`There are things happening here, Mr. Commissary, which we are unable to explain.'

And the two faces disappeared.

`Thank you for the information, gentlemen,' said Mifroid, with a jeer.

But the stage-manager, holding his chin in the hollow of his right hand, which is the attitude of profound thought, said:

`It is not the first time that Mauclair has fallen asleep in the theater. I remember finding him, one evening, snoring in his little recess, with his snuff-box beside him.'

`Is that long ago?' asked M. Mifroid, carefully wiping his eye-glasses.

`No, not so very long ago....Wait a bit!...It was the night ... of course, yes...It was the night when Carlotta - you know, Mr. Commissary - gave her famous `co-ack'!'

`Really? The night when Carlotta gave her famous `co-ack'?'

And M. Mifroid, replacing his gleaming glasses on his nose, fixed the stage-manager with a contemplative stare.

`So Mauclair takes snuff, does he?' he asked carelessly.

``Yes, Mr. Commissary....Look, there is his snuff-box on that little shelf....Oh! he's a great snuff-taker!'

`So am I,' said Mifroid and put the snuff-box in his pocket.

Raoul and the Persian, themselves unobserved, watched the removal of the three bodies by a number of scene-shifters, who were followed by the commissary and all the people with him. Their steps were heard for a few minutes on the stage above. When they were alone the Persian made a sign to Raoul to stand up. Raoul did so; but, as he did not lift his hand in front of his eyes, ready to fire, the Persian told him to resume that attitude and to continue it, whatever happened.

`But it tires the hand unnecessarily,' whispered Raoul. `If I do fire, I shan't be sure of my aim.'

`Then shift your pistol to the other hand,' said the Persian.

`I can't shoot with my left hand.'

Thereupon, the Persian made this queer reply, which was certainly not calculated to throw light into the young man's flurried brain:

`It's not a question of shooting with the right hand or the left; it's a question of holding one of your hands as though you were going to pull the trigger of a pistol with your arm bent. As for the pistol itself, when all is said, you can put that in your pocket!' And he added, `Let this be clearly understood, or I will answer for nothing. It is a matter of life and death. And now, silence and follow me!'

The cellars of the Opera are enormous and they are five in number. Raoul followed the Persian and wondered what he would have done without his companion in that extraordinary labyrinth. They went down to the third cellar; and their progress was still lit by some distant lamp.

The lower they went, the more precautions the Persian seemed to take. He kept on turning to Raoul to see if he was holding his arm properly, showing him how he himself carried his hand as if always ready to fire, though the pistol was in his pocket.

Suddenly, a loud voice made them stop. Some one above them shouted: