"It's an attack! That's what it is!" cried the senator's son. "I'll bet some of those Mexican bandits are coming over here! Oh, Dave! what do you suppose we had better do?" "I don't know, except that we had better slip on our clothing and get our pistols," answered Dave. "This looks as if it might be serious." "Up, boys! Up!" came the cry from somebody outside. "Get your guns and your pistols! The Mexican raiders are coming this way!" CHAPTER XXV THE MEXICAN RAIDERS By the time the two chums had hastily donned their clothing and possessed themselves of the pistols they had purchased in San Antonio on the advice of Mr. Watson, the camp was in confusion from end to end, with the various bosses shouting orders and the men themselves wanting to know what the trouble was and what they had better do. "It's some of those confounded greasers!" cried Frank Andrews, as he, too, arose and armed himself. He had a repeating rifle, and it was known to Dave and Roger that he was an exceptionally good shot. Andrews led the way from the building, followed by our hero and Roger and several others. In the meantime, the distant shouting and shooting seemed to have moved farther westward, in the direction where the new Catalco bridge was being constructed. "It can't be their intention to blow up the bridge?" queried Roger. There had been talk of this several times. "No telling what those rascals are up to," answered Frank Andrews. "This may be only a rumpus kicked up to cover a cattle raid or something like that." In the midst of the excitement the telephone in the main office began to ring and was answered by one of the clerks. A few minutes later he came rushing out to where Mr. Obray stood talking to his assistant and the boss of the construction camp. "Just got a telephone from the Tolman ranch," announced the clerk. "Old man Tolman said they had been raided and that half of the raiders were coming this way. I tried to get some details from him, but in the midst of the talk I was shut off. I suppose somebody cut the wire." "I thought that might be it," answered the head of the engineering corps. "We ought to help Tolman all we can," announced the boss of the construction camp. "He promised to assist us in case we had any trouble, and turn about is fair play." "Right you are, Peterson, and any man who wants to go out can do it." And word was passed around to this effect. Dave and Roger listened to this talk and what followed with much interest. In less than five minutes over thirty men from the construction camp had signified their willingness to go after the raiders, and these men were joined by Frank Andrews and three other civil engineers, all well armed and mounted. "I'd like to join that crowd and go after those Mexicans!" exclaimed Dave, his eyes sparkling. "So would I!" returned the senator's son, quickly. "Those fellows can't be anything but plain bandits and cattle thieves."