“There’s nothing out of the way in all that. Why did you call him peculiar?” “Well, just his living alone. He doesn’t have much to say to the neighbours, by all accounts. Then he catches insects about the moor and sits up half the night writing about them. They say he’s writing a book.” “What age is he?” “About forty-five, I should say.” “Well, that’s all we can do here. Let’s get on to Tavistock.” French enjoyed the remainder of the drive as much as any he had ever taken. He was immensely impressed by the mournful beauty of the scenery. They passed Two Bridges, presently striking off from the Plymouth road. On the left the great grey buildings of the prison appeared, with rugged North Hessary Tor just beyond and the farm staffed by the prisoners in the foreground. The road led on almost due west until after passing the splendid outlook of Moorshop and descending more break-neck hills they reached cultivated ground and Tavistock. They had driven fast, and less the time they had stopped on the road, the run had taken just sixty-three minutes. The car had behaved excellently, and if French had really been contemplating its purchase he would have been well satisfied with the test. “I want to find out how long the radiator took to cool on that night,” French said. “The point is whether the car would have done any further running, after its trip from here to the place where it was abandoned. If it takes three hours or more to cool, it couldn’t; if less, it might.” “I follow, but I’m afraid that won’t be easy to find out.” “Why not?” “Well, it depends on the weather and specially the wind. I used to drive and I know something about it. If there’s a wind blowing into the radiator it’ll cool about twice as quickly as if the same wind was blowing from behind the car.” “I can understand that,” French admitted. “How was the wind that night?” “A very faint westerly breeze—scarcely noticeable.” “That would be behind the car. Then if we try it to-day in any pretty sheltered place we ought to get, roughly speaking, the same result? The temperature’s about the same to-day as it was that night, I should think?” “That’s so, sir, the weather conditions are as good for a test as you’ll get. But even so, it will be only a rough guide.” “We’ll try it, anyway. Park somewhere and we’ll go and have some lunch.” They left the car in front of the fine old parish church while they lunched and explored the town. Then returning to the car, they sat down to wait. At intervals they felt the radiator, until, just three and a half hours after their arrival, the last sensation of warmth vanished. “That’s three hours and thirty minutes,” Daw declared, “but I don’t think you would be wise to take that too literally. If you say something between three and four hours you won’t be far wrong.” “I agree, Sergeant. That’s all we want. Let’s get home.” That evening French sat down to write up his notes and to consider the facts he had learned.