The Tocsin had never failed him yet.
It was possible that something was afoot around him, quite probable, indeed, since he was in the most vicious part of the city, in the heart of gangland; but whatever it might be, it was certainly extraneous to his mission or she would have mentioned it.
The lane was empty now, he was quite sure of that--and there was no further sound from the window opposite.

He started forward once more--only to halt again for the second time as abruptly as before, squeezing if possible even more closely against the wall.

Some one had turned into the lane from the sidewalk, and, walking hurriedly, choosing with evident precaution the exact centre of the alleyway, came toward him.
The man passed, his hurried stride a half run; and, a few feet beyond, halted at old Isaac's side door.

From somewhere inside the old building Jimmie Dale's ears caught the faint ringing of an electric bell; a long ring, followed in quick succession by three short ones--then the repeated clicking of a latch, as though pulled by a cord from above, and the man passed in through the door, closing it behind him.
Jimmie Dale nodded to himself in the darkness.

It was a spring lock; the signal was one long ring and three short ones--the Tocsin had not missed even those small details.