The lieutenant glanced at him admiringly.

"I believe you mean it," he said. "You are a brave lad. But come, we had all better turn in now."

"I guess you are right," said Frank; "and thanks for the trouble you have taken to explain all this to us."

"It was a pleasure, I am sure," was the lieutenant's reply, and they all made their way to the officer's cabin, where they prepared to retire for the night.

CHAPTER V

UNDER THE SEA

But there was to be no sleep for any aboard the German submarine X-9 that night. As the boys were just about to tumble into their bunks, there was the sound of a sudden commotion on the vessel.

Lieutenant Stein sprang to his feet, hastily donned what few clothes he had removed, and dashed from the cabin. With all possible haste, the boys followed suit.

Men were rushing to and fro and no one heeded the boys' presence, although they were rudely thrust aside by hurrying members of the crew several times.

"Wonder what's up?" said Jack.

"Don't know," replied Frank, "unless they have sighted one of our ships."

"By Jove! Let us hope not," breathed Jack.

But this was indeed the cause of the excitement aboard the submarine. A British battleship had been sighted in the distance, and Captain Von Cromp was preparing to attack the unsuspecting vessel, which had failed to sight her enemy, although the latter was fully exposed to view.

Frank and Jack approached the foot of the periscope, where they stood awaiting developments.

Outside a sudden storm swept the water of the North Sea in angry waves. The water lifted up the little vessel with the regular motion of a high-running sea. All was pitch dark.

The fact that men were hurrying about on deck, was only shown by the somber figures who now and then pa.s.sed in front of a single lantern. From out the engine room, already under water, arose the pound of heavy pounding and the weird crackling of the engines, as they were tried out.

Jack glanced at his watch. It was 10:30. Suddenly there came a shrill whistle from the little bridge of the submarine, standing high above the vessel, and covered with heavy canva.s.s. The officer in command, Captain Von Cromp himself, dressed hi heavy oilskins, raised a hand, the signal to go ahead.

A short, sharp signal to the engine room, a loud whirr of the motor, and the X-9 was speeding ahead. On both sides of the ship long waves formed, shimmering with light foam in the blackness of the sea. The X-9 moved westerly--toward the still unsuspecting battleship.

The heavens were covered with clouds. Not a star was visible.

It was impossible to see more than a few feet away from the strange craft. Captain Von Cromp, with his experienced eye, tried in vain to penetrate through this wall of solid blackness.

The wind kicked up the sea and the bridge was entirely flooded with water. There was hot a sound to be heard, save the heavy droning of the motor and the swish of the water pa.s.sing along the sides.

Suddenly, in the near distance, loomed up a great gray bulk, swinging high above the submarine upon the water. It was the British battleship.

And now submarine X-9 had been discovered. A heavy boom rang out, but the little craft was not damaged.

Another signal came to the ears of the two boys. Men rushed upon deck and soon the submarine was prepared for action. The flagpole was taken down. Part of the bridge was folded together and securely fastened. The periscope was fixed at its proper height. Then the entrance through the combined bridge and conning tower was hermetically sealed. A moment more and the tanks were opened, telling the lads that the submarine was about to submerge. The gasoline motors stopped their endless song.

From now on electricity would drive the vessel forward.

Near Frank and Jack, at the periscope, stood Lieutenant Stein, looking at the British ship. The sailors took their stations near the torpedoes. The interior of the boat was now lighted with two small electric bulbs. They made the darkness visible, but gave no light outside. Everywhere was the stale smell of oil. The boys found it impossible to speak to each other because of the noise of the engine and the water. The heat was oppressive.

From time to time the officer in command of the three torpedoes looked at his watch or at the compa.s.s, both of which he carried around his wrist. Intently the men all watched the signboard on the wall in front of them. The storm without made itself felt even in the depth. Every motion of the water caused the submarine to rock up and down and up and down again.

Jack found himself thinking of the advantage of the man on board a warship. He, at least, could go down with a last look at the world about him. Below, nothing could be seen, nothing could be heard. If the submarine went down, all would suffocate in the darkness beneath the water.

It was plain to Jack that Frank, as well as all the sailors and officers, was thinking along similar lines. The expression on all faces was plain proof of it.

Suddenly the sailors sprang forward, forgetting in an instant heat, bad air and discomfort. Following the gaze of the sailors, the lads turned their eyes to the signboard. There, as if by magic, had sprung up the word:

"Attention!"

The officer in command of the torpedoes had his hand on the lever which would release the first deadly projectile already in the tube. The sailors made ready to launch the second as soon as the first was gone.

Several seconds pa.s.sed. Frank and Jack stood in deathlike stillness. Both realized the tragedy that was about to be enacted, and both were aware of their powerlessness to avert it.

Into the minds of both flashed a thought of springing upon their captors, but each, after a moment's reflection, realized the futility of such an action. It would merely delay the firing of the first torpedo.

And so they stood while the seconds pa.s.sed, the heart of each in his throat. Suddenly the first sign on the board disappeared. A moment later and a second command appeared. Frank and Jack read it simultaneously, and both started forward with a cry.

The word that now stared them in the face, in red, glowing letters, was:

"Fire!"

With a single jerk, the officer released the first torpedo, even as both lads, unable to endure the suspense and inaction any longer, leaped upon him. There was a short, metallic click, the noise of water rushing into the empty tube, and it was over. The first torpedo had sped on its errand of destruction and death.

The German officer turned just in time to grapple with Jack, who was now upon him.

"Seize them, men!" he cried, and struck out sharply at the lad.

But Jack was too quick for him, and his right fist went crashing into the German's face. Frank was with him now, and the two turned to face the onrushing sailors.

Both struck out rapidly, but in spite of their resistance, they were soon overpowered by the numerical superiority of their foes, and thrown to the floor.

There, realizing the uselessness of further struggling, they gave up and lay still.

The German officer, having struggled to his feet in the meantime, now approached and stood over them. Perceiving they were no longer offering resistance, he motioned the sailors to let them up.

The lads arose and faced the officer.

"I realize your position better than you are probably aware," he said, speaking coldly, "and for that reason I shall overlook your attack upon me. I would have done as you did. I could not stand by and see a German ship sent to the bottom without raising a hand to prevent it. Go to your cabin, sirs." The boys bowed, and obeyed.

But while the boys were scuffling with the German officer and some of the sailors, others had pushed a second torpedo into the tube. And a sailor shouted, making himself heard by dint of a very powerful voice: "Did we hit her?"

Instinctively all kept count--one hundred meters, two hundred meters, three hundred, four hundred. Under the water no sound penetrated. Waiting was all that could be done. For a few moments nothing happened.

Then, suddenly, every man on the boat, Jack and Frank in the cabin, the captain, officers and all, were almost thrown from their feet by a terrific jerk of the submarine. Another jerk, and still another.

Then the submarine rolled as before--evenly. A moment and the regular purring of the engines was heard again. The submarine moved rapidly eastward.