“I believe nothing but human beings would have so scared that grey rascal. My! how he ran! I didn’t think of it at the time. I was too excited,” Chet said reflectively. “But take it from me, boy, that wolf was running from man.” “I don’t understand it,” declared Dig. “If there had been another party besides us stalking that herd, why didn’t we see them?” “They wouldn’t have been very good hunters if we had seen them,” laughed Chet. “I mean after the buffaloes were stampeded. They must have been in that thicket out of which the wolf came.” “Sure. And the very fact we didn’t see them after the stampede, makes me suspicious,” Chet returned. “I tell you, Dig, that party that stopped on the trail and robbed us last night puzzles me greatly.” “How so?” “They left the trail somewhere this side of our last camp; but I couldn’t see where. They were careful to hide their tracks.” “I reckon, considering that they had robbed us.” “Well, that might be so, too,” ruminated Chet. He did not want to frighten his chum regarding Tony Traddles and the strange man whom Amoshee had said were on the trail behind them. Yet the thought of the pair of rascals stuck in Chet’s mind and dove-tailed into the mystery of the two who had stopped to rob their camp. “Well,” Dig said finally, “I suppose we’ll have to do as you say—keep watch. But we haven’t seen anything of any prowlers and it is likely those fellows who troubled us before are a long way from here.” “Hope so,” agreed Chet. “But we’d better be sure than sorry.” The boys were tired after the activities of the day; but Dig insisted upon standing the first watch. “And believe me!” he said, “I shall march up and down all the time. No sleeping on post this trick!” Thus dividing the vigil, Chet bade him good-night and rolled up in his blanket. It was a warm night, however, and later, after he was dead asleep, the boy kicked the blanket off. Dig kept away from him, however. There was no sound of roaming animals of any kind at first, and the watchman did not consider it necessary to feed the dying fire. The stars rendered a faint light and he could see objects in outline quite plainly. The horses fed near the camp, and the ripping sound of the grass as their strong teeth severed it from the roots was the only sound Dig apprehended for some time. It was as quiet here at this water-hole in the great plain as it would have been in Dig’s back yard. There was not even the rustle of a breeze in the brakes. Dig tramped back and forth along the edge of the pool, occasionally stooping down to peer through the dusk at the horses. He could see them better that way. He kept away from his sleeping chum and their outfit purposely. He did not propose to rouse Chet until it was full midnight.