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 shy 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 efforts of the
caretaker were at last bringing results. The sounds also aided them
in direction, and in a short time they stood at the shaft on the