"I think we will rise now," said the inventor; "you boys had better hold on, for we may go up pretty quick." "I hope we _do_ go up," muttered Tubby, rather nervously. The stout youth was not particularly in love with the dark depths in which they were navigating. In fact, all the lads, though they did not admit it, experienced a longing for daylight. It was an awe-inspiring feeling--too awe-inspiring to be comfortable--to be in the depths of the ocean where no keel had ever before plowed. Mr. Barr remounted to the conning tower. A minute later a renewal of the swishing sound told that the pumps were emptying the tanks at the rate of a thousand gallons a minute. The submarine could be felt to leap upward toward the surface. The boys held on for dear life, exchanging rather alarmed glances. All at once the pace slackened, and the swishing sound ceased. Mr. Barr had decided that the pace was too swift and had cut off the pumps. "Well, thank goodness that's over!" gasped Donald. "At the rate we were going up we'd have bounced clean out of the sea." "I guess we're all right now," remarked Merritt. The words had hardly left his lips when there came a jar and a bump that shook the submarine in her every frame and rivet. The boys were thrown from their feet and hurled about the cabin. At the same instant the engines stopped and the submarine began to back, but slowly, like a stricken animal. "We've rammed something!" "We're sinking!" These and a hundred other exclamations came from the alarmed boys. Mr. Barr poked his head down into the cabin. "Are you all right below?" he asked. "Yes; but what has happened?" "Have we been badly damaged?" "Are we sinking?" The above questions were all shouted at once in the tense excitement. Barton, his face white as ashes, came out of his engine room. "What did we hit?" he demanded in a frightened voice. "I don't know; but we struck something, possibly a sunken wreck, a hard blow," was the inventor's reply. Although his face was deadly pale, his voice was without a tremor as he spoke. "We must make an examination at once," he went on. "Andrews, Higgins, and Ross," addressing the three sailors who had appeared from forward, "make an examination forward at once and see if any of the plates have started. If you find a suspicion of a leak report to me at once." The sailors, trained in naval discipline, saluted, and hastened off on their errand. "If we are leaking, what are we to do?" demanded Rob. "Meet death as bravely as we can," was the reply in steady tones; "submarines carry no boats and we must go to the bottom unless we can find some way to stop the leak." Small wonder that the boys were stricken aghast. Barton, the machinist, flung himself face downward on a couch and began whimpering. The inventor looked at the man with contempt. "Stand by your engines, Barton," he commanded sternly; "the first man to shirk his duty in this emergency will have to settle with me."