CHAPTER XIII

A SIGNAL FOR HELP


"Didn't scare you, did I?" said Mr. Harley, walking into the circle
and smiling at the perplexed faces.

"We didn't hear you coming," answered Bobby. "Did you row over?"

"Yes, I came over to tell your mother that your father couldn't
get back till the afternoon boat," Mr. Harley explained. "Your
mother wanted to know if I'd come and fetch you."

"Does she want us?" asked Meg quickly. "Oh! What was that?"

"Thunder," answered Mr. Harley, shortly. "Your mother sent you two
umbrellas, but I don't think we'd better start now; the storm is
'most ready to break. Guess you were having such a good time you
never heard the rumbling."

It was true. The children had never glanced up, or they would have
seen the great white clouds that, mounting higher and higher,
gradually darkened and then shut out the sun. They would have
heard the angry mutterings of thunder and seen the sharp streaks
of lightning, but the game of hunting for treasure had completely
absorbed them.