gain," Dave answered.

The Navy launch was dashing full speed ahead. But with no clue to
follow, Darrin passed some anxious seconds. Should he follow on the
course he had been taking, or should he shut off speed? In the dark
there was a good chance that the submarine commander, if so minded,
would be able to double and head back for shore.

Land lights were still visible from his position. Dave turned to
estimate their distance.

"About six knots off shore," he concluded, half aloud.

"Sir?" questioned the corporal of marines, thinking the ensign was
addressing him.

"I was just telling myself that we're about six knots off shore."

"Yes, sir," replied the corporal, saluting.

"Listen to me, you men who are near enough to hear. Your understanding
of what is in my mind may help you the better to work with me on this
job. Two launches are keeping with us, over the starboard, and I judge
the nearer one to be about four knots off. Coxswain, use the lantern
signal and ask who commands."

Soon Hardy discovered that, in order to make his signal visible at
that distance, he would have to stand higher. Springing to the forward
deck his signal was instantly understood on the other craft.

Dave, who had jumped up beside him, read the answer:

"Ensign Dalzell."

"I was sure of it," Dave smiled. "Coxswain, order number 2 launch to
come up on parallel course, standing off half-mile to starboard of
us."

"Order understood," was flashed back from Dalzell's launch.

Bit by bit Dan overhauled, at last taking the position indicated.
Darrin's launch was moving at slow speed now, for he did not care to
run out of sight of land, thus leaving the way clear for the submarine
to double on him and put back toward Grand Harbor.

"Why doesn't the fellow take a chance on torpedoing us?" was signaled
from Dalzell's launch.

"He has only three," was Darrin's reply.

That was brief, but Danny Grin understood, as Dave had intended he
should, that the submarine was believed to be equipped with only three
torpedoes. Evidently the enemy still hoped for a chance to sink a
British battleship.

Suddenly he discovered that for which he sought, and in the same
instant a seaman called, as the rays of the searchlight shifted:

"Periscope two points off the port bow, sir."

"Right!" clicked Ensign Darrin.

"May I fire, sir?" begged Runkle, bending over his piece.

"Yes, try it. Pretty long shot, though."

Before Runkle could aim and d