I doubted that a snake of his great girth could ascend this relatively tiny strand; but, not caring to take the chance, I drew the rope up and looped it over the beam. For the moment, at least, I was safe, and I breathed a deep sigh of relief. Then I looked about me. The shadows were dense and almost impenetrable, yet it appeared that the ceiling of the room was still far above me; about me was a maze of beams and braces and trusses. I determined to explore this upper region of the room of the seven doors. Standing upright upon the beam, I moved cautiously toward the wall. At the end of the beam I discovered a narrow walkway that, clinging to the wall, apparently encircled the room. It was two feet wide and had no handrail. It seemed to be something in the nature of a scaffolding left by the workmen who had constructed the building. As I took my exploratory way along it, feeling each step carefully and brushing the wall with my hand, I again heard the agonized scream that had twice before attracted my attention if not my keenest interest; for I was still more interested in my troubles than in those of some unknown female of this alien race. And a moment later my fingers came in contact with something that drove all thoughts of screaming women from my mind. By feel, it was the frame of a door or of a window. With both hands I examined my find. Yes, it was a door! It was a narrow door about six feet in height. I felt the hinges; I searched for a latch--and at last I found it. Cautiously I manipulated it and presently I felt the door move toward me. What lay beyond? Some new and fiendishly conceived form of death or torture, perhaps; perhaps freedom. I could not know without opening that portal of mystery. I hesitated, but not for long. Slowly I drew the door toward me, an eye close to the widening crack. A breath of night air blew in upon me; I saw the faint luminosity of a Venusan night. Could it be possible that with all their cunning the Thorists had inadvertently left this avenue of escape from this lethal chamber? I could scarcely credit it, yet there was naught that I could do but go on and chance whatever lay beyond. I opened the door and stepped out upon a balcony which extended in both directions until it passed from the range of my vision beyond the curve of the circular wall to which it clung. At the outer edge of the balcony was a low parapet behind which I now crouched while I reconnoitered my new situation. No new danger seemed to threaten me, yet I was still suspicious. I moved cautiously forward upon a tour of investigation, and again an agonized scream rent the silence of the night. This time it seemed quite close; previously, the walls of the building in which I had been imprisoned had muffled it. * * * * *