"But the drift will carry us downstream."

"If we get too far down we'll steam back. Mate!"

"Aye, aye, sir," answered the man standing beside the tug's master.

"Get your masthead light out. Then display your starboard and port sidelights. Men," called Hal to his soldiers, "I call upon you to note and remember that this craft had no lights out until I ordered them out."

"We don't need lights out at the pier," growled Boggs, comprehending the meaning of Lieutenant Overton's remark.

"I believe you do," Hal rejoined, "when you are about to leave the pier for the stream. However, that's a point for higher authority than yours or mine to determine."

The mate soon had the running lights properly displayed and returned to the wheel-house.

Very slowly the boat drifted downstream. After fifteen minutes Hal directed that the skipper take his boat far enough upstream to make up for the drift.

From time to time the Army boy turned his gaze toward the pier. Hal had no need to bother himself with discipline aboard. All the crew and the Mexicans were confined where they could be watched, for the two deckhands were Mexicans, and had been driven in with the others. Five of Uncle Sam's soldiers were enough to keep the prize safe.

Lieutenant Overton was beginning to grow impatient when he saw a squad of troops, as he judged them to be in the darkness, march out on to the pier. Then the voice of Captain Foster hailed:

"Lieutenant Overton!"

"Here, sir."

"Bring that tug in."

"Very good, sir."

Hal gave the order to Captain Boggs, who sulkily obeyed. The mate was permitted to go aft and to bring two swarthy deckhands out where he could use them.

The boat was soon berthed, and hawsers made fast. Without waiting for the gang-plank to be placed Captain Foster sprang aboard, grasping his "youngster's" hand.

"Fine work, Mr. Overton!" commended the captain heartily.

"It came near being very bad work, sir."

"So I've gained from what Simms has told me on the way down here. But you showed the real commander, Mr. Overton, in your ability to extricate yourself from a bad mess and turn it into victory."

Captain Foster had brought with him a sergeant and ten men. There were now enough soldiers to post so that there need be no fear of any of the prisoners being able to escape.

"Sergeant, have two of the cases brought ash.o.r.e," directed Captain Foster. "And open them."

Some of the cases were on the deck forward. Others had been dropped into a small hold forward.

The cases opened proved to contain rifles, ten to a case. Some smaller boxes from the hold were found to hold cartridges to fit the rifles.

"A very bad business for you, Boggs," remarked Captain Foster.

"Why is it?" demanded Boggs gruffly.

"You were going to smuggle these arms and supplies into Mexico, across the river."

"Where's your proof?" demanded the tug's master cunningly.

"Our Mexican prisoners are proof enough," replied the Army captain, with a shrug of his shoulders. "That and some of the other wild doings of to-night. Captain Boggs, you will prepare to accompany us back to camp."

"Why?"

"Because you're a prisoner, charged with conspiring to break the laws of the United States."

"But who'll look after my boat?" demanded Boggs.

"She'll be under guard of a squad of my men, and your mate, deckhands and engine-room force will be enough to give the boat any care she really needs. Mr. Overton, march the Mexicans out of the cabin under guard."

Hal promptly obeyed. Guarez and his companions appeared to be furious, and contended loudly that their rights were being infringed.

"That's all a matter for higher government authorities to settle,"

responded Captain Foster, with a shrug of his shoulders. "I cautioned you this morning, Guarez, against any enterprise of this sort, and you did not see fit to give my suggestion any consideration. You must now take the consequences. Sergeant Raney, take six men and escort the prisoners to camp. My compliments to Lieutenant Terry, and he is directed to take all precautions that the prisoners do not escape."

"Very good, sir."

After the escort had left with the prisoners Hal saluted his superior officer, asking:

"Sir, shall I re-post the sentries who were noosed and taken away from their posts?"

"It is hardly necessary, Mr. Overton. This boat is a government prize, and I propose to use her, for to-night at least, for the patroling of the river at this point. Mate, I see that you have a search-light."

"Yes, sir," the mate admitted.

"Is it ready for operation?"

"There is plenty of current, sir, and the lamp can be switched on from the wheel-house."

"Turn the light on once for a test, then."

The mate complied, sending a glare of light out over the dark waters.

"Switch the light off," called Captain Foster, next turning to remark to his young lieutenant:

"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.