Palmer was easily appeased, and very soon, on their former footing, they were talking together, Palmer describing to the doctor a method of reading cyphers of the simpler kind, in which letters are replaced by arbitrary signs. There was, in the lucidity of his exposition, something which gave his companion a pleasure that was almost æsthetic. The exhibition of this fresh young intelligence at work was to him extremely fascinating, and the difficulty he experienced in getting at any conception of the temperament behind it added to his interest. “Aren’t you very good at mathematics?” he asked. “Fairly good. Not good enough to specialize――at least, I don’t want to specialize. There are three or four chaps at school who are probably just as good as I am; and of course they work a great deal harder.” But darkness had crept up while they were talking, and Palmer signified that they might now proceed with what they had to do. “If he is in, there will be a light in his window: if there isn’t a light, we can call. I don’t fancy he is a person who sits much in the dark when he is alone.” They walked up the street in the direction of the house where Mr. Bradley lodged. This house stood on the extreme outskirts of the town; nevertheless, it did not take them many minutes to reach it. They had chosen the farther side of the road, so that they could see from some distance whether there was a light in the window or not. There was none, and they were about to cross over when Palmer suddenly pulled his companion back into the shadow of a gateway. Simultaneously, the door of Mr. Bradley’s house opened, and the organist himself came out. They watched him walk on down the street. “That was a close shave,” Palmer murmured. “I think we’d better wait for ten minutes, just to see if he turns up again. He may only have gone to the post or something, and it will take him about ten minutes to go there and back. If I had been alone I would have followed him till I was sure of not being interrupted. You see, he hasn’t taken the direction of the church.” “Oh, he’ll not come back,” said the doctor, optimistically, as they strolled on. “The shops are closed: he has gone for a walk.” “He may have. He had his stick with him, and he would hardly have taken that if he had only been going to the post. Besides, he hadn’t a letter, unless it was in his pocket. Still, I fancy it would be better to give him a quarter of an hour.” The doctor, however, was impatient, and in the end Palmer allowed himself to be persuaded. They retraced their steps and knocked at the door. Mr. Bradley’s landlady informed them that the organist was out, but could give no information as to when he would return. “Perhaps we could wait for a few minutes?” the doctor suggested. “Certainly, Doctor O’Neill. I’m sure he’d be sorry if he thought he had missed you.”