Grace also called up to ask if anything had been heard of the missing horse and papers, but there was no good news.  However, there was no bad news, Will, who talked to his sister, reporting that the interests opposed to their father had made no move to take advantage of the non-production of the documents.

“Have a good time, Sis,” called Will over the wire.  “Don’t worry.  It doesn’t do any good, and it will spoil your cruise.  Something may turn up any time.  But it sure is queer how Prince can be away so long.”

“It certainly is,” agreed Grace.

“And so you expect to make Rainbow Lake by six bells?” asked Betty’s uncle, as he paced up and down the rather restricted quarters of the deck.

“Yes, Uncle, by seven o’clock,” answered Betty, who was at the wheel.  “Six bells—­ six bells!” he exclaimed.  “You must talk sea lingo on a boat, Bet.”

“All right, Uncle—­ six bells.”

“Where’s your charts?” he asked, suddenly.

“Charts?”

“Yes, how are you sailing?  Have you marked the course since last night and posted it?  Where are your charts—­ your maps?  How do you expect to make Rainbow Lake without some kind of charts?  Are you going by dead reckoning?”

“Why, Uncle, all we have to do is to keep right on down the river, and it opens into Rainbow Lake.  The lake is really a wide part of the river, you know.  We don’t need any charts.”

“Don’t need any charts?  Have you heaved the lead to see how much water you’ve got?”

“Why, no,” and she looked at him wonderingly.

“Well, well!” he exclaimed.  “Oh, I forgot this isn’t salt water.  Well, I dare say you will stumble into the lake after some fashion—­ but it isn’t seaman-like—­ it isn’t seaman-like,” and the old tar shook his grizzled head gloomily.

Betty smiled, and shifted her course a little to give a wide berth to some boys who were fishing.  She did not want the propeller’s wash to disturb them.  They waved gratefully to her.

The sun was declining in the west, amid a bank of golden, olive and purple clouds, and a little breeze ruffled the water of the river.  The stream was widening out now, and Betty remarked: 

“We’ll soon be in the lake now.”

“The boat—­ not us, I hope,” murmured Grace.

“Of course,” assented Betty, “Won’t you stay with us to-night, Uncle Amos?” she asked, as she opened the throttle a little wider, to get more speed.  “You can have one of the rear—­ I mean after, bunks,” she corrected, quickly.

“That’s better,” and he smiled.  “No, I’ll berth ashore, I guess.  I’ve got to get back to town, anyhow.  I just wanted to see how you girls were getting along.”

The Gem was speeding up.  They rounded a turn, and then the girls exclaimed: 

“Rainbow Lake!”

In all its beauty this wide sheet of water lay before them.  It was dotted with many pleasure craft, for vacation life was pulsing and throbbing in its summer heydey now.  As the Gem came out on the broad expanse a natty little motor boat, long and slender, evidently built for speed, came racing straight toward the craft of the girls.