about this?"

"I don't have to ask them," nodded Captain Jack, confidently.

"Why not?"

"We settled it all, days ago, sir."

"And they both agreed with you?"

"Down to the last jot, Mr. Farnum. They saw the beauty and the boldness of the plan."

Oh, well, go ahead, then, responded Mr. Farnum, rising and standing by the cabin table. "Of course, the picturesque and romantic possibilities of the scheme are plain enough to me. We'll have the people at Spruce Beach agape with curiosity, then wild with enthusiasm. And, really, to be sure, we have to arouse the enthusiasm of the American people over this whole game. That's the surest way of forcing Congress to spend more money on our boats."

"Where are you going, Jake?" called the inventor, as his partner started aft.

"To the stateroom, to get a little nap," replied the shipbuilder. "We're not by any means due at Spruce Beach yet."

"Jake Farnum is surely not a coward," chuckled Mr. Pollard, as the stateroom door closed. "Nor is he over anxious about any detail in our little game, or he couldn't go to sleep at this important time. I know I couldn't get a wink of sleep if I turned in now. I've simply got to sit up, wide awake, until I see the finish of your bold stroke, Jack Benson."

Captain Jack laughed easily, then glanced at his watch to note the lapse of time since he had made his last calculation of their whereabouts. It is one thing to be in the open air, navigating a vessel, but it is quite another affair to be fifty-odd feet below the surface, calculating all by the distance covered and the course steered.

"Any deviation in the course, Eph?" Captain Jack called up into the conning tower.

"Not by as much as a hair's breadth," retorted young Somers, almost gruffly, for with him, to depart from a given course, was well nigh equal to a capital crime.

Jack touched a button in the side of the table. Obeying the summons, quiet Hal Hastings thrust his head out into the cabin.

"Just the same speed, Hal?" the young captain asked.

"Hasn't changed a single revolution per minute," Hastings answered, briefly.

With his watch on the table before him, and employing the scale rule and dividers, the young submarine skipper placed a new dot on the chart.

"Something ought to be happening in three quarters of an hour," Benson remarked, with a chuckle, to Mr. Pollard.

Less than half an hour later the young submarine skipper climbed up into the conning tower beside Eph.

"Same old straight course, eh, lad?" asked Jack quietly.

"You know it," retorted Eph.

"Then we're where we ought to be," responded Jack Benson, bending forward. With his right hand on the speed control he shut off speed.

"Now, just sit where you are, Eph, until I come up again," advised the young commander.

"Going to the surface?" demanded Somers, with interest.

"Pretty close," nodded Benson.

Calling Mr. Pollard to his aid, Jack began to operate the machinery that admitted compressed air to the water tanks, expelling the water gradually from those same tanks. This was the means by which the submarine boat rose to the surface. All the time that he was doing this, Jack Benson kept his keen glance on the submersion gauge. At last he stopped.

"How is it up there, Eph?" he called, pleasantly.

"Why, of course there's a lot of good daylight filtering down through the water now," Somers admitted.

Captain Jack went nimbly up the spiral stairway. Now, he had still another piece of apparatus to call into play. This affair is known to naval men as the periscope.

In effect, the periscope is a device which in the main is like a pipe; it can be pushed up through the top of the conning tower, through a special, water-proof cylinder, until the top of the periscope is a foot, or less, above the surface of the water.

The top of this instrument is fitted with lenses and mirrors. Down through the shaft of the periscope are other mirrors, which pass along any image reflected on the uppermost mirror of all. At the bottom of the periscope is the last mirror of the series, and, opening in upon this, there is an eyepiece fitted with a lens.

As Captain Jack Benson applied his right eye to the eyepiece he was able to see anything above the surface of the water that lay in any direction that the periscope was pointing.

"Right opposite Spruce Beach, as the chart showed!" chuckled the young commander. Under the magnifying effect of the eyepiece lens Benson could see the beach, the flag-bedecked hotels, and the moving masses of people on the shore. Yet, all this time, he was out at sea, more than a mile from the beach. The periscope itself, if seen from a boat an eighth of a mile away, would undoubtedly have been taken for a floating bottle.

"Let me have a peep," demanded Somers.

Eph looked briefly, then chuckled:

"Must be thousands of people over yonder, wondering what on earth has happened to us!"

"Do you make out the gunboat, at anchor to the north of the hotel section?" inquired Captain Jack.

"Oh, yes. Say, they'll have an awakening on that gray craft, won't they?"

"If we don't make any slip in our calculations," answered Benson, gravely.

"Well, we're not going to make any slip," asserted Eph Somers, stoutly.

"Now, keep quiet, please, old fellow. I want to do a little calculating before we take the last, desperate step."

All this time the conning tower of the submarine was just a bit below the surface. Nothing but the slender shaft and the small head of the periscope was above the wash of the lazy waves.

Captain Jack soon had his calculation made. Then, with a quiet smile, he remarked:

"I guess you'd better get below, Eph, for your part. I'll take the wheel, now, and Mr. Pollard will attend to the submerging mechanisms."

Eph laughed joyously as he darted below. He had a part assigned to him that was bound to be enjoyable.

"Mr. Pollard!" called down the young skipper, a few moments later.

"Aye, Captain Jack!"

"Let her down slowly, please, until the gauge shows just fourteen feet. That's the greatest depth I dare try for the course we're going to follow."

"Aye, Captain Jack. Fourteen feet it shall be."

For the benefit of some readers who may not understand, it is to be stated that the charts of harbors bear markings that show the exact depth of water at every point in the harbor at low tide. Thus, the chart of the harbor just north of Spruce Beach had already told the young submarine skipper just how far below the surface he could travel with safety to his craft.

Further, he knew the draft of the "Waverly" to be eleven feet. So the youthful commander could feel quite certain that he would be in no danger of colliding, below the water-line, with Uncle Sam's gunboat.

On the deck of the "Waverly" itself there was the same spirit of expectancy that there had been an hour earlier in the afternoon.

Lieutenant Featherstone, executive officer of the gunboat, was not, however, impatient. In fact, he stood at the rail, aft, a pretty girl beside him, and both were looking down musingly at the rippling water below.

"As I was saying," drawled the lieutenant,