"Senor, it is true," spoke up another. "I was a guard at the time." Adrian could scarcely believe the statement, but he afterward learned that the men spoke the truth. "Well, then," he said, "we had better look to our arms, for we may need them. There is no knowing how this affair has turned out." The advice was well taken, for as they drew near the scene of the wreck, they saw that they were badly needed. More than a dozen horsemen were in sight at some distance from the wreck and with their long-range rifles were doing their best to pick off any one who showed his head. "Our party must be out of ammunition," suggested Adrian, "or they would give a better account of themselves." "Our carbines would not carry that far," explained one of the guards. "Our Marlins will," replied Adrian, and as he spoke there were two simultaneous flashes from two of the car windows and two of the bandits fell, one shot from his horse and the other with his horse shot under him. For a moment the other horsemen hesitated as to the course they should pursue and then, putting spurs to their horses, they dashed toward the train, just as the express car, having reached the end of the track, bumped onto the ties and came to a stop. "Now!" cried Adrian as the riders drew near, firing as they came, and four shots rang out. The volley from so unexpected a quarter took the horsemen completely by surprise, and they pulled up with a jerk. The action proved their undoing, for as they stood thus for a moment, they gave those in the train the opportunity they desired and the volley that followed turned four more riderless horses upon the plain. It was more than flesh and blood could stand, and the seven or eight remaining horsemen turned and fled, followed by at least three whistling bullets from as many Marlins. The fight was over and the bullion had been saved, but what of Broncho Billie, who had been left at the top of the hill four miles away? That was the first question asked by Donald when he greeted Adrian two minutes later. "Oh, he's all right," was the laughing reply. "He's just taking a little walk for his health." But when Billie failed to put in an appearance an hour later, the boys mounted their horses and started up the track to meet him, leading Billie's mount between them. CHAPTER III. BILLIE LOSES HIS NERVE. Broncho Billie was not a rapid walker. In fact, if there was any one thing in which Billie was not a success, it was walking. He could ride a horse all day, but when it came to depending upon his own legs as a means of locomotion, he was a dead failure. Therefore he walked slowly along, counting the ties as he went. "They certainly do lay 'em thick," he mused after some minutes. "Three hundred and one, three hundred and two, three hundred and three, three hundred and four, three hun----" He stopped short and looked behind him. "I sure thought I heard some one," he muttered. "It must have been a bird." He turned and started forward.