"There must be some opening beneath the brass lining," he said.
"Take it to the window, and perhaps you'll be able to see something more," suggested Sam.
Dick did as advised, and, with his brothers gathered close beside him, worked over the money casket for fully quarter of an hour.
"It seems to click, and that's all," he said disappointedly. "If I could only——Oh!"
Dick stopped short. His finger had run across the lining in a certain way. There were three clicks in rapid succession, and on the instant one of the brass plates of the box flew back, revealing a tiny compartment behind it, not over a quarter of an inch in depth.
"No diamonds there," said Tom, his face falling. "Full of emptiness."
"No, here is a sheet of parchment," returned Dick, pulling it forth. "A map!" he added, as he unfolded it. "Well, I never!"
"Never what?" came from Tom and Sam.
"Unless I am mistaken, this is like the map that was on that table in the cave, only this is much smaller."
"That's interesting, too," said Tom.