, had caught the joy-infection of these orders to proceed
to Annapolis. To be sent to the United States Naval Academy on a tour
of instruction is what officers of the Navy often call "the prize
detail."

Farnum and his two youthful companions went, first of all, to the long,
shed-like building in which the third submarine craft to be turned out
at this yard was now being built. From inside came the noisy clang of
hammers against metal. The shipbuilder stepped inside alone, but soon
came out, nodding. The three now continued on their way down to the
little harbor. All of a sudden the three stopped short, almost with a
jerk, in the same second, as though pulled by a string.

At exactly the same instant Jacob Farnum, Captain Jack Benson and
Engineer Hal Hastings put up their hands to rub their eyes.

Their senses had told them truly, however. While the "Pollard" rode
serenely at her moorings, the "Farnum," the second boat to be launched,
was nowhere to be seen!

"What on earth has happened to the other submarine?" gasped the
shipbuilder, as soon as he could somewhat control his voice.

What, indeed?

There was not a sign of her. At least, she had not sunk at her moorings,
for the buoys floated in their respective places, with no manner of
tackle attached to them.

"A submarine boat can't slip its own cables and vanish without human
hands!" gasped the staggered Jack Benson.

"There's something uncanny about this," muttered Hal Hastings.

Jacob Farnum stood rooted to the spot, opening and closing his hands in
a way that testified plainly to the extent of his bewilderment.

CHAPTER II

HOW EPH FLIRTED WITH SCIENCE

Jack Benson was the first of the trio to move.

Without a word he broke into a run, heading for the narrow little shingle
of beach.

"Got an idea, Captain?" shouted Jacob Farnum, darting after his young
submarine skipper.

"Yes, sir!" floated back over Jack's shoulder.

"Then what's at the bottom--"

"Eph and the boat, both together, or I miss my guess," Captain Jack
shouted back as he halted at the water's edge, where a rowboat lay hauled
up on the shore.

Jacob Farnum's face showed suddenly pallid as he, also, reached the
beach. Hal, who was in the rear, did not seem so much startled.

"Do you think Eph has gone off on a cruise all alone?--that he has come
to any harm?" gasped the shipbuilder.

"I don't know, but I'm not going to worry a mite about Eph Somers until
I hav