"Now I must tell you," continued the man in the corner, "that after I had read the account of the double robbery, which appeared in the early afternoon papers, I set to work and had a good think — yes!" he added with a smile, noting Polly's look at the bit of string, on which he was still at work, "yes! aided by this small adjunct to continued thought — I made notes as to how I should proceed to discover the clever thief, who had carried off a small fortune in a single night. Of course, my methods are not those of a London detective; he has his own way of going to work. The one who was conducting this case questioned the unfortunate jeweller very closely about his servants and his household generally.

"'I have three servants,' explained Mr. Shipman, two of whom have been with me for many years; one, the housemaid, is a fairly new comer — she has been here about six months. She came recommended by a friend, and bore an excellent character. She and the parlourmaid room together. The cook, who knew me when I was a schoolboy, sleeps alone; all three servants sleep on the floor above. I locked the jewels up in the safe which stands in the dressing-room. My keys and watch I placed, as usual, beside my bed. As a rule, I am a fairly light sleeper.

"'I cannot understand how it could have happened — but — you had better come up and have a look at the safe. The key must have been abstracted from my bedside, the safe opened, and the keys replaced — all while I was fast asleep. Though I had no occasion to look into the safe until just now, I should have discovered my loss before going to business, for I intended to take the diamonds away with me — '

"The detective and the inspector went up to have a look at the safe. The lock had in no way been tampered with — it had been opened with its own key. The detective spoke of chloroform, but Mr. Shipman declared that when he woke in the morning at about half-past seven there was no smell of chloroform in the room. However, the proceedings of the daring thief certainly pointed to the use of an anaesthetic. An examination of the premises brought to light the fact that the burglar had, as in Mr. Knopf's house, used the glass-panelled door from the garden as a means of entrance, but in this instance he had carefully cut out the pane of glass with a diamond, slipped the bolts, turned the key, and walked in.

"'Which among your servants knew that you had the diamonds in your house last night, Mr. Shipman?' asked the detective.

"'Not one, I should say,' replied the jeweller, 'though, perhaps, the parlourmaid, whilst waiting at table, may have heard me and Mr. Knopf discussing our bargain.'

"'Would you object to my searching all your servants' boxes?'

"'Certainly not. They would not object, either, I am sure. They are perfectly honest.'

"The searching of servants' belongings is invariably a useless proceeding," added the man in the corner, with a shrug of the shoulders. "No one, not even a latter-day domestic, would be fool enough to keep stolen property in the house. However, the usual farce was gone through, with more or less protest on the part of Mr. Shipman's servants, and with the usual result.

"The jeweller could give no further information; the detective and inspector, to do them justice, did their work of investigation minutely and, what is more, intelligently. It seemed evident, from their deductions, that the burglar had commenced proceedings on No. 26, Phillimore Terrace, and had then gone on, probably climbing over the garden walls between the houses to No. 22, where he was almost caught in the act by Robertson. The facts were simple enough, but the mystery remained as to the individual who had managed to glean the information of the presence of the diamonds in both the houses, and the means which he had adopted to get that information. It was obvious that the thief or thieves knew more about Mr. Knopf's affairs than Mr. Shipman's, since they had known how to use Mr. Emile Knopf's name in order to get his brother out of the way.

"It was now nearly ten o'clock, and the detectives, having taken leave of Mr. Shipman, went back to No. 22, in order to ascertain whether Mr. Knopf had come back; the door was opened by the old charwoman, who said that her master had returned, and was having some breakfast in the dining-room.

"Mr. Ferdinand Knopf was a middle-aged man, with sallow complexion, black hair and beard, of obviously Hebrew extraction. He spoke with a marked foreign accent, but very courteously, to the two officials, who, he begged, would excuse him if he went on with his breakfast.

"'I was fully prepared to hear the bad news,' he explained, 'which my man Robertson told me when I arrived. The letter I got last night was a bogus one; there is no such person as J. Collins, M.D. My brother had never felt better in his life. You will, I am sure, very soon trace the cunning writer of that epistle — ah! but I was in a rage, I can tell you, when I got to the Metropole at Brighton, and found that Emile, my brother, had never heard of any Doctor Collins.

"'The last train to town had gone, although I raced back to the station as hard as I could. Poor old Robertson, he has a terrible cold. Ah yes! my loss! it is for me a very serious one; if I had not made that lucky bargain with Mr. Shipman last night I should, perhaps, at this moment be a ruined man.

"'The stones I had yesterday were, firstly, some magnificent Brazilians; these I sold to Mr. Shipman mostly. Then I had some very good Cape diamonds — all gone; and some quite special Parisians, of wonderful work and finish, entrusted to me for sale by a great French house. I tell you, sir, my loss will be nearly £10,000 altogether. I sell on commission, and, of course, have to make good the loss.'

"He was evidently trying to bear up manfully, and as a business man should, under his sad fate. He refused in any way to attach the slightest blame to his old and faithful servant Robertson, who had caught, perhaps, his death of cold in his zeal for his absent master. As for any hint of suspicion falling even remotely upon the man, the very idea appeared to Mr. Knopf absolutely preposterous.

"With regard to the old charwoman, Mr. Knopf certainly knew nothing about her, beyond the fact that she had been recommended to him by one of the tradespeople in the neighbourhood, and seemed perfectly honest, respectable, and sober.

"About the tramp Mr. Knopf knew still less, nor could he imagine how he, or in fact anybody else, could possibly know that he happened to have diamonds in his house that night.

"This certainly seemed the great hitch in the case.

"Mr. Ferdinand Knopf, at the instance of the police, later on went to the station and had a look at the suspected tramp. He declared that he had never set eyes on him before.

"Mr. Shipman, on his way home from business in the afternoon, had done likewise, and made a similar statement.

"Brought before the magistrate, the tramp gave but a poor account of himself. He gave a name and address, which latter, of course, proved to be false. After that he absolutely refused to speak. He seemed not to care whether he was kept in custody or not. Very soon even the police realized that, for the present, at any rate, nothing could be got out of the suspected tramp.

"Mr. Francis Howard, the detective, who had charge of the case, though he would not admit it even to himself, was at his wits' ends. You must remember that the burglary, through its very simplicity, was an exceedingly mysterious affair. The constable, D 21, who had stood in Adam and Eve Mews, presumably while Mr. Knopf's house was being robbed, had seen no one turn out from the cul-de-sac into the main passage of the mews.

"The stables, which immediately faced the back entrance of the Phillimore Terrace houses, were all private ones belonging to residents in the neighbourhood. The coachmen, their families, and all the grooms who slept in the stablings were rigidly watched and questioned. One and all had seen nothing, heard nothing, until Robertson's shrieks had roused them from their sleep.

"As for the letter from Brighton, it was absolutely commonplace, and written upon note-paper which the detective, with Machiavellian cunning, traced to a stationer's shop in West Street. But the trade at that particular shop was a very brisk one; scores of people had bought note-paper there, similar to that on which the supposed doctor had written his tricky letter. The handwriting was cramped, perhaps a disguised one; in any case, except under very exceptional circumstances, it could afford no clue to the identity of the thief. Needless to say, the tramp, when told to write his name, wrote a totally different and absolutely uneducated hand.

"Matters stood, however, in the same persistently mysterious state when a small discovery was made, which suggested to Mr. Francis Howard an idea, which, if properly carried out, would, he hoped, inevitably bring the cunning burglar safely within the grasp of the police.

"That was the discovery of a few of Mr. Knopf's diamonds," continued the man in the corner after a slight pause, "evidently trampled into the ground by the thief whilst making his hurried exit through the garden of No. 22, Phillimore Terrace.

"At the end of this garden there is a small studio which had been built by a former owner of the house, and behind it a small piece of waste ground about seven feet square which had once been a rockery, and is still filled with large loose stones, in the shadow of which earwigs and woodlice innumerable have made a happy hunting ground.

"It was Robertson who, two days after the robbery, having need of a large stone, for some household purpose or other, dislodged one from that piece of waste ground, and found a few shining pebbles beneath it. Mr. Knopf took them round to the police-station himself immediately, and identified the stones as some of his Parisian ones.

"Later on the detective went to view the place where the find had been made, and there conceived the plan upon which he built big cherished hopes.

"Acting upon the advice of Mr. Francis Howard, the police decided to let the anonymous tramp out of his safe retreat within the station, and to allow him to wander whithersoever he chose. A good idea, perhaps — the presumption being that, sooner or later, if the man was in any way mixed up with the cunning thieves, he would either rejoin his comrades or even lead the police to where the remnant of his hoard lay hidden; needless to say, his footsteps were to be literally dogged.

"The wretched tramp, on his discharge, wandered out of the yard, wrapping his thin coat round his shoulders, for it was a bitterly cold afternoon. He began operations by turning into the Town Hall Tavern for a good feed and a copious drink. Mr. Francis Howard noted that he seemed to eye every passer-by with suspicion, but he seemed to enjoy his dinner, and sat some time over his bottle of wine.

"It was close upon four o'clock when he left the tavern, and then began for the indefatigable Mr. Howard one of the most wearisome and uninteresting chases, through the mazes of the London streets, he ever remembers to have made. Up Notting Hill, down the slums of Notting Dale, along the High Street, beyond Hammersmith, and through Shepherd's Bush did that anonymous tramp lead the unfortunate detective, never hurrying himself, stopping every now and then at a public-house to get a drink, whither Mr. Howard did not always care to follow him.

"In spite of his fatigue, Mr. Francis Howard's hopes rose with every half-hour of this weary tramp. The man was obviously striving to kill time; he seemed to feel no weariness, but walked on and on, perhaps suspecting that he was being followed.

"At last, with a beating heart, though half perished with cold, and with terribly sore feet, the detective began to realize that the tramp was gradually working his way back towards Kensington. It was then close upon eleven o'clock at night; once or twice the man had walked up and down the High Street, from St. Paul's School to Derry and Toms' shops and back again, he had looked down one or two of the side streets and — at last — he turned into Phillimore Terrace. He seemed in no hurry, he oven stopped once in the middle of the road, trying to light a pipe, which, as there was a high east wind, took him some considerable time. Then he leisurely sauntered down the street, and turned into Adam and Eve Mews, with Mr. Francis Howard now close at his heels.

"Acting upon the detective's instructions, there were several men in plain clothes ready to his call in the immediate neighbourhood. Two stood within the shadow of the steps of the Congregational Church at the corner of the mews, others were stationed well within a soft call.

"Hardly, therefore, had the hare turned into the cul-de-sac at the back of Phillimore Terrace than, at a slight sound from Mr. Francis Howard, every egress was barred to him, and he was caught like a rat in a trap.

"As soon as the tramp had advanced some thirty yards or so (the whole length of this part of the mews is about one hundred yards) and was lost in the shadow, Mr. Francis Howard directed four or five of his men to proceed cautiously up the mews, whilst the same number were to form a line all along the front of Phillimore Terrace between the mews and the High Street.

"Remember, the back-garden walls threw long and dense shadows, but the silhouette of the man would be clearly outlined if he made any attempt at climbing over them. Mr. Howard felt quite sure that the thief was bent on recovering the stolen goods, which, no doubt, he had hidden in the rear of one of the houses. He would be caught in flagrante delicto, and, with a heavy sentence hovering over him, he would probably be induced to name his accomplice. Mr. Francis Howard was thoroughly enjoying himself.

"The minutes sped on; absolute silence, in spite of the presence of so many men, reigned in the dark and deserted mews.

"Of course, this night's adventure was never allowed to get into the papers," added the man in the corner with his mild smile. "Had the plan been successful, we should have heard all about it, with a long eulogistic article as to the astuteness of our police; but as it was — well, the tramp sauntered up the mews — and — there he remained for aught Mr. Francis Howard or the other constables could ever explain. The earth or the shadows swallowed him up. No one saw him climb one of the garden walls, no one heard him break open a door; he had retreated within the shadow of the garden walls, and was seen or heard of no more."

"One of the servants in the Phillimore Terrace houses must have belonged to the gang," said Polly with quick decision.

"Ah, yes! but which?" said the man in the corner, making a beautiful knot in his bit of string. "I can assure you that the police left not a stone unturned once more to catch sight of that tramp whom they had had in custody for two days, but not a trace of him could they find, nor of the diamonds, from that day to this."