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 NI A O L T M IX N R E H O NT 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."
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:
"FTSTITEIAFTDLLTNSYWTORPSLHVNRLEEYLIOTEIHUAOSEIEGGEVNCENDRRTERNRADSNLEEITOCGEOSHM."
"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:
FTSTITEIAFTDLLTNSYWTORPSLHVNRLEEYLIOTEIHUAOSEIEGGEVNCENDRRTERNRADSNLEEITOCGEOSHM
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."
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 wastheview-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."