The girls were as glad to see Betty’s uncle as he was to greet them, and soon, with plenty of supplies on board, and with the old sea captain at the wheel, which Betty graciously asked him to take, the _Gem_ slipped down the river again. At noon, when they tied up to go ashore in a pleasant grove for lunch, Mr. Marlin demonstrated how to tie so many different kinds of knots that the girls said they never could remember half of them. But most particularly he insisted on all of them learning how to tie a boat properly so it could not slip away. Betty already knew this, and Mollie had a fairly good notion of it, but Grace admitted that, all along, she had been making a certain wrong turn which would cause the knot to slip under strain. They motored down the river again, stopping at a small town to enable Mollie to go ashore and telephone home to learn the condition of little Dodo. There was nothing new to report, for the operation would not take place for some time yet. 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.