It was evident that the sudden reaction of having nothing to do, after his unremitting labours of the past six months, was having an unfavourable effect upon Dr. Priestley’s temper. He roamed about the study, pulling out a file from time to time, and finding fault with Harold because some item did not come immediately to his hand. It was not until it was time to dress for dinner that he desisted from this irritating occupation. And even at dinner he was silent and morose, obviously seeking in vain for some new interest which should occupy his restless thoughts. But hardly had he and Harold finished their coffee, which they always had in the study after dinner, than Mary the parlourmaid opened the door softly. “Inspector Hanslet to see you, sir,” she announced.

The Professor turned so abruptly in his chair as seriously to endanger the coffee cup he was holding. “Inspector Hanslet!” he exclaimed. “Why show him in, of course. Good evening, Inspector, it was only this morning that Harold and I were speaking of you. I hope that you enjoyed yourself in America.”