"It doesn't matter so much if these rascals get me, but I don't want them to work any mischief to the submarine."

"Bravo!" nodded David Pollard, looking on with a smile.

It is a fact that life in a constant atmosphere of danger renders the average man all but indifferent to fear. Those who meet perils daily grow to consider danger as all a part of the day's work. Perils which, a year before, would have kept Jack Benson awake with dread for a week now appeared to him as not worth thinking about until they happened.

Jack remained ash.o.r.e until half-past nine. He hoped to hear some word of what the Secret Service men might have learned, or of what these representatives of Uncle Sam were doing. But no word came, so the submarine boy went down to the beach. There was but one harbor boat in sight.

"Ah done thought yo'd be gwine back to do little ship, sah, so Ah done waited fo' you'," explained the negro in the boat. "Any mo'

ob yo' pahty to go abo'd to-night, sah?"

"No," Jack answered. "I'll be the last one to put off to-night."

Nor did he forget to reward the darkey's enterprise by handing him rather more than the usual boat hire.

As he stepped aboard Jack found Hal pacing the platform deck.

"Keeping deck watch, old fellow? I'm glad see that," Captain Jack said, commendingly.

"Yes; I'm on until midnight. Then Williamson stands watch until three-thirty in the morning. After that Eph comes up and takes the trick until it's time to call us all."

"When do I come on watch?" asked Jack.

"I never heard the captain of a craft had to stand watch in port,"

laughed Hal Hastings "Besides, old fellow, we couldn't be sure you'd be aboard to-night. So the watches are all arranged. Anyway, you'd better turn in and get a full night's sleep, for you've more on your mind than the rest of us."

"Then tell Williamson, and have him pa.s.s the word on to Eph, that watch ought to be very strictly kept," answered the young captain.

A few minutes Benson remained on deck, chatting with his chum. When he at last went below the submarine captain lost little time getting into his berth.

When Machinist Williamson came on deck at midnight a light wind was blowing, but the air was not really chilly. In his heavy reefer the machinist felt wholly comfortable after he had lighted his pipe and started his slow walk back and forth along the deck.

There did not appear to be overmuch sense in keeping this deck watch.

Only a short distance away lay the United States gunboat "Waverly,"

with her alert marine guard. Though there was no moon, the starlight was bright enough to enable a marine on the gunboat to see anything that might skim over the water toward the "Benson."

Yet Williamson was on watch, under instructions, and he was a faithful fellow who meant to do his full duty.

"Seems kinder tough, of course, to be so long out of one's bunk in the middle of the night," the machinist admitted to himself.

Yet, had his vision been keen enough to know what was happening on sh.o.r.e, almost directly opposite the "Benson," Williamson would have been tenfold more alert.

Over there on the sh.o.r.e, in a clump of flowering, semi-tropical bushes, crouched two men. On the ground with them lay a metal cylinder some two feet long and seven inches in diameter. There was also a coil of wire and a boxed magneto battery.

One of the pair held to his eyes a pair of night marine gla.s.ses.

Incessantly this watcher kept his gaze focused on Williamson.

About two o'clock in the morning Williamson found it necessary to go below for a few moments. After reaching the conning tower he paused, for a few moments, to look keenly all about him.

Yet, look as he would through the night, the machinist's vision could not see that the bush hidden pair on sh.o.r.e, guessing his intention from his stop by the conning tower, had silently taken to the water.

With them they towed the metal cylinder, which floated. To the cylinder was attached one end of the light wire.

Some distance out from the sh.o.r.e the pair halted, treading water, only their eyes above the surface. But Williamson could not make out such small objects at the distance. Then he went below.

"Now, for it," breathed one of the swimming pair, tensely.

Both swimmers struck out strongly, yet silently, making fast progress through the water by means of some of the best strokes known to swimmers.

When they reached the port side of the submarine Williamson was still below. Nor had the attention of the marine guard on the "Waverly"

been attracted.

In just another swift instant the swimmers made a dive that carried them and their cylinder below the surface.

Straight up against the bottom of the hull the pair went.

When they returned to the surface the metal cylinder was in place below.

Glancing backward only once, to make sure that Williamson was not yet on deck, and that the gunboat's marine guard had not detected their stealthy work, the swimming pair struck out l.u.s.tily for sh.o.r.e.

Back into the same clump of bushes they made their way. In the first few moments neither of the recent swimmers appeared to dare a glance into the face of his comrade. In silence they fitted the sh.o.r.e end of the wire to the battery.

Then one of the pair seized the handle to pomp the fatal electric spark along the wire to the hidden mine under the "Benson's" hull.

"Remember what happened to the 'Maine'!" this wretch chuckled hideously.

CHAPTER XIX

A JOKE ON THE SECRET SERVICE!

"What's that noise?" wondered Williamson.

He stopped, listening intently, for he was still below.

Against the bottom of the "Benson's" hull he heard a steady, slow, monotonous b.u.mping. As he listened, his face took on an anxious look.

"We're in a friendly port," muttered the machinist. "It can't be anything very wrong, and yet--"

That slow steady b.u.mping continued.

"Anything b.u.mping against the bull of a boat at anchor, in that fashion may be wrong," concluded the man, swiftly.

His mind made up to this much, the rest was not difficult to decide. The cause of that b.u.mping required instant investigation. Williamson caught up the tool that came quickest to hand, a pair of nippers, thrust them into his jumper and raced up to the deck.

"If it's any real mischief," he muttered, "I hope I won't be too slow--too late!"