“Oh, of course nothing is really going to happen,” laughed Hal.  “It is just the feeling that is over me.  That’s all.”

It was fully three o’clock by the time Lieutenant Danvers decided they were far enough out to sea, and far enough from any craft in those waters.  Not a stick or a stack of another vessel showed within ten miles of them.  The scow was accordingly cast loose and allowed to drift.

Captain Jack was at the tower wheel again, as Eph and the two sailors returned from setting the scow loose.

“We’ve got to be sure to record one good hit against that old barge of stone,” muttered Lieutenant Danvers, who stood beside the youthful submarine commander.  “The sea is roughening, and I doubt if we could pick up that scow in tow again.  We’ve got to destroy her, or she’d be a fearful menace to navigation, drifting about in the night in the path of incoming vessels.”

“Oh, I guess you’ll get rid of her easily enough,” spoke Jack, confidently.  “You’re a professional at this business, sir.”

“So are the two men with me,” nodded the officer.  “By the way, Ewald can just as well come on deck and take the wheel, if you want him to do so.  Then you can go below and see all that we do with a torpedo.”

“Now, that’s what I call a great idea,” cried Benson, enthusiastically.  “I want to know just how a torpedo is handled at the time of firing.”

“It’s the only thing you have left to learn about this business,” smiled the naval officer.  Then he passed the word for Ewald.  When that it sailor had taken the wheel, the naval officer and the young submarine skipper went below.

“We’ll swing in one of the dummy torpedoes, first, of course,” announced Mr. Danvers.

One of the dummies was, therefore, hauled forward on a truck, then forced on into the torpedo tube.  Jack watched, intently, this part of the business.

The torpedo itself was a cigar-shaped affair, with a propeller at the after end.  This propeller was set in motion by means of an engine in the after part of the torpedo, the engine being so constructed that it was set in operation at the moment the torpedo left the tube and entered the ocean outside.  The propeller was fitted with apparatus that would drive the torpedo in a straight line.

“The torpedo looks like a miniature submarine, doesn’t it?” muttered young Benson.

“It surely does,” nodded the naval officer.  “And, since the torpedo has to travel under water, what better model could have been chosen?  Now, the engines in these dummy torpedoes can be set for two, four, six or eight hundred yards, and the torpedo, once it enters the water, travels forward, in a straight line until the engine gives out.  That is, the torpedo travels ahead if it doesn’t hit something.  So, in actual war conditions, we would always get nearer to the object than the distance for which the engine is set to run.  The speed of a torpedo like this, under water, is a good deal better than thirty miles an hour, but the distance the torpedo can go is naturally short.  That is a direct consequence of its speed.  Now, Mr. Benson, would you like to know how to fire the torpedo, since it is already in the tube?”