These thoughts raced through Tempest’s brain as the pair glided along for the first ten minutes. When he considered it safe to turn they headed straight for the _Firefly_, and then the most hazardous part of the journey began. It was now more necessary than ever to exercise caution, for though the dark form of the Kanaka was almost invisible, Tempest’s face gleamed in the moonlight occasionally. He swam under water as much as possible, coming to the surface only to take breath, and moving slowly so that scarcely a ripple marked their progress. It was eery work; and though Tempest was a brave man, a chill ran down his spine more than once when he reflected how probable it was that a bullet would be their greeting. One careless splash would be almost certain to attract the attention of the sentry on the _Firefly_, and Tempest did not like to think what an easy target his face would make. The _Nautilus_ lay anchored near the _Firefly_, and their object was to reach her safely first if possible. The suspense of the last stretch was terrible. The Kanaka now disappeared under the water for long distances, and showed little more than his mouth and nose when he came up again; but Tempest had not the marvelous skill of the South Sea Islanders. While completely submerged he progressed with powerful strokes, and he did not venture to take breath until his lungs seemed to be bursting. He was never more thankful for anything in his life than when they reached the side of the _Nautilus_. Hanging on there, and taking a much needed rest, he listened intently before daring to make the next move. Not a sound reached his ears. With infinite caution he paddled round the prow and, grasping the cable of his boat, raised his head a trifle. This nearly ended in his undoing. At the stern of the _Firefly_ one of Flagg’s Kanakas was squatting, his head resting on his hand. Across his knees was balanced the rifle which had hitherto kept the invading force at bay. This much Tempest took in at one lightning glance, when his hand slipped on the wet cable, and the Kanaka spun round as he heard the slight splash Tempest could not avoid making. Like a stone the swimmer sank and made for shelter behind the _Nautilus_, with a dreadful fear that the lookout had seen him. The Kanaka, however, after staring with suspicion in the direction of the noise, came to the conclusion it must have been made by a fish, and settled down again to his long, monotonous vigil. Tempest waited impatiently for a while, and then ventured to take another peep. The sentry did not appear to be particularly alert. On the contrary, it almost looked at that distance as though his head was nodding sleepily. Tempest held up a warning finger to Jim, motioned him to remain where he was, and glided through the water nearer to the _Firefly_. With infinite caution he placed his hands on the side of the boat and raised himself partly out of the water, until his face was within a few feet of the sentry.