Marcus stepped back, and said, “Now let it cease.”

Pet saw her father snatch something that looked like a club, from some part of the machine.

“This is my answer,” he said, and precipitated himself with fresh fury upon Marcus.

The younger man had expected the attack, and braced himself for it.  He caught the inventor by the arm that held the club, or other weapon.  They wrestled for its possession—­the inventor with frenzy in every feature, Marcus with fixed determination, and silently.

The weapon was now aloft—­now below—­now shifted in the twinkling of an eye to the right, and now to the left.  At one time the inventor seemed to be on the point of securing it; at another, Marcus.  Suddenly Pet saw it whirl like a shillelah above her father’s head, with a strange noise like the quick winding of a clock.  Then she heard a dull sound, as of striking a board with a brick, and—­she saw her father fall to the floor.  At the same moment, the light in the room went out, and all was darkness.

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.”