his companion, and also drew him back. It was
none too soon, it seemed. As if the release of Spanish Joe might have
been the signal for the groaning mountain to once again take up its
strange action, they felt the quiver with which all the performances.
seemed to begin. Then the grumble commenced, rapidly advancing into a
fearful stage, until Bob could feel himself trembling violently because
the rocks under him were moving.

"There she comes!" cried Frank.

His words were drowned in a deafening crash close by. Had Peg Grant
been there he must have believed that the top of the mountain had blown
off, and that fire and boiling lava would immediately begin to pour
down the sides. But Bob had not forgotten about that swaying rock.
And he understood that it had fallen with a crash just at the spot
where the three of them stood a minute before.

"What a narrow escape!" exclaimed Frank, after the clamor had in some
measure died away again.

"Oh! I should say it was," echoed Bob, feeling quite weak as he
realized what must have happened to them had they not gotten away in
time.

"How about your leg, Joe; can you walk?" asked Frank, turning to the
cowman, who was scrambling to his feet close by.

"Seems like I can, Senor Frank. But it was a close call for Spanish
Joe. Only for you coming, where would I be right now? Let us get away
from here!" exclaimed the man, limping around as he tried his crippled
limb.

"You are free to go, if you want, Joe," remarked Frank; "but Bob and
myself mean to stick it out. We came here to learn the cause of all
this racket, and we'll do it, or know the reason why."

"Excuse me, _companero_, I know when I have had enough. This mountain
is surely bewitched. There must be an evil spirit living inside. Do I
not know it? And even the door is guarded by demons that spring at a
man and tear him. My clothes, once so handsome, Senors, are torn into
tatters, just because Joe, he was fool enough to step into that black
opening above!"

Frank started as he heard the Mexican say this. It seemed to him that
possibly here was a clue worth following up.

"Tell us what you mean, Joe," he asked, quickly. "What black opening
did you try to enter; and what happened to you, _amigo_? We have done
you a service, saved your life, perhaps. In return, tell us this."

"It is little enough, Senor Frank. Up above, not more than seventy
feet from here, lies a hole in the ground. I was lookin