"That question of motive is a very difficult and complicated one at times," said the man in the corner, leisurely pulling off a huge pair of flaming dog-skin gloves from his meagre fingers. "I have known experienced criminal investigators declare, as an infallible axiom, that to find the person interested in the committal of the crime is to find the criminal.

"Well, that may be so in most cases, but my experience has proved to me that there is one factor in this world of ours which is the mainspring of human actions, and that factor is human passions. For good or evil passions rule this poor humanity of ours. Remember, there are the women! French detectives, who are acknowledged masters in their craft, never proceed till after they have discovered the feminine element in a crime; whether in theft, murder, or fraud, according to their theory, there is always a woman.

"Perhaps the reason why the Phillimore Terrace robbery was never brought home to its perpetrators is because there was no woman in any way connected with it, and I am quite sure, on the other hand, that the reason why the thief at the English Provident Bank is still unpunished is because a clever woman has escaped the eyes of our police force."

He had spoken at great length and very dictatorially. Miss Polly Burton did not venture to contradict him, knowing by now that whenever he was irritable he was invariably rude, and she then had the worst of it.

"When I am old," he resumed, "and have nothing more to do, I think I shall take professionally to the police force; they have much to learn."

Could anything be more ludicrous than the self-satisfaction, the abnormal conceit of this remark, made by that shrivelled piece of mankind, in a nervous, hesitating tone of voice? Polly made no comment, but drew from her pocket a beautiful piece of string, and knowing his custom of knotting such an article while unravelling his mysteries, she handed it across the table to him. She positively thought that he blushed.

"As an adjunct to thought," she said, moved by a conciliatory spirit.

He looked at the invaluable toy which the young girl had tantalisingly placed close to his hand: then he forced himself to look all round the coffee-room: at Polly, at the waitresses, at the piles of pallid buns upon the counter. But, involuntarily, his mild blue eyes wandered back lovingly to the long piece of string, on which his playful imagination no doubt already saw a series of knots which would be equally tantalising to tie and to untie.

"Tell me about the theft at the English Provident Bank," suggested Polly condescendingly.

He looked at her, as if she had proposed some mysterious complicity in an unheard-of crime. Finally his lean fingers sought the end of the piece of string, and drew it towards him. His face brightened up in a moment.

"There was an element of tragedy in that particular robbery," he began, after a few moments of beatified knotting, "altogether different to that connected with most crimes; a tragedy which, as far as I am concerned, would seal my lips for ever, and forbid them to utter a word, which might lead the police on the right track."

"Your lips," suggested Polly sarcastically, "are, as far as I can see, usually sealed before our long-suffering, incompetent police and — "

"And you should be the last to grumble at this," he quietly interrupted, "for you have spent some very pleasant half-hours already, listening to what you have termed my 'cock-and-bull' stories. You know the English Provident Bank, of course, in Oxford Street; there were plenty of sketches of it at the time in the illustrated papers. Here is a photo of the outside. I took it myself some time ago, and only wish I had been cheeky or lucky enough to get a snap-shot of the interior. But you see that the office has a separate entrance from the rest of the house, which was, and still is, as is usual in such cases, inhabited by the manager and his family.

"Mr. Ireland was the manager then; it was less than six months ago. He lived over the bank, with his wife and family, consisting of a son, who was clerk in the business, and two or three younger children. The house is really smaller than it looks on this photo, for it has no depth, and only one set of rooms on each floor looking out into the street, the back of the house being nothing but the staircase. Mr. Ireland and his family, therefore, occupied the whole of it.

"As for the business premises, they were, and, in fact, are, of the usual pattern; an office with its rows of desks, clerks, and cashiers, and beyond, through a glass door, the manager's private room, with the ponderous safe, and desk, and so on.

"The private room has a door into the hall of the house, so that the manager is not obliged to go out into the street in order to go to business. There are no living-rooms on the ground floor, and the house has no basement.

"I am obliged to put all these architectural details before you, though they may sound rather dry and uninteresting, but they are really necessary in order to make my argument clear.

"At night, of course, the bank premises are barred and bolted against the street, and as an additional precaution there is always a night watchman in the office. As I mentioned before, there is only a glass door between the office and the manager's private room. This, of course, accounted for the fact that the night watchman heard all that he did hear, on that memorable night, and so helped further to entangle the thread of that impenetrable mystery.

"Mr. Ireland as a rule went into his office every morning a little before ten o'clock, but on that particular morning, for some reason which he never could or would explain, he went down before having his breakfast at about nine o'clock. Mrs. Ireland stated subsequently that, not hearing him return, she sent the servant down to tell the master that breakfast was getting cold. The girl's shrieks were the first intimation that something alarming had occurred.

"Mrs. Ireland hastened downstairs. On reaching the hall she found the door of her husband's room open, and it was from there that the girl's shrieks proceeded.

"'The master, mum — the poor master — he is dead, mum — I am sure he is dead!' — accompanied by vigorous thumps against the glass partition, and not very measured language on the part of the watchman from the outer office, such as — 'Why don't you open the door instead of making that row?'

"Mrs. Ireland is not the sort of woman who, under any circumstances, would lose her presence of mind. I think she proved that throughout the many trying circumstances connected with the investigation of the case. She gave only one glance at the room and realized the situation. On the arm-chair, with head thrown back and eyes closed, lay Mr. Ireland, apparently in a dead faint; some terrible shock must have very suddenly shattered his nervous system, and rendered him prostrate for the moment. What that shock had been it was pretty easy to guess.

"The door of the safe was wide open, and Mr. Ireland had evidently tottered and fainted before some awful fact which the open safe had revealed to him; he had caught himself against a chair which lay on the floor, and then finally sunk, unconscious, into the arm-chair.

"All this, which takes some time to describe," continued the man in the corner, "took, remember, only a second to pass like a flash through Mrs. Ireland's mind; she quickly turned the key of the glass door, which was on the inside, and with the help of James Fairbairn, the watchman, she carried her husband upstairs to his room, and immediately sent both for the police and for a doctor.

"As Mrs. Ireland had anticipated, her husband had received a severe mental shock which had completely prostrated him. The doctor prescribed absolute quiet, and forbade all worrying questions for the present. The patient was not a young man; the shock had been very severe — it was a case, a very slight one, of cerebral congestion — and Mr. Ireland's reason, if not his life, might be gravely jeopardised by any attempt to recall before his enfeebled mind the circumstances which had preceded his collapse.

"The police therefore could proceed but slowly in their investigations. The detective who had charge of the case was necessarily handicapped, whilst one of the chief actors concerned in the drama was unable to help him in his work.

"To begin with, the robber or robbers had obviously not found their way into the manager's inner room through the bank premises. James Fairbairn had been on the watch all night, with the electric light full on, and obviously no one could have crossed the outer office or forced the heavily barred doors without his knowledge.

"There remained the other access to the room, that is, the one through the hall of the house. The hall door, it appears, was always barred and bolted by Mr. Ireland himself when he came home, whether from the theatre or his club. It was a duty he never allowed any one to perform but himself. During his annual holiday, with his wife and family, his son, who usually had the sub-manager to stay with him on those occasions, did the bolting and barring — but with the distinct understanding that this should be done by ten o'clock at night.

"As I have already explained to you, there is only a glass partition between the general office and the manager's private room, and, according to James Fairbairn's account, this was naturally always left wide open so that he, during his night watch, would of necessity hear the faintest sound. As a rule there was no light left in the manager's room, and the other door — that leading into the hall — was bolted from the inside by James Fairbairn the moment he had satisfied himself that the premises were safe, and he had begun his night-watch. An electric bell in both the offices communicated with Mr. Ireland's bedroom and that of his son, Mr. Robert Ireland, and there was a telephone installed to the nearest district messengers' office, with an understood signal which meant 'Police.'

"At nine o'clock in the morning it was the night watchman's duty, as soon as the first cashier had arrived, to dust and tidy the manager's room, and to undo the bolts; after that he was free to go home to his breakfast and rest.

"You will see, of course, that James Fairbairn's position in the English Provident Bank is one of great responsibility and trust; but then in every bank and business house there are men who hold similar positions. They are always men of well-known and tried characters, often old soldiers with good-conduct records behind them. James Fairbairn is a fine, powerful Scotchman; he had been night watchman to the English Provident Bank for fifteen years, and was then not more than forty-three or forty-four years old. He is an ex-guardsman, and stands six feet three inches in his socks.

"It was his evidence, of course, which was of such paramount importance, and which somehow or other managed, in spite of the utmost care exercised by the police, to become public property, and to cause the wildest excitement in banking and business circles.

"James Fairbairn stated that at eight o'clock in the evening of March 25th, having bolted and barred all the shutters and the door of the back premises, he was about to lock the manager's door as usual, when Mr. Ireland called to him from the floor above, telling him to leave that door open, as he might want to go into the office again for a minute when he came home at eleven o'clock. James Fairbairn asked if he should leave the light on, but Mr. Ireland said: 'No, turn it out. I can switch it on if I want it.'

"The night watchman at the English Provident Bank has permission to smoke, he also is allowed a nice fire, and a tray consisting of a plate of substantial sandwiches and one glass of ale, which he can take when he likes. James Fairbairn settled himself in front of the fire, lit his pipe, took out his newspaper, and began to read. He thought he had heard the street door open and shut at about a quarter to ten; he supposed that it was Mr. Ireland going out to his club, but at ten minutes to ten o'clock the watchman heard the door of the manager's room open, and some one enter, immediately closing the glass partition door and turning the key.

"He naturally concluded it was Mr. Ireland himself.

"From where he sat he could not see into the room, but he noticed that the electric light had not been switched on, and that the manager seemingly had no light but an occasional match.

"'For the minute,' continued James Fairbairn, 'a thought did just cross my mind that something might perhaps be wrong, and I put my newspaper aside and went to the other end of the room towards the glass partition. The manager's room was still quite dark, and I could not clearly see into it, but the door into the hall was open, and there was, of course, a light through there. I had got quite close to the partition, when I saw Mrs. Ireland standing in the doorway, and heard her saying in a very astonished tone of voice: 'Why, Lewis, I thought you had gone to your club ages ago. What in the world are you doing here in the dark?'

"'Lewis is Mr. Ireland's Christian name,' was James Fairbairn's further statement. 'I did not hear the manager's reply, but quite satisfied now that nothing was wrong, I went back to my pipe and my newspaper. Almost directly afterwards I heard the manager leave his room, cross the hall and go out by the street door. It was only after he had gone that I recollected that he must have forgotten to unlock the glass partition and that I could not therefore bolt the door into the hall the same as usual, and I suppose that is how those confounded thieves got the better of me.'"