“What is it?” asked Rattleton, in awe—“what can it be?”
“Give it up,” confessed Frank. “Let’s find out. Come on.”
They moved toward the light, and soon they found themselves looking down into a round chamber of the great cavern from a height of many feet.
What they saw filled them with inexpressible astonishment.
The place was lighted with electric lamps, and down there in the chamber was a steam engine and a small electric dynamo.
The engine was running steadily, and the dynamo hummed with a sound about which there now was nothing uncanny.
Near the engine, watching it with interest, was the girl of the golden hair.
Harry clutched Frank’s arm.
“There she is!” he panted. “We have found her at last!”
They stood in silence for several moments, watching the girl, who looked very pretty beneath the light of the electric lamps.