"One!" The speaker was Jack Templeton, an English youth and first officer of the British submarine D-16, Lord Hastings, commander. Frank Chadwick, an American lad about the same age as Jack, the second officer of the under-sea fighter, laid his hand upon his friend's arm. "Let me take a look," he said. Jack relinquished to his chum his place at the periscope, and the latter peered into the instrument long and earnestly. Into the periscope-which protruded slightly above the surface of the water while the submarine was still submerged-came the vision of a sinking warship, and the sight, enlarged by powerful binoculars, was apparent to Frank's eyes. "She's done for, all right," he said quietly, turning away at length. "Pretty good shooting, I should say."