking, the platform on which the house stood, were devoid of sign of human life.

He ran back, closing the door. He dragged the table against it, bracing it against another strange attack. He stood over the trap door to prevent its uncanny opening without warning.

Then the lantern flame flared up, guttered—went out!

A sound, half squeal, half groan, assailed Chick’s ears as he cowered in the dark hovel. He realized at once what it was.

Pushing the table across the floor, the door was being opened.

CHAPTER IX

ONE MYSTERY—OR TWO?

Slowly the table grated back across the floor of the hut.

Then, to Chick’s intense relief, a cheerful voice hailed him.

“Ahoy, the boathouse! Who’s in there?”

“It’s—Chick—Chickering——”

“Gosh-a-mighty!” Chick sensed a familiar ring in the exclamation. “In the name of all-possessed! What are you doing in my boathouse?”

The door thrust the table back, a dark form showed in the rays of the moon that peered from the edge of scattering clouds, and Chick, with a great sense of relief, recognized that his newest companion was Toby Tew, who operated a small motion picture “palace” in Winter and eked out a meager living by renting dories to crabbing parties in the Summer.

“Show a light!” he ordered Chick. “What made you blow out the lantern?”

“I didn’t. It went out.” Chick clutched the arm of the big man in his heavy oilskins as he thrilled to the touch of human contact. “Mr. Tew, did you see anything—hear anything?”

The other laughed.

“Sort of spooky, hey? No. I guess I was part of the ghost, and your excitement furnished the balance. I saw a light when I started down channel to see to my dories after the blow. ‘A light!’ thinks I, ‘that’s a how-dy-do!’ So I pushed the door open, and got out of range, case it was some bootlegger run in out o’ the blow. I heard you coming out so I dodged across and got behind a spile. Thinks I, ‘I don’t want any bootlegger to bore me. If he wants to shelter in my boathouse, let him,’ thinks I, ‘but I won’t try collecting rent—not in the kind of lead the bootleggers uses to pay their taxes!’”

“I’m glad it was you,” Chick said, and on Toby’s earnest question as to his reason for being there, Chick spoke in fullest confidence.

He knew Toby Tew, as did all the youths of Port Washington and its vicinity, knew him for a kindly, good-humored, open-handed man. No parent was ever visited because prankish youths “borrowed” dories and returned them with am oar missing. No party of boys lacking funds had to forego crabbing expeditions as long as Toby had spare dories not in demand for pay. Any Winter evening there were plenty of spare seats at the picture theatre for young men who wanted amusement but were out of pocket money—and they always paid when they could!

“Um! Gosh-a-mighty!” exclaimed the boatman-picture exhibitor, when Chick had related the suggestions of Scott, the ensuing flight, the coming of the mail ’plane, the spectre visitation and its vanishment, and the events that had followed, “in the name of all—possessed! You don’t say! Doc!—why, Doc never stole in his life!”

“Somebody had to bring those designs here,” Chick maintained. “Doc was here when I came,” he gestured toward the bottle and the upset condition of the hut, revealed by the refilled lantern; Toby, who had made a foray on his reserve can of kerosine for the lantern, set the utensil in its place.

“Doc never done that! Gosh-a-mighty! I’ve known that fellow for a lifetime, almost! In the name of all-possessed, though, who would of come up through my trap door with oilskins and green rubber gloves and a bathing cap on? And what for? And Doc did say he saw the same——”

“It’s easy to say you ‘saw’ something if you mean to ‘be it,’” Chick explained. But Toby shook his head.

“He wouldn’t go that far to try to throw a scare into you,” he remonstrated. “And Doe seldom uses alcohol. More’n that, there’s some mighty funny goings-on around this marsh, of late—mighty funny.”

“I know it!” Chick agreed. “That spooky airplane and then the two ghosts crashing together—Scott said some old-timer around the marsh had seen it and remembered about a crack-up years ago and thinks it’s the ghost of the pilot who caused the smash, unable to rest, haunting the place; and—from what we saw—I begin to wonder.”

“Not me. Gosh-a-mighty, son, there’s a whole heap of easier ways to account for it than that. Supposing the airport beacon was lit, say—flashing around. Supposing your airplane was to fly across that ray just when it came onto a cloud. How about the shadow?”

“Don showed how that could be, when he came in,” Chick agreed, “but that won’t account for the crash of two airplanes.”

“But if Scott had took up the Dart—in the name of all-possessed!” Sitting in the chair the boatman slapped his knee. “That’s what it was. The Dart flew one way. You was going another.”

He paused to emphasize his next words.

“The two shadows showed, coming together!——”

“That won’t explain it,” Chick interrupted. “The airplanes were of the old style—like the war Jennies, or old-style biplanes.”

“In that queer light, and with your minds keyed up to expect something——”

“But how would it help if that did explain the spook tonight? We weren’t flying around the other times!” Chick was unconvinced.

“That’s so!” Toby rubbed his chin. “Besides, how does that work in with this about the mysterious airplane design being found here. Let’s have a look, what do you say?”

Chick uncurled the soggy paper, carefully, on the table.

“In the name of all-possessed! Nobody’d steal that! It don’t mean a thing, does it?”

“Well—only the general body design and strut placement. And I don’t see why they sketched in wings and control surfaces, on a structural skeleton.” Chick was puzzled.

“Hum! You know more about that than I would. Son, it’s a mystery!”

“Is it one mystery—or two?” Very soberly Chick looked up. “Do you see how taking this tracing fits in with the spectre in the sky?”

As Toby shook his head and bent again over the tracery, Chick went on, in the yellow lantern light.

“We thought the haunting might be by some enemy of Don’s uncle, to ruin the airport business,” he argued. “If that is so, then this about the tracing is a different mystery.”

“Gosh-a-mighty! You’re smart for your age!”

Toby looked up admiringly. “Now, then, what reason would you say made anybody want to take this—” He put a stubby finger on the tracing, looking up with a curious intensity in his gaze that surprised and startled Chick a little.

“I—I guess I give that up.”

“I guess you’ll have to! Son—look at this thing. Hold it up to the light!”

Astonished, Chick did so.

“Notice anything odd about it?”

“Some of the ink has run——”

“That’s part of it, son. The part that has run is——”

“Wait!” cried Chick, thrilling with a discovery. “The wings and the struts, and some of the ‘empennage’—the tail assembly—is done in India waterproof ink!——”

“Not alone that.” Toby became very serious. “That’s no design of an airplane, my lad. That’s—but, here! Gosh-a-mighty! I’m forgetting that you’re sopping wet and cold, and the folks at home will be having a search party out after you. Let’s get my dory and I’ll row you down to the ‘base.’” He caught up the lantern as Chick picked up the tracing.

“Wait!” begged Chick. “If it isn’t an airplane—what is it?”

Lantern in hand, Toby turned to him.

“It’s the hull of an old-time sailing brig!” he declared.

And with that he added a third mystery—or didn’t he?

CHAPTER X

A CHARM TO CLIP GHOST WINGS

Landing flares dropped by Garry were still burning as Don cut the ignition of the Dragonfly. From a house adjoining the field they were in, a farmer came running to the airplane.

“Where are we?” Don called eagerly.

“Is there a place near where they can take care of this pilot?” cried Garry. “He’s hurt—we don’t know how badly.”

The farmer came closer.

“Hurt, eh!” He attended to the more important question first. “I don’t know of any place for miles where you could take him. But I can telephone old Ti-O-Ga. He’s an Indian. Lives a few miles back from the Hudson. Everybody knows him. He’s a kind of ‘medicine man’ and he’s a wonder with broken bones.”

He turned, informing Don, over his shoulder, that the field was a few miles beyond Catskill, a town in the Hudson River valley.

The pilot, his senses recovered, but suffering, spoke up. “Old Ti-O-Ga? Why, yes. Get him. I’ve heard of him.”[1]

“Go with the gentleman, Garry,” Don suggested. “When he has done his telephoning he may let you get the airport and tell Uncle Bruce what has happened to us.”

Garry went away while Don remained with the pilot, keeping his flares going for light and on the chance that a passing automobile on the adjacent road might stop and go for a physician. Don was not deeply impressed by the offer of Indian aid.

Garry returned very quickly.

“I got the airport,” he told his chum. “They were worried about us, and of course your uncle feels badly because we still have the mail.”

“I’m going to signal a passing car,” Don said. “If I can get the driver to take me to some place where I can get fuel, I’ll fly back.”

“I’ll stay with the pilot,” Garry volunteered. Don had no trouble in inducing a motorist to give him a “lift” to a garage at some distance. Ti-O-Ga came in a car while Don was gone. Old, but straight and sturdy, the Indian surprised Garry: he arrived in a Ford, wore American clothes and, if reticent, spoke to the point.

“Drink!” he ordered the pilot, offering a small cup of liquid taken from the car. The pilot, putting the liquid down his throat, sat in his cockpit quietly for a moment.

“Say!” he exclaimed, “that’s great stuff, Big Chief!”

“You feel like walk?”

Helped out, with some muttered exclamations as his limp arm was put to a strain, the man admitted that he felt much stronger.

“I take you to house. Strip! Find what is wrong.”

The pilot, assisted by the farmer and by Garry, made slow but steady progress to the farmhouse.

There, while he waited, the Indian gave Garry a steady, and very curious observation.

The youth began to feel uncomfortable. He had a feeling as though those bleak, steady eyes were boring through him. He shifted uneasily.

“I be done soon,” Ti-O-Ga remarked, rising at the call of “ready” and moving toward the next room where the pilot had been prepared for an examination, “then you tell me all troubles.”

“How did you know I had troubles?” Garry was amazed. “I have—but how did you know that?”

“I be back.”

Garry sat quietly in the small, cozy living room, waiting.

In a surprisingly short time the Indian returned with the farmer.

“Chief Ti,” the farm owner remarked to Garry, “Chief Ti is a wonder. He’s got the man’s arm set—not a bad fracture, he says. No internal injuries, and what he gave that chap to take will put him on his feet in short order. Ti’s a wizard at doctoring.”

“He said I had troubles,” Garry exclaimed. “How did he know?”

“Don’t ask me,” the farmer retorted, smiling. “Old Ti is a queer one and he can read people the way you’d read a book. Can’t explain how he does it; but I can see he’s taken a liking to you—and just take my advice, buddy, and let him do what he wants, answer all his questions, and don’t argue about his ways. He’s Indian—but they say he is the closest thing to a real magician this side of the world. He showed me some things, once, like the Hindu fakirs do—creepy, but interesting.”

The Indian beckoned to Garry.

“You come,” he said, “I give you charm.”

“A charm!” Garry repeated. “What for?—” Then, recalling the advice just given him, he rose and followed the tall, dark figure. “I thank you, I mean to say—but I don’t see how you know——”

“I know.”

That was the end of the conversation. Garry, at the other’s sign, climbed into the old Ford beside the driving seat which Ti occupied.

Rapidly, skilfully, he was driven into the back country.

The ride was very short, it seamed. Good speed and clever handling of the wheel on a road free from traffic helped.

“Well,” Garry mused, “this is a queer business. First we try to guard the airlanes and see a spook crash in the sky; then we get lost and have to set down at the very best place—from the way that pilot was handled. Now I’m bound for some Indian tepee, I guess—to get a charm. For what? How does he know anything, and what does old Ti know?”

He soon discovered.

“This is my house.” The car stopped in front of a small, but neat frame building, a cottage whose windows gave out cheerful light. Garry, accustomed to stories of frontier Indians, gazed in astonishment as he was ushered into a neat, well-furnished living room with a telephone in one corner. At a wave of the slim, gnarled hand he sat down, quiet and mystified. From a rear room a woman, not altogether Indian, and very pretty in a bold, strong-featured way, brought in cold meat, bread and cocoa which she put on a handy table. Invited to eat, Garry realized how ravenous he was and attacked the food with good will.

“You like rest?” the Indian asked when the girl, probably a daughter, removed the dishes and cups.

“I’d rather go back and help my chum.”

“He not back yet. Rest! You sleep, huh?”

Garry shook his head; but a drowsiness seemed to be creeping over him; his muscles felt heavy and inert; he struggled with the increasing desire to sleep, feeling some uneasiness as the steady eyes held without blinking, watching him intently.

He relaxed, and began to dream an uneasy, garbled mass of disconnected flashes. He felt as though he drifted above a dark, dismal swamp and he saw again that spectral ship flying toward him. The dream altered. He seemed to be watching Chick, in some dim light, examining a scroll or roll of paper-thin, almost transparent.

Soon he awoke.

“I didn’t mean to drop off—excuse me,” he mumbled.

Then his faculties asserted themselves. He sat up, alertly. The Indian!—had he put something in the cocoa? Had he used the same methods Garry had seen in stage demonstrations, to get a person into a helpless state in which they did as they were told and answered questions in a dreamy, far-away fashion?

He looked around.

Through an open door he saw the tall, red-skinned man putting some objects into a small, dark-looking little pouch. The strings of its mouth he drew together as he returned to nod pleasantly at Garry.

“Feel all good?” he asked. Garry nodded.

“I——”

The man did not allow him to go on.

“You troubled by ghost in the sky,” he said. “You not think right answer about why! You take this.”

He held out the small pouch, several inches long, a little more in depth, apparently filled with some unrevealed contents, its string of rawhide tightly knotted to hold the mouth puckered, and a small, very odd wax seal in red, showing a swastika-cross, covering the top.

“Take,” he repeated. Garry held out his hand, hesitatingly, lost in wonder that the man knew about the spectral visitations that mystified the Airlane Guard. “Hear, now. Put over head.” He gestured. Garry, widening the strings, slipped the pouch over his head. “Keep inside coat. Go home. Put in box for seven day! Not touch! Then—open!”

“Why?” demanded Garry, surprised but suspicious.

“Why! That is good charm, boy! You worry about ghost wings.”

He made a clutching motion of fingers and thumb, as though wielding a pair of scissors.

“You see ghost wings! I make charm to clip ghost wing!”

Garry, puzzled, stared; but the man tapped on the table, a slim, dark youth entered. Ti-O-Ga said “Goodbye” and before he could muster any comment, Garry was ushered to the car, the young Indian took the wheel and, fingering his pouch, tucked inside his clothes, Garry rode away.

“A charm,” he muttered, “a charm—to clip ghost wings! Hope it works!”

1. While the name is necessarily changed, there lives, in the Hudson River valley an aged Indian “medicine man” whose herbal remedies and other curative methods are famous over a wide area: his “magic” is less widely known, but is in line with the possession of certain secrets of Nature and of mental ability of a high order and amazed the youth by his businesslike and plainly successful methods.

CHAPTER XI

THE CHARM SEEMS TO WORK

When Don and Garry, leaving the pilot to mend his bones and recuperate in the farmhouse, brought the mail down, they found Chick fairly bursting with his adventures.

His story had other interested listeners besides the youthful pilot and Garry. Doc Morgan sat beside Don, Toby Tew occupied a chair by the designing room table, and the airport owner, Bruce McLeod, shared a wall bench with the control room operator, a close-mouthed, black-eyed man who was none too well-liked by the personnel of the new venture.

Everyone gave close attention while Chick related his adventures.

“In the name of all-possessed!” exclaimed Toby, “if that was put in a movie, I’d be able to pack the Palace when I showed it. I didn’t hear all that, last night, Chick-o!”

“I was too excited to remember all the details,” Chick responded. He turned to Garry.

“You and Don got lost, didn’t you?”

Don nodded, smiling.

“Garry had all the adventures,” he said.

Pressed for his story, Garry told about the Indian, his strange insight into the youth’s mind, what he did, and what he gave.

“I claim you ought to put that in your movie, I do,” Doc told Toby. “I know old Ti well. He learned me, he did, all I know about herb doctoring.”

“I went up there, not long since,” Toby stated. “Wanted to hire him to make a ‘personal appearance’ on the stage of the Palace with a film that was made up Catskill way, with him in it. Couldn’t make any deal with him, though. But—Gosh-a-mighty! Think of him mesmerizing Garry! In the name of all-thunderation! That’s queer!”

“It isn’t any more queer than the chart—the tracing you say is a drawing of an old-time brigantine,” declared Don. “Let’s see that, now.”

Chick went to the filing cabinets devoted to storage of accepted design tracings, hunted through a folder, kept under lock and key, and put the tracing on the table.

An exclamation caused them all to turn.

The control room operator was staring, astonished and pleased: he leaped to his feet.

“So that’s what you found!” he exclaimed, moving quickly forward. “Brigantine-nothing! That’s a sketch I—er—mislaid. I guess it got mixed up with the regular stuff and was brought in here—but how did it get to the swamps?” Chick watched him with narrowed eyes.

“A sketch,” Chick thought. “Oh, yes! Part of it in faded ink and part of it in India waterproof ink, the sort they use here!”

He did not voice his suspicion. It came to his mind that the control room man would bear watching. Through him, Chick decided, they might get some clue to the mysteries they had encountered.

“Before I touch it,” the man continued, “Mr. McLeod, just take a look at the lower, left-hand corner and see if my initials are put in the angle of what is meant to be the bow of a new-shaped fuselage.”

“Yes,” admitted the airport manager, with a glance at the sketch. “J. V.—John Vance. Take it, and let’s get out of here so the boys can go to work. They’ll be paid by the aircraft company, and it’s a good thing. They’ll be paid! If any more trouble comes to our airport, I guess Doc, and Scott, won’t draw any pay checks.”

Scott, coming in from the adjoining office, laughed.

“I’ll ‘haunt you’ if I don’t!” he chuckled.

“I wish we could solve the mysteries!” Garry spoke earnestly: he felt sorry for the harassed man who had put all his available capital into the new airport, who had enlisted his friends’ savings in the swamp draining and expansion project. The engineers, Garry knew, had been “called off” and their activity in the marsh had been stopped. It was of no use to add further expense, increase available runways or hangars.

“Solve the mystery of how I am going to meet unpaid bills,” growled Bruce McLeod. “You’ll please me enough if you do that!”

“Uncle,” Don jumped from his seat on the table edge, “it was partly my fault that the mail was held back all night-—”

“Oh—no!” The older man shook his head.

“It was, in a way!” Don insisted. “I should have flown straight here and tried to beat the storm, but I prevented the mail from coming in by going above the storm and getting lost. Won’t the steamship company give us another trial?”

“I don’t know. Haven’t bothered them.”

“Why not try again?” Garry suggested. “All pioneer work has to fail before it succeeds. They ought to let you have another chance.”

“I suppose they would.”

“See!” urged Don, “Scott could meet the ship. He’d never dive for any ghost,” with a grin. “He likes spooks!”

“I’d like to bring in the ocean mail, too,” Scott agreed.

“Well——”

“You’re elected!” Chick exulted. “It’s as good as done. And with, the chart tracing identified and claimed, it doesn’t make any difference how it got into the old boathouse. Maybe I ought to apologize to Doc for accusing him. I do! I jumped to the notion he had taken it but he is proved innocent because he wasn’t anywhere near the control room—and we don’t know but what the paper blew out a window and was picked up by some visitor to the airport who went on a crabbing trip and put the paper down there by chance.”

Chick felt that his explanation was rather lame, but he made it in an attempt to show Doc Morgan that he was no longer suspected of being a traitor to his employers.

For some strange reason it began to seem as though the Indian’s mysterious pouch had some virtue.

At any rate, everything became quiet around the airport.

The seventh day arrived, and on its night the chums watched the dark skies without reward.

No apparition of an airplane appeared: no pair of phantom ships materialized to enact their collision and disappear.

With the spectre of the skies inactive, the rest of the mysteries also dropped into the background of attention. Don was busy with his work on the tracings for the all-metal airplane which he was helping Scott to create.

Garry studied airplane design while he prepared and photographed the multitudes of blue-prints that had to be made for each new model the aircraft corporation planned to try out.

Chick was kept fully occupied: tabulating, filing and procuring for the builders such blue-prints as they required, engaged his whole time.

His amateurish effort to watch the control room man had brought no fruit: after a day or two Chick had given up that activity.

“Well,” remarked Don, as the trio stood on the control tower balcony, about to leave after a futile vigil, with no developments to report, “the seventh night has come, Friday, the thirteenth is almost past—and we can——”

“Your uncle wants to see you—right away!” Doc Morgan interrupted.

“What’s the matter?”

“Scott was to fly out to meet the Caledonia—to pick up the mail and fly it in! Scott’s been hurt by a prop that flew off its hub——”

Three excited faces turned to the stairway.

“He might want you to fly the mail!” cried Chick.

“I hope he does!” Garry told Don. “What a chance!” Don kept his hope unvoiced. But he did hope!

Unaware that their excitement made them join Don to answer a summons not meant for them, Chick and Garry were at Don’s heels when he entered his uncle’s private office.

“What a break!” the harassed airport executive grumbled. “I took your suggestion, as you know, Don. The Caledonia is bringing special mail pouches from Liverpool. Scott was warming up the Dart. Just when we need the ship and the pilot most—the propeller hub loosened, the casting broke or it wanted oil and burned out. Whatever happened, Scott’s out of the running, and so is the Dart. I sent for you——”

“Mr. McLeod!” Chick broke in, forgetting manners in his excitement, “we went over the Dragonfly today! She’s in apple pie order. Can’t Don take her aloft? Can’t he fly the mail?”

“Can you?” The man turned to his nephew.

“I can—but how does Scott pick up the mail?” The maneuver was explained to him.

“Can’t Garry and Chick go along?” begged Don, generously including his comrades. “They could help a lot, and maybe make up by helping me for the slower speed of the Dragonfly.”

It was arranged.

Eager, excited, with a possible contract for mail flying at stake, three earnest airlane enthusiasts got their flying togs and necessary articles from the disabled Dart, signal lights to identity the new ship, warmed up the Dragonfly, and were ready to take off.

“I’ll radio the Caledonia about the change,” Mr. McLeod said. “Now—boys—do your best—and be—careful!”

“Oh, we will!” Chick waved a hand from the cockpit. “Anyhow—we’ve got to come through. We carry a charm to clip ghost wings, you know!”

Chick always boasted a trifle too early!

CHAPTER XII

DON FLIES THE MAIL

Taking off into the July south-wind, Don waited only long enough to observe the regulation compelling an airplane to be well beyond the airport limits before turning. Then he began a turning climb to nose into the East, crossing Long Island.

Although their course did not take them near the swamps which had been so closely connected with their mystery—or mysteries!—Don glanced in that direction.

Garry, behind him, busy adjusting the tube of the student’s communication helmet by which he could talk to Don, did not see what the pilot noted. Don shook the ship gently. Garry looked up.

Chick, behind them, getting a life belt inflated from an air bottle, because this would be a part of the mail flight requiring him to run a slight risk of immersion in the sea, looked up at the same time.

Don’s hand, waved toward the swamps at the left wingtip, as they came around, saw a curious object over the swamps.

They were too far away to note it with much certainty; but Garry was sure that the queer, ungainly thing rising steadily into the air was one of the aircraft whose horizontal blades, above the fuselage, enabled it to take off and rise without first attaining the flying speed required by an ordinary airplane. Its huge propeller blades acted both as power and support surfaces.

“An auto-gyro,” Garry said into the helmet communication tube.

Don shook his head.

“What did you tell him?” Chick bent far forward to shout to Garry.

“Said it was an auto-gyro!”

“No!” Chick had sharp eyes. “It isn’t the modern kind, anyhow. It’s what they call a ‘helicopter,’ Garry.”

Garry looked a second time, carefully.

“Chick’s right,” he murmured to Don. “He says it’s a helicopter—it has the lifting blades that let it rise straight upward and then it has a ‘tractor’ propeller forward that sends it through the air horizontally. It can go higher by giving the horizontal blades more speed, stay almost stationary by adjusting speed, or settle lower by slowing the blades. The tractor prop gives it forward speed. Chick’s right.”

Don nodded. That had been the reason he shook his head, to correct Garry’s terminology, because all the more modern auto-gyros he had seen employed an adjustable-angle horizontal set of blades for both upward and forward speed, and had refined the tractor propeller at the nose.

“But what is a helicopter doing over the swamp?” he wondered, “and where did it come from?”

With a meeting arranged between the amphibian Dragonfly and the big trans-Atlantic liner, there was no time to investigate.

“Does that helicopter have anything to do with the mystery?” Garry spoke through the Gossport tube.

Don could not give an answer.

“It might,” Garry continued. “Only I don’t see just how. The spook ships we saw come together in the sky were old-fashioned biplanes. They weren’t real, either, because you flew right into the cloud, Don.”

The pilot nodded. Their speed rapidly took them Eastward, and away from the swamp; but as he set his course, bearing slightly North, crossing one of the Island’s flying fields at a good altitude and with Barren Island’s new Bennett field back of the right wing’s trailing edge, he puzzled his brain a great deal about that strange ship rising from the swamps. Why was it there at all? Had it been forced to settle there? Or—did someone keep it there? If so, he thought, for what purpose?

“With the airport so handy, nobody would store a helicopter anywhere in a mucky swamp,” he decided. “It must have been a compulsory landing.”

With the lights of Coney Island, far to the right, and of Long Beach, and the Rockaways showing their Summer activities more nearly under the trucks, Don nosed out over the sea.

There he opened the throttle almost full-gun.

They must meet the liner as far out as possible. The fuel supply had been calculated to take them a hundred and thirty miles out and back with the essential safety reserve; Don had a notion to stretch that distance a trifle, because every mile the airplane saved the ship before the return would mean that much more rapidity in bringing in the mail.

Many ships came up over the horizon, were passed, and receded behind the tail.

Chick’s sharp eyes first discerned the special signal carried for the occasion by the liner they sought to meet.

“Good work,” Garry commended as Chick poked him three times and indicated the tiny trio of white lights set above a blue one on the masthead of the approaching boat, just coming up, it seemed, over the horizon line.

He gave Don the position. The youthful pilot shifted rudder and altered the course somewhat, gunning up to full speed.

“We will meet her ten miles further out then we expected to,” he murmured, pleased. That would mean faster time back for ten miles more of the distance from shore, and ten miles at their speed as contrasted to ten miles at the liner’s best, compensated for the difference in rapidity of flight between the Dragonfly and the faster Dart that could not make the flight.

They bade fair to establish a mail ship-to-shore record.

Chick sent over the flash-rocket that signalized their approach.

The vessel’s searchlight leaped to life, probed for and touched their wings, darting swiftly aside to avoid blinding the pilot.

The liner came on at full speed. Don dropped the nose, cut the gun and approached at an angle calculated to bring down the amphibian to the water at a point near, to one side of, and just ahead of the course the liner pursued.

The vessel’s lights looked beautiful, seen from the air. Chick and Garry thrilled to the wonderful spectacle. Don’s elation came more from the precision movements with which the mail pouches, buoyed with a self-igniting water flare on the buoy, went over side in the glare of the liner’s searchlight.

Calculated with skill, favored by good control, Don’s line of descent set the amphibian’s pontoons on the fairly smooth sea in a line that sent the liner sweeping by his wingtip with not a dozen yards to spare.

Tossing by in her wake, the buoyed pouches, accentuated by their marking light, were in a direct line with the airplane’s course.

Garry motioned to Chick.

His part was to clamber to the strut, cling to a bracing wire, catch up the light buoy.

Garry’s office was that of observer, to align Don’s maneuvers with Chick’s activity. Don had done well, so far: Garry would give him all the aid he could to complete the maneuver.

Seeing them safely past, though shaken by the ship’s turbulent wake, the man at the searchlight swung it onto their tail, to give Chick all the light possible.

Chick saw the buoy bobbing closer.

“A point to the right, Don!” Garry called into his tube. “He can’t quite reach—that’s better!”

An instant later he spoke again.

“Cut the gun, Don!”

The Dragonfly, skittering along on the top of the moiling wake began to settle into it, more shaken than before by the immersion into a swirl of cross-currents; but the instant of delayed speed was all that Chick required.

His outreaching hand stretched on straining muscles.

Fingers alert and agile gripped the rope bound around the buoy.

“Full-gun, Don!”

Up, and out of the danger of an upset, with engine roaring, they rose.

Chick, clinging to the mail pouches, held on.

Garry, stretching out his arm, as Chick swung inboard, caught the buoy and gave Chick the use of both hands to cling in the increasing blast of air caused by the climb.

Almost, for an instant, Chick’s heart fell into his flying boots: spray-wet, a wire slipped in his grasp!

“Cut!” Garry called to Don.

Leveled, with power reduced, the ship, for an instant, lost its climb and barely held safe margins of forward momentum.

In that instant Chick mended his grip, catching a strut.

With the mail pouches drawn to the cockpit floor, with Garry, his hands free, aiding, Chick got quickly and safely back to his place.

“Oh-kay!” he shrilled, delightedly, as he snapped on his safety belt.

Gunning up at Garry’s relayed signal, Don made his climbing turn.

They were pointing straight for the airport when he revved up to his full power.

The mail flight would be a success.

All they had to do was to fly straight, top speed, set down and be applauded. They need not cross the swamps of so much mystery and fear. They could come in from the East, landing sidewise to the wind. Don flew the distance to the point where they sighted the airport with his heart singing to the tune of singing wires, laughing with the purr of the motor. The successful termination of the mail flight was in sight.

Then the mystery helicopter struck!

CHAPTER XIII

WAR MANEUVERS

Intent on getting their mail pouch to the airport in record time, the eyes of Don, Garry and Chick, in the Dragonfly, were peering forward and downward to locate the wind-cone, get wind direction and save every precious second even during the approach to the runway.

Unexpected, startling, disconcerting, there came, not a hundred feet in front of the nose, the roaring hiss of a rocket rising to burst, in a brilliant, eye-stunning flash of vivid white just ahead.

Don instinctively side-slipped.

The flash, coming without warning, upset his self-control, made him think that he might be plunging his chums into some unseen danger. To speed into that area of still blazing fire was unthinkable.

Don’s side-slip got the ship away fifty feet: then he caught the wings, brought the ship to its forward, level flight.

Roaring upward, a second messenger of terror, with its blazing tail, seemed to be coming straight under the right wing. Garry, seeing it, screamed a warning into the helmet communication tube.

“Don—one’s coming—bank left!”

Don kicked rudder, moving the stick to tip the wings. He gunned up, in the bank.

The ship swung, almost on wingtip.

Again almost ahead of the new swing, came that terror from below.

Don saw it. He skidded out of the turn by giving excess rudder, caught the skid, and swiftly adjusted stick and bar to get on a level keel.

His quick wit told him that they were almost exactly at the altitude where those deadly fireworks were bursting.

In their excited, upset state all three youths supposed the rockets were the result of some sort of celebration. The real meaning did not occur to them.

One thing they all realized was that they were over an area of the utmost danger: no mind could foresee the track of bomb or rocket.

“They don’t see us, don’t know we’re up here!” Chick muttered as Don planned his next moves with quick and cool precision. Don had regained his self-control.

“I’ll dive, to get away with the greatest speed!” Don had decided.

Nose down, engine full speed, he dived.

The needle of the altimeter began to hasten its backward swing.

A brilliant shaft of white struck upward, picking them out, throwing up around them a sea of vivid illumination.

Instantly Don changed his tactics.

To level off, as he intended, to come out of the dive with still a fair margin of altitude to give him ease of handling well above earth was impossible. The searchlight might prevent him from seeing the ground, might blind him.

He was plunging straight down toward it.

Full-gun, he drew back on the stick. Up tipped the nose.

Wires sang with the fierce wind. The ship trembled.

At nearly two hundred miles an hour the ship began to climb in the huge arc of a “loop.”

Don had purpose behind his shift of plan.

While he had never executed it in darkness, he recalled the maneuver known as an Immelmann Turn, said to have been devised by a German war ace, by which altitude above an adversary was gained swiftly, with a change of flying direction.

As the ship soared on its vast curve, it came, soon, to the top of the loop. It was precisely “on its back,” upside down. The controls were heavy, inert in response.

Had he maintained control elements in the same position the engine should have carried the ship, with its speed almost nil, just to the point where the nose would have dropped by engine weight, acted on by gravity.

Then, going down on the descending side of the wide arc, it could be caught, at the bottom of the loop, leveled, and sent onward.

Don did not delay for that to happen.

Instead he shifted the stick far to the side, holding it there.

Before the nose dropped, the slight forward speed enabled the ailerons to act: the wing dropped, the other came up, and since Don held the slick steady, the ship, from being on its back, executed half of a “barrel roll,” so that it was right side up, and, naturally, at the top of a big circle, pointing its nose exactly backward from its original direction.

Quickly Don caught the ship’s wings as it turned on its fore-an-aft axis.

Thus he had climbed to the top of a big loop, had turned the ship from being upside down to the correct flying position, facing back on the course.

He kept the throttle full open, flying level for an instant.

They were looking away from the search-lamp. Its beams no longer menaced Don’s clear vision. Besides, being so much higher, the rays were spread, diffused.

But they were going back, and for all that Don knew, the force of rockets might still enable the missiles to reach them.

He knew, with sureness, that no chance celebration accounted for the rockets, by that beam of light coming up at them from a spot where no searchlight should have been!

He wanted to be doubly safe, to return to the proper course.

He began, almost immediately, a banked turn, at the same time going upward. In that climbing turn they both gained altitude and returned gradually to the proper course. Chick clamped his gauntleted hands.

“Good work!” he screamed in shrill elation.

Garry, too, commended, his voice more subdued as he realized that his tones went through a tube directly into ear outlets clamped close to the young pilot’s head.

“Fine, Don!” he complimented the flyer.

Don nodded his appreciation.

His face, though, was still creased with lines of concern.

“That’s somebody with a deadly purpose!” he murmured. “No fireworks were being sent up for fun. They were meant to upset us. Who could be so mean? Where did that searchlight beam come from? The airport? I was too excited to be able to trace it—right in my eyes, the way it was.”

He peered over the side: the rays were gone.

The nose was coming toward its proper point. Don adjusted his controls. They had first made a great circle, outward from its center, and upward in its arc. Then they had continued to climb, but in an arc that was on a different plane.

It took them far out over the swamp.

Garry, sighting the airport, saw that Don brought the nose to its proper line with the revolving beacon as the beam flicked past in its blinking circuit of the skies.

Chick, staring, with neck craned, over the side, saw something far more deadly.

“Garry!” he yelled at the top of his capacity, “tell Don—helicopter coming—up——”

Garry caught the call, but not its import.

He followed the line of Chick’s pointing arm.

Precious seconds were thus expended.

The strange, menacing craft gained an advantage in the delay of locating it and of discovering its purpose.

Don had to be told. Then he was in such a position that the left wing hid the object of Garry’s excited explanation.

Garry, over the edge of the wing, saw that the helicopter, its horizontal blades bringing it higher, the tractor propeller drawing it forward, rose toward them on a slanting line that seemed meant to bring the odd craft up under their own ship.

Chick, as Don altered the course to get the wing out of his line of vision, sent over a parachute flare, lighting up the scene with its white, revealing gleam.

Don saw their adversary.

From that had come the rockets: he felt sure of it. Flung out, or discharged from some outboard contrivance, their ignition powder had sent them in calculated proximity to the Dragonfly—for some deadly purpose!—to put the ship out of control, no doubt!

“There’s a man in that cockpit!” Garry told Don, better able to see past the swiftly revolving horizontal blades as Chick’s flare turned night into day beneath them.

Chick, looking, saw more.

“It’s—it’s—” he could hardly make his lips form the words. “It’s the—Thing that never—was—the Man who Never—Lived!”

He saw the green of the head covering, the slick, glistening, formless body in its slippery oilskins, the flicker of light reflected from shiny rubber gloves.

Up at them came the helicopter, its course calculated to fall on an angle that would drive them upward, or turn them away from the airport, or—if Don sought to side-slip—bring them on a level with that dreadful Thing at its controls.

What then? In any maneuver they could execute, Don wondered, what would that Thing do?

CHAPTER XIV

THE SWAMP DEMON

Slow and methodical in his mental processes, Garry was rather stunned by the situation the chums were confronting.

Don, climbing, listened for information. None came through the Gossport tube.

Chick, alert, with an impulsive quick flash, got an inspiration.

To dive meant going in line with the flight of bomb or rocket, or—if that strange Thing in the helicopter really was deadly in its intent—bullets.

A side-slip would be no better for them.

Their climb did not get them away quickly enough. Perhaps the Dragonfly had superior climbing ability, better maneuvering capacity; but no ship could outfly those messengers of fire—the rockets!

“Garry!” Chick prodded his chum.

The older youth turned.

“Tell Don—a lot of barrel rolls!”

Garry saw the utility of the maneuver. They had already executed a half-roll, turning from upside down to level. One after another, in succession, a series of barrel rolls would get them, sidewise, away.

They would lose very little altitude.

Best of all, the stunt would send them off in an evolution that would make it almost impossible to catch them, by angular direction of the missiles, because Chick knew a variation—and gave it.

“Tell Don—barrel rolls, and reverse rolls!”

Garry realized the value of Chick’s wit, relayed the idea.

Down went a wing. Up went the other.

Over and over, the Dragonfly revolved on its tail-and-nose line.

Three rolls followed one another.

At the end of the third, Don checked the ship.

Down went the nose. Short was the dive, to gain speed. Up came the nose.

With the wing that had swung upward before now down, he went into a triple reverse roll.

On the descent of their dive the dying flare had shown them the helicopter still climbing. Its surprised occupant evidently had the large tube they saw at one side trained at a certain angle. To change it took time.

Don’s reverse maneuver sent them almost directly underneath the ship.

But there their wings were in danger.

Checking the ship, Don began the disconcerting, but very useful stunt termed a “falling leaf,” in which by alternately dropping one and then the opposite wing, the ship descended in a sort of zig-zag drop, much like the erratic course of a leaf falling from a tree.

Twelve hundred feet above the swamp, Don leveled, and with full-gun on sent the Dragonfly unerringly down-wind and straight at the runway approach lights a mile ahead.

They must get the mail in, he knew.

Swift, at its best, the craft sped toward its goal.

Don cut the gun, began the approach glide.

Far behind, unable to keep up, or, perhaps, giving up the chase, the Demon in the helicopter—human or otherwise—stayed aloft.

Down to the runway in a well-calculated glide Don swung his ship.

“Hooray!” exulted Chick. “Don—Garry—we win!”

The trucks leveled with the tail. The ship lost speed. Its wheels set their tires on the concrete and the ship, rumbling, ran forward.

Instantly Don cut the gun.

Mr. McLeod, the control room chief, and Doc Morgan ran up.

Garry tossed out the mail pouches.

“The ship-to-shore record is just tied!” cried McLeod. “Don—I owe you a lot for this—and your friends, too!”

“All right, Uncle!” Don swung about in his cockpit. “Doc—Mr. Vance—has anything been done about the Dart?”

“Why—ah—” Doc rubbed his chin as the older executive, with the control room chief at his side, raced for the waiting car in which the mail, still in its sacks, would be rushed to the New York Post Office, “yes, Don. They got a new prop set!”

“Good enough.”

“Why?” asked Garry.

Don had not loosened the chin strap of his helmet. He clambered hastily out of his cockpit, onto a wing, to the earth.

“Who’ll go with me?” he cried, as Garry and Chick came tumbling out of their places. “Garry—Chick! Which one?”

“Where? For what?” asked Garry.

“Back to the swamp—to find that Thing and make sure that it never molests any more pilots.”

“I will!” cried Chick.

“I will!” Garry’s words were shouted in the same instant.

“No! Only one can go in the two-place Dart!” said Don. “She’s all fueled up for the flight, you know, but there aren’t three places.” “But—” began Chick.

“I need one of you for ground work,” Don cried. “I have a plan! Two of us go aloft, fly back to the swamp. Maybe we can get there before the Thing has a chance to set down. Maybe we can fly around until we locate it. But somebody has to stay here in the control tower!”

“Why?” asked Garry.

Don spoke earnestly.

“Because—the control room chief took back a tracing, claiming he owned it—and because there was the beam of that searchlight on us tonight—and there isn’t another searchlight that I know of near!”

“Oh!” Garry saw light as Don spoke in his clipped, alert way.

“Yes!” Chick cried, “you think the control chief is working with the one in the helicopter—they are the ones who are trying to ruin your uncle.”

“Yes!” Don was already hurrying into the wide open hangar, where he saw several mechanicians adjusting the hub bolts on the small, swift Dart.

“But the chief of control has gone with your uncle!” Garry objected.

They were inside the hangar as Don answered, putting his words in low, swift earnest sentences.

“Only to the car. He’ll slip back here. We mustn’t leave him free to signal——”

“I’ll stay!” Chick declared. “I’ll stick to him as tight as his skin, Don. I’ll be a part of the Airlane Guard—and if he signals, I’ll be there—and we can get Doc——”

“No! Trust nobody!” Garry whispered. “Not even Doc! Don’t forget he was the one in the boathouse when you found the tracing.”

On swift feet Don raced away to the men completing adjustments on the propeller assembly.

“I’m taking the Dart aloft,” he said quickly. “Come on, Garry—run her out!”

In ten minutes, while Chick watched, and kept an eye on Doc and on the control chief, who stood watching in the hangar doorway, Don revved up the newly warmed engine, lifted the tailskid from the concrete, the chocks were dragged from under the wheels, and up from the runway leaped the Dart, with Garry, adjusting the Gossport, transferred from the other craft. They would scotch the Demon of the Swamps—or do their best to end his unexplained but menacing career.

Stars twinkled in the night sky as they roared straight for the haunt of mysteries. And the Demon was ready for them!

CHAPTER XV

THE DEMON’S LAIR

Straight and true Don sent the swift, light Dart to its mark.

Over the swamp they had last seen the helicopter.

In the half hour that had elapsed it could, of course, be far away. “But I don’t believe it is,” Garry murmured into his Gossport tube.

Don, listening, agreed with Garry’s surmise.

“Did you notice how that Thing looked while Chick’s flare burned?” Garry continued his conversation. “Under the big, bulky body, the helicopter had two things jutting out—I think they were pontoons. They have some sort of special bracing, and shock absorbers, so it can set down on land; but I am sure that the two projections were pontoons—and that, Don, tells us that the helicopter can get down on the water just as easily as a regulation amphibian.”

Don agreed as he watched the horizon line ahead.

“That Thing is human,” Garry added. “Ghosts don’t set off rockets.”

Once more Don was in full agreement.

They scanned the dark, silent sky around them and ahead of the nose as they approached, on swift wings, the scene of their recent struggle to escape annihilation and to get the mail in on time.

“Not a thing in sight!” Garry checked Don’s decision.

Where had the mystery ship gone?

As he asked the question, Garry removed the speaking tube from his lips and bent his eyes downward, over the cockpit cowling.

He searched the unrevealing water, grass and ooze of the swamp.

“Don!” his lips were again at the tube, “forward of the right wing, just where the fifth brace connects to the leading edge covering, I see a little light flickering. There—the wing is over it. Look! In a second it will be just at the trailing edge—there it is!”

Don saw the flicker.

As he started downward in a tight spiral, to keep close over the area and get lower, Garry spoke quickly.

“No, Don!” he objected. “Stay high, and go on away. Then we will climb higher and come back.”

Don took the ship out of the tight spiral, but turned his head inquiringly.

“It might be a lure!” Garry explained.

Don saw the logic of his chum’s reasoning: if the Demon, as he thought of that strange occupant of the helicopter, wished to draw them down into a trap, it—or he—would chose such a ruse.

Don, lifting the nose, soared away, climbing.

A mile away he banked around, and returned.

“There it is, again!” Garry, observing, indicated the flicker. It was more vivid than the intermittent glow of marsh gas which they saw in spots where rotted vegetation gave off its luminous aura.

“He is trying to lure us down, I’m sure,” Garry declared.

Adjusting the controls so that the ship, well-balanced, flew itself for a moment, Don scribbled a note, passing it to Garry.

“I don’t know,” Garry responded, reading and considering the communication. “It might be safe and it might not to go down. I know we can’t get anywhere flying around up here; but anybody as deadly as that Demon is dangerous to get close to.”

Don hesitated.

He wished to beard the deadly one in his lair, to come to close grips; he did not desire to risk Garry’s safety without his chum’s consent.

Nevertheless that was what he had asked for a volunteer to help him with.

Garry, he knew, was cautious, not cowardly. Therefore Don hesitated.

Once more Garry’s steady voice came to his ears.

“How about doing this?” Garry asked, “let’s fly away as though we hadn’t seen the lure, get over the airport, and signal by blinking the flying lights. The Demon can’t read them that far off, and we won’t be dropping flares to warn him. We can tell Chick we have located our ‘bad man’ and he can get your uncle, with the police, to surround the marsh. Then we can start sending over flares, go down, and guide the officers. They will catch the Demon if he runs, and, by closing in on all the paths, he can’t get away.”

Don agreed by switching the nose quickly in the proper direction.

Over the control tower they made a glide.

With the flying lights snapping on and off, Don spelt out a signal to Chick as he held the Dart in a tight, banked circle.

No response came, the control tower remained unresponsive. Its pilot signal beam, a small spot, did not flicker on and off to spell the “O. K.” Don expected from his watching chum.

Chick, as a matter of fact, was otherwise occupied.

“Let’s set down,” Garry suggested. “The Demon will probably wait, hoping we will go over again and see his lure. He must have meant us harm or he wouldn’t have set those rockets to strike the Dragonfly.”

Don, flashing the “must land” signal of distress with his blinking flying lights, got no response: he decided to risk approach without the signal, and finally tumbled out of the Dart with Garry already on the ground.

Leaving the Dart idling, slipping chocks under the wheels, Don and Garry hastened into the big main hangar.

It was empty, echoing, deserted.

So, too, they found the upper offices.

“There has been an awful ‘shindy’ in the designing department,” Garry whispered, training his finger, at the door, after flashing on the office lights. “Somebody has tried to break into the locked cabinets, and there is a wastebasket turned over and a chair upset. There must have been a fight in there.”

Don, looking, agreed.

“Come on!” he muttered, “something has happened here. Uncle is in New York, of course. He hasn’t had time to get back from delivering the mail we flew in. But where is the control room crew, and the hangar man, and Doc, and—Chick?”

Up the stairway, not replying, Garry followed him.

“Nobody in here!” Don turned a dismayed, and frightened, look on his chum, who responded with equal concern in his face.

“Something has happened,” whispered Garry.

At once he became practical.

“Don, we can’t stay here to find out what’s wrong. You want to capture the Demon. Run down and check your fuel, while I telephone the police station and report this—and ask for help on our ‘round-up.’”

Don raced back down the stairways.

Garry, rejoining him, a scant ten minutes later, was very sober.

“Chief wasn’t at the station,” he reported. “Man at desk seemed to be half asleep. Said the Chief had been called away on a special errand. Wouldn’t say how soon he could get help out here. There’s a mystery about all this, Don. What shall we do?”

“Run up and leave a note for Uncle,” Don counseled. “I’m filling the tank. If we can’t get help, we’ll handle this ourselves!”

“How?”

“I’ll go aloft, fly over the swamp, locate that area, and act as if I have discovered the lure for the first time, if it is still there.

“And I think the Demon is waiting, sure we’ll take his bait!” he added.

Garry scribbled an informing message for the airport owner, detailing their purpose, and what they had experienced and the condition of the airport. Then he rejoined Don, the chocks were removed, and as he stepped away, with a wave, Don, alone, sent the Dart aloft.

Hardly waiting to see the fleet raft begin its trip toward the scene of their many mysteries, Garry hurried down to the wharf and water runway, down which the land-and-water types of craft were sent from the hangar: to one side was a landing stage for passengers from seaplanes, and at the end of that lay tied the “crash boat,” a swift, electrically propelled cruising launch kept always ready in case of any mishaps to seaplanes or other craft over the bay.

To clamber in, unleash the swift craft, and swing it out from the wharf with its speedy, quiet motor humming a low, soft drone, was the work of a moment for Garry, whose assignment in an emergency was at the speed control of the “crash boat.”

The prow of the speedy vessel turned North, angling across the inlet to skirt the point of land he must turn to get to the swampy channels beyond.

Garry knew the channels quite well, and, in the darkness, with only a dim gleam showing from his small forward light, a double, red-and-green cruising lantern, he was able to scan the starry sky and, as he coursed along the shore, passing the mouths of inviting channels, to discern, quite low, and inland, the flying lights of Don’s ship.

Their plan was simple.

Don, cruising, in the air, would discover if that lure called him, tempted him to set down—perhaps to some dreadful fate.

Garry, in the silent-motored, and fast little “crash” launch, would follow the shore to a channel known as Crab Channel. Down its somewhat deep and broad course he could turn inland, coming closest to the scene of their mission.

Then, hidden from inland eyes by tall grass, he could use a strong flashlamp to signal to Don, who would be circling wide. If Don saw the signal, and thus knew that Garry was ready, he would put out his flying lights. Then, dropping low, he would circle over the area Garry must reach.

With his own motive power so quiet, Garry could locate easily the sharp, intermittent periods of noise as Don alternately fed full-gun and gunned down. The noise, they knew, and Don’s low altitude, would fully occupy the attention of their quarry.

Don would hold his tight circle, climbing a trifle, gliding, keeping his motor alternately full-gun and still. Garry, creeping in through the most available channel offshoot, could locate the object of the ruse and then, surprising him, set off a self-igniting flare, attack, and at least hold the Demon, victim of the surprise, until Don could set down and help make his capture certain.

Everything went smoothly. Garry gave his signal. Don’s low flying lights winked to blackness.

Over the swamp, two hundred feet up, he cruised back toward some hidden adversary, menacing, terrible, watchful.

Swiftly, silently, Garry’s light motor impelled the “crash” launch up a channel which, with his alert ears guiding him, brought him closer and closer to the dark spot wherein, from the water level, he saw a weird sight.

Floating on a still, shallow pool, supported by its queerly designed pontoons, the helicopter was hardly visible in the shadowy eel grass: its horizontal blades, tilted by some device to a vertical line, made only a thin, invisible angle to the sky, although Garry, from his lower point of vantage, saw the outline against a starry background.

Intermittently, from the cockpit, and thus concealed and throwing its beam upward only, came the periodic flickers of a handkerchief-wrapped flash torch.

Its intermittent, dim glow illuminated the almost shapeless form and backward-thrown head of the Thing that never was, the Man Who Never Lived.

Tide-drifted, flare in hand, Garry floated toward the Demon’s Lair.

CHAPTER XVI

CHICK TRACES THE TRACING

Seemingly unaware that Chick dogged his steps, the control room chief, whose initials, J. V., had proved the baffling tracing to be his property, went from the runways to his tower quarters.

Doc Morgan, following Chick, appeared at the door to the control room a minute after the youth had seated himself unobtrusively, in a chair in a dark corner.

“You might as well go home,” the control room chief dismissed his assistant who turned from an observation window where he had stood scanning the sky, and taking his hat, said “Goodnight.” His chief, paying no attention to Doc as the latter lounged in the doorway, walked to the windows and glanced in several directions towards the heavens.

Chick sat quite still. Doc knew he was there, he saw; but Doc was evidently interested in his own thoughts, and, beyond giving Chick a pleasant wink, ignored his presence.

Vance, the control chief, assured himself that there was no immediate need for his services for landing ships. He adjusted several switches to leave the essential lighting of approaches going against Don’s return, and then walked over to the radio table in one corner.

Chick, watching, saw that the man’s thoughts were far away from duty.

Watching unobtrusively, he saw Vance lean his head on the hand supported by an elbow on the table.

Doc, still lounging, seemed forgotten, and appeared to be satisfied.

“They are both thinking about the same thing. That’s my guess,” Chick told himself. “Doc had something to do with that tracing that turned up in a boathouse in the marsh, and Mr. Vance knows it. And Doc knows he knows it, too! I’ll sit tight and see what happens.”

He had no long vigil.

Apparently so deep in his thoughts that he forgot the others, Vance sat in a brown study for a moment: Chick, quick of eye, observed that the control chief was not so oblivious as he pretended.

“He’s watching Doc,” he decided.

The silence was broken by Doc’s amused voice.

“Well, J. V., go ahead and unlock the drawer. You want to, you do, and you know it, you do that! Well, go on. Do it! I’d like to know what that sketch means, I would. Let’s see it again, eh?”

With a start of surprise that Chick sensed as “acting,” the other looked around quickly.

“Oh! Hello! What’s that, Doc?”

“You heard me.”

“About the tracing, it was.”

“Yep.”

“Rats!” The man leaned back, arms behind his head, carelessly locking his fingers as he pretended to laugh. “Doc, you’re pretty interested in that, aren’t you? Considering where it was found——”

“Yes, considering where it was found—” Doc repeated the words with a meaning that differed from the other man’s phrase. “Considering that it was supposed to be a sketch of a new design for an airplane, and I saw our young friend, Chick, discover it when the wind yanked it out of a drawer—” he forgot his mannerism and spoke directly, crisply, “I wonder if you go over there to work on it in secret—eh?”

The man swung around in his chair.

“As likely as that you go there to hunt sea-marsh stuff for medicine,” he snapped. “It was stolen from me, as a matter of fact!” He turned his eyes on Doc, accusingly.

“Not by me, brother not by me, not it! No, sir! You got it back, anyhow, so what’s the odds how it went? What is it—besides a sketch of a new aircraft?”

Chick became more alert, more intent: he had to hold in check his impulse to hitch forward in his chair. The answer might be interesting.

The control chief laughed.

“Besides a drawing of an airplane—what could it be, I wonder?”

“Look here!” Doc left the doorsill that had supported him, and took a few steps closer to the other man.

“See here,” he repeated, “do you recollect when the engineers were draining the swamp, and found a skeleton of some poor old codger who was supposed to be one of the old pirate band that used to hang around New York, a good many dozen years ago?”

Chick started. A pirate! He recalled that the local newspapers had printed several lines of historical fact, hinting that the bones found in the swamp might have been a relic of days of piracy in the harbors and bays, the sea and the Sound, in and around Long Island and New York.

Suddenly something that had never before seemed of importance to him flashed across the youth’s agile mind.

Among the piratical names important in history of activity under the skull and cross-bones, none had stood out more than that of Morgan.

And before him stood a man whose name was “Doc” Morgan!

He suppressed his tendency to utter a cry of surprise at his discovery; his ears became even more intent as he held his voice and his quivering nerves in check.

“Oh, yes, I do recall something about the skeleton and piracy,” the control chief remarked, carelessly.

“Well, now, you do, do you? Is that so?” Doc’s tone was sarcastic. “Do you happen to recall that pirates used to sail in brigantines, and such-like ships? Yes, you do! Sure, you do! And there is a story to the effect that one time an old brigantine was throwed up onto the mud, it was, in a gale, off the very swamp where that skeleton was found!”

“You don’t say!”

“I do say!”

The control chief was obviously interested.

“How do you know?”

“Who would know better than a Morgan?”

Chick’s wriggle of excitement went unobserved.

“That’s so,” Vance remarked. “You are named the same as one of the old buccaneers, at that! Say, Doc—tell you the facts:

“I was with the engineers when they discovered that skeleton.”

“I knew it all the time. So was I.”

“Oh, yes—I recollect, you were,” Vance agreed, while Chick listened and tried to register in his memory every look, every phrase, every intonation of the two men. There was either a fresh mystery leaping to the fore, or the explanation of many mysteries was about to come into the light.

“Well—” Doc paused significantly.

Vance cried that he did not understand that hint.

“If you mean that anything was found, you know as well as I do that nothing was,” he finished.

“No,” Doc argued, coming closer, but no longer sarcastic. “No, Vance, nothing was found. But the finding of that skeleton, it brought out all that about the pirates, it did. Yes, sir, it did that! And what’s to say all the talk about the pirates didn’t show somebody—who—already—had a—map-or chart—that it meant something!”

“Let’s see it!”

Chick, forgetting the mission he was detailed to pursue, forgetting his former suspicions of Doc or of Vance, and intent only on that new topic—a mysterious, concealed map or chart, hidden among the intricate lines of a design supposed to be for an airplane, startled the two men by his exclamation.

Vance, wheeling, studied him a moment, evidently becoming satisfied that Chick’s interest was as purely on account of the new idea as was his own or that of Doc.

“Why, sure! You’ve seen it, already, anyhow,” the control chief conceded. “Tell the truth, you two, I can’t make any more of it than you did. The day that the skeleton was found, after you had all gone away, one of the engineers took me to one side, and said he had seen a queer thing when he was in the old boathouse trying to hire a dory, to get to the place where the skeleton had been discovered, and where all the excitement was centered. He had seen a half open drawer in the table there at the boathouse, and in it was a tracing paper, pretty old, and seeming to be of an airplane. It was so curious to see it there that he mentioned it and I took him in our power launch—the crash boat—to the scene of the excitement, and then cruised back to the boathouse for a look at that tracing. It was just what you’ve seen. Well, I sat there, all alone, studying it, but I couldn’t make anything out of it.”

He turned and began sorting keys on a bunch he drew from his trousers as he prepared to open the drawer of the radio table.

“At first I thought what Chick did when he first saw it. There was part of an aircraft series, stolen or mislaid and carried there by some visitor.”

“Then what did you think, afterward!” Chick asked eagerly.

“I wondered, but I didn’t actually decide much of anything,” Vance answered. “Well, you know how a fellow does when he’s absentminded, studying, or something—draws marks on paper!”

“Yes! I’ve seen you do that when you were in a brown study,” Chick agreed. “You draw—let’s see—J. V.”

“Exactly what I do!” Vance agreed. “Well, you two, believe it or not, while I sat there, thinking, I drew my initials on the table, and one set got on the corner of the tracing. I didn’t see how it mattered, and I meant to bring the thing here anyhow. So I let them stand.”

“But you left it there,” contended Doc, “left it, you did. Yet you claimed it, you did so, as yours!”

“Yes. I dropped it in the drawer when a hail came for me to bring the crash launch to help my boss. I wasn’t control chief then, only an engineer working out angles and distances across the swamp for the airport extension,” Vance declared. “I forgot all about the tracing until I read in the papers about the piracy and the hints about lost treasure and all that folderol. Then, when Chick so kindly brought in the tracing, I recollected my initials—and there you are.”

Chick reserved his opinion about the truth and reasonableness of the explanation. Certainly it was a point in Vance’s favor that he was already willingly slipping a key into the table drawer.

“Why!—look here!” Vance cried, “this drawer isn’t—locked!”

He dragged it open. At once Chick knew, just as he saw that Doc realized, that the tracing was gone.

Had Vance made up all that story? Had someone picked the lock? Was that queerly disguised tracery of lines more than an airplane design? Who had it?

Chick took no time to puzzle out answers.

“Never mind, for now!” he exclaimed. “I wasn’t such a dummy, after all. While I had that tracing, before it got lost again I decided to make a blue-print of it. I did, too!”

“Good!” exclaimed Vance, and Doc nodded. “Get it!” he urged.

Chick ran down the tower stairs. At their lower steps he stopped, stricken by an uneasy realization that he had completely shirked the duties laid on him by Don. He was not guarding that tower, not seeing what Vance did, not heeding Doc.

Thirteen years—piracy—mysterious maps—hidden meanings—possibly buried treasure—the combination had been too much for Chick.

Should he go back, or go on and get the blue-print?

“I’d better go back,” he said. “I can get the blue-print when the rest are here. Maybe Vance made all that up, and took advantage of what I said, just to get me off the scent, to stop me thinking about watching him. I’ll go back.”

He turned to ascend.

From the hangars came the crash of an overturned chair, or some such odd sound. On the office floor it seemed to be to Chick.

Furiously racing along the corridor, he watched for opened doors, in the faint light of the corridor bulb at the landing.

The design room door stood ajar!

There he swung in, catching the jamb with a hand to expedite his turn as he reached the opening.

Inside all was dark, still.

“Who’s there?” he called, and listening, heard no sound.

His fingers found the light switch. The room sprang into brightness.

“There’s a chair upset,” Chick called out. “I know you’re in here. Come out!”

Silence met his demand.

With quiet feet he advanced, past an overturned wastebasket, past the filing cabinets. They had been tampered with—he saw that as he passed.

In a corner was a wash basin, marble, on a stand, and before it was a Japanese screen to conceal those who chose to wash.

Tiptoeing, Chick advanced close to the screen.

Unexpectedly it was thrust over onto him. He had half expected the maneuver, and he leaped sidewise and backward, just escaping the edge of the light frame and the entangling silk stretched over it.

A tall, thin, dark-haired, reddish, copper-colored youth leaped past him. Caught off balance, it took Chick half a second to right himself. Then he was in pursuit, screaming as he ran. The other was fleeter, longer-legged. He seemed to have prepared a plan. Chick heard feet on the tower stairway, thudding down to his summons. They might intercept the escaping youth—an Indian, Chick felt assured at that. He was the faster of the pair, and Chick, for all his best effort, could not get a grip on the flying coat.

The Indian swerved, in the hall, into an office. Chick thought he had him cornered until the slam of intervening doors told that his adversary of the design room screen episode was out through the intersecting office suite, and had beaten him.

Chick ran to the fire escape at a window.

Down its iron rungs he went swiftly.

A figure, running lightly, crossed the hangar apron of cement, got to a car. Chick, putting every ounce of energy into his effort, ran, after a leap from the fire escape ladder, to try and reach the car.

“This way—he’s going away in a car!” Chick shouted, to guide the men from the control room.

Then he saved his breath, his task being to get to the car before the youth could get in. It was a light, cheap make of sedan.

Something Garry had told him seemed to come uppermost in Chick’s mind, some recollection; but he was too excited to pause and make sense of it.

The motor roared, gears ground into mesh, the car started.

Chick’s clutching fingers barely missed the rear tire.

He fell, carried forward by his leap, and lay, prostrate.

Then he lifted his head as the car roared away, and when Doc Morgan and Vance reached him, he sat up, smiling.

“Let’s take my car!” cried Vance. “Come on, Chick. Doc, stay and take care of the place. Get my assistant back to the control room!”

“Yes!” urged Chick, running toward the control chief’s bigger, faster roadster, “I remember something. Garry was taken to an Indian camp in that very car, and the very fellow who’s getting away with blue-prints or tracing is the Indian’s son who drove Garry back. I know the license, too. Come on!”

CHAPTER XVII

AN AERIAL CAPTURE

Flying low, as though trying to account for the mysteriously twinkling glow from the helicopter, Don watched carefully.

“There’s the crash boat,” he murmured, as his sharp eyes made out the dark object against the sheen of the still water in a channel.

“I’ll ‘give it the gun,’ now,” he decided. “The noise will drown out Garry’s motor hum.”

He opened his throttle.

Necessarily he drew further away. That suited their plan perfectly: it gave him distance in which to turn for his approach in a position to come down in a power-stall that would keep the engine running just fast enough to let the Dart settle onto the water without too much forward speed.

Garry’s hand was on the switch of the stopped electric motor: in the other he held his self-igniting flare.

“The tide will drift me around that clump of eel grass,” he told himself, “then——”

Don, as he saw, was banking around.

“Now!” Garry decided that the time was at hand.

Don was coming in.

The switch was thrown. The engine hummed, and forward drove the fast launch.

Above the swamp Don began his approach.

Surprised by the sudden illumination as Garry’s flare lighted up the small expanse of water where the helicopter lay, the Thing in the disguising oilskins and rubber face mask and cap and gloves turned to strain eyes through small cut holes.

Gathering speed the boat came toward his aerial chariot.

With a yell that seemed to combine anger and dismay the Demon swung to the momentum starter of his motor, sent its disk around feverishly.

Garry’s boat swept alongside, the switch on and gears in reverse to drag it to a stop.

Don, flying in, kept his engine droning, settling toward the water.

It seemed to both Don and Garry that their “Demon” was all but a prisoner.

Garry cut out the switch, allowing the boat to drive close.

“Give up!” he shouted, to be heard above the noise of Don’s approach from the air. “We’ve got you.”

The disguised creature gave a shout of defiance, threw his gears for the revolution that would wake the helicopter engine to life.

“It’s no use!” Garry cried, as Don, perceiving the slow turn of the helicopter’s upper blades as they were rapidly adjusted, lifted the nose and, instead of coming onto the water, stayed aloft, waiting, ready to frustrate any effort to climb away.

Garry’s hand clutched the pontoon braces.

Up he leaped, clinging.

Don saw, in the vivid light, the unexpected thing that happened.

Into the water, on the far side of the helicopter, away from Garry, plunged the queer creature.

Immediately Don cut his power again and dropped the nose; but he had to bank around to get in position once more to power-stall down.

Watching as he executed the maneuver, he saw Garry jump away from his position, half on the helicopter pontoon and half in the boat, turn as he sprang through the air, and strike water, with a flash of lighted spray, to begin swimming with strong, swift strokes, around the end of a pontoon.

Don lost valuable seconds, getting in approach position.

When next he could look, he saw that Garry was at the edge of the heavier concealing clumps of eel grass, treading water, hesitating.

Down came the Dart.

As he took the water Don cut out his power instantly, to enable him to be heard.

“Garry!” he called, “where is he!”

“Hiding in the grass, I guess!”

“Wait!” Don knew that Garry could make no progress trying to swim into that clutching, restraining mesh of tangled grass blades, tall, yielding, but gripping arms and legs in any effort to pass through. “I will get in the crash boat: he’s hiding. The boat will show him—it has a spotlight!”

Garry, treading water, listened for sounds of movement in the clump of grass, agreed.

“You’re captured!” he shouted to the invisible creature. “You might as well give up and save trouble.”

No answer came.

Don saw that the electric-powered boat was almost within reach as he hurriedly unclasped his safety belt, clambered onto a brace of his lightly rocking aircraft, and stretching out his arm, caught hold of the motor boat’s gunwale.

Quickly he got in.

To throw in the switch, and to light the small, but strong, spotlamp in the bow was the work of but a second.

The ray probed across the water, picked out Garry, treading water, close to the grass where he had seen his quarry vanish.

Picking up momentum to the hum of its motor, the vessel under Don’s steermanship moved to a point where Garry could catch its coaming, and draw himself in.

As he deposited his wet body in the bottom, Don backed water, in a slow, curving course, so that the small craft was ready, when he cut out the gears, to be flung forward, with turning room, in any direction he chose. His hand, on the light, swung its beam to and fro, sending scattering, filtered rays through the grass.

“I didn’t hear him move away!” Garry was up and at the bow with Don as he spoke.

“He must be just within the clump of grass.” Don drew closer, at very low speed.

“Listen!” Garry gripped Don’s arm. “Did you hear a shout?”

“Yes! Far away!”

They were distracted, for an instant, from the quest by the new and unexpected call coming from a distant point.

“Do you suppose it could be help—for us?” Garry wondered. “Maybe Chick left the airport to get police aid.”

“Let’s wait a bit and see if the shout comes again!” Don suggested. “This fellow we’re after can’t go far in that grass; he’d sink into a mudhole.”

“Maybe he did, already,” Garry hinted. “Maybe he went down and got caught in the grass.”

“That would account for us not seeing—”

“There’s the call—closer, too!”

They made out the words.

“Sounds like Chick’s voice,” Garry whispered. He called, high and sharp, “Stop!”

“Yes—and there’s a man’s shout—hear him?”

“I’m sure it’s help!” exclaimed Garry.

“But who can they be after?”

“They’re coming closer!”

A movement of the grass caught Don’s attention.

“There’s—” he began.

“No! Listen!” Garry put a hand on his arm, stopping his sentence.

Somewhere not far off, but to the right, inland, the grass clusters seemed to be agitated for a moment.

Don swung the boat, backing to get room, to be ready for the new position of their hidden adversary.

The light swung and focused.

“See anything, Garry? I don’t!”

“No, Don—and I’m sorry you backed the way you did. The helicopter is between us and the place I saw that fellow disappear——”

“But——”

From a point a hundred yards away came a hail

“Hello! You! Showing a light—who are you?”

“Don and Garry—Don McLeod at the helm of the airport crash boat, trying to catch the fellow who has been haunting the swamps and the air.”

“Don—Garry!” Chick’s shrill, excited voice floated to them. “It’s Chick and the control chief! We’re after an Ind——”

The sudden roar of the helicopter engine drowned the last syllable.

Don, reaching for the switch, with the other hand swung his spot beam but it would not swivel far enough to pick out the helicopter’s body.

“I hear somebody in the water!” gasped Garry, “Swing—forward, and swing, Don!”

The launch, in its position facing the left bank of the weed and grass-choked channel, made a difficulty of the forward swing, going too close to the grass. Its propeller caught in the grass or mud.

Instantly Don cut the ignition to avoid losing his propeller.

Garry fled to the stern, bent far, reached down, began disentangling the snagged part.

“Get him!” screeched Garry, to Chick as the light showed him on the bank of a portion of the more solid swamp land at the edge of which the channel ended, far across the sheet of clear water.

From the helicopter there seemed to come a surprised cry, and the sounds of an altercation. There was a splash—but the helicopter went upward!

Don, as the propeller was cleared and Garry shouted that news, did not try to pick up forward speed again. Instead he gave the motor its current with gears in reverse, and backed down toward his own Dart.

“What are you doing that for?”

“Going to the Dart.”

“But the engine is dead.”

“It’s still warm,” Don retorted. “I’m going to bring down that Demon.”

Chick, shouting, appeared at the end of a path, with the control chief, and guided by Doc, who knew the swamp trails.

“There’s somebody swimming!” he screamed.

Don paid no attention.

“Watch him!” he called, and then, as the launch came close to the Dart, caught a wing and clambered into the cockpit.

Garry, who took the wheel, ran forward again until he could revolve the small, fast airplane’s propeller: as his yell was answered by Don’s “contact!” he swerved aside, saw the huge blades begin to swing, heard the roar of the engine, and hastened to get his launch out of the path of the oncoming Dart.

Swiftly gathering speed, with sharp spurts of the gun to clear his choked cylinders, Don lifted his speedy ship into the air, soaring over Garry’s head as the latter, nosing in at the path end, took on Chick.

Up went Don, climbing in as speedy and steep a banked ascent as he dared with a recently stopped power plant to consider. He dared not force the engine until it was again at fullest, safest operating temperature.

The helicopter, rising almost straight up, had an advantage. But Don did not let that concern him. His teeth were tight, clenched, with determination wrinkling his eye-corners.

The Demon had gone too far. Evidently he had meant to lure them in the airplane, only to “finish them off” in some fashion. Garry’s unexpected appearance in the launch had upset those purposes. The Demon, taking advantage of the new chase, getting back to his craft, meant to escape, to lie hidden somewhere, ready to visit more of his menacing attacks on innocent folk.

“Not if I can keep my head,” Don muttered.

Swinging in his ever-ascending circles, spiraling, reversing to avoid that irksome sameness of turn which might make him dizzy, he kept going higher.

He knew that once he got near the ceiling, that highest point to which an engine can carry an airplane, he would be on equal terms with the Demon, because he could fly past, or execute some other maneuver, by which his propeller blast would upset control of those large top blades, cause the other ship to drop, whereupon, above it, and ever alert to guard against more deadly rockets from the improvised “gun” he saw on the ship’s side, Don could drive down his foe.

To his surprise, before he reached the ceiling, he came level with the other ship.

He saw the pilot, in the moonlight, lift a hand. Instinctively Don prepared to execute some dodging stunt; but all that was released was a white flare.

And in its light Don saw the pilot elevating both hands.

It was the gesture of surrender!

Tamely enough the other allowed his ship to settle. Like a shepherd dog circling a flock, Don went down above the other.

When the swamp was once more close beneath them Don saw that flares were burning, that torches were lighted in various parts of the land beside the Demon’s lair.

Hardly had the pontoons of the helicopter plunged into the water before Don had made his approach, easily guided by the vivid light.

As he swung down, contacting the sheet of water, Don saw, with surprise, that his adversary was no oilskin-cloaked miscreant.

The youth stepping from the helicopter into the electric launch was coppery of skin, black of hair. No other occupied the cockpit.

The launch turned, while Chick and Garry busied themselves with rope, binding the sullen son of Ti-O-Ga, the Indian Garry had met.

“Well,” Vance, the control chief, saluted Don. “You’ve brought down your prisoner. Wish we could say as much.”

“What happened?” Don asked.

As his engine died he listened intently.

“When this Indian ran away from the airport and came here,” Chick explained, “he must have tried to use the helicopter to get away in. But the real Demon jumped out as he got in, letting you go up after the helicopter while he got away.”

“But how could he get away?” Don remonstrated. “There’s only the narrow rim of land, beyond us, on Crab Channel, then another water inlet.”

“Mr. Vance guarded the paths,” Chick admitted, “and Garry picked me up and we beat the grass. I don’t know how he could get away—but he is gone—and with the police to help us beat this part of the swamp—all we’ve found is—just nothing!”

“But he—couldn’t get away!” expostulated Don.

“Couldn’t he?” said Garry, ruefully. “Well, then—where shall we look next?”

But Don did not hit upon the right answer.

CHAPTER XVIII

A CONFESSION AND THE CHARM

All that night they remained on guard. Taking turns, first Don in the helicopter and Garry on the shore, then the control chief replacing Garry and Chick taking Don’s station, they watched.

Not a thing happened.

The Indian, sullen, refused to talk.

Threats did not seem to disturb him. Pleas failed to move him. He realized that they had no way to enforce the threats. None of them dared to leave the swamps by the paths, taking him as a prisoner, because it had been his own familiarity with swamp trails that had led them safely through, although he refused to say why or how he had become so well informed. Besides, as Don argued, they dared not leave the swamp unguarded.

However, they kept a close watch toward the airport. Don’s surmise that his uncle would return from delivering the mail, find their note and institute a search, proved to be correct. Their flares being all used up in landings, however, they had no way to signal, and evidently the airport manager, deprived of Scott’s services, had no pilot to send aloft as a scout.

Early, just after dawn, however, he arrived, in a rowboat, at the mouth of Crab Channel, where Garry had driven the electric launch on his way to summon aid.

“Hello!” shouted the older man, laying on his oars until the launch came up and took him in tow, “I’ve had the chief of police and his men busy all night, trying to get reports of any crack-up, and scouting; but they must not have come to the lower end of the swamp at all.”

He caught a rope flung by Garry who towed his rowboat up to the scene of their all-night vigil.

Practical, a little sarcastic, Mr. McLeod took charge.

“I don’t suppose it occurred to any of you that the fellow you tell about had to get here somehow, and to get away,” he said. “Daylight makes it clear—see those stakes with the rope?—that the helicopter has been kept here a long time. It didn’t occur to you that the fellow in disguise might have come here in a dory—and left by the same means!”

“No, it didn’t!” admitted Don.

“Well, boys, that’s what happened.” The airport executive pointed to the grass, stamped and bent down, and when they asserted that their own searching had accomplished the tell-tale destruction he smiled, led them past the clusters near the boats, further inshore, showing that grass had been pushed aside, tangled by the passage of a body, and then indicated a smaller, shallower, but practical waterway, diverging toward the South.

“Here are marks of a dory’s nose on the mud,” he explained. “You have been watching for a man who calmly sculled or drifted away.”

“But we couldn’t see that at night,” objected Chick, “any more than we could see the paths out of the swamps. Now, I can, though—and I’m for getting to a telephone, calling the chief of police, and letting him send a man here to see about putting this Indian in a cell.”

The Indian, not much over nineteen, became more talkative when this purpose was mentioned.

“I haven’t done anything really wrong!” he declared. His English, like his clothing, was good, showing education and refinement of a sort.

“A year ago,” he said, revealing his identity as the son of Ti-O-Ga, and named simply John Tioga, “a year ago a film company came up to our place to make some films dealing with Indian witchcraft and dances, for the prologue of a picture. Father played the old ‘medicine man’ and I was a sort of magician-devil in the picture.”

“I don’t see what that has to do with this,” began Chick.

“It has,” the Indian youth assured him, sullenly, “because that picture has been released and shown around, and Father and I have made a good sum of money, doing what theatrical people call ‘personal appearances,’ and showing some magical tricks, as a prologue to the film showing at different theatres.”

He explained the connection between that and the present situation.

“A man has a picture theatre here in your nearest town,” he told them. “His name is Toby Tew, and he came up to our place about two months ago to engage us for a personal appearance when he shows the picture. We had been disgusted with the sort of people we met in the theatres, because they were rough and ready, not bad, but not especially refined——”

Don smiled, thinking of such a statement coming from the race which had tomahawked and scalped in pioneer days; but reconsideration made him realize that the pioneers had slain also, and had introduced not only “fire water” but had taken away lands the Indians felt were theirs. Again, he reflected, the Indian of culture, with a college education, was far away from his savage ancestors.

“We refused to come here to ‘play’ our special magical show,” the Indian went on, “but it wasn’t long after that before another man from these parts came up to the Catskills—but he wanted to consult my father about some hidden or lost object—or—er—things!”

“Who was he?” demanded Don.

“Called himself Morgan—let’s see——”

“‘Doc’ Morgan?” inquired Mr. McLeod.

That was the name, the youth acknowledged. “What had he lost? What did he want to find? And how could your father help him locate anything?” asked Garry, quietly.

“You ought to remember what my father did with you,” the youth challenged. “Father knows a great deal about hidden forces of the mind and of Nature. Sometimes, if his mood is right, he can do what fortune tellers would call ‘divining’—read the future, or locate articles that have been hidden or mislaid. Whether he puts two-and-two together or really can see deeper than others, I won’t argue with you; but he does get results. Doc Morgan wanted him to help him locate a lost ship, said to have been buried in mud in this swamp——”

“Oh—I see how everything begins to fit in!” cried Garry. “Somebody had a map, or chart, or plan of some ship supposed to be in this swamp. Well, then, Doc heard about the skeleton being found—or saw it found! He read the news hints about the possible treasure buried here.”

“Yes—and he either found the tracing or saw it!” agreed Don. “Then he went to the ‘medicine man,’ because he told us that your father had taught him all he knew about herb medicines, John.”

Nodding, the Indian added:

“But he wanted us to divine where the ship was buried, and we did our best. Then—when the two young gentlemen here—” he indicated Don and Garry—“came there, with their injured pilot, and Father learned by putting two-and-two together—or however you choose to say he did—that there was a stolen tracing of a ship, we took the contract your theatre man had offered, and I came on ahead a week ago to look over the ground and see what was what.”

“And what was ‘what?’” demanded Chick.

“I can’t give you that answer,” the youth declared. “I’ve trailed the tracing, but some one took it before I could get a chance to see it. I was hiding, listening and watching, in the airport, this evening—or last night, to be correct. I heard it said that the map was gone, and I ran and hid, but the young man you call Chick discovered me. I was so afraid I’d be accused of theft of the tracing I’d never seen that I lost my head and ran—and when I was chased, and saw something in a disguise going to start into the air in a helicopter, I swam to it and went up—and you know the rest.”

“All but this!” Don said. “You were close to that fellow in the disguise. You were in the helicopter with him——”

“Only for a minute!” interrupted the Indian youth, then he checked himself, as though a sudden idea had occurred to him.

“What has struck you?” demanded the control chief.

“I—” the youth hesitated, while Don, Chick and Garry listened with a feeling that they were about to hear a revelation.

“Go on,” Don prompted.

“The—er—Thing was tall.”

“Yes!” Chick broke in as Garry opened his lips to speak.

“Well, he can fly. It made me think of another tall man who could fly—and who came to consult my father when he happened to be away from home. He said he was a mail pilot, and he gave the name——”

“What?” cried Chick.

“Smith!”

“Oh!” Garry recognized the flyer mentioned. “He flies the mail in from Philadelphia. But——”

“It couldn’t have been Smith who tried to run us down, tonight,” Chick remonstrated. “He’s due later on, coming in from Philly. He goes down Friday and comes back Saturday—and last night was Friday night.”

“He comes in tonight—so he can be left out—unless he had a substitute fly for him last night,” said Don, suddenly wondering.

They discussed it but made no progress beyond deciding to investigate the whereabouts of the mail flyer.

“Anyway,” the Indian said, “you should remember that my father gave you a charm that would prevent any harm coming to you.”

“That’s so!” said Chick. “Garry has been wearing it, all week.”

He stared at the chum he had spoken about.

Garry’s face was wreathed in a queer expression, half surprised, half eager.

“Golly-glory-gracious!” he exclaimed, “I—had forgotten.”

He had.

“Do you know?—” he turned to Don.

“What morning is this?” he inquired, with a grin.

“Saturday,” Chick responded for Don.

“Yes—and what was last night?”

“Friday night, of course, silly!”

But Garry grinned more widely. The others wondered, but waited.

“What has happened on four successive Friday nights, around Mystery Airport?” he demanded.

“The spook has appeared,” Chick volunteered.

Garry nodded.

“And what did I get to guard us against spooks?”

They remembered the small bag John’s Indian father had called a “charm” to clip ghost wings.

“What was I to do with it?” asked Garry, excitedly.

“You were to wear it all the time—let’s see—for seven days!”

As he spoke, Don caught his breath.

“Wear it for seven days—and then open it!” he cried. “And this is the seventh day—or last night was the seventh night after our flight!”

Nodding, Garry produced the bag from his shirt, breaking the small cord it was attached around his neck by.

“Now, let’s see—” he began, and tore loose the wax-sealed neck.

They craned closer as he peered inside. His face dropped, then he discovered something. Eagerly he extracted from the bag three yellow oblongs of thin, printed paper.

“What in the world?” he cried.

“I’ll say!” Chick stared. “A charm to clip ghost wings. Three—free—passes—for—the—Palace—Theatre!”

The Indian youth smiled slightly.

“My father is a clever man!” he remarked.

CHAPTER XIX

A CLUE IN SMOKE

After a somewhat disappointed study of the three yellow picture theatre passes, Garry turned to the Indian youth.

“John,” asked Garry, “what do these mean? There isn’t anything on them but printing. They say, ‘Admit bearer’ and give the Palace name and they are signed by the theatre manager. But there isn’t any help there, unless something is written on the backs in disappearing ink.”

“Maybe, if we heated them, or wet them, something would come out,” suggested Chick hopefully, “as they stand, they are just three passes.”

John, with a quiet smile on his copper-colored face, replied curtly:

“My father is a clever man. He put this with that, and know much. You try doing that.”

“Personally,” Mr. McLeod was a trifle sceptical, “I think they are part of the plot to confuse you and the rest of us. No doubt the old ‘medicine man’ is clever—clever enough to be involved in some way and to try to pretend that he is a helpful chap when his whole attention is to throw out a smoke screen to protect himself and—” he frowned at the young Indian, “—his son.”

Garry put them back in the skin bag, slipped it into his pocket and switched in the current to back the launch around.

“You might try using those passes,” the control chief suggested, as the boat moved down the channel.

Garry nodded.

“We will,” he agreed.

With the ignition key and a carburetor needle and float removed, the helicopter, tied once more to its stakes, was in no danger of being removed. They felt that they could safely leave it: no one would be able to use it with parts so vital missing. If the owner had a spare switch key, it was totally unlikely that the carburetor parts were duplicated.

Don’s plan, quietly communicated to his two friends and to Mr. McLeod, was to be tried.

They would leave the disabled helicopter as it was, go back to their daily tasks in the designing department of the aircraft plant and the airport, and keep a watch on the control chief, on Doc Morgan, and on the swamp, from the control tower balcony, with strong binoculars.

No garage, accessory store or hardware shop could replace the special carburetor parts for some time; after instructing their own shop foreman to report any application for the parts that might be made to him, Don rode in to Port Washington with his uncle and visited every shop, garage and other place where such things were available, told enough to enlist attention, without disclosing any of their suspicions about the tracing and its possible meaning, and secured a promise to have a report made of any request for carburetor floats and valves of the unusual type they had looked up in the catalogues.

“Now,” remarked Don, as their sedan returned to the airport, “if any spook, or man who calls himself a thing that never was, comes around to put his helicopter into commission, we can grab him, for we will know that no one else would be after floats like the one we removed.”

His uncle nodded, morose and uncommunicative.

Rejoining his chums, Don explained his recent activities.

“I found that the blue-print files had the lock picked,” Chick told him, “and the blue-print I made of the sketch was gone.”

“I’ve just come down from the tower balcony,” added Garry. “The helicopter hasn’t moved. I just barely made out the blades above the grass. The way they are kept when it isn’t being used, the blades are sideways to the line of sight from the control tower. That’s why none of us, especially since we weren’t looking for it, ever saw the thing.”

“Probably Mister Spectre-Man had it there all during the haunting time,” Chick remarked.

“But what did he use it for—and how did he use it?” objected Don. “The spooky airplanes were biplanes, old-timers, and there never was a helicopter in sight.”

“I suppose he used it to get to his other ships, and then flew them between a cloud and a light, so the shadows appeared, just as the shadow of your Dart showed to us the first night we tried being Airlane Guards,” Garry suggested.

“But why should he hide it in the swamp, and need it at all? If he had a biplane, he could take-off from miles away,” Chick argued.

“It’s as much of a puzzle as that mixed-up affair of a chart that may be an airplane design, or a camouflaged drawing of a privateer or old-fashioned brigantine that has treasure hidden in it,” Chick mused. “Now, we’d better get to our watching. Doc is my assignment. He’s eating breakfast, so I’ll go and get some, too.”

“Control Chief Vance has gone to bed,” Garry said. “I won’t have very hard work keeping track of the cottage he lives in, from the platform where I watch the helicopter. Don, you’ll be free, then.”

“Well, I’ll work on the inking in of the new tracings,” the young pilot decided. “Wouldn’t it be odd if my study of airplane design had some good effect in clearing up our mysteries?”

“It certainly would!” agreed Chick, moving away.

While he used square and compass, drawing pen and India ink, making the perfect outlines and shading on tracing paper which perfected the multitude of parts’ designs, before the working blue-prints were made by Chick and Garry, Don kept that idea in the back of his head.

It would be fine, he mused, to be able to use the knowledge he had gained, especially about airplane construction and the creation of the original plans for new models, to solve the puzzling, baffling set of unexplained circumstances.

The possibility seemed far-fetched, though.

“How can it help that I know about streamlining the body, and the struts, and even the flying wires?” he asked himself, “or what can I make of wing-taper, and camber, and all that?”

He completed the application of India ink to the drawing of a seaplane body, in outline, showing the many braces and their points of attachment to the longitudinal “keel.”

He put it away, with others, in a folder when it was dry.

“I guess knowing about designs won’t help, any more than knowing how to fly a ship was of any use to the Airlane Guard,” he murmured, laying the folder aside for Garry’s later use.

“If we only had the ‘ignition key’ so we could make ‘contact,’” he smiled at his application of aviation terms to their puzzle, “it would be easy to give it the gun and fly a straight course to the solutions.”

When dusk came on and the chums gathered to compare notes, the day proved to have yielded blanks all around.

“The Indian told the truth,” Garry reported. “Your uncle has engaged a private detective and he checked up. John and old Ti-O-Ga are ‘playing a split week’ engagement at the Palace, starting Saturday—today. The helicopter hasn’t been moved. A private detective is there, watching it, and one is in the hangars.”

“We can go to the movies, then,” suggested Don. “Let’s see if the old ‘medicine man’ meant anything by giving us passes, and telling us to take them out of the bag after seven days.”

“He might, at that,” Garry became more animated. “That connects up, because after seven days he knew he would be here, with his son.”

“I hadn’t seen it that way,” responded Don. “Let’s go!”

They found the Palace, on a side street, fairly filled when they presented the three yellow slips to the door man. Large “cut-out” figures of Indians, in various poses, and posters, from “one-sheets” to “flash twenty-four sheets,” decorated the theatre and billboards nearby, showing in blatant coloring the scenes from “Red Blood and Blue.”

The doorman, to whom the chums were well and favorably known, chuckled as he accepted the “dead-head” tickets.

“Papering the house, eh!” he chaffed, referring to the method by which, issuing free tickets, a manager sometimes made it appear that his theatre was well patronized. “Well, you won’t like the show.”

“Why?” Chick demanded.

“It’s the old story that the fellow who comes in free does all the ‘knocking,’” responded the doorman, “I ought not to let you in at all, by rights. Passes aren’t good on busy week-end nights; but these are good any time—specials from the boss. How’d you get them?”

“In the most ‘charming’ way you could think of,” Garry made a hidden reference to the Indian’s “magic bag.” “They were ‘gave’ to us.”

“All right. Go on!”

In they went, finding a trio of seats about the center of the small and rather old-fashioned theatre.

A comedy was just reaching its end, and the jet silhouettes of a fantastic kitten, gyrating across the screen from a kick, punctuated their arrival with a gale of laughter from the audience.

They were just in time for the “presentation,” preceding the main attraction.

The heavy draperies of the softly lighted curtain swung down, concealing the stage until the screen was taken away.

Softly the small orchestra began a weird musical number, while from the projectors that threw the pictures onto the screen, their lenses showing colored lights instead through tinted isinglass disks, came a combined rose and blue that gave the stage, as the curtains opened, the effect of dusk coming on just after sunset.

Weird tom-toms thudded gently from the enclosure which pictured a forest background. Before this, around a small “practical” fire, well protected, sat some supers, made up as Indians.

“There’s John Ti,” murmured Chick to Garry.

“He’s going to sing!”

As Garry spoke the young Indian broke into a chant, with a melodious voice, standing against the soft light supposed to be the dying sun’s afterglow over the sea, to one side of the stage.

Three white people came into the scene, watching, all evidently campers, from their dress. They were extremely modern, both in pantomimic actions and in their garments. One was a girl, the other two were men, and their attentions to the girl spoke clearly of great interest in her.

To the increasing rapidity of the music after the song, those make-believe warriors seemed to be caught by the spirit of some old mood, and they rose, moving about, presenting a colorful, barbaric picture as they began a dance, to the thrum of the piano and the song of violins, while dull drumbeats punctuated the music.

From the wings, as the music became more wild, appeared the old Indian in blanket, feathered head-dress and other marks of his chieftainship.

One of the men began to make motions calculated to show his feeling of superiority toward the stalking old man, and the girl turned from him in a sort of distress, then the other man caught her hand, whereupon his rival glowered, and his hand moved toward his hip.

At once the old chief stretched out an arm—the dancers drew back and squatted, the chief approached the fire, beckoning to the girl.

She approached slowly, fearfully, and the music became low as the chief, squatting, drew out a bag, extracted from it some herbs which he threw into the fire.

At once a great pillar of whitish, dense smoke rose, straight upward toward the wings.

“Clever, isn’t it?” whispered Garry. “They must have a fan under the trapdoor of the stage, just below that fire, to make those flames leap and the smoke go straight up.”

“It makes me feel sort of creepy, and as if it was real!” Chick responded. Then they watched, in surprise.

In that white, thick, ascending pillar of smoke, as though on a screen, there slowly appeared a vision!

There was the girl. There were two men. But they were Indians.

A quick pantomime in the moiling, upcurling smudge revealed hatred between the men, and fury when the girl chose the rival.

Into that vision blended another so that as one vanished the other was visible. It showed the two men, again with the girl, but as they actually stood on the stage, almost the same in appearance, as near as the men engaged by the theatre could be matched to the vision.

That picture of hatred was again enacted in the new garb, and the vision was once more displaced by another—and the chums gasped.

In that smoke column, black against white, two biplanes flew one after the other toward the audience—they seemed to merge, to blend, to vanish, and then—as Chick made an involuntary little scream of amazement—the smoke was filled by the vision of two black, bi-winged shapes coming together.

The drone of their arrival filled the theatre: so realistic was the effect that the planned scream of the girl on the stage was echoed by women among the watchers—to the rumble and roar was added the culminating contact.

The vision died as the translucent screen through which it had all been observed was gradually lighted by the first scenes of the real picture, showing the events of the story which began at the crash.

“Well!” muttered Don, “did you see what I saw?”

“The very same as the spectre in the cloud!” agreed Garry.

“Yes,” Chick contributed, “and I see the clue in the smoke, fellows. Every time that spook has appeared—it has been a cloudy night!”

“That’s it!” Don agreed. “The cloud acted as a screen—and now we know what was done—a picture was thrown on a cloud. But how—and by whom?” He paused. The theatre manager, passing up the aisle, gave them a pleasant salute—and all three mentally answered Don’s query!

CHAPTER XX

DON TESTS A THEORY

With one accord the trio of youths hurried out of the Palace and paused just around the corner from its lighted marquee.

“Yes, sirree!” Chick spoke the conclusion of a train of thought that was clear to his comrades, “Toby Tew is the one!” Don nodded.

“He knew about that film they used,” he declared, “and how the picture was thrown onto the smoke. They had a picture projecting machine hidden in the wings, and when the film was run through it, with a strong light, against the background of the dark stage, the visions appeared on the cloud of smoke.”

“That’s it!” agreed Garry. “Now that I come to think about it, I remember that every night the spectre seemed to appear, there were clouds. In June there were fleecy, fluffy ones, and in July they were whitish thunderheads.”

“We’d better be sure, though,” Don argued. “I meant that we may know how the spectre was made to appear, but that wouldn’t be evidence in a court if we told Uncle Bruce and he had Mr. Tew arrested for trying to ruin the airport by scaring everybody.”

“But the courts accept what they call ‘precedents,’ I know,” Garry insisted. “If a lawyer says that another case was decided, before, on a certain kind of evidence, then the judge has to decide the same sort of case, on the same sort of evidence, in the same way.”

“But how does that help?” Don demanded.

“Well—look here!” Garry was very earnest. “I can give you precedents about pictures on smoke. One night I was taken to a film showing part of a prizefight, and there were a whole lot of men in the audience who smoked, so that the hall had a thick curtain of cigar smoke between the screen and the projecting machine—and the picture showed on the smoke—and, what’s more, the smoke was all glowing between the lens and where the smoke was so thick that the picture was clear.”

“I’ve read about a picture theatre out in the desert section of the country,” Chick stated. “I read it in a moving picture ‘trade’ journal Mr. Tew loaned me—about a dust storm in Kansas, I believe it was, where the dust was so thick in a theatre that the pictures they had to show appeared on the dust almost as well as on the screen!”

“What of it?” argued Don. “I’m trying to make you see that proving how a vision is made to appear doesn’t prove who made it show!”

“I see your idea!” agreed Chick. “It could have come from the control room, if the man on duty happened to have the right kind of apparatus to use for showing a film and could fix it to use the powerful airport searchlight.”

“Yes,” argued Garry, convincing himself. “I see that! And Mr. Vance could be there alone, any time, any night. He could have a projector ‘head’—the thing that snatches the films down in front of the lenses and then holds them each a fraction of time before the light to let the image get itself impressed on your eye. He could fix it to use the search beam, probably. He’s a wizard about lighting for night work on airways and in airports.”

“Look!” Don pointed down the street. “There’s his car. He was in the Palace, I think. Even if we didn’t see him, that’s where he was. Now I say, let’s get our bicycles and hurry down to the airport, and look around, before he comes back to his cottage to sleep.”

They hastened to their respective homes, securing the bicycles. In most instances somebody gave them a “lift” down to the waterside base, but each rode well, and was enduring and speedy on the pedals.

“The more I think about it,” Garry stated, pedaling swiftly and then coasting down the inclined road toward the water, “the more I think it over, the less I believe it’s from the control tower, and the surer I am that Toby Tew is the man who makes spook pictures on clouds.”

“He used the helicopter!” Chick contributed.

Don argued his conviction sturdily. How, he proposed, could a man in a helicopter throw a picture on a cloud without being seen?

“Our Dragonfly and the mail ’plane were the only ones visible—I didn’t see the helicopter at all, the night of the ‘spooking,’” he asserted.

“No,” Garry admitted, “but, for that matter, we didn’t see Scott in the Dart. In a black sky, with lightning flickering to keep your eyes altering the dilation of the pupils, we might have missed seeing them; but the helicopter was there, maybe floating just above the cloud!”

“It couldn’t have been!” Don was triumphant. “I drove right into that cloud!”

Swinging his handlebars to the left to pass down the airport road, Garry was silent: Chick, though, took up the argument.

“We can soon find out,” he declared. “We can search the control room and see if we find the least thing to back up Don’s notion that it’s the control chief we have to blame. I think, myself, Mr. Tew would be foolish—or brazen!—to show how the thing was done, if he was the guilty man.”

The control tower room was in charge of Vance’s assistant, who was busy taking down air condition reports from a radio with a headset. He nodded, and went on, concentrating his attention on the weather data which must be posted—and accurately—on the weather board in the pilots’ assembling room.

With the data typed, the assistant, knowing that Don was trustworthy and that no scheduled arrivals would ensue, left the room in the young pilot’s charge while he departed to post his notes; and the chance they longed for was made for them.

The search of drawers in the radio table gave no result.

No other section of the drawer space seemed worth looking into, and since no visible evidence of any projection apparatus other than the airport equipment was seen, they felt that prying was useless.

“Nothing for the control chief to use—you see that!” argued Garry.

“I suppose you think he’d have everything standing right out for everybody to see?” Don spoke witheringly.

“Well, then,” Chick seemed inclined to take Garry’s side, to suspect the man who operated a theatre and, thereby, knew most about the projection of images from and through moving picture films.

Don sent his eyes from wall to wall, from cupboard of spare instruments to unlocked desk drawers.

“Tew is the one to blame,” Chick persisted. “Vance told the truth about that tracing; he put his initials on it by chance, the way I’d make little stars in my geography book when I’d try to memorize the capitals of the South-Central States.”

“But—oh, shucks! What’s the good. I don’t know who it is. I think the control man is more logical than Toby Tew—and I like Toby best, too!” Don said, morosely. “But what’s the good of a theory, any way you look at it, unless everything fits.”

The helicopter didn’t fit in with the idea of the control room man projecting a moving scene on a cloud, he argued against his own ideas: at the same time, the helicopter failed to connect a theatre owner and boatman with such an idea. The picture on a cloud could have been evolved by either, since both knew about the angles of projection and the properties of light, concentration, angle and diffusion. But Doc Morgan had also acted in a suspicious manner, and certainly knew about the treasure, which, in itself, failed to fit in with the theory of Tew trying to ruin airport business for spite against its executive.

Coming back, the control assistant asked Don if he would stay until the assistant slipped across the runways to his boarding place for a ten o’clock cup of coffee and some cold lunch. Don agreed.

Getting his coat, the assistant caught his arm in an older garment hanging on a peg, and it fell to the floor.

They all heard the clink and jingle of some metallic object as it flew out of the vest hung under the coat and also dislodged.

The man bent, picking it up.

“What’s this?” he wondered aloud. “The Chief ought not to have keys loose like that in his old duds—Doc might knock them down the way I did and be too busy mooning over something to hear the noise—and a key would be lost.”

“Golly-to-Chriminety!” exclaimed Chick, running across to him, “let’s see that key, Chubby! It might be that it fits the cabinet where I keep the blue-prints—the one the blue-print of the ship plan was taken out of.”

“Oh, no! The Chief isn’t that sort. Anyway he lost a tracing, too!”

“I don’t accuse him of that!” there was a hidden meaning in Chick’s tone, “but somebody might have put this where you found it!”

“That’s right! Here! Try it!”

Don remained on duty, allowed the man to depart, and then waited expectantly while Chick rushed away on his errand.

Garry, on the balcony, using the binoculars to try and locate the helicopter’s upthrusting blades, heard his name called.

“Garr—ry!” The hail came from the lower floor.

He raced down the stairway.

Don, waiting, impatiently tried to hear the words that seemed to come up in excited, quick calls of amazement.

Soon his comrades came stamping up the stairs.

“The key didn’t fit the cabinets!” Chick set down the large black leather case he had been dragging along, and puffed for breath. “But—it—did—fit—one—of—the lockers—in the pilots’ locker room!”

“Oho!” Garry came after his smaller companion, dragging a compact and intricate-looking mechanism. Don, staring, recognized it.

“That’s a projector ‘head!’” he said excitedly. “And you found it, in a pilots’ locker—whose?”

“Oh! I don’t know that,” Chick argued. “I think it’s a spare one. What does it matter! The key was in the chief’s vest, the one he puts on when he is working around in here. What more proof do you want! You argued that he was guilty of throwing the spook pictures! Well——”

Don, examining the projector apparatus, which comprised an upper canister, or flat magazine, into which a reel of film could be placed, a film guide, a ‘gate’ and aperture, with mechanism for snatching the film through, and its lower guide and magazine, looked up.

“Open that leather case.”

It was only snapped shut, not locked. Chick and Garry got back the lid in short order.

“Here’s a roll of film.” Chick drew it out, opening the tin container protecting the celluloid material from drying out or from chance of fire. “It’s—an—aviation scene——”

“And the key to the locker was in the chief’s vest!” chanted Garry. “Your theory was right, Don.”

“I’m not so sure!” Don looked from the film to the projector. “It looks black for him, but—Garry how would you concentrate enough light from the big, open spot lantern here, onto the aperture of the projector head? See! The lens in that spot lamp is at least eighteen inches across, and that’s the diameter of the beam it throws. The part of the projector that the light has to concentrate on is less than two inches across! How about it?”

“I can’t tell you.”

“It was your theory, Don,” Chick reminded him. “Now you’ve got ‘evidence.’ You find out how it’s used.”

“I will!” Don accepted the challenge.

Studying the situation, the lighting conditions, and the materials at hand, he jumped up, turning an excited face to his comrades.

“This is how I’ll prove my theory—or test it, anyway,” he asserted. “Chick, rush down to the designing room, and get the big focusing cloth you use to cover your head when you have to focus the enlarging camera for detail print enlargements. Bring it up.”

Chick was back very soon with the big, rubberized square of black.

“Now,” Don came from an adjoining room where they had discarded flying togs that morning, “I’ll take the Dart, and go aloft—and fly out over the swamps. Chick, you and Garry adjust that focusing cloth over the projector head so it cuts off all the stray light that the beam lens won’t concentrate on the aperture plate. Then, when I set off a green Verey light, and it goes out and I have time to get my eyes used to the dark again, you open up the beam, and start turning the projector, with this film in it, trained on a cloud near where I am. We’ll soon test my theory.”

He got a mechanician, half asleep in the lonely hangar shops, had his help to start up the refueled Dart, warmed up the light ship, and signaling for the “mech” to release the tail he had been steadying against propeller blast, on the runway, Don sent the small craft into the water, taxied along its gently ruffled surface, got on the step and with full gun went soaring up to test a theory.

Short was his turn and abrupt his wingtip bank, to get himself headed for the marshes.

There, with a chosen altitude that he judged to be right for the angle of projection, he made ready to see if the tower beam had sufficient concentration and intensity to make a ghost of a film picture show on the cloud its beam might strike.

The green Verey flashed out, burned and died.

Gliding, watchful, Don’s eyes accustomed themselves to the dark.

A moment passed. Then, as he banked to come back, he saw it.

From a luminous cloud the spectre ship flew out at him!

CHAPTER XXI

A QUESTION OF ANGLES

Without wasting an instant, when he saw the silhouette of the spectre in the cloud, Don fired the Verey pistol set at the side of his airplane.

Arranged for the discharge of the Verey lights, the implement, fixed at one side of the fuselage, sent out into the air a bright, white flash.

The smoke bomb that Don used was such as pilots employ to show them wind direction. The light was almost instantly gone, being succeeded by the liberation of a dense volume of smoke that drifted in the light Summer breeze. But Don was not concerned with the smoke: he knew that watchful eyes had been ready to catch the flash, through the dark.

“They know, in the control room, that I got what I came for,” he told himself. “Now they’ll shut off the light and get everything put away before the control man returns from his late supper.”

With quick hands he set the controls to swing back, and made the return trip in as brief a space of time as the Dart’s power permitted.

At the runway, as he came to rest, Chick ran up.

“We got your flash!” he said, keeping his voice low. “Garry’s putting back the things. Let’s get the Dart back. You’ll have to explain the flight to the control man. He must have heard the take-off and landing.”

“Right. Well, Chick, one thing is settled, anyhow.”

“One thing? You mean——”

Don, unsnapping his helmet chin strap, put his lips close to Chick’s ear and spoke very earnestly.

“The spectre appeared. But!—it wasn’t from your projector!”

If he expected a cry of surprise, as his grip on Chick’s arm for a warning seemed to indicate, he was, himself, surprised.

“We know it,” Chick, to Don’s amazement remarked.

“You do? Then you saw it?”

“No, Don. Come on. Let’s not talk till we get back to Garry.”

He led the way to the stairs, and instead of going on to the control tower, turned aside at the door to the lower corridor.

“Let’s go into the designing department,” he suggested. “As soon as the control man returns, Garry will meet us there.”

“Just where I meant to go.”

Together they entered the room, lighting its dome bulbs.

“As soon as I saw the picture on the cloud,” Don stated, “I knew it didn’t come from the control room.”

“How did you find that out!”

Don, at the table, took pencil and paper.

While he sketched rapidly Garry entered. Chick put him in possession of Don’s news.

Watching, Garry nodded.

“Don knew, from the light angle, I guess,” he whispered.

The sketch Don made was proof of his accuracy of judgment.

It showed a small airplane, as though viewed from above. Its nose was directed toward a sketchy line that indicated the shore of the bay.

A little in front of its nose Don had made a small indication of a cloud. On that he put a straight line, that the others saw was meant to represent the “screen,” or place where the picture had been seen.

And the airport control room when he sketched it in, lay at exact right angles to that screen line!

“As the nose pointed West,” Don said, excitedly, “the light from your projector, coming from the South, would have been on the South part of the cloud. But the picture was on the East side, the one I faced. That’s how I knew you didn’t throw the picture. Besides, as I saw earlier, the diffused light from your beam, as it touched a cloud before the picture appeared, was very faint!”

“Q. E. D.” Chick quoted his school algebraic phrase.

“But if I saw the picture facing toward the West, how could you see it from the South!” asked Don.

“We didn’t!”

“Then how did you know, Garry? What proved you didn’t project it?”

Garry answered slowly.

“The film we had,” he explained, “started off with a couple of ‘shots’ of airplanes—flying over our swamp. But then it became a series of moving pictures, taken from the air, of water and marsh.”

“And that was all,” Chick added.

“The more things I see,” Don said after a long moment of thought, “the more I begin to think that Indian, John, had the right idea.”

“About Smith—the mail flyer?” Garry asked.

“Yes.”

“We will see a little later,” Chick stated. “His ’plane comes in after awhile.”

“Don’t forget,” Don argued, “that a man clever enough to do all the things we have seen done is bright enough to have somebody else fly his mail close to this airport, set down, and let Smith take it over and bring it in. For money, and with a man far enough away, it would be possible—and we could never check it up.”

“He’s still in that swamp, close by,” Don argued. “He is as brazen as they come, too!” Chick wondered audibly why Don had not flown straight up “to catch the man.”

“Alone?” Garry defended Don from a hint of caution. “Don did the right thing, coming back here. The stores haven’t reported a call for spare carburetor parts. The man is clever.”

“Maybe he got spare parts at Bennett Field, or Roosevelt Field,” Chick suggested.

Don held up a hand and shook his head.

“It isn’t important, just now,” Don declared. “Let’s make sure how the picture was thrown, tonight, while I flew around. Then we can work out why there is this extra projector head and a misfit airplane crash picture afterward, and about the carburetor.”

“Well, if you looked around, you must have seen the crate that the ‘ghost’ used,” Chick inferred.

“But I didn’t.”

They knew that he had not been careless: had a ship been in sight his sharp eyes, looking for just that, would have noted it.

“Listen,” Garry drew up a chair by the table, “Don, your knowledge of angles, and the things you had to study about angle of attack of a wing, and angles of incidence of air and wing, and all that, ought to help out here. This seems to be a question of angles.”

“It does,” Chick agreed. “What’s more, Garry, you’ve studied about light, because I know the control chief gave you some books when he saw that you took an interest in his work.”

“Maybe we can both get something out of what we’ve learned,” Don admitted. “Now—how?”

“Well,” Chick offered an opinion, “the old Indian gave us passes that showed us ‘how’ the ghost could be worked. Maybe there is a clue to ‘where from.’”

“Yes—I think there is!” Don caught a fresh sheet of paper, and began to draw a rough diagram of the theatre stage, sketching in the position of the pillar of smoke broadly.

“From what we’ve proved, about tonight, the stage picture couldn’t have come from the wings,” he stated. “It would have to fall on the smoke from the front, almost, or else the people in side seats might see it and not those in direct line, from in front of it.”

Garry drew the sheet to him, made an addition, showing the projection room of the Palace, up on its balcony.

“The theatre was made very dark,” he said, “and all the light on the stage was adjusted so that the sunset died out when the pillar of smoke went upward. Then the man at the film projectors in the balcony ‘faded in’ the picture—from in front, and at an angle ‘above’ the audience.”

Don jumped up, upsetting his chair in his excitement.

“Knowledge is Power!” he cried, excitedly. “Study of angles has given us the answer to Chick’s ‘where from!’ That shows why there is a helicopter hidden in the marsh!”

“I see it!” Chick was equally animated. “With the helicopter, the ‘ghost’ projector could hover above the clouds, well hidden.”

“Yes, and ‘throw down’ from that makeshift ‘projection room’ onto a cloud,” exclaimed Garry.

“He could hover very high,” Don contributed. “There he could see an airplane, coming, at a distance, gauge its direction, swing his own ship and descend to a point over a cloud. Hidden there, with his light on, and his film going through, the spectre would appear on smoke or clouds right in front of the coming airplane.”

“That’s exactly how, and from where, the ghost comes!” Garry agreed. “Now, here’s a suggestion, Don! Let’s ‘show’ everybody!”

“I don’t quite see—” began the young pilot.

“It’s almost midnight.” Garry consulted his wrist watch. “The Palace has finished the second show. The control chief and the others will all come here to see that everything is right, and for the arrival of the midnight passenger ’plane from the Maine Summer resorts. I’ll stay here and you, Don, and Chick, take the Dart, fly to where the helicopter is, with the projector and film, and when I give a beam signal that they are here, you two, in the helicopter, pick a cloud they can all see, and ‘put on your show.’ The minute that everybody sees how simply it is done, the ghost’s claws will be pulled—no pilot will be afraid and maybe—maybe your uncle will get a whale of a lot of business.”

“Yes!” Chick was enthused. “And Garry can see whose face betrays guilty knowledge, when the actual ‘spook’ is projected.”

“But—” Don saw the difficulties, “this isn’t the same film, hidden in the locker. Besides—where will we get the light?”

“The ‘ghost’ must get light from somewhere—” Chick began.

A flash of inspiration made him bang his palm on the table.

“The boathouse!” he exclaimed. “Don—Garry! I saw the Man who Never Lived come up from under that boathouse. That’s where he stores all his real stuff—light, and film, and maybe another projector, complete! This one is just in case he is suspected—to mix up the trails!”

“I believe Chick has the right idea!” Garry conceded.

“So do I! Come on, Chick! We’ll ‘put on a show’ and clear up the airport mystery of the spectre in the clouds for once and all!”

Again the faithful Dart, with two youthful occupants, took to the air.

And someone, behind the screen at the wash basin in the designing room, smiled, waited until Garry left for the control room, and then strolled nonchalantly back to the cottage where he roomed, and went peacefully to his quarters.

“There won’t be any more need for the ghost,” remarked the quietly smiling person to his shaving mirror. “Tomorrow the boys will be busy getting out of this little experiment—the engineers won’t be working, and it ought to be easy to find the chest that must have been buried when the mud in Crab Channel sucked down the brigantine, Lady O’ Fortune.”

Don and Chick, in the Dart, drove on, full-gun, to help his prophecy come true.

CHAPTER XXII

DARING AND DISASTER

Careless of the attention they might attract, Don and Chick rode the low altitudes toward the sheet of water before the boathouse. Chick had a parachute flare ready.

Don signaled.

Overside went the flare, to ignite and throw its fierce, white glare over the approach.

As it settled Don spiraled down, far enough away to make his pass at the water, power-stalling to a safe drop onto the surface.

He gunned the engine enough to bring them close to the old wharf and then let the incoming tide drift them, while Chick, out on a pontoon, sidewise to the piling, caught the rope they had cut and left hanging some nights earlier.

To draw the ship closer was no task.

Securing it, and taking the precaution of pocketing the parts previously removed from the helicopter carburetor, Don passed them up to Chick, whose agility had enabled him to reach the planking of the dock.

“Now,” Don helped by Chick, made the level and drew a small flashlamp out of his coat, “let’s see, first, if anybody’s up here.”

The light of the small torch danced to and fro as they stood in the open door of the old building.

“Nobody at home!” Chick declared, following the light into corners, behind the table, still lying on its side where it had been overthrown in the former struggles, and lifting the trap in the dark corner.

“Down we go!” Don whispered.

“Nothing to stop us.”

Their light, showing a rusting iron ladder, also revealed the surface of stagnant water, around a small landing stage, built to float up and down with the tide. Around it, thickly clustered, were the dozen dories owned by Toby Tew.

Boards, on the lee side, nailed to the string-pieces, served to keep wind out in storms, and since the boarding was carried down below the tide marks, disturbances from wind drift did not much affect the tethered crabbing boats.

“If we find anything,” Don held the light while Chick descended, head bent to screen his eyes, “if we find a projector, and a battery, it will narrow down our suspicions to Toby, and point to him after all.”

“It will!” Chick agreed, reaching up to take the light, then jumping from the lower rungs of the hanging ladder which did not quite go down to the platform, allowing for its rise with the tide.

“Here I come!”

Don, with Chick lighting his way, made the climb and jump.

“Nothing on the platform,” remarked Chick sending the beam to and fro.

“Put it on the dories—that’s it. There!”

A note of triumph was in Don’s voice.

They hurried to the edge of the platform, drew a dory close, and were quickly within its cluttered hull.

A tarpaulin, dragged aside, revealed, in the light, a good-sized box-like metallic contrivance, its sides rounded, with a sort of chimney on top: there was, besides, a large, circular tank, and a smalled metal case.

“Here’s a portable projector,” Don identified the metallic object, “and there is the ‘head’ and probably film, in that smaller case. But where does he get his light?”

“Maybe that tank holds acetylene gas,” suggested Chick.

Don, unfastening the projector lamp-house, exclaimed in elation.

“I know!” he cried.

The round, pure white object set in a holder within the lamp-house, identified by Don as a calcium disk, told him the source of light.

“This calcium gives the whitest, most brilliant light there is,” he declared. “See, Chick! The tank probably contains oxygen, under a strong pressure. Yes—there’s a gauge, and a pet-cock to regulate the gas flow. The tank connects, by this rubber hose, to the base of the burner, and the thing on the lamp, like a bent finger, pointing toward the calcium disk, is to throw the oxygen jet onto its surface. Then it glares like all get-out!”

“Let’s row the dory, and never mind the Dart: she’ll stay put,” Chick found oars on the staging in a big box.

They found quite a direct channel, along the shore line from the boathouse to the position in which the helicopter still lay tethered.

Expertly, as Chick obeyed his orders, Don assembled the parts of the apparatus in the cockpit of the helicopter. Iron, or perhaps aluminum, pieces, set into the coaming, enabled them to attach the portable projector, and to swing it to and fro, and direct it up and down.

“Did you ever fly a helicopter before?” Chick asked, as they perfected the connections between tank and the lamp base.

“No. But it’s simple! I mean—I can do it! You see, Chick, my flying experience will let me handle the tractor propeller, just the same as in the Dart.”

“I suppose so! And I see that all you have to do about the top set of blades is to throw in a clutch that meshes the gears on the upright mast. The mast is set in a step and bearing in the body frame. It is squared into the gear that turns it—I guess you can manage it.”

Don agreed.

Nevertheless, being a cautious youth who believed in being forehanded, he went over the curious, squat fuselage, tracing gas, oil, water-cooling and other feeds and piping. Then he examined the engine. Except that it was of a make he had not handled, it offered no difficulties.

Assuring himself that the gas gauge indicated at least several hours of fuel supply, and that he understood the controls for the lifting mechanism, Don operated the momentum starter. Its handle, rapidly rotated, gave a big, heavy wheel considerable momentum. Then, applying its control, he transmitted the power thus achieved to the engine and after several attempts the starter caused the charge in a cylinder to be ignited as the flywheel turned onto a point where a firing current passed into a charge of fuel mixture.

At once the engine took up its revolutions.

Don manipulated the throttle until he became fairly conversant with the power response, then, carefully, being sure that all was well, and that they had the film already threaded properly in the projector and that Chick comprehended the handling of the fuel for the lamp jet, he eased down the engine, let in the upper blade clutch, and saw the mast whirl its fan-like top slowly.

Gradually, as Chick cast loose the ropes, Don increased the speed of the upper blades, leaving the forward propeller idle.

The speed of the rotating fan soon began to be felt; but they did not rise.

“Don!” Chick, sensed a solution, having studied a good deal about the various points of airplane design, “remember that when a pontoon is in water, as it lifts, the suction of the surface increases and has a strong pull to keep it from leaving: that’s why they design a pontoon with a ‘step’ so the contact is with the top of the water, and not down in it.”

“That’s right,” Don agreed. “We’ll have to go forward a little as we lift. On land that wouldn’t be necessary. In water it may.”

The experiment was tried: he used the thrust-propeller, and in short order they were rising: then he cut out the forward speed, until he had made some tests of lifting speed with the horizontal blades.

“Here we go!” he cried finally. Go they did—up and forward.

“Aside from the handling of the upper fan,” he mused, “this isn’t much different from a slow cruising airplane. The tail and propeller control are similar—rudder and elevators; but I’ll have to remember the turn is made without ailerons to bank. We don’t have to bank on a turn. We just rudder around, and the upper blades keep us on a stable keel as we turn—here, we do it!”

Around swung the forward propeller, and Don directed the craft toward the higher levels on a slanting line that climbed it and also progressed it toward the airport.

He saw, when they came close to the open space, figures on the illuminated tower balcony, watching upward.

Someone blinked a flash lamp.

“That means ‘O.K.’” he murmured.

“We can put on our show!” cried Chick, also misinterpreting the signal that they did not pause to spell out in full.

Swiftly, with the engine gunned in, Don lifted the helicopter above the small groups of fluffy, white cloud that gave him excuse for his experiment. The airport vanished beneath the mist and the shrouding clusters of dense, smoky-white vapor.

Don swung the nose, as they hovered, drifting only slightly.

Thus he maneuvered into a position where his understanding of the angles they had worked out enabled Chick to train the projector on a mass of white vapor just over the edge of the bay.

He threw up his arm.

The beam of the white light glowed, and Chick quickly maneuvered it, through a threaded-up section of transparent, non-inflammable film, into the cloud. He began to turn the crank. Darkness ensued in the cloud as part of an opaque film covered the light.

Suddenly Don screamed.

“Stop!”

He threw up his arm, trying to signal Chick.

But the younger chum, intent on his handling of the intense light and the focusing tube of the lenses, as well as the proper course of the film as it jerked downward, paid no attention, failed to hear the cry and did not see the signal, his eyes being turned downward and away.

From the airport came screeches, as of warning, terror or distress.

The crash siren was going!

Don, from their high point, looking alertly around the horizon, had observed that the midnight mail ’plane, behind schedule, was coming, low and fast, over the swamp.

It all happened in a few instants.

On came the mail ’plane.

Up above the clouds, hidden from the mail ship by vapor, Chick cranked his projector.

As the mail ship approached, near the edge of the swamp, out on the cloud leaped the glow that suffused it, went through it, made of it a weird, terrifying set of illuminated atoms of moisture. Onto that plane of light leaped the black silhouette of an oncoming ship. The swing Don tried to make, to turn the vision away from its screen, did not help, since they had no forward speed to cause the rudder to work.

Hideous terrors gripped the young pilot. He knew what was about to happen. The pilot of the mail ship, already superstitious, and aware of the ghostly stories that had been flung far and wide, would look toward that cloud as he dropped the nose toward the airport approaches.

It couldn’t be helped. The spectre in the clouds was flying right at him as his ship disappeared from Don’s sight under the cloud over which they hovered.

Swiftly he cut the speed of the upper blades. They began to settle.

“What will we find on the ground?” Don muttered.

CHAPTER XXIII

AVENGING WINGS

Soon after Don flew away with his younger chum, Garry was rejoined by the control assistant. They sat talking for some time: then, as Garry’s frequent trips to the balcony became noticeable, the man asked their reason and Garry explained their intention.

While he finished his story, the control chief, Vance, with Doc Morgan, came out from town, in the former’s car: soon afterward Mr. McLeod drove back from his trip with the mail.

The airport executive was in high spirits. When, however, Garry detailed his story, the face of Don’s uncle took on a serious look.

“Don knows nothing about helicopters,” he declared. “Besides, this isn’t the way to accomplish results. I have detectives watching. If you had given them all this information it would have been better than for Don to try to ‘show up’ the trick. That warns the real perpetrator, puts him on his guard. The detectives could probably have caught him.”

“That wasn’t the worst feature,” the control chief volunteered.

“The mail ’bus is due in half an hour,” he declared. “Suppose that hair-brained nephew of yours decides to ‘put on his act’ just as it is coming in?”

Startled, Garry saw the force of the argument.

“Don is going to have the helicopter over the airport till he gets a signal and gives one,” he asserted. “I’ll signal him to come down, to give up the idea.”

Then, as another thought came to him, he added:

“I’d better get the Dragonfly warmed up and on one of the outgoing runways, sir. If anything should compel Don to land in the bay or the swamp—or if he didn’t recognize my signal—I could manage to fly the ‘crate’ that far—I’ve had fifteen hours solo in her.”

To that the others agreed, including the private detectives summoned from various posts about the airport where they were on watch.

With the help of the night mechanician, Garry got the Dragonfly out and set its engine going.

Then he hurried back to the control tower, to discover that the landing had been made by the Dart, as the flare had revealed.

Then there was silence, and alert, but futile watching, until Garry, watching the Northern skies, discerned the approach of the helicopter, as it swung along above the clouds, between two of which its light pontoons showed for a second.

Garry rushed to get a strong electric torch.

“I’ll send a blink-signal in Morse code,” he told Don’s uncle.

Waiting until the helicopter drifted down, he sent the signal which Don and Chick misinterpreted.

From that moment onward, all was confusion.

Garry rushed, with Mr. McLeod, to the Dragonfly, and prepared to take off.

The signal man in the control tower, watching the sky, sent them a triple flicker of the pilot’s spotlight, agreed on as a sign that the mail ’plane was in sight.

Then came the delay that was caused by Garry’s great excitement, so that he did not get the Dragonfly off the runway at the first attempt.

Instead, holding the elevators down too long, he got too near the end of the runway to risk trying to climb above some wires that ran in a diagonal line across the space ahead. Easily cleared in a correct take-off, they might have been the means of snagging the underbody with Garry’s slight experience in climbing angles and control manipulation.

The Dragonfly, just at the end of the runway, had to be turned, taxied back, and given a fresh start.

As he topped the wires on his second attempt, Mr. McLeod prodded Garry. The young, inexpert pilot, cutting the gun, and, fortunately retaining presence of mind enough to drop the nose to a glide as he cut power, looked around.

The man in the second seat pointed aloft.

In a quick look Garry took in the situation.

Fearing the worst, he seemed to sense its imminent arrival.

There, above the edge of the bay, a cloud was glowing. From his point of view he did not see the flickering picture, but he guessed it was either there or soon to appear.

He gave the nose a tilt upward, opening the throttle, as he saw the edge of the marsh seeming to rise up toward the Dragonfly.

As soon as he had climbed to a safer level he looked again.

There was the mail ship, coming down!

He again cut the gun for a glide, the better to watch.

His heart was in his mouth.

The mail ship was dropping swiftly. Suddenly it side-slipped.

Would there be a crash?

“Poor Don!” gasped Garry, “he has sewed himself up in an awful snarl if anything happens!”

At the same instant that the siren began to scream its crash summons he saw the mail ’plane come out of the side-slip.

To his amazement its pilot did not appear to be aware of the Dragonfly, cruising in a gently banked circle over the edge of the swamp, just beyond the end of the runways.

Instead, with a spiral, the pilot began to climb.

The beam of the airport searchlight flashed into being, and as it swung past that mail pilot, Garry, his head turned over his shoulder, caught sight of the pilot’s arm upraised, his fist clenched, being shaken furiously toward the upper air into which the mail pilot climbed.

“He’s wild with anger!” Garry decided.

He tilted his elevators to lift the Dragonfly, full power being on as he made as steep a climb as he dared.

He must get above the clouds.

If he could reach the altitude in time to signal Don to descend, the young pilot in the helicopter might avoid that sinister vengeance so clearly planned by the irate pilot of the mail craft.

Clearly Garry saw that the man had been anticipating some manifestation of the haunting spectre, had planned a deliberate reprisal.

Justly, as Garry realized, he proposed to take into his own hands the vengeance due for the terrible menace of the evil apparition.

“But—it’s Don—and his intentions were perfectly innocent!” Garry muttered, trying to edge the throttle a notch further on.

The clouds were just above him. He made his climb into a banked, turning ascent, passing through the thin edge of a fluffy vapor, to come out into the clearer air on a level with Don.

Already the young pilot was descending.

But this was not evident to the infuriated mail pilot who, coming straight at the helicopter from a swing on wingtip at a higher elevation over the swamp, made a ferocious dive, on wings of vengeance, for the ungainly ship Don piloted.

His intent was clear.

With his “propeller wash,” or slip-stream of turbulent air, he meant to upset the helicopter.

Garry held his breath. He could do nothing.

The mail ship passed just behind the helicopter.

It wavered, tossed, bent far to the side—began to go down—fast!

CHAPTER XXIV

SKY TACTICS

Clearly Don saw, as his helicopter wavered, teetering like a dizzy baby trying to stand alone, the venomous purpose behind that air disturbing swoop.

Chick, staring with wide eyes, his heart stopped, felt the sway and quiver of the cockpit and convulsively snapped the clasp of the safety belt he had released to operate the projector.

Up, in a zoom, after his furious dive, the mail craft’s pilot sent his ship. On wingtip, he came around.

Garry saw his intention.

So, too, did Chick and Don.

The dive had sent the angry flyer down a steep dive, past the helicopter and up, again, in a climbing zoom, to a high point on which he turned to come again past the other aircraft.

Garry realized that the man in that ship of doom was beside himself with passion, beyond reason. Don’s hand pressed the throttle. His own engine revved up smartly. The upper blades whirled faster.

“Can he climb away in time?” Garry gasped. Mr. McLeod, behind him, shouting, futile, helpless, gave up waving his arms at the mail flyer and watched Garry with wondering eyes as the young and inexpert pilot at the controls of the Dragonfly began also to increase his speed.

Don, opening up his fuel feed, felt the top fan catch in steady air, saw the needle of his altimeter tremble, begin to move forward. His tractor, or pulling propeller, also operating, began to show an effect.

But whether he climbed, at the same time moving forward, or not, the mail flyer could so adjust his next dive that it would sweep the helicopter’s air with that deadly, upsetting propeller wash. Garry, too, realizing that, came, as best he knew how, to the rescue.

With his flying speed picking up rapidly, he drove straight across the area between himself and the mail flyer. His eyes, watchful and narrowed, caught the instant at which the flyer ahead dropped his nose.

His own ship dropped its nose, and, with throttle, open wide, giving his engine full impulse the intrepid youth darted straight for the area where he judged that the other man’s dive would bring him.

Carefully, so as not to spoil Don’s own air too much and thus do what the mail flyer sought to accomplish, yet making his attack as close as his inexperience told him was safe, Garry drove for the point where the other diving ship should come.

That dive of Garry’s spelled an instant’s respite for Don. With a right foot slightly pressing rudder bar, Garry swung the Dragonfly in a gentle arc, as he went down, so that his path of flight went as far to Don’s side as possible: at the same time he would come back, he felt, into a line that must either bring the mail ’plane and his ship close, or the other, disturbed and disgruntled by his unexpected tactics, must side-slip out of danger.

That was not quite the result.

The mail ship, its control man seeing Garry’s purpose, drew up his nose, kicking rudder and banking—he sent the ship into an upward, sidewise skid.

It accomplished Garry’s purpose. Don, climbing and moving forward at the helicopter’s best speed, was out of the danger zone.

The few seconds of advantage he gained meant safety, because he had the helicopter righted and working under perfect control again.

Garry, cutting the gun, not skilful enough to dare sharp maneuvers, went on for some hundreds of yards before he thought it safe to bank and turn. A swift glance sidewise and backward showed him that the mail ship had come out of its skid, righted and again was executing a wingtip turn.

“Won’t the idiot ever give up?” Garry muttered.

Chick, watching the scene, unable to take part, saw one point of possible advantage, if he could only communicate with Garry.

In its climbing, forward position, the helicopter was close to the same altitude that the mail ship then had. Garry, in his last maneuver, had lost a considerable amount of altitude, and was, thereby, too low for anything but a climb.

Still, as Chick almost instantaneously thought it out, if Garry drove forward on a straight line, the imminent dive of the mail pilot would bring him into danger of a crash with the Dragonfly—if only Chick could get Garry to fly forward, on a level, at once, to get to that essential point where he would be in the required position, the mail pilot must turn.

With wildly waving arms Chick tried to attract Garry’s attention.

The young amateur, busy watching his controls, the steadying of his ship, planning his next course, did not at once see Chick’s movement.

Chick reaching forward, caught the detonating mechanism of the Verey pistol, which he knew Don had told him to load after their last signal.

Chick fired the green Verey light.

That made Garry turn his head.

With the pilots’ code, arm movements, Chick beckoned to Garry, as he saw the youth turn his head that way: quickly, then, Chick held an arm straight out in front of him. Rapidly he repeated the gestures.

As he began again to beckon, Garry, catching his idea, revved up, his ship came on, level-keeled and swift, just as the mail ship began to come forward, itself on a power-glide of an angle to bring it close to the helicopter.

But Garry, coming fast, saw the value of Chick’s signal.

Full-gun, he used every ounce of power, every hope of his earnest young championship for Don and Chick, to send that craft of his into place in time.

The mail ship’s control man saw that if he continued to come at the helicopter he must come also into a line of flight that would intersect that of the Dragonfly.

Unafraid, determined, if need be, to risk all to save Don from the vicious doom intended by the infuriated, senseless man who had tried to avenge a mistaken idea of the helicopter’s purpose, Garry held on.

The mail ship swerved away long before it came near Garry and the Dragonfly. Don, its pilot saw, would be above any safe dive he could make, and he suddenly changed his tactics, swerved and then, kicking rudder and banking—but in the wrong direction with respect to making a turn—the mail ship following its controls, skidded upward, straight for the helicopter.

But its pilot did not want a crash.

He thus got into a position where his sudden restoration of balance put him just forward of the helicopter.

There, revving up to full speed, he sent back over the tail of his ship that most terrible of all man-made winds—the straight, hard fury of his propeller blast.

Don felt the helicopter stagger.

With all his hope gone he felt sickish, as the blast came. Not alone his own, but Chick’s life, too, was about to be the payment for an impulsive plan.

But that Power above and beyond man’s puny hates, sometimes called Luck, oftener known as a good “break,” had caused the mail pilot to neglect to return his elevators to neutral; slightly raised, the tail surface caught the full effect of his own deadly slip-stream, sending the nose sharply upward, and thus making that fury of disturbed air pass only the tractor propeller of Don’s craft—so that its upper blades at their best speed were able to draw him up beyond the danger of worse than an instant of horrifying danger.

Stalled, the mail ’plane fell away, and its pilot had his work cut out to avoid a bad stall. Over the bay, although the clouds concealed it, the mail ’plane, without pontoons, must quickly get flying speed, or plunge.

Don, still rising, and Garry, flying toward the swamp, saw another airplane, with the unmistakable markings of the Government service, come swooping from a higher altitude.

Two red Verey lights, the imperative order to land at once, flashed out from the newcomer’s signal firing apparatus.

That new craft meant business, was commanded by some one in authority.

Going, on his glide, below the cloud scud, Garry circled out over the bay, came around to face the light breeze, took the water with his pontoons and shot toward the landing stages.

As he skittered over the surface he saw crowds rushing about in the wide area covered by the landing lights; evidently everyone driving home from late picture shows and dances had heard the bellowing siren; the airport day force was on hand; feverishly they worked to get the first mail craft off the runways, as the second came in.

Two handlers caught the Dragonfly’s wing as Garry drifted it to the landing stage. Further out on the bay, Don set down the helicopter, to Chick’s intense relief, without a jar. Shutting off the top blades the young flyer used the tractor prop to draw him to the place vacated by Garry.

On the landing wharf Don, as he made sure that Chick was again in possession of his normal color, saw Garry, in the lowered rays of the spot and other lights, surrounded by a group.

Doc Morgan was there, he saw. So, he was surprised to see, were the two Indians, old Ti-O-Ga and his son, John.

Cars were parking everywhere they could find space. Excitement was in the air.

“We’ve got a lot of company waiting for us to come home,” Chick whispered, with an uneasy grin.

“I don’t like it much,” Don responded. “Especially not the man in that ship that ordered us down. He looks angry, from here.”

“Well!” Garry pushed past the crowd assembling around Don and Chick, “Don, do you hear what they’re saying in the crowd?”

“Yes,” admitted Don, looking around.

“We’re elected,” muttered Garry. “They say the Ghost of Mystery Airport is caught!”

Mr. McLeod, behind him, frowned.

“I wish you boys had shown some sense,” he told the trio. “It’s all very fine to discover methods, and to tell others how mysteries are worked; but it is pretty dangerous to show off when mail is being brought in. That man in the other ’bus is a postal inspector, by his looks—or an army man out of uniform.”

“I know we were hasty,” Don said ruefully, “but—we will have to face the music.”

“I don’t think we’ll like the tune very much,” Garry observed.

“No,” agreed Chick, “Garry’s pretty sure to lose his flying license, at the very least.”

The curt summons delivered by the man who came to them from the last land ’plane to set down, shoving his way through the crowd without ceremony, proved that there was basis for their uneasiness.

“Well, young man,” the newcomer snapped, “you and your scapegrace friends will come with me, unless there is some one here, in authority who will guarantee your safe arrival before the New York Chief of my department at nine in the morning. You can’t fool with mail, trying your tricks and stunts to delay the mails—especially air mail!”

While Mr. McLeod conferred, sponsoring Don and his chums, Chick put a hopeful look on the face he turned to his comrades.

“We’ll have the real ghost by morning!” he whispered.

CHAPTER XXV

EIGHT HOURS’ LEEWAY

Taking their cue from the abrupt, antagonistic attitude of those who could overhear the Inspector’s words, the crowd began to mutter and to mill around, held back only by the lack of a leader. The lack might be supplied by any chance word of any among them.

“This is a pretty bad spot,” murmured Garry, softly, to Don.

“How about some football tactics?” hinted Chick. “We could break through the few between us and the helicopter. It would be warm enough to start easily.”

“We’re not flying any more tonight.” Don made a prediction he might find impossible to keep. “Here comes Doc Morgan, and the handling crew.”

Working their way through the crowd, the sturdy men who took the airplanes in charge, as well as several shop workers, led by the airport man-of-all-jobs, came around the edge of the staging, while Toby Tew pushed forward to join the group.

Toby, the theatre manager, with his sense of the way to handle an audience, stepped forward. The leader had arrived; but he was on the side of the threatened chums.

His brief speech, begun with a half-laughing, “Well, gentlemen, the show’s over,” and ending with a cleverly suggested hint that they might see something in the morning papers that would compel them to come to the Palace to see “Red Blood and Blue,” caused the crowd to suppose the whole affair was what theatre folks call “a publicity stunt,” devised to attract attention, bring about talk and advertise the picture.

“Thanks for the way you handled that,” Mr. McLeod remarked as the crowd, looking a trifle sheepish, thinking itself hoaxed into attending and helping along a publicity drive, melted away.

“Thanks for the ‘ad,’” Toby chuckled. “I saw a way to turn it to my own advantage—but, of course, I thought of it to get our young friends out of hot water.”

“Thanks, a lot,” Garry said. “They might have thought it would be a good time to give some harum-scarum fellows a ducking—or worse.” He became very earnest. “But, honestly, Mr. Tew—and all of you folks—” Doc, the handlers, the control chief and many friends, heard his statement at the hangar door, “—we meant only to try to lay the ghost of the spectre in the clouds, that was all, by showing how it was done.”

He was believed, and presently the group dwindled to the chums, the airport executive, Doc and Toby.

To their great surprise they were joined by the pilot whose liking for “spooks” had started the chums into the whole affair.

Limping badly, with a heavy swathing of bandages visible even under his loose trousers, on his left thigh, Scott came slowly in.

“Well!” he greeted them, “I see there’s been some excitement.”

“Why, Scott! We thought you were pretty bad when Uncle took you to the hospital last night. Glad you came out so quickly,” cried Doc.

“Oh—I had a good ‘break,’” the pilot said, but his face showed his strain, for he winced and drew wrinkles around his set lips as pain seemed to attend each halting step.

He had been grazed, he told them, by the flying propeller, when it had flung itself loose from its shaft on the Dart, the night before. The doctors and nurses, he explained, had patched him up—“Battered, but not busted!” was his summing up of his condition.

“They let me out tonight, and when I heard the siren I got a lift, but couldn’t get to you through the crowd.”

He was optimistic about the situation as it was explained to him by Don, Garry and Chick.

“I don’t think they’ll do more than suspend Don’s license for six months, at most,” he said, “and then only if the postal authorities see fit to notify the Licensing Bureau. Nobody got hurt, you see.”

“But six months would be a long time without any flying.” Don was despondent.

“Not very!” argued Doc Morgan. “It would soon go past.”

“But so will the eight hours between now—it’s near one o’clock—and the time we have to be at the Inspector’s office,” Chick declared. “If we could find the real ghost, and take him—or it—along, we’d be able to keep Don in the air—where he loves to be!”

“If the detectives can’t work it out, and the rest of us can’t make head or tail of things,” Scott grinned and then winced, dropping to a chair in the shop doorway, “how do you expect to manage it—in eight hours or so?”

“I don’t know,” Chick looked very serious, “but we’ve got an awful lot of clues if we can fit them together—there’s the rubber outfit, if we can locate it—oilskins, gloves—they’d have finger prints to test.”

“Yes—” Doc glanced suggestively toward Toby, “and the owner of a boathouse and dories, who would be likely to wear oilskins—he might be questioned.” Tew glowered at him.

“There’s that tracing, if we could locate it,” Garry added. “There might be fingerprints on it, too.”

Toby took his revenge.

“Yes,” he admitted, “they might be on the bottle—the one a certain person emptied or spilled, the night he was where the tracing was found!”

“When it comes to that,” Doc flashed back, “somebody had his initials on that—er—tracing, I recall,” he glanced meaningly toward the control chief.

“Casting suspicion and making mean remarks won’t get the boys along,” Scott hinted. “Have you any other clues? I don’t suppose you searched the boathouse thoroughly—or the helicopter, maybe?”

“We were too excited.” Garry turned quickly. “That makes me think—we might bring in the projector and the film cases—there might be a clue we didn’t notice in the dark. They ought to be kept in a locker, anyway—like the others——”

“What others?” Scott leaned forward, and then, perhaps recalled by pain to his injuries, he groaned, and slumped back, his lips set.

“We found—well, never mind,” Chick was about to tell their whole story when he caught sight of Don’s expression.

His eyes swung to follow those of his chum.

At the hangar doorway, on either side, were two intent, coppery-red faces, one old and seamed, the other young and alert.

The others followed the line of Don’s gaze.

“In the name of all-possessed!” exclaimed Toby Tew, “if it isn’t the Indians!”

Out rushed the crowd—down the runways toward the line of cottages backing onto yards near the swamp edge, raced the quarry.

They outdistanced the pursuit.

Old though he was, Ti-O-Ga kept pace with his son. The black dark of swamp, where none knew of any existing path, stopped the chase.

“Funny, wasn’t it,” remarked Don, as he returned to find Scott, unable to join them, waiting eagerly for results. “I never thought much about those two Indians—not in connection with this. But—that old one is smart—only-—why would they haunt the swamp, around here? I can’t imagine they have any grudge against my uncle. Uncle Bruce doesn’t know them, I’m sure.”

“Maybe Tew wasn’t so far off, earlier—how about it, Toby?—saying this was all a ‘publicity stunt’ for his picture!”

The theatre owner smiled a strange, unrevealing smile.

“I wonder—” reflected Scott. “Good stuff for the newspapers, if he did work it—but dangerous for the pilots! Man who Never Lived! A queer, disappearing map. Ghosts in clouds. When do you ‘spring’ the advertising part, eh, Toby?”

Toby was not permitted to reply.

Don, turning, saw Chick rush excitedly up from the staging where the helicopter was securely staked and tied to the waterside posts.

“Look!” Chick was so excited that he galloped toward them, capering and waving a large, round container, of some shiny metal, as he advanced.

In the case where they had found the projector and lamp, he cried, he had, on searching, discovered a can of film.

“I opened it to see if it was the same film we used,” he reached the group.

Scott started up from his chair, Doc came close, his face set and eager. Toby, with a muttered, “Gosh-a-mighty!” became very attentive. The injury of the pilot must have reminded him of its pain, for he sat down quickly again, wiping his brow.

“What did you find?” demanded Garry.

“Unexposed film!”

“Un—film that hasn’t been exposed?”

Chick nodded.

“But how do you know?” Don cried. “Film is all of the same yellowish color till its been developed. It could be exposed—and—oh, dear! I suppose you opened the can and there might have been enough light to fog the film—and we may have lost a very telling clue!”

“Maybe not!” cried Scott. “Take it up, and develop the first few ‘frames’ and see. You know how to handle the time-and-temperature tank powders, Chick. You go and develop some of that film. Don, will you and Garry help me to my boarding place? I’m—all in!”

They took him, limping painfully, to his bedroom. There he turned.

“Good glory!” he muttered, “fellow—I forgot! Doc—and Toby—and Vance—and those two Indians—are about the place—and Chick’s all alone with that—maybe it’s a clue! Sorry I brought you. Go back, fellows! Run!”

They ran!

CHAPTER XXVI

A “FLYING FILM”

Up to the dark room Don hurried with Garry.

At their knock a muffled voice came through the panels, hardly to be understood because of the weather-stripping used to make the joining of door and frame light-tight.

“He says he can’t let us in,” Don caught the faint murmur and interpreted it.

“Taking the film from the tank, I guess,” Garry responded. “We’ll have to wait.”

Five minutes passed. Then the door was opened.

Chick, with hands stained by contact with pyro and other chemicals, showed a disappointed face.

“No go!” he greeted his chums. “The hangar light fogged the film. It was light-struck, all right.”

“How about another test, from the inner end of the roll?” Garry suggested.

“We can try that,” agreed Chick.

Into the intense blackness of the room they crowded, and, by sense of touch Don extracted from the inner spool of the roll, an inch or so of film, while Garry washed out the developing tank used for the films they took of new craft for making half-tone engravings, pictures for circulars, catalogues and “trade paper” illustrations.

Chick, mixing a fresh charge of pyro, with sodium sulphite and the right amount of carbonate, from ready-prepared packets, enclosed the film in a roll of rubber-edged material that let the developer seep in but keep the fabric from touching the delicate film surface.

“Get the tank lid tight,” he warned Garry after the solution had been mixed and poured in, the film container being swished up and down to get the film full impregnated. “I have to light the bulb to time it and get the temperature of the mixture by the thermometer you just had in the tank.”

“Go ahead—it’s tight.”

They allowed twenty minutes for development; then the light was extinguished and the door, opened for ventilation, was closed.

In darkness Chick removed the film, handling its container gingerly as he immersed it in the hypo fixing bath to “set” the image. They gave it about half a minute of darkness in the fixing bath.

“Now we can see it,” he decided. “Switch on the——”

The door swung sharply outward.

There came a blinding flash, and with it the dense smoke of some pungent, gas-reeking chemical. Eyes smarted and watered. Staggering back from the surprise attack, totally unexpected, Don, Garry and Chick took an instant to cower back against the wall, shielding their faces.

There was the play of a flashlamp about the room.

Then, before either of them could recover from astonishment and from the choking smudge enough to move, there came the clank of some metal, and the slam of the door.

“Oh!” Chick gasped, and then said no more, choking in the smoke of the bomb or whatever poured its dense, stifling smoke up, filling the small, almost airtight compartment.

It took Garry, nearest the door, half a minute of choked, almost suffocated effort, fumbling in the dark, to get the handle of the door and twist it. The door was not locked; but, as he dragged Chick out and Don leaped over the fuming, pungent smoke-flare that had been ignited and dropped in the dark room, Garry saw that the rubber catch-all mat on the floor was burning.

The designing room, with its unreplaceable, valuable files, was adjacent to the dark room. Below, in the workshops, “dope” and other dreadfully inflammable materials lay stored. In the hangar next it were airplanes worth thousands of dollars, including a fourteen-ton, double-bodied seaplane that had been ordered by the Mexican Government.

“One go one way, the other to the bank stairway—or the fire escape!” he screamed to Don and Chick.

Himself, ignoring the lost film—knowing well that was what had vanished in the hands of their adversary—Garry raced for a fire extinguisher.

Choked, blinded, staggering, Don and Chick heard, but had difficulty getting their bearings.

Garry ran, full speed, back, to upset the chemical fire extinguisher so that its contents, mixing, would generate a gas to drown out the small, but menacing fire that had already touched the matting running from the designing room corridor across that side of the space.

Don staggered to the window, drawing in great lungfuls of fresh air.

Gasping, choked, he strained his eyes toward the grounds outside. Chick, at the corridor door, looked up and down, bracing against the dizziness that swung him on his unsteady legs.

Garry drenched the matting, the smoking flare, the floor and walls in danger.

The fire out, he dropped the extinguisher, and turning, raced, with Don and Chick, recovering rapidly, at his heels. He, too, was choked; but at the first opening of the door Garry had, fortunately, thrown a sleeve protectingly across his face, so that he had breathed less of the fumes than his companions.

Up to the control tower balcony raced Garry. Don went down to the hangars. Chick took the midway corridor, searching each office.

“There he goes,” shouted a voice.

Garry, rushing to the balcony, saw a fleet figure running across the grounds, out of the good light, but discernible. Into the searchlight Garry ran, while Don and Chick, hearing his shouts of response to the voice from below, went, careless of risk to limb, down the stairways at front and back of the big building. Garry, struggling to get the searchlight turned in the proper direction to pick out the fleeing figure, to identify it in a flare of vivid light, explained swiftly to the control chief on duty.

By the time the light was in position, on the roof, and its mechanism adjusted, the beam probing the velvety dark night picked up a scene of swift action.

Don and Chick, close to the hangars, were running, full tilt, out of the grounds, along the roadway.

A hundred feet beyond them were two heavier figures, pounding along at a slower pace, so that Don and Chick soon met, passed and out-stripped them.

Just beside the cottages that were boarding places and providers of furnished rooms for airport mechanicians, shop workers, pilots and others, a fleetly running, light form swerved out of the light just as Garry got to the balcony again.

Behind a house the figure vanished.

It had some round object clutched in the crook of an arm, Garry thought.

Standing there he watched until Don and Chick reached the spot.

In the bright rays of the light they soon returned, waving arms in dismay. While they stood, undecided, a window of the nearer cottage flew up.

Garry could not hear the voice, but he recognized Scott.

He watched as Don and Chick, calling upward, waited, received an answer, turned and raced back toward the hangars.

The upswung arm of Don, the upward pointing finger of Chick, told Garry what was wanted.

Down the stairways he plunged.

“Quick! Henry—help me!” he shouted, running toward the Dragonfly.

Don appeared at the door.

“That’s right!” He saw Don pushing at the tail of the aircraft.

“What’s it all about?” demanded the mechanician, to whom all this in-and-out pushing of the “busses” was mystifying.

“Scott called down to us. He was dozing when the light woke him. He got a glimpse of the man running away,” Don informed him.

“It was the Indian—John Ti!” contributed Chick, putting his weight behind the wing of the ship as he helped get it through the doors.

“Well—then he went into the swamps!” the man said. “That’s the only place he could get to from back of that house.”

“I know it!” puffed Garry.

“What do you want this crate for, then? You don’t expect to see a single, Indian kid, hiding in a pitch-dark swamp!”

“No!” gasped Don, “we don’t. But—Henry—we left the Dart tied there!”

“Get all the flares you can find!” Garry urged Chick, himself busy looking over the fuel gauges and oil supply.

Chick raced away, fully recovered.

They got the Dragonfly into the air in short order.

Three determined youths, each tightly strapped in place, each with a supply of signal flares, of rockets, of flash bombs, of white, red, blue and green Verey lights, went forth into the sky lanes, determined that their clue, considered important by Scott, should be recovered.

In the swamp a lithe figure, watching, seeing the ship coming over, muttered.

“He shan’t get away!” Don whispered, half aloud, to himself, in the Dragonfly.

“He shan’t get away!” muttered the lithe figure swiftly untying the Dart beside the boathouse wharf.

To which an older, more deeply copper-colored form grunted agreement, whirling the fight propeller to “contact!”

Then began a most peculiar sky chase!

CHAPTER XXVII

WHITE WINGS AND RED

Holding the Dragonfly barely higher than the wires he must top as he took off, Don sent the craft toward the swamp.

As soon as they swept beyond the cottages that backed their small yards on the undrained swamp, Chick sent overside his first white-light parachute flare.

“It’s only for safety’s sake,” he muttered. “That young Indian, if he knows the swamp at all, has had time to get across to the Dart. But he might try to fool us, and stop to hide. Not likely—but we must be sure!”

He, and Garry, watched over the side, a little afraid that with the craft of his forefathers the red-skinned John might so cleverly crouch in the eel grass that they might not see him.

Don dropped the nose, however, allowing the Dragonfly barely to skim the low patches of water, and clumps of gently waving marsh vegetation.

As soon as they got beyond the vivid glow of the light slowly floating down toward the marsh, Don climbed the ship three hundred feet, came around, side-slipping to lose altitude as soon after the next flare was ignited and launched as he could.

By these tactics, continued for several minutes, the three chums satisfied themselves that the Indian was at least not visible; and if he remained hidden for that long they had him!

“By now,” Garry decided, as he strained his eyes overside, “the police must have gotten out here to surround the swamp. Mr. McLeod agreed to get the Chief to bring all his force, and to send out his private detectives, and get every waterman to help as guides.”

Don, climbing away from the final flare, gestured ahead. As he gave a glance backward he saw Garry’s signal of agreement. They must get within easier guarding distance of the Dart at the piling of the boathouse.

As quickly as he saw that the swamp was being surrounded, the Indian might resort to flying for escape. It was not known whether or not he could fly the Dart; but Don surmised that he could. He had managed the helicopter.

When they climbed, steadily going ahead, to a good altitude over the swamp Garry turned his head, observing that Chick saw the same thing that he did as a white, floating flare lighted up the terrain beneath them.

There were two figures visible on the planking of the outer wharf at no pains to conceal themselves.

Instead, they were feverishly unfastening the light airplane, and Don, at Garry’s touch, nodded to show that he already was aware of the fact.

“That Indian can fly!” Don muttered.

He braced his nerves for an unusual effort.

Chick, too, was taut with excitement; his nerves tingled with expectancy; he would have little to do, yet he must be ready to play what part might be possible.

Garry, less excitable, was inclined to feel misgivings.

“What I understand about ship design makes me think this won’t be as much a test of skill as it will be of performance,” he murmured to himself, not having the Gossport apparatus because it had been left in the Dart.

“It is going to be a test between ‘controllability’ and ‘maneuverability’ this time,” Garry added softly.

He realized that airplane design taught the truth that a craft with a certain type of stabilizing fins, and control surfaces, might be very safe and steady in the air, and yet not respond quickly to its stick and rudder, because stability carried to that point might compel a sacrifice of quick answering to control movements.

“That’s the Dragonfly,” he thought.

Light, speedy, almost “touchy” in its easy response to control, the Dart, on the other hand, lacked that safety margin.

The Dragonfly could not go into and come out of aerial “stunt” positions with the same facility that the Dart had. The Dart, though, was so “touchy” that, with its margin of quick answering to controls, quick “stunting” possibilities, it was far less easy to keep in stable flying control.

“We can’t out-maneuver the Dart, if they once get into the air,” Garry decided, “but, then, the Dart isn’t as easy to hold steady as our ’bus is. One thing in our favor will be that Don knows this ship better than John understands the Dart. And—with Don against John,” he thought, whimsically, “it’s a queer thing that our Dragonfly has wings of white and the Dart is lacquered and doped in red.”

He smiled, being of a calm, humorous character.

“White wings or red?” he added. “We’ll have to see what we see!”

Don, almost over the boathouse at the moment, gave a swift look to estimate the progress made by the two beneath him.

“It will take a minute to warm up that engine,” he decided. “We can get into position!” His plan was to make a swoop from a fair altitude, just timed to take the steadier ship across the path of the other, and slightly above it, as it took off.

“The propeller ‘wash’ will throw him out of control too low to catch that touchy Dart,” he told himself. “It will put them down before they get high enough to be hurt badly. I don’t want to be the means of injuring anybody, if I can help it.”

He came around, and gave a quick glance to see the progress of the starting Dart. In the vivid light from a flare that Chick had put over he saw that the red-winged craft was beginning to skip over the water.

It was headed into the wind.

“Why don’t you tell him to dive?” screamed Chick, shivering with excitement and biting at his lip in vexation. Garry had deliberately ignored prodding by his younger comrade.

“Now!” Garry touched Don.

Has calmer nature had held in check his impulse to move too soon.

Exactly in sympathy with Garry’s touch, Don decided that the time to plunge, to rush past and above the Dart, and then to zoom away into the sky for a turn, and an observation, was just right.

Full-gun, with nose lowered, the Dragonfly dashed toward its target, coming up, in a gentle curve, just timed to sweep the turbulent air disturbance of their propeller through the area into which the Dart was just beginning to rise.

They swept with roaring engine across the sheet of water, their own pontoons and wheel-trucks not twenty feet away from the red wings.

Up they zoomed; Don brought the nose around with as sharp a bank as he deemed safe.

All three looked, expecting to see the Dart upset, and its occupant or the pair, if the older Indian had joined his son for escape, struggling in the murky water.

Instead, the Indian, with the cleverness that he had learned, as they discovered at another time, from enlistment at a Navy training school, had cut the gun, settling into the water again.

He had anticipated their maneuver.

Before they could get around and before Don could decide on whether to repeat the dive or to discover some other way of preventing ascent, the Dart strung in a boiling curve, one wingtip pontoon barely touching water to help it swing, and, with the wind, leaving in the water a hot, white seethe of broken wake, slanted sidewise to the breeze and rose.

With skill and quick yielding to control, the Dart swerved around into the wind.

Straight away, climbing rapidly, the small craft went.

After it, gunning up to top speed, went the Dragonfly.

On a level, Don’s speed about equaled the climbing speed of the angle taken by the Indian.

“Will red wings get away from white wings?” murmured Garry.

“Catch him, Don!” screeched Chick, unable to hold his quivering nerves as they made him tremble with eagerness. He felt like a coursing greyhound, urged on a trail but held by a restraining leash, willing to use his own effort, but restrained.

Garry, more controlled, watched.

Along the channel swept the strange chase.

Higher came the Dart. Straight at it, but some hundreds of yards to the rear, tore the Dragonfly, white wings chasing red.

“When he gets on our level,” Don murmured through clenched teeth, “his speed will get him away. If there was anything to do——”

Answering its easy controls as he stopped, surprised, the Dart, almost at their altitude, swerved.

Don, not expecting a turn, kicked rudder nevertheless, to swing on the new flight path.

The Dart, still climbing, made almost a complete, 360 degree turn.

At the half-way point, almost half a circle accomplished, Don went around on wingtip, to get the nose on a new point—he meant to make a direct diagonal across the turn, to try to meet, or forestall, the Dart.

But the smaller ship’s pilot, with gun full open, nose up, seemed almost to leap upward before he reached the stalling point.

He had caused Don to lose the advantage of altitude.

“Clever!” Don conceded, seeing the effect of the ruse. “Now he has only to fly straight away, and we will lose him in twenty miles.”

Chick uttered a cry of surprise.

Garry’s teeth shut tight in dismay.

Don caught his breath

Living up to the name, Dart, the lighter ship went into a wing-over, a maneuver by which, dropping a wing, and thus executing a turn, as it regained flying margin of speed, it exactly reversed the direction of flight.

The Dart, instead of going away from the Dragonfly, had completely altered the conditions: it was coming at the bigger craft.

Just above, and right over the Dragonfly came the other, full-gun.

Don felt the propeller stream tear at his right wing.

There his own ability, coupled with the great steadiness of the ship he handled, saved the situation.

Gently, not forcing or over-controlling, he recovered stability.

“Why!” Don screamed, “he tried to upset—us!”

The pursued had turned pursuer!

Wingtip went down, came up, steadied. Don again had control.

Over went Chick’s next flare, to light up the sky.

They picked up the enemy ship, quickly.

“He’s made an Immelmann turn!” shouted Garry to Don. By that maneuver, half a dive, half a climb, to get the ship to the top of a loop, and then a barrel roll, half-way, to bring it again on its proper keel, again the Dart was in position to swoop.

“He wants to drive us down, I think!” yelled Garry.

Although he could not hear for the roar of their own engine, Don also saw that the greater maneuverability of the other gave him an advantage they had not counted on. Thinking they were to be the hounds, and the Indian the hare, the chums found the conditions reversed. The hare, in his ruddy-winged craft, proposed to hunt down his adversary.

Don, realizing the danger to those with him, desiring no risk of life or limb or property, in the light of the flare, not yet dying, held up both hands in the old war-sign, “Kamerad!” and swiftly caught his stick and throttle again.

In the other ship the arm of the pilot pointed downward.

He did not, however, try to enforce the order to descend by any more swoops: instead, he maneuvered the light craft to a level with, and not fifty feet beyond the Dragonfly.

Don, uncomprehending, puzzled that they were being ordered down, when it had been his expectation to give that order to the other, let the nose drop a trifle, cut the gun, and went on a gentle glide, showing his intention to obey.

The young pilot, red of face, skilful of control, flew along, and as they came almost on a level with the flare, burning still, he turned his head for a glower of triumph toward his victims.

Don, his eyes turned that way to watch the wing separation, saw a look of amazement change the triumphant scowl.

The Indian pilot put out and waved an arm—he pointed toward the airport.

Don nodded, banked, submissively, so astonished and mystified that he could not further plan. Why had that coppery face shown astonishment?

It was a puzzle added to many problems.

With the other craft riding hard, above them, circling swiftly, the captors, now captives, obeyed the signal already given.

Over the edges of the swamps, searchers’ parties showed lights as they realized that the chase had ended, as they supposed. To them it appeared that a ship was being compelled by a skilful adversary to go back. That was true—but it was the pursuing ship that had capitulated.

Hardly had Don run out of speed, and, with Garry and Chick, leaped out to clear the runway, before the lighter Dart came home.

“For the sake of all that’s mysterious!” called Don as the Indian cut his ignition. “We thought you were trying to escape. What made you turn on us?”

“I thought you were the pilot I’m after—and I meant to get the man who stole our treasure chart!” Again the chums were stupefied.

CHAPTER XXVIII

THE STORY OF A MAP

Turning away, the red-skinned pilot helped his father to the runway.

The old medicine man was stiff from the cramped position, and somewhat shaken by his “stunting” trip through the air lanes.

Chick, belligerent and impulsive, followed John.

“What did you mean by throwing that smoke flare in on us?” he demanded. “You might have suffocated us!”

“I did not throw anything!” the young Indian retorted, cool and quiet, as he steadied his father. “We watched, that is all. Some one else is to blame, not I. And—when I find him!——”

Garry, seeing his face, felt glad that he was not the target of an emotion that contorted the copper-colored face into the mask of a veritable fury.

“Let’s go to the hangar,” Don suggested. “Maybe we can talk this out.”

“Come!” agreed Ti-O-Ga, moving away.

Doc Morgan, Toby Tew and some of the handlers who had stayed around discussing the exciting night’s events, looked disappointed.

“I think I’d like to come, too,” observed Toby. “In the name of all-possessed! This is a queer business.”

“It certainly is,” Doc agreed, and without invitation he ranged himself alongside of the theatre manager as the latter went with the party.

Mr. McLeod and the control chief joined them in the designing room.

Chairs and benches were brought. Everybody found a seat.

Chick, before he sat down, hurried to the developing room, as Don supposed, to estimate the damage done. Chick went in, did something, came out. Water was heard in the washing tanks.

“What did you mean by saying you thought we were the ones who had stolen a map?” demanded Garry, as Chick took his place again.

Readily enough, the Indian began to explain.

“My father has met a good many strange people, because he is so well-known for his cures,” he began. “A good many years ago he nursed an old sailor, and when he found he couldn’t cure him, Father told him the truth. The man was grateful, though, because he knew Father had done his best. He knew he couldn’t live, and he turned over to us a map.”

The map, he explained, was old and tattered. It showed, the sailor had claimed, a place in the Long Island swamps where, during a bad gale, many years before that, a pirate brig had been blown at high tide inland so far that it had become caught in the mud, and that ship, thus held prisoner, had been sucked down in a spot even then known as the Devil’s Sinkhole.

“And, as the man told us,” John continued, “the ship had some chests of jewels and gold and silver aboard.” He had been given a map, and the story, by his father. Coming down from generation to generation, the tale and the chart had yielded nothing to searchers.

“Jewels—gold—silver!” Chick spoke in awed tones. “A treasure ship!”

“Yes,” the young Indian nodded. “I was a schoolboy then. I went to Carlisle, and then enlisted in a cadet training school for naval pilots, but several years ago, when I was about to be graduated, the hard times struck the world and the navy decided not to take on any more flyers, and I was too young to become a commercial pilot, so I gave up my course and went to work at whatever I could get.”

“Many an army and navy cadet has been disappointed by learning he couldn’t keep on, after his enlistment term,” commented Mr. McLeod.

Garry, who had always felt a respect for the older man, now began to feel a strong liking for the straight-forward Indian, his son.

“I went to work at a Long Island moving picture studio as an extra,” John went on. “There I saw a chance to write and sell a story—and we made quite a good amount of money by playing in it.”

“We enjoyed your acting in ‘Red Blood and Blue,’” Don commented.

“But what about the map?” Chick broke in. “While we were working at Long Island City,” John informed him, “I used my spare time to study the swamps, and discovered that there was a spot, near this airport, known as Devil’s Sink. I was in the swamp a great deal, but if there had ever been a ship, the mud had covered every trace of it. We gave up, Father and I. But—and this is why I’ve told you all this—because I took an interest in aviation, I was around the seaplane base that was here before the airport was begun. I met some of the flyers. I suppose they wondered about our investigations, but of course we kept close mouths.”

“Any of us would!” agreed Garry.

“Father went back to the Catskills, to continue his doctoring,” John completed his astonishing revelation, “I went ‘on tour’ with the first of our films, making ‘personal appearances.’ That was before we had the smoke-trick scene thought out.

“When I came home Father told me about several of the airport folks, who had been visiting him. One was a pilot who said he was in the mail and commercial end of it——”

“A mail flyer!” cried Chick. “Well—that’s interesting!”

“You mean—Smith?” Don inquired, eagerly.

“That’s just the trouble,” John stated. “He came while Father was off doctoring a man in the back country. He called himself that. My mother isn’t very quick with her old eyes. He had his flying togs on, too, and she couldn’t describe him closely except that he was tall, and thin.”

“And so was the mail flyer who came in tonight,” Chick cried. “The one we scared, so that he turned on us and tried to force the helicopter out of control. We’re getting close to something—I think!”

The man they discussed, apparently loitering outside the door, came in.

“Is that so?” he said sharply, defiantly. “I can tell you that you will be getting close to trouble if you start accusing me——”

“What’s all the excitement this time?” Scott, limping down the hall, dropped gratefully into a chair that Don vacated. “I see you got the Indians——”

“They got us, you mean!” explained Garry.

“Well—any way you want it. Did you recover—the film?”

“No!”

“Didn’t they have it!”

“No!” John turned to answer courteously, “we had no film.”

“You’re interrupting a thrilling treasure story,” warned Don.

He and Garry, with interruptions from Chick, quickly put the pilot who liked spooks in possession of most of the important points.

“Well! It’s wonderful!” Scott commented. “We’ll soon have that gibbering spook in the open. I’ll keep still, though. Go ahead, Mr. Ti.”

“There isn’t much more,” the young Indian stated. “A mail flyer came to our place, while my father was away, and wasn’t very easy to describe, because of his flying togs. But one thing Mother did tell us—”

“What?” Chick was on the edge of his seat. “He had a little vest-pocket camera!”

“He took pictures,” commented Garry. “I wonder what for?”

“If you want my guess,” Don spoke up, “he wanted to get the locality clear in his mind, to study out how to go back—and—get the map.”

“Worse than that!” the young Indian told them. “Father thought little of the camera side of his visit until, first Doc Morgan, and then Mr. Toby Tew, and then Mr. Scott, came up, doctoring or for some reason that was covered by that excuse. He began to wonder, and wrote me. I cancelled my picture house engagements and went home—just before you two young chaps came along with the injured pilot.” Don and Garry nodded.

Their arrival, and the story he gathered about the swamp, and the odd apparition haunting the air, had made the old, wise medicine man wonder, John added. He had deduced, sagely enough, the real motive for the apparition. It was, as the Indians believed, no ghost-scare devised to ruin the airport owner and his venture.

“We decided,” John stated, “the ghost was being made to create a big scare among pilots and to keep them away from the swamp!”

“I think you are right!” Garry exclaimed. “I see it, now! If the flyer wanted to study that swamp—he’d do it from the air. He wouldn’t want other pilots coming along to catch him flying to and fro—but, at that—how would he know what to look for—and where?”

“The camera!” the Indian said. “Father went to his cupboard, where the map was stored, and found that while it had not been stolen, actually, it had been displaced. He had it under some other papers——”

“Was he sure he remembered just how it had been left?” asked Don.

“I got memory—never forget!” the old medicine man remarked briefly.

“Yes,” John agreed, “Father knew just how it had been—and it was not the same. It had been found—the look showed scratches where it had been picked, and then re-locked. That pilot had taken a picture of the chart!”

“That accounts for the tracing on thin paper!” Chick saw a clue. “He had to enlarge it, to study it, if he made the picture with a vest-pocket camera. That film isn’t much larger than the film in a motion picture camera—he enlarged it, and from the enlargements on tracing paper, he copied it—and then camouflaged the map on the tracing by adding the wings and struts and frames. And—then he slipped in the hangars and removed the tracing from Mr. Vance’s drawer, and took the blue-print I had made—so we haven’t got far, after all.”

“No,” Garry agreed, and turned once more to John.

“What did you do about it?”

“Came here, kept quiet, watched. I kept sending Father word, and tonight, early, somebody told me that mail pilot who had been up at our place once was flying the mail! I lost my self-control. I was in a rage, I hated that fellow. He had cheated, falsified his errand, imposed on my mother’s good nature——”

“Just a minute,” Scott broke in, “who told you he was coming in?”

“I got the call at the theatre—just before the ‘presentation’ was on the stage,” John stated. “He called me up—told me the flyer who had been at our place—and he knew I was looking for the man, he said—was flying in the mail.”

“Did he say who was calling?” Don was excited.

The eyes of the young Indian turned, covered the group.

They rested on Doc Morgan.

“You’re crazy!” The-man-of-all-work leaped from his chair. “I won’t stand for that, I won’t. You shan’t accuse me. I never called—I did not!”

“You did—I think I recognize the voice!” cried John.

“And was it you who flew over in the helicopter, out of the swamp, and tried to drive us out of control with rockets?” demanded Garry.

“Yes. My father was in the moving picture theatre, in the room with the projectors, and he wheeled the spot lamp across to a window, and used it to light up and blind you! But I thought you were the man who had taken our property.”

“So that’s how the queer searchlight came into our eyes!” snapped Chick. “You know what sort of crime that is? Endangering flyers!”

“We thought you were the mail ’plane,” John said regretfully. “Just as I thought you were the culprit trying to get away just now when I used the Dart to drive you down. But—I’m sorry.”

“You’d better be sorry you’ve accused me, too!” stormed Doc Morgan.

“Yes,” Scott agreed, “I’m not sure that isn’t all made up! What were you doing at the airport, just before the film was stolen from our young friends? I saw you—running!”

Chick sprang up.

“It doesn’t matter!” he cried. “Let’s stop accusing—and find out! The pieces we saved are about washed by now. Come on—Don-Garry!”

CHAPTER XXIX

CLUES IN CAMOUFLAGE

Smelling still of the fumes from the smoke flare, which someone—Doc Morgan probably—had cleared out, the dark room was close and unpleasant as Chick closed its door and, switching on the white printing lamp, faced his two friends.

“Let’s be very quiet,” he said, earnestly. “I was only half listening to the arguments. While they went on I thought of a way to draw the real ‘Ghost of Mystery Airport’ into the open—or—into the darkroom!”

“I don’t understand,” Garry spoke softly, although the door was tight.

“You mean by showing what we had clipped out of the film?” Don asked. “It was just put in the fixing bath—how do you know the fumes of the chemicals in the smoke bomb didn’t ruin it—stain it or fog it?”

“I don’t care a whack of a stick about the clippings,” Chick stated. “This is my plan. When I was in here before, I put the bits of film in the wash water, but they were all dirt, and chemicals. I don’t believe they’re worth bothering with. But—I know that the ‘ghost’ is among the people in the designing room. Doc followed Toby. Mr. Tew volunteered to come and listen. The air mail pilot was loitering around, listening. The two Indians——”

“Oh, I’m sure it’s one or the other,” Garry agreed, “but that doesn’t tell us your plan or how we can see which one it is. For my part, I’m in favor of looking at the film clippings. If they show us that we have the right idea, that a flyer has been taking pictures over the swamp, it will prove he is looking for the treasure, and not just trying to ruin Don’s uncle——”

“Oh, we know the motive—treasure hunting,” Chick retorted. “That’s been our trouble, before. We’ve tired so hard to show what was being done, and how, that we couldn’t take time and brains to discover—who!”

Garry was a trifle nettled.

“I suppose you are going to discover ‘who’ without even looking at the clue Scott thought might be in that undeveloped film.”

“I’m going to make him—discover himself!” Even Don stared.

Garry laughed, a little scoffingly.

“All right!” Chick took the implied unbelief good-humoredly. “Think this over: If you had flung a smoke bomb, and gotten away with evidence, and you heard somebody say they had some already developed—what would you do?”

“Run!” chuckled Garry.

“I wouldn’t!” Don saw Chick’s argument.

“I’d be uneasy, and uncertain, and I’d worry until, finally, I might feel compelled to come and see just how much you had against me!”

“That’s my plan!” retorted Chick.

Garry agreed with Don. It was clever of the youngest chum.

“While we wait, we might as well see if we have evidence, or whatever it may be—against anybody!” Don added.

Chick lifted the wet film from its washing bath, handling it carefully by the edges to avoid spoiling the wet, swollen, delicate surface emulsion containing the pictures.

Holding it up to the light, he showed a smoky, already somewhat distorted image in one piece of the clipped film.

“I can see—letters,” Don said, peering toward the light. “There’s an ‘A’ followed by a figure ‘one’ and then—it’s spoiled by scraping on the floor when the fixing trap got upset.”

“Just on the edge of the last ‘frame’ of moving picture film, you can see a flat, opaque blur,” Garry commented. “That’s an aerial picture, taken from above! I’ve seen those air photographs in the movies. What’s to prove this is a picture of our swamp? It’s all fogged!”

“I count more on our ‘ghost’ coming here than on that film,” Chick declared. “I’ll put that in a drying clip, and hang it behind the tanks in case we can use it sometime. Now, here’s the other clipping!”

The second one he exhibited was more clear.

“That’s the swamp, all right,” Garry commented. “The first one is one of the smoked-up parts we threw away after the first trial. But this one is the swamp, and no mistake. That is,” he corrected himself, “it’s a section of it, along the water front. See how the shore curves in and out—and the beginnings of Crab Channel and the other smaller inlets?”

Chick and Don assented; but the pictures gave them nothing new to go by, more than assurance that somebody had flown over the swamps to take air films. Of course, as Chick argued, that fitted in with the idea that the mysterious “somebody” had put the projector head and the other things into a locker of the pilots’ quarters as a means to throwing suspicion on another, as the key in the control chief’s old coat and vest proved. The film with it was not the same as that used for the apparition in the cloud. It was only a “blind,” as Chick argued.

Also, as Don added, the film could have been taken by the control chief as well as by another, except that he was seldom away daytimes.

“But Doc Morgan is,” Garry remarked. “And Toby Tew is in and around the swamps all Summer, and could easily hire some pilot from another airport to fly him—nobody would have paid much attention, because the engineers were using airplanes, too. And I think it was to stop the engineers from draining the swamp before he had taken the treasure that our ‘ghost’ worked his spectre-in-the-clouds!” he added.

“Sh-h-h-h!” Chick caught each by an arm. “Listen!”

Footsteps sounded on the floor outside, approaching. Were they hesitating? Did they echo with such caution because they belonged to a guilty body? Slowly they came closer.

There was a knock on the door.

“When I open the door—grab him!” Chick urged.

He waited. A hand tested the door knob. The door rattled a little.

“Open up!” came a muffled voice.

“Wait! Let him get anxious!”

A thumping came on the door.

Garry and Don grew tense. Chick’s hand was on the bolt.

It shot back.

“Now!”

Out they dashed, to encircle, to grapple with a figure standing off guard.

“Here! Stop that!”

The voice, deep and curt, made them draw back, look up at the form and face they released in amazed disappointment.

They had captured the Chief of Police!

“Uh—er—” Don stammered, “we—we expected—the—the ‘ghost!’”

“If you can prove you’ve caught him you can have my badge,” the good-natured officer chuckled. “As a matter of fact, I came in to see what was the result of your investigations. My men are all in the swamp, awaiting orders. We saw you bring in the Indians—they’re all out in the other room still, waiting for a report; your folks are, I mean.

“What have you got in the way of evidence, clues or proofs?” he asked.

They told him and showed him their bits of film.

“Wouldn’t stick in any court,” he stated. “Any finger prints are washed off long since, and the pictures could be cut from any news reel picture of airplane flights for observation purposes. No, boys——”

“We thought the ‘ghost’ would come to see what we had discovered,” Chick said lamely.

“Well, I’m not the ‘ghost.’ You’ll have to try some other scheme.”

“Don’t you think this ‘A’ and the figure ‘one’ might help?” asked Garry, indicating the smoked film, dimly showing the letters.

“It might—if there was anything to tie it up with.”

“If only we had the tracing of the Indian’s map,” Don said ruefully. “Or the blue-print Chick made—that had some sort of complicated figures on it—”

“Where is it—where is either one?”

“They were stolen, Chief.”

“Yes!—” Chick’s face became suddenly vivid with excitement, “yes!—but—when I made the blue-print, I picked up two pieces of paper and only discovered it after I had exposed the paper under the tracing!”

Hastily he switched off the white lamp, putting on the ruby light.

“I put the other sheet back, because it didn’t show much—but, you all know, there is a way to force up a stronger image—with intensifier chemicals.”

Feverishly Chick searched in the laboratory cupboard.

Garry aided him, while Don got the trays cleaned, and the Chief came in and closed the door.

Half an hour later Mr. McLeod caused the door to be opened to him.

“What’s going on?”

“Look!” Don’s trembling finger indicated a faint, but clearly discernible figure on a sheet of printing paper. The blue-print had been developed as far as it was possible to bring out the figure. Then a greatly under-exposed camera photograph had been made, on sensitive film, and this, by process of development known to Chick and the rest, intensified the lights and shadows which were more “contrasty” because of deliberate under-exposure. The result was a readable print.

There was the camouflaged map, apparently the hull outline of some old-fashioned ship, seagoing brig or privateer, with its sharply cut-under prow and overhanging stern, its roughly outlined deck and wavering waterline. Over that, distinguishable because in an ink that was dark and printed out whiter, was the outline of the airplane sketch.

“Camouflage!” Mr. McLeod agreed, “but——”

“Excuse me, Uncle!” Don interrupted. “If you will study that design, carefully, the way we have been doing for the past three minutes, and remember all that has happened, you’ll see that there are two clues in the camouflage. But we don’t want to stop to explain them. We want the ‘ghost’ to play his last ‘engagement’—and—we think he will!”

Then they walked out, in a group, to the larger room where the unsuspecting culprit waited.

CHAPTER XXX

BAITED WINGS

Never had Toby Tew “staged” at his Palace a better “presentation” than the one the chums were about to enact. With the Police Chief aiding, they had worked out a plan that must almost certainly bring their quarry to them.

Don, with excited face, raced through the designing section of the big hangar’s upper floor, at the end. Doc saw him; Toby saw him; so did others, under suspicion.

“All right, Chief!” he shouted over his shoulder, “sorry we haven’t room in the Dragonfly to take you along; but we’ll signal with a set of red, white, and blue flares when we find the treas—after we’re through.” He pretended to correct his supposed slip.

Old Ti-O-Ga barred his way to the door.

“You find?” he grunted.

“Think so!” Don admitted. “Tell you better after I’ve made sure!”

“Where you think you find?” The old Indian stood firm.

Don was secretly delighted: this gave him an opportunity.

“You see,” he explained, “after a photograph was made of your map, it was enlarged, and a tracing was made, of the larger size. That tracing was disguised with airplane parts, but it still looked like the hull of some kind of boat, a brig, or a brigantine. The ‘ghost’ was plotting the swamp out in narrow strips. The design enabled him to put lines across, looking like inch and foot divisions—but they were all sections of the swamp. You see, he flew to and fro, over the swamp, taking moving pictures. Then he kept a projector head here, in a locker, and when nobody was on this floor, at night, he’d develop his films, dry them in our dark room, and then project them by putting the projector head in front of our enlarging camera lamp. He was searching for any place that looked as though a ship had gone down. But—he was all wrong.”

“How was he ‘all wrong?’” demanded the control chief eagerly.

“He was looking for a sunken brigantine—or some sort of boat!”

“How was that so ‘wrong?’” the mail pilot, lurking in the background, wanted to know.

“We saw through the camouflaged design,” Don said. “We had a developed picture, what camera men in the movie colonies call a ‘shot’ of the swamp, from very high up—a wide-angle shot! It showed all the creeks and channels. We compared that with the blue-print we had—that the ‘ghost’ didn’t take away!” he spoke meaningly, “and we saw that the little mark probably indicating the treasure place, in the real map, that looked as if it was just a frame joint in the airplane sketch, and showed the treasure in the hold of the ‘brigantine’ at the stern, was really a mark at a point in one of the swamp channels!”

“You don’t say!” Scott bent forward.

“You see, the part of the map that looks like the deck of the brig—is—Crab Channel!”

“In the name of all-possessed!” cried Toby Tew, “tell us the rest—quick!”

“The wavy line is the other channel, almost parallel with Crab Channel,” Don was willing enough to speak, “and the line that looked like the stem of the ship was really the shore line between the channels while——”

“The bow part must have been the—” Doc Morgan was shaking with excitement, “—the little channel alongside of the boathouse.”

“Gosh-a-mighty!” Toby leaped up, “that cross in the tracing was right by the boathouse, then. In the name of all-possessed—to think I’ve been storing dories right over treasure—let’s——”

“Just a moment!” The Police Chief entered with Mr. McLeod. “Nobody goes out of here except Don and his Airlane Guard. The treasure is the Indian’s property if found. No one else gets a chance to rush ahead and secure it—if found! Stand aside, Ti-O-Ga!”

The Indian, realizing that he must obey, moved away. Don dashed out.

Anyone in the upper windows at the hangar side, watching, could have seen the Dragonfly take off almost before it had rising speed, and go roaring into the dark swamp air. They could have seen, and some did see, a landing flare go over near the sheet of water where the boathouse stood.

“Did you telephone—and get the answer we expected?” Don asked Garry as they tied up the Dragonfly to a part of the old wharf.

“I did, and Chick is about to unload what he found—in the boarding house room you mentioned!”

They took some cased objects, and a projector head, out of the cockpit, carried them into the old hovel, set them up by hooded flashlight rays, and then sat down in a corner to wait.

The water slapped and gurgled under the flooring. An hour passed. The wind that changes at dawn began to sigh and moan through the cracks of the old wall.

“Well—” Don stretched, wearily, “it’s almost dawn. Maybe our plan won’t work—listen! Here comes—somebody!”

CHAPTER XXXI

“THE MAN WHO NEVER LIVED”

Through the door came a muffled hail.

“Hello, inside the boathouse!”

According to a plan already made Don tiptoed into a dark corner as Garry went swiftly, silently, to the other, nearest the land side of the old building.

Chick, smallest, quickest of the three, crouched close beside the closed door, pressed tightly against the wall.

A hand fumbled at the latch. The door swung sharply inward. A beam of light leaped across the enclosed space. Instantly Chick lunged forward: his arms wrapped about a pair of slim legs.

“I’ve got him!”

As the man toppled forward Garry and Don came like panthers from the respective corners, springing on the figure. Realizing his helplessness their antagonist grunted a surrender.

Don kicked the door shut. Garry saw that his comrade placed his back against it, and let go his hold. Chick sprang back, tense and ready for any surprise move.

“Just as I thought,” Don said triumphantly. “The air mail flyer!”

“And what of it?” The man got to his feet, as Garry picked up the electric flash and laid it on the table, still glowing.

He directed its beams on a quantity of objects they had set there, ready for such a climax.

“We’ll tell you,” Don began. “First, Mister Pilot, you learned from the Indian, John, that there was some treasure hidden somewhere in this swamp. You went to the Indian village, concealing most of yourself in your pilot’s togs. Then you located the map Ti-O-Ga had, and took a picture of it with a vest pocket camera, came back and used our dark room enlarging outfit to make the tiny picture big enough to trace out and then you camouflaged that map tracing with wings and other airplane parts.”

Garry turned his light on various objects as he took up the accusation.

“This is the vest pocket camera.” He brought it into sharp relief. “Chick found it in your cottage room.”

“You’re crazy! I never owned one.”

“No use blustering!” Chick cried. “The whole thing is plain to us! You wanted a bigger map so you could lay out cross-sectional lines on it and number them. I made a blue-print of the tracing while we had it and by good luck I had picked up two pieces of paper to print on, and then put one aside, the lower one; but it was clear enough, after we made a contact negative from it on film, and then redeveloped and intensified that! We saw the cross lines, and the figures on the paper checked with figures on the bottom of the tracing, most of them being checked with pencil checks to show they had been covered.”

“And what did I do that for?”

“You laid out a chart of this swamp over the camouflaged map,” Don took up the accusing story, “then you went to Port Washington and bought an amateur movie camera, and a lot of film. Garry knows the photography store owner, and he got his home, tonight, and learned that a man in pilot’s togs who said he was a mail pilot, bought the outfit.”

The man was impressed. “Clever, but not true!” he scoffed.

“All through the mystery,” Chick cried, “you have been camouflaging! You covered your trail by putting suspicion on others. That tracing, in this place, puts suspicion on the theatre man, Toby Tew, because he was one who’d know how to do the ghost trick with an old airplane crash film and a projector.”

“You put the key to the locker where you hid the projector you used at the hangars, late at night, in the control chief’s vest, because he might have been able to cast airplane shadows on clouds with the searchlight beam!” Don spoke crisply, “and—you camouflaged the map—but, then, you overdid it!”

“Yes!” agreed Garry, “you went too far. You wanted to make the tracing seem like a new design, after you saw the control chief’s initials on the tracing he left here! So you drew in on the entering-edge of the wing’s a ‘slotted-wing’ sketch. Now, the control chief knows light, but he doesn’t know that a slotted wing is an invention that helps to reduce ‘burbling’ in take-off, and lets the ‘camber’ of a wing change automatically—that’s too technical for a control man. Only a pilot would know that, because it’s patented and controlled by one English firm.”

“And your camouflage showed us that the man we wanted must be a pilot, just by that!” cried Don. “Then we examined the frame-bracing and saw the little cross-mark you had to show where the map said to look for buried treasure—only you were looking for a ship!”

“All very cleverly worked out—but you’ve got the wrong man!”

“We’ll see! Chick, set off the red, white, and blue signal to the Chief,” Garry ordered. Chick’s move toward the door was arrested by a startling sound under the flooring. They all stood petrified.

Slowly they wheeled to watch the trap in the corner. It opened. Up came the green-capped, green-masked head, the oilskin shrouded body and rubber-gloved hands of their Demon—the Man Who Never Lived.

“Gosh-a-mighty!” he croaked hoarsely, “but you’re bright boys!”

“Toby Tew!” Chick exclaimed, recognizing the phrase. “You!——”

“In the name of all-possessed!” croaked the figure, “who else?”

“You’ve got your ‘nerve’ to brazen it out this way!” Garry said; but there was a strange look on his face; the voice, for all its disguising hoarseness, seemed oddly familiar—and not that of Toby. “Are you just doing it to try and save this mail flyer?”

“Gosh-a-mighty!” the figure retorted, “no! Time’s passed for trying to camouflage, that’s all. You think you read that traced chart? You didn’t! That cross telling where treasure was hid, now! I put it on the tracing to keep you away from the real spot, same as I bought an old, discarded skeleton from a hospital and had it discovered to start people looking in that locality—far away from where I dug and scooped in mud.”

“Well,” Chick cried, “you are caught! The swamp is watched. When you left the Chief, he had you watched.”

“Gosh-a-mighty! No such thing! He left us all go. All I had to do was to go home, start to go to bed, get these togs, walk down to the seaplane landing stage, tell the detective on guard I was a special officer assigned by the Chief to patrol the swamp shore—then in I got in that crash boat—and here I am, with good tail-winds and everything my own way!”

“You’re not Toby Tew!” Garry exclaimed.

“Toby doesn’t talk about ‘seaplane landing stages’ and ‘tail winds.’ Those are aviation and he’s a boatman as well as a theatre man—and he can’t fly!”

“Then it’s Doc!” cried Chick.

“No!” Don had caught the expressions and rightly judged them. “Doc couldn’t draw an airplane tracing: certainly the only other man besides this mail flyer, who knows about slotted wings and can make them is——”

“Scott!”

As Garry shouted it the disguised man nodded.

“But—Scott flew us here at the first,” Chick expostulated. “Besides—he’s injured!”

“Camouflage!” laughed the man, brazen and triumphant. “I got you to fly here to make sure you wouldn’t suspect me. Besides, it helped me get the ship here, so I could go in a dory to my helicopter, and ‘put on my sky show.’ Then—with the storm coming, I had the Dart to get back in: I used these oilskins, while I dug. I had the tracing made to guide my aerial photography, and as soon as I located the buried chest I left the tracing where it would get Doc suspected. I left a key where it might incriminate the control chief. The more people you suspected the more I could work. I had to burrow for that treasure—but—now—I’ve got it all loaded and ready to fly to a place where a boat can take me out to the twelve mile limit. There a rum-runner will ship me for parts unknown. As far as being hurt by the ‘prop’ goes, I pretended that to get out of flying that night—I knew the Indians were after me. And now——”

“You can’t escape!” taunted Chick. “The swamp is surrounded.”

“But the police left some very powerful arguments where I could get them—and they’ll help me escape instead of catching me.”

Then the figure on the ladder snatched a round, queer object from under its oilskins.

Instantly the reference to police supplies became clear to Don.

“Look out!” yelled Don. “Tear-gas—don’t breathe—run!”

The bomb flew, dropped, burst. Garry and Chick, their sleeves held over their faces, leaped toward the doorway; but the bomb, flung at Don’s feet spread its fumes swiftly. The trap door slammed to the roar of exultant laughter.

The pilot, off guard, stumbled against the table and fell. There came a cry and a cough—and silence. Choked, gasping, with smarting eyes streaming with tears, the chums staggered out.

“In case you might wonder—” Scott’s voice floated to them from the humming electric launch, “I left the hospital the same night I pretended to be injured by the propeller—I knew the Indian was going to try to drive me down, and pretended to be laid up. But I could run fast enough to come back, smoke you out and get the film—it had a picture on it I didn’t want seen—and I flung it out into the swamp and went back to my room—put the things that you found in that mail flyer’s room where you saw them—and came back to stay with the Chief till he sent me off to bed—only, I came here to load the treasure. Now—good-bye. It flies in five minutes!”

“Not much it doesn’t!” muttering, choking, coughing, Don gasped orders. Flares to signal, as soon as Chick and Garry got the pilot out of the house. His job was to start the Dragonfly. He staggered to the wharf-side, dropped into the craft—saw that the ignition wire was cut!

CHAPTER XXXII

A FLYING FINISH

Feverishly Don worked with spare cable to wire around the ignition switch and get his engine going.

From the boathouse staggered Garry and Chick, coughing, their eyes streaming. They dragged, by the shoulders, the unconscious pilot.

“His head must have struck something!” gasped Garry, dabbing at his eyes. Suddenly something snapped into his mind.

“Chick!” he choked and gasped, then turning, stuttered, “my first aid—kit! I left it—on—path—promontory—when—mail ’plane went down!”

Staggering, but bravely eager to help a man who was hurt, the youth took his way off the wharf, along the path, into the grass toward the end of the shore that curved out into the inlet, making the wavering line of the channel on one side.

The roar of an airplane engine came—but it was in the air!

Don looked up. There was the Dart, coming over, shooting the water landing, making its approach, coming in, setting down!

He recognized, at its controls, as he flung aside his helmet, the pilot who had been injured in the first crack-up, the night they saw the apparition: he had been driven down from the farm by its owner and was sufficiently healed in his arm to handle stick and throttle.

With him was the Police Chief.

“Get him?” hailed the officer, as the gas was cut and switch put off, and as Don shook his head, shouting his explanation, the Dart ran up close to the wharf.

“The swamp is surrounded,” the Chief cried. “We let them all go, as you had planned. Didn’t the culprit walk into the trap?” Don told him breathlessly what had happened, urged that the Dart go aloft and scout.

The Chief urged Don to occupy his place, while he attended to the man over whom Chick was working incompetently.

Don hesitated: they might need to use the Dragonfly, also, he protested. The newly recovered pilot suggested that Don fly the Dart, reconnoitering, as it was the less stable ship and in his condition he preferred the steadier, more easily controlled craft. They began the exchange, listening for a motor. No sound came.

Garry, recovering his strength, if still teary-eyed, blundering along to find his abandoned first aid kit, saw the Dart go in, and felt that for all his bravado, Mister Spook was almost as good as captured.

He broke through the tall grasses, near where the path ended.

His eyes saw an amazing sight! There, where the mail ’plane had gone into the mud, fresh planking had been laid across the mud, and on it rested the airplane, the boards concealed by wings and a camouflage of cut grass: its broken hull had been re-covered, freshly doped. It had no pontoons; but on each side of the fuselage slanted auxiliary wings of thin boards had been attached by wire. If it could be started and raced off the board support, he saw, the slanted planks would serve to lift it higher with each gain of speed, as a boat of the speed type is lifted by its side-flanges. And—in his disguising garments, Scott was working feverishly at the motor. Garry leaped forward. Scott tore off his mask to show a face of fury and dismay.

“Stand back!” Scott lifted a small missile. Garry knew the tear-gas and its effect. He hesitated.

“Shame!” he cried. “You can’t escape. Even if you did fool us by taking us to look for your own self, at the start, you can’t fool us any longer.” He was talking against time, getting his feet set.

“Come and turn that prop, or I’ll—throw this!”

Garry changed his tactics; meaning to leap, ducking the missile, he altered his plan. “All right!” he agreed, docile with pretended fear.

He moved toward the propeller, stepping on the edges of the boards.

He saw the electric crash launch floating just beyond the nose of the ship. Menaced with the tear-gas, he nevertheless made his leap, across the water, from the planks, that gave under him, to catch the coaming of the boat’s cockpit. The missile flew through the air after him, but Garry, in the channel, went down, until his feet touched mud; holding his breath he swam under the launch, coming up on the other side. He trod water, concealed.

To his dismay he heard the man, discarding his disguise, twist angrily at the propeller of the repaired airplane. It caught on a firing point of the engine, swung rapidly. The man rushed along the planks.

Drowned by the noise close at hand, Garry failed to hear the Dart rev up its engine, turning to get into the wind.

In it was Chick and at its controls was Don. Garry disregarded all danger, clambered into the boat, tumbling in close to the wheel and switch. He tore at the latter, sending current into the motor. With a howl of rage Scott drove his airplane off the makeshift runway and straight at the launch. He hurled a missile. It did not strike the boat.

Garry backed water, up the channel. The airplane had to take the air or foul its wings in grass. It rose. A bomb dropped—Garry, full speed astern, avoided it and backed up the channel. He could not turn.

Up soared the Dart. It came around. Don saw the mail ship turning to cross the bay. Full-gun, he took up pursuit, heedless of the Chief’s warning that their tear-gas, brought in case the swamp yielded the culprit, had been taken, must be in the hands of the escaping Scott.

Seeing that the Dragonfly’s pilot had trouble with his arm, Don knew he alone stood between Scott and escape.

The Dart was fast. So was the mail ship, once free of the water.

Garry, backing up the channel, saw Don fly over. He kept on, until he reached the wider sheet of water, backed around, swung close to the Dragonfly, climbed aboard, and feverishly begged to have a chance at the controls. The other pilot, not too strong, yielded. The Dragonfly started.

Don climbed, losing some advantage; but he knew that it would be a long chase—wanted it to be so. The man in the mail ship, with his bravado serving to the end, lifted and showed strings of jewels that flashed vividly in the first rays of the rising sun.

Don saw that Scott meant to cross to Connecticut. It would be a run across Long Island Sound. Don did not want to drive down the ship over water—he would lose the treasure.

He saw, far behind, the Dragonfly.

The crossing was made in record time, and then Don, in a ship easily maneuvered, raced up above the other. Then Chick screeched a warning.

Up toward them came one of those missiles—a tear-gas bomb.

Don made a quick barrel-roll. It caused the bomb to miss him.

Falling, the missile was in the path of the mail ship. Straight into it, as it fell, Scott raced. It smashed in his cockpit.

Doomed by his own act, he lost control, and in a slanting, catapulting dive, struck just beyond the shore line, on firm earth.

And thus the Ghost of Mystery Airport passed.

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Table of Contents

- THE GHOST OF MYSTERY AIRPORT
- CHAPTER I A PILOT WHO LIKED SPOOKS
- CHAPTER II THE AIRPLANE GUARD
- CHAPTER III THE SPECTRE IN THE CLOUD
- CHAPTER IV TEMPEST AND TREACHERY
- CHAPTER V STORM-TOSSED WINGS
- CHAPTER VI “THE THING THAT NEVER WAS”
- CHAPTER VII ABOVE THE STORMS
- CHAPTER VIII THE HAUNTED SWAMP
- CHAPTER IX ONE MYSTERY—OR TWO?
- CHAPTER X A CHARM TO CLIP GHOST WINGS
- CHAPTER XI THE CHARM SEEMS TO WORK
- CHAPTER XII DON FLIES THE MAIL
- CHAPTER XIII WAR MANEUVERS
- CHAPTER XIV THE SWAMP DEMON
- CHAPTER XV THE DEMON’S LAIR
- CHAPTER XVI CHICK TRACES THE TRACING
- CHAPTER XVII AN AERIAL CAPTURE
- CHAPTER XVIII A CONFESSION AND THE CHARM
- CHAPTER XIX A CLUE IN SMOKE
- CHAPTER XX DON TESTS A THEORY
- CHAPTER XXI A QUESTION OF ANGLES
- CHAPTER XXII DARING AND DISASTER
- CHAPTER XXIII AVENGING WINGS
- CHAPTER XXIV SKY TACTICS
- CHAPTER XXV EIGHT HOURS’ LEEWAY
- CHAPTER XXVI A “FLYING FILM”
- CHAPTER XXVII WHITE WINGS AND RED
- CHAPTER XXVIII THE STORY OF A MAP
- CHAPTER XXIX CLUES IN CAMOUFLAGE
- CHAPTER XXX BAITED WINGS
- CHAPTER XXXI “THE MAN WHO NEVER LIVED”
- CHAPTER XXXII A FLYING FINISH
- THE FULL PROJECT GUTENBERG LICENSE