"Looks easy, doesn't it, after we've run across a clue?" admitted Bob, laughing softly. "You remember what they said about discovering America, after Columbus did it. But supposing this thing does turn out to be true; how's it going to affect our little business, Frank? Oh! say, I wonder if that crowd can have anything to do with the rumbling of the mountain?"

Frank laughed heartily at the suggestion.

"Well," he remarked, "they're a pretty tough lot, all right; but even such a bad bunch could hardly get enough hot air together to make a mountain shake and groan like that. Besides, don't you see, Bob, they must have been out yonder, riding this way with their stolen horses, when that little circus came off."

"But one thing is sure," the other went on, sturdily; "they don't seem to take any stock in that notion about a volcano, because, as we saw, they headed straight for Thunder Mountain. That gives it away; they're so used to the row that they don't pay any attention to it any longer."

"Correct!" echoed Frank, as though his mind was made up.

"Do we need to hold the horses down any longer?" asked Bob, who could feel that Domino was becoming very restless under his enforced silence.

"I reckon not," replied the other, at the same time taking the blanket from Buckskin's head; whereupon the animal, recognizing this as a sign to rise, quickly gained his feet and shook himself.

"It's back to the blankets again for another nap," remarked Bob, when he, too, had seen his animal regain an upright position. "Wonder what's next on the programme for us. Twice, now, we've been waked up; and I don't know whether it's really worth while trying to get any more sleep to-night. It isn't a great ways from dawn, is it, Frank?"

The other cast a quick look up at the stars. Accustomed to reading these heavenly sign posts of the night, he was able, from their positions, to give a pretty fair guess as to the hour; just as the sun served him in place of a watch during the day.

"Three hours yet to dawn, Bob; no use staying up all that time," he said, presently. "We expect to be on the move again at peep of day; because, after what's happened, it'll be wise for us to get off the level here before broad daylight comes along. There might be curious eyes on the watch up yonder, on Thunder Mountain; and that, you see, would just spell trouble for our crowd."

"Whew! things are thickening, for a fact!" exclaimed Bob.

"I was only thinking," Frank continued, "whether we ought to try and get word back to the ranch about our discovery. If they knew Mendoza and his rustlers were hiding somewhere about this place they'd comb the whole mountain range so they could run him to earth. He's been the pest of the border too long now, and something's just got to be done to chase him back where he belongs, south of the Rio Grande."

"But you don't want to go back just yet, do you, Frank?" asked Bob, uneasily.

"I'm ready to do what you say, though I'd like to stay," came the prompt answer.

"Then I say, let's stick it out," declared Bob, with animation. "It might turn out to be a false alarm, after all; and we'd feel pretty cheap to bring all the boys along, and then not be able to show 'em any game. No, I say it'll be time enough to go after 'em, when we make dead sure!"

"That settles it, then," remarked Frank, with a little laugh, as though pleased to learn that his saddle chum looked at the matter in such a sensible light.

This time, after they had lain down in their blankets, there was no further alarm. Frank, from long habits of early rising on the range, awakened just as the first faint streaks of dawn began to show in the eastern horizon.

It required but a touch to arouse Bob; and saddling up, with packs in place, the boys soon left the scene of their night bivouac, heading toward the heavy growth of timber directly at the foot of the mountain.

The early morning mists concealed their movements until they had entered among the timber; when they left they were safe from any suspicious eye, should the bold Mexican rustler have posted any watcher upon the side of the mountain.

Again did the saddle boys build a small fire in a hole, over which they proceeded to cook their breakfast; while the horses cropped the grass near by, secured by the ever useful lariats, or riatas.

"There's where this leads into a big gully," remarked Bob, later on, pointing as he spoke to where the ground became broken.

"Yes," Frank went on, thoughtfully, "and the chances are ten to one that it changes into a regular canyon, where the water rushes down whenever they have one of those gushers, or cloud bursts, that come along once in a while around here. Now, I wonder if those riders hit it up this way?"

He jumped to his feet as he said this. Passing back and forth, Frank seemed to be examining the ground, marking the stepping stones of the mountain.

"Signs aplenty around here," he remarked. "Wish old Hank was along to read 'em. I reckon I can tell what they stand for, though."

"Then they went on up that canyon, you believe?" asked Bob.

"Reckon there isn't any doubt about that part of it," chuckled Frank; "though just where that same canyon leads I can't say. P'raps it may be a short-cut across the big range here, leading to the prairie on the other side. P'raps it doesn't go anywhere, but just leads to a blind hole that I've heard prospectors call a cul de sac. Anyhow, we ought to find out, Bob."

"They knew all right," remarked the other, positively. "Wouldn't get any riders going up there in the dark, unless they were mighty familiar with every foot of the way. That's my idea, Frank."

"And I reckon it's the true one," asserted the other. "They know this place as well as I do all around old Circle Ranch."

"There's the sun coming up; and perhaps we'd better be getting a move on about now?" suggested Bob.

"Wait!"

Something in the tone which his saddle chum used caused Bob to turn his head, and look out toward the plain.

"Huh! what does that mean?" he ejaculated. "A single rider heading this way; and he seems to be leading a burro loaded with supplies. Must be a bold prospector, bound to look into the secrets of Thunder Mountain as we're bent on doing; only he hunts for gold, while we're just bent on finding things out."

"But look now," Frank said a little later, as the other came closer. "Don't you see that it's only a little Mexican boy on that bag of bones of a horse? Tell you what, Bob, he must have been sent to town for fresh supplies by some party of gold hunters located right now over the range."

"Yes, and how do we know but what this Mexican boy is hooked up with that Mendoza crowd?" asked the other, seriously. "They might send him off for grub, and such things as they happen to need. And he pays for it with money they get from selling stolen cattle and horses! Nobody would suspect him, Frank, and try to follow. I hope our horses don't give us away now. I'd like to see what that little fellow does."

The boy indeed looked weary as he drew closer, leading his tired burro, upon which a fair-sized load was strapped and roped.

"Get down, Bob," said Frank. "He hasn't glimpsed us, and, luckily enough, our horses are feeding out of sight just now. Doesn't he look sleepy and tuckered out though? See him nodding in his saddle, poor little runt! Oh! what's that moving there among those rocks just ahead?"

"Perhaps it may be one of the rustlers coming down to interview him," said Bob.

"Hist!" Frank uttered almost in his chum's ear as he craned his own neck in order to see better.

The small boy on the tired broncho, and leading the patient burro, kept on steadily advancing, apparently allowing his animal to follow its nose, as though it knew the way fairly well from having passed along it before.

"Look! look!" ejaculated Frank suddenly, jumping to his feet. "Great guns! Bob, would you see what is coming out from among those loose rocks there? A great big grizzly bear; and making straight for the pack mule, sniffing the air as if he smelled grub! There, the horse has scented him. See him rear up, will you? Oh! he's gone and done it, as sure as you live—thrown the boy over his head! And the poor burro is caught fast, with his leading rope held in a crotch of the rocks. The boy will be killed if ever he meets up with that monster! Quick! We must do something to save him, Bob, but whatever shall it be?" and Frank leaped to his feet.



CHAPTER VIII

A STARTLING DISCOVERY

The Mexican boy had apparently escaped serious injury at the time the frightened cayuse made a sudden bolt upon sighting the bear, and threw him over his head onto the rocks.

The lad was already sitting up, and rubbing his knee in a dazed way, as if not fully understanding what had happened. The pony rushed wildly away, heading up the wide gully, as though with a full knowledge of where it was going. And the poor little burro would doubtless have been only too glad of a chance to follow, if only it could break loose from the detaining rope.

Meantime the ugly monster, that had been the cause of all this commotion, was shuffling closer with each passing second, eager to strike down the burro with one savage blow from his mighty paw with its long claws, after which he could proceed to help himself to what those various packages contained.

All this Frank Haywood saw in that one glance he shot toward the scene of action. The boy was apparently directly in the path of the hungry bear. And when his pony had fled in such a panic he must have also carried off the rifle, if the boy possessed so valuable a weapon.

Thus the little fellow was at the mercy of the most feared wild beast to be found in all the territory between the Atlantic and the Pacific.

A wild inclination to hurl himself between that brute and his prospective victim surged over Frank. With but a knife, or even a revolver to back him up, such a rash act would have been little short of madness. Fortunately it was not needed.

"Let me try for him, Frank!" said a trembling voice at his side.

And then, all at once, Frank Haywood discovered his chum was crouching close by, and that he was clutching a rifle in his shaking hands. How he had managed to get hold of the weapon Frank could not even guess, because his own was a dozen feet away just then.

Now Bob Archer had certainly never before set eyes on a ferocious bear outside of the circus or museum. And doubtless that brownish-colored beast looked as big as a house to him, for he was very much excited. But he had true Kentucky pluck, and even that circumstance did not make him quail. If the monster had seemed to equal two houses, still would Bob have tried to do his duty. And just then it was to save that poor little Mexican boy.

The grizzly had advanced so rapidly that he was already almost upon the crouching boy, who stared at him as if in dire dismay, as well he might. It was not too late, even then, for the boy to have escaped, could he have understood the real situation, and that it was the food in the packs the bear craved, rather than his life; but he did not seem to realize the fact.

They had seen him fumbling about his sash, and now he drew something forth that glistened in the early morning sun. Why, the little chap had actually drawn his knife, as though that trifling bit of steel could avail anything more than the prick of a pin against that shaggy monster.

The boy was shivering as with terror, but all the same he showed himself game. Frank was amazed by the sight, and not apt to forget it in a hurry.

But by now Bob had stepped forward, uttering a sharp "hello" as he did so. His object, of course, was to attract the attention of the bear toward himself. This might cause the grizzly to change his course, and allow of a few more seconds' delay. It would also divert the attack from the helpless boy to one who was at least better armed, even though not professing to be a bear-hunter.

Frank aroused himself. He remembered that he, too, had a repeating rifle, leaning against the trunk of a tree not far off. He sprang to secure the firearm, in the belief that possibly his assistance would be needed in order to finish the dreaded animal.

However good Bob's intentions were, when he sought to draw the attention of the grizzly toward himself, they did not succeed as he had hoped. Bruin seemed to know that a feast awaited him as soon as he could clear a way to that frantic little burro with the big load. And he declined to be turned aside on any account.

Seeing this, the Kentucky boy dropped on one knee. He felt that he must find some sort of rest for his gun, since his shaking hands could hardly be expected to hold the weapon steady when it came time to pull the trigger.

Even as Frank swept up his gun he heard the weapon of his chum speak sharply. The report was instantly drowned in a tremendous roar. Looking, even as he drew back the hammer of his rifle, Frank saw that the bear had finally turned away from temptation in the way of meat and supplies. He had started to rush Bob, whom he evidently recognized as the cause of that sudden pain which had shot through his bulky body.

Bob was pumping another cartridge into the firing chamber of his repeater. He seemed cool, although perhaps only he himself knew how his heart was pounding away like mad against his ribs.

Both guns spoke together, it seemed. The grizzly gave another roar, even more furious than before. At the same time, however, he stumbled, and fell over sideways. Then he tried desperately to scramble back to his four feet, still full of fight.

Both the boys again put their guns in a firing condition. Even if tremendously excited at the moment, they seemed to remember what was necessary to do in order to accomplish this result.

But the bear was apparently unable to get up again. One of the bullets must have most luckily reached a vital point in the region of his heart. He was floundering about unevenly, while the little Mexican boy sat and stared, still gripping that ridiculously small blade in his hand.

"We got him that time, Frank!" exclaimed Bob just then, though he could hardly believe his eyes at seeing the monster growing weaker. "He's a goner, as sure as shooting! Look at him wobble! Wow! there he goes over, to make his last kick! Frank, just think of me having a hand in the killing of such royal game! A real grizzly! Oh! I can hardly believe it!"

They now approached the spot where the little Mexican boy was getting on his feet again. He was no longer white. The threatening monster had been placed where he could do no more harm; but the little chap stared uneasily at the two saddle boys. Evidently he was possessed of a new cause for alarm in the mere fact of their unexpected presence.

The burro, meanwhile, had somehow managed to effect his release from the rope that had become fast in the crevice of the rock. Still in a panic because of the wild animal odor so close at hand, the laden animal hurried off after the cayuse that had fled along the gully, heading for where Frank had declared the canyon must undoubtedly lie.

And the boy really looked very much as though he, too, would like to depart with equally scant ceremony.

"Hi! there goes the burro!" called out Bob. "Head him off, Frank; or shall I jump on my horse and try to rope him?"

To the astonishment of both the saddle chums the Mexican boy threw out a detaining hand, crying earnestly:

"Senors, all, there is no need to chase them. They know where to go, believe me, and surely I must soon overtake them. You have saved my life, Senors. Lopez, he thanks you both. Before now have I seen such a bear; but this time I was caught dreaming. He would surely have killed me if it had not been for the brave Americanos."

Frank was struck with the soft tones of the small chap, who did not look as if he could be much more than twelve years of age. His features were regular, if thin, and the big black eyes seemed to be filled with a courage beyond the ordinary. Indeed, they could not doubt this, having seen how he had drawn that small knife on finding himself confronted by the Rocky Mountain terror.

"Well, we were only too glad to have been of help to you, Lopez," Frank remarked, as he advanced with outstretched hand.

The boy looked embarrassed, as though hardly knowing what to do. It seemed to Frank that he had been staring very hard at Bob, and he wondered why. Then again he imagined that the boy must be keeping something back. This would account for the worried look on his small, pinched, but good-looking face.

But undoubtedly Lopez realized that it ill became him to decline to take the hand that had helped save his life.

"You understand that we are your friends, Lopez, don't you?" asked Frank, as he held the small palm of the Mexican in his own strong one for a moment, and looked with a puzzled expression into the big black eyes that quickly fell under his gaze.

"Oh, yes, Senor, surely you have proved it more than enough," the little fellow hastened to say; and Frank was astonished to hear what good language he used.

"You go across mountains, eh?" asked Bob, indifferently; truth to tell he was just then more interested in the size of the great grizzly that had fallen before the guns of himself and his saddle chum, than the mere fact of this stripling being entrusted with such a task as bringing supplies to prospectors, or rustlers, as the case might prove.

A flash crossed the face of the boy, just as though he saw a sudden opening whereby his presence here might be explained without entering into details.

"Oh! yes, across the range. I get supplies for prospectors in camp," he replied, with an intake of his breath, while he watched Bob narrowly, as if, somehow, he believed he had more to fear from that source than from the tawny-haired prairie lad.

"That's kind of queer, seems to me," remarked Bob, slowly, turning to again survey the boy; "for them to send so small a chap on so long a trail. I should think it was more of a man's work, toting supplies across these mountains, through the canyons. And with the chances of running foul of such dangers as bears, not to speak of rustlers."

At that Lopez drew his diminutive figure up, and tried to assume a bold look. The Spanish blood was proud, Bob could see.

"This have I done a long while, Senors, believe me," he said, calmly; "and until to-day never have I met with trouble. Had I not been so tired and sleepy, perhaps even I might have shot the bear, who knows? It would not be the first I have seen, no, nor yet the second; but the horse ran away with my gun. But Senors, I must go on after my animals; they will be waiting for me farther along."

"Then you won't wait for us?" asked Frank. "My friend, he would like to get the claws of this fellow, to remember him by. It will not take very long, Lopez."

"Thank you, Senors, but I must not delay. Perhaps you may overtake me farther along the trail. There is no more danger; and my pack burro might scrape off his load if I am not there to watch. Again I thank you, Senors."

The boy bowed to each of them in turn, just as though he might have been an actor in some old-time play. Frank believed he had never seen such remarkable grace in any half-grown lad. Generally, at that age, boys are apt to be about as clumsy as bear cubs at play. He looked after Lopez with a frown on his face.

"What's the matter, Frank?" demanded Bob, as he noticed this expression. "Are you huffed just because the independent little rascal wouldn't let us mother him? Say, look at his strut, will you? If he was heir to the throne of Alfonso he couldn't walk finer. Give me a whack between the shoulders, won't you, Frank? Perhaps I've been asleep, and dreamed all this."

"Oh, rats! Take a look at the bear, and that'll show you what's what. There, he's disappeared behind that clump of mesquite yonder," and Frank turned to look at his saddle mate with an expression of bewilderment on his face, as though he might be trying to clutch some idea that kept eluding him.

"Suppose you help me cut these awful claws off, Frank. You see I don't know the first thing about how it's done; and I think your idea about keeping 'em for trophies is just immense."

"Well, for that matter," replied Frank, "I don't know as I ever did a job like that, myself; but I've watched old Hank do it, so I reckon we'll get along."

For a few minutes they worked away in silence. Then Bob looked up to remark:

"He said it was prospectors he was taking those supplies to, didn't he; and that he'd been doing the same a long while?"

"That was about the size of it, Bob," returned his chum, thoughtfully.

"Well," Bob went on, "between you and me, Frank, I'd rather believe little Lopez was in touch with the rustlers. I mentioned that word just on purpose to see if he would turn red, or give himself away."

"And did he?" asked the other, quickly.

"Well," replied Bob, "not so you could notice; but then he seemed such a smart chap, like as not he knew how to hide his feelings. He looked frightened when we talked of wanting him to stay with us. Mark me, there's a heap of mystery bound up in that little fellow."

"He sure puzzles me, all right," remarked Frank. "Did you notice how he had a silk handkerchief bound around his head, regular Mex fashion?"

"Sure I did," laughed Bob, without glancing up, as he used his knife industriously after the fashion set by his chum. "And I also took notice that he had a fine, glossy bunch of hair under that same colored silk bandana."

"Great governor!" ejaculated Frank, suddenly.

"What's the matter—you didn't cut yourself, I hope?" demanded his comrade, uneasily, starting up.

"Shucks! no. Something just struck me, that's all," replied Frank, with an air of disgust, and a quick look up the gully where the little Mexican had last been seen.

"Oh! Is that so?" mocked Bob. "Must have hurt right bad then, to make you peep like that. Now, I reckon it might have been something about Lopez?" for he had noted that hasty glance, and the disappointed frown.

"That's just what it was, Bob," Frank continued, in an even tone. "Fact is, I just remembered who Lopez put me in mind of. Only perhaps you'll laugh when I tell you. Remember that poor little girl Peg Grant was cuffing when you knocked him down? Well, if you took that colored handkerchief off Lopez, and let his black hair fall down, I give you my word he'd be a ringer for that Mexican child!"

Bob stared as if dazed, and then the light of a great discovery dawned upon him.

"Say, Frank!" he exclaimed presently. "Honest Indian, now, I believe you've sure struck pay dirt, and that's what!"



CHAPTER IX

WHAT HAPPENED TO PEG

"Then you think the same as I do, eh, Bob?" asked the saddle boy, as if pleased.

"Well, now a heap of things seem to point that way, Frank," replied the other, slowly. "Only for the life of me I can't get it through my poor old head just why a girl like that would want to carry on in such a queer way."

"Nor me, either," laughed his chum. "That's something else for us to lie awake nights puzzling our wits over. Everything around this Thunder Mountain just seems to be plastered with mystery—who little Lopez is; what he, or she may be doing away off here in the canyons of the Rockies; and more particularly the mystery of the mountain that the reds look on as sacred; where Mendoza and his band of rustlers have gone with those stolen horses; and also who the prospectors can be that this pile of grub was meant for—it's all a blank, that's what!"

"Say, I guess that's pretty near the way it sizes up," grumbled Bob. "I don't like to run against a stone wall like this. If I was alone now, d'ye know what I'd likely be doing, Frank?"

"Well, say, perhaps I might hit close to the bull's-eye, since I've come to know you pretty well these days, Bob," replied the other. "I wouldn't be surprised one bit but what you'd go rushing after Lopez, and demand to know all about it. But Bob, I look at it in another light. That's his own private business."

"I suppose so; and I was brought up to mind my own affairs, too," said Bob.

"Wouldn't you put up a great howl now," continued Frank, "if somebody grabbed hold of you, and insisted on your giving him the whole story of your life, where you were born, what your dad did for a living, when you cut your first tooth, how much it cost your father to let you gallop around the country in the saddle with me, and all that? Say, honest now, would you knuckle down like a meek kid; or give the questioner to understand that he was poking his nose into affairs that didn't concern him one whit?"

Thereupon Bob laughed heartily.

"I give up, Frank," he admitted. "You go at a fellow, and put him in a hole as a lawyer might. We'll just let little Lopez alone, no matter whether he's girl or boy; the grub-getter of prospectors; or agent for that sly Mendoza, the cattle-rustler. And, on the whole, I reckon we've got about all the business we can attend to right now on our hands."

"That sure sounds good to me, Bob," said Frank, turning once more to get his horse, the task of securing the grizzly's claws having been completed.

Naturally enough, while the excitement was on, both horses had exhibited the greatest alarm, even though they were out of sight behind some trees. The near presence of that terrible monster had caused them to strain at their ropes, prance wildly, and try in every way possible to break loose; but those lariats had been selected with a view to wonderful strength. After the death of the grizzly the animals had gradually quieted down.

Ten minutes later, and the two saddle boys were slowly picking their way along the gully, heading upward. Frank, as one born to the country, and familiar with many of its peculiarities, amused himself by pointing out to his comrade the various positive signs that as a rule marked these strange water-courses.

"You see, Bob," he remarked, "this is really what might be called a barranca."

"Yes, I've heard you tell about them before," observed the other.

"Most of the year it's only a dry ravine, with high walls; but once in a while there happens to be a tremendous downpour of rain in the mountains, when a heavy cloud breaks against the wall above. When that comes about, this gully is going to be bank-full of roaring, rushing water; and anything caught by the flood is apt to be battered and bruised and drowned before it's swept out below."

"Whew!" observed Bob, with a shrug of the shoulders. "Let's hope then, that the next cloud-burst will have the kindness to hold off till we get out of this hole. If it caught us here, Frank, I reckon we'd just have to let our nags shift for themselves, and take to climbing the sides. And wouldn't I hate to lose Domino the worst way; even if he does give me a raft of trouble at times?"

Frank patted the satiny flank of Buckskin affectionately, as he said:

"And it would just about break me up if anything happened to this fellow, Bob. I've tried heaps of mounts, seeing that we always have hundreds on the ranch; but I never threw a leg over one I fancied like my Buckskin. Why, there are times, Bob, when the game little fellow seems next door to human to me. We understand each other right well. He knows what I'm saying now; listen to him whinny, soft-like, at me."

Possibly Bob, knowing considerable about horses himself, may have had a strong suspicion that the animal understood the touch of his young master's hand much more readily than he did spoken words; but this was a subject which he never debated with Frank. The latter had a habit of talking confidentially with his horse, and seemed satisfied to believe the animal understood.

Slowly they made their way along. Now and then Frank would dismount to examine the rocks and scanty earth that formed the trail over which they were passing.

"Always plenty of signs to tell that horses have been going along here off'n on, both ways—stacks of 'em," he announced, when perhaps an hour had elapsed since they left the scene of the encounter with the grizzly.

The ravine, or gully, which he called a barranca, had gradually changed its character. It was now more in the nature of a canyon; though there were still places where the walls, instead of towering high above their heads, sloped gradually upwards.

"Smart horses could easy climb out of here up that rise," remarked Frank, thoughtfully eyeing one of these places.

"Are you thinking that perhaps we'd better get out with our nags, while we have the chance, and leave them, while we keep up the game on foot?" asked Bob, suspecting that his chum might be considering such a move.

"Well," remarked the other, "it stands to reason that our horses aren't going to be of much use in the mountains. If we shook 'em now, we'd be able to climb almost anywhere, and peek into places we'd never be able to find as long as we stuck to our mounts. So, if you're of the same mind, Bob, we'll try and find a place where we might rope 'em out, an' take the chances of finding 'em again when we're done poking around."

"I hope then, none of the rustlers will run across them while we're away," said Bob, as he looked across a deep little pool that lay just at the foot of a very high slope; and then fastened his gaze on a peculiarly twisted cedar that seemed to cling to the bank, half way up.

"Leave that to me, my boy," returned his chum, confidently. "I'll make sure they leave no trail behind to catch the eye of a horseman riding past. Besides, we're not dead sure, you know, that the rustlers have really got a camp around these diggings. P'raps now, they just push through the canyon to get to some other point across the divide. Or it may be a favorite trail for them to carry off the cattle they rustle. In some hidden valley, you see, they can change the brands; and then openly drive the steers to a shipping station on the railroad."

"All right, then," agreed his companion, who was ready to put the utmost faith in any plan proposed by his saddle chum. "We'll keep our eyes peeled for a chance to get the horses out of this place. Here's a slope they might climb, as you say; but it looks as if they'd have to swim that pool first."

"No use trying it," remarked Frank, casting a rapid glance upward to where, at a distance of possibly a hundred feet, he could see little bushes growing on the edge of the top of the rise, which slope formed an angle of something like forty-five degrees; "sure to be better places further on, where the holding is firmer."

"And yet," remarked Bob, suddenly, "horses have made this climb only a short time ago, Frank!"

"What makes you say that?" asked the other, interested at once.

"Why, there are tracks going up slantingly, you see; and even if I am next door to a greenhorn I can tell that the marks look fresh," Bob declared, pointing.

"Say, I take a back seat, Bob," Frank remarked, laughingly. "That's the time you saw my lead, and went me one better. Sure there have been horses climbing that slope—one, two, three of 'em. And Lopez, he had only two; so it can hardly be him. I wonder now if that measly tenderfoot, Peg——"

"Look up yonder!" interrupted Bob, suddenly pointing again. "I saw the bushes moving along the edge of the top there. Somebody's got an eye on us right now, Frank. D'ye reckon it could be one of those rustlers; and would they try to hold us up so as to get our mounts?"

Bob instinctively snatched his rifle, and began to make a demonstration, as though half tempted to shoot. His action looked so decidedly hostile that it naturally created something of a panic in the breast of the unknown who was lying concealed behind the fringe of bushes.

They saw a sudden hasty movement, as though, in alarm, the hidden one had started to change his position. Then something not down on the bills occurred.

The loose earth at the edge of the top of the long slope seemed to give way in a treacherous manner. Immediately a human figure came into view, struggling, clawing desperately, and trying in every way possible to clutch at something firm in order to halt his downward progress.

But it was all of no avail. A second figure attempted to grasp the imperiled one in time, but evidently failed to secure a firm hold. And so the fellow started to roll down the slope. He came much after the manner in which a bag of corn might turn over and over. Sometimes he was head-first; and then again resuming the side motion, he whirled around in a way that was enough to make anyone dizzy.

All the while he kept letting out shrill squeals of real alarm; as though the prospect of a final plunge into that deep dark pool at the base filled him with dread.

By some rare chance the rolling man struck the twisted little cedar that tried to keep its dying hold on the scanty soil half way up the rise. Caught by the seat of his stout trousers on one of the scrubby tree's broken branches, the unfortunate one was suspended in midair, kicking, floundering and yelling at a tremendous rate.

"Say!" exclaimed Frank, when he was able to catch his breath again, "What d'ye think of that, now? Our friend Peg is so glad to see us he couldn't wait to walk down, but tried to skate. And see what's happened to him! Next thing he wants is a bath; and I sure reckon he's due for one when that cedar pulls out its last root. Wow!"



CHAPTER X

THREATS OF TROUBLE

"Splash!"

Hardly had Frank ventured upon his prediction before it came true. The stout cloth of which Peg's garments were composed might have sustained his weight indefinitely, and had it depended on his trousers giving way, his friends above must have been compelled to use their ropes in order to release him from so unfortunate a predicament.

But the roots of the little stunted cedar were soon torn from their hold. And when this came about, of course the unfortunate Peg continued his roll down the balance of that steep slope, clawing at every object which he thought might stay his progress.

He certainly did drop into the pool with a tremendous splash that sent the water flying in every direction.

At first he vanished entirely from view. Then his head emerged, and it could be seen that he was swimming furiously to keep afloat. Somehow his awkward movements made Bob Archer think of a hippopotamus he had once seen in a tank.

Peg must have had his mouth open when he struck. Perhaps he was trying to shout for somebody to stop him, and in this manner he swallowed a quantity of water. At any rate he spouted forth quite a little fluid as he floundered about, kicking and beating with feet and hands, as though he were being run by an engine that had gone wild.

Both of the saddle boys grinned. They could not help it, the thing looked so laughable. Had it been a dear friend, instead of an enemy, they must have enjoyed the sight just the same.

Twice Peg bobbed under, to come up again, paddling for all the world like a puppy that was having its first swim. His face had taken on a look of terror.

"Help! Can't keep up much longer! Something pulling me down!" he spluttered.

Frank and Bob exchanged a quick glance. Of course this put quite another face on the matter. If Peg was really in danger they had no business to stand there, laughing. It might seem funny to them, but to Peg the matter was not at all comical.

"I don't believe the critter knows how to swim, Bob!" exclaimed Frank.

"That's what," answered the other, seriously. "He's just keeping up because he's crazy with fright. We've got to get him out of there, Frank."

"We sure have; come along," echoed the western boy.

Fortunately Frank was possessed of a quick mind. He never wasted any time in wondering what methods he should use in order to accomplish things.

The pool was of considerable width, and even though he bent over its border he would not be able to come within five feet of the struggling Peg.

Without hesitation he stepped into the water, holding his gun. Two feet from the bank and it was to his knees. But he believed he had now reached a point where he could hold out his rifle and touch Peg.

"Take hold, and I'll pull you out!" he called, as he extended the gun.

It was laughable to see how eagerly the other seized upon the chance. And, when Peg had fastened himself to the other end of the rifle Frank easily drew him shoreward.

The bully came out, dripping wet, and in anything but an angelic temper. It was bad enough, in his eyes, to have fallen into the pool; but to be rescued by a fellow he hated, as he did Frank Haywood, added to the aggravation.

After spluttering for a minute or two, so that he could get rid of the balance of the water he had swallowed, Peg faced the two chums.

Strange to say he did not seem to consider that Frank had placed him under any obligations in the least when he dragged him out of the water.

"See what you did," Peg exclaimed, now spluttering with burning anger. "What d'ye mean pointing your old gun up at me, and making as if you meant to shoot?"

"Oh!" remarked Bob, elevating his eyebrows; "was that what forced you to take that header down the slope? Well, now, we had an idea you were so glad to see us that you just couldn't wait to walk down, but wanted to fly! But, if I was to blame at all for your trouble, I'm sure I'm sorry. But you see, we didn't know whether we were going to be held up by rustlers or Indians. That's what comes from hiding, Peg."

"Bah! guess I'll do just whatever I want," spluttered the other, wiping his dripping face on his sleeve without doing either much good, however. "And do you know what I think?"

"Well, no, I must say I don't happen to be a mind reader, Peg. Suppose you tell me," replied the unruffled Bob, who had taken the measure of the other, and knew he might be set down as a great boaster, but one not particularly dangerous when it came to a show-down.

"I believe you just did that on purpose, that's what," Peg went on, hotly. "You've got it in for me ever since that time we had our little affair, when I laid a hand on the Mexican girl who sassed me. You just knew I'd jump up in a hurry if you made out you was going to shoot; and I bet you even remembered this lake at the bottom of the slope. Oh! it worked all right; but don't you forget; my time will come. I'm going to pay you back in full! I've got friends who'll stick by me, all right. Bah! what're you two fellers doing here on Thunder Mountain, anyhow?"

A new suspicion had apparently seized upon Peg. He viewed their presence as a personal insult; just as though they might have plotted to forestall him in the glorious adventure he had planned to carry out.

"Well, if the old mountain belongs to you," spoke up Frank, thinking it time he took a hand in the talk, "we'll ask you to excuse us, and back out. But I don't think you have any claim on it; so we'll hang around as long as we see fit. And remember this, Peg, we're going to mind our own business; but we don't stand for any bother from you, or those with you. Understand that?"

Peg looked at him long and steadily. The eyes of Frank never wavered in the slightest degree.

"All right," said Peg, finally, as his own eyes dropped. "You wait and see; that's what! This thing's been hanging fire a long time now; and some day we're bound to have it out, Frank Haywood. My dad's after yours with a sharp stick; and perhaps the trouble is going to come down to the next generation. You'll get yours good and plenty when the right time comes!"

He turned away, and, limping to where the slope could be reached by skirting the edge of the pool, laboriously commenced to climb, following the tracks of the three horses.

"There's one of his guides up yonder, Frank," remarked Bob; "sitting on the top of the bank. Looks to me like he was grinning to beat the band."

"Yes, that's Nick Jennings," replied Frank. "Used to work on the Circle Ranch, but he got his walking papers because he was caught stealing from the other men. He's got a grudge against me because I'm a Haywood. But Nick likes a joke as well as any cowboy; and who could keep a straight face after seeing what happened here? Look a little farther on, and you'll just glimpse the colored handkerchief Spanish Joe wears on his head."

"I see him peeping at us from behind the bushes," returned Bob. "And say, he's handling that gun of his just like he'd be glad to use it if anybody gave him the dare. I reckon Spanish Joe is some ugly customer, Frank."

"That's just what he is; but let's be moving on. If Peg takes another flop and splashes in this puddle again, he'll have to swim for it, or else depend on his own guides to yank him out. No more for me. I'm wet to the knees; and did you hear him thank me for it? He's sure the limit."

So the two boys went on.

They were not interfered with, which pleased Frank not a little. Knowing the nature of Spanish Joe, and the revengeful character of Nick Jennings, he would not have been much surprised had they attacked him and Bob, and carried things with a high hand.

Presently a turn in the canyon shut out the scene of their late adventure. The last glimpse they had of Peg Grant, he had nearly arrived at the top of the slope, and it seemed possible that he would not make a slip that might cause him to repeat his recent circus act.

"Why do you think they left the trail, and made their horses climb up?" asked Bob, presently.

"Well, they might have talked it over just as we did, and chosen to leave the horses so they could look around on foot," Frank replied.

"But you suspect they might have another reason, too?" Bob insisted.

"That's a fact," replied his chum, seriously. "For all we know they may have run across some sign of the rustlers, and thought it best to get out of the beaten rut here before they got caught."

"Then you don't believe that little Lopez had anything to do with it, Frank?"

"What, that Mex boy? Oh! he's out of the business long ago," replied the other.

"In what way? Didn't he come along this trail ahead of us?" asked Bob.

"Sure thing," Frank went on. "But you see I've missed the marks of that burro's little hoofs for nearly twenty minutes. I made up my mind Lopez had some slick way of climbing out of the barranca a ways back, without leaving much of any trail. I told you he was a sly one, and I say the same now, no matter whether he's a brother to the girl you defended against Peg, or the girl herself."

"All right, Frank. Get us out of this as soon as you can," Bob remarked, looking ahead, as though he did not much fancy the appearance of things there.

Ten minutes later Frank drew rein sharply.

"What's doing?" asked Bob, nervously, as he half raised his rifle, which he had insisted on holding in his hand all the time since that meeting with Peg. "Think you see signs of trouble from Peg and his bunch; or is it something else?"

"Something else this time," remarked Frank. "Fact is, our chance has come to get up out of here with the nags!"



CHAPTER XI

THE BLACK NIGHT

"How does this suit you, Bob?"

Frank asked this question as he and his comrade sat there in their saddles, and glanced around at the peaceful scene. They had climbed the bank of the barranca, and reached a spot where the grass was growing under a cluster of mesquite trees.

"It looks good enough for me," replied the young Kentuckian.

"Plenty of forage for the horses," Frank went on, nodding his head as he looked; "and do you see that little trickling stream of water that crawls along? All we have to do is to hide the horses here. When we want 'em, the chances are we'll find 'em safe."

"I hope so," remarked Bob, as he alighted.

In a short time they had removed saddles and bridles, hiding these among the neighboring rocks, together with their supplies, and had picketed the horses by means of the lariats.

"Now what?" asked Bob.

"You sit down here, and wait till I come back," Frank remarked.

"What are you going to do?" the Kentucky lad inquired; "something that I might lend a hand at?"

"No, I reckon you're a little shy on knowing how to hide a trail, Bob. Old Hank showed me, and I've practiced it often. This promises to be a chance to see whether I learned my lesson half-way decent."

"Oh! all right, Frank. But some day I expect you to show me all about that sort of thing. You know I want to be in the swim, and learn how to do everything there is. I'll wait here by the water," and Bob dropped down to rest.

"I won't be gone long," Frank observed. "Pretty much all the slope was made up of stone; and what a great time the horses did have, trying to hang on. Once I thought your nag was going to take a nasty plunge, because he isn't as used to the work as a Western pony would be. But he recovered, thanks to the help you gave him, and made the top all right. So-long, Bob."

"I notice you're taking your gun along," remarked the one who was to stay.

"Well, when you're in the mountains it's just as well to be prepared all the time. You never can tell when you'll run slap into something. It might be a big grizzly like the one we met; then perhaps a hungry panther might take a notion to tackle you. I knew a cowman who had that happen to him. Yes, and perhaps you heard him tell the story."

"You must mean Ike Lasker," Bob replied, quickly. "Yes, I remember how he said he was lying down, waiting for some feeding deer off to windward to work closer, when, all of a sudden, something struck him on the back, and nearly knocked the wind out of him for keeps. He managed to get his knife out, and they had it there, good and hard."

"Ike said he nearly cashed in his checks that time," Frank added. "Some of his mates found him, after they discovered his horse feeding near by. The panther was dead as a stone, and Ike was clawed and bit till he looked like a map of the delta of the Mississippi—anyhow, that's the way he told it. Keep your shooter handy, too, Bob."

"I will that," returned the Kentucky boy, impressed by his chum's earnestness.

After a little while Frank came back again. His manner told that he was quite satisfied with what he had done.

"A sharp-eyed trailer might find where we left the canyon," he admitted; "but I don't believe any ordinary fellow would notice the marks. So I think our horses stand a first class chance of being here when we come back for 'em."

Bob got on his feet.

"I've fixed up some grub, just as you told me," he remarked. "It isn't much, but ought to serve in a pinch."

"And as it's nearly noon now," observed Frank. "Why not take a snack before we leave our base of supplies? Let's get the stuff out of the cache again, and have a round of bites."

"I don't see the use of hurrying away from here right now, anyhow," Bob remarked, while they were eating.

"You mean," said Frank, "that we only came here to see what we could find out about the secret of old Thunder Mountain, and why it kicks up such a rumpus every little while?"

"Yes, and seems to me that since we're right on the ground now, we might just as well start business, here," Bob asserted.

"That is, hang around until night, and wait to see if the grinding begins again, as it did when we were in camp below?"

"We'd be in a position to guess what it was, better than before," Bob went on.

"That's a fact," laughed Frank. "And if, as lots of people think, this old mountain is a played-out volcano, perhaps we might even smell the sulphur cooking, by sticking our noses down into some of these crevices in the rocks."

"Now you're joshing me, Frank!" declared the Kentucky lad, reprovingly.

"I am not," replied the other, immediately. "Suppose there was any truth in that fairy story about the fires away down in the earth here; don't you think a fellow might get a whiff of the brimstone if he was Johnny on the spot? Why, honest now, Bob, it was on my mind to find some sort of cave up here, and go in just as far as we could. Don't you see the point?"

"Oh! I reckon I do, Frank. You take little stock in that yarn; but, all the same, you think we ought to look into it, now we're on the ground?"

"That's it, Bob. Why, even my dad kind of favors that idea, and I want to either prove it a fake, or learn that there's something to it."

So they lay there, lazily enough, instead of climbing farther up the side of the mountain. It was very pleasant to keep in the cool shade of the trees, with that trickling little stream so near, for, as the afternoon advanced, it seemed as though the air became very oppressive.

Frank was looking up at the sky many times, and finally his companion asked him what was on his mind.

"I don't pretend to be a weather sharp," Frank replied; "but, all the same, there are signs up there that've got me guessing."

"Well, it is clouding up some," replied Bob, as he swept a look around at what they could see of the arch overhead. "Perhaps the long drought is going to be broken at last, Frank. Your father will be tickled, if it turns out that way. He's been complaining of late about the stock having to hunt twice as far away from the ranch for forage. A rain would make things green again."

"Sure it would," replied Frank; "but, as I said to you before, a rain storm up in the Rockies is sometimes no joke. We may have to do some tall climbing if it gets a whack at us when we're in the canyon."

The day was passing. They had seen nothing more of Peg Grant and his two guides, but could easily believe the others were not a great way off. Perhaps they, too, were only waiting for night to come in order to start their investigation.

"I don't think either Spanish Joe, or Nick, could be depended on, if the thing began to look too spooky," Frank had said more than once, showing that his thoughts must be running in the direction of the rival party.

"Oh! this is easy," chuckled Bob. "If all we've got to do is to squat here and take notes when the menagerie begins to wake up, it's going to be a snap."

Frank did not want to make his chum nervous by confessing that he had another reason for agreeing to remain there idle the balance of the day, besides the fact of there being no hurry, and that they could take notes just as easy there as farther up the mountain.

The fact was, he had concluded, it would be safer for them to remain in hiding while daylight lasted, and do what searching they expected to accomplish in the darkness of night.

It was too easy, for anyone who had no scruples, and wished to do them injury, to drop a rock down from the wall of the canyon. Against this sort of attack their rifles would be useless; and terrible damage might result.

As to who would be guilty of such an outrage, Frank only remembered that Peg was in a white heat of indignation, and fully capable of doing some madcap prank in order to frighten off the two saddle boys. He was also not a little worried about the rustlers, supposed to be lurking somewhere not far distant.

Last, but not least, there were the prospectors to whom little Lopez had admitted he was carrying the supplies that were secured on the pack burro. Frank had not heard of any treasure-hunters having invaded the slopes and valleys around Thunder Mountain; but this did not mean it could not be true.

If these men were secretly taking out possibly large quantities of precious ore, and did not wish to be discovered, or disturbed in their operations, even they might try to alarm the invaders by hostile demonstrations.

"It's as pretty a mixup as ever I heard tell of," Frank had said several times that afternoon, while they were exchanging confidences in connection with the remarkable possibilities around them. "What with the rustlers, Peg and his crowd of thunder investigators, the little Mex. boy and his unknown prospector bunch; and last but not least, Bob, ourselves, it sure has me going some."

"Yes," the other had returned, "but I hope we'll keep clear of the whole lot, and be able to find out something worth while. I wish the next night was over, and we were galloping along over the plains headed for good old Circle Ranch."

"Me too, Bob, always provided we carried with us an explanation for those deep grumblings that shake the earth, and seem to come out of the heart of Thunder Mountain. I'm a stubborn fellow, as I reckon you know; and when I throw my hat into the ring I like to stick it through till they carry me out."

"The same here," Bob had declared, after which the chums had to shake hands on it again, thus sealing the compact to stick.

And so the day went, and night came on apace.

The air did not seem to cool off to any extent as darkness approached. Frank took pains to call the attention of his comrade to this fact.

"You can guess what that means, Bob," he remarked. "It's sure going to bring on a whopper before a great while. All the signs point that way right now. So we can expect to get ready for a ducking."

"Oh! that doesn't bother me," declared Bob. "I've been through many a one. All I hope is that we don't happen to be in the old canyon when that cloudburst you mentioned comes along. I'm not hankering after a ride on a forty foot wave, and down that crooked old canyon, too. Excuse me, if you please!"

"Of course if we only stick it out here, there's going to be no danger," Frank remarked, indifferently.

"I see that you're just itching to be on the move, old fellow," ventured Bob, who knew the restless nature of his chum.

"Do you? Well, Bob, to tell the truth, if I was alone now, I suppose I'd be making for the top of the old hill, bent on finding out whether there was any sign of smoke oozing from the cracks and crevices at just the time the rumblings came on."

"Then what's to hinder both of us going at it?" demanded the proud Kentucky lad, fearful that Frank might think him timid because he had suggested their remaining out of the danger zone.

"We may, later on. Just now it's our business to get some supper; and hot or not, I'm going to make a cooking fire back of this big boulder, where nobody could ever glimpse the blaze."

"Did you say coffee?" remarked Bob. "All right, I'll go you, old fellow. I feel a little that way myself, and that's no yarn."

So Frank got things started, and it was not a great while before the coffee pot was bubbling as merrily as ever, with that appetizing odor wafting from it.

The darkness kept on increasing while they ate. An hour later it was very black all around them, and Bob viewed the possibility of their venturing into the unknown perils around them with anything but a comfortable feeling.

It was just when he was wondering whether Frank would not conclude to remain in the safe position they occupied that he heard his comrade give a sharp cry.

"What have you discovered, Frank?" asked Bob, starting to get up.

"A light up the side of the mountain yonder," replied the other, "and, Bob, perhaps if we could only manage to climb up there, we'd learn something worth while. The question is, have we the nerve to try it?"



CHAPTER XII

LOSING THEIR BEARINGS

Bob chose to consider this a direct challenge.

"I expect that it would be queer if we didn't make some sort of effort to find out what the light means. Where is it, Frank?" he remarked, with perfect coolness.

"Well, it must have gone out while you were speaking, Bob, as sure as anything," the other replied. "But I saw it, I give you my word I did. Huh! there she comes again, just like it was before. Step over here; the spur of the rock is in your way there. Now look straight up. Get it?"

"Easy, Frank. A fellow might think it was a star, if he didn't know the mountain was there. Now it's getting bigger right along."

"That's so, Bob. And yet it doesn't seem to be a fire, does it?"

"More like a lantern to me," declared the Kentucky boy. "Say, what d'ye reckon anybody could want a lantern up there for? Can you see any swinging motion to the light Frank?"

"It does seem to move, now and then, for a fact," admitted the other, after watching the gleam for a short time.

"About like a brakeman might swing his lantern if he was on a freight train in a black night, eh?" continued Bob.

"Hello! I see now what you're aiming at, Bob; you've just got a notion in your head that the lantern is being used for signalling purposes."

"Well, does that strike you as silly?" demanded Bob Archer.

"Silly? Hum! well, perhaps not, because it may be the right explanation of the thing. But whatever would anybody up there be signalling for, and who to, Bob?"

"There you've got me," laughed the other. "I'm not so far along as that yet. P'raps it might be one of the rustlers, telling something to another of the same stripe, who is located in camp out yonder on the plain. Then, again, how do we know but what it might be that Peg Grant lot? And Lopez. Don't forget little Lopez, Frank. Prospectors could have a lantern; in fact, I understand they often do carry such a thing along with 'em when they go into the mountains to pan for dust in the creek beds."

"So," said Frank, who evidently was doing considerable thinking.

They stood there for some little time, looking up at the light. Bob was merely indulging in various speculations regarding its source. On the other hand Frank busied himself in locating the strange glow, so that he might be able to know when he reached the spot, in case it was invisible at the time they arrived.

"Do we go?" asked Bob, when he, too, found his impatience getting the better of him; whereupon Frank, who had evidently been waiting for some sign, immediately took him up on it.

"If you're ready, we'll start right away," he said, quietly. "Luckily I've been studying the face of Thunder Mountain at times during the afternoon, and I reckon I can pilot the expedition all right."

But when Frank said this so confidently he failed to consider the intense darkness that might baffle all his plans of campaign. Still, Bob had the utmost confidence in his chum's ability to pull out of any ordinary difficulty. And, since his Kentucky spirit had been fully aroused, he was ready to accompany Frank anywhere, at any time.

Before they had been ten minutes on the way each of the boys sincerely wished that the idea to investigate had never appealed to them, for they began to have a rough time of it. But both were too proud to admit the fact, and so they kept crawling along over the rocks with their rifles slung on their backs, at times finding it necessary to clutch hold of bushes or saplings in order to save themselves from some tumble into holes, the actual depth of which they had no means of even guessing in the darkness.

The light was gone. Of course that might not mean it had vanished entirely; but at least it could no longer be seen by the boys who were climbing upward.

Bob was hoping his comrade would propose that they call it off, and proceed to spend the balance of the night in the first comfortable nook they ran across. But Frank himself was loath to give the first sign of a backdown. Consequently they continued the laborious task which was likely to bring no reward in its train, only the satisfaction of knowing they had accomplished the duty which they had in mind at the time of the start.

An hour must surely have gone since they first left the little green glade where the horses were staked out, and their supplies cached.

Bob found himself blown, and trembling all over with fatigue, because of the unusual exertion. The heat, too, was troublesome. But not for worlds would he be the first to complain. Frank was setting the pace, and he must be the one to call a halt.

"Phew! this is rough sledding," remarked Frank, finally, as he stopped to wipe his streaming face.

Of course Bob also came to a halt.

"Well, it is for a fact," he admitted with a little dry chuckle; for he felt really pleased to think that he had held out so long, and forced Frank to "show his hand."

"Seems to me we ought to have struck something," suggested Frank.

"Do you really mean you think we've come far enough for that?" questioned Bob.

"I reckon we have, though it's so dark I can't be dead sure. You don't happen to glimpse anything queer around here, do you, Bob?" and while speaking Frank, perhaps unconsciously, lowered his voice more or less.

"Nary a thing," replied the other, breathing fast, as if to make up for lost time.

"And I don't get any whiff of smoke, do you?" continued Frank.

"Oh! you're thinking about that volcano business again, eh?" chuckled Bob. "Nothing doing, Frank. Gee! we must be up pretty high here!"

"Feels like it," returned the prairie boy, accustomed to the heavier air of the lower levels at all times. "Makes me breathe faster, you know. But that was a hot old climb, Bob."

"All black up yonder in the sky, with never a star showing," observed the boy from Kentucky.

"Oh! we're going to get it, sooner or later," declared Frank, cheerfully. "Can't escape a ducking, I take it. But here we are, half way up old Thunder Mountain, and not a thing to show for our work. That's what I call tough!"

"Got enough?" asked his chum, invitingly.

"You mean of course for to-night only, because you'd never think of such a thing as giving up the game so early, Bob?"

"Well, I was only going to make a little suggestion," returned the other.

"Hit her up, then; though perhaps I could guess what it's like, Bob."

"All right then. You know what I mean—and that since we're away up here, we might as well make up our minds to hunt an overhanging ledge, and take a nap. But say, what're you sniffing that way for, Frank?"

"Just imagined that I got a faint whiff of smoke; but of course it was all in my eye," replied the other.

"Was it? I tell you I had a scent of it myself right then," declared the taller lad, showing signs of considerable excitement.

"Seems to come and go, then, for I don't get it any more. What was it like, Bob? Did you ever smell sulphur burning?"

"Lots of times, and helped to use it too, disinfecting," replied Bob, readily. "Spent months with my uncle, who is a doctor in Cincinnati, during an epidemic, and he often had to clean out rookeries just to stamp out the disease. But this wasn't any sulphur odor I caught, Frank."

"Then you could recognize it; eh?" asked his chum.

"It was burning wood, I give you my word for that," replied Bob, firmly.

"Hum. That sounds more like it. We'll let the volcano matter sizzle for a little while, and look around for something smaller. Burning wood must mean a fire, Bob!"

"That's what they say, always; where there's smoke there must be fire. But it seems to me we ought to see such a thing on this black night, Frank."

"Unless it's hidden, as we make our cooking fire; or else the blaze is at the last gasp. Then, after all, we may have been a little off about that light we saw," Frank continued.

"The one we said was a lantern? Then you think, now, it might have been a fire?" questioned the Kentucky lad.

"Well, I just don't know what to think. But let's look around a bit, and see if we can locate this fire," Frank suggested.

After moving around for a short time as well as the darkness allowed the two boys came together again.

"No luck, eh?" questioned Frank.

"Didn't find a thing; but I stumbled over a creek and came near taking a header down-grade that would have made that plunge of Peg's take a back seat. Just in the nick of time I managed to grab a little tree. Phew! it shook me up, though," and Bob rubbed one of his shins as though he might have "barked" it at the time of the encounter.

"Same here; only I didn't happen to fall," replied Frank.

"So it seems as if we were no better off than before," remarked Bob, dejectedly.

"We've learned where the fire isn't, if that's any satisfaction to us," chuckled his chum, trying to make the best of a bad bargain.

"And that smoke smells so meaning-like, it's sure a shame we can't just get a line on where it comes from," Bob went on to say.

Frank seemed to catch a significance in his words, for he turned sharply on his companion, saying:

"Look here, have you been getting a whiff of it again, Bob?"

"Why, yes, several of 'em in fact, Frank," replied the other, in what seemed to be a surprised tone. "But what does that matter, when neither of us can find any fire around? I sniffed and sniffed, but although I just turned my eyes in every direction not even a tiny spark could I see. And that happened just three times, Frank."

"What! do you mean you smelled smoke three separate times since you left me?" demanded the saddle boy.

"I'm sure it must have been three, because it was between the first and second times that I tripped. Yes, and always in just the same place too, which was queer enough."

"That sounds kind of encouraging, Bob," declared Frank.

"Do you think so?" asked the other, puzzled to account for Frank's newly awakened interest. "Tell me why, won't you, please, Frank?"

"Sure, after you have answered me a question," Frank promptly remarked.

"All right, let's have it, then," his chum returned.

"Do you think you could find that exact spot again?" asked Frank.

"Meaning where I sniffed that smoke each time? Why, I guess I can, because I went back there twice, all right. Couldn't be quite satisfied that there wasn't something around there I ought to discover. But it turned out a fizzle, Frank."

"Perhaps it wouldn't be so unkind to me, though," the Western boy declared. "Take me to that place, Bob, and right away. It strikes me I'd just like to get another little whiff of that same wood smell, myself. It wouldn't be the first time I'd followed up a smoke trail."

"Gracious! that sounds interesting, and I hope you can do it, Frank!" breathed Bob, his admiration for his chum awakening once more.

"First of all, get me to that place. Lead off, and I'll be close at your heels. And, Bob, don't forget that spot where you came near having your tumble. Keep your level head about you."

"I'll sure try to, Frank. Come on then."

Bob led the way through the darkness. Although he had been out West for so short a time Bob Archer was rapidly learning the ways practiced by those who live close to Nature. He began to observe always all that he saw, and in such a way that he could describe it again, in every detail.

And so it chanced that, having marked his course when coming back after his unsuccessful search for the fire, he was able, not only to lead his comrade thither, but to warn him every time they approached a dangerous slide, where a trip might hurl one some hundreds of feet down the face of Thunder Mountain.

"Here is the place, Frank," Bob suddenly said, in a cautious whisper.



CHAPTER XIII

THE SMOKE TRAIL

"Are you sure of it?" asked Frank, in the same low voice.

"Why, try for yourself, and see if you can't get a whiff of smoke right now," Bob replied.

"You're right, because I caught it just then; but I reckon the wind must be changing some, for it's gone again," Frank remarked.

"You never spoke truer words, Frank, because I can hear the breeze beginning to shake the leaves in the trees up yonder, and it wasn't doing that before."

Bob pointed upwards as he said this cautiously. And Frank, always watchful, noticed a certain fact. The trees were so situated that they could be said to lie almost in a direct Southeast line from where he and Bob stood! This might appear to be a very small matter, and hardly worthy of notice; but according to Frank's view it was apt to prove of considerable moment, in view of what was likely to follow.

"Well, as the smoke's gone again, let's see if we can locate it by moving a little this way," and Frank led off as he spoke, with Bob following.

Both lads were very cautious now. Even Bob, greenhorn as he was, so far as Western ways were concerned, understood the need of care when approaching a camp that might be occupied by enemies. And as for Frank, he had not been in the company of an old ranger like Hank Coombs many times without learning considerable.

They had not been moving in the new direction more than five minutes when Bob reached out his hand and clutched the sleeve of his chum's jacket.

"What is it?" asked the leader, stopping short, and crouching there.

"I got it again, Frank," whispered the Kentucky boy, eagerly.

"Sure," replied his comrade, immediately. "Why, I've been smelling smoke for more'n a whole minute now. And I'm following it up, foot by foot."

"Oh!" murmured Bob, taken aback by this intelligence.

"Don't say a word above your breath, Bob. Whoever it is can't be far away now. We may run in on 'em any minute, you know," and as if to emphasize the need of caution Frank drew his chum close while he whispered these words directly in his ear.

Bob did not make any verbal reply; but he gave the other's sleeve a jerk that was intented [Transcriber's note: intended?] to tell Frank he understood, and would be careful. Then they moved along again.

It was no easy task making progress through the darkness, and over such rough grounds, without causing any sound. Bob found that he had almost to get down on his hands and knees and creep, in order to accomplish it. But his chum had not forgotten that he was new to this sort of business, and hence he gave Bob plenty of time.

Then Bob in turn began sniffing, and Frank knew that now he, too, had caught the trail-odor, which was constantly becoming stronger. Thus they were positive that while they moved forward they must be gradually drawing nearer the source of the smoke.

Another tug came at Frank's sleeve, at which signal he bent his head low so that his chum might say what he wanted in his ear.

"Sounds like voices!" whispered the excited Kentucky lad.

Frank gave a little affirmative grunt.

"Rustlers, maybe?" Bob went on.

The other made a low sound that somehow Bob seemed to interpret as meaning a negative to his question.

"Then prospectors—Lopez and his bunch?"

"Uh!" Frank replied; and then himself lowering his lips to the ear of Bob he went on: "What's the matter with Peg and his crowd? They might have got up here ahead of us. Quiet now!"

Bob did not attempt to say another word. He had new food for thought. Yes, to be sure, Peg and his two cowboy guides had had plenty of time to climb that far up the side of Thunder Mountain. If they had taken daylight for the task of course they avoided the danger of getting lost, such as had overtaken the saddle boys. And if the nerve of Spanish Joe and Nick Jennings continued to hold out, when strange things began to happen, the boastful tenderfoot from the East stood a chance of making a discovery.

As the two crept closer, on hands and knees, they could hear the murmur of voices grow louder, even though the speakers were evidently talking in low tones. While the experience was altogether new to Bob, he enjoyed it immensely. Why, after all, it was not so very hard to place his hands and knees in such fashion that he felt able to move along almost as silently as a snake might have done.

Now he was even able to locate the spot from which the murmur of voices came. Yes, and when he looked closer he saw a tiny spark that glowed regularly, just as a firefly might sparkle every ten seconds or so.

Bob solved that little mystery easily. Of course it was Spanish Joe, smoking one of the little cigarettes which he was so frequently rolling between his fingers.

To be sure, the odor of tobacco smoke mingled with that of burning wood. And if Spanish Joe, why not the other cowboy who was in bad repute among the ranches; yes, and Peg himself?

Bob began to wonder what the programme of his chum might be. Surely they would not take the chances of crawling up much closer now. If discovered they would run the risk of being fired upon; and besides, there was no necessity for such rashness.

Then Bob discovered that when the wind veered a little, as it seemed to be doing right along, he could actually catch what was being said.

Peg was talking at the time, and grumbling after his usual manner about something or other.

"Ten to one the fellow's gone and deserted us, Nick!" he remarked, suspicion in every word.

Apparently the lounging cowboy did not share in his opinion, for he laughed in a careless way as he drawled out:

"Oh! I reckon not, Peg. Me and Joe has hit up the pace fur some years in company, and I knows him too well to b'lieve he'd break loose from a soft snap like this here one. Jest lie low, an' he'll be back. Let's hope Joe's found out somethin' wuth knowin'."

"But he's been gone nearly an hour now," complained Peg.

"What of that? It ain't the easiest thing gettin' around on this rocky ole mounting in the pitch dark, let me tell ye, Peg," Nick remarked; and by the way he seemed to puff between each few words, Bob understood that it must be Nick who was using the cigarette, and not Spanish Joe.

"Say, that's so," admitted Peg, as if a new idea had come to him. "Perhaps he's slipped, and fallen down into one of those holes you showed me when we were coming up!"

This also amused the cowboy, for he chuckled again.

"Too easy an end for Spanish Joe," he said, carelessly. "Born fur the rope, and he can't cheat his fate. Same thing's been said 'bout me. Don't bother me none, though, and sometimes it's a real comfort; 'specially when a landslide carries ye down the side of a mounting like a railroad train, like I had happen to me. Nawthin' ain't agoin' to hurt ye if so be yer end's got to come by the rope."

"A landslide! Do they often have that sort of thing out here?" asked Peg, showing some anxiety, as though he had read about such terrible happenings, and did not care to make a close acquaintance with one.

"Sure we does, every little while," remarked Nick, cheerfully. "Why, jest last year the hull side of a peak 'bout forty mile north of here broke away, and a Injun village was wiped out. Never did hear anything from a single critter after that slip bore down on 'em."

"It might happen here on Thunder Mountain, too, couldn't it, Nick?" pursued Peg, as if the subject, with all it pictured to his active mind, held his interest gripped in such a fashion that he could not shake himself free.

"Easiest thing goin', Peg. And let me tell ye, if it ever do happen here, thar's agoin' to be a slide to beat the band!" Nick asserted, positively.

"But what makes you say that, Nick?" demanded the boy.

"Oh! lots of people says the same thing," replied the other, as if carelessly.

"That a landslide is going to start things going on Thunder Mountain any time—is that what you mean?" Peg insisted on repeating.

"Any day, er night. Things have been lookin' that way for some time now. I reckon she's due with the next big cloud-burst that sails this way."

It was evident that, for some reason, Nick was trying to frighten his young employer. Perhaps he himself really wished to get away from the mountain with the bad name; and took this means of accomplishing his end without showing his hand. If that were true, then he was gaining his end, for Peg certainly gave evidence of increasing uneasiness.

"But why didn't you tell me all this before?" he demanded, indignantly.

"What was the use, boss? Ye was sot on comin' here, and ye made Joe and me a rattlin' good offer. 'Sides, it didn't matter much to me. I had my life insured. A rope might have skeered me; but say, I don't keer that for landslips," and Nick snapped his fingers contemptuously.

But Frank, who knew the sly cow puncher so well, believed that more or less of his indifference was assumed.

"Well, I do!" declared Peg, with emphasis; "and if I'd only known about that sort of thing before, blessed if I'd a come. I've heard what happens when the side of a mountain tears away, and how everything in the path goes along. They showed me the bare wall where one broke loose up in Colorado. Say, it was the worst sight ever. You'll have to excuse me from nosing around here another day, if that sort of thing is hanging over this place. Me for the ranch on the jump. Get that, Nick?"

"Oh! now, what's the use botherin'? Chances are three to one they ain't agoin' to be any sech upsets as that yet awhile," the cowboy said.

"Only three to one!" burst out Peg. "All right, you can stick it out if you want, and I'll pay you all I agreed; but just you understand, Nick Jennings, when to-morrow comes, I want you to get me down on the prairie, where I can make a blue streak for the X-bar-X ranch house."

"But ye sed as how ye was detarmined to find out what made them roarin' n'ises, up here on old Thunder Mountain!" protested the guide, although he evidently expressed himself in this way only to further arouse the obstinate boy.

"I've changed my plans, that's all," Peg announced. "Any fellow can do that. It's always the privilege of a gentleman to alter his mind. I'd like to crow over Frank Haywood and that greenhorn chum of his mighty well; but I ain't going to run the chance of being carried down in a landslip just for that. Huh! I guess not! What I said, stands, Nick. And I hope the old slide comes while those two chaps are on the mountain; yes, and gives them a dandy free ride, to boot!"

"Oh! jest as ye say, Peg! I'm willin' to do anythin' to please ye. But p'raps we ain't goin' to git off so easy arter all," remarked Nick, suggestively.

"Now, what do you mean by hinting in that way? And I've noticed you twisting your neck to look up at the sky more'n a few times. Think it's going to rain, do you?" demanded Peg.

"Don't think nawthin' 'bout it; I know it be." And, Nick added, with emphasis, "I reckons as how it'll be jest a screamer when she comes."

"A storm, you mean?"

"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.

"Nawthin' 'cept stick it out, I reckons," replied Nick Jennings.

The superstitious cowboy was more or less anxious, himself. Frank, eagerly listening, could tell this from the way in which the fellow spoke. But Nick did not mean to fall into a panic. To try and rush down the precipitous side of that mountain in the dark would be madness. And with all his faults Nick was at least smart enough to understand what it meant by "jumping from the frying pan into the fire."

Another roar, louder than any that had yet broken forth, interrupted the excited conversation between the son of the mining millionaire and his guide. The whole mountain quivered. Bob himself was much impressed, and began to wonder more than ever what it could mean.

The noise died away, just as thunder generally does, growing fainter, until silence once more brooded over that wonderful mountain. Then again the two crouching lads caught the complaining voice of Peg. Bully that he was under ordinary conditions, he now showed his true colors. That awful sound, coming from the heart of the rocky mountain, as it seemed, had terrified Peg.

But Frank was not surprised, for he had all along believed that a fellow who could lift his hand to strike a small girl must be a coward at heart, no matter how much he might bluster and brag.

"This is terrible, Nick!" exclaimed Peg. "Can't you think of some way we might get out of this? Oh! I'd give a thousand dollars right now if only I was safe down on the plains again! What a fool I was to come here!"

"Well," drawled Nick, possibly with a touch of real envy in his voice, "I'd like right smart to 'arn that thousand, sure I would, Peg. But hang me if I kin see how it's agoin' to be done. We can't slide down; walkin's a risky business, and likely to take hours; an' right now I don't feel any wings asproutin' out of my shoulders, even if you do."

"Oh stop joking, Nick, and talk sense," complained Peg. "We've just got to do something. Why, the old mountain might take a notion to slide, and carry us along with it."

"I sure hopes not, at least right now," replied Nick, uneasily. "But I do reckons as how we're agoin' to git that storm afore mornin'."

"But see here, Nick," Peg went on, anxiously; "didn't you notice anything when you were leading me up here like a lamb to the slaughter? I mean, you ought to have seen whether this side of the old mountain was more likely to drop off than any other."

"Ye never kin tell nawthin' about such things," returned the cowboy. "Reckons all we kin do is to root around, an' see if we might find some sorter cave, where we'd be safe from the rain, if so be she comes arter a while."

"A cave!" echoed the other, as though startled. "What under the sun do we want to get inside the mountain for? Don't you understand that all that noise is coming out of this old thing? I tell you, I believe it is a volcano, just as they told me, and perhaps she's going to break loose this very night!"

"Hey! what ye a sayin' that for?" demanded Nick. "Supposin' she is what ye tell, that ain't any reason the explosion's got to come this particular night, is it? She's kept on a growling for a hundred year now, an' nawthin's happened. Reckons it ain't agoin' to come off jest acause we pilgrims happens to be up here."

"But you said we ought to find a cave, and go in, Nick," continued the youth. "Suppose we do, and the sulphur fumes suffocate us? They must be just awful inside the mountain. This is a nice pickle for me to get into! If I stay out here I'm in danger of being drowned, or swept away by a landslide; if I go inside there's all the chance in the world that I'll be soaking in poisonous sulphur gas till I keel over. I'm up against it good and hard."

"We're all in the same boat, remember, Peg," declared the cowboy.

"But you knew more about this thing than I did, Nick. Why'd you let me come? It was all a fool business, and you're most to blame," protested Peg.

"Aw! let up on that kind of talk, will ye?" growled the cowboy, who was himself losing his respect for his employer, owing to the presence of those things which he did not understand, and the nearness of which aroused his own fears.

"I will, Nick; only get me out of this hole safe and sound, and I give you my word I'll pay you that thousand dollars. But where do you suppose Joe can be all this time? Has he run away, or dropped over into one of those pits we saw on the way up here? I wish he'd show up. Three would be better than two; and perhaps Joe might have a plan for us to get out of this."

Again did the low grumbling sound begin again, and silenced the conversation between Peg Grant and his cowboy guide, every word of which had come distinctly to the ears of the crouching saddle boys near by.

The rumble grew rapidly in volume, until once more the whole great mountain seemed to tremble. Bob was shivering partly from the excitement, and because he felt a touch of alarm.

But he could not help noticing the actions of his chum. When the thunderous roar was about at its height Frank had thrown himself flat on the ground. Bob could not see what he was doing, but his groping hand came in contact with the head of his comrade; and he discovered that it rested on the ground, with one ear pressed to the rock.

Frank was listening!

He knew how the ground carried sounds more distinctly than the air, and evidently he hoped to discover something concerning the thunder by this method of wireless telegraphy.

Then, as the volume of sound gradually decreased, just as a lion's roar dies away, Bob discovered that Peg and Nick were undoubtedly moving off. He supposed that Nick had made up his mind to hunt for an outcropping ledge, or some friendly opening, where he could be sheltered from the storm; and as Peg dared not stay alone, he was compelled to accompany his guide. The complaining voice of the rich man's son could be heard for a minute or so. Then even that ceased.

"They're gone, Frank!" exclaimed Bob.

"Yes, I know it," replied the other, as he arose from his position flat on the rocks. "And Peg is badly rattled, too. Say, I always told you he lacked real grit, and this proves it. He's scared at that noise. Think of him wanting to fly down to the plain! I reckon he's had about all of the exploring he wants. It's 'take me back to my daddy!' now with Peg."

"Well," remarked Bob, with a sigh, "I don't blame him so very much, Frank. I tell you what, that noise is enough to give anybody fits. I'm all of a tremble myself, and I'm honest enough to admit it."

"That's all right, Bob," replied his chum, quickly; "but are you ready to give the game up here and now?"

"Who, me?" answered the Kentucky boy, instantly; "well, I should say not—not by a long sight! No matter what comes, I'm ready to stick it out on this line if it takes all summer!"

"Just what I thought," chuckled Frank. "That's what makes all the difference between a brave fellow and a coward. Why, to tell you the truth, Bob, I'm shaking all over right now myself; but it isn't with fear. I'm excited, curious, and worked up; so are you. When you say you don't want to back out it tells the story that you're not afraid."

"But it wouldn't make any difference, Frank, seeing that we couldn't get away from here, even if we wanted to just now," remarked Bob.

"That's so," returned his chum; "just as Nick said; we're here, and we've just got to stick it out, no matter what comes."

"But do you take any stock in what Peg said about an avalanche?" asked Bob.

"Mighty little," Frank replied. "This mountain is made up mostly of solid rock. That's what makes lots of people believe in the volcano idea. A slide would be hard to start here, and it just couldn't carry much along with It. Where mountains have sides made up of earth and loose rocks, that happens sometimes."

"I'm glad to hear that," remarked the other. "But there comes another shake. Whew! feel how she trembles, Frank! Whatever sort of power can it be that makes this noise and shivering sensation?"

Frank waited until the convulsion had passed before replying.

"I've got a strong suspicion, Bob," He said, finally; "and it's something that came into my mind since feeling the sound, for that's the only way I can express it. Now, what does it make you think of, most of all?"

"I did think it was thunder," declared Bob; "but now it seems to me the only thing I can compare it to is the beating of the terrible billows against the coast away up in Maine, when a fierce northeast storm is blowing. They seemed to make the rocks quiver just as this does now."

If Frank had intended to reply to this remark he was prevented by something unexpected that happened just then. This time it was not the furious roar of the unknown force within the mountain that disturbed him; but a cry that rang out shrilly.

"Help! Help!"

Bob clutched his companion's arm.

"Something has happened to Peg!" he exclaimed. "Perhaps the guide has thrown him over, and he's lost, and scared nearly to death!"

But Frank was more accustomed to reading voices in the open than was his chum.

"No, you're wrong there!" he cried, "that's Spanish Joe yelping; and he must be in a bad hole to call for his companions. Come on, Bob, we've just got to see what we can do to help him. Rascal that he is, he's human. Follow me!"