"McKee," said Burdoch, abruptly, "have you ever been in this mine before?"
"Yes; two years ago I was employed here for a few weeks."
"Is there any place—any secret place—besides those that we have visited where the boy could be confined?"
"Yes," answered McKee, with a sudden thought, "there is a vault not now used, rather apart from the rest of the mine, where he might be concealed."
"Can you guide me there?" asked Burdoch, eagerly.
"Yes, I think so."
"Then do so in mercy's name!"
McKee's memory served him well. He led the way to the side excavation. It was shut off from the rest of the mine by a wooden door. That door was locked.
"This is the place," said Burdoch. "Now to find out if Gerald is here!"
He struck with his heavy jack-knife on the door, and then waited.