But where are we ?" The Persian lit his lamp again and flung its rays down two enormous corridors that crossed each other at right angles.
"We must be," he said, "in the part used more particularly for the waterworks.

I see no fire coming from the furnaces." He went in front of Raoul, seeking his road, stopping abruptly when he was afraid of meeting some waterman.

Then they had to protect themselves against the glow of a sort of underground forge, which the men were extinguishing, and at which Raoul recognized the demons whom Christine had seen at the time of her first captivity.
In this way, they gradually arrived beneath the huge cellars below the stage.

They must at this time have been at the very bottom of the "tub" and at an extremely great depth, when we remember that the earth was dug out at fifty feet below the water that lay under the whole of that part of Paris.[4] The Persian touched a partition-wall and said: "If I am not mistaken, this is a wall that might easily belong to the house on the lake." He was striking a partition-wall of the "tub," and perhaps it would be as well for the reader to know how the bottom and the partition-walls of the tub were built.

In order to prevent the water surrounding the building-operations from remaining in immediate contact with the walls supporting the whole of the theatrical machinery, the architect was obliged to build a double case in every direction.