knew Polly's window
well enough, and dark as it was, she soon found the spot.

It was shuttered, and the shutter was bolted on the inside; but Wyn
scratched upon the blind and after doing so a second time she heard a
movement within.

"Polly!" she breathed.

She did not want to awaken Mr. Jarley. She just felt that she could not
explain to _him_. Of course, what she had hit under the water might
have nothing to do with the sunken boat, and Wyn shrank from disturbing
the boatman himself about it.

"Polly!" she exclaimed, again in a whisper, "it's I--Wyn--Wyn Mallory."

At once she heard her friend's voice in return. The shutter opened.
Polly blinked at Wyn through the darkness.

"My _dear_! What do you want? What has happened?" asked the girl of
the woods.

"Come on out--do, Polly. I've got something to tell you. Just put on
your bathing suit," Wyn whispered.

"For pity's sake! What is it?"

"Don't awaken your father. Come."

"Just a minute," whispered the sleepy Polly, and in not much longer than
the time stated she crept through the window.

"I'd wake father if I went out by the door," she said. "Now come down to
the landing. What are you doing 'way over here at this time o' night?"

"I have the most surprising thing to tell you."

"What about?"

"I wish you'd go over to Gannet Island with me and see if I'm right. The
moon will be up bye and bye; won't it?"

"Yes. But what do you mean? What is the mystery?" inquired Polly. Then
she seized Wyn's arm and demanded that she "Hush!" although Wyn's lips
were not open at the moment.

"I declare I thought I heard something just then," whispered Polly.

"You're bound to hear things in the dark," returned Wyn, cheerfully.

"But it was somebody coughing."

"A bird?" ventured Wyn. "I heard one splashing in the sedges as I came
along in the canoe."

"A bird clearing its throat?" laughed Polly. "Not likely!"

She did not bother about it again, but squeezed Wyn's arm. "Tell me what
the matter is. It must be something very important to bring you 'way
over here alone at night."

"That's right. It is," replied Wyn, and she related to Polly the thing
that was troubling her.

"And, oh, Polly! if that thing I hit under the water should be that
boat----"

"Oh, Wyn! What would father say?"

"He'd be delighted. So would we all. And we must find out for sure."

"I'll tell him in the morning. We'll go there and see----"

But Wyn stopped her. She showed her ho