I gave a start of surprise.  How on earth did he guess this?

“Yes!  I see I’m right,” he answered with a little laugh.  “Well, I knew it a long time ago.  Ah, you are astonished!  You should surely never allow yourself to be surprised by anything.  Now I will tell you how I come to know about the gems.  Some time ago a certain well-known lady of this city lost her jewel-case in a mysterious manner.  The affair was placed in my hands, and when I had exhausted Paris, I went to Amsterdam, en route if necessary for London.  You know our old friends, Levenstein and Schartzer?”

I nodded.  I had had dealings with that firm on many occasions.

“Well, as I went into their office, I saw the gentleman who has been paying his attentions to the lady we have been discussing, come out.  I have an excellent memory for faces, and when I saw him to-night entering the Cafe des Ambassadeurs, I recognized him immediately.  Thus the mystery is explained.”

He shrugged his shoulders and spread his hands apart, like a conjurer who has just vanished a rabbit or an orange.

“Has the man of whom we are speaking done very wrong?” he inquired.

“The stones he sold in London and Amsterdam belonged to himself and his two partners,” I answered.  “He has not given them their share of the transaction.  That is all.”

“They had better be quick about it then, or they are not likely to get anything.  It would be a very big sum that would tempt la belle Louise to be faithful for a long period.  If your employers really desire to punish him, and they are not in want of money, I should say do not let them interfere.  She will then nibble-nibble at what he has got like a mouse into a store of good things.  Then presently that store will be all gone, and then she will give him up, and he, the man, will go out and shoot himself, and she will pick up somebody else, and will begin to nibble-nibble just as before.  As I say, there will be somebody else, and somebody else, right up to the end of the chapter.  And with every one she will grow just an imperceptible bit older.  By and by the wrinkles will appear; I fancy there are just one or two already.  Then she will not be so fastidious about her hundred of thousand francs, and will condescend to think of mere thousands.  After that it will come to simple hundreds.  Then there will be an interval—­after which a garret, a charcoal brazier, and the Morgue.  I have known so many, and it is always the same.  First, the diamonds, the champagne, the exquisite little dinners at the best restaurants, and at last the brazier, the closed doors and windows, and the cold stone slab.  There is a moral in it, my dear friend, but we will not look for it to-night.  When do you intend to commence business with your man?”

“At once,” I answered.  “He knows that I am after him and my only fear is that he will make a bolt.  I cannot understand why he is dallying in Paris so long?”