There was still water in the lower levels of the mine, but it was slowly disappearing through the sump, and the indications were that it would be dry by morning. The boys listened intently for some evidence of occupancy as they moved up and down the shaft, but all was still.

"This would be a good place to tell a ghost story," Tommy chuckled as they moved back to their room on the first level.

"There's about a million stories now, entitled "The Ghost of the Mine!" declared Sandy. "Perhaps however," he went on, "one more wouldn't hurt."

"If I see a ghost tonight," declared Tommy, "it'll be in my dreams!"

Sandy and Tommy were sound asleep on their cots as soon as supper was over, and Will and George were getting ready to retire when the soft patter of a light footstep sounded in the vicinity of the shaft.

"Rats must be thick in the mine!" suggested George.

"Rats nothing!" declared Will. "Those two youngsters are prowling about in order to see what we are up to!"

As he spoke the boy arose, turned off the electric light and stepped out into the passage.

CHAPTER XII

A MIDNIGHT ROBBER