Canolles went to his room, taking every possible precaution not to be seen by Nanon; and having made sure that he was alone, locked himself in.
At the head of his bed were the arms of the lords of Cambes, upon a tapestry hanging surrounded by a band of gold.
Canolles raised the band, which was not attached to the tapestry, and disclosed the crack of a door. With the aid of the key which accompanied the viscountess's letter, he opened the door, and found himself confronted by the gaping orifice of a subterranean passage.
For a moment Canolles was struck dumb, and stood motionless, with the sweat pouring from his brow. This mysterious opening into the bowels of the earth terrified him in spite of himself.
He lighted a candle and prepared to inspect it.
First, he descended twenty steep stairs, then kept on down a gentler slope farther and farther into the depths.
Soon he heard a dull, rumbling noise, which alarmed him at first, because he could not think to what cause to attribute it; but as he went forward he recognized it as the roar of the river flowing above his head.
The water had forced its way through the arch in divers places at one time or another, but the crevices had evidently been detected in time and filled with a sort of cement, which became harder in course of time than the stones it bound together.
For about ten minutes Canolles heard the water rolling over his head; then the noise gradually died away until it was hardly more than a murmur. At last even the murmuring ceased, to be succeeded by perfect silence; and after walking a hundred feet or more in the silence, Canolles reached a staircase similar to the one by which he had descended, and closed at the top by a massive door which the united strength of ten men could not have moved, and which was rendered fire-proof by a thick iron plate.
"Now I understand," said Canolles; "she will await Nanon at this door and help her to escape."