"Break the dam!" murmured Dave. Yet his eyes sparkled at the thought. "Yes," assented the irrigation engineer. "But we can't do that," objected Mr. Carson. "It's on Molick's land, and if we go there, and start something, he'll fight us. He is a desperate man." "And so ought you to be with your cattle dying of thirst," said Mr. Bellmore. "I am, but--" "There aren't any buts about it," declared the other. "This is a desperate situation, and we'll have to meet it desperately. Morally, right is on your side, and I think it is legally, too. I've been looking into the records and titles of lands along this Rolling River and I find that you have not received all the water rights that belong to you, Mr. Carson. On the other hand Molick has taken more than his share. "And there is no doubt that he had no right to build the dam in the way he has. He should have let some water come down to you. Now the only way to accomplish this is to make a breach in the dam. This will let your cattle drink." "But if we do that--break the dam--he'll either fight us to prevent it, or he'll build it up again," Dave said. "He may fight, but I doubt it. He was warned once before that he was exceeding his property rights, and he can't claim ignorance now. And while it is true that he may build the dam over again, after we cut through it, I don't so much care for that." "A change will have to be made anyhow, but if you can get a little water, temporarily, to your cattle it will save them, and you can drive them to other ranges." "Yes, I could do that," admitted the ranch-man. "Then on to the dam!" cried the engineer, turning his horse as he spoke. "Hurrah!" exclaimed Dave. "That's the way to talk!" Urged on by the thought of the suffering cattle, the three made good speed to the place where the river turned. There, as Mr. Carson had seen a short time before, was the newly-built dam. A number of cowboys were about it, and Dave saw Len, his enemy. "Are you game?" asked the engineer. "I am!" exclaimed the ranchman. Dave said nothing, but there was a flash in his eyes as he nodded his head that told more than mere words. "You and I will go up and have a talk with them," suggested Mr. Bellmore. "Meanwhile Dave can ride and get some of your men, Mr. Carson. We'll need help if it comes to a fight, though I hope it won't. We'll make a formal protest first. Hurry, Dave, every minute may mean a steer's life." Dave whirled his steed about and rode hard and straight for the nearest range where some of the Bar U men were guarding the cattle. Meanwhile Mr. Carson and the engineer crossed the stream below the dam, and rode toward the Centre O boys. "Well, what do you want?" surlily demanded the young heir of the house of Molick. "This is private land, and no trespassers are wanted. Get off!" he snarled. "We came on business," said Mr. Carson. "Where's your father?" "I don't know. But he told me if you came on this land to order you off, and that's what I do!"