While he was thus musing, he fancied he heard the lock tried. A chill ran through his frame, and, grasping the heavy weapon with which chance had provided him, prepared to strike down the first person who should enter the cell. After listening attentively for a short time without drawing breath, he became convinced that his apprehensions were groundless, and, greatly relieved, sat down upon the chair to rest himself and prepare for further efforts. Acquainted with every part of the jail, Jack well knew that his only chance of effecting an escape must be by the roof. To reach it would be a most difficult undertaking. Still it was possible, and the difficulty was only a fresh incitement. The mere enumeration of the obstacles that existed would have deterred any spirit less daring than Sheppard's from even hazarding the attempt. Independently of other risks, and of the chance of breaking his neck in the descent, he was aware that to reach the leads he should have to break open six of the strongest doors of the prison. Armed, however, with the implement he had so fortunately obtained, he did not despair of success. "My name will only be remembered as that of a robber," he mused; "but it shall be remembered as that of a bold one: and this night's achievement, if it does nothing else, shall prevent me from being classed with the common herd of depredators." Roused by this reflection, filled with the deepest anxiety for his mother, and burning to be avenged upon Jonathan Wild, he grasped the iron bar, which, when he sat down, he had laid upon his knees, and stepped quickly across the room. In doing so, he had to clamber up the immense heap of bricks and rubbish which now littered the floor, amounting almost to a car-load, and reaching up nearly to the top of the chimney-piece. "Austin will stare," thought Jack, "when he comes here in the morning. It will cost them something to repair their stronghold, and take them more time to build it up again than I have taken to pull it down." Before proceeding with his task, he considered whether it would be possible to barricade the door; but, reflecting that the bar would be an indispensable assistant in his further efforts, he abandoned the idea, and determined to rely implicitly on that good fortune which had hitherto attended him on similar occasions. Having once more got into the chimney, he climbed to a level with the ward above, and recommenced operations as vigorously as before. He was now aided with a powerful implement, with which he soon contrived to make a hole in the wall. "Every brick I take out," cried Jack, as fresh rubbish clattered down the chimney, "brings me nearer my mother." CHAPTER XVIII. The Red Room.