"I don't want to let him manipulate that light enough to send any signals to possible Mexican watchers, Overton." "I was just thinking of something of the sort, sir," Hal smiled. "And there's another puzzle in my mind. Have you any idea, sir, how these Mexicans got the cases out of Guarez's barn in spite of your guard at that point?" "The cases didn't come from Guarez's barn," replied Captain Foster, with a laugh. "Do you begin to see light, Mr. Overton?" "I believe I do, sir," muttered Lieutenant Hal. "The cases in Guarez's barn, it may be, are only dummies, put there with a good deal of display, so that if troops came their commander would be sure to hear about them. The Mexicans probably imagined that, after an American military commander came here, heard the gossip about boxes in Guarez's barn, and then guarded that barn, that the commander would then feel that all needed precautions had been taken. That was Mexican craft, but Guarez failed to understand that he was dealing with American thoroughness." "That was about the size of the shallow trick the Mexicans tried on us," laughed Captain Foster. "Are you going to send these cases ashore, sir?" "Not until daylight. We must not forget that there may be another expedition attempted at some other point. Mr. Overton, I begin to think that this may be the point chosen for the shipment of arms enough for fitting out a whole rebel army in Mexico. I think I will go back to camp, now, and question Guarez. I may find him in a mood to talk." "And my orders, sir?" "Make this boat your headquarters. Do not leave here until I return, Mr. Overton." "Very good, sir." "It was a pretty slick way that you caught us," began the mate, lounging near Hal as he stood on deck. "Then you admit that this boat was engaged in an attempt at smuggling arms over the border?" demanded the young lieutenant, wheeling quickly. "What's the use of denying it," questioned the mate, "with such cargo as we have?" "Very little use indeed," Hal rejoined. "How much were you to get as your share of the night's work?" "Oho! I didn't say that I had even a suspicion of what the game was," retorted the mate coolly. "I could only suspect, at best. You can't trap me into saying anything that would send me along to share Captain Boggs's fate." "You're smooth enough," nodded Lieutenant Overton, "but don't try to play any further tricks." "With United States troops aboard? What do you take me for?" grumbled the mate. Hal didn't feel much inclined to talk with the fellow, so he stepped forward, leaving the mate by himself. Half an hour passed. Truth to tell, the young Army officer felt the monotony of his present position, confined to the boat and the pier. Passing the sentry at the gang-plank, who stood at present arms in salute, Hal Overton walked forward to the outer end of the pier. He had stood there some ten minutes, when, two or three miles up the river, he thought he saw a brief flash.