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, “when—­”

Just then he stopped, though he did not appear startled.

Straight up out of the watery depths shot a Carroty-topped boy, his wet skin glistening in the sun.

“Good gracious!” gasped the girl.  “Where did that boy come from?”

“Say, sir,” called up Eph Somers, distinguishing the lieutenant in his swift look, “where do you want the submarine boat to anchor?”

“What’s that to you, young man?” called down Mr. Featherstone, bluntly.