“Is it safe? I have heard that some old mines are filled with gas and foul air.”

“This is perfectly safe—I’ve been into it a dozen times,” answered Darry, confidently.

After a walk of an hour, Frank and his companion reached the side of the mountain where the cave-in had occurred, and Darry showed how the mine could be entered.

“You are certain of the way—we don’t want to get lost, you know.”

“Are you afraid?” asked Darry, with a light laugh.

“No, but I want to be sure of what I am doing.”

“I know just what I am doing.”

“Then lead the way,” said Frank.

His companion had brought with him a regular miner’s lamp and this they lit, and walked into the mine.

The sight to be seen was certainly a novel one, and they went in deeper and deeper, while Darry explained how the mine had been worked.