IX. THE CAPTURE OF THE SUBMERGED VESSEL 99 X. THE SECRET KEY TO THE BOMB FUSE 110 XI. OPERATING THE SUBMARINE WITH A CAPTIVE CREW 120 XII. THE DEATH BLOW TO THE SUBMARINE 130 XIII. THE RESCUE IN THE CHANNEL 142 XIV. TEN HOURS IN THE DANGER ZONE 151 XV. A FRIGHTFUL MINE EXPLOSION 161 LIST OF ILLUSTRATIONS _An Explosion Followed That Seemed to Tear Everything to Pieces_ _Frontispiece_ PAGE _The Points of the Compass_ 27 _The Submarine Decoy_ 30 _Map Showing the Scene of the Wanderings of the Boys_ 43 _The Steel Nets_ 73 _The Entangled Submarine_ 95 _The Periscope_ 137 _The Conning Tower. All That Could Be Seen of the Submarine_ 148 _A Contact Mine_ 156 THE BOY VOLUNTEERS WITH THE SUBMARINE FLEET CHAPTER I THE OMINOUS WARNING ON SHIPBOARD "Submarine two points to starboard, sir!" shouted a voice. Instantly there was confusion; the captain sprang from the end of the bridge to the board behind the quartermaster and pushed a lever to the right. "Ralph, come out quickly; the second officer has just shouted to the captain that a submarine is in sight," said Alfred, as he rushed into the reading room where Ralph was deeply engrossed in a book. Ralph needed no second warning. Together with a dozen or more, who were in the room, he sprang to the door, and followed Alfred, who was now nearing the bridge. "Can you see it?" asked Ralph excitedly. "No; but they are pointing to the right; it seems as though we are turning around," responded Alfred. "So we are," said Ralph. "There! what is that?" shouted Ralph, as he followed the direction pointed out by the second officer. The captain gave another wrench to the wheel, and the ship straightened out on its course. All eyes were now directed to a point to the right, and astern, for the boat had described a half circle. "Wait till I get the glasses," said Alfred, as he dived for the main companionway, and slid down the railing. He was back in record time, followed by his father and mother, accompanied by Ralph's mother. Needless to say all were agitated, for they had been told on the morning of sailing that the trip might be a dangerous one, and it was only urgent business necessity that compelled Mr. Elton to take the risk.