The footsteps receded down the stairs.  And my thoughts reverted into the old channels of dull despair.

I weighed the chances of Bristol’s seeking me there; and, eager as I was to give them substance, found them but airy—­ultimately was forced to admit them to be nil.

So I lay, whilst only a few hundred yards from me a singular scene was being enacted.  Bristol, a prisoner as helpless as myself, watched the concluding business of the day being conducted in the bank beneath him; he watched the lift descend to the strongroom —­the spying apparatus being slightly adjusted in some way; he saw the clerks hastening to finish their work in the outer office, and as he watched, absorbed by the novelty of the situation, he almost forgot the pain and discomfort which he suffered . . .

“This little peep-show of ours has been real useful,” Dexter confided out of the darkness.  “I got an impression of the key of the strongroom door a week ago, and Carneta got one of the keys of the safe only this morning, when she lodged her box of jewellery with the bank!  I was at work on that key when you interrupted me, and as by means of this useful apparatus I have learnt the combination, you ought to see some fun in the next few hours!”

Bristol repressed a groan, for the prospect of remaining in that position was thus brought keenly home to him.

The bank staff left the premises one by one until only a solitary clerk worked on at a back desk.  His task completed, he, too, took his departure and the bank messenger commenced his nightly duty of sweeping up the offices.  It was then that excitement like an anaesthetic dulled the detective’s pain—­indeed, he forgot his aching body and became merely a watchful intelligence.

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!