"Going ashore with us to-night!" asked Hal, one evening, after the meal
had been disposed of and the dishes washed and put away.

"Not to-night," replied Jack Benson, with a shake of his head. "I'm
too much in earnest about wanting to know all about the handling of a
submarine to waste all my leisure in fooling. See this book on
mechanics? I'm going to stay aboard and study it to-night, and see
how much of it I can get into my head."

"Good luck to you," laughed Eph. "If you succeed, maybe we'll stay on
board to-morrow night and let you be schoolmaster. But this was
pay-day, and the ice-cream soda up in the village fizzes good to me."

As soon as they had gone, Jack placed his book on the cabin table and
drew up to it. Until dark he plodded through the pages, then turned on
the electric light. Finding the book more difficult of comprehension
than he had expected, he crouched over the volume, devoting his whole
attention to the first few pages. Nine o'clock came and went.
Half-past nine went by. Had Benson heeded the time he would have
concluded that his comrades had found village life unusually alluring
to-night.

Through the dark, quiet boat yard prowled a man, pausing and listening
every few steps, as though bent on trying to keep out of the sight of
the night watchman.

It was Jack's old enemy, Josh Owen, who, so far, had cleverly kept out
of the way of the officers seeking him.

In some way Josh had learned that the other two submarine boys were up
in the village. The lights shining from the interior of the submarine
proved that someone was aboard. Hence it must be Jack Benson.

Down at the water's edge lay the "Pollard's" rowboat tender. A final
survey satisfied Josh Owen that the watchman was nowhere about. An
instant later the former foreman was in the rowboat, handling the oars
so quietly as to make hardly any sound. Two or three minutes later he
was alongside the "Pollard," stealthily making the painter fast to the
deck rail. Then, in his bare feet, Josh went softly up over the side.
At the manhole he crouched to peer below. He could not see the boy,
but the shadow told him that Benson was sitting with his back to the
stairway.

A gleam of insane wickedness in his eyes--for brooding had somewhat
unbalanced the former foreman's mind--Josh Owen started softly down
the stairway.

Fancying he heard some slight, unusual sound, Jack Benson turned. Too
late! The powerful ex-foreman leaped,