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[Illustration: "Oh--my shoulder!" the man cried out in sudden anguish.
(Page 93)]




                                  THE
                             HAUNTED HANGAR


                             By VAN POWELL

                        [Illustration: Biplane]

                    THE SAALFIELD PUBLISHING COMPANY
                        Akron, Ohio    New York

                           Copyright MCMXXXII
                    THE SAALFIELD PUBLISHING COMPANY
                           The Haunted Hangar
                 _Made in the United States of America_




                                CONTENTS


  I "Suspicious Sandy"                                                 5
  II Ghosts, Gum--and Gems                                            13
  III The Sky Patrol Organizes                                        21
  IV Mystery Over the Ocean                                           30
  V Mystery in the Fog                                                42
  VI The End of the Chase                                             50
  VII The Swamp Gives Up a Clue                                       54
  VIII Sandy Meets a "Suspect"                                        64
  IX Jeff Encounters a "Jinx"                                         73
  X Larry's Capture                                                   82
  XI "Pop! Goes Our Mystery!"                                         95
  XII The Hoodooed Airplane                                          103
  XIII The "Hoodoo" Strikes                                          112
  XIV Dick Handles a Control Job                                     121
  XV A Trap is Baited                                                131
  XVI The "Bait" Vanishes                                            139
  XVII A Fight for a Fortune                                         146
  XVIII Outwitted!                                                   155
  XIX A Baffling Discovery                                           160
  XX Sandy Turns Over a New Leaf                                     168
  XXI The Sky Patrol Gives Up                                        176
  XXII The "Ground Crew" Takes Hold                                  182
  XXIII Larry "Solos"                                                190
  XXIV A Puzzling Development                                        196
  XXV High Wings!                                                    204
  XXVI The Race                                                      212
  XXVII Sandy's Discovery                                            220
  XXVIII Night in the Hangar                                         228
  XXIX Sandy's Trail                                                 239
  XXX Dick Encounters the "Ghost"                                    245
  XXXI A Triumph for the Enemy                                       250
  XXXII A Double Pursuit                                             255
  XXXIII A Battle Above the Clouds                                   263
  XXXIV The Emeralds Are Found                                       270




                           THE HAUNTED HANGAR




                               CHAPTER I
                           "SUSPICIOUS SANDY"


"Steady, all! Engine's quit and left us with a dead stick! No danger."

Neither sixteen-year-old Larry Turner nor Dick Summers, a year his
junior, had any more fear than had Sandy Maclaren, hardly thirteen and
seated just back of the pilot who, in flying the four-place, low-wing
airplane, had called back reassuringly.

"Jeff's a war ace and knows his stuff," Larry mused, "and the engine
couldn't have died in a better spot. We are high enough and within
gliding distance of that old, abandoned private field."

Dick, who saw something to make light of in any situation, turned with
his plump face cracked by a broad grin.

"I always said whether you fly a crate full of passengers or handle one
full of eggs, you get a good break sometimes!"

Larry nodded in his calm, half-serious way.

Only the youngest member of the trio, as the craft nosed into a gentle
glide and banked in a turn to get in position to shoot the private
landing spot on the old estate, took the occasion as anything but a
lark.

Dick joked, Larry admired the skill of the pilot.

And Jeff, chewing his gum casually, justified their confidence.

Sandy Maclaren, with narrowed eyes and an intent frown, bent his gaze on
the pilot's back and muttered under his breath.

"That engine didn't die. I saw what Jeff did. He was as quick as a
cat--but he didn't fool me."

His expression altered to a puzzled scowl.

"But why did he shut off the ignition and pretend the engine had
stopped--so handy to this old, abandoned estate?"

No answer rewarded his agile thoughts as Jeff skilfully shot the small
field, compelled to come in to one side because of tall trees directly
in their line of flight, over which his dead engine made it impossible
to maneuver. Nor did he get a solution to his puzzle as Jeff cleverly
side-slipped to lose momentum, and to get over the neglected, turf-grown
runway down which, a little bumpily but right side up, he taxied to a
standstill.

"Well," Jeff said, with a grin, swinging around in his seat and drawing
off his helmet, "here we are!"

"If I ever get the money to take flying lessons," Larry said, "I know
the pilot I'm going to ask to give me instruction! When I can make a
forced landing like that one, Jeff, I'll think I'm getting to be a
pilot."

"If ever I get taken into my uncle's airplane passenger line," Dick
spoke up, "I know who'll be Chief Pilot--until Larry gets the experience
to crowd Jeff out."

Sandy, his face moody, said nothing.

The tall, slim pilot, grinned at the compliments and then went on
working his jaws on the gum he habitually chewed.

"Guess I'll have to trace my gas line and ignition to see if a break
made this trouble." Jeff began removing his leather coat. "Say! By
golly! Do you know where I think we've set down?"

"Yes," Sandy spoke meaningly. "This is the old Everdail estate--the one
that's been in the newspapers lately because the people around here
claim the hangar is haunted."

"I believe it is!" agreed Jeff. "Why don't you three take a look.
Yonder's a hangar and the roll-door is lifted a little. Maybe you'd spot
that there Mister Spook and clear up the mystery while I work."

"I'd rather go down by the water and see if it's cooler there," Sandy
said, trying to catch Larry's eye. "Since we got down out of the cool
air it's the hottest day this June."

"I'm for the hangar!" voted Dick. "If there's any specters roaming
through that hangar you'll get more chills there than you will by the
Sound."

"I could stand a shiver or two," commented Larry, leading the way toward
the large, metal-sheathed building at the end of the runway.

Facing them was a wide opening, sufficiently spacious to permit
airplanes to be rolled through: in grooved slots at either side the
door, made of joined metal slats working like the old-fashioned roll-top
desk, could be raised or lowered by a motor and cable led over a drum.

Sandy gave in, and as they walked toward the hangar they discussed the
stories that had come out in the news about queer, ghostly noises heard
by passers-by on the state road late at night, accounts of the fright
the estate caretaker had received when he investigated and saw a queer,
bluish glow in the place and was attacked by something seemingly uncanny
and not human.

The door, when they arrived, was seen to be partially open, lifted about
three feet.

"There's an airplane in there--it looks to be an amphibian--I see
pontoons!" Larry stated.

"Let's go have a look at it," suggested Dick.

"Don't!" Sandy spoke sharply. "Don't go in there!"

Larry and Dick straightened and stared in surprise. It was very plain to
be seen that Sandy was not joking.

"Why?" asked Larry, in his practical way.

"Think back," said Sandy. "When school vacations started and we began to
stay around the new Floyd Bennett airport that had opened on Barren
Island, Jeff had his 'crate' there to take people around the sky for
short sight-seeing hops, didn't he?"

"Yes," admitted Larry, "and we got to be friendly because we are crazy
to be around airplanes and pilots, and Jeff let us be 'grease monkeys'
and help him get passengers, too."

"Surely he did! But when we brought them to go up with him, did he take
their money and fly them around, the way others did? Or----"

"No," Dick admitted. "He generally had something wrong with the crate,
or the wind was too high, or he had stubbed his left foot and met a
cross-eyed girl, or saw a funeral passing, and thought something unlucky
might happen from those signs."

"Do you really believe anybody can be as superstitious as Jeff tries to
make us believe he is?"

"Yes. Lots of pilots are--they think an accident will happen if anybody
wears flowers in their 'planes----"

"All right, Larry, let that go. But why did Jeff bring us here?"

"He said, this morning, we had helped him a lot and he didn't have money
to pay us," Larry answered. "He offered us a joy-ride."

"But why did he come so far out on Long Island, and _then get a dead
stick_ so handy to this old estate that hasn't been lived in for years
and that has everybody scared so they won't come near at night?"

"'Then get a dead stick!'" Larry shook his head. "Why, Sandy! I know you
read detective stories until you think everything is suspicious----"

"So do you read them--and Dick, too!"

"But we read to try to guess the answers to the mystery," Dick declared.
"You've got the idea that real life is like those wild stories.
Everything looks as if it had some hidden mystery behind it--I know what
will be your new nickname----"

He chuckled to show there was no malice as he stated the new name.

"Suspicious Sandy!"

"That's good," Larry smiled. "Suspicious Sandy thinks a pilot gets a
dead stick to make us land near a haunted hangar----"

"I saw him cut the ignition switch!" declared Sandy defiantly.

"You thought you did!"

"I know I did--and, what's more, here we are at a spot where nobody
comes because of the ghost story--and he tells us to go into the hangar
and--the door is left up a little way----"

"Oh, Sandy, you're letting wild imagination run away with you!"

"Am I? All right. You two go on in--and be held for ransom!"

"Ho-ho-ho-ho! That's good. Suspicious Sandy--is that somebody inside the
hangar?" Dick changed his tone suddenly, dropping his voice to a whisper
as he stooped and saw something move behind the old amphibian at the
back of the building.

"I thought I saw--but it's gone!" Larry retorted, lowering his voice
also.

By a common impulse of curiosity they stooped and went in. Sandy, his
own impulse following theirs, was inside almost as quickly.

"There isn't anybody!" Larry's eyes became used to the duller light that
filtered through the thick dust on the roof skylight.

To their startled ears came a muffled clang, a queer, hollow sound--and
as they turned to run back under the rolled-up door, it slid rapidly
down in its grooves, dropping into place with a hollow rumble.

"Good gracious golly!" gasped Dick.

"That's queer!" Larry was a little puzzled.

Sandy, half frightened, half triumphant, spoke four words:

"I told you so," he whispered.




                               CHAPTER II
                         GHOSTS, GUM--AND GEMS


For a long minute Dick, Larry and Sandy stood in a compact group,
feeling rather stunned by the sudden springing of the trap, as they
considered the closed hangar.

Larry, calm and cool in an emergency, was first to recover.

"Even if Jeff did want to catch us and demand ransom to let us go," he
remarked quietly, "he wasn't outside that rolling door--and I don't
think he could pull it down anyhow."

"No," Dick agreed, seeing no fun in the situation for once. "See! There
is a motor connected to a big drum up in the top of the hangar, and the
door is counterbalanced so that turning the drum winds up the cable that
pulls it up. I suppose the motor reverses to run it down and----"

"What was that?"

Sandy's voice was tense and strained.

They heard the strange, hollow sound again, seeming to come from the
metal wall, but impossible to locate at once because of the echo.

Rap--tap--tap!

"Somebody's knocking," Dick gasped.

"Not somebody--something!" corrected Sandy. "The same 'something' that
worked the door and shut it!"

"Gracious-to-gravy!" exclaimed Larry, "you don't believe in ghosts, do
you, Sandy? Not really!"

"No human hand touched the switch that ran that door down!"

"I think it did!" challenged Larry. "We thought we saw somebody at the
back of the hangar--that's why we came in! I'm going to see where he is,
what he's doing and why he's trying to fright--frighten us!"

He broke his sentence in the middle of a word because the queer knocking
repeated itself, but with quick presence of mind he completed his phrase
to steady Sandy, whose face was growing drawn with dismay.

Larry took a swift, sharp look around the enclosure.

"There's a big, closed can for waste and oily rags," he commented, "but
anyone would suffocate who hid in that!"

"Well, there's a clothes cupboard--in the back corner," Dick said.
"Let's look in that, you and I. Sandy, you stay back and keep watch."
Dick, quick to see Larry's attitude toward Sandy, wanted to have a
dependable chum at his side as he investigated while he hoped to give
Sandy more confidence by leaving him in the lighted part of the
building, under the smudged, dusty skylight.

"Come on!" agreed Larry.

With Dick he walked boldly enough to the built-in wooden cupboard,
protected from dust by a heavy burlap hanging.

Throwing the curtain aside sharply, both youths peered in.

"Nothing but old overalls and some tools on the floor," Dick commented.

"It's peculiar," Larry said doubtfully. "Nobody here--but--" a new idea
struck him. Quietly he gestured toward the amphibian, old, uncared for,
looking almost ready to fall apart, its doped wings stained with mould,
its pontoons looking as if the fabric was rotting on them.

Dick, instantly catching Larry's notion, went to the forward seat, while
Larry took the second compartment behind the big fuel tank.

"Nobody here," he reported, and investigated, by climbing in the vacant
part of the fuselage toward the tail.

"This place is empty, too," Dick agreed. "Where could?----"

"Oh!"--Sandy almost screamed the word as the dull, hollow knocks came
again.

Larry leaped from the wing-step, sent his sharp gaze rapidly around the
enclosure and, of a sudden, gripped Dick's arm so tightly that the plump
youth winced and grew chilly with apprehension.

At once he saw Larry's amazed, relieved expression and followed the
older comrade's eyes.

With an instant return of his old amused self he threw back his head and
let out a deep howl of delight.

"Oh--ho-ho-ho-ha-ha! Oh, my!--ho-ho----"

"What's the matter with you?" demanded Sandy. "Have you gone silly?"

"Oh--ho-ho! Suspicious Sandy!--ho-ho!"

Larry explained.

"You got us all worked up and worried," he told Sandy, "with your
suspicions. And all the time----"

"Ho-ho-ha-ha! All the t-time, we were like mice racing around a
treadmill." Dick had to speak between chuckles. "All the time we ran
around in circles so fast we didn't see the end of the cage.
Sus--suspicious Sandy! Thinking we would be trapped and held for ransom!
Ho, golly-me! Look around you, Sandy!"

Sandy looked.

His face slowly changed, gradually became red.

"Oh!" His voice was sheepish. "You mean the switch for the motor over by
that small metal door they use when they don't want to run up the big
one?"

"That runs the motor," Larry agreed. "The cable must have slipped on the
drum and let the door go down----"

"But," Sandy clung obstinately to his theories, "why did Jeff pick this
haunted place and cut the ignition--and why was the door up in the first
place?"

"What do we--ho-ho--care?" Dick chuckled. "Another thing--even if the
electric current is off and the motor doesn't work--look at that small,
hinged door--do you see that the knob of the spring lock--is
on--our--side!" He broke out in a fresh cackle of laughter.

"But--those raps----"

For reply Larry strode over to the metal door set in the wall for use
when anyone chose to enter or leave the hangar.

Throwing it open, he faced Jeff.

"Took you long enough to answer!" grumbled Jeff. "What made you fool
with that door and shut yourselves in?"

"What made you cut the ignition!" snapped Sandy, working on the idea he
had read in so many detective stories that a surprise attack often
caused a person to be so startled as to reveal facts.

Larry and Dick turned their eyes to Jeff.

The older pilot, staring at his accuser for an instant, as though
hesitating about some sharp response, suddenly began to chuckle.

"That-there is one on me!" he admitted. "You must have mighty quick
eyes."

"I don't miss much!" Sandy said meaningly.

"None of us do!" Dick caught the spirit of Sandy's accusing manner. "I
know you've been here before, too. There are lots of chunks of old
chewing gum stuck around in that front compartment of the amphibian--and
someone has been working on it, too. I saw the signs."

"Chewing gum?" Jeff was startled. Swiftly he strode across the dimly
sunlit floor, got onto the forward step, peered into the cockpit.

"That-there certainly is queer," he commented. "You're right. Gum is
stuck every place, wads of it."

"And you chew gum!" snapped Sandy, unwilling to be left out of the
suddenly developing "third degree" he had begun. Jeff made a further
inspection, touched a bit of the dried gum curiously, stepped down and
stood with a thoughtful face for a moment.

Presently he walked to an old soap box holding metal odds and ends,
washers, bolts and so on. This he up-ended. He sat down, his lean jaws
working as he chewed his own gum slowly. Around him, like three
detectives watching the effect of a surprise accusation, stood the
chums.

Presently Jeff looked up at them.

"Looks bad, this-here, don't it?" He grinned.

Dick, Larry and Sandy were silent.

"I guess I better explain," Jeff decided. "I didn't think you was so
suspicious and quick or I'd of done different."

"You can't trap us!" challenged Sandy.

"Trap you?----"

"Well, didn't you make friends with us and let us work on your crate and
help get passengers that you never took up? Didn't you say you'd give us
a joy-ride, then come straight here, cut out your ignition and make
believe you had a dead stick, land and then try to get us into this
haunted hangar?" Sandy ran out of breath and stopped.

"I do think you ought to explain!" Larry said quietly.

"Yes, I did all that--and I guess I will explain. I meant to, anyhow--or
I wouldn't have brought you here."

They waited, neither convinced nor satisfied.

Fixing accusing eyes on Sandy, Jeff spoke:

"I never dreamed you'd be suspicious of me! I made friends with you all
and tried you out to be sure you were dependable and honest and all
that--and I did bring you to this place because it is so far from
telephones and railroads. But I didn't think you'd get the wrong idea. I
only wanted you in a place it would take time to get away from if you
refused to help me."

"Help you--help you with what?"

Speaking seriously, Jeff replied to Larry's challenge.

"Help me save the most valuable set of emeralds in the world from
being--destroyed!"




                              CHAPTER III
                        THE SKY PATROL ORGANIZES


Amazed, Dick challenged Jeff's statement.

"Priceless emeralds--destroyed? You mean--robbers, don't you?"

Jeff shook his head.

"I don't think so--but I don't know for sure who it is. But I do mean to
ask you if you'd like to help me, and I don't think it would be against
robbers but against somebody that wants to destroy the Everdail
Emeralds."

"The Everdail Emeralds!" Larry repeated the phrase sharply. "Why, Jeff!
I've read a newspaper story about them, in a Sunday supplement. That's
the matched set of thirty emeralds----"

"Curiously cut stones," interrupted Sandy. "I read about them too!"

"That's the ones."

"Matched stones--and priceless," added Larry. "The paper said they were
a present to one of Mr. Everdail's ancestors by one of the most
fabulously rich Hindu Nabobs who ever lived."

"But who would want to destroy them?" Dick wondered.

"That-there is just what I can't tell you," Jeff replied.

"How did you get into this?" Sandy's suspicions came uppermost.

Jeff drew a bulky, registered envelope from his coat, displayed the
registration stamps and marks, and his name and address typed on the
envelope. Drawing out a half dozen hand written sheets in a large
masculine "fist," he showed the signature of Atley Everdail at the end.

"This-here is what got me going," he stated. "Want to read it or will I
give it to you snappy and quick?"

Sandy extended his hand and Jeff readily surrendered the letter.

"I'm letting you see I am straight with you," he remarked.

"You said we couldn't get away to tell anybody anyway," Sandy said, but
he was compelled to admit to himself that although anyone might write
such a letter--even Jeff!--the postmark was Los Angeles and the
enclosure had every appearance of sincerity.

"Never mind old Suspicious Sandy," urged Dick. "Let him read that, but
you tell us."

"It will check up, that way, too," smiled Larry.

"Suits me!" Jeff crossed his legs, leaning against the metal wall, as he
related an amazing and mystifying series of events.

"I'm pretty close to one of the richest men in America," he began. "You
see, we both enlisted in aviation units when the big war tore loose and
got Uncle Sam mixed up in it. We were buddies, Atley and me. Well, after
we came back I stayed in aviation, knocking around from control jobs to
designing new gadgets like superchargers and all. But when he went to
California and began to organize some passenger flying lines, I stayed
East in a commercial pilot's job."

"This letter starts off as if you were old friends," Sandy had to admit.

"Buddies--closer'n brothers," nodded Jeff.

"Atley Everdail sold out stocks and stuff here and went West to work out
some pet ideas about passenger transport," he told Dick and Larry. "Of
course he bought a big place out there and closed up this estate--put it
up for sale. Hard times kept it from selling, the same reason made him
hang onto that-there swell yacht he owned."

"I've seen pictures of the _Tramp_," Dick nodded. "One fine boat."

"She is that!" Jeff agreed. "Well, as Sandy must be reading, about where
he's got in that letter, Mrs. Everdail, who goes in for society pretty
strong, got a chance to be presented, this Spring, before the King and
Queen of England at one of their receptions."

"That's a big honor," commented Larry.

"Naturally she dug up all her finest jewelry," surmised Dick.

"And how!" Jeff nodded. "Now, that-there Everdail necklace that was in
his side of the family for generations--that wasn't took out of the
safe-deposit box once in a lifetime, hardly. Most generally the missus
wore a good paste imitation."

"But to appear before royalty--" Dick cut in.

"It says, here, she took the real necklace, on the yacht, when she went
to England!"

Sandy had lost his suspicious look. His interest, as much as that of his
older chums, was caught and chained by the coming possibilities and he
put down the letter to listen to Jeff.

"She did take the string, as the letter says," Jeff nodded. "It was a
secret--they didn't broadcast it that the necklace was in the captain's
cabin, locked up in his safe. Nobody knew it, not even the lady's
personal maid, as far as anybody supposed."

"Mr. Everdail didn't go with her," guessed Larry.

"He was too busy routing air lines and working out cost, maintenance and
operation plans for his big Western lines," explained Jeff. "But they
took all the care in the world of those emeralds. Even on the night of
the reception, the imitation string was taken to the hotel Mrs. Everdail
stayed at. That-there real necklace was brought to the hotel, in person,
by the captain."

"I don't see what could happen--did anything happen?"

"That-there is what started things," Jeff told Dick. "The missus was in
her private suite, in the dressing bowdoir or whatever it is, with
nobody but her French maid to help, and all the jewels in a box in the
room, hid in her trunks."

"What happened?" Sandy could hardly check his eagerness to learn.

"She was all but ready, dolled up like a circus, I guess," Jeff grinned,
and then became very sober. "All the jewelry was spread out to try how
this and that one looked, with her clothes, separate and in different
combinations."

"But what happened?" persisted Sandy.

"There comes a banging on that-there suite door to the hall and a voice
hollered, like it was scared to death, 'Fire! Fire--get out at once!'"

"Didn't she suspect any trick--was there a trick?"

"She didn't have time to think. That French maid went crazy and started
to hop around like a flea in a hot pan, and yelling, and it upset the
missus so much she forgot all about a fire escape on the end window of
the suite, and rushed out, snatching up all the strings of beads and
pearls and the pins she could carry. But, because she knew it was only
imitation and there wasn't anybody else around anyway, she didn't bother
about the emerald necklace."

"It was a false alarm--there was no fire!" Larry decided.

"All she found was a paper of burnt matches outside in the hotel
corridor that had been set off so when she opened the door she'd smell
smoke. Of course she ran back--and----"

As he reached for the letter, and searched on the fourth page, all three
of his listeners were holding their breath in suspense.

"Here it is," he declared, and they crowded around. "Read it, so you'll
see just what I learned about when she went back."

Bending close, intent and eager, they read:

"Some strong, pungent liquid had been poured on the green necklace," the
letter from the millionaire stated. "No alarm was given. My wife did not
want to broadcast either the fact that she had the real gems or the
trouble in the hotel. But people had heard the 'fire!' cry and doubtless
some suspected the possible truth, knowing why she was getting ready.

"Captain Parks came up later with the real stones and while he waited
for my wife to finish her costume, he examined the fire escape window
and was sure that someone had entered and left by that.

"Now Jeff," the letter concluded, "my caretaker on Long Island has sent
me clippings about a ghost scare on the old estate, and somehow I
connect that with the attempt to destroy the emeralds. I can't imagine
any motive, but there are fanatics who do such things from a warped
sense of their duty or from spite and hatred of rich folks. For old
times' sake, drop everything, get down to bedrock on this thing at your
end--do whatever you think best, but get in touch with the yacht, learn
their plans, cooperate with Captain Parks and my wife to bring that
necklace back to the vaults, and--I count on you!"

"Golly-gracious!" exclaimed Larry, "that's like a mystery novel!"

"But it's no novel!" Jeff said morosely.

"What have you done about it?" asked Larry.

Jeff explained. He had sent a radiogram to the yacht, and as its owner
had already sent one identifying Jeff, he was given the information that
the real necklace was being brought back, extra heavily insured in a
London company, by the captain himself.

"I located and rented this crate we flew here in," he went on. "I played
joy-ride pilot by day at the airport and hopped here of nights. But I
couldn't get a line on anything. I didn't notice that chewing gum until
you, Dick, Larry and Sandy--all of you--started your third degree and
showed it to me. But I did think--if anybody was playing ghost here,
they might be planning to use the old amphibian for something--maybe to
get away to get away with the emeralds if they could get hold of
them--in case anybody thought the yacht was due to lay up here."

"And that's why you brought us here--to help you watch?" Sandy asked.

"Not exactly. But it came over me that at night I didn't get anywhere
and I thought I'd try coming in the daytime--and being that the yacht is
due to make Long Island this afternoon, I thought I might need some help
with a plan I've worked out."

"What is it?" eagerly. Sandy wanted details.

"I've sent the caretaker here--he's as dependable as sunrise!--to a
place out near Montauk Point lighthouse, with Mr. Everdail's fast
hydroplane boat and I've sent a radio message to the yacht captain to be
on the watch to meet the hydroplane pretty well out to sea, and transfer
the necklace to the boat. Then, the yacht will come on and make harbor
here, as though nothing had happened--and all the time the emeralds will
be on the way, down the Sound and East River, to a wharf where I'll have
a motor car, with a dependable chum of mine, to take charge and carry
the package to safe deposit, get a receipt--and there you are!"

"I still don't see how we can help!" Sandy spoke again.

"I mean to hop out in the airplane, sort of oversee the business of the
transfer, and escort the hydroplane till she lands the emeralds, and
then circle around till my friend, with the receipt, goes up onto the
bank roof--it's pretty high up--fourteen stories--and wig-wags an O.K.
And I'd like dependable observers----"

"I'm one!" cried Sandy, his suspicions swept away. "Number two is named
Larry." "Dick is a dependable third!"

"We'll be a regular Sky Patrol!" exulted Sandy. "And watch what goes on
while you do the control job--and, that way--nothing can go wrong!" "Not
with the Sky Patrol 'over'-seeing!" Dick, too, spoke overconfidently.




                               CHAPTER IV
                         MYSTERY OVER THE OCEAN


Three youths, thrilled by the prospect of a mysterious adventure, and a
war pilot, intent on a friendly service, discussed plans for protecting
the Everdail Emeralds.

"I don't see how anything can slip up," Larry gave his opinion.

"I don't know," Jeff spoke dubiously, uncertainly. "We've gone over all
the things we can think of that might go wrong--but----"

"But--what?" demanded Dick.

"I had a fortune teller read the cards for me," Jeff told him. "The nine
o' spades--the worst card of warning in the pack--was right over me and
that means trouble--and the ace of spades, a bad card----"

"Crickety-Christmas!" Larry was amazed. "Are you really telling us you
believe in all that?"

"I've seen that-there card fortune work out before."

"You've twisted things that happened to fit what you wanted to believe,"
argued Larry.

"Oh, well," Jeff did not want to discuss his superstitions, "maybe it
won't come out so bad. I met a pair of colored twins yesterday. That's a
good-luck sign----"

"Look here!" Dick began to chuckle. "We've got a queer combination to
work with--our Sky Patrol has! Suspicious Sandy--and--Superstitious
Jeff!" Sandy grinned ruefully, a little sheepishly. Larry smiled and
shook his head, warning Dick not to carry his sarcasm any further, as
Jeff frowned.

"How will you know when the yacht is due?" Larry asked.

"I fixed up Atley's old short-wave radio, in the old house--and I've
been getting dope from the yacht the last couple of nights. In about an
hour we'll take off, fly out beyond the lighthouse and patrol."

"Will you have enough gas?" Larry inquired.

"Had some delivered in cans early this morning--down at the boathouse,"
Jeff told him. "We can fill up the main tank and get a reserve in my
small wing-tanks--enough for ten hours altogether."

"Let's get busy!" urged Sandy.

The three comrades were busy from then on.

Only when Jeff was warming up the engine, checking carefully on his
instruments, taking every precaution against any predictable failure,
was there time for a moment together and alone.

"Now what do you think of your suspicions?" Dick demanded. Sandy shook
his head.

"Most of the time I think I was letting imaginitis get the best of
me--but every once in awhile I wonder--for one thing, why doesn't the
yacht sail right on to the New York wharf and let the captain take those
emeralds to safe deposit?"

"Golly-to-goodness, you're right, at that!" Larry nodded his head.

"For another thing," Sandy went on, "anybody could write that letter
Jeff showed me--and who is Jeff, when all is said and done?"

"Oh, I think he's all right," argued Larry.

"Well, then, let that go. But--he chews gum and there's gum stuck all
over in this amphibian--he's been here, nights----"

"Suspicion may be all right," Larry commented, "but what does it bring
out, Sandy? What is your idea----"

"This is my idea! Nothing is what it seems to be. Jeff pretends to be a
joy-ride pilot, but he never takes up passengers--hardly ever. The
engine dies, only it's Jeff stopping the 'juice.' This old amphibian
crate looks as though it's ready to come to pieces and yet, somebody has
been working on it--that chewing gum wasn't stale and hard, because I
made sure. Well--suppose that Jeff was in a gang of international jewel
robbers----"

"Next you'll be saying the letter was in a registered envelope from
California and was written in Cairo!" laughed Dick.

"Or in New York!" corrected Sandy meaningly.

"Jewel robbers," Larry was serious. "I don't think that holds water,
Sandy. First of all, Jeff claims to know that the emerald imitations had
acid poured on them--acid to destroy them. That must be some chemical
that corrodes or eats emeralds. Now, robbers wouldn't----"

"Why not?" Sandy was stubborn. "Suppose they had gone to all that
trouble to get into the suite and discovered the false emeralds? What
would you do?"

"I might rip them apart--but do you think robbers carry acids along to
eat up emeralds if they think they are going to profit by taking them?"

"Suspicious Sandy," Dick began to chant a rhyme he invented on the spur
of the moment, "Suspicious Sandy, Suspicious Sandy, he thinks everything
is like April-Fool candy! Nothing is what it seems to be and soon he'll
suspect both Larry and me!"

Sandy turned away, hurt, and strolled to the amphibian with its
retractable wheels for land use and its pontoons for setting down on
water.

Jeff called and signaled that all was ready. Larry summoned Sandy but
the latter lingered, while Dick, a little sorry he had taunted so much,
followed Larry toward the waiting airplane. But Sandy, scowling,
hesitated whether he would go or be angry and refuse to join the Sky
Patrol. Then, as he clambered onto the forward bracing of the under wing
and leaned on the cockpit cowling, his face assumed a startled, intent
expression.

There was no chewing gum in the craft!

His first impulse was to rush out and declare his discovery.

His next was to keep silent and avoid further taunting.

"Jeff chews gum," he mused. "He pretended not to know any was in this
amphibian. But it's gone! Well," he told himself, "I'll watch and see
what he's up to. He'll give himself away yet!"

Assuming an air of having forgotten all about Dick's rhyme, he went to
his place in the seat behind Jeff and the instant his safety belt was
snapped Jeff signaled to a farmer who had come over to investigate and
satisfy himself that the airplane had legitimate business there; the
farmer kicked the stones used as chocks from under the landing tires and
Jeff opened up the throttle.

With wind unchanged the trees which had complicated their landing were
behind them. Jeff's only problem, Larry saw, was to get the craft,
heavier with its wing tanks full, off the short runway and over the
hangar.

"If he gets a 'dead stick' here," Larry mused, "it will be just too
bad!"

He had no trouble lifting the craft and flying for seconds just above
the ground to get flying speed after the take-off, then giving it full
gun and roaring up at a safe angle to clear the obstruction.

"We're off!" exulted Dick.

They were--off on an adventure that was to start with a mad race and
terminate--in smoke!

Down the backbone of Long Island, not very high, they flew. The farms,
landscaped estates and straight roads of the central zone were in
striking contrast to the bay and inlet dented North Shore with its
fleets of small boats, its fishing hamlets, rolling hills and curving
motor drives and the seaside with its beach resorts, yellow-brown sand
and tall marsh grass clustered between crab-infested salt water
channels.

Passing over the fashionable Summer homes of wealthy people at
Southampton, they held the course until Montauk Point light was to the
left of the airplane, then Jeff swung in a wide circle out over the
desolate sand dunes, the ooze and waving eel-grass of marshes and the
tossing combers of the surf.

"There's the hydroplane!" Dick, leaning over the left side, made a
pointing gesture. Larry, watching seaward, had not been looking in the
right direction. Sandy, alert to pass signals, touched Jeff and received
a nod from the pilot.

The first step of the plan was taken. They had made contact with the
small, speedy craft which, on a later signal that they had "picked up"
the incoming yacht, would speed out to sea to meet her.

"Now we'll climb!" decided Sandy.

Climb they did, until the sea dropped down to a gray-green, flat expanse
and only the powerful binoculars Larry was using could pick out the
cruising hydroplane slowly verging away from the shore in an apparently
aimless voyage.

"This isn't such a bad scheme, at that," Dick concluded mentally. "If
there should be anybody on the lookout--robbers or somebody who wants to
see what's going on--no one will see any connection between us passing
here and then climbing to get a good wind for a run down the coast
toward Maine, and a hydroplane that's acting as if it had some engine
trouble."

Higher and higher they went, probably out of sight of anyone without
strong field glasses, and while they swung in a wide circle, Larry's
binoculars swept the horizon.

"Smoke!" He turned the focusing adjustment a trifle. "Too soon to
signal--it may be an oil-burning steamer and not the yacht--or a
rum-runner of a revenue patrol--it's thick, black oil smoke, the sort
the yacht would give--it is a small boat--yes----"

His signal, relayed through Dick and Sandy to Jeff, shifted the gently
banked curve into a straighter line and swiftly the lines of the
oncoming craft, miles away, became clear.

Larry verified his decision that the low, gray hull, with its projecting
bowsprit, the rakish funnel atop the low trunk of the central cabin, and
the yacht ensign, identified the _Tramp_.

The signal went forward.

Jeff, glancing back, caught Sandy's nod.

"Now we'll dive to where the hydroplane can see us, and the dive will
signal the yacht that we're the airplane they'll be watching for," Dick
decided.

The maneuver was executed, ending in a fairly tight circle after Jeff
had skilfully leveled out of the drop.

"Smoke was trailing over the yacht's stern," Sandy murmured. "Now it's
blowing off to the starboard side. She's swinging toward us."

Through his glasses Larry saw the hydroplane awaken the sea to a split
crest of foam, saw a cascade of moiling water begin to chase her, and
knew that the tiny craft was racing out to the meeting.

"All's well!" he grinned as Dick looked back.

Dick nodded and passed the report to Sandy.

Sandy did not smile. Instead, as they swung, he scanned the sky. That
was not his instructions, but it was his determined plan.

"I'll see the amphibian Jeff was working on, nights," he mused. "It
ought to be in sight now----"

Convinced that both the hydroplane and the yacht would have located the
spot on the sea where they would meet, Jeff broke the tedium of his
tight circle by a reverse of controls, banking to the other side and
swinging in a climbing spiral to the right.

Closer and closer together came the swift turbine propelled yacht and
the surface-skimming hydroplane.

"I was right!" shouted Sandy, unheard but triumphant--and also a little
startled that he had so closely guessed what would happen.

He swung his head, signaled Dick, waved an arm, pointing. Dick and Larry
stared, while Sandy poked Jeff and repeated his gestures.

On the horizon, coming at moderate speed, but growing large enough so
that there could be no error of identification, came the amphibian. Its
dun color and its tail marking were unmistakable.

"The amphibian!" cried Larry. "I wonder why----"

"I wonder who's in it?" Dick mused as Jeff cut the gun and went into a
glide, the better to get a look at the oncoming craft low over the
seashore.

Larry realized with a pang that he was neglecting Jeff's plan.

He looked down.

No glass was needed to show him the yacht, swiftly being brought almost
under them by its speed and theirs. A quarter of a mile away was the
hydroplane, coming fast. A mile to the south flew the approaching
amphibian. And in every mind--even Jeff's, had they been able to read
it--was the puzzled question, "Why?"

Jeff began to climb in a tight upward spiral to keep as well over the
scene of activity as he could without being in the way.

"And to be high enough to interfere if something has slipped," Larry
decided on the purpose in Jeff's mind. Then, as the amphibian came
roaring up a hundred yards to their left, and in a wide swing began to
circle the yacht, Sandy screeched in excitement and pointed downward.

"Something's happening!" he screamed.

Swiftly Larry threw his binoculars into focus as he swept the length of
the yacht to discover what caused Sandy's cry, for with a wing in his
way he did not see the stern. They swung and he gave a shout of dismay
and amazement.

"Somebody's overboard!"

Instantly he corrected himself.

"No--but there's a life preserver in the water--it was thrown over but
the yacht isn't stopping." His glasses swept the bridge, the deck.

"No excitement--now, I wonder----"

The lenses brought the stern and after cabin into view.

Turning away, back to his view, in a dark dress, a woman who had been at
the extreme after rail was racing out of sight behind the cabin.

"There's a life preserver in the water!" Dick could see it without
glasses. Sandy looked.

"The amphibian is making for it!" he yelled.

"The hydroplane can't get there in time!" shouted Larry.

None of them realized that Jeff's roaring engine drowned their cries.

"Jeff! Look----" Wildly Sandy gesticulated.

Fast and high, in a swift glide, coming like a hawk dropping to its
prey, a light seaplane, skimming the edge of an incoming fog bank,
showed its slim, boatlike fuselage and wide wingspan, with two small
pontoons at wingtips to support it in the surf.

There was a swift drop of their own craft as Jeff dived, came into a
good position and zoomed past the yacht, close to it.

Wildly, as those on the bridge came into clear view, Sandy, Larry, Dick
and Jeff gesticulated, pointing astern. Bells were jangled, the yacht
was sharply brought up by reversed propellers and a tender was swiftly
being put down from its davits, an excited sailor working to start its
engine, even as it was lowered.

Then, helpless to take active part because they had no pontoons, the Sky
Patrol witnessed the maddest, strangest race staged since aviation
became a reality. And the prize? A mysteriously flung life preserver!




                               CHAPTER V
                           MYSTERY IN THE FOG


While Sandy watched the amphibian and Dick stared at the rapidly
approaching sea plane, Larry gazed at the swift hydroplane and noted the
feverish attempt on the yacht to get its tender going as it struck the
surging water.

Swiftly he snapped the binoculars to his eyes as they receded from the
yacht in the onrush of their zoom.

A woman in dark clothes had rushed behind the after cabin.

She must have tossed the life preserver from the stern.

But there was a woman on the bridge with the white uniformed captain and
a navigating officer. She was in dark clothes! But she had been there
all the time. He suddenly recalled the French maid Jeff had mentioned in
the hotel. That answered his puzzled wonder. He knew who had thrown that
life preserver, at any rate. It could not be the mistress. It left only
the maid to suspect.

Fast as a dart the hydroplane cut the surges.

"She'll get there--they see the life preserver!" he cried, looking past
the tilting wing as they executed a split-S to turn to head back the
quickest possible way.

"The amphibian can set down on the water and she'll pass the
place--already there's somebody climbing out of the front cockpit onto
the wing--to grab the thing as they pass!" Sandy muttered.

"That seaplane is coming fast!" mused Dick. "What a race! It will be a
wonder if there isn't a smash when they all come together!"

It took only seconds for the race to conclude.

With a warning cry that was drowned by their engine noise, Larry saw
that the amphibian was in such a line of flight that it must be crossed
by the course of the hydroplane--and from the respective speeds, as well
as he could judge, there might be either a collision or one of the craft
must alter its course.

"The seaplane is almost down on the water--and coming like an arrow
toward that white preserver!" gasped Dick. "Will its wings hit the
yacht?"

"Can't we do anything at all?" Sandy wondered desperately.

Evidently Jeff either caught his thought or decided on a course through
his own quick wit.

Opening the throttle full-on, he kicked rudder and depressed his left
wing. Around came the airplane. Skidding out of her course from the
momentum and the sharp application of control, she moved sharply upward
and sidewise.

Deftly Jeff caught the skid.

Righted, Sandy exultantly screeched at the maneuver.

Flying fast, in a steep descent, they went across the nose of the
amphibian, and in the turmoil of their propeller wash she went almost
out of control, and before her pilot caught up his stability the
hydroplane raced across her path in a slanting line and made for the
small round object bobbing in the trough between two swells.

But that gave the seaplane an advantage.

Quick to take it, dipping a wing and kicking rudder, the seaplane's
pilot swerved a little, leveled off, and set down in a smother of foam,
and on his wing also a man climbed close to the tip!

"Where's the one who was on the amphibian wing?" Larry wondered.

"In the water, spilled by our wash," he decided.

He had no time to pay attention to that situation. The imminent
culmination of the race chained his gaze.

"The tender is almost there--oh!" gasped Sandy, "the seaplane must be
rammed by the tender!"

But the yacht's boat, with its motor hastily started, and cold--lost way
as the engine sputtered and died!

Slackening speed, the seaplane raced along until, with a hand clinging
to a brace and his body leaning far over the dancing waves, its
passenger on the wing scooped up the life preserver.

Almost immediately the seaplane began to get off the water.

The tender, its engine missing badly, turned its attention to the man in
the water, but before it could get to him or near him Sandy, Dick and
Larry saw that he caught the tail assembly of the amphibian and
scrambling over the fuselage as the craft picked up speed, fell flat on
his stomach just behind the pilot's place and clung tightly while the
craft got "on the step" and went into the air in a swift moil of foam
and a roaring of its engine.

Outgeneraled, the hydroplane cut speed and swung toward the yacht,
followed by the tender.

The race was out of their hands.

"It depends on us!" panted Sandy. "Jeff--get after that seaplane!"

Their pilot needed no instructions.

Kicking rudder and dipping a wing, almost wetting it in the spray of a
breaking comber, he flung his airplane into a new line of flight,
reversed controls, giving opposite rudder and aileron, got his craft on
a stable keel and gave it the gun as he snapped up the flippers to lift
her nose and climb after the retreating 'plane.

Far behind them in their swift chase, with every ounce of power put into
their engine and their whole hearts urging it to better speed, the Sky
Patrol saw the amphibian swerve toward shore and give up the try for
whatever that precious life preserver had attached to it.

That something had been cast overboard, tied to the float, was obvious
to Larry, Dick and Sandy.

Nothing else explained its employment.

What a chase! Speed was in their favor, because the seaplane, fast as it
was, lacked the power of their engine which they learned later that Jeff
had selected for that very quality.

Overhauling the seaplane was not the question.

Their problem was to get above it, to ride it down, force it to take the
sea or to come down in a crackup on shore if that must be--before it
could lose itself in that dull, gloomy, lowering bank of fog ahead.

For that fog the seaplane was making at full speed.

"Climb, Jeff!" Sandy begged, hoping their pilot could ride down the
craft ahead.

But Jeff held a level course. He had to, in order to maintain the
advantage of speed. He thought he could get alongside their quarry
before the mist swallowed it, hid it, ended the pursuit.

In that he was beaten by only a hundred feet.

Into the murky folds of the thick mist dived the seaplane.

Hardly more than two hundred feet behind, they felt the cold, clammy
fingers of the cloud touch their shrinking faces.

Jeff cut the gun.

They strained their ears.

Where was the seaplane? Would it climb above the murk, glide straight
through it and down, swerve and glide--or dive out and risk leveling off
and setting down just beneath the bank so that its rapidly coming folds,
and the silent sea would make a safe and comfortable concealment?

Slowly, almost in a "graveyard" glide, so flat was the descent, to hold
flying speed and stay as high as they could, their airplane moved along.
They listened.

Only the raucous cry of a seagull cut into that chill silence!

The fog kept its secrets.

"This can't last long, for us," thought Larry. "We'll be down to the
water before we know it!"

Much the same idea made Dick peer anxiously over the cowling.

"They must be listening for us, in the seaplane," Sandy decided. "I know
there was a pilot and the man who got the life preserver. I wish I could
have gotten a good look at either one, but the pilot had goggles and his
helmet to hide his face and the other man had his back turned to us.
Where can they be? What are they doing?"

They could not wait for the answer.

Through a thin cleft in the heavy mist, not far below them the dark
outlines of eel-grass, flanking two sides of a channel in the swampy
shore line stood out, for an instant, clear and menacing.

"Jeff!" warned Sandy.

Dick echoed the cry. Jeff had already caught the threat of that swamp
below them. They could not risk going a foot lower. The pilot opened his
throttle, picking up climbing speed to the roar of his engine.

"We had to give in first," Larry decided ruefully.

Not only had they given in. Jeff, it appeared, had given up. In
thickening mist the risks were too great.

They had given up.

Jeff was climbing for the top of the bank, where he could come into the
clear, get some idea of his location and return to report defeat to the
yacht whose captain probably lay-to, waiting for news.

Nor did Jeff again cut the gun to listen.

"Oh, well," Dick was always hopeful, "maybe we'll get a 'break' sooner
or later."

Up, and still climbing, the airplane continued through the fog.

Low banks favored them.

With suddenly thinning rifts parting overhead they shot out into the
clear sunlight. Beneath, stretching up disappointed fingers of murk lay
the bank of fog.

"Look--toward shore!" screamed Sandy.




                               CHAPTER VI
                          THE END OF THE CHASE


Instantly the situation became clear to the Sky Patrol.

Having heard their own engine, the pilot of the seaplane had decided to
risk a dash out of the fog and to try to escape.

Their own airplane had been headed south, down the coast.

When they climbed above the lower shoreward mist the cry from Sandy drew
their attention to the seaplane, even higher than they were, and going
fast across the narrow end of the island.

"Now we can catch them and ride them down!" exulted Dick.

Jeff dropped a wing sharply--kicking rudder at the same time. Onto the
trail swung their craft. Righting it Jeff gave the engine all it would
take, climbing.

"They're getting ahead--getting away from us!" cried Sandy.

Larry, more conversant with flying tactics, decided that Jeff meant to
get to a higher level than they occupied, to outclimb the less flexible
seaplane, so that he could swoop upon it with the advantage of elevation
to help him overtake it.

Into the thousands their altimeter swung its indicator.

Three thousand feet! Another five hundred! Four thousand!

"Now we must be higher than they are!" Larry muttered. "Jeff--for
crickety-Christmas' sake--catch them!"

Jeff leveled and their engine roared. In a quartering course, evidently
making in an airline for some point on the Connecticut side of Long
Island Sound, the seaplane held its way.

Gaining in a very flat descent, calculated, as Sandy could see, to bring
them either alongside or--if fortune favored them--onto the tail of the
other craft, Jeff drew closer.

The seconds slipped by. The North Shore was almost under them.

Swiftly the distance closed up between the racing flyers.

"They're diving!" cried Sandy.

"Something's gone wrong!" Dick yelled. "She's out of control!"

The seaplane sheered to one side in a violent slip as her pilot
evidently tried to bank and kick rudder and lost control.

The seaplane wavered, caught itself in a steadier line. In the pursuing
airplane three youthful faces grew intent.

What was wrong?

"She's diving!" screamed Sandy.

"Something has happened!" decided Larry.

Down, almost like a hawk falling to its prey, the seaplane went through
the still air.

"Somebody's on the wing--he's jumping clear!" shouted Dick.

Trembling with excitement Larry caught up the binoculars. They were
still too far behind for clear vision unaided by glasses.

"He has that life preserver in one hand--there he goes!" cried Dick.

Silhouetted against the northern blue of the sky, with a tiny white
circle showing sharply in the sunlight, the leaping person fell clear of
the diving seaplane, while Larry, shaking with excitement, tried to
focus his glasses and train them on the falling object.

"He's harnessed to a parachute--there goes the ripcord!" Sandy would
have leaped to his feet but for his restraining safety belt.

"There goes the 'chute!" Dick was equally thrilled.

The parachute opened.

"The life preserver snapped out of his hand!" Larry muttered, giving up
his effort to locate the moving objects in the glass and using his
unaided eyes to view the tragedy--or whatever it would prove to be.

The life preserver was jerked away by the jar when the parachute
arrested the fall sharply, making it impossible for a handgrip to retain
the rope of the swiftly plunging white circle.

"Why doesn't the other one jump clear!" Dick's heart seemed to be
tearing to get out through his tightening throat. Which one was under
the parachute? Which stayed in the falling seaplane--and why?

An arm of mist, swinging far over the land, intervened between their
vision and the shore line.

Into it, hidden from sight, the seaplane flashed.

Through its concealing murk flicked the tiny round object of mystery.

More deliberately, settling down, first the hanging bulk of the unknown
man, then the spreading folds of the parachute drifted into mist--and
mystery.

The chase was ended.

But the mystery had hardly begun!




                              CHAPTER VII
                       THE SWAMP GIVES UP A CLUE


Two courses were offered to the Sky Patrol with Jeff.

"We can try to drop down into the fog," called Larry to Dick as their
pilot, with closed throttle, nosed down to get closer to the scene of
the tragedy.

"But we can't set down or do anything--and we can't see much for the
fog," objected Dick. "I think we ought to go back and drop a note onto
the yacht, telling the people to come here in a boat."

Larry agreed with this sensible suggestion and Dick, scribbling a note,
passed it to Sandy. After a glance the younger of the trio gave it to
Jeff. The pilot nodded when he read it.

Again the engine roared as they swung around, laying a course to take
them above the rolling mist, toward the end of the island around
which--or beyond which--the yacht should be cruising or waiting.

"It will be hard to find the yacht in this fog," Sandy mused, but as
they flew along he, with the others, scanned the low clouds for some
open rift through which to catch a possible glimpse of the water craft.
A slantwise gust of wind crossed the cockpits, giving them new hope. If
a breeze came to blow aside the mist they might have better chances to
see the yacht.

In steadily increasing force, and gradually coming oftener, the puffs of
moving air increased their confidence.

The fog was thinning under them, blowing aside, swirling, shifting.

With the breeze from the new direction, as they steadily got closer to
the end of the island, coming over a spot where a break in the cloud
showed brown-yellow sand and rushing white surf beyond the wide level
beach, Sandy's alert eyes caught sight of something for an instant.
Prodding Jeff, he indicated the object.

As Jeff swooped lower, inspecting, Dick caught a good glimpse of the
tilted, quiet focus of Sandy's gesture.

"There's the amphibian," Dick muttered. "Stranded--cracked up, maybe.
But--if we could get down and land, we could use her, two of us could,
to go to the swamp and see what's there--before anybody else gets to the
life preserver the jewels must have been tied to."

He passed forward, through Sandy, a note.

Jeff agreed, made his bank and turn, as Sandy saw the drift of a plume
of smoke on the horizon, to get into the wind.

Coming back, dropped low, Jeff scanned the beach.

"It looks safe for a landing--pretty solid beach," Larry concluded, and
evidently Jeff felt the same way for he climbed in his turning bank, got
the wind right and came down, using his engine with partly opened
throttle to help him settle gradually until the landing wheels touched
when the tail dropped smartly, the gun was cut, and the sand, fairly
level and reasonably well-packed, dragged them to a stop.

Hurriedly the youthful Sky Patrol tumbled onto the sand, digging cotton
plugs out of their ears now that the roar of the motor no longer made
them essential.

"It's the amphibian, and no mistake!" Larry cried, running down the
beach toward the titled craft.

"If she isn't damaged," he told Dick, "you and Jeff, or Jeff and I could
fly to the swamp in her."

"You go." Dick was generous to the friend he admired, and who was almost
a year older. "It would need a cool, quick head to handle whatever you
might find in the swamp. You go."

That also was Sandy's opinion when, after a rapid inspection, they
agreed with Jeff that the amphibian, set down with only a strained tail
skid and a burst tire in the landing wheel gear, was usable.

"But there's no gas," objected Larry, noting the indicator in the
control cockpit. "See, the meter says zero!"

"It was that way when I looked before," Sandy said. "That was why I
didn't think anybody meant to use it----"

"Easy to fool you on that," Jeff declared. "It's been disconnected. I
wouldn't be surprised if that-there tank wasn't nearly half full. They
had it all fixed and ready----"

"Let's go, then," urged Larry. "Dick, look over the pontoons for
strains, will you? She may have struck one of them--she has tipped over
part way, maybe hit one of the pontoons."

Dick, examining with the thoroughness of an expert, with Jeff's and his
chum's life perhaps depending on his care, stated that he saw no damage
to the waterproofed coverings of the water supports. Declaring that they
would stand by and watch the airplane, Sandy and Dick watched Larry and
Jeff get settled, Dick spun the propeller to pump gas into the still
heated cylinders, Jeff gave the "switch-on--contact!" call, Dick,
pulling down on the "prop," sprang aside to avoid its flailing blades,
and the amphibian's engine took up its roar.

Acting as a ground crew, Dick righted the craft by thrusting up the wing
which was evidently not seriously damaged, while Sandy, as the motor
went into its full-throated drone, shook the tail to lift the skid out
of the clogging sand. His eyes shielded from the sand, blasted back by
the propeller wash, he leaped sidewise and backward as the elevators
lifted the tail and the amphibian shook itself in its forward lunge,
lifted, flew within two inches of the sand, and then began to roar
skyward.

"He's drawing up the wheels, now," Sandy called to Dick.

"They won't be any good, with that burst tire--he'll have to set down in
water anyhow," Dick explained. Sandy nodded.

Waving to his two watching comrades as they grew smaller to his peering
eyes, Larry turned his attention to the work of scanning, from the
forward place, all the indented shore line, north, that the mist had
uncovered.

To their left, as they sped on, the lighthouse poked its tower out of
the drifting, dispelling fog.

Soon Jeff dropped low, diminished the throb of the engine, cruising
while Larry kept watch.

"Yonder it is!" Larry's hand gestured ahead and to the side.

Jeff, peering, located the wing of the seaplane, the fuselage half
submerged in muddy channel ooze, the tail caught on the matted
eel-grass.

In the mouth of a broad channel they touched water and ran out of
momentum with the wings hovering over the grassy bank to either side.

"Now what?" demanded Jeff. "We can't go in any closer."

Already Larry had his coat and shoes off. Stripping them off, and with
no one to observe, removing all his clothes, he lowered himself onto a
pontoon and thence to the water, chilly but not too cold on the hot June
afternoon.

Striking out with due care not to get caught by any submerged tangle of
roots or grasses, Larry swam the forty feet.

"The pilot's in his cockpit--" he gasped. "He's--he isn't----"

"Get that collapsible boat on the back of the tank, there!" urged Jeff,
"and come back for me."

It took inexperienced Larry some time to open and inflate the tubular
rubber device used for supporting survivors of any accident to the
seaplane while afloat.

"He's--I think he's alive," Jeff declared fifteen minutes later. "That's
a bad slam he's had on the forehead, though." He lifted the silent
pilot's bruised head, put a hand on his heart, nodded hopefully and bade
Larry dash water in the man's face.

The cold, salty liquid seemed at first to have no effect.

"He must have hit himself trying to get out," Larry surmised.

Jeff shook his head.

"His parachute isn't loosened or unfolded," he responded, working to get
the spark of life to awaken in the man he bent over. "No, Larry, from
the looks of things--somebody hit him, while they were away up in the
air, and jumped--with that life preserver."

"Where is he now? If only I could get my hands on him. I wonder who it
was?"

Jeff paid no attention to Larry's natural anger and wonder.

"He's coming around--fella--who did this-here to you?"

The eyes fluttered open, the lips trembled.

Larry, clinging to a brace, his feet set on a strut, bent closer.

"What happened? Who done this?" repeated Jeff.

The man, before he sank again into silence, uttered one word--or half a
word:

"Gast--" he muttered.

"Gast--was it somebody named Gaston?" asked Jeff.

The man did not respond.

"Never mind," Larry urged. "Can you get him into the boat, somehow,
Jeff? You ought to land him at a hospital--or at the nearest airport.
There's a medical officer at every one--for crack-ups. Or, fly and
telephone for help!"

"Would you be afraid to stay here if I take him to an airport?"

"No!" declared Larry, stoutly.

Without further words or conscious movements from the silent pilot they
managed to get him unhooked from his belt and parachute harness, to
lower him, precariously limp, into the rubber boat, which Larry held
onto as Jeff, half supporting his inert co-pilot, propelled it to their
own craft.

As they moved slowly along Larry, fending off a clump of tough grass
into which the breeze sought to drift their rubber shell, caught sight
of something dimly white, far in among the muddy grass roots.

He left his support, swam across the smaller channel, carefully, and
secured the life preserver which had dropped into a heavy clump of the
grass and then had floated free of the mud, held only by the end of a
tangled string--and the skin of an empty, oilskin pouch, torn and ripped
to tatters, that hung to the cord.

When Larry rejoined Jeff, he flung the life preserver into the space
behind the control seat of the amphibian, leaving it there without
comment as he helped Jeff to lift and drop the still unconscious man
into his own forward place.

Then, pushing off in the rubber boat, he sat still, his dry clothes in a
compact bundle in the boat thwarts, while Jeff let the wind and tide-run
carry his amphibian out of the channel to where he could get sea space
for a start, to get the amphibian pontoons "on the step" from which,
with his silent cargo of human tragedy, Jeff lifted into air and went
out of sight, southbound.

Sitting until he dried, Larry donned his garments.

"Gast--" he murmured. "Gast----"

Had he heard any name around the airports like Gaston?

"Well," he reflected, "its something, now, anyway. We can look for a
Frenchman--and learn if there's one named Gaston."

He sculled back to get under the shading, up-tilted wing of the
seaplane, studying what he saw of its half submerged after place.

"Glory-gosh!" he exclaimed, staring.

There, neatly arranged, was the row of chewed bits of gum!




                              CHAPTER VIII
                        SANDY MEETS A "SUSPECT"


"Hello, boys!"

Sandy and Dick, standing by the airplane on the beach, whirled to see a
short, stoutish man in regulation flying togs come unexpectedly into
view from behind an inshore hillock of sand.

"As I live and breathe!" the man continued, "I'm seeing things!"

His gaze was bent on the aircraft.

Sandy discerned instantly that he was looking at the pilot who had
handled the control job on the amphibian during the recent excitement.

The stranger had a pleasant, round face, with eyes that twinkled in
spite of the creases around them that showed worry. No wonder he was
worried, Sandy thought: having deserted the craft they had foiled in its
attempt to get the gems, the man had returned from some short foray to
discover his craft replaced by another.

"Howdy!" Dick greeted the stranger and replied to his exclamation. "No,
sir, you're not seeing things! At least you're not if you mean the
airplane near where the amphibian was----"

Sandy wanted to nudge his comrade, to warn him to be careful. There was
no chance; the man was observing them intently.

"Amphibian? You know the different types, eh? May I ask if you belong
around here, and if not, how you got here--and who took the 'phib'?"

Unable to check Dick, his younger chum had to stand, listening while
Dick related some of their most recent adventures.

"As I live and breathe! So you're two of the lads who were in the other
'crate'. Where's the third--and was that Jeff with you? I thought it
must be."

"Superstitions and all!" chuckled Dick.

Dick judged the man to be both friendly and "all right," from his
pleasant, affable manner and his evident knowledge of their pilot's
identity.

Not so Sandy!

His mind leaped through a multitude of theories and of suspicions.

This man might be "in cahoots" with Jeff, and Sandy was determined not
to take Jeff, or anyone else, at face value too readily.

The whole strange affair looked "queer" to him.

Jeff had falsified the true reason for the landing in the Everdail
field. He might falsify other things--his real reason for flying out to
the yacht. This man might be his partner in some hidden scheme. Even the
Everdail Emeralds, Sandy decided, might be just "made up."

"Nothing has been what it seemed to be," he mentally determined. "I wish
Dick would be careful what he says."

Since Dick had already given the man a sidelight on Jeff's character by
mentioning his superstitions, it occurred to Sandy that he might learn,
from the stranger's reply, how well he knew Jeff.

His expression, as Sandy watched narrowly, became one of amusement, he
smiled broadly, threw back his head and as he answered Dick's phrase
about superstitions and all, he laughed.

"He must have walked under a ladder, from the way things have turned
out," he said, amusedly.

"Who are you, please?" Sandy shot the question out suddenly.

"Me? Oh--" Did the man hesitate, Sandy wondered. It seemed to be so
before he continued. "I'm Everdail."

"Mr. Everdail?" Even Dick, questioning as he repeated the name, was a
little doubtful. "Why, I thought Mr. Everdail was in----"

"California? So I was. But one of my air liners brought me across in
record time."

Anybody could have learned that the millionaire was in California, Sandy
reflected; it would be easy for a clever jewel robber, one of a band, to
impersonate the man when he was caught off guard by their exchange of
aircraft.

"If you boys were with Jeff you must be all right," the man advanced,
hand extended.

Dick shook it warmly.

Sandy's grip was less cordial, but he played the part of an unsuspecting
youth as well as he could by finishing the handshake with a tighter grip
and a smile.

"I thought Jeff might be in the ship, yonder, until he nearly threw us
out of control with his propeller wash. Then I thought--he might be----"
he hesitated.

"He thought you might be--" Dick smiled as he made the response, winking
broadly.

Sandy wished his chum would be more careful.

The man who called himself Mr. Everdail nodded.

"As long as you're not, and I'm not--what neither of us cared to say,"
he turned toward the airplane, "let's get together! I'm here because my
passenger, a buddy of mine, wrenched his shoulder climbing back into the
'phib' and we set down here so I could leave him at the fishing shack,
yonder, and go back to see what was what. He was in too bad shape to
take chances if I felt called on to do any stunts--I thought I could
take the air in time to catch that seaplane coming out of the fog, but
it fooled me. I already know why you're here," he added, "suppose we hop
off in Jeff's 'crate' and give a look-see if your friend and my war
buddy need any help."

"You can't set down if they do," objected Sandy, his confidence in the
man's possible guilt shaken by his knowledge of Jeff's war record. "I
don't see, for my part, why Jeff didn't use the amphibian in the first
place!"

"I wondered about that when I got in at the estate, soon after you'd
left," Mr. Everdail--or the man who claimed to be the
millionaire--asserted. "I could see he had been working on it, getting
it ready--even had the tank full up, but he had disconnected the fuel
gauge to fool anybody who might be looking around, I guess."

"Maybe he landed and changed his mind about using it," Dick suggested.
"On account of taking us in--we organized a sort of Sky Patrol, to
oversee things--but everything went wrong."

"That accounts for it. I didn't know he was going to make the hop or I
might not have come myself--but now--well," the man broke off his phrase
and started to clamber into the control seat, "let's get going."

"And leave your passenger?"

"He's comfortable, lying quiet in the fishing shack."

Sandy, who had spoken, felt his suspicions returning at the reply. Could
there be any reason why they must not identify the other man? Might he
be the ringleader, or have some outstanding mark that they had seen
before and might recognize?

Dick performed the "mech's" duties for the pilot in getting the engine
started again, then he clambered into his old place. Sandy was already
behind their new pilot.

"Whoever and whatever he is," Sandy mused, "he knows how to lift a
'crate' out of the sand."

The man claiming to be Mr. Everdail made a skillful getaway from the
beach, and it took them very little time to get over the marsh, already
free of fog.

Dick located the crack-up, Sandy indicated the spot and the pilot
dropped so low that his trucks almost grazed the waving eel-grass.

"There's no amphibian in sight, though!" Dick murmured. "I wonder----"

"I see Larry! Yoo-hoo!" Sandy shouted.

Larry, in his rubber boat, just having given up trying to explain how a
number of bits of chewing gum had transferred themselves from the
amphibian, where last he saw them--or some like them--to the seaplane,
gestured and pantomimed to try to tell them his news.

Flying past they could not fully understand.

The new pilot waved a reassuring glove at Larry and swerved back toward
the end of the island. Larry wondered who he was and what his comrades
were doing with him; but Larry, always practical, let the questions wait
for their eventual answers and continued to study the half-sunken
seaplane.

No new clues offered themselves. He detached one of the hard, adhering
chunks of gum and dropped it into his pocket, "just in case," he said,
half-grinning, "just in case they transfer themselves somewhere else.
I'll leave twenty-nine of them--and see."

The supposed Mr. Everdail scribbled a note which he handed back to
Sandy, who caught his idea of dropping instructions on the deck of the
yacht.

Borrowing Dick's jackknife for a weight, Sandy prepared the message.

Cruising slowly the yacht came into sight.

Their pilot was skillful at coursing in such a direction and at such a
height that he could skim low over the water craft's radio mast and come
almost to stalling speed while Sandy cast the note overside.

Dick, who had caught up Larry's abandoned binoculars, saw as they zoomed
and climbed that a sailor had rescued the note before it bounded over
the cabin roof and deck into the sea.

At once the hydroplane was manned and sent away, the yacht took up its
own course, and Mr. Everdail--to give him his own claimed title--pointed
the airplane's nose for his estate. Sandy occupied the time of the
flight by trying to piece together the strangely mixed jig-saw bits of
their puzzle--or was it only one puzzle?

By the time they sighted the hangar and field, he had all the bits
joined perfectly. Sandy's solution fitted every point that he knew, and
was so "water tight" and so beautiful that he landed with his face
carrying its first really satisfied, and exultant grin.

The beautiful part of it, to Sandy, was that he could sit by and watch,
do nothing, except "pay out rope and let them tie themselves up in it."

For Sandy's suspects would certainly incriminate themselves.

"Let them guy me and call me 'Suspicious Sandy,'" he murmured as he
followed Dick toward the wharf on the inlet by the shore of the estate.
"If I untangle this snarl the way I expect to, I may not bother to go in
for airplane engineering. There might be as much money in a private
detective office."

Mr. "Everdail" proceeded at once to tie himself in his first knot.

"Well--hm-m!" he remarked to Dick, "feels good to be on the old place
again. First time I've set foot on it for three years."

"And he told us, on the beach, he'd been here this morning," Sandy
whispered to himself.

He decided to pay out another bit of rope.

"Mrs. Everdail will be glad you're here when she lands," he remarked.

The man whirled, frowning, hesitated and then spoke very emphatically.

"Look here, boys," he said earnestly, "don't say a word to her about me!
I won't be here when she lands--and I don't want it known I'm in the
East. There's a good reason----"

"I'll bet there is!" Sandy said to himself.




                               CHAPTER IX
                        JEFF ENCOUNTERS A "JINX"


Turning with a confidential air and addressing Dick, for whom he seemed
to have the greater liking, Mr. "Everdail" spoke.

"I've just thought of a good scheme. Has Jeff--er--taken you into his
confidence any?"

Sandy, helpless to interfere, heard Dick give the substance of what they
had learned from the superstitious pilot. The man continued:

"That lets me snap right down to my plan. Now we don't know where those
emeralds are. We don't know which people used the seaplane, or whether
the man who jumped has them and has gotten away or not. But if I should
fade out of sight, and no one but my dependable Sky Patrol knows I'm
around----"

"Your dependable Sky Patrol!" Sandy thought. "Going to try to use us
now. Well----"

"If no one else knows I'm around--I can watch and see a lot that others
might miss. I'm going to have that seaplane brought here--and then I'll
be around, watching to see who comes snooping--if anybody does. As I
live and breathe, I think that's a great idea, don't you?"

Dick agreed readily.

"All right, then. You can tell your other comrade--Larry, you said you
call him, Dick. I'll leave a note for Jeff. Now I'll go on up to the
house and write it and make a couple of telephone calls--and then I'll
drop out of things--but you'll hear from me off and on till we get those
emeralds safe in our hands. Then--even while we're waiting--if you can
get your parents' consent to stay, which I think can be arranged by
Jeff--Larry can take some flying navigation--you, Dick, can study
engines and construction, or navigation--whatever you like."

He put a hand on Sandy's shoulder and the latter managed not to wince or
draw away.

"Sandy can have the run of my library, full of books on engineering and
mechanics--and you'll be learning while you help me get those emeralds
and find out who flew the seaplane and who helped them on the yacht."

"I know I can get my father's consent to 'visit you' here," Dick said
eagerly. "And I like the plan," he added heartily.

Sandy, watching their confidant stroll toward the closed mansion, turned
a cold face to Dick.

"You're a fine Sky Patrol," he grumbled. "You swallowed everything he
said, like a big softie! And told him everything you knew," he
continued, bitterly.

"Why not?" Dick wanted to know.

"You wait till Larry comes and I tell him my theory!"

"All right," Dick agreed cheerfully. "But don't start in earning your
nickname all over again," he warned.

"I'll have you calling me 'Successful Sandy' before I'm through."

The drone of an incoming airplane took them racing to the landing spot
where Jeff came down to report that he had taken the unconscious
seaplane pilot to a hospital where it was declared that he had a bad
blow on his temple and might not recover his mental clearness for many
days.

"And I'm glad I'm done with this-here amphibian," he added. "Had more
trouble than I ever had before. I think the crate's hoodooed."

"Maybe the ghost haunting the hangar 'put a spell' on it," Dick
chuckled. "Well--don't, worry, Jeff. You're down safe, and----"

Sandy shook his head. Let them take Jeff up to the house, he decided,
and watch the two men when they met. Dick, not comprehending the idea
behind Sandy's headshake, nevertheless, did not finish his sentence.

The roar of a motor boat began to attract their attention and as they
went to the wharf again, Jeff wanted explanations of how they got in
with the airplane.

"You won't make me believe Dick flew that-there crate," he declared.

"No," Dick agreed. "I didn't. You'll find the man who did up at the
house."

Jeff swerved aside on a graveled path, leaving them to aid the caretaker
and his mechanic to bring the hydroplane to its mooring and let Larry
jump out to join them.

They compared notes eagerly. Dick and Sandy could hardly forego
interrupting one another as they brought their story up to the minute
after hearing how Larry had helped to get the pilot to the amphibian,
discovering and rescuing the life preserver on the way.

"Now, Larry," Dick said, finally, "Mr. 'Everdail' said we could take you
into our confidence, and he's probably telling Jeff everything.
Suspicious Sandy has a theory all worked out. I suppose Jeff is a
double-dyed villain, and this Mr. 'Everdail' will turn out----"

"It's no joking matter," Sandy spoke sharply. "You listen to my idea and
see what you think."

Jeff, the so-called Mr. "Everdail," and the pilot and passenger of the
seaplane, as well as the presumably injured man whom they had not
seen--all these were members of an international band of robbers, Sandy
claimed.

"The man who jumped with the parachute and life preserver must be named
Gaston--from what the pilot said to you, Larry," he went on.

"Then he must be French, maybe," Dick said.

"Most likely he is," agreed Larry. "But if he was----"

"Wait till I get to that," urged Sandy. "Well, they learned, somehow,
that Mr. Everdail was in California and his wife was taking the emeralds
to London. They didn't have any conspirator on the yacht--then--or else
they would have gotten the real emeralds long ago. So there was just
those five in the band--Jeff, Mr. 'Everdail,' Gaston, the man we haven't
seen, and the injured pilot."

"There might have been two gangs, one of three, one of two--or three
bands--one of two, one of two, one of one----"

"Don't poke fun at him, Dick. He argues reasonably so far."

"Thanks, Larry," Sandy was grateful. "All right, then, the band planned
the work in London, at the hotel--that's how Jeff knew the emeralds were
imitations they poured acid on."

"Did they carry acid just in case?" Dick could not restrain his tendency
to tease.

"I think it was something they meant to throw on anybody who tried to
stop them."

"Golly-gracious! That might be," Larry exclaimed.

"Anyhow, they discovered the false emeralds and tried to destroy them."
Sandy was more confident at Larry's acceptance of his ideas.

"They managed to get somebody on the yacht," Sandy guessed, "and then to
be sure that there was no hitch, divided into three groups--Jeff,
possibly the ringleader after all, in his airplane, two in the seaplane,
the other two in the amphibian."

"The confederate on the yacht was to secure the gems, somehow, and they
must have had a radio somewhere to get messages," Larry was beginning to
see daylight and to concur with Sandy's opinions.

"Yes," Sandy nodded, "and they all went to the appointed place----"

"But Jeff interfered with the amphibian," objected Dick, "and you forget
to account for the two men in the hydroplane."

"I think it came out the way it does in books," Sandy declared. "Each
set wanted those emeralds, and they tried to outdo one another--and
maybe the hydroplane was the honest one of the lot, with Mr.
Everdail's--the real one's--caretaker, summoned by the captain."

"But Jeff had us signal them," Dick said.

"They must know Jeff," added Larry.

"I know how that fits," Sandy spoke earnestly. "The hydroplane men were
honest, and Jeff worked into their confidence and offered to help
them--to discover the plan!"

"Well--that's possible," Larry admitted.

"We know what happened. Jeff signaled, but he knew the amphibian was
coming, and the seaplane, to make sure neither would break down and
leave him helpless--while he supervised," Sandy had good going now, "the
seaplane got the life preserver, and then Jeff decided that they might
get away, tried to follow--and while the seaplane was flying, its
passenger got the emeralds free of the life preserver, and then----"

"Now you're stalled," chuckled Dick, but Sandy was not defeated.

"The passenger, while they were high up, threw something and hit the
pilot, the seaplane went out of control, the man jumped--and then cut
free his parachute, cut the sack holding the emeralds, and hid in the
swamp."

"Why wouldn't he take the rubber boat?"

"It would be missed, Larry. He was too bright for that."

"How could he get away?"

"Why, Dick! Wait till everybody was gone, then take to the rubber boat,
get himself picked up----"

"If the boat isn't there when they bring up the seaplane, I'll think
you've hit the nail on the head," Larry conceded.

"I know I have."

"Sh-h-h! Here comes Jeff." Larry turned. "Well, Jeff----"

"He says you know all about him, but he was gone when I got this-here
note." He failed to display the missive, to Sandy's disappointment. It
would have provided a fine chance to compare the writing with what he
had seen in the letter supposed to have come from California. And--if he
was really flying East, why had Mr. Everdail written? A letter, by mail,
would be slower than an airplane flight!

"I don't like this plan a-tall, a-tall," Jeff went on, dubiously. "That
seaplane is jinxed."

"Oh--pshaw, Jeff----"

"I don't care, Larry. Listen--she cracked up and her pilot got a bad
smash--from something! And--the emeralds vanished!"

"We recovered the life preserver, anyhow," chuckled Dick. "And here
comes the yacht so we can return that much property. I tell you, the Sky
Patrol has accomplished something!"

Jeff did not share Larry's smile. He imitated Sandy's scowl.

"He says for me to shove my crate in the hangar, stay here, get your
parents to let you make a visit and Larry learn flying and so on, but if
I put my crate in that hangar--it haunted and now the jinxed seaplane to
come in--any instruction I give will be at your own risk."

"I'm not worrying," Larry said.

"And say--here's a queer one." Jeff changed the subject. "I notice them
chunks of gum wasn't in the amphibian! Did you take 'em out when you
stayed back in the hangar, Sandy?"

"No--or, if he did, somebody else put the same kind in the seaplane." As
Larry spoke he withdrew from his pocket a dark, hard object.

"Give that here!" cried Sandy, snatching at it.

He tore at the hard substance with finger-nails, working it flatter, and
then, with an exultant screech, boy-like but not good practice for an
amateur detective, he pointed to something dark, green, glowing.

"There's one of the Everdail Emeralds!" he exulted.




                               CHAPTER X
                            LARRY'S CAPTURE


"How did you ever guess the gem was in the gum?" Dick stared admiringly
at Sandy, exultantly at the green light flashing from that hidden
emerald as Sandy scraped aside the clinging substance from it.

"First the gum was in the amphibian," Sandy said, trying to be as modest
as the discovery would let him, "then it was gone. We thought we saw
somebody in the hangar when first we went in--but he got away somehow.
Then we saw the amphibian flying and it flashed over me that whoever we
had seen before had been working on the amphibian and had chewed up all
those pieces of gum--but I didn't see why he had left it there. Then,
when we found out that the man calling himself 'Everdail' didn't look
for or miss the gum, I guessed that he hadn't been the gum chewer--but
who had, then, I wondered. And why. It must have been for some reason,
because if he had found the gum when he came to play ghost, keep
everybody away from the estate by scaring them, and get the amphibian
ready, he'd have throw any gum he found into the waste can."

"The gum was there for some reason," agreed Dick. "This is one time when
being suspicious has paid," he added.

"Yes," Sandy admitted. "When the life preserver was found and no gems
were in the oilskin tied to it, and Dick showed me the gum, the reason
for the big chunks of old gum came to me. The passenger had been getting
it ready. He had to chew a great lot to get enough."

"We mustn't waste any more time," cried Larry, eagerly. "There are
twenty-nine more chunks in the seaplane. Let's fly there, Jeff, and get
it."

"That-there is good sense." Jeff started toward the flying field. "The
fellow we didn't find might come back for the emeralds."

Going with them, to help out, Dick told Larry that he proposed to go at
once to the various airports and flying fields, to learn, if he could,
who had engaged the seaplane.

"The new Floyd Bennett field is the best chance," argued Jeff. "They
have got water and seaplane facilities there. It's on Barren Island, and
that's where a man could have gone, in about the time between your
seeing the 'spook' and the time the seaplane got where the yacht was."

"I'll wait for the yacht," Sandy said, accompanying them. "Mrs. Everdail
will be glad to see what I discovered."

That gave each of the members of the Sky Patrol something to do.

Dick had no difficulty in learning, when he got the executives of
Bennett field interested that the seaplane was an old one belonging to a
commercial flying firm operating from the airport.

"The pilot who handled the control job," the field manager told him,
"was a stunt man who has been hanging around since he stunted on our
opening day. I've questioned some of the pilots for you, but no one
seems to know who the pilot had with him. A stranger, one says."

That brought Dick's quest to a dead stop.

Sandy had even less success. Although in the short time since his
disappearance the supposed impersonator of Mr. Everdail could not have
gone far, he was not to be discovered by any search Sandy could make.

Farmhouses had no new "boarders." The house on the estate, searched with
youthful vim and alert thoroughness, revealed no observable hiding
places. Sandy finally gave up.

The arrival, anchoring and debarkation of its people by the yacht
allowed him to meet and to reassure Mrs. Everdail and Captain Parks.

Besides these two he met the almost hysterical French maid, Mimi, also
Mrs. Everdail's companion and cousin, who had traveled with her, a
quiet, competent nurse and attendant whose lack of funds compelled her
to serve as a sort of trained nurse for the millionaire's wife, who was
of a very nervous, sickly type.

In spite of everybody's relief when Sandy displayed the emerald, the
elderly trained nurse and companion insisted that Mrs. Everdail must
retire, rest and recover from her recent exciting experience.

Sandy, left alone, searched the hangar for an unseen exit, but found
none.

Landing the amphibian, at almost the same spot they had set down before,
Jeff looked around for the rubber boat they had left tied to a sunken
snag.

"I guess Sandy's ideas were right, after all," decided Larry as he saw
that the small water conveyance was not there. Sandy had claimed that if
the missing seaplane passenger had hidden during the recent search of
the seaplane, the boat would aid him to escape from the otherwise
water-and-swamp-bound place.

"If the rubber boat's gone," Jeff commented, "the twenty-nine other
emeralds of the thirty on the necklace--they're gone, too."

"I'll have to swim over again and see." Larry stripped and made the
short water journey.

"They're still here," he shouted across the channel.

Jeff, who had kept his engine idling, decided to risk a closer approach
in the amphibian whose lower wingspan barely cleared the tops of grass
clumps.

"I guess there aren't any snags to rip the pontoons," Larry assured him.
To get closer would save Larry many trips to and fro in the water.

"Fine!" Larry commented as the amphibian, moving cautiously, came close
enough for him to catch a rope and put a loop around the closest truss
of the submerged seaplane. Thus he was able to pass the chunks of gum to
Jeff, who had his clothes on and pockets for storage.

While the transfer was being made the amphibian's engine died with
unexpected suddenness.

"Golly-gracious!" Larry exclaimed, "I'll bet she's out of gas."

"Can't tell by the gauge." Ruefully Jeff upbraided his stupidity in
forgetting to see if they had to gas up before the take-off from the
estate.

"Now what's to do?" he wondered.

Larry, too, saw a number of difficulties--perhaps more than did Jeff,
because, from Larry's point of view, due to Sandy's suspicion of the
superstitious pilot, Jeff must not go free with the gems in his pockets,
nor did Larry dare be the one to go. If he did, Jeff might be playing a
trick, let him get beyond chance of return in time, use some reserve gas
and fly away.

"I can't swim," Jeff began, considering the ways of escape to some place
where they could secure a supply boat with fuel.

"I wouldn't chance swimming all the way down the swamps to the nearest
village on shore," Larry said quietly.

"This-here is a fix that is a fix," morosely Jeff summed up the
situation. "Here we are with a pocketful of emeralds--and no gas and no
way to get to any--and if anybody knows the gems are in this gum--we'd
be helpless if they wanted to take them."

Larry did not answer.

He was mentally going over the seemingly unbreakable deadlock.

One thing that kept coming into his mind was the strange fact that if
the disappearing passenger of the seaplane had taken the rubber boat he
had not also taken the hidden jewels.

"He must have known something about them--or guessed," he reflected. "If
they were put in the gum while they were flying--unless it was done
while they were in the fog. But, even then, he knew all that excitement
meant something. I don't understand it--he did know, because he must
have hired the pilot and the seaplane to get the emeralds."

Still, in that case, he mused, if the man had known where the gems were,
why hadn't he inflated the rubber boat and taken them all, in the first
escape?

A possible solution came to him.

Saying nothing to Jeff he bent his whole power of thinking on the more
important discovery of a way to get fuel.

Climbing onto the amphibian and dressing, he considered that matter
without arriving at any workable solution.

His eyes rested for a moment on the upthrust wing of the submerged
seaplane. His face changed expression. An idea flashed across his mind.

"Jeff," he cried, "do you suppose we could make a gas line from the
brass tubing on the seaplane?"

"What for?"

"See that wing?" he pointed. "It sticks up, and it's higher than our own
tank--and if there's a wing-tank, and I think a seaplane would have
them----"

"Why didn't I think of that?" grinned Jeff. "I wouldn't be surprised if
that-there is right."

He carefully climbed out onto the amphibian's lower wing till he could
grip a guy wire on the seaplane. By agility and a good deal of scuffling
with some damage to the doped fabric of the seaplane, he got into the
partly sunken pilot's seat and from that, climbing up, sent a quick
glance over the cockpit, tracing the fuel lines.

"Right as can be!" he called. "Now if I can find a wrench and get loose
some brass tubing----"

"Can I help?"

Jeff, bent down in the pilot's seat, lifted his head, shaking it.

"Stay where you are," he called. "Two might push the crate down into the
mud too fast for safety. She's half a foot deeper in than when we were
here before. I'll manage."

Shutting off the governing valve, Jeff began unscrewing the pipe lines,
rejoining lengths of piping until, with a section from the carburetor to
give the needed length, he passed over a makeshift path for the
wing-tank gas to flow by gravity into their own craft.

"All ready!" called Larry, bending the end of the line so its flow went
into the central tank of the amphibian.

Jeff opened the gas valve under the wing-tank.

"Here she comes!" Larry was exultant.

"We'll get enough to hop down the shore to a fuel supply, anyhow," Jeff
said.

The gauges were out of commission and they had to figure the amount they
secured from the size of the pipe and time that the gas flowed.

"I guess that's all--about seven gallons," said Jeff as the last drops
fell into their tank. Larry threw aside the useless pipe, sent home the
tank cap and dropped down into the after seat to be sure the ignition
was off before Jeff swung the propeller sturdily to suck the gas into
the cylinders.

So intent had they been on the business of the gas transfer that as Jeff
swung the "prop" both were taken by surprise when a curt voice came from
close under the amphibian's tail assembly.

"Put your hands up--both of you! Quick!"

A man, coming silently from some concealment, in a dory, undetected in
their busy absorption, held something menacingly businesslike and
sending sun glints from its blue steel. Its hollow nose covered both at
the range he had.

Up went Larry's hands. Jeff, also, elevated his own.

"Now!" remarked the stranger, pulling the dory around without losing his
advantage, "both turn your backs and clasp your hands behind you!"

"Wait!" said Larry, suddenly, earnestly. "I'll give you the jewels
without making any trouble--if you'll let me put my hand in my pocket
I'll throw the emeralds down to you."

The man stared, amazed, either incredulous or not quite understanding.

Larry had no emeralds and was well aware of it. Jeff still made his
pockets bulge with the packed chunks of gum.

But Larry had seen a chance that they might turn to their own advantage
if once the man's eyes could be diverted from Jeff. Just before he had
clambered onto the forward bracing to spin the amphibian's propeller,
Jeff had laid down the sturdy wrench he had used for bending the pipes;
evidently he meant to transfer it to his own tool kit but had wished to
start the amphibian's engine first.

The wrench, within his reach, could be used as a weapon. Larry had
caught Jeff's flash of the eyes toward it as his hands had been
elevated. From Jeff's expression Larry saw, out of the corner of his
eye, that the older pilot caught the younger comrade's purpose.

"All right," the man had recovered his surprised wits and was closely
watching Larry. "Which pocket?"

"This one!" Larry, carefully keeping fingers spread wide, tapped one
side of his coat.

"Throw the package or whatever it is----"

Jeff's hand was quietly coming down.

"It's stuck!" Larry began to tug, with his hand in his inside pocket
where he pretended the jewels were.

"No monkey shines!" warned the stranger, watching closely.

Jeff's hand flashed down, the wrench, with a twisting, underhand fling,
spun through the air. Jeff dropped into the cockpit. The wrench struck,
hitting the man's arm and deflecting the muzzle of his weapon as it
exploded--but he did not drop it.

In that split minute of time Larry was on the cockpit seat--and plunged,
in a swift, slantwise leap, down upon the man in the dory.

His unexpected assault was executed so rapidly that the man had not time
to recover from the surprise and get his weapon trained, before Larry
was on him, sending him sprawling backward.

"Oh--my shoulder!" the man cried out in sudden anguish.

Larry, startled, seeing the pain in the face just under his own, relaxed
for an instant, only being sure that his quick grip on the wrist holding
the weapon in its hand was not released.

"Oh!" the man groaned, and dropping his weapon, he began to nurse his
shoulder.

Larry suspected some trick, but there was none. The man tamely
surrendered. As he nursed his painful muscles, a sudden misgiving came
over Larry.

The man, he recalled, in pulling with his arm, had winced, before he got
the dory where he wanted it. His cry, his subsequent favoring of his
shoulder, told Larry the truth.

"You're the man who was in the amphibian when Mr. Everdail flew it!" he
said. "How did you get here, with your injured shoulder?"

"Tide brought me through a channel. I felt better, saw a spare dory and
watched some debris on the water and reckoned the tide would get me to
where I could see where the amphibian set down. I saw it hop off the
beach, saw it disappear, heard it and saw it coming back--and was
curious--but how did you know about Mr. Everdail--and who was in the
seaplane, and in the other crate I saw?"

"Here comes the tug and floating crane, to salvage the seaplane," said
Jeff. "You'll have to stay in the tug deckhouse, till we get the
straight of this--and for holding a gun on us. You can explain to the
police, maybe--as for us, we don't need to explain!"

And, as later, he and Larry resumed their places in the amphibian,
Larry's captive remained under guard on the tug.




                               CHAPTER XI
                        "POP! GOES OUR MYSTERY!"


Before the lowered landing wheels of the amphibian touched the private
landing field, after a flight delayed by the need of more fuel, Larry
saw his chums waiting by the hangar.

As the aircraft taxied to the end of the runway he saw that their
expressions were doleful.

"Bad news?" Larry asked, climbing to the turf.

"Our adventure is over and done with," Dick said. "It has gone 'poof'
like a bursted soap bubble."

"But Jeff and I have caught the man who was with the one claiming to be
Mr. Everdail----"

"Claiming to be," Sandy said disgustedly. "I was wrong. He _is_ Mr.
Everdail."

"How did you find out?"

"He came back, Larry." Dick chuckled.

"Came back? I thought----"

"He wrote the note for Jeff, and then called up the hospital where the
pilot was taken," Dick stated. "They said the man seemed to be coming
out of his sleep and Mr. Everdail went out to the road while we weren't
especially watchful, and got a passing car to take him to the next
village. Then he took a taxi to the hospital."

"And what he heard there made him come home," Sandy added.

"What did the pilot say?"

"You recall what you thought was part of a word?"

"Yes, Dick--the beginning of 'Gaston,' we thought."

"Larry--it was a whole word."

"Gast?----"

"It sounds the same, but if I spell it you'll see."

Slowly he spelled a word of six letters.

"G-a-s-s-e-d."

"Gassed?"

"Carbon monoxide--deadly fumes that blew in from the exhaust of the
engine--it was an old crate, and the engine didn't have perfect
combustion, he said," Sandy gave the explanation.

"The direction they flew," Dick added, "across the wind--the fumes blew
into his cockpit. It was set low, you know. Well, before he knew what
was what, he felt himself going. Then he thought he could snap out of
it, loosened his safety belt, tried to lift himself for a breath of pure
air--the seaplane dived, and he fell against something that knocked him
out!"

"Then the passenger didn't----"

"No. He didn't throw anything. The pilot explained all that," Dick said,
while Jeff formed an interested fourth of the group. "You recall, Jeff,
the captain of the yacht took out extra insurance on the emeralds?"

"I remember that, too," Larry said.

"The English company became suspicious," Dick went on. "They sent a
man--we've called him 'the passenger'--to this side, suspecting that
some effort was on foot to hide the gems or get rid of them till the
insurance was paid--it's a trick that has been worked."

"I begin to understand," said Larry. "The man from England hired the
stunt pilot to fly him out to meet the yacht--but how did he know when
it would arrive?"

"Can't you guess?"

"I can," said Jeff. "That English fellow was that-there 'spook.' Maybe
he 'listened in' on the short wave set in the big house yonder."

"That's probably it," Dick retorted. "Anyway, he flew out, and when he
saw the amphibian and the small hydroplane and our airplane, he jumped
to the idea that either one or more gangs of robbers had somebody on the
yacht to get the jewels and throw them out, or else----"

"Wait!" urged Larry. "How does the gum fit in with that?"

"That's so," said Dick. "Let's go up to the house and see what Mr.
Everdail says."

"If he is Mr. Everdail, after all," Larry said.

"Oh, his wife would know any impersonator," argued Dick. "So will Jeff."

"That's so. Come on."

That the millionaire was genuine, "in person and not a caricature," as
Dick put it, was evident. Both the nurse, his relative, and his wife,
were chatting with him as Jeff delivered the heavy packed ball made up
of the gum.

"How about this-here?" he asked. "How does this fit in?"

"That's simple enough," responded the rich man, breaking the exhibit
into its separate pieces. "The special agent from England, watching
here, had seen Jeff making his nightly hops over from the airport. He
thought, quite naturally, Jeff was working with some jewel robbers."

"That doesn't explain this-here gum," objected Jeff.

"This will. The agent from London thought it likely that some attempt
would be made to get the jewels. He proposed to see whether it would be
made by professionals or by some one working for me. He thought my wife
or I had the intention of robbing ourselves--making the gems disappear
until we could collect the insurance. When he couldn't make up his mind
which was most likely--professionals or amateurs hired by us--he thought
of trying to get the jewels--and that meant----"

"A safe hiding place if he was followed, until he could get to a vault
and notify his firm," Sandy broke in, eager to declare how mistaken he
had been by giving the true facts.

"And how about the man who was with you?" Larry turned to Mr. Everdail,
while Mrs. Everdail with a little grimace of disgust, drew Sandy's first
discovery of the gem in the gum closer to look at.

"He's one of my divisional managers in the transcontinental tourist
airlines," stated the millionaire.

"Then we'd better get him off that wrecking tug," and Larry gave the
story of the man's appearance and capture, giving Jeff the credit which
Jeff, generously and promptly, returned to him with interest.

"Well," concluded Mr. Everdail, "here are the emeralds, minus the chain,
which can easily be duplicated. And you know who's who, and why the
hangar seemed to be haunted, and all about the gum. Is there anything
you don't understand?--before Larry starts taking flying instructions
from Jeff and you others join my wife and I for a cruise to Maine where
I will leave Mrs. Everdail."

"Yes, sir," Larry responded. "We saw that parachute the man in the
seaplane had come down with--the harness was unbuckled, so he wasn't
hurt in the drop. What I want to bring up is this: why did he desert the
stunned pilot--and not appear when we landed there?"

"I wonder," the millionaire was thoughtful. "I wonder what you would do
if you had to make a 'chute jump and then, after the excitement
discovered that the pilot was 'out' and had a blow on the temple--and
with concealed jewels in his cockpit----"

"Guess I'd hide too!"

"But why were the chunks of gum put in the pilot's cockpit and not in
the passenger's?" Larry persisted.

"You're getting worse than I am," grinned Sandy.

"The passenger was not an aviator," the rich man retorted soberly. "He
put them where he thought he would sit--in the wrong place, it happened.
So, when they got the jewels, it was simpler to put them where the pilot
could hide them, where the gum was."

"Another reason would be," Jeff said, "pilots use gum and it would look
more natural for it to be stuck around where he did his control job than
up forward, where the special agent had it in the amphibian."

"That's all that bothered me," admitted Larry.

"And Pop! goes our mystery," chuckled Dick.

Mrs. Everdail bent forward, and then looked up sharply.

"I don't know about that?" She turned to her husband.

"Atley," she said, excited and nervous. "Look here!" The man almost
raced around the library table, bending close to where her finger
touched the dark green showing through the adhesive gum.

"I don't see anything--out of the way," he replied to her look.

The Sky Patrol saw her expression and each grew taut with excitement at
her next words.

"Don't you see? Can't you?" She raised her voice to a shrill pitch of
excitement.

"I see one of the emeralds----"

"Don't you see that it is pitted--burned--by acid?"

"Glory-gracious-golly!" Larry was agitated enough to couple all the
exclamations.

"This isn't the Everdail Emerald," the lady was almost screaming, her
hands trembled as she pointed. "It is the emerald that I had in the
hotel room----"

"The imitation!"

"Yes, Atley! Oh----"

Dick turned to Larry.

"I just said, 'Pop! goes our mystery.'" He had to laugh in spite of the
grave situation, the new development, as he added:

"Well--'Pop!' Here comes our mystery back again!"

"Bigger than ever!" agreed Larry.

For once Sandy was absolutely speechless.




                              CHAPTER XII
                         THE HOODOOED AIRPLANE


After their exciting day, the next two weeks proved more than dull to
the youthful members of the Sky Patrol.

Nothing happened to clear up the mystery.

To the surprise of the yacht crew, Captain Parks kept them all busy
preparing, the day after Mrs. Everdail's dramatic discovery, for a run
to Bar Harbor, Maine.

That was unusual. After a trip across the Atlantic, the yacht was
ordinarily laid up for awhile, giving its crew some shore liberty.

Captain Parks, however, agreed with Mr. Everdail, who trusted him
absolutely--if Sandy did not--that it would be wise not to give any
person who had been on the yacht during its crossing any chance to get
away.

"On the run," Mr. Everdail told Sandy and Dick, "and while we lay over
at Bar Harbor, you two can watch for anything suspicious. My wife won't
let me say that Mimi, the maid, could be guilty--besides, how could she
get into Captain Parks' safe?"

"I think, myself, some man of the crew would be the one to watch," Dick
agreed. "Maybe the steward, who could have a reason for getting into the
captain's quarters."

"But it was a woman Larry saw, through the glasses, at the stern," Sandy
objected.

"Well, then--there's the stewardess who attends to the ladies' cabins,"
argued Dick. "We can watch her."

They did, but no one on board asked for shore leave, either on the day
before lifting anchor or during the stay in the Maine waters. Dick and
Sandy used ears and eyes alertly; but nothing suspicious looking
rewarded their vigilance.

Larry, staying at the old estate home with Jeff, had some compensation,
at least, for being separated from his chums. Not only could he keep an
eye on things and be ready if Jeff called for an aide; as well, he had
his daily instruction in ground school and in the air.

Already "well up" on all that books could tell about engines, types of
airplanes, construction methods, rigging and even handling a craft in
the air, he got the practical personal experience that is the only real
teacher, and the thrill of donning the Gossport helmet, with its ear
'phones and speaking tube through which Jeff, in the second place of the
amphibian or the airplane, instructed him, correcting faults or gave
hints, was a real thrill.

He learned, first of all, not to start up an engine while the tail of
the ship pointed toward a hangar, or other open building, or toward a
crowd, in future, on a field.

The propeller blast threw a torrent of dust and as Jeff told him, he
mustn't become that most unpopular of airport nuisances, a "dusting
pilot," whose carelessness flung damaging clouds on airplanes in hangars
and people on the fields.

Learning to warm up the engine, to check up on instruments, to keep the
ship level while taxiing down the field to head into the wind, to make
the turn, either in stiff wind or gentle breeze, so that the wind did
not tip the craft and scrape wingtips--these and a dozen other things he
acquired in several early lessons.

The second place of the airplane had been fitted with a set of dual
controls, rudder bar, throttle and "joystick" so that Jeff, for two
successive hops, let Larry put feet on his rudder bar and lightly hold
the stick as Jeff manipulated the controls and explained, by use of the
Gossport helmet, why he did this or that.

Jeff believed, as does every good instructor, that showing, and
explaining, is necessary as a first step, but that a flyer is developed
only by practice during which he makes mistakes and is told why they are
mistakes and how to correct them, thus gaining confidence and assurance
by actually flying.

"That-there time," Jeff might say, "when the caretaker 'playing
mechanic' and pulling down the prop till the engine catches, didn't you
open up the throttle too wide? Better to open it just enough to give the
engine gas to carry along on--and even cut the gun a bit more to let it
run fairly slow till it warms up. Turning her up to full eighteen
hundred revs don't gain while she's cold, and it throws dust like sin!"

Or, as Larry taxied, learning to manage speed on the ground by use of
wider throttle for more speed, cutting down the gas if the craft began
going too fast, he would catch an error:

"Did you forget last time to put the stick back and make the blast on
the elevators hold the tail down while we taxi? Sure, you did--but you
won't again, because you saw that if you didn't we might nose over. You
'over-controlled', too, and almost nosed over before you caught it--and
then, we were going so fast I don't know what kept this-here crate from
starting to hop.

"That's right--easy movements always--don't jerk the controls--take it
fairly easy. And you are doing right to move the stick back to neutral
this time when the tail came up--kick rudder a bit, isn't she slanting
to the right? That's it, buddy, left rudder and back, and now the right
rudder--there she is, headed right."

Mostly, Larry caught his own mistakes in time.

Ordinarily cool-headed, he had to be told only once or twice, and
reminded almost never that jerky manipulation of the controls was not
good practice or helpful to their evolutions. Easy movements, continual
alertness and a cool head stood him in good stead.

Seeing those fine qualities, Jeff had Larry thrilling and happy on the
fourth day by letting the youthful enthusiast for aviation take over for
a simple control job, straight, level flying.

"You'll want to get the feel of the air, and see how stable the average
modern crate is," Jeff spoke through the Gossport tube. "How does
that-there wing look to you--kind of dropping?--remember what I
did--that's the stuff, stick to the left a bit and back to neutral, so
the other wing won't drop! No use teetering back and forth. They put
neutral position into a control so you can set ailerons or rudder or
elevators where you want them and hold them."

There was more than Larry had ever dreamed there would be to keep in
mind: there was the maintaining of level flight; even in his simplest
personal contact with the controls; then there was the job of keeping
the horizon line at the right location by watching past a chosen spot on
the engine cowling, else they would start to climb or go into a glide.
There was the real horizon to distinguish from the false horizon, which
an airman knows is, through some trick of the air, the visible horizon
that is just a little bit above the true horizon, so that to hold level
flight in a forward direction, that false horizon is not held on a line
with the top of the engine cowling, but, to hold a line with the true
horizon the marking point is held just a trifle below that false,
visible horizon line.

Had that been all he had to comprehend Larry's first control job would
have been simple. There was much more to watch--the tachometer, to keep
track of engine speed; the air speed was learned by watching the
indicator on the wing of that particular type of airplane; the position
of the nose with relation to the horizon had to be constantly noted and
a tendency to rise or lower had to be corrected: little uprushes or warm
air made the airplane tilt a trifle to one side or the other and
ailerons had to be used to bring it back, the stick had to be returned
to neutral gently at exactly the point of level flight after such
correction and not sent to the other side or the craft tipped the other
way and opposite aileron had to be applied; then there was the chosen
point such as a church steeple, tall tree or other landmark selected as
a point on the course to hold the nose on--that must be watched and a
touch of rudder given if the craft deviated from its straight line.

Nevertheless, complicated as flying appeared to be on that first
handling of joystick, rudder and throttle, Larry knew that the happiest
time of his life would be his first successful solo hop, and that the
complicated look of the maneuvers and the number of things to
watch--level flight, direction, maintaining flying speed, seeing that
altitude was maintained, that his own craft was not menacing or menaced
by any other in the air, all these would become simple, second nature as
soon as the flying hours piled up and gave him more skill and
experience.

Morning and afternoon Jeff took him up.

Quick to learn, retentive of memory, not repeating the same
mistakes--even working out some points for himself--Larry, at the end of
the fifth day, was gratified to have Jeff, as he slipped off the
Gossport, tell him:

"The only trouble about this-here instruction is that I'm scared you're
going to make a better pilot than your teacher."

"Oh, thanks--but I never could be any better than you, Jeff."

"Yes, you can," the older man's face became doleful. "You ain't the kind
to let that-there superstition bug bite you."

"No," admitted his pupil. "I think superstition is just believing
something somebody else tells you until you are so busy watching out for
something to go wrong that you aren't 'right on the job' with your own
work--or you are so busy waiting for some good thing to 'happen' that
you don't see Opportunity when it comes up because you're not watching
Opportunity--you're watching Luck, or Omens."

"Don't I know it!" Jeff was rueful. "I want to kick myself
sometimes--but when you know other folks has had their crates 'jinxed'
by being in the same hangar with one that has got the name for being
hoodooed--what would you do?"

"Just what I'm doing now," Larry grinned. "I know Mr. Everdail paid the
company for the ruined seaplane and moved it into the hangar, here. I
know your airplane almost touches it, every night. But I don't let that
worry me, because----"

"Well, it worries me. I try not to let it, but the worry is there, no
matter what I do. You see, I never thought, out in the marsh, about
anything going wrong because I took that big wrench and put it in my
tool kit after we salvaged it out of the water. But I dreamt about
emeralds, last night, and so I went to a fortune teller gypsy woman and
she told me a dream like that meant bad luck in business, and so I said
I was a pilot and told her all about the seaplane----"

"You ought to be careful," Larry interrupted. "If she puts two-and-two
together, emeralds and a chase and a wrecked seaplane----"

"Oh, she was too busy talking to listen that close."

"They're awfully quick--the way they guess what's in your mind proves
that."

"Oh, she won't think anything about it. Anyhow, she told me not on any
chance to touch that cracked up seaplane or anything that ever was on
it--and so--I put the jinx on my own crate without meaning to."

"I'm still willing to learn in it."

"Well--I don't know--it worries me."

"It doesn't bother me, Jeff."

And it didn't, for several more busy days.




                              CHAPTER XIII
                          THE "HOODOO" STRIKES


"Hello, Sandy! How are you, Dick?" Larry met the returning chums as they
climbed to the small estate wharf from the yacht tender, and while they
strolled up the path he asked eagerly:

"Anything new? Anything suspicious?"

"Not even our Sandy could discover a thing," Dick confided.

"Those emeralds aren't on the yacht," Sandy declared. "Captain Parks
helped us by sending most of the crew ashore while Mr. Everdail took his
wife to their woods camp. We went over the yacht----"

"With a fine-tooth comb!" Dick broke in. "We did make one big discovery,
though."

Larry turned toward him quickly.

"What?"

Dick tried to conceal the twinkle in his eye, but it got the better of
him as he explained.

"We found a string of beautiful, perfect emeralds in the stewardess'
cabin, hung up on a nail."

"Honestly?"

"Positive-ully, Larry! The finest that ever came out of a ten-cent
store!"

"Oh--you----"

"Sandy suspected her right away!" went on the jovial one, "but no arrest
was made."

"What have you discovered?" Sandy asked Larry quickly, to cover his
impulse toward assaulting the teasing chum.

"Not a thing--except I learned that the injured pilot was able to sit up
and I went to see him." Dick and Sandy waited anxiously for a
revelation, but Larry was unable to give one.

"He is named Tommy Larsen," Larry informed them. "He's getting well
fast. He was glad that his passenger had been wrong in suspecting the
Everdails----"

"You didn't tell him the emeralds we found were the imitations?"

"No, Sandy. He thinks they were the real ones."

"What did he say to explain about his passenger not helping him, and
then taking the boat?"

"The man came while I was there," Larry told Dick. "He is named Deane,
and he's a nice-looking, quiet chap. It seems that when he landed with
his 'chute, he came down and struck some driftwood or an old log, and it
knocked the wind out of him. When he got back strength to cut himself
loose, he tried to get to the seaplane but his landing, as I explained
the location--well, you saw it when you flew over--his landing was made
a couple of hundred yards away. I got the gardener to take me to the
place, yesterday, in the hydroplane. There was a big, sunken log close
to the torn 'chute."

"Did he see you, that day?"

"No. He tried to swim over, turned sick, crawled onto some mud that was
out of water and stayed there. I guess he fainted. When he managed to
get there, we had taken Tommy Larsen away--so he's cleared!"

"I don't see that!"

"Why--Sandy! We left with the pilot--I mean, Jeff did. Then the
hydroplane came for me, and when he got there, afterward, don't you see
that if he was guilty of anything, he'd have taken the chewing gum?"

"He might have seen that one chunk was gone, suspected that the hiding
place was discovered and left the rest----"

"Suspicious Sandy!" Dick laughed. "With twenty-nine lovely emeralds to
recover--and a rubber boat to get away in!"

"All right! All right! He's an innocent man."

"As innocent as the man I helped capture--Mr. Everdail's friend, that
man we put on the wrecking tug for five hours."

"Everybody is innocent," declared Dick. "Sandy, my advice to you, for
your birthday, tomorrow, is to turn over a new leaf and instead of
looking for people to suspect, try to think where those emeralds can
be."

"They're not on the yacht, you say," Larry said to take away the sting
to Sandy's pride. "They aren't in the old house. They were taken from
the captain's safe--where did they go?"

"You tell me who knew the way to get into the captain's safe and I'll
try to get the emeralds."

"Captain Parks says no one ever was told that combination."

"All right, Dick," Sandy replied to the chum who had just spoken.
"You've answered Larry's question."

"Golly-glory-gracious! It does look that way!"

"Who else could be safer? _He_ says the emeralds were gone and _his word
is his bond! Oh, yes!_"

"Then the emeralds won't be found," concluded Dick. "Captain Parks has
been ashore, and away, hours at a time, here and in Maine."

"Let's see if Mr. Everdail won't listen to us about that, now."

Dick's suggestion was followed.

The millionaire listened gravely to their statement and broke into a
hearty laugh.

"As I live and breathe!" he said. "You members of Jeff's Sky Patrol are
working for the wrong side. You ought to be with that London lad, who
suspects my wife and her cousin, Miss Serena, and me! Oh--this is great!
You're helping me a whole lot. I think I must increase the allowances
for Suspicious Sandy, Detective Dick and--er--Follow-the-Leader Larry."

He turned his frowning lips and smiling eyes on the latter.

"I'm amazed at you, though. Jeff says you've got good judgment."

"Captain Parks had opportunity--he knew you would take his word--no one
else knew his safe combination. Isn't that common sense, sir?"

"It's a kind of sense that's common enough--but----"

"Who else could get the emeralds?" persisted Sandy.

"Well, let's see. Besides Captain Parks, there's--" his voice trailed
off; once he shook his head at some thought; once he scowled; finally he
shook his head defiantly.

"As I live and breathe--it looks--but I won't believe it! Not Billy
Parks. He's----"

"All right, sir," Larry said. "We thought we ought to report what came
into our minds. But we can't prove anything, of course."

"All right, my boy. Watch him, trail him, whatever you like. I'll give
you each a thousand dollars if you can prove----"

"How can we, unless we catch him--and the emeralds are gone----"

The millionaire swung on Sandy as the youth spoke.

"Wait--let me finish. A thousand dollars if you'll prove--Parks is
innocent!"

"Oh!"

He turned, dismissing them as he greeted his cousin, Miss Serena, who
had declared that his wife would be better off alone to rest in the
quiet camp in Maine. Miss Serena, with a will of her own, had come back,
determined, if the rich man proposed to stay at his old estate, that she
would assemble a group of servants and manage the house for him. The
three chums sidled out, neither of the three counting on the payment of
that, to them, large sum.

"There's money we'll never get," said Sandy.

The others agreed.

Sandy's birthday dawned hot, but clear, with a good, steady south wind
blowing.

The rich man had not forgotten Sandy. A fine set of books awaited him at
the breakfast table, a set of engineering books that he would prize and
study for many years.

Larry's remembrance, a radium-dial wrist watch, and Dick's gift, the set
of drawing implements he coveted, delighted him. Jeff's modest but
earnestly presented "luck charm" secured from his gypsy fortune teller
was accepted with a grave, grateful word--but Sandy had hard work not to
break into a wild laugh.

"How old are you, buddy," Jeff asked.

"Thirteen!"

Jeff's face grew sober.

"And this is Friday!" he murmured.

"Surely it is," laughed Larry, and then, in a lower tone, he urged,
"now, Jeff----"

"No, sir! I won't go up, today, even if you did plan to surprise----"

"You would spoil it!" Larry was unable to keep from being annoyed,
almost angry, because Jeff had spoiled a surprise.

"We might as well tell you, Sandy, now that it's 'all off'," Dick said.
"We were going to give you another present--a hop over your own house in
Flatbush--with Larry for pilot! But----"

"Oh, never mind Jeff. Let's go!"

"Don't be silly, Jeff," Mr. Everdail chided the pilot. "Check over
everything and then go up. You know mighty well that accidents don't
come from 'hoodoos'. They come from lack of precaution on the pilot's
part. The weather charts for today give perfect flying weather. The
airplane is in fine shape. Go ahead--give the lads a treat!"

"On your heads be it!" Jeff said somberly.

He did not neglect his duty. For all his nonsense about omens and such
things, he gave the airplane a careful checkup, warmed up the engine for
Larry himself and made sure that everything he could foresee was
provided for.

Sandy, thrilled at the prospect of a hop with his own comrade doing the
control job, was full of fun and jokes.

Dick, no less eager to see Larry perform his new duties, wasn't behind
Sandy in good humor.

Larry, though quiet, was both confident and calm.

He did not forget to assure himself, by a final look at the windsock
indicating the wind direction, that the breeze had not shifted.

Neither did he "dust" the hangar, nor lose his straight course as he
taxied across the field at an angle to turn, without scraping wings or
digging up turf with the tail skid.

A final test, with chocks under the wheels, the signal for the wheels to
be cleared by the caretaker, a spurt of the gun for several seconds to
get the craft rolling as the elevators were operated to lift the tail
free, a run at increasing speed, picked up quickly because of the short
runway--stick back, lifting elevators so the propeller blast drove the
tail lower and the nose higher--and they left the ground.

Stick back from neutral, after leveling off for a bare two seconds to
regain flying speed, and they climbed, the engine roaring, Jeff nodding
but making no comment through the speaking tube he still used. Dick
shouted a hurrah! Sandy joined him.

Over the hangar they rose, and Larry, holding a more gentle angle to
avert a stall, continued upward until his altimeter gave him a good five
hundred feet.

Then, choosing a distant steeple as in direct line with the course he
would fly toward Brooklyn, to be out of any airline around the airports,
he made a climbing turn, steadied the craft, straightening out, went two
thousand feet higher to be doubly safe--and drew back his throttle to
cruising speed.

"Who says this airplane is hoodooed?" shouted Sandy, jubilantly.

And then--the hoodoo struck!




                              CHAPTER XIV
                       DICK HANDLES A CONTROL JOB


Flying close to three thousand feet above Oyster Bay, level and stable,
the airplane seemed to be in perfect condition.

Jeff, for all his superstition, would have given it as a pilot's opinion
that only some mistake on Larry's part, or a quitting engine, leaving
them with a dead stick, could cause danger.

Just the same the unexpected happened!

"There's where President Roosevelt lies," Dick, in the last seat,
because their places were rearranged by Larry's position as pilot,
indicated to Sandy, just ahead of him, the cemetery beneath them.

Very tiny, in its iron fenced enclosure, the last resting place of a
national idol, was almost invisible with its simple headstone; but
Dick's statement was understood by Sandy to mean the location more than
the exact spot.

"I'll get Jeff to ask Larry to spiral down for a better look," Sandy
decided.

He transmitted the suggestion.

"Sandy wants to see President Roosevelt's place in the cemetery," Jeff
spoke into the tube of the Gossport helmet Larry still used.

"There it is, just off our left wing, buddy. That's right--stick goes to
the left and a touch of left rudder, but when you moved the stick
sidewise to adjust the ailerons you neglected that-there bit of forward
movement to tip us down into a glide. Remember, it's the double use of
the stick that works ailerons and elevators both."

Larry had overlooked that point for the instant. It was his only
difficulty in flying, to recollect always to control all the different
movements together. The joystick, operating the wing-flap ailerons by
the left-or-right, lateral movement, also raised or depressed the
elevators by forward-or-backward movement. However, in any lateral
position, the forward and backward set of the stick worked the elevators
and in executing a control maneuver, even as simple as going into a bank
combined with a turning glide, or downward spiral, the movement of the
stick should be both slightly sidewise, for sufficient bank, and, with
the same movement, slightly forward, for depressing the nose into a
glide, returning the stick from slightly forward back to neutral to
avoid over-depressing the nose into too steep a glide; if not put back
in neutral when the right angle was attained, the depressed elevators
would continue to turn the forward part of the craft more steeply
downward.

"Not too steep, Larry. Back with the stick."

Just at the instant that Larry was about to obey Jeff's instruction a
gust of air, coming up warm, tilted the lifted wing more, and as he
corrected for that, trying to get the wing up and the nose higher for a
flatter spiral, his movement was a little too sharp, and the sensitive
controls, working perfectly, but too sharply handled, sent the craft
into an opposite bank, rolling it like a ship in the trough of a
sidewise wave.

Also, Larry meant to try to draw the stick backward at the same time,
coordinating both corrections; but Jeff, a little less calm than usual
because of the superstitious fears that kept riding him, neglected to
speak the words by which he would inform Larry that _he_ was "taking
over" until the correction was made.

By that neglect, both drew back on the stick at the identical instant,
and the nose came up much too sharply.

Larry, not aware that Jeff meant to handle the job, almost pulled the
stick away from Jeff in his anxiety to get the nose down again, and
Dick, in the last seat, thought he felt a sort of thud.

"Hands off! I'll take over!" Jeff said tardily.

He drew back on the stick for, with the throttle rather wide--because
Larry had feared a stall as the nose went up and had thrust the throttle
control sharply forward--the craft began to go down in a very steep
glide, not quite a dive, but with engine on full gun, sending it in a
sharp angle toward earth.

Naturally, when he pulled back on the stick and it did not yield, Jeff
shouted through the speaking tube, "Let go!" for he thought Larry had
lost his head and was fighting his control.

Larry was not doing anything. He had removed his hand from the stick,
his feet merely touched the rudder bar.

Jeff called out something.

They did not realize his words, but Sandy saw his expression.

Almost as though he had been able to hear, Sandy knew Jeff's idea.

"The jinx has got us."

Jeff cut the gun swiftly, and came out of the bank pointed toward the
wide, shimmering waters of Oyster Bay.

"What's the matter?" Larry swung his head to call back.

"Stick's jammed!" Jeff grunted through the tube.

"Jammed?"

"Stuck. It won't come back. It's the jinx! Hoodoo! We're heading down
for the bay and I can't get the nose up!"

Dick, from the back place, saw Jeff struggling with the stick.

If he did not hear, at least his flying study informed him that
something had gone amiss.

Equally, his quick mind arrived at a good guess at the trouble.

The only reason Jeff would swing toward the water and give up working
with the stick must be that the stick would not operate the elevators.

And that, to Dick, spelled disaster.

Its speed accelerated at the start by the engine the airplane picked up
speed rapidly because its nose was steadily going down.

Jeff tugged madly again.

The stick, part of an installed auxiliary control for instruction work,
snapped out of its bed.

Jeff flung it disgustedly out to the side.

Larry sat quietly, knowing well that in no time they would be diving
toward a wet, deep bay--and the end!

Sandy, not fully aware of the situation, but tense, thought of his
'chute, in the seat-pack. Would there be time? Could he use it? He
waited, watching Jeff and Larry.

None of the three noticed Dick.

Seconds counted, he knew.

If the stick was jammed, it might be possible to get into the fuselage.
There he might operate the elevator cable by hand enough to get that
nose up more, flatten the glide, maybe enough to enable Larry, who alone
had a stick, to swing around and come down on land--somehow.

A crack-up would not be as bad, perhaps, as a plunge, a dive into the
bay!

Before his mind flashed the recollection that in construction plans he
had seen provision for getting into the after part of the fuselage.

Not wasting a second, he was already free from his safety belt, climbing
with agile quickness for all his plumpness, onto the fuselage.

It was a fearful risk.

Their speed sent them through the air so fast that the wind was a gale
there on the unprotected top fabric of the fuselage.

With his cotton-stuffed ears tortured by the pressure, with the fierce
wind tearing at him, Dick clutched the seat top as he tore away the
fabric flap covering a sort of manhole back of his place.

Headfirst he plunged in, scrambling, instantly beginning to seek the
points where the control cables passed through channeled guides at each
side.

He was in a dark, stuffy, closely confined and narrow space, his legs
hanging out in the roaring gale, unable to see, half suffocated by the
fumes collected in that restricted area.

He found a cable with exploring hands.

He tugged at it.

It was slack. That told his feverishly acute intelligence that it was
the cable whose lever did not operate. He had seen that Jeff, when he
flung the stick forward to try to free it, had been able to pull it back
again without operating the elevators.

Almost as his hand touched the cable and twitched at it, his other hand,
as he lay with his weight on his chin, face and chest, contacted
something else--a large, roundish object, feeling like a spare landing
wheel tire.

He knew as though the light photographed the truth to his eyes, that
this tire-like object had moved, shifted, fallen onto the cable, wedging
it.

Instantly Dick pushed it into the center of the small space.

Gripping the cable, he twitched it sharply once--twice--three times!

In the dark, he did not know how close the water was. He could not tell
if his alertness had been able to give back the use of the elevators in
time.

Larry, his hand idly on the useless stick, felt it twitch three times.

Automatically he tested it. It came back, and the nose began to come up
a trifle. He did not dare over-control. He had learned that lesson!

The water was rushing up at them--but the stick--might----

Seconds to go!

He must not drag the ship out of that dive too swiftly--a wing might be
torn off.

But with his nerves taut, by sheer power of his cool will forcing
himself to work steadily but not sharply, he brought the nose up,
closing his eyes to that wild nightmare of water seeming to be leaping
toward the airplane.

Jeff shut his eyes. Then he opened them again. No use to try a jump, no
use to do anything but be ready if----

Sandy braced himself.

The airplane was flattening out!

Larry was operating the stick!

The nose came up steadily--with a fraction of time to the good, they
began to come out of the glide to level flight.

Larry braced himself against the slap of the wheels into the surface
water. That might offer just enough resistance to nose them in.

He must be ready to open the throttle and pull up the nose--but he must
not do it too soon, or do it at all in his strained, excited state--he
might go too far.

Level! The airplane skimmed, it seemed to Larry, inches above the
slightly ruffled water.

Gently he drew back the stick, opening the throttle carefully.

"Golly-to-gosh!" he muttered, "that was close----"

When he had lifted the craft and headed for home, he glanced back.

Two legs waved over the last cockpit place.

And in that ridiculous position Dick, a hero upside down, came to earth
at the end of Sandy's birthday flight--on the thirteenth, a Friday, as
Jeff, white and shaken, hastened to remind them.

"But you sure done some swell control job," he told Dick.

"Thanks," Dick retorted, without smiling.

He turned to Larry.

"You did the trick, Larry," he declared. "I only loosened the
cables--freed them----"

"What made them jam, I wonder?" mused Sandy.

"The jinx!"

Dick turned on Jeff.

"Yes," he said very quietly for him. "The jinx! The hoodoo. I think it's
broken, though--in fact, I know it is."

"Why?"

"Because." Dick began to chuckle, "I've thought of a sure way to break
it."

"How?" Jeff was regaining his color and his curiosity.

But Dick grinned and shook his head.

He knew the answer to the puzzle of the missing emeralds!




                               CHAPTER XV
                            A TRAP IS BAITED


"Glad to hear you think the hoodoo is busted," Jeff commented. "Me, I
don't care. I've taken my last hop in that-there crate. I'm shaking like
a leaf, even now."

"Why don't you go to your room and have a lie down?" suggested Dick.

Jeff decided that Dick had the right idea.

Dick watched him go along the gravel path, watched him climb to the side
veranda of the big house, pausing for a moment to tell the newly
installed housemaid about his recent adventure.

"I think I'll go get some lunch," observed Larry.

"Wait!" urged Dick, but said no more.

Mr. Everdail's cousin, Miss Serena, evidently hearing the voices, came
out on the veranda and listened.

"She's coming out to 'make over us,' as she calls it." Sandy saw the
elderly, stern-faced, but kindly lady descend the steps and come rapidly
toward them.

"My! My!" she called, coming closer. "What is this I hear from Jeff?"

"We had a little trouble," Dick said. "Somehow the cable for the
'flippers' got jammed, but Larry got us out of the trouble like a born
flyer."

"Yes," laughed Larry. "After Dick guessed what to do so I could work the
stick."

"Oh, I only crawled back to loosen the cable." Dick tried to make his
exploit seem unimportant. "First time I ever flew around standing on my
head," he broke into his infectious gurgle of laughter. "Sandy, did I
look like a frog stuck in the mud?"

"Whatever you looked like," Sandy retorted, "you did a mighty big thing,
crawling out onto that open covering in the wind, risking being snatched
off or slipping, or having the airplane shake loose your grip!"

"I agree with Sandy," Miss Serena declared. "It was a very fine
thing----"

"I think so," agreed Sandy. "He gave me one gift for my birthday at
breakfast. But just now he made me a present of my life."

"He did that for all of us." Larry put an arm affectionately around his
chum's shoulders.

"A very fine thing, Dick." Miss Serena smiled gently. "Now you had
better go and lie down, and I'll have the maid bring up some hot cocoa
and something for you to eat."

"That is just what I need, ma'am," Sandy told her.

"I think we'd better get this crate into the hangar--we'll get the
gardener and the caretaker and push it in," Dick suggested. "I always
get over a scare quicker if I'm busy doing something to take my mind
away from it."

"Very well," the lady agreed. "I shall have a good lunch ready when you
come in."

She started away, but turned back.

"What caused the--the--trouble?"

"Jeff calls it a 'jinx'--a 'hoodoo'," responded Dick.

"Jeff is silly," she said with some annoyance. "There are no such
things."

"I don't know--" Larry took up the argument. "It is not usual for a
cable to jam. It might break, but one shouldn't get caught."

"I see. Don't think for a moment, Lawrence, that it was caused by
anything but Jeff's carelessness, because of his fears."

She went to get their lunch ordered.

"Did I play up to you all right?" Larry asked. "I saw you didn't want to
explain anything." Dick nodded.

"You did just what I wanted," he said. "Let's get the airplane in. Then
we can talk."

With others of the new group of servants they took the craft to its
place.

As soon as they were alone, Dick climbed up onto the back of the
fuselage, dived down into the small space, while Larry waited an agreed
signal, in the after seat, and pulled his chum out.

"Great snakes!" cried Sandy, then lowering his voice. "How did that get
there?"

Dick, emerging from the fuselage working compartment, displayed a large,
fat, round object.

"The life preserver--from the yacht!" gasped Larry.

"How did it get there?" repeated Sandy, stunned.

"Jeff!" said Dick, briefly.

"Oh, no!" declared Larry. "Jeff is a good pilot. He'd never leave
anything that could shift about and cause trouble."

"But how did it get there?" Sandy reiterated. "I thought----"

"We all thought it went back to the yacht," Larry finished his sentence
for him.

"It did," said Dick, seriously. "I know that after Jeff brought it in,
the caretaker in the hydroplane took it out--and I've seen it at the
stern."

"Well, this may not be the same one--we can easily find out."

Larry hurried from the open hangar, followed by his two friends. At a
trot they went through the grove and down the path, after Dick, dropping
the life preserver onto the after seat, jumped down.

As soon as the yacht came in sight, they stared toward the stern.

"That's queer," observed Larry. "I see a life preserver hanging in its
regular place. This must be another one!"

The one in the airplane, Dick argued, was "the one"--and the one on the
yacht was a substitute.

"But why was it put there?" demanded Sandy.

Dick eyed him with surprise.

"Suspicions Sandy--asking that?" he teased.

"I'm trying not to suspect anybody. Instead of doing that I try to
believe everybody's innocent and nothing is wrong. I'm going to let you
do the suspecting."

"That's turning the tables on you, Dick," Larry grinned. Sobering again
he turned back to Sandy.

"I think Dick is working out something we may be able to prove," he
argued. "I think I see his idea. Captain Parks was the only one who
could open the cabin safe. He is a seaman, and he would know that a life
preserver isn't bothered with except if somebody is overboard or in some
other emergency. Supposing that he meant to help some one in America to
'get away with' the emeralds----"

"He would tie them to a life preserver and throw them over where
somebody he 'expected' could get them," agreed Sandy, with surprising
quietness. "Only--a woman threw the life preserver."

Dick nodded. Sandy threw another clog into the nicely developed theory.

"Furthermore, Captain Parks was on the bridge at the time----"

That all fitted in, Dick asserted.

"I am working on the notion that Captain Parks agreed with somebody not
on the yacht--to get the emeralds. But he made up his mind to get them
all for himself!"

"So he hid them in the life preserver." Sandy spoke without enthusiasm,
making the deduction sound bored and commonplace, although it ought to
have been a striking surprise, an exclamatory statement. It would have
been, Larry thought to himself, if Sandy had made it. Was the youngest
chum jealous of Dick, displeased because it was not his own discovery
that led to the hiding place of the jewels--if they were right?

"You thought of the life preserver as a hiding place?" asked Dick.

Sandy nodded.

"Where else?" he argued. "Captain Parks couldn't get a better or safer
place, right in front of everybody and never noticed. If the life
preserver was thrown into the sea--it would be recovered."

"Doesn't it get you excited?"

"No, Dick! Why should it? I thought of it. But I'm not telling all my
ideas, any more. I'm not 'peeved,' but I mean to be able to prove this
before I accuse anybody again."

"We can prove it--come on!"

"No need," declared Sandy. "I noticed while we were on the way to Maine
that a new life preserver was on the stern of the yacht. I saw it hadn't
been cut and sewed up, so the emeralds couldn't be in that--or in any
other one on the yacht. And, when Dick made his discovery, just now, I
examined the one he found for cuts and marks of being sewed up."

"I didn't notice any," admitted Larry.

"Bang! Another theory gone up in smoke!" Dick was rueful.

"All the same," Larry commented, "Jeff didn't put the preserver in his
fuselage, and Captain Parks could open his safe and no one else knew
how, he declared! There are some things I can't work out and I wish I
could."

"Let's make whoever knows anything--er--let's make them work it out for
us," suggested Dick. "Let's bait a trap with the life preserver--leave
it where it is, get Mr. Everdail to call everybody together, and we'll
tell what we found and what we think is in it--and see what we see."

Eagerly Larry consented. Sandy nodded quietly.




                              CHAPTER XVI
                          THE "BAIT" VANISHES


Simple and clever, Dick's plan appealed to Mr. Everdail.

His library, that evening, made Sandy think of a "mass meeting of
creditors or stockholders who have been tricked."

The room sheltered a mixed assembly. Jeff was there, and so was the
seaplane pilot, Tommy Larsen, and his former "passenger" supposed to be
a special agent from London.

Miss Serena, with the yacht stewardess, uneasy but clinging close to the
older woman, made up the representatives of the ladies' side, while
Captain Parks, his chef, mate, engineer and their helpers and crew, with
the caretaker and all the new servants, filled one end of the room.

"Now you know why there was so much excitement as the yacht came in,"
Mr. Everdail completed a long speech in which he told the astonished
gathering about the missing emeralds. "That is, those of you know who
didn't know before," he added meaningly, and went on quickly. "I decided
to tell you because somebody on that yacht was 'in cahoots' with
somebody else, and if any of you know who it is, it will be worth ten
thousand dollars to you to point out the right one and help me prove
you're right!"

"That will start something!" mused Larry as many exclaimed, and others
looked startled at the disclosure of the large reward.

By agreement Mr. Everdail watched the sailors and servants to note the
effect of his story. Sandy, without doing it openly, watched Jeff.
Larry's eyes covertly observed Tommy Larsen and his associate and Dick
noted the action and expression of Captain Parks.

"There's some one who knows something!" Larry decided as he saw the
passenger of the cracked-up seaplane bend forward, intent, but without a
trace of expression. He had the sort of face that can completely conceal
its owner's emotions.

"I've discovered that Captain Parks has a hand in this somehow," Larry
determined, as he saw the mariner's eyes shift. Larry followed the
swift, instantly changed direction of the seaman's glance.

"He looked smack at the stewardess," Larry added to himself.

Sandy's watchfulness drew blank.

"Jeff didn't turn a hair," Sandy murmured under his breath. "He knew all
about it, of course. But--just you wait, Jefferson-boy, till Mr.
Everdail 'springs' the trap."

As soon as the sensation created by the large offer was over, everybody
looked suspiciously at his or her own neighbor.

No one spoke.

The millionaire waited a decent interval for someone to come forward,
and Miss Serena finally broke the spell of silence by saying, quietly:

"You won't find out anything by that, Atley."

"Why not?"

"Because--" She spoke in harmony with her name, pronouncing her words
serenely:

"Because--the person who threw the jewels off the _Tramp_--isn't
here--and wasn't suspected or seen."

"As I live and breathe!" The rich man rose, while Dick, Larry and Sandy
almost bounced out of their chairs.

"Serena, explain that!" he added.

"It was your wife's French maid--Mimi!" she said quietly.

"How do you know?"

"Did you see her?" broke in Sandy, astonished.

"I did not see her," Miss Serena replied to Sandy while she answered the
older man's question in the same breath. "But I saw a glimpse of dress
just afterward." Her expression showed confident assurance.

"Why, Miss Serena!" Jeff was stunned. "I didn't know you was one of
these-here detectives."

"I'm a woman and I use my eyes," she responded quietly. "A woman needs
only to catch a flash of a dress to identify it. Mimi's maid's outfit
has a distinctive cap--and I saw her cap just as she turned into the
after cabin--I was on the bridge. I went there immediately but she had
gone out through the galley door and I could not locate her."

"Why didn't you tell me?" her cousin demanded.

"There was no need. She had taken only the imitations--the ones you
found."

"But she knew them," objected Dick. "She wouldn't throw over the wrong
ones and she couldn't get the right ones."

"She threw over both sets!"

The Sky Patrol gasped in unison. So did all the others.

"But she couldn't get the real ones!" persisted Dick.

"She did not know she was throwing them over!"

There was another chorus of amazed exclamations.

"Explain that," commanded the millionaire sharply.

"She--did--not--know--that the real emeralds--had been--hidden--in the
life preserver she used!"

"Who put the real ones there?" Larry spoke abruptly in the astonished
silence.

He did not need to have her reply. Captain Parks was red and white by
turns.

"I hid them to keep them secure!" he stammered, turning toward his
employer. "I had no wish to take them. I felt--sure--nobody knew the
combination of the cabin safe--but I couldn't say that a clever man,
some 'Jimmy Valentine' fellow, might not get in. So I decided to hide
the real emeralds--and what was safer than a life preserver?"

While eyes were fixed on him, surprised, accusing, unbelieving, he spoke
haltingly to his employer:

"I hope you'll take my word for it, sir."

The millionaire hesitated.

"I believe you!" Larry spoke earnestly, reassuringly. "It's a perfectly
reasonable explanation."

"But how did you get them into the life preserver?" asked Sandy.

"Took off part of the cover, cut the rubber, put them in, wrapped in
oiled silk to make a tight pack, then used some rubber patching cement I
keep for torn rubber coats or boot patching, and with a hot electric
iron I vulcanized the rubber together and put back the covering."

"Then there weren't any stitches to be discovered!" exclaimed Dick.

"None!"

"Then we're all right!" Larry leaped to his feet. "We can restore the
jewels!"

"Certainly we can!" agreed Sandy. "And Mr. Everdail can telegraph his
wife to have Mimi arrested----"

"And she will have to tell who was her partner," added Dick.

"Now you had better go and get that life preserver, and we'll cut it
open," suggested Mr. Everdail. "I guess it's safe enough hidden in the
tail of Jeff's plane--" He was baiting their trap. "Don't look so
surprised, Jeff--that was what caused your 'hoodooed' crate to go out of
control--but we don't suspect _you_ of putting it there!"

Sandy, Dick and Larry had left the room by the time he completed his
sentence.

Reaching the hangar, with Mr. Everdail's private key they opened the
smaller door, and used a flashlight to locate, reach and climb to the
tail of the airplane's fuselage.

"Now--out comes--why!----"

Dick and Sandy saw Larry's dazed face.

Instantly they knew the worst!




                              CHAPTER XVII
                         A FIGHT FOR A FORTUNE


Into the waiting assemblage in the Everdail library plunged Sandy with a
white, frightened face and his breath coming in gasps after his run.

"It's--gone! Mr. Everdail--the life--preserver----"

"Gone? That can't be!"

"It is, sir!"

"I don't see how--" Mr. Everdail was thinking, as was Sandy, that with
everyone whom they suspected, except the maid Miss Serena had accused,
present in that room, the loss of the carefully hidden object must be
impossible.

"When did you last see it, wherever you had it?" asked the man from
London, cool and practical.

"Just before--the meeting here, sir!"

"It was--where?"

"We left it where Dick had discovered it--in the fuselage of Jeff's
airplane. One of us watched, taking turns, all afternoon. Just before we
came in here we made sure it was all right, and Larry, who has the
longest reach, pushed it in as far as he could get it and still be able
to take it out again."

"Could that girl, Mimi, have come back?" Jeff wondered.

"Whether she did or not," the pilot, Tommy Larsen, jumped up, "if the
life preserver was safe an hour ago, and gone now, it was taken during
that hour. Maybe within the last few----"

"Yes--I think it was in the last few minutes!" Sandy declared. "We
didn't talk about the emeralds being hidden in it until almost the last
thing before we went to fetch it here."

"Let's search the estate!" urged the pilot.

"Come on, everybody--spread out--" cried Jeff. "We'll get that-there
girl----"

"Wait!" begged Sandy. "Everybody will get mixed up and hunt in the same
places. We ought to organize----"

"Sound common sense," commented Miss Serena. "But if you ask----"

Sandy guessed that she would have given her opinion, if asked, that the
search was useless.

She was given no time for the comment. Leaving her with the white-faced
stewardess and the pilot, whose injuries prevented him from being of
much use due to his evident weakness, the others, under Mr. Everdail,
were grouped into parties. Given a definite territory, each set out, one
group to search the grove under Jeff's leadership, another to cover the
shore section, boathouse and boats, with Captain Parks and his men in
the party. Others, under the mate and engineer, divided the rest of the
searchers to beat the further and less cultivated woods on the estate
and to walk the roads, while Miss Serena gladly agreed to telephone to
outlying estates, and to the nearby town to have a watch kept for any
unknown person, woman or man.

"Where's Larry--and Dick?" asked Jeff, as Sandy ran beside him.

"Searching the hangar----"

"But it was locked and all doors down," Jeff grunted. "Why waste time
there?"

"I guess we thought, just at first, somebody might have hidden the
preserver somewhere--we thought we saw somebody in the hangar the day
the mystery started, but we found no one, so Dick thought----"

"Well, go tell them to come and help me in the grove. Don't waste time
there!"

Sandy separated from the superstitious one, as the latter rushed among
the trees, muttering that some omen had warned him of trouble.

As the beaters separated, and widened the circle of their search, the
sounds of calls, shouts, voices identifying one another grew fainter.

Sandy, reaching his comrades, compared notes.

"They've organized and started," Sandy reported. "What have you two
found?"

"Nothing," Dick said dejectedly. "We ought not to have left that thing
unguarded."

"Not with a fortune in it," agreed Larry. "But we were so sure----"

"Whoever got it can't be far off," interrupted Dick. "No one but Miss
Serena and Captain Parks--and we three--knew about the hiding place
until the last part of the meeting."

"Let's lock up, here, and join Jeff," suggested Sandy.

"Where is he?"

"In the grove, Dick."

"All right," Larry moved to the small door. "The spring lock's set. The
place is surrounded. Nobody's in here--" They were outside as he made
the last statement. "Slam the door and try it, Dick. All right. Come on,
let's find Jeff."

The search took longer than they expected.

To all calls the thick grove gave back only echoes.

Dick, rounding a tree, stumbled.

"Larry--Sandy--come--quick!" He called his chums in a strained voice.

When they reached him, in the dying glow of the flashlight Dick trained
on a body lying in a heap, they identified the man who had been warned
by his gypsy fortune teller to "look out for a hidden enemy." He was
lying at full length in the mould and leaves.

"Jeff!" Dick knelt and lifted the man's head.

"Huh!--uh--oh!"

Slowly, while they held their breath, understanding came into the dazed
eyes, the breath was drawn in, and Jeff struggled to a half-reclining
posture.

"What happened to you?" begged Sandy.

"The rest--oh, I'm sick!--I got a bang in the solar plexus--I sent the
rest of the men out to the edge of--the woods--oh!--my stomach--to beat
in towards me--when I come around this-here tree, somebody was waiting
and poked me--oh!"--

"Then somebody is still close. How long ago?----"

"I don't--know--I passed out----"

"Hey--everybody--yoo-hoo!" Larry cupped his hands and began to shout in
various directions.

The crash and call of the beaters coming in began to grow louder.

Unexpectedly, from the water of the inlet, and yet in a muffled,
unnatural tone, there came the sputtering roar of a motor.

"What's that?" cried Dick.

"One of the airplanes--somebody's in the hangar----"

"No, Sandy, it's from the water."

"But there's no boat out--the only boat with an engine is the
hydroplane----"

"The yacht tender's tied to the wharf," Dick reminded Larry.

They raced down the sloping woods path.

"Where's the guard--where's everybody?" Sandy shouted.

The men came running. They had scanned the place by the wharf, and,
satisfied that no one lurked there and that the tender was secure, they
had gone further along the inlet coast.

"No one's in the tender!" Larry exclaimed.

"It's the hydroplane, then!" Dick decided. "It's coming from the
water-dock inside the boathouse, now--there it is. Hey! You! Stop!"

Seamen, the mate, Pilot Tommy Larsen, servants, dashed up.

"What's happened? What's the excitement? The hydroplane--there it goes!"

Their shouts came in a chorus of helpless questions and suggestions.

"Man the yacht tender!" ordered Captain Parks. His men tumbled into it.

"That isn't fast enough!" objected Pilot Larsen. "I'd fly that amphibian
crate only--I'm too weak and dizzy----"

"Jeff's hurt, too," said Dick, desperately. "I guess they'll get away
with the emeralds!"

"Why can't Larry fly the 'phib'?" demanded Sandy.

"At night? I haven't had any experience."

"But Jeff could go along." Dick took up the idea eagerly. "Couldn't you,
Jeff? And tell him what to do in an emergency!"

"Yes--sure I could! Not in the 'phib' because we don't know how much
gas--the gauge is out of whack--but we got the airplane ready this
morning--if it wasn't the night of the thirteenth I'd have said
something about it long ago!"

"Forget about the thirteenth--remember the thirty emeralds!" cried
Sandy. "Come on, all--help us get that crate out and started. It's a
flight for a fortune!" They took up the cry. Dick and Larry ran off.

Those of the servants and seamen who were not too excited by the escape
of the hydroplane to hear, followed the Sky Patrol as they raced through
the grove. Jeff, supported by Sandy and friends among the men, came more
slowly, still unwell from the blow in a tender spot.

"Mr. Everdail could fly the crate if he was here--he's an old war
pilot," said Larsen, but they did not wait to locate him. As soon as the
engine was warmed, the instruments checked, in spite of the delay at
cost of precious moments, Larry donned the Gossport helmet, Jeff got in
behind him, Sandy and Dick, without waiting for invitations, snapped
their belts--the engine roared--and they were off!

Larry was keyed up to a high tension; but he had no lack of confidence
in himself. Night flying, of course, differed from daytime piloting. But
Jeff was in the second seat, with the Gossport tube to his lips.

Sandy and Dick were in their places, ready to observe and to transmit
signals by using the flashlamp--one flash, directed onto the dash before
Jeff so it would not distract Larry, meant turn to the right, two meant
a left turn, three quick flicks would tell of the discovery of the
hydroplane.

Jeff was too upset to pilot; and since the morning adventure he had no
second control stick; but he could give instructions.

"I see a light," Sandy said as the airplane swung far out over the dark
water. "A green light, but the hydroplane wouldn't carry lights."

As they swung in a banked turn to circle over the Sound, the green
disappeared and its place was taken, as it seemed, by red.

"Dick!" Sandy turned and gestured, pointing.

"I see it!" Dick located the tiny light well below them.

"The hydroplane must have its electric running light switched on," Sandy
mused, unable to convey his idea, because Larry had the engine going
full on.

"That must be the hydroplane," Dick decided. "He--whoever is in it--is
afraid to run without his lights."

Three swift flicks of his own flash showed to Jeff.

"Larry, they've spotted that-there boat," Jeff spoke through the tube to
the young pilot. "Yep. More to the left. That's it--both at the same
time! Stick to the left, rudder, too. Good boy. Now the stick comes back
to neutral. Hold her as she is--better cut down the throttle a little as
we bank and turn to the left."

Thus began their flight for a fortune!




                             CHAPTER XVIII
                               OUTWITTED!


From their cockpits Sandy and Dick watched the hydroplane. At cruising
speed their airplane made nearly three miles to the hydroplane's one.
Its mysterious occupant must know that they were trailing him, but he
held to a straight course so that his lights were never in a different
place as their craft above swung to show its observers the red and then
the green.

"He's making straight for Greenwich, on the Connecticut side," Dick
decided, knowing a good deal about the Sound ports.

"How are you fixed?" Jeff spoke to their youthful pilot through his
tube.

Briefly Larry swung his head, nodding.

"We'll be getting tired of turning to the left all the time," Jeff
suggested. "Think you could follow a sort of zig-zag, flying slantwise
across the course of that-there boat, then coming around an angle and
flying slantways back to the other side?"

Larry nodded emphatically.

"Good! Here we go--to the right. Get your eye on that Fall River Liner,
coming up the Sound--that's about the point of our first leg.

"Now, touch of right rudder and right aileron--and stick back to
neutral. There! She's level. Keep moving stick and rudder a bit,
steadily. Now she's banked and turning. Neutralize! That's the ticket.

"There! The nose is on that steamer. That's it--don't let her swing off
that point for awhile--and watch that you don't nose down--that's right,
back a bit on that-there stick, up she comes, stick back to neutral."

Thus directed, and admonished, Larry managed to give the airplane a
swinging, zig-zag course, so that its greater speed was used up in the
longer legs of its slanted progress, and since the hydroplane did not
try any tricks or change its path, the Sound was being crossed in the
wake of the steamer by the boat and in a corkscrew path by its aerial
bloodhound.

"I think I know what is going to happen," Sandy decided, as they crossed
the course of the hydroplane so that its two tiny colored beams showed
at the same instant. "He'll wait till we get closer in to the
Connecticut shore line and then he'll 'douse the glim' and leave us with
nothing to watch."

Bending forward Dick began to rummage in a compartment built in his
section of the seating space.

He believed that he could outwit any effort to escape by taking
advantage of the landing flares, attached to small parachutes, which
Jeff carried as a precaution during his former night hops to the old
estate.

"Better cut the gun and glide down a couple of hundred feet," Larry
heard Jeff's voice in his earphones. "If he tries any tricks----"

"That's queer!" Sandy exclaimed to himself, as he stared down and saw
the small, swift boat open a vivid, glowing eye at the bow.

The helmsman had switched on its searchlight.

"What's that for?" Dick wondered.

Jeff, warned by the trail of light on the water below, took a quick
look.

"He must be looking for his landing!" Sandy called.

Larry, holding the airplane in a moderate glide, saw the beam glowing
out beyond the airplane's nose, felt that he was as low as he dared be
with land ahead, and drew back on the stick to bring up the craft to a
level keel, opening the throttle as the glide became a flat course about
three hundred feet higher than the water.

"He's swinging the boat out to open water again!" cried Sandy.

"There it goes around!" shouted Dick, unheard, excited, as the beam of
the hydroplane swung in a wide arc from shore, heading once more back
toward Long Island.

"He's going back!" Sandy exulted. "We'll get him!"

"Good boy," Jeff spoke to Larry. "You made that turn without a hitch.
With that searchlight to guide you, I don't need to talk through
this-here thing any more."

Larry had no trouble following the boat with the white beam as a guide.

It puzzled Sandy, and he swung around to look questioningly back at
Dick. The latter, unable to see his expression, but guessing his idea,
shook his head.

"It's time to find out what's what!" he muttered.

As Larry banked and came around on a new slant across the hydroplane's
path, which seemed not so true to the straight line as it had been, Dick
secured a parachute-equipped landing flare, sent it over safely past the
wings, and watched the white glare light up the surface of the water.

To Larry's disappointment, they were so far to one side and behind the
hydroplane that the flare failed to disclose its occupant.

He held up a hand, and pointed ahead, then opened the throttle, came
onto a straightaway course over the hydroplane, rapidly overhauled it
and got well ahead. Then, cutting the gun and gliding, as it came up
under them, he signaled, and Dick, waiting, ignited a second flare.

All four of the Sky Patrol members gasped as the light blazed out.

Larry looked back at his companions, amazedly.

"It's--empty--nobody in it!" he cried.




                              CHAPTER XIX
                          A BAFFLING DISCOVERY


"Somebody had to be in that hydroplane," Sandy mused. "They were there
to switch on the light, to turn the boat, and to set it on the new
course!"

Quickly he peered to the side and back, downward at the water in the
place where the first landing flare had settled into the water.

Just a little closer to their position, should have been the spot where
the clever miscreant might have abandoned the boat.

Sooner than that, Sandy guessed, the unknown person could not have quit
the hydroplane: otherwise the turning from shore would have continued
and the hydroplane, instead of proceeding in a straight course away from
land, would have swept in a wide circle, round and round.

"There's no life preserver in the boat either--so that's what the
mystery man used to swim away with--Mr. Everdail's jewels!" he added.

Straining his eyes, he peered, looking for a bobbing head, a round white
object supporting a body, as the flare died. Dick, arguing in much the
same fashion, stared from the other side of the fuselage and gave a
shout of elation.

"There!"

His arm pointed.

Sandy prodded Jeff, and quickly the pilot, much recovered, gave Larry
his instructions.

"Nose up--we're getting too low. Right! Now a right bank--not too steep.
Don't get excited. That-there lad in the hydroplane headed her outbound
and then took to the water. Now we're heading in--steady with that-there
rudder--don't try to jam her around--now she's all right. Level off and
hold her as she is."

Larry obeyed all instructions, doing the work as Jeff gave the order.
Larry was rapidly growing sure of his ability.

He fought down the excitement that wanted to express itself in hasty
manipulation of his controls and kept a steady hand and a cool brain.

Dick, scribbling hurriedly, passed a note to Sandy, who read it in the
light of the flash, and then passed both paper and light to Jeff.

Dick, recalling a wide, spacious cement-floored parking space at a
nearby bathing resort, had suggested "setting down" there. As he read
the note Jeff shook his head.

"Dangerous trying to land there!" was the note Jeff passed back as Larry
flew the airplane at just above stalling speed toward the shore. Dick
agreed. After all, there might be automobiles in the parking lines, and
the light might be bad for Larry. Even using a power-stall by which,
with the engine going and a flat gliding angle, the airplane could
settle gradually closer until it took the ground with hardly a jar, the
maneuver would not be safe, Dick admitted.

"Here comes another 'plane!" Sandy called out, taking the flashlamp from
Jeff again as the older pilot handed it back. "He's flying right after
us."

They all located the drone of the other engine.

"Steady, Larry!" Jeff cautioned. "Hold as you are. That-there is our
amphibian--and I reckon the boss is doing the control job."

The amphibian, as they made out its pontoon understructure, came fairly
close alongside. Its speed was almost identical with their own and at
first all four occupants of the land crate wondered who was in it, and
why.

"Signaling!" cried Larry, cutting the gun and turning to observe.

"All right, buddy," admonished Jeff. "Stick to your job. Sandy or Dick
will read the dots and dashes--if he's using Morse code----"

"He is spelling out something with his flashlight," Sandy decided, as he
saw short flickers and longer dashes of light while the amphibian kept a
course within close range but at safe wing distance.

"I've got it!" Dick passed forward his paper.

"'G-i-v-e r-e-p-o-r-t,'" Sandy read, and as he handed Jeff the note,
Sandy, using his own light, sent back the Morse code answer:

"Man swimming ashore with life belt."

Then, with the beam directed in the path the mysterious unknown must
have taken, he tried to show the occupant of the amphibian what he
meant.

Evidently the endeavor succeeded, for the amphibian dived, and took to
the water, while Larry, directed by Jeff, swept around in a circle out
of range if the amphibian rose unexpectedly, but within visual range of
its maneuvers.

Watching intently, his comrades saw that the amphibian kept on toward
shore in a taxiing course on the water surface.

A shout greeted the advent of an automobile on a shore drive. As it
swung around a curve, close to the water, its bright headlights fell in
a sweeping line across the water--and picked out a round, white dot
bobbing, vividly lit, in the rays.

The amphibian was headed directly for it.

It went close, just as the swinging lights swerved and were gone.

"Drop another flare!" shouted Larry.

Sandy caught and relayed the suggestion as they retained their swinging
curve.

With the glare from the dropped light picking out things in sharp
silhouette, they saw a man clamber out onto a pontoon and rescue the
floating prize.

"Now, I wonder if that is Mr. Everdail--or if it's somebody else?"
thought Larry, correcting for a tendency of the nose to fall away.

"Whoever it is," he concluded, "he can't get away. He has the life
preserver. But we have superior speed. And a good tankful of fuel."

He glanced at the gauge to reassure himself, made an almost automatic
correction of a wing tip, pushing up in a gust of air as he saw that his
surmise about fuel was correct.

There was no need for the concern that all four felt for the moment.

As soon as it got under way again and took up its climb, the amphibian,
coming to their level, showed its pilot holding up the life preserver,
as the flare still settled toward the water. In the glow they recognized
the triumphant, smiling millionaire.

The flight back to the landing field was without event. Larry made the
landing first, and his companions tumbled out to join the waiting
cluster of people while they all "took hold" to run the airplane out of
the way so that the spiraling amphibian, its wheels down, could shoot
the flare-lit field, and land.

"Here!" Mr. Everdail was triumphant as he threw the life preserver out
of his cockpit to Larry. "As I live and breathe, that life preserver
ought to be in a museum!" He grinned as he came to the ground. "That's
the flyingest life preserver I ever saw--first it goes joy-riding in a
seaplane, then in the 'phib' and now it runs off on the Sound and comes
riding back with me."

"Let's see what's in that-there!" Jeff urged. "That's most important,
right now!"

The crowd trooped into the hangar, where Larry, at Jeff's direction,
switched on the overhead electric lamps.

Close around Mr. Everdail, Jeff, Captain Parks and Miss Serena, with the
youthful Sky Patrol in their midst, the rest of the sailors, and most of
the house servants gathered.

"Somebody give me a good knife," ordered Mr. Everdail. "We'll cut this
thing to ribbons and get rid of all the suspense!"

Larry held out the round, heavy inflated "doughnut" as half a dozen
pocket knives were unclasped and held out to the millionaire.

Taking the long-bladed one Sandy produced, Mr. Everdail advanced.

"Hold on, sir!" Captain Parks stepped forward.

"What's the matter, Parks?"

"Son, turn that preserver over--let me see the other side."

Surprised, Larry did as he asked.

They all saw the captain's face assume an expression of disgust.

"That's not the life preserver from the _Tramp_," he grunted.

"What?"

"You know as well as I do, sir," the yacht captain turned to his
employer to answer his amazed cry, "you know that all the life
preservers have the yacht's name and port painted on them."

"And that's so, too," said the mate, advancing and backing up his
captain's declaration.

"No, sirree!" Captain Parks stated. "That's not the yacht property. It
hasn't any marks on it at all."

"Maybe it's the one off the hydroplane," Larry was dejected, but not
convinced that the life preserver was a strange one to all.

"Not that!" the mate declared. "It'ud be marked _Scorpion_. No, Mr.
Everdail, this is no life preserver we've ever seen before."

"Well, anyhow, I'm going to cut into it."

"Please, sir, do that!" urged Sandy. "I can be sure it's the one we
found in the airplane fuselage, anyhow--I remember that little rusty
stain in the cover."

"Cut," said Jeff, "but something tells me you'll waste time."

Sandy, Larry and Dick shook their heads, looking hopeful.

But Jeff was right!




                               CHAPTER XX
                      SANDY TURNS OVER A NEW LEAF


From the rear of the crowd in the hangar, Pilot Larsen came forward.

"Who was in that boat?" he asked. "Could you recognize him?"

"The flares died just too soon," Dick informed him. "Maybe Mr. Everdail
saw more than we did."

The millionaire shook his head.

"There's one way to check up," Jeff suggested. "Who's not here who was
in the house before the life preserver was missed?"

"You can learn nothing from that," Miss Serena spoke up. "Too many are
away."

"We can get somewhere, anyhow," Larry insisted. "Captain Parks, can you
account for your men?"

"Yes, sir. Those who are not here are in the tender."

"I saw them start to get back Mr. Everdail's hydroplane," Sandy nodded.

"The fellow who flew with you in the seaplane isn't here," remarked
Larry, quietly, and, after a glance around, he said: "Neither is the
yacht stewardess."

"I sent her to her cabin," Miss Serena stated. "She was greatly
disturbed about this affair."

"Oh!" said Larry, slowly, "she was?"

"Yes, but she is a high-strung girl," argued the lady; and during the
silence that followed, she turned to her relative.

"Atley," she told the millionaire, "we are getting nowhere. For my part
I believe that the emeralds have already been destroyed!"

"Destroyed!"

"Certainly. That seemed to be the purpose, in the London hotel. A person
as clever as that must have planned this entire affair and has
undoubtedly accomplished his wish and vanished long ago--or else he can
never be caught because we have no way to discover him."

"He ought to be caught and punished," Jeff argued. "That-there set of
emeralds was too precious for us to let somebody do a thing like
this-here."

"We know who was on the yacht," Larry agreed with Jeff. "At least we can
try to find out who threw the emeralds off."

"We know," Dick broke in. "Don't you remember that Miss Serena
recognized the maid--Mimi--by her uniform?"

"Then why don't we go and question her?" Larry suggested. "Make her tell
what she knows!" A murmur of assent broke out among the seamen who were
naturally anxious to be cleared of any possible suspicion.

"Did you get an answer from Mrs. Everdail when you telegraphed her about
Mimi?" asked Dick.

Mr. Everdail shook his head.

"Not yet," he admitted. "I don't believe Mimi is the one. She was with
my wife during the last seven years and you get to know a person's
character in that time."

"Just the same," Larry insisted, "many respected bank tellers have been
discovered for what they were after bank money disappeared."

"As I live and breathe!" Mr. Everdail spoke gruffly, "I begin to wonder
if you shouldn't be the one to have 'suspicious' for a nickname. You
have suspected Jeff, and me, and my friend who was with me, and Larsen,
here, and his passenger--Captain Parks and now Mimi! It will be Miss
Serena next!"

"My gracious!" that lady exclaimed, "I hope not!"

"I never will," Dick declared.

"I guess I caught the disease from Sandy," Larry was red-faced, "I admit
I deserve the nickname now."

"If Sandy doesn't object to losing the nickname, then--" Mr. Everdail
smiled a little teasingly.

"Oh, he's welcome to it," Sandy cried. "I've turned over a new leaf!"

"How's that?" Jeff wanted to know.

"I used to take one little thing for a start, and make up my mind that
whoever did it was the one I must suspect," Sandy explained. "But that's
like trying to prove a man guilty because _I_ think he may be."

"That's so," Dick began to chuckle. "Pinning clues onto folks is like
the clothing salesman who tried to sell a white linen suit to a man who
wanted a dark grey one. 'I'll give you what you want,' the salesman
said--and he went over and pulled down all the shades!"

"And that-there suit looked dark!" chuckled Jeff.

"Now I mean to listen, and watch, and not suspect anybody, as if I had a
dark suit and a light one to sell and I'd wait to see who the different
suits fitted!"

Breaking into a hearty laugh, Jeff slapped Sandy on the shoulder.

"That-there's the ticket," he said.

"By the way," Captain Parks turned to his employer. "How about that
cruise around New York to see the buildings lighted up that you told me
to get the yacht ready for?"

"As I live and breathe!" Mr. Everdail slapped his thigh. "I forgot all
about our birthday dinner and cruise for Sandy."

"Well, the dinner was being got ready when you sent for us," remarked
the captain.

"A birthday dinner for me?"

"Meant for a surprise?" chimed in Dick.

"I'm starving," laughed Larry.

"Then let's go on board the _Tramp_ and see what the chef trots out."
Mr. Everdail led the way, inviting the others who had not originally
been planned for.

"Thanks," Larsen stated, "I'm too tired. Me for bed."

"That's right," laughed Dick. "After a crack-up, always take a rest-up."

"Now we'll shelve this mystery." Mr. Everdail led the way to the tender
which would transfer them to the yacht for the evening run around
illuminated Manhattan. "Eat, and have a good time, Sky Patrol."

"We will, gladly, sir," agreed Larry.

With the zest of healthy youth the chums "shelved" the mystery and hid
their chagrin at being wrong again. The repast provided by the yacht
chef was worth their attention. Especially palatable was the iced
lemonade which the hot, humid night made very delightful.

"How do they get these ice-cubes the same tint as the lemonade?" Larry
wondered, admiring the yellowish tone of the cubes, as he stirred the
clinking mixture in his tall glass.

Dick grinned.

"Dye!" he chuckled. "If you want special food or drink you have to
dye-it!"

"To diet!" Jeff caught the pun. "That-there's a hot one!"

"It leaves me 'cold'," Larry came back at him. "But I'm interested about
this ice."

"Why?" asked Mr. Everdail, curiously.

"It's simple enough," the youngest member of the Sky Patrol broke in.
"They pour some of the lemonade into the compartments in the ice-trays
and freeze that. It is better than plain ice because it doesn't weaken
the lemonade at all."

"That's right," Larry agreed. "Why, Mr. Everdail, I was only curious. I
don't know much about refrigerating plants and I didn't think they could
turn the ice any color they liked--but I see they can."

He dropped the subject, finished his drink and, with the others, partook
of a frozen sherbet also prepared in the yacht's icing plant.

Finished, they were invited on deck to see the sights of Manhattan's
night sky, with its millions of electric bulbs, on signs and in high
windows, and on skyscraper domes, painting a fairy picture against a
dark heaven.

"What made you speak about the tinted ice?" Sandy asked, softly.

"Only what I explained," Larry retorted. "I hadn't thought about colored
ice cubes, ever----"

"And aren't you taking any hint from the yellow tones?" Sandy demanded.

"No! Why should I?"

"Don't you, Dick?"

"Not a thing, Sandy. What's in your mind?"

"Well--think! If they can freeze lemonade, and get yellow ice cubes,
they can freeze lime juice--even something darker--and get----"

"Green cubes!" Larry broke in. "Yes--or freeze indigo and get blue ones.
What of it?"

"What would dark green ice cubes conceal?"

Both chums stared at Sandy.

What would dark green ice cubes conceal?----

Suddenly Dick gripped his arm.

"Emeralds!" he almost shouted it, but dropped his voice instead.

"What better place could Captain Parks--or anyone else--find if he
thought the life preserver idea might be too open?"

"But the chef would discover it--they couldn't be left there!"

"Certainly they could." Sandy was earnest. "If the Captain ordered that
they be kept for his special use--and if he drank lime juice. Come on,
let's ask him." They followed Sandy to the bridge.

"Captain," Sandy asked, "what's your favorite drink? Lemonade or----"

"I'm very fond of lime drinks----"

Sandy, elated and panting, turned to Mr. Everdail as Dick and Larry
raced away.

"Come on, sir," Sandy panted. "I'll show you your emeralds!"




                              CHAPTER XXI
                        THE SKY PATROL GIVES UP


At Sandy's sensational announcement there was a stampede from the
bridge. Soon after Dick and Larry raced through the cluttered and
deserted dining saloon, it was invaded by the captain, the millionaire,
Miss Serena and others, with Sandy in the lead.

"What did you discover, Dick?"

At Sandy's cry his chum, as well as the oldest Sky Patrol, turned.

"Nothing!" said Dick.

He made a disgusted gesture toward the open front of the refrigerating
box, to the four ice cube trays lying empty on the galley floor.

"They were as empty as our heads!" Larry was dispirited.

"Sure they were!" the chef, who had observed their invasion of his
cookery compartment with amazement, spoke up. "I had to use all of 'em
to freeze the cubes for your dinner. No use to fill 'em again till I
wash 'em up, so I left 'em out while I 'defrost' the box--cut off the
current and let the box get warm enough to melt the frost that collects
when you freeze a lot of cubes."

He indicated the refrigerating unit which had heavy ice clinging
wherever the chill had congealed the moisture from the evaporation of
the water.

"Any other trays?" Mr. Everdail snapped.

"Only them, sir." The chef threw all the compartments wide.

Food, ice-drip trays and vegetables in their dry-air receptacles, were
all they discovered by a painstaking search. A glance into the
"hydrator" packed with vegetables, crisp lettuce, long endive, and other
varieties, a foray behind and under everything satisfied them that
another clue had "gone West"--and left them very much out of favor.

No matter how closely they examined the built-in box, with its glossy
enamel and bright, aluminum trays, nothing except food and drinkables in
bottles revealed themselves.

And that ended it!

"I thought that was how it would turn out," Jeff, coming from the after
deck, declared.

"I'm disgusted with the whole thing," the yacht owner grumbled. "I ought
to have known better than to trust three young men under seventeen to
solve such a mystery."

He reflected for a moment and then spoke his final word.

"I think I shall land you at a Brooklyn wharf, boys, and let you go
home."

"See what Friday, the thirteenth, does for you?" Jeff said.

Neither of the chums had a word to answer.

"The date has nothing to do with it," Mr. Everdail snapped. "It's their
lack of self-control and experience." He turned and stalked out of the
galley and after him, sorry for the three members of the disbanded Sky
Patrol, Jeff moved.

"Sorry, buddies," he said, shaking hands at the pier to which the yacht
tied up briefly. "Don't let it stand between your coming out to
that-there new airport once in awhile to see me. I guess if Atley is
through with you he'll be done with my crate too, so maybe we'll meet up
one of these days soon. If we do, and I have the money for gas and oil,
Larry, you get some more flying instruction. You may not be a
crackerjack detective, but when it comes to handling that-there crate,
you rate mighty good."

He said a pleasant word to each of the other two, added a friendly clap
on the arm and, with Mr. Everdail saying a brief, if not very angry
farewell, the Sky Patrol quit its service, finished its air work and
took to its feet.

Explanations at home accounted for the termination of their stay, which
had been arranged by telephone at the beginning; and it seemed to them
that the Everdail Emerald mystery was, as Dick dolefully said, "a closed
book without any last pages."

So despondent was Larry at his failure as a sleuth that he did not like
to discuss their adventures with his chums.

His depression was more because his air training was over than from a
real sense of failure. To Larry, one only failed when one failed to do
his best--and that he had not failed in.

As a week went by Dick saw something to laugh about in their wild
theories, their almost fantastic deductions. He found an old
stenographers' note book and jotted down, in ludicrous terms, the many
clues and suspicious incidents they had encountered.

But Sandy was really glum.

To Sandy, the fault for their dismal failure lay at his own door.

"If I hadn't gone off 'half-cocked'," he told his comrades, "maybe we
would have seen something or somebody really worth following up."

He made a vigorous mental resolve never to be caught in such a trap
again.

That very afternoon he passed a news stand and was chained in his tracks
by a small headline in black type at one corner of a paper, in a "box,"
or enclosure of ruled lines that set it off from the other news.

"Take a look at this!" he hailed Larry as the latter sat on Dick's
porch, whittling on the tiny struts of a model airplane.

Both chums read the box he thrust under their eyes.

"_Ghost Again Walks In Haunted Hangar._"

Under that heading the story reminded readers that the Everdail estate
had been haunted several weeks before according to report.

The millionaire, it went on, coming East to meet his wife, returning on
their yacht from Europe, had investigated the uncanny events reported to
him by his caretaker and others.

He had learned nothing, the reporter had gleaned from the caretaker of
the deserted estate.

However, it ended, as soon as Mr. Everdail had sailed on the yacht to
join his wife at their lakeside camp in Maine, uncanny light, odd noises
and other strange things had become evident again, as an excited local
correspondent had notified the paper. Reporters, searching, and
watching, had found nothing so far but the public would be informed as
soon as they discovered the secret.

"What do you think of that?" Larry looked up.

"I don't know what to think," Dick admitted. "No ghost does those
things. A real person has some reason for doing them. Who? And why?"

"The only way we'll find out is by going there, at night, and watching,"
Larry declared.

"Not for me," Sandy said, surprising his chums. "We were 'kicked out'
once. If we were to be caught on the place we'd be trespassers--and if
the clever news reporters are watching and don't find anything, how can
we?"

"I'm going to be too busy earning money to finish my flying lessons to
bother, anyway," Larry decided.

"Still--" Dick began, and then, looking down the street, he became
alert.

"Larry! Sandy! Look who's coming. That's the man who flew in the 'phib'
with Mr. Everdail--the day the yacht came in!"

"It is!" agreed Larry. "He's coming here. I wonder what for!"




                              CHAPTER XXII
                      THE "GROUND CREW" TAKES HOLD


"Hello, boys. Remember me?"

Dick rose to meet the man, tall, quiet, and with a smile of greeting on
his face that belied the creases of worry around his eyes.

"I ought to," Larry also advanced, rather sheepishly. "I tackled you the
day you floated the dory out to the cracked-up seaplane."

"Oh, no hard feelings, my friend," the man shook hands. "You wrenched a
shoulder that was already pretty painful--but you thought you had a
jewel robber to deal with, so let's let bygones sleep."

He shook hands and accepted the lounging chair Dick offered.

"I don't believe I've introduced myself," the man began. "I'm Mr.
Whiteside. Of course you wonder what I am here for."

Naturally they did. Each nodded.

"I've kept pretty well in the background of this case," he told them. "I
am, by profession, an official of Mr. Everdail's eastern enterprises.
But I consider myself something of an amateur detective 'on the side'
and I want you three to help me."

"But Mr. Everdail 'discharged' us." There was no resentment, only
remonstrance, in Larry's quiet remark.

"Oh, I know it. I have seen him, been up in Maine. But he has given me a
free hand, and I think you three can be useful. You see, I want that
hangar watched, now that the reporters have gone away. I can't be there
day and night--I know," he broke off to explain, "that you three have
suspected me of having something to do with the wrong side of the
affair, and naturally enough. I came upon Larry unawares, at the
seaplane. I accepted his offer about surrendering jewels and actually
had a gun in my hand at the time. No wonder I fall in line as--well, as
a suspected person. I don't hold that against you. As it happens, I am
trying to recover the missing jewels, just because I made such a failure
of rescuing them before."

That might, or might not be true, Sandy reflected; but he maintained a
careful guard over expression and speech.

"We aren't doing anything about the mystery," stated Sandy, wondering if
that might be the plan--that this man had come to try to pump news out
of them. If so, Sandy was determined that as long as they had given up,
been given up, it did not matter if the man knew it or not.

"But you will do something! To help me out?"

"What?" Dick asked, with a mental reservation as to any promise.

"Why, go out to the Everdail estate, under my direction, and watch."

"We'd be trespassers," argued Sandy. "We might be arrested."

"I can arrange all that."

Mr. Whiteside turned directly to Larry.

"I need you for something else," he said. "Atley Everdail isn't here to
help, if any situation developed where I would need a pilot. I have a
theory that makes me think I shall need one----"

"What about Tommy Larsen?"

The man who had piloted the cracked-up seaplane was again able to fly,
he responded, but was not safe for a long flight. Besides, the detective
argued, he wanted someone who had proved himself trustworthy in more
things than flying.

"I've had only about nine hours instruction," Larry said honestly. "I
wouldn't like to risk soloing on that. I can taxi, handle the 'plane to
get into the wind, take off and fly level, bank, turn, circle, spiral,
climb, shoot the field and set down. But----"

"That is all settled in advance," Mr. Whiteside stated. "Tommy Larsen is
'kicking around' without a job. I've got his consent to finish your
instruction, and put you in trim for a license by the end of Summer."

Sandy, watching his friend's face take on an eager light, a look of
longing, decided that Mr. Whiteside could not have found a more certain
way to fascinate Larry and enlist his cooperation.

Dick, too, showed an interested face.

"That would be great!" Larry declared. Then he became more serious,
adding. "Finishing up my course would be fine, but if it means that I'd
have to do anything against Mr. Everdail's wishes, after he told us----"

"He wishes to recover those emeralds, my boy."

"But he has agreed with Miss Serena that they are destroyed," Dick
objected.

"And I think they are not destroyed!"

He gave them his theory.

"When Everdail gave me all the facts he had about the London attempt to
ruin the emeralds, the first idea I had was that some independent robber
had failed to find the real gems and, in spite, had damaged the
imitations."

"But no other jewels were taken!"

That supported his decision that neither a single robber nor a band of
miscreants had planned the affair. They would have taken all the real
stones, and he believed that these were numerous.

"I weighed the situation," went on the detective. "A robber would be
enough of a gem expert to know the stones were imitations and would have
taken the others. But--some Hindu fanatic, in India, where the emeralds
came from originally, might have a fixed idea that they must be
destroyed. He might not know imitations from real ones."

"That would explain why acid was put on them," agreed Dick. "It wouldn't
explain any other attempts, though."

"No! I argued that as soon as a Hindu accomplished the entry to the
hotel and believed he had destroyed the stones, he would stop."

"Then why did you and Mr. Everdail fly out to meet the yacht?"

"We wanted to take every precaution, Larry. There was a chance that no
Hindu was involved. It might be someone with what the French call an
_idee fixee_--a fixed notion--a demented purpose of destroying
emeralds--no other stones were treated with acid except those lying in
the little pool around the emeralds."

"Are there people as crazy as that? And going around, loose?"

"Once in awhile you hear of such people, Dick."

"Well, wouldn't anybody in England give up then?" asked Larry.

"Anybody who remained in England would have to--he'd be left there.
But--" Mr. Whiteside leaned forward and spoke meaningly, "--a man sailed
from England--and although I did not know it at the time, I have checked
up, since, and the man from London is an English circus acrobat--who
went in for 'stunting' on airplanes."

"The man who claimed to be a secret agent of a London insurance firm?"
asked Dick, amazed.

"The firm sent no investigator!"

"Then we have found the man who is guilty!" exclaimed Dick. "He was with
Tommy Larsen, hired him to go out to meet the yacht!"

"That seems to be the fact," Mr. Whiteside admitted. "Before the arrival
of the yacht I had no inkling that this fellow had come over; but Mrs.
Everdail was so nervous and worried, we decided to fly out to meet the
yacht, just as Jeff, who had been retained before Everdail found me,
decided to do."

Sandy had made no contribution to the discussion.

He spoke, at last, quietly.

"I said, early in the adventure, that nothing was what it seemed to be,"
Sandy remarked. "This backs me up. But----"

"But--what?"

"Look at this, Mr. Whiteside--we are sure he made a try for the emeralds
in the seaplane he hired. He thought they were destroyed--at least he
had done all he could to destroy them. Then--why did he make another
try?"

"Maybe he wasn't sure he'd done what he intended," argued Dick.

"He had ruined them! Wasn't that enough?"

"My idea is that he learned--there was an accomplice on the yacht----"

"Mimi?"

"Perhaps! He must have learned that the real gems were not ruined at
all," Mr. Whiteside explained.

"Do you think his confederate threw the real ones overboard, in the life
preserver, with the ruined imitations tied to it?"

Turning to answer Larry, the detective hesitated.

"That doesn't check up," he said. "The confederate--Mimi--knew the
imitations! She wouldn't throw them at all. If she knew the real ones
were hidden in that life belt she'd have flung that. But we know that
the imitations went overside and were in the gum--as Sandy cleverly
discovered. So--that makes it all muddled up again!"

"I don't understand how the haunted hangar comes in," protested Larry.

"That's what I want to discover. It does come in--I'm sure of that! You,
and Dick and Sandy, can help, I believe. Two to watch the hangar, taking
turns, and with my aid whenever I can manage it. You, Larry, to perfect
your flying technique and be ready if I need you."

"It sounds good to me!" urged Larry, turning to his chums.

"Well, I say, let's reorganize," Dick had a twinkle in his eye. "You,
Larry, will be the sole member of the Sky Patrol--and Sandy and I will
be--er--the 'ground crew'!"

"That's a good description," the detective chuckled.

"All right," agreed Sandy. "Dick, you and I are the ground crew. As soon
as you're ready, Mr. Whiteside, we'll take hold!"




                             CHAPTER XXIII
                             LARRY "SOLOS"


Taking hold, for the "ground crew," required some argument with parents.
Mr. Whiteside seemed to have some magical way of overcoming objections
to possible night activity, however; and the next morning found the two
reinstated assistants riding with Mr. Whiteside on a 'bus bound for the
town nearest to the old Everdail estate.

Their morning work consisted of investigating the hangar, outside and
inside.

The caretaker raised no objections. He seemed entirely satisfied that
Mr. Whiteside was exactly what he claimed to be, and so Dick, who had
held some misgivings, accepted the man as a detective and worked with a
will to discover some clue to the means used by the "ghost" for getting
in and out of the hangar.

In that the trio failed, and had to give up until night would let them
return and establish a keen guard over the haunted structure.

Larry fared much better.

He found Tommy Larsen much improved in health, with his nerves again
steady.

"I don't feel uneasy about short hops," the pilot informed him. "I don't
think I'd want to take a long control job just yet, though. Now let's
see what Jeff put into you. Before I go up with you, tell me what you'd
do if you were really starting off alone."

"First of all," Larry said, "I'd go over to the weather display board,
to see what the flying conditions would be."

"You did learn!" Tommy was pleased. "Yep! That's important. Then----"

"I'd notice the windsock, while I'd go to my crate. If it wasn't already
running, I'd start the engine--being sure to repeat every syllable of
the 'mech's' words when he turned the prop."

"You wouldn't want any mistake on your part to have the juice on when he
swung that prop to suck in the charge--good!"

"Of course, if the airplane was on a cement apron in front of the
hangar, it would be all right to start the engine there. But in sandy
ground, or on a dusty apron, I'd be sure the tail wasn't pointed so the
propeller blast would throw dust on 'planes or on people."

Pilot Tommy Larsen nodded vigorously.

"Don't intend to be a dusting pilot, do you?"

"No, sir. Then I'd warm up the engine--by granny-golly-gracious! I
forgot something----"

"What?"

"Well, unless I'd seen him do it, before even the engine was started,
I'd want to be sure the 'rigger' of my crew would go over the crate and
wipe it with a soft rag, so any frayed wires would be noticed--and I'd
want to be sure he had inspected the 'plane either when it landed last
or before I'd take off."

"Jeff was a good teacher, I see. Go ahead."

Larry went through the explanation of his method of taxiing, with the
elevators up enough to keep the tail on the ground as he used the
throttle to regulate speed, and the ailerons to govern the wings and
keep them from being tipped up or down by wind or uneven ground, as well
as his idea of using the rudder to hold the ship on its straight travel
to the point of take-off and how he would turn.

"All right! If you know all that about getting set, you might as well
let me see you do it!" Thus Larry began his tenth hour of instruction.

That completed, and with a quiet compliment for the way he had made his
final check of the engine and instruments while the chocks were still
under the wheels, with a word of advice about not trying to lift the
ship off the ground in a cross-wind until a safe margin of speed was
assured, Larsen bade him return that afternoon. Larry, pleased, went to
his lunch, turning over in his mind the many things he had done, to see
if he had done any of them in the wrong way.

"I corrected the tendency of the wind to turn the crate as we taxied,
and I lifted her off and leveled for a couple of seconds so that the
prop could bring back flying speed before climbing."

He had also chosen a moderate climbing angle, keeping a watch for any
incoming craft as he went higher before banking and turning.

"I remembered to return the controls to neutral when I had the ship
flying just the way I wanted it to," he mused. "And I didn't
over-control. Maybe--maybe it won't be long before Tommy will let me
solo." It wasn't!

At three that afternoon Larsen informed him that he was to take up the
dual-control craft they had hired from a flying friend of the pilot's at
Roosevelt Field the second, on Long Island.

"All right--thank you. I'll keep cool--and do my best."

He walked to the airplane, standing before its hangar, determined to use
the after seat, as did most pilots flying alone in a dual machine, and
turned to Tommy inquiringly.

"Where's the sack of sand?"

"Did you think of that?"

"Yes, sir. If I am in the front and you are in the other place, and the
airplane balances and flies easily, there must be something to make up
the difference when you aren't along!"

"Bud--you'll get along!"

And when the sack had provided stability in the front place, Larry,
feeling a little anxious, but more about making mistakes under the
pilot's watchful eye in starting than about his performance in the air,
got the engine started, warmed up, checked, put the craft into the wind,
signaled for chocks to be pulled away, gave a spurt of the "gun" to
start it, accelerated speed till the ship began to want to take the air
itself, having remembered to use the elevators to lift the tail skid
free from dragging--and with a return of elevators to normal right away
to keep the craft level on its run--he drew back on the stick, widened
the throttle feed a trifle, returned the elevators to normal as he
attained the safe climbing angle, and was up and away on his first solo
flight.

In his whole life he had never felt such a sense of elation!

The whole fifteen minutes that he stayed up were like moments of
freedom--alone, master of his craft, able to control it as he
would--there is not, in the whole world, another sensation to equal that
of the first solo flight of a youthful pilot who combines confidence in
himself with knowledge of his 'plane and how it responds.

The heavens were his!

No bird ever was more free.

And when he made his landing, perfectly setting down on wheels and
tail-skid as Jeff had taught him, "I wish all my pupils were like him,"
said a flying instructor who had been watching. Larry, doffing his tight
"crash" helmet, overheard.

It was the most cherished compliment he could wish.

And that marked the beginning of ten days of flying, sometimes with
Tommy to give him the evolutions of recovering from side-slips, skids,
tail spins, and other possibilities of flying, none of them hazards at
sensible altitude, and with a calm mind guiding the controls. At other
times "stunts" were taught, not to make him a daredevil, but because, in
flying, an airplane sometimes gets into positions where the pilot must
know every possible means of extricating it. Solo, and with Tommy, Larry
became a good pilot.

And in all that time, his "ground crew"--got nowhere!




                              CHAPTER XXIV
                         A PUZZLING DEVELOPMENT


"Hooray!" Dick slapped Sandy's shoulder. "The 'man higher up' has come
down to earth! Here comes Larry!"

"You're a sight for sore eyes!" Sandy exclaimed as the youthful amateur
pilot joined his friends.

"I haven't seen much of you, I know." Larry sat down on the swing by
Dick on the latter's veranda. "Daytimes I've been studying rigging and
checking up on an airplane, because Tommy thinks a pilot ought to know
everything there is to know about his ship because he may have to do
things himself if he gets hold of a careless rigger."

"If the pilot didn't know the right way he couldn't say if his helper
was doing things the wrong way," agreed Sandy.

"But that hasn't kept you away evenings," objected Dick.

"Tommy has been very good to me, giving me his time, in his room, so he
could tell me all the 'fine points' he has picked up about flying."

"Sky Patrol's report received, considered and accepted," Dick stated.

"Now for yours," Larry smiled. "What has the Ground Crew done?"

"Watched, evenings, turn and turn about, till midnight," Dick told him.
"Mr. Whiteside took the day shift and came on to relieve us every
midnight."

"What progress have you made?"

"None at all!"

Sandy, responding to Larry, added:

"But you wouldn't expect anything to happen if you'd seen all the
reporters who have been 'hanging around' the old estate. Why, one has
slept in that hangar a couple of nights."

"No ghost with any self-respect would make a show of himself for
newspaper publicity!" Dick chuckled.

"Almost all we needed to do was to watch the reporters," Sandy said.
"But they have given up, I guess. There was only one out last night, and
he told me he thought the paper that ran that 'box' had played a trick
on the others and on the readers."

"That's good," Larry remarked. "Now the coast will be clear, the ghost
can walk, and I will be with my trusty comrades to trip him up."

"It seems queer to me," Dick spoke. "I've thought a lot about it. The
fellow who played ghost must be searching for something. What can it
be?"

"The emeralds?"

"But he was there before they were lost, Dick," Larry objected.

"That's so, Larry."

"Here's something that just came to me." Sandy bent forward in the
lounging chair. "Nothing has happened at night, for ten days. But all
that time, Mr. Whiteside has been on the 'day watch,' as he calls it."

"Golly-gracious!" Larry exclaimed. "Do you think?----"

"When Jeff flew us there, the first time, there seemed to be somebody in
that hangar when we started in," Dick added to Sandy's idea.

"You're right," Sandy admitted. "By the way, Jeff is back at Bennett
Field, taking up passengers for hire again."

"I'm not worrying about Jeff." Larry was caught by the suspicious action
of their "detective" in taking the day watch while nothing occurred at
night.

"What do you think of going out there to the hangar now?" he asked.

They thought very well of the idea.

It was close to noon when the 'bus deposited them at the town from which
they had to walk to the estate.

Strolling down the quiet street toward the main highway, Sandy's alert
eyes, always roving, caught sight of the estate caretaker. They hailed
him and ran to the corner where he had turned to wave to them.

He greeted them sourly. Plainly the caretaker was out of sorts.

"Humph!" he grunted. "More dern amachoor detectives!"

"What makes you say that?" Sandy's grin of salutation changed to a look
of hurt surprise.

"Why wouldn't I say it? Ain't it enough I had reporters an' all
rampagin' through the place without you three got to come, on top o'
that Whiteside feller and Jeff----"

"Mr. Whiteside--and Jeff?" repeated Larry.

"Yep! Nights it's been bad enough--now it's daytimes! Ghosts! Reporters!
Snoopers! And now you fellers in the daytime!"

"What about Mr. Whiteside--and Jeff?" Dick wanted to get to the bottom
of a startling situation.

"Well, if you must know--that Whiteside feller was there, as per usual,
and along come Jeff, limpin'----"

"Limping? Was he hurt?"

"Had his foot tied up, Master Larry. Said he was flyin' and his power
quit and he had to come down in a bad spot and a lot more."

Once started on his troubles and their cause, the caretaker needed no
more prompting. Jeff, he went on, had met Mr. Whiteside and said that if
he wanted to fly he'd have to go in that other thing that they put in
the water----"

"The hydroplane boat?" Sandy broke in to ask.

"No, the ampibbian----"

"The amphibian!"

The man nodded as they walked down toward the highway. After he helped
the others to get the water-and-land 'plane onto the field, he grumbled,
and had turned the propeller blades till his arms ached, the
superstitious pilot, saying he had stumbled and fallen that morning and
knew something would go wrong, had decided that they had no time to
repair or find the trouble in the amphibian.

They must get going, he reported that Mr. Whiteside had declared, and
Jeff had argued that if he had a six-B slotted bolt, he could fix his
motor.

"I never did hear of a six-B slotted bolt--or any slotted bolt,"
declared Dick, while Sandy and Larry assented.

"Neither did the hardware man here in town after that Whiteside feller
gave me five dollars to walk in the four miles and--back!"

Dick consulted his comrades with his eyes.

"That sounds to me like sending a new machine shop hand to the foreman
for a left-handed monkey wrench," he chuckled. "They've played a
joke----"

"That doesn't fit in," argued Larry. "A bandaged foot, a limping pilot,
an engine that wouldn't start--and sending this gentleman on an errand
that would take him away for a good while----"

"Where did Jeff say he set down?"

The caretaker turned and scowled at Sandy.

"He never set down nowhere. He leaned against the hangar!"

"I mean--where is his own airplane?"

"He never told me."

All three comrades wished heartily that Jeff had revealed the
information. Since he had not, each cudgeled his brains for some likely
place within walking distance of the estate.

"That 'six-B slotted bolt' makes me think his engine hasn't anything
wrong with it at all," Larry stated, finally. "Furthermore, I think he
put down his crate in some handy--good--spot!"

"A crackerjack pilot like Jeff could get in on a pretty small field,"
Larry argued. "One place I can think of that isn't a bad landing spot is
the fairway of the ninth hole on that golf course yonder." He indicated
the grounds of a golf club. "It's away from everything, and he might fly
over the course, see that no foursome or twosome was likely to get there
for some time--" Dick nodded, agreeing; but Sandy shook his head.

"What bothers me," he stated, "is that if his engine is all right, Mr.
Whiteside would have met him and gone in Jeff's ship."

"Unless--unless they wanted to make a water landing!"

"Golly-gracious, Dick! I think you've found the reason----"

"But, Larry--why wouldn't they use the hydroplane boat?" Sandy was not
convinced.

"I think the amphibian would be quicker--and maybe they don't want to
land but need the pontoons in case of----"

Dick, laying a hand on Larry's arm, stopped him.

"I have guessed the answer," he cried. "They wanted to get rid of this
gentleman," he nodded toward the caretaker. "Then they could search that
hangar----"

But they, themselves, had done that thoroughly! Larry made the objection
but Dick waved a hand to dismiss it.

"The ghost hadn't found anything. We hadn't!" he argued. "Maybe they've
decided there is something--and if it isn't there when they make a good
search, they think they know where else to look--and it's either in the
water--or over the water--or----"

"In the swamp where the seaplane crashed!" shouted Sandy, complimenting
Dick with a sound smack on his back.

"Then let's look on that fairway and see if the airplane is there, and
if the engine runs."

The airplane was there. The engine operated readily.

While they discussed these proofs of Dick's quick wit, the sound of an
airplane engine turned all eyes skyward.

"It's the 'phib'!" Sandy exclaimed.

"Come on--get in!" Larry urged. "I can fly this crate--and we'll see
what they're going to do!"




                              CHAPTER XXV
                              HIGH WINGS!


If he never did so again, Sandy lived up to his decision to turn over a
new leaf for once.

Usually impulsive, generally quick to adopt any new suspicion, he
surprised his chums by catching Larry by the coat and dragging him back
to the ground as his foot rested on the wing-step bracing.

"No!" he cried. "No! Larry--Dick--you, Mister! Come on, quick--under
these trees yonder!"

They stared at him.

"Don't you understand?" he urged. "Jeff will fly over his crate to see
if it's all right. He may see us. Come on!"

So sound was his argument that the others hurried with him to the
concealment of the nearby grove, after Larry had thoughtfully cut out
the ignition so that the propeller would not revolve if its observers
flew low enough to distinguish its position.

Well hidden, they learned how wise Sandy had been.

Coming closer as it dropped lower, the amphibian circled in a tight
swing over the fairway several times and finally straightened out,
flying toward the wind that came from almost due North on this first
cool day after a humid July week, and began to grow smaller to the
watchers.

"We'd better get that engine started, now." Dick left the grove.

"Let's be careful," commented Sandy. "They may come back."

"We can be warming it up and watching!" Larry urged.

"We don't need to hurry," Sandy insisted. "I think I know--at
last!--what this all means."

Three voices, that of the caretaker no longer grumpy, urged him to
explain. Too earnest to be proud of his deductions, Sandy spoke.

"When the hangar was first haunted, and we found chewing gum that the
ghost had put there, as we thought," he told an interested trio, "none
of us could work out any answer to the puzzle.

"But stop and think of these things," he continued, urging his two
friends to use their own imaginations. "The amphibian was old-looking
and didn't seem to be much good, and the gas gauge was broken, and the
chewing gum was quite fresh. That might look as though----"

"Some pilot was getting the 'phib' ready to fly and chewed gum as he
worked and put the gauge out of order to keep anybody from knowing he
had filled the gas tanks."

"Good guess, Larry! It's the way I work it out," Dick added.

"Go on, young feller." The caretaker was absorbed.

"Well," Sandy grinned, "the chewing gum disappeared! Supposing the
fellow we thought we saw vanishing really was there and got out some
way. He'd know, from Jeff landing us and our going in, that the
amphibian might not be usable when he'd need it----"

"So he went back and got the gum--but why?"

"He was getting that ready, Dick, for the emeralds--remember how Sandy
discovered the place the imitations were hidden?"

"That's so, Larry. Go on, Sandy. You've got a brilliant brain!"

"Oh, no," Sandy protested. "It just flashed over me--putting all the
facts together, the way I made up my mind I'd do."

He outlined the rest of his inference.

"That was proved--the seaplane coming out to the yacht proved that the
passenger who said he was a London agent, and wasn't at all, had changed
his plans. Well, say that he had arranged with Mimi, Mrs. Everdail's
maid, to have her throw over the jewels----"

"But she wouldn't make the mistake of giving a confederate the wrong
ones. She'd seen the real ones."

They were working on the check-up and warming of the engine as they
talked. Dick made the objection to Sandy's theory.

"She'd know that the man knew the difference too!" Larry added.

That could be true, Sandy admitted. But he argued that the girl must
have seen the captain take the stern life preserver to his cabin, and
might have guessed, even observed through a cabin port, what he did. In
that case she would have thrown over the life preserver knowing that her
confederate would put it in the seaplane. And he had done exactly that!

"But the passenger jumped with a different life preserver!" Dick was
more anxious to prove every step of Sandy's argument than to find flaws
in it.

"I think we found the life preserver that they might have had on board
the seaplane all the time. And the other one--we never thought of the
yacht's name being painted on its own things. So we took it for granted
that we had the real hiding place."

"You argue real good, young feller."

"Thank you, sir. Well, if that was true--and if it wasn't--why is the
ghost walking again in the very hangar that the seaplane wreckage is
in?"

That was a clinching statement.

"You're right. And the passenger, who has been out of sight, has been
haunting the hangar, trying to find the other life belt," Larry took up
the theory. "Mr. Whiteside must have guessed that, too, and he planned
today to make a good search and if he didn't find what he wanted----"

"He'd fly over that swamp and see if the other belt had fallen out of
the seaplane--and he'd need a pilot--so he got Jeff!" Dick put the
finishing touch to the revelation. "Larry kept Tommy busy, so Mr.
Whiteside got Jeff."

"Then we ought to be flying--the engine wasn't very cold--it's safe to
hop." Larry took a step toward the airplane.

"I still claim we needn't hurry," Sandy argued. "If we go too soon, they
will be sure to see us and give up."

"But they may find the life preserver if it's still there and get away
with the emeralds."

"If it's still there, Larry, it will take some hunting. Anyway, we
almost know their plans. If they don't find anything they will come back
to the hangar with the crate. If they do----"

"They may go anywhere," Dick declared.

"Well, I don't say not to follow them. But I do say let's take our time.
Isn't there some way we can work out so they won't be likely to discover
us?"

Larry stared. Then he nodded and grew very thoughtful.

At last he delivered a suggestion that met unanimous approval.

The airplane, with a more powerful engine and better flying qualities,
could go higher than the amphibian which was both slower and more
clumsy. To that argument he added the information that if the binoculars
they had first used were still where Dick had put them, in the airplane
pocket, they could find the ship's "ceiling"--the highest point to which
power would take it and the air could still sustain it at flying
speed--and from that height, in one look downward discover the truth or
falsity of their theory.

"If the 'phib' is flying low over the marsh, we can go off as far as we
can and still see it," he finished. "Then if they fly back to the
hangar, we can outfly them on a different side of the island and get
here in time to leave Jeff's crate while we go and see what they do.
They won't suspect that we're near, and if the caretaker goes with us as
a witness to check up our story and to help balance the fourth seat, we
can either come back if they do or follow them if they go somewhere
else."

Within half an hour, high in air, the airplane found its quarry!

With a cry of delight, unheard in the engine drone, Dick took the
powerful glasses from his eyes, passed them to Sandy and then rubbed his
hands vigorously to rid them of the chill of the high altitude.

Sandy had only to take one look when he located the object of their
flight, to know that his deductions had all been sound.

Close to the grassy, channel-divided marsh, flying in a sort of spiral
to cover every bit of ground, the amphibian was moving.

Sandy generously recollected the caretaker and sent back the glass.

Larry, informed by Sandy's gesture of the discovery, nodded, took a
second to jam his cap tighter, glad that it fitted so close that it
could partly save his hair from the blasting, pulling wind--he had no
helmet!--banked and leveled off into a course that would take them
straight away from the locality.

"I don't want them to catch us cruising," he murmured to himself.

After a short flight he came around in a wide swing, so that the
airplane was over the Sound and then crossed the marsh again from that
direction.

The report he got was that the amphibian was still flying.

But the next approach told a new development.

The 'plane beneath them had set down!

That caused Larry to determine to circle over the place. They had found
something, perhaps, down below!

When Sandy waved in an excited gesture, twenty minutes later, and
Larry's keen eyes saw the amphibian, a tiny dot, moving over the Sound,
he felt sure that the missing life preserver had been found.

Taking a quick glance at gas gauge, altimeter, tachometer and his other
instruments, he nodded.

"All right," he told himself. "We'll follow them and see what they do
and where they go."

On high wings the pursuit began.




                              CHAPTER XXVI
                                THE RACE


Judged by the theory they had worked out, the action of the men in the
amphibian indicated that they were flying away with something they had
found.

"If they had given up, so soon," Dick mused, holding his head low to
avoid the icy blast of their high position, "if they'd given up Jeff
would go straight to the hangar again. But they're going across Long
Island Sound toward Connecticut, just as the unknown person in the
hydroplane boat did with the other life preserver."

Larry, holding speed at a safe flying margin so that the sustentation,
or lifting power of the air, was greater than the drag of the airplane
as it resisted the airflow, let the nose drop a trifle, let the engine
rev down as he glided to a lower level where the air would not bite so
much. They would be able to follow quite as well, dropping behind just
enough to keep the line of distance between them as great as if they
were higher and closer over the amphibian.

With his glasses, Dick could observe and indicate any change of
direction or any other maneuver.

They had devised a hastily planned code of signals, very much like those
used by a flying school instructor giving orders to a pupil where the
Gossport helmet was not worn.

Dick, watchful and alert, lowered his chilled glasses and Sandy, keeping
watch, saw his right arm extend straight out from his shoulder,
laterally to the airplane's course.

Sandy repeated the gesture after attracting Larry's attention by a
slight shaking of the dual-control rudder which was still attached, but
which, on any other occasion, he had been careful not to touch.

"Left arm extended! Turn that way!" Larry murmured.

Gently he moved the stick to lower the left aileron, bringing up the
right one, of course, by their mutual operation; rudder went left a
trifle and in a safe, forty-five degree bank, he began to turn.

Almost instantly Dick again removed the chilly glasses, stuck his arm
out ahead of him with his forearm and hand elevated, and motioned
forward with the wrist and hand.

The signal was relayed by Sandy.

"Resume straight flight."

Larry, getting the message correctly, reversed control, brought the
airplane back to straight, level position on the new angle, and held it
steady, revving up his engine and lifting the nose in a climb as Sandy
gave him Dick's sign, hand pointed straight upward, to climb.

"What in the world are they going to do?" he wondered.

"Have they discovered us?" Dick pondered the possibility.

"I can't guess this one," Sandy muttered. "They started to turn one way,
then went on only a little off the old course, and now they're coming up
toward where we are."

The problem was not answered, either by the continued gain in elevation
or by the later change of plan.

"They're gliding!"

Dick, as he made the exclamation, gestured with his arm toward the
earth.

To Sandy's signal Larry cut the gun, keeping the throttle open just
enough to be sure the engine, in that chill air, would not stall, and
with stick sent forward and then returned to neutral, imitated the
gentle glide of the amphibian.

What it meant none of the three knew any better than did the half frozen
caretaker who wished very sincerely that he had never come.

"Sandy! Sandy!" Dick cried as loudly as he could. "They've done a sharp
turn--they're going back home I think!"

Larry did not need to have the intricate signal relayed, nor did he wait
to be told his passengers' deduction. Their own maneuvers had given him
a clue.

With the first change of direction and the following indecision that
showed in the amphibian's shifts of direction, Larry spelled a change of
plan on the part of its occupants. The resulting glide, enabling his
chums to speak above the idling noise of the engine, indicated a similar
possibility in the other ship--Jeff and Mr. Whiteside were talking over
plans.

He rightly decided that they had recalled sending the caretaker on a
foolish errand. They must get back and make some explanation or he would
suspect them, perhaps report to somebody else. They could not know that
he was shivering, crouched down in the last place of Jeff's own
airplane.

Now for a race, Larry muttered, almost automatically moving the throttle
wider as he prepared to alter their course.

It came to him, swiftly, that this would be both a race and a
complication.

Not only must they get the airplane back to the golf course and set it
down and have its engine still, themselves being hidden before Jeff flew
over it. Furthermore, they must get to the hangar and be somewhere near
the field when Jeff brought home the amphibian--or they would never know
whether he and his companion had found anything or not.

Larry had to do a little rapid mental arithmetic.

To avoid being sighted and identified when passing the amphibian, the
airplane must cut inland instead of making a beeline for the golf
course.

"That would make the return to their objective form a rough letter "L"
in the air.

However, at the far end of its flight the amphibian must turn inland a
similar distance to fly over the golf fairway. That made the flying
problem one of speed and not of distance traveled.

The airplane, selected for its wing-camber and span that gave it a low
landing speed and good sustentation, was not fast.

The amphibian was even more slow.

"Distance to cover, seventy miles," Larry pondered. "Our best speed,
Jeff said, once, was about seventy miles an hour. The 'phib' does sixty,
top."

He made his calculation.

"No leeway to get to the hangar--Sandy might, barely, because he was on
the track team, last school term. That is our only chance. But, at that,
it will be 'nip-and-tuck'!"

No air race can give the thrill of other forms of speed competition as
does the horse race, the motor boat or sailing race, the track meet or
the automobile speedway contests.

The distance is too great to permit spectators to observe it, the ships
scatter, seek different elevations, or in other ways fail to keep that
close formation which makes of the hundred-yard dash such a
blood-stimulating incident.

The automobile contest generally follows a course where watchers have
vantage points for gathering.

The sailboats or motor craft can be accompanied or seen through marine
glasses.

To air pilots, of course, there is plenty of excitement.

It is their skill, their ability to take advantage of every bit of
tailwind, their power to get the utmost of safe "go" out of engine,
wings and tail assembly, that keeps them alert and decides the outcome.

So it was in Larry's race, with Dick, Sandy and the caretaker.

It could not be watched or followed; but to the occupants of the ship it
was a thrilling competition with the mystery element adding zest; and
when, with a fair tailwind aiding him, Larry shot the improvised "field"
of the ninth fairway, making sure at cost of one complete circuit that
no one was there, playing, the thrill for them was not over.

Sandy caught Larry's idea even before the airplane had taxied to its
place, close to the original take-off.

"I'm off!" cried Sandy, coat flung aside, collar ripped away, as he
leaped fleetly along the soft turf. Not waiting to observe his progress,
Dick and Larry busied themselves getting the airplane tail around into
the same position it had originally occupied.

The engine had long before been stopped.

From the air, to an observer who had no idea that his craft had been
used, all should seem natural, Larry decided as he and Dick, with
Sandy's discarded garments, and with the caretaker ruefully grumbling,
chose a place of concealment.

Already the drone of the amphibian came from the shore side of the
field, and in a low, quick swing, followed by a zooming departure, Jeff
and Mr. Whiteside passed overhead.

"Now," Larry remarked, "it's up to Sandy."

"Yep!" Dick agreed. "And it will be a close thing for him."

"If he does!" grunted the caretaker.

For the answer they had to wait till dark.




                             CHAPTER XXVII
                           SANDY'S DISCOVERY


Although he was the central figure in an unusual situation, Sandy was
more puzzled than enlightened by its surprising development.

A footrace against a flying ship was novel enough; but the maneuver of
the amphibian was still more strange. It was baffling to Sandy.

Sandy gave up the race very quickly.

Hearing the approach of an aircraft he sought concealment under roadside
trees, continuing his steady trot. His heart sank as he identified the
amphibian making its swinging oval from water to land and around the
fairway and back.

"I can't make it," Sandy slowed. "It's all off!"

He knew that it was safe for him to leave his shelter. The "phib" was
past him in its zooming return from the golf course.

"Now we'll never know what they found, or if they found anything in the
swamp," he told himself dejectedly.

Then his attention was fixed and his mind became mystified.

"That's their crate, all righty," he muttered. "But--they're not landing
on the estate. I suppose they've come to see that Jeff's 'plane was
safe. Now they'll go on to Connecticut and we are defeated."

He came out onto the road, walking with bent head as soon as he had
caught his breath again.

For a moody few minutes he considered the wisdom of rejoining his chums.

"No," he decided. "When I don't join them they'll come over to the
estate. It might be a good idea to go on to the landing field and see if
the amphibian dropped off anything with a small parachute."

He pursued his way without haste. While he had been divesting himself of
his coat Larry had urged the caretaker to go on to his duties.

"I'll go on!" Sandy murmured more cheerfully. "I'll have a clear half
hour to myself. Maybe--without anybody talking and disturbing me--I
might think out some answer to all the queer things that have happened."

The failure of the amphibian to return to its home field he disposed of
by deciding that its pilot meant to take something to some rendezvous in
Connecticut, the one, no doubt, the hydroplane boat had made for.

The thing that came into his mind and stuck there, offering neither
explanations nor a solution was the mystery of how that man had
disappeared out of the hangar on their first visit.

"I'd like to find out how the 'ghost' gets in and out again," he
reflected.

Deep in the problem he looked up at a sound.

To his surprise, astonishing him so much that he stopped in the middle
of a stride, the lodgekeeper's gate of an estate he was passing opened
suddenly and Sandy found himself staring at the last person in the world
he expected to meet.

Facing him with a grin was Jeff!

"Hello, buddy," the pilot said, without any show of dismay.

"Why--uh--hello, Jeff!"

"On your way to solve that-there spook business?"

"I--" Sandy made up his mind to see if he could startle Jeff into a
change of expression and changed his stammering indecision into a cool
retort:

"I--met the estate caretaker in the village. He asked me to run on ahead
and tell you--and Mr. Whiteside--" Sandy watched, "--he could not find a
Six-B slotted bolt anywhere!"

"Oh, couldn't he?"

Jeff did not change a muscle of his face.

"Sorry he had all the trouble. We got the 'phib' engine going and I took
Whiteside off on a little private matter in that."

"Have you brought him back?"

"No. Set down in the little inlet, yonder." He waved toward the
shoreline concealed beyond the estate shrubbery. "It was closer to my
own crate--it's stalled yonder in the golf course."

"Oh!"

Yes--stalled! Sandy repressed a taunt and pretended to accept the false
statement.

"I hear Larry's been getting instruction off that-there Tom Larsen,"
Jeff turned suddenly on Sandy.

"Yes. Mr. Whiteside paid for it."

It would do no harm, Sandy thought, to let Jeff know that his fellow
conspirator, if that was Mr. Whiteside's real standing, was not playing
fair. "When people who may be wicked turn against each other, we learn a
lot," Sandy decided.

He failed in his purpose.

"Tommy's a good pilot," Jeff admitted. "Well--I'll be on my way. See you
at the next air Derby!" Jeff grinned at his joke and walked on.

So did Sandy.

While he hurried on, pausing only to collect a "wienie" and roll for
lunch, Larry and Dick saw Jeff approach across the green of the fairway
and took cover.

"He's inspecting that airplane--I hope we didn't leave any clues!"
whispered Dick.

"He's feeling the engine cowling--he wonders how the motor stayed so
warm," Larry retorted under his breath. "Now he's looking around--get
down low, Dick--well, he's shaking his head. Now he's in the cockpit.
There! He caught the spark on a compression stroke--used his 'booster
magneto.' There goes the engine."

And, from the descent of Jeff, to give the ground careful inspection to
the moment when he gave up his own baffling puzzle and took off, the
youthful amateur pilot reported to Dick, from a spy-hole in the
greenery.

"I wonder if Sandy knows Jeff has come on to take his airplane off,"
Dick mused.

"It's safe to go and see. If Mr. Whiteside is on the estate it will look
as though we came out extra early. Besides, I'm hungrier than Little Red
Riding Hood's wolf. Come on!" Larry led the way from the golf course as
he spoke.

Sandy, long since safe at the hangar, began to work out his puzzle.

"Somebody was in this hangar the day Jeff made his pretended forced
landing," he told himself. "We saw him. It wasn't a mistake. We all saw
him and that proves he wasn't just a trick of light in the hangar."

More than that, he deduced, the man had vanished and yet, after he was
gone, there had come that unexpected descent of the rolling door which
had first made them think themselves trapped. Sandy argued, and with
good common sense, that a ghost, in broad sunny daylight, was a silly
way to account for the man. He also felt that it was equally unjust to
credit the drop of the door to gravity. Friction drums are not designed
to allow the ropes on them to slip, especially if there is no jolt or
jar to shake them.

"But the switches that control the motor for the drum are right out on
the wall in plain sight," he told himself, moving over toward them,
since the rolling door was left wide open when the amphibian was taken
out. "Yes, here they all are--this one up for lifting the door, and down
to drop it. And that switch was in the neutral--'off'--position when we
were first here--and it's in neutral now."

He tapped the metal with the rubber end of his fountain pan and then
shook its vulcanite grip-handle, to see if jarring it caused any
possible particles of wire or of metal to make a contact.

"That's not the way it's done," he decided.

He stood before the small switch panel, considering the problem.

His eyes, in that position, were almost on a level with the pole-pieces
to which wires were joined to enable the switch metal, when thrust
between the flat pole contacts, to make contact and complete the
electrical circuit.

"Hm-m-m-m!" Sandy emitted a long, reflective exclamation.

"I never saw double wires--and twisted around each other, at that," he
remarked under his breath. "No--I'm not quite right. The two wires
aren't twisted around each other. One wire is twined around the other."

He traced the wires down into the metal, asbestos-lined sheathing cable,
and was still not enlightened about the discovery. It was not necessary
to have two wires. One was heavy enough for the hundred-and-ten volt
current that came in from the mains.

"That wire, being twined around the other, makes me think it was
added--after the first one was put in," he declared.

"I wish I could trace it," he added.

He tried.

Sandy, when he turned around, ten minutes later, knew all that the
inside of the haunted hangar could reveal.

Another five minutes, concentrated close to a certain spot on the
outside of the building, gave him his final clue.

But instead of waiting to tell his chums his great discovery, instead of
keeping vigil, Sandy went away from there as fast as he could walk.

All afternoon he was as busy as a boy trying to keep ten tops spinning!




                             CHAPTER XXVIII
                          NIGHT IN THE HANGAR


Never was a returning prodigal greeted with more delight than was Sandy
when, close to dusk, with a parcel under his arm, he joined Dick and
Larry inside a little Summer house in the Everdail estate grove.

"Where have you been?" demanded Larry. "We hunted high and low! We
thought something had happened to you when we saw Jeff fly his airplane
away, came here and didn't locate you."

"I didn't mean to scare you. But I've been awfully busy."

"Doing what, Sandy?"

"Following farmer boys down hot, sunny furrows while they picked
vegetables for market, Dick."

"Following farmer boys? What in the world for?"

"To ask them if their fathers would buy a book on family crests and have
their coat of arms thrown in free."

"Have you lost your head, Sandy?"

The youngest Sky Patrol grinned, and shook his head in question.

"No, Larry. It was an excuse to get them talking. I got the book out of
Mr. Everdail's library and used it to make them think I was a
subscription agent--so I could ask questions."

"Ask--questions?"

Dick and Larry spoke together.

"About what?" demanded Larry, and Dick nodded to show he wanted an
answer also.

"Well--about who is related to who, and family scandals, and who works
for this one and that one--just 'gossip'."

Dick caught the impish youth by his shoulders and shook him.

"Stop that! Tell us where you've been and what you did? We've worried
ourselves sick, nearly."

"I have told you."

Then he became really serious.

He had been all over that section of the farm-lands, he asserted, to see
if he could pick up any information that would give him some connection
between either Mr. Whiteside or Jeff, or the mysterious seaplane
passenger--and Mimi or the yacht stewardess.

"If I knew that, I thought we could start patching clues together," he
finished. "Because Jeff has a lot to do with this mystery."

"I think you're right," Dick agreed. "But what started you off on that
track?"

Taking an arm of each, Sandy led them, wordless, up the path.

Spying carefully to be sure that Mr. Whiteside was not in sight, and
being certain that no one else was watching, Sandy led his chums into
the hangar.

Across to one of its longer sides he led them.

"These are the switches that work the rolling door motor, you remember?"

"Yes, Sandy. What?----"

"Look at them before it gets too dark, Dick. Do you see anything
strange? You know as much about wiring circuits as I do. We both built
amateur short-wave sending and receiving sets. You, too, Larry. What
isn't right about the switches or--the wires?"

Thus guided, both studied the switches.

All Larry saw was that the wires were of a braided form.

"But--are they?" He pulled a wire out a trifle from the sheath.

Then his comrades observed what had first attracted Sandy's attention,
puzzled him and led to further search.

One wire, somewhat lighter in its insulation than the other, was wound
around the heavier one. They traced it, as Sandy had done. It seemed to
wind on down, as did others he showed, from each switch-pole, into the
protective sheathing of metal and insulation; but none really were wound
any further. From there on down, they ran behind the other wires!

"Bend down, close to the floor," urged Sandy. "See all the dust and lint
piled up?" He scraped some aside.

"My!" exclaimed Larry. "Golly-gracious-gosh-gravy-granny! The wires come
out from behind the sheath and turn along the floor, close to the
wall--and there's dust all covering them! No wonder we didn't notice
them."

"Where do they lead to?"

"Follow the dust line, Dick," Sandy urged.

Back along the hangar wall they crept, until they came up to the small
wooden cupboard with its dusty, frayed protecting burlap across the
front. Under the cupboard boards the wires ran well concealed by more
dusty lint which seemed to have been swept into the corners by the lazy
act of some cleaner.

"Inside here--but don't use a light--inside here, there are smaller
duplicate switches for the electric light arc and the motors," Sandy
informed his breathless, admiring cronies.

They easily proved it. More, they located the wiring in the dusk.

"But how does Jeff get in and out of here?" asked Dick.

"We have to go outside so I can show you what I discovered."

Trooping around to the rear, at one corner, Sandy bade them bend down
and examine the bolted metal sheaths, large plates of sheet iron, that
composed the walls of the edifice.

"I don't see anything," objected Dick, dejected that he had not been as
quick of wit as had his younger chum. "But, then, you saw it first by
daylight."

"I did, that's so." Sandy gave them all the information he had. "I saw a
break in the paint, only up one-half of this big plate of iron.

"The bottom half pushed inward," he explained. "It has hinges fixed to
the inner part so it will lift up into the hangar and we can creep in."

He proved it, and they followed him through the fairly low orifice.

"Now," he said, as Dick, last to crawl in, cleared the edge of the
metal, "see how clever this is--the inside of the two plates it has to
come down against are fixed with something soft--I think it's felt--to
keep the plate from clanging. It fits so well that the only way I found
out about it was by the sun making the dent in the paint show up a few
little bright worn spots of bare metal."

They complimented him with no trace of envy.

"Do you think Jeff did this?"

"Well, Larry, he said he flew over here at night. He chews gum and we
saw how fast he chewed the day he pretended to be forced to land here.
He knew all about the emeralds. And the most telling thing against him
is that his wife--Mimi--is Mrs. Everdail's maid and was on the
yacht----"

"Mimi his wife?"

Sandy nodded at Dick's exclamation.

"Miss Serena saw her run in her uniform," contributed Larry.

"How did you discover she was Jeff's wife?"

"Talking to farmer boys--what they didn't know, they found out from
their older sisters when any of them were picking up early potatoes or
snipping asparagus or digging up onions."

"My--golly--gosh--gracious----"

Sandy agreed with Larry's exclamations but urged his chums to leave the
hangar: they knew all it could tell them. He wanted to replace the book
he had used and get away from the hangar for awhile.

In the old, disused house, to which Mr. Whiteside had secured a set of
keys for them so they need not hang around the grounds until there was
work to be done, they talked in low tones. Sandy believed that Jeff had
coaxed his wife to put acid on the gems in the London hotel, as had been
done.

"He might be as much of a fanatic as that," admitted Larry, but not with
any great delight--he had always liked Jeff. "He is as superstitious as
a heathen."

"But the maid knew those weren't the real gems!" Dick remarked.

"How do we know she did?"

"That's so. But somebody said she did, or thought she must know the real
ones."

"That doesn't prove she did, Dick. The real ones were hardly ever
removed from safe deposit," Sandy argued.

"Then why did she throw over that life preserver?--" and as he began the
inquiry Larry saw the answer.

"She--saw--the--captain hide--the real gems!" he finished.

"Jeff didn't use the amphibian, though. And he brought us here and
induced us to aid him, saying we were helping Mr. Everdail."

"Yes," Dick supplemented Larry's new point. "Another thing, Sandy, that
doesn't explain why he'd take three boys and fly a ship he could never
use on water--with an amphibian right here."

"I am only saying what I believe. I don't know very much. But what I do
know points to Jeff."

"But he didn't get the life preserver."

No, Sandy agreed, Jeff did not expect to do that. He argued that Jeff
must have planned to superintend the affair, while the man in the
seaplane with Tommy Larsen secured the gems, whereupon Jeff could chase
him, probably turn on him and get the emeralds, and then pretend on his
return that the man had gotten safely away.

"But we don't need to guess," Sandy said. "Before I began asking
questions I met Jeff on the way here." He explained what made him
suspect the man who said he must repair his "stalled" engine with a bolt
that he knew was not made--a slotted bolt. "I slipped down across that
estate to the inlet and saw the amphibian. And Mr. Whiteside was in it,
supervising the filling of its tank!"

"Then he means to get away with Jeff----"

"No he doesn't!" said Larry, sharply. "Here he comes onto the lawn!"

Pretending to be unaware of the arrival, the Sky Patrol issued from the
house.

They saw that Mr. Whiteside carried a life preserver. In black on its
side was painted "_Tramp_, New York."

"Well, Sky Patrol--and Ground Crew," he hailed them. "We are going to
see some excitement at last!"

"Why?" asked Larry.

"How?" Dick amended.

"We are going to trap the real culprit."

"How?"

"By watching in and around the hangar to-night--and this time our bait
will be this life preserver that I discovered in the swamp. I guessed
the 'ghost' was searching the amphibian and the seaplane for the right
life preserver. I devised a plan to get rid of the caretaker while Jeff
and I made a complete, exhaustive search, this noon. We found nothing;
so Jeff flew me over the swamp and we got--this."

"Let's open it!" urged Sandy, all his former suspicions gone in his
eagerness. "We can take out the emeralds and then put the empty doughnut
in place."

"No. We won't tamper with it. I want to deliver it, intact, to Atley
Everdail. His is the right to open it."

"Isn't it a risk?" Sandy objected.

"No. Dick will watch inside the hangar, Larry and I by the doors. Sandy
will be in or near the amphibian. If Jeff is the culprit we'll soon
know--if he had a confederate we will discover that, perhaps, also."

"If it isn't Jeff at all--and I hope it won't be," Larry said, "if it
turns out to be the seaplane passenger who discovered that in his terror
he chute-jumped with the wrong belt, and he comes to hunt the right
one----"

"Or if it is Captain Parks, or his mate, or a seaman--" Mr. Whiteside
began to chuckle as he led them toward the dark loom of the hangar,
"Or--even if it turns out to be--me!--"

"Did you walk under a ladder, today, sir?" asked Sandy seriously.

"No. Why?" The man stared at him through the night. "What makes you
ask?"

"Because Jeff did--he walked under a ladder where a man was pruning a
tree as he came to the gate of the estate next door."

"Hm! Then--if he's as superstitious as he makes believe," Larry laughed,
"he'd better watch out."

"He had that!" Sandy agreed.

And Dick, as they entered the hangar, rolled down the doors, set the
switch at neutral and he was alone with Sandy in the pitchy blackness,
echoed the sentiment.

A new idea flashed into Sandy's mind.

"Do you know," he spoke through the darkness. "Dick, we're not watching
that amphibian at all! If Jeff did come here and managed to get away,
he'd go straight there and fly off."

Dick agreed, declared that with Larry and Mr. Whiteside within call he
dared to wait in the hangar alone, and Sandy, going out through the
secret way, encountered Larry and the detective, consulted them, had
their sanction for his idea and hurried off toward the next estate.

Thus divided up, the Sky Patrol spent dull hours waiting.

But patience is always rewarded!




                              CHAPTER XXIX
                             SANDY'S TRAIL


Wearisome though his vigil was, Sandy made the best he could of it by
going over all the events that had happened.

With his chums he had become friendly with Jeff at the newly opened
municipal airport. Jeff had flown them to the old estate, pretended that
his motor died, simulated a forced landing, then explained it all in a
way that looked sincere enough at the time--but now!----

Jeff had been the one to accompany Larry to the wreck of the seaplane,
and to bring the life preserver back, when he took Tommy Larsen to the
emergency hospital.

One little thing bothered Sandy at that point in his musing: why had
Jeff not made away with the life preserver at once?

"Oh, but he hadn't seen his wife then," he thought. "Mimi told him her
news, about seeing the captain of the yacht hide the real jewels--and
being an airman, he hadn't known that all yacht equipment has its name
painted on it in case of a wreck at sea."

Skipping many other things that seemed to point out Jeff as the
ringleader, deceiving his employer and war buddy, Mr. Everdail, Sandy
came down to the present suspicious circumstance.

"Jeff left the amphibian here on purpose. Of course he knows that Mr.
Whiteside won't leave the real jewel 'preserver' unguarded here, but he
must know the plan to have it in the hangar. He thinks he is clever
enough to outwit us all--but Jeff," he addressed the imaginary image of
the pilot, "you walked under a ladder, today. Don't forget how
superstitious you are. And--this time--it is an omen, and no mistake."

He cut short his meditation and listened to the sound of oars in the
inlet.

Was Mr. Whiteside coming--or Jeff?

His uncertainty was not maintained for long.

Making no effort to be quiet, the oarsman sculled to one of the steps
arranged for embarking on the amphibian in water, looped a line around a
strut to hold his boat against the drift of slack tide and a slight
wind, and came onto the amphibian.

Sandy, crouched low in the passenger's cockpit, hoping Jeff would not
notice him, was dazzled by the beam of a searchlight pocket lamp which
Jeff flashed around.

"Hello!" he exclaimed, surprised. "What are you doing here?"

"Don't you know the plan?" Sandy wanted to take advantage of Jeff's
momentary indecision: perhaps he would "give away" something.

"Yeah! I know what Whiteside planned. But he didn't plan for anybody to
be here. What's the need?"

"In case the--ghost--got away from the others and knew this airplane was
here."

Sandy got a shock of surprise.

"Why, that-there is so! And if the gas-boat come and filled up the
tank--I sent it, this afternoon and that was what Whiteside stayed here
for, to see that the 'phib' got gassed and oiled up--the--ghost--could
use it, if that-there ghost was a pilot."

"That's what we thought."

Jeff chuckled rather sourly.

"Yes," he said. "And you suspect me. I know you have, ever since the
start of this business----"

"Oh, yes--I did." Sandy thought fast: he decided to clear Jeff's mind.
"But don't you remember that I turned over a new leaf?"

"I wish your buddies and that-there Whiteside would do as much, then."

Sandy could not find anything to say.

"It's funny," Jeff remarked. "This-here psychology I've read about ain't
so far wrong when it says that folks who gets the wrong slant on a thing
comes to believe it so strong that even the truth looks like a fib to
them."

Sandy said nothing.

"Oh, well," Jeff turned and found his way back to the rowboat. "Time
will tell. I seen a flock of birds circle over my head this afternoon
and that-there is a sure sign of good fortune. I'll come out cleared!"

With no further word he sculled away.

"Don't forget," he called over his shoulder, "if you can suspect me, I
can suspect you--and Whiteside--and Dick--and Larry!"

Sandy, without reply, was already quietly undressing.

When the boat touched the wharf Sandy was a tiny figure moving with
careful strokes through the water, screened by the amphibian as he swam
for a sandy outcrop of the shore not far beyond the flying craft.

The dark figure of the pilot, moving across the estate shore paths had,
at a good distance behind it, a shadow. Sandy had managed to hold his
bundled clothes enough out of water to be fairly dry.

Over to the disused estate the quarry and its watchful shadow moved.

The pilot turned up a slope and climbed the smooth turf.

Sandy, waiting until he got to a shrubbery, moved so it was between him
and his quarry. He, too, crossed the ascending turf.

It startled Sandy to see Jeff turn in at the old house, climb the
veranda steps, cross the porch to the door--and go in.

Sandy stayed behind some shrubbery.

Jeff could watch from the doorway. He might see a figure in the open
space of the lawn around the house.

He thought he guessed Jeff's ruse.

The pilot, he reasoned, would go through the house after seeing that no
one seemed to be following; but to be doubly sure he would go on to the
front, coming out there, or to the side opposite where he had entered.
Sandy matched his plans to the chance. He went, Indian-still and
crouched, to a point where an ornamental tree would be in line with his
movement from the side door, then in that shelter moved back to the
hedged path, bent low and ran down to a cross path that took him to
another point of the grounds.

From that he could observe the whole lawn around the house.

But, when a half hour had elapsed and no one had come out, he was
puzzled. Had his maneuver been executed too late? No, Jeff could not
have gotten out of sight because the lawn was too wide to cross in the
brief time Sandy used up.

"He's in the house--doing what?" he wondered.

He did not dare to find out. That "what" might be answered by
"watching!"

Once he thought he caught a glint of light in the library window; but it
could have come from a high beam of some automobile headlight, on the
distant highway that passed the estate.

So Sandy watched and waited.

Therefore he did not see the dark figure that emerged cautiously from
the grove and, with intent, careful gaze, studied the hangar.

The ghost was getting ready to walk!




                              CHAPTER XXX
                      DICK ENCOUNTERS THE "GHOST"


When Dick had tried crouching, sitting on his heels, walking and every
other device he could think of to end the interminable difficulties of
trying to pass time with nothing to do and nothing under him but the
hard cement hangar floor, he began to wish he had never met Jeff or
gotten into the adventure at all.

He resolved, then and there, never to become a detective.

Countless times his nerves had been pulled by sounds which turned out on
second thought to be only the contracting of the hot metal, subjected to
the sun all day, as the evening breeze robbed it of its warmth.

No wonder that he failed to react to a slight clinking, hardly more than
would be made by the scratch of wire in a lock.

But the shrinking of metal had made intermittent noises, sharp and not
repeated.

This sound, so insistent, so prolonged, began, at last, to make an
impression. "Now what can that be?" he wondered, becoming strained in
his effort to make his ears serve him to the fullest degree.

"It can't be a rat's claws," he decided. "There aren't any rats. There's
nothing to draw them, here."

At the emission of a sharper click from some unlocated point he felt his
spine chill, his nerves grew tense and a queer, uneasy feeling ran over
his muscles, an involuntary tremble.

"What could make such a sound?" he pondered.

Then he drew his legs in under him as he sat with his back against the
metal sheathing of a corner.

The small, side door, toward the Sound shore, was opening!

That was a complication for which nothing had been planned. Larry and
Mr. Whiteside, Dick knew, were lying in the shadow of the hedge behind
the hangar, watching the cleverly devised back entry way.

Because it had been supposed that the "ghost"--Jeff--or whoever it was,
would use that means of getting in, Dick's own position had been chosen.
He had selected a place sharply diagonal in direction from it. In his
corner he could not be seen in the beam of a flashlight from the small
cupboard unless its user came all the way out: otherwise the sides would
shape the path of the light so it would not come near him.

But a man or ghost entering from the side, and playing any light around,
would show Dick fully exposed.

The worst of that was that there was no rear guard flanking that door!

"Well," Dick thought. "I can only wait and see what happens--and be
ready to chase if I am discovered. Maybe I can catch and hold the
'ghost' till the others get to us."

Careful not to scrape his soles in the cement, he gathered himself into
a crouching, compact, alert figure.

Dim and hardly distinct to his straining eyes, there seemed to be in the
slightly lighter gloom of the floor where the door opened, a shadow.

It might be an illusion of his taut nerves and tense mind, Dick decided.

He could not see out through the opening because he was almost in a
straight line with the wall on that side.

He waited, becoming shaky with the strain, for what seemed like a
dragging eternity.

The intruder must be scanning the landscape, judging conditions, he
guessed.

When it seemed that he could not stay as he was another instant, the
door was slightly moved, and then softly closed. So quiet was the
operation that he did not hear the latch click. He had detected no
change in the color of the door itself as it hung, slantwise to his
view, and he heard no sound of feet on the cement.

That meant nothing fearful or horrifying to Dick.

Rubber soles and a dark suit covered the logical explanation.

"Still, I should have seen his face--maybe a mask, though----"

At any rate, he knew that he was not alone inside the edifice, and if
Dick's common sense was too great to let him think of uncanny spirits,
the sense of danger supplied chills and thrills a-plenty.

A faint, glowing, bluish light broke out.

It threw no beam, only a sort of dull phosphorescence; but Dick's quick
eyes ran instantly to its source--some small flashlamp covered with
colored cloth, a handkerchief, perhaps.

Behind that silhouette, because the light was aimed in the direction
away from Dick, he saw what caused him to emit a revealing gasp.

The figure silhouette between him and the glow wore a dress!

"A woman!" gasped Dick, and at the same instant the figure whirled, Dick
leaped up, the light went out and Dick rushed blindly forward.

A hand fumbled with the catch: that located her.

In his rush, Dick's arms were carried around the shoulders he could not
see. Like a serpent, sinuous, tense, powerful, the woman squirmed around
in his arms.

He tried to hold her with one hand as he strove to open that door with
the other, while he took the beating of her furious hands on his bent
face.

The door catch yielded--their wrestling, struggling weight drew it
inward.

"Help--this way!" screamed Dick.

And he clung like a terrier to a tigress!




                              CHAPTER XXXI
                        A TRIUMPH FOR THE ENEMY


Sandy was first to hear the call and locate it. The others, not
expecting a cry for help from within the hangar until they had seen some
one go in, when Dick would be only a sort of surprise attacker while
they proposed to make the capture, Larry and the detective were confused
for an instant.

Then, recovering, and supposing Dick had called from close inside the
hangar, they took the quickest way in, and interfered with one another
at the small opening in the plates.

Sandy, dashing toward the hangar, correctly supposing Dick had called
from its smaller doorway, did not see Jeff emerge from the old house and
start on a run in the same direction.

Dick, clinging with all his strength to a wiry, supple powerful body,
strove to keep that hold while he captured the hands that were pounding
at his neck and averted face.

Hot, quick puffs of breath fanned his cheek.

Hissing, sibilant gasps marked the throes of the struggle.

Unexpectedly the figure went limp.

Dick clung. He heard the aides coming in through the metal opening. He
caught the pound of Sandy's approaching shoes.

But he did not believe he had made his captive so tamely surrender.

He realized that with a hand at her side the woman was striving to get
at something in her skirt.

He slipped his arm down lower so that his hand encountered her wrist.

That lessened his ability to hold with the arm that was already aching
from its prolonged strain. His hand gripped convulsively in the folds of
the dress at the back; but his grip was not as tight as it had been
because his mind was concentrated on stopping that other hand!

He felt a knee coming up.

Involuntarily he shrank back from a possible kick in some vital spot.

Like a cat the figure squirmed, a heel, small and sharp, came down on
his foot. He grunted and winced and the figure broke his grip.

Pushing him, leaping backward, only to catch balance, the form wheeled
on agile feet and ran for the grove.

Sandy, within sighting distance, cut into the wood to intersect the path
of flight.

Dick pounded after the woman.

From the door of the hangar Larry and Mr. Whiteside emerged to join the
chase.

"If I could have held her one second more!--" panted Dick.

"Her?" cried Larry.

The grove had prevented him from seeing the escaping figure.

"It was Mimi, I guess!"

They all disappeared into the grove, and Jeff, coming rapidly closer,
paused to listen to the sound of the pursuit.

A smile, inscrutable in the dark, crossed his face, twisted his lips. He
turned into the hangar.

Down the wood's path raced Dick, Larry slightly ahead of him, the
detective, older and not so quick, bringing up the rear.

"Scatter!" cried he. "She has turned off!"

"Here she is--" Sandy shouted, but a crash indicated that he had
stumbled or missed his footing on slippery sod or pebbles.

The chase turned toward him.

Recovered, he dashed in pursuit of the woman.

Their quarry was fleet, clever and terrorized: she led them always
toward the water, down hill.

Sandy, having hurt his foot somewhat in his stumble, was quickly out of
the race.

He decided to go back and see if the hangar, with its door wide, was
still deserted. Sandy had a misgiving that the woman might be a decoy
and that the hangar ought to be watched.

As Dick passed at a slight distance, Sandy told his idea.

"That's--so," panted Dick. He decided that the other two must be both
fleeter and more agile than he, with his fat; so he returned with Sandy,
to a point where they saw that the door was in the same relative
position they had left it--wide.

"I don't think we need to stay here--both of us," Sandy said. "And if
Jeff went into the house, he may have come out. Suppose he plans to get
hold of that life preserver, and the woman was sent ahead to get us all
away--" He considered that, then went back to his original idea, "Then
it would be a good thing for me to get back to where I can watch that
amphibian."

Dick agreed.

He went inside the hangar, closing the door, and resumed his vigil.

In a short time two others returned, to knock on the door and to inform
Dick, when he opened it, that the woman, clever planner that she proved
herself, had arranged the small motor-boat of the estate so that its
engine was going; by a ruse she had gotten far enough ahead of them
while they stopped to "capture" her discarded coat after she had cried
out as if she had stumbled. That enabled her to get to the boat. They
had no way to overtake her as she swept out of the inlet. Evidently she
had started the boat motor in the afternoon while they were away, or
they would have heard the roar of the start though no one had noticed
the softer purr of it as it idled.

Then they went into the hangar and Mr. Whiteside, listening to Dick's
report, from Sandy, of Jeff's movements, swung his flashlamp around.

From each came an amazed, horrified gasp.

The life preserver was gone!




                             CHAPTER XXXII
                            A DOUBLE PURSUIT


"Keep your heads, boys," counseled Mr. Whiteside.

"We will--but come on--Jeff's making for the amphibian--let's----"

"Sandy went back to guard it," Dick told Larry who had spoken.

"Not alone is Sandy on watch, but I arranged to have Tommy Larsen bring
his airplane to the golf green Jeff used this afternoon," Mr. Whiteside
told them, as he walked, recovering breath, toward the hangar door.

"Tommy is to keep his engine warm, idling, and to be ready, at the first
sign of escape, to take the air and overtake Jeff," he added.

"But maybe Sandy might get into trouble," urged Larry. "He'd fight to
stop Jeff, and that man is in a dangerous mood if he'd do what he has
done."

"It will do no harm to go over," agreed Mr. Whiteside, slamming the door
behind them. "It's shorter down along the water."

At a jog trot they went down the slope and at the wharf Dick gave a cry
of surprise.

"There's the motor boat--drifting just off the dock!"

"Then that woman--Mimi--came back to rejoin Jeff!" argued Larry, and
broke into a run. "Come on, fellows!"

Down the wharf path they ran, turning into the shell-powder path that
skirted the inlet on the far side of which the amphibian lay moored.

"Sandy will stop them," panted Dick, a little to the rear because of his
weight. Larry called, over his shoulder, that with two to give battle
to, Sandy might need them before they could arrive.

"There's somebody--on the lawn!" cried Dick, swinging off in that
direction. From behind a large tree emerged a figure. Larry and the
detective followed at a run. But the man who came quickly forward to
meet them gave all three a surprise.

"Tommy!" Larry recognized the pilot.

"Larsen, why aren't you by your airplane?" demanded Mr. Whiteside.

"I came over to report and get instructions, sir."

"Why, I gave----"

"Something new has come up, sir. I was waiting there by my ship a good
while back, and I heard another one cruising and spiraling, shooting the
field, I guess, because he came in and set down. My crate, just the way
you ordered, was down by the grove, not in plain sight in the middle of
the course. But Jeff set his ship down, left the engine running, and
went off. I stayed hid to see what would happen, but when he didn't come
back, I thought I'd better go and find you--and see if it meant anything
to you."

"Jeff's working with his wife, we think," volunteered Larry. "Anyhow a
woman slipped in and led us out of the hangar and started away in a
motor boat, and then she must have come back, because yonder's the
boat----"

"See anything of Mimi?" asked Mr. Whiteside eagerly.

"Haven't laid eyes on the lady."

"She must have met Jeff and gone with him. We're going to see."

"I have orders, at that," Mr. Whiteside told the pilot. "You go back and
get into the air and then cruise around--just in case Jeff does get
started."

"I will that."

"It would take him some time," argued Dick.

"He could start his motor and taxi while it warmed up, and be half
across the Sound before he took off if he wanted to, in that 'phib,'"
the pilot said. Turning, he called that he would get going, and returned
beyond their view beyond the trees.

Dick, Larry and Mr. Whiteside, listening for a call from Sandy, went
hurrying along. But no call from Sandy. He had decided that it would be
a wiser thing to hide than to risk doing battle with the pilot if he was
actually as bad as they suspected; with that in mind he had crawled in
through the opening from the back, into the fuselage of the amphibian.
There, fairly comfortable, he lay, full length, listening. The open top
allowed air to come because a strong, puffy breeze had gotten up,
driving great, black thunderclouds before it.

Sandy regretted his ruse presently, because he heard a boat and realized
that he could not see who occupied it: furthermore, while his position
would enable him to be hidden and to go along if Jeff took off, he would
be helpless in case of an accident to the craft.

When he decided to get out, it was almost too late--but not quite.

Jeff got his engine going by setting it on a compression point when he
had primed the cylinders and using his booster magneto to furnish the
hot sparks that gave it its first impulse.

Then, as soon as he heard Jeff drop the mooring rope and get in, Sandy
backed to a point where he could crawl to hands and knees, poked his
head up carefully, saw Jeff, adjusting his helmet as the engine roared,
and was able to climb over the seat back into the place behind the tank
before Jeff decided they were warmed up enough, got the craft on the
step and lifted it into the darkness, lit by intermittent flashes of
approaching lightning.

Sandy snapped his safety belt.

"Now, Mister Jeff," he remarked, safe behind the roar of their climb.
"Go anywhere you like--life preserver and all. I'll make the tracks
'sandy' for you if you want to stop!" He employed a railway expression,
whimsically applying it to the airplane instead.

Dick, Larry and the detective, hearing the roar of the engine, delayed
not a moment in their dash around the rest of the inlet shore.

They found that the amphibian was well out on the Sound, saw it lift.

It climbed in a northerly direction.

As they reached the vicinity of its starting point and called and
searched for Sandy, they heard the drone of another engine and saw the
red-and-green and the white flying lights of what must be Tommy's craft,
also going northerly in pursuit.

"There he goes!" Larry cried. "There must be some place in Connecticut
that Jeff and the woman with him know about--remember, Tommy's passenger
had him flying in that direction when the seaplane crashed, and the
hydroplane boat went that way--by gracious-golly-gravy! Do you suppose
it could have been the woman who ran off with that other life preserver,
while Jeff pretended he was too sick to take up a ship?"

"It could be," Dick replied. "I'm wondering more about Sandy."

"Let's go back to the house and make sure he didn't stop there to see
what Jeff had been doing before," Larry suggested. "He may have missed
going with Jeff. If the woman had been along he'd have had no place and
they would have left him here. But there isn't a trace."

"No signs of any struggle either," said the detective who had
investigated with his flash.

They returned to the house.

In the library, where Sandy had told Dick he had seen a glimmer of
light, they saw nothing especially unusual, unless they could attach
importance to an old photograph album, lying open on a corner settee
with several small snapshots removed and only the gummed stickers left
to show they had been there and what their size was.

"No Sandy," said Dick, worried. "Do you suppose they?----"

"I wonder if he saw two people coming and crawled into the fuselage,"
Larry said.

"He might have. I wish we could follow and see."

"I'm ready--and I think I'd be safe to fly, even if it does look like
storms. We could outfly Jeff, anyhow, catch up with him----"

He pointed to an open telephone book beside the instrument on the side
table.

"It's a Long Distance book, too--and its open at the E's!" Dick glanced
swiftly down the pages, "Evedall--Ever--Everdail!" he looked up with a
surprised face.

Instantly Larry caught up the receiver.

"Long Distance Operator, please," he spoke into the transmitter.

"Yes?"

"Long Distance?" He gave the number of the Everdail Maine estate,
secured from the open book. "Has that number been called recently? Can
you tell me?"

"Just a moment," came back to him.

The moment became two--three----

"Hello! It has! At ten o'clock. Thank you. Someone has been using our
house telephone, then. Goodbye!"

"It was called!" the detective showed a baffled face.

"And by Jeff!" Larry consulted his watch. "The time checks with the
report Sandy gave that Jeff was here. He called Mr. Everdail--why?"

"To tell him about the life preserver--and maybe to deliver it!"

"But Dick--he would never take it there if he means to----"

"I begin to think he doesn't mean to make away with it."

"But it had to be a pilot who did all the things we have evidence of,
Dick."

"Well--there's another pilot!"

"And he's flying after Jeff!" gasped the detective--leaping up he
started out. "Come, boys--Larry, will you try to fly us? I've been on
the wrong angle all along. Will you take us in Jeff's airplane, Larry?"

Larry would!

Jacketed from the supply Jeff kept for passengers, two of the Sky Patrol
and a discomfited detective rose in the air and joined the pursuit.

It was to have an unexpected outcome.




                             CHAPTER XXXIII
                       A BATTLE ABOVE THE CLOUDS


Hour after hour, into a North wind that cut down their forward mileage
somewhat, Larry held the airplane.

He flew low, in order to hold the coastline of the ocean, because he did
not dare try to navigate, inexperienced as he was, with no practice at
"blind flying" above the clouds.

Thunderstorms menaced, but always they were to the inland side, and
Larry did not have to pass through them, or climb above them and lose
his way.

Boston, easily recognized for its expanse and illumination, as well as
by the name-markers on certain roofs, painted there by air-minded
owners, finally came into view.

They circled until Larry located the large airport there.

Noting its white boundary lights, its red warnings, its windsock to give
him the direction of the air currents, he circled the field several
times, to be sure he would not foul any other ship, and to see if any
signal would be sent him.

Presently, after a commercial freight carrier had taken off, he got two
red lights, a signal to land, and as the field was wonderfully well
lighted, and he had learned to judge distance from the ground well,
Larry was repaid for his self-control and confidence and care by making
a perfect three-point landing.

Mr. Whiteside's explanations seemed to clear away need for formality.

While they were gassing up the airplane, he went to the administration
building and chatted with the field manager.

"The others are still ahead of us," he reported to Larry and Dick as
they munched a hurried meal and drank hot coffee, also securing
additional flying togs to supplement what they had.

"I wonder how much we've caught up on them," Larry said.

"Well, the amphibian stayed only a few minutes, and it wasn't gone five
minutes before the other one came in----"

"A two-place biplane?" asked Larry.

Mr. Whiteside nodded.

It remained only to get information, he stated, and then went up.

"Oh, dear," he finished. "I gave Tommy orders to ride down Jeff if he
had to, in order to stop him, and to get him arrested. I wish I could
stop him!"

"Who was in the first 'plane?" Dick asked.

"Sandy was there--they saw a boy, and Jeff got him some gloves; and they
seemed surprisingly friendly."

"That means that Jeff is innocent and has made friends with Sandy; but
where is the woman?"

Answering Dick, Mr. Whiteside explained.

"She was in the second airplane."

"With Tommy!" exclaimed Larry. "Then he's the one we want to catch, as
well as to save Jeff and Sandy from being driven down."

They wasted no time.

Friendly pilots, considering Larry such a boy aviator as Bobby Buck had
proved to be, gave him some instructions that were most valuable,
concerning night flying. The wind would be dead ahead, for most of his
trip toward Maine, and he could check his direction by that until he had
to veer to the West of North, when the wind, quartering, would drift him
off the course--but they gave him rough corrections, and advised him to
get above the clouds that were bearing down on Boston--local thunder
storms.

Once more the low-wing craft took the air, climbed to a good height,
Larry used his instructions, got the nose into the wind and drove ahead.

Slowly, as the distance behind them increased, their distance behind the
other two ships grew less. Minute by minute they cut their handicap.
Dick strained his eyes ahead, and to either side, watchful, eager.

He said almost nothing into the Gossport tube he had at his lips.

Larry knew his business: Dick wore the instructor's part of the outfit
only because it was the only helmet they could get at the start.

Under them black clouds, torn by vivid streaks of blue-white light,
reeled backward, their tops tumbling and tossing.

Above them the night sky shone serene, with the full moon, just nicked
by the curve of old Mother earth, riding higher and higher.

That was a glorious picture, had any one of them had the wish to enjoy
it. But they were intent on much more important sights than that of a
lovely sky.

"Flying lights ahead--" Dick spoke excitedly into the Gossport tube.

"Two sets--" he added.

Larry moved the throttle forward as far as it would go.

He peered ahead.

"Yes! There they are! Just a little below our level."

Closer and closer they approached. The two airplanes were vividly
visible in the bright light reflected upward also from the fleecy tops
of wind-tossed cloud.

"They're stunting--" Dick gasped.

"No--not stunting," Larry forgot his voice would not reach Dick.
"They're maneuvering."

It was clear to him. The amphibian, easily identified by its clumsy,
bulky looking trucks, with the pontoons slung to braces, was trying to
get away from a relentless biplane which sought to overtop it, to ride
down onto its tail, force it down.

Two war pilots fought it out above the clouds!

In the airplane with one sat a woman whose presence marked him for a
dangerous character, after the Everdail emeralds.

Behind the other pilot sat one of the Sky Patrol, at the mercy of a
devilishly minded adversary, and he was as helpless to save himself as
Larry and Dick were to aid him!

Larry, thinking of that, but hoping against hope that for all his lack
of experience he might see some opportunity to stop the other man,
banked moderately and began to circle.

They watched, breathlessly.

The amphibian, under Jeff's adroit piloting, side-slipped from under its
danger.

"Good!" panted Dick, unaware that his voice carried through the tube to
Larry, who nodded.

"He's trying to climb higher," added Dick.

"But he can't outclimb the biplane, unless--"

Larry breathed a prayer of thanksgiving. Sandy was all right, saved for
the time being from danger of being driven down.

A bright idea struck Dick.

"Listen, Larry," he said into his tube. "If we could fly level with the
amphibian, I could use my flashlight to flick a message to Sandy, and
tell him to lower the life preserver while we fly directly under his
craft, until we catch it and pull it into our ship."

Larry nodded.

With his flashlight flicking the dots and dashes of the Morse code to
Sandy, Dick spelt out a message explaining his idea. Twice he flashed
the message, got an O. K. from Sandy, and told Larry.

There were some preparations on the other skycraft, then Larry dropped
the nose of his plane and went down a few feet. The amphibian flew over
them, high enough so its hanging pontoons would not scrape their craft,
and as the cockpits were low, it could drop fairly close.

Sandy leaned out, a doughnut of white came shaking and swinging at the
end of a rope. Dick braced himself, safety belt snapped tight, arms
extended upward. Larry held his ship at flying speed and level. Once an
air shift dipped the amphibian dangerously low, but Larry saw it coming
and dived ten feet, then leveled again. Once more they tried to jockey
into position.

Dick saw the doughnut swing toward him, threw his head back to avoid the
blow, but it struck his chest. With a grunt, his arms closed and he
clung. Sandy, feeling the tug of the rope, let go.

Dick dragged in the rope to prevent it from flying back into the
empennage, fouling the tail assembly--and they had the preserver.

Then Dick shouted a warning. Larry dived. Tommy was coming at them.




                             CHAPTER XXXIV
                         THE EMERALDS ARE FOUND


Larry sent his craft into a sharp dive. Tommy, trying to prevent the
maneuver, came straight toward the spot they had occupied, but missed.

Now the clouds hid them. By use of his instruments he could keep on a
level keel, Larry knew, and with the engine throttled off, they could
not be traced by its roar.

Presently they sailed out into a clear area and Larry sighed thankfully.
He watched for a landing field beside a lake shaped like a half-moon.
That would tell him he could set down on the landing spot the
millionaire had built before going West.

Then he saw it. They began to drop swiftly, coming ever closer to the
field. And then they set down, safe and unmolested.

Before the chums were clear of the runway, Tommy set down his ship,
tumbled out and let the woman with him--the yacht stewardess--get out as
best she could. "What do you mean, double-crossing me?" screamed Tommy
at detective Whiteside. "Why have you tried to get the emeralds after
you promised me half of them?"

"The man has gone crazy," said Whiteside.

"They are all in it together, Mr. Everdail," Tommy shouted, turning
toward the millionaire.

"What are you doing with that stewardess?" demanded Larry. "She joined
you on the lawn when you came from behind the trees."

"Be still," cried Everdail. "We can thresh it out later. Right now let's
get those emeralds."

Larry produced a knife, and Mr. Everdail slashed the life preserver to
ribbons.

There was a gasp. The life preserver was empty.

Then everyone began to talk at once, as accusations flew back and forth.

"Boss, I want you to take a look at this-here stuff I brought from your
house," said Jeff, drawing a parcel from his pocket.

"Good night!" Sandy was amazed. "Jeff, that's the family history of the
Everdails, that I saw when I visited the farm boys and found out you and
Mimi were married."

"That-there is it," agreed Jeff, taking several tintypes from an
envelope. "Boss, read that history of your family and see if it makes it
plain why anybody wanted to destroy your gems."

In the light of a flare, Mr. Everdail perused the pages.

"As I live and breathe!" he exclaimed.

"Yeah," grinned Jeff. "Thanks to Sandy for leaving the book there, and
thanks to--a certain relative of yours for leaving a marker at the right
place. Now, take a look at these pictures out of your family album. They
are pictures of the man who originally got the emeralds in India, and
his son. Whose face that you know is close to being the same?"

With the scream of a madman, Mr. Whiteside leaped to the side of the
group.

"Yes!" he babbled. "Yes! I am the son of the branch of your family that
originally had the emeralds. My grandfather, for spite against my
father, willed them to your family. Those emeralds ought to be mine--and
my sister's"--here he gestured toward the stewardess.

"Yes!" cried Whiteside Everdail--as they now learned his name was--"I
grew up hating Atley Everdail's family. I enlisted in the flying corps,
got into his esquadrille, made a buddy of him, won his trust!

"I worked into his confidence, and watched every chance to get the
emeralds. My time came when his wife went to London. I had my
sister--stewardess, she was--already on the yacht.

"I beat the yacht to London. With her help--forced by threats--I got
into the hotel and destroyed the gems--I thought. But on the way back to
my room I saw Captain Parks, and began to suspect. I compelled my sister
to admit the truth. The real gems were safe.

"I came to America, made the hinged door to the hangar, rewired the
switches to get light by day to prepare the amphibian.

"I hired Tommy Larsen--he didn't know the truth at first. Then I saw
Jeff was getting suspicious, changed my plans and got a seaplane. I even
went with Atley to see my own plan carried out," he screeched.

"But everything went wrong. The life preserver hid the gems. I knew
that, and made my sister run off with the wrong preserver, that I took
from Jeff's airplane. I thought the right preserver was in the seaplane,
but Tommy was 'wise,' and refused to do any more than watch me, and when
my sister came to get the emeralds, he tried to prevent me from getting
away with it. You can piece out the rest. You'll never punish me! You'll
never--take me alive!"

Eluding them, he dashed straight down to where Jeff's amphibian, its
prop still turning, stood fifty feet from the end of the runway.
Tumbling into the cockpit, he threw the throttle wide. Down the few feet
the amphibian roared, gathering speed.

The rend and crash, the tear of metal, wood and fabric as the craft
dashed against a tree, was followed by a shrill scream from the
stewardess.

In one thing the fanatic prophesied truly. They did not take him alive.
But still they did not know where the emeralds were!

Next morning the Sky Patrol, the millionaire and others took the train
from camp to the harbor.

But although Mimi showed which she thought was the right belt--although
they ripped apart every life preserver on the yacht--no jewels appeared.

"I've thought of every possible hiding place," Sandy told his chums,
"and the only thing I can see to do is--if they were in a life preserver
at all--what do you say to trying this--"

He outlined a plan. So promising did it seem that both Dick and Larry
agreed to it.

That night an alarm of fire, red glow, yellow and red flames, and
suffocating smoke, terrified everyone.

Tracing the smoke to the galley, Mr. Everdail was astounded to find Dick
and Larry struggling with a man in pajamas--he had rushed in, had
seen--too late--the red flares, colored fire powder and smoke pots that
burned in buckets, and had been unable to disguise the fact that he had
dragged two ice trays from the refrigerator. They contained--green ice!

"As I live and breathe!" cried Mr. Everdail, inspecting a tray.

Quickly overpowered, their captive confessed. The chef had taken the
emeralds from the life preserver and frozen them in ice cubes of a deep
emerald-green dye. These he easily preserved during the short times the
trays were needed for other cubes, by putting them into one of the deep
vegetable trays used in the refrigerating system.

That was how the chums were misled the night of Sandy's birthday party.
The trays had been emptied when they looked, and because the trays had
just been used for tinted ice and were logically empty, they were
fooled.

"But I was a coward--my conscience bothered me," the chef admitted. "I
wanted to return 'em, I wanted to take 'em. So, now--I'm glad I only
kept them for you!"

"Well, Sky Patrol," said Jeff as the boys pocketed their reward checks,
"the sole of that-there right foot of mine itches. That means I'm to go
into a new business and prosper--with the help of my Sky Patrol and
Ground Crew. How about it?"

"Drop a signal flare," urged Sandy. "We'll come a-flying!"

And that was settled!




                          Transcriber's Notes


--Copyright notice provided as in the original--this e-text is public
  domain in the country of publication.

--Silently corrected palpable typos; left non-standard spellings and
  dialect unchanged.

--In the text versions, delimited italics text in _underscores_ (the
  HTML version reproduces the font form of the printed book.)







End of Project Gutenberg's The Haunted Hangar, by Ardon Van Buren Powell