"This man says, sir," continued the petty officer, "that he saw your friends, sir, going aboard a white knockabout sloop."

"He did, eh?" demanded the astonished Eph. "How long ago was that?"

"Only a few minutes ago, sir," replied the sailor.

"You're sure you saw Mr. Benson and Mr. Hastings?"

"Yes, sir."

"That's queer," reflected Eph. "It wouldn't be like them to go sailing at this time of the night, and without notifying me, either. But, then, I didn't see anything of 'em aboard that sloop, either."

Eph was silent for a few moments, thinking. Then, suddenly, he leaped up in the air, coming down flat-footed.

"Crackey!" e.j.a.c.u.l.a.t.ed Eph Somers.

For a moment or two his face was a study in bewilderment.

"Mighty strange things have been happening all through this cruise," Eph muttered, half-aloud. "Especially happening to Jack! Now, the two of them go aboard that sloop, and immediately after the boat puts out to sea in the dead of night. What if Jack and Hal have been shanghaied on that infernal sloop?"

Cold chills began to chase each other up and down the spine of Eph Somers.

He was not, ordinarily, an imaginative youth, but just now the gruesome thought that had entered his mind persisted there.

He began to pace the platform deck in deep agitation.

"Anything wrong, sir?" questioned the marine sentry, halting and throwing his rifle over to port arms.

"That's just what I'd give a million dollars and ten cents to know!"

exploded Eph.

"Gunboat, ahoy!" he shouted, some twenty seconds later.

"'Farnum,' ahoy!"

"I half believe, sir," Eph rattled on, "that my two comrades, Mr. Benson and Mr. Hastings have been tricked, in some way, and carried out to sea on that knockabout. They'd have been back from sh.o.r.e by this time, if nothing had happened."

"What do you want to do, Mr. Somers?"

"Want to do, sir?" retorted Eph. "I know what I'm going to do. I'm going to slip moorings and chase after that knockabout. What I wish to know from you, sir, is whether you'll send another marine or two on board, so that I can back up my demand to find my friends?"

"I'll have to ask the lieutenant commander about that, Mr. Somers."

"Can you do it, now, sir?" asked Eph, energetically.

"Instantly. I'll let you know the decision as soon as it's made."

Eph, hanging at the rail in the silence that followed, had no notion of whether his request had been a correct one. All he knew was that his suspicions had surged to the surface, and were threatening to boil over.

It was a huge relief to the boy when Mr. Mayhew's voice sounded from the rail of the gunboat. Somers swiftly answered all questions.

"Your craft and crew are in a measure under our protection and orders,"

decided Mr. Mayhew. "I think we may properly extend you some help. I will send some men to you, and a cadet midshipman who will have my instructions."

"Will you send them quickly, sir?" begged Eph.

"I'll have men on board of you by the time that your engines are running,"

promised the lieutenant commander.

"Engines?" That word came as a fortunate reminder to the submarine boy. He darted below, almost yanking Williamson from his berth, nearly pulling the machinist into his clothes. By the time that Williamson was really wide awake he found himself standing by the motors forward.

Then young Somers darted onto deck again, just in time to see the boat coming alongside. It brought two more marines, one of them a corporal.

There were also two sailors. A cadet midshipman commanded them.

"Mr. Somers," reported the cadet midshipman, "I am not intended to displace you from the command of this boat. I am here only with definite instructions in case you succeed in overhauling that white sloop."

"What-" began Eph. Then he paused, with a half-grin. "Really," he added, "I ought to know better than to quiz you about your instructions from your superior officer."

"Yes, sir," a.s.sented the midshipman, simply.

Eph turned on the current to the search-light, swinging the ray about the bay. Then, too impatient to sit in the conning tower, the submarine boy took his place by the deck wheel.

"Will your seamen cast loose from the moorings?" Somers asked.

"Yes, sir," replied the midshipman.

"If there's anything wrong, good luck to you," sounded the cool voice of Lieutenant Commander Mayhew, from the gunboat's rail.

"Thank you, sir."

No sooner had the moorings been cast loose from than Eph sounded the slow speed ahead bell. Within sixty seconds the propellers of the "Farnum" were doing a ten-knot stunt, which was soon increased to fourteen.

One of the seamen now stood by to swing the searchlight under Eph's orders.

By the time that the submarine reached the mouth of the bay the light faintly picked up a spread of white sail, off to the East.

"That's the knockabout," cried Eph, excitedly. "Now, see here, keep that ray right across the boat as soon as we get half a mile nearer."

"It'll show the boat that you're chasing 'em, sir," advised the midshipman.

"I know it," admitted Eph. "But it will also keep the rascals from dumping my friends overboard without our catching 'em at it."

"What do you think the men in charge of that boat are, sir-pirates?"

"They're mighty close to it, if they've shanghaied Mr. Benson and Mr.

Hastings and put to sea with 'em," rejoined Eph. Then he rang for more speed. Down below, Williamson almost instantly responded. The "Farnum" now fairly leaped through the water.

"Turn the light on the knockabout, now, and keep it there," directed the submarine boy.

There was a seven-knot breeze blowing. At the speed at which the submarine boat was traveling the distance was soon covered.

And now the searchlight revealed two men in the standing-room of the sloop, one of whom, a bearded man, was looking backward over his wake much of the time.