We both listened for a few moments while the ringing continued, until with sudden resolve I dashed downstairs to ascertain where the bell was. Without difficulty I found it, for there in the hall, revealed by the gas-lamp we had lit, was a telephone instrument with its bell agitated violently. Without a second's delay I placed the receiver to my ear and gave the usual signal-- "Hulloa! Hulloa?" The whirr and clicking stopped, and a voice, squeaky as that of an elderly person, said petulantly-- "I've been ringing up for an hour or more. What's wrong that you haven't replied? You're at fifty-eight, aren't you?" "Yes," I answered, recollecting that fifty-eight was the number of that house. "Nothing is wrong. Why? Can't you be patient?" "I felt uneasy," answered the mysterious voice apologetically. "I thought there might possibly have been some hitch as you haven't rung up." "No," I responded. "None." "Then of course it's all over?" inquired the voice. I started at this strange query. This unknown inquirer was evidently in possession of the truth, and believed himself to be talking to an accomplice. He knew of the commission of the crime, therefore it occurred to me that by the exercise of due caution I might be able to discover his identity. "Yes," I answered, breathless in excitement. "Both?" asked the voice. "Both," I responded. "Good. Then I shall see you at the place we arranged--eh?" "Of course," I answered. "But when? I've forgotten." "Forgotten!" echoed the squeaky voice in a tone of undisguised disgust. "Take care, or you'll blunder yet. You're a confounded idiot. Why, to-morrow at midday." "I know I'm a fool," I replied. "But in the excitement it's quite slipped my memory where you said I was to meet you." Then, holding the receiver tremblingly to my ear, I listened with quick heart-beating for the response of that mysterious, far distant voice which squeaked so strangely, sounding thin and high-pitched, more like that of a woman than of a man. "You're a confounded fool to waste time like this if you're still at fifty-eight," said the voice. "You've said so before," I responded. "But where shall I meet you?" CHAPTER THREE. AN APPOINTMENT. The voice answered at last-- "I'll meet you beside the lake in St. James's Park, Buckingham Palace end, at twelve to-morrow. Remember that." "Very well," I responded eagerly. "Anything more?" "No," was the reply. "Be careful how you get out, and where you go. So long!" Then, next instant, I knew by the sound that the connexion had been switched off. "What's the matter?" asked Patterson, now beside me. "Wait, and I'll tell you afterwards," I said, at the same time ringing up again. In response I was answered by a feminine voice at the Exchange, who inquired what number I desired. "Tell me, miss, who has just been speaking to me. Kindly oblige me, as it's most important."