scow, before dark," muttered Lieutenant
Danvers.

"Are you going to let me fire the torpedo at her, sir?" demanded Skipper
Jack Benson, eagerly.

"If you feel sure you can do it," replied the naval officer. "For that
matter, if you fail, there'll be one loaded torpedo left, and I can
take the second shot."

At a sign from the young skipper Eph hurried below, to relieve Hal
Hastings, who wished to see some of the fun. Hal came up into the
conning tower to take the wheel while Jack Benson slipped below to
direct the loading of the torpedo into the tube. Then Biffens, the
sailor, took his post by the firing lever, while Ewald stood back to
pass the word from the conning tower.

This loaded torpedo, like the dummies, had been set to run four hundred
yards. Captain Jack, therefore, determined to release the torpedo at
a range of three hundred yards.

The "Hastings" had drifted somewhat away from the scow, but Jack, one
hand on steering wheel and the other at the signals, ran the submarine
over so that he could head the craft around to deliver a broadside fire
at the scow, at right angles. When he had the "Hastings" in this
position he shouted down:

"Be ready, Ewald!"

"Aye, aye, sir!"

A breathless instant followed, during which the young submarine commander
took his last sight from the conning tower.

"Fire!"

"Fire it is, sir."

Jack and Hal could just barely see, from the tower, the slight commotion
that the torpedo made in the water at the bow when released.

Hal, watch in hand was counting: "One, two, three, four--" and so on.

Suddenly there came a low rumble, followed by--

Boo-oom!

The explosion was a dull and sullen one, but loud enough to make the
blood of the submarine boys tingle. A column of spray shot up, followed
by detached whiffs of smoke, for the torpedo had exploded beneath the
surface.

In the same instant a sound of rending timbers reached their ears. Then
the scow--where was it? Only the waters rolled where the scow had
been. Captain Jack and Hal rubbed their eyes.

"The same thing would have happened to a battleship," smiled Lieutenant
Danvers, who had come up behind them. "Now, you young men begin to have
something like an idea of what an engine of war you are handling,
because this craft would be much more deadly, and vastly more
nerve-racking to an enemy, because she would approach under water, and
those on the battleship would have little or no means of gauging