When they reached there they dismounted, hitched their horses in the timber and started down the line on foot. They found the cowboys that they had stationed along the line in their respective places. They were very prompt in exchanging signals, and they spoke in whispers so that their voices might not be overheard. By and by in the starlight they saw about a score of cattle going through the grass as though they were being driven by somebody. Fred and Terry crouched down in the grass and watched them. They both became fully satisfied that some one was driving them, and they ran along with the cattle in order to ascertain where they were going, and why. They were very near the corner of the fence, for, as the reader doubtless remembers, they had enclosed only twenty of the forty thousand acres, as they thought that was about as much as they would have need for inside of the next two years. Suddenly Terry tapped Fred on the shoulder and whispered: "Down, Fred," and Fred dropped down on his knees. Terry motioned with his hand and pointed out on his right where they could both see the figures of two men moving cautiously and closely behind the cattle, and they both wondered if another panel of the wire had not been cut just ahead of them. Suddenly one of the cattle turned in their direction, and one of the men ran around to head him off. He ran almost over Fred, who sprang up and dealt him a blow on the side of his head that caused him to sink down unconscious. CHAPTER VIII. FRED AND TERRY CAPTURE CATTLE THIEVES. Terry heard the blow that Fred gave the cattle thief and he knew what it meant, for the fellow sank down without uttering a word. The thief's pal, seeing that the cow that had strayed off was not being turned around, went to the assistance of his confederate and he ran up against Terry. Terry rose up and gave him a crack on the head with his heavy revolver. He saw more stars than he probably ever thought had a home in the skies, and down he dropped. "Now, Terry," whispered Fred, "let's see if there are any more of them," and as quick as possible they bound the two unconscious thieves hands and feet and continued to follow the cattle. They walked straight up on their feet, knowing that the confederates, if there were any, would mistake them for their pals if they saw them. After a few minutes they saw two other fellows advancing toward them, and one of them came up to Fred and asked in a low tone of voice: "What's the matter?" "Only this," said Fred, smashing him in the face with his revolver and sending him tumbling over in the grass. The other fellow stopped and, suspecting something wrong, started to run. "Halt!" said Terry, "or you're a dead man." The fellow threw himself down in the grass and tried to run on his hands and knees and thus escape any bullet that might be flied at him, but Terry was on him in a moment and gave him a terrible crack with his revolver on his head.