only about five hundred feet deep. If I remember correctly, there are
three levels; one at three hundred feet; one at four, and one at
five."

"And which level is this?" asked Tommy. "Why, we're on the bottom,
ain't we?"

"Of course," laughed Tommy. "I ought to have known that!"

"Well come along if you want to see the mine!" urged Sandy. "All we
have to do is to push our searchlights ahead and walk down the
gangway. We'll come to something worth seeing after a while."

As the boys advanced they found the gangway considerably cluttered
with "gob," or refuse, and the air was none of the best.

"I wish we could set the air shaft working," suggested Sandy.

"Well, we can't!" Tommy answered with a scornful shrug of his
shoulders. "We can't set the whole works going in order to give us a
midnight view of the Labyrinth mine. What gets me is how are we going
to find our way back? There seem to be a good many passages here."

"I've got that fixed all right!" Sandy exclaimed.

As the lad spoke he took a ball of strong string from his pocket and
tied one end to the cage which lay at the bottom of the shaft.

"Now we can go anywhere we please," he chuckled, "and when we want to
return, all we've got to do is to follow the string."