But the Zouave was interrupted by a strange sound like that made by a heavy hammer at some distance.
Madame turned pale.
"You know, Coucon, that I am not a coward, but I tell you I can't make out that sound. I have heard it now for some time."
"It seems to come from the cellar."
"Yes, that is what I think. But let us tell the friends."
They by this time had reached Jane's door, on which they knocked. No reply. Then, after knocking and listening, Madame said:
"We must go in!"
She opened the door, and both uttered a cry on finding the chamber empty. The iron panel had closed, and no one would have suspected its existence.
Coucon could not believe his eyes. He ran through every room, but those they sought had vanished. They had not gone out of the hôtel, for Madame had guarded it.