Nervously the girls followed them in, throwing the light of the candles on the old piano, but, as far as they could see, nothing had been disturbed.

The ancient instrument stood as dignified and aloof as ever, and in the whole room not a chair was out of place.

“Nothing here,” said Chet, looking disappointed.  “Say, the girls promised us a regular show, fellows, and they haven’t come across.”

“What shall we do to ’em?” asked Teddy, looking almost equally disappointed.

“But we heard it,” said Billie, shivering with excitement.

“It was just as if somebody had taken the back of his finger,” Laura added, “and run it all the way down the keyboard from the top note of the treble to the last note of the bass.”

“Oh, you must have been dreaming,” said Ferd, opening the piano to examine it inside.

“No, they weren’t dreaming,” said Mrs. Gilligan seriously.  “Because I was very much awake when I heard it.”

“You heard it, too?” asked Chet, beginning to be interested again.

“I certainly did,” said Mrs. Gilligan, with a grimness that left no room for doubt.  “And I’m not given to imagining things, either.”

“Well, I move we look around a bit,” suggested Ferd, who was always eager for action.  “The ghost may have retreated to the dining-room or something—­”

“No, siree!” said Violet decidedly.  “If the rest of you want to go roaming all over this gloomy old place at night you can do it, but you’ll have to leave me out.”

“Vi’s right,” said Mrs. Gilligan, just as the boys were about to protest.  “There isn’t any use going into this thing any further to-night and getting the girls all upset.  I’ll stay down here awhile and see what I can see.”

“Let me stay with you,” asked Chet eagerly.

“And me.”

“And me.”

Ferd and Teddy spoke almost in the same breath.

“No, I want you all to go up and get into bed,” said Mrs. Gilligan decidedly.  “If I see anything,” she added, with a grim smile, “anything that looks like a ghost that is, I’ll call you.”

“That’s a promise,” said Chet, looking back over his shoulder as he reluctantly followed the others upstairs.  “Because if I should miss getting a look at that ghost, I’d be disappointed for life.”

“Well, I’ve had enough of spooks to last me forever,” said Laura, with a shivery glance over her shoulder as the boys left the girls at their door and started off down the hall.  “If that piano begins to play itself again to-night, I’ll just die, that’s all there is to it.”

The girls crept into bed, careful to leave their candles burning.

“You know, Billie,” said Violet in an awed little voice, “this thing is really getting serious.”

“I should say so,” agreed Laura, drawing the bed clothes a little tighter about her.

“Well, it isn’t my fault, is it?” asked Billie.  “I didn’t ask Aunt Beatrice to leave me a haunted house.  And, anyway,” she added very truthfully, “it was you, Laura, who first suggested coming here.”