On the double quick came the sh.o.r.e duty party. Dave Darrin found himself surrounded by blue jackets.

"This lady is very nervous, and with good reason," Dave explained to the boatswain's mate. "She just had a handbag of money s.n.a.t.c.hed from her by a thief. The bag has been returned, and now she wishes our escort to the dock, that she may not be attacked again. She is on her way to board a ship that will take her back to the United States. Boatswain's mate, I wish you would ride in the carriage at her side, while the rest of us walk on the sidewalk close to the carriage."

"Aye, aye, sir!" responded the mate, saluting, then turning and lifting his cap gracefully to the woman. He helped her into the carriage, then took his seat beside her.

Dave and the nine seamen remained on the sidewalk, but kept close to the carriage as the horses moved along at a walk. Darrin had no further fear that another attempt would be made to seize the money by force. Eleven men from the American Navy are guard enough to keep even a crowd of rascals in order.

"Since Cosetta was looking on from the doorway, that must have been one of his jobs, engineered by him, and carried out by his own men," Dave told himself, swiftly. "Most of the men in the crowd must have been his own men, too, posted to take the money again, under pretense that a fight with sailors had started.

So I've been the means of blocking another profitable enterprise for that fellow, Cosetta. By and by the scoundrel will feel a deep liking for me!"

The first thief, he whose wrist Seaman Rogers had broken, had promptly vanished. Unmolested, the blue-jackets escorted the carriage out on to a dock next to the one at which the launch from the "_Long Island_" lay.

Dave himself a.s.sisted the woman to alight from her carriage on the dock, at the end of which lay an American steamship.

After she had thanked the young officer earnestly, Darrin, cap in hand, remarked:

"I am afraid I shall have to trouble you, madam, for your name.

I shall have to turn in a report on this occurrence on my return to my ship."

"I am Mrs. Alice Black," replied the woman. "My home is in Elberon, Ohio, and I shall probably go there soon after I reach New York.

This steamship does not sail immediately, but my money will be safe on board with the purser."

Darrin gave his own name.

"You have done me the greatest service possible, Mr. Darrin, for you have saved me from utter poverty."

"Then I am very glad indeed," Dave a.s.sured her, and promptly took his leave.

Before going off the dock Darrin secured the name of the boatswain's mate, also, for inclusion in his report.

Then, with Rogers, he returned to the launch and was speedily back on his own ship.

The packet of papers entrusted to him by the consul were at once handed over to Captain Gales.

The launch was left fast to a swinging boom, and soon after was employed to take ash.o.r.e Lieutenant Cantor, who had received sh.o.r.e leave for a few hours.

For the first time in several days, Dave and Dan had time to chat together that afternoon. That was after Darrin had turned in a brief report on the a.s.sistance rendered an American woman ash.o.r.e.

"Cantor seems to have let up on you, apart from being as grouchy as he knows how to be," Danny Grin observed.

"That is because there is nothing he can really do to me," Dave answered, with a smile.

"Just the same," urged Dan, "I would advise you at all times to keep your weather eye turned toward that chap."

"He really isn't worth the trouble," Dave yawned, behind his hand.

"And, fortunately, I shall not always be compelled to serve under him. Officers are frequently transferred, you know."

"If Cantor found the chance, you might last only long enough to be transferred back to civil life," Dan warned him. "Dave, I wish you would really be more on your guard against the only enemy, so far as I know, that you have."

"I'm not interested in Cantor," retorted Dave. "It would do me a heap more good to know what reply General Huerta will finally make to the American demand for satisfaction over the Tampico incident."

"Huerta won't give in," Dan predicted. "If he did, he would he killed by his own Mexican rabble."

"If Huerta resists, then he'll have to fight," Dave exclaimed, warmly.

"And if he fights most of the Mexicans will probably stand by him," Dalzell contended. His only hope of saving his own skin lies in provoking Uncle Sam into sending a spanking expedition.

At the worst, Huerta, if badly beaten by our troops, can surrender to our commander, and then he'll have a chance to get out of Mexico alive. If Huerta gave in to us, he would have all the Mexican people against him, and he'd only fall into the hands of the rebels, who would take huge delight in killing him offhand. It's a queer condition, isn't it, when Huerta's only hope of coming out alive hangs on his making war against a power like the United States."

"Open for callers?" inquired Lieutenant Trent's voice, outside Dan's door.

"Come in, by all means," called Ensign Dalzell.

Lieutenant Trent entered, looking as though he were well satisfied with himself on this warm April day in the tropics.

"You look unusually jovial," Dan remarked.

"And why shouldn't I?" Trent asked. "For years the Navy has been working out every imaginable problem of attack and defense. Now, we shall have a chance to apply some of our knowledge."

"In fighting the Mexican Navy?" laughed Dave.

"Hardly that," grinned the older officer. "But at least we shall have landing-party practice, and in the face of real bullets."

"If Huerta doesn't back down," Dave suggested.

"He won't," Danny Grin insisted. "He can't---doesn't dare."

"Do you realize what two of our greatest problems are to-day?"

asked Lieutenant Trent.

"Attack on battleships by submarines and airships?" Dave inquired, quietly.

"Yes," Trent nodded.

"Huerta hasn't any submarines," Dan offered.

"We haven't heard of any," Trent replied, "Yet how can we be sure that he hasn't any submarine craft?"

"He has an airship or two, though, I believe," Dave went on.

"He is believed to have two in the hands of the Mexican Federal Army," Lieutenant Trent continued. "I have just heard that, if we send a landing party ash.o.r.e on a hostile errand, on each warship an officer and a squad of men will be stationed by a searchlight all through the dark hours. That searchlight will keep the skies lighted in the effort to discover an airship."

"And we ought to be able to bring it down with a six-pounder sh.e.l.l,"

Danny Grin declared, promptly.

"There is a limit to the range of a six-pounder, or any other gun, especially when firing at high elevation," Trent retorted.

"An airship can reach a height above the range of any gun that can be trained on the sky. For instance, we can't fire a sh.e.l.l that will go three miles up into the air, yet that is a very ordinary height at which to run a biplane. Have you heard that, a year or more ago, an English aviator flew over warships at a height greater than the gunners below could possibly have reached? And did you know that the aviator succeeded in dropping oranges down the funnels of English warships? Suppose those oranges had been bombs?"

"The warship would have been sunk," Darrin answered.