Frank turned to the cipher again. For a few minutes he worked industriously. Little by little, the complete message took shape on the sheet of paper.

At last he sat back with a sigh of satisfaction.

“All serene! The cipher is solved.”

“Read it.”

Frank picked up the paper and read aloud:

CABIN ISLAND CHIMNEY LEFT FRONT

NINE FEET HIGH.

Chet groaned with disappointment.

“And what good does that do?”

“What good does it do? Don’t you understand? This message refers to the chimney right in this very cabin. All we have to do now is examine a part of the chimney on the left hand side, in front, nine feet from the floor.”