Cimourdain, Guéchamp, and Radoub had gone down into the ravine. Gauvain had returned to the hall on the second story of the Tourgue, where the turning stone, the secret passage, and the iron door of the library were to be found; it was there that the sulphur match had been lighted by the Imânus, and there the fire had originated. Gauvain had brought with him twenty sappers. Their last resource was to force open the iron door. Its fastenings were terribly strong. They went at it with their axes, dealing violent blows. The axes broke. One of the sappers exclaimed,-- "Steel shivers like glass against that iron." In fact, the door was composed of double sheets of wrought-iron bolted together, each sheet three inches thick. Then they took iron bars and tried to pry the door open from below. The iron bars broke. "One would think they were matches," said the sapper. "Nothing less than a cannon-ball could open that door," muttered Gauvain, gloomily. "We should have to mount a field-piece up here." "But even then--" replied the sapper. For a moment they stood in despair, and their arms fell helpless by their sides. With a sense of defeat, these men stood in speechless dismay, gazing upon that door so awful in its immobility. They caught a glimpse of the red reflection from beneath it. Behind them, the fire was spreading. The frightful body of the Imânus was there, dread victor that he was. But a few minutes more, and the entire building might fall into ruins. What could they do? The last ray of hope was gone. Gauvain, whose eyes were riveted on the revolving stone and the opening through which the escape had been made, cried in the bitterness of his exasperation,-- "And yet the Marquis de Lantenac escaped through that door!" "And returns," said a voice. Against the stone setting of the secret passage appeared a white head. It was the Marquis. It was many a year since Gauvain had seen him so close at hand. He drew back. Every man present stood as if petrified. The Marquis held a large key in his hand; with one haughty glance he compelled the sappers who stood in his path to make way for him, walked at once to the iron door, stooped beneath the arch, and put the key into the lock. It creaked in the lock, the door opened, they saw the fiery gulf; the Marquis entered it. With head erect and steady step he strode forward. And those who looked on shuddered as their eyes followed his receding form. He had barely taken a few steps in the burning hall, before the inlaid floor, undermined by the fire and shaken by his tread, gave way behind him, setting a chasm between him and the door. The Marquis pursued his way, never once turning his head, and vanished in the smoke. Nothing more was seen. Had he succeeded in making his way; or had another fiery chasm opened under his feet; or had he but ended his own life? No one could tell. A wall of smoke and flames rose before them. Whether dead or alive, the Marquis was on the other side.