would ever be able to do more than sit up in a chair. And now—" She stopped abruptly as Garth himself plunged in suddenly from the living-room and caught Joan's hand.
"The tide's zackly right for the sea-caverns!" he cried. "She's finished with the dishes, hasn't she, Mudder?"
"I'll let her go," smiled Mrs. Pemberley.
"So he writes!" thought Joan, as she went slowly after Garth into the blazing sunlight. Everything was explained now—the names of the boats, the books in the living-room, all that had puzzled her. She stepped out at the door with a much fuller understanding of the life at Silver Shoal.
Garth stopped where tumbled rocks made a rough breakwater at the northern end of the ledge. Here were deep irregular pockets, walled with stone and half-covered by leaning-slabs. The water sucked in and out between the stones with a hollow sound.
"The best way to do," explained Garth, "is to lie down, like this, and put your head under the rock, so that it shuts out the light."
"With your head in the water?" inquired Joan somewhat dubiously.
"Oh, no," said Garth; "sometimes a wave
