Some demurred to this, but the Rover boys could, not be held back, and on they went, with Aleck with them. Soon Randolph Rover hobbled after them, leaving Cujo and the college students to remain on the watch.
The cave proved to be a large affair, running all of half a mile under the mountain. There were numerous holes in the roof, through which the sun shone down, making the use of torches unnecessary. To one side was a deep and swiftly flowing stream, coming from the waterfall Cujo had mentioned, and disappearing under the rocks near the entrance to the cavern.
"Gold, true enough!" shouted Dick, as he gazed on the walls of the cave. "Am I not right, Uncle Randolph?"
"You are, Dick; this is a regular cave of gold, and no mistake.
No wonder King Susko wanted to keep us away!"
Soon the waterfall was gained. It was a fascinating scene to watch the sparkling sheet as it thundered downward a distance of fully a hundred feet. At the bottom was a pool where the water was lashed into a milky foam which went swirling round and round.
"Look! Look! The ghost!" suddenly cried Sam, and pointed into the falling water. "Oh, Uncle Randolph, did you ever see anything like it?" and he gave a shiver.
"There are no such things as ghosts, Sam," replied his uncle. "I see nothing."
"Stand here and look," answered Sam, and his uncle did as requested. Presently from out of the mist came the form of a man—the likeness of Randolph Rover himself!
"It is nothing but an optical illusion, Sam, such as are produced by some magicians on the theater stage. The sun comes down through yonder hole and reflects your image on the wet rock, which in turn reflects the form on the sheet of water."
"Gracious! And that must be the ghost the natives believe in," answered Sam. "I'm glad you explained it. I can tell you I was startled."