Cautious fingering revealed closely matched hard wood, studded thickly with nail heads, but no keyhole or latch.

Secure in the feeling that no one else could be in this outer passage, and completely baffled, I ventured to strike a match.

The tiny yellow flame, ere it quickly flickered out in some mysterious draft, revealed an iron band to the left of the door, with slight protuberance, resembling the button of an electric-bell.

This was the only semblance to a lock, and I was in doubt whether it would prove an alarm, or some ingenuous [Transcriber's note: ingenious ?] spring.

There was nothing for it, however, but to try the experiment, and face the result.
Almost convinced that the pressure of my finger would ring an electric bell, I drew my revolver, and crouched low, prepared for any emergency, as I pressed the metal button.