k his fist at
Mr. Henderson.

"I might ask what right your ship has to get in my path," replied the
inventor. "It was all an accident."

"Mighty queer," muttered the naval commander. "Looks very suspicious.
How do I know but what you're a torpedo from some foreign nation?"

"Because this is not a torpedo," replied Mr. Henderson. "It is a new
submarine boat of my invention, and I was giving it a trial spin."

"I guess you'd better come aboard and do your explaining," went on the
captain. "I don't like the looks of things. Lower a boat!" he shouted,
"and bring those chaps to my cabin. I want to question them."

It did not suit Professor Henderson to have his plans upset in this
fashion. Nor did he care to give a detailed description of his ship to
officers of the war department. He had many valuable inventions that
were not patented. So he determined to outwit the pompous commander of
the cruiser.

The noise made in preparing the small boat for lowering over the side of
the big ship could be plainly heard.

"Go below, all of you, and as quietly as you can," whispered Mr.
Henderson.

Andy, Mark and Jack obeyed. At that instant the side of the warship was
almost deserted, for the sailors who had gathered to observe the
_Porpoise_ had gone to lower the small boat.

No sooner had Jack, who was in the rear, disappeared through the manhole
than the professor, with a quick jump, followed him.

"Here! Come back!" shouted the warship's captain as he saw Mr.
Henderson's head disappearing from view. "Come back I say!"

But with a quick movement the inventor pulled down the manhole cover and
clamped it. Then he sprang to the conning tower, and, with a jerk,
opened the levers that admitted water to the tanks. The _Porpoise_ began
to sink slowly, and then more suddenly, so that, in less than a minute,
she was out of sight beneath the waves, and the angry, gold-laced
captain was staring in wonderment at the place where the submarine had
been. The spot was marked only by a few bubbles and some foam.

"I guess he'll wait some time for an explanation," spoke Mr. Henderson,
as he started the big screw and sent the _Porpoise_ ahead at a swift
pace.

"That was rather a narrow escape," observed Jack, standing at the foot
of the conning tower stairs and talking to Andy and Mr. Henderson, who
was steering.

"It certainly was," agreed the professor. "I have not yet become used to
seeing things very far ahead in the dimness cause