back to the camp spot to make a new discovery that puzzled him. On
the ground near where they had slept were Hiram's coat, vest, shoes
and cap.

"Why, I can't understand this at all," mused the young aviator.
"Hiram couldn't have done much in the way of climbing up, he appears
to be nowhere within hail, and he is not given to play tricks."

Dave did not wait to eat anything. He was really concerned about
his comrade. He got a long tree branch, stripped it, and went along
the side of the cairn, poking in and out among the dense dumps of
shrubbery.

"Hello," he exclaimed suddenly, as disturbing some vines he saw an
opening, and not twenty feet away a natural rocky tunnel, "daylight,
and the waves of the lake. I think I understand now."

Dave penetrated the passage. As he came out at the other end, he
found he faced a rock-strewn stretch of sand. The waves of the lake
lapped this. In the distance he could make out Anseton, and nearer
still, about a mile distant, the main shore.

The shore he was on terminated in a ridge of rocks that ran far out
into the water. Dave wondered if the exploring spirit had moved
Hiram to attempt an entire circle about the island.

"He went away in swimming trim," thought Dave, "so that may be so.
I'll go out on that ledge of rocks and explore a little myself."

"Hello, Dave Dashaway!" sang out an exultant voice, just as Dave was