“Why sir,” said Miller, “there is a coat. In the pockets were a pair of gloves, a muffler, a box of matches, a tram-ticket and a Yale key. Mrs. Chater would like to know whose coat it is.” He untied the parcel with his eye cocked at our rather disconcerted client, and Thorndyke watched him with a faint Smile.

“This is very kind of you, Miller,” said he, “but I think a clairvoyant would be more to your purpose.”

The superintendent instantly dropped his facetious manner.

“Seriously, sir,” he said, “I should be glad if you would take a look at the coat. We have absolutely nothing to go on, and yet we don’t want to give up the case. I have gone through it most thoroughly and can’t find any clue to guide us. Now I know that nothing escapes you, and perhaps you might notice something that I have overlooked; something that would give us a hint where to start on our inquiry. Couldn’t you turn the microscope on it, for instance?” he added, with a deprecating smile.

Thorndyke reflected, with an inquisitive eye on the coat. I saw that the problem was not without its attractions to him; and when the lady seconded Miller’s request with persuasive eagerness, the inevitable consequence followed.

“Very well,” he said. “Leave the coat with me for an hour or so and I will look it over. I am afraid there is not the remotest chance of our learning anything from it, but even so, the examination will have done no harm. Come back at two o’clock; I shall be ready to report my failure by then.”

He bowed our visitors out and, returning to the table, looked down with a quizzical smile on the coat and the large official envelope containing articles from the pockets.

“And what does my learned brother suggest?” he asked, looking up at me.

“I should look at the tram-ticket first,” I replied, “and then—well, Miller’s suggestion wasn’t such a bad one; to explore the surface with the microscope.”

“I think we will take the latter measure first,” said he. “The tram-ticket might create a misleading bias. A man may take a tram anywhere, whereas the indoor dust on a man’s coat appertains mostly to a definite locality.”