All received this word with a cry of joy.

In a few moments the Scorcher was descending to the next plateau. Here a revelation was accorded the adventurers as Frank had promised.

For there, just beyond the fringe of trees, was indeed visible quite plainly the white ruins of a town.

It was surrounded by a demolished wall of stone, resembling marble. All about this were trees of a pomegranate and mulberry type or species. It was plain that great gardens had once surrounded the town.

The buildings were all shattered and riven, as if by the force of an earthquake or a bombardment. It was evil dent that the city was destroyed by some force as yet unknown.

And the inhabitants—were they destroyed also?

With great interest and powerful curiosity the voyagers watched the ruined city as they drew nearer to it.

A long, level prairie now alone intervened. To cross this did not require a long space of time.

But the Scorcher now struck into what looked like a sort of road, leading down to the town gates. Part of the way it was fringed with a hedge of firs.

And at intervals the ruins of strange-looking houses were seen upon either hand. The adventurers regarded them wonderingly.

On ran the Scorcher at a fair rate of speed.

And it followed that very soon the machine crossed a causeway of white stone and rolled between two high pillars into the main street of the town.

It was noted then how curiously the place was laid out.

The entire town described a circle; all the streets beginning at the gate and extending in circles about a hollow or amphitheater in the center.

It was a strong reminder of a coliseum, the houses occupying the position of the seats. In the center of the public square, or circle, rather, there had stood a tall shaft of stone, fully one hundred feet high.

Doubtless this was a monument, commemorating some heroic deed or mighty occasion. In this sentiment, at least, the Polar people resembled their civilized neighbors beyond the ice belt.

“By Jove!” exclaimed Randall, “these people were the equal of the ancient Aztecs. Their architecture shows that.”

“They may be our equals,” said Frank. “We have as yet no means of proving the contrary.”

“That is very true.”

There were some obstruction in the street of the Polar city, but the Scorcher managed to pick its way along without great difficulty.

Not until the central part of the city was reached did the machine stop. Then Frank stepped out on deck, and cried:

“Well, friends, here we are. We have accomplished the great feat of crossing the Antarctic barrier and invading the Polar Continent. We have discovered a ruined town, and evidence that this was once an inhabited region, though now abandoned. Let us, therefore, set foot on Polar soil and devote some time to exploration.”

Cheers followed this declaration, and all leaped over the rail.

There was little need of guarding the Scorcher, for no living foe was in the vicinity. Barney and Pomp began a frolic on the green turf, while Frank, with Randall and the sailor, began the exploration.

They scrambled over the ruins of the building, and were impressed with the fact that their architecture had been of a tasty kind.

“These people were not savages,” declared Frank. “They understood the arts. Look!”

He picked up an object which all saw at once was a helmet or head-dress. It was basinet shaped, and of a strange kind of bronze-like metal.

“What is the metal?” asked Randall, as he examined it. Then he gave a sharp cry.

“What is the matter?” asked Frank.

“Do you know what kind of metal this is?” asked Randall.

“No.”

Frank knew that the other was an expert metallurgist. So he awaited the announcement with interest.

“Well,” said Randall, slowly, “its chief component part is gold!”

“Gold!”

“Yes, also in the alloy is silver and iron. That proves that these people knew the use of metals. It proves more!”

“Well?”

“That gold is one of the common ores of this region.” Frank and Wendel gave a start. Their eyes shone.

How easy it is to arouse the gold fever in the human composition! It is as natural as breathing.

But Frank regained himself.

“That adds to the value of our discovery!” he cried. “At no distant day, doubtless, gold-seekers will forsake Australia and Africa for the Polar mines.”

“Exactly! I have no doubt that rich deposits exist here!”

“Well,” said Frank, “they are of little use to us just now. Ha! What have we here?”

As he spoke the young inventor had taken a step forward.

At his feet yawned a deep pit. There were stone stairs descending into it.

What seemed like a crypt, or underground chambers, were doubtless below. This reflection was enough.

Exploration was the order, so Frank hesitated no longer but prepared to descend into the place.

Randall waited curiously for Frank to descend. Then he followed.

They stood in a little square chamber, apparently cut out of solid rock. Beyond was a narrow passage, but black as Erebus.

“What is it?” asked Randall. “It looks like a tomb.”

“And so it may be,” agreed Frank, “or perhaps a treasure vault. At any rate, we will explore it.”

He stepped into the dark passage, but before he had proceeded ten feet he abruptly halted.

In the darkness ahead there blazed two fearful balls of fire. Instinctively Frank shivered.

He knew that some fierce animal—a panther or wolf—had made this hole its den.

He was face to face with the creature, and it was by no means a despicable foe or an enviable situation. In this dark place it would not be easy to defend one’s self.

A deep, hoarse growl came from the depths. Then Frank gasped:

“A bear!”

He retreated backward precipitately, hoping to reach the outer chamber, but the glaring eyeballs were close upon him.

Frank had for weapons only a revolver and a knife.

He drew the revolver and fired point blank at the eyes. Before he could fire again it was struck from his grasp by a huge paw, and he had to fall back on his knife.

Another blow of the paw brought him to his knees, and he was obliged to clinch with his foe.

Meanwhile Randall and Wendel had grasped the situation.

The former tried to drag Frank from the dark passage, and in the struggle both man and bear emerged. This was a better chance for Frank.

The bear was of a monster black species. Frank was driving the knife into its carcass, but it seemed to have no effect.

It was Wendel who saved the day.

He luckily had his rifle with him. Rushing forward he placed it at the bear’s head and fired point blank.

The ball crashed through bruin’s brain and ended the struggle. Frank detached himself from the brute’s embrace.

By a miracle he was comparatively unharmed, having only a few hard scratches to show for his struggle.

But it was a close call.

“By Jupiter!” gasped Randall, “I thought you were done for that time, Frank.”

“I owe my life to you,” said Frank, gripping Wendel’s hand.

“I am glad of that, mate,” replied the sailor, heartily.

“Do you think there are any more bears in there?” asked Randall.

“No,” replied Frank, “but it is well to use precaution. Let us proceed with care.”

Once more they crept into the passage. In a few moments they stood in a gloom-filled chamber.

At one end of this was another pit and stairs. They evidently led down to deeper regions.

It was too dark to proceed farther at haphazard. So Frank turned about and said:

“If one of us can go back to the Scorcher and get an electric lantern I think we can go farther.”

“I’ll do that,” agreed Wendel, and away he went.

It was not long before he returned with the lantern. This had a powerful burner and lit up the subterranean chambers fully.

Down the second flight of steps the explorers now proceeded. A remarkable discovery was in store for them.

Down and down a winding way they went.

Soon it was seen that the walls of the passage were of natural conformation and that they were really in a cavern.

It trended downward for what seemed an interminable distance. Then suddenly a startling surprise was accorded all.

For they had emerged into a mighty, high-domed cavern chamber. Its limits could not be seen.

But it was nearly occupied with a mighty subterranean lake. The water flashed in the lantern’s glare.

“An underground sea!” cried Randall. “What a wonder!”

“And access to it by the Polar people,” mused Frank. “What was their purpose?”

“Perhaps to get water or to fish,” suggested Wendel. “Eh! what kind of a craft is this?”

As he spoke he bent down over a sort of coracle which lay in the sands. Paddles were against the thwarts just as it had been left by its former owners.

The little craft was examined and found to be quite staunch.

But just at that moment Randall gripped Frank’s arm.

“Look!” he whispered.

He pointed across the domed lake. There was a strange leaping, fantastic glare of light. It appeared at intervals and was intensely weird and fanciful in its shapes.