Still my curiosity remained unsatisfied; still over the room itself hung a veil of mystery which I would fain have lifted. All my visits to the room to see whether the light shone under the door had hitherto been made previously to the midnight visits of Sister Agnes. The question that now arose in my mind was whether the mysterious thread of light was or was not visible after Sister Agnes's customary visit--whether, in fact, it shone there all the night through. In order to solve this doubt I lay awake the night following that of my discovery of Sister Agnes. Listening intently, with my bedroom door ajar, I heard her go upstairs, and ten minutes later I could just distinguish her smothered footfall as she came down. I heard the door at the bottom of the corridor shut behind her, and then I knew that I was safe. Slipping out of bed, I stole, barefooted as I was, out of my bedroom and up the flight of stairs which led to the black door. Of ghosts in the ordinary meaning of that word--in the meaning which it has for five children out of six--I had no fear: my fears, such as they were, ran in quite another groove. I went upstairs slowly, with shut eyes, counting each stair as I put my feet on it from one up to ten. I knew that from the tenth stair the streak of light, if there, would be visible. On the tenth stair I opened my eyes. There was the thread of light shining clear and steady under the black door. For a minute I stood looking at it. In the intense silence the beating of my heart was painfully audible. Grasping the banister with one hand, I went down stairs backwards, step by step, and so regained the sanctuary of my own room. I scarcely know in what terms to describe, or how to make sufficiently clear, the strange sort of fascination there was for me in those nightly rambles--in living perpetually on the edge of a mystery. While daylight lasted the feeling slumbered within me; I could even take myself to task for wanting to pry into a secret that evidently in nowise concerned me. But as soon as twilight set in, and night's shadows began to creep timidly out of their corners, so surely could I feel the spell working within me, the desire creeping over me to pluck out the heart of the mystery that lay hidden behind the black nail-studded door upstairs. Sometimes I clomb the staircase at one hour, sometimes at another; but there was no real sleep for me, nothing but fitful uneasy dozes, till the brief journey had been made. After climbing to the tenth stair, and satisfying myself that the light was there, I would creep back noiselessly to bed, and fall at once into a deep dreamless sleep that was often prolonged till late in the forenoon.