There was no answer, but the reverberations of his own voice that came back to him seemed to show that the cave extended inward to a considerable depth.
"Hello!" he shouted again. "If there's any one in there, come out! We're friends and won't hurt you."
Again there was no answer.
"Doesn't seem to be sociably inclined," muttered Allen grimly.
"I guess there's nobody there," said Ruth. "Let's go back to the others, Allen. We've spent too much time already on this foolish notion of mine."
"It wasn't foolish at all," protested Drew. "As a matter of fact it may prove to be of the greatest importance. We ought to sift the matter to the bottom. If there's anybody on this island we don't know about, it ought to be our first business to find out. I think I'll take a peep into this mysterious cave."
He made a step forward, but Ruth's hand tightened on his arm and he stopped.
"Do you think you'd better risk it, Allen?" she asked. "How do you know what may be in there. Suppose—suppose——"
"Suppose what?" he asked with a whimsical smile.
"Suppose anything should happen to you?" she half whispered.