The lightning passed away: utter darkness again surrounded him; and he was unable to ascertain what that black square, so well defined and apparent upon the dirty floor, could be. An indescribable sensation of fear crept over him; and the perspiration broke out upon his forehead in large drops. His knees bent beneath him; and, retreating a few steps, he leaned against the door-posts for support. He was alone--in an uninhabited house, in the midst of a horrible neighbourhood; and all the fearful tales of midnight murders which he had ever heard or read, rushed to his memory: then, by a strange but natural freak of the fancy, those appalling deeds of blood and crime were suddenly associated with that incomprehensible but ominous black square upon the floor. He was in the midst of this terrible waking dream--this more than ideal nightmare--when hasty steps approached the front door from the street; and, without stopping, entered the passage. The youth crept silently towards the farther end, the perspiration oozing from every pore. He felt the staircase with his hands; the footsteps advanced; and, light as the fawn, he hurried up the stairs. So noiseless were his motions, that his presence was not noticed by the new-comers, who in their turns also ascended the staircase. The youth reached a landing, and hastily felt for the doors of the rooms with which it communicated. In another moment he was in a chamber, at the back part of the house. He closed the door, and placed himself against it with all his strength--forgetful, poor youth! that his fragile form was unavailing, with all its power, against even the single arm of a man of only ordinary strength. Meantime the new-comers ascended the stairs. CHAPTER II. THE MYSTERIES OF THE OLD HOUSE. Fortunately for the interesting young stranger, the individuals who had just entered the house did not attempt the door of the room in which he had taken refuge. They proceeded straight--and with a steadiness which seemed to indicate that they knew the locality well--to the front chamber upon the same floor. In a few moments there was a sharp grating noise along the wall; and then a light suddenly shone into the room where the young stranger was concealed. He cast a terrified glance around, and beheld a small square window in the wall, which separated the two apartments. It was about five feet from the floor--a height which permitted the youth to avail himself of it, in order to reconnoitre the proceedings in the next room.