understand, the cowboys all keep away from Thunder Mountain as much as they can. They're worse than the Injuns about it, because while the reds say that is the voice of Manitou talking, these fellows just up and declare the mountain is haunted. Lots of 'em couldn't be hired to spend a night on the side of that big uplift."

"But Frank, we don't believe in any such thing, do we?" pursued Bob, as if he had begun to suspect what all this talk was leading up to, and wished to draw his chum on.

"We sure don't, and that's a fact," declared Frank. "Twice, now, one of our boys has made out that he saw a ghost, but both times I managed to turn the laugh on him. All the same, if you offered a lump sum for any fellow to go and camp out half-way up the side of Thunder Mountain for a week, I don't believe he could be found, not at Circle Ranch, anyhow."

"I've seen the same kind of men myself; and the coons around our old Kentucky home always carried a foot of a graveyard rabbit, shot in the full of the moon, as a sure talisman against ghosts. I've seen many a rabbit's foot. No use talking to any of them; it's in the blood and can't be cured. But about that offering a sum for any fellow to go and camp on the side of that old fraud of a haunted mountain, if you happen to hear about such a snap you might just think of me, Frank."

The other saddle boy smiled broadly. He believed he knew Bob pretty well by this time, and could no longer doubt what the Kentucky lad was hinting at.

"Say, look here, would you take me up if I proposed something right now?" asked Frank, his face filled with sudden animation.

"If you mean that we try and beat Peg Grant at his own game, and learn what the secret of Thunder Mountain is, I say yes!" answered Bob, steadily.

"Shake on that!" he exclaimed. "I'm just primed for something that's out of the common run; and what could be finer than such a game? I saw Billy Dixon in town; and we can send back word to father that we've gone off for a big gallop; so he won't worry if we don't turn up for a few days. Is it a go, Bob?"

"Count on me," replied the other. "I don't know how it is, Frank; but it strikes me that I'd like to cut in on that boaster in this thing. If we managed to find out what makes that fearful booming in the mountain, and told about it before he got a chance to blow his horn, he'd feel cheap, wouldn't he?"

"He sure would, now," Frank said. "And when you look at it, he just the same as gave us the challenge direct, because he hinted that we didn't have the nerve to attempt such a big thing as this. Bob, we'll call it a go! Wonder what Peg will say when he runs across us out there in that lonely place? Wow! I reckon he'll be some mad."

"Let him," remarked Bob, carelessly. "He has no claim on Thunder Mountain; has he? And we want to call his bluff, if it was one. So just make up your mind we're in for a new experience. It may pan out a heap of fun for us. And it will be worth while if we can settle the question that has been giving these superstitious cowmen the creeps all these years."

"Then let's get through with our business, send word by Billy, though not telling what we've got in the wind, and then pick up a few things we might need on a trip like this. After that we can drop out of town, and take our time heading for the mountain; because I think I'd like Peg to get there first, so that he couldn't say we'd stolen his thunder."

Half an hour later the saddle boys, having finished their business, and sent the Circle ranch cowboy galloping homeward bearing the message to Mr. Haywood, were moving slowly through the main street of the town, heading toward a store where they could pick up a couple of blankets, a simple cooking outfit, and some of the substantials in the way of bacon, coffee and the like, when they came upon a scene that instantly attracted their attention.

It was a terrified cry that reached their ears at first, and caused both boys to pull in their horses. Glancing in the direction whence the sound of distress seemed to spring, they saw a small Mexican girl struggling with an over-grown fellow, garbed in the customary range habit, even to the "chaps" of leather covering his trousers.

Both Frank and Bob jumped from their saddles, for the little affair was taking place in the courtyard of an inn that fronted on the street. Whether the brute was simply playing the bully, and trying to kiss the girl; or meant to strike her for getting in his way, Bob Archer did not stop to inquire.

His warm Kentucky blood on fire, he made a swoop for the fellow, and managed to give him a tremendous blow that toppled him over in a heap.

"Lie there, you coward!" he exclaimed.

And then, as the fellow whom he had knocked down struggled to his knees, to stare up at him, Bob discovered, not a little to his surprise, and satisfaction as well, that he was looking into a familiar face.

It was Peg Grant!

CHAPTER II

THE STRANGE ACTIONS OF DOMINO

"Well, I declare!" exclaimed Frank; which remark showed how much surprised he was to recognize the youth whom his chum had sent to the ground.

"What do you mean by hitting me like that?" snarled the rich man's son, as he managed to scramble to his feet again, though he seemed a bit "groggy," and one of his eyes was already turning dark, as if it had come in violent contact with a stone when he struck the ground.

"What do you mean, hurting that poor little Mexican girl?" demanded Bob, who stood on his guard, as though he might not be averse to trying conclusions with the bully, if so be the other felt like seeking satisfaction for his upset.

"She sassed me when I ordered her to get out of my way, that's what she did;" declared Peg, wrathfully, "and I'd look nice now, wouldn't I, letting a little greaser kid talk back to me? So I was just giving her a good shaking when you broke in. Guess you didn't know who you were hitting when you did that, Bob Archer!"

"Perhaps I didn't," replied the Kentucky lad, calmly; "though that wouldn't have made any particular difference. Any cur who would lay his hands on a child like that ought to get knocked down every time. I'd do it again if you gave me the chance!"

Peg stared at him. Perhaps he had never been treated in this manner before. All his life his acquaintances had truckled to him on account of the great wealth of his father, and the liberal way he himself, as a boy, rewarded those who were allowed the privilege of being his cronies or mates.

"You—would, eh?" he gasped, as if hardly daring to believe his ears. "Even if you knew it was Peg Grant you'd treat me that way; would you? I'll remember that! I'm not the one to forget in a hurry. Some day, perhaps, you'll wish you'd never tried to play the hero part, and hit me when my back was turned. I've got a good notion to teach you a lesson right now; that's what!"

"All right," remarked Bob, coolly. "Suppose you begin. I was never in a better humor for trouble. Somehow I seemed to just know we'd hit it up sooner or later if our trails crossed. I give you my word, my friend here won't put a finger on you, if so be you get the better of the row; will you Frank?"

"I should say not," declared the lad, instantly, adding: "and unless I miss my guess there won't be any need of it, either."

"Are you coming on, Peg?" asked the Kentucky lad, temptingly.

From under his drooping eyebrows Peg observed how easily the other had assumed a position of self-defense. Somehow Peg did not fancy the athletic build of his antagonist; for, while Bob was rather slender, he had the marks of one accustomed to exercise; possessing at least ordinary ability to take care of himself.

"It'll keep, and be all the better for the delay," Peg grumbled, as he clenched one fist furiously, and used the other hand to feel of his injured optic. "Besides, I don't feel fit to fight right now, with this bunged-up