eet 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."

"Quite an idea!" laughed Tommy.

The boys proceeded along the gangway, walking between the rails of the
tramway by means of which the coal was delivered at the bottom of the
shaft. The experience was a novel one to them. The dark walls of the
passage, the echoes which came from the counter gangways, the monotonous
dripping of water as it seeped through seams and crevices in the rock,
all gave a weird and uncanny expression to the place.

After walking for some distance the boys came to a level which showed
several inches of water.

"We can't wade through that!" Tommy declared.

"Well," Sandy suggested, "if we go back a little ways, we can follow a
cross heading and get into the mine by another way."

The boys followed this plan, and, after winding about several
half-loaded cars which had been left on the tramway, found themselves in
a large chamber from which numerous benches were cut.

"Where does all this gas come from?" asked Tommy stopping short and
putting a hand to his nose.

"There must be a blower somewhere," Sandy explained.

"What's a blower?" demanded Tommy. "What does it look like, and does it
always smell like this?"

"It doesn't look like anything!" replied Sandy. "It's composed of
natural