but I never heard of one who
insisted upon playing the piano in the dead of night."

"He must have been a musician in his life time," suggested Chet. "That's
the reason he comes and haunts the piano."

"Well, I don't see why he doesn't choose a regular piano to haunt,"
said Billie, feeling irritable because she was very sleepy and had been
very much frightened. "It's bad enough for a live person to play, let
alone a ghost."

"And where could it have gone?" wondered Laura, her eyes big and dark
with excitement. "The minute we heard the noise--I guess we're sort of
listening for it even in our sleep--we jumped up and came down here while
Billie went to call you boys. It was playing almost up to the minute we
came into the room."

"And maybe we weren't afraid to go in!" said Violet, with a shudder. "I
don't know how we ever got the courage."

"Well, you only came because Mrs. Gilligan and I went ahead with the
broom and the poker," sniffed Laura.

"Was it playing when you came down the stairs?" asked Chet, interested.
"And did it stop as soon as you entered the room?"

"Yes," it was Mrs. Gilligan who answered this time. "And it was good for
him he did. I've lost enough sleep through the miserable rascal and I was
just ripe for a tussle."

"I don't blame him for running," said Teddy, with a chuckle.

"But where did he go?" asked Laura again. "We were sure that we'd see
something--goodness knows what--when we turned the corner of the room."

"And all we saw was a--a large amount of nothing at all," added Violet,
wide-eyed.

"Perhaps," suggested Ferd, with a chuckle, "the aeroplane we heard
belonged to him--"

"A ghost's aeroplane," murmured Billie, smothering another
hysterical chuckle.

"And when you girls came in he just soared skyward and went off in it."

"It's funny we never thought of that," said Teddy scornfully.

"Well, I wish we could find out what it is," sighed Billie, as they
started upstairs again. "This staying awake all night isn't very
much fun."

"But isn't it strange," asked Laura, stopping on the landing and looking
back at them, "that both the piano and the motor should start again on
the same night?"

"Yes, it is, rather," said Chet, adding seriously: "I wonder if there
could really be any connection between the two."

"There's no use wondering, that I can see," said Mrs. Gilligan, preparing
to send them off to their respective bedrooms. "I think the best thing we
can do is not t