hought. How do you account for it? Can you have
made a mistake in regard to the plans?"

Derrick's heart sank within him as he remembered the weak spot in his
tracing; but he answered, "I don't think so, sir; though it does look as
if something was wrong."

Here conversation was interrupted by the difficulties of the road, for
they had reached the mass of fallen debris that blocked Job Taskar's way
a little later.

As they crawled on hands and knees over the obstruction, the mine boss
said, hoarsely, and with great difficulty, "Hurry, boy! there's gas
enough here to kill us if we breathe it many minutes. If we had naked
lights instead of safeties we'd be blown into eternity."

After they had safely passed this danger he said, "I hope with all my
heart that those fellows won't come that way looking for us; there's
sure to be an explosion if they do. I don't believe they will, though,"
he added, after a moment's reflection; "they're too old hands to expose
themselves needlessly to the fire-damp."

They had again waded through the icy water, which the mine boss said he
must have drawn off before it increased so as to be dangerous, and were
well along towards the opening into the break, when the muffled sound of
the explosion reached their ears.

"There's trouble back there!" exclaimed Mr. Jones, as he relighted their
lamps, which the rush of air had extinguished, "and I'm afraid that
somebody has got hurt. You go on out, Derrick, and I'll go back and see.
No, I won't, either. I can get there as quickly, and do more good, by
going round outside and down the slope. Come, let us run."

In a few minutes they had reached the bottom of the break, climbed the
rickety ladder, and once more they stood in safety beneath the starlit
sky of the outer world.

"Eight o'clock," said Mr. Jones, looking at his watch. "We've been in
there three hours, Derrick, and seen some pretty lively times. What I
can't understand, though, is how we got in on that lower level. Never
mind now; we must run, for I'm anxious about that explosion."

The news of the disaster in the mine had already reached the surface,
but nobody knew exactly how or where it had taken place. A crowd of
people, including many women and children, was rapidly gathering about
the mouth of the slope, anxious to learn tidings of those dear to them
who were down in the mine with the night shift.

The voice of the mine boss calling out that the explosion had occurred
in a