"I wonder what the matter is," said Mrs. Bunker, when she heard Russ shout.

She did not have to wonder long. As the others drew nearer, Russ shouted again, and this time he said:

"The water's all running out of the spring! It's going dry, just like Uncle Fred said it would!"

"More mystery!" exclaimed the ranchman as he hurried on.

The five little Bunkers and the grown folk reached the edge of the big spring where Russ stood. He was looking down into the clear water, and the others did the same.

"Surely enough, it is getting lower!" exclaimed Mother Bunker.

"There isn't half as much in as there was at first," added her husband. "Is this the way it always does, Fred?"

"I never saw it run out before," answered the owner of Three Star Ranch. "Every time before, it has happened in the night when no one was near it. We'd visit the spring in the evening, and it would be all right. In the morning it would be nearly dry, and it might stay that way a day or two before the water came back into it. Very queer, I call it."

"So do I!" exclaimed Daddy Bunker. "I'll take another picture of it now. Maybe that will help us solve the mystery."

While he was getting the camera ready Mrs. Bunker said:

"The water is going out fast. You'd better get a drink now, Russ dear, if you want it, for there may not be any more for a long time."

"I will!" exclaimed Russ.

Uncle Fred kept half a cocoanut shell tied by a string near the spring to use as a cup. This Russ dipped in the fast lowering water, and got a drink for the other little Bunkers and for himself, as they all seemed to be thirsty at once.

"What will you do for water when the spring runs dry?" asked Mrs. Bunker of her brother.

"We'll have to draw some from the creek, but I have a lot of this water stored in the tank. I always keep that full lately, since I can't tell when my spring is going dry."

They stood and watched the water going out of the spring. It was just like it is when you pull the stopper out of the bathtub. The water gets lower and lower, running down the pipe. Only, of course, there was no pipe in the spring—that is, as far as Uncle Fred knew.

"The water seems just to stop running in," said Daddy Bunker, as he knelt down and looked more closely at the little hill of rocks back of the water hole. It was from cracks in these rocks that the water bubbled out and filled a hollow, rock basin before flowing on. Now less and less was coming and, of course, as the spring water always kept running away, or it would have overflowed, the basin was slowly but surely getting dry.

"I think what is happening," said Daddy Bunker, "is that, somewhere back in the mountains or hills, where the stream comes from that feeds this spring, the water is being shut off, just as we shut off the water at the kitchen sink faucet. Where does the water come from, Fred?"

"I don't know," was the answer. "It must come from some place underground, as we've never been able to find it on top. Well, we won't go thirsty, for there is plenty of water in the tank. But I hope the spring soon fills up again."

Even as they watched the water got lower and lower, until there was hardly a pailful left in the rock basin. No more clear, sparkling water bubbled up out of the cracks in the rocks. The strange thing that Uncle Fred had told about was happening at the spring.

"Is the cows drinking up all the water?" asked Mun Bun, as he looked into the now almost emptied basin.

"No, I don't believe they are," answered his uncle.

"Maybe the Indians took it to wash in," said Margy. "The Indians wash, doesn't they, Uncle Fred?"

"Well, maybe some of 'em do, but not very often," was the answer. "They're not very fond of water, I'm sorry to say. But there! we won't worry about this any more. You six little Bunkers came here to have fun, and not bother about my spring. Daddy and I will try to find out why the water runs away, and stop the leak. Did you all get drinks? If you did we'll go back to the house. It must be almost dinner time."

They all had had enough to drink for the time being, and, leaving the spring, which was now only a damp hole in the ground, the party went back to the ranch house. Captain Roy met them.

"Spring's gone dry again," said Uncle Fred.

"Again! That's too bad! I was hoping we'd seen the last of that. Well, now, we may expect some more bad news."

"What kind?" asked Mrs. Bunker.

"Oh, the captain means about losing more cattle," answered Uncle Fred. "Almost always, when the spring goes dry, it isn't long before some of the cowboys come in to tell about our cattle being taken away. But maybe that won't happen this time."

After dinner the six little Bunkers started to have some fun. Mun Bun and Margy went to have their afternoon naps, but Rose and Violet took their Japanese dolls, which had been unpacked, and found a shady place on the porch where they could play.

"What are you going to do, Russ?" asked Laddie, as he saw his brother with some sticks.

"I'm going to make a tent," was the answer. "We can make a tent and live in it same as the Indians do. It's more fun to live in a tent than in a house when you're out West."

"Oh, yes!" cried Laddie. "I'll help you. But where can we get the cloth part?"

"Well, I got the sticks," Russ went on. "I guess Uncle Fred will let us take a sheet off the bed for the cloth part."

But the boys did not make the tent that day. Just as they were thinking about going to ask for the cloth Uncle Fred called:

"Come on, Russ and Laddie, and you, too, Rose and Vi. We're going to look at the ponies. I started to take you to them when we found the spring was going dry, and that made me forget. Now we'll go."

"Oh, what fun!" cried Russ.

"Dandy!" exclaimed Laddie.

"I love to ride a pony!" added Rose.

"So do I!" ejaculated Violet.

Uncle Fred led the children to a small corral, which they had not seen before. In it were a number of Shetland ponies, some no larger than big Newfoundland dogs. And some of the ponies came to the fence to be petted as soon as they saw Uncle Fred.

"Oh, aren't they cute!" exclaimed Rose.

"I'd like to ride that black one!" shouted Laddie.

"He's a little too wild," said Uncle Fred. "Better try one of the more gentle ones first. I'll get the men to saddle 'em for you."

In a little while the four little Bunkers were riding about on the backs of four gentle ponies. The little animals seemed to know children were on their backs, and they did not run fast, nor kick up their heels.

Rose and Russ could soon manage their ponies by themselves, but as Vi and Laddie were younger Uncle Fred and one of his cowboys led their ponies about by the bridle. The children rode in a big field, with a fence all around it.

"Now I'm going to ride fast!" cried Russ as he took a tighter hold of the reins and shook his feet in the stirrups. "Gid-dap!" he called to his pony. "Go fast!"

Maybe the pony was surprised at this. Anyhow, he started to gallop. Now Russ was not as good a horseman as he supposed, and the first he knew he had slipped from the saddle and fallen off.

"There you go!" cried Uncle Fred, as he left the pony on which Vi was riding and ran to help Russ.

Russ had fallen in a bunch of soft grass, so he was not hurt; and the pony, after trotting around in a circle, stood still and began to eat grass.

"I wouldn't try to ride fast yet a while," said Uncle Fred. "Better learn more about the ponies first. You can have just as much fun riding slowly, and then you won't tumble off."

"I won't go fast any more," said Russ, as his uncle helped him back into the saddle. The other children did not have any accidents, and rode around on the ponies for some time. Then Mun Bun and Margy awakened from their naps, and they, too, wanted rides. Their father and mother held them on the backs of two small ponies, and walked with them about the grassy field, so that all six little Bunkers had pony rides that day.

"And may we ride to-morrow?" asked Laddie when it was time to go back to the house.

"Yes," promised his uncle, "to-morrow we may all take a ride over the plain."

"Goody!" exclaimed Violet.

"Will mother come, too?" asked Rose.

"No, indeed!" laughed Mrs. Bunker. "I don't know how to ride pony-back, and I'm not going to learn now. You children can go."

"That's what we'll do then," said Uncle Fred. "Daddy and I will take Rose and Vi and Laddie and Russ for a ride over the plain. We'll go and see if we can find where our spring water comes from, and why it shuts itself off in that queer way."

The children waved good-bye to the ponies, and went back to the house. On the broad, shady porch stood Captain Roy. He was waiting for Uncle Fred, and there was a worried look on the old soldier's face.

"What's the matter?" asked the ranchman of his partner.

"More bad news," was the answer. "One of the cowboys just rode in to tell me that some more of the cattle have been taken."

"I might have known it!" cried Uncle Fred. "When the spring goes dry other bad news is sure to come in!"