So intent had he become upon the picture before him that he had not noticed the fact that he was alone in the office of the Congo Fibre Company. Now he realized it from the absolute silence about him, and from another circumstance.
The spying apparatus had been left focussed, and on to the screen beneath his eyes, bending low behind the desks and creeping, Indian-like, around, toward the head of the stair which communicated with the strongroom and the apartment used by the messenger, came the alert figure of Earl Dexter!
It may be a surprise to some people to learn that at any time in the day the door of a bank, unguarded, should be left open, when only a solitary messenger is within the premises; yet for a few minutes at least each evening this happens at more than one City bank, where one of the duties of the resident messenger is to clean the outer steps. Dexter had taken advantage of the man's absence below in quest of scrubbing material to enter the bank through the open door.
Watching, breathless, and utterly forgetful of his own position, Bristol saw the messenger, all unconscious of danger, come up the stairs carrying a pail and broom. As his head reached the level of the railings The Stetson Man neatly sand-bagged him, rushed across to the outer door, and closed it!
Given duplicate keys and the private information which Dexter so ingeniously had obtained, there are many London banks vulnerable to similar attack. Certainly, bullion is rarely kept in a branch storeroom, but the detective was well aware that the keys of the case containing the slipper were kept in this particular safe!
He was convinced, and could entertain no shadowy doubt, that at last Dexter had triumphed. He wondered if it had ever hitherto fallen to the lot of a representative of the law thus to be made an accessory to a daring felony!
But human endurance has well-defined limits. The fading light rendered the ingenious picture dim and more dim. The pain occasioned by his position became agonizing, and uttering a stifled groan he ceased to take an interest in the robbery of the London County and Provincial Bank.
Fate is a comedian; and when later I learned how I had lain strapped to my bed, and, so near to me, Bristol had hung helpless as a butchered carcass in the office of the Congo Fibre Company, whilst, in our absence from the stage, the drama of the slipper marched feverish to its final curtain, I accorded Fate her well-earned applause. I laughed; not altogether mirthfully.