Passing through the first room, Lenoir conducted them to a sort of out-house beyond.
Here they came upon the first surprise.
He opened a door which apparently shut in a cupboard, and this, to their intense astonishment, revealed a flight of stone steps which seemingly led into the very bowels of the earth.
"Hallo!" exclaimed Jack; "why, what's this?"
"I thought I should astonish you, now," said Lenoir, with his same calm smile.
"What is this place?"
"There is a whole series of caves below these, apparently natural formations. The only way I can account for them myself is that at some time or other some experimental mining operations have gone on there. Would you like to go down and see the place?"
"With pleasure," returned Jack, eagerly.
"Allow me to lead the way."
When they had descended a few steps, Jack half repented.