"Mighty strange," murmured Bob.

"There's some reason for it," put in Dave. "As sure as you live, it's a signal."

"But to whom?"

"Gee! I don't know. It's a mystery I'd give a lot to solve."

The Ramblers kept their eyes eagerly glued to the one link which still bound them to civilization, and breathed a sigh of regret as it began to slowly fade from view. At length but a tiny glimmer remained, and finally night blotted this out.

"It's gone," breathed Sam. "Old Neil Prescott is a jolly good fellow, and—great Scott—say! Am I awake or dreaming? Pinch me, somebody—quick!—What's that?"

Sam excitedly raised his voice to a shout, and sprang to his feet, while the others, with wild exclamations, followed.

"What in the world is it?" cried Bob Somers.

A light was springing into view on the opposite shore, apparently on the jutting point.

With throbbing hearts, the three watched it grow. For a moment, not a word was spoken. It seemed so unreal, so extraordinary, that they almost doubted their eyes.