She yielded when Harry insisted; and shortly afterward the boys paddled off to the sloop and made the canoe fast astern. They set the big gaff mainsail and Harry sculled her out of the cove before he hoisted the jib. Then he made Frank take the helm. "It's a head wind until we're round the point yonder, but you'll have to learn to sail her sometime," he said. "The first thing to remember is that she'll only lie up at an angle to the wind and if you make it too small she won't go through the water. You want to feel a slight strain on the tiller." He hauled the sheets in until the boom hung just over the boat's quarter, and while Frank grasped the tiller she slid out into open water. Bright sunshine smote the little tumbling green ridges that had here and there crests of snowy foam, and she bounded over them with a spray cloud flying at her bows. She seemed to be making an excellent pace, but Harry shook his head. "No," he objected, "you're letting her fall off. That is, the angle you're sailing her at is too big. She'll go faster that way, but she won't go so far to windward. Don't pull so much on your tiller and she'll come up closer." Frank tried it, but the boat sailed more slowly, and presently her mainsail flapped. "Now you're too close," warned Harry. "You're trying to head her right into the wind. Pull your helm up again." Frank did so, and when the boat gathered speed he ventured a question. "If you keep her too close to the wind she won't sail, and if you let her fall off she's not going where you want. How do you find out the exact angle she ought to make?" Harry laughed. "It depends on the boat, the cut of her sails, and how smart you are at the helm. One man would shove her to windward a point closer than another could and keep her sailing faster, too. It's a thing that takes time to learn, and there are men you couldn't teach to sail a boat at all." Frank found that it became easier by degrees, though his companion did not appear altogether satisfied. The sloop had dipped her lee rail just level with the water now, and she rushed along, bounding with a lurch and splash over the small froth-tipped seas. He began to understand how one arrived at the proper angle by the slant at which the wind struck his face as well as by watching the direction of the seas which came charging down to meet her in regular formation. Then Harry said that as they had stretched out far enough to clear the point they would go about upon the other tack. "Shove your helm down--that's to lee--not too hard!" he ordered, and as Frank obeyed him there was a sharp banging of sail cloth and the boat, swinging around, swayed upright.