ten men from F company marched on
to the pier, followed by Corporal Shimple of H company and four men. In
the wake of the two detachments walked Lieutenant Noll, who was soon
shaking hands heartily with three of his brother officers of the United
Services.

"May I ask what you see coming, gentlemen?" inquired Captain Foster,
suddenly, pointing down the river.

"It looks like some pirate craft, sir," replied Hal, after peering hard
through the darkness. "At least, that seems like a fair guess, for she's
moving along without lights."

"She's engaged in United States service of a somewhat stealthy nature,"
replied Captain Foster. "That's why the craft shows no lights. Mr.
Overton, how do you like the idea that you're to command a gasoline boat
yourself to-night, and one that is reputed to be exceedingly fast?"

Hal Overton felt a sudden glow of exultation as the situation dawned on
his mind.

"I wired, last night, for a fast gasoline boat to be sent here to aid
us," continued Captain Foster. "This coming craft is the answer to my
prayer, and the nearest collector of customs informs me that she's the
swiftest thing he could charter for the government in these waters."

"Then, sir, if the Mexicans try to put their motor boat across the river
to-night there'll be some real doings!" promised Lieutenant Overton.

"Real doings," indeed! The border excitement was about to break loose in
deadly earnest, but that was more than any of them knew at that time.

CHAPTER XVIII

AN ACT OF PIRACY

Moving slowly, with the graceful ease of a monster swan, the motor boat,
a craft under sixty feet in length, moved into the pier to shoreward of
the tug.

"Motor boat 'Restless'?" hailed Captain Foster.

"Yes, sir," came quietly from the youthful-looking sailor at the wheel.
Just then he quitted his post.

"Captain Halstead?"

"Yes, sir; here, at your orders."

Skipper Tom Halstead made the best military salute that he knew how,
while the handy boy of all things aboard the boat, Hank Butts, made the
bow-hawser fast and hurried along the pier to secure the stern hawser.

"A party of five United States officers coming aboard, Captain
Halstead," continued Captain Foster.

"All right, sir; we'll be mighty glad to have you aboard," Skipper Tom
answered quietly, but with a manliness and heartiness that made all of
the officers instantly take a liking to him.

Captain Foster introduced himself, and then his brother offic