Whether Miss Polly Burton really did expect to see the man in the corner that Saturday afternoon, 'twere difficult to say; certain it is that when she found her way to the table close by the window and realized that he was not there, she felt conscious of an overwhelming sense of disappointment. And yet during the whole of the week she had, with more pride than wisdom, avoided this particular A.B.C. shop.

"I thought you would not keep away very long," said a quiet voice close to her ear.

She nearly lost her balance — where in the world had he come from? She certainly had not heard the slightest sound, and yet there he sat, in the corner, like a veritable Jack-in-the-box, his mild blue eyes staring apologetically at her, his nervous fingers toying with the inevitable bit of string.

The waitress brought him his glass of milk and a cheese-cake. He ate it in silence, while his piece of string lay idly beside him on the table. When he had finished he fumbled in his capacious pockets, and drew out the inevitable pocket-book.

Placing a small photograph before the girl, he said quietly:

"That is the back of the houses in Phillimore Terrace, which overlook Adam and Eve Mews."

She looked at the photograph, then at him, with a kindly look of indulgent expectancy.

"You will notice that the row of back gardens have each an exit into the mews. These mews are built in the shape of a capital F. The photograph is taken looking straight down the short horizontal line, which ends, as you see, in a cul-de-sac. The bottom of the vertical line turns into Phillimore Terrace, and the end of the upper long horizontal line into High Street, Kensington. Now, on that particular night, or rather early morning, of January 15th, Constable D 21, having turned into the mews from Phillimore Terrace, stood for a moment at the angle formed by the long vertical artery of the mews and the short horizontal one which, as I observed before, looks on to the back gardens of the Terrace houses, and ends in a cul-de-sac.

"How long D 21 stood at that particular corner he could not exactly say, but he thinks it must have been three or four minutes before he noticed a suspicious-looking individual shambling along under the shadow of the garden walls. He was working his way cautiously in the direction of the cul-de-sac, and D 21, also keeping well within the shadow, went noiselessly after him.

"He had almost overtaken him — was, in fact, not more than thirty yards from him — when from out of one of the two end houses — No. 22, Phillimore Terrace, in fact — a man, in nothing but his night-shirt, rushed out excitedly, and, before D 21 had time to intervene, literally threw himself upon the suspected individual, rolling over and over with him on the hard cobble-stones, and frantically shrieking, 'Thief! Thief! Police!'

"It was some time before the constable succeeded in rescuing the tramp from the excited grip of his assailant, and several minutes before he could make himself heard.

"'There! there! that'll do!' he managed to say at last, as he gave the man in the shirt a vigorous shove, which silenced him for the moment. 'Leave the man alone now, you mustn't make that noise this time o' night, wakin' up all the folks.' The unfortunate tramp, who in the meanwhile had managed to got on to his feet again, made no attempt to get away; probably he thought he would stand but a poor chance. But the man in the shirt had partly recovered his power of speech, and was now blurting out jerky, half — intelligible sentences:

"'I have been robbed — robbed — I — that is — my master — Mr. Knopf. The desk is open — the diamonds gone — all in my charge — and — now they are stolen! That's the thief — I'll swear — I heard him — not three minutes ago — rushed downstairs — the door into the garden was smashed — I ran across the garden — he was sneaking about here still — Thief! Thief! Police! Diamonds! Constable, don't let him go — I'll make you responsible if you let him go — '

"'Now then — that'll do!' admonished D 21 as soon as he could get a word in, 'stop that row, will you?'

"The man in the shirt was gradually recovering from his excitement.

"'Can I give this man in charge?' he asked.

"'What for?'

"'Burglary and housebreaking. I heard him, I tell you. He must have Mr. Knopf's diamonds about him at this moment.'

"'Where is Mr. Knopf?'

"'Out of town,' groaned the man in the shirt. 'He went to Brighton last night, and left me in charge, and now this thief has been and — '

"The tramp shrugged his shoulders and suddenly, without a word, he quietly began taking off his coat and waistcoat. These he handed across to the constable. Eagerly the man in the shirt fell on them, and turned the ragged pockets inside out. From one of the windows a hilarious voice made some facetious remark, as the tramp with equal solemnity began divesting himself of his nether garments.

"'Now then, stop that nonsense,' pronounced D 21 severely, 'what were you doing here this time o' night, anyway?'

"'The streets o' London is free to the public, ain't they?' queried the tramp.

"'This don't lead nowhere, my man.'

"'Then I've lost my way, that's all,' growled the man surlily, 'and p'raps you'll let me get along now.'

"By this time a couple of constables had appeared upon the scene. D 21 had no intention of losing sight of his friend the tramp, and the man in the shirt had again made a dash for the latter's collar at the bare idea that he should be allowed to 'get along.'

"I think D 21 was alive to the humour of the situation. He suggested that Robertson (the man in the night-shirt) should go in and get some clothes on, whilst he himself would wait for the inspector and the detective, whom D 15 would send round from the station immediately.

"Poor Robertson's teeth were chattering with cold. He had a violent fit of sneezing as D 21 hurried him into the house. The latter, with another constable, remained to watch the burglared premises both back and front, and D 15 took the wretched tramp to the station with a view to sending an inspector and a detective round immediately.

"When the two latter gentlemen arrived at No. 22, Phillimore Terrace, they found poor old Robertson in bed, shivering, and still quite blue. He had got himself a hot drink, but his eyes were streaming and his voice was terribly husky. D 21 had stationed himself in the dining-room, where Robertson had pointed the desk out to him, with its broken lock and scattered contents.

"Robertson, between his sneezes, gave what account he could of the events which happened immediately before the robbery.

"His master, Mr. Ferdinand Knopf, he said, was a diamond merchant, and a bachelor. He himself had been in Mr. Knopf's employ over fifteen years, and was his only indoor servant. A charwoman came every day to do the housework.

"Last night Mr. Knopf dined at the house of Mr. Shipman, at No. 26, lower down. Mr. Shipman is the great jeweller who has his place of business in South Audley Street. By the last post there came a letter with the Brighton postmark, and marked 'urgent,' for Mr. Knopf, and he (Robertson) was just wondering if he should run over to No. 26 with it, when his master returned. He gave one glance at the contents of the letter, asked for his A.B.C. Railway Guide, and ordered him (Robertson) to pack his bag at once and fetch him a cab.

"'I guessed what it was,' continued Robertson after another violent fit of sneezing. 'Mr. Knopf has a brother, Mr. Emile Knopf, to whom he is very much attached, and who is a great invalid. He generally goes about from one seaside place to another. He is now at Brighton, and has recently been very ill.

"'If you will take the trouble to go downstairs I think you will still find the letter lying on the hall table.

"'I read it after Mr. Knopf left; it was not from his brother, but from a gentleman who signed himself J. Collins, M.D. I don't remember the exact words, but, of course, you'll be able to read the letter — Mr. J. Collins said he had been called in very suddenly to see Mr. Emile Knopf, who, he added, had not many hours to live, and had begged of the doctor to communicate at once with his brother in London.

"'Before leaving, Mr. Knopf warned me that there were some valuables in his desk — diamonds mostly, and told me to be particularly careful about locking up the house. He often has left me like this in charge of his premises, and usually there have been diamonds in his desk, for Mr. Knopf has no regular City office as he is a commercial traveller.'

"This, briefly, was the gist of the matter which Robertson related to the inspector with many repetitions and persistent volubility.

"The detective and inspector, before returning to the station with their report, thought they would call at No. 26, on Mr. Shipman, the great jeweller.

"You remember, of course," added the man in the corner, dreamily contemplating his bit of string, "the exciting developments of this extraordinary case. Mr. Arthur Shipman is the head of the firm of Shipman and Co., the wealthy jewellers. He is a widower, and lives very quietly by himself in his own old-fashioned way in the small Kensington house, leaving it to his two married sons to keep up the style and swagger befitting the representatives of so wealthy a firm.

"'I have only known Mr. Knopf a very little while,' he explained to the detectives. 'He sold me two or three stones once or twice, I think; but we are both single men, and we have often dined together. Last night he dined with me. He had that afternoon received a very fine consignment of Brazilian diamonds, as he told me, and knowing how beset I am with callers at my business place, he had brought the stones with him, hoping, perhaps, to do a bit of trade over the nuts and wine.

"'I bought £25,000 worth of him,' added the jeweller, as if he were speaking of so many farthings, 'and gave him a cheque across the dinner table for that amount. I think we were both pleased with our bargain, and we had a final bottle of '48 port over it together. Mr. Knopf left me at about 9.30, for he knows I go very early to bed, and I took my new stock upstairs with me, and locked it up in the safe. I certainly heard nothing of the noise in the mews last night. I sleep on the second floor, in the front of the house, and this is the first I have heard of poor Mr. Knopf's loss — '

"At this point of his narrative Mr. Shipman very suddenly paused, and his face became very pale. With a hasty word of excuse he unceremoniously left the room, and the detective heard him running quickly upstairs.

"Less than two minutes later Mr. Shipman returned. There was no need for him to speak; both the detective and the inspector guessed the truth in a moment by the look upon his face.

"'The diamonds!' he gasped. 'I have been robbed.'"