The setting of this sail struck Frank as an immensely complicated business. He watched Priscilla working with a whole series of ropes and admired her skill greatly, until it occurred to him that she was not very sure of what she was doing. A rope, which she had made fast with some care close beside him, had to be cast loose, carried forward, passed outside a stay, and then made fast again. There appeared to be three corners to the spinnaker, and all three were hooked turn about on the end of the boom. Even when the third was unhooked again and the one which had been tried first restored to its place Priscilla seemed a little dissatisfied with the result. Another of the three corners was caught and held by the clip-hooks on the end of the halliard. Priscilla moused these carefully, explaining why she did so, and then found that she had to cut the mousing and catch the remaining corner of the sail with the hooks. When at last she triumphantly hoisted it the thing went up in a kind of bundle. Its own sheet was wrapped round it twice, and a jib sheet which had somehow wandered away from its proper place got twined round and round the boom which remained immovable near the mast. Priscilla surveyed the result of her work with a puzzled frown. Then she lowered the sail and turned to Frank. “I thoroughly understand spinnakers,” she said, “in theory. I don’t suppose that there’s a single thing known about them that I don’t know. But they’re beastly confusing things when you come to deal with them in practical life. Lots of other things are like that. It’s exactly the same with algebra. I expect I’ve told you that I simply loathe algebra. Well, that’s the reason. I understand it all right, but when it comes to doing it, it comes out just like that spinnaker. However it doesn’t really matter. That’s the great comfort about most things. You get on quite well enough without them, though of course you would get on better with, if you could do them.” The Tortoise did in fact slip along at a very satisfactory pace in spite of the lightness of the wind. It was just half past eight when they reached the mouth of the bay in which they had lunched the day before with Miss Rutherford. “I feel rather,” said Priscilla, “as if I could do with a little breakfast There’s no use going on shore. Let’s anchor and eat what we want in the boat.” Frank who was very hungry agreed at once. He rounded the boat up into the wind and Priscilla flung the anchor overboard. Then she picked her parcels one by one from the folds of the spinnaker in which they had wrapped themselves. “It won’t do,” she said, “to eat everything today at the first go off the way we did yesterday. Specially as we’ve promised to give Miss Rutherford luncheon. The duck, for instance, had better be kept.” She laid the duck down again and covered it, a little regretfully, with the spinnaker. She took up the jampot which contained the caramel pudding. Her face brightened as she looked at it.