and was about to knock, when the idea flashed
across my mind: "Suppose that Deschamps is really dying, how am I to
explain my presence here? I am not the guardian of Rosa, and she may
resent being tracked across Paris by a young man with no claim to
watch her actions."

Nevertheless, in an expedition of this nature one must accept risks,
and therefore I knocked gently. There was no reply to the summons, and
I was cogitating upon my next move when, happening to press against
the door with my hand, I discovered that it was not latched. Without
weighing consequences, I quietly opened it, and with infinite caution
stepped into the hall, and pushed the door to. I did not latch it,
lest I might need to make a sudden exit--unfamiliar knobs and springs
are apt to be troublesome when one is in a hurry.

I was now fairly in the house, but the darkness was blacker than the
pit, and I did not care to strike a match. I felt my way along by the
wall till I came to a door on the left; it was locked. A little
further was another door, also locked. I listened intently, for I
fancied I could hear a faint murmur of voices, but I was not sure.
Then I startled myself by stepping on nothing--I was at the head of a
flight of stone steps; down below I could distinguish an almost
imperceptible glimmer of light.

"I'm in for it. Here goes!" I reflected, and I crept down the steps
one by one, and in due course reached the bottom. To the left was a
doorway, through which came the glimmer of light. Passing through the
doorway, I came into a room with a stone floor. The light, which was
no stronger than the very earliest intimation of a winter's dawn,
seemed to issue in a most unusual way from the far corner of this
apartment near the ceiling. I directed my course towards it, and in
the transit made violent contact with some metallic object, which
proved to be an upright iron shaft, perhaps three inches in diameter,
running from floor to ceiling.

"Surely," I thought, "this is the queerest room I was ever in."

Circumnavigating the pillar, I reached the desired corner, and stood
under the feeble source of light. I could see now that in this corner
the ceiling was higher than elsewhere, and that the light shone dimly
from a perpendicular pane of glass which joined the two levels of the
ceiling. I also saw that there was a ledge about two feet from the
floor, upon which a man would stand in order to look through the
pane.

I climbed on to the