“Ah, that is part of the case that I haven’t had an opportunity of going into with you yet, Charles. Won’t you sit down. The fact is, I have been rather expecting some approach of this kind. Dr. Cassilis and I have ascertained that Weathered induced some of his patients to write him letters of a rather compromising kind. The arrangement was that the letters should be signed with a number instead of a name, probably they bore no address. The object of this advertisement is to find out who the writers are. The demand for money will come later.” “Blackmail!” the Inspector gasped in horror. “I’m afraid so. An honest person who had found such a correspondence would have burnt it. You see now one of my reasons for not dropping the case to oblige that Crown Prince of Slavonia.” One of the reasons only. I had little doubt as to another. Captain Charles looked extremely subdued. “I had no idea of anything like this in the background, I needn’t say, Sir Frank. I will look up these solicitors at once. Chancery Lane--there are better addresses than that, and there are worse. Unless you have anything else to advise.” “I should advise you to find out what you can about the solicitors, certainly. But I doubt if they are in possession of the letters. I shouldn’t be surprised if the letters were in Paris by this time.” Captain Charles struck his forehead. “Of course! The widow has carried them abroad to be out of reach in case of trouble. It was fortunate that we heard of their flight so soon. We know where they are already. They have some smart men in the Rue Jerusalem.” “I shall be glad if you will write me a line of introduction to the French police,” Tarleton responded. “By the way, have you secured me that finger-print yet?” “I have it here, Sir Frank.” The Inspector took out a substantial pocket-book and extracted a mounted photograph, which my chief slipped into his own pocket without giving it a glance. Charles looked as if he were as much in the dark as I was as to the meaning of this proceeding. “It may come in useful,” was all the consultant said. “But you were going to tell us where Mrs. Weathered and her daughter were hiding.” “They don’t seem to be hiding, that’s the curious part of it. Perhaps they don’t understand the law about extradition. They’ve put up at a respectable hotel on Cook’s list, a hotel swarming with English tourists, the Hotel St. Catherine in the Rue Tivoli.” Tarleton knitted his brows at this intelligence. “We don’t know yet the reason for their flight, if it is a flight,” he observed thoughtfully. “We have nothing against either of them so far, remember.” He drew out his mascot and played with it gently for a minute while Charles and I watched him in keen suspense. Suddenly he looked up and spoke to the Inspector in a brisk voice.