imagination, like fortune-telling and Ouija boards, don't y' know; but—my word!—it desolates me to think that you, old chap, would give credence to such mystical moonshine."
"Don't let it spoil your entire day," said Markham acridly.
"Regard the unsolved, or successful, crimes that are taking place every day," Vance continued, disregarding the other's irony, "—crimes which completely baffle the best detectives in the business, what? The fact is, the only crimes that are ever solved are those planned by stupid people. That's why, whenever a man of even mod'rate sagacity decides to commit a crime, he accomplishes it with but little diff'culty, and fortified with the pos'tive assurance of his immunity to discovery."
"Undetected crimes," scornfully submitted Markham, "result, in the main, from official bad luck—not from superior criminal cleverness."
"Bad luck"—Vance's voice was almost dulcet—"is merely a defensive and self-consoling synonym for inefficiency. A man with ingenuity and brains is not harassed by bad luck. . . . No, Markham old dear; unsolved crimes are simply crimes which have been intelligently planned and executed. And, d' ye see, it happens that the Benson murder falls into that categ'ry. Therefore, when, after a few hours' investigation, you say you're pretty sure who committed it, you must pardon me if I take issue with you."
He paused and took a few meditative puffs on his cigarette.
"The factitious and casuistic methods of deduc-
