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."