"Who else could have taken it?"

"There's only one answer," said Carter slowly and impressively. "Some one went into that store between the time you copied the message and the time I met you at the drug-store. You told me no one but a couple of girls had entered. Was there any one else? Think—think!"

"There was no one," said Jane thoughtfully, "no one except the two girls together. I never thought of suspecting them."

"What did they look like? Could you identify them?"

"I did not notice them particularly," Jane confessed. "I was expecting Mr. Hoff's confederate to be a man."

"They're using a lot of women spies," asserted Carter. "Don't you remember what the girls looked like?"

"One of them," said Jane thoughtfully, "wore an odd-shaped hat, a sort of a tam with a red feather."

"Would you know the hat again if you saw it?"

"I think—I'm sure I would."

"Well, that's something. Watch for that hat, and if you ever see it again trail the girl till you find out where she lives. If you locate her telephone Mr. Fleck at once. And now, what has happened to you?"

"I've so much to tell, important, very important, I think."

She hesitated, wondering how much Carter was in the chief's confidence. Did he know the import of the cipher message she had discovered? Ought she to talk freely to him?

"Do you know what those numbers meant?" she asked.

"Yes," he replied, "about the eight transports sailing. The Chief told me about it."

"Well," she said, with a sigh of relief, "I have become acquainted with young Mr. Hoff already. I've just had luncheon with him."

"That's fine," he cried enthusiastically. "A lucky day it was I ran across you."

"When you 'phoned me he was there in our apartment, he and a navy lieutenant, Mr. Kramer."

Attentively he listened as she told of the ruse by which she had inveigled them into coming to luncheon, reminding him that it was the same naval officer that he himself had seen in close conversation with Hoff at the Ritz the day before. He nodded his head in a satisfied way.

"They are together too much to be up to any good," he commented. "Tell me the rest. What made you so rattled when I 'phoned you?"

He listened intently as she told of finding young Hoff standing right behind her as she had inadvertently mentioned aloud "the fifth book."

"Do you suppose," she questioned anxiously, "that he overheard me and understood what we were talking about? He left right away after that. I do hope I didn't betray the fact that they are being watched."

"We can't tell yet," said Carter. "The precautions they take and the roundabout methods they have of communicating with each other show that all Germany's spies constantly act as if they knew they were under surveillance. In fact, I suppose every German in this country, whether he is a spy or not, can't help but notice that his neighbors are watching him—and well they might."

"I don't see why," cried Jane, "Mr. Fleck did not have old Mr. Hoff locked up right away. He could not do any more damage then, or be sending any more messages about our transports."

"That wouldn't have done the least bit of good," said Carter decisively. "Watching our transports sail and spreading the news is only one of many of their activities. Somewhere in this country there is a master-council of German plotters, directing the secret movements of many hundreds, perhaps many thousands of spies and secret agents. They have their work well mapped out. They have men fomenting strikes in the government shipyards and stirring up all kinds of labor troubles. Others are busy making bombs and contriving diabolical methods of crippling the machinery in munition plants. A flourishing trade in false passports is being carried on, enabling their spies to travel back and forth across the Atlantic in the guise of American business men, ambulance drivers, Red Cross workers and what not. Still others of their agents are detailed to arrange for the shipping of the supplies Germany needs to neutral countries. By watching shipping closely they gather information, too, that is of value to the U-boat commanders. Every time there is any sort of activity against the draft, or peace meetings, or Irish agitation, we find traces of German handiwork. We have dismantled and sealed up every wireless plant we could find in America except those under direct government control, yet we are positive that every day wireless messages go from this country somewhere—perhaps to Mexico or South America, and from there are relayed to Germany, probably by way of Spain. Think of the enormous amount of money required to finance these operations and keep all these spies under pay. While we try to thwart their plans as we find them, all our efforts are constantly directed toward discovering who controls and finances their damnable system. We seldom if ever arrest any of the spies we track down, but keep watching, watching, watching, hoping that sooner or later the master-spy will be betrayed into our hands."

"You don't think then," said Jane disappointedly, "that old Mr. Hoff is one of the important spies."

"We can't tell yet. He may be just one of the cogs—perhaps what they call a control-agent. We don't know yet. Germany has been building up her spy system forty years, and it is ingenious beyond imagination. Her codes are the most difficult in the world. It took the French three years and a half to decipher a code despatch from Von Bethmann Hollweg to Baron von Schoen. By the time they had it deciphered in Paris the Germans had discovered what they were doing and had changed the code. It is seldom any one of the German spies knows much about the work that other spies are doing. The rank and file merely get orders to go and do such a thing, or find out about such a thing. Often they are not told what they are doing it for. They obey their orders implicitly in detail and make their reports, get new orders and go on to do something else. Only their master spy-council here knows what the summary of their efforts amounts to. Arresting old Hoff, or a dozen more like him, would not cripple them much. Other men would be assigned in their places, and the nefarious work would go on."

"I don't know," insisted Jane thoughtfully. "I believe that old Mr. Hoff is a far bigger spoke in the wheel than you think. I watched his face as I followed him this morning. He is a man of great intelligence, and I should judge a man of education."

"They'd hardly be using a man of that sort to carry messages," objected Carter. "Maybe you're right. We have not watched him long enough to find out. We've got nothing yet on the young fellow. Maybe he's the real boss of the outfit. At any rate he is the one the Chief is anxious to have you keep tabs on. Are you to see him again?"

"Oh, yes," the girl answered quickly, a touch of color coming to her face, "I think so. I asked him to come to see me. I think—in fact I'm sure—he will. Do you want me to watch the bookshop to see if they leave any more messages there?"

"No," said Carter. "I've got one of my men assigned to that. You keep after the young fellow. Say, does your father keep an automobile?"

"Yes, but it's been put up for the winter. We're going to bring it out as soon as Dad can find a chauffeur. Our man—the one we had last year—has been drafted, and good chauffeurs are scarce now. Why did you ask?"

"I'll find you a chauffeur," said Carter decisively.

"You mean"—Jane hesitated—"a detective?"

Carter grinned.

"An agent like you and me. K-27 is an expert chauffeur and mechanic with fine references. His last job was with the British High Commission, and they gave him good testimonials."

"What do you want him to do?"

"Driving the Strong car makes a good excuse for him to be around without exciting suspicion. He might even come up-stairs once in a while to get orders or do little repair jobs around the apartment. Some day, supposing the people next door were all out, he might even succeed in planting a dictograph so that you could sit there in your room and hear all that was going on and what the Hoffs talked about. That would help a lot. If ever he was caught prowling about the hall, the fact that he was your chauffeur would provide him with an alibi. Do you think you can fix it up with your father?"

"I'm sure of it. When can he come?"

"The sooner the better—to-night—to-morrow."

"I'll tell Dad at dinner to-night that I've learned of a good chauffeur and have asked him to come in at eight this evening."

"Fine," said Carter. "He'll be there. And don't forget to report once a day to the Chief."

"I won't."

"And if anything unexpected turns up," said Carter, "and you need help, take a good look at that nurse that is passing."

Jane turned curiously to inspect a buxom girl in a drab nurse's costume who was wheeling a baby carriage along the sidewalk near-by. Seeing herself observed the girl stopped, and at a sign from Carter wheeled her charge up to where they were standing.

"K-22," said Carter, "I want to introduce you to K-19."

Gravely the two girls, nodding, inspected each other.

"She always wears a blue bow at her neck," Carter added, "so you can recognize her by that."

The girl smilingly nodded again and wheeled the carriage on up the Drive.

"Who is she?" Jane asked eagerly, turning to Carter.

"Just K-22," said the agent, "and all she knows about you is that you are K-19. That's the way we work in the service mostly. The less one operative knows about another the better, for what you don't know you can't talk about."

"Doesn't she even know my name?" persisted Jane.

"She may have found it out for herself while she has been watching the Hoffs, but we didn't tell her. Nobody in the service knows who you are except the Chief and myself—and of course K-27 will have to know if he takes the chauffeur's job."

"What is his name?"

"I don't know yet," said Carter gravely. "I haven't seen his references, so I don't know what name they are made out in. You can find out what to call him when he reports to-night. You'll see that he gets the job?"

"Indeed I will," answered Jane, experiencing a sense of relief at the prospect of having some one at hand in the household with whom she could discuss her activities.

And as she had anticipated she had little difficulty in interesting her father in the subject of a new chauffeur. Mr. Strong for several days had been trying to find one without success.

"You say this man's last place was with the British High Commission."

"Some one of the girls was telling me," she prevaricated. "I asked her to tell him to come here to-night at eight. He ought to be here any minute."

Presently the candidate for the place was announced.

"Mr. Thomas Dean to see about a chauffeur's position," the maid said as she brought him in, and while her father questioned him, Jane studied him carefully.

He could not be more than thirty, she decided, and the voice in which he answered her father's questions was surely a cultivated one. It would not have surprised her in the least to have learned that he was a college man. Even in his neat chauffeur's uniform he seemed every inch a gentleman. He had been driving a car for twelve years, he explained. No, he did not drink and had never been arrested for speeding.

"Are you a married man?"

Jane listened curiously for his answer to this question of her father's. Surely it would be far more interesting if he wasn't. Of course, he was a chauffeur and a detective, but somehow she could not help feeling, perhaps because of his easy manner, that more than likely most of the cars he had driven were cars that he himself had owned. K-27 she decided was going to be quite a satisfactory partner to work with.

"There's just one thing," said her father. "You say you are not married. I can't understand why it is that you are not in the army."

"I am not eligible," said Thomas Dean calmly, though Jane thought she could detect a twinkle in his eye. "One of my legs has been broken in three places."

"But there are things a young fellow can do for his country besides marching," insisted Mr. Strong. "The government needs mechanics, too."

"I know," said Thomas Dean, almost humbly, "but I have a mother, and my father is dead."

Jane smiled a little to herself at his answer. She noted how carefully he had avoided saying anything about having a mother to support. It would not have surprised her in the least to have learned that he was a millionaire, yet her father, ordinarily shrewd in judging men, apparently was satisfied.

"Supporting a mother, I suppose, comes first," he said. "Well, Dean, when can you come?"

"To-morrow morning if you like," the new chauffeur answered, nodding gravely to Jane as he withdrew.

Mr. Strong, as soon as they were alone, spoke enthusiastically about the young man, complimenting Jane on having discovered him, and as he did so a revulsion of feeling swept over her. For the first time she realized into what duplicity her work for the government was leading her. She had pledged her word to Chief Fleck that she would keep her activities an absolute secret even from her parents. Already she was deceiving them, bringing into the household an employee who really was a detective, a spy. She was tempted to tell her father, at least, what she was doing. He, she knew, was filled with a high spirit of patriotism. While he might not wholly approve of what she herself was doing she might be able to convince him of the necessity of it. If she could only tell him, her conscience would not trouble her, but there was her promise—her sacred promise; she couldn't break that.

While with troubled mind she debated with herself between her duty to her parents and her duty to her country, one of the maids came in with a box of flowers for her.

Eagerly she cut the string and opened the box. Chief Fleck especially wanted her to cultivate young Hoff's acquaintance. If her suspicion as to the sender were correct, she could feel that she had made an auspicious beginning.

In a tremor of excitement she snatched off the lid of the box and tore out the accompanying card from its envelope.

"Mr. Frederic Johann Hoff," it read, "in appreciation of a most profitable afternoon."

Wondering at the peculiar sentiment of the card she tore off the enclosing tissue paper from the flowers. Orchids, wonderful, delicately tinted orchids, nestled in a sheaf of feathery green fern—five of them.

"Five orchids—the fifth book—a profitable afternoon."

Jane felt sure now she had betrayed the government's watchers to at least one of the watched.



CHAPTER VII

THE WOMAN ON THE ROOF

It is amazing how much information on any given subject any one—even a wholly inexperienced person like Jane Strong—can acquire within a few days when one's mind is set resolutely to the task. It is much more amazing how much one can learn when aided and abetted by an experienced chauffeur, or more properly speaking a mysterious and cultured secret service operative, masquerading as an automobile driver.

Who Thomas Dean was, why he was in the secret service, and what his real name was, were questions that kept perpetually puzzling Jane. In the presence of her father and mother, so skilful an actor was he that it was hard to believe him anything but what he appeared to be, a respectful, intelligent and prompt young man who knew the traffic regulations and the anatomy of automobiles. When he and Jane were by themselves he invariably threw off his mask to some extent. He became the director instead of the directed, though never letting anything of the personal relation creep in. That he was college-bred, Jane felt certain. He spoke both German and French much better than she did. He occasionally used words that no ordinary chauffeur would be likely to know the meaning of. Sharing the secret of such a mission as theirs, they quickly found themselves on a friendly basis, yet the girl hesitated whenever her curiosity prompted her to try to find out anything that would reveal his identity. There was always present the feeling that any exhibition of undue curiosity on her part would be a disappointment to her employer. The chief disapproved of curiosity except on one subject—what the Germans were doing.

Many things Jane and her aide learned about the Hoffs in the days following Thomas Dean's coming, reporting them all as directed. Of how much or of how little value her discoveries were Jane had no means of knowing. Chief Fleck seemed satisfied but was always urging her to acquire more information and more details, always details. Dean, too, had seconded the warning about observing even what seemed to be insignificant trifles.

"Most of the Germans," he said to her, "you will find are very methodical. They like to do things according to schedule. For instance, I learned yesterday that old Hoff and his nephew frequently go off on all-day automobile trips. They always go on Wednesday."

"Are they going to-morrow?"

"The presumption is that they will. They have done so every Wednesday for six weeks."

"Can't we follow them in our car?" cried the girl, "and see what they are up to?"

Dean shook his head.

"The Chief is looking out for that. There is more important work for us to do right here. I want to try to install a dictograph in their apartment."

"How exciting."

"You must find some excuse for me to come up into your apartment and see to it that none of your people are about."

"That will be easy. Mother and Aunt will be out all day, and it is cook's afternoon off. I can easily send the maids out."

"But that's not all. There is the Hoffs' servant to be disposed of."

"I don't see how I can manage that," said Jane. She could think of no possible way of overcoming that difficulty.

"She's an old German woman—Lena Kraus," continued Dean. "I've found out that she always washes on Wednesdays. When she goes up on the roof in the afternoon to get the clothes will be our time. It will be your job to see that she stays there until I am through. It will not take me more than half an hour."

"But what will I do if she starts to come down? How will I stop her?"

"You'll have to use your wits. Keep her talking as long as you can. When she starts down come with her. Press the elevator button four times. I'll leave the door of the Hoff apartment open and very likely will hear it in time to get away."

"But how'll you get their door open?"

Dean smilingly drew forth a key.

"I borrowed the superintendent's bunch last night, pretending I had lost the key to my locker in the basement. I knew he had a master-key that unlocks all the apartment doors, and there was no trouble in picking it out. I had some wax in my hand and made an impression of it right under his nose."

"How clever," cried Jane, "but suppose the Hoffs do not go off to-morrow. What will we do then?"

"You are taking tea with young Hoff this afternoon, aren't you?"

"Yes," said Jane, "that is, he asked me to. I am to meet him at the Biltmore at five."

"When you're with him propose doing something together to-morrow afternoon. See what he says."

"That's an excellent idea. I'll ask him to go to the matinee with me."

"That will do splendidly. Has he been with that navy officer lately?"

"Not since Sunday, to my knowledge. I wonder if old Mr. Hoff has left any more cipher messages at the bookshop?"

"No," said Dean, "he hasn't. The place has been constantly watched, but he hasn't been near it since that first day."

"I'm afraid," sighed Jane despondently, "I betrayed the fact that we were watching them to the nephew. He overheard me talking to Carter about the 'fifth book,' and of course he knew what it meant. I'm certain the old man is still reporting about our transports. Every day I can hear some one telephoning to him. He waits for the message, and then he goes out."

"He certainly is expert in eluding shadowers," admitted Dean. "Every day he has been followed, but always he manages to give the operatives the slip. He must know he is being watched."

"I'm anxious to know what the nephew will say to me to-day," said Jane. "I know he knows what I am doing. He looks at me in such an amusedly superior way every time he sees me."

"Be careful about trying to pump him," cautioned Dean. "He strikes me as by far the more intelligent of the two. It would not surprise me in the least if he were not old Hoff's nephew at all, but really his superior, sent over especially by Wilhelmstrasse to take charge of the plotters. He doesn't in the least resemble old Hoff."

"No indeed, he doesn't," admitted Jane. "He certainly is clever, too. We haven't learned a single thing that incriminates him, have we?"

"Nothing definite, yet everything taken together looks damaging enough. Here is a young German of military age and appearance, who arrived from Sweden just before we went into the war. He has plenty of money and spends his time idling about New York, in frequent communication with at least one navy officer. He selects a home overlooking the river from which our soldiers are departing for France. You yourself saw him pursuing K-19—the other K-19—who a few hours afterward was found murdered."

"Things don't look right," Jane agreed, yet a few hours later as she sat opposite the young man at tea, she found herself doubting. It seemed incredible, impossible, that Frederic Hoff could be a murderer. Her instinctive sense of justice forced her to admit that it was hard for her to believe him even a spy. He seemed so cultured, so clean, so straightforward, so nice. If she had not seen that unforgettable look of hate on his face that night as she watched him from the window she could not, she would not have believed evil of him.

The tremor of nervous excitement in which she met him quickly passed, and she found herself once more chatting intimately with him and enjoying it. He talked well on practically all subjects, showing reserve only when she tried to draw him out about himself. Her previous experiences with the opposite sex had taught her that most men's favorite topic of conversation is themselves, but Mr. Hoff appeared to be the exception. Adroitly he baffled all her efforts to get him to discuss his family, his achievements, or his past, even when she sought to encourage intimacy by telling about her brother who was abroad in Pershing's army.

"You must let me be your big brother while he is away," her escort had suggested gallantly.

"All right, brother," she had challenged him. "I'll take you on at once. I have seats for a matinee to-morrow. I'd much rather go with a brother than with one of the girls."

"I would be delighted," he answered unsuspectingly, "but unfortunately I have an engagement that takes me out of town."

"We'll go next week, then—Wednesday."

"A week is too long to wait. Let me take you to a matinee on Saturday."

Jane hesitated. At times her conscience troubled her not a little. While satisfied that the importance of her trust wholly justified her actions, she disliked any deception of her family.

"Wouldn't it be better," she parried, "if you came to call on me some evening first? You've only just met my mother, and I would like you to know Dad, too."

"May I?" he cried with manifest pleasure. "How about to-morrow evening?"

"That's Wednesday," she answered slowly. That was the day she and Dean were planning to put in a dictograph. She wondered at herself calmly carrying on this casual conversation with the man she was planning to betray. Coloring a little from the very shame of it, she continued, "How about making it Thursday evening?"

"Delighted," cried Hoff, "and about Saturday's matinee—what haven't you seen?"

Glad for the respite of at least twenty-four hours, Jane, as they talked, watched his face, his expression, his eyes. Regardless of the things she believed about him, he impressed her as honest and sincere. Certainly there was no mistaking the fact that his liking for her and his delight in her society were wholly genuine. Her heart warned her that it was his intention to press their new-formed acquaintance into close intimacy. Was he, she wondered, like herself, pretending friendship merely to unmask secrets for his government? No, she could not, she would not believe it. She felt sure that his admiration was unfeigned. Something told her that quickly his ardor and determination might lead her into embarrassing circumstances. He might even ask her to marry him. For a moment she was overcome with timidity and tempted to stop short on her new career, but there came to her the thought of the brave Americans in the trenches, of the soldiers at sea, of the brutal, lurking U-boats, and sternly she put aside all personal considerations.

"You spoke of going out of town," she said when the subject of the matinee had been disposed of. "Don't you find train travel rather disagreeable these days?"

"Fortunately I'm motoring."

"That will be nice, if you don't have to travel too far."

"It is quite a distance for one day, but I am used to it. I make the trip often."

Feeling that at least she had learned something, Jane rose to go. She knew that both the Hoffs would be out of the way to-morrow. The inference from his last remark was that they were going to the same place they had gone on previous Wednesdays. That was something to report to Mr. Fleck.

"My car is outside," she said as they rose. "Can't I take you home?"

"Sorry," said her host, "but I am dining here to-night. Lieutenant Kramer is to join me."

"Remember me to him," she said as he escorted her to the automobile, driven by Dean.

A block away from the hotel she tapped on the glass, and as Dean brought the car to a stop she climbed into the seat beside him. Only a week ago she would have criticized any girl who rode beside the chauffeur. In fact she had spoken disapprovingly of a girl in her own set who made a habit of doing it, but now she never gave it a thought. Many things in her life seemed to have assumed new aspects and values since she had entered on a career of useful activity. In her was rapidly developing something of her father's ability and directness. As she wanted to talk confidentially with Dean, she went the easiest way about it, entirely regardless of appearances.

"Apparently you carried it off well," he commented.

"I hope so," she answered, coloring a little. "They're making their usual Wednesday motor trip."

"He did not tell you their destination?"

"No, but Lieutenant Kramer is dining with him to-night at the Biltmore."

"Fine. Those things the Chief can take care of. That leaves the way clear for us to-morrow afternoon."

"What excuse will I make for having you come up to the apartment?"

"You want me to change some pictures. That will account for the wire if I'm caught."

"I hope no one sees you."

"Nobody'll see me but the elevator man, and he'll think nothing of it."

Apparently, too, Dean was right, for the next afternoon he entered the Strong apartment carrying a suitcase in which was concealed his apparatus and the necessary wire.

"Hurry," cried Jane, who was waiting for him. "The Hoffs' maid has just gone up on the roof."

"We can safely give her at least a few minutes," said Dean setting to work to make a hole through the wall into the apartment adjoining. Just as he had finished making it and had pushed one end of the wire through, the telephone bell rang, and Jane in dismay sprang to answer it.

"Disguise your voice," warned Dean. "If it is a caller say there is no one home."

"It was Lieutenant Kramer calling," said Jane as she returned.

"Did he recognize your voice?"

"I don't think so."

"What did he say?"

"He said to tell Miss Strong that he had called."

"Then he didn't suspect you."

"Isn't there danger, though, that he may come up to the Hoff apartment?"

Dean sprang to the window and looked out at the street below.

"No, there he goes up the street. He evidently did not try to see if the Hoffs were at home. That's funny."

"Why funny?"

"It means of course that he, too, knows about those Wednesday trips the Hoffs make."

Cautiously he opened the door into the public hall. There was no one about. Catlike in swiftness and silence he moved to the Hoff door and inserted his new-made key. It worked perfectly.

"Now," he whispered to Jane, "to the roof—quick. I must not be taken by surprise. Give me at least ten minutes more—fifteen if you can."

Quickly he passed inside, closing the door behind him all but a barely noticeable crack, as Jane rang for the elevator and bade the operator take her to the roof. As she emerged there and stood waiting for the elevator to descend again, an ornamental lattice screened her from the rest of the roof. Cautiously and curiously she peered between the slats, trying to see what the Hoff servant was doing at the moment. She decided that she would not reveal her presence until the woman made ready to go down-stairs.

As from behind her screen she scanned the roof she espied old Lena over on the side next the river bending over a half-filled basket of clothes, apparently putting into the basket some of the freshly dried laundry from the lines extending all over the roof. As Jane watched her the old woman straightened herself up and cast a cautious glance about. Apparently satisfied that she was alone she whipped out something from a pocket in her apron and turned in the direction of the river.

Jane gasped in amazement, a thrill of excitement sweeping over her at this new discovery. It was plain that the old servant was studying the transports in the river below through a pair of powerful field glasses. Curiously Jane observed her, wondering what she was trying to ascertain, wondering if through the glasses she was able to identify the battleships and other boats. Old Lena's next move was still more puzzling. Hastily dropping her glasses into the basket she began to hang again on the line some of the clothes. They were handkerchiefs, Jane noted interestedly, one large red one, and the rest white, some large, some small, a whole long row of nothing but handkerchiefs.

All at once it came to Jane what it must mean. The arrangement of the handkerchiefs must be some sort of a code. She studied the way they were placed, committing the order to memory. "Red—two large—one small—one large—one small." Of course it was a code, a signal to some one aboard one of the ships.

The line of handkerchiefs completed old Lena once more took up her glasses, first looking around as before to see if any one were on the roof. How Jane wished that she, too, could see the ships from where she stood. Was some traitor in the navy wigwagging to the old woman? She was tempted to spring forward and seize her and stop this dastardly signalling, but she remembered her duty. She was there to see that Dean was not surprised by old Lena's return. So long as the woman kept signalling he was safe.

Once more the laundress dropped her glasses and began frantically rearranging the handkerchiefs. Again Jane noted their order—red—two small—one large—three small—two large. Again the laundress resorted to the glasses, and at last, apparently satisfied, began taking down the rest of the laundry and making ready to leave the roof. Trying to act as if she had just arrived, Jane stepped boldly forward.

"I wonder," she said approaching the woman, "if you can tell me where I can find a good laundress."

"Nicht versteh" said old Lena, eyeing her suspiciously and hostilely, and at the same time attempting to pass her with the basket of clothes.

Deliberately blocking the way, Jane repeated her question, this time in German, feeling thankful that her language studies at school were not wholly forgotten and that they had included such practical phrases as those required to hire and discharge maids and complain about the quality of their work.

"I know no one," the old woman answered her, this time in English.

Jane breathed fast with excitement. The laundress' slip of the tongue, after denying that she understood, was evidence in itself of her deliberate duplicity. Realizing her mistake, the old woman now sullenly refused to answer any questions, merely shaking her head and trying to dodge past and escape.

To prolong the questioning, Jane felt, would be only to arouse suspicion, and reluctantly she allowed old Lena to precede her to the elevator, anticipating her, however, in ringing the bell, pressing the button four times as Dean had directed. As they descended together she was almost in a panic. How long had she kept the laundress on the roof? She really had no idea. She had been so absorbed in her new discovery she had given no thought to the time. For all she knew she might have been there only five minutes. Had Dean had time to finish his work?

Almost frenzied with anxiety, wondering if it were too soon, she moved forward in the car so as to obstruct old Lena's view through the door as it opened. One glance showed her the Hoff door now tightly closed, and she thought she heard the door of her own apartment just closing. Suddenly she remembered that she had gone up on the roof without a key. It would be a pretty pass if Dean were still in the Hoff apartment and she couldn't get into her own.

All in a tremble she pressed the button of her own door, waiting, however, to see that the laundress was out of the hall. It was Dean who opened the door, and she all but fainted in his arms as she saw that he was back in safety.

"It's done," he cried gleefully, as he caught her and drew her within, closing the door carefully behind her. "I just finished my work as you came down."

Great drops of perspiration still stood on his forehead and he was breathing rapidly.

"Why, what's the matter?" he cried, noticing for the first time Jane's perturbation. "Was it too much for you? What happened?"

"Put this down quick, quick," gasped Jane, "Red—two large—one small—one large—one small—and then—red—two small—one large—three small—two large."

Wonderingly he complied, jotting down what she told him in his notebook, and turning to ask her what it meant, discovered that she had fainted.



CHAPTER VIII

THE LISTENING EAR

"I don't know what is the matter with Jane," sighed Mrs. Strong a few days after the employment of the new chauffeur.

"She's not ill, is she?" responded her husband. "I never saw her looking more fit."

"She looks all right," said her mother. "It is the peculiar way she is acting that bothers me. She spends hours and hours moping in her room, and then there are times when she takes notions of going out and is positively insistent that she must have the car."

"Maybe she's in love," suggested Mr. Strong, resorting to the common masculine suspicion.

"With whom?" retorted his wife indignantly. "I don't believe there is an eligible man under forty in all New York. None of the men are thinking about marriage these days. They all want to go to France, even the married ones. I believe you'd go yourself if you were a few years younger."

"I certainly would," announced her husband enthusiastically.

"Jane tells me she is writing a novel," Mrs. Strong continued, "and that's why she stays in her room so much. I hope she won't turn out to be literary."

"Don't worry," advised Mr. Strong. "With all the men off to war you'll find young women doing all kinds of funny things to work off their energy. If a girl can't be husband-hunting, she's got to be doing something to keep busy. There are worse things than trying to write novels. Jane is all right. Let her alone."

So, even though her mother's suspicions had been aroused, the girl in the next few days managed to spend many hours with her ears glued to the receiver of the dictograph without being discovered. In the Hoffs' apartment Dean had succeeded in locating it over the dining-room table, concealed in the chandelier, and in Jane's room the other end rested in the back of a dresser drawer that she always carefully locked when absent.

The novelty of listening for bits of her neighbors' conversation quickly wore off. To sit almost motionless for hours listening, listening intently for every sound, hearing occasional words spoken either in too low tones or too far distant to make them understandable, to record bits of conversation that sounded harmless, yet might have some sinister meaning, became a most laborious task. Yet persistently Jane stuck at it. The greater knowledge she gained of the plottings of the German agents, the more important and vital she realized it was for every clue to be diligently followed in the hope that the trail might at last reach the master-spy, whose manifold activities were menacing America.

In general she was disappointed with the results of her listening. To be sure they had furnished indisputable evidence of something they already had ascertained—that old Hoff, despite being a naturalized American, still was a devoted adherent of the ruler of Germany. Nightly as he and his nephew sat down to dinner she could hear his gruff, unpleasant voice ceremoniously proposing always the same toast:

"Der Kaiser!"

Even when the younger Hoff was dining out, as he sometimes did, Jane could hear the old man giving the toast, presumably with only the old servant for an auditor. That the woman, too, was a spy, as well as servant, Jane had known since the day on the roof, but so far neither she nor Dean had been able to make anything out of her handkerchief code, though both were sure the messages related to the sailings of transports.

Only once had she heard anything that she deemed really important. One evening, as uncle and nephew dined, there had been an acrimonious dispute.

"Have you it yet?" the uncle had asked in German.

"Not yet," Frederic had answered.

His seemingly simple reply for some reason appeared to have stirred the elder man's wrath. He broke into a volley of curses and epithets, reproaching his nephew for his delay. In the rapid medley of oaths and expostulations Jane could distinguish only occasional words—"afraid"—"haste"—"all-highest importance"—"American swine." The younger Hoff had appeared to exercise marvelous self-control.

"There is yet time," he answered calmly.

"Donnerwetter," the old man had exclaimed. "There is yet time, you say—and Emil the wonder-worker almost ready has. It must be done at once."

The outburst over, old Hoff had subsided into inarticulate mutterings, evidently busy with his food, leaving Jane to wonder futilely who Emil might be, what he meant by the "wonder-worker," and what particular task had been assigned to the nephew that must be performed immediately. She had hastened to report this conversation in detail to Chief Fleck, but if he understood what it was about he had taken neither Jane nor Thomas Dean into his confidence.

Other things, too, Jane had learned and reported, which she knew the chief appreciated even though he was sparing in his thanks and compliments. She had learned through her almost constant listening that Lieutenant Kramer was a regular visitor, coming to the Hoff apartment or seeing Frederic Hoff somewhere every other day. Unfortunately he was always conducted into one of the inner rooms, so that no more of the conversation than the ordinary greetings and farewells ever reached Jane's ears. The mere fact of his coming so regularly to the Hoffs convicted him of treachery, in Jane's mind. What proper business could an American naval officer have in the home of two German agents? The excuse that Frederic Hoff was a delightful and entertaining friend was entirely too flimsy and unsatisfactory.

Nothing that she had overheard—and within her heart she felt glad that it was so—in any way as yet incriminated young Hoff. When she dared to think about it, she found herself almost believing, certainly at least wishing, that the nephew was not involved in his uncle's activities. Most of his time, in fact, was spent out of the apartment. He frequently went out early in the morning, not returning until the early hours of the next morning. The old man, on the contrary, always stayed at home until eleven o'clock. At that hour his telephone would ring. The telephone was located near the dining room, so Jane could easily hear his conversations. Invariably some brief message was given to him, a name, which he repeated aloud as if for verification.

As Jane overheard them she had set them down:

Thursday—"Jones." Friday—"Simpson." Saturday—"Marks." Sunday—"Heilwitz." Monday—"Lilienthal." Tuesday—"Wheeler."

As she sat by the hour listening Jane kept pondering over these names. What could they mean? Were they, too, a code of some sort? Always, as soon as this word had come to him, old Hoff went out. Could they be, she wondered, passwords by which he gained access somewhere to government buildings or places where munitions were being made or shipped?

Meanwhile her acquaintance with Frederic Hoff had been progressing rapidly. As she had suggested he had called on her and had been presented to her father, and on the next Saturday they had gone to a matinee together. She had been eager to see what her father thought of him, for Mr. Strong, she knew, was regarded as a shrewd judge of men.

"What does that young Hoff do who was here last night?" her father had asked at the breakfast table.

"He's in the importing business with his uncle, I think," she had answered.

"Where'd you meet him?"

"He lives in the apartment next door. Lieutenant Kramer introduced him."

"He's German, isn't he?"

"Oh, no," said Jane, almost unconsciously rallying to defend him, "he was born in this country."

"Well, it's a German name."

"Don't you like him?"

"He talks well," her father said, "and seems to be well-bred."

It was with reluctance, too, that Jane admitted to herself that the better acquainted she became with Frederic Hoff the more fascinating she found his society. She was always expecting that by some word or action he would reveal to her his true character. At the matinee she had waited anxiously to see what he would do when the orchestra played the national anthem. To her amazement he was on his feet almost among the first and remained standing in an attitude of the utmost respect until the last bar was completed. If he were only pretending the role of a good American, he certainly was a wonderful actor. As her admiration for him increased and her interest in him grew she found that almost her only antidote was to try to keep thinking of his face as she had seen it the night that K-19—the other K-19—had been so mysteriously murdered. She kept wondering if Chief Fleck had made any further discoveries about the murder and resolved to ask him about it at the first opportunity. She therefore was delighted when on Tuesday, as she made her regular report by telephone, he asked if she could come to his office that afternoon with Dean to discuss some matters of importance. They found Carter already with the chief when they arrived.

"Thanks to your work, Miss Strong, and to Dean's dictograph," said the chief, "we have made considerable progress. We have learned a lot more about the cipher messages."

"You have learned it through me," cried Jane in amazement.

"Yes," said the chief, smiling, "from that list of names you reported."

"What were they, a cipher, a code?" questioned the girl breathlessly.

"No, nothing like that. They are merely the names of various innocent and unsuspecting booksellers in various parts of the city."

"How did you discover that?"

"In the simplest and easiest way possible. I listed all the names you reported and studied them carefully, trying to find their common denominator. They were not in the same neighborhood, so it was not locality. They were not all German, so it was not racial. I looked them up in the telephone directory, checking up the numbers of the telephones of the Jones, the Simpsons, but that gave no clue. Then, as I looked through the telephone lists, I discovered that there was a bookstore kept by a man of each name. Then I understood. It is a simple plan for throwing off shadowers."

"You mean that Mr. Hoff goes to a different bookstore each day to leave a code message?"

"That's it. The spy who gets the messages each morning calls him up by 'phone, mentioning just the one word. From that Mr. Hoff knows just where to go, concealing the message in a book before agreed upon."

"The fifth book," interrupted Dean.

"Not always," explained Fleck. "It depends on whether there are five letters in the name telephoned. I have located and copied several more of the messages."

"But who gets the messages he leaves? Who takes them away from the bookshops?" asked Jane, mindful of her own failure in that respect.

"It's a girl, or rather two girls together, though possibly only one of them is in the plot. Very likely the other may not know what her companion is doing."

"To whom does this girl take them?"

"That is still a mystery," said the chief. "We have ascertained who the girl is, where she lives. Her actions have been watched and recorded for every hour in the twenty-four for the last three days, and yet we don't know what she does with these messages. Carter has a theory—tell us about it, Carter."

"In accordance with instructions," began Carter, as if he was making out a report, "I had operatives K-24 and K-11 shadow the party suspected. On two different occasions they followed her to a bookstore and back home again. She was accompanied on one occasion by her younger sister. Each time she went directly home and stopped there, neither she nor her sister coming out again, and no person visiting the apartment, but—"

"Here's the interesting part," interrupted Fleck.

"On both occasions within a couple of blocks of the bookstore she passed a man with a dachshund. She did not speak to the man, but each time she stopped to pet the dog."

"Was it the same man both times?" asked Dean.

"Apparently not," replied Carter, "but it may have been the same dog. Dachshunds all look alike."

"Go on," said the chief.

"Now my theory is that that girl was instructed to walk north until she met the man with the dog. I'll bet anything that code message went under the dog's collar. The next time she gets a message I'm going to get that dog."

"It seems preposterous," scoffed Dean.

"Rather it shows," said Fleck, "that these spies all suspect they are being watched, and that they resort to the most extraordinary methods of communication to throw off shadowers. They have used dachshunds before. There's a New England munition plant to which they used to send a messenger each week to learn how their plans for strikes and destruction were progressing. They put a different man on the job each time to avoid stirring up suspicion. At the station there would always be two children playing with a dachshund. The spy would simply follow them as if casually, and they would lead him to a rendezvous with the local plotters. Now, Miss Strong," he said, turning to Jane, "I brought you down here for two reasons. First, to give you an inkling of how important your task is, and second, to ask you to undertake still another task for us. Are you still willing to help?"

"More than ever," said the girl firmly.

"The one disappointment is that we are getting no evidence whatever to involve or incriminate young Hoff. To-morrow, while he and his uncle are away on their usual auto trip, I am going to have the apartment thoroughly searched."

Jane's face blanched. She recalled what a strain it had been on her nerves the day she watched on the roof while Dean installed the dictograph. She felt hardly equal to the task of ransacking desks and drawers.

"There will be no one at home but the old servant. She can be easily disposed of. It is imperative that the search be made at once. There is evidence that what they are planning—evidently some big coup—is nearing the time for its execution. We must find it out in order to thwart them. I have got to know what old Hoff meant by the 'wonder-worker!' He said that it was nearly ready. I suspect that it is some new engine of destruction. We must prevent any disaster to transports or munition factories, if that's what they have in mind."

"You think it's a bomb plot?" asked Jane.

"I don't know what it is. These empire-mad fools stop at nothing. Nothing is sacred to them, women, children, property. With fanatical energy and ability they commit murders, resort to arson, use poisons, foment strikes, wreck buildings, blow up ships, do anything, attempt anything to serve the Kaiser. Karl Boy-ed spent three millions here in America in two months, and Von Papen a million more. What for? Ten thousand dollars to one man to start a bomb factory, twenty-five thousand dollars to another to blow up a tunnel. Millions on millions for German propaganda was raised right here, and it is far from all spent yet. We've got to find out what the wonder-worker is and destroy it before it destroys—God knows what."

"Very well," said Jane with quiet determination, "I'll search their apartment."

"No, not that," said the chief, "I'll send some fake inspectors to test the electric wiring, and they'll do the searching. I do not know for sure that the Hoffs suspect you of watching them, but I'm taking no chances. It will be just as well for you and Dean to be out of the way to-morrow all day, so that you will have an alibi. Germany's secret agents are suspicious of everybody. They do not even trust their own people. What I want you and Dean to do is to try to follow the Hoffs and see where they go. I don't want to use the same persons twice to trail them as they may get suspicious."

"I can easily do that," said Jane, feeling relieved. "I'll tell Mother I want our car for all day."

"No, don't use your own car. They might recognize it. I'll provide another one. They gave two of my men the slip last week somewhere the other side of Tarrytown. Let's hope they are not so successful this time."

"But won't they recognize me?"

"Not if you disguise yourself with goggles and a dust coat. Dean can make up, too. He had practice enough at college, eh, Dean?"

Jane turned to look interestedly at Dean, who had the grace to color up. She was right then. He was a college man, working in the secret service not for the sake of the job but for the sake of his country.

"Of course I can disguise myself too," she said enthusiastically, a new zest in her work asserting itself, now that she knew her principal co-operator was probably in the same social stratum as herself.

"You can rely on us, Chief," said Dean, as they left the office together. "We'll run them down."

As they emerged into Broadway and turned north to reach the subway at Fulton Street, Dean, with a warning "sst," suddenly caught Jane's arm and drew her to a shop window, where he appeared to be pointing out some goods displayed there. As he did so he whispered:

"Don't say a word and don't turn around, but watch the people passing, in this mirror here—quick, now, look."

Jane, as she was bidden, glanced, at first curiously and then in recognition and amazement, at a tall figure reflected in the mirror, as he passed close behind her. It was a man in uniform. Regardless of Dean's warning she turned abruptly to stare uncertainly at the military back now a few paces away.

"Did you recognize him?" cried Dean.

"It—it looked like Frederic Hoff," faltered the girl.

"It was Frederic Hoff," corrected her companion, "Frederic Hoff in the uniform of a British officer, a British cavalry captain!"



CHAPTER IX

THE PURSUIT

Masked by an enormous pair of motor goggles and further shielded from recognition by a cap drawn down almost over his nose, Thomas Dean in a basket-rigged motorcycle impatiently sat awaiting the arrival of Jane Strong at a corner they had agreed upon the evening before. He had been particularly insistent that Jane should be on hand at a quarter before eight. He had learned by judicious inquiries that always on Wednesdays—at least on the Wednesdays previous—the Hoffs had started off on their mysterious trips at eight sharp. His intention was to get away ahead of them and pick them up somewhere outside the city limits.

Jane had promised that she would be on hand promptly. Once more he looked impatiently at his watch. It lacked just half a minute of the quarter, but there was no sign of his fellow operative. The only person visible in the block was a boy strolling carelessly in his direction. With a muttered exclamation of annoyance Dean restored his watch to his pocket, debating with himself how long he ought to wait and whether or not he had better wait if she did not appear soon. Very possibly, he realized, something entirely unforeseen might have detained her or have prevented her coming. Perhaps her family had doubted her story that she was going off on an all-day motor trip with a friend? Maybe their suspicions had been aroused by his having reported sick? He had almost decided to go on alone when he observed that the boy he had seen approaching was standing beside the motorcycle.

"Good morning, Thomas," said the boy, a little doubtfully, as if not quite sure that it was he.

Dean gasped in astonishment. The boy's voice was the voice of Jane. Laughing merrily at his amazement and discomfiture, she climbed into the seat beside him, asking:

"How do you like my disguise?"

"It's great," he cried. "You fooled me completely, and I was expecting you."

"When Chief Fleck said I ought to disguise myself for fear that the Hoffs already suspected me, I happened to remember these clothes. I had them once for a play we gave in school."

"But you don't even walk like a girl."

Jane laughed again.

"I practised that walk for days and days. When I first put on this suit my brother hooted at the way I walked. He said no girl ever could learn to walk like a boy. I made up my mind I'd show him."

"But your hair," protested Dean, almost anxiously. Even if he was just now assuming the humble role of chauffeur he still was an ardent admirer of such hair as Jane's, long, black and luxurious.

"Tucked up under my cap," laughed the girl, "and for fear it might tumble down, I brought this along. It's what the sailor boys call a 'beanie,' isn't it?"

As she spoke she adjusted over her head a visorlike woolen cap that left only her face showing.

"But your mother—didn't she wonder about your wearing those clothes?"

"She was in bed when I left. All she caught was just a glimpse of me in Dad's dust coat, and that came to my ankles. I wore it until I was a block away from the house. Will I do?"

"You can't change your eyes," said Dean boldly, that is boldly for a chauffeur, but he knew that Jane knew he wasn't a chauffeur except by choice, so that made it all right.

"I couldn't well leave them behind. I understood that I was to have a lot of use for my eyes to-day."

"Yes, indeed, you very likely will."

"Do you know I hardly recognized you at first and was almost afraid to speak? I had expected to find you in a car. What was the idea of the motorcycle?"

"It was Chief Fleck's suggestion. The Hoffs will be motoring. People in a car seldom pay any attention to motorcyclists. If we were to follow them in a motor they'd surely notice it. Last week they managed to dodge the people the Chief assigned to trail them. Maybe as two dusty motorcyclists we'll have better luck."

"I hope so. Where do you intend waiting to pick them up?"

"Getty Square in Yonkers is the best place. Everybody going north goes that way. I can be tinkering with the machine while you keep watch for them. They will not be apt to suspect a pair of Yonkers motorcyclists. There's no danger of missing them."

"Did you tell the Chief about seeing Mr. Hoff in that uniform?"

"Of course. He did not seem even surprised. Some one had reported to him already that there was a German going about in British uniform."

"What had he heard? What was the man doing?" questioned Jane anxiously. Even though she believed Frederic Hoff an alien enemy, even though she was all but sure that he was a murderer, she kept finding herself always hoping for something in his favor. He seemed far too nice and entertaining to be engaged in any nefarious, underhanded, despicable machinations. Yet she had seen him masquerading as a British officer. She could not doubt the evidence of her own eyes.

"What happened was this," continued Dean. "A woman—one of the society lot—was driving down Park Avenue day before yesterday morning in her motor. It had been raining, and the streets were muddy. At one of the crossings a British officer stopped to let the car pass. One of the wheels hit a rut, and his uniform was all splashed with mud. He burst into a string of curses—German curses."

"He cursed in German?" cried Jane.

"Sure," said Dean. "On the impulse of the moment he forgot his role and revealed his true self—an arrogant Prussian officer."

"What did the woman do?"

"Reported him to the first policeman she met, but by that time he had vanished, of course."

"What did Chief Fleck think about it?"

"He didn't seem to take the story seriously."

"Do you suppose it could have been Mr. Hoff?"

"It must have been he, or one of his gang, at any rate. I don't see why the Chief does not order his arrest at once. He is far too dangerous to be at large."

"There's no real evidence against him yet," protested Jane, "not against the young man, at least."

"Didn't we both see him in British uniform?"

"Yes," admitted the girl.

"Well, that's proof, isn't it? A man with a German name in British uniform in wartime can't be up to any good."

"Still we have no actual evidence against him. We don't know what he was doing."

"I'd arrest him then for murder and get the evidence that he is a spy afterward. It would be easy to fasten the murder of K-19 on him. There's no doubt that he did that."

"Has a witness been found?" asked Jane with a quick catch of the breath. Somehow she never had been able to persuade herself that the man next door, whatever else he might be, had really committed that brutal murder.

"No, there's no actual witness, but it could be proved by circumstantial evidence. K-19, the man whose work you took up, had instructions to shadow young Hoff to his home. At two in the morning he relieved another operative. At three you yourself saw him shadowing Hoff."

"I saw two men on the sidewalk," corrected Jane. "One of them was Frederic Hoff. I did not see the other distinctly enough to identify him. I saw no murder. I merely saw the two of them run around the corner."

"Look here," said Dean sharply, not wholly succeeding in suppressing a note of jealousy in his tones, "I believe you are trying to shield Frederic Hoff. What is he to you? Has he won you over to his side?"

"You've no right to say such things to me," cried Jane, nevertheless coloring furiously. "I've seen the man only three or four times. I am working just as hard as you are to prove that he is a German spy, if he is one. I am only trying to be fair. I know nothing that convicts him of murder. Any testimony I could give would not prove a single thing."

"Certainly not, if that's the way you feel about it," snapped Dean.

After that they rode along together in silence, each busy with thoughts of their own. Dean was cursing himself for having let his enthusiasm to be of service to his government lead him into such circumstances. He felt that his chauffeur's position handicapped him in his relations with Jane, to whom he had been strongly attracted from the beginning. The son of a distinguished American diplomat, he had been educated for the most part in Europe. Friends of his father, when he had offered his services to the government, had convinced him that his knowledge of German and French would make him most useful in the secret service. Reluctantly he had consented to take up the work, and as he had gone further and further into it and had realized the vast machinery for surreptitious observation and dangerous activity that the German agents had secretly planted in the United States, he had become fascinated with his occupation—that is, until he met Jane Strong.

His association with her under present circumstances was fast becoming unbearable. Even though he was aware that she knew he was no ordinary chauffeur, he loathed the necessity of having to wear his mask in the presence of her family. He wanted to be free to come to see her, to send her flowers and to go about with her. For him to take any advantage of their present intimate relations to court her seemed to him little short of a betrayal of his government, yet at times it was all he could do to keep from telling her that he adored her. Love's sharp instincts, too, had made him realize that Jane was already beginning to be attracted by the handsome young German whom they were seeking to entrap, and the knowledge of this fact filled him with helpless rage and jealousy.

Jane, too, angered and insulted at first by Dean's outburst, had been endeavoring to analyze her own conduct. Candor reluctantly compelled her to admit that each time she met Frederic Hoff she had found herself coming more and more under his spell. He had a wonderful personality, talked entertainingly and ever exhibited an innate gallantry toward women in general, and herself in particular, which Jane had found delightfully interesting. Though she had undertaken wholeheartedly to try to get evidence against him, she was forced to admit to herself now that she was secretly delighted that there had been nothing damaging found as yet, so far as he was concerned, beyond the one fact that he had been in British uniform.

In vain she marshalled the circumstances about him, trying to make herself hate him. He was a German, she told herself. He was an enemy of her country. He lived with a man who had been proved to be a spy. He surreptitiously associated with American naval officers. The dictograph told her that nightly his uncle and he in the seclusion of their home toasted America's arch enemy, the German Kaiser. More than likely, too, her reason told her, he was a murderer. She ought to hate, to loathe, to despise him, and yet she didn't. She liked him. Whenever he approached she could feel her heart beating faster. She looked forward after each meeting with him to the time when she would see him again. What, she wondered, could be the matter with her? Assuredly she was a good patriotic American girl. Why couldn't she hate Frederic Hoff as she knew he ought to be hated?

She was still puzzling over her unruly heart when they reached Getty Square, and Dean brought the motorcycle to a stop in one of the side streets overlooking Broadway. Dismounting, he looked at his watch and made a pretense of tinkering with the engine, while Jane kept a sharp lookout on the main thoroughfare, by which they expected the Hoffs to approach. Ten minutes, twenty minutes, more than half an hour they waited, anxiously scanning each car as it passed.

"I can't understand it," said Dean. "They should have been here at least twenty minutes ago. I am going to 'phone Carter. He will know what time they started."

He had hardly entered an adjacent shop before Jane, still keeping watch, saw the Hoffs' car flash by, going rapidly north. Quickly she sprang out and ran into the store. Dean saw her coming and left the telephone booth, his finger on his lips in a warning gesture.

"Don't bother to 'phone," cried the girl, misunderstanding his meaning—and thinking only that he was trying to prevent her naming the Hoffs. "Come, let's get started."

Without speaking he hurried from the store and got the motorcycle under way.

"Have they passed?" he whispered then.

"Just a moment ago."

Silently he gathered up speed, racing in the direction the Hoffs' car had gone, not addressing her again until perhaps two miles from Getty Square they caught up with it close enough to identify the occupants, whereupon he slowed down and followed at a more discreet interval.

"Be careful about speaking to me when there's any one about," he warned Jane, almost crossly. "Those clothes make you look like a boy, and your walk is all right, but your voice gives you away. Did you see that clerk in the store look at you when you spoke to me? I tried to warn you to say nothing."

"I'll be careful hereafter," said Jane humbly, still depressed by her recent estimate of herself. "I forgot about my voice."

Mile after mile they kept up the pursuit without further exchange of conversation. As they passed through various towns along the road Dean purposely lagged behind for fear of attracting attention, but always on the outskirts he raced until he caught up close enough again to the car to identify it, then let his motorcycle lag back again. Thus far the Hoffs had given no indication of any intention to leave the main road.

As the cyclists, far behind, came down a long winding hill on which they had managed to catch occasional glimpses of their quarry, Dean, with a muttered exclamation, put on a sudden burst of speed. At a rise in the road he had seen the Hoffs' car swing sharply to the left. Furiously he negotiated the rest of the hill, arriving at the base just in time to see them boarding a little ferry the other side of the railroad tracks. While he and Jane were still five hundred yards away the ferryboat, with a warning toot, slipped slowly out into the Hudson.

In blank despair they turned to face each other. The situation seemed hopeless. They dared not shout or try to detain the boat. That surely would betray to the Hoffs that they were being followed. Despondently Dean clambered off the motorcycle and crossed to read a placard on the ferryhouse.

"There's not another boat for half an hour," he said when he returned. "They have gained that much on us."

"Perhaps we can pick up their trail on the other side of the river," suggested Jane. "There are not nearly so many cars passing as there would be in the city."

"We can only try," said Dean gloomily.

"At least we know where to pick up their trail the next time."

"Damn them," cried Dean, "I believe they suspect that they may be followed and time their arrival here so as to be the last aboard the ferryboat. That shuts off pursuit effectually. They make this trip every week. I wouldn't be surprised if they have not fixed it with the ferry people to pull out as soon as they arrive. A two-dollar bill might do the trick. I'd give five thousand right now if we were on the other side of the river. It's the first time—the only time I've ever failed the Chief."

"Never mind," said Jane consolingly, "why can't we be waiting for them at the other side next week when they come up here? They're not apt to suspect motorcyclists they meet up here with having followed them."

"Perhaps next week will be too late."

"I wonder where they are headed for," said the girl, looking across at the rapidly receding boat. "Why, look! What are those buildings over there?"

"That's West Point," Dean exclaimed, noting for the first time where they were.

"West Point!" she echoed in amazement.

What mission could the Hoffs have that would take them to the United States Government military school was the question that perplexed them both. Could it be that the web of treachery and destruction the Kaiser's busy agents were weaving had its deadly strands fastened even here—at West Point?



CHAPTER X

CARTER'S DISCOVERY

"It's the young man I'm after," said Chief Fleck. "We have the goods on old Hoff, but we have nothing incriminating against Frederic yet. The very fact that he holds aloof from his uncle's activities makes me think he is engaged in more important work. He's just the type the Germans would select as a director."

"That's right," said Carter despondently. "There's nothing except the fact that Dean and the girl think they saw him in British uniform. Why didn't they follow and make sure?"

"They tried to," said the chief, "but he gave them the slip. I'm inclined to believe they were mistaken. More than likely it was a chance resemblance. Lots of Britishers of the Anglo-Saxon strain look much like Germans, and a uniform makes a big difference in a man's appearance. I'm afraid there's nothing in that."

"But both saw the man—Dean and Miss Strong," protested Carter.

"The trouble is," observed Fleck, "that Dean is getting infatuated with the girl. A young man in love is not a keen observer. Anything she thinks she has seen he'll be ready to swear to. I hope the girl keeps her head. Lovers don't make good detectives."

"I have watched them together," said Carter. "I'll admit he's struck on her, but I don't think she cares a rap for him. She's too keenly interested in Frederic Hoff."

"What do you mean by that?" asked the chief sharply.

"You can depend on her all right. She's patriotic through and through. She's the kind that would do her duty, no matter what it cost her. All I meant is that Hoff's the type that interests women. He's got a way about him. The fact that he's a spy, in peril most of the time, gives him a sort of halo. I never knew a daring young criminal yet that didn't have some woman, and often several of them, ready to go the limit for him. All the same, I'm sure we can trust Miss Strong."

"We've got to," growled Fleck, "for the present at any rate. Is everything fixed for the search this afternoon? What have you done to get the superintendent out of the way? He's not to be trusted. His name is Hauser."

"I've got him fixed. Jimmy Golden, my nephew, who has helped us in a couple of cases, is a lawyer. He has telephoned to Hauser to come to his office this afternoon."

"Suppose he doesn't go?"

"He'll go all right. Jimmy 'phoned him that it was about a legacy. That's sure bait. Jimmy will make Hauser wait an hour, then keep him talking half an hour longer. That will give us plenty of time."

"Then there's the woman—the servant, Lena Kraus."

"She goes to the roof every Wednesday while the Hoffs are away to signal. Other days they apparently do the signalling themselves in some way we haven't caught on to yet. She always goes up about three o'clock and—"

"Suppose she comes down unexpectedly and catches you? We can't have that happen. That would put them on their guard."

"She won't surprise us. I've got a trick up my sleeve for preventing that."

"Go to it, then," said the chief, and Carter went on his way rejoicing.

Ever since he had been informed that the search of the Hoffs' apartment was to be intrusted to him Carter had been in a state of exuberant delight. He fairly revelled in jobs that required a disguise and he welcomed the opportunity it gave him and his assistants to don the uniform of employees of the electric light company. He even made a point of arriving that afternoon at the apartment house in the company's repair wagon, the vehicle having been procured through Fleck's assistance.

"There's a dangerous short circuit somewhere in the house," he announced to the superintendent's wife.

"My husband isn't here," she answered unsuspectingly. "Do you know where the switch-boards are?"

"We can find them," said Carter. "We'll start at the top floor and work down."

Always thorough in his methods of camouflage he actually did go through several apartments, making a pretense of inspecting switch-boards and wiring, all the while keeping watch for the time when old Lena went to the roof. The moment she had entered the elevator to ascend with her basket of linen, Carter and his aides were at the Hoff door. Equipped with the key Dean had manufactured they had no difficulty in entering.

"Bob," said Carter to one of his men, "we haven't much time, and there's a lot to be done. You take the servant's room and the kitchen, and you, Williams, take the old man's quarters. I'll take care of the young man's bedroom, and we'll tackle the living room and dining room later."

Thoroughly experienced in this sort of work all three of them set at once to their tasks. Carter, standing for a moment in the doorway, surveyed Frederic Hoff's quarters, taking in all the details of the furnishings. Both the sitting room and the bedroom adjoining were equipped in military simplicity, with hardly an extra article of furniture or adornment, chairs, tables, everything of the plainest sort. Moving first into the bedroom, Carter quickly investigated pillows and mattress, but in neither place did he find what he sought, evidence of a secret hiding place. He rummaged for a while through the drawers of two tables, carefully restoring the contents, but discovering nothing that aroused his suspicions. The books lying about on the tables and on shelves he examined one by one, noting their titles, examining their bindings for hidden pockets, holding them up by their backs and shaking the leaves. There was nothing there. Lifting the rugs and moving the furniture about he made a careful survey of the flooring, seeking to find some panel that might conceal a hiding place. Once or twice in corners he went so far as to make soundings but apparently the whole floor was intact. His search in the bath room was equally profitless, and at last he turned to the clothes press. As he opened the door an exclamation of amazement burst from his lips.

There, concealed behind some other suits, was the complete outfit of a British cavalry captain.

"That's one on the Chief," he said to himself. "It must have been Hoff that Dean and Miss Strong saw. I wonder where he got it?"

With a grim smile of satisfaction he devoted himself to going carefully through all the pockets and over all the seams of the clothing in the closet. He even felt into the toe of the shoes and examined the soles. There was nothing to be found anywhere, but he felt satisfied. The uniform in itself was to his mind damning proof of the young man's occupation.

No explanation that could be given by a young man of German name, even though he was American-born, or had an American birth certificate, could possibly account for his having a British uniform. It was prima facie evidence that Frederic Hoff was a spy. What puzzled Carter most was how Hoff managed to smuggle the uniform in and out of the apartment without being observed. For more than two weeks now every parcel that had arrived at the house of the Hoffs had been searched before it was delivered. The house had been constantly under the strictest surveillance. It was out of the question for him to have worn the uniform in or out as it could not be easily concealed under other clothing.

"There's somebody else in this place in league with the Hoffs," he muttered to himself. "I wonder who it can be."

He looked at his watch. The old servant had been out now nearly half an hour. She was likely to return at any moment. He must work quickly. Swiftly he went through the dresser drawers but without satisfactory result. There was no time for him to do more. He hastened into the living room and summoned his aides.

"Find anything, Bob?" he asked.

"Not a thing."

"Beat it up to the roof," he directed. "Have you those field glasses with you?"

"Sure," replied the operative, "and the handkerchiefs, too."

"All right. Get up there before she starts down. Begin putting up handkerchiefs and appear to be watching the river. That will mix her up so she will not know what to do. She will not dare to leave the roof while you are there. When we're through I'll send the elevator man up for you with the message that we have found the short circuit."

He turned to the other operative.

"Find anything, Williams?"

"Only this."

Carter's face brightened as his assistant held out to him two copies of an afternoon newspaper. In each of them a square was missing where something had been cut out.

"I found them in the waste-paper basket by the old man's desk," the man explained, "and there was some ashes there—ashes of paper—as if he had burned up something. Maybe it was what he cut out of those papers. I could not tell."

"We've got to get copies of those papers at once and see what it was. Come on, I'm going to take them to the Chief. We can get the papers on the way down."

Calling the other operative from the roof, before he even had had time to attract the attention of Lena Kraus by his activities, they hastened back to the office, where Fleck and Carter together scanned the two papers from which the clippings had been taken.

"Why," said Carter disappointedly, "it is just a couple of advertisements he cut out—advertisements for a tooth paste. There's nothing in that."

"Don't be too sure," warned Fleck. "If a man cuts out one tooth-paste advertisement, the natural presumption would be that he wished to remind himself to buy some. When he cuts out two, he must have some special interest in that particular tooth paste. We'll have to find out what his interest is."

"Maybe he owns it," suggested Carter.

"Perhaps," said Fleck, as he began studying the advertisements, "but it would not surprise me if these advertisements contained some sort of code messages."

"Messages in advertisements," exclaimed Carter incredulously.

"Why not? The Germans have hundreds of spies at work here in this city and all over the country. What would be an easier method of communicating orders to them than by code messages concealed in advertising. They have done it before. When the German armies got into France they found their way placarded in advance with much useful information in harmless looking posters advertising a certain brand of chocolate. I'd be willing to bet that every one of these advertisements carries a code message. I've noticed that these advertisements, all peculiarly worded, have been running for some time. I never thought of hooking them up with German propaganda, but, see, it is a German firm that inserts them."

Carefully he cut out the two advertisements and laid them side by side on his desk. Turning to Carter he said:

"Go at once to see Mr. Sprague, the publisher of this paper. Get him to give you a copy of each paper that has contained an advertisement of this sort in the last six months. Find out what agency places the advertising. Tell him I want to know. He'll understand. We have worked together before."

Alone in his office, Fleck bent with wrinkled brow over the first of the two advertisements, which read:

REMEMBER

Please, that our new paste, DENTO, will stop decay of your teeth. Sound teeth are passports to good health and comfort. Now, no business man can risk ill health. It is closely allied with failure. The teeth if not watched are quickly gone.

USE DENTO

A genuine, safe, pleasing paste for the teeth, prepared and sold only by the Auer Dental Company, New York.

He tried all the methods of solving cipher letters that he thought of. He drew diagonals this way and that across the advertisement. He tried reading it backward. He tried reading every other word, every third word, both backward and forward. Nothing that he did revealed any combination of words that made sense.

"Passports," he muttered to himself, "that's it. If there is a message there it must be something about passports."

In despair he turned to the other advertisement. It read:

DON'T

Forget it is imperative for one and all to use cleansing agents on teeth that leave no bad results.

"Ship more of that wonder-working paste immediately. Workers, employers, wives, all ready to commend it. Friday's supply gone," writes a druggist to whom a big shipment was made last week.

USE DENTO

A genuine, safe, pleasing paste for the teeth, prepared and sold only by the Auer Dental Company, New York.

Fleck's eyes gleamed with satisfaction as he read this advertisement and caught the phrase "wonder-working." He felt sure now that he was on the right track. He recalled that Jane Strong over the dictograph had heard old Hoff speak of something that he called the "wonder-worker." As soon as Carter returned with the other advertisements that had been appearing he felt positive that he would be able to unravel the cipher. Two words he was sure of—"passports" and "wonder-working." One footprint does not lead anywhere, but two do, and given three footprints, a pathway is indicated.

His telephone rang sharply. He turned to answer it, suspecting it must be Carter with some message about the papers he had sent for.

"Hello," he called.

"Hello," came a faint voice, as if the speaker were using long distance, and had a bad connection, "is this Fleck?"

"Yes, Fleck," he answered, "who is this?"

"Dean speaking," came the voice faintly.

"Dean," cried Fleck, excitedly, "yes, yes. What is it, Dean?"

He had not expected to hear any results from the expedition that Dean and Jane Strong had undertaken until late in the afternoon after the Hoffs returned. The fact that Dean was calling him up now would seem to indicate that something of importance had happened.

"I'm telephoning from a doctor's house near Nyack," said Dean.

"What's that? Speak louder."

"I'm here in Doctor Spencer's office near Nyack with a broken arm," Dean continued. "We've had an accident. Somebody's auto smashed into us, I guess."

"Miss Strong? Where is she? Is she hurt?" asked the chief anxiously.

"I don't know. She has vanished."

Jane Strong vanished! The chief's figure became suddenly tensed. That it was more than a mere automobile accident he felt certain now. Shadowing the Hoffs was an occupation that seemed unusually perilous. There flashed into his mind the fate of K-19—murdered almost at the Hoffs' door. And now two more of his operatives, one disabled and the other mysteriously missing.

"Quick," he said over the 'phone. "Tell me briefly just what happened. Speak as loudly as you can."

"We got half an hour behind at the West Point Ferry," Dean's voice went on, still weak and low as if he were speaking with difficulty. "We had some trouble getting started on the trail again but finally succeeded. We were dashing along about ten or twelve miles south of West Point when an automobile coming out of a cross road crashed right into us. It must have knocked me unconscious. I didn't remember anything more till I found myself here. I came to as the doctor was setting my arm. I 'phoned as soon as they would let me."

"Who brought you there?"

"I don't know. All they know here was that some couple in an automobile left me here. They said they passed just after an auto hit my motorcycle. They said the auto didn't stop."

"And Miss Strong—did they say anything about her?"

"Not a word. The people here were under the impression I was riding alone."

"All right," said the chief. "I'll get some one up there at once to look after you and pick up any clues."

As he hung up the 'phone, his forehead wrinkled into little lines of absorbed concentration. He sat at his desk for fully five minutes almost motionless, trying to figure it out. What did the accident to Dean signify? How was the sudden disappearance of Jane Strong to be accounted for? Had she fled from the scene after Dean was disabled, fearing that her name might be coupled with his in an account of the accident? It did not seem like the sort of thing she would do. The impression she had made on him was that of a girl of high resolve who would be apt to carry through anything she undertook, cost what it may. Yet what could have happened to her? If she, too, had been injured, why was she not with Dean? If she was not injured, why had she not communicated with the office? Who were the couple that had brought Dean to the doctor's office? Why had not the doctor taken their names and addresses?

What part had the Hoffs played in the accident? Had they purposely run down the motorcycle? If they had found out they were being shadowed they would not have hesitated, he felt sure, to resort to such murderous tactics. Had they not already one dastardly murder to their record? He must find out when the Hoffs arrived home. They would not be due for an hour or two, but he would caution the operatives watching the house to keep more vigilant watch. Reaching for his 'phone he called up the head-quarters of the operatives.

"Report to me at once," he said to the operative who answered his call, "the minute the Hoffs have arrived home."

"The old man is home now," the operative answered.

"What's that?" cried Fleck.

"He came in alone five minutes ago on foot. The young man is not home yet with the automobile."

"Let me know as soon as he arrives," said Fleck curtly, turning away from the 'phone.

He was more perplexed than ever. What could have happened? Where was young Hoff with the motor? Where was Jane Strong? Why had she disappeared after Dean had been hurt? How had she vanished? The Hoffs' affairs had assuredly taken a new and bothersome turn, over which Fleck sat puzzling many minutes.

Where was Jane Strong? In the answer to that question, he decided at length, lay the crux of the whole situation.



CHAPTER XI

JANE'S ADVENTURE

For more than two hours Thomas Dean and Jane had been vainly circling about West Point on their motorcycle, striving to pick up some clue that would put them once more on the trail of the Hoffs' car. They had not dared to ask too many questions of any one near the ferry, fearful lest the people they were pursuing might have a guard posted there to warn them in case of a possible pursuit, yet cautious inquiries seemed to indicate that all the automobiles on the ferryboat which had preceded had been headed to the north.

"There's only one thing we can do," Dean had said despondently. "We have got to run out each road we come to until we reach some shop or garage where the people would be likely to have noticed the Hoffs. They may have stopped somewhere, or we may meet some one coming toward us who will remember having passed them."

"It seems like a wild-goose chase," said Jane, "but I suppose there is nothing else to do."

The strain of their bitter disappointment was telling on both of them. Each felt inclined to blame the other for their having fallen so far behind. They rode along in silence, their nerves becoming more and more keyed up as their hopes grew less. At garage after garage they paused to question the employees.

"Did a big gray car with two men, an old man with a beard and a young man driving, pass this way about an hour ago?"

"I don't remember any such car," was the invariable answer.

Time and time again they repeated their query, wording it always the same, except for lengthening the interval of time in which the car might have passed, for the afternoon was rapidly passing. In their circuit they had now reached the roads pointing to the southward.

"We'll try this one more garage," said Dean, as they approached a wayside shed bearing a large sign "Gasoline."

"I fear it is only wasting time," said Jane wearily.

"Don't you want the Hoffs caught?" snapped her companion.

"Of course I do," she retorted heatedly, "but I don't see you catching them."

"I believe you are half glad of it," snarled her escort as he brought the machine to a stop and repeated his usual question.

"Sure there was a car with two men in it like you describe passed here," the man replied to their amazement and delight. "They stopped here for gas, as they generally do. About three hours ago, I guess it musta been."

Dean shot a triumphant glance at Jane.

"An old man with a gray beard and a smooth-shaven young man driving—does that describe them?" he repeated.

"That's them," said the garage proprietor. "They come through here every few days, always about the same time."

"Where do they go?" questioned Dean eagerly, feeling at last that the scent was growing hot.

The man shook his head in a puzzled way.

"I've often wondered about that. They're always heading south and appear to be in a powerful hurry, but the funny part of it is I ain't never seen them coming back."

"Do you know their names?"

"No, I can't say I do, though it seems as if I'd heard one of them called Fred. I can't say which it was."

"Do they always come by on the same day—on Wednesday?" asked Jane, forgetful once more of Dean's warning to let him do the talking lest her voice should betray her sex.

"Come to think of it," said the man, apparently noticing nothing unusual, "I guess it always is on a Wednesday they come by."

"Is the number of their car anything like this?" asked Dean, exhibiting an entry in his notebook.

"I couldn't say," said the man, studying the figures. "I know it is a New York license, and the number ends with two nines like this one does. What might you be wanting them for?"

He spoke to a cloud of dust, for Dean had started up the motorcycle before he finished speaking and already was speeding away.

"Where now?" asked Jane.

"I don't know," he answered frankly, "I only know we are going the direction the Hoffs went, and I want to gain on them before they get too far ahead. The chap back there had told us all he knew and was beginning to get curious, so I thought it better to vamoose."

"It's funny about his never seeing them coming back."

"Probably there is nothing mysterious about that. I have a notion they always come up one side the river and down the other, taking the 125th Street ferry home. That would not be a bad plan to help them in eluding too curious observers. All these German spies are trained to leave as blind a trail behind them as possible. The thing we have got to discover is what brought them up here. We've just got to find out their destination."

"I am afraid there is little chance of our doing that," insisted Jane. "We've nothing to go on."

"We've learned something. We know that their destination is somewhere between here and Fort Lee on this side of the river. That narrows down the search considerably. That's more, too, than anybody else that the Chief has had on their trail has learned. Something tells me that we are getting warm right now. Obviously the place they come to must be nearer West Point than it is New York. They would hardly take too roundabout a course, even for the sake of hiding their tracks. Keep a sharp lookout for tire tracks leaving the main road."