Read the following passage carefully, and then answer all the questions.
In this passage the narrator returns to an old house in which he hid something several years before. He thinks that the house is empty and deserted.
THE HIDDEN BOX I opened the iron gate and walked as softly as I could up the weed-tufted gravel drive. My mind was strangely empty. I felt no glow of pleasure and was unexcited at the prospect of becoming rich. I was occupied only with the mechanical task of finding a black box. The front door was closed and set far back in a very deep porch. The wind and rain had whipped a coating of gritty dust against the panels and deep into the crack where the door opened, showing that it had been shut for years. Standing on a derelict flower-bed, I tried to push open the first window on the left. It yielded to my strength, raspingly and stubbornly. I clambered through the opening and found myself, not at once in a room, but crawling along the deepest window-ledge I had ever seen. After I had jumped noisily down upon the floor, I looked up and the open window seemed very far away and much too small to have admitted me. The room where I found myself was thick with dust, musty and empty of all furniture. Spiders had erected great stretchings of their webs about the fireplace. I made my way quickly to the hall, threw open the door of the room where the box was and paused on the threshold. It was a dark morning and the weather had stained the windows with blears of grey wash which kept the brightest part of the weak light from coming in. The far corner of the room was a blur of shadow. I had a sudden urge to have done with my task and be out of this house forever. I walked across the bare boards, knelt down in the corner and passed my hands about the floor in search of the loose board. To my surprise I found it easily. It was about two feet in length and rocked hollowly under my hand. I lifted it up, laid it aside and struck a match. I saw a black metal cash-box nestling dimly in the hole. I put my hand down and crooked a finger into the loose reclining handle, but the match suddenly flickered and went out and the handle of the box, which I had lifted up about an inch, slid heavily off my finger. Without stopping to light another match, I thrust my hand into the opening and, just when it should be closing about the box, something happened. I cannot hope to describe what it was but it had frightened me very much. It was some change which came upon me or upon the room, indescribably subtle, yet momentous. It was as if the daylight had changed with unnatural suddenness, as if the temperature had altered greatly in an instant or as if the air had become twice as rare or twice as dense as it had been in the twinkling of an eye. Perhaps all of these, or other things, happened together, for all my senses were bewildered all at once and could give me no explanation. The fingers of my right hand, thrust in the opening in the floor, had closed mechanically, found nothing at all, and came up again empty. The box had gone!
I heard a cough behind me, soft and natural, yet more disturbing than any sound that could ever come upon the human ear. That I did not die of fright was due, I think, to two things: the fact that my senses were already disarranged and able to interpret to me only gradually what they had perceived, and also the fact that the utterance of the cough seemed to bring with it some more awful alteration in everything. It was as if the universe stood still for an instant, suspending the planets in their courses. I collapsed weakly from my kneeling backwards into a limp sitting-down position upon the floor. Sweat broke out on my brow and my eyes remained open for a long time without a wink, glazed and almost sightless. In the darkest corner of the room, near the window, a man was sitting in a chair, eyeing me with a mild but unwavering interest.
