The diving-suits were a very clever invention. They were superior to the old style for the fact that the diver had free use of his limbs and was hampered by no life-line or tube.

34Frank gave instruction to Barney and Pomp to remain aboard the Diver and keep a good watch of the two divers all the while. Then he helped Wade to don his suit and put on his own.

They were now ready to leave the boat.

This was accomplished in an ingenious manner. Of course, it would be impossible to merely open a door and step out.

Water would rush in and flood the cabin.

But Frank had provided a vestibule with two doors, one opening into the cabin and the other out on deck.

He had merely to enter the vestibule and close the cabin door. Then, by turning a valve, the vestibule would fill with water. It was easy then to open the outer door and walk out.

The return was accomplished much the same, though the pressure of a lever set the force-pump at work and cleared the water from the vestibule in quick time.

Frank and Wade entered the vestibule, and a few moments later were out on the vessel’s deck.

They clambered down the side and stood upon the pavement of the sunken city.

It was a strange sensation.

Probably no other men living could boast of the same experience. Down the street of the sunken city they walked.

It required Wade some little time to get used to the pressure, he being inexperienced.

But soon he had overcome the unpleasant sensation and was quite himself again. Together they strolled along the thoroughfare.

There was no conversation, for one could not have heard the other speak at that depth. Moreover, the helmets deadened the sound.

But conversation could be carried on by placing the two helmets close together and shouting. This was only resorted to in case of necessity.

The buildings of the sunken city were of two stories only and not at all pretentious—like the ruins of Palenque.

But there was one higher-arched structure, just back from the street, which claimed their attention.

There was a quantity of curious carving and scroll-work in its front. Frank concluded that it must be either a palace or a temple.

He was determined to ascertain.

Motioning to Wade he entered the place. The scientist was not slow to follow him.

Each wore upon his helmet a small electric globe. This made objects plain in the place.

35As they passed through the great portico it was easy to see at once what sort of a place it was. For a moment they were spellbound.

It was unquestionably a temple.

In front of them was a broad dais of stone. Upon this there rested a gigantic and grotesque image. It was plainly an idol.

The ancient inhabitants of the sunken city were then idolators. This fact was settled.

The idol was fully fifteen feet in height, and in shape was a cross between a sphynx and satyr. Its eyes were of some brilliant stone.

Around the temple were other idols of various sizes. Each had its dais, and there were the worn hollows in the stone made by the knees of kneeling thousands.

Frank placed his helmet close to Wade’s and shouted:

“Is this discovery of value to you?”

“Much!” replied the scientist; “it establishes the fact of idolatry, and also that these people were much like the Aztecs and worshiped the same gods. There are the idols Quetzal and Quetzalcoatl. They are Aztec gods.”

“That is certainly a great point,” replied Frank. “Yonder I can see some hieroglyphics on a stone. Is it possible to read them?”

“I am not familiar enough with Aztec cryptography,” said Wade. “I shall not attempt it.”

But another discovery was made.

Before the large idol was a broad and richly carved altar. Below it was a pit for the reception of the blood of the victims.

The two explorers gazed upon this gruesome object with a thrill.

“Many a poor wretch has gone to his doom on that stony surface,” declared Frank. “What barbarity!”

“True,” agreed Wade; “the ancient ideas of sacrifice were something simply savage.”

No small object of any kind of metal could be found. Every vestige of any material but stone had been absorbed by time and the water.

So Wade could find no other specimen to take with him but a small idol, which he placed in his pocket.

“I shall keep this for a talisman,” he declared. “Perhaps it will bring me good luck!”

“I believe I will do the same,” said Frank; “so here goes.”

He also took one of the idols. Then they left the temple.

Once out upon the street again they began to look for another object of interest.

36This soon turned up.

Passing through a sort of peristyle they c............