“Mr. Ireland absolutely denied having been in his office at the hour when James Fairbairn positively asserted he heard Mrs. Ireland say in an astonished tone of voice:  ’Why, Lewis, what in the world are you doing here?’ It became pretty clear therefore that James Fairbairn’s view of the manager’s wife had been a mere vision.

“Mr. Ireland gave up his position as manager of the English Provident:  both he and his wife felt no doubt that on the whole, perhaps, there had been too much talk, too much scandal connected with their name, to be altogether advantageous to the bank.  Moreover, Mr. Ireland’s health was not so good as it had been.  He has a pretty house now at Sittingbourne, and amuses himself during his leisure hours with amateur horticulture, and I, who alone in London besides the persons directly connected with this mysterious affair, know the true solution of the enigma, often wonder how much of it is known to the ex-manager of the English Provident Bank.”

The man in the corner had been silent for some time.  Miss Polly Burton, in her presumption, had made up her mind, at the commencement of his tale, to listen attentively to every point of the evidence in connection with the case which he recapitulated before her, and to follow the point, in order to try and arrive at a conclusion of her own, and overwhelm the antediluvian scarecrow with her sagacity.

She said nothing, for she had arrived at no conclusion; the case puzzled every one, and had amazed the public in its various stages, from the moment when opinion began to cast doubt on Mr. Ireland’s honesty to that when his integrity was proved beyond a doubt.  One or two people had suspected Mrs. Ireland to have been the actual thief, but that idea had soon to be abandoned.

Mrs. Ireland had all the money she wanted; the theft occurred six months ago, and not a single bank-note was ever traced to her pocket; moreover, she must have had an accomplice, since some one else was in the manager’s room that night; and if that some one else was her accomplice, why did she risk betraying him by speaking loudly in the presence of James Fairbairn, when it would have been so much simpler to turn out the light and plunge the hall into darkness?

“You are altogether on the wrong track,” sounded a sharp voice in direct answer to Polly’s thoughts—­“altogether wrong.  If you want to acquire my method of induction, and improve your reasoning power, you must follow my system.  First think of the one absolutely undisputed, positive fact.  You must have a starting-point, and not go wandering about in the realms of suppositions.”

“But there are no positive facts,” she said irritably.

“You don’t say so?” he said quietly.  “Do you not call it a positive fact that the bank safe was robbed of L5000 on the evening of March 25th before 11.30 p.m.”

“Yes, that is all which is positive and—­”

“Do you not call it a positive fact,” he interrupted quietly, “that the lock of the safe not being picked, it must have been opened by its own key?”