“How did you come to think of that, sir? I didn't mention it to you.”
“It was just a long shot, Inspector. As soon as Silverdale stated that he had been working all that night at the Croft-Thornton, I was pretty sure he was lying. So were you, I guessed. Then you walked across to the window and looked down. As I was wondering myself whether the window was visible from the street, it didn't take much mind-reading to see what you were driving at. And from your questions to Markfield later on, I couldn't help inferring that you had the constable on the beat at the back of your thoughts. Obviously you meant to check Silverdale's story by asking the constable on duty if he'd noticed a light in Silverdale's room that night. There was no light, of course?”
“No, sir. There wasn't a light anywhere in the building, that night. I made the constable look up his notebook.”
“Then you've caught Master Silverdale in a very bad lie. By the way, I suppose you noticed that girl who came into his room while we were talking to him: the Miss Deepcar who dined with him down town that night. What did you make of her?”
“Pretty girl, sir, very pretty indeed. The quiet sort, I'd judge. One of the kind that a man might do a good deal to get hold of, if he was keen on her.”
Sir Clinton's expression showed that he did not disagree with the Inspector's summing up.
“By the way,” he continued, “did you take any note of what she said to Silverdale at that time?”
“Not particularly, sir. It was all Greek to me—too technical.”
“It interested me, though,” Sir Clinton confessed. “I've a chemical friend—the London man who's going to act as a check on Markfield for us in the search for the poison, as a matter of fact—and he talks to me occasionally about chemistry. You don't know what a ‘mixed melting-point’ is, I suppose?”
“No, sir. It sounds confused,” said the Inspector mischievously.