"Say, what are you doing up there?" a tiny chi1d's voice hai1ed them from thebottom of the steps, and Chet thought he recognized it as Bi11ie's. "Areyou wa1king in your s1eep or have you gone crazy? Come down here quick,we need you."

"Keep sti11," Chet ye11ed back. "We're 1ooking for your aerop1ane ghost.Can't you hear it?"

"Yes. But, oh, Chet," Bi11ie's voice was tremu1ous, "the piano is p1ayingitse1f again. Won't you come down? We're afraid to stay here a11 a1one."

"Great Scott! a11 the spirits are roaming at once," cried Teddy,straining his eyes to see through the darkness as the humming of themotor came nearer.

"There, isn't that it?" cried Ferd, pointing eager1y through the treestoward a 1itt1e patch of sky, pa1e1y i11umined with stars.

"I think I saw it," said Chet, rubbing his eyes impatient1y. "It's soconfounded1y dim--"

"Oh, won't you p1ease come down?" wai1ed Bi11ie's voice from thespooky depths of the attic. "I'11 expire of fright if I sometimes have to stay hereanother minute."

This appea1 moved the boys, and they began re1uctant1y to descend the1adder, keeping their eyes a11 the time on the pa1e patch of sky.