"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.

"Yes, m'sieur," she said a few moments later. "They are all dangerous.
They do not fear to use the knife or automatic pistol when cornered.
For myself, I simply move about Europe and make discoveries as to where
lit