An awful roaring was audible, sending a shiver through the Ark. At the bottom of the mass of smoke, through which gleams of fire were seen to shoot as they drew nearer, appeared the huge conical form of the mountain, whose dark bulk still rose nearly seven thousand feet above the sea that covered the great, beautiful, and historic island beneath it. They had got within about twenty miles of the base of the mountain, when a shout was heard by those on the bridge, and Cosmo and the captain, looking for its source, saw the _Jules Verne_, risen to the surface a little to starboard, and De Beauxchamps excitedly signaling to them. They just made out the words, "Sheer off!" when the Ark, with a groaning sound, took ground, and they were almost precipitated over the rail of the bridge. "Aground again, by ----!" exclaimed Captain Arms, instantly signaling all astern. "I told you not to go fooling round a volcano." "This beats me!" cried Cosmo Versál. "I wonder if the island has begun to rise." "More likely the sea has begun to fall," growled Captain Arms. "Do you know where we are?" asked Cosmo. "We can't be anywhere but on the top of Monte Lauro," replied the captain. "But that's only three thousand feet high." "It's exactly three thousand two hundred and thirty feet," said the captain. "I haven't navigated the old Mediterranean a hundred times for nothing." "But even then we should have near seven hundred and fifty feet to spare, allowing for the draft of the Ark, and a slight subsidence of the water." "Well, you haven't allowed enough, that's plain," said the captain. "But it's impossible that the flood can have subsided more than seven hundred feet already." "I don't care how impossible it is--here we are! We're stuck on a mountain-top, and if we don't leave our bones on it I'm a porpoise." By this time the _Jules Verne_ was alongside, and De Beauxchamps shouted up: "I was running twenty feet under water, keeping along with the Ark, when my light suddenly revealed the mountain ahead. I hurried up and tried to warn you, but it was too late." "Can't you go down and see where we're fast?" asked Cosmo. "Certainly; that's just what I was about to propose," replied the Frenchman, and immediately the submersible disappeared. After a long time, during which Cosmo succeeded in allaying the fears of his passengers, the submersible reappeared, and De Beauxchamps made his report. He said that the Ark was fast near the bow on a bed of shelly limestone. He thought that by using the utmost force of the _Jules Verne_, whose engines were very powerful, in pushing the Ark, combined with the backing of her own engines, she might be got off. "Hurry up, then, and get to work," cried Captain Arms. "This flood is on the ebb, and a few hours more will find us stuck here like a ray with his saw in a whale's back."