They went back to the boat, and the lanterns were lighted.

“Oh, doesn’t it look too nice to sleep in!” exclaimed Amy, as they gazed into the little cabin, with its tastefully arranged berths.

“I’m tired enough to sleep on almost any thing,” yawned Mollie.  “Let’s see who’ll be the first to——­ "

“Not snore, I hope!” exclaimed Betty.

“Don’t suggest such a thing,” came from Amy.  “We are none of us addicted to the luxury.”

But, after all, tired as they were, no one felt like going to sleep, once they were prepared for it.  They talked over the events of the day, got to laughing, and from laughing to almost hysterical giggling.  But finally nature asserted herself, and all was quiet aboard the Gem, which had been moored to a private dock, just above the town.

It was Betty, rather a light sleeper, who awoke first, and she could not account at once for the peculiar motion.  It was as though she was swinging in a hammock.  She sat up, and peered about the dimly lighted cabin.  Then the remembrance of where she was came to her.

“But—­ but!” she exclaimed.  “We’re adrift!  We’re floating down the river!”

She sprang from her berth and awakened Grace by shaking her.

CHAPTER XI

 In danger

“What is it?  Oh, what has happened?”

Grace cried half hysterically as she saw Betty bending over her.  The others awakened.

“Why, we’re moving!” exclaimed Amy, in wonderment.

“What did you want to start off for, in the middle of the night?” Mollie asked, blinking the sleep from her eyes.

“I didn’t,” answered Betty quickly.  “We’re adrift!  I don’t know how it could have happened.  You girls tied the boat, didn’t you?”

“Of course,” answered Grace.  “I fastened both ropes myself.”

“Never mind about that,” broke in Aunt Kate.  “I don’t know much about boats, but if this one isn’t being steered we may run into something.”

“That’s so!” cried Betty.  “But I didn’t want to go out on deck alone—­ slip your raincoats on, girls, and come with me!  There may be—­ I mean some one may have set us adrift purposely!”

“Oh, don’t say such things!” pleaded Grace, looking at the cabin ports as though a face might be peering in.

Quickly Betty and Mollie got into their long, dark coats, and without waiting for slippers reached the after deck.  As they looked ahead they saw a bright light bearing directly for them.  It was a white light, and on either side showed a gleam of red and green.  Then a whistle blew.

“Oh, we’re going to be run down!” cried Mollie.  “A steamer is coming directly for us, Betty!”

“We won’t be run down if we can get out of the way!” exclaimed Betty, sharply.  “Push that button—­ the automatic, I mean—­ and start the motor.  I’ll steer,” and Betty grasped the wheel with one hand, while with the other she pulled the signal cord, sending out a sharp blast that indicated her direction to the oncoming steamer would be to port.  The steamer replied, indicating that she would take the same course.  Evidently there was some misunderstanding.