Their progress was slow, for the water hampered their movements and each one had some of the dynamite to carry. The footing, too, was insecure, for the icy bed of the ocean was slippery.

As they were huddled together, the professor in the lead, and their lamps making a faint illumination in the darkness, they suddenly became aware of a great shadow over them. They looked up, and their hearts nearly ceased beating as they saw a gigantic sperm whale right over them, and between the ice. The terrible animal had observed them also, and, food being scarce in those frigid regions, had evidently made up its mind to dine on some choice morsels.

The whale was nearly as large again as the submarine, and to the frightened voyagers seemed more immense than a house. With slow motions of the flukes the animal placed itself right over the boys and men, ready to rush at and take them into its terrible maw.

Old Andy, who alone seemed to retain his presence of mind, stepped to the front. The professor and the boys wondered what he was going to do.

Then Andy held up one of the electric guns.

Always thinking of his chosen calling, the old hunter had picked up the weapon as he was leaving the _Porpoise_. He waited until the whale was within a short distance, so close in fact that the small eyes, out of all seeming proportion to the rest of the big body, could be seen. Then Andy fired one of the explosive bullets straight into the open mouth that was fringed with rows of the springy bone that is a part of a whale's eating apparatus.

The shot took effect, and made a vital wound. In its death struggles the beast lashed the ocean to foam, and, but for the fact that Andy as soon as he fired the shot crouched down, pulling the others toward the floor of ice, they might all have been killed.

The whale turned and made a rush in the opposite direction to that of the divers. This was a welcome sign to the professor, for he knew the animal was seeking open water and this told him it must be somewhere in the vicinity.

Their hearts still beating loudly from the closeness of death, the adventurers continued their way. On every side were fish, big and little, and, though some of the larger ones thrust themselves to the men and boys, as if wondering what strange creatures they were, none of them offered to attack.

Led by the professor they made a complete circuit of the ship that was held fast in the ice. As the inventor had surmised, the _Porpoise_ was nipped only above and below. If she could be freed at either of those points she could rise to the surface, or sink down under the ice.

After making a careful examination of the position of the craft, Mr.

Henderson motioned to have the dynamite placed on the ice, in front of, and about two hundred feet away from the nose of the ship.

He connected the cartridges with the fuse and wires that were to explode them, and then, taking the free end, he started back toward the ship.

Washington was on the watch for them, and operated the diving chamber.

Soon the four were back in the _Porpoise_.

"Now to see if our plan will work," said Mr. Henderson. "I am relying on the well known downward force of dynamite to blow a hole in the bottom part of the ice, so that we can drop below."

"Why not make a hole above so we can rise and escape?" asked Bill.

"Because," replied the professor, "we are now in the region of perpetual ice. The ocean above us is one fast floe, or a number of smaller ones, so that, in any event our progress would be impossible. But we can sail far enough down under water to escape all the ice. That is the purpose of the _Porpoise_. That is why I built her. We will now begin on the last part of our voyage; that is if we can get free of the fearful grip of this sea of ice."

There was little they could do to protect themselves. They would either escape or be blown to pieces in case the explosive exerted too great a force. They all put on life preservers to guard against the contingency of the _Porpoise_ being ripped apart and themselves cast into the water, yet they realized that without their ship, they could live but a little while in the ice-filled water near the south pole.

The professor saw that everything was in readiness. He hesitated a moment and looked at the electric b.u.t.ton in his hand, for this time the dynamite was to be detonated by a battery. How much might depend on one push of the finger!

There was a slight movement to the muscles of the professor's hand. Then it seemed as if a thunderbolt had fallen into the midst of the ocean about them.

There was a dull rumble, but the confined s.p.a.ce and the thick walls of the ship shut most of it out. It was followed by a sickening dizzy motion to the submarine. She seemed about to roll over and those in her grabbed frantically at the sides. The next instant the craft plunged down, down, down, into the water which was filled with broken cakes of ice, that rattled against the steel sides, like peas in a pan.

Down and down the _Porpoise_ went, for her tanks were full. More and more rapidly she continued to sink, until it seemed she would fetch up in the deepest cavern of the ocean.

"We's gwine t' Mars Davy Jones's locker, suah!" Washington exclaimed as he looked at the depth gages.

[Ill.u.s.tration: THEY WERE IN THE MIDST OF A GRAVEYARD OF WRECKED SHIPS.--_Page 200._]

"Has the experiment succeeded?" asked Andy of Mr. Henderson.

"I think so," was the answer. "At any rate we are free from the ice, temporarily at least. We are sinking down through the hole the dynamite made, just as I hoped we would."

"Where will we end up?" asked Jack.

"No one knows," replied the captain. "But I would say--"

At that instant the ship stopped sinking and brought up with a b.u.mp.

"I should say we were at the end of this part of our journey," finished the inventor.

He turned off the cabin lights and lighted the search lamps that threw a gleam so the water could be looked at from the bull's-eyes windows. The sight that met their gaze was an astonishing one.

They were in the midst of a graveyard of wrecked ships, and, on every side, scattered over the ocean bed, were the broken hulks that had once been stately vessels.

CHAPTER XXV

CAUGHT BY SEA SUCKERS

"What sort of a place is this?" asked Andy, as he gazed at the last resting spot of the big ships.

"They have probably drifted here with the ocean currents, become caught in the ice and have remained here hundreds of years," said Mr.

Henderson. "Some of the ships are very old, and, by their build must have sailed the waters centuries ago."

"Maybe some of them are treasure ships," suggested Jack.

"They might be," admitted the professor.

"Then we'll go aboard and get the gold," spoke Mark.

"I'm afraid you'll be disappointed," went on the inventor. "In the first place most treasure ships are looted before they sink. And it would be very dangerous for any of us to venture to explore those hulks."

"Why?" asked Jack.

"Because they are rotten, and liable to fall to pieces any minute. If you happened to be in one at the time you would be caught in the wreckage and eventually drowned even though you had on a diving suit.

Then, again, the ice here is constantly shifting about, and a sudden motion of the under-water floe might carry you hundreds of miles away.

So we will not try to hunt for any fortunes on the sunken ships."

With this the boys were forced to be content. They stood at the small windows looking at the skeletons of ships that lay on every side of the _Porpoise_. Some of the craft were big steamers, and others were small sailing vessels. A few had jagged holes in the hulls, showing how they had been damaged. A few stood upright, with sails all set, as if disaster had suddenly come upon them.

"Well, what is the next move?" asked Andy after a pause. "Are we going to stay here?"

"We are going to find the South Pole," spoke Mr. Henderson suddenly.

"That is what I set out to do, and I am going to accomplish it if possible. We have had many accidents and a harder time in some respects than when we made our trip to the north in the air ship. But I am sure we shall succeed. Start the ship to the south, Washington."

"But we may run into an iceberg," objected the old hunter, who was inclined to be cautious.

"I think not," answered Mr. Henderson. "I believe we are on a sort of level plane between two vast upper and lower fields of ice. We can go freely in any direction excepting up or down."