Mr. Livingston knew that both boys were excellent swimmers. He told them they might go ahead, but to make the dip a brief one.
Willie posted himself at the entranceway to the tunnel, promising that if he saw anyone approaching on the trail, he would whistle twice.
Jack and War stripped to their shorts and dived from the rocky ledge deep into the cooling waters. Down, down, down, they went into the dark depths, enjoying the descent.
Finally, growing short of air, Jack pulled up his head and came to the surface, gulping air.
War broke water close by, and swam in a circle with a smooth, easy crawl stroke. Above, on the rock ledge, Ken and Mr. Livingston watched somewhat anxiously.
“Make it snappy,” Ken advised. “This isn’t the Y pool, you know.”
Jack swam a few minutes longer, then pulled himself to a low rock shelf only a few feet above the lake surface. From this position, he dived again, taking it at a long slant.
His body scraped rock, and he realized with a shock that he had barely missed diving head foremost into a projecting shelf which had not been visible from above.
Still under water, his right hand touched a hard, small object lying on the projection. Involuntarily, his fingers closed upon it. Then, in need of air, he surfaced again.
Pulling himself out onto the wide shelf below Ken and Mr. Livingston, he opened his fist to see what it was he had found.