Jack Benson, standing stealthily, got a good look, for the first time, at the top of that drawing board.

“A chart of the bay, of course,” muttered Benson, savagely, between his teeth.  “The fellow is marking down the exact position of that mine!”

Still, the submarine boy did nothing to betray his own presence.  He watched and wondered.  The thought struck him that this long-legged one might be an officer of the Army, on observation duty like the submarine boy himself.

“But that isn’t right; I’m sure it isn’t,” decided young Benson, quickly.  “If they fellow were here on honest business, he wouldn’t have sneaked out here to get in position.  Besides, I have a vague remembrance of this fellow, and I don’t connect him with anything honest!”

The Army tug, out on the bay, was now engaged in planting a second mine.  Again the slim stranger was all attention.  When the crane began to lower the mine, a second mark was made on the chart on the drawing board.

Now, once more, the fellow lay at full length, watching intently off over the bay.  At his right hand lay drawing-board, the book and the field-glasses.

“I’ll give him a little excitement!” grimaced Jack Benson, stealing softly forward.

Suddenly the boy swooped down upon drawing board, book and glasses, then, with a panting whoop, wheeled and started off on a dead run.

“Here you—­stop!” yelled the slim one, hoarse with sudden anger.

Like a flash the stranger was up and in pursuit.  As he quickened in the chase this stranger drew a revolver that glinted in the sun.

CHAPTER IV

JACK’S QUEER LOT OF LOOT

“Stop, thief!”

Jack Benson only sped onward the faster.

“Halt, you young rascal!” roared the long-legged one, in pursuit.

“The fellow who can call names like that, under the circumstances, has no sense of humor!” chuckled the submarine boy, inwardly.

“Drop that chart and book!” panted the one in chase.  “You’re stealing government property!”

“Yes, but which government?” Jack shot back at his pursuer.

“Are you going to stop?”

Jack’s answer was to increase his burst of speed slightly.

“Then I’m going to fire!” came the warning.  Glancing over his shoulder the submarine boy saw the long-legged one still running after him.  At the same time the pursuer was raising his revolver, sighting.

Jack felt a little shiver.  He had never been suspected of being a coward, yet he was willing to admit that he didn’t want to feel a chunk of lead plowing its way through him.

“Last word to halt!” yelled the pursuer, in an ugly tone.

“Fire, then!” dared Jack Benson.

Crack!  Whizz-zz!  Chug!  The weapon was discharged promptly.  Jack, still in flight, heard the bullet whistle by him.  Then it struck the sand, fifty feet ahead, throwing up a spurt of the fine particles.