“Exactly!” chortled Miss Ickthorpe. “And what happens? I know, because I’m a very observant person and, besides, Old Icky shaves every morning and I can’t help noticing when he kisses me good-morning. Applied with the fingers on cheeks still slightly moist, the powder goes on in streaks, smudgy, heavier in some spots than others. But look at my face!” They looked, with varying expressions of appreciation. “You don’t see powder streaks on my face, do you? Of course not! And why? Because I’m a woman, and a woman uses a powder-puff, and there isn’t a single powder-puff in Spargo’s bedroom or bathroom!”

Ellery smiled—almost with relief. “Then you suggest, Miss Ickthorpe, that the last person with Spargo, presumably his murderess, was a woman who watched him shave and then, with endearment perhaps, took out her own powder-puff and dabbed it over his face—only to bash him over the head with the stone hammer a few minutes later?”

“Well—yes, although I didn’t think of it that way. . . . But—yes! And psychology points to the specific woman, too, Mr. Queen. A man’s wife would never think of such an—an amorous proceeding. But a man’s mistress would, and I say that Spargo’s lady-love, Jane Terrill, whom I visited only an hour ago and who denies having powdered Spargo’s face—she would!—killed him.”

Ellery sighed. He rose and twitched his cigarette-stub into the fireplace. They were watching him, and each other, with expectancy. “Aside,” he began, “from complimenting you, Miss Ickthorpe, on the acuteness of your knowledge of mistresses”—she uttered an outraged little gasp—“I want to say this before going ahead. The three of you have proved very ingenious, very alert; I’m more pleased than I can say. I do think we’re going to have a cracking good class. Good work, all of you!”

“But, Mr. Queen,” protested Burrows, “which one of us is right? Each one of us has given a different solution.”

Ellery waved his hand. “Right? A detail, theoretically. The point is you’ve done splendid work—sharp observation, a rudimentary but promising linking of cause and effect. As for the case itself, I regret to say—you’re all wrong!”

Miss Ickthorpe clenched her tiny fist. “I knew you’d say that! I think you’re horrid. And I still think I’m right.”

“There, gentlemen, is an extraordinary example of feminine psychology,” grinned Ellery. “Now attend, all of you.

“You’re all wrong for the simple reason that each of you has taken just one line of attack, one clue, one chain of reasoning, and completely ignored the other elements of the problem. You, John, say it’s Spargo’s wife, merely because her photograph-album contains a picture from which a circular patch with two heads has been cut away. That this might have been sheer coincidence apparently never occurred to you.