moment the tower manhole was opened, and Jack Benson, with a wave
of the hand, stepped out, his bathing suit changed for his uniform. He
lifted his cap in a joyous salute to those on shore.

"By Jove, Jack, but you're a wonder!" shouted Mr. Farnum across the water.
"I'll have Dave Pollard excited when I write him about this thing. But
you have me guessing how the trick was done."

Once more Benson signaled the small boat in close, after the anchor had
been lifted. Now, the young submarine captain came in to shore.

"You come on board with me, Mr. Farnum?" invited Jack.

"Are you going to show him how you worked the trick?" demanded Mr.
Melville, quickly.

"Yes, sir."

"Then I believe we'll all come on board."

"I--I am sorry, sir." Jack hesitated. "If anyone but Mr. Farnum comes
aboard I shall show nothing. Later on, when Mr. Farnum and I have talked
this matter over--"

"Are you going to stand for this boy's nonsense, Farnum?" broke in the
capitalist, angrily.

"I guess I shall have to," responded the builder, with the pronounced
drawl which, with him, was a sign that he was close to inward anger.
"Mr. Melville, I must beg you to remember that the secret, whatever it
is, belongs, so far, to Captain Benson. You may not approve, but I
think he is wholly right in this instance."

The capitalist bowed stiffly. He and his son remained on the shore as
Farnum embarked with his young employe. They were soon on board the
"Pollard," which was not long in sinking. Then, after a few minutes,
Jack's head once more shot above the water. The shore boat was waiting,
and again dropped the anchor close to where the boy had come up. Jack
stood in the boat for a few minutes, taking in deep breaths and sunning
his wet skin. Then, for the second time, he dived below the surface.

Five minutes afterward the "Pollard" was at the surface and moving back
to her moorings. Mr. Farnum and Captain Jack returned to the shore.
The boatbuilder's face was glowing with delight.

"You saw our young captain come up while I was with the 'Pollard' down
on the bottom, didn't you?" inquired the yard's owner.

"Yes," admitted Mr. Melville, grudgingly, while Don half scowled, then
turned his head away. "But how is the thing done?"

"That," replied Jacob Farnum, courteously, "at the request of Captain
John Benson, must remain a secret for the present."

"Oh!" said the capitalist, but his tone was ominous.

CHAPTER III

M