Looking up they beheld the cause of this trouble. The last German destroyer had come almost upon them, and the British gunners, evidently not seeing the little boat, were continuing their fire at the enemy. The lads were in imminent danger of being struck by a British shell. The German launched a torpedo, and it went skimming right by the little boat in which the boys sat. "Quick!" cried Jack. "We must get out of here or one of those things will hit us." The men bent to their oars; but they were not quick enough. Struck by some missile, the boat suddenly sank beneath them, and the boys found themselves in the water, swimming. And still they were between the two fighting ships. Looking over his shoulder, Jack could make out the Sylph, and calling to Frank to follow him, he struck out in that direction. They swain rapidly, but seemed to make little progress. Lord Hastings, standing on the bridge of the Sylph, discovered the two forms in the water. A second boat was hastily launched, and put off toward them. When it was within a few yards of them a fragment of a shell struck it and it also disappeared. It went to the bottom with all on board, nor did any of its ill-fated victims come to the surface again. The two lads, now clinging to pieces of wreckage, continued at the mercy of the sea, and also in constant danger of being struck by an exploding shell, while they swam slowly toward the Sylph. In one final despairing, attempt to sink the Undaunted, the last German destroyer launched another torpedo. By a wonderful maneuver the British cruiser again avoided the projectile, which sped on through the water. Swimming, the boys could plainly follow its flight. As the Undaunted swung out of the way to avoid it they could see that the missile had a clear path to the Sylph. With a gasp the boys saw the torpedo speed toward the little scout cruiser. Lord Hastings had not seen the projectile launched--because a view of the German ship had been obstructed until the Undaunted swung out of the way--and no effort was made to avoid it. The torpedo crashed into the Sylph on the water line, and the explosion which followed must have torn through all the various compartments to the engine room, for there was a second loud explosion, steam leaped up on all sides of the Sylph, and when it had cleared away, there was no Sylph to be seen. The little scout cruiser had disappeared; vanished, had been destroyed. Of Lord Hastings and the other officers and men, the lads could see nothing. For a moment the boys were unable to speak, so astounded were they at the suddenness of this terrible disaster. "Great Scott!" gasped Frank at last. "Do you realize what has happened?" Jack was more calm. "Perfectly," he replied faintly, with a sob in his voice. "The Sylph has gone, and with her Lord Hastings and all on board--all our friends, the only ones we have in the world." The two boys unconsciously swam closer together.