the detective’s scheme was simplicity itself, and it promised success. he had merely instructed stickney to have stone’s bell rung at the appointed time, and to keep it ringing continuously until the miner should leave his room in desperation to complain of the nuisance.

if it worked out as nick hoped, stone’s absence would give him the opportunity he sought, and meanwhile the miner would be informed that the electrical apparatus must have been deranged in some way. it would be looked to and “remedied;” whereupon, the ringing would cease, and stone would receive the apologies of the management.

nick assumed, however, that the miner would first telephone downstairs. the din would make it difficult for him to be understood, though; and even if he were, he would doubtless grow impatient at the delay and soon leave his room to complain in person to the clerk.

the fact that he was already dressed would make that easy, and nick counted on his doing so sooner or later. at any rate, he had arranged with stickney that the bell should continue its exasperating dinning if possible until stone had been routed out.

on the other hand, there was a possibility, of course, that the man would not act in accordance with expectations. he might remain at the telephone, or even demolish the bell in his anger, especially as he would doubtless be afraid that it would arouse crawford, and that the latter might not fall asleep again for some time. nick had to run that risk, though; and now he was impatiently awaiting some sign that his ruse was working as he wished.

the muffled ringing of the bell prevented him from telling whether stone was telephoning or not, but he had no doubt that such was the case. would the man stop at that, though?

evidently not; for two or three minutes after the bell began to ring he caught the sound of an opening door, despite the racket, and almost immediately afterward hurried footsteps passed his room.

he waited for nothing more, but crawled through his window near to the neighboring platform of the fire escape and laid hands on stone’s sash. it came up easily, and revealed an empty room, and the door ajar. it was a risky undertaking, and one that was full of uncertainties. the irate miner might return at any moment. crawford might come in from the adjoining room and denounce him as a suspicious character, or some one else might put in an appearance to investigate the noise which must have been disturbing many by that time. worst of all, stone had left the door partly open and the light on, so that nick had to work in the open, with a possibility of being seen and interrupted at any moment.

none of these things seemed to worry him, though. he slipped cautiously into the room and looked about him with keen eyes. a faint ejaculation of satisfaction escaped his lips as he caught sight of what he was looking for.

there was a small writing desk close to the head of the bed. it was open, and on the extended leaf lay a small, flat, leather case. leaping forward, nick opened the case and took out a small hypodermic syringe. the plunger had been drawn back to its fullest extent, and the detective’s lips tightened as he realized that in that little cylinder lurked sure death.

he paid no attention to the other articles in the case—the tiny bottle with some colorless drug, the bit of sponge, and so on. he cared nothing for them, and was interested only in the deadly hypodermic.

looking about him again, and listening all the while, he took out his fountain pen, removed the cap, and unscrewed the pen itself; then he squirted the contents of the syringe into the barrel of the pen, which he had taken the precaution to empty before leaving his room, and replaced the pen and cap.

having finished that manipulation, he carelessly thrust the pen back into his pocket and went with long, silent strides to a stationary washstand in a little alcove. he turned on the faucets, directed a little stream of warm water into the syringe, and operated the plunger several times, in order to clean the cylinder as well as he could; after which he filled the syringe with water, and, leaving the plunger out as he had found it, returned the instrument to the case. the case closed, he made for the window.

so swift had been his movements that he had been in the room hardly more than a minute, and nothing had occurred to disturb him. the bell had continued its deafening ringing, and he had thought he heard crawford’s bed creak, but stone’s partner had not called out. he gave a sigh of relief as he reached the balcony of the fire escape and plunged out into the shadows at one side. in a few brief moments he was over the railing and through his own window.

he had hardly reached his room, however, before he heard stone’s familiar footsteps in the corridor outside. the miner was returning, and muttering angrily to himself as he did so. presently the noise ceased. the bell had been “fixed.” the detective heard stone pass again and yet again, probably to tell the floor clerk that it was all right.

not until stone’s door was finally closed and locked did the detective drop into a chair. “whew!” he said, half aloud, “that was warm work, and not very good for the nerves. i’ve saved crawford for the time being, but my work isn’t done by any means—even for to-night.”

he looked at his watch and found that it was quarter past one. there was still an hour and a quarter if stone obeyed instructions, and nick had no doubt that he would now. in fact, he might even wait longer, for he would be certain to fear that the ringing of the bell had disturbed crawford, and would wish to give him plenty of time to fall into a deep sleep again.

nick did not intend to remain idle, but he felt sure that he had some time to kill, and he was glad of it. despite his iron nerve, he felt just a trifle shaken by the exacting ordeal through which he had just gone; therefore, he took out a cigar, lighted it, and leaned back in a morris chair. he must have dozed off before long, for the next thing he knew he sat up with a start. it was half past two.

“stone will probably be making a move now,” he thought, on the alert at once. “i’m glad my mental alarm clock woke me when it did.”