“Well,” he said, “you see we are just harmless naturalists. By the way, what did you think we were looking for?” “Never mind what I thought,” the other replied fiercely. “This is private land. You have no business here, and you have got to clear out.” “Very well,” said Thorndyke. “As you please. There are plenty of other ditches.” He took the vasculum and the case of bottles, and having put them in his pocket, unscrewed his net, wished the stranger “Good morning,” and turned back towards the station. The man stood watching us until we were near the level crossing, when he, too, turned back and retired to the factory. “I saw you take something out of the net,” said I. “What was it?” He glanced back to make sure that the manager was out of sight. Then he put his hand in his pocket, drew it out closed, and suddenly opened it. In his palm lay a small gold dental plate with four teeth on it. “My word!” I exclaimed; “this clenches the matter with a vengeance. That is certainly Cyrus Pedley’s plate. It corresponds exactly to the description.” “Yes,” he replied, “it is practically a certainty. Of course, it will have to be identified by the dentist who made it. But it is a foregone conclusion.” I reflected as we walked towards the station on the singular sureness with which Thorndyke had followed what was to me an invisible trail. Presently I said: “What is puzzling me is how you got your start in this case. What gave you the first hint that it was homicide and not suicide or misadventure?” “It was the old story, Jervis,” he replied; “just a matter of observing and remembering apparently trivial details. Here, by the way, is a case in point.” He stopped and looked down at a set of tracks in the soft, earth road--apparently those of the van which we had seen cross the line. I followed the direction of his glance and saw the clear impression of a Blakey’s protector, preceded by that of a gash in the tyre and followed by that of a projecting lump. “But this is astounding!” I exclaimed. “It is almost certainly the same track that we saw in Ponder’s Road.” “Yes,” he agreed. “I noticed it as we came along.” He brought out his spring-tape and note-book, and handing the latter to me, stooped and measured the distances between the three impressions. I wrote them down as he called them out, and then we compared them with the note made in Ponder’s Road. The measurements were identical, as were the relative positions of the impressions.