The two of them were already on their knees, crouching below the rail of the vessel, and at once crept forward till they were level with the cabin; then, peering in, Geoff made out the figures of the three officers below, still in the same positions they had occupied before--the fat, bald-headed man, undoubtedly the senior of the party, nodding on the divan, while the officer at the head of the table still smoked and still prattled to his neighbour. Then he nudged Philip, and, passing behind the skylight, stood at his full height, and stepped quickly along the deck towards the sentry, who still marched to and fro, to and fro, apparently without hearing his approach, as he paid no attention to it. Indeed, Geoff was within five yards of him before the man suddenly turned his head and noticed his coming, and just as suddenly came to a halt and grounded his weapon. "Who goes there?" he challenged, in quite low tones, and it was evident that he was not in the least concerned by Geoff's appearance. Indeed, he had been anticipating the exit of one officer, at least, from the cabin, where he knew that his betters were smoking and chatting, and no doubt the figure now coming towards him was one of them. Nor was Geoff in the least disconcerted; for, thanks to the dress he wore, to the fez which was perched on his head, and to his command of the language, he felt no doubt of being able to deceive the fellow. "Officer, going rounds," he answered to the challenge. "Dismiss, my man, and go to your quarters; the Commander feels that there is no need of a sentry while we lie right out here in the river, and, that being the case, there is no need for you to spoil a night's rest. Get down with you!" The man shouldered his rifle at once and turned as if to obey the order, and then, of a sudden, he swung round again, as if an idea had struck him, or as if he were suspicious. Indeed, there was something which had attracted his attention, a dark, shadowy something which his eyes, hitherto seemingly so useless to him, had discovered following the officer who had just given him the order. It was the dark shadow of a man, creeping along close to the rail of the ship, as if prepared to spring upon the back of the officer. "Beware!" he cried. "There is a man behind you, one who sneaks along in the shadows." That shadow launched itself from beside the rail while the man was shifting his rifle from his left to his right hand, and something flew through the air and hit the sentry so heavily in the face that he stumbled backwards. Then the officer who had given him the order was on the unfortunate man like a whirlwind, and the shadow beside him. "I've got my hand over his mouth," gasped Philip. "To the side with him; now heave!"