A fearful roar, a mighty wave which almost swept Mervyn from the deck, an avalanche of falling fragments, then the whole thing was over. As the last of the _debris_ plunged into the seething water, and before the scientist had recovered from the shock, his comrades, awakened by the uproar, darted out on deck. “Whatever has happened?” Garth gasped, gazing in amazement at Mervyn’s ashen-white face, and then at the rapidly receding ice-cliffs. Somehow Mervyn stammered through his explanation. “Great Scott!” Seymour cried, as the scientist finished, “if the cable hadn’t parted, the _Seal_ would have been crushed like an egg-shell!” “It was a close call,” Haverly broke in. “I guess we must ha’ struck a fairly healthy current, to snap the cable like that. However, all’s well as ends right side up.” He grasped the wheel as he spoke, and the engineer, who had hurried on deck with his friends at the alarm, went below once more to his engines. A moment later the _Seal_ was leaping forward, with her engines running at twenty-five knots. For some little time Garth stood watching the wall of foam flung up by the _Seal’s_ sharp prow as she raced over the waters of the Polar Sea. A vessel to be proud of was she, and none were more thankful than her inventor for her marvellous escape. At length he turned towards the stairhead. “I think I’ll go down and prepare a bit of grub,” he said. “I dare say you fellows can manage a feed?” “Rather,” Seymour returned, and at the word Garth left the turret. Some moments later Haverly noticed a decided increase in the speed of the vessel. “Say!” he growled down the tube, “what speed have you got on?” “Twenty-five,” came Wilson’s answer. “I guess we’re doing more like fifty,” returned the Yankee. “Ease her off ten knots and stand by.” For a time the way of the _Seal_ slackened, but not for long. Within ten minutes she was sweeping on as fast as before. Again Silas grasped the tube, and there was a note of irritation in his voice as he called sharply, “Half speed astern!” There came a clank from the engine-room as Wilson flung over the levers; then a jarring, grinding crash, that shook the vessel from stem to stern, and the purr of the engines ceased. With an exclamation of annoyance, Mervyn left the turret, and went below. As he disappeared a cry broke from Seymour. “Land ho!” Far away on the horizon a dark, cloud-like shadow rose out of the sea, growing in size each moment as the vessel raced on. Glass in hand, Seymour sprang to the door; but though he exerted all his huge strength, it defied his efforts to open it. “Lock the wheel for a second, Silas,” he said, “and give me a hand with this door; it’s got jammed somehow.” “I guess the wheel don’t need any locking,” retorted the Yankee, as he loosed the spokes. “What do you mean?” Seymour asked. “The steerin’ gear’s got jammed, too,” returned Silas, with a grim smile, and he applied himself to assist Seymour with the door.