In reply he was perfectly frank with her.  He told her of the suspicion against him because of the affair of the Villa Amette.

“Ah!” she replied, her manner changing, “I have heard that Mademoiselle was shot, but I had no idea that you had any connexion with that ugly business.”

“Yes.  Unfortunately I have.  Do you happen to know Yvonne Ferad?”

“Of course.  Everyone knows her.  She is very charming.  Nobody knows the truth.”

“What truth?” inquired Hugh quickly.

“Well—­that she is a marque de ce.”

“A marque de ce—­what is that?” asked Hugh eagerly.

“Ah! non, m’sieur.  I must not tell you anything against her.  You are her friend.”

“But I am endeavouring to find out something about her.  To me she is a mystery.”

“No doubt.  She is to everybody.”

“What did you mean by that expression?” he demanded.  “Do tell me.  I am very anxious to know your opinion of her, and something about her.  I have a very earnest motive in trying to discover who and what she really is.”

“If I told you I should offend Il Passero,” replied the girl simply.  “It is evident that he wishes you should remain in ignorance.”

“But surely, you can tell me in confidence?  I will divulge nothing.”

“No,” answered the girl, whose face he could not see in the shadow.  “I am sorry, M’sieur Brown”—­she had not been told his Christian name—­“but I am not permitted to tell you anything concerning Mademoiselle Yvonne.”

“She is a very remarkable person—­eh?” said Henfrey, again defeated.

“Remarkable!  Oh, yes.  She is of the grande monde.”

“Is that still your argot?” he asked.

“Oh no.  Mademoiselle Yvonne is a lady.  Some say she is the daughter of a rich Englishman.  Others say she is just a common adventuress.”

“The latter is true, I suppose?”

“I think not.  She has le clou for the eponge d’or.”

“I do not follow that.”

“Well,” she laughed, “she has the attraction for those who hold the golden sponge—­the Ministers of State.  Our argot is difficult for you, m’sieur—­eh?”

“I see!  Your expressions are a kind of cipher, unintelligible to the ordinary person—­eh?”

“That is so.  If I exclaim, par exemple, tarte, it means false; if I say gilet de flanelle, it is lemonade; if I say frise, it means a Jew; or casserole, which is in our own tongue a police officer.  So you see it is a little difficult—­is it not?  To us tire-jus is a handkerchief, and we call the ville de Paris Pantruche.”

Hugh sat in wonder.  It was certainly a strange experience to be on a moonlight ramble with a girl thief who had, according to her own confession, been born in Paris the daughter of a man who was still one of Il Passero’s clever and desperate band.