It was characteristic of Henry that he should tell the worst about himself first. In his own manly way he was willing to accept the blame for his failure.
"He got away from me," he began, so chagrined that he could hardly repress the tears. "I didn't find the hidden wireless and I have failed in my task."
Before his captain he stood with downcast eyes and tortured heart. His experience at Camp Brady had taught him that the wireless patrol expected every member to do his duty—and he had failed.
Captain Hardy looked at his lieutenant for a moment without answering. He had not the slightest idea of what had occurred, but he recognized instantly the manliness of Henry's report. The latter was offering no excuses, making no attempt to shield himself from the consequences of his failure.
"Suppose you tell us just what happened," said the leader gently, "and we can judge better how badly you have failed."
Gratefully Henry looked up. He had not expected a scolding. That was not Captain Hardy's way of disciplining his boys. But he had felt sure his leader would show how deeply he was disappointed, for Captain Hardy was terribly in earnest in this quest for spies. So once again Henry's heart went out to his captain. Rapidly he related what had befallen him. As he proceeded with his story, his leader's face lost its look of grave concern, his eyes began to flash with interest, his cheeks to burn with eagerness. When Henry's narrative had reached the point where the motor-car had disappeared in the field and Henry was searching for it. Captain Hardy held up his hand.
"Stop a moment," he interrupted. "You were in no wise to blame for what happened, and instead of being condemned for failure you are to be commended for your success. Many a boy would never have found where that car went. And even though you did not learn exactly where the car was, you have located the field and you may be sure that driver never went very far in a field. We shall find the place easily enough. Go on."
Henry looked at his leader gratefully and a happy light came into his eyes. "Do you really think I didn't fail?" he asked eagerly.
"Assuredly," insisted Captain Hardy. "I think that you have learned enough to enable us to locate this hidden station. Go on."
Henry proceeded with the story of his search in the dark, of his uncertainty as to what he should do, of his fear of missing the message as well as the car, and of how he had intercepted that message, marked the fence post, and located the home of the automobile driver.
"Why, Henry," cried Captain Hardy, when the recital was ended, "whatever put it into your head that you had failed? You have done well—exceedingly well."
"But I didn't find the hidden station, and you said that was so important."
"That is a mere detail, Henry. We shall find it easily enough. We have our experience at Elk City to direct us."
"That's just why I felt so bad," said Henry. "If these Germans have concealed their wireless plant as skilfully as the dynamiters did at Elk City, we may never find where it is."
"We'll try before we give up hope," said the captain smiling. "And even if we never find it, we now know something more important than the location of one of their several wireless plants. We know where another member of the gang lives. That is excellent, Henry, excellent! The Chief will be more than pleased. I know he is a great deal more concerned about this wireless situation than he permits us to think. The public is clamoring for protection for the troops and the Chief simply cannot accomplish one-fourth of what is demanded of him. If we uncover this gang for him, we shall do a very real service to America, boys."
"We'll do it," cried Willie vehemently. "We'll do it. We'll get 'em just as sure as we got the dynamiters."
"I believe we shall," smiled the captain. "And if that's the way you all feel about it, I know we shall. We're closing in on them fast. To-morrow we'll go out to that field Henry has marked and see what we can find in the daylight."
So it happened that the succeeding forenoon found the five members of the wireless patrol rolling rapidly toward the point of investigation, in a motor-car furnished by the secret service and driven by one of its agents. Henry sat beside the driver and pointed out the way, while the others crowded into the rear of the car.
With his map on his knees Henry traced the way. Speedily they passed through the built-up portion of Brooklyn and came shortly to the sparsely settled district through which their road ran. Henry scanned the way with curious interest. He had been over the road but he knew nothing of what he had passed. Occasionally they whirled by a tree close to the road that Henry thought he had glimpsed in the darkness. So they flew forward until Henry, looking eagerly ahead, cried out, "There are the lumber piles."
The driver slowed his car almost to a walk and they looked in the dust for telltale marks. Few teams had passed since Henry's adventure, and in the dust could still plainly be seen the marks of Henry's wheel as he had turned sharply into the field, and the narrow tracks of the vehicle that had almost run him down.
But Henry was more interested in marks of another sort. "There!" he cried suddenly. "See those tracks? They're the marks of the spy's roadster." And he pointed to parallel tread marks, one made by a chain tread tire and one by a diamond tread.
They passed on. Not many hundred yards distant was an opening in the fence. "That's the place he turned off," insisted Henry. "See that light place where I shaved the post?"
But they did not turn into the field. Instead the motor-car continued steadily on its way. A half mile up the highway was a road-house known to the driver.
"It's about eleven o'clock now," said the secret service man. "We'll have luncheon at the roadhouse and in the meantime we can stroll around and hunt up this wireless plant. We'd attract too much attention if we drove directly into the field."
They stopped at the road-house, ordered luncheon, and said they would stroll about until noon. Then they wandered, apparently aimlessly, about the place and into the fields. The country was nearly level, with slight depressions here and little hillocks there, and bits of woodland all about. The road-house was the only structure in sight, and when they had passed beyond a slight elevation, even this was hidden. Apparently there was not a soul in the neighborhood. They paused just inside a little grove and made sure that no one was following them from the road-house. Then they pushed rapidly on into the little thicket which Henry recognized as his hiding-place of the previous night.
After a moment's search, Henry found the mark he had made in the turf. "The motor-car was in that direction," he explained, pointing along his turf mark.
His fellows looked in the direction of his outstretched arm. At a distance of a quarter of a mile was a thick little grove. Henry was pointing straight at the heart of it.
The scouts had kept themselves well hidden in the thicket as Henry was finding his mark. If any one was in the wood, that person could not as yet see them.
"I have no doubt we shall find the secret station in that grove," said Captain Hardy. "I see several tall trees sticking up above the others that might conceal aerials. I doubt if any one is there now, but some one might be. So we shall have to approach carefully and in such a way that we can capture any one who might be within the grove. Suppose we advance on it from all four sides, as we did on the willow copse at the Elk City reservoir. Then if any one is within the grove we shall see him."
The leader gave each boy his orders and the advance began. Henry was to circle and enter the woods from the rear. Roy was to approach from one side and Willie from the other. Lew was to go in at the front. Captain Hardy and the secret service man were to station themselves outside the wood so that they could see every point of its exterior and detect any one leaving it. Each glided away toward his post.
At a given signal from Captain Hardy, the boys began to work their way silently from their posts into the grove. This was small in extent and such precautions seemed almost unnecessary. But after their desperate experience with the dynamiters, the members of the wireless patrol were taking no chances. They knew full well that discretion is the better part of valor. And they knew, in addition, that the success of their search might depend upon the caution with which they proceeded. So they went forward, when the captain's signal rang out, like so many Indians on the war-path, stalking a hated enemy.
Indeed they were almost as invisible as Indians. Each had circled skilfully to his post. And now each crept forward silently, slipping from rock to bush, taking advantage of the slightest cover, and advancing so stealthily through the tall grass that even the two men on watch outside the grove could hardly tell where the scouts were moving. And any one inside the grove could not have detected them at all.
The four scouts reached the four sides of the grove almost simultaneously. Each of the four crept round the trunk of a big tree and squatted down with the trunk at his back, to look and to listen. From side to side their eyes roved, examining every tree and stump in sight. But they saw nothing on the ground or in the branches overhead to alarm them. There was no indication of human presence other than their own; and Willie was certain that the wood was deserted, for several small flocks of birds flew up in alarm as he penetrated the grove. Had other men been within the wood, he knew the birds would long ago have been frightened away.
Slowly the four scouts worked their way toward the centre of the grove, gliding round the trunks of trees and stopping every few feet to look and listen. But they heard nothing, saw nothing, to indicate that any man was within the grove. Each one, as he advanced, scouted to right and left of his line of march, so that when the four met in the centre of the wood, they had covered every rod of ground within the grove. And they had found nobody.
What was more, they had seen no signs of a wireless outfit. But, in view of their experience in searching for the dynamiters' hidden wireless, this was not surprising. None of the scouts had expected to find the secret plant without a thorough search. As soon as Captain Hardy and the secret service man joined them, a systematic search of the wood was begun.
There could not have been more than two hundred trees in the little grove. Satisfied that the place contained no enemy agents, Captain Hardy took his company to one end of the ground and began a careful examination of each tree. The six searchers strung out in a line across the grove, testing each tree as they advanced. They scanned the trunks and thumped them with clubs to make sure that they were not hollow. They peered at them from all sides, looking for holes and hollow limbs. With sticks they scratched away the leaves from about the bases of the trees, turning up the soil for several inches and testing it for hidden wires. All the trees seemed sound. No hollow limbs were discovered. No suspicious marks were found in the earth about the tree trunks. The tall trees noted by Captain Hardy seemed never to have been touched by man. From tree to tree the search proceeded until every tree in the grove had been tested and the scouts were on the far edge of the wood. But no hidden wire, no secret instruments, no skilfully concealed aerials were found.
Blankly the searchers looked at one another. "It must be here," said Henry. "I am absolutely certain that the motor-car came from this direction and was about this distance from where I stood. And the signals were so loud and clear that I'm just sure they were sent from some spot close by."
"Let us look for wheel tracks," suggested Captain Hardy. "If we can find where the car stopped, we shall know that the message was sent from some point near by. Search along the sides of the grove first."
The party divided, and three searchers examined the ground along each side of the grove. Walking abreast and several feet distant from one another, they covered a broad strip of ground. Twice each party retraced its tracks but found nothing.
"Try another strip, farther away from the grove," said Captain Hardy.
Again the searchers lined up and went slowly forward on either side of the woods. Bending low, stepping slowly, sometimes kneeling to examine a suspicious mark, they moved carefully on. The thick turf had taken no telltale imprint.
"I fear it's useless," sighed the leader.
"Let's try again," pleaded Willie. "The car was here. We know that. And somewhere it was bound to make a mark. It might have gone beyond the grove."
They made another search, this time extending their examination to the land beyond the wood. Suddenly Roy gave a cry. "Here it is," he called.
The others ran to him. And there, sure enough, in a little bare spot between two hummocks of grass, was the plain imprint of a diamond tread. Instantly Roy and Willie dropped to their knees and began to feel along the line of the tire mark.
Henry and Lew, meantime, searched to right and left of them. "Here's his other wheel track," suddenly cried Lew, and there, sure enough, was a distinct impression of a chain tread tire.
They proceeded in the direction in which the car had been moving. "Here's where he turned," cried Henry.
The turf before him was torn and ragged. Distinctly they could see the impression made by the driving wheels as they gripped the ground in starting.
"Then here is where he stood," said Captain Hardy. "It is immediately behind the wood. Your mark pointed straight enough, Henry, but your man was farther away than you thought. Probably he ran behind this grove to make doubly sure he would not be seen from the highway. The hidden station must be in this end of the grove. We'll search again."
Once more they plunged into the wood. Again they examined every tree. Up one trunk after another shinned Roy and Lew, who were born climbers. But hunt as they would, search as they might, they found nothing to indicate a secret wireless. At last, completely baffled, they gave up the search.
"It's here," insisted Captain Hardy. "Our experience at the Elk City reservoir makes me sure of that. They're too clever for us. But we'll get them yet. We'll follow that roadster so closely next time that we can't miss the secret. It's too bad, boys, but don't be discouraged. We have done much to come so close. Now we'll go back to the road-house. It's long past time for luncheon."
Time wore on. Now that there was something definite to work on, the secret service began to take a more active part in the spy hunt.
"You have helped us greatly," said the Chief to Captain Hardy, one day. "My men were so rushed with work that they simply could not take the time to go hunting round for clues. But now that the wireless patrol has furnished those clues, we shall be able to follow them up. But we want you to continue at work just the same. You can still help us."
But the members of the wireless patrol, and especially Henry, found small satisfaction in the Chief's praise. They had not come to New York merely to furnish the secret service with clues. They had come to uncover the system by which spies were betraying the movements of our transports. At the Elk City reservoir they had succeeded where trained men had failed; and they meant to succeed here also. They felt that the Chief was patting them on the head, as it were, and telling them that they were good little boys. They meant to show him they were the equals of his own men, even if the Chief's words, instead of pleasing them, stimulated them to half angry activity.
"He needn't think that just because we're boys and come from the country we aren't any good," argued Roy. "That's the way everybody talks about boys. That's the way they talked about us at Elk City until we caught the dynamiters and showed them what we could do. We'll show Uncle Sam's men, too. I don't care if they are famous detectives. We'll get these fellows ourselves. We're not going to have the secret service step in now and take all the credit."
But it was one thing to talk so confidently and quite another to accomplish the end they were striving for. They had not yet discovered a single one of the hidden wireless stations, and the secret of the dollar was still a secret. As far as the members of the wireless patrol could see, it was likely to remain a secret. How they could secure one of the dollars without being detected, they did not know; and how they were to read the message, even if they did get the dollar, was more than they could see; for by this time they had dropped the idea that the messages were engraved on the coins. More and more those dollars appeared a great and insuperable obstacle.
"Couldn't we manage to see the spy when he marks those dollars?" asked Roy. "Is there any way that we could get into his house and hide, so as to watch him?"
"You mustn't think of trying," said Captain Hardy decisively. "But possibly you could find a new place to watch from that would enable you to see him better. These field-glasses of mine are very powerful, and if you can find the proper view-point, you can see him well, even from a distance."
Without a word Roy grabbed his hat and darted out of the house. A second later he was slipping through the thicket on the sloping hillside. Cautiously he crawled from one point to another. The only station that gave any promise of success was the pine grove originally selected. The tree from which they had been watching the spy's house was a giant pine that towered above every other tree in the grove. But the scouts had never dared to ascend beyond the protecting foliage of the other trees, lest they be detected. So they had been looking upward at an angle, as they watched the spy's house. Roy now saw that if he were to climb high up in the big pine, he would be on a level with the spy's windows, and could doubtless see clearly into the house. The difficulty would be to make the climb without being detected.
Roy made his way back to headquarters and reported on his observations. "I didn't go up," he said, "for fear he would see me."
"You were wise," replied Captain Hardy. "We must devise some plan by which you can get up the tree unnoticed."
"Camouflage!" said Willie suddenly. "Fix one of us up like a pine tree. Then he won't see us."
"Just the idea," said Lew laughing.
"We'll have to use the smallest boy in the bunch," said Captain Hardy, "and that's you, Willie. Come. We'll see what we can do with you. Go get me some samples of pine bark and needles."
Willie speedily got the desired objects. Captain Hardy examined them critically. "You ought to have a dark brown suit, painted with irregular stripes, like branches, and dabs of green, like foliage."
"Don't forget his face," cried Roy in glee. "That will have to be painted brown and green also."
A laugh went up. "I'm merely telling what ought to be done, Willie," said Captain Hardy reassuringly, "not what we shall do. We have to guard against observation by persons other than this spy. If the neighbors saw a boy going out of here garbed the way you want Willie fixed up, Roy, they would begin to ask questions. And we don't know what the spy's relations are with his neighbors. What we shall have to do is to dress Willie in clothes as nearly the color of the tree as possible. We can get shoes, stockings, and a suit of clothes to match the tree trunk. We can get a cap the shade of these pine-needles. That leaves hands and face. They, too, must be disguised. A pair of gloves of the proper shade will take care of the hands. But what about the face?"
"Nothing for it but to paint it," said Roy, his eyes dancing.
"I guess you're right," said Captain Hardy. Willie made a wry face. The captain saw him. "The trench raiders blacken both their hands and faces when they steal out into No Man's Land at night," he said. "But we won't use real paint, Willie. We'll get some theatrical paint that comes off easily. I'll get the necessary materials at once."
He noted down the sizes needed and went out. And it was well he acted so promptly. That very afternoon a message from the secret service informed them that more transports were sailing.
"Come with me and get on your pine tree outfit, Willie," suggested their leader. "You other boys go to your stations at once."
Henry's task henceforth was to trail the driver of the roadster. He hurried away to his waiting motor-cycle. Lew was at the wireless key again. Roy scurried out to the pine grove, and Willie followed his captain to be "camouflaged." A few moments later, dressed in his new brown clothes, and a chocolate brown in complexion, he slipped from the house and joined Roy.
Impatiently they waited for the first transport to appear. It was a long time coming. But finally Willie picked it out with his glasses, far up the Bay, as it nosed its way steadily through the rolling waves. Behind it was another transport. As the ships drew near, Willie mounted as far up in the tree as he dared, crouching behind the tops of the surrounding trees, and hugging his own tree trunk, motionless, awaiting his opportunity to climb to his ultimate post. His heart beat fast. His legs shook slightly with excitement. He was trembling all over, so eager was he to make the ascent. On came the boats. Long ago they had passed Robbin's Reef. Now they were well into the Narrows. Suddenly the spy appeared at his window, sweeping the channel with his glasses, his hands shutting off his vision on the sides, like blinders on a horse. Quickly Willie scurried up the tree, wrapping himself closely about the slender trunk, concealing as much of his body as he could, and snuggling behind the sparse clumps of foliage. Then he brought his glasses to bear, and sat silently studying the spy's house.
The interior of the dwelling was as he had guessed it to be. There was no partition wall in the forward part of the building, a single column upholding the ceiling, so that, above the low sash curtains, Willie could see entirely through the glassed-in room. This was more than comfortable. Willie saw a row of low book-shelves lining the north side of the great room. There were numerous fine pictures and plaster casts here and there. A piano stood in one corner, a talking-machine in another. The light within seemed to flicker, and Willie guessed that in the rear of the room, where he could not see it, a log was burning in an open fireplace; for the days were growing very chilly.
But before Willie could complete his observations, the spy turned from the window and walked toward a large, flat desk in the centre of the room. Willie shrank close against the tree and remained as motionless as a stone image. But the spy never once glanced out of the window. He sank into a chair before the desk, switched on an electric desk light, and began to write on a piece of paper. Evidently he was arranging his message. When this was done to his satisfaction, he reached into the desk and drew forth a dollar. Willie could see it plainly as the spy laid it on his desk blotter, under the lamp. Intently Willie strained forward. The spy leaned forward and fumbled about the bottom of his desk. His hands and arms were hidden and Willie could only conjecture what was happening. Then Willie gave a little gasp of surprise as the spy straightened up and laid on the blotter beside the dollar a curious little thing like nothing Willie had ever seen. Evidently it was of metal for it shone under the light. Willie screwed up his face as he strained his eyes to identify the object. It seemed to be a disc of exactly the same size as the dollar. Yet it was not solid, because Willie could see the blotter through it. To Willie the thing resembled nothing so much as a spider-web. What it was, Willie could not even guess.
Meantime the spy had pulled open a drawer, from which he took a slender instrument, which also Willie could not identify. But evidently it had a sharp point; for the spy, after placing the disc on the dollar, scratched the milled edge of the coin with the little instrument, then he began to make marks here and there through the little disc, on the surface of the dollar. From time to time he turned the coin, and occasionally he looked at the writing on his paper. He seemed quite expert, for he worked fast. He finished his task and leaned over behind his desk, evidently to put the curious disc in its secret repository.
Quick as a flash, Willie slid from his exposed perch and safely gained the concealing shelter of the lower tree tops before the spy straightened up again. Willie climbed on down the tree and joined Roy at the usual observation post.
"What did you see?" asked Roy eagerly.
When Willie had told him, Roy groaned. "Gee! That makes it all the harder. Now we've got to get one of those discs as well as a marked dollar before we can discover how they send their messages."
The grocer's boy came and went. Roy trailed him back to the store, but prudently kept out of sight. There was nothing to be gained by entering the store again. Meantime Willie scrambled up to the house and related to Lew and his captain what he had seen. And they agreed with Roy that the problem, instead of being easier, had become more difficult.
Henry, meantime, was waiting at his station with eagerness and quickened determination. Despite his leader's generous words, Henry felt in his heart that his last effort had been a failure. It was true that he had made it possible to learn the identity of the driver of the roadster, and that the secret service men had in the meanwhile been looking up the man's record; but Henry felt that he should also have discovered the location of the secret wireless. Now he made up his mind that nothing should balk him in the present attempt. That neither accident nor anything else should hinder him from accomplishing his purpose. He would be more skilful than he had ever been before. He would watch closer. He would follow his quarry, as silently as a shadow and as closely. He would do all that his leader expected of him—and more.
Thus resolving, steeling his mind to the greatest effort of his life, Henry stood at the little window in the garage, all atremble with eagerness. He thought he knew every inch of the spy's roadster, but when that car finally rolled past, Henry studied it as he had never studied anything before. Again he noted the tread of each tire and looked for cuts or other distinguishing marks in them. As good luck would have it, a turning wagon obstructed the roadster just as it reached the little garage, and the roadster came almost to a dead stop. Henry studied its running-gear, its radiator and bonnet, its dash-board and wind-shield. And when his eyes got so far, they went no further. The standards that held up the wind-shield were bulkier and thicker than any other such parts Henry could remember. The difference was not great, yet there was a difference; and like the accomplished scout he was, Henry noted that difference and questioned it. But, like Willie with the spider-web disc, he was completely puzzled. The enlarged standards might mean anything or nothing. The car rolled on and again Henry looked in vain at the number. Some part of it was always dust covered. But Henry observed that the hidden figures were not the same from day to day.
When the car returned from the grocer's, Henry jumped to his motor-cycle and made his way to the ferry by a route different from the roadster's. He knew he was taking a chance, but he also knew that an accomplice might be trailing the roadster to see if the latter were watched. Henry could follow the spy to the ferry once without arousing much suspicion; but if he were twice seen to do so, his usefulness might be ended. He knew when the ferry-boat would leave its slip and he made his way aboard just before the gate closed.
At once he had a feeling that he had acted wisely. The roadster was again in the forward part of the boat, but this time the driver did not sit placidly looking out over the Bay. He seemed nervous, and every little while turned sharp around and looked about him. Fortunately Henry had concealed his wheel behind a truck and was himself where the spy could not see him. When he noted the spy's restlessness, it flashed into his mind that perhaps the secret service men who had been investigating this spy had not been so careful as they should have been, and that the spy had taken alarm. It was a discouraging thought, for it made Henry's task vastly more difficult. Wisely, therefore, he went into the cabin and sat down. The spy could not see him, and if the latter should stroll about the boat, there was nothing to indicate to whom the motor-cycle belonged.
As the gate opened and the roadster rolled from the ferry-boat, Henry prudently remained well behind it. Up Broadway they went, as fast as the traffic would allow, their pace gradually quickening as they drew away from the congested lower end of the island. The spy drove straight up Broadway. He circled Union Square and continued north. He passed Madison Square and still held to Broadway. Past the shopping district, past Longacre Square, past Columbus Circle, the roadster continued, still on the city's main highway. And at a discreet distance Henry followed.
Now they reached the apartment-house district and slid past block after block of bulky living apartments. And so they continued past Columbia University and down the grade beyond. And here Henry's troubles began. The roadster turned to the left, and Henry knew the driver was making for the Fort Lee ferry.
How should he gain the boat unnoticed? How should he follow, undetected, along the Jersey roads? For after they had crossed the Hudson there would be an end to that concealing traffic that had so far hidden him. He must follow the roadster over lonely roads and yet remain unseen. It was a problem to disturb any one. And it worried Henry not a little. Fortunately dusk was at hand, though the curtaining darkness would not fall for some time.
When the boat reached the Jersey shore, Henry permitted the roadster to get a long start before he went ashore. The spy turned to the right and began to climb the long grade parallel to the river, that would lead him to the top of the Palisades. When the roadster was almost out of sight, Henry mounted his motor-cycle and followed. Even if his quarry should pass completely from view, Henry had no fear of losing him; for the roadster's tracks were plain in the dusty road.
The dusk deepened. As it grew darker, Henry came closer to his quarry, though he kept behind elevations and curves in the road so as still to remain invisible to the driver of the car ahead. Thus they rode for some miles. The country was as Henry had pictured it from his study of the maps. It was sparsely built up, woodlands were on every hand, and the surface of the land was rolling and rock-strewn. It was an excellent place in which to hide—and also an excellent place in which to dodge one's enemies. As Henry thought of this, he drew closer and closer to the car, though still seeking to remain out of sight. As the light failed, and it became difficult to distinguish the marks in the dust before him, Henry drew up so that he could see the roadster, but he discreetly rode close to the side of the highway, where the overhanging trees shadowed him. Even had the roadster's driver been looking straight in his direction, he might never have seen Henry. He was, as he had determined to be, a veritable shadow.
So they rolled northward. At last it grew dark. The driver of the roadster switched on his lights. Now Henry crept still closer. He was in the dark, his lamp unlighted, his motor running silently, and he had no further fear of discovery.
It was well that darkness had come. They had now reached a lonely region where there were few houses. Here, Henry judged, was an excellent place for a secret wireless. And he judged correctly, for hardly had the thought come into his mind before the roadster turned sharply to the left and disappeared. Henry darted up the road. He came at once to what he judged was a large field. Trees no longer bordered the highway on the left side. Dimly Henry saw objects here and there which he thought were boulders and clumps of bushes. He saw no light and stood for a second peering into the darkness, listening with bated breath. Straight ahead of him he heard the faint purring of a muffled motor. He knew that he was not many hundred feet behind it and that this time the car could not escape him. He thrust his motor-cycle into some near-by bushes, first whipping out his metal cane. Then he ran speedily but carefully after the car.
Evidently it was moving cautiously. Henry rapidly drew near to it. When he had come so close that he could see it distinctly, he dropped to a walk and began to look about, trying to see what was around him. Here in the field it was lighter than it had been on the highway under the shadowing trees. The field was, as Henry had guessed, a piece of wild land, grown up with thickets, with great boulders here and there. Directly ahead of him was a clump of bushes. Henry hastened to put them between himself and the car. It was well he did; for hardly had he gotten behind them before the car stopped and the driver got out. The car was not more than two hundred feet distant.
Henry dropped to the ground and lay still for a moment. Then he crept, like an Indian, toward the sheltering thicket. Through it he advanced until he was not more than fifty feet from the motor-car. He could see with fair distinctness, but was himself completely concealed. He lay like a log, watching intently.
The driver unfastened his top and slid it backward. As he did so, his overcoat caught on the open door and he gave an exclamation of impatience. When he had laid his top back, he lowered the upper half of his wind-shield. Then, standing on the running-board, he tugged at the top of his wind-shield standard. Up came a sliding inner tube. In a flash the entire mystery stood revealed to Henry. The wind-shield standard contained a collapsible mast, like the telescoping cane he held in his hand. Doubtless an aerial was now fastened to the mast. Somewhere within the car was a wireless outfit. Instead of having many secret stations, the Germans had this one portable station.
Up came a sliding inner tubeUp came a sliding inner tube
Up came a sliding inner tubeUp came a sliding inner tube
"How clever!" thought Henry. "And how well they deceived us."
The spy proceeded to run up his mast. It must have reached twenty feet into the air. And the aerial was dangling from it, too. Evidently the spy had fastened that on before raising the mast. Fifty feet distant stood a tree. The spy took something from the baggage container and walked over to the tree, where, Henry judged by the sound, he was fastening a hook. Then the spy carried over the other end of his aerial and fastened it to the hook. In the darkness Henry could see nothing of the details of this outfit, but he realized that the spy now had an aerial at least fifty feet long and well above the ground. For short distance communication it would answer perfectly.
The spy returned to his car and got into the seat beside the driver's. Henry wormed his way forward as far as he dared, hardly breathing, fascinated by what he beheld. For now he could see plainly. The spy had turned on a tiny light on his dashboard. Cautiously Henry rose to his feet, keeping behind a thick bush, and peered over the side of the car. The spy took a key from his pocket and unfastened a hidden lock. The entire cowl board turned down, revealing a compact but powerful wireless outfit. The aerial wire evidently was strung up within the collapsing mast.
From within the cowl the spy drew forth a curious metal disc, not unlike a spider-web, and like nothing Henry had ever seen. He did not know what it was. He hardly breathed as he stood watching. Then the spy took a dollar from his pocket, examined the milled edge until he found a scratch, fitted the curious disc over the dollar, and turning the coin in his hand, slowly began to make letters on a slip of paper on the inverted dash. When he had finished writing, he fastened the disc back in the cowl, dropped the dollar in his overcoat pocket, and began to send the message he had deciphered from the dollar.
Henry leaned forward. He had no need of his own receiving instrument to catch the letters. And he could not have used it if he had needed it. But it was not important that he should catch the message. The powerful sparks that were leaping across the spy's spark-gap told him that a battery of considerable force was being used, and he knew that Lew would catch that message away back on Staten Island. Lew had caught the preceding message from Long Island, and it had been sent from a distance fully as great as this. With distinctness the letters came to Henry's ears and he realized that the man before him was an expert operator. But the letters he heard made no sense. They would have to be deciphered before the message could be understood.
However, it was not the message that Henry was thinking of. It was the dollar in the man's overcoat. "How could he get it? How could he get it?" he asked himself over and over. A hundred wild ideas flashed through his head, but he could think of no way to secure the coin without betraying himself.
Even as he was considering the matter, the spy finished sending his message and snapped off his light. Tiny as the illumination had been, the man was apparently completely blinded by the sudden darkness. As he stepped from his seat, his overcoat again caught on the swinging door. With an impatient oath he tore the coat from him and flung it on the running-board. Then he felt for his tools and walked over to the tree to lower the far end of his aerial.
Henry's chance had come. With a bound he was beside the car. Crouching, he seized the huddled coat, ran his hands tremblingly over it, located the pocket, found the dollar, dropped the coat where he had gotten it, and slipped back to his cover.
He was not a second too soon. In his eagerness to get the coin he had been clumsy, and had fumbled excitedly for several seconds before he found it. Meantime, the spy, with practised skill, had taken down both wires and fastening, and was well on his way back to the car. But Henry gained his cover and was safe.
A sudden fear smote him lest he betray himself. His heart beat so loudly he was sure the spy would hear it. His breath came so excitedly he was certain he could be heard yards away. For some time he crouched motionless, hugging the ground, trying to hold his breath. But as second followed second and the spy made no outcry, Henry gained confidence. Suddenly a feeling of exultation came to him, so strong that he could hardly refrain from shouting. For the first time he thought of the real significance of what he had accomplished. He had unraveled the mystery of the wireless. He had the dollar. The secrets the wireless patrol had worked so hard to uncover were within his grasp. As the full meaning of it all came to him, he felt that he must cry out, that he must give voice to his feelings. He no longer dared trust himself to remain where he was, lest he betray himself. Clutching the dollar as he had never clung to anything in his life, he picked up his cane and slowly began to worm his way backward, on his belly, from the thicket. With the utmost caution, an inch at a time, he moved, lest he snap a stick or strike a stone with his foot. As soon as he was clear of the brush, he faced about, and crawled into the darkness.
The spy, meantime, was proceeding rapidly in reassembling his car. Henry heard the windshield go up and the top being fastened. He heard the baggage lid snap into place. Then he heard the spy swearing in a low voice. Henry stopped, still as a hunted rabbit.
"Donnerwetter!" he heard the man say. "I've lost that dollar." There was a pause. Then came the words, "I'm not going to hunt for it anyway. Somebody would see my light sure. And if anybody does find it, he'll never guess what it is."
Exultantly Henry rose to his feet, and crouching low, ran with soft, swift tread to his motorcycle. He had the dollar. The owner believed it was lost. Never was such luck. Trembling all over, he fastened his cane to the frame of his wheel, trundled his car to the road and ran with it in the direction he had come. He pushed it until his breath was coming in gasps. Then he turned into the woods and hid. He would take no chance of being seen by the spy or by any accomplice who might have followed him. Presently Henry heard the motor-car pull out into the road and go speeding back toward Manhattan. A quarter of an hour later Henry returned to the highway, switched on his light, and was soon bowling along on his way to his fellows and his chief, feeling that he had in his keeping the future safety of a nation.
In the house above the hawk's nest, four boys and a man sat far into the night, examining a marked dollar and trying to unravel the secret of the scratches. From hand to hand the dollar passed and was examined now this way, now that; but the little group could see no meaning in the apparently aimless marks on the silver coin. Had some of them not seen this dollar marked and its message deciphered and sent vibrating through the air, they would have refused to believe that the coin before them carried a message at all. It looked like any dollar that has accidentally become marked.
"To-morrow," said Captain Hardy, "we will turn the dollar over to the secret service, and doubtless their experts will solve the problem quick enough. But I certainly wish we could unravel this thing ourselves. Wouldn't it be an achievement for the wireless patrol!"
"It's going to be," declared Roy positively. "We're going to solve it. We've just got to. We'll show those secret service men that boys are some good after all."
But the word was easier than the deed. Puzzle their brains as they might, search the dollar as they would, they still found no key to the language it spoke.
"Tell me again what the message was," demanded Henry for the twentieth time, and Lew once more passed to Henry the slip of paper on which he had written the message, both in cipher and deciphered, the message he had picked from the air. It read as follows: TRPSLOWAOSEDONBADATSTITY.
T R P S L OW A O S E DO N R A D AT S T I T Y
Long Henry studied the piece of paper, softly reading the message to himself. "Two transports sailed to-day. How did that automobile driver get that message from this dollar?" he asked himself, and again he picked up the coin and turned it in his hand. "If only we had that disc," he sighed, "or a duplicate."
At the word "duplicate," Roy pricked up his ears. "Maybe we can make one," he said.
"Likely!" scoffed Lew.
"You never know till you try," rejoined Roy. Then he turned to Willie and demanded, "What was the disc like that you saw?"
"If I knew, I'd make one," said Willie.
"Well," said Roy in a tone of disgust, "you know whether it was a foot across or not, and whether it was round or square."
"It was round, of course," said Willie, "and the same size as the dollar. I told you that before."
"We can make a disc the size of a dollar, anyway, even if it doesn't get us anywhere," said Roy, putting the coin on a sheet of paper and outlining it with a pencil. Then with scissors he cut the disc out.
"You saw that disc, or one like it, Henry," continued Roy. "What did it look like to you?"
"Just like a spider-web, as Willie says," replied Henry.
"All right, we'll make a spider-web," said Roy.
He seized his pencil, made a dot in the centre of the disc, and from the dot drew straight lines that radiated in different directions. Then he drew a number of concentric circles about his dot.
"I don't see how that helps any," he said, examining his drawing. "Yet that's the kind of thing they used to mark that dollar."
From hand to hand the paper passed, and each boy compared it with the dollar. But none was any the wiser when he had finished. Their leader, meantime, sat with his head in his hands, studiously turning the matter over and over in his mind. For a long time he could make nothing of it.
After a while he looked up. "Let me see that paper," he said.
Roy handed him the little disc. Captain Hardy laid the disc beside the dollar on the table, and painstakingly examined again the marks on the coin. After a time he took a sheet of paper and across it in a row wrote down the letters of the alphabet. Then he picked up the message and made check marks below the letters in his alphabet as he found those letters in the message. When he had gone through the message, his paper looked like this: