"In any case, then, if her first exclamation was genuine, she didn't expect to find the man dead."
"No—no—we must remember that. The death was a surprise. Very well. Then Gerald sends Mary up for help. And here's where a little bit of evidence comes in that you picked up and sent along. Do you remember what Mrs. Pettigrew-Robinson said to you in the train?"
"About the door slamming on the landing, do you mean?"
"Yes. Now I'll tell you something that happened to me the other morning. I was burstin' out of the bathroom in my usual breezy way when I caught myself a hell of a whack on that old chest on the landin', and the lid lifted up and shut down, plonk! That gave me an idea, and I thought I'd have a squint inside. I'd got the lid up and was lookin' at some sheets and stuff that were folded up at the bottom, when I heard a sort of gasp, and there was Mary, starin' at me, as white as a ghost. She gave me a turn, by Jove, but nothin' like the turn I'd given her. Well, she wouldn't say anything to me, and got hysterical, and I hauled her back to her room. But I'd seen something on those sheets."
"What?"
"Silver sand."
"Silver—"
"D'you remember those cacti in the greenhouse, and the place where somebody'd put a suit-case or something down?"
"Yes."
"Well, there was a lot of silver sand scattered about—the sort people stick round some kinds of bulbs and things."