I turned into the Rue Thiers, and at once the high, forbidding houses ceased, and small detached villas--such as are to be found in thousands round the shabby skirts of Paris--took their place. The Villa des Hortensias, clearly labelled, was nearly at the far end of the funereal street. It was rather larger than its fellows, and comprised three stories, with a small garden in front and a vast grille with a big bell, such as Parisians love when they have passed the confines of the city, and have dispensed with the security of a concierge. The grille was ajar. I entered the garden, having made sure that the bell would not sound. The facade of the house showed no light whatever. A double stone stairway of four steps led to the front door. I went up the steps, 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."