At this moment Mr. Jepson made a sharp hit with a stick he had found on the deck, at the boards which covered the hatch. A hideous yell of rage and pain followed the blow. Dory could understand, without an explanation, that one of the fellows below had thrust his fingers through one of the openings between the boards, and that the machinist had rapped them with his weapon. "That was Mack," said the sentinel, who had learned the sound of his voice by this time. "He will have a lame hand." Then a lively sound of snapping boards came up from the hold; and it was clear that the desperate prisoners were tearing down one of the bunks to obtain the material of which they were built, for use in the next operation, whatever it might be. The machinist divined the purpose to which the pieces were to be applied. He looked about him for the means of meeting the new attempt. There was an axe in the waist, which had been used in cutting up fuel for the cook-stove in the cabin. The machinist took possession of it, and rushed back to his post. At every opening between the boards, a stick was thrust through, and the prisoners were trying to pry apart the pieces that covered the hatch. With a blow of the axe, the instructor broke off every end that came through. It was lively work for him for a few minutes; but not a single lever of the half-dozen used, could be made to accomplish any thing. This attempt was a failure, like those which had preceded it. A silence of some minutes followed, and then Dory heard the voices of the party in the cabin; but they were more quiet than they had been at any time before. Doubtless, things were beginning to look more serious to them. The boards at the hatch had been tested; and, when the prisoners left the hold, the machinist joined the skipper on the quarter-deck. The party below did not seem to be doing any thing; but presently there was another demonstration at the hatchway, and Mr. Jepson rushed forward to repel any attack in that quarter. The sticks were brought into use again, and the machinist was kept busy breaking off the ends of them for some time. Dory watched him with interest until he heard a strange noise behind him. When he turned to see what it was, he discovered Mack in the act of coming over the taffrail to the deck. He had only time to take a turn in the tiller-rope he had held in his hand to assist him in holding the helm, before the robber rushed upon him. "I have got at you at last, and we will settle it here and now!" exclaimed Mack, as he threw himself upon the skipper. Dory had expected to see a revolver staring him out of countenance, when he discovered the approach of his assailant, and he had put his hand on his own weapon. But when Mack sprang upon him, he was ready for him. It was a short struggle, though a very violent one; and Dory held his man by the throat till the machinist came to his aid. Together they tied his arms behind him, and rolled him into the scuppers.