"No run!" answered Buck Tooth briefly. "All gone!"

"More trouble!" commented Bud. And then, with a grim tightening of his lips, he added: "This time we'll get to the bottom of the mystery!"

There was no doubt about the fact that the water had stopped running.

As they all raced up the sloping side of the reservoir they saw only a few drops trickling from the pipe.

"The third time--I'm going to make it the last if it's possible,"

declared Bud.

"What yo' aimin' t' do?" asked Old Billee.

"Go through the tunnel from end to end, and both sides, and see where the water vanished to," was the answer. "We'll get up a regular expedition this time, and maybe take a boat. We'll find out what it all means."

"I believe you're right," a.s.serted Snake Purdee. "There's no use trying to work Flume Valley if the water supply is goin' to be cut off without notice. I'm with you, Bud!"

"So 'm I!" shouted Yellin' Kid. "Whoop-ee! I'm a lone wolf an' this is my turn for makin' a noise! Whoopee!"

"Let's find out, first, if the water is coming into the pipe from the river," suggested Nort.

"You call up," begged Bud. "I'm going to get ready for this expedition. We'll have to start in the dark," he went on, referring to the black tunnel that stretched under Snake Mountain. "But we may come out into the light. Anyhow, we're going in!"

CHAPTER XX

INTO THE DEPTHS

Preparations for exploring the mysterious tunnel on this occasion were much more complete and elaborate than when Bud, d.i.c.k 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 d.i.c.k.

"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 d.i.c.k. "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 d.i.c.k.

"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 pa.s.sage."

"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 d.i.c.k, 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 d.i.c.k.

"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.