“Yes,” went on Violet accusingly, “and it was you who said you’d be disappointed if you didn’t see a ghost or two.”

Laura groaned.

“What’s the use of holding things up against me that I said when I was young and foolish?” she asked.  “Anyway, I didn’t think we would really see anything.”

“Well, we haven’t,” said Billie.  “All we’ve done is to hear things—­”

“But we’ve heard plenty,” sighed Violet.  “There!  What’s that?”

The girls listened, feeling almost ready to scream, but could hear nothing but the sighing of the wind in the tree tops.

“Only the wind, silly,” said Laura, then added with an almost comfortable feeling at the thought:  “Mrs. Gilligan’s on guard anyway.”

“Yes,” said Violet, adding with a sigh that seemed to come from her very toes:  “I only hope the piano doesn’t swallow her up before morning.  I’ve come to expect almost anything!”

CHAPTER XX

THE MOTOR AGAIN

The piano did not swallow Mrs. Gilligan up, and, as a matter of fact, the good woman did not stand guard until morning.  Half an hour of sitting alone in that gloomy room watching a piano that had played itself was enough to ruin even her seasoned nerves.

Once back in her room she scolded herself for being such an idiot, laughed at her fears, and, being a normal, healthy woman, fell almost instantly to sleep.

In the morning the girls themselves felt somewhat inclined to laugh at the fright they had had, and yet they knew that what had happened had been no figment of their imaginations.  The sound, though weird and eerie, had been real—­even Mrs. Gilligan would testify to that.

“Well, I tell you what we ought to do,” said Ferd, as he sat down to a huge plateful of breakfast.  “We fellows ought to take turn and turn about keeping watch.  There must be some reason for the noise the girls heard, and I won’t be happy until we find out what it was.”

“I think you have the right idea,” replied Chet, decidedly.  “The only condition I make is that I be allowed to stand the first watch.”

“You’ll do nothing of the kind, any of you,” broke in Mrs. Gilligan, with that slight tightening of her upper lip that the girls and boys had come to know—­and respect.  “That’s a fine way to see all sorts of things that ain’t and hear all sorts of things that never happened.  Sit up in the dark, waiting for something to happen!  I guess not!”

“But we can’t just sit back and let the piano perform like that every night, can we?” asked Ferd, in an argumentative tone.  “I’d rather stay awake part of the night than all of it.”

“Don’t you even want to solve the mystery?” asked Chet, in an aggrieved voice.

“Mystery—­humph,” grunted Mrs. Gilligan, feeling very brave and disdainful in the bright sunshine.  “I don’t believe there’s a bit of mystery in the whole thing.”