"lean over carefully, while I drop this
match down."

As he struck the match, and then cast it from him it went downward
twenty, thirty, forty feet before it was extinguished.

"Ugh!" shuddered Bob, "why, it must be all of a thousand feet down to
the bottom, Frank! It scares me just to think of the narrow escape I
had."

"Well, I reckon it's all of one hundred feet," replied Frank; "and
that's enough to settle a fellow. But let's lie back here, and get our
breath a bit before going on up. The cave can't be far off now, if
what Joe said is so."

Both of the boys were panting after their unusual exertion, and Bob was
glad of a chance to rest for even a brief time. Besides, another burst
of thunder was starting in, and he fancied that it was louder than any
that had gone before; just as if they might be drawing closer to the
place from whence all this clamor came.

The cave that Spanish Joe had found and entered--could it have anything
to do with the mystery of the mountain? Frank seemed to think so, and
was bent upon ascertaining the facts.

"Listen to that, Frank?" shouted the Kentucky lad in the ear of his
mate, while the racket was at its height. "I can hear rocks dropping
all around, just like the one did where Joe was grabbed by the leg. Do
you think this always happens when the old mountain breaks loose; or is
this an extra big celebration?"

"I was trying to get that myself, Bob," admitted Frank; "but we can
only guess at it, because you see, nobody's ever been up here when the
thunder was rocking the whole range, and so we don't know. But,
honest, now, I'm of the opinion this happens only once in a great
while; else the mountain would have been racked to pieces long ago."

"And just to think, we had the nerve to come here at a time when it was
bound to do its worst," said Bob.

"Glad of it," Frank immediately returned. "It gives us a better chance
to learn a few things worth while. I always did like to be in where
the roping was fastest. Are you feeling better, Bob?"

"Oh! yes, I reckon I'm all right now," returned the other, rising.

"Ready to go on, then?" continued Frank.

"Try me, that's all. If I turn tail and run, don't ever speak to me
again," came the steady, but not boastful, answer.

"Good boy! All right, let's be off again; and be mighty careful how
you move. There may be more of those drops lying around loose. And
next time you mightn't be so lucky about grabbing a spur