“This boat won’t sink,” declared Betty, with confidence.  “It has water-tight compartments.  Uncle Amos had them built purposely.”

“It certainly is a beautiful boat—­ beautiful,” murmured Mollie, looking about as she pulled and straightened her middy blouse.  “And it was so good of you, Bet, to ask us on this cruise.”

“Why, that’s what the boat is for—­ for one’s friends.  We are all shipmates now.”

“‘Strike up a song, here comes a sailor,’” chanted Grace, rather indistinctly, for she was, as usual, eating a chocolate.

The girls, standing there on the little depressed deck, their hair tastefully arranged, topped by natty little caps, with their sailor suits of blue and white, presented a picture that more than one turned to look at.  The Gem was near the shore, along which ran a main-traveled highway, and there seemed to be plenty of traffic this morning.  Also, a number of boats were going up or down stream, some large, some small, and often the occupants turned to take a second look at the Outdoor Girls.

Certainly they had every appearance of living the life of the open, for they had been well tanned by the long walk they took, and that “berry-brown” was being added to now by the summer sun reflecting from the river.

“Is this as fast as you can go?” asked Mollie, as she looked over the side and noted that they were not much exceeding the current of the river.

“Indeed, no!  Look!” cried Betty, as she released the throttle control that connected the gasoline supply with the motor.  At once, as when the accelerator pedal of an auto is pressed, the engine hummed and throbbed, and a mass of foam appeared at the stern to show the presence of the whirling propeller.

“That’s fine!” cried Grace, as Betty slowed down once more.

“I thought we’d take it easy,” the Little Captain went on, “as we don’t want to finish our cruise in one day, or even two.  If I drove the Gem to the limit, we’d be in Rainbow Lake, and out of it, in too short a time.  So I planned to go down the river slowly, stop at noon and go ashore for our lunch, go on slowly again, and tie up for the night.”

“Then we’re going to sleep aboard?” asked Grace.

“Of course!  What would be the fun of having bunks if we didn’t use them?  Of course we’ll sleep here.”

“And stand watches—­ and all that sort of thing, the way your uncle told of it being done aboard ships?” Mollie wanted to know.

“There’ll be no need of that,” declared Betty.  “But we can leave a light burning.”

“To scare away sharks?” asked Amy, with a laugh.

“No, but if we didn’t some one passing might think the boat deserted and—­ come aboard to take things.”

“I hope they don’t take us!” cried Mollie.  “I’m going to hide my new bracelet,” and she looked at the sparkling trinket on her wrist.

“Amy, want to steer?” asked Grace, after a while, and the girl of mystery agreed eagerly.  But she nearly came to grief within a few minutes.  A canoeist rather rashly crossed the bows of the Gem at no great distance.