The sky grew darker, and every now and then a big roller entirely filled the mouth of the cavern, blinding them with spray. Having spent its fury, these great waves retired with a concussion that was deafening, dragging the canoe with fearful velocity toward the mouth of the cave by its suction. At such times they only saved themselves from being swept out to sea by grasping the hanging curtain of creepers and vines. Anai and his companion baled the canoe with a big shell, but the boys felt that their position was an awkward and even a dangerous one.

Another great wave burst, sealing up the cave as if it was an air-tight compartment, and making the waters of the cavern boil and seethe furiously. The pressure of air caused by the sudden rush of water affected the boys’ ears as if they had been suddenly placed in a caisson.

“This is terrible,” cried Jack.

“Something will have to be done,” said Billy. “We can’t last in here much longer.”

“Are we in danger, Anai?” asked Jack.

“We in very bad fix; but we getee out all right,” the Kanaka assured him, stopping his bailing.

“They’ve got some plan in their head,” decided Jack, and sat down in the bottom of the cranky, frail canoe to see what the next move was to be. It was a startling one. The two youths seized their paddles and then, as the next wave receded, they shot out of the mouth of the cave like a bomb from a mortar, before either Jack or Billy could guess their intention or stop what seemed sheer madness on the Kanakas’ part, and placed all their lives in grave danger. Outside they found themselves in the teeth of a howling gale. Spray blinded them, flying over them in sheets.

Nothing more was said, nothing seen. The air was darkened with flying spume. It seemed impossible that the canoe could live a minute.

CHAPTER XIII.—ON THE REEF.