ispered the brave little Freddie. "It's only the
girls that's hollering."

Then they both put their curls under the bedquilts.

"Someone's playing the piano," Bert said to Harry; and, sure enough, a
nocturnal solo was coming up in queer chunks from the parlor.

"It's a crazy burglar, and he never saw a piano before," Flossie said.

The hall clock just struck midnight. That seemed to make everybody more
frightened.

Uncle Daniel was hurrying down the stairs now.

"There it is again," whispered Bert, as another group of wild chords
came from the piano.

"It must be cats!" exclaimed Uncle Daniel. "Harry, come down here and
help light up, and we'll solve this mystery."

Without a moment's hesitation Bert and Harry were down the stairs and
had the hall light burning as quickly as a good match could be struck.

But there was no more music and no cats about.

"Where is Snoop?" asked Uncle Daniel.

The boys opened the hall door into the cellarway, and found there Snoop
on his cushion and Fluffy on hers.

"It wasn't the cats," they declared.

"What could it be?"

Uncle Daniel even lighted the piano lamp, which gave a strong light,
but there didn't seem to be any disturbance about.

"It certainly was the piano," he said, much puzzled.

"And sounded like a cat serenade," ventured Harry.

"Well, she isn't around here," laughed Uncle Daniel, "and we never
heard of a ghost in Meadow Brook before."

All this time the people upstairs waited anxiously. Flossie held Nan so
tightly about the neck that the elder sister could hardly breathe.
Freddie and Sandy were still under the bedclothes, while Mrs. Bobbsey
and Aunt Sarah listened in the hall.

"Dat sure is a ghost," whispered Dinah to Martha in the hall above.
"Ghosts always lub music," and her funny big eyes rolled around in that
queer way colored people have of expressing themselves.

"Ghosts nothin'," replied Martha indignantly. "I dusted every key of
the piano to-day, and I guess I could smell a ghost about as quick as
anybody."

"Well, I don't see that we can do any good by sitting around here,"
remarked Uncle Dan to the boys, after the lapse of some minutes. "We
may as well put out the lights and get into bed again."

"But I cannot see what it could be!" Mrs. Bobbsey insisted, as they all
prepared to retire again.

"Neither can we!" agreed Uncle Daniel. "Maybe our piano has one of
those self-playing tricks, and somebody wound it up by accident."

But