Determined, if possible, to keep the creature in view, I started in pursuit.  Up the uncarpeted stairs I went, and, from the rail of the landing, looked down into the blackness of the hallway apprehensively.  Nothing stirred below.  The marmoset had disappeared between the half-opened leaves of a large folding door.  Casting the beam of light ahead of me I followed.  I found myself in a long, lofty apartment, evidently a drawing-room.

Of the quarry I could detect no sign; but the only other door of the room was closed; therefore, since the creature had entered, it must, I argued, undoubtedly be concealed somewhere in the apartment.  Flashing the light about to right and left, I presently perceived that a conservatory (no doubt facing on the square) ran parallel with one side of the room.  French windows gave access to either end of it; and it was through one of these, which was slightly open, that the questioning ray had intruded.

I stepped into the conservatory.  Linen blinds covered the windows, but a faint light from outside found access to the bare, tiled apartment.  Ten paces on my right, from an aperture once closed by a square wooden panel that now lay upon the floor, the marmoset was grimacing at me.

Realizing that the ray of my lamp must be visible through the blinds from outside, I extinguished it ... and, a moving silhouette against a faintly luminous square, I could clearly distinguish the marmoset watching me.

There was a light in the room beyond!

The marmoset disappeared—­and I became aware of a faint, incense-like perfume.  Where had I met with it before?  Nothing disturbed the silence of the empty house wherein I stood; yet I hesitated for several seconds to pursue the chase further.  The realization came to me that the hole in the wall communicated with the conservatory of the corner house in the square, the house with the lighted windows.

Determined to see the thing through, I discarded my overcoat—­and crawled through the gap.  The smell of burning perfume became almost overpowering, as I stood upright, to find myself almost touching curtains of some semi-transparent golden fabric draped in the door between the conservatory and the drawing-room.

Cautiously, inch by inch, I approached my eyes to the slight gap in the draperies, as, from somewhere in the house below, sounded the clangor of a brazen gong.  Seven times its ominous note boomed out.  I shrank back into my sanctuary; the incense seemed to be stifling me.

CHAPTER XXXII

SHRINE OF SEVEN LAMPS

Never can I forget that nightmare apartment, that efreet’s hall.  It was identical in shape with the room of the adjoining house through which I had come, but its walls were draped in somber black and a dead black carpet covered the entire floor.  A golden curtain—­similar to that which concealed me—­broke the somber expanse of the end wall to my right, and the door directly opposite my hiding-place was closed.