The detective interpreted his silence as an admission of inability to find a satisfactory explanation of Mrs. Hillmer's absence. He went on: "Corbett is not at Monte Carlo." "So I imagined." "Well, it is a fact. The police have made constant inquiries for him at the Hotel du Cercle and elsewhere. Not the slightest trace of him can be found." "I was there myself, you know." "Yes, sir. I have not forgotten that. But it shows what a clever rascal the fellow is in concealing his identity. However, he could never have counted on my discovering that letter of his. Even if he is not in America we shall have some reliable data to go upon in answer to my queries." "There I fully agree with you. You will have done a great deal if you thoroughly clear up the mystery regarding Corbett. May I ask you to let me know the result?" "With pleasure, sir. And now, can I request a favor in return?" "Certainly." "Tell me, then, what is, in your opinion, the best way to find Mrs. Hillmer." Bruce did not expect to be thus openly challenged on the matter. It was one thing to withhold his own theories and discoveries from this representative of the majesty of the law, but quite another to refuse to help a detective with whom he was nominally working. Besides, Mrs. Hillmer had four days' start. It would take some time--possibly a telegram would not be sufficiently explicit--to obtain the desired assistance from the Continental police. Yes--in this instance, Mensmore must take his chances. "If I were you," said Bruce, slowly weighing his words, "I would inquire at the Continental booking-offices at Victoria and Charing Cross, and from the guards in charge of the morning mail trains on the 30th. In fact, it would be quite safe if you were to wire the authorities at Monte Carlo, asking if Mrs. Hillmer is not now at the Hotel du Cercle." The detective started as though he had been shot. "What!" he cried, "you think she is there all the time?" "I think she has been there since Wednesday morning." "That is what I mean. Why did you not tell me sooner?" "Because you never asked me. And now, Mr. White, one word of advice. Go slow." "It's all jolly fine telling me to go slow when I have no reason to go fast. The case even against Corbett is shadowy enough at present." "Exactly. Wait until you can grasp a substance." "I will, sir," said White, jamming his hat on; "but when I lay my hands on Corbett I will grasp him hard enough." It took the policeman all that day to satisfy himself that Mrs. Hillmer had really booked for the Riviera by the Club train from Charing Cross on the preceding Monday. Just as he verified the fact, came a reply from the Monte Carlo police: "Mrs. Hillmer arrived at the Hotel du Cercle on Wednesday. Left for Italy same afternoon. Shall we endeavor to trace her?" "Oh, bother," he growled. "Corbett may be in Jerusalem by this time. And here have I been fussing about Wyoming or some other potato-patch in the Far West."