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Title: The Secret Wireless
       or, The Spy Hunt of the Camp Brady Patrol


Author: Lewis E. Theiss



Release Date: June 28, 2007  [eBook #21955]

Language: English

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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