As Jack climbed into the boat there was a great plunge into the water which caused the light craft to rock again and the spray to fly.
"That settles him!" gasped Percival, and then he dropped his weapon and drew Jack into the boat, where he promptly sank limp and helpless under the thwarts, all his strength having seemingly left him.
"All right, Jack?" asked Percival.
"Yes, but get away," answered Jack feebly.
Percival was not slow to obey the injunction.
Seizing the oars, he quickly backed water and then turned the head of the boat toward the entrance of the cave, whence he shortly saw the light streaming in as he pulled a quick, powerful stroke.
"I'm glad that's over!" he said with a sigh of deep relief as he neared the opening. "No more exploring queer places like this again!"
When he was outside the cave he rested on his oars and said:
"You are all right again, Jack?"
"Yes," said Jack, getting up and seating himself on a thwart, "but I don't want another such an experience. I feel as if all the blood had been drawn out of me by that horrible thing in there."