"Nay," replied the Sheik, "for this is but the outer court."
"Is the fire always issuing from that crater?" inquired St. Just when they had retraced their steps to their companions. "And will it take long to destroy what remains of the city?"
"Years, at the rate it goes on now; for it is not always burning actively; sometimes for long periods it only smoulders. But, possibly, only hours, should there be a great increase in the outpour of the lava."
"And, if the lake above fell in on top?" suggested St. Just laughing.
"Seconds; there would be such an explosion as the world has never yet seen."
Their torches, which they had extinguished when they had been no longer needed, were now relighted, and they made their way back as rapidly as possible, musing in silence on all that they had seen.
The dawn of another day was breaking when they emerged on the spot from which they had started on the subterranean journey; and at once they started for the camp.
Three days later, St. Just left for Cairo, resolved first to marry Halima, and then, to gain possession of the treasure and return to France at the first opportunity. He had made some rough plans of the place, unknown to the Sheik, and these he took with him when he set out for Cairo.
CHAPTER XIII.
It was on the fifth of March that St. Just started on his return journey to Cairo, accompanied by an escort of twenty of the old Sheik's followers and the lad Mahmoud, to whom, on account of his alertness and fidelity, he had become much attached. He was the bearer of a letter written in Arabic, from the Sheik to Buonaparte, its purport being that the wily Ibrahim, while declining to give any active assistance to the French Commander-in-chief, agreed, on the other hand, not forcibly to oppose him.