Frank and Jack approached the foot of the periscope, where they stood awaiting developments. Outside a sudden storm swept the water of the North Sea in angry waves. The water lifted up the little vessel with the regular motion of a high-running sea. All was pitch dark. The fact that men were hurrying about on deck, was only shown by the somber figures who now and then passed in front of a single lantern. From out the engine room, already under water, arose the pound of heavy pounding and the weird crackling of the engines, as they were tried out. Jack glanced at his watch. It was 10:30. Suddenly there came a shrill whistle from the little bridge of the submarine, standing high above the vessel, and covered with heavy canvass. The officer in command, Captain Von Cromp himself, dressed hi heavy oilskins, raised a hand, the signal to go ahead. A short, sharp signal to the engine room, a loud whirr of the motor, and the X-9 was speeding ahead. On both sides of the ship long waves formed, shimmering with light foam in the blackness of the sea. The X-9 moved westerly--toward the still unsuspecting battleship. The heavens were covered with clouds. Not a star was visible. It was impossible to see more than a few feet away from the strange craft. Captain Von Cromp, with his experienced eye, tried in vain to penetrate through this wall of solid blackness. The wind kicked up the sea and the bridge was entirely flooded with water. There was hot a sound to be heard, save the heavy droning of the motor and the swish of the water passing along the sides. Suddenly, in the near distance, loomed up a great gray bulk, swinging high above the submarine upon the water. It was the British battleship. And now submarine X-9 had been discovered. A heavy boom rang out, but the little craft was not damaged. Another signal came to the ears of the two boys. Men rushed upon deck and soon the submarine was prepared for action. The flagpole was taken down. Part of the bridge was folded together and securely fastened. The periscope was fixed at its proper height. Then the entrance through the combined bridge and conning tower was hermetically sealed. A moment more and the tanks were opened, telling the lads that the submarine was about to submerge. The gasoline motors stopped their endless song. From now on electricity would drive the vessel forward. Near Frank and Jack, at the periscope, stood Lieutenant Stein, looking at the British ship. The sailors took their stations near the torpedoes. The interior of the boat was now lighted with two small electric bulbs. They made the darkness visible, but gave no light outside. Everywhere was the stale smell of oil. The boys found it impossible to speak to each other because of the noise of the engine and the water. The heat was oppressive.