"A howler. Allers does when the wind backs up that way into the sou'east. 'Sides, if so be ye air still sot on findin' out what makes that thunder up this ways, p'raps ye'll have the chanct to look into the same afore long, Peg."
"Oh! was that what I felt just now?" cried the boy, scrambling to his knees. "It seemed to me the old mountain was trembling just like I did once, when I had the ague. And Nick, I believe you're more'n half right, because I sure heard a low grumble just then, like far-away thunder. I wish I hadn't been such a fool as to come up here. Never get me doing such a silly thing again as long as I live. Listen! It's coming again, Nick, and louder than before. Don't you feel how the ground shivers? Perhaps there's going to be a terrible landslip right now! Do you think so, Nick?"
Frank and Bob, crouching close by, had also felt that quiver under them. It gave the saddle boys a queer feeling. When the solid earth moves it always affects human kind and animals in a way to induce fear; because of the confidence they put in the stability of the ground.
And then there arose gradually but with increasing force a deep terrible rumble.
Thunder Mountain was speaking!
CHAPTER XIV
A CALL FOR HELP
"Oh! what shall we do, Nick?" cried Peg.
His voice was now quivering with fear. Evidently whatever little courage the fellow possessed, or the grit which had caused him to start upon this mission of attempting to discover the cause of the mystery connected with Thunder Mountain, had suddenly disappeared.