“Oh, nothing could be easier, sir,” replied Lecoq. “When the Widow Chupin and the accomplice had that interview at the station-house near the Barriere d’Italie, they both realized the necessity of warning Polyte. While trying to devise some means of getting to him, the old woman remembered her sister’s visiting card, and the man made some excuse to borrow it.” “Yes, such must be the case,” said M. Segmuller, approvingly. “It will be necessary to ascertain, however--” “And I will ascertain,” interrupted Lecoq, with a resolute air, “if you will only intrust the matter to me, sir. If you will authorize me I will have two spies on the watch before to-night, one in the Rue de la Butte-aux-Cailles, and the other at the door of the Hotel de Mariembourg. If the accomplice ventured to visit Toinon or Madame Milner he would be arrested; and then we should have our turn!” However, there was no time to waste in vain words and idle boasting. Lecoq therefore checked himself, and took up his hat preparatory to departure. “Now,” said he, “I must ask you, sir, for my liberty; if you have any orders, you will find a trusty messenger in the corridor, Father Absinthe, one of my colleagues. I want to find out something about Lacheneur’s letter and the diamond earring.” “Go, then,” replied M. Segmuller, “and good luck to you!” Good luck! Yes, indeed, Lecoq looked for it. If up to the present moment he had taken his successive defeats good-humoredly, it was because he believed that he had a talisman in his pocket which was bound to insure ultimate victory. “I shall be very stupid if I can’t discover the owner of such a valuable jewel,” he soliloquized, referring to the diamond earring. “And when I find the owner I shall at the same time discover our mysterious prisoner’s identity.” The first step to be taken was to ascertain whom the earring had been bought from. It would naturally be a tedious process to go from jeweler to jeweler and ask: “Do you know this jewel, was it set by you, and if so whom did you sell it to?” But fortunately Lecoq was acquainted with a man whose knowledge of the trade might at once throw light on the matter. This individual was an old Hollander, named Van Numen, who as a connoisseur in precious stones, was probably without his rival in Paris. He was employed by the Prefecture of Police as an expert in all such matters. He was considered rich. Despite his shabby appearance, he was rightly considered rich, and, in point of fact, he was indeed far more wealthy than people generally supposed. Diamonds were his especial passion, and he always had several in his pocket, in a little box which he would pull out and open at least a dozen times an hour, just as a snuff-taker continually produces his snuffbox.