Ellerton realised that he was entering into a new phase of his existence. He regretted it, for, beyond his natural anxiety concerning his parents, he had grown to love the isolated life on McKay's Island.

Then, should Blight's story prove to be correct, Ellerton felt sure that Mr. McKay's action was the only course permissible. The little colony was to fight for its existence, and the more remote the scene of hostilities the better chance they had of securing the sole proprietorship of the island.

Hist! A succession of faint sounds like those of a man stealthily swimming caused Ellerton to sit bolt upright, grasp his rifle, and peer intently through the darkness.

There was no mistake about it. It was some object heading directly for the yawl, its track being marked by a faint blur of phosphorescence.

Visions of bloodthirsty savages, swimming, knife in mouth, to surprise the crew of the little craft, filled Ellerton with alarm. He raised his rifle, released the safety catch, and took aim at the mysterious intruder.

"Andy," he whispered, but his friend was too deep in slumber to be awakened by a whisper.

"I'll wait till he's close alongside," muttered Ellerton, fingering the trigger.

At that moment there was a perceptible jar alongside the boat, followed by a prolonged grating sound, as if a piece of sandpaper were slowly drawn over a rough surface. Then, with a swirl and a succession of phosphorescent splashes, the object vanished.

The sound had roused Andy.

"What's up?" he exclaimed, springing into the cockpit.