"Let's hope the Turks will have no necessity to exercise their powers of discernment," said Huxtable. "In any case I want to do a little more damage before we're out of action. But," he added cheerfully, "I have a presentiment that we'll fetch back in safety." Several hours passed in tedious suspense. Numerous steam vessels sped overhead or within hearing distance, for the thud, thud of their engines and the noise of the revolutions of their propellers could be distinctly heard. "You'd better turn in," suggested Huxtable to Dick. "There's nothing doing, and you must be awfully tired." "I feel a bit sleepy," admitted Crosthwaite; "but don't you think you ought to have forty winks, sir?" "I suppose I'd feel all the better if I did," admitted the Lieutenant-Commander. "Devereux can take charge. He's had his watch below." Enjoining the Sub-lieutenant of the submarine to call him at the first suspicion of danger, Huxtable pulled off his boots and rolled, just as he was, into his bunk, while Dick was soon fast asleep in the bed recently occupied by young Devereux. It seemed as if he had not dozed for more than ten minutes when Dick was awakened by the purr of the submarine's electric motors. He started up. The officer's cabin was ablaze with light. Devereux, with a bundle of charts under his arm, was making his way along the narrow gangway between the double rows of bunks. "Hello, old man!" he exclaimed. "Awake, eh?" "What's the time?" asked Dick drowsily. Devereux consulted his watch. "Twenty-three minutes past two," he announced. "Never!" ejaculated Crosthwaite incredulously. "Surely I haven't----" "Yes, you have," interrupted Devereux with a laugh. "Seven and three-quarter hours of solid sleep! Sorry I disturbed you." "You didn't," declared Dick. "It was the engines." "We're on the move again," explained his companion. "We're following a small paddle-boat. Huxtable fancies it's the one that piloted us here. He may be right--he generally is. If so, it's a rare slice of luck. Look at young Farnworth. Submarine life apparently suits him, for he's doing his level best to sleep the clock round." Just then a bell clanged. The Lieutenant-Commander's voice could be heard ordering the ballast tanks to be blown. "I must be off," exclaimed Devereux. "It's action stations. Something's up." Dick was out of his bunk in a trice, but before he gained the door he heard the order being given to charge both tubes. The submarine was about to attack yet another victim. CHAPTER XVII Within Sight of Constantinople Instinctively Dick Crosthwaite made his way to the conning-tower, where Lieutenant-Commander Huxtable was standing by the bowl of the periscope. The latter took no notice of his involuntary guest; his whole attention was centred upon the ill-defined patch of light that, momentarily growing brighter, showed that the submarine was on the point of rising to launch her fatal missiles.