He looked about him for a few moments and then turned and walked back to his companions, who were already crowding towards the opening with faces glad with new hope and drawing deep breaths of the life-giving air, which the mysterious alchemy of Nature had restored unchanged to the earth. He stopped them with a gesture and said—

“Don’t go out yet till we have made the tunnel safe. You will find an awful change out yonder. Aeria is no longer a paradise. It is only a swamp surrounded by naked rocks!”

And so they found it to be when they at length passed out through the tunnel and stood upon the black oozy shores of the dreary lake which still half filled what had once been the lovely land of Aeria.

The once verdure-clad mountains rose up bare and gaunt and blackened, a vast circle of ragged rock, unrelieved by a blade of grass or a single tree of all the myriads that had clothed their slopes three days before. It seemed as though the clock of Time had been put back through countless ages and the world was once more as it had been before the first forms of life appeared upon it.

But still the air that fanned their cheeks was fresh and warm and sweet, and the afternoon sun was shining across the western peaks out of a cloudless sky of purest blue. The calm had come after the storm and the world was waiting to begin its life anew. The Alma and the Isma had utterly vanished, and were probably buried deep in the black slimy mud. Of the city of Aeria not a vestige was visible.

The first thing that Alan did as soon as the last momentous question had thus been asked and answered was to ask his father to order one of the smaller air-ships, which had been stored in sections in the cavern, to be put together and charged with motive-power as rapidly as possible.

“Certainly if you wish it,” he replied; “but what is your reason for being in such a hurry to reassert your empire of the air?”

“I can tell you now,” said Alan in reply, “what there would have been no need to tell you if, well, if we had not been able to leave the caverns. Just after sunrise on the last day of the battle Bruno Vincent brought the Orion as near as he could to the Alma and told me by signal that he had seen the Revenge leave the fight and head away at full speed to the southward and westward. That means, I think, that Olga’s courage failed her at the last and that she meant to try the forlorn hope of saving herself in her old stronghold at Mount Terror. I am going to see whether she is alive or dead.”

“And suppose by a miracle you should find her alive. What then?” said Alma, who had overheard his request, coming up to him and looking up into his face with melting eyes as she slipped her hand caressingly through his arm.

“The world is beginning its life anew in us, dear,” he replied with tenderness in his eyes but none in his voice, “and there shall be no snake in our Eden if I”—