The pent-up agony at last found utterance. She shrieked, and, instantly, her eyes were open, and her limbs free. She jumped out of bed, and was about to rush into the chamber of horrors, when she saw the bright light of the gas yet shining through the crack beneath her door. She listened. The house was still as the grave. Not a sound from all the world outside, except the striking of a fire alarm for the seventh district. The deep notes vibrated upon her quickened hearing like a knell. Then she remembered that, in the vision, the light had disappeared. Here it was gleaming under her door as brightly as ever. "Pshaw! what a silly girl I am!" said she. "It was a nightmare. That's all." She raised her hands to her face. It was hot and dripping. "Father prescribed too large a dose of blankets. No wonder I had this horrid dream." But, notwithstanding the presence of the light, and the absence of all noise, such as would be caused by the murderer in leaving the room and going down stairs, the impression of this tragic vision upon her mind was not to be dismissed with a "Pshaw!" Pet would have derived much relief from opening the door and looking in, and seeing, with her own waking eyes, that her father was alive, at his usual seat in the corner. She placed her hand upon the latch. But then she remembered how her father had laughed at her, two or three times before, when she was a younger girl, and not so wise as now, and had rushed into his room screaming with fright from a nightmare. She prided herself on having outgrown childish fears. She also remembered that her father had told her, two days before, that he was engaged in the most difficult mathematical calculations, day and night, and, kissing her, had playfully said that she must not disturb him. "He is thinking over his problems now," thought little Pet. "Dear father! I _do_ wish he would give up that hateful machine. It will be the death of him. But he said I must not disturb him, and I will not. Mr. Wilkeson must have gone home a long time ago; and dear father is thinking, as he calls it, with his hand on his forehead, in the old corner. Let me take one little peep through the keyhole, and go to bed again." Pet stooped, and looked through the keyhole. Within her range were the chair where Marcus Wilkeson had sat that evening, and the nail where--with bachelor-like precision--he always hung his hat. Neither Marcus Wilkeson nor his hat were in their accustomed, places. "What silly things these dreams are!" thought little Pet. The keyhole did not command the corner of the room where the machine stood, and where the inventor pondered and toiled; but Pet felt as certain that he was there, coaxing thoughts out of his pale brow with that habitual caress of the hand, as if she had seen him. "Good night, dear father," she whispered, softly. "May Heaven watch over your labors, and keep you from all harm."