.

CHAPTER I 

CUP AND LIP

The case in question concerned a letter in a yellow envelope, which was dumped along with other incoming mail upon one of the many long tables where hundreds of women and scores of men sat opening and reading thousands of letters for the Bureau of P. C.--whatever that may mean. 

In due course of routine a girl picked up and slit open the yellow envelope, studied the enclosed letter for a few moments, returned it to its envelope, wrote a few words on a slip of paper, attached the slip to the yellow envelope, and passed it along to the D. A. C.--whoever he or she may be. 

The D. A. C., in course of time, opened this letter for the second time, inspected it, returned it to the envelope, added a memorandum, and sent it on up to the A. C.--whatever A. C. may signify. 

Seated at his desk, the A. C. perused the memoranda, glanced over the letter and the attached memoranda, added his terse comment to the other slips, pinned them to the envelope, and routed it through certain channels which ultimately carried the letter into a room where six silent and preoccupied people sat busy at six separate tables. 

Fate had taken charge of that yellow envelope from the moment it was mailed in Mexico; Chance now laid it on a yellow oak table before a yellow-haired girl; Destiny squinted over her shoulder as she drew the letter from its triply violated envelope and spread it out on the table before her. 

A rich, warm flush mounted to her cheeks as she examined the document. Her chance to distinguish herself had arrived at last. She divined it instantly. She did not doubt it. She was a remarkable girl. 

The room remained very still. The five other cipher experts of the P. I. Service were huddled over their tables, pencil in hand, absorbed in their several ungodly complications and laborious calculations. But they possessed no Rosetta Stone to aid them in deciphering hieroglyphics; toad-like, they carried the precious stone in their heads, M. D.! 

No indiscreet sound interrupted their mental gymnastics, save only the stealthy scrape of a pen, the subdued rustle of writing paper, the flutter of a code-book's leaves thumbed furtively. 

The yellow-haired girl presently rose from her chair, carrying in her hand the yellow letter and its yellow envelope with yellow slips attached; and this harmonious combination of colour passed noiselessly into a smaller adjoining office, where a solemn young man sat biting an unlighted cigar and gazing with preternatural sagacity at nothing at all. 

Possibly his pretty affianced was the object of his deep revery--he had her photograph in his desk--perhaps official cogitation as D. C. of the E. C. D.--if you understand what I mean?--may have been responsible for his owlish abstraction. 

Because he did not notice the advent of the yellow haired girl until she said in her soft, attractive voice: 

"May I interrupt you a moment, Mr. Vaux?" 

Then he glanced up. 

"Surely, surely," he said. "Hum--hum!--please be seated, Miss Erith! Hum! Surely!" 

She laid the sheets of the letter and the yellow envelope upon the desk before him and seated herself in a chair at his elbow. She was VERY pretty. But engaged men never notice such details. 

"I'm afraid we are in trouble," she remarked. 

He read placidly the various memoranda written on the yellow slips of paper, scrutinised! the cancelled stamps, postmarks, superscription. But when his gaze fell upon the body of the letter his complacent expression altered to one of disgust! 

"What's this, Miss Erith?" 

"Code-cipher, I'm afraid." 

"The deuce!" 

Miss Erith smiled. She was one of those girls who always look as though they had not been long out of a bathtub. She had hazel eyes, a winsome smile, and hair like warm gold. Her figure was youthfully straight and supple--But that would not interest an engaged man. 

The D. C. glanced at her inquiringly. 

"Surely, surely," he muttered, "hum--hum!--" and tried to fix his mind on the letter. 

In fact, she was one of those girls who unintentionally and innocently render masculine minds uneasy through some delicate, indefinable attraction which defies analysis. 

"Surely," murmured the D. C., "surely! Hum--hum!" 

A subtle freshness like the breath of spring in a young orchard seemed to linger about her. She was exquisitely fashioned to trouble men, but she didn't wish to do such a-- 

Vaux, who was in love with another girl, took another uneasy look at her, sideways, then picked up his unlighted cigar and browsed upon it. 

"Yes," he said nervously, "this is one of those accursed code-ciphers. They always route them through to me. Why don't they notify the five--" 

"Are you going to turn THIS over to the Postal Inspection Service?" 

"What do you think about it, Miss Erith? You see it's one of those hopeless arbitrary ciphers for which there is no earthly solution except by discovering and securing the code book and working it out that way."7 

She said calmly, but with heightened colour: 

"A copy of that book is, presumably, in possession of the man to whom this letter is addressed." 

"Surely--surely. Hum--hum! What's his name, Miss Erith?"--glancing down at the yellow envelope. "Oh, yes--Herman Lauffer--hum!" 

He opened a big book containing the names of enemy aliens and perused it, frowning. The name of Herman Lauffer was not listed. He consulted other volumes containing supplementary lists of suspects and undesirables--lists furnished daily by certain services unnecessary to mention. 

"Here he is!" exclaimed Vaux; "--Herman Lauffer, picture-framer and gilder! That's his number on Madison Avenue!"--pointing to the type-written paragraph. "You see he's probably already under surveillance-one of the several services is doubtless keeping tabs on him. I think I'd better call up the--" 

"Please!--Mr. Vaux!" she pleaded. 

He had already touched the telephone receiver to unhook it. Miss Erith looked at him appealingly; her eyes were very, very hazel. 

"Couldn't we handle it?" she asked. 

"WE?" 

"You and I!" 

"But that's not our affair, Miss Erith--" 

"Make it so! Oh, please do. Won't you?" 

Vaux's arm fell to the desk top. He sat thinking for a few minutes. Then he picked up a pencil in an absent-minded manner and began to trace little circles, squares, and crosses on his pad, stringing them along line after line as though at hazard and apparently thinking of anything except what he was doing. 

The paper on which he seemed to be so idly employed lay on his desk directly under Miss Erith's eyes; and after a while the girl began to laugh softly to herself. 

"Thank you, Mr. Vaux," she said. "This is the opportunity I have longed for." 

Vaux looked up at her as though he did not understand. But the girl laid one finger on the lines of circles, squares, dashes and crosses, and, still laughing, read them off, translating what he had written: 

"You are a very clever girl. I've decided to turn this case over to you. After all, your business is to decipher cipher, and you can't do it without the book." 

They both laughed. 

"I don't see how you ever solved that," he said, delighted to tease her. 

"How insulting!--when you know it is one of the oldest and most familiar of codes--the 1-2-3 and _a-b-c_ combination!" 

"Rather rude of you to read it over my shoulder, Miss Erith. It isn't done--" 

"You meant to see if I could! You know you did!" 

"Did I?" 

"Of course! That old 'Seal of Solomon' cipher is perfectly transparent." 

"Really? But how about THIS!"--touching the sheets of the Lauffer letter--"how are you going to read this sequence of Arabic numerals?" 

"I haven't the slightest idea," said the girl, candidly. 

"But you request the job of trying to find the key?" he suggested ironically. 

"There is no key. You know it." 

"I mean the code book." 

"I would like to try to find it." 

"How are you going to go about it?" 

"I don't know yet." 

Vaux smiled. "All right; go ahead, my dear Miss Erith. You're officially detailed for this delightful job. Do it your own way, but do it--" 

"Thank you so much!" 

"--In twenty-four hours," he added grimly. "Otherwise I'll turn it over to the P.I." 

"Oh! That IS brutal of you!" 

"Sorry. But if you can't get the code-book in twenty-four hours I'll have to call in the Service that can." 

The girl bit her lip and held out her hand for the letter. 

"I can't let it go out of my office," he remarked. "You know that, Miss Erith." 

"I merely wish to copy it," she said reproachfully. Her eyes were hazel. 

"I ought not to let you take a copy out of this office," he muttered. 

"But you will, won't you?" 

"All right. Use that machine over there. Hum--hum!" 

For twenty minutes the girl was busy typing before the copy was finally ready. Then, comparing it and finding her copy accurate, she returned the original to Mr. Vaux, and rose with that disturbing grace peculiar to her every movement. 

"Where may I telephone you when you're not here?" she inquired diffidently, resting one slim, white hand on his desk. 

"At the Racquet Club. Are you going out?" 

"Yes." 

"What! You abandon me without my permission?" 

She nodded with one of those winsome smiles which incline young men to revery. Then she turned and walked toward the cloak room. 

The D. C. was deeply in love with somebody else, yet he found it hard to concentrate his mind for a while, and he chewed his unlighted cigar into a pulp. Alas! Men are that way. Not sometimes. Always. 

Finally he shoved aside the pile of letters which he had been trying to read, unhooked the telephone receiver, called a number, got it, and inquired for a gentleman named Cassidy. 

To the voice that answered he gave the name, business and address of Herman Lauffer, and added a request that undue liberties be taken with any out going letters mailed and presumably composed and written by Mr. Lauffer's own fair hand. 

"Much obliged, Mr. Vaux," cooed Cassidy, in a voice so suave that Vaux noticed its unusual blandness and asked if that particular Service already had "anything on Lauffer." 

"Not soon but yet!" replied Mr. Cassidy facetiously, "thanks ENTIRELY to your kind tip, Mr. Vaux." 

And Vaux, suspicious of such urbane pleasantries, rang off and resumed his mutilated cigar. 

"Now, what the devil does Cassidy know about Herman Lauffer," he mused, "and why the devil hasn't his Bureau informed us?" After long pondering he found no answer. Besides, he kept thinking at moments about Miss Erith, which confused him and diverted his mind from the business on hand. 

So, in his perplexity, he switched on the electric foot-warmer, spread his fur overcoat over his knees, uncorked a small bottle and swallowed a precautionary formaldehyde tablet, unlocked a drawer of his desk, fished out a photograph, and gazed intently upon it. 

It was the photograph of his Philadelphia affianced. Her first name was Arethusa. To him there was a nameless fragrance about her name. And sweetly, subtly, gradually the lovely phantasm of Miss Evelyn Erith faded, vanished into the thin and frigid atmosphere of his office. 

That was his antidote to Miss Erith--the intent inspection of his fiancee's very beautiful features as inadequately reproduced by an expensive and fashionable Philadelphia photographer. 

It did the business for Miss Erith every time. 

The evening was becoming one of the coldest ever recorded in New York. The thermometer had dropped to 8 degrees below zero and was still falling. Fifth Avenue glittered, sheathed in frost; traffic police on post stamped and swung their arms to keep from freezing; dry snow underfoot squeaked when trodden on; crossings were greasy with glare ice. 

It was, also, one of those meatless, wheatless, heatless nights when the privation which had hitherto amused New York suddenly became an ugly menace. There was no coal to be had and only green wood. The poor quietly died, as usual; the well-to-do ventured a hod and a stick or two in open grates, or sat huddled under rugs over oil or electric stoves; or migrated to comfortable hotels. And bachelors took to their clubs. That is where Clifford Vaux went from his chilly bachelor lodgings. He fled in a taxi, buried cheek-deep in his fur collar, hating all cold, all coal companies, and all Kaisers. 

In the Racquet Club he found many friends similarly self-dispossessed, similarly obsessed by discomfort and hatred. But there seemed to be some steam heat there, and several open fires; and when the wheatless, meatless meal was ended and the usual coteries drifted to their usual corners, Mr. Vaux found himself seated at a table with a glass of something or other at his elbow, which steamed slightly and had a long spoon in it; and he presently heard himself saying to three other gentlemen: "Four hearts." 

His voice sounded agreeably in his own ears; the gentle glow of a lignum-vitae wood fire smote his attenuated shins; he balanced his cards in one hand, a long cigar in the other, exhaled a satisfactory whiff of aromatic smoke, and smiled comfortably upon the table. 

"Four hearts," he repeated affably. "Does anybody--" 

The voice of Doom interrupted him: 

"Mr. Vaux, sir--" 

The young man turned in his easy-chair and beheld behind him a club servant, all over silver buttons. 

"The telephone, Mr. Vaux," continued that sepulchral voice. 

"All right," said the young man. "Bill, will you take my cards?"--he laid his hand, face down, rose and left the pleasant warmth of the card-room with a premonitory shiver. 

"Well?" he inquired, without cordiality, picking up the receiver. 

"Mr. Vaux?" came a distinct voice which he did not recognise. 

"Yes," he snapped, "who is it?" 

"Miss Erith." 

"Oh--er--surely--surely! GOOD-evening, Miss Erith!" 

"Good-evening, Mr. Vaux. Are you, by any happy chance, quite free this evening?" 

"Well--I'm rather busy--unless it is important--hum--hum!--in line of duty, you know--" 

"You may judge. I'm going to try to secure that code-book to-night." 

"Oh! Have you called in the--" 

"No!" 

"Haven't you communicated with--" 

"No!" 

"Why not?" 

"Because there's too much confusion already--too much petty jealousy and working at cross-purposes. I have been thinking over the entire problem. You yourself know how many people have escaped through jealous or over-zealous officers making premature arrests. We have six different secret-service agencies, each independent of the other and each responsible to its own independent chief, all operating for the Government in New York City. You know what these agencies are--the United States Secret Service, the Department of Justice Bureau of Investigation, the Army Intelligence Service, Naval Intelligence Service, Neutrality Squads of the Customs, and the Postal Inspection. Then there's the State Service and the police and several other services. And there is no proper co-ordination, no single head for all these agencies. The result is a ghastly confusion and shameful inefficiency. 

"This affair which I am investigating is a delicate one, as you know. Any blundering might lose us the key to what may be a very dangerous conspiracy. So I prefer to operate entirely within the jurisdiction of our own Service--" 

"What you propose to do is OUTSIDE of our province!" he interrupted. 

"I'm not so sure. Are you?" 

"Well--hum--hum!--what is it you propose to do to-night?" 

"I should like to consult my Chief of Division." 

"Meaning me?" 

"Of course." 

"When?" 

"Now!" 

"Where are you just now, Miss Erith?" 

"At home. Could you come to me?" 

Vaux shivered again. 

"Where d-do you live?" he asked, with chattering teeth. 

She gave him the number of a private house on 83d Street just off Madison Avenue. And as he listened he began to shiver all over in the anticipated service of his country. 

"Very well," he said, "I'll take a taxi. But this has Valley Forge stung to death, you know." 

She said: 

"I took the liberty of sending my car to the Racquet Club for you. It should be there now. There's a foot-warmer in it." 

"Thank you so much," he replied with a burst of shivers. "I'll b-b-be right up." 

As he left the telephone the doorman informed him that an automobile was waiting for him. 

So, swearing under his frosty breath, he went to the cloak-room, got into his fur coat, walked back to the card-room and gazed wrathfully upon the festivities. 

"What did my hand do, Bill?" he inquired glumly, when at last the scorer picked up his pad and the dealer politely shoved the pack toward his neighbour for cutting. 

"You ruined me with your four silly hearts," replied the man who had taken his cards. "Did you think you were playing coon-can?" 

"Sorry, Bill. Sit in for me, there's a good chap. I'm not likely to be back to-night--hang it!" 

Perfunctory regrets were offered by the others, already engrossed in their new hands; Vaux glanced unhappily at the tall, steaming glass, which had been untouched when he left, but which was now merely half full. Then, with another lingering look at the cheerful fire, he sighed, buttoned his fur coat, placed his hat firmly upon his carefully parted hair, and walked out to perish bravely for his native land. 

On the sidewalk a raccoon-furred chauffeur stepped up with all the abandon of a Kodiak bear: 

"Mr. Vaux, sir?" 

"Yes." 

"Miss Erith's car." 

"Thanks," grunted Vaux, climbing into the pretty coupe and cuddling his shanks under a big mink robe, where, presently, he discovered a foot-warmer, and embraced it vigorously between his patent-leather shoes. 

It had now become the coldest night on record in New York City. Fortunately he didn't know that; he merely sat there and hated Fate. 

Up the street and into Fifth Avenue glided the car and sped northward through the cold, silvery lustre of the arc-lights hanging like globes of moonlit ice from their frozen stalks of bronze. 

The noble avenue was almost deserted; nobody cared to face such terrible cold. Few motors were abroad, few omnibuses, and scarcely a wayfarer. Every sound rang metallic in the black and bitter air; the windows of the coupe clouded from his breath; the panels creaked. 

At the Plaza he peered fearfully out upon the deserted Circle, where the bronze lady of the fountain, who is supposed to represent Plenty, loomed high in the electric glow, with her magic basket piled high with icicles. 

"Yes, plenty of ice," sneered Vaux. "I wish she'd bring us a hod or two of coal." 

The wintry landscape of the Park discouraged him profoundly. 

"A man's an ass to linger anywhere north of the equator," he grumbled. "Dickybirds have more sense." And again he thought of the wood fire in the club and the partly empty but steaming glass, and the aroma it had wafted toward him; and the temperature it must have imparted to "Bill." 

He was immersed in arctic gloom when at length the car stopped. A butler admitted him to a brown-stone house, the steps of which had been thoughtfully strewn with furnace cinders. 

"Miss Erith?" 

"Yes, sir." 

"Announce Mr. Vaux, partly frozen." 

"The library, if you please, sir," murmured the butler, taking hat and coat. 

So Vaux went up stairs with the liveliness of a crippled spider, and Miss Erith came from a glowing fireside to welcome him, giving him a firm and slender hand. 

"You ARE cold," she said. "I'm so sorry to have disturbed you this evening." 

He said: 

"Hum--hum--very kind--m'sure--hum--hum!" 

There were two deep armchairs before the blaze; Miss Erith took one, Vaux collapsed upon the other. 

She was disturbingly pretty in her evening gown. There were cigarettes on a little table at his elbow, and he lighted one at her suggestion and puffed feebly. 

"Which?" she inquired smilingly. 

He understood: "Irish, please." 

"Hot?" 

"Thank you, yes," 

When the butler had brought it, the young man began to regret the Racquet Club less violently. 

"It's horribly cold out," he said. "There's scarcely a soul on the streets." 

She nodded brightly: 

"It's a wonderful night for what we have to do. And I don't mind the cold very much." 

"Are you proposing to go OUT?" he asked, alarmed. 

"Why, yes. You don't mind, do you?" 

"Am _I_ to go, too?" 

"Certainly. You gave me only twenty-four hours, and I can't do it alone in that time." 

He said nothing, but his thoughts concentrated upon a single unprintable word. 

"What have you done with the original Lauffer letter, Mr. Vaux?" she inquired rather nervously. 

"The usual. No invisible ink had been used; nothing microscopic. There was nothing on the letter or envelope, either, except what we saw." 

The girl nodded. On a large table behind her chair lay a portfolio. She turned, drew it toward her, and lifted it into her lap. 

"What have you discovered?" he inquired politely, basking in the grateful warmth of the fire. 

"Nothing. The cipher is, as I feared, purely arbitrary. It's exasperating, isn't it?" 

He nodded, toasting his shins. 

"You see," she continued, opening the portfolio, "here is my copy of this wretched cipher letter. I have transferred it to one sheet. It's nothing but a string of Arabic numbers interspersed with meaningless words. These numbers most probably represent, in the order in which they are written, first the number of the page of some book, then the line on which the word is to be found--say, the tenth line from the top, or maybe from the bottom--and then the position of the word--second from the left or perhaps from the right." 

"It's utterly impossible to solve that unless you have the book," he remarked; "therefore, why speculate, Miss Erith?" 

"I'm going to try to find the book." 

"How?" 

"By breaking into the shop of Herman Lauffer." 

"House-breaking? Robbery?" 

"Yes." 

Vaux smiled incredulously: 

"Granted that you get into Lauffer's shop without being arrested, what then?" 

"I shall have this cipher with me. There are not likely to be many books in the shop of a gilder and maker of picture frames. I shall, by referring to this letter, search what books I find there for a single coherent sentence. When I discover such a sentence I shall know that I have the right book." 

The young man smoked reflectively and gazed into the burning coals. 

"So you propose to break into his shop to-night and steal the book?" 

"There seems to be nothing else to do, Mr. Vaux." 

"Of course," he remarked sarcastically, "we could turn this matter over to the proper authorities--" 

"I WON'T! PLEASE don't!" 

"Why not?" 

"Because I have concluded that it IS part of our work. And I've begun already. I went to see Lauffer. I took a photograph to be framed." 

"What does he look like?" 

"A mink--an otter--one of those sharp-muzzled little animals!--Two tiny eyes, rather close together, a long nose that wrinkles when he talks, as though he were sniffing at you; a ragged, black moustache, like the furry muzzle-bristles of some wild thing--that is a sketch of Herman Lauffer." 

"A pretty man," commented Vaux, much amused. 

"He's little and fat of abdomen, but he looks powerful." 

"Prettier and prettier!" 

They both laughed. A pleasant steam arose from the tall glass at his elbow. 

"Well," she said, "I have to change my gown--" 

"Good Lord! Are we going now?" he remonstrated. 

"Yes. I don't believe there will be a soul on the streets." 

"But I don't wish to go at all," he explained. "I'm very happy here, discussing things." 

"I know it. But you wouldn't let me go all alone, would you, Mr. Vaux?" 

"I don't want you to go anywhere." 

"But I'm GOING!" 

"Here's where I perish," groaned Vaux, rising as the girl passed him with her pretty, humorous smile, moving lithely, swiftly as some graceful wild thing passing confidently through its own domain. 

Vaux gazed meditatively upon the coals, glass in one hand, cigarette in the other. Patriotism is a tough career. 

"This is worse than inhuman," he thought. "If I go out on such an errand to-night I sure am doing my bitter bit. ... Probably some policeman will shoot me--unless I freeze to death. This is a vastly unpleasant affair.... Vastly!" 

He was still caressing the fire with his regard when Miss Erith came back. 

She wore a fur coat buttoned to the throat, a fur toque, fur gloves. As he rose she naively displayed a jimmy and two flashlights. 

"I see," he said, "very nice, very handy! But we don't need these to convict us." 

She laughed and handed him the instruments; and he pocketed them and followed her downstairs. 

Her car was waiting, engine running; she spoke to the Kadiak chauffeur, got in, and Vaux followed. 

"You know," he said, pulling the mink robe over her and himself, "you're behaving very badly to your superior officer." 

"I'm so excited, so interested! I hope I'm not lacking in deference to my honoured Chief of Division. Am I, Mr. Vaux?" 

"You certainly hustle me around some! This is a crazy thing we're doing." 

"Oh, I'm sorry!" 

"You're an autocrat. You're a lady-Nero! Tell me, Miss Erith, were you ever afraid of anything on earth?" 

"Yes." 

"What?" 

"Lightning and caterpillars." 

"Those are probably the only really dangerous things I never feared," he said. "You seem to be young and human and feminine. Are you?" 

"Oh, very." 

"Then why aren't you afraid of being shot for a burglar, and why do you go so gaily about grand larceny?" 

The girl's light laughter was friendly and fearless. 

"Do you live alone?" he inquired after a moment's silence. 

"Yes. My parents are not living." 

"You are rather an unusual girl, Miss Erith." 

"Why?" 

"Well, girls of your sort are seldom as much in earnest about their war work as you seem to be," he remarked with gentle irony. 

"How about the nurses and drivers in France?" 

"Oh, of course. I mean nice girls, like yourself, who do near-war work here in New York--" 

"You ARE brutal!" she exclaimed. "I am mad to go to France! It is a sacrifice--a renunciation for me to remain in New York. I understand nursing and I know how to drive a car; but I have stayed here because my knowledge of ciphers seemed to fit me for this work." 

"I was teasing you," he said gently. 

"I know it. But there is SO much truth in what you say about near-war work. I hate that sort of woman.... Why do you laugh?" 

"Because you're just a child. But you are full of ability and possibility, Miss Erith." 

"I wish my ability might land me in France!" 

"Surely, surely," he murmured. 

"Do you think it will, Mr. Vaux?" 

"Maybe it will," he said, not believing it. He added: "I think, however, your undoubted ability is going to land us both in jail." 

At which pessimistic prognosis they both began to laugh. She was very lovely when she laughed. 

"I hope they'll give us the same cell," she said. "Don't you?" 

"Surely," he replied gaily. 

Once he remembered the photograph of Arethusa in his desk at headquarters, and thought that perhaps he might need it before the evening was over. 

"Surely, surely," he muttered to himself, "hum--hum!" 

Her coupe stopped in Fifty-sixth Street near Madison Avenue. 

"The car will wait here," remarked the girl, as Vaux helped her to descend. "Lauffer's shop is just around the corner." She took his arm to steady herself on the icy sidewalk. He liked it. 

In the bitter darkness there was not a soul to be seen on the street; no tramcars were approaching on Madison Avenue, although far up on the crest of Lenox Hill the receding lights of one were just vanishing. 

"Do you see any policemen?" she asked in a low voice. 

"Not one. They're all frozen to death, I suppose, as we will be in a few minutes." 

They turned into Madison Avenue past the Hotel Essex. There was not a soul to be seen. Even the silver-laced porter had retired from the freezing vestibule. A few moments later Miss Erith paused before a shop on the ground floor of an old-fashioned brownstone residence which had been altered for business. 

Over the shop-window was a sign: "H. Lauffer, Frames and Gilding." The curtains of the shop-windows were lowered. No light burned inside. 

Over Lauffer's shop was the empty show-window of another shop--on the second floor--the sort of place that milliners and tea-shop keepers delight in--but inside the blank show-window was pasted the sign "To Let." 

Above this shop were three floors, evidently apartments. The windows were not lighted. 

"Lauffer lives on the fourth floor," said Miss Erith. "Will you please give me the jimmy, Vaux?" 

He fished it out of his overcoat pocket and looked uneasily up and down the deserted avenue while the girl stepped calmly into the open entryway. There were two doors, a glass one opening on the stairs leading to the upper floors, and the shop door on the left. 

She stooped over for a rapid survey, then with incredible swiftness jimmied the shop door. 

The noise of the illegal operations awoke the icy and silent avenue with a loud, splitting crash! The door swung gently inward. 

"Quick!" she said. And he followed her guiltily inside. 

The shop was quite warm. A stove in the rear room still emitted heat and a dull red light. On the stove was a pot of glue, or some other substance used by gilders and frame makers. Steam curled languidly from it; also a smell not quite as languid. 

Vaux handed her an electric torch, then flashed his own. The next moment she found a push button and switched on the lights in the shop. Then they extinguished their torches. 

Stacks of frames in raw wood, frames in "compo," samples gilded and in natural finish littered the untidy place. A few process "mezzotints" hung on the walls. There was a counter on which lay twine, shears and wrapping paper, and a copy of the most recent telephone directory. It was the only book in sight, and Miss Erith opened it and spread her copy of the cipher-letter beside it. Then she began to turn the pages according to the numbers written in her copy of the cipher letter. 

Meanwhile, Vaux was prowling. There were no books in the rear room; of this he was presently assured. He came back into the front shop and began to rummage. A few trade catalogues rewarded him and he solemnly laid them on the counter. 

"The telephone directory is NOT the key," said Miss Erith, pushing it aside. A few moments were sufficient to convince them that the key did not lie within any of the trade catalogues either. 

"Have you searched very carefully?" she asked. 

"There's not another book in the bally shop." 

"Well, then, Lauffer must have it in his apartment upstairs." 

"Which apartment is it?" 

"The fourth floor. His name is under a bell on a brass plate in the entry. I noticed it when I came in." She turned off the electric light; they went to the door, reconnoitred cautiously, saw nobody on the avenue. However, a tramcar was passing, and they waited; then Vaux flashed his torch on the bell-plate. 

Under the bell marked "Fourth Floor" was engraved Herman Lauffer's name. 

"You know," remonstrated Vaux, "we have no warrant for this sort of thing, and it means serious trouble if we're caught." 

"I know it. But what other way is there?" she inquired naively. "You allowed me only twenty-four hours, and I WON'T back out!" 

"What procedure do you propose now?" he asked, grimly amused, and beginning to feel rather reckless himself, and enjoying the feeling. "What do you wish to do?" he repeated. "I'm game." 

"I have an automatic pistol," she remarked seriously, tapping her fur-coat pocket, "--and a pair of handcuffs--the sort that open and lock when you strike a man on the wrist with them. You know the kind?" 

"Surely. You mean to commit assault and robbery in the first degree upon the body of the aforesaid Herman?" 

"I-is that it?" she faltered. 

"It is." 

She hesitated: 

"That is rather dreadful, isn't it?" 

"Somewhat. It involves almost anything short of life imprisonment. But _I_ don't mind." 

"We couldn't get a search-warrant, could we?" 

"We have found nothing, so far, in that cipher letter to encourage us in applying for any such warrant," he said cruelly. 

"Wouldn't the excuse that Lauffer is an enemy alien and not registered aid us in securing a warrant?" she insisted. 

"He is not an alien. I investigated that after you left this afternoon. His parents were German but he was born in Chicago. However, he is a Hun, all right--I don't doubt that.... What do you propose to do now?" 

She looked at him appealingly: 

"Won't you allow me more than twenty-four hours?" 

"I'm sorry." 

"Why won't you?" 

"Because I can't dawdle over this affair." 

The girl smiled at him in her attractive, resolute way: 

"Unless we find that book we can't decipher this letter. The letter comes from Mexico,--from that German-infested Republic. It is written to a man of German parentage and it is written in cipher. The names of Luxburg, Caillaux, Bolo, Bernstorff are still fresh in our minds. Every day brings us word of some new attempt at sabotage in the United States. Isn't there ANY way, Mr. Vaux, for us to secure the key to this cipher letter?" 

"Not unless we go up and knock this man Lauffer on the head. Do you want to try it?" 

"Couldn't we knock rather gently on his head?" 

Vaux stifled a laugh. The girl was so pretty, the risk so tremendous, the entire proceeding so utterly outrageous that a delightful sense of exhilaration possessed him. 

"Where's that gun?" he said. 

She drew it out and handed it to him. 

"Is it loaded?" 

"Yes." 

"Where are the handcuffs?" 

She fished out the nickel-plated bracelets and he pocketed his torch. A pleasant thrill passed through the rather ethereal anatomy of Mr. Vaux. 

"All right," he said briskly. "Here's hoping for adjoining cells!" 

To jimmy the glass door was the swiftly cautious work of a moment or two. Then the dark stairs rose in front of them and Vaux took the lead. It was as cold as the pole in there, but Vaux's blood was racing now. And alas! the photograph of Arethusa was in his desk at the office! 

On the third floor he flashed his torch through an empty corridor and played it smartly over every closed door. On the fourth floor he took his torch in his left hand, his pistol in his right. 

"The door to the apartment is open!" she whispered. 

It was. A lamp on a table inside was still burning. They had a glimpse of a cheap carpet on the floor, cheap and gaudy furniture. Vaux extinguished and pocketed his torch, then, pistol lifted, he stepped noiselessly into the front room. 

It seemed to be a sort of sitting-room, and was in disorder; cushions from a lounge lay about the floor; several books were scattered near them; an upholstered chair had been ripped open and disembowelled, and its excelsior stuffing strewn broadcast. 

"This place looks as though it had been robbed!" whispered Vaux. "What the deuce do you suppose has happened?" 

They moved cautiously to the connecting-door of the room in the rear. The lamplight partly illuminated it, revealing it as a bedroom. 

Bedclothes trailed to the floor, which also was littered with dingy masculine apparel flung about at random. Pockets of trousers and of coats had been turned inside out, in what apparently had been a hasty and frantic search. 

The remainder of the room was in disorder, too; underwear had been pulled from dresser and bureau; the built-in wardrobe doors swung ajar and the clothing lay scattered about, every pocket turned inside out. 

"For heaven's sake," muttered Vaux, "what do you suppose this means?" 

"Look!" she whispered, clutching his arm and pointing to the fireplace at their feet. 

On the white-tiled hearth in front of the unlighted gas-logs lay the stump of a cigar. 

From it curled a thin thread of smoke. 

They stared at the smoking stub on the hearth, gazed fearfully around the dimly lighted bedroom, and peered into the dark dining-room beyond. 

Suddenly Miss Erith's hand tightened on his sleeve. 

"Hark!" she motioned. 

He heard it, too--a scuffling noise of heavy feet behind a closed door somewhere beyond the darkened dining-room. 

"There's somebody in the kitchenette!" she whispered. 

Vaux produced his pistol; they stole forward into the dining-room; halted by the table. 

"Flash that door," he said in a low voice. 

Her electric torch played over the closed kitchen door for an instant, then, at a whispered word from him, she shut it off and the dining-room was plunged again into darkness. 

And then, before Vaux or Miss Erith had concluded what next was to be done, the kitchen door opened; and, against the dangling lighted bulb within, loomed a burly figure wearing hat and overcoat and a big bass voice rumbled through the apartment: 

"All right, all right, keep your shirt on and I'll get your coat and vest for you--" 

Then Miss Erith flashed her torch full in the man's face, blinding him. And Vaux covered him with levelled pistol. 

Even then the man made a swift motion toward his pocket, but at Vaux's briskly cheerful warning he checked himself and sullenly and very slowly raised both empty hands. 

"All right, all right," he grumbled. "It's on me this time. Go on; what's the idea?" 

"W-well, upon my word!" stammered Vaux, "it's Cassidy!" 

"F'r the love o' God," growled Cassidy, "is that YOU, Mr. Vaux!" He lowered his arms sheepishly, reached out and switched on the ceiling light over the dining-room table. "Well, f'r--" he began; and, seeing Miss Erith, subsided. 

"What are you doing here?" demanded Vaux, disgusted with this glaring example of interference from another service. 

"What am I doing?" repeated Cassidy with a sarcastic glance at Miss Erith. "Faith, I'm pinching a German gentleman we've been watching these three months and more. Is that what you're up to, too?" 

"Herman Lauffer?" 

"That's the lad, sir. He's in the kitchen yonder, dressing f'r to take a little walk. I gotta get his coat and vest. And what are you doing here, sir?" 

"How did YOU get in?" asked Miss Erith, flushed with chagrin and disappointment. 

"With keys, ma'am." 

"Oh, Lord!" said Vaux, "we jimmied the door. What do you think of that, Cassidy?" 

"Did you so?" grinned Cassidy, now secure in his triumphant priority and inclined to become friendly. 

"I never dreamed that your division was watching Lauffer," continued Vaux, still red with vexation. "It's a wonder we didn't spoil the whole affair between us." 

"It is that!" agreed Cassidy with a wider grin. "And you can take it from me, Mr. Vaux, we never knew that the Postal Inspection was on to this fellow at all at all until you called me to stop outgoing letters." 

"What have you on him?" inquired Vaux. 

Cassidy laughed: 

"Oh, listen then! Would you believe this fellow was tryin' the old diagonal trick? Sure it was easy; I saw him mail a letter this afternoon and I got it. I'd been waiting three months for him to do something like that. But he's a fox--he is that, Mr. Vaux! Do you want to see the letter? I have it on me--" 

He fished it out of his inside pocket and spread it on the dining table under the light. 

"You know the game," he remarked, laying a thick forefinger on the diagonal line bisecting the page. "All I had to do was to test the letter by drawing that line across it from corner to corner. Read the words that the line cuts through. Can you beat it?" 

Vaux and Miss Erith bent over the letter, read the apparently innocent message it contained, then read the words through which the diagonal line had been drawn. 

Then Cassidy triumphantly read aloud the secret and treacherous information which the letter contained: 

"SEVEN UNITED STATES TRANSPORTS TO-DAY NEW YORK (BY THE) NORTHERN ROUTE. INFORM OUR U-BOATS. URGENCY REQUIRES INSTANT MEASURES. TEN MORE ARE TO SAIL FROM HERE NEXT WEEK." 

"The dirty Boche!" added Cassidy. "Dugan has left for Mexico to look up this brother of his and I'm lookin' up this snake, so I guess there's no harm done so far." 

"New York. 

"January 3rd. 1916. 

"My dear Brother: 

"For seven long weeks I have awaited a letter from you. The United-States mails from Mexico seem to be interrupted. Imagine my transports of joy when at last I hear from you today. You and I, dear brother, are the only ones left of our family--you in Vera Cruz. I in New-York--you in a hot Southern climate, I in a Northern, amid snow and ice, where the tardy sun does not route me from my bed till late in the morning. 

"However, I inform you with pleasure that I am well. I rejoice that our good health is mutual. After all, the dear old U. S. suits me. Of course railroads or boats could carry me to a warm climate, in case urgency required it. But I am quite well now, and my health requires merely prudence. However, if I am again ill at any instant, I shall leave for Florida, where all tho proper measures can be taken to combat my rheumatism, 

"Ten days ago I was in bed, and unable to do more than move my left arm. But th« doctors are confident that my malady is not going to return. If it does threaten to return I shall sail for Jacksonville at once, and from there go to Miami, and not return here until the warm and balmy weather of next spring has lasted at least a week. Affectionataly your brother. 

"Herman." 

He pocketed the letter and went into the bedroom to get a coat and vest for the prisoner. Miss Erith looked at Vaux. 

"Cassidy seems to know nothing about the code-cipher," she whispered. "I think he rummaged on general principles, not in search of any code-book." 

She looked around the dining-room. The doors of the yellow oak sideboard were open, but no book was there among the plated knives and forks and the cheap dishes. 

Cassidy came back with the garments he had been looking for--an overcoat, coat and vest--and he carried them into the kitchenette, whither presently Vaux followed him. 

Cassidy had just unlocked the handcuffs from the powerful wrists of a dark, stocky, sullen man who stood in his shirt-sleeves near a small deal table. 

"Lauffer?" inquired Vaux, dryly. 

"It sure is, ain't it, Herman?" replied Cassidy facetiously. "Now, then, me Dutch bucko, climb into your jeans, if YOU please--there's a good little Boche!" 

Vaux gazed curiously at the spy, who returned his inspection coolly enough while he wrinkled his nose at him, and his beady eyes roamed over him. 

When the prisoner had buttoned his vest and coat, Cassidy snapped on the bracelets again, whistling cheerily under his breath. 

As they started to leave the kitchenette, Vaux, who brought up the rear, caught sight of a large, thick book lying on the pantry shelf. It was labelled "Perfect Cook-Book," but he picked it up, shoved it into his overcoat pocket en passant, and followed Cassidy and his prisoner into the dining-room. 

Here Cassidy turned humorously to him and to Miss Erith. 

"I've cleaned up the place," he remarked, "but you're welcome to stay here and rummage if you want to. I'm sending one of our men back to take possession as soon as I lock up this bird." 

"All right. Good luck," nodded Vaux. 

Cassidy tipped his derby to Miss Erith, bestowed a friendly grin on Vaux. 

"Come along, old sport!" he said genially to Lauffer; and he walked away with his handcuffed prisoner, whistling "Garryowen." 

"Wait!" motioned Vaux to Miss Erith. He went to the stairs, listened to the progress of agent and prey, heard the street-door clash, then hastened back to the lighted dining-room, pulling the "Perfect Cook-Book" from his pocket. 

"I found that in the kitchenette," he remarked, laying it before her on the table. "Maybe that's the key?" 

"A cook-book!" She smiled, opened it. "Why--why, it's a DICTIONARY!" she exclaimed excitedly. 

"A dictionary!" 

"Yes! Look! Stormonth's English Dictionary!" 

"By ginger!" he said. "I believe it's the code-book! Where is your cipher letter, Miss Erith!" 

The girl produced it with hands that trembled a trifle, spread it out under the light. Then she drew from her pocket a little pad and a pencil. 

"Quick," she said, "look for page 17!" 

"Yes, I have it!" 

"First column!" 

"Yes." 

"Now try the twentieth word from the top!" 

He counted downward very carefully. 

"It is the word 'anagraph,'" he said; and she wrote it down. 

"Also, we had better try the twentieth word counting from the bottom of the page up," she said. "It might possibly be that." 

"The twentieth word, counting from the bottom of the column upward, is the word 'an,'" he said. She wrote it. 

"Now," she continued, "try page 15, second column, third word from TOP!" 

"'Ambrosia' is the word." 

"Try the third word from the BOTTOM." 

"'American.'" 

She pointed to the four words which she had written. Counting from the TOP of the page downward the first two words were "Anagraph ambrosia." But counting from the BOTTOM upward the two words formed the phrase: "AN AMERICAN." 

"Try page 730, first column, seventh word from the bottom," she said, controlling her excitement with an effort. 

"The word is 'who.'" 

"Page 212, second column, first word!" 

"'For.'" 

"Page 507, first column, seventh word!" 

"'Reasons.'" 

"We have the key!" she exclaimed. "Look at what I've written!--'An American who for reasons!' And here, in the cipher letter, it goes on--'of the most'--Do you see?" 

"It certainly looks like the key," he said. "But we'd better try another word or two." 

"Try page 717, first column, ninth word." 

"The word is 'vital.'" 

"Page 274, second column, second word." 

"'Importance!'" 

"It is the key! Here is what I have written: 'An American who for reasons, of the most vital importance!' Quick. We don't want a Secret Service man to find us here, Mr. Vaux! He'd object to our removing this book from Lauffer's apartment. Put it into your pocket and run!" And the pretty Miss Erith turned and took to her heels with Vaux after her. 

Through the disordered apartment and down the stairs they sped, out into the icy darkness and around the corner, where her car stood, engine running, and a blanket over the hood. 

As soon as the chauffeur espied them he whisked off the blanket; Miss Erith said: "Home!" and jumped in, and Vaux followed. 

Deep under the fur robe they burrowed, shivering more from sheer excitement than from cold, and the car flew across to Fifth Avenue and then northward along deserted sidewalks and a wintry park, where naked trees and shrubs stood stark as iron in the lustre of the white electric lamps. 

"That time the Secret Service made a mess of it," he said with a nervous laugh. "Did you notice Cassidy's grin of triumph?" 

"Poor Cassidy," she said. 

"I don't know. He butted in." 

"All the services are working at cross-purposes. It's a pity." 

"Well, Cassidy got his man. That's practically all he came for. Evidently he never heard of a code-book in connection with Lauffer's activities. That diagonal cipher caught him." 

"What luck," she murmured, "that you noticed that cook-book in the pantry! And what common sense you displayed in smuggling it!" 

"I didn't suppose it was THE book; I just took a chance." 

"To take a chance is the best way to make good, isn't it?" she said, laughing. "Oh, I am so thrilled, Mr. Vaux! I shall sit up all night over my darling cipher and my fascinating code-book-dictionary." 

"Will you be down in the morning?" he inquired. 

"Of course. Then to-morrow evening, if you will come to my house, I shall expect to show you the entire letter neatly deciphered." 

"Fine!" he exclaimed as the car stopped before her door. 

She insisted on sending him home in her car, and he was very grateful; so when he had seen her safely inside her house with the cook-book-dictionary clasped in her arms and a most enchanting smile on her pretty face, he made his adieux, descended the steps, and her car whirled him swiftly homeward
through the arctic night. 

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