About mid-day Prince's Island hove in sight. The submarine, having taken her bearings, dived to avoid a fleet of feluccas evidently engaged in fishing; for only upon the supposedly impregnable Sea of Marmora did the Turkish fishermen--all of them too old to be called upon to serve in the Ottoman navy--dare to ply their business. The fear of Russian destroyers had long before swept the Black Sea clear of all Turkish merchantmen and small craft. "May as well have a look round before we dive," declared Huxtable, as the submarine reached her desired temporary resting-place. "The sun's right behind us, and the glare will effectually prevent anyone on shore from spotting our periscope. I'm rather curious to know what that square tower is, and whether it is armed." Two hundred yards only from the lurking submarine the shore rose with comparative steepness from the sea. According to the chart there was a depth of eight fathoms up to within twenty yards of the south side of the island, and owing to a faint southerly current, caused by the discharge of the pent-up waters of the Bosphorus into the wide expanse of the Sea of Marmora, the water in the vicinity of the group of islands was thick, and tinged with a sandy deposit, rendering it well adapted for purposes of submarine concealment. Dead ahead was a small creek, on the eastern side of which was an old stone tower, about thirty feet in height and capped by a loopholed parapet. On this flew the Ottoman Crescent, while the sun glinted upon the bayonet of a befezzed sentry as he leisurely paced the ground in front of the low gateway. At the water's edge below the tower was a rough wooden pier of less than twenty yards in length. It was in a very decrepit condition, for several of the piles were raking at alarming angles, while the single handrail in several places had broken away from its supports. Even as the officers of the submarine kept the tower and its vicinity under observation the sentry began to show signs of alacrity. He shouted something--although no sound reached the confined space of the submerged vessel--and pointed sea-wards. Instantly Huxtable grasped the wheel of the diving gear, at the same time ordering the men to "stand by". But it was not on account of the submarine that the Turkish sentry gave the alarm, for other soldiers, to the number of about a dozen, appeared and pointed seawards, but not in the direction of the lurking craft. One of them entered the tower, and presently hoisted a signal from the stumpy flagstaff. Training the periscope astern, the Lieutenant-Commander discovered the reason for the excitement ashore. A small paddle-steamer was approaching from the direction of the Bosphorus. "A representative of the Ottoman navy," said Huxtable with a laugh. "Etiquette demands that we should not intrude, so we'll make ourselves scarce."