His companion handed the candle to him, and took from his pocket a big jack-knife--larger, if anything, than the weapon which had been left under the window of the little farm-house at Five Forks. He ran the large blade up and down the two long, straight cracks, tapping the stonework here and there with the butt of the handle afterward. Finally, after numerous experiments, he found the trick--a bolt to be pushed down by a blade inserted not straight but obliquely--and a thick, iron-bound door, faced with masonry, but with an oaken lining, swung open, heavily and unevenly, upon some concealed pivots. The O’Mahony took the light once more, thrust it forward to make sure of his footing, and then stepped over the newly-discovered threshold, Jerry close at his heels. They pushed their way along a narrow and evil-smelling passage, so low that they were forced to bend almost double. Suddenly, after traversing this for a long distance, their path was blocked by another door, somewhat smaller than the other. This gave forth a hollow sound when tested by blows. “It ain’t very thick,” said The O’Mahony. “I’ll put my shoulder against it. I guess I can bust her open.” The resistance was even less than he had anticipated. One energetic shove sufficed; the door flew back with a swift splintering of rotten wood. The O’Mahony went stumbling sidelong into the darkness as the door gave way. At the moment a strange, rumbling sound was heard at some remote height above them, and then a crash nearer at hand, the thundering reverberation of which rang with loud echoes through the vault-like passage. The concussion almost put out the candle, and Jerry noted that the hand which he instinctively put out to shield the flame was trembling. “Show a light in here, can’t ye?” called out The O’Mahony from the black obscurity beyond the broken door. “Sounds as if the hull darned castle ’d been blown down over our heads.” Jerry timorously advanced, candle well out in front of him. Its small radiance served dimly to disclose what seemed to be a large chamber, or even hall, high-roofed and spacious. Its floor of stone flags was covered with dry mold. The walls were smoothed over with a gray coat of plastering, whole patches of which had here and there fallen, and more of which tumbled even now as they looked. They saw that this plastering had been decorated by zigzag, saw-toothed lines in three or four colors, now dulled and in places scarcely discernible. The room was irregularly shaped. At its narrower end was a big, roughly built fireplace, on the hearth of which lay ashes and some charred bits of wood, covered, like the stone itself, by a dry film of mold. The O’Mahony held the candle under the flue. The way in which the flame swayed and pointed itself showed that the chimney was open.