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THE SECRET WIRELESS

or

The Spy Hunt of the Camp Brady Patrol

by

LEWIS E. THEISS

Illustrated by Frank T. Merrill







[Frontispiece: no caption]



W. A. Wilde Company
Boston ------ Chicago
Copyrighted, 1918,
by W. A. Wilde Company
All rights reserved

THE SECRET WIRELESS




To

WALTER K. RHODES, A.M., E.E.,

  PROFESSOR OF ELECTRO-TECHNICS
  IN BUCKNELL UNIVERSITY,

  TO WHOSE KINDLY HELPFULNESS IS DUE
  WHATEVER OF TECHNICAL MERIT THERE
  MAY BE IN THIS AND COMPANION STORIES
  OF THE "WIRELESS,"

This Book is Dedicated




Contents


     I.  WHAT CAME OF HENRY'S IDEA
    II.  HENRY OVERCOMES AN OBSTACLE
   III.  THE WIRELESS PATROL PREPARES FOR ACTION
    IV.  THE SCENE OF ACTION
     V.  THE MESSAGE IN CIPHER
    VI.  A NEW DANGER POINT
   VII.  CONFUSION WORSE CONFOUNDED
  VIII.  WHERE MONEY TALKED
    IX.  A FRESH START
     X.  THE PURSUIT IN THE DARK
    XI.  AN UNSUCCESSFUL SEARCH
   XII.  ANOTHER OBSTACLE
  XIII.  WHAT HENRY DISCOVERED
   XIV.  THE RIDDLE SOLVED
    XV.  ANOTHER MYSTERY UNRAVELED
   XVI.  AN UNEXPECTED MESSAGE
  XVII.  A CHANGE IN CIPHERS
 XVIII.  TOO LATE
   XIX.  THE ENEMY ESCAPES
    XX.  A CLUE FROM THE AIR
   XXI.  THE CAPTURE OF THE SPIES
  XXII.  A TASK ACCOMPLISHED




ILLUSTRATIONS


   Frontispiece

   Up came a sliding inner tube




The Secret Wireless


CHAPTER I

WHAT CAME OF HENRY'S IDEA

Henry Harper was sitting in the doorway of the workshop in his father's
back yard, where the Camp Brady Wireless Club made their headquarters.
He was reading the morning newspaper.  Suddenly he sprang to his feet.
His face grew black.  His free hand clenched.

"That's terrible!" he exclaimed.  "Terrible!"

He walked across the shop, spread the newspaper on the bench and began
to read aloud the big head-lines that had so aroused him.

  LEAK IN NAVY DEPARTMENT

  _Germans Knew of Departure of Transport Fleet_
  _First Contingent of Pershing's Men Attacked, by Waiting
    Submarines_

"It's terrible, terrible!" repeated Henry.  "Their spies are
everywhere.  They stop at nothing.  Who could have been villain enough
to give them the information?  It is terrible!"

In his agitation Henry began to pace up and down the floor of the shop.
His face grew blacker and blacker as he brooded over the story of
treachery.  Though Henry was not yet eighteen, he was affected far more
deeply by the story than most boys of his age would have been.  For
when the Camp Brady Wireless Club, of which Henry was president, had
been practising the previous summer, Henry had been called upon to
replace one of Uncle Sam's radio men who was suddenly stricken with
appendicitis, and Henry had taken the operator's oath of fidelity to
his government.  So to him treachery appeared doubly black.

For some moments he paced up and down the shop.  Suddenly he stopped
short.  A new idea had come to him.

"How did they get the news to Germany?" he asked aloud.  "Both the
cables and the mails are censored--and besides the mails would be too
slow.  It must have been the wireless.  Can there be traitors in the
wireless service, too?"

Henry was silent a moment, his brow wrinkled in thought.  "Never!" he
cried suddenly.  "Uncle Sam's radio men are true blue.  It's a secret
wireless!  A secret wireless!  The Germans have got a hidden station
somewhere."

The black look left his face.  The scowl was replaced by a gleam of
joy.  "That means a job for us!" he cried.  "The wireless patrol can
help find that station, just as we found the German dynamiters at Elk
City."

For when the wireless patrol had been at Camp Brady only a few weeks
previously, acting as official operators for the commander of the
troops guarding that section of the country, Roy Mercer had picked an
innocent-looking message out of the air one night and by accident had
found a code message in it revealing a German plot to dynamite a great
dam and destroy a munition city; and later the wireless patrol had run
down the dynamiters themselves in the very nick of time, after the
state police had failed to find them, and had saved the city.

With Henry, to think was to act.  "I'll write Captain Hardy at once,"
he said to himself.

Captain Hardy was a young physician who had been leader of the club of
boys that had camped on his father's farm near old Fort Brady, and that
had subsequently become the Camp Brady Wireless Club.  But Captain
Hardy was no longer leader of the club.  He had offered his services to
his country, and was now Captain Hardy of the Medical Officers' Reserve
Corps.  It was his standing and his friendship with the Chief of the
Radio Service that had made it possible to secure permission for the
Camp Brady boys to act as radio men for the state troops the preceding
summer, although the government had forbidden amateurs to send wireless
messages.  And Henry, believing that his idolized leader could
accomplish anything, now cleared a space at his desk in a corner of the
shop, and wrote him a long letter, setting forth all that was in his
heart.

The promptness with which the answer came should have warned Henry that
the reply was not the one he hoped for.  But his faith in his leader
was so great that he never doubted for a moment that if Captain Hardy
favored the proposal, he could effect its accomplishment.  With a shout
of joy, Henry seized the letter from the hand of the postman and ran to
his favorite haunt, the workshop, to read it.  As he did so, the smile
faded from his face and a look of utter despair succeeded it, for this
was what he read:


"MY DEAR HENRY:

"It was a very great pleasure to receive your letter, with the little
items of information about the members of the club, and your plan to be
helpful in the present emergency.  I know exactly how you feel.  Every
true American is filled with similar loathing for the treacherous
enemies that infest our land, and with the same ardent desire to hunt
them down and bring them to justice.  You may be very sure that our
secret service men are hard on the trail of many of them.  Yet the very
story of treachery that has so stirred your indignation shows that the
secret service men cannot cope with them.  But the fault is not with
the secret service.  It lies with Congress, which has persistently
refused to appropriate sufficient money to make the service adequate.
As far as it goes, it is the peer of any secret service.  Of course
help is needed, but I very much fear it is not the sort of assistance
that the Camp Brady boys are prepared to give.

"You see, Henry, there are two possibilities.  Either there is a leak
in the navy department itself, as your story says, or else the sailing
of the troops was observed at the port of embarkation and their
destination guessed at.  There is nothing you could do in the way of
apprehending a spy in Washington, and I doubt if you could be of much
assistance in detecting German agents in our ports.  Of course I know
how skilful the boys are with their wireless, especially you and Willie
Brown, and I know what close observers Roy Mercer and Lew Heinsling
are.  And I realize, too, that in running down the dynamiters at the
Elk City reservoir after both the Pennsylvania troops and the state
police had failed, you proved that the wireless patrol was a mighty
efficient organization.  But that campaign was accomplished in the
mountains and forests where your training in scouting and woodcraft has
made you at home.  Conditions in a great seaport would be so strange
and confusing to all of you that I fear you would be more of a
hindrance than a help.

"I am sorry about it, for I know how keenly you feel and how eager you
are to help your country.  The best way you can do that is to continue
in school, learning all you can and making yourselves more and more
efficient as wireless operators.  In a very short time, I suspect,
Uncle Sam will be in pressing need of good radio men.  Then, although
you are still young, your chance will come; for your ability is already
known to the Chief of the Radio Service through your capture of the
dynamiters last summer.

"As you know, our camp is just outside of Washington.  I happen to be
going into the city to-morrow.  Of course, I shall take occasion to lay
your suggestion before the Chief.  But do not build any hopes on that
statement.  I have no idea anything will come of it.  But it may help
the Chief to bear you in mind later on.  I am sorry to dash your hopes,
but I cannot do otherwise than to tell you the truth.  Of course if
anything should come of it, I will let you know promptly.  Remember me
to all the other boys.

"Sincerely yours,

  "JAMES HARDY."


Henry's face became longer and longer as he read.  When he had finished
the letter there was more than a suspicion of moisture in his eyes.

"Oh!" he cried, "if only I could be with Captain Hardy when he sees the
Chief of the Radio Service, I'd _make_ the Chief understand that we can
help.  We could be just as useful to the radio men as the Baker Street
Irregulars were to Sherlock Holmes.  Oh!  I just wish I could be with
him.  I wonder when he will see the Chief."

Henry picked up the envelope and examined the postmark.  "This was
mailed yesterday morning," he muttered, "and Captain Hardy said he was
going to Washington to-morrow.  That's to-day.  Maybe he's with him
this afternoon.  Maybe he went this morning.  I'm sure he knows by this
time what the result is.  Oh!  I wish I were with him.  I'd just _make_
that Radio Chief take us."

As he spoke a telegraph messenger entered the yard.  He caught sight of
Henry in the workshop door.  "Hey!" he called.  "Does Henry Harper live
here?  Got a message for him."

Henry was almost too much amazed to answer.  He had never received a
telegram in his life before.

"Hey!" called the messenger again.  "Are you asleep?"

"No," was the answer, "and I'm Henry Harper."

"Then why didn't you say so?"

Henry ran forward and seized the yellow envelope.  "Where's it from?"
he asked.

"Washington," said the messenger.

"Washington!" repeated Henry.  "Washington!  Then we're to go."

"If you'll sign here," said the messenger, "I'll go.  I can't stand
here all day.  Nothin' to pay."

Henry signed the messenger's book, then tore open the envelope and took
out the following telegram: "Want you, Roy, Lew, and Willie to meet me
Pennsylvania Station New York City Friday two P. M. for work suggested
in your letter."




CHAPTER II

HENRY OVERCOMES AN OBSTACLE

Could the messenger boy have seen Henry after the latter had read the
telegram, he would soon have changed his mind as to Henry's sleepiness.
For a very brief space--just long enough to reread the message once or
twice--Henry stood like one dazed, as motionless as a statue, and as
silent as a sign-post.  Then he gave a loud whoop and began to dance
around the little shop.  For a boy who was ordinarily so sober as
Henry, such conduct was scandalously riotous.  He skipped about the
tiny wireless room, waving his hat in his hand, cheering for the Camp
Brady Wireless Patrol, and making loud declarations as to what that
organization would do to the enemies of the country.

Ordinarily Henry would have restrained himself.  Not even the news that
the Camp Brady Patrol had been selected to perform the wireless service
at the guard headquarters the preceding summer had excited Henry as did
this message from his captain.  But that was scarcely to be wondered
at.  The work for the commander of the Pennsylvania guards had promised
nothing but the sending of uninteresting and wordy despatches, though
to be sure it had turned out quite differently before it was ended.
But the task now in view promised excitement from the start.  It
breathed adventure, romance.  To hunt spies--to trace traitors--to turn
the searchlight on hidden crimes and dark deeds--to outwit clever
men--to take a man's part in a man's world--to do deeds of daring and
bravery--and above all to serve his country and save his fellows--these
were the things that came into his mind as the probable results of the
precious communication he held in his hand.

Forgotten were the tedious hours of monotony that his sober senses
would have told him must make up the greater part of any such labor as
that he was now about to embark upon.  Forgotten were the dull, deadly
dull and uninteresting days that his experience should have told him
lay before him.  In his enthusiasm Henry saw only the bright spots.
The mental vision he looked upon glowed with rosy light.  And Henry
gave himself up utterly to enjoyment of the prospect.

So he danced and shouted and waved his hat, and cheered for the Camp
Brady Patrol, until in his excitement he danced too close to the side
of the tiny shop.  His wildly waving hat came into contact with sundry
tools and kettles and other metal implements hung up on nails to be out
of the way.  Down came saws and pails and a sprinkling can, and the
hoe, and a dozen other articles in a noisy crash.  It sounded as though
a cyclone had suddenly descended upon the little shop, or a
42-centimeter shell had burst within.  The exultant chant of the lone
occupant of the building suddenly ceased.  But its place was instantly
taken by another voice as Henry's mother suddenly appeared on the back
porch of the house, looking anxiously toward the workshop.

"Henry!  Henry!" came her anxious call.

"Yes, mother," replied Henry, disentangling himself from the wreckage,
and thrusting his head out of the shop door.  "What is it?"

"Whatever are you doing?" demanded Mrs. Harper.  "I thought the shop
had tumbled in."

"It's only some things I knocked down," laughed Henry.  Then his
enthusiasm bubbled over again.  "Just think, mother," he cried.  "We're
going!  We're going!  Captain Hardy has sent for us!"

Mrs. Harper looked at her son anxiously.  His words meant absolutely
nothing to her, for Henry had not told any one of his letter to his
captain.  Suddenly she feared that perhaps something had fallen on
Henry's head and momentarily unbalanced him.

"Going?" she said.  "Where?  What are you talking about?"

"We're going to New York City to help catch German spies," cried Henry,
beginning to dance about again in his excitement.  "Isn't it bully!
And we'll catch 'em, too, just as we did the dynamiters."

"I guess you're going crazy," said his mother.  Then as Henry continued
his demonstration, his mother said sharply, "You stop right there,
Henry Harper, and tell me what all this nonsense means about German
spies and New York and Captain Hardy.  You know very well that Captain
Hardy is in Washington with the army."

Henry at once calmed down and took a grip on himself.  "Yes, mother,"
he said.  "Captain Hardy was in Washington, but he is going to New
York----"

"How do you know?" interrupted Mrs. Harper impatiently.

"He just telegraphed me----"

"Telegraphed you!" said the incredulous Mrs. Harper.  "What would
Captain Hardy be telegraphing to a youngster like you for, I'd like to
know."

"In answer to my letter----" began Henry, but again his mother cut him
short.

"Your letter?" she said.  "What letter?  I didn't know that you had
written him a letter."

"You see, mother," said Henry patiently, "when I read in the newspapers
the other day that the Germans had found out about the sailing of
Pershing's men, and had sent submarines to lay in wait for them out in
the ocean, the idea came to me that perhaps the wireless patrol could
help to discover----"

"Henry Harper, I hope you never had the impudence to suggest that you
youngsters could----"

"I did, mother.  But I don't think it was impudence.  I wrote to Dr.
Hardy and asked if the wireless patrol couldn't help catch the spies
who are sending news to Germany."

"Well of all things!" ejaculated Mrs. Harper.  "What will you infants
do next?  Offer to relieve the President of his job?"

"Well, we did catch the dynamiters at the Elk City reservoir,"
protested Henry defensively.  "And we did it after the state police and
the national guards had failed.  I don't see why we can't help catch
German spies in New York just as well as in Pennsylvania."

"Humph!" said Mrs. Harper.  "It's a lot of help you youngsters would be
in catching real spies.  You just happened to stumble on these
dynamiters and now you think you can do thing.  But that's the way with
boys.  They're all alike."

"But, mother," protested Henry, "boys can be useful in lots of ways.
And just because they are boys nobody thinks of suspecting them."

"There's one place where a certain boy I know could be of a lot of use
and never be suspected," agreed Mrs. Harper.  "And that's at that
woodpile back of the shed."

"Please don't interrupt me, mother," said Henry.  "You asked me to tell
you about our trip to New York."

"About your dream of a trip to New York," corrected Mrs. Harper.  "You
don't for one minute think you are really going to New York, do you?"

"Indeed we are," replied Henry.  "And this is how it came about.  When
I read of the leak in the navy's secrets and the attempts of the
Germans to torpedo our transports, I wrote to Captain Hardy about it.
I told him we could be just as useful catching German spies in New York
as we were in Pennsylvania.  He answered and said he didn't think we
could be of any use, but----"

"Showed his sense," interrupted Mrs. Harper.

"But he said," continued Henry, paying no attention to the
interruption, "that he would mention the matter to the Chief of the
Radio Service and let me know if anything came of it.  And something
has come of it, mother.  Just think!  We're to go.  Here's the telegram
itself."

Mrs. Harper took the yellow paper that Henry held out to her and read
it slowly and carefully.  "Well, I never!" she said at last.  "I never
did!  But I don't know whether to let you go or not.  Why, you'd be
lost inside of ten minutes in New York, and instead of being a help to
the police, you'd keep them busy hunting for you.  I don't know about
this.  Wait till your father gets home and we'll talk it over."

"But, mother," protested Henry, "I can't wait.  And we've _got_ to go.
The Chief of the Radio Service has asked for our help.  That means the
government wants us.  If it wants us, it must need us.  And we've just
got to go."

"Humph!" said Mrs. Harper.

"And besides," added Henry, reading the signs in his mother's face,
"Dr. Hardy is to be in New York with us, so we can't get into trouble."

"Well, that alters the case," said Mrs. Harper.  "With Dr. Hardy to
look after you, I reckon you _can't_ go very far astray."

"Then we can go, mother?"

"I suppose so.  I know your father thinks every one of us should do
everything he possibly can to help win this war.  But it gets me to
know what you youngsters can do that will be of any use.  Still, I
guess the government wouldn't have sent for you if it didn't want you,
and I won't stand in the road of the government."

"Hurrah!" shouted Henry.  "Then I'm off to tell the others."  And he
darted out of the yard and was away like an arrow.




CHAPTER III

THE WIRELESS PATROL PREPARES FOR ACTION

At top speed Henry tore down the street.

Half a block from his home he passed a schoolmate.

"Hey!  What's your hurry?" the latter called out, as Henry dashed past
him.

"Wireless patrol ordered out!" Henry shouted over his shoulder, as he
darted on down the street.

"Wait a minute!" called the other lad.

"Can't," cried Henry.  "Got to get the patrol together to go on a spy
hunt."

At the words "spy hunt" the other boy leaped forward and ran after
Henry at top speed.  "What's up?" he asked enviously, as he overtook
Henry and raced along beside him.  For the lad did not belong to the
wireless patrol.

"Ordered to New York by the government," panted Henry, "to hunt for
German spies."

The announcement had all the effect Henry intended it to have.  For a
full half minute his companion said never a word, but ran mutely beside
him, his eyes fastened incredulously on Henry.  Then, "Gee whiz!" he
said.  "You're not really goin' to New York!"

"Sure thing," panted Henry.  "Just got a telegram from Washington."

That was too much for Henry's companion.  "Gee whiz!" he said again.
"I wish I belonged to the wireless patrol."

Henry looked at him sympathetically, half sorry that he had said what
he had.  "Maybe you will some day," he replied.  "Good-bye."

They had reached the home of wee Willie Brown.  Henry stopped abruptly
and turned in at the open gate.  He mounted the steps and rang the
bell.  Mrs. Brown opened the door.

"Is Willie--at home--Mrs. Brown?" he asked, all out of breath.

"Yes, Henry," replied Mrs. Brown.  "You'll find him up in his room."

"Is he busy?"

"Oh!  He's tinkering with his wireless, as usual," said Mrs. Brown.
"But he's always glad to see you, Henry."

"He will be this time, I'm sure," said Henry.  "The wireless patrol is
ordered out on a spy hunt."

"What!  Not again?" queried Mrs. Brown, in astonishment.  "Where are
you going this time?"

"To New York," rejoined Henry, and his voice plainly showed his
exultation.

"Tell me more about it."  Mrs. Brown was at once all seriousness.

Henry turned away from the stair door and explained the situation to
Mrs. Brown, who was very sober.  But when Henry said that Dr. Hardy had
asked the boys to come and that he would himself be with them in New
York, the serious look vanished from Mrs. Brown's face.  "That's all
right, then," she said.  "If Dr. Hardy wants you and is to be there to
look after you, it is all right.  I am glad Willie has the opportunity
to go.  He has never been in a really big city."

Henry went on up to Willie's room and broke the news to him.  And the
sounds that came down to Mrs. Brown made her laugh heartily.  But it
was a laugh of sympathy.  She remembered that she had once been young
herself.  Presently the racket up-stairs subsided.  Then came the
clatter of noisy and eager feet on the stairs.  And a moment later
Henry and Willie skipped out of the door, tore through the gate, and
went racing up the street toward Roy Mercer's house.

But Roy was not at home.  He was, as Henry had suspected he would be,
at work in the garage where he had been employed during the school
vacation.  But Henry thought it would be well to secure permission from
Mrs. Mercer for Roy to take the trip to New York, for she was inclined
to be rather strict with Roy.

"Captain Hardy has just sent me a request for four of the boys of the
wireless patrol to come to New York," said Henry, diplomatically, "and
Roy is one of the four he wants.  We came to see if he may go."

Mrs. Mercer looked at Henry keenly.  "What are you going to do in New
York," she demanded, "and who's to pay the bills?"

"I don't know exactly what we're to do," said Henry, "but we're to help
the wireless service.  I think they want us to listen in and pick up
low-length messages that the high-powered government stations don't
get.  The government will pay our expenses."

"Humph!" said Mrs. Mercer.  Then she was silent a moment in thought.
"When does Dr. Hardy want you to go?"

"He wants us to meet him in New York at two o'clock Friday afternoon.
That means we should have to leave here on the early morning train
Friday."

"I don't know about this," said Mrs. Mercer.  "All play and no work is
just as bad for a boy as no play and all work.  And Roy has done
nothing but play all summer.  He has been at that camp of yours ever
since school closed.  And besides, he is earning three dollars a week
working at the garage."

Henry had feared that Mrs. Mercer would object to Roy's going.  Roy's
father had been sick and unable to work for some weeks, and Henry knew
that the three dollars Roy earned each week were badly needed in the
Mercer home.

"I think that the government will pay Roy more than he earns now,"
explained Henry.  "And I hope that you will let him go because Captain
Hardy wants only certain boys and Roy is one of them.  He is very
necessary to the success of our work."

"I'll see what Roy's father says," was the reply, and Mrs. Mercer
vanished within the house.

Meantime Henry and Willie stood on the porch hardly daring to speak to
one another, so fearful were they that Roy might not be allowed to go.
When Mrs. Mercer suddenly appeared again and announced briefly that Roy
could go, they thanked her, and as soon as they could get around a
corner, they gave vent to their feelings in a loud whoop.

Lew Heinsling was picked up a few minutes later, with no objection on
the part of his parents, and the three boys raced to the garage, where
they imparted the news to Roy.

School, which normally should already have been in session, had been
kept from opening by an epidemic of measles; and no one knew when it
would convene.  But there was no apparent chance of an early opening,
for the epidemic was then at its worst.  There was no obstacle now in
the way of the four boys.  Roy got his employer's permission to leave
the garage for an hour, and the four boys hurried to the wireless
patrol headquarters in Henry's shop, to discuss the adventure that lay
before them.

That night the entire patrol assembled in the little workshop and those
who were not to go enviously discussed the coming adventure with the
four who had been summoned to duty.  For no one in the patrol doubted
that the expedition would end in adventure and excitement, to say
nothing of the delights of a trip to the nation's metropolis.  Their
common experience in running down the dynamiters at the Elk City
reservoir gave these boys the certainty that both adventure and danger
lay ahead of their four lucky fellows.  But could they have known how
truly thrilling and adventurous were the days ahead of their
companions; could they have foreseen all the strange and exciting
situations that would confront their fellows; could they have guessed
the part their comrades of the wireless patrol were about to play in
wiping out this hidden menace to our troops on the ocean, they would
have been envious indeed.

But they could not know these things.  And they recognized the fact
that Captain Hardy had asked for these four because of their superior
attainments, because they were best fitted to do the work in hand.  So
the stay-at-homes loyally crushed down their feeling of envy and united
in a hearty send-off for their fellows.  Every member of the patrol was
at the railroad station Friday morning to bid good-bye to their four
comrades who were to play no inconspicuous part in the stirring days to
come, and who were to make known to the country at large the name of
the Camp Brady Wireless Patrol.




CHAPTER IV

THE SCENE OF ACTION

As the conductor shouted "All aboard!" the little group of boys on the
station platform suddenly parted, and the four who had stood in the
centre of the ring, vigorously shaking hands, now moved hastily toward
the train and scrambled up the steps.  The conductor waved his signal
to the engine-driver and swung aboard.  The locomotive bell began to
ring, there was a hissing of steam, and a puffing of the great
locomotive, and the train slid gently forward.  On the car platform
stood the four departing members of the wireless patrol, waving fond
farewells to their less fortunate members.  Then they turned and
entered the coach, with the cheers of their comrades ringing in their
ears, their hearts beating with high determination to give all that
they had of strength and skill and courage and patience to the grim
task that lay ahead of them.

In no time Central City was lost from sight.  The familiar fields and
woods vanished.  The country grew strange.  Soon they were passing
through a region entirely unknown to them.  But so busy was each boy
with his thoughts that he hardly noticed what at other times would have
held his closest attention; for the pictures in each mind were just as
unfamiliar as the landscape through which they were speeding.

"What was to be the nature of their work?" each boy was asking himself.
"Would they sit and listen in, as they had done at Camp Brady, or would
they be set to roving about, trying to pick out suspicious characters,
or detect suspicious acts?  And what would New York be like?  What was
there about this great, roaring city of men that was so attractive,
that drew such multitudes to it, that grew with such uncanny swiftness?
What was New York like, anyway?"

And almost before they knew it, the train rolled into a tunnel, dived
under a great river, and emerged again in a huge yard far below the
level of the streets, that was filled with many tracks and closed in
with enormous walls of cement.  Then the train ran into a great shed
and came to rest.  The boys left the coach, mounted a long flight of
iron steps and found themselves in the city of their dreams--New York.

And there, at the gateway, was their beloved captain.  They swarmed
about him and grasped his hand.  Then Captain Hardy led them to a
corner of the waiting-room that offered a little privacy, and there
they sat down in a group, close to one another, to talk over the
business that had brought them again together.

"As I wrote you in my letter, Henry," said Captain Hardy, "I was not at
all hopeful that your plan would meet with official encouragement.  But
I had promised you that I would mention it to the Chief of the Radio
Service and I did so.  It didn't take him a minute to decide on it.  To
my surprise he said he wanted you.  'I haven't a bit of doubt,' said
he, 'that the country's full of secret German wireless outfits.  They
are probably of small sending power and operate in unusual wave
lengths.  It is almost impossible for our regular service to detect
them.  In fact I don't know how we are ever going to locate them unless
we organize the amateurs all over the country so that they can listen
in and catch practically everything that goes through the air.  We are
not able to do that yet, but I shall be very glad to have the help of
your boys.  I've been mighty interested in the way they handled that
affair at Elk City.  They are experienced and have good sense.  They
should be very useful to Uncle Sam.'"  Dr. Hardy paused and smiled.
"You see," he went on, "the Chief has kept pretty close watch of you
boys.  He knows all about the affair at Elk City."  And Captain Hardy
smiled affectionately at his charges.

"What are the Radio Chief's instructions?" asked Roy.  "What are we to
do?"

"The Radio Service," replied Captain Hardy, "has no agencies for making
arrests and detecting crime.  So we shall work under the direction of
the secret service and in coöperation with the police.  And our first
duty is to make ourselves known to both."

"If the Chief of the Radio Service wanted the wireless patrol," said
Roy, "why did you telegraph for just the four of us?  And why are we in
New York instead of Washington?"

"You couldn't be of any use in Washington," said Captain Hardy, "but
you may be of a great deal of service here.  You see New York is a
difficult place to guard.  This is our principal port.  It is so vast
that it is next to impossible to watch all of it, and there are
hundreds of thousands of Germans or people of German descent living
here.  The Radio Chief needs sharp eyes and ears as well as trained
fingers just now, and he knows that you boys combine these
qualifications.  He suggested that I send for four of you and see what
you could accomplish.  I chose you four because you have shown the
greatest ability along the lines necessary."

A flush of pleasure glowed in each of the faces before him.  For a
moment Willie Brown forgot where he was, forgot the crowd and the great
station and the strange sights and sounds about him, forgot even why he
was in New York, while his mind went back to that first summer at Camp
Brady, when he had been the most backward, self-distrustful, helpless
lad in camp.  Now he was chosen to serve his government, to do work of
the greatest importance for his country; and he had been selected
because of his ability.  No wonder Willie blessed the day he first saw
Camp Brady.  No wonder his eyes were wet with a grateful mist as he
looked affectionately at his captain, who had made him what he was.

But Willie had little time for revery.  Roy was speaking again, asking
another of those sharp questions that showed very well why he should
have been chosen as a spy hunter, or for anything else that required
keenness of mind.

"What about yourself?" Roy was saying.  "Do you have to go back to your
medical duties?  We can work ever so much better with you to lead us
than we could with a stranger."

Roy alone had grasped the possibility that Captain Hardy might not be
able to remain with them.  Now every eye was fixed anxiously on Captain
Hardy's face.

"No," he said, "I do not have to return to Washington.  It is of the
utmost importance to catch these spies and the government could well
afford to give up one ordinary doctor in order to get four skilled spy
hunters."  He paused and smiled, then added: "So I have been detailed
to special duty in New York."

The boys could hardly repress a shout of joy.

"And my instructions," continued Captain Hardy, "were to get into touch
with the police and the secret service immediately.  As I have told
you, we must get acquainted with both.  But before we do, I suggest
that we take a look at the town where we are to work in the days to
come.  Let's be moving."

They rose and passed through the station.  Its great vaulted ceiling,
half as high as a church steeple, its huge flights of steps, its
enormous corridors, its wonderful stonework, dwarfing into
insignificance anything they had ever seen before, fairly awed the boys
from Central City.  It was Roy's keen eye that caught sight of the
great maps of the world high up on the walls.  The crowds of people
coming and going hardly seemed like crowds, so vast was the structure.
With reluctant feet the four boys pushed on.  But when they had mounted
the steps to the arcade and caught sight of the illuminated
transparencies showing scenes along the railway's path, they came to a
dead stop.  For Willie Brown, with his almost uncanny eye for
landscapes, at once declared that a certain picture represented a
mountain scene not twenty-five miles from Central City; and when the
others appealed to Captain Hardy, the latter confirmed Willie's
statement.

When the four lads reached the sidewalk they were almost distracted.
Thousands of people were hurrying along, passing in endless throngs up
and down the street.  Never had the boys from Central City seen people
in such a rush.

"What's the hurry?" demanded Roy.  "Why does everybody walk so fast?
What's up?"

"Nothing," replied Captain Hardy, with a smile.  "That's just the New
York gait.  Everybody walks fast here, and does everything else fast;
and if you boys want to make a reputation in New York you'll have to
hustle some.  But I don't want you to make that kind of a reputation,"
he continued, hastily yanking Willie Brown from in front of a passing
motor-car.  "You will have to keep your eyes open here."

And indeed they had to.  Motor-cars were rushing about as numerous as
flies in August.  Trolley-cars followed one another up and down Seventh
Avenue in endless processions.  Wagons and trucks stretched along the
highway in slow-moving lines as far as the eye could see.  Bells were
ringing, whistles tooting, horns blowing, motor-cars honking, newsies
shouting.  The grinding of car-wheels, the rattle of carts, the clatter
of hoofs on the asphalt, the shuffling of feet on the sidewalk, and a
thousand other noises combined to make an indescribable and confusing
roar.  The noise and bustle were bewildering.

"I guess mother was right," thought Henry.  "It would be mighty easy to
get lost here.  The wireless patrol will have to look sharp or the
police will be called upon to find it."

And indeed there were so many distracting things that the four spy
hunters found it difficult not to get lost.  At every step something
new and unfamiliar claimed their attention and caused them to pause and
look about.

Captain Hardy let his charges go at their own gait.  He paused when
they wanted to look at something, took sharp care of them at crossings,
and told them how to cross the streets so as to avoid accidents.  And
ever he kept his eye on them to see that none of the four became
separated from the group.  It pleased him to note how quickly they
learned to avoid the traffic and dodge difficulties.  Their training in
observation had not been in vain.

To Herald Square the captain led his party.  There, in a little eddy of
sidewalk traffic, he drew them together.

"The streets that run lengthwise of the island," he said, "are called
avenues, and the one before you is Sixth Avenue.  The station we just
left faces on Seventh Avenue.  The cross streets are numbered, and the
one we are on is Thirty-fourth Street.  Broadway comes up the island on
a long diagonal.  Right here where Broadway, Thirty-fourth Street, and
Sixth Avenue intersect, is one of the busiest corners in the city.
Overhead are two elevated railway tracks.  On the ground are six
street-car tracks, crossing one another.  Under the surface are two
subway tracks.  So you have three layers of people passing and
repassing above or below one another.  I want you to remember what I
have said as to the arrangement of the thoroughfares--avenues run north
and south, streets east and west.  If you get that thought in your
mind, you won't go very far out of your way.

"And there is one thing more to remember.  In some cities, such as
Philadelphia, the street numbers run 100 to each block.  Here the
houses are numbered consecutively, and you can't tell by a number where
a house is.  But if you should need to know, go to the nearest drug
store.  Every New York drug store has a city directory.  And in the
back of the directory you will find a table that will show you
approximately where to find the street number you want.  Don't forget.
If you are to do effective work, you must become so familiar with New
York that you can find your way around as readily as you can in Central
City.  Sometimes it may be necessary for you to go from place to place
in the shortest possible time and you must know not only how to get
there, but also how to take advantage of short cuts.  We'll get some
maps after a time and study them."

His young companions plied their leader with a thousand questions.
They wanted to know the names of all the big buildings in sight.  They
had all heard of the Waldorf-Astoria Hotel and they gazed up
Thirty-fourth Street at this well-known hostelry with much curiosity.
They had heard of the Times Building and were eager to see it.

"We can't spend much time sightseeing just now," said Captain Hardy.
"We must get into touch with the police and the secret service people
and get our instructions.  Then we will take a day or two, if possible,
and see something of the town.  It is most important for you to become
well acquainted with it at once.  But I guess we can take time to slip
up to Times Square.  It's only eight blocks up Broadway.  Now I want
you boys to see everything you can as we go along, and to try to
remember all that you see.  Wherever you go you must remember that you
are in New York to detect German spies and presumably to run down
German wireless outfits.  We don't know where they are.  We may be
looking at one this very instant.  So keep your eyes open.  If you see
anything that resembles a wireless outfit, or that might be used for
sending messages, take careful note of it.  And keep your ears open for
suspicious conversations.  Because you are boys, people will be less
careful in their talk when you are present than they would be with
older people about.  The more youthful and unsophisticated you can make
yourselves appear, the better it will be for your purpose."

Slowly the little party made its way up Broadway.  By degrees the lads
became accustomed to the roar of the traffic and the rush of
pedestrians.  At Times Square they paused for a look at the great
newspaper building that gives the place its name, and at the great
hotels rising on every side.  Then they passed down a long flight of
steps and found themselves in a low, vaulted, underground subway
station.

"Makes you think of the dugouts on the firing-line in France,"
suggested the quick-witted Roy.

An instant later a train thundered up to the platform and the boys
boarded it.  A short ride and a short walk took them to Police
Headquarters.

Captain Hardy sent his card to the Police Commissioner, with the
request for a brief interview.  A few moments later he had presented
his credentials and introduced his companions, and four delighted boys
found themselves blushingly shaking hands with New York's famous chief
of police, Arthur Woods.  Briefly Captain Hardy stated the purpose of
his visit and related the story of the capture of the Elk City
dynamiters.

"I recall the incident distinctly," said the Commissioner.  "The
newspapers were full of it.  And I recall that when I read the story I
wished I had as accomplished and clever a squad of boys to help me with
some of my hard problems."

The four boys flushed with happiness.  But they were too much
embarrassed to make any reply.

"Captain Hardy," said the Commissioner, "what is your plan of action?"

"We have none as yet.  We are to work under the direction of the secret
service.  But we have not seen Chief Flynn yet.  The boys just arrived."

"Let me make one suggestion to you," said the Commissioner, turning
again to the boys.  "Before you attempt to do any detective work make
yourselves familiar with the city.  Get some maps and study them until
you know every street and alley.  Take your maps and go over the city
on foot.  Put several days in at it.  Become acquainted with the
water-front, the piers, the surface cars, the subways, the ferries.
Learn the city so that you can get around rapidly.  Make the
acquaintance of as many policemen, wireless operators, secret service
men, and other persons as you can.  Don't forget that a kind deed or a
thoughtful act will help you to make friendships quicker than anything
else; and make all the friends you can.  In police work you never know
who will be of assistance to you.  And above all things don't talk.
Don't tell a living soul about your purpose or your plans.  Let Captain
Hardy do that if it is necessary.  Secrecy is absolutely essential to
the success of your work.  Unless you can get along without betraying
yourselves you may as well go right back home.  Remember the spies you
are after are also after you.  If they learn what you are, they might
even take your lives."

"Commissioner Woods," said Captain Hardy, after a pause, "I have been
wondering whether or not these boys should have some kind of passes
that will enable them to get through the police lines.  There may come
times when it is of the highest importance that nothing shall interfere
with them.  What do you think about it?"

The Commissioner considered for a moment.  "If I were sure they could
be trusted with----"

"They can," interrupted Captain Hardy.  "Absolutely."

"Very well then."

The Commissioner pressed a button on his desk.  A clerk entered the
room.

"Make out special police cards for Captain Hardy and these four lads,"
he said, naming the boys.

Again he turned to the young spy hunters.  "The cards you are about to
get," he said, "will pass you by any policeman or put you through any
police line.  Do not let any one know you have them and never use them
unless you absolutely must.  It is best that not even the police should
know who you are.  Be very careful not to lose your cards."

"We will make some little cloth bags," said Henry, "and carry the cards
in them inside of our underclothes."

"I see that you are resourceful," smiled the Commissioner.

The clerk returned with the cards and handed them to Captain Hardy.

"Before you go," said the Commissioner, "perhaps you would like to see
our wireless department and get acquainted with Sergeant Pearce who is
in charge of it."

He summoned a patrolman to guide them to the wireless rooms and wished
the boys success.

A few moments later Sergeant Pearce was showing them the apparatus.
Two operators sat at a wonderful Marconi outfit with receivers clamped
to their ears.  In another room various instruments were installed here
and there, the walls were covered with diagrams of wireless instruments
and outfits, and lines of men were sitting at long tables with
receivers at their ears.  It was the police wireless school.  High
above the roof the aerial hung, suspended between the main dome and a
smaller dome at one end of the building.

"We are going to equip every station-house with wireless," said
Sergeant Pearce, "and the men you saw at work in the school are being
trained for operators.  We have put wireless outfits on some of the
patrol-wagons and on the police boat _Patrol_, so you see we can get
into touch instantly with any precinct or with the _Patrol_ no matter
in what part of the harbor she may be.  And when you have as big a
harbor as we have, with several hundred miles of waterfront, that means
something."

From Police Headquarters the little party went directly to the Post
Office Building, near the Brooklyn Bridge, to see Chief Flynn.  He was
a large, heavy man, with black hair and eyes and a short mustache.  He
shook hands with each of the party, and gave each a searching look.  He
spoke quietly but right to the point.

"I had word from Washington about you," he said.  "Do you know anything
about the city?"

The boys admitted their ignorance.

"Then your first job is to get acquainted with New York.  Get some maps
and guide-books.  While you are getting your bearings you can establish
a wireless watch.  I have a number of outfits in different parts of the
city.  For the next week or two, while you are getting acquainted with
the city, I want you to maintain a twenty-four-hour watch at a place I
shall send you to.  Divide the time among you so that some one is
listening in all the time.  Here are the call signals of all the
legitimate plants you will hear, either on land or water.  Pay
particular attention to call signals.  If you catch one not in this
list, be sure to get every word sent and let me hear from you at once.
We have other operators listening in for messages of the usual
commercial wave lengths and for very long wave lengths, so you need
watch only for messages of less than three hundred meters."

He wrote an address on a slip of paper and gave it to Captain Hardy.
"Go there," he directed.  "A wireless outfit has been installed and
accommodations await you."

He took the slip of paper from Captain Hardy and wrote some figures on
it.  "That," said he, "is my private telephone number.  But do not
bother me unless you get hold of something important."

In another moment the wireless party found itself in the rush and roar
of lower Broadway.




CHAPTER V

THE MESSAGE IN CIPHER

The house to which Chief Flynn had directed the wireless patrol proved to
be a private residence on a side street that ran between Central Park and
the Hudson River.  It was a tall house, standing two stories higher than
any other structure in the block.  Like most of its neighbors it had
evidently seen better days.  In places the brownstone front was cracked
and great chips had flaked off.  The broken stones in the long flight of
steps that led up to the first floor were patched with colored cement
that had faded so the patches stood out baldly.  The brass handrail above
the stone balustrade was battered and dirty.  Altogether it was not a
very attractive looking place.

The old lady who opened the door eyed them sharply.

"A gentleman named Flynn recommended me to your place," said Captain
Hardy.  "We shall need accommodations for quite a while."

"You must be the gentleman from Washington that he 'phoned me about.  You
are Captain Hardy?"

"I am."

"Come in," said the landlady cordially.  "Any friends of Mr. Flynn's are
welcome.  Your rooms are ready for you.  Mr. Flynn said you wanted to be
together, so I have given you the entire top floor."

She led the way up one narrow stairway after another until the party
reached the top floor.  There she threw open the door to the front room
and withdrew.

An exclamation of pleasure burst from the lips of the four boys.  The
shabby exterior of the house and the dim and dingy hallways through which
they had come gave no hint of the cozy comfort that awaited them.  The
room they now entered was of generous size, with soft gray wallpaper and
white woodwork.  Along one side ran low, well-filled book-shelves.  In
the middle of the opposite wall, with fire-making materials already piled
in it, was a small open grate, surmounted by an attractive mantel of
white woodwork.  There were a writing-table, a comfortable couch, and
easy chairs.  And what was most unusual for a city house, the room
possessed windows on three sides--two overlooking the street and one
giving a view over the housetops on either side.  A door at the rear
opened into a second room that was equipped as a writing room, with a
broad table and several straight-backed chairs.  Here, too, was an open
grate set in a white mantel.  In the room behind this were a number of
cots.  Back of all was the bath room.  A snugger and more comfortable
place it would have been hard to find.  But nowhere was there anything
that suggested a wireless outfit.

The boys looked at one another questioningly.  "He said there was an
outfit here," said Lew, "so there must be.  But I don't see where it can
be."

"It would be somewhere by itself," said Roy, "so that the operator
wouldn't be disturbed.  It must be on another floor."

"But if we are to keep a twenty-four-hour watch," argued Henry, "it ought
to be right in our apartment."

"Let's look at the aerial, anyway," suggested Lew.

A door at the end of the hallway quite evidently led to the roof.  They
had noticed it as they followed their landlady up the stairs.  Willie led
the way through it and the boys found themselves on the roof, which, like
the roofs of most city houses, was flat.  Like its neighbors, also, this
roof was encumbered with a number of long, wire clothes-lines, but the
boys found nothing that suggested an aerial to them.  Puzzled, they
returned to their apartment.

Presently there was a rap at the door.  Captain Hardy opened it and a man
dressed as a waiter, whom they had seen in the hallway as they entered,
stepped into the room.

"I came to show you your outfit," he said.

Stepping into the writing room, he grasped the corners of the mantel and
gave a sharp pull.  The entire upper half of the mantel swung outward and
came to rest on the writing-table, revealing a compact but wonderfully
well-equipped wireless outfit, including even a wireless detector for
telling the direction a wireless message came from.  The boys stared in
astonishment while the waiter grinned.

"What kind of a boarding-house is this, anyway?" asked Lew.

"This ain't no boardin'-house," replied the man.  "This is a sort of
headquarters for secret service men from out of town."

"Where's your aerial?" demanded Willie.

"If you go on the roof you'll see it--that is you will if your eyes are
sharp enough."

"I'll bet it's those wire clothes-lines," said Willie.

"Nothin' wrong with your eyes," said the waiter with a smile.  "But I
guess there wouldn't be, if the Chief sent you here."

Naturally each of the boys was eager to test the outfit before them.
They crowded round it, sliding the coil, shifting the condenser,
examining this and that, and voicing their approval and pleasure in the
different instruments.

"We may as well begin our watch at once," said Captain Hardy.  "Each of
you will have to listen in six hours a day.  If we divide the watches
into two tricks of three hours each, it will be easier for you."

The matter was arranged accordingly, and the first trick given to the
most experienced operator, Henry.  After the others had seen him take his
seat and adjust his receivers to his head, they withdrew from the
wireless room.

But Henry was far from being in solitude.  Sitting apparently alone, he
was listening to a multitude of voices; for before beginning his vigil he
wanted to test out his instruments and see how well they worked and how
sharply they would register sounds.  So he sat at his table, tuning now
to this wave length and now to that, now catching a land message and now
one from the sea.  Distinctly he caught the signal NAA from the great
navy wireless plant at Arlington.  He recognized it before the operator
had finished sending his call signal.  Night after night with his
home-made outfit at Central City, Henry had heard this station send forth
the time signals at ten o'clock; and during his brief period as radio man
for Uncle Sam he had often talked with Arlington, both sending and
receiving messages from the great station.  But though he recognized the
voice, he did not know the language he heard; for Arlington was flinging
abroad a message in the secret code of the navy.  Press messages and
commercial communications were buzzing through the air like swarms of
bees.  Orders to departing steamships came surging over his line.
Suddenly a strong whining note filled the air, drowning out all other
notes, and Henry knew the Brooklyn Navy Yard was talking.  He caught
messages from the Waldorf, from the Wanamaker station, from the police
wireless.  Never had he heard so many messages or imagined that the air
could be so filled with talk.  And had he not been a very able operator,
he would have been so confused by the babel that he would have understood
none of it clearly.  But he tuned sharply, shutting out interfering
vibrations, and caught clearly message after message.  But every message
that he intercepted was sent by a regularly licensed station.

After he had sufficiently tested his instruments, and assured himself of
their ability to register even the faintest sounds sharply and
distinctly, Henry shifted his coils and condensers again and began to
listen in for messages of less than three hundred meters' wave length.
Instantly the room that had hummed with voices grew silent as a cave.  No
message, no vibrations, no whisper of sound came to his waiting ears.
For three hours he sat, continually shifting his coils, but he heard
nothing.  As well might he have sat three hours by a rock, waiting for it
to speak.  And well he knew that this was only the first of many long
weary watches that would be kept ere the voice they looked for would come
out of the air.

Vividly Henry recalled the long vigils at Camp Brady, when he sat for
many hours at a time listening for the call of the dynamiters.  He
remembered how irksome that had been.  He remembered the chill of the
night and the silence of the great forest.  Here the watchers would be
more comfortable, but the vigil was likely to be as tedious and trying as
their watch in the Pennsylvania mountains had proved.  But that watch had
been rewarded.  The dynamiters had been located and captured.  And Henry
never doubted that this vigil, too, would meet with success.  So he
schooled himself to patience and keyed his ear and his instrument to the
keenest pitch.

Meantime his companions had lost not a moment in beginning their study of
the city.  When Captain Hardy emerged from the wireless room, he ran his
eye over the contents of the bookshelves; and one section he discovered
was filled with maps and guide-books and local histories, not only of New
York but also of other American cities.  He found a large-scale map of
the metropolis and spread it out on the table, true to the indicated
compass points.  Clustered about this outspread map, the other members of
the patrol followed with eager eyes and retentive minds their
instructor's every word.

Dr. Hardy called their attention to the contour of Manhattan Island, long
and tongue-shaped, and running almost north and south.  He showed them
the main thoroughfares, the great arteries of north and south traffic.
He traced for them the routes of subway, surface, and elevated car lines.
Together they located the tunnels and the ferries.  They studied the
harbor and the different shipping districts, coming quickly to know where
the transatlantic liners docked, where the coastwise steamers were
berthed, and where tramp steamers could find safe anchorages.  They
examined the harbor and adjacent waterways.  They studied the locations
of police stations and hospitals, of passenger stations and freight
depots.  They noted the location of the forts.  They identified the sites
of the largest buildings.

When they had finished with Manhattan, they studied one by one the other
boroughs--the Bronx, the boroughs east of Manhattan, Staten Island, and
finally the Jersey shore, searching always for what would lend itself to
spying or the use of a secret wireless.  Especially they studied all that
related to ships that cross the Atlantic.

Not in one evening or in one day was this accomplished, but through the
long hours of many days, as one boy after another took his turn at the
wireless.  And between tricks at listening in or studying maps and
guide-books, they roamed the streets, traveled on subway and surface and
elevated trains, crossed the ferries, rode in the sightseeing motors,
visited the bridges, the museums, the public buildings, and within a
short time knew more about the topography and geography of the city than
nine-tenths of the people who lived in it.  As they became accustomed to
the noise and the confusion and were able to find their way about with
ease, they scraped acquaintances on every side, and soon knew a multitude
of newsies, porters, policemen, truck drivers, car-conductors, and others.

Hour after hour, day after day, night after night, they listened in.  A
week passed.  Then another went by.  But excepting for one or two
snatches of talk, seemingly innocent, the watchers at the wireless caught
nothing.

Then, as Roy was listening in one noon while his comrades were
down-stairs at luncheon, there was a sudden buzzing in his ear.  Rapidly
he shifted coil and condenser until the vibrations came sharp and clear.
A call was sounding.  2XB was calling 5ZM.  Roy seized his pencil and
copied the signals, at the same time trying hard to locate the direction
from which the signals came.  It was well that Roy was a fast operator,
for the message that followed came with such rapidity that it taxed Roy's
ability to catch it.  But he managed to get every letter.  When the
message was ended, Roy reached for his list of stations and rapidly ran
through it.  The stations he had overheard were not listed.  There could
be no doubt about it.  He had caught a message from a secret wireless.
He turned to the paper with the message.  Here is what he had written
down: SRPSTSNIAOLTMIXNREHONTSTFIRG.  But he could make no sense of it.
The letters would not form themselves into words, combine them as he
would.  He rose and ran to the dining-room with the paper.

Captain Hardy studied it for an instant.  "Take this at once to Chief
Flynn," he said.  "He may want to ask some questions about it.  Willie
will relieve you at the wireless."

Several hours passed before Roy returned, and Captain Hardy began to fear
lest, despite the training in the geography of the city, Roy had become
confused and gotten lost.  Then suddenly the door of the wireless
apartment burst open and Roy flew in.

"Chief Flynn told me he thought his men could unravel that message and
that I should wait a while," panted Roy, breathless from running up the
stairs.  "And they did get it.  It's what they call a transposition
cipher.  Here is what it says."

He held out a sheet of paper.  On it the letters Roy had picked out of
the air were arranged in four lines, as follows:

  S R P S T S N
  I A O L T M I
  X N R E H O N
  T S T F I R G

"Read down instead of across," explained Roy.

Captain Hardy studied the cipher a moment more, then read aloud: "Six
transports left this morning."




CHAPTER VI

A NEW DANGER POINT

For a moment there was dead silence.  Then Captain Hardy spoke.  "You
have done excellent work, Roy," he said.  "Beyond doubt this is a
message from a German spy.  It is fortunate you caught this particular
message, for it proves that, whether there is a leak in the navy
department or not, the Germans are watching our ships here in New York.
Did you catch the direction this came from, Roy?"

"Yes, sir.  I marked the direction on the blotter beneath the detector."

"We'll take a look at it," said the leader, and the little band entered
the wireless room, where Lew was now on duty.

On the white blotter they found a long black line, tipped with an angle
mark like an arrow-head.  Captain Hardy got a map of the city, and
spreading it on the table true to the compass points, stretched a
yardstick across it in the direction indicated by the arrow.

"Hoboken," he muttered.  "The arrow points to Hoboken." For a moment he
studied the map before him.  "You will remember," he said, looking up,
"that Hoboken is the point on the Jersey side of the Hudson where there
are such great railroad freight yards and such huge piers.  Many
Atlantic liners sail from Hoboken.  Evidently the Germans are watching
there.  Of course they would be.  Their spies are informing other
German agents every time a troop ship sails.  And somehow they get that
news to Germany.  It's a terrible menace to our army, boys.  We must
put an end to it."

"We will," came the reply from four sober-faced boys.

"It's going to be a long task, boys," said Captain Hardy.  "Get your
hats and we'll take a look at Hoboken."

Leaving Lew at the wireless, the four others set out.  They rode for a
distance on a Ninth Avenue elevated train, then walked to the ferry,
and in less than an hour of the time they left their headquarters found
themselves in the great Jersey shipping point.

Never had the boys from Central City seen anything quite like the
water-front at Hoboken.  The level ground was one great maze of
railroad tracks, freight depots, warehouses, and pier sheds.  The wide
thoroughfare running along the waterfront presented a scene of
bewildering confusion.  Trolley-cars, steam trains, motor trucks,
horse-drawn vehicles, and other conveyances were moving this way and
that.  Whistles were tooting, motors honking, bells ringing, drivers
swearing, policemen shouting orders.  Pedestrians were dodging in and
out, messenger boys were darting here and there.  Porters were carrying
bundles on their shoulders, laborers were wheeling materials in steel
wheelbarrows, lines of heavily laden trucks were passing into steamship
piers, and guards and watchmen at every entrance were closely
scrutinizing all who approached.

The four observers walked slowly along, studying every foot of the way.
High fences had been built here and there to hide what was going on
behind them.  Covered ways led from railway terminals to pier sheds so
that none could see what had come by train.  Even the gangways to the
ships were screened.  Every precaution had been taken to baffle curious
eyes.

"They've done their best," commented Captain Hardy, "but they can't
screen a ship on the river, and the Germans know when our transports
sail, even if they don't know what's in them.  Any one with a good
glass can look out from any house along the river front and see clearly
every move made by a steamer.  Let's take a stroll among these houses."

They left the bustling water-front and passed to the higher ground
where stood the city proper.  It was like most other American
municipalities--dirty, dingy, and unattractive, a hotchpotch of
buildings with no architectural unity.  But it had one feature
possessed by few cities--an outlook on a great and busy harbor.

As the boys stood looking at the rolling Hudson below them, watching
the ferry-boats come and go, like huge shuttles in a giant loom,
following the movements of steamers, and tugs and tow-boats, and
tracing the circling flight of the gulls, they forgot entirely the
errand that had brought them.  Presently their leader broke the silence.

"We shall have to get to work," he said.

Starting at one end of the street, they walked slowly along its entire
length, studying every house that fronted on the river.  They saw at
once that their task was hopeless.  Square after square the houses
stretched in unbroken blocks.  A hundred spies might be living in those
houses and no one be the wiser.  A hundred wireless outfits might be
flashing messages among the clothes-lines on the roofs and only a roof
to roof survey would reveal the fact.  But it was not necessary to run
even so slender a risk of discovery.  As the wireless patrol knew only
too well, an aerial would work with great efficiency even though it
were strung in a chimney or erected entirely within doors.  Yet the
little party continued its investigation until dusk, scanning every
window whence a glass might be directed toward the river, and threading
alleys and scrutinizing the wires of roofs and yards.  But nowhere did
they see anything to arouse their suspicion.

"We may as well go back, boys," their leader said at last.  "We shall
have to depend upon our ears rather than our eyes if we are to catch
these villains.  But we have made progress.  We know where they are.
We have limited our field of observation to one place.  Now we shall
have to do as we did at Elk City.  We shall have to get two portable
sets with compact detectors and begin a watch in Hoboken.  We'll have
to find this hidden wireless by triangulation, just as we caught the
dynamiters.  But we haven't enough of a force to maintain two watches.
We shall likely have to send for more of the boys to come on."

They recrossed the river and made their way back to their headquarters.
Lew had heard nothing.  He was relieved by Henry.

The others went down to dinner, and food was sent up to the lone
watcher.  But when his trick was ended, he made the same report that
Lew had rendered.  He, too, had heard nothing.

"Doubtless," said Captain Hardy, "they use their wireless seldom for
fear of discovery.  Probably they send a message only when troop ships
have actually sailed.  That is likely the reason it was such a long
time before we caught the first message.  And it may be just as long
before we hear another.  But when it comes, we must be ready with our
two detectors.  I'll see Chief Flynn about them in the morning.  And
I'll tell him what we have learned in addition to what the cipher
message told us."

"I wonder," said Roy, "how the secret service men ever unraveled that
cipher.  I could never have done it.  I was looking for something like
the code message we caught at Camp Brady."

"It probably was not very difficult, Roy," replied Captain Hardy, "or
it could not have been fathomed so soon.  I believe that most cipher
messages to-day are like the one you caught at Camp Brady.  Apparently
they are innocent messages but they have a hidden meaning.  The most
difficult cipher messages, I have heard, are of the substitution kind,
where many alphabets are used.  It is pretty difficult to decipher such
messages unless you have the key word."

"Then why didn't the Germans use a substitution cipher when they sent
this message about the transports?" asked Willie.  "Then we might never
have been able to tell what they said."

"It was hardly worth while, Willie.  They know the authorities are
listening for their messages.  It made no particular difference if the
contents of this message were known.  But when they send out an order
for a spy to do something, I have no doubt they use the most difficult
code they can devise, or at least one that they believe only the spy
will understand.  So we may expect to catch messages in different codes
before we are through with our work."

Captain Hardy rose and began to look along the shelves of books.  "Here
is a volume," he said presently, "that will tell us a great deal about
cipher messages."

He had just laid open the book when Roy rushed in from the wireless
room.  "I've got another message," he said, holding out a paper on
which was a long string of letters.

"I wasn't expecting another message so soon," said Captain Hardy in
surprise.  Slowly he read the letters on the paper Roy had given him:

  "FTSTITEIAFTDLLTNSYWTORPSLHVNRLEEYLIOTEIH
   UAOSEIEGGEVNCENDRRTERNRADSNLEEITOCGEOSHM."

"It looks like the same cipher used before," he went on.  "If it is, we
can unravel this message without bothering the secret service.  At any
rate we'll make a try at it.  Where's that other message, Willie?"

The first message was brought.  Captain Hardy spread it on the table
and the group bent over it.

"The letters divide evenly into four lines, you notice," said the
leader.  "Let's see if this message will do the same."

He counted the letters with his pencil.  "Eighty," he announced.  "That
would make four lines of twenty letters each.  We'll try it."

Rapidly he copied the first twenty letters.  Below them he made a
second line of the next twenty letters.  Then the third set of twenty
was written down.  As he began the fourth row the three boys at his
side held their breath.

"He's got it," Willie Brown cried, as Captain Hardy wrote down the
first letter.  "He's got it.  It spells four."

Rapidly Captain Hardy finished out his line.  The letters he had
written down read like this:

  FTSTITEIAFTDLLTNSYWT
  ORPSLHVNRLEEYLIOTEIH
  UAOSEIEGGEVNCENDRRTE
  RNRADSNLEEITOCGEOSHM

He picked up the paper and slowly spelled out the following message:

  "Four--transports--sailed--this--evening--
  Large--fleet--evidently--collecting--
  No--destroyers--with--them."

For a moment there was complete silence.  Then Henry spoke.  "They can
see everything in Hoboken," he said.  "It's a wonderful place to spy
from."

"That message didn't come from Hoboken," said Roy, who had been
listening to their conversation with one ear while he kept his receiver
at the other.  "It was for 5ZM all right, but it was signed 2XC instead
of 2XB and the detector doesn't point toward Hoboken."

There was a rush for the wireless room.  Captain Hardy seized a map,
spread it on the table, and again applied the yardstick, extending it
in the direction indicated by the detector.  The stick pointed straight
toward the Narrows, at the entrance to the harbor.

"That message came from Staten Island," said Captain Hardy with
conviction.  "They have got two secret stations."




CHAPTER VII

CONFUSION WORSE CONFOUNDED

As the possibility of this new difficulty rose before them, the members
of the wireless patrol were almost staggered.  They knew how difficult
it had been to locate the hidden wireless in the mountains at the Elk
City storage reservoir, where there were no other wireless plants to
distract them and no houses to conceal the apparatus.  The obstacles
now before them appeared almost insuperable.

The silence was broken by their leader.  "I suppose we shall not learn
anything, but at least it will be better to look the ground over.  So
in the morning we'll run over to Staten Island."

Morning found Henry on the wireless watch.  Lew's trick was to follow.
The two others and Captain Hardy left the house immediately after their
breakfast and set off for Staten Island.  In order to see something of
the city as they journeyed, they went on the Ninth Avenue elevated
road, and in half an hour found themselves at South Ferry, whence the
city-owned ferry-boats leave for Staten Island.  It was their first
visit to this ferry and they were impressed by the fine waiting-rooms
and the magnificent ferry-boats.

The trip down the harbor thrilled them with pleasure.  The narrow
channel between Manhattan Island and Governor's Island seemed to be
filled with snorting tugboats, strings of barges, great floats carrying
many loaded freight-cars, puffing steamships, and even sailing vessels.
Whistles were tooting on every side as pilots signaled to one another.

"I don't see how they ever manage to keep from smashing into one
another," said Willie as he stood with wide eyes, watching the rapidly
moving craft about him.

"They don't always," said Captain Hardy.  "But accidents are
surprisingly few."

Hardly had they gotten up speed before they passed close to Governor's
Island, the military reservation which was the army headquarters for
the Department of the East.  With great interest they looked at Castle
William, the great circular stone fort, now useless for protection, but
venerable with age and tradition, that stood at the western edge of the
island.

Soon they were past the island and out in the open bay.  Far to the
left were the Brooklyn shores, with their great shipping terminals and
stores and clustered steamers.  On the right, and still more distant,
ran the low Jersey coast, almost hidden in fog and smoke.  Against this
dull background towered the Statue of Liberty.  Reverently the boys
stood looking at this great image, known the world over as no other
statue is known, and symbolic of all a free earth holds dear--symbolic
of that liberty, fraternity, equality that the free men of the world
are giving their lives to preserve.  A mist rose in their eyes as they
looked at this symbol of that which they, too, were giving their
devoted efforts to preserve--their homes, their families, their
freedom.  And on every face came a set expression of determination
that, even though the countenances wearing it were youthful, boded no
good to the treacherous enemies of freedom whose trail they were that
very moment following.  Then they flashed past Robbin's Reef light and
snuggled into their slip at Staten Island.

Before them towered the community of St. George, straggling, like some
old world village, up the sloping streets to the heights.  Quickly they
climbed a winding road that led to the top of the hill.  Like Jerusalem
the golden, the village about them was beautiful for situation.  For
miles it commanded an unobstructed view in almost every direction.  To
the north were the rolling reaches of the Upper Bay across which they
had come, with the tall sky-scrapers of Manhattan towering heavenward
in the background and looking so near at hand that it was hard to
believe that they were six miles distant.  Shaped not unlike a pear,
the great Bay tapered to stem-like dimensions as it flowed to the east
of Staten Island and found its way to that greater sheet of water, the
Lower Bay.  On the opposite side of this passage rose the bluff shores
of Brooklyn.  But the Staten Island shore towered high above everything
else.  On opposite sides of the narrowest parts of the channel to the
sea were forts.  And it was to this very Narrows that the wireless
detector had pointed when Roy caught the message on the previous night.

"From somewhere in this neighborhood that message came," said Captain
Hardy.  "And beyond a doubt it came from some house on the slope before
us.  From this view-point an observer can see everything that takes
place in both Upper and Lower Bay and spy on every vessel passing
through the Narrows.  With a powerful glass an observer on these slopes
could almost distinguish the buttons on the sailors' clothes or read
the compass on the bridge of a ship.  Let us see what we can find."

For a mile or two they walked leisurely along the brow of the hill,
carefully examining every house that possessed a good outlook over the
Narrows.  They found many such, but as was the case in Hoboken, the
houses were as like as so many peas.  In location or construction there
was nothing that would direct the finger of suspicion to one house
rather than another.  Any house with an unobstructed outlook might
harbor a spy.

When they had gone far enough along the brow of the hill Captain Hardy
said, "Let us go back along the slope.  I suspect any observer would
get as near to the water as he could and yet have sufficient elevation
for a wide view.  I believe the place we are looking for is somewhere
below us."

They climbed down to a lower level and began their return walk.  On the
slope the buildings were not so close together.  There were more open
spaces, more undeveloped stretches where trees yet remained and
thickets of underbrush still stood undisturbed.

"These houses would make better radio stations than those so closely
crowded together, I should think," commented Captain Hardy.

Slowly they sauntered along, stopping near every suspicious house,
ostensibly to view the landscape, and giving it a searching examination
as they took in the view.  And so artfully was their work done that no
one watching the eager group, looking now here, now there, would have
dreamed that ships and shipping were the last things they were
interested in.

Slowly they worked their way along the slope, now climbing to higher
levels, now descending to lower, as it became necessary to view a
habitation from one side or the other.  But search as they might,
nothing stood out in any place that was of a suspicious nature.  There
were no questionable wire clothes-lines, for here every one seemed to
use cotton lines.  No flagpoles rose aloft, up which antennas wires
could be hoisted in the guise of halyards.  No kites flew from back
yards.  No lightning-rods rose suspiciously above the housetops.  There
were no tall chimneys inside which hidden wires might be stretched.
Nowhere was there anything at which they could definitely point the
finger of suspicion.

Almost had they given up hope of finding anything that would help them,
when they came to a place where the slope jutted out sharply for a
little space, like the nose on a human face.  The ground sloped outward
for a distance at a gentle angle, then dropped precipitously many feet.
But on either side of the nose of land the even slope of the hill was
unbroken, just as human cheeks continue their uninterrupted slope from
the forehead.  Perched on this nose of land was an inconspicuous little
house.  As the surrounding land was too steep for habitation, this
house stood by itself, the slope for many yards on either side being
overgrown with bushes and undergrowths, while a considerable stand of
pines grew at one side.  The fenced-in yard of this house was large,
and by an ingenious system of curves a roadway had been built from the
public thoroughfare up to the little house.  Evidently the owner
possessed a motor-car, for a tiny garage was snuggled into the hill
beside the dwelling.

But the thing that at once attracted the little patrol was the view
afforded by the location.  Indeed it was _the_ view-point
strategically; for the jutting nose of land gave an unobstructed
outlook toward both Bays which could be had from no other location on
the same level, while the Narrows lay immediately below the house and
so close that it seemed as though one could throw a stone from the
little house into the water.

For several minutes the three searchers stared at the structure before
them.  "I believe," said Willie, in the language of blind man's buff,
"that we are getting hot."

"Let's look at the place from the other side," suggested Roy.

Slowly they sauntered along the highway, now examining the Narrows, now
watching some ship in the offing, but gradually working their way to
the other side of the little house.  Everywhere except at the rear of
the building, where the hill rose steeply, ornamental rows of windows
had been built into the structure, giving an uninterrupted view, north,
east, and south.

"I'll bet there are no partition walls in that floor," said Roy, "and
if there aren't, anybody could sit in the front of the house and look
in three directions by merely turning his head.  Why that place is just
made for spying on shipping."

"And it's exactly where our wireless pointed," said Willie.

"I wonder how we could get into the place and examine it."

"You mustn't think of such a thing," said Captain Hardy.  "If there is
a wireless outfit there, you may be sure that it will be as effectually
secreted as the one in our rooms is, and you would never find it.  But
you would certainly alarm the people in the house, and the Chief warned
me that under no circumstances should we alarm the people we are
watching.  We must get a complete case against them before any move is
made."

"But if this is a wireless station, how are we going to know it unless
we search the house?" demanded Roy.

"We shall have to keep a watch on the house itself and try to trail
everybody who goes in or out.  And we shall keep up our wireless watch.
If messages are coming from here we shall run them down just as we
intended to run down the Hoboken messages.  This place is so much
better for spy work, being near the forts as well as the waterways,
that we'll drop Hoboken and centre our efforts here.  But I don't know
just how we'll do it.  I'll have to let the Chief outline the plan.  We
may have to move down here.  But in the meantime you boys can keep the
place under observation very easily from some of these thickets."

The three went on down the road and passed out of sight of the house,
laying their plans as they went.  Arrived at the road to the ferry,
they separated, Captain Hardy continuing on down to the wharf, while
Willie and Roy turned about and retraced their steps.  While Captain
Hardy was speeding back to Manhattan to consult the secret service men,
the two young scouts made their way to a turn of the road whence they
could barely see a gable of the house on the cliff.  They had not met a
soul.  They left the highway and scrambled up the slope to a dense
thicket of underbrush.  Screened by this, they cautiously approached
the house and made their way unseen into the little stand of pines they
had previously noted.

The cover was good.  The pines on the outer edges of the stand, where
the light was ample, branched close to the ground, making a dense
hedge.  Behind these protecting branches the two boys could move freely
without fear of discovery.  By mounting upward a little distance, they
had a perfect view of the house they were watching, and could see all
who entered or left it.  They found some limbs where they could sit
comfortably and took up their vigil.

"Captain Hardy said we must trail anybody who came out of the house,"
said Willie.  "If we follow them on the road we could be seen and we
might be suspected.  How can we trail them without being seen?"

They looked around.  Higher up the slope ran another road, so hidden by
shrubbery and bushy growths as to be almost invisible from below.  A
person walking along this road could easily follow one on the highway
below without being seen.  A brief study of the slope also showed them
a bushy way by which they could scramble unseen up to this road.

Now they gave their undivided attention to the house before them,
studying every feature of house and grounds that they might be able, if
it became necessary, to make their way safely about the premises.  But
no one came to the house, no one left it, no one appeared at a window,
and there was no sign whatever that a living being was in the house.

The minutes began to drag.  It was uninteresting to sit and scrutinize
a house when there was so much of real interest to see.  So between
glances at the home on the cliff, the scouts began to study anew the
wonderful harbor that so fascinated them.

Again they studied those distant sky-scrapers, which looked, at the
distance, like dream buildings, deceptive structures of the clouds.
The waters intervening were palpitant with life.  As an hour passed,
and then another, the young watchers gave more and more attention to
the landscape and less to the house near by.  The air was vibrant with
the tooting of whistles.  The wind was sweeping the water before it in
graceful waves.  The passing steamers churned it into yeasty foam.
Great sailing ships came surging in from the deeps, deck-laden with
heavy cargoes, parting the water with their high bows, their sails
bellying in the breeze and shining white in the sun.  Tugs passed
restlessly to and fro, dragging behind them long strings of coal
barges.  And once a great ocean liner came in through the Narrows,
making the very hills vibrate with the thunder of her whistle.
Intently the boys watched her as she slowed at quarantine and the port
physicians boarded her.  By mere chance Willie turned his glance toward
the house on the cliff, and there, close to the front windows, stood a
man with field-glasses to his eyes, studying the liner in the Narrows
below.

"Look!" gasped Willie.  "There's a man in the window!"

But before Roy could turn his head the figure had disappeared.

"We almost missed him," said Willie.  "We're poor scouts to forget what
we are about."

They centred their gaze on the near-by house.  Forgotten was the
glorious picture spread before them, forgotten everything but the
glass-fronted dwelling and the invisible man with the field-glasses.
But look as they would, they could see nothing further of a suspicious
nature.  Another hour passed.  Dinner time had long gone by.  The one
o'clock whistle had blown.  And their own stomachs told them accurately
what time it was; but they would not leave their post.  Now that they
had once scented their quarry, as it were, or believed that they had,
they were like hounds on the trail.  Their training at Camp Brady now
showed its effect.

But the hours passed, the afternoon waned, and nothing further occurred
to draw their attention to the little house.  Gradually their vigilance
relaxed.  Their eyes wandered again to that fascinating harbor scene,
to the never-ending moving picture spread before them.  Again they saw
tugs and ferry-boats plying busily back and forth, and the flashing
sails of great schooners.  But presently they saw something like
nothing they had ever beheld.  Far in the distance was a line of moving
objects, gliding through the waves in stately fashion, approaching one
behind the other at equal distances.  Just what was approaching the two
scouts could not at first determine, so indistinct in outline were the
moving bulks.  But presently, as the oncoming objects drew nearer, the
watchers saw that they were great ships.  But they looked unlike any
ships they had ever seen or heard of.  They seemed to be of no color
and of every color.  They were streaked and splotched in the most
curious way.  They looked as though some giant hand had flung eggs of
different colors against their sides.

The boys looked at one another in astonishment.  "Well, what in the
mischief ails those boats?" demanded Roy.

They were silent a moment, becoming more amazed than ever.

"I know," cried Willie suddenly.  "They're camouflaged.  They must be
transports."  He turned his head for a glance at the house.  "Quick!"
he said.  "There's the man at the window again."

For some minutes the figure before them stood motionless except for the
movement of his field-glasses, with which he swept the oncoming fleet
of transports.  Then he drew back from the window again.  The boys kept
their eyes fastened on the little house.  For a long time nothing
occurred.  Then a grocer's boy came in sight, struggling up the highway
with a basket of supplies on his arm.  The watchers paid small
attention to him until he turned suddenly into the driveway leading up
to the house.  A moment later he had disappeared within the building.

"He's only a grocery boy," said Roy.

"We'll have to watch him, anyway," said Willie.  "I'll follow him when
he comes out and you watch the house."

They had not long to wait.  In a few minutes the boy came out, his
basket empty, and went skipping down the hill.  Quick as a flash Willie
scrambled to the roadway above, and, screened by the shrubbery,
followed on the higher level.  A quarter mile toward the ferry the two
highways came together.  Willie reached the intersection at almost the
same time as the grocer's boy.  Each took a glance at the other and
kept on his way, Willie dropping a few yards behind the other lad.

A quarter of a mile further on the slope changed and the district was
thickly built up.  The errand boy soon entered a store.  Willie had
just time for a quick glance at the sign on the window.  It read,
"Fritz Berger, Fancy Groceries."  Then Willie opened the door and
followed the errand boy into the place.

A florid, burly man with upturned mustaches stood behind the counter.
The errand boy was talking to him.  In his hand he held a silver dollar.

"Here is the money for Mr. Baum's sugar," he was saying.

"Good!" said the grocer, seizing the coin, which he dropped in his
pocket.  Then he turned to Willie.  "Well?" he said inquiringly.

"Sugar," said Willie.  "I want five pounds of sugar."

"I have no more," said the grocer.  "It is all sold."

"Pshaw!" said Willie.  "Where can I get some?"

"I don't know," said the grocer.

"Got any candy?" asked Willie.

"Sure.  In that case."

Willie walked to the show-case and slowly examined the stock.  "Give me
ten cents' worth of those chocolates," he finally ordered.

The storekeeper weighed out the candy and dumped it in a bag.  He took
the proffered dime, dropped it in his till, and turned away.

Willie left the store and stood for a moment undecided as to which way
to go.  "Nothing doing there," he said to himself.  Then he turned a
corner and started down the hill.  The supper hour was approaching.
People were coming up the street from the ferry, homeward bound from
Manhattan.  A motor-car came chugging up the road and drew close to the
curb.  The driver turned his car about, clamped on the brake, and
stepped out, leaving his engine running.  Willie went on down the
street and was soon in the midst of a throng coming up from the ferry.
He stopped to look at a jeweler's clock, turned about, and started on
his way to rejoin Roy.  Suddenly he heard the softly whistled signal of
the wireless patrol.  He turned sharply about and saw Captain Hardy
across the street.  He dodged a motor-car that was rooming down the
hill and crossed to his captain.  There had been no sign of life about
the little house since the grocer's boy came out.

"Come," said the leader.  "I have seen the Chief and he is going to
arrange it so that we can watch this place in comfort.  We will go back
home now."

They climbed cautiously to the road above.  "By George!" exclaimed
Captain Hardy suddenly.  "You boys haven't had a bite to eat since
breakfast.  I forgot all about that."

"How about yourself?" asked Roy.

"Well, I haven't either, but that's different.  I've had a chance to
get something if I had thought of it.  We won't wait until we get home
to eat.  There's a restaurant at the ferry-house.  We'll have a good
dinner there."

More than an hour passed before the three rose from their table.
Another hour had gone by before they reached their headquarters.  They
were tired and sleepy.  But their drowsiness vanished when Henry rushed
into the living-room of their apartment and thrust a sheet of paper
into Captain Hardy's hands.

"It's another message," he said, "and we deciphered it ourselves."

Captain Hardy stepped to the light and read the message aloud.  "Five
more transports sailed late this afternoon.  All camouflaged."

"We know the man who sent that message," cried Willie.  "We've been
watching him all the afternoon, down on the hillside at Staten Island."

"But this message didn't come from Staten Island," said Henry.  "The
detector points straight east over Brooklyn, and the message was sent
from a long way off.  It was very faint."




CHAPTER VIII

WHERE MONEY TALKED

For a full minute the members of the wireless patrol stared at one
another in speechless amazement.  Then Willie broke the silence.

"I don't care where it came from," he said.  "I just know that the man
we were watching sent it."

"But how could he have sent it, when the wireless pointed to Brooklyn?"
demanded Henry.

"Oh!  I don't mean that he actually sent it with his own fingers," said
Willie.  "But we saw him watching the ships and there isn't any other
place in the whole harbor where you can get such a good view of them.
I just know he had something to do with that message."

"I'll bet the Germans have got a string of wireless outfits and that
what he does is to stay in that house and spy on ships that pass
through the Narrows and then telephone to one of these secret wireless
stations," said the nimble-witted Roy.  "And if that's the case he
hasn't any wireless at all himself."

"If Roy is right," said Henry, "it's a pretty clever scheme.  The
secret service could take his house to pieces and not find a wire in
it.  Yet he's the man that's sending the messages, or at least starting
them."

"Roy is doubtless correct," said their leader.  "We know they have at
least three stations and they may have many more.  The object of that,
of course, is to baffle any wireless man who may be on their track.  If
we hadn't stumbled on this spy post at Staten Island, we should have
been completely blocked ourselves.  But we've got something definite to
work on now.  We've got a definite clue.  And sooner or later we will
uncover some of their hidden stations.  From now on we've got to watch
this man on Staten Island as well as listen for messages.  I don't see
how we are to do it unless we send for more of the boys or move to
Staten Island."

When the matter was laid before Chief Flynn he said no more boys were
needed.  Too many boys in one house would attract attention.  So he
arranged to transfer the wireless patrol to Staten Island.  Living on
the slope above the suspected house was a well-to-do but childless
couple with a rather large house, who were warm friends of the Chief's;
and they readily agreed, as a matter of service to their country, to
take the wireless patrol into their home.  So a wireless outfit was
installed, with a concealed aerial, and the boys found themselves
situated even more pleasantly than they had been before.

And it was well that they were pleasantly situated, for though their
task was not difficult in one sense, in another it was extremely
trying.  Six hours a day each boy sat at the wireless listening in.
Had it been possible to tune to longer wave lengths and pick up the
interesting news with which the air was fairly alive, the task would
have been anything but irksome.  But to sit hour after hour with their
instruments tuned to the short wave lengths used by the German agents
and hear nothing, was trying enough.  The watch on the spy's nest
proved hardly less tedious.  From a gable-window in the attic a very
fair view could be had of the little house below.  Here, on rainy days,
a watcher sat during all the hours of daylight; and on other days the
sheltering pines hid an observer.  But day followed day, night
succeeded night, and no message was registered on the wireless
instrument nor did anything suspicious occur in the house under
surveillance.

Indeed the fact that nothing did occur was in itself suspicious.  For
there was hardly a sign of life about the house.  No man left it in the
morning bound for business.  No woman emerged from its door to go
shopping of an afternoon.  For days at a time nobody entered or left
the place, excepting the grocer's boy who came with food.

Then one day a motor-car, with its top raised, chugged up the highway
and climbed the steep driveway to the house on the cliff.  Henry was in
the attic gable on watch and he promptly notified his comrades.  There
was a rush for the third story, and four heads crowded close together
as four pairs of eyes sought to identify the make and number of the
car.  But the name-plate was missing, and the license tag was so dusty
that the number could not be read.

"Run down to the pines with this, quick," said Captain Hardy, thrusting
his field-glasses into Willie's hand, "and get the number of that car.
See if you can tell what make it is and look for distinguishing marks."

Willie scrambled down the slope through the concealing shrubbery and
approached the house as near as he dared.  But he had hardly reached
his station when the driver ran down the steps of the house, sprang to
the wheel, and was off at a fast pace.  Willie climbed cautiously back
to headquarters.

"Did you get its number?" asked his chief.

"No," replied Willie.  "It was covered with dust.  And I couldn't tell
what make of car it was.  But I saw the driver and I am sure I have
seen him before and the car, too."

"That's not unlikely," said Captain Hardy, "if he lives anywhere near
here.  We've been here several days now."

"I'm sure I've seen that man somewhere," said Willie.  "I wish I could
remember where it was."

Another day passed and another, and still the little house on the cliff
showed no signs of life.  But one afternoon the monotonous watch came
to a sudden end.  Lew, in the attic gable, espied a fleet of transports
coming down the bay.  Instantly he spread the alarm.

"You boys slip down to the pines," said Captain Hardy to Willie and
Roy.  "If any one comes out of the house trail him.  Now we'll find out
whether this spy--if he be a spy--telephones his news or sends it out
by messenger.  The Chief has had the telephone wires tapped and is
receiving a record of all conversations."

Lew continued his watch aloft.  Henry sat tense at the wireless,
waiting to catch any possible message, and Roy and Willie scrambled
cautiously down to their favorite observation post in the pines.  On
came the transports, riding the waves in a stately column; yet the
little house seemed as lifeless as ever.

"Watch close," whispered Willie.  "Don't let anything escape us."

On came the ships, nearer and nearer, throwing the white spray away
from their bows.  They passed Robbin's Reef light.  They drew close to
the entrance to the Narrows.  Breathlessly the boys awaited their
nearer approach.  The transports reached the narrowest part of the
passage and still there was no sign of life in the little house.
Willie gave a sigh of disappointment and started to speak; but before
he could utter a word there was a movement in the window before them
and the man they had previously seen appeared for a moment sweeping the
Narrows with his glasses.  Then he disappeared from sight.

"It's him!" exclaimed Willie, forgetting his grammar in his excitement.
"Now he's either telephoning his message or getting it ready for a
messenger.  We'll soon know."

They had not long to wait.  A figure was seen coming up the highway.

"It's only the grocer's boy," said Willie in disappointment.  "This is
the time he usually comes."

"I wonder if we aren't on a wild-goose chase," said Roy.  "Maybe the
man in that house isn't any spy at all.  I begin to think so."

"I don't," maintained Willie.  "I just know he's a spy, but how he
sends his messages I can't figure out."

Just then the grocer's boy came out of the house.  "There's no use
trailing him," said Roy.  "We already know who he is.  While we're
following him the messenger might come--if there is one."

"Captain Hardy said we should follow any one who left the house," said
Willie, "so I suppose we'll have to watch this errand boy.  You go this
time, Roy."

In a minute Roy had reached the higher thoroughfare.  He ran down the
road at top speed and got to the grocery store before the loitering
errand boy even came up into this higher road from the lower
thoroughfare.  But instead of entering the store, Roy turned the
corner, retracing his steps in time to enter the store half a minute
before the errand boy got there.

The grocer was behind the counter.  "Have you any crackers?" asked Roy.

The grocer took down a package of Uneeda biscuits.

"You don't have any loose ones?" asked Roy.

"No, these are all we keep."

"Guess I'll have to take 'em," said Roy.  "Got any candy?"

"In the case there," was the answer.

Roy walked over to the show-case and began to examine the stock.  Just
then the errand boy came in.

"Here's the money for the sugar," he said, handing the grocer a silver
dollar.

The grocer took the coin and carelessly dropped it into his pocket.

Roy continued his inspection of the stock of sweetmeats.  "Give me five
cents' worth of gum-drops," he said.

The grocer began to weigh them out.  A tall man with gauntlets and with
motor goggles on his forehead came in.

"Hello, Fritz," he said jovially.  "Got that sugar for me yet?"

"Just sold my last ounce," said the grocer.  "I haven't been able to
get a bit for three days."

"Himmel!" said the customer.  "How much longer have I got to go without
sugar in my coffee?"

He turned to go.

"Hello!" called the grocer.  "Here's that dollar I owe you."

The man turned back, and the grocer pulled the coin from his pocket and
dropped it into the man's gloved hand.

"Good luck to you," he said, then finished weighing out the gum-drops
for Roy, and dropped the nickel in his cash drawer.

Slowly Roy retraced his steps.  "Well, what happened?" asked Willie, as
Roy rejoined him.

"Nothing," said Roy in disgust.  "The errand boy came in and handed the
grocer a dollar that he had collected for sugar.  Pretty soon an
automobile driver came in to get some sugar and the grocer said he
hadn't any more, but he paid him a dollar he owed him."

Willie was silent, turning the matter over in his mind.  "Then what?"
he asked after a time.

"Nothing, except that I bought some candy and the grocer put the money
in his cash drawer.  Then I left."

"Where else would he put it?" asked Willie, abstractedly, as he tried
to read some meaning into the grocer's apparently meaningless acts.

"Well," said Roy, "he didn't put the dollar the errand boy gave him
into the drawer.  He dropped that into his pocket."

"Why, that's exactly what happened when I was in there the other day,"
said Willie in surprise.

The daylight waned.  Dusk came on.  It grew too dark to see the spy's
house from the pines.  It was past time to relieve Henry at the
wireless.  The two scouts climbed to their own house for orders.  As
they came up the stairs they heard the voice of Henry.

"Come quick," he called.  "I've got another message."

Everybody rushed to Henry's side.  Captain Hardy seized the sheet of
paper from Henry's hand, and counted the long string of letters written
on it.  Quickly he rearranged them in four equal lines.  Then slowly he
read the cipher.  "Another transport fleet assembling.  First five
boats went to sea this afternoon."

"Where did this message come from?" he demanded, as he laid down the
paper.

"From some point down the Jersey coast," said Henry, "and probably not
more than twenty miles away."

A long silence followed.  "We're simply up against it," said Lew
dejectedly.  "We don't get anywhere."

Suddenly Willie jumped to his feet with a cry.  "I've got it!  I've got
it!" he almost shouted.  "Why didn't I see it before?"

"Got what?" asked Roy, astonished.

Willie paid no attention to his question.  "What sort of a looking man
was that motorist?" he cried.

"A tall fellow, with black hair and with a big scar on his cheek," said
the astonished Roy.

"I knew it," cried Willie.  "I knew it!  Now I know how the messages
are carried.  It's as plain as can be."

His fellows clustered about him.  "What do you mean?" said Captain
Hardy eagerly.  "Explain."

"Well," said Willie, "when I followed that grocer's boy the other day,
I saw him give the grocer a dollar which he said he had collected for
sugar.  The grocer put it in his pocket.  But when I gave him money for
candy he dropped it in his till.  Just after I left the store and
turned the corner a man drove up in a motor.  I noticed him because he
turned his car completely around and stopped at the curb.  He got out
and left his engine running.  When I crossed the street to meet you,
after you whistled, I dodged a motor-car.  It was the same car, but I
thought nothing of it." He paused, as though collecting his thoughts.

"Go on," said their leader eagerly.

"To-day," resumed Willie, "Roy followed that same grocer's boy from the
house on the cliff to the grocery store and saw him give the grocer a
dollar, which he said he had collected for sugar.  The grocer dropped
the coin in his pocket, but he put Roy's nickel in his drawer.  A
minute later an automobile driver came in.  The grocer said he owed him
a dollar and gave him the coin from his pocket.  That driver was the
same one I saw the other day."

"How do you know?" interrupted Captain Hardy.  "You didn't see him
to-day?"

"But Roy saw him.  He's a tall man with black hair and with a scar on
his left cheek.  That's the man I saw, and it's the man who drove up to
the house on the cliff the other day.  I knew that I had seen him, but
I couldn't remember just where."  For a moment he stood silent, fairly
panting with excitement.

"Well?" said Lew.  "What about him?  The grocer could owe him a dollar
as well as anybody."

"But he didn't owe him a dollar," cried Willie.  "Don't you see?  The
spy in the house below gave that dollar to the errand boy.  He gave it
to the grocer.  He gave it to the motor driver.  It's the same dollar.
He didn't put it in the till with the other coins.  He kept it in his
pocket separate.  That automobile driver is the man who carried the
messages to the wireless.  The messages are on the dollars."




CHAPTER IX

A FRESH START

Amazed, the members of the little patrol looked at one another silently.

"How could they send a message on a dollar?" demanded Lew at last.
"They'd have to engrave it, and then they'd never dare to use the
dollar again.  Besides, it would be too dangerous.  If the message were
on paper, the paper could be burned or chewed up and swallowed, and the
evidence of crime destroyed.  But they couldn't erase the engraving on
a dollar."

"I don't know how they do it," said Willie, "but I'm sure they write
their messages on those dollars."

"Willie is doubtless right," said Captain Hardy.  "We don't know how
they do it, but the evidence leads directly to the conclusion Willie
has come to.  The spy in the house below us writes his messages on
dollars and sends them through this grocer's boy and the motor-car
driver to the various secret wireless plants the Germans evidently
possess near New York.  I think that is plain.  And it indicates new
lines of action for us.  We must not only continue to listen in for
messages and watch this spy's nest, but we shall have to follow this
motor-car driver and also learn the secret of the dollars."

"Hurrah!" cried Roy, his eyes shining.  "Now there'll be something
doing."  Then he struck a tragic attitude and declaimed, "Little do the
treacherous hawks in yonder nest realize that the eagles of the law are
about to swoop down on them."

"Some orator, Roy," said Lew.  "If we're eagles, we must have wings.
Are mine sprouting yet?"  And he turned his back to Roy for the
latter's examination.

When the laughter ceased, their leader went on, "You boys are to be
congratulated for your discovery.  You have accomplished a great deal.
But what has been done is little compared with what remains to be done.
And so far you have worked in safety.  The work ahead may be very
dangerous.  The hidden wireless stations we are after are probably in
lonely places.  The men operating them are desperate fellows and will
not hesitate even to commit murder.  If one of you boys should follow
this motor driver into a lonesome spot and then be caught, you might
never return."

The smiles faded from the faces before him.  But the grave looks that
succeeded were not expressions of fear.  Rather they were looks of
determination--the same set marks of grim purpose that Captain Hardy
had seen on these same youthful faces when the wireless patrol was
stalking the desperate dynamiters at the Elk City reservoir.

Again it was Roy who brought back the smiles.  "If we have to follow
that automobile driver," he said, "it's a question of 'where do we go
from here, boys?'"

"Only the boy who does the following can answer that question,"
answered Captain Hardy.  "But there are several matters that we can
decide at once.  I think that we've determined pretty definitely that
the man in the house below us----"

"In the hawk's nest," interrupted Roy.

"Well, the man in the hawk's nest," continued their leader, smiling,
"is a German spy, that he is there to report the movements of our
transports, and that he does it by means of messages sent out on silver
dollars.  Now we've got to get hold of one of those dollars.  That
might not be a difficult task in itself.  We could hold up the grocer's
boy and take the dollar away from him, or we might get it away from him
by trickery and substitute another dollar for the stolen one.  We might
even be able to pick the grocer's pocket and give him a substitute
coin.  But neither plan would help us because the trick would soon be
discovered and the spies would know that they are suspected.  It
wouldn't do us any good to get their code if they knew we had it.  They
would simply use another.  What we must do is to locate their agents,
one after another, learn their codes and ciphers, and catch their
messages in the air.  When we have laid bare the entire scheme and
learned who their agents are, then the secret service can grab the
entire organization at once and end this treachery for good."

Captain Hardy paused and looked uneasily across the room, as though
lost in thought.  His companions were quiet as mice, each also busy
with his own thoughts.

"It's a long, hard task, boys," said the captain, after a time, and he
drew a deep breath, "a long task and, from now on, a dangerous task.
Whatever you do, boys, remember the Chief's warning.  Above all else,
we must be careful not to alarm the men we are watching."

As Captain Hardy rose to get his hat he said, "I don't quite see how we
are to follow this motor-car driver without being detected.  So I am
going over to Manhattan to see the agent the Chief has put in charge of
this investigation.  Perhaps I'll have some interesting news for you
when I return.  Meantime, keep your eyes and ears open and be careful."

With renewed interest and determination the members of the wireless
patrol returned to their posts.  But though they listened faithfully at
the wireless and uninterruptedly watched the hawk's nest on the cliff
below them, no alarming sound came out of the air and no suggestive
movement occurred within their vision.

Their captain came back with a smile of satisfaction on his face.  But
the members of the wireless patrol were too well disciplined to
question their leader.  They knew that, as always before, he would give
them the proper orders at the proper time; and that if they obeyed
those orders faithfully and intelligently, success would follow.  But
Captain Hardy was different in many respects from other commanders, and
his subordinates were not at all like ordinary privates in an army.
There was no question as to their loyalty, discretion, or intelligence;
and their leader believed he could attain the greatest success by
taking them into his confidence.  So presently he answered the question
that each boy was longing to ask.

From his pocket he produced detailed maps of all the neighboring
country, so mounted on cheese-cloth, after being cut into squares, that
they could be folded into small size without injuring the maps
themselves.  Thus the bearer could always follow his route, whether he
walked or rode, whether the air was calm or the wind blew fiercely, by
carrying in his hand the necessary map folded in small compass.

Now Captain Hardy spread out his maps full length on a table, and for
half an hour the little group bent over them, heads close together,
examining the topography of the city's environs as once they had
studied the city itself.  Marked to show altitudes, roads, byways,
rivers, streams, marshes, woodlands, and even the buildings themselves,
these maps enabled the little group of scouts to see, through their
imaginations, every foot of the country about New York.

They visualized the great, flat, low-lying stretches of southern Long
Island and New Jersey; the abrupt bluffs of Long Island's northern
coast by the shore of the Sound; the various watery arms that encircle
the American metropolis, permitting ships to sail in every direction;
the majestic Hudson leading straight north through a wonderful country
of rocks and hills, the impressive Palisades flanking its western bank
with their towering perpendicular walls of stone; and the rocky,
rolling country lying west of them, interspersed with streams and
swamps and woodlands and open fields and clustered villages.  And when
they had finished their study of the maps, they knew more about the
topography of the country they had studied, its roads and paths and
groves and elevations and other physical characteristics, than half the
people who lived in the region.  So they were prepared, if need be, to
find their way about with little difficulty.  And it was well they were
so prepared.  In the dangerous days to come they were to need all this
knowledge.

When they had studied the maps to their hearts' content--and each of
the four boys again and again examined them--Captain Hardy folded the
maps and thrust them into a waterproof cover.  They made a neat little
packet like a thin book.

"You will be interested to learn what the secret service has found
out," said Captain Hardy, as he stowed the maps in his pocket.  "When I
left here, I reported immediately to the man in charge of this
particular investigation.  Our discovery seems to me so important that
I ventured to ask why the secret service men didn't take the case up
themselves, as they would no doubt get along much faster than we
possibly can.  For it seems to me message sending ought to be stopped
at once.  The agent said that all this was true, but that the secret
service was so crowded with work it had to take up the most important
matters first."

"Most important matters!" cried Roy, in indignation.  "Doesn't the
secret service consider the guarding of our troops important?"

"Yes, Roy.  But whether the Germans know exactly when our ships leave
or not, their submarines will be waiting for them and our destroyers
will always be guarding the transports.  But here in New York German
spies are trying to create riots, to blow up buildings, to burn
factories.  They destroyed almost a million bushels of wheat in one
fire recently.  So you see that the secret service first must watch the
enemies that are trying to destroy our greatest city.  Our secret
service isn't one-quarter as large as it should be.  That is the fault
of Congress.  But meantime it is doing wonderful work, and it is a
great privilege to be able to assist in that work."

"But what have they found out about this job?" demanded Roy.

"You're like a hound on a keen scent, Roy," said their leader.
"Nothing ever takes you away from your objective.  Well, this is what
they've found.  It seems that they have been keeping a record of the
grocer's telephone messages, as well as those from the 'hawk's nest'
down below.  Every time transports sail, some one in Hoboken calls up
this grocer and says, 'I have some sugar on the way.  Do you want any?'
And the grocer replies, 'Yes.  How many barrels can you let me have?'
And the man in Hoboken gives the number.  That number corresponds with
the number of transports about to sail.  So you see how the grocer
knows when to send his boy for the wireless messages.  But before he
sends him, he always telephones to the 'hawk's nest' and says, 'I have
some sugar coming and can let you have five pounds to-day.  Do you want
it?'  And the number of pounds he offers is the same as the number of
ships that are to sail.  So the spy below us knows what to look for.
And I suppose the man in Hoboken also telephones the automobile driver
when to come for the dollars."

"Who is this man in Hoboken that does the telephoning?" demanded Roy,
when Captain Hardy had done speaking.

"Ah!  That they don't know.  He has always called up from a different
place and has gotten away before the secret service could spot him.
But the agent assures me that they'll have him soon.  He always
telephones from a station close to the piers where the transports load.
The next time he calls for the grocer, the telephone operator is going
to delay him while she notifies a secret service agent posted near by
with a motor-cycle.  So they'll spot him and trail him.

"And that reminds me," continued Captain Hardy, after a pause, "that
we're to do a little motor-cycle work ourselves, and that Henry has
been selected for the job because he is familiar with motor-cycles."

Henry's eyes lighted with pleasure.  Not only was he the oldest boy in
the wireless patrol, and Captain Hardy's first lieutenant, but he was
one of those natural mechanics who seem to know instinctively how to
handle tools and make things.  Indeed he had constructed his own
wireless outfit and shown his fellows how to make theirs; and he could
repair a motor-cycle almost as skilfully as a garage man.  So it was
natural that he should be selected for this task.

But there was still another reason why his captain had chosen him for
the work he had in mind.  Though not so quick or clever as Roy, Henry
was a keen observer and close reasoner.  Moreover, he was entirely
dependable, was very discreet, and being the largest boy in the party,
was best fitted to take care of himself if he got into trouble.

"We are going to trail this automobile driver with a motor-cycle, as
you have probably guessed," explained Captain Hardy to the little group
of scouts.  "And Henry is to do the trailing.  Come, Henry.  We'll go
take a look at your machine.  The secret service people said that it
would be here in half an hour."

"Where?  In this house?" asked Roy eagerly.

"No, not here, but at a house around the corner from the grocer's.  It
will always be in readiness for instant use."

As Henry put on his hat and followed his leader, the other scouts
looked at him somewhat enviously.  "Remember," said their leader,
turning about, "each one of you has his work to do, just as Henry has.
See that you do it."

At once the boys returned to their posts, while Henry and his captain
passed out of the house and went down the street.  Instead of going
directly to their destination, the two made their way by a roundabout
route and kept a sharp lookout lest they should meet the grocer or his
boy.  But they passed almost no one and came soon to a little white
house, not far from the grocer's store, that was set back in a yard
behind a high hedge.  Connected with the house was a small garage,
built so as to resemble an extension of the dwelling.

A keen-eyed woman answered their knock at the door and looked at them
questioningly.

"We are the sugar refiners sent by the Federal Sugar Company," said
Captain Hardy, repeating the words given him by the secret service
agent.

"I've been looking for you," replied the woman.  "Come in."  And she
led them at once through the house to the garage.

Henry was about to ask Captain Hardy what he meant by saying that they
were sugar refiners, but when he saw the motor-cycle that awaited him
he forgot his question and gave a sharp cry of exultation.  It was a
beautiful machine, with tires so strong and thick they were practically
puncture proof and were evidently equal to any demand that was likely
to be made upon them.  Evidently the engine was one of great power.
The frame of the machine was a dark gray; and Henry instantly noted the
fact that there was an almost utter absence of nickel about the
motorcycle.  The spokes, handle-bars, and trimmings were all enameled
black.  The headlight was a powerful electric one, with a black cap
over the lens.  With great interest Henry examined the spark- and
gasoline-controls, the motor itself, and finally the muffler, which was
of the most improved variety.  He looked in the gasoline-tank and found
it full.  The oil-tank was brimming.  Every moving part had been
carefully greased and cleaned.

"What's this?" cried Henry, of a sudden, noting what seemed to be an
extra and unnecessary piece of framework.

"Take it out and see," said Captain Hardy, with a smile.

Carefully Henry examined the fastenings, to see how the extra tubing
was adjusted.  Then he drew it forth.

"A metal cane," he said, puzzled.  "What is it?  What is it for?"

Captain Hardy explained.  Then he picked up a small electric torch,
some well insulated wires that lay coiled on a near-by chair, and
something that looked like a giant fountain pen.  He handed these
articles to Henry, and repeated what the secret service man had told
him as to their use.

"Put them in your pocket and be very careful that you do not lose
them," directed Captain Hardy.  "Carry them with you so that you can
run to your motor-cycle at a second's notice.  Now replace that cane on
the machine."

Henry slid the cane back and fastened it in place.  It was gray, like
the car, and seemed to be a part of it.  Then Captain Hardy fastened
the little map case above the gasoline-tank in such a way that Henry
could pluck out a map as he rode.

"Now," he said, "there is nothing to do but wait until the automobile
driver comes for another dollar.  Then you must follow him wherever he
goes.  You must watch every movement he makes.  But you must not let
him see you.  It's a hard thing to ask of you, Henry, for everything
hinges upon your success."

A look of determination flashed in Henry's eyes.  "I'll do my best," he
said simply.

"I know you will," rejoined his leader.  Then he added, with a smile,
"Now we'll go back to the eagle's nest and wait for the hawk to appear."




CHAPTER X

THE PURSUIT IN THE DARK

Day followed day but that bird of prey did not appear.  "A watched pot
never boils," said Henry at last, trying to conquer his impatience; and
he turned his mind from the task of following the automobile driver to
the even more difficult task of securing one of the dollars.  For
sooner or later the wireless patrol would have to procure one of these
mysterious coins.  But Henry could see no way to accomplish that end
without alarming the quarry.  Day after day the little patrol discussed
the question.  It was useless to think of securing a coin from the man
on the cliff, from the grocer's boy, or from the grocer himself; for
none of the three had possession of the coins very long after they were
marked.  And what became of the coins after they left the grocer's
hands could as yet be only guessed at.

Again and again, as the days passed, the members of the wireless patrol
discussed the secret of the dollars, but nowhere could they find even
the suggestion of a solution.  Slowly time dragged on.  Day followed
day.  The watch grew monotonous and tiresome.  There were no signs of
hostile activity in the hawk's nest and the secret service had no
suspicious telephone conversations to report.  It required all their
resolution to keep the young scouts at their task of listening in.
They even began to think that they had been detected and that the
activities of the spy in the hawk's nest were ended.

Then, one afternoon, galvanizing them to sudden action, came a cryptic
message from the secret service, announcing that the Federal Sugar
Company could use experienced refiners at once.  Henry took the
message, and recalling what Captain Hardy had told the woman when they
went to see the motor-cycle, at once guessed its meaning.  He ran to
Captain Hardy and repeated it.

"You guessed rightly," said Captain Hardy.  "Hereafter we, too, have to
use code messages, and we just carried out the spy idea about sugar.
This message is to warn us that transports are sailing.  Go to your
stations, boys."

Lew flew back to the wireless.  Roy and Willie hustled down to the pine
grove.  Henry, his heart beating fast, hurried away to his motorcycle
station.

For a long, long time nothing happened.  Then a line of transports came
into view.  Presently the spy appeared at his window, sweeping the
channel with his powerful glasses.  For several moments he studied the
passing ships carefully, then withdrew from the window and was lost to
sight.  In a very few moments the scouts saw the grocer's boy, with his
basket and a few small packages, enter the house, then hurry away.  Roy
trailed him directly to the grocery store, but did not enter.

Henry, meantime, impatient, like Paul Revere, "to mount and ride,"
stood peering out of a tiny window of the garage, awaiting the expected
motor-car.  In his eagerness minutes seemed like hours.  As time passed
and no motorcar came, he began to believe that none would come, that
the spies had learned of the trap set for them, and that they had
discontinued their work or devised some new plan of operation.  So
impatient did Henry become that he could hardly refrain from running
into the street to see if any motor-cars were approaching.  At last his
anxiety was relieved.  He heard the regular beating of a motor climbing
the hill.  Then as he glued his eye to the tiny window the familiar
car, a powerful roadster, with its top raised, rolled by.  Again Henry
tried to catch the number and failed.  Then he knew that the
dust-covered license number was not dust covered by accident.  Quickly
he noted the treads of the tires, and the shape of the wheel hubs,
axles, and springs, so that he could identify the car.  Then it passed
from his sight.

And now his anxiety suddenly grew a hundredfold.  Always before, the
car had returned the way it came.  Suppose that this time it should go
back by another route and he should miss it.  He could not endure the
thought.  Quickly he opened the door and peered forth.  The driver was
just turning his car, as he had always done before.  The matter was
settled.  He would pass Henry's hiding place on his return.  Quickly
Henry shut the door and waited with what patience he could command.

for what seemed like an hour he waited.  His pulse beat fast with
excitement.  He could hardly compel himself to stand quietly by his
window and wait.  The old fear that the motorist had gone away by some
other route returned and began to torture him.  He wanted to run out
into the street and assure himself that the car was still in sight.
And then, when it seemed he could endure the suspense not a second
longer, he heard the purring of a motor, and the car he was waiting for
slid quietly by and began to descend the hill toward the ferry.

At once a new fear sprang up in Henry's heart.  Suppose the motor-cycle
wouldn't go.  Suppose he should be so slow as to miss the ferry-boat.
Desperately he flung open the door and trundled his motor-cycle out to
the street.  The roadster was only a block ahead of him.  Speedily
Henry pushed the cycle along the road.  The motor began to bark and
Henry leaped to the saddle.  In another instant he was speeding after
the roadster and was already so near it that he had to jam on his brake
to avoid coming up to it.  Near the ferry there was more traffic and
Henry felt relieved.  He dropped back a little distance and was almost
completely hidden from the roadster by the carts and cars between them.
So they proceeded to the ferry, the suspected driver bringing his
roadster to a halt near the front of the ferry-boat just as Henry,
following a string of wagons and carts, reached the other end of the
craft.  Then the whistle blew and the boat pulled out into the Bay.

But Henry had now no eyes for the sights in the harbor that had
formerly so fascinated him.  His entire attention was centred on the
roadster.  The driver of the roadster remained in his seat, calmly
looking out over the Bay.  Henry stood his machine against a post and
sought a position near by where he was sheltered from the spy's
observation by a huge coal truck, but where he could himself distinctly
see the roadster by peering through the spokes of the truck wheels.
Again he made a mental inventory of the distinguishing features of the
car he was following.  And before the ferry-boat reached Manhattan he
could have passed a perfect examination as to the appearance of the
roadster.

It was already dusk when the boat slid into its slip, and the heavy
clouds overhead gave promise of a dark night.  Henry was thankful.  Up
Broadway he followed the roadster at a safe distance, then up Park Row,
and so to the Brooklyn Bridge.  Across this magic structure, one
hundred and fifty feet above the surface of the water, Henry continued
to follow the roadster.  The great buildings, piled skyward in huge
masses, were twinkling with a million lights.  Boats were coming and
going on the stream below.  Electric cars followed one another across
the bridge in endless procession.  Elevated railway trains thundered
past unceasingly.  Up-stream shone the fairy lights of the other
bridges that span the East River.  The Navy Yard lay in full view.  But
the scene that at other times Henry would have found entrancing, now he
scarcely noticed.  He had eyes for one thing only--the rolling
motor-car ahead of him and the red eye that now glowed at its rear.

He turned on his light and at a safe distance followed the roadster,
which was heading due east.  They passed the business portions of
Brooklyn.  They left Prospect Park behind them.  They traversed a
region of apartment-houses.  Then came less thickly settled districts,
with block after block of private residences, each in its own little
yard.  And so they proceeded to the very outskirts of the city, where
houses gave place to vacant lots and vacant lots were succeeded by open
fields.  Darkness had come.  Traffic had grown less and less.  Now
there were no sheltering vehicles between himself and the roadster.  A
great fear of discovery sprang up in Henry's heart.  He switched off
his light, risking arrest, and rode on in the darkness.  Occasionally
he passed under a lone street lamp.  And now he understood why his
machine was enameled black instead of being nickel finished.  It gave
back no answering gleam when beams of light fell upon it.  It was made
for just the secret sort of work it was doing now.  For, with his motor
completely muffled, his lamp extinguished, Henry was now riding through
the night like a dark shadow.

Long before this, Henry had slipped the proper map from its case and
had followed his route as far as he was able to see.  Though his eyes
could no longer pierce the darkness, Henry knew that he was passing
through a lonely, undeveloped section of land.  Dimly he glimpsed tiny
bits of woodland here and there.  The lonely lights Henry occasionally
saw were the lamps in isolated farmhouses.  He could no longer tell
exactly where he was, though he knew the road he was following.  But he
had watched his speedometer closely and he knew he was traveling about
twenty miles an hour.  He was keeping pace with the motor-car, but
riding several hundred yards behind it.  So they continued for a long
time.

Suddenly the motor-car swung round a curve and vanished from sight.
Henry knew the car had rounded a curve because he saw the lights swing.
A minute later as he was about to reach the curve himself, he heard the
rapid beating of hoofs and a team of horses came tearing round the bend
and charged straight at him.  Evidently the driver had lost control of
them and it flashed into Henry's mind that they had been frightened by
the roadster ahead.  But he had no time to think of anything.  The
frantic animals bore down on him like an express-train.  Quick as
thought Henry turned sharply to the right and threw on his power.  The
horses were almost upon him.  The driver glimpsed him, cursed him
savagely for having no light, and gave a powerful heave on the reins.
The horses swerved in one direction as Henry shot in the other, missing
them by less than a foot.  Before he could straighten his machine
again, it had left the road and was plunging over the rough surface of
a field.

Henry jammed his brake on so suddenly that it toppled him from the
saddle, but neither he nor the machine was injured.  He turned the
motor-cycle about and headed for the road.  And now his hair almost
stood on end.  In the darkness he could dimly see some great lumber
piles, as large as houses.  He had all but crashed into them at high
speed.  Now he understood why the roadster's light had disappeared when
the car turned the curve.  It had been hidden by these great lumber
piles.  Rapidly Henry ran back to the road.  He knew the motor-car
would now be far ahead of him.  He should have to hasten to overtake
it.  He ran along the highway, pushing his machine, and leaped to the
saddle when the engine began to explode regularly.  Then he turned the
curve and peered ahead into the darkness.  The road seemed to lie
straight before him, but the motor-car had utterly vanished.

For a moment Henry rode on, almost bewildered.  Then he looked rapidly
about him.  No farmhouse was in sight to which the motorcar might have
gone.  No light gleamed anywhere.  But he could dimly see trees here
and there.  And he made out a wooden fence lining the left side of the
road.

"Lucky I didn't shoot in that direction when I met that team," muttered
Henry.  "I'd have gone clear through that fence."  He dismounted, set
his machine up, and took out his pocket torch.  Holding it close to the
road, he began to examine the highway.  "There are the marks of his
rear tires," he muttered.

And thankful indeed was the puzzled scout that he had learned so well
at Camp Brady to observe carefully.  He mounted his wheel and rode a
few hundred yards further.  Then he examined the road again.  He found
the tracks he was searching for.  He rode on and dismounting, found in
two places the telltale marks.  But the third time he examined the
highway there were no marks of the roadster's tires visible.

"He left the road between this point and the last stop," murmured Henry.

He went back a hundred feet and searched.  There were no tire marks.
Another hundred feet showed no prints in the dust.  But the third
hundred revealed the wheel marks.  "Ah!" said Henry, "he turned off
close by."

He set his wheel against the fence and went forward, following the
prints with his light, which he shaded carefully and held close to the
road.  Within fifty feet the marks turned straight off to the left.
The car had passed from the highway through a gap in the fence, into an
open field.  What the field was like Henry could only conjecture.  He
dared not flash his light around to see.

He ran back and got his machine, then followed the wheel prints into
the field.  They did not show readily on the grassy surface, and soon
he had lost them altogether.  At first a sense of fear clutched at his
heart.  He recalled his leader's words as to the dangerous nature of
this duty.  Here he was in exactly the lonely situation his captain had
foreseen, by himself, and with no means of defense.  The enemy he was
trailing had disappeared.  He might be a mile distant or he might be
waiting for his pursuer, behind the nearest tree.  Henry shivered with
fear and stood irresolute.  But the feeling passed when he realized
that he had lost the trail, that his quarry had escaped him, that he
had failed his captain.  A wave of remorse swept over him.  The sense
of fear left him entirely, and he bent all his energies to the task of
finding the motor-car.  He hid his wheel in a thicket that he might
work faster, pausing only to snatch from it the metal cane fastened to
the frame.

Cautiously he glided forward, crouching as he moved, and taking
advantage of every rock and bush he could see to screen himself.  He
held his breath and listened.  Now he crept forward a foot at a time.
Now he advanced swiftly for yards.  He worked his way to the right and
the left.  But nowhere could he see what he was searching for, and no
betraying sound came out of the thick blackness.

"It's no use," he said to himself bitterly, after he had searched for a
quarter of an hour.  "I have lost him, and if I am not careful I'll
lose his message as well."

Near by he could dimly discern a tall stump.  He ran over to it and on
it laid his map, a pencil, his electric torch, his knife, the wires
that he had been carrying in his pocket, and the giant fountain pen.
Grasping the tip of his cane he gave a sharp tug and an inner lining
slid outward.  From this he drew out a third length, and from that a
fourth.  His metal cane was in reality an extension rod, not unlike a
telescoping fishing-rod.  It was fully ten feet long.  In its curved
handle was a small opening, like a keyhole.  Into this Henry jammed the
bayonet connection that terminated one of the wires.  The other end of
the wire he thrust into a like opening in the side of his big fountain
pen.  Into the opposite side of his pen he fastened one end of his
second wire, attaching the other end of this wire to his knife, which
he thrust deep into the earth.  Then, raising the extended cane aloft
with his left hand, he put the point of his fountain pen to his right
ear and listened.  The mysterious articles that the secret service had
supplied constituted a complete wireless receiving set.  He could catch
any message sent from a point within six or eight miles.

He was not a moment too soon.  Hardly had he gotten the fountain pen
adjusted before there came a crackling in his ear.  He rested his cane,
upright, against the stump, and began to tune his instrument by sliding
the cap of the fountain pen in and out.  In a second he had tuned it
perfectly.  The sounds came to him with startling clearness.

"He's near at hand," muttered Henry.

He seized his pencil and wrote down on his map the letters that were
sounding in his ear.  Then with frantic haste he disconnected his
instrument, telescoped his extension cane, and gathered up the
different articles and thrust them into his pockets.  As rapidly as he
could pick his way, he went back to his hidden machine.  He fastened
the metal cane in place, and got everything ready for a quick start.

Suddenly a faint purring noise came to his ears.  "Ah!" muttered Henry,
"he's started his motor.  He's off in that direction.  What shall I do?"

His first impulse was to run at speed toward the purring motor, and to
try to locate exactly the position of the hidden wireless station.  But
discretion showed him that was not wise.  The spy might turn his lights
on at any moment and Henry would be caught.  Then everything was lost.

"I must make sure I can find the place in the daytime," muttered Henry.
Carefully he gauged the sound, deciding whence it came.  "He's right
off there," he said.  And with his heel he made a long mark in the
turf, pointing straight toward the sound.

Almost before he finished, the sound grew louder and Henry knew the car
was advancing.  He shrank back into the thicket, dragging his
motor-cycle with him.  An instant later the roadster rolled softly
past, not more than fifty feet distant.  In a moment more the car had
reached the fence and turned into the highway.  Its lights suddenly
flashed out and the car went bowling down the road toward Brooklyn.

Henry leaped from the thicket and ran toward the highway, pushing his
motor-cycle before him.  He paused at the opening in the fence, and
with his knife smoothed a space on one of the posts and marked a cross
on it with his pencil.  Then he ran to the highway, started his motor,
and was soon flying down the road in pursuit of the roadster.  And as
he had come, so he returned, with lights out, until Brooklyn was
reached and the streets were once more alive with traffic.

At a safe distance he followed the unsuspecting motorist and saw him
turn into a private yard in Flatbush.  Instantly Henry dismounted,
thrust his wheel behind a hedge that fenced a private residence, and
gained a position where he could watch the spy's house.  He saw the spy
close and lock his garage and enter the house.  Stealthily Henry
approached and noted the house number.  At the corner he got the name
of the street.  Then he hurried back to his hidden motor-cycle and was
soon flying back to his comrades at the eagle's nest.




CHAPTER XI

AN UNSUCCESSFUL SEARCH

It was characteristic of Henry that he should tell the worst about
himself first.  In his own manly way he was willing to accept the blame
for his failure.

"He got away from me," he began, so chagrined that he could hardly
repress the tears.  "I didn't find the hidden wireless and I have
failed in my task."

Before his captain he stood with downcast eyes and tortured heart.  His
experience at Camp Brady had taught him that the wireless patrol
expected every member to do his duty--and he had failed.

Captain Hardy looked at his lieutenant for a moment without answering.
He had not the slightest idea of what had occurred, but he recognized
instantly the manliness of Henry's report.  The latter was offering no
excuses, making no attempt to shield himself from the consequences of
his failure.

"Suppose you tell us just what happened," said the leader gently, "and
we can judge better how badly you have failed."

Gratefully Henry looked up.  He had not expected a scolding.  That was
not Captain Hardy's way of disciplining his boys.  But he had felt sure
his leader would show how deeply he was disappointed, for Captain Hardy
was terribly in earnest in this quest for spies.  So once again Henry's
heart went out to his captain.  Rapidly he related what had befallen
him.  As he proceeded with his story, his leader's face lost its look
of grave concern, his eyes began to flash with interest, his cheeks to
burn with eagerness.  When Henry's narrative had reached the point
where the motor-car had disappeared in the field and Henry was
searching for it.  Captain Hardy held up his hand.

"Stop a moment," he interrupted.  "You were in no wise to blame for
what happened, and instead of being condemned for failure you are to be
commended for your success.  Many a boy would never have found where
that car went.  And even though you did not learn exactly where the car
was, you have located the field and you may be sure that driver never
went very far in a field.  We shall find the place easily enough.  Go
on."

Henry looked at his leader gratefully and a happy light came into his
eyes.  "Do you really think I didn't fail?" he asked eagerly.

"Assuredly," insisted Captain Hardy.  "I think that you have learned
enough to enable us to locate this hidden station.  Go on."

Henry proceeded with the story of his search in the dark, of his
uncertainty as to what he should do, of his fear of missing the message
as well as the car, and of how he had intercepted that message, marked
the fence post, and located the home of the automobile driver.

"Why, Henry," cried Captain Hardy, when the recital was ended,
"whatever put it into your head that you had failed?  You have done
well--exceedingly well."

"But I didn't find the hidden station, and you said that was so
important."

"That is a mere detail, Henry.  We shall find it easily enough.  We
have our experience at Elk City to direct us."

"That's just why I felt so bad," said Henry.  "If these Germans have
concealed their wireless plant as skilfully as the dynamiters did at
Elk City, we may never find where it is."

"We'll try before we give up hope," said the captain smiling.  "And
even if we never find it, we now know something more important than the
location of one of their several wireless plants.  We know where
another member of the gang lives.  That is excellent, Henry, excellent!
The Chief will be more than pleased.  I know he is a great deal more
concerned about this wireless situation than he permits us to think.
The public is clamoring for protection for the troops and the Chief
simply cannot accomplish one-fourth of what is demanded of him.  If we
uncover this gang for him, we shall do a very real service to America,
boys."

"We'll do it," cried Willie vehemently.  "We'll do it.  We'll get 'em
just as sure as we got the dynamiters."

"I believe we shall," smiled the captain.  "And if that's the way you
all feel about it, I know we shall.  We're closing in on them fast.
To-morrow we'll go out to that field Henry has marked and see what we
can find in the daylight."

So it happened that the succeeding forenoon found the five members of
the wireless patrol rolling rapidly toward the point of investigation,
in a motor-car furnished by the secret service and driven by one of its
agents.  Henry sat beside the driver and pointed out the way, while the
others crowded into the rear of the car.

With his map on his knees Henry traced the way.  Speedily they passed
through the built-up portion of Brooklyn and came shortly to the
sparsely settled district through which their road ran.  Henry scanned
the way with curious interest.  He had been over the road but he knew
nothing of what he had passed.  Occasionally they whirled by a tree
close to the road that Henry thought he had glimpsed in the darkness.
So they flew forward until Henry, looking eagerly ahead, cried out,
"There are the lumber piles."

The driver slowed his car almost to a walk and they looked in the dust
for telltale marks.  Few teams had passed since Henry's adventure, and
in the dust could still plainly be seen the marks of Henry's wheel as
he had turned sharply into the field, and the narrow tracks of the
vehicle that had almost run him down.

But Henry was more interested in marks of another sort.  "There!" he
cried suddenly.  "See those tracks?  They're the marks of the spy's
roadster."  And he pointed to parallel tread marks, one made by a chain
tread tire and one by a diamond tread.

They passed on.  Not many hundred yards distant was an opening in the
fence.  "That's the place he turned off," insisted Henry.  "See that
light place where I shaved the post?"

But they did not turn into the field.  Instead the motor-car continued
steadily on its way.  A half mile up the highway was a road-house known
to the driver.

"It's about eleven o'clock now," said the secret service man.  "We'll
have luncheon at the roadhouse and in the meantime we can stroll around
and hunt up this wireless plant.  We'd attract too much attention if we
drove directly into the field."

They stopped at the road-house, ordered luncheon, and said they would
stroll about until noon.  Then they wandered, apparently aimlessly,
about the place and into the fields.  The country was nearly level,
with slight depressions here and little hillocks there, and bits of
woodland all about.  The road-house was the only structure in sight,
and when they had passed beyond a slight elevation, even this was
hidden.  Apparently there was not a soul in the neighborhood.  They
paused just inside a little grove and made sure that no one was
following them from the road-house.  Then they pushed rapidly on into
the little thicket which Henry recognized as his hiding-place of the
previous night.

After a moment's search, Henry found the mark he had made in the turf.
"The motor-car was in that direction," he explained, pointing along his
turf mark.

His fellows looked in the direction of his outstretched arm.  At a
distance of a quarter of a mile was a thick little grove.  Henry was
pointing straight at the heart of it.

The scouts had kept themselves well hidden in the thicket as Henry was
finding his mark.  If any one was in the wood, that person could not as
yet see them.

"I have no doubt we shall find the secret station in that grove," said
Captain Hardy.  "I see several tall trees sticking up above the others
that might conceal aerials.  I doubt if any one is there now, but some
one might be.  So we shall have to approach carefully and in such a way
that we can capture any one who might be within the grove.  Suppose we
advance on it from all four sides, as we did on the willow copse at the
Elk City reservoir.  Then if any one is within the grove we shall see
him."

The leader gave each boy his orders and the advance began.  Henry was
to circle and enter the woods from the rear.  Roy was to approach from
one side and Willie from the other.  Lew was to go in at the front.
Captain Hardy and the secret service man were to station themselves
outside the wood so that they could see every point of its exterior and
detect any one leaving it.  Each glided away toward his post.

At a given signal from Captain Hardy, the boys began to work their way
silently from their posts into the grove.  This was small in extent and
such precautions seemed almost unnecessary.  But after their desperate
experience with the dynamiters, the members of the wireless patrol were
taking no chances.  They knew full well that discretion is the better
part of valor.  And they knew, in addition, that the success of their
search might depend upon the caution with which they proceeded.  So
they went forward, when the captain's signal rang out, like so many
Indians on the war-path, stalking a hated enemy.

Indeed they were almost as invisible as Indians.  Each had circled
skilfully to his post.  And now each crept forward silently, slipping
from rock to bush, taking advantage of the slightest cover, and
advancing so stealthily through the tall grass that even the two men on
watch outside the grove could hardly tell where the scouts were moving.
And any one inside the grove could not have detected them at all.

The four scouts reached the four sides of the grove almost
simultaneously.  Each of the four crept round the trunk of a big tree
and squatted down with the trunk at his back, to look and to listen.
From side to side their eyes roved, examining every tree and stump in
sight.  But they saw nothing on the ground or in the branches overhead
to alarm them.  There was no indication of human presence other than
their own; and Willie was certain that the wood was deserted, for
several small flocks of birds flew up in alarm as he penetrated the
grove.  Had other men been within the wood, he knew the birds would
long ago have been frightened away.

Slowly the four scouts worked their way toward the centre of the grove,
gliding round the trunks of trees and stopping every few feet to look
and listen.  But they heard nothing, saw nothing, to indicate that any
man was within the grove.  Each one, as he advanced, scouted to right
and left of his line of march, so that when the four met in the centre
of the wood, they had covered every rod of ground within the grove.
And they had found nobody.

What was more, they had seen no signs of a wireless outfit.  But, in
view of their experience in searching for the dynamiters' hidden
wireless, this was not surprising.  None of the scouts had expected to
find the secret plant without a thorough search.  As soon as Captain
Hardy and the secret service man joined them, a systematic search of
the wood was begun.

There could not have been more than two hundred trees in the little
grove.  Satisfied that the place contained no enemy agents, Captain
Hardy took his company to one end of the ground and began a careful
examination of each tree.  The six searchers strung out in a line
across the grove, testing each tree as they advanced.  They scanned the
trunks and thumped them with clubs to make sure that they were not
hollow.  They peered at them from all sides, looking for holes and
hollow limbs.  With sticks they scratched away the leaves from about
the bases of the trees, turning up the soil for several inches and
testing it for hidden wires.  All the trees seemed sound.  No hollow
limbs were discovered.  No suspicious marks were found in the earth
about the tree trunks.  The tall trees noted by Captain Hardy seemed
never to have been touched by man.  From tree to tree the search
proceeded until every tree in the grove had been tested and the scouts
were on the far edge of the wood.  But no hidden wire, no secret
instruments, no skilfully concealed aerials were found.

Blankly the searchers looked at one another.  "It must be here," said
Henry.  "I am absolutely certain that the motor-car came from this
direction and was about this distance from where I stood.  And the
signals were so loud and clear that I'm just sure they were sent from
some spot close by."

"Let us look for wheel tracks," suggested Captain Hardy.  "If we can
find where the car stopped, we shall know that the message was sent
from some point near by.  Search along the sides of the grove first."

The party divided, and three searchers examined the ground along each
side of the grove.  Walking abreast and several feet distant from one
another, they covered a broad strip of ground.  Twice each party
retraced its tracks but found nothing.

"Try another strip, farther away from the grove," said Captain Hardy.

Again the searchers lined up and went slowly forward on either side of
the woods.  Bending low, stepping slowly, sometimes kneeling to examine
a suspicious mark, they moved carefully on.  The thick turf had taken
no telltale imprint.

"I fear it's useless," sighed the leader.

"Let's try again," pleaded Willie.  "The car was here.  We know that.
And somewhere it was bound to make a mark.  It might have gone beyond
the grove."

They made another search, this time extending their examination to the
land beyond the wood.  Suddenly Roy gave a cry.  "Here it is," he
called.

The others ran to him.  And there, sure enough, in a little bare spot
between two hummocks of grass, was the plain imprint of a diamond
tread.  Instantly Roy and Willie dropped to their knees and began to
feel along the line of the tire mark.

Henry and Lew, meantime, searched to right and left of them.  "Here's
his other wheel track," suddenly cried Lew, and there, sure enough, was
a distinct impression of a chain tread tire.

They proceeded in the direction in which the car had been moving.
"Here's where he turned," cried Henry.

The turf before him was torn and ragged.  Distinctly they could see the
impression made by the driving wheels as they gripped the ground in
starting.

"Then here is where he stood," said Captain Hardy.  "It is immediately
behind the wood.  Your mark pointed straight enough, Henry, but your
man was farther away than you thought.  Probably he ran behind this
grove to make doubly sure he would not be seen from the highway.  The
hidden station must be in this end of the grove.  We'll search again."

Once more they plunged into the wood.  Again they examined every tree.
Up one trunk after another shinned Roy and Lew, who were born climbers.
But hunt as they would, search as they might, they found nothing to
indicate a secret wireless.  At last, completely baffled, they gave up
the search.

"It's here," insisted Captain Hardy.  "Our experience at the Elk City
reservoir makes me sure of that.  They're too clever for us.  But we'll
get them yet.  We'll follow that roadster so closely next time that we
can't miss the secret.  It's too bad, boys, but don't be discouraged.
We have done much to come so close.  Now we'll go back to the
road-house.  It's long past time for luncheon."




CHAPTER XII

ANOTHER OBSTACLE

Time wore on.  Now that there was something definite to work on, the
secret service began to take a more active part in the spy hunt.

"You have helped us greatly," said the Chief to Captain Hardy, one day.
"My men were so rushed with work that they simply could not take the
time to go hunting round for clues.  But now that the wireless patrol
has furnished those clues, we shall be able to follow them up.  But we
want you to continue at work just the same.  You can still help us."

But the members of the wireless patrol, and especially Henry, found
small satisfaction in the Chief's praise.  They had not come to New
York merely to furnish the secret service with clues.  They had come to
uncover the system by which spies were betraying the movements of our
transports.  At the Elk City reservoir they had succeeded where trained
men had failed; and they meant to succeed here also.  They felt that
the Chief was patting them on the head, as it were, and telling them
that they were good little boys.  They meant to show him they were the
equals of his own men, even if the Chief's words, instead of pleasing
them, stimulated them to half angry activity.

"He needn't think that just because we're boys and come from the
country we aren't any good," argued Roy.  "That's the way everybody
talks about boys.  That's the way they talked about us at Elk City
until we caught the dynamiters and showed them what we could do.  We'll
show Uncle Sam's men, too.  I don't care if they are famous detectives.
We'll get these fellows ourselves.  We're not going to have the secret
service step in now and take all the credit."

But it was one thing to talk so confidently and quite another to
accomplish the end they were striving for.  They had not yet discovered
a single one of the hidden wireless stations, and the secret of the
dollar was still a secret.  As far as the members of the wireless
patrol could see, it was likely to remain a secret.  How they could
secure one of the dollars without being detected, they did not know;
and how they were to read the message, even if they did get the dollar,
was more than they could see; for by this time they had dropped the
idea that the messages were engraved on the coins.  More and more those
dollars appeared a great and insuperable obstacle.

"Couldn't we manage to see the spy when he marks those dollars?" asked
Roy.  "Is there any way that we could get into his house and hide, so
as to watch him?"

"You mustn't think of trying," said Captain Hardy decisively.  "But
possibly you could find a new place to watch from that would enable you
to see him better.  These field-glasses of mine are very powerful, and
if you can find the proper view-point, you can see him well, even from
a distance."

Without a word Roy grabbed his hat and darted out of the house.  A
second later he was slipping through the thicket on the sloping
hillside.  Cautiously he crawled from one point to another.  The only
station that gave any promise of success was the pine grove originally
selected.  The tree from which they had been watching the spy's house
was a giant pine that towered above every other tree in the grove.  But
the scouts had never dared to ascend beyond the protecting foliage of
the other trees, lest they be detected.  So they had been looking
upward at an angle, as they watched the spy's house.  Roy now saw that
if he were to climb high up in the big pine, he would be on a level
with the spy's windows, and could doubtless see clearly into the house.
The difficulty would be to make the climb without being detected.

Roy made his way back to headquarters and reported on his observations.
"I didn't go up," he said, "for fear he would see me."

"You were wise," replied Captain Hardy.  "We must devise some plan by
which you can get up the tree unnoticed."

"Camouflage!" said Willie suddenly.  "Fix one of us up like a pine
tree.  Then he won't see us."

"Just the idea," said Lew laughing.

"We'll have to use the smallest boy in the bunch," said Captain Hardy,
"and that's you, Willie.  Come.  We'll see what we can do with you.  Go
get me some samples of pine bark and needles."

Willie speedily got the desired objects.  Captain Hardy examined them
critically.  "You ought to have a dark brown suit, painted with
irregular stripes, like branches, and dabs of green, like foliage."

"Don't forget his face," cried Roy in glee.  "That will have to be
painted brown and green also."

A laugh went up.  "I'm merely telling what ought to be done, Willie,"
said Captain Hardy reassuringly, "not what we shall do.  We have to
guard against observation by persons other than this spy.  If the
neighbors saw a boy going out of here garbed the way you want Willie
fixed up, Roy, they would begin to ask questions.  And we don't know
what the spy's relations are with his neighbors.  What we shall have to
do is to dress Willie in clothes as nearly the color of the tree as
possible.  We can get shoes, stockings, and a suit of clothes to match
the tree trunk.  We can get a cap the shade of these pine-needles.
That leaves hands and face.  They, too, must be disguised.  A pair of
gloves of the proper shade will take care of the hands.  But what about
the face?"

"Nothing for it but to paint it," said Roy, his eyes dancing.

"I guess you're right," said Captain Hardy.  Willie made a wry face.
The captain saw him.  "The trench raiders blacken both their hands and
faces when they steal out into No Man's Land at night," he said.  "But
we won't use real paint, Willie.  We'll get some theatrical paint that
comes off easily.  I'll get the necessary materials at once."

He noted down the sizes needed and went out.  And it was well he acted
so promptly.  That very afternoon a message from the secret service
informed them that more transports were sailing.

"Come with me and get on your pine tree outfit, Willie," suggested
their leader.  "You other boys go to your stations at once."

Henry's task henceforth was to trail the driver of the roadster.  He
hurried away to his waiting motor-cycle.  Lew was at the wireless key
again.  Roy scurried out to the pine grove, and Willie followed his
captain to be "camouflaged."  A few moments later, dressed in his new
brown clothes, and a chocolate brown in complexion, he slipped from the
house and joined Roy.

Impatiently they waited for the first transport to appear.  It was a
long time coming.  But finally Willie picked it out with his glasses,
far up the Bay, as it nosed its way steadily through the rolling waves.
Behind it was another transport.  As the ships drew near, Willie
mounted as far up in the tree as he dared, crouching behind the tops of
the surrounding trees, and hugging his own tree trunk, motionless,
awaiting his opportunity to climb to his ultimate post.  His heart beat
fast.  His legs shook slightly with excitement.  He was trembling all
over, so eager was he to make the ascent.  On came the boats.  Long ago
they had passed Robbin's Reef.  Now they were well into the Narrows.
Suddenly the spy appeared at his window, sweeping the channel with his
glasses, his hands shutting off his vision on the sides, like blinders
on a horse.  Quickly Willie scurried up the tree, wrapping himself
closely about the slender trunk, concealing as much of his body as he
could, and snuggling behind the sparse clumps of foliage.  Then he
brought his glasses to bear, and sat silently studying the spy's house.

The interior of the dwelling was as he had guessed it to be.  There was
no partition wall in the forward part of the building, a single column
upholding the ceiling, so that, above the low sash curtains, Willie
could see entirely through the glassed-in room.  This was more than
comfortable.  Willie saw a row of low book-shelves lining the north
side of the great room.  There were numerous fine pictures and plaster
casts here and there.  A piano stood in one corner, a talking-machine
in another.  The light within seemed to flicker, and Willie guessed
that in the rear of the room, where he could not see it, a log was
burning in an open fireplace; for the days were growing very chilly.

But before Willie could complete his observations, the spy turned from
the window and walked toward a large, flat desk in the centre of the
room.  Willie shrank close against the tree and remained as motionless
as a stone image.  But the spy never once glanced out of the window.
He sank into a chair before the desk, switched on an electric desk
light, and began to write on a piece of paper.  Evidently he was
arranging his message.  When this was done to his satisfaction, he
reached into the desk and drew forth a dollar.  Willie could see it
plainly as the spy laid it on his desk blotter, under the lamp.
Intently Willie strained forward.  The spy leaned forward and fumbled
about the bottom of his desk.  His hands and arms were hidden and
Willie could only conjecture what was happening.  Then Willie gave a
little gasp of surprise as the spy straightened up and laid on the
blotter beside the dollar a curious little thing like nothing Willie
had ever seen.  Evidently it was of metal for it shone under the light.
Willie screwed up his face as he strained his eyes to identify the
object.  It seemed to be a disc of exactly the same size as the dollar.
Yet it was not solid, because Willie could see the blotter through it.
To Willie the thing resembled nothing so much as a spider-web.  What it
was, Willie could not even guess.

Meantime the spy had pulled open a drawer, from which he took a slender
instrument, which also Willie could not identify.  But evidently it had
a sharp point; for the spy, after placing the disc on the dollar,
scratched the milled edge of the coin with the little instrument, then
he began to make marks here and there through the little disc, on the
surface of the dollar.  From time to time he turned the coin, and
occasionally he looked at the writing on his paper.  He seemed quite
expert, for he worked fast.  He finished his task and leaned over
behind his desk, evidently to put the curious disc in its secret
repository.

Quick as a flash, Willie slid from his exposed perch and safely gained
the concealing shelter of the lower tree tops before the spy
straightened up again.  Willie climbed on down the tree and joined Roy
at the usual observation post.

"What did you see?" asked Roy eagerly.

When Willie had told him, Roy groaned.  "Gee!  That makes it all the
harder.  Now we've got to get one of those discs as well as a marked
dollar before we can discover how they send their messages."

The grocer's boy came and went.  Roy trailed him back to the store, but
prudently kept out of sight.  There was nothing to be gained by
entering the store again.  Meantime Willie scrambled up to the house
and related to Lew and his captain what he had seen.  And they agreed
with Roy that the problem, instead of being easier, had become more
difficult.




CHAPTER XIII

WHAT HENRY DISCOVERED

Henry, meantime, was waiting at his station with eagerness and
quickened determination.  Despite his leader's generous words, Henry
felt in his heart that his last effort had been a failure.  It was true
that he had made it possible to learn the identity of the driver of the
roadster, and that the secret service men had in the meanwhile been
looking up the man's record; but Henry felt that he should also have
discovered the location of the secret wireless.  Now he made up his
mind that nothing should balk him in the present attempt.  That neither
accident nor anything else should hinder him from accomplishing his
purpose.  He would be more skilful than he had ever been before.  He
would watch closer.  He would follow his quarry, as silently as a
shadow and as closely.  He would do all that his leader expected of
him--and more.

Thus resolving, steeling his mind to the greatest effort of his life,
Henry stood at the little window in the garage, all atremble with
eagerness.  He thought he knew every inch of the spy's roadster, but
when that car finally rolled past, Henry studied it as he had never
studied anything before.  Again he noted the tread of each tire and
looked for cuts or other distinguishing marks in them.  As good luck
would have it, a turning wagon obstructed the roadster just as it
reached the little garage, and the roadster came almost to a dead stop.
Henry studied its running-gear, its radiator and bonnet, its dash-board
and wind-shield.  And when his eyes got so far, they went no further.
The standards that held up the wind-shield were bulkier and thicker
than any other such parts Henry could remember.  The difference was not
great, yet there was a difference; and like the accomplished scout he
was, Henry noted that difference and questioned it.  But, like Willie
with the spider-web disc, he was completely puzzled.  The enlarged
standards might mean anything or nothing.  The car rolled on and again
Henry looked in vain at the number.  Some part of it was always dust
covered.  But Henry observed that the hidden figures were not the same
from day to day.

When the car returned from the grocer's, Henry jumped to his
motor-cycle and made his way to the ferry by a route different from the
roadster's.  He knew he was taking a chance, but he also knew that an
accomplice might be trailing the roadster to see if the latter were
watched.  Henry could follow the spy to the ferry once without arousing
much suspicion; but if he were twice seen to do so, his usefulness
might be ended.  He knew when the ferry-boat would leave its slip and
he made his way aboard just before the gate closed.

At once he had a feeling that he had acted wisely.  The roadster was
again in the forward part of the boat, but this time the driver did not
sit placidly looking out over the Bay.  He seemed nervous, and every
little while turned sharp around and looked about him.  Fortunately
Henry had concealed his wheel behind a truck and was himself where the
spy could not see him.  When he noted the spy's restlessness, it
flashed into his mind that perhaps the secret service men who had been
investigating this spy had not been so careful as they should have
been, and that the spy had taken alarm.  It was a discouraging thought,
for it made Henry's task vastly more difficult.  Wisely, therefore, he
went into the cabin and sat down.  The spy could not see him, and if
the latter should stroll about the boat, there was nothing to indicate
to whom the motor-cycle belonged.

As the gate opened and the roadster rolled from the ferry-boat, Henry
prudently remained well behind it.  Up Broadway they went, as fast as
the traffic would allow, their pace gradually quickening as they drew
away from the congested lower end of the island.  The spy drove
straight up Broadway.  He circled Union Square and continued north.  He
passed Madison Square and still held to Broadway.  Past the shopping
district, past Longacre Square, past Columbus Circle, the roadster
continued, still on the city's main highway.  And at a discreet
distance Henry followed.

Now they reached the apartment-house district and slid past block after
block of bulky living apartments.  And so they continued past Columbia
University and down the grade beyond.  And here Henry's troubles began.
The roadster turned to the left, and Henry knew the driver was making
for the Fort Lee ferry.

How should he gain the boat unnoticed?  How should he follow,
undetected, along the Jersey roads?  For after they had crossed the
Hudson there would be an end to that concealing traffic that had so far
hidden him.  He must follow the roadster over lonely roads and yet
remain unseen.  It was a problem to disturb any one.  And it worried
Henry not a little.  Fortunately dusk was at hand, though the
curtaining darkness would not fall for some time.

When the boat reached the Jersey shore, Henry permitted the roadster to
get a long start before he went ashore.  The spy turned to the right
and began to climb the long grade parallel to the river, that would
lead him to the top of the Palisades.  When the roadster was almost out
of sight, Henry mounted his motor-cycle and followed.  Even if his
quarry should pass completely from view, Henry had no fear of losing
him; for the roadster's tracks were plain in the dusty road.

The dusk deepened.  As it grew darker, Henry came closer to his quarry,
though he kept behind elevations and curves in the road so as still to
remain invisible to the driver of the car ahead.  Thus they rode for
some miles.  The country was as Henry had pictured it from his study of
the maps.  It was sparsely built up, woodlands were on every hand, and
the surface of the land was rolling and rock-strewn.  It was an
excellent place in which to hide--and also an excellent place in which
to dodge one's enemies.  As Henry thought of this, he drew closer and
closer to the car, though still seeking to remain out of sight.  As the
light failed, and it became difficult to distinguish the marks in the
dust before him, Henry drew up so that he could see the roadster, but
he discreetly rode close to the side of the highway, where the
overhanging trees shadowed him.  Even had the roadster's driver been
looking straight in his direction, he might never have seen Henry.  He
was, as he had determined to be, a veritable shadow.

So they rolled northward.  At last it grew dark.  The driver of the
roadster switched on his lights.  Now Henry crept still closer.  He was
in the dark, his lamp unlighted, his motor running silently, and he had
no further fear of discovery.

It was well that darkness had come.  They had now reached a lonely
region where there were few houses.  Here, Henry judged, was an
excellent place for a secret wireless.  And he judged correctly, for
hardly had the thought come into his mind before the roadster turned
sharply to the left and disappeared.  Henry darted up the road.  He
came at once to what he judged was a large field.  Trees no longer
bordered the highway on the left side.  Dimly Henry saw objects here
and there which he thought were boulders and clumps of bushes.  He saw
no light and stood for a second peering into the darkness, listening
with bated breath.  Straight ahead of him he heard the faint purring of
a muffled motor.  He knew that he was not many hundred feet behind it
and that this time the car could not escape him.  He thrust his
motor-cycle into some near-by bushes, first whipping out his metal
cane.  Then he ran speedily but carefully after the car.

Evidently it was moving cautiously.  Henry rapidly drew near to it.
When he had come so close that he could see it distinctly, he dropped
to a walk and began to look about, trying to see what was around him.
Here in the field it was lighter than it had been on the highway under
the shadowing trees.  The field was, as Henry had guessed, a piece of
wild land, grown up with thickets, with great boulders here and there.
Directly ahead of him was a clump of bushes.  Henry hastened to put
them between himself and the car.  It was well he did; for hardly had
he gotten behind them before the car stopped and the driver got out.
The car was not more than two hundred feet distant.

Henry dropped to the ground and lay still for a moment.  Then he crept,
like an Indian, toward the sheltering thicket.  Through it he advanced
until he was not more than fifty feet from the motor-car.  He could see
with fair distinctness, but was himself completely concealed.  He lay
like a log, watching intently.

The driver unfastened his top and slid it backward.  As he did so, his
overcoat caught on the open door and he gave an exclamation of
impatience.  When he had laid his top back, he lowered the upper half
of his wind-shield.  Then, standing on the running-board, he tugged at
the top of his wind-shield standard.  Up came a sliding inner tube.  In
a flash the entire mystery stood revealed to Henry.  The wind-shield
standard contained a collapsible mast, like the telescoping cane he
held in his hand.  Doubtless an aerial was now fastened to the mast.
Somewhere within the car was a wireless outfit.  Instead of having many
secret stations, the Germans had this one portable station.

[Illustration: Up came a sliding inner tube]

"How clever!" thought Henry.  "And how well they deceived us."

The spy proceeded to run up his mast.  It must have reached twenty feet
into the air.  And the aerial was dangling from it, too.  Evidently the
spy had fastened that on before raising the mast.  Fifty feet distant
stood a tree.  The spy took something from the baggage container and
walked over to the tree, where, Henry judged by the sound, he was
fastening a hook.  Then the spy carried over the other end of his
aerial and fastened it to the hook.  In the darkness Henry could see
nothing of the details of this outfit, but he realized that the spy now
had an aerial at least fifty feet long and well above the ground.  For
short distance communication it would answer perfectly.

The spy returned to his car and got into the seat beside the driver's.
Henry wormed his way forward as far as he dared, hardly breathing,
fascinated by what he beheld.  For now he could see plainly.  The spy
had turned on a tiny light on his dashboard.  Cautiously Henry rose to
his feet, keeping behind a thick bush, and peered over the side of the
car.  The spy took a key from his pocket and unfastened a hidden lock.
The entire cowl board turned down, revealing a compact but powerful
wireless outfit.  The aerial wire evidently was strung up within the
collapsing mast.

From within the cowl the spy drew forth a curious metal disc, not
unlike a spider-web, and like nothing Henry had ever seen.  He did not
know what it was.  He hardly breathed as he stood watching.  Then the
spy took a dollar from his pocket, examined the milled edge until he
found a scratch, fitted the curious disc over the dollar, and turning
the coin in his hand, slowly began to make letters on a slip of paper
on the inverted dash.  When he had finished writing, he fastened the
disc back in the cowl, dropped the dollar in his overcoat pocket, and
began to send the message he had deciphered from the dollar.

Henry leaned forward.  He had no need of his own receiving instrument
to catch the letters.  And he could not have used it if he had needed
it.  But it was not important that he should catch the message.  The
powerful sparks that were leaping across the spy's spark-gap told him
that a battery of considerable force was being used, and he knew that
Lew would catch that message away back on Staten Island.  Lew had
caught the preceding message from Long Island, and it had been sent
from a distance fully as great as this.  With distinctness the letters
came to Henry's ears and he realized that the man before him was an
expert operator.  But the letters he heard made no sense.  They would
have to be deciphered before the message could be understood.

However, it was not the message that Henry was thinking of.  It was the
dollar in the man's overcoat.  "How could he get it?  How could he get
it?" he asked himself over and over.  A hundred wild ideas flashed
through his head, but he could think of no way to secure the coin
without betraying himself.

Even as he was considering the matter, the spy finished sending his
message and snapped off his light.  Tiny as the illumination had been,
the man was apparently completely blinded by the sudden darkness.  As
he stepped from his seat, his overcoat again caught on the swinging
door.  With an impatient oath he tore the coat from him and flung it on
the running-board.  Then he felt for his tools and walked over to the
tree to lower the far end of his aerial.

Henry's chance had come.  With a bound he was beside the car.
Crouching, he seized the huddled coat, ran his hands tremblingly over
it, located the pocket, found the dollar, dropped the coat where he had
gotten it, and slipped back to his cover.

He was not a second too soon.  In his eagerness to get the coin he had
been clumsy, and had fumbled excitedly for several seconds before he
found it.  Meantime, the spy, with practised skill, had taken down both
wires and fastening, and was well on his way back to the car.  But
Henry gained his cover and was safe.

A sudden fear smote him lest he betray himself.  His heart beat so
loudly he was sure the spy would hear it.  His breath came so excitedly
he was certain he could be heard yards away.  For some time he crouched
motionless, hugging the ground, trying to hold his breath.  But as
second followed second and the spy made no outcry, Henry gained
confidence.  Suddenly a feeling of exultation came to him, so strong
that he could hardly refrain from shouting.  For the first time he
thought of the real significance of what he had accomplished.  He had
unraveled the mystery of the wireless.  He had the dollar.  The secrets
the wireless patrol had worked so hard to uncover were within his
grasp.  As the full meaning of it all came to him, he felt that he must
cry out, that he must give voice to his feelings.  He no longer dared
trust himself to remain where he was, lest he betray himself.
Clutching the dollar as he had never clung to anything in his life, he
picked up his cane and slowly began to worm his way backward, on his
belly, from the thicket.  With the utmost caution, an inch at a time,
he moved, lest he snap a stick or strike a stone with his foot.  As
soon as he was clear of the brush, he faced about, and crawled into the
darkness.

The spy, meantime, was proceeding rapidly in reassembling his car.
Henry heard the windshield go up and the top being fastened.  He heard
the baggage lid snap into place.  Then he heard the spy swearing in a
low voice.  Henry stopped, still as a hunted rabbit.

"_Donnerwetter!_" he heard the man say.  "I've lost that dollar."
There was a pause.  Then came the words, "I'm not going to hunt for it
anyway.  Somebody would see my light sure.  And if anybody does find
it, he'll never guess what it is."

Exultantly Henry rose to his feet, and crouching low, ran with soft,
swift tread to his motorcycle.  He had the dollar.  The owner believed
it was lost.  Never was such luck.  Trembling all over, he fastened his
cane to the frame of his wheel, trundled his car to the road and ran
with it in the direction he had come.  He pushed it until his breath
was coming in gasps.  Then he turned into the woods and hid.  He would
take no chance of being seen by the spy or by any accomplice who might
have followed him.  Presently Henry heard the motor-car pull out into
the road and go speeding back toward Manhattan.  A quarter of an hour
later Henry returned to the highway, switched on his light, and was
soon bowling along on his way to his fellows and his chief, feeling
that he had in his keeping the future safety of a nation.




CHAPTER XIV

THE RIDDLE SOLVED

In the house above the hawk's nest, four boys and a man sat far into
the night, examining a marked dollar and trying to unravel the secret
of the scratches.  From hand to hand the dollar passed and was examined
now this way, now that; but the little group could see no meaning in
the apparently aimless marks on the silver coin.  Had some of them not
seen this dollar marked and its message deciphered and sent vibrating
through the air, they would have refused to believe that the coin
before them carried a message at all.  It looked like any dollar that
has accidentally become marked.

"To-morrow," said Captain Hardy, "we will turn the dollar over to the
secret service, and doubtless their experts will solve the problem
quick enough.  But I certainly wish we could unravel this thing
ourselves.  Wouldn't it be an achievement for the wireless patrol!"

"It's going to be," declared Roy positively.  "We're going to solve it.
We've just got to.  We'll show those secret service men that boys are
some good after all."

But the word was easier than the deed.  Puzzle their brains as they
might, search the dollar as they would, they still found no key to the
language it spoke.

"Tell me again what the message was," demanded Henry for the twentieth
time, and Lew once more passed to Henry the slip of paper on which he
had written the message, both in cipher and deciphered, the message he
had picked from the air.  It read as follows: TRPSLOWAOSEDONBADATSTITY.

  T R P S L O
  W A O S E D
  O N R A D A
  T S T I T Y

Long Henry studied the piece of paper, softly reading the message to
himself.  "Two transports sailed to-day.  How did that automobile
driver get that message from this dollar?" he asked himself, and again
he picked up the coin and turned it in his hand.  "If only we had that
disc," he sighed, "or a duplicate."

At the word "duplicate," Roy pricked up his ears.  "Maybe we can make
one," he said.

"Likely!" scoffed Lew.

"You never know till you try," rejoined Roy.  Then he turned to Willie
and demanded, "What was the disc like that you saw?"

"If I knew, I'd make one," said Willie.

"Well," said Roy in a tone of disgust, "you know whether it was a foot
across or not, and whether it was round or square."

"It was round, of course," said Willie, "and the same size as the
dollar.  I told you that before."

"We can make a disc the size of a dollar, anyway, even if it doesn't
get us anywhere," said Roy, putting the coin on a sheet of paper and
outlining it with a pencil.  Then with scissors he cut the disc out.

"You saw that disc, or one like it, Henry," continued Roy.  "What did
it look like to you?"

"Just like a spider-web, as Willie says," replied Henry.

"All right, we'll make a spider-web," said Roy.

He seized his pencil, made a dot in the centre of the disc, and from
the dot drew straight lines that radiated in different directions.
Then he drew a number of concentric circles about his dot.

"I don't see how that helps any," he said, examining his drawing.  "Yet
that's the kind of thing they used to mark that dollar."

From hand to hand the paper passed, and each boy compared it with the
dollar.  But none was any the wiser when he had finished.  Their
leader, meantime, sat with his head in his hands, studiously turning
the matter over and over in his mind.  For a long time he could make
nothing of it.

After a while he looked up.  "Let me see that paper," he said.

Roy handed him the little disc.  Captain Hardy laid the disc beside the
dollar on the table, and painstakingly examined again the marks on the
coin.  After a time he took a sheet of paper and across it in a row
wrote down the letters of the alphabet.  Then he picked up the message
and made check marks below the letters in his alphabet as he found
those letters in the message.  When he had gone through the message,
his paper looked like this:

  ABCDEFGHIJKLMNOPQRSTUVWXYZ
  /  //   /  / /// ///  / /
  /  /          /  ///
  /             /   //
                     /


He picked it up and studied it.  "Four T's," he said, "three S's, three
A's, and three O's.  That ought to give us a clue."

Again he turned to the dollar and began to study it, turning it slowly
round, counting the scratches this way and that, making geometric
figures of them.  Four heads peered over his shoulder as he worked
silently with his pencil.

"I can make nothing of it," he said after a time.

Again he sat in deep thought, his fellows meanwhile once more examining
dollar and disc and the figures their leader had made on the paper.

"Four T's," repeated Captain Hardy after an interval.  "Surely that
ought to give us a clue."

Once more he studied the penciled disc.  Then he turned to the dollar
and again examined its markings.  He suddenly exclaimed, "Here are four
scratches in a straight row."  His eyes began to shine.  Slowly he
turned the coin.  "And here are three in another row, like this," and
he indicated the positions of the scratches on the paper disc.  "You
notice that each row runs from the centre of the coin toward the edge.
Let's see if there are any more rows."

Very slowly he turned the dollar.  "And there are three in a row," he
said, indicating the scratches with his pencil, "and here are three
more.  You notice that the rows all radiate from the centre, like
spokes in a wheel.  I believe we are getting somewhere, boys."

"'Like spokes in a wheel,'" repeated Roy to himself.  "Rows of letters
like spokes in a wheel.  Four scratches in one row or spoke--these must
be the four T's.  Three scratches in these other rows must be O's and
A's and S's.  I've got it!  I've got it!" he suddenly shouted.  "There
must be as many spokes as there are letters in the alphabet."

"I believe you are right, Roy," said Captain Hardy, looking up with a
gleam in his eyes.  "That's exactly what I am beginning to think.
We'll soon see if you are right.  Make me another disc."

With a pocket rule he measured the diameter of the dollar.
"Practically an inch and a half," he announced, putting down the
figures 1.5 on paper.  He multiplied those figures by 3.1416.

"That," said he, pointing to the resulting figures, 4.71+, "represents
the circumference of a dollar.  Now we'll divide the circumference by
26, the number of letters in the alphabet."

He performed the division.  "Eighteen one-hundredths of an inch," he
announced.  "That's practically a scant fifth of an inch.  We'll call
it so, anyhow," he continued as he marked off the space on a sheet of
paper with his rule.  "Each sector," he said, "gets exactly that amount
of space on the circumference."

He pulled open the drawer of the desk and began to rummage through a
tray full of pens, pencils, and other drawing materials.  "I wonder if
there is such a thing as a pair of dividers here," he remarked.  And a
moment later he exclaimed "Good!" and drew forth the compasses he was
looking for.

He set his dividers according to the space he had marked off with his
rule, then proceeded to divide the circumference of the new paper disc.
When he had gone completely round the disc, he seized pencil and ruler
and began to draw lines from centre to circumference--the spokes of his
wheel--each spoke running from the dot in the centre to one of the
points indicated by the dividers.  When he had finished, the disc was
divided into twenty-six equal sectors, like tiny pieces of a pie.

"We shall soon know whether you are right or not in your guess, Roy,"
said Captain Hardy.

He laid the dollar beside the disc and began to copy on the disc the
marks on the dollar.  "We'll put four marks in this sector," he said,
making four dots with his pencil.  "They are like those four scratches
here," and he pointed to the four marks in a row on the dollar.  "They
must be four T's.  At any rate we'll call this the T sector.  On the
dollar you notice this row of three scratches--the next sector to the
left of the T sector.  You remember we had three O's, three A's, and
three S's.  These three scratches must, therefore, be O's, A's, or S's.
Since they are next to the T's, they are doubtless S's.  I'll mark the
sector so anyway.  That gives us the T sector and the S sector.  If we
are on the right track, then the sector to the left of the S space is
the R sector, and so on.  I'll mark the disc that way, anyhow."

Slowly he turned the disc around, putting a letter at the bottom of
each sector.  When he had finished, he had completed the alphabet.
About him clustered his four comrades, too deeply interested to speak.
They hardly even breathed.

"Take this paper, Roy," said Captain Hardy, "and tell me how many times
each letter in the message appears."

Roy took the paper on which Captain Hardy had made his numerical
enumeration.  "Three A's," he said.

Captain Hardy made three marks in the A sector.

"No B's, no C's, and two D's."

The D's were scored.  So they went through the alphabet.  When they
were done, the markings on the disc were practically a duplicate of
those on the dollar, for Captain Hardy studied the dollar each time
before marking the paper disc.

"That's it," cried Willie.  "That's it exactly."

"It's right so far as it goes, Willie," said their leader, "but we
haven't all of it yet.  Suppose I hand you a disc with four T's, three
S's, two Z's, three L's, and so on.  Could you make a message out of
it?"

Willie studied the disc on the desk.  "No," he said, "I couldn't.  I
shouldn't know how to arrange the letters to make words out of them."

"Neither would anybody else," continued Captain Hardy.  "Those spies
have some way of knowing how to tell the order in which to read these
letters."

For some time he sat studying the scratches on the dollar.  The four
boys were quiet as mice, each trying to solve the problem that stood
between them and complete mastery of the cipher.

"You said that the metal disc resembled a spider's web," began Captain
Hardy, talking more to himself than to the boys.  "We know what the
straight lines--the spokes--are for.  The concentric circles must be to
indicate the order of the letters.  Let me see."  Again he studied the
dollar closely.  "Some of these marks are near the centre of the disc,
some half-way between centre and circumference, and some close to the
outer edge.  I believe the secret lies there."

"Listen!" cried Willie of a sudden.  "When a spider spins a web, she
begins at the centre and works outward.  Maybe these spies write their
messages in the same way."

"Willie," cried Captain Hardy, "you've hit it exactly.  You're as good
a reasoner as you are an observer.  Now we'll begin at the centre and
spin this message outward.  What's the first letter?"

"T," said four voices together.

The captain took his dividers and found the scratch nearest the centre
of the disc.  In the same sector with this scratch were three other
scratches in a line.

"It's a T," he announced, "just as it should be."

With his dividers he found the letter next nearest to the centre.  It
stood alone.  "That's a W," he announced.

Rapidly he located the scratch the third nearest to the centre.  "And
that's an O," he said, looking up with flashing eyes.  "We need go no
farther.  We have the entire secret.  We have deciphered their cipher."

A cry of exultation arose.

"To-morrow," continued Captain Hardy, "we will get a piece of
transparent celluloid and make a disc like their own.  We can ink in
the circles and the radius lines and our disc will be almost a
duplicate of theirs, except that our disc will be solid while their
discs have open spaces between the circles.  But that is only a detail.
We can read their cipher as well as if we had one of their own discs."

"Wait," cried Willie, as his comrades started to cheer again.  "What is
the scratch on the milled edge of the dollar for?"

"That," replied Captain Hardy, "is to indicate how the disc is to be
placed on the dollar.  That scratch is exactly between the Z and the A
sectors.  It shows where the alphabet begins.  Now we have their entire
secret."




CHAPTER XV

ANOTHER MYSTERY UNRAVELED

A piece of transparent celluloid, furnished by their host from a broken
side curtain of his automobile, supplied Captain Hardy with the
material needed for making the disc that was to be the key to future
communications of the enemy.  Carefully he cut the celluloid the size
of a dollar, then marked the exact centre of it.  Next he clamped the
disc on the captured coin.  Between the rows of letters he scratched in
the straight radius lines--the spokes of a wheel.  Then Captain Hardy
put the end of one arm of his dividers in the dot at the centre of his
disc, and swept the other arm around, scratching a circle just outside
the first letter in the message--the innermost T.  Examination showed
that this circle fell just inside of the second letter in the
message--the W.  Adjusting his calipers, the draughtsman made a second
circle, just outside of this second letter.  A third circle fell
between the first O and the second T of the message.  So Captain Hardy
continued, each succeeding circle falling just outside of the
succeeding letter in the message.  When he had finished, his disc
contained twenty-three concentric circles, between which could plainly
be seen the bright dots or scratches in the dingy dollar.

"Whew!" said Captain Hardy, as he laid down his dividers.  "That's
pretty fine work--twenty-three circles within a space of an inch and a
half.  I'll wager a watchmaker made their pattern for them.  The solid
parts of their metal discs can't be much larger than these lines I have
scratched on the celluloid.  You were right when you named it, Willie.
The parts of it must be just about as thick as a spider-web."

The boys passed the dollar and its superimposed disc from hand to hand,
examining them with eager interest.

"Suppose they wanted to send a message with more than twenty-four
letters in it," said Roy.  "How could they do it?  I'm sure some of the
messages we intercepted had more than twenty-four letters in them."

Captain Hardy picked up the disc-covered dollar and studied it
intently.  "I suppose," he said after a time, "that they would put more
than one dot in the same circle, and the dots would be read in the same
way they are now.  The one to be read first would be nearest the centre
of the coin, and so on.  Or they could write on several coins, each
coin being numbered in some way, and corresponding to a paragraph in a
composition."

Again he studied the dollar closely.  "Clever!" he said admiringly.
"Mighty clever!  Who would ever dream that those tiny scratches meant
anything?  Many a time I've seen a dollar scratched and nicked a deal
worse than this one is, though they've evidently chosen a battered one
so that their own marks will be less noticeable.  Why, that coin might
have passed through our hands a hundred times, and if we had not
actually seen it marked we should never dream it said anything other
than 'In God We Trust.'  We've had a great stroke of luck, boys."

He paused and meditated.  "I wonder if it is luck," he went on.  "May
not the motto on that dollar explain our good fortune?  Perhaps it is
Providence rather than blind luck that has guided us.  At any rate let
us hope so.  Now I'm going to report to the Chief.  Won't he get a
surprise?"

And Captain Hardy left his subordinates, chuckling at the prospect of
the Chief's astonishment.

But it was Captain Hardy who had the surprise.  Instead of the stern,
silent, brusque man he had become accustomed to, Captain Hardy found
the Chief smiling and talkative.  As his eye fell on Captain Hardy, the
Chief rubbed his hands with apparent satisfaction.  Evidently something
had happened that had put him in an extremely good humor.

"Ah!  Captain Hardy," he said, "we beat you to it this time.  I already
know what you have come to tell me.  But I am glad to see you just the
same.  One of our operators," continued the Chief, "happened to be
shifting his tuning-coil when our friends, the enemy, were sending
their message yesterday afternoon, so that I have all the latest spy
news."

He paused and smiled at his astonished visitor.  "You see," he added, a
real Irish twinkle coming into his eyes, "the secret service is not so
slow after all."

"Congratulations!" cried Captain Hardy, in the same spirit of fun.
"The secret service is improving.  But I have some news that may make
my trip not altogether without interest to you."

The Chief interrupted him.  "We know who the man is that has been
telephoning to your Staten Island grocer about sugar," he said.  "When
he called up yesterday afternoon, the telegraph operator flashed the
tip to my man, who happened to be on duty within a few doors of the
place the man was talking from.  Of course my man spotted him and
trailed him.  The fellow proves to be a clerk on one of the piers where
transports are loading.  His position gives him no opportunity to get
aboard the ships, so he does not know what goes into the transports.
But he does know how many boats are loading and about when they will
sail.  Evidently he is afraid to telephone directly to any of the
better known German agents we are watching, and as far as that goes he
may not even know who they are.  I suppose this plan of communicating
with Staten Island is to give the spy there a chance to observe the
transports as they sail from the harbor, and see if he can learn
anything about their cargoes.  We have put this steamship clerk under
observation and from now on he will be watched night and day.  We're
closing in on them fast."

"Congratulations!" cried Captain Hardy again, this time in sober
earnest.  "You are doing excellent work.  Now when you hear what we----"

Again the Chief interrupted him.  "Oh!  I haven't told you all _my_
news yet, not by a long shot," he said.  And again the head of the
secret service rubbed his hands together.  "We know who the driver of
the wireless motor-car is.  I don't mean we know the name he's using.
Anybody could get that out of a directory.  It's Sanders.  But we know
who he really is.  And that's why we feel so good to-day.  He's a man
we've been looking for for months.  He is one of the German agents
implicated in the papers we seized in Wolf von Igel's office.  The
secret service has been more than anxious to discover his whereabouts.
Now we have him, for he's under observation and cannot escape us.

"He came to this country about a year before the war started,"
continued the Chief, a gleam of satisfaction shining in his eyes, "and
bought out an insurance agent who made a specialty of insuring suburban
properties.  From the beginning, he made a practice of visiting the
properties that he insured.  This took him about a good deal and gave
him an excuse for being so much in a motor-car.  Ah!  What an ideal
situation for a spy!  Clever, aren't they?"

But the Chief gave his visitor no chance to reply to his query.
Smiling again, he went on, "But even this is not all.  Of course you
understand, Captain, that your boys are not the only amateurs helping
us out in this pinch.  Ever since we became convinced that the Germans
have a line of secret wireless stations by which they are relaying news
to their agents in Mexico--for we're morally certain that is where
these messages go--we've had trusted amateurs helping us just as you
have helped us--by listening in.  Some of them have been at it for
weeks.  When we could get no trace of secret messages along the direct
route to Mexico, where they would naturally have their stations, we
began to suspect that the Germans were using a round-about route in the
hope of deceiving us completely."

"And you've located some of them?"

"Exactly.  Your boys will tell you that yesterday was one of those days
when radio communication is at its best--when an operator picks up
sounds that at other times he could not possibly hear.  The result was
that we picked up yesterday's secret message at half a dozen different
points.  Where do you think the first one was?"

"Give it up."

"Buffalo--north instead of south.  Clever, eh?  Then we got it near
Detroit, and Milwaukee, and Omaha, and Santa Fé.  Finally one of our
listeners picked it up at Socorro, a place about one hundred and
seventy miles north of El Paso.  Now we know the line of their
stations.  We'll set a regiment of amateurs to listening in along that
line and we'll locate every station in it in no time.  Then we'll grab
all their agents at the same time in one big raid and wipe out this spy
system for good."

"That is great news," said Captain Hardy, his eyes sparkling with
interest.  "Great!  You certainly have cause to feel good."

"For a little while," replied the Chief, "I thought I had even more
good news.  But it proved to be a false alarm."

"What was it?" inquired Captain Hardy as the Chief stopped speaking.

"Oh!  Simply this.  Some time ago one of our listeners caught an
earlier message near Socorro, which gave us a hint as to where the
messages were crossing the border.  We at once sent a number of expert
army wireless men into that part of the border region to listen in.
One message was picked up at a point fifty miles north of the boundary,
but it was very faint.  Along the line itself the radio men have never
detected a sound.  Yet your boys are intercepting the messages here, so
we know that they are being sent regularly.  That made us think that
perhaps the messages were being telephoned the last lap of the journey
and carried over the line by a person."

"I have no doubt that your theory is correct," said Captain Hardy.

"Well, last night we thought for a time that we had the man who was
carrying the messages.  When my operator here picked up the message
yesterday afternoon, I instantly sent a message to my subordinate in
charge of the work in the El Paso district, telling him of the sending
of the message and urging extra vigilance.  Yet not one of the radio
men heard a sound.  But in the middle of the night my men grabbed a
Mexican who had slipped past the armed guards and was starting to wade
across the Rio Grande to Mexico."

"Excellent!" cried Captain Hardy.

"Good enough as far as it went," said the Chief, with a wry face, "but
it didn't go far enough.  The fellow was only a smuggler."

"Are you certain, Chief?"

"Sure as preaching, worse luck."

"Was the man searched thoroughly?"

"Now, Captain, what do you think the secret service is, anyway?  Was he
searched!  It would make your eyes pop out if you'd see the way we go
through a man.  We strip him and give him a lemon bath to bring out any
secret message that might be written on his skin, and we take his
clothes apart scientifically, I tell you.  No, this fellow had nothing
incriminating on him.  After a grueling examination, he admitted that
he had crossed the line to smuggle in some tobacco.  However, it's only
a question of time until we _do_ put our finger on the missing link.
Then for a great raid!"

"How I shall welcome that day," said Captain Hardy.  "This spy business
is never absent from my thoughts, with its menace to our boys on the
ocean."

"I think that you will soon be free to go back to the army," said the
Chief.  "Your work is about done.  This thing is coming to a head fast
now.  But of course I shall need your boys to listen in for a time, so
that we can know what the Germans are sending.  But there will probably
be no more real work for you.  We certainly are grateful for the help
you gave us, though.  We have been terribly crowded these last few
weeks."

In his pride at the work his boys had done, Captain Hardy momentarily
forgot the errand that had brought him to the Chief's office.  He stood
before the head of the secret service, smiling happily.  Again he began
to think of that long chain of secret wireless stations, so sinister
and so menacing, with voice crying treachery to voice through the air,
carrying word that at any time might cause the murder of thousands of
our brave soldiers.  Mentally he journeyed along the line of those
stations--from New York to Buffalo, to Detroit, to Milwaukee, to Omaha,
to Santa Fé, to Socorro, to Mexico.  With quick imagination he pictured
the scores of little secret stations needed to carry those treacherous
messages across so vast a span of earth.  Some he saw skilfully hidden
in forests, as the wireless had been concealed at the Elk City
reservoir.  Some he pictured in abandoned farmhouses.  Others he saw in
barns, in the stacks of ruined factories.  And some he imagined as
flinging their voices abroad amid the burning plains of the arid
border-lands.  But he could not picture to himself the invisible
messenger that took the word across the boundary.  He could not fathom
the mystery, he could not picture to himself the missing link in the
chain.  As was always the case with him, his mind began at once to
grapple with its problem--in this instance the riddle of the missing
link.  He actually forgot where he was.

"I wonder," he said, though he was really talking to himself, "what was
done with that smuggler."

"We clapped him into jail to await trial for smuggling," said the Chief.

Captain Hardy came to himself with a start, and smiled.  "You say they
got nothing incriminating on him," he remarked.  "Did your men find
anything at all?"

"Only the money he had gotten for his tobacco."

Mechanically Captain Hardy had thrust his hand into his pocket.  As the
Chief answered the question, Captain Hardy's fingers came in contact
with a silver dollar and a disc of celluloid.  Of a sudden an eager
light flashed into his eyes.  "What kind of money did that Mexican
have?" he demanded.

"Some silver," said the Chief indifferently.

"Of what denominations?"

"Dollars.  He had three of them."

"What was done with that money?" asked the captain with an earnestness
that was almost tragic.

"Oh!  The greaser made such a disturbance that the jailer let him keep
it.  He's got it with him in the jail."

A great sigh burst from Captain Hardy's lips.  "Telegraph your men
instantly," he cried, "to get those dollars.  That Mexican is no
smuggler.  He's a spy.  He's the man who carries the messages across
the border.  The messages are on the dollars.  And here's the key to
the cipher!"

And he drew from his pocket and laid before the Chief a battered silver
dollar and a curiously marked celluloid disc.




CHAPTER XVI

AN UNEXPECTED MESSAGE

"Was he surprised?" cried the four boys of the wireless patrol, as
their captain entered the living-room after his trip to the secret
service offices.

Captain Hardy chuckled.  "I think he was," he said.  "But for a time it
was I who was surprised.  The Chief knew from his own men all about
yesterday's message.  One of them picked it up.  What's more, he has a
lot of amateurs in different parts of the country listening in, just as
you are doing, and they picked up yesterday's message at enough
different points to indicate the line of the secret stations we are
after.  The messages are crossing the border somewhere near El Paso.
But the Germans are getting them across in some way other than by
wireless.  They know we'd spot their outfit quick.  The Chief thinks
some one telephones the messages the last lap and that a messenger
carries them into Mexico."

"And what about the dollar and the disc?" asked Roy.  "What did the
Chief think of them?"

"Well, he was surprised.  And what's more, we got hold of that dollar
at exactly the right moment.  The secret service men arrested a Mexican
who was wading the Rio Grande at El Paso last night.  They searched him
and found nothing on him that seemed incriminating.  They questioned
him and the fellow finally said he had smuggled some tobacco into this
country, so they put him in jail as a smuggler.  The fellow had some
money he had gotten for his tobacco--and it was three silver dollars!
The secret service men down there knew nothing of what we have found
out here, so they gave the fellow back his money.  But I am morally
certain that their man is the spy who carries the messages across the
border."

"Of course," cried Willie.  "What else could he be--sneaking across the
boundary with three silver dollars."

Everybody laughed.

"It doesn't follow that he's a spy, just because he has three silver
dollars.  He may be a smuggler, all right enough.  But I believe the
smuggling is just a blind.  If he were a genuine smuggler, he'd bring
more than three dollars' worth of stuff across."

"What have they done with his dollars now?" asked Roy eagerly.

"I don't know, Roy.  The Chief got into instant touch with his men at
El Paso as soon as I showed him the dollar Henry got.  But I left
before I knew what the outcome was.  However, I have no doubt they will
find that the dollars are what we suspect them to be."

"Gee!" said Willie.  "To think that the wireless patrol found out about
those dollars!"

"I guess the secret service knows by this time that boys are worth
something," smiled Roy.  "Before we get through, they may think so even
more."

"You're certainly not increasing in modesty," laughed their leader.

"Well, I don't care," said Roy hotly.  "It makes me tired.  Everybody
says, 'Oh!  They're only boys.'  Of course we're only boys, but look at
what we've done.  Why, the wireless patrol has got the best set of
fellows----"

But Roy's protest was smothered in a burst of laughter from his fellows.

"Well, I'm glad you feel so good over what we've been fortunate enough
to accomplish," said Captain Hardy, "for I fear there will be no more
excitement for you.  The Chief says his men now have the spy business
well in hand, and that all he wants of us from now on is merely to stay
here and catch their messages until he is ready to make his raid."

"Just what I was saying," burst out Roy indignantly.  "They won't let
us in on their raid because 'we're only boys.'  But who was it caught
the dynamiters, if it wasn't 'just boys'?  The men couldn't do it.
They tried twice and failed.  Gee!  It makes me tired."

"Never mind, Roy," said Captain Hardy smiling.  "Even if we don't have
any further taste of excitement, we can always remember that we had a
big part in catching these spies--for they're going to be caught, sure.
And you mustn't forget that if we stay here and do well the part
assigned to us, we are helping just as much as the men who actually
round up the spies.  You know Milton says 'They also serve who only
stand and wait.'  If there aren't any reserves to stand and wait behind
the lines, the men on the firing-line do not dare to push ahead.  And
besides, Roy, it is seldom that four boys play so important a part in
great deeds as you four boys already have played."

"Four boys and a man," corrected Henry.  "Without you we could never
have gotten anywhere," and Henry looked affectionately at his captain.

"Oh!  Yes, I had a part in it," agreed the captain, "but it was only a
part."

"But you read the ciphers," protested Henry.  "If you hadn't done that,
we could not have made any headway at all."

"And who caught the messages for me to decipher?  The reason we have
gotten along so well is because we work together so perfectly.  I want
to thank you boys for being so faithful.  I've given you many hard
tasks to do."

"After our experiences at Camp Brady," said Lew, "we couldn't do
anything else than be faithful.  We know by experience what happens
when we don't do our duty."

"Then you are going to listen in during the remainder of the spy hunt,"
said Captain Hardy, with an affectionate smile, "just as faithfully as
though your work weren't already done and the spice gone out of it.  I
know it will be dull and uninteresting, boys, but you've made such a
fine record that I don't want you to fall down now.  So be very
careful--if only for my sake."

"They've never talked once," said Henry ruefully, "excepting after the
transports sail.  I don't suppose they ever will except when the ships
go out.  We'll have to listen to nothing for twenty-four hours a day.
But we're going to do it just the same."

He rose and walked toward the wireless room.  "It's back to the mines
for me," he added.  And he disappeared through the doorway of the
wireless room.

But hardly had he sat down and clamped the receiver to his ears before
he cried out.  His fellows came flocking into the room.  Henry was
swiftly writing a string of letters on a sheet of paper.

"Something of moment must be afoot," said Captain Hardy, in a low
voice, "for them to be talking at this time.  It must be important,
indeed."

"It's a long message," whispered Willie, as Henry continued to fashion
letter after letter.

"Something tells me it is important," repeated Captain Hardy.  "What
can it be?  You don't suppose the secret service men have alarmed them,
do you?"

Henry finished his writing and laid down his pencil.  His chief picked
up the sheet of paper and scanned the long line of letters Henry had
made, like this:

  EEANNRDBOEUNRYWSEUTTERONSNNFEEIAYWMNVTTASANXJULEIGOKWSNVATYIZLETK


"Sixty-five," he said aloud, after counting the letters carefully.

A frown came over his face as he stood looking at the paper in his
hand.  "Sixty-five," he repeated.  "All their other cipher messages
have made four even lines.  You can't divide sixty-five evenly by four.
Boys, I believe--but we'll make sure first."

He sank into a chair, laid the paper on the desk, and arranged the
letters according to the old plan, thus:

  EEANNRDBOEUNRYW
  SEUTTERONSNNFEE
  IAYWMNVTTASANXJ
  ULEIGOKWSNVATYI


"I don't know what to do with the five letters left over," he said, as
he laid down his pencil.  Then as he ran his eye down column after
column and across each line, he continued, "But I guess it makes no
difference.  It is just as I thought.  I feel more certain than ever
that something of great importance is afoot.  They've switched to
another cipher."




CHAPTER XVII

A CHANGE IN CIPHERS

For some moments there was a complete silence in the room.  The members
of the wireless patrol looked at one another in astonishment,
questioning with their eyes the meaning of this new turn of events.
Captain Hardy sat staring at the message before him, his brow wrinkled,
his eyelids drawn close together, trying to find some new clue to the
puzzle before him.  And until he spoke, the lads of the little patrol
forbore to utter a sound.  So for some time the room remained as silent
as a tunnel.

At last the captain glanced up from his paper and noted the intent
looks bent upon him, and the deep silence.  He shook off his
abstraction.

"It looks as though we were up against it," he said.  "Every minute I
feel more certain that something serious has happened.  Why should they
be sending radio messages at this hour, when they have never sent them
before excepting after the transports sailed?  And why should they now
use a new cipher?  Their plan evidently was to use radio communication
as little as possible, lest they be detected.  So they sent nothing by
wireless but the most important news--the news of ship movements, which
had to be got to Germany at once.  All other messages they conveyed in
some slower but safer way.  We know they used the telephone, and sent
messages by a boy, and wrote on dollars, and carried messages by
motor-car, and probably sent code letters through the mails.  For all
ordinary correspondence they used these slower, safer methods.  Only
when they absolutely had to, did they employ the wireless.  So we must
assume that they had to now."

He paused and glanced from face to face.  "But why the change of
cipher?" he continued.  "It must be because they fear that the old
cipher will be understood."

Again the captain fell silent.  "What can have happened?" he inquired
soberly, "that makes the use of wireless so imperative?  What can it
be?  Only something new and unforeseen.  And what could there be new
and unforeseen except the detection of their plot?  More and more I am
convinced that these plotters have been alarmed."

He fell into a brown study for a moment.  "This message can mean
nothing else," he said after a little.  "It is imperative that we learn
what it is at the earliest possible moment.  Make four copies of the
message you took, Henry."

Captain Hardy's first lieutenant took the paper from his leader's hand
and on four sheets of paper copied the string of letters he had picked
from the air.

"Now, boys," said the leader of the patrol, when the copies were
complete, "put your thinking caps on.  Each of you take one of these
copies and see what you can make of it.  You know how we deciphered the
other cipher."

In another moment four boys were wrinkling their foreheads as they bent
over the cryptic strings of letters.  And over the room came a hush
deep as midnight's.

For a few moments nobody broke the silence.  Each boy was busy with his
own thoughts.

Henry was scowling at his paper.  Willie was studying the letters
before him, as in earlier days he had studied the landscapes about Camp
Brady and the Elk City reservoir.  Lew already had a hopeless look on
his face.  At threading the forest he was second to none in skill; but
at untangling mental puzzles, he had small ability.  The nimble-witted
Roy was already setting about his task with that keenness so
characteristic of him.

"Sixty-five letters," he said to himself.  "If this cipher is anything
like the other, those letters must be arranged in columns of equal
size."

For a second he sat scanning the letters.  Then he muttered, "What will
divide sixty-five evenly?"  And a moment later, he answered his own
query by adding, "Five, and thirteen."

He paused and again ran his eye along the row of letters.  "If this
cipher works like the other there must be five rows of thirteen letters
each, or thirteen rows of five each.  I'll try the five rows first.
That's more like the other cipher."

Swiftly he set down the five rows of letters, thus:

  E E A N N R D B O E U N R
  Y W S E U T T E R O N S N
  N F E E I A Y W M N V T T
  A S A N X J U L E I G O K
  W S N V A T Y I Z L E T K

Eagerly he ran his eye down the columns of letters, as he had become
accustomed to doing with the old cipher, but the letters were
unintelligible.  Next he read the letters across the rows, but with no
better result.  The eager look faded from his eyes.

"I'll have to try the other," he said, and began to make his letters
into rows of five each, thus:

  E E A N N
  R D B O E
  U N R Y W
  S E U T T
  E R O N S
  N N F E E
  I A Y W M
  N V T T A
  S A N X J
  U L E I G
  O K W S N
  V A T Y I
  Z L E T K


With renewed eagerness he ran his eye down the first column.
"E-R-U-S-E-N-I-N----" he began, then stopped short in disgust.
"Nothing doing that way," he muttered.

Then he read the letters across the rows: "E-E-A-N-N----"

"They've got me stopped," he said.  And he threw down his pencil and
sat staring at the paper before him, twisting the letters into every
shape he could think of, but to no avail.

Meantime each of the other members of the patrol was going through much
the same process.  Lew gave up first, acknowledging himself beaten.
Henry sat scowling and working away industriously.  Dr. Hardy tried
first one combination of letters, then another, but in vain.  Willie
had laid out the letters in exactly the same way Roy had.  But Willie
worked differently from any boy in the group.  The rest had been
feverishly setting down letters as new combinations presented
themselves to their minds, whether the combinations seemed logical or
not.  Willie first arranged his letters in the long rows and sat for
many minutes looking intently at them.

At Camp Brady it was Willie who had learned, better than any other
member of the patrol, the lesson of observation.  When the patrol was
practising scouting, which is only another name for close observing,
Willie had sat for hours studying the landscapes, even when his fellows
teased him.  Thus he had learned to see everything within sight and
make note of it.  And when a guide was needed later, to conduct a party
through the midnight woods in quest of the dynamiters' lair, Willie was
the scout who was able to do it.  He had observed perfectly and so
carefully noted what he saw that even in the darkness he could find his
way.

So now he examined his long rows of letters until he knew everything
about them; and he was certain they told no story.  When he was
certain, he rearranged the letters, as Roy had done, in rows of five
each.  Then he laid down his pencil and began another careful search.
He read the topmost line from left to right, and from right to left.
It made no sense.  He took the second and found no meaning in it.
Another boy might have skipped the others, but not Willie.  Each of the
thirteen rows he studied forward and backward.

Then he ran his eye down the first column, just as Roy had done.  It
spelled nothing.  But when he began at the bottom and came upward, an
eager light leaped into his eyes.  He could make nothing of the lowest
five letters; but the eight above certainly spelled two words: "nine
sure."  If the message was in English, Willie knew he had found
something definite to work on.  He could make nothing of the second
column, either upward or downward.  But the third column gave him
distinctly the words "twenty four."  The next column yielded more
words: "Six twenty."

By this time Willie's eyes were flashing.  He turned to the bottom of
the last column and began to read upward.  A single glance confirmed
his suspicion.

"Captain Hardy," he cried, jumping over to his chief, and laying his
paper on the captain's desk, "begin at the bottom of the last column
and read upward.  I believe this cipher is exactly the opposite of the
other."

Willie's fellows dropped their pencils and gathered eagerly about their
leader as he slowly read the letters, beginning at the bottom of the
last column and reading upward and backward in the exact opposite of
the way the former messages had been deciphered.

"K," he read, "I-N-G-J-A-M-E-S-T-W-E-N-T-Y-S-I-X-T-W-E-N-T-Y-
O-N-E-T-W-E-N-T-Y-F-O-U-R-B-A-L-A-K-L-A-V-A-N-R-E-N-D-E-Z-V-
O-U-S-N-I-N-E-S-U-R-E."

"Hurrah for Willie!" cried Roy, who had been putting down the letters
as Captain Hardy read them off.  "He's solved the problem.  Who says
boys aren't any good?  I'll bet you----"

But Roy was interrupted by his mates.  "Read it to us," they demanded.

"It's a funny message," said Roy, and slowly he read the following:
"King James twenty six twenty one twenty four----"  Then he stopped.
"I can't read the next words," he said.

Captain Hardy took the paper from Roy and read the entire message.
"King James twenty six twenty one twenty four Balaklavan rendezvous
nine sure."

"What a queer message," said Henry.  "What does it mean?"

"It means," said Captain Hardy, "that the Germans have done their very
best to deceive us.  They not only changed their cipher, but they sent
their message in code.  We have read their cipher, but we know no more
than we did before.  We can never work out their code.  All we can do
is to guess at the meaning.  Our difficulties, instead of being ended,
are just beginning.  I am more and more convinced that this message is
important."




CHAPTER XVIII

TOO LATE

The look of astonishment that appeared on every face at the reading of
the message was soon succeeded by one of bewilderment.

"How are we ever going to find out what it means?" demanded Willie.  "We
can keep juggling letters around until we get them into the proper
combinations to make words out of them.  But here we've got the words.
And they don't mean anything to us.  And I don't see how we're ever going
to find out what they do mean.  We couldn't juggle words around, too,
could we, Captain Hardy?"

"No, Willie.  There is no use trying that.  The spies know what the words
mean, all right enough.  And nobody else does, unless he has the key to
the code.  All we can do is to guess what they mean."

"It will take some tall guessing," laughed Roy.  "I don't even know what
two of those words mean.  Read 'em, Willie--those two long ones."

Everybody laughed.  "B-A-L-A-K-L-A-V-A-N R-E-N-D-E-Z-V-O-U-S," spelled
Willie.  "They've got me stopped, too.  What do they mean, Captain Hardy?"

"Balaklavan evidently is an adjective referring to Balaklava.  Does any
one of you remember that word?  You've had it in history."

"I know," said Henry.  "That's where the Light Brigade made its famous
charge in the Crimean War."

"Good," said Captain Hardy.  "That's exactly right.  So that word
evidently refers to a famous battle-ground.  Can it be that we have
stumbled on a diplomatic message instead of one meant for these spies?
Could it be that this message has anything to do with the situation in
the Balkans, I wonder?" and Captain Hardy began to turn the matter over
in his mind.

"You didn't tell us what that other word meant," said Roy.

"Oh!" said the captain, with a smile.  "That's a word of French origin
that means meeting-place.  Balaklavan meeting-place, Balaklavan
meeting-place," repeated the captain.  "This certainly must be an
important message.  The Chief ought to know about it at once.  But I
wouldn't dare telephone it.  I'd have to take it to him."

"Maybe _we_ could find out what it means," said Roy, "if only you would
stay to direct us.  Wouldn't it be great if the wireless patrol----"

"Roy," interrupted the patrol leader, "I know how you feel.  You are very
loyal to the wireless patrol.  But this is a case that calls for loyalty
to Uncle Sam first.  The important thing is to get the message read--not
to have it read by any particular persons."

"Let me take the message to the Chief," suggested Lew.  "I am no good at
this sort of thing, but I can carry a message as fast as anybody.  Then
you could stay here and help the others."

"Very well, Lew.  Take a copy of the message as we caught it, and a copy
of the cipher as we arranged it.  The Chief will learn as much from them
as he would from half an hour's talk.  Now hurry."

In a few minutes Lew was speeding toward Manhattan with the message in
his pocket, while the remainder of the wireless patrol were drawn up
about Captain Hardy's desk, in earnest consultation.

"If only we had an up-to-date history," sighed Henry.  "Then we'd know
who the sovereigns are in the Balkans.  All I know are Peter, of Servia,
and it seems to me that he abdicated or died; and Ferdinand, of Bulgaria;
and Constantine, of Greece, who abdicated in favor of his son Alexander;
and the king of Roumania--isn't his name Ferdinand, too?"

"Then there is Charles, of Austria," suggested Captain Hardy, "and the
Turkish Sultan, and King Victor Emmanuel III, of Italy.  But I can't
think of any King James.  Well, we'll drop the kings at present and go on
with the cipher.  That brings us to three groups of letters--twenty-six,
twenty-one, twenty-four.  I know that code makers frequently use
arbitrary groups of letters or figures to represent given words or ideas,
but I haven't the slightest notion as to whether these figures belong
together or are to be read separately.  And as to what they mean, we can
only guess.  Since they seem to be in connection with some ruler and
something about a Balkan meeting-place, they might refer to troops.  You
don't suppose the Germans are massing forces for another drive into
Roumania or that part of Russia around the Black Sea, do you?"

For a little time there was complete silence, as each member of the party
struggled to remember all that he had read about the situation in the
near East.  But none could throw any light on the matter.

"Well, we will drop the numbers and go on," said Captain Hardy.  "That
brings us back to the Balaklavan rendezvous.  The word rendezvous plainly
indicates some kind of a meeting.  A number of people are going to get
together somewhere.  If the place indicated were not so evidently in the
Crimea, I should think that the message might mean that these German
agents we've been watching are summoned to a meeting somewhere."

Again there was a long pause.  "Henry," said Captain Hardy suddenly, "to
whom was this message sent, and by whom?"

"It had the same call signals that have always been used.  It must have
been sent from the motor-car station and it is intended for the same
station or stations the other messages were sent to.  But we don't know
yet where they are."

"What would this motor-car driver, Sanders, be sending out a message
about the Balkans for?" demanded Henry.  "Is he connected with the German
diplomatic corps as well as with the spy activities?"

"That's exactly what I was wondering about," replied Captain Hardy.  "I
can make nothing of it.  The only thing I can understand is the last part
of the message--'nine sure.'  Somebody is to meet somebody somewhere at
nine o'clock sure."

"If they meet at the Balaklavan rendez----  What's that word?  I can't
remember, Captain Hardy," said Roy.

"Rendezvous."

"Well, if somebody is to meet at some place at nine o'clock, the place
can't be in the Balkans--not if the people who meet are the persons who
received this message."

"You're right, Roy.  And they couldn't meet in Europe, or even very far
away in the United States, for," he continued, glancing at his watch, "it
is already long past luncheon time."

"Well," said Henry, "there wouldn't be any sense in telling these spies
about a meeting in the Balkans, anyway.  So the message must be intended
to call them to a meeting themselves."

"It must be so," assented Captain Hardy.  "And if it is so, the situation
is serious.  Why should they want to meet?  And why should the need be so
urgent that they can't wait to send their message by safer channels, but
fling it out into the air for anybody to pick up and read, if he has
brains enough to do it?  Hello!  Here's Lew back again."  And turning to
the new member of the group, the leader said, "What did the Chief think
of your message?"

"He was as puzzled as we were.  He said his cipher experts were as busy
as they could be with wireless messages of the utmost importance that the
Germans had sent from Brazil to Berlin and that government operators had
intercepted.  But just as soon as he can get a man who knows anything
about ciphers and codes, he will put him at this job."

"Then it's all the more important that we should unravel this thing
ourselves.  If something is to be done at nine o'clock, we haven't a
moment to lose."

Hastily they ate their luncheon, then filed back to their living-room,
where lay their maps, books, guides, and other equipment.

"We had better clear off these tables and desks," said Captain Hardy, "so
that we shall have plenty of desk room.  Suppose you pile these books on
that book-shelf there, Henry.  And you, Willie, put those maps on the
mantel over the fireplace."

Henry gathered up a huge armful of books and hastily dumped them on the
book-shelf indicated.  They slid down into a heap, but none fell to the
floor.  Henry, in his usual careful manner, began to set the books to
rights.

"Never mind that now," exclaimed Captain Hardy.  "That can wait until we
have more time."

Willie, meanwhile, was hastily stacking maps on the mantelpiece.  He did
not bother to fold them up, but put a weight on them and let the sheets
hang down toward the floor.  In no time the desks were cleared, and the
little group soberly seated before them.

"You've taken away the paper with the message on it," said Captain Hardy
to Henry.

Henry started for the book-shelves, but Willie, who sat nearest the
shelves, was there almost before Henry was out of his chair.  He scanned
the heap of books, looking for the missing paper.

"There it is, under that Bible," he muttered.

He lifted off the superimposed books, and shoved the Bible to one side.
The books began to slide, but Willie stopped them before they poured down
to the floor.  The Bible he caught on the very edge of the shelf, its
covers open.  He thrust the book back, seized the paper, and returned to
his seat.

For perhaps an hour the little group worked on.  Sometimes each labored
in silence, busy with his own thoughts.  Again there was eager
discussion, as one or the other advanced some theory or idea as to the
meaning of the message.  Then silence would come again.  So the hours
rolled by.  In one of these pauses, Willie sat with closed eyes, turning
the mystery over in his mind.  But his brain was tired and other thoughts
would creep in.  Once he caught himself thinking of Camp Brady.  Again he
was thinking about the East River, and all the sights he had seen on a
trip he had made up that stream into the Sound.  Rigidly he brought
himself back to his task.  But presently his attention wandered again.
Now he was thinking about the book-shelf and the volume he had caught as
it was slipping to the floor.  And then, as though a flash of lightning
had suddenly illuminated a dark place in his brain, he saw the words on
the open page of the book--words that in his haste he had barely
glimpsed, but that now came vividly to his mind:

  TO THE MOST HIGH AND MIGHTY PRINCE

  _JAMES,_
  _By the Grace of God_
  _King of Great Britain, etc._


In another instant Willie was on his feet.  "There's one King James that
we didn't think of," he said, "the King James of the Bible."

His fellows laughed.  "He's dead," said Roy.

But Willie paid no attention to the comment.  His look was centred on his
captain's face.  And his captain's face was worth watching.  Over it came
that eager look that always marked his countenance when he got new light
on a problem.

"Willie," he said, "I can't see the connection offhand, but it may well
be that there is one.  Can anybody think of any connection between King
James and Balaklava and these spies?"

Nobody could.  "The only thing that King James is remembered for,"
continued Captain Hardy, "is this very Bible--the King James' version, as
we call it, in contradistinction to the Revised version.  But I don't
quite see how we can connect him with the rest of the message.  Read the
message over again, Henry."

When Henry had read it, Roy said, "If it said Matthew, or Psalms instead
of King James, you would think that it was a text."

Captain Hardy leaped to his feet.  "Stupid!" he cried.  "Why didn't I see
it before?  Of course it's a text.  Bring me the Bible.  King James, 26,
21, 24," muttered Captain Hardy, as Roy placed it before him.  "That must
indicate the book, chapter, and verse."

He turned to the table of contents and began to count the books of the
Bible.  "Ezekiel," he announced, when he reached twenty-six.  "If our
theory is correct, this message refers to Ezekiel 21, 24.  We'll soon
know whether we're right or not."

His fingers trembled as he turned the pages, so eager was he.  He found
Ezekiel, turned to the twenty-first chapter, and ran his shaking finger
down the columns until it rested on the twenty-fourth verse.

"Listen," he said, and his companions scarcely breathed as he read:
"'Therefore thus saith the Lord God, Because ye have made your iniquity
to be remembered, in that your transgressions are discovered, so that in
all your doings your sins do appear; because, I say, that ye are come to
remembrance, ye shall be taken with the hand.'"

For an instant complete silence followed the reading.  Then Captain Hardy
said, "Willie, you've solved the riddle.  And it is just as I feared.
The Germans have been alarmed.  They know that they are detected.  Now
everything is plain enough--in a way.  They had to warn all the members
of the gang and they hadn't time to send messages.  So they took a chance
on the wireless.  But they used a new cipher and resorted to a code.  The
use of the word 'rendezvous' indicates to my mind that they intend to
flee.  They're going to meet at the 'Balaklavan rendezvous' at nine.
We've got to find where that is and get the secret service men there in
time to nab them.  And the afternoon's almost gone already."

Captain Hardy pulled out his watch and groaned as he looked at it.
"We've got to watch these spies, too," he said.  "Above all things we
mustn't let them get away from us.  If we can't find out where the
Balaklavan rendezvous is any other way, we can trail these fellows to it."

Then the leader of the scouts turned to Lew.  "Hustle down to the pine
tree," he directed, "and watch the hawk's nest.  It may already be too
late.  But if anybody is still there and comes out, trail him no matter
where he goes.  You can get into touch with me by telephone.  Meantime,
I'll communicate with the Chief."

Lew hurried away and Captain Hardy left the room to telephone.  He came
back with a white face.

"The Chief hasn't a man available," he reported.  "All his men are
watching some plotters who are trying to burn grain elevators and fire
shipping.  He says it's up to us and the police.  So I called Police
Headquarters and two detectives will be sent here at once.  Pray Heaven
they come in time."

Hardly had he finished speaking before Lew burst into the room.  "Captain
Hardy," he cried, "I was too late.  Just as I reached the pine grove, I
saw the spy running down the slope.  He was a quarter of a mile away.  I
ran after him.  But before I got near the shore he stepped into a
motor-boat that was waiting and away he went.  There were three other
persons in the boat, and I am sure one was the grocer and one his boy.  I
had no way of following them, so I came straight back."

Just then the door-bell rang.  Their hostess announced two men to see
Captain Hardy.  And the two detectives entered.

"Too late," groaned Captain Hardy.  "The birds have flown.  And we do not
know where they have gone."




CHAPTER XIX

THE ENEMY ESCAPES

Evidently the detectives were little interested in the case.  They
asked a few perfunctory questions and went away without making any
effort to intercept the fleeing motor-boat.

"They remind me of those state police at the Elk City reservoir," said
Roy indignantly, "They don't take any interest in anything they don't
do themselves.  Or maybe they think the matter isn't worth bothering
with because we're only boys."

"No, Roy," explained Captain Hardy, "I think it must be because we're
working with the secret service.  The police and the secret service are
as jealous of each other as two cats; and the police don't want to do
anything that will bring any credit to the secret service.  They might
have been able to do something to intercept that motor-boat.  But I
don't know what we can do.  What was the boat like, anyway?"

Lew was able to give a good description of it; but evidently all
distinguishing marks had been removed from it.  It was a craft of
perhaps thirty-five feet, slender, of light draft, and quite certainly
built for speed.  There was no name at either bow or stern, and the
boat was painted a muddy gray that made it almost invisible at a little
distance, so well did the color harmonize with the color of the harbor
waters.  Lew had watched it until it was almost out of sight; and all
he knew was that it had started straight out through the Narrows, as
though bound for the ocean.

"It looks at first glance," said Captain Hardy, "as though they were
going to sea; but they couldn't go far in that craft.  Perhaps there is
some larger vessel there that they hope to reach."

He turned the idea over in his mind for a time.  "I think it more
likely that they are heading for some point on land," he said.  "They
are so clever at deception that that is most likely to be the case; and
if it is, they may not even be going in the direction they are headed
for.  It will soon be dark.  Then they could double back unseen.  It's
my idea that Newark ought to be a good refuge for them.  It's a pretty
big place, and it's full of German sympathizers--and they can reach it
the way they're going.  All they need to do is to keep right on around
this island.  That will take them to Newark Bay.  I wonder if that
isn't what they're up to, anyway?"

Willie went over to the mantel and brought a large map that showed all
the waters of the region.  He spread it out on the table and the group
gathered around it, shoulders together, heads bent low.

"They might be making for Raritan Bay or Jamaica Bay," suggested Henry.

"Yes," replied Captain Hardy, "but I don't think it likely.  Quite
evidently they fear pursuit, and they will know that they are safest
where boats are most numerous.  And I should think that would be in
Newark Bay, although I don't really know."

"They could coast along the shores of New Jersey," said Henry, "or of
Long Island.  What would they be most likely to do?"

"Ah!" replied Captain Hardy.  "That's the very question.  You know what
Sherlock Holmes used to say: 'Eliminate the impossible, and whatever
remains, no matter how improbable, is the truth.'  I think that we can
eliminate the possibility of their going to sea.  That is practically
impossible--unless--unless--there's a ship out there waiting for them.
If this were England instead of America, I'd say that's exactly what
was afoot: that there was a German boat somewhere offshore waiting for
them.  But the possibility of there being such a ship here is so remote
that we can dismiss it."

"If they aren't going offshore, where are they going?" demanded Lew.

Everybody laughed.  "That's what we've got to find out," replied
Captain Hardy.

"I don't see how," said Lew hopelessly.

"No more do I," rejoined their leader, "but we'll have to start with
what clues we have and try to follow them.  All we know is that this
motor-boat is outward bound through the Narrows and presumably is going
to be at the Balaklavan rendezvous at nine o'clock."

"I wish we had a Light Brigade to send after them," sighed Henry, and
as the others laughed, he began to quote what he remembered of
Tennyson's lines that have made the name of Balaklava immortal:

  "'Into the jaws of death,
  Into the mouth of hell
    Rode the six hundred.'"


Long ago dusk had come.  The lights were lighted and the little group
of scouts still clustered about their maps, searching vainly for a
clue.  Their hostess came to call them to dinner.

"I am sorry," said Captain Hardy apologetically, "but we are at work on
a very grave matter and cannot possibly stop for dinner.  Could you
conveniently send us up some coffee and sandwiches?"

So, while they munched their sandwiches and sipped their hot coffee,
the members of the wireless patrol continued their search for the
missing clue.  Occasionally Lew, more restless than his fellows,
strolled over to the window and stood gazing out over the harbor, with
its entrancing lights.

"There goes the _Patrol_," he called out suddenly, as a boat bearing
the distinctive lights of the police department slipped down the
Narrows, while he was at the window.

Captain Hardy gave an exclamation of annoyance.  "Why didn't I think of
that boat?" he said savagely.  "We might have been able to follow the
motor-boat if we could have gotten the _Patrol_ here.  For all we know,
she may have been near at hand.  And she is equipped with wireless,
too.  Well, it's too late now."  Then bitterly he added, "The man who
ordered the charge of the Light Brigade wasn't the only one who
blundered."

"Is there any place near New York," suddenly demanded Henry, "named
Balaklava or Crimea or anything else that suggests Balaklava?"

"Get that atlas from the book-shelves and see, Henry," replied Captain
Hardy.  "Look through the list of towns, rivers, lakes, etc.  And you,
Willie, study the map a while.  That seems to be your forte.  You may
find something to suggest Balaklava to you."

Willie laid the map squarely on the table, and while Henry pored over
the atlas and the others talked, and thought at intervals, he began a
systematic survey of the map.  And naturally he began in the region of
the Lower Bay, toward which the motor-boat had disappeared.

Minute followed minute.  Dusk turned to deep darkness.  Captain Hardy
opened and shut his watch in desperation.  Swiftly the time was drawing
near for the meeting of the spies, and the wireless patrol had not only
failed at the critical moment, had not only allowed the enemy to
escape, but had lost all track of them.  It was a bitter thought and
Captain Hardy tried to shut it out of his mind and centre attention on
the problem in hand.  Henry was still poring over names.  Willie had
finished his methodical examination of the Lower Bay and was working
his way northward.  He followed the boundaries of the harbor up through
the Narrows and along the Jersey shore, then pursued his quest
throughout the length and breadth of Newark Bay.  But he found nothing
suggestive of Balaklava.  Back to the Bay he traced his route, then
slowly traversed its waters.  Past Bayonne, past Bedloe's Island, past
Jersey City, and up the Hudson his pencil slowly moved, as he surveyed
every name and looked at every turn and angle of the shore.  Then he
came back to the eastern side of the Narrows and went north along the
Brooklyn shore.  Past the Erie Basin, past Governor's Island, past the
Brooklyn Bridge, past the Navy Yard, past Blackwell's Island, past
Ward's Island, past Hell Gate, with its swirling currents, and on into
the Sound, he traveled in imagination, examining every point and word
on the map, but he saw nothing suggestive.

The minutes crept on.  Eight o'clock had already struck.  Captain Hardy
was in a fever of anxiety.  He could no longer sit still, but was
pacing the floor.  Lew, utterly hopeless of helping, stood at the
window, looking out over the myriad lights of the harbor.

"There's the _Patrol_," he said.  "She's coming back up the Narrows."

"If we only knew where to go, it wouldn't be too late yet," said
Captain Hardy in a tragic voice.  "It is awful to think that we have
failed."  In an agony of mind he began to pace the floor.

Henry had finished his perusal of the atlas and was thinking
desperately over the problem.  "I'd gladly go where the Light Brigade
went," he muttered, "if only it would take us to those spies."  And
again he began to quote:

  "'Into the jaws of death,
  Into the mouth of hell
    Rode the six hundred.'"


Hardly had he finished, when Willie gave a loud cry.  "Hell Gate!" he
almost shrieked.  "That's where they are going to meet."

Captain Hardy stopped abruptly in his walk.  The flush of hope crept
into his cheek.  "It's far-fetched," he said, "but it may be.  It's the
only chance we've got.  Can we make it in time?  Where's the _Patrol_,
Lew?"

"Right there, sir; almost out of the Narrows."

"Quick, Henry.  The wireless."

Henry rushed to the wireless room.  Captain Hardy strode after him.
The others followed.  With eager, skilful fingers, Henry adjusted his
instrument and began to flash out the call for the police-boat.

Almost at once he got an answer.  As Henry wrote down the letters,
Captain Hardy leaned over his shoulder, his eyes fastened on Henry's
pencil.

"Tell them the secret service needs them at the landing at once, Henry.
Tell them to hurry."

Then, while Henry was flashing his message into the night, Captain
Hardy ran to the window to see what the _Patrol_ would do.  On and on
it went, as though it had no intention of stopping, and cold beads of
perspiration stood out on Captain Hardy's forehead, and he clasped and
unclasped his hands in his excitement.  On went the boat.  Captain
Hardy tore back to Henry's side.

"What do they say?" he demanded.

"They're coming, sir."

Again the captain stepped to the window.  The little steamer was just
beginning to turn.

"Get your hats and coats, quick," ordered the leader.

In a second the scouts were ready.  In another, the little party
emerged from the house and started pell-mell down the hill in a mad
race to reach the landing before the police-boat got there.

Boat and boys touched the wharf at almost the same instant, and Captain
Hardy's party leaped aboard before the steamer had entirely lost her
headway.  An officer stood at the gunwale, peering through the dark at
the figures that swarmed aboard.

"I'm Lieutenant Gavigan, in command," he said, advancing toward Captain
Hardy.  "Are you the party that called us?"

"Yes," replied Captain Hardy.

A look of astonishment came over the lieutenant's face.  "Your wireless
said we was wanted by the secret service," said the puzzled lieutenant,
"but these boys do not belong to the secret service.  And I don't know
you, either."

"I will explain everything," said Captain Hardy, "but make haste.
We're after German spies that are to meet at Hell Gate at nine o'clock.
Crowd on every ounce of steam you can."

"Hell Gate!" said the lieutenant sarcastically.  "And do you think I'm
going to take you to Hell Gate, just on your say-so--you and a crowd of
kids I don't know from Adam?  What do you think would happen to
Lieutenant Gavigan if he went gallivantin' round the Bay without orders
on joy rides like that?  Nothin' doin'."

Captain Hardy smothered the indignation he felt, and began to explain
courteously.  "Lieutenant Gavigan," he said, "I am Captain Hardy of the
United States Medical Reserve Corps and these boys are members of the
Camp Brady Wireless Patrol.  Last summer we did the wireless work for
some of the Pennsylvania troops guarding public works, and in the
course of our duties were fortunate enough to detect and capture some
German spies who were endeavoring to blow up a great reservoir and
cause another flood like that which wiped out Johnstown.  For the last
few weeks we have been helping the United States secret service keep
track of German spies in New York, for, as you no doubt know, the
secret service is short handed."

"Short handed," sneered the lieutenant.  "Yes, and short minded, too,
to be employin' a parcel of kids.  But that's about as much sense as
the secret service has got.  If they want any spies caught, why don't
they call in the cops?  We'd catch 'em soon enough."

Captain Hardy choked down his resentment and went on.  "We're not
making any boasts as to our abilities, Lieutenant Gavigan," he said,
"but we are doing all we can to help and the secret service thought
well enough of us to put us to work."

The police officer looked the captain over critically.  "How do I know
you are what you say you are?" he asked.  "Where are your credentials?"

A sudden fear smote Captain Hardy.  Were all their efforts to come to
naught?  Were the treacherous spies to get away, now, when it seemed
that they might yet be apprehended?

"We have never thought credentials would be necessary," he said, "and
we have overlooked the need of providing ourselves with them.  But we
can satisfy you fully.  Only hurry, Lieutenant, hurry."

"And where should I hurry?" the latter asked truculently.  "You don't
think I'm goin' to risk my head takin' the likes of you on a joy ride
to Hell Gate, do you?  Nothin' doin'.  You come ashore and tell the
captain who you are and what you want, and if he says Hell Gate, why,
you'll get there, and if he don't, you won't.  And that's all there is
to that."

Very evidently it was useless to argue with the stubborn lieutenant.
In despair Captain Hardy turned aside, desperately thinking how to meet
the situation.  Argument, he saw, was of no avail with this type of
man.  Force would have to be used.  But what had he to offer that would
impress the man?

"Captain Hardy," said Roy, slipping up to his commander, "would our
police cards help any?"

"The very thing," said Captain Hardy.  "I had forgotten that you boys
had them."

Captain Hardy hastened back to the commander of the Patrol.
"Lieutenant Gavigan," he said sharply, "there are more ways than one a
policeman can lose his head.  One is by being a fool.  Your
Commissioner is keenly interested in this work of ours and is giving us
all the assistance he can.  Each one of my boys carries his personal
permission to go where he chooses.  Roy, show this officer your pass."

Roy produced his police card, and the three other boys followed his
example.

"Those cards were given to my boys by the Commissioner in person," said
Captain Hardy impressively.  "He is keeping in close touch with this
work.  I should not want to have to report that you blocked our efforts
and made it possible for these spies to escape."

The change in Lieutenant Gavigan was remarkable.  "Crowd on all the
steam you've got, Jim," he shouted to the engineer.  Then turning to
Captain Hardy, he said, "Why didn't you tell me you was on police
business?  I'll send a wireless message at once for instructions."

Captain Hardy raised his hand in protest.  "Impossible!" he said.  "If
the Germans should pick it up, everything would be lost.  Our success
depends wholly upon the speed and secrecy with which we travel.  How
much longer will it take to reach Hell Gate?"

"A half an hour, anyway," said the lieutenant, who was beginning to
look worried.  Then he added, "I'm takin' an awful chance, goin' up
there without orders."

"And you're taking a worse one if you refuse to go," rejoined Captain
Hardy sternly.

The lieutenant wavered.  Captain Hardy strode into the cabin and seized
a piece of paper.  Lieutenant Gavigan, curious, followed him.  Rapidly
Captain Hardy wrote a message on the paper.

"Send that to your Commissioner," he said, handing the completed
message to the commander of the _Patrol_.

Lieutenant Gavigan ran his eyes hurriedly over the paper.  "Captain
James Hardy, M. R. C.," ran the message, "and patrol of boys request
immediate assistance.  Everything at stake.  Send instructions at once."

The lieutenant looked relieved.  "The Commissioner won't be at his
office at this hour," he said, "but they'll know where to reach him."

"Then rush it," said Captain Hardy, "and make every bit of speed you
can."

He stepped out into the night again.  Overhead myriad stars twinkled
brightly.  The little craft was vibrating from stem to stern under the
rapid revolution of her engines.  She was ploughing through the water,
throwing up a great white wave on either bow.  On all sides of her
vessels were coming and going on their usual missions of peaceful
industry.  Millions of lights twinkled in the great buildings of the
city and in the factories that lined the water-front.  But Captain
Hardy had no eye for the beauties of the night or the swelling waves or
the stimulating harbor scene.  He could think of nothing but the work
ahead of him, of the rendezvous in the darkness at Hell Gate.  The
little steamer, ploughing her way through the water, seemed to Captain
Hardy to be almost motionless, so keen were his fears that he would be
too late.  He pulled out his watch and groaned.  The boat was well into
the East River, but it was already almost nine o'clock.  In agony of
mind he began to pace up and down the deck.

"Got an answer," said Lieutenant Gavigan, suddenly coming out of the
cabin, and he thrust a paper into Captain Hardy's hand.

The latter stepped toward the light and read it.  "Give any assistance
requested," it read.  "Thank goodness, that's settled," muttered
Captain Hardy.

Then he turned to the lieutenant, who was now more than ready to
oblige.  "Can't you get a little more speed out of her?" he demanded.

"I'll try," said the boat's commander, and he strode off to the engine
room.

Past the Brooklyn Bridge, past the Manhattan Bridge, past the Navy
Yard, past factories and offices and great rows of tenements, the
little police-boat sped on.  But the hands of Captain Hardy's watch
sped faster.  Past Blackwell's Island, with its long prison buildings,
past the little lighthouse at its northern end, past the darkened area
of the East River Park, on toward the blackness of Hell Gate with its
frightful swirling waters, rushed the speeding craft.  And now, drawn
by a common interest, boys and men alike crowded the bow, and policemen
and scouts stood in a close knot, gazing eagerly ahead into the
darkness.

A motor-boat suddenly shot across the path of the Patrol.  "Halt!"
cried Lieutenant Gavigan, seizing a megaphone.  The motor-boat came to.
Lieutenant Gavigan was about to stop to examine it.

"Go on," said Captain Hardy tensely.  "That's not the boat--and there's
only one man in it anyway.  We're after a gang."

Darker became the way.  The river broadened.  The waters grew troubled.
High above loomed the great arch of the new railroad bridge over Hell
Gate.  A sailing craft drifted silently toward them.  Lieutenant
Gavigan looked questioningly toward Captain Hardy.  The latter shook
his head.

Again he drew forth his watch and held it close to his face.  "Nine
ten," he said, in a voice that shook with emotion.

On rushed the little steamer.  It began to turn its nose toward the
wicked waters that gave the region its name.  Then it ploughed into the
swirls and headed for the smooth reaches beyond.  No craft of any sort
could be seen.

"We'll have to go through," said the lieutenant.  "We can't turn here."

The boat passed under the great bridge and on through the seething
rapids.  It ran on for a little distance, then circled and swung back.
Again it passed through the angry waters, then made a wide circuit,
steaming slowly along the land, while those aboard searched the
darkness, peering into every curve and indentation of the shore, to try
to spy out some sign of life.  Tugs were shunting car barges, and an
occasional steam craft passed, but nowhere was there a sign of a
motor-boat or of the fugitive Germans.

A great doubt came into Captain Hardy's mind.  Could it be that after
all they had been on a wild-goose chase?  He had thought the connection
between Hell Gate and the Balaklavan rendezvous far-fetched.  But it
had been the one chance left.  They had tried the theory out and they
were wrong.  The wireless patrol had not merely lost the Germans.  They
had lost all trace of them.  They had failed in the crisis.




CHAPTER XX

A CLUE FROM THE AIR

Slowly the little police-boat finished her circuit, nosing into every
dark nook and spying out every black corner; but blacker than either
the night or the water was the gloom in the hearts of Captain Hardy and
his fellow members of the wireless patrol.  With bowed head the
disappointed leader turned to the commander of the boat, to tell him to
return to his dock.  But Captain Hardy was too loyal to his fellows,
too resentful of Lieutenant Gavigan's remarks about them to indicate by
word or act that he thought they had been on a wild-goose chase.  So he
said simply, "We were too late, Lieutenant.  They have given us the
slip.  But none the less I thank you for your assistance."

Then he turned aside and stood peering gloomily into the dark waters,
that reflected the exact shade of his own mind.  Appreciating better
than his youthful companions the full extent of the disaster that had
befallen them, he could not, for the time being, summon up his usual
fortitude or see any hopeful prospect.  Now that the spies knew that
they were discovered, he felt sure that they would never risk the
sending of another wireless message.  And a wireless message was the
sole clue by which his little patrol might once more pick up the trail
of the fugitives.

But Captain Hardy's disappointment was no whit keener than that of his
fellows, nor his sufferings any more poignant; yet with the buoyancy of
inexperienced youth, hope was not entirely crushed in the heart of any
one of the young scouts.  So absolute was their faith in their leader,
so astonishing had been the good fortune that so far had attended their
efforts, that each felt that in some way this present disaster would
yet be retrieved.  And with hope as a motive power, each began, in a
manner true to his character, to attack the problem that confronted
them, to get ready for further service.  It was a splendid example of
the spirit of "never say die" that their leader had drilled into
them--an example that he would be quick to follow, once the shock of
disappointment had passed away.

Lew, hopeless of solving the puzzle of the spies' disappearance, was
thinking of how the scouts should equip themselves if they should be
called upon for a land pursuit; for at following trails and taking care
of himself in the open he had no superior in the wireless patrol.  Roy,
keen minded as a Sherlock Holmes, was turning over in his mind the
problem of the spies' escape, trying to reason out what their line of
action would be in the immediate future.  Willie was examining a mental
landscape to decide the same question.  With that wonderful facility of
memory he had acquired by hours of practice at Camp Brady, he now
called up the maps of the neighboring waters he had been studying; and
in his mind's eye he could see every point and indentation of the
shore-lines, every arm of water, every inequality of the land as
pictured on the contour map, and the principal roads of the region.
And he was asking himself what a party of fugitives in a small boat
would naturally do.

Henry, eager as always to learn more about the wireless, had
ingratiated himself with the _Patrol's_ wireless man and was eagerly
examining his instruments and plying him with questions.  At first the
operator answered with good-natured tolerance as one replies to the
queries of a child.  But when he saw how much Henry actually knew, and
found that though he was only a boy he had already acted as operator at
a government wireless station, he fell into an earnest discussion about
the possibilities of wireless in police work--for in New York the
police wireless was still in an experimental stage.  Then he permitted
Henry to clamp on the receivers and listen in.

Henry welcomed the opportunity, for in all the weeks they had been
watching the Germans, the wireless patrol had hardly had an opportunity
to listen to the myriad voices in the air.  They had had to shut out
all other sounds and tune down to the low lengths used by the
Germans--and by nobody else.  They had been like spectators at the
opera with their ears plugged to shut out the music.

Now, as Henry eagerly listened in, he caught a sharp, whining note that
vibrated powerfully in his ear.  "There's the Navy Yard calling," he
said, and a deep frown passed over his face, for it made him think of
submarines and the failure of the wireless patrol.  For a moment he
tuned to a short length and listened for a spy message, as he had done
so many times before.

"That's the Waldorf-Astoria talking," said Henry a moment later, and he
copied down the message and shoved it over to the police operator.

Then followed press despatches--stories of land and sea, of fires and
battles, of shipwrecks and the arrest of a spy.  And again Henry
scowled and slid his tuning-coil and briefly listened in at lower range.

Down the river ploughed the little steamer, repassing, one by one, the
landmarks it had passed on its trip northward.  As it steamed along and
the meaning of their failure became more apparent to the young scouts,
they became gloomier and gloomier.  But Henry, exulting at the
opportunity to handle such an outfit, almost forgot their failure, and
drank in eagerly the gossip of the night.  So engrossed was he, that he
was startled when he heard the order to slacken speed, and heard his
captain say, "Well, here we are, boys."

Reluctantly he removed the receivers.  Then, as an after-thought struck
him, he clamped them again to his ears, tuned his coil to a low length,
and strained his ears in one last search for a forbidden voice in the
dark.  For a moment he sat listening vainly.  Then, with unwilling
fingers, he began to take the clamps from his head.  But suddenly he
jammed the receivers back on his ears and sat tense.

"Hurry up, Henry," called Captain Hardy.  "We're waiting for you."

"Hush!" said Henry, lifting a warning hand.  Then he sat rigid, bending
eagerly forward.  In his ear a call was sounding.  It was the old
familiar call of the motor station.  He seized a pencil and began to
write.  A moment later he jumped to his feet and went rushing after his
captain.

"Here!" he called, thrusting a paper into Captain Hardy's hand.  "The
motor-car station just sent this message."

"The motor-car station!" exclaimed Captain Hardy, in astonishment.
"Then Sanders can't be aboard the motor-boat.  The Chief said he had
him covered so closely that he could not escape--and evidently he
couldn't."  A moment later Captain Hardy stood frowning, trying to
puzzle out the meaning of it.  "I don't see how he could have sent a
message," he continued, "if he is so closely watched that he couldn't
get away."

"Perhaps the message will tell us," suggested Roy.

"Right again, Roy," said Captain Hardy.  "We'll hurry to the office and
decipher it."

On the run they made their way to the subway station at Bowling Green.
They caught a north bound train and shortly afterward swarmed up out of
the subway and made a rush for the secret service offices.

With hardly more than a word of greeting they drew up at a table and
laid the paper with the message before them.

"Forty," said Captain Hardy, counting the letters.  "If they use the
same cipher they did last time, that'll make five columns of eight
letters each."  Rapidly he set down the letters in the order indicated,
thus:

  T T E N R
  H A S E Y
  G Y U R A
  I L O E B
  N T V R O
  D C Z E H
  I A E V C
  M X D E E

Then slowly he read off the message:
"ECHO--BAY--REVERE--RENDEZVOUS--EXACTLY--AT--MIDNIGHT."

With a cry of joy Captain Hardy leaped to his feet.  "We've got another
chance," he said.  "Sanders must be going to meet them at Revere
Rendezvous--wherever that is."  Then, turning to a man at the next
desk, he inquired, "Where is Echo Bay?"

"At New Rochelle," said the agent.  "That's where Fort Slocum is."

"Fort Slocum!" cried Captain Hardy.  "This may be even more serious
than it seems.  Can this man be spying on the fort, too?  How far is
New Rochelle from here?"

"Eighteen or twenty miles."

"Can we get there by twelve o'clock?"

"Sure.  Why?"

"The spies we are after are to meet at Echo Bay, Revere Rendezvous, at
midnight.  Are you sure that we can get there?"  Then he glanced at his
watch.  "It's already long past ten."

The Chief was still at the office.  The agent went to consult him, and
came back for details.  Captain Hardy stepped into the Chief's private
office and made the entire situation plain.  The Chief sat like a cake
of ice, a thinking machine immovable and unmoved, listening to the
recital.

"How many men have you here?" he asked his subordinate, the instant
Captain Hardy had done talking.

"Four."

"Two of you go by automobile, two by motorboat.  Divide these boys and
take half with each party.  Let those who go by land approach the
meeting-place on foot and hide.  The motorboat must come in behind the
spy boat and cut off retreat.  Be sure you are armed."




CHAPTER XXI

THE CAPTURE OF THE SPIES

Without a moment's delay the party that was to go by boat, including
Henry and Roy, rushed off to the dock where the secret service had a
motor craft of the racing type, capable of making tremendous speed.
Almost as quickly the other party found itself seated in a powerful
touring-car, speeding northward.  Captain Hardy, Willie, and Lew were
in the car, together with the two agents and the driver, who was
likewise a secret service man.

Up Third Avenue rolled the big automobile, dodging wagons, shooting
past motor-cars, darting by trolleys, its horn shrieking an almost
unceasing warning as it charged onward at the very top of the speed
limit.  Never had Willie or Lew ridden so fast in crowded
thoroughfares, and time and again they held their breath as the big car
rushed toward some obstacle in its path, expecting a crash.  But under
the skilled hands of the driver the great machine swept in and out,
weaving its way through the traffic as an eel glides through water
growths.

The first thrill passed, they turned to their captain and the secret
service agents who were earnestly discussing the situation.  Overhead
the thunder of the elevated trains was such that at times they could
hardly hear what the men beside them were saying.

"I am well acquainted with New Rochelle and the region of Echo Bay,"
said one of the agents, "but I never heard of any Revere Rendezvous
there.  However, the people of the town can doubtless tell us.  We
shall have time to make inquiries."  And turning to the driver, he
said, "Shove her to the limit, Jim."

Already the car was well up-town.  Traffic had grown steadily less, and
as steadily the driver increased his speed.  Now they were rolling over
the smooth asphalt at twenty miles an hour.

"No doubt they could tell us," replied Captain Hardy, "if there were
any such place.  But I fear that the name is one of the spies' own
making," and he told the story of the Balaklavan rendezvous.  "We think
that meant Hell Gate," explained Captain Hardy.  "The fact that the
spies' motor-boat is now evidently on the Sound confirms that belief.
But the name was far-fetched.  It took us a long time to work it out.
This new name may be equally obscure.  We shall have to decipher it on
the way."

The motor-car was approaching the Harlem River.  "Your Balaklavan
rendezvous is only a few blocks off there," said the agent, pointing to
the east.

The car rolled up to the bridge and passed over the dark waters where
tugs were shunting car-floats into their docks and churning up white
foam with their propellers.  Thousands of lights were reflected in the
black depths.  In a moment the Harlem was behind them, and they were in
the borough of the Bronx.  On they sped up Third Avenue.

The two boys were distracted.  They wanted to see the sights, utterly
new to them, and they wanted to hear the discussion of their elders.
Willie, with that strange faculty of his for noting places and
locations, kept watching the street signs and trying to remember where
Third Avenue led to on the map.

"There are three places on Echo Bay where a motor-boat and a motor-car
can easily meet," said one of the secret service men.  "At the north
side of the harbor entrance is a finger of land called Premium Point.
On the other shore is Huguenot Park.  And an arm of the bay runs inland
all the way to the main street passing north through the town."

"Which place would they be most likely to select?" asked Captain Hardy.

"Well, they'd hardly try Premium Point because that is a private
estate, and they would have difficulty in getting to the water-front."

"Then that limits them to the two others."

"Exactly.  And one is as easy to get to as the other."

Captain Hardy frowned.  "What are we going to do?" he asked.  "We might
pick the wrong place and miss them.  And since there are several of
these spies in the boat, and they are desperate fellows, we'd never
dare divide our forces.  What are we going to do?"

"Gee!" said Willie.  "We just passed Two Hundredth Street.  Some town,
eh, with two hundred numbered streets?"

The car rushed on.  In silence the three men were considering how they
should meet the situation before them.

"If only we could get into touch with our motor-boat," said one of the
secret service men, "we could arrange a plan to cover every
possibility."

"We've got to find what this Revere Rendezvous is," insisted Captain
Hardy.  "Can't you think of anything that would suggest such a name?"

The three men fell silent, pondering the matter.  The car swept on.

"Hello!" said Willie.  "We've left Third Avenue, but we're going so
fast now I can't make out the names on the sign-posts."

And indeed they were going.  As they approached the edge of the city
limits, where there was little traffic and the driver could see far
ahead, he pressed his foot on the accelerator and the great car went
roaring through the street at more than thirty miles an hour.  And as
they drew closer and closer to the open country, the man at the wheel
rushed them on faster and faster.  In vain Willie looked at the
sign-posts.  The car darted past them with baffling speed.  But Willie
wanted to know where he was.

"What street are we on now?" he asked, leaning toward the driver.

"The Boston Post Road," said the driver, without turning his head.

Captain Hardy caught the name and his eyes flashed.  "The Boston Post
Road!" he repeated.  "Does this go anywhere near New Rochelle?"

"Right through it," said the driver, "only they call it Main Street
within the town limits."

"Does it pass near Echo Bay?"

"It's the very road that meets the arm of the bay."

Captain Hardy turned from the driver to the other secret service men.
"Can you think of anything that would connect the name of Revere with
the point where the bay touches this road?"

"By George!" cried one of the men.  "You've hit it exactly.  I had
forgotten all about it, but there's a stone marker in a wee bit of a
park, put up to commemorate the passage of Paul Revere on his famous
ride.  He came down this very road, and that marker is almost at the
exact spot where the road touches the arm of the bay."

"Good!" said the captain.  "That is probably the place."

"Beyond a doubt.  It's the logical place, too, come to think of it.
For if a fellow drove into Huguenot Park and found that somebody was
trailing him, he couldn't get away.  He'd be bottled up.  But if he
stuck to the Boston Post Road, he'd have all New England to run to.
What's more, there's a road-house near by, where cars can be left.
Things couldn't have been made to order any better."

"Then I guess our course is clear," said the other agent.  "We'll leave
our car near by and find good hiding-places close to the water at this
point."

Meantime, the motor-boat, breasting the waves as though striving for a
speed prize, had borne Henry and Roy and their older companions rapidly
back over the path they had so recently traversed.  Up the East River
the craft went roaring, under the great bridges, that at night seemed
only strings of fairy lights arching the stream, past prison walls and
towering tenements, and on to the swirling rapids so recently visited.

The two boys paid little attention to what they were passing.  Already
they had seen it twice.  But never had either of them seen a craft like
that they were in.  It was one of those long, low racing boats, steered
with a wheel like a motor-car, and slopingly decked over in front to
shield the driver.  And it roared like an aeroplane as it tore through
the water.  For the boys in the boat were rushing toward their goal
almost as swiftly as their comrades on land.

What most interested Henry and Roy was the array of buttons and knobs
and other instruments on the dashboard, like the lighting buttons and
speedometer on an automobile.

"I wonder what they are for," said Roy to Henry.  "I never saw a boat
like this before."

"Nor I, either," replied Henry.

"Right you are," said one of their companions.  "There probably isn't
another like it.  It's both a motor-boat and an electric boat.
Sometimes we have to be very quiet about our work and then we would
never dare go roaring along as we are now.  You can hear us a mile
away.  So we have an electric motor and storage batteries for quiet
work.  When we run by electricity, we don't make any more noise than a
swan."

The boys expressed their admiration.  "And nobody could see you,
either," said Roy.  "The boat's exactly the color of the water.  When
it's as dark as this, I'll bet you couldn't see it fifty yards away."

"Well, you may have a chance to test your belief," said the agent with
a smile.

"What do you think will happen?" asked Roy.

"I don't know.  But when that German motor-boat goes into Echo Bay,
we've got to go after it; and we don't dare be seen, either."

"What's the bay like?" inquired Henry.

"It's an irregular little sheet of water with several small islands in
it; and if these Germans go clear in, we'll nab them easily.  But if
they don't, we may have a lively chase."

On rushed the motor-boat.  Past Classon Point, past the long projecting
finger of land known as Throgs Neck, with Fort Schuyler at its
extremity, then northward again into ever widening waters, past Elm
Point, and Hewlett Point, and Barker Point until they were fairly in
the wider reaches of Long Island Sound.

On the right loomed the high and precipitous shores of Long Island,
hardly visible in the cloudy darkness.  On the left, far across the
waving waters, was the unseen ragged coast of the mainland, broken by a
hundred irregular indentations, studded with numberless little
promontories, and fringed with islands as a woman's throat is girt with
a necklace of beads.  Ahead of them stretched untold miles of gently
heaving water.  And there, too, blazed two beacons to point the path
for mariners--the Sands Point Light, topping the eastern bluff, and the
fiery eye of Execution Rocks, that reared their jagged pinnacles far
out from the shore, to tear the bottoms of unwary ships.

"We'll go straight north," said the man at the wheel, "for those spies
are without doubt biding their time in some sheltering cove among the
islands over there.  And there they will doubtless stay until the hour
to meet their comrade."

He flashed a pocket torch on his watch.  "We are in good time," he
said.  "We shall get there well before them.  Then we shall have to
hide and see what happens."

Straight up the Sound drove the rushing racer, plunging through the
rolling swells, tossing the spray to right and left.  Ahead of it
glowed and winked the fiery eyes of the lighthouses.  Along either
shore shone innumerable street lamps and the lights of late retiring
householders.  Save for themselves the water seemed deserted.  The
great steamers that ply between New England and the metropolis had long
since passed and vanished in the misty darkness to the north.  No
freighters were breasting the waves, no tugs were puffing along with
strings of barges in their rear.  No ferry-boats were crossing.  And
none of the legion of sailing craft and motor-boats, none of the
thousands of pleasure yachts that sometimes dot the smiling waters in
the daytime, was abroad.  The little secret-service boat seemed to be
alone in that vast expanse of water.

Suddenly the boat careened violently.  The boys were alarmed, but their
comrades merely smiled.

"We're turning," explained the man at the wheel.  "Now we'll go
straight into the harbor.  And it will be just as well if we make less
noise."

He slowed down his engine and the roaring sound died away.  The boat
fell off in speed, but still pushed ahead with good momentum.  For
perhaps a mile the boat advanced.  Then the driver shut off his engine
entirely.

"Those fellows might be in Echo Bay itself," he said.  "They couldn't
find a safer place to hide than right among the pleasure craft.  We
won't take any chance of being discovered.  We'll just glide in like a
shadow and anchor where we can watch things."

He switched over to his electric drive and the boat began to forge
ahead again, but with all the stealth of a tiger in the jungle.  The
operation of its machinery was noiseless, and only the gentle slap of
the waves against the bow gave audible evidence of its passage.  For a
considerable time they rode in silence.  In the thick darkness the
shore was almost invisible while the glowing street lights that shone
here and there served only to accentuate the blackness of the night.
Close together in the cockpit huddled the passengers, for the air was
raw and chilly.

"Until we've got those fellows safe in handcuffs," said the man in
charge of the party, "I don't want one of you to speak aloud.  And stay
down in the bottom of the boat where you can't be seen."

Noticeably the speed of the little craft fell off, It no longer drove
through the waves, but slipped through them so softly that even the
gentle splashing at the bow was ended.  Presently Henry missed the
slight vibration, of which he had been but semi-conscious, and he knew
that the pilot had shut off his power completely.

Now the shores, with their towering trees, began to loom up uncertainly
in the darkness, and Henry knew that the boat was slipping into the
harbor.  Presently he became aware of a dark spot ahead of them on the
water, then another, and another; and straining his eyes, he saw that
before them lay a great company of motor-boats and sailing yachts.
Very slowly his own craft drew nearer, for it had all but lost its
headway, until it was close to the fleet of pleasure boats.  Then there
was a tiny splash and one of the secret service men began to pay out
the anchor rope over the side.  The little boat came to rest, and lay
quiet, rolling gently, while its occupants crouched in the cockpit,
listening and peering through the thick darkness as they waited.

Never had either of the boys been in such a situation before, and the
strangeness, the mysteriousness of it impressed them powerfully.  All
the sights and sounds of the day were missing and in their place arose
a host of unfamiliar sensations.  Mist was rising all about them,
making the darkness denser and more impenetrable.  Not a star was to be
seen.  The shore-line was only a vague, uncertain black bulk.  As they
huddled silently in the bottom of the little boat, they became
conscious of the voices of the night; but these voices were different
from the nocturnal whisperings of field and forest which they knew so
well.  Now they heard only the lisping of water.  Little wavelets broke
gently against their slender craft.  And all about them rose the
musical whisper, the liquid murmur of waters gently lapping the rocks
or swelling against the sides of boats.  At times the breeze could be
heard sighing softly through the rigging of near-by yachts.  It was
weird and uncanny.

And the sensations that came of it were strange and powerful.  In the
forest the young scouts had lain in wait for enemies, had hidden in the
darkness to trap desperate foes, had watched, with bated breath and
pounding hearts, for shadowy forms to appear.  They were not
unaccustomed to danger and the suspense of an ambush.  But in the
forest they had solid ground beneath their feet.  Trees and other
tangible objects were all about them.  But here everything seemed
unreal, almost ghostly.  The darkness of the forest was no blacker than
the night here in the open.  And yet there was no shady covering of
leaves to shut out the light--only a strange, weird, unearthly canopy
of mist.  In the forest innumerable tree trunks offered concealment to
approaching enemies; yet here in the open with nothing tangible to
obstruct the vision, it was almost impossible to see anything, strain
the eyes as one might.

A feeling of awe came over the young scouts, and both were conscious of
a creepy sensation.  So unreal appeared their surroundings that it
seemed as though anything coming out of the mist would be kin to it,
unreal and ghostly.  So they sat in the bottom of the boat, only the
tops of their heads showing above the low gunwale, as they waited in
breathless silence, peering through the night, listening with cocked
ear, and straining forward to catch every slightest sound.

Under the covered bow of the boat, the driver flashed his torch for a
second on the face of his watch.

"Eleven forty-five," he muttered.  "There ought to be something doing
soon."

A minute passed.  The silence was unbroken.  Another minute went by.
The sighing of the wind in near-by riggings was the only audible sound.
Again a minute passed.  No sound of boat or boatmen broke the gloomy
silence.  Once more the pilot peeped stealthily at his watch and gave a
muttered exclamation.  A feeling of uneasiness took possession of the
watchers.  They stirred nervously.  Dark fears crept into their minds.
Had something happened to alter the plans of the spies?  Had Sanders
sent another wireless message to his comrades, naming another
meeting-place?  Henry's heart almost stopped beating at the thought
that it might well have happened.  Bending toward his comrade, he
whispered his fears.  His voice trembled as he spoke.  Roy uttered a
low exclamation of dismay.  Then there was silence again, and the four
sat listening with strained attention--listening for what they feared
they would never hear.

And then they heard it.  From far down the Sound came the reports of a
rapidly beating marine motor.  At first the noise was so faint as
scarcely to be audible, like the dropping of a pin on a bare floor.
Then the fog seemed to magnify the sound and it became suddenly louder.
Then it died away again, but it was more distinct than it had been at
first.  A minute passed.  Noticeably the sound grew in volume.  Another
minute passed.   Distinct now was every beat of the motor.  With lips
parted, heads slightly turned, and eyes peering through the dark, the
watchers waited with beating pulses as the sound came on.  There could
be no doubt it was made by a fast craft.  And there could be no doubt
that the boat was rushing northward close to the shore.  Was it the
boat they waited for?  Would it turn at the harbor entrance?  Or would
it go tearing onward, leaving them in despair?

Now it was almost abreast of the harbor's mouth.  Another minute, a few
seconds, would tell the story.  And not one of the watchers breathed as
they hung on the sound.  On and on it came, until the scouts knew that
it was directly abreast of the channel.  Would it turn?  Would it enter
the harbor?  Or would it rush straight by?  Unable longer to control
himself, Roy stretched out his hand and gripped Henry's shoulder.  And
Henry, like himself, was all atremble.  The secret service men stirred
nervously.  But nobody said a word.

Then the passage of the sound seemed to end.  It was no longer rushing
by.  It seemed stationary.  But momentarily it grew in volume.  It was
coming straight toward the watchers.  The boat had entered the harbor.
A sigh of relief escaped every lip.

"Up with your anchor," whispered the pilot, "before he shuts off his
power."

His companion leaned stealthily over the side and rapidly paid in the
rope, lifting the light anchor over the gunwale and cautiously stowing
it in the bottom.  And he was none too soon.  Hardly was the anchor
aboard before the roaring sound ceased and the oncoming boat approached
with lessened speed.  But the scouts' boat rode free, ready for instant
work.

"Down with you," whispered the pilot.  "Keep your heads below the
gunwale till they're past."

The party crouched lower.  On came the spy boat.  Its muffled engine
beats were hardly louder than the pounding of the hearts that watched.
It drove steadily forward.  Now it was a few fathoms astern.  Now it
was abreast.  Now it had passed.  Stealthily four heads slipped above
the gunwale of the scout boat.  The spy craft was already lost in
darkness.  The pilot grasped his wheel.  He turned a switch and the
boat began to vibrate silently.  Then it moved forward, gathering
momentum with every second.  Under the covered deck the other agent
flashed a light on his watch.

"Eleven fifty-eight," he whispered.  "They figured it down close."

On went the boat.  The craft ahead of them was still invisible though
but a few hundred feet distant.  But by peering sharply at the water,
the pilot could see where it had passed.  The surface was still
agitated.  Faintly came the sound of the muffled motor.  The pilot
increased his speed, but no sound came from his boat.  Like a ghost it
glided through the dark waters.

"Look sharp," whispered the pilot.  "Let me know if you see them.
We've got to get as close to them as we can, and yet we must not be
seen."

On went the spy craft.  It slid past the park.  The street leading to
that was faintly illumined by occasional lights.

The pilot uttered a low exclamation of alarm.  "If they look back," he
whispered, "those lights will betray us.  We're right between them and
the spies."

Sharply he swung his craft to the right, crowding close to the shallow
waters that edged the channel.  If he ran into the mud flats disaster
might result.  But to stay where they would be silhouetted against the
street lights was to court discovery.  He had chosen the lesser of two
evils.

On they went.  Not yet had they come in sight of the fugitive craft in
front of them.  The pilot increased his speed, leaning anxiously
forward as he peered through the darkness.  Over the sides of the boat
his fellows craned their necks, searching the blackness for a glimpse
of the quarry.

Suddenly they became aware that the motor ahead of them had stopped.
Then masses of shadow seemed to close in on either hand, making the
water itself darker than ever.  The boat ahead had turned off its power
and was propelled only by the momentum it had gained.  Instinctively
Roy laid his hand on the pilot's shoulder.  But the latter had already
stopped his engine.

As silent as a shadow the boat slid forward.  Suddenly Roy detected
what he was looking for.  At the same moment a high bank loomed up
directly before them.  The craft ahead turned toward the right and
slipped along the narrowing channel.  A few yards further on, it came
to rest, its nose lying softly against the muddy shore.  Before it the
steep bank led upward to an open, level space that both Roy and Henry
felt instinctively was a public highway; for on either hand, though at
many rods' distance, could be seen the glow of a lamp that was
invisible itself.

The scout boat also came to rest, its momentum overcome by the
resistance of the water.  Like a shadow it lay, not more than fifty
yards from the waiting spy craft.  Crouching low behind the gunwale,
its four occupants held their breath as they watched the party in the
boat ahead.  Assisted by the faint glow of the distant street lamps,
they could vaguely make out the forms of their quarry; while the
darkness of their own background rendered them practically invisible.

But no one in the spy boat was looking behind him.  All were straining
their eyes for the man they had come to meet.  Excepting for the gentle
voices of the night there was not a sound.  Then a whistle rose from
the spy boat--a short, sharp note thrice repeated.  From the darkness
an answer sounded a dozen rods distant.  Then footsteps were heard, as
some one picked his way uncertainly along the sloping bank.  Suddenly
the footsteps ceased and stillness reigned.  Roy instantly comprehended
the fact that the person approaching had paused to listen.  His heart
gave a leap of joy.  He himself had heard no alarming noises, but he
instantly guessed that something had caught the ear of the stranger.
And Roy knew that his companions who had come by motor-car must have
made these sounds.  Trembling with excitement, he gripped Henry's
shoulder.

On came the man.  Now the scouts could vaguely distinguish his form.
He called in a low voice, and some one in the spy boat answered.
Suddenly the man turned sharp about.  From the darkness behind him came
the unmistakable sound of a pebble kicked by a human foot.  In the
opposite direction a stone rolled down the bank and splashed noisily
into the water.  With an oath, the man on the bank turned and ran
toward the motor-boat.  To right and left in the darkness came the
scurrying of feet and the command "Halt!"  The fugitive leaped forward.
Frantically the men in the spy craft were trying to head their boat
about.  The fugitive reached it and leaped aboard.  Then he turned to
face the figures rushing toward him.  At the same instant the scout
boat suddenly moved forward.  From the spy boat a pistol-shot rang out.
Before another could follow, an electric torch was shining full on the
spy craft, and the agent in the scout boat was covering the fugitives
with his automatic.

"Drop that gun!" he commanded.  "Hands up, or I'll fire!"

Taken by surprise, the man who had just boarded the craft let his
weapon clatter to the floor.  And in the sudden illumination Henry saw
with exultation that the man was the motor-car driver, the German
agent, Sanders.

"Hands up!" repeated the secret service man imperatively, noticing that
one of the fugitives was crouching in the bottom of the boat with his
hands hidden.  In reply the man straightened up.  Like a flash his arm
shot out and a pistol cracked.  But before a second bullet could
follow, a form leaped into the shallow water and a great fist shot into
the man's stomach, doubling him up like a jack-knife.  The same hand
then grasped the nose of the spy craft and dragged it toward the shore,
while the pilot of the scout boat brought his craft close beside that
of the spies.  Other torches flashed in the darkness, and one by one
the fugitives were manacled--Sanders, and the spy from the cliff, and
the German grocer, and his errand boy, and a stranger who ran the boat.




CHAPTER XXII

A TASK ACCOMPLISHED

Two hours later the party was grouped around Chief Flynn, who had
remained in his office to learn the result of the raid.  Both
motor-boats had been left in charge of the New Rochelle road-house
keeper, and the entire party had returned to New York in the two
motor-cars--the secret service motor and Sanders' car, for Sanders had
left it at the road-house and slipped away into the darkness at
midnight.  The clerk from Hoboken was under arrest, too.  He had been
taken up by the man who was watching him.  Sanders had eluded his
shadow by leaving his car late in the afternoon, at a garage,
ostensibly to have it washed, and by later leaving his house
surreptitiously in the dark.  He had not been able to reach the
Balaklavan rendezvous in time to join his companions.  But they had a
wireless equipment aboard their boat and he had made a later
appointment with them.  And, even as Captain Hardy had suspected, he
had been nosing around Fort Slocum in the darkness.

But this was all the secret service ever learned as to the operations
of this gang of wireless spies.  The prisoners refused to name those
higher up, and the Chief could only guess whose might be the master
minds behind the plot.

As for the various wireless agents who were relaying the spy messages
to Mexico, several were caught by decoy messages and shared the fate of
Sanders and the others.

Even the mystery of the sudden flight of Sanders and his crew was
cleared up.  Following the Chief's orders, his men on the border had
taken the three silver coins away from the Mexican.  And, sure enough,
the coins contained messages.  One was the message from New York
concerning the sailing of transports.  The other messages were about
army secrets, and it is not yet known where they came from or how they
got into the hands of the Mexican.

The latter protested violently when asked for his silver dollars, and
they had to be taken from him by force.  The next day one of his guards
discovered that the left cuff of his shirt was missing.  The shirt had
been intact when he was arrested.  No trace of the cuff could be found
anywhere.  The window of the room where the Mexican was confined
overlooked a public street.  And it was believed by the secret service
men that the spy had written a message on his cuff in some way and
dropped it out of the window to a confederate.  Thereupon a warning had
been flashed back along the wireless line--a warning message in the new
cipher that had so puzzled the lads of the wireless patrol.

"It's all clear enough now," sighed Willie, when the story had been put
together, "but when you have only one piece of a jig-saw puzzle you
can't make much out of it.  And one piece was about all we had for a
long time.  I see it all now, but there's one thing I don't yet
understand.  Why didn't they use a more difficult cipher?"

"I suppose," explained the Chief, "that this very pursuit and capture
of the spies answers that question.  They knew that if the secret
service picked up their messages, we could sooner or later decipher
anything they sent.  But even a very simple cipher might baffle one
unaccustomed to such things.  Always there was the danger that some one
would pick up their messages.  So they chose ciphers that would bother
the ordinary man but that they themselves could read readily.  They
didn't dare use a cipher that would require a long time to unravel,
because they foresaw that they might have to flee on short notice, just
as it happened."

"I see," said Willie.

"And now," said the Chief, "I want to tell you boys and your good
leader here how much you have done for me and your country.  I didn't
have faith in your accomplishing much, but I thought that you might be
able to pick up wireless messages, if any were abroad, and so I agreed
to take you.  You see we were almost desperate over the situation.  We
knew what was going on, but we were so terribly short handed that we
could not spare men to run the spies down.  I think that we shall have
no more trouble.  The system is broken up.  If we do have trouble, I'm
going to send for you boys at once.  Meantime, you can now go back
home, knowing that few boys have done as much for America and Freedom
as you.  I am more grateful to you than I can tell you."

The little wireless patrol passed out into the night, its labors ended.
Now that the excitement was past, the boys realized how tired and
sleepy they were.  As they crossed the Bay to their temporary home on
Staten Island, they had their last view of the harbor.  Now it was
almost silent.  Only a few boats were ploughing through its waters.
The great office-buildings were dark.  The fiery lights of the city
were extinguished.  But bright above the Bay flamed the torch of
Liberty.  There, in that flickering light, was symbolized the thing
that millions of men were giving their lives to protect--the greatest
heritage of the ages.  And as the boys from Central City looked at the
symbolic illumination, their hearts beat exultantly and their eyes grew
dim with joy at the thought that they, too, had been able, through
months of self-denial and rigid self-discipline, to prepare themselves
for the task that was now so happily ended.