"Nothing," she answered. "They came about six months ago, a young lady and a very old gentleman, with a single maid-servant. They speak to no one, and, as far as I have observed, have very few friends. I have often remarked to my son, who is a civil engineer, and now away making the railway in China, that they are a mysterious couple. What is wrong with them?" "Oh, it's simply a private matter," my companion answered carelessly, not wishing to alarm the neighbourhood by news of our discovery. "What is the old gentleman like? Can you describe him?" I inquired. No doubt she took me for a detective, but at that moment this thought did not occur to me. "He is sixty, I should think, old and decrepit, with white hair, and always walks with a stick." "And the lady was his daughter?" suggested the inspector. "I suppose her to be his daughter," she answered. "The old man's name is Dawson, I believe--at least one day a messenger-boy brought a note here by mistake, addressed to Professor Dawson. The daughter is a very good pianist, and plays every morning regularly." "They are well off, as far as you can judge?" Patterson inquired with his assumed careless air. "No, I don't think they are, because my maid heard at Boucher's--the grocer's across the way--that they owed a large bill which they couldn't settle. Again, people who have a house of that sort do not have coal by the hundredweight taken down into the kitchen as they do." Patterson nodded. No more sure sign of a light purse is there than the purchase of coal by the half-sack. Yet the interior of that house, with its well-laid dinner-table, certainly did not betray any sign of poverty. Indeed, I had noticed in the cellar a dusty stock of choice wines, hocks, ports, and champagnes of expensive brands. "You don't know the young lady's name, then?" asked my friend, after a slight pause. "If she's really his daughter it would, I suppose, be Dawson," she replied with a smile. "But I'm not certain, remember, as to either of their names." "Perhaps your servants may know something about them. Servants generally gossip and pick up information about one's neighbours, you know." "You are right," answered the affable old lady, "they gossip far too much. Unfortunately, however, both my servants are out at this moment." We chatted on, but it was evident from her conversation that her servants knew little beyond what she did. One statement she made was somewhat curious. She alleged that a few nights before she was awakened about two o'clock in the morning by hearing the loud shrill screams of a woman who seemed to be in the room next hers in the adjoining house. She could hear a man's voice talking low and gruffly, and three or four times were the screams repeated, as if the woman were in excruciating pain. "What visitors came to the house?" Patterson asked at length. "Very few. A youngish gentleman came sometimes. He called the other morning just as I was going out."