The barrister had more than once surprised his companion during the previous night, but this time Gaultier seemed to be more annoyed than startled. "If you know all these things," he said stiffly, "I don't see why you should bother me to get you the information. I certainly gathered from your remarks that the only acquaintance you had with Hussein-ul-Mulk was obtained from the newspapers, and that individual himself has the best of reasons for not publishing his address broadcast." Brett smiled. "You mean," he said, "that Hussein-ul-Mulk does live at No. 11, Rue Barbette." "Why, of course he does," was the irritable answer. "That is very odd," said the barrister. "It was a mere guess on my part, I assure you." His assurance evidently did not weigh much with Captain Gaultier, who replaced the note-book in his pocket, and obviously cast about in his mind for a convenient excuse to take his departure. Brett knew exactly what was troubling him. "I am quite in earnest," he said, "in telling you that I simply hazarded a guess at the address. To prove that this is so, I must place you in possession of certain incidents which took place after we parted at the Gare du Nord." Rapidly but succinctly he told the amazed King's messenger of the chase in the cab across Paris, and how he (Brett) had followed the Frenchman who was tracking Gaultier's movements so closely. "You will understand," he concluded, "that, in view of my preconceived theory, it was not a very far-fetched assumption to connect Hussein-ul-Mulk with the house in the Rue Barbette into which your spy vanished." "Well," gasped his astonished hearer, "I must say, Mr. Brett, that I owe you an apology. I really thought at first you were fooling me, whereas now I learn that you simply kept your eyes open much wider than other people, perhaps. Nevertheless, you have given me a genuine explanation of circumstances that were otherwise puzzling. For, do you know, I heard about that chap calling at the Embassy last night. The incident was unusual, to say the least, but I paid little attention to it, and certainly failed altogether to connect it with your visit to Paris. Even yet I do not see what reason anyone can have for shadowing my movements." "I regard it as mere chance. I imagine that our fellow-passenger in the train caught the name of Hussein-ul-Mulk in our conversation, and this decided him to shadow your movements, by means of the confederate who awaited his arrival at the station. As it happened, they simply hit upon the wrong person. It might have paid them much better to follow me. The outcome of the blunder is that I am in a fair way towards ascertaining all I want to know about them, whereas, up to the present, they do not even suspect my existence as an active agent in the affair." "Well, now, in what way can I help you regarding Hussein-ul-Mulk?" "Can you introduce me to him?" "In what capacity?" Brett reflected for a moment before replying.