sound he slipped out of the room and was gone. Thereupon I arose and
followed as far as the doorway.

Harley was standing immediately outside in the corridor. Seeing me, he
stepped back, and: "Don't move, Knox," he said, speaking very close to
my ear. "There is someone downstairs in the hall. Wait for me here."

With that he moved stealthily off, and I stood there, my heart beating
with unusual rapidity, listening--listening for a challenge, a cry, a
scuffle--I knew not what to expect.

Cavernous and dimly lighted, the corridor stretched away to my left. On
the right it branched sharply in the direction of the gallery
overlooking the hall.

The seconds passed, but no sound rewarded my alert listening--until,
very faintly, but echoing in a muffled, church-like fashion around that
peculiar building, came a slight, almost sibilant sound, which I took
to be the gentle closing of a distant door.

Whilst I was still wondering if I had really heard this sound or merely
imagined it:

"Who goes there?" came sharply in Harley's voice.

I heard a faint click, and knew that he had shone the light of an
electric torch down into the hall.

I hesitated no longer, but ran along to join him. As I came to the head
of the main staircase, however, I saw him crossing the hall below. He