“You are quite sure that this was the path he followed?” he asked. “I can’t see any tracks along it at all, either of your feet or of the bicycle.” “Perfectly certain,” replied the Professor stiffly. “I am not likely to mistake it, especially as it would appear to be the only path in the vicinity.” Hanslet nodded, and made his way through the tangled vegetation towards the ruins of the cottage. He walked carefully round the mound, then proceeded to the broken walls of the laboratory. He gazed at these for a minute or two, then turned towards his companions, who had remained on the path. “I wish you would come here a minute, will you, Mr. Merefield?” he called. Harold obeyed his summons, and Hanslet led him round an angle of the walls, out of sight of the Professor. “Has he been overdoing it a bit lately?” he asked in a low tone. “Overworking himself, or anything like that, I mean? I thought he looked pretty well done up when I first saw him the other evening.” “Well, he’s hardly been outside the house for the last six months,” replied Harold. “He’s been busy with a new book, and I think it took it out of him a good deal. Why?” “You heard that extraordinary yarn he spun us just now, about the Black Sailor and his bicycle. If the tracks showed anywhere, it would be on that path. Now here, all round this place, you can see the Professor’s footmarks. He was here all right last night, as he says. But it’s odd we can’t find traces of the other fellow. You don’t think he can have dreamt it, do you?” “It would be most unlike him,” replied Harold. “Why should he imagine such a thing, anyhow?” “Well, you see, if this jury business is correct, he is the only survivor. You remember his telling us the other day in town that there would be one more murder? He meant that his own life was threatened, and I expect it’s been preying on his mind. It’s the only way I can account for this business.” Harold shook his head. “It is true that he hasn’t been quite himself lately,” he replied. “But I don’t think he’s got to the stage of seeing things. Anyhow, how do you account for the counter he gave you just now?” “How do you account for anything in this blessed case?” retorted Hanslet. “I believe the devil’s at the bottom of it, if you ask me. I wish you would follow up that path in the opposite direction for a bit, while I poke about here. If you find the marks of a bicycle wheel, don’t touch ’em, but come back and tell me.” Harold followed the path for half a mile or so in the direction of the Studland road, and returned shaking his head. Hanslet had by this time finished his inspection of the ruins. He turned to the Professor, who had joined him. “Well, there’s nothing very definite to be seen here,” he said, with his usual cheerful smile. “What do you suggest we do next, Professor?” “Return to the inn for dinner,” replied Dr. Priestley. “To-morrow, if you agree, I propose to return to London by an early train.”