but I'll be mor'n glad when
it's safe done."

With this Tom Evert went on towards the slope; but Derrick stayed behind
with the mine boss to learn what he might of the operation of placing
the timber supports of a mine roof.

He had not watched this work long when a distant muffled sound,
something like that of a blast, and yet plainly not produced by an
explosion, reached their ears. Although not loud, it was an ominous,
awe-inspiring sound; and Derrick would have taken to his heels and made
for the bottom of the slope had not his pride kept him where he was.

To his surprise the mine boss, who had listened intently to the sound
while it lasted, seemed to regard it as a most natural occurrence.
Giving a few directions to his men, he turned to the boy, saying, "Come,
Derrick, let us go and see what is the trouble back in there."

For an instant Derrick looked at him to see if he were really in
earnest; then realizing that he was, he followed him without a word.

When they reached Paul Evert's door, the mine boss said, "It's
quitting-time, Paul; so get out of this as quickly as you can. It is
just possible that we may all have to run," he explained to Derrick,
after Paul had obeyed his order and left them, "and in that case all
those using crutches will need a good start."

Of course this did not greatly reassure Derrick, and he would gladly
have followed his friend Paul had not duty commanded him to remain with
his friend the mine boss.

Finally they reached the place where, less than an hour before, Derrick
had been helping to "rob" the old heading; and here they discovered the
cause of the sound they had heard. The roof above that entire set of
workings, so far as they could judge, had fallen; and had not Tom Evert
decided to quit work when he did, it is probable that no trace would
ever have been found of him or those with him.

Derrick felt deeply thankful that his life had been thus preserved, as
he walked thoughtfully beside the mine boss away from the scene of
disaster.

"How invariably Nature asserts herself in the end, and defies the puny
efforts of man to alter her ways," said Mr. Jones to himself, musingly.
Then to his companion he said, "I brought you with me to try you,
Derrick. I hated to come myself, for I did not know what might be going
on, after all these squeezes and movements of the mine. It had to be
done, though, and it seemed a good opportunity for testing your courage,
so I asked you