There's no sign of anybody." "They haven't found--Mr.Anderson ?" Dale shook her head.

"Not yet." She turned toward her aunt.

Miss Cornelia had begun to enjoy herself once more.
Rapping on the mantelpiece, poking and pressing various corners and sections of the mantel itself, she remembered all the detective stories she had ever read and thought, with a sniff of scorn, that she could better them.

There were always sliding panels and hidden drawers in detective stories and the detective discovered them by rapping just as she was doing, and listening for a hollow sound in answer.

She rapped on the wall above the mantel--exactly--there was the hollow echo she wanted.
"Hollow as Lizzie's head!" she said triumphantly.