The man in the corner pushed aside his glass, and leant across the table.

"Mysteries!" he commented. "There is no such thing as a mystery in connection with any crime, provided intelligence is brought to bear upon its investigation."

Very much astonished Polly Burton looked over the top of her newspaper, and fixed a pair of very severe, coldly inquiring brown eyes upon him.

She had disapproved of the man from the instant when he shuffled across the shop and sat down opposite to her, at the same marble-topped table which already held her large coffee (3d.), her roll and butter (2d.), and plate of tongue (6d.).

Now this particular corner, this very same table, that special view of the magnificent marble hall — known as the Norfolk Street branch of the Aërated Bread Company's depôts — were Polly's own corner, table, and view. Here she had partaken of eleven pennyworth of luncheon and one pennyworth of daily information ever since that glorious never-to-be-forgotten day when she was enrolled on the staff of the Evening Observer (we'll call it that, if you please), and became a member of that illustrious and world-famed organization known as the British Press.

She was a personality, was Miss Burton of the Evening Observer. Her cards were printed thus:

She had interviewed Miss Ellen Terry and the Bishop of Madagascar, Mr. Seymour Hicks and the Chief Commissioner of Police. She had been present at the last Marlborough House garden party — in the cloak-room, that is to say, where she caught sight of Lady Thingummy's hat, Miss What-you-may-call's sunshade, and of various other things modistical or fashionable, all of which were duly described under the heading "Royalty and Dress" in the early afternoon edition of the Evening Observer.

(The article itself is signed M.J.B., and is to be found in the files of that leading halfpennyworth.)

For these reasons — and for various others, too — Polly felt irate with the man in the corner, and told him so with her eyes, as plainly as any pair of brown eyes can speak.

She had been reading an article in the Daily Telegraph. The article was palpitatingly interesting. Had Polly been commenting audibly upon it? Certain it is that the man over there had spoken in direct answer to her thoughts.

She looked at him and frowned; the next moment she smiled. Miss Burton (of the Evening Observer) had a keen sense of humour, which two years' association with the British Press had not succeeded in destroying, and the appearance of the man was sufficient to tickle the most ultra-morose fancy. Polly thought to herself that she had never seen any one so pale, so thin, with such funny light-coloured hair, brushed very smoothly across the top of a very obviously bald crown. He looked so timid and nervous as he fidgeted incessantly with a piece of string; his long, lean, and trembling fingers tying and untying it into knots of wonderful and complicated proportions.

Having carefully studied every detail of the quaint personality Polly felt more amiable.

"And yet," she remarked kindly but authoritatively, "this article, in an otherwise well-informed journal, will tell you that, even within the last year, no fewer than six crimes have completely baffled the police, and the perpetrators of them are still at large."

"Pardon me," he said gently, "I never for a moment ventured to suggest that there were no mysteries to the police; I merely remarked that there were none where intelligence was brought to bear upon the investigation of crime."

"Not even in the Fenchurch Street mystery. I suppose," she asked sarcastically.

"Least of all in the so-called Fenchurch Street mystery," he replied quietly.

Now the Fenchurch Street mystery, as that extraordinary crime had popularly been called, had puzzled — as Polly well knew — the brains of every thinking man and woman for the last twelve months. It had puzzled her not inconsiderably; she had been interested, fascinated; she had studied the case, formed her own theories, thought about it all often and often, had even written one or two letters to the Press on the subject — suggesting, arguing, hinting at possibilities and probabilities, adducing proofs which other amateur detectives were equally ready to refute. The attitude of that timid man in the corner, therefore, was peculiarly exasperating, and she retorted with sarcasm destined to completely annihilate her self-complacent interlocutor.

"What a pity it is, in that case, that you do not offer your priceless services to our misguided though well-meaning police."

"Isn't it?" he replied with perfect good-humour. "Well, you know, for one thing I doubt if they would accept them; and in the second place my inclinations and my duty would — were I to become an active member of the detective force — nearly always be in direct conflict. As often as not my sympathies go to the criminal who is clever and astute enough to lead our entire police force by the nose.

"I don't know how much of the case you remember," he went on quietly. "It certainly, at first, began even to puzzle me. On the 12th of last December a woman, poorly dressed, but with an unmistakable air of having seen better days, gave information at Scotland Yard of the disappearance of her husband, William Kershaw, of no occupation, and apparently of no fixed abode. She was accompanied by a friend — a fat, oily-looking German — and between them they told a tale which set the police immediately on the move.

"It appears that on the 10th of December, at about three o'clock in the afternoon, Karl Müller, the German, called on his friend, William Kershaw, for the purpose of collecting a small debt — some ten pounds or so — which the latter owed him. On arriving at the squalid lodging in Charlotte Street, Fitzroy Square, he found William Kershaw in a wild state of excitement, and his wife in tears. Müller attempted to state the object of his visit, but Kershaw, with wild gestures, waved him aside, and — in his own words — flabbergasted him by asking him point-blank for another loan of two pounds, which sum, he declared, would be the means of a speedy fortune for himself and the friend who would help him in his need.

"After a quarter of an hour spent in obscure hints, Kershaw, finding the cautious German obdurate, decided to let him into the secret plan, which, he averred, would place thousands into their hands."

Instinctively Polly had put down her paper; the mild stranger, with his nervous air and timid, watery eyes, had a peculiar way of telling his tale, which somehow fascinated her.

"I don't know," he resumed, "if you remember the story which the German told to the police, and which was corroborated in every detail by the wife or widow. Briefly it was this: Some thirty years previously, Kershaw, then twenty years of age, and a medical student at one of the London hospitals, had a chum named Barker, with whom he roomed, together with another.

"The latter, so it appears, brought home one evening a very considerable sum of money, which he had won on the turf, and the following morning he was found murdered in his bed. Kershaw, fortunately for himself, was able to prove a conclusive alibi; he had spent the night on duty at the hospital; as for Barker, he had disappeared, that is to say, as far as the police were concerned, but not as far as the watchful eyes of his friend Kershaw were able to spy — at least, so the latter said. Barker very cleverly contrived to get away out of the country, and, after sundry vicissitudes, finally settled down at Vladivostok, in Eastern Siberia, where, under the assumed name of Smethurst, he built up an enormous fortune by trading in furs.

"Now, mind you, every one knows Smethurst, the Siberian millionaire. Kershaw's story that he had once been called Barker, and had committed a murder thirty years ago, was never proved, was it? I am merely telling you what Kershaw said to his friend the German and to his wife on that memorable afternoon of December the 10th.

"According to him Smethurst had made one gigantic mistake in his clever career — he had on four occasions written to his late friend, William Kershaw. Two of these letters had no bearing on the case, since they were written more than twenty-five years ago, and Kershaw, moreover, had lost them — so he said — long ago. According to him, however, the first of these letters was written when Smethurst, alias Barker, had spent all the money he had obtained from the crime, and found himself destitute in New York.

"Kershaw, then in fairly prosperous circumstances, sent him a £10 note for the sake of old times. The second, when the tables had turned, and Kershaw had begun to go downhill, Smethurst, as he then already called himself, sent his whilom friend £50. After that, as Müller gathered, Kershaw had made sundry demands on Smethurst's ever-increasing purse, and had accompanied these demands by various threats, which, considering the distant country in which the millionaire lived, were worse than futile.

"But now the climax had come, and Kershaw, after a final moment of hesitation, handed over to his German friend the two last letters purporting to have been written by Smethurst, and which, if you remember, played such an important part in the mysterious story of this extraordinary crime. I have a copy of both these letters here," added the man in the corner, as he took out a piece of paper from a very worn-out pocket-book, and, unfolding it very deliberately, he began to read: —

"'Sir, — Your preposterous demands for money are wholly unwarrantable. I have already helped you quite as much as you deserve. However, for the sake of old times, and because you once helped me when I was in a terrible difficulty, I am willing to once more let you impose upon my good nature. A friend of mine here, a Russian merchant, to whom I have sold my business, starts in a few days for an extended tour to many European and Asiatic ports in his yacht, and has invited me to accompany him as far as England. Being tired of foreign parts, and desirous of seeing the old country once again after thirty years' absence, I have decided to accept his invitation. I don't know when we may actually be in Europe, but I promise you that as soon as we touch a suitable port I will write to you again, making an appointment for you to see me in London. But remember that if your demands are too preposterous I will not for a moment listen to them, and that I am the last man in the world to submit to persistent and unwarrantable blackmail.

"The second letter was dated from Southampton," continued the old man in the corner calmly, "and, curiously enough, was the only letter which Kershaw professed to have received from Smethurst of which he had kept the envelope, and which was dated. It was quite brief," he added, referring once more to his piece of paper.

"'Dear Sir, — Referring to my letter of a few weeks ago, I wish to inform you that the Tsarskoe Selo will touch at Tilbury on Tuesday next, the 10th. I shall land there, and immediately go up to London by the first train I can get. If you like, you may meet me at Fenchurch Street Station, in the first-class waiting-room, in the late afternoon. Since I surmise that after thirty years' absence my face may not be familiar to you, I may as well tell you that you will recognize me by a heavy Astrakhan fur coat, which I shall wear, together with a cap of the same. You may then introduce yourself to me, and I will personally listen to what you may have to say.

"It was this last letter which had caused William Kershaw's excitement and his wife's tears. In the German's own words, he was walking up and down the room like a wild beast, gesticulating wildly, and muttering sundry exclamations. Mrs. Kershaw, however, was full of apprehension. She mistrusted the man from foreign parts — who, according to her husband's story, had already one crime upon his conscience — who might, she feared, risk another, in order to be rid of a dangerous enemy. Woman-like, she thought the scheme a dishonourable one, for the law, she knew, is severe on the blackmailer.

"The assignation might be a cunning trap, in any case it was a curious one; why, she argued, did not Smethurst elect to see Kershaw at his hotel the following day? A thousand whys and wherefores made her anxious, but the fat German had been won over by Kershaw's visions of untold gold, held tantalisingly before his eyes. He had lent the necessary £2, with which his friend intended to tidy himself up a bit before he went to meet his friend the millionaire. Half an hour afterwards Kershaw had left his lodgings, and that was the last the unfortunate woman saw of her husband, or Müller, the German, of his friend.

"Anxiously his wife waited that night, but he did not return; the next day she seems to have spent in making purposeless and futile inquiries about the neighbourhood of Fenchurch Street; and on the 12th she went to Scotland Yard, gave what particulars she knew, and placed in the hands of the police the two letters written by Smethurst."