e fewer twists and turns in this level than on the one
below it," Tommy explained, "and I guess we can find our way out readily
enough. If we don't," he went on, "I shall be obliged to eat a ton or
two of coal to keep from starving to death."

"Serves you right!" declared Will. "You had no business getting up in
the middle of the night and wandering off into the mine!"

"What did you do?" demanded Tommy.

"We waited until morning, and then enlisted the services of the
caretaker," replied Will. "So far as I can remember, this is about the
nine hundredth relief expedition we've been out on in search of you
boys!"

"Seems to me," Tommy chuckled, "that you're the lads that were in need
of the relief expedition! We found you boxed up in a chamber in a boat."

"But we wouldn't have been in any such mess if we hadn't started out to
look you up!" George declared.

"We should have been back before you got out of bed this morning, if
some one hadn't cut our string," replied Sandy. "We had a cinch on
getting out, but some geezer led us a fool chase by cutting our cord and
steering us around in a circle."

"Did you see any one?" asked Will.

"Not a soul!" was the reply. "But there's some one in here, just the
same. We heard the call of the Wolf Patrol a long time ago and we've
heard it several times since."

"What do you mean by some one cutting your string?" asked George.

"Why," replied Sandy, "we tied the loose end of a ball of twine to one
of the shaft timbers and unwound the ball as we moved along, expecting
to follow it back when we wanted to get out."

"How do you know some one cut it?" asked Will.

"Perhaps you broke it," George suggested.

Sandy took a piece of the cord from his pocket and passed it over to
George with a sly chuckle.

"See if you can break that!" he said.

George tried his best to break the string, but it remained firm under
all his strength.

The boys now fell into a discussion of the ways and means of getting out
of the mine.

"I believe," Sandy exclaimed, "that if we follow the current of air
which the rising water is forcing out of this old shaft, we will come to
the entrance. As you all know, a current of air takes the shortest way
to any given point, and this one ought to blow straight toward the
shaft."

"Great head, that, little boy!" laughed Tommy.

After proceeding some distance the steady thud, thud of the pumping
machinery was heard, and the boys understood that the eff