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.

"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?" d