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."
Quickly, yet with hardly a swirl to denote her position, the submarine sank to the bed of the Sea of Marmora. Ten minutes later the dull thud of the steamer's paddles announced the fact that she was passing almost over her unsuspected enemy.
"We'll have another squint at her," decided the skipper. "It will be fairly safe to do so, since the Turks will be fully occupied with the visit of the vessel."
As soon as the periscope showed a foot above the water the Lieutenant-Commander took a lengthy survey. Then he turned to Crosthwaite, who was the only other officer standing by the bowl of the periscope.
"What do you make of that?" he asked.
Dick looked. The steamer was now berthed at the head of the pier, on which stood a Turkish lieutenant and the file of sun-helmeted soldiers, all with rifles and fixed bayonets. Passing up the gangway were several men dressed in naval uniforms, while at their heels came more Ottoman soldiers.
"Our men!" exclaimed Dick.