“Certainly, sir,” nodded Jack.  And then he continued as if reciting a lesson:  “Just give that firing lever at the back of the after port a quick shove to the right and downward.  That releases the charge of compressed air and forces the torpedo out.  At the same instant the forward port opens, so that the torpedo can be shot out into the water.  The compressed air also serves to keep the sea water from rushing in through the torpedo tube.  When the lever is swung up and back again that closes the forward port, and it is then safe to open this after port.”

“You’ve committed that to memory,” laughed the naval lieutenant.

“Oh, we’ve often talked this over, all three of us,” smiled Jack.

“Then, since you understand this part so well, Benson,” proposed Mr. Danvers, “perhaps you’d like to go forward, on deck, and see when this dummy torpedo is fired?”

“I surely would,” agreed the submarine boy “And Eph can just as well come with me.”

The two submarine boys, therefore, hastened above, out on the platform deck, and then further forward on the upper hull, until they lay out along the nose of the “Hastings.”

Danvers reached Ewald’s side in the tower, while Biffens waited below, at the lever, for the firing signal.

The “Hastings” was now drifting, rather aimlessly, something more than four hundred yards away from the scow.  As the sea was roughening all the while, the two submarine boys out forward were having a hard time of it.  Added to that, icy spray was falling over them.

Lieutenant Danvers quickly rang for speed and then brought the submarine boat within about three hundred yards of the scow, and at a position that pointed the nose of the “Hastings” at the middle of the scow’s hull, the line of fire making a right angle with the scow.

“Get ready to watch, out there!” warned the naval officer.

“Now, Eph,” glowed Jack, “we’re going to see the thing we’ve so often dreamed about!  We’ll see that dummy torpedo leap forth, like a real one.  For a little way, at least, we ought to see the track of the torpedo.”

“Feel like betting the dummy will bit the scow?” questioned young Somers, half doubtfully.

“Of course it will,” retorted Jack Benson, scornfully, “with naval experts on the job!”

Lieutenant Danvers gave the firing signal.

In the silence that followed, the two submarine boys hanging over the nose of the boat heard just a muffled click below.  Then—­

“There it goes!” shouted Jack Benson, with all the glee in the world.

Down beneath them, under the nose of the “Hastings” an object shot into brief view.  First the war-head, then the middle, then the tail and propeller of a fourteen-foot Whitehead torpedo swept away from them, two or three feet below the surface of the waves.  A line of bubbles came to the surface, showing that the torpedo was headed, straight and clean, for the stone-laden scow over on the ocean.  Then the torpedo, still under water, passed out of their range of view.