Preparations for exploring the mysterious tunnel on this occasion were much more complete and elaborate than when Bud, Dick and Nort walked through it before. And they did not rush off in haste, the moment it was discovered that the water no longer came through the reservoir end of the pipe line that formed the beginning and end of the old underground stream course.
"There's water enough for nearly a week, anyhow," said Bud, in discussing their plans. "And if we can't discover the cause of the stoppage inside of that time, and get it turned on again, we may as well know that and give up Flume Valley as a bad job."
"That's right," chimed in Nort.
"The stoppage is inside the tunnel, that's sure," voiced Dick.
"Yes," answered his cousin. "The water is running in all right from the river."
This fact had been ascertained by telephone. The water was running freely from Pocut River above the dam, and into the pipe that entered the side of the mountain.
Bud's father had been told of the situation, which followed so closely on the heels of the discovery of the evil acts of Pocut Pete.
"Doesn't this sort of set you fellows back so you want to give up ranching?" Mr. Merkel asked his son and nephews.
"Not a bit!" promptly answered Bud.
"We're going to stick!" added Nort.
"And find out what makes this water stop," contributed Dick. "We'll show up Hank Fisher, Del Pinzo and that other bunch of crooks, too!"
"I don't see how Hank could have had anything to do with this water stoppage," said Mr. Merkel. "Of course it may develop that he hired Pocut Pete to infect our cattle, but even that is doubtful. Those fellows are pretty cute. Anyhow, Pocut Pete is where he can't do any harm for some time. He won't be tried until fall.
"But it's my idea, boys, that this water stoppage is caused by some natural means. We are using an old underground river bed, you realize, and there may be what I'd call a 'hole' in it somewhere. The water that ought to come to you may drop down that hole."
"But why doesn't it do it all the while?" asked Dick.
"That's one of the mysteries," said his uncle, "one that you'll have to solve."
"We went over it all before," spoke Bud, "and we couldn't see even a branch passage."
"Well, some of the men are going with you this time," his father said. "They're more used to looking for signs than you fellows are, though I must say you've done fine, so far!"
As Mr. Merkel had stated, it was decided to send several of the cowboys with Bud and his cousins on this expedition into the dark tunnel. Old Billee, Yellin' Kid and Snake Purdee would be of the party, which would thus consist of six.
In this way, there being safety in numbers, it was hoped that accidents might be avoided, or, if they happened, there would be at hand help for the unfortunates.
"If we could only take a boat," said Dick, when the preparations were almost completed, "it would be great!"
"What could we do with a boat in that stream, which is hardly three feet wide in places?" asked his brother. A boat had been mentioned in the first excitement, however, but the idea was abandoned as impracticable.
"Well, if the flood came, as suddenly as it did when we had to take refuge on the ledge, we could float out," answered Dick.
"A boat to hold six men would be too big to carry," spoke Bud. "Even a folding canvas one wouldn't answer. But I know what we can do."
"What?" asked Nort.
"We can each take an inner automobile tire. Blown up, they are as good as life preservers, and with them fastened to us we can float and be carried along by the current, if a flood happens again."
It was decided that this was a wise precaution to take, and from Diamond X some inner tubes were sent over—old ones that had outlived their usefulness on the car, but which still held air, and would, as Bud said, make excellent life preservers.
In order to make a thorough examination it was decided to take food and water enough to last the expedition at least two days. It was easy to traverse the tunnel in one day, as the boys had proved. But Old Billee counseled a slower trip.
"I wish I could go with you," said Mr. Merkel to the boys, when the time came for the start, "but I have a shipment of steers to get off, and I want to keep watch of this epidemic. It begins to look as if we had gotten the best of it, but I'm taking no chances."
"Oh, we'll make out all right, Dad," spoke Bud. "Though we would like to have you with us. And when we come back we'll either settle, for good and all, this fight for water, or we'll abandon Flume Valley!"
"I'd hate to see you give it up," said the ranchman. "It is an ideal place to raise cattle, with the water here. But without it, of course, there's no use thinking of it. Well, good luck to you," he called, as he turned to go back to Diamond X proper.
As he had said, there had been no further outbreak of the epidemic among the cattle of the boy ranchers. The steers which Pocut Pete had cut, injecting into them the pus and germs, died, however. And there were more of these than Bud and his cousins had counted on.
But if they lost no more than this half-score, and could get the water back, all might yet be well.
The water in the reservoir had gone down several feet when the expedition started into the tunnel. Much of the fluid had to be drawn off to water the thirsty cattle, for it was the height of summer now, and the heat, in the middle of the day, was terrific.
But there was still enough of the supply to last for several days. Then, if Bud and his companions could not discover the secret of the stoppage, and get the water to running again. Flume Valley would have to be abandoned.
"Well, I can't see that we can do any more," spoke Bud.
"No; you've got things as well fixed as possible," agreed Old Billee.
"Can't tell when you'll see us again," said Dick to the remaining cowboys gathered about the reservoir end of the tunnel to see the expedition start in.
"Well, good luck, anyhow!" came the answer.
A number of punchers had been sent over to Flume Valley from Diamond X and Triangle B to replace Yellin' Kid, Billee and Snake Purdee who were to accompany the boy ranchers.
Suddenly Yellin' Kid broke into song:
"Leave me alone with a rope an' a saddle,Fold my spurs under my haid!Give me a can of them sweet, yaller peaches,'Cause why? My true-love is daid!"
"Oh, give us something cheerful!" laughed Bud, as the cowboy seemed about to start on another verse.
"That's cheerful enough for this occasion," retorted Yellin' Kid. "Wait 'till you hear me howl in that tunnel."
"Don't!" begged Dick with a laugh. "It echoes so you'll bring the roof down!"
There was a hurried inspection of their weapons and supplies, for each was equally needed. The inner tubes of several auto tires had been provided and tested, and there was a small air pump with which to inflate them.
"All ready?" asked Bud, at length.
"All ready," answered Old Billee. "But I wish I had a hoss!"
"Couldn't use one," retorted Snake Purdee. "It'll work off some of the fat, if you walk."
"Hu! Fat!" snorted Old Billee. "I ain't fat!"
"Forward!" suddenly called Bud.
Then with waves of their hands, and with the calling of many "good-bye" farewells, the expedition disappeared into the black depths of the tunnel.
What would they find? What would be the outcome? Would they ever reappear again?
These were questions which more than one asked himself, but no one spoke them aloud.
"Now," remarked Bud, when they were well within the long stretch of blackness, and lanterns had been lighted, "we walked, the other time, on the left-hand side of the water course. What say we try the right one this time?"
"Good enough!" decided Old Billee. "We'll be right for once!" he joked.
"But it really is a good idea," declared Snake Purdee. "There might have been something—some hidden passage on the side you didn't travel, boys. You could easily have missed it in the darkness."
So this was decided on. As a matter of fact in many places it was possible for the party to divide and some walk along either side of the old stream bed. But this would not be feasible should the water suddenly appear again.
And so the expedition moved slowly along. I say slowly, for that speed marked their course. They carried a number of lanterns and these were flashed over walls and roof as well as on the bottom, to discover, if possible, a branch tunnel, or hole, where the water might travel to, and thus be shunted off from the reservoir end. But, for several hours nothing occurred, and nothing was discovered. Lunch was eaten in the blackness, relieved as it was only by the lanterns, and then the expedition started off again.
"Here's the place where we were when the water came spouting before," said Bud, as they came opposite the ledge on which he and his cousins had taken refuge. "I think we ought to spend some time here and——"
"Hark," suddenly interrupted Nort. "Hear that noise!"
They all heard it—a rushing, roaring sound, like the blowing of a mighty wind.
"The water—the water!" cried Bud. "Look out!"
They could hear the noise more plainly, now, and as Snake and Billee raised their lanterns, the glows flashed on a white, frothy mass approaching through the blackness of the tunnel.
"It's the same as before!" cried Nort. "Get to the ledge! The ledge!"
He made a leap, running ahead to where he saw a more narrow place that would enable him to leap across from the right to the left side of the channel.
And then, while the others hung back for a moment, and Nort thus dashed ahead alone, his companions saw him quickly disappear. The wall of water suddenly rushed forward, but it never came quite to the place where the party of five now stood in nameless terror—five, for Nort had disappeared into the depths of the stream that had so mysteriously appeared again out of the blackness.
From whence it came, and whither it was rushing, not to foam entirely over that startled group, none in it could say. But it had engulfed Nort—that they had seen.
Horror and surprise held the five speechless for a moment. Then, as they heard the noise of the rushing water, and saw, by the light of their lanterns, that it came almost to them, but suddenly turned to the right, they came to their senses.
"Nort! Nort!" yelled Dick, his voice being flung back at him in echoes from the rocky, vaulted roof of the tunnel.
"What in th' world happened?" asked Old Billee in trembling accents.
"Nort fell into the stream, and was carried away," answered Bud, his voice choking.
"But why doesn't the water reach us?" asked Snake.
"That's what we'll have to find out," asserted Bud, bravely. "Come on!"
"But be careful," cautioned Billee. "Something may happen t' us, an' then we can't help Nort! Go easy!"
He spoke only in time, for the next moment, with an exclamation of horror, Bud and Dick, who had forged ahead, recoiled back.
"Look out!" shouted Bud, and he made such a lurch backward to recover his balance that the lantern was flung from his hand. It dropped, as they all could see, into the midst of black, swirling waters, white foam-capped on top.
And it was into this stream that Nort had fallen and been carried away, and into this stream that Bud and Dick had been nearly precipitated as they dashed forward.
Bud's lantern was extinguished with a hiss as the waters penetrated it and covered the wick. It sank from sight, but not before it had, in a flash, illuminated the surface of the water.
"It's a good thing we took the right-hand side," said Billee, as he and the others saw what it was that had caused the water to rush almost to their feet and then branch off. "I mean it's a good thing, for it may help us to solve the mystery. But as for poor Nort——"
He did not finish, but Dick sent up a despairing cry:
"Nort! Oh, Nort! Where are you?"
And only the vaulty echoes answered.
"What are we going to do?" asked Snake, who seemed unable to suggest anything.
"Everybody come here with their lanterns," directed Bud. "And light that spare one, Billee."
Thus was replaced the one he had dropped in the effort to save himself from falling into the same torrent that had engulfed his cousin.
And in the light of the lanterns, the one Nort had carried being forever lost, it seemed they all could see the explanation for the apparently mysterious action of the underground stream; or, rather, it was an explanation of part of the mystery; for this was only the beginning.
Beyond where they stood, in the direction of Pocut River, there flowed through the ancient channel a body of water larger than that which usually filled the underground course. This was accounted for, likely, by the fact that it had been stopped, or dammed, by some natural or artificial means, and had suddenly been released. Thus the channel was more fully filled than usual.
But, as I have said, the water came up to the point where the members of the expedition then stood. From there it made a sudden turn to their right, as they stood facing the river end of the tunnel. And it was this sudden turn—this shift in the course of the underground stream—which prevented it from engulfing our friends.
But it had engulfed Nort.
"I see what happened—or, at least, part of it," spoke Bud while the others listened. "The waters were suddenly turned on again, or turned themselves on, and shot this way. Nort heard them and ran down here to jump across the stream-bed, which was then dry. But he must have fallen over the edge of this traverse ledge, or channel, as I nearly did, and down he went!"
They looked, and agreed that this was very likely how it had taken place.
"But can't we save him?" pleaded Dick. "I'm a good swimmer. Let me try to get him! Maybe he's lying down there—on the bottom!"
He made as if to take off his coat, but Old Billee grabbed him by the arm.
"You'd only go t' your death, boy!" said the old ranchman hoarsely. "It's bad enough—as it is!"
"But what happened to Nort?" asked Dick, and there was a sob in his voice.
"He must have been carried away—down that stream—wherever it goes," asserted Snake Purdee.
"That's just the point, where does it go?" Dick asked.
"Wait a minute," counseled Bud. "Let's see if we can reason this out." He paused to give it thought. "The way this stream is running now," he resumed, "wouldn't put any water into our reservoir, would it?"
"No," answered Yellin' Kid, and for once his voice was softened. "Th' water is all being shunted down this passage—where Nort fell."
"But," resumed Bud, "this passage has always been here. We didn't see it before, as we walked on the other side of the main channel. Then if this side channel has always been here, and we managed to get water through our pipe when it was here, it stands to reason that it must fill in time, enabling the water to run along here," and he indicated the regular channel that extended back of them out toward Flume Valley.
"That's so!" cried Old Billee. "There's an end, or a bottom, t' this channel somewhere, and poor Nort can't be carried all the way through th' earth."
"But—but," faltered Dick. "It may be too late to save him when this side passage fills up."
"What I was going to propose," went on Bud, "is that we see if we can't follow along this newly-discovered side passage, as we have been following the main bed of the underground river."
He paused to let his companions visualize this suggestion.
"Do you think that would be safe?" asked Old Billee. "I mean," he added quickly, "will that be th' safest way t' try an' save Nort? I won't back down on anything—I guess you know that—but I was just wondering if there was some other way."
"There might be," said Bud. "We could go along on the left side of the stream, and see if there is a crossing place farther on. We saw some narrow places when we were here before, but it's a question how much water they'd have in them now."
"Oh, but can't we do something?" cried Dick, now almost sobbing, though he was making a brave effort to conquer himself. "Oh, Nort! Nort! Where are you?" he cried frenziedly.
But again only the echoes answered.
"Come on!" cried Old Billee suddenly. "We'll try this way. We've got t' do something!"
"Leave our packs here," suggested Yellin' Kid, and again his voice was low, as if in deference to Dick's feelings. "We can put 'em up on that ledge," he added, indicating a small one on their side of the underground stream. "The water doesn't appear to have been up there in years. If we leave our things here we'll be better able to help Nort—if we find him," he added in a voice so low that only Old Billee heard.
"Take our lanterns," suggested Snake Purdee.
"And ropes," went on Bud. "We may need 'em!"
Accordingly the food and other supplies, which the searchers after the secret of the underground water course had brought with them, were put up on the ledge, and then they started down the black passage through which the stream appeared to have branched, carrying Nort with it. There was room but for one to walk at a time on this "bank," as it might be called, of the hidden stream, and they had to proceed in single file.
"I'd like to see a map of this place, so we'd know where we were going," spoke Old Billee, as he swung his lantern from side to side in an endeavor to disclose the hidden secrets of the place.
"I have an idea that the underground stream is shaped like the letter T," spoke Bud. "The top, or cross stem, is the part that extends from the river to our reservoir. We are now walking along the upright piece."
"But if the main part of the T is also a stream, and the water is running down that, as it is, instead of along the main stem, it becomes for the time being a letter L, doesn't it?" asked Snake.
"Yes," assented Bud. "And as long as the water turns at right angles, as it does at the place where Nort fell in, and as long as the water runs along this same side passage, we don't get any at Flume Valley. The letter T is in our favor, and L is against us."
"But we didn't see anything like this when we were here before," remarked Dick.
"Because we weren't on this side," Bud answered. "And I have an idea that, in time, this second passage finally fills with water completely, and when it does the stream again flows along the cross stem of the T and we get it."
"Mebby you're right," Old Billee agreed. "But this isn't finding Nort."
"Will we—will we ever find him?" faltered Dick.
"Sure!" declared Bud, as heartily as he could.
But as they progressed in the darkness, stopping now and then to look about by means of the light, calling again and again, and as no reply came, even the heart of the stoutest of them sank in despair.
All they could see was black, rushing water, flowing in a channel it appeared to have cut, after countless years, in the solid rock. There was a narrow footpath, so to speak, on either side of this stream, and it was along this the searchers were walking.
Suddenly Bud, who was in the lead, uttered a strange cry.
"What's the matter?" exclaimed Dick. "Do you see him?"
"No! But look!" went on Bud. "We have come out into a regular underground cave! It's as big as a house!"
He flashed his lantern around in a circle, and as the others came up and stood beside him, at a spot where the passageway beside the stream widened, they saw that they had emerged into a great vault.
And as they stood there, awed and marveling, there came to them, above the rustle and whispering of the rushing waters, the sound of a human voice—it was as though someone, sorely hurt, had moaned.
"Listen!" cried Dick.
"Hold up your lanterns!" commanded Bud sharply.
As they raised them, throwing the combined light farther out across the stream that had widened into a pool in the vault, Dick uttered a cry.
"I see him! I see Nort!" yelled Dick. "There, on the rock!"
And he pointed to the huddled figure of some one on a great rock in the middle of the pool of black water, which seemed, a short distance from the inflowing stream, to be as quiet as a lake. And, as they watched in the gleam of the lights, the figure on the rock moved slightly.
"Nort! Nort!" cried Dick, and his voice was flung back in deafening echoes from the vaulted roof.
While they eagerly watched, the solitary figure on the big rock in the midst of that sinister pool again moved slightly, and as it became partly erect it was seen to be Nort Shannon.
"We've found him! We've found him!" joyfully cried Dick.
"An' alive, too, if I'm any judge," added Billee.
Dick was stripping off his coat, when Bud placed a hand on his shoulder.
"Wait a minute," advised the western lad.
"But I'm going to get him!" objected the brother. "I'm going to save Nort!"
"Maybe it isn't safe, and we may be able to save him in another way," suggested Bud. "I say, Nort," he called. "Are you hurt?"
How eagerly they all waited for the answer, after the echo of Bud's voice had ceased reverberating in the big cave!
"Yes—I—I'm all right," came the faint answer across the silent pool. "I don't know exactly how I got here. Something hit me on the head—after I fell—fell in. I reckon I must have floated near this rock and—and just naturally grabbed hold and—pulled myself—up!"
"That's enough! Take it easy now!" called Bud. "We're coming over to get you!"
"Sure you're not hurt?" asked Dick, his voice trembling.
"Nothing more than a bump on the head," answered Nort, his own tones stronger now. "Not half as bad as I've gotten at football," and he laughed a little—the most joyful sound any of them had heard since the sweeping away of the boy rancher.
"Well, now we've found him, the next thing is to get him over here," spoke Bud. "Two of us had better swim out there. This water looks to be all right," and he stooped down and tested it with his hand. "As warm as the river," he added.
"I'm going to swim out!" declared Dick, and this time, as he began to "peel," no one stopped him.
"I'll go with you," said Bud. "We'll tie the ropes around our waists and they can hold them here on shore. It will be better than taking a risk, using the old tires," he added, "and, while there isn't any current in the pool now, no telling what may happen."
"Sure you want the ropes," said Old Billee. "But you'd better take a tire for Nort," and they did.
"Hold hard, Nort!" called Dick, as he and Bud took off their clothes in preparation for the swim. "We're coming!"
"I'll hold hard all right," came the answer back across the pool. "And there's something hard here to hold on to, all right."
They did not then realize his meaning, but they understood, later, when they made a most amazing discovery.
In a few minutes Dick and Bud were in the water, lariats held by those on "shore" tied around their waists; and the two boy ranchers were swimming toward the big rock in the middle of the pool. Lanterns at the edge of this strange underground body of water gave sufficient light to enable the swimmers, and the others, to see Nort now standing on the great boulder which emerged from the midst of the black water.
It was the plan of Bud and Dick to help Nort to swim back to where the others stood, they supporting him on either side. For though Nort was a better swimmer than his brother, in his weakened condition, hit on the head as he had said, he might suddenly collapse.
So also might Bud and Dick, or there might suddenly appear a swift current in the now quiet pool—that is, quiet beyond where the stream flowed in—and in that latter event the lariats would serve to pull them all to safety.
"Gee! I thought you were a goner!" gasped Dick, as he climbed out and clasped his brother by the hand.
"I would have been, only that I floated near this rock, and managed, half unconscious as I was, to grab hold of a projection and pull myself up," Nort answered. "That water came up so fast it scared me, and I slipped right into it."
"We saw you," said Bud, sitting down on the rock to get his wind, so he might be at his best in helping Nort on the return journey.
"It was—awful!" spoke Dick simply, and then he made no further reference to his mental agony.
"Well, are you ready to go back?" asked Bud, after a pause, in which interim they had called to those across the pool that the lost lad was all right.
"I'm ready, yes," was Nort's answer. "But I'd sort of like to see what this hard lever-like object is."
"Oh, yes," spoke Dick. "You said you had something hard to hold to. Let's have a look—if we only had a light," he added, for it was quite dark on the great rock in the midst of the black pool. The light of the lanterns did not brightly penetrate that far.
"I have some matches, in a waterproof case, if I didn't lose it out of my pocket," said Nort, feeling in his soaking trousers. "Here they are," he went on a moment later. And as his hands were drier than those of Bud or Dick, Nort opened the box and managed, after one or two failures, to strike a light.
As the little taper flared up the three boys on the rock saw, standing upright about in the centre of the large boulder a great handle, or lever, of copper. The metal gleamed dully red in the flickering light.
"What is it?" asked Bud, as Nort struck another light.
"I don't know," was the answer from Nort. "I discovered it when I was crawling about and feeling around. I thought, if worst came to worst, I could hold to this if the waters rose."
"They seem to be as high as they're going to get," said Bud. "But this sure is queer! Hold your match closer, Nort."
Another of the tapers was lighted, and across the pool came the voice of Snake Purdee, asking what was going on.
"There's some sort of a handle, or lever, here," answered Bud, as he examined it more closely. "It moves, too," he added as he laid his hands on it and pulled it toward him.
"Look out!" cautioned Dick, but it was too late.
Bud had pulled the copper lever toward him, and, in spite of its size and weight, it moved easily in what appeared to be a slot in the rock. It clicked slightly, as though connected with hidden mechanism.
Then, with a suddenness that was startling, a low but ever-increasing roar seemed to fill the cavern in which was the black pool. The roar grew louder and louder, and the very rock beneath their feet seemed to tremble.
"What have you done?" gasped Dick.
"Search me!" answered Bud in such queer tones that Nort laughed.
And then a strange thing happened. As Nort struck another match he and the boys on the rock could see the water all about them beginning to recede. Slowly it flowed at first and then, with a rush, it began running out of the place as fast as it had run in.
"What's up over there?" called the voice of Old Billee from "shore," so to speak. "What you fellers doin' with th' water?"
"I just pulled that lever," sang out Bud.
"Then you've done the trick!" said the old cowboy. "You must have opened some gate, and the water's running away. Better swim over here while you have the chance. When the water comes back that rock may be covered!"
But another strange part of their mysterious adventures was that they did not have to swim back. For the water receded so rapidly that, in a little while, it was possible to wade from the rock to the stone edge of the pool where the other members of the party stood. And wade back to their friends Bud, Dick and Nort did.
"Oh, boy! But we're glad to see you!" cried Old Billee, as he caught Nort by the hand.
"You let out a mouthful that time!" declared Yellin' Kid, and his voice nearly split their ear drums, so magnified was it by the echoing, vaulted roof of the cavern.
"But what all happened?" asked Snake Purdee. "Is there some old Mexican grain mill under here that has a water-wheel, sluices and gates?"
"I give it up," answered Bud. "All I know is that I pulled that copper lever—and it's copper so it won't rust off, I reckon—and the water began to rush out as fast as it must have come in here."
"It is mighty queer," agreed Old Billee. "Let's go take a look," and he started to walk across the intervening space between shore and the great rock—a space in which only a few puddles of water now remained.
"Will it be safe?" asked Bud, who had begun to dress, an example followed by Dick.
"Why not?" asked Old Billee. "The water can't rise any higher than it was when you fellows were on the rock. An', according to your tell, there's room enough for us all t' stand there."
"Yes, it's big enough," agreed Bud. "But suppose we all get there, and the water begins to come back?"
"We'll turn it loose again with th' lever," answered the old cow puncher. "But I reckon it can't fill up this pool again until that lever is shifted hack where it was before you yanked it."
"Maybe not," admitted Bud. "Well, let's take a chance. If worst comes to worst we can swim back, and I'd like to solve this mystery. I feel that we're getting at it now!"
"That's right," said Nort, who was feeling stronger every moment. "When I fell in, and was carried away," he said, "I had a wild notion that this might lead to the discovery of something. I managed to keep my head out of water as I was swept along, until I got a knock on the noodle, and that put me partly to sleep. That may have been a good thing, too, for they say a partly unconscious person doesn't breathe much, and that's why I didn't swallow any water to speak of.
"I was dazed when I must have been swept, or floated, past that rock but I came to in time to save myself. Gosh! but I was glad to hear you yell though, Dick!" he said.
"Well, let's get over there an' start pryin' out this secret," suggested Old Billee. "This is gettin' mighty interestin'!"
It seemed reasonable to suppose that the water would rise to no greater height than it had when the searchers had discovered Nort on the rock. And as this boulder was well out of water, and large enough for them all to stand on, they would run no risk, even if the flood should start to return when they were in the middle of the pool, which, however, was a pool no longer, but merely a wet reservoir, so to speak.
"But I don't believe the water will flow back here until you shift that lever again, Bud," declared the old ranchman. "And I'm going to have a try at it!"
"Isn't it takin' a chance?" asked Snake.
"You got t' take chances in this world!" declared Old Billee.
"Well, let's go!" suggested Bud.
"I think I'll stay here," spoke Nort. "I don't feel quite up to walking over those rocks. And you may need some one on this side who can throw a rope," he added, as he looked at the lariats.
"All right," assented Bud. "You stay here, Nort."
They left him on the shore, as I call the rocky edge of the pool, with a lantern, and, taking other lanterns with them, the little party set out. It took them only about three minutes to walk across to the great rock, which stood upright in the middle of the cavern floor.
Rising up in almost the very centre was the heavy, copper lever. By the light of the lanterns it was examined, and seen to extend down through the rock, whither no one knew.
"It works a water gate all right," declared Old Billee. "Let's pull it back to where you found it, Bud, and see what happens."
It was with some feelings of apprehension that the others watched as Old Billee reached for the copper lever and pulled it toward him, It operated as easily as it had for Bud.
And almost as quickly as had taken place on the other occasion, there was that roaring, rumbling sound, a noise as of the blowing of a great wind, and then the waters began to rush back into the pool.
"Here they come!" yelled Dick, as he stood beside Bud on the rock.
Truly the waters were returning as the hidden gate was closed when Billee pulled the lever.
Would they go down again?
That was what each one asked himself.
Rapidly rushing, foaming, bubbling and boiling, the waters rushed into the mysterious cavern, until they again filled the pool across which Bud and Dick had swam to the rescue of Nort on the rock. Now the situation was reversed. It was Nort who was on the mainland, or shore, so to speak, and the others who were on the rock.
But it was one of their own choosing, in an endeavor to solve the mystery, though as Bud and his companions watched the waters creeping higher and higher up the surface of the rock on which they stood, their hearts were not altogether easy.
"Suppose it covers the rock?" asked Dick.
"Then we'll have to swim back where Nort is," Bud answered.
"Shucks! You won't have to do nothin' of the sort!" declared Old Billee stoutly. "She won't come up any farther than it did before!"
And he was right. When the water around the rock lapped the erosion mark, which had been worn in the hard stone by centuries of the flow of the fluid, the flood ceased. The roaring, bubbling and seething, like that which takes place in a canal lock, came to an end, and the water of the pool became quiet.
"There! What'd I tell you?" cried Old Billee. "I closed th' water gate, that Bud opened to let th' water out, an' she come back. Now all we have t' do, so we can walk back, is t' yank this lever again."
"Does it only work two ways?" asked Yellin' Kid, his voice again softened, as the mystery of the place seemed to cast a shadow over him and the others.
"Seems to," Bud answered, holding his lantern down close to where the copper handle entered the rock.
There appeared to be a slot cut in the hard stone—a slot about three inches wide, and a foot long, in which the copper lever could be moved backward and forward, but not from side to side.
"Let's try the other way, now," suggested Dick.
Once again Old Billee pulled on the copper shaft, which, as they could see by the light of all their lanterns combined, seemed to have been rudely hammered out, for it bore the rough marks of a primitive forge.
And no sooner had the lever been pulled to its limit in the slot than there sounded again the rushing, roaring tumult of noises, and, after a little, the water began receding once more.
"We've discovered the secret!" cried Dick.
"No, only part of it," said Bud. "We've got to find where the water goes, and if pulling this lever sends it into our reservoir. That's the main thing to discover."
"But we're on the track of part of it," went on Dick. "I wonder who built this secret water gate, and the lever that operates it?"
"It may be part of the work of the ancient Mexicans, the old Indians or the Aztecs, who inhabited this land ages ago," said Bud. "Copper will last almost forever, you know, even in water, as it doesn't rust. And you've read how the ancient Aztecs used to build great vaults under the mountain, and arrange to flood them to keep their gold away from the Spaniards."
"Yes, I've read of that," admitted Dick.
"Say, where can you get a book like that?" demanded Old Billee.
"I've got one at the camp," Bud answered. "I'll let you take it. Of course my theory may be all wrong," he went on. "But I begin to believe we've stumbled on some ancient Aztec water system."
"You don't mean to say those old Mexicans, for that's what the Aztecs were, are still hanging around in this cave, turning your water on and off, do you?" demanded Dick.
"No, it's some one more modern who's making trouble for us," Bud declared. "But we're on the track of a big discovery, I believe. Look, the water is almost gone!"
This was true. The pool was emptying itself as it had done before, and, in a short time they could walk back to where Nort awaited them.
"What's the next thing to do?" asked Dick.
"Get back where we left our grub and feed our faces," suggested Snake Purdee.
"Yes, I think that will be best," Bud said. "Then we can talk over the next move. I begin to feel hungry."
"I hope we won't be disappointed," remarked Yellin' Kid and his vocal powers seemed to be on the mend, for he called loudly.
"Disappointed? How?" asked Old Billee.
"I mean I hope we find our grub where we left it," Kid explained.
"Why wouldn't it be there?" Old Billee wanted to know. "Do you think them Hatchet-texts have sneaked in and took it?"
"You mean Aztecs?" laughed Yellin' Kid. "No, I wasn't referrin' to them. I mean I hope our monkeyin' with that copper handle didn't send the flood over the place where we left our things."
"I never thought of that," said Bud. "By Zip Foster! I hope nothing like thathashappened!"
With anxious hearts they hastened back to the place where Nort had been swept away. They had left the strange lever set to drain the pool, and what state of affairs they would find on returning to their point of digression no one could say.
"Maybe we'll find the water running on into Flume Valley," suggested Nort, who seemed to be almost himself again, except for a feeling of weakness.
"I hope so," spoke Bud.
But this was not the case. On reaching the place where the tunnel branched, they found no water there at all. None was running in the main channel, and none was turning off down the "stem of the T," to use the illustration I first employed.
"Keeps on being strange, doesn't it!" said Bud.
They all agreed with him.
"What's the next move?" asked Dick, as they gazed about, finding their food and supplies safe, and no water, to mention, anywhere about.
"Let's grub!" suggested Snake.
"And make a fire and heat the coffee," urged Bud. "I don't believe the smoke will do any harm, and there's plenty of dry driftwood in the higher places, and on little ledges."
"Some hot coffee would go down mighty well!" remarked Nort.
"Then you're going to have it!" asserted his cousin. They had brought some of the cold beverage along in tin flasks, and these were soon heating over a little blaze that was kindled along the bank of the underground stream that was again dry.
The food and hot drink put new hearts into all of them, especially Nort, and when appetites were appeased they gathered about the cheerful, if small, blaze, which gave off scarcely any smoke, and held a discussion.
"What I think we had better do," said Bud, "is to travel on until we come to the place—if such a place there is—where this stream again shunts off to the side. For I'm sure there is such a place if we find that the water is running into the tunnel from the river."
"We can't be sure of that, though," Old Billee said.
"No, but we can find out when we get to the other end of the tunnel," declared Bud. "My idea is—though, of course, I might be wrong—that there are two side passages, so to speak. Sometimes the water branches off the main channel and fills the pool where we found Nort on the rock. Then it may flow down another channel, farther on, but nearer to the river end of the tunnel."
"But if the water came along the main channel, until it got here, and then filled the pool to the limit, as was evidently the case," suggested Nort, "why wouldn't the water then back up and go on to our reservoir—and it didn't do that."
"There may be some outlet from that pool and cavern where we were," said Bud.
They considered this for a moment, and agreed that he might be right.
"Then what we've got to look for," went on Bud, "is another side passage where the water is shunted off, that is, providing it is not cut off at the river pipe. And if there is such a passage it must be on the right-hand side of the stream, as was the one where Nort fell in. For we went all along the left-hand bank the other time, and didn't discover anything."
"And suppose we find the second branch stream now—what will we do?" asked Snake.
"Two of us will come back and work the lever, while the others stay at the second stream to see what happens," was Bud's answer. "Come on; let's go!"
They put out the fire, packed their belongings, and, making sure that Nort was able to travel, they set out again. Nort's garments were soaking wet, or, rather, they had been, but there was a current of warm air in the tunnel, and soon he began to dry out, for which he was very thankful.
They found the second branching stream sooner than they expected. It was less than a quarter of a mile from the first, or the one into which Nort had fallen, and it was almost of exactly the same character.
"Look out! Here it is!" cried Bud who saw it first, his lantern gleaming on the swiftly-rushing water. "Go easy!"
And "easy" they went, reaching the edge of the ledge below which flowed the mysterious, powerful current.
"We can go along here, just as we did before. Here's another branch tunnel!" announced Dick, holding up his lantern, and showing a wide, high passage, the bottom and middle part of which was occupied by the stream.
"I wonder how many of them there are?" remarked Nort as he and the others turned into the black opening, which seemed to slope as though descending a hill. This gave greater force to this stream of water.
"And I wonder if it also runs into a cavern, with a rock and a copper lever in the middle!" voiced Dick.
"Hope we find out soon," spoke Bud. "This is getting more and more queer all the while."
They tramped on in the blackness that was relieved only by their swaying lanterns. They walked beside the strange, underground stream, and they had progressed farther than along the other branching body of water when Old Billee, who was ahead just then, suddenly halted and uttered a warning.
"Listen!"
"What is it?" asked Yellin' Kid, in his usual tones, but Billee reached back and gave him such a dig in the ribs that Kid subsided with a grunt.
"I hear talkin'!" whispered Billee. "Voices! There's some one else in this place than us! Listen!"
They stopped and strained their sense of hearing. And then, above the slithering murmur of the water, they all distinctly heard a voice say:
"I think we've fixed 'em this time! They won't steal any more water from Pocut River!"
The boy ranchers looked at each other.
"Del Pinzo!" whispered Nort.
"As sure as Zip Foster ever ate ham and eggs!" agreed Bud.
"Hush!" begged Old Billee.
And as they became quiet again they heard another voice say:
"I guess it's all up with 'em now. We might as well light out and touch off the fuse!"
"Whew!" softly whistled Bud.
Together the party of searchers moved softly forward. Suddenly the passage along the bank of the mysterious stream turned sharply, almost at a right angle.
And there, in what appeared to be a small cave, excavation or cavern, high in the upper wall was disclosed a roughly circular opening, like a window or port hole. Through this port hole a light showed, and outlined in the light were several rough-appearing men, leaning together over what might have been a table.
"Del Pinzo!" murmured Dick.
"Conspirators!" exclaimed Bud. "They're the ones that's been turning this water on and off! We're on the track of the mystery now!"
Whether he spoke loudly enough to be heard, or whether some other sound made by the searchers alarmed the men in the upper niche, was not disclosed just then.
But the light suddenly went out, and confused sounds followed.
And chief among these sounds was the rushing, roaring noise, the blowing as of a mighty wind, and the water near the boy ranchers and their companions was strangely agitated.