The scientist and Ben Hassim finally did manage to attain to the foot of the mountain wall, which rose unbroken from the plain, on the fifth day. But their supply of water was exhausted, they were semi-delirious. For two days they travelled along the base of the wall, seeking some pass or valley which pierced the barrier.

At length on the seventh day they came upon a stone-paved road and, scarcely able to believe the evidence of their senses, they began to follow along it into the mountains. Before proceeding far, however, they were overcome by fever and thirst and fell insensible. In this condition, they were found and rescued.

Upon recovery they found themselves amidst great stone ruins of ponderous architecture, in the midst of a luxuriant valley watered by a broad stream encircling one side, which emerged from a tunnel in the mountains and disappeared again into the mountains, not to reach the surface more.

Their rescuers were kindly men, several of whom possessed a good command of English, and they were white. But as Professor Souchard’s knowledge of English was strictly limited, they could not understand each other well.

However, while being nursed back to strength, the scientist managed to make out that his rescuers were political refugees from another city in the heart of the mountains known as Athensi, and that in this city and the plateaus surrounding it dwelt a white race of semi-civilized people ruled over by a religious Oligarchy. His rescuers were men of superior intelligence and a high state of culture and that they had travelled about the world was apparent. With his slight knowledge of English and a smattering of their tongue which he picked up, he was able to come to that conclusion.

To him it became apparent that the ruined city of Korakum, overgrown by rank jungle growth and in the midst of which the Athensian exiles cultivated little patches of garden, was the city he had been seeking. But the little he could learn of Athensi fired his imagination. Apparently, at some dim age in the past the settlers of this ruined city which had been called Korakum had withdrawn into the mountain country and built Athensi, where were palaces, temples, a vast Coliseum, above all, a great Library housing thousands of papyrus rolls.

If he could only gain access to Athensi, thought Professor Souchard, what wonders and mysteries of the ancient world, perhaps of a civilization existing in Atlantis before the Flood, would be revealed.

However, on his recovery, the exiles told him it was best for him to depart before the Athensian authorities discovered his presence, as they wished to preserve isolation from the outside world and did not want their secret discovered. Therefore, after supplying him with water and food, they started him and Ben Hassim on the return journey.

Well did Jack recall the arrival of Professor Souchard at his father’s home on Long Island with this tale. Mr. Hampton, himself an explorer and engineer of wide reputation, had been enthusiastic. He had promised the scientist, whose funds had become exhausted and who was unable to obtain backing for further explorations in war-exhausted Europe, to finance an expedition to Athensi.

With this promise, Professor Souchard had returned to Africa, and as soon as he could put his affairs in shape for prolonged absence, Mr. Hampton had followed. With him he had taken Jack and the latter’s close chums, Bob Temple and Frank Merrick.