Two knocks.
"B."
Twenty knocks.
"T."
Carmen now read the meaning of this:
"There is an iron door under the wall decoration."
Coucou soon found the secret door.
At the end of five minutes Fanfaro, Bobichel and Gontram were again with their friends. In a few words Carmen related what had brought her there, and showed the letter she had taken from Larsagny.
"In Courbevoie!" cried Gontram. "How shall we find Spero there?"
"I know the house," said Carmen; "it belongs to the banker, and I believe we shall find the vicomte there."