Frank felt confident that he was stronger in the arms than Priscilla. He crept forward and put his whole strength into a pull on the anchor rope. The Tortoise twisted herself broadside on to the breeze and then listed over to windward. Priscilla looked round her in amazement. The breeze was certainly very light, but it was contrary to her whole experience that a boat with sails set should heel over towards the wind. She told Frank to stop pulling. The Tortoise slowly righted herself and then drifted back to her natural position, head to wind. “The only thing I can think of,” said Priscilla, “is that the anchor rope has got round the centreboard. It might. You never can tell exactly what an anchor rope will do. However, if it has, we’ve nothing to do but haul up the centreboard and clear it.” She took the centreboard rope and pulled. Frank joined her and they both pulled. The centreboard remained immovable. The Tortoise was entirely unaffected by their pulling. “Jammed,” said Priscilla. “I feel a jolly sight less like that dove than I did. It looks rather as if we were going to spend the day here. I don’t want to cut the rope and lose the anchor if I can possibly help it, but of course it may come to that in the end, though even then I’m not sure that we’ll get clear.” “Can we do nothing?” said Frank. “This,” said Priscilla, “is a case for prolonged and cool-headed reasoning. You reason your best and I’ll bring all the resources of my mind to bear on the problem!” She sat down in the bottom of the boat and gazed thoughtfully at the stone perch. Frank, to whom the nature of the problem was obscure, also gazed at the stone perch, but without much hope of finding inspiration. Priscilla looked round suddenly. “We might try poking at it with the blade of an oar,” she said. “I don’t think it will be much use, but there’s no harm trying.” The poking was a total failure, and Priscilla, reaching far out to thrust the oar well under the keel of the boat, very nearly fell overboard. Frank caught her by the skirt at the last moment and hauled her back. “We’ll have to sit down and think again,” she said. “By the way, what was that word which Euclid said when he suddenly found out how to construct an isosceles triangle? He was in his bath at the time, as well as I recollect.” A man is not in the lower sixth at Haileybury without possessing a good working knowledge of the chief events of classical antiquity. Frank rose to his opportunity. “Are you thinking of Archimedes?” he asked. “What he said was ‘Eureka’ and what he found out wasn’t anything about triangles but--” “Thanks,” said Priscilla. “It doesn’t really matter whether it was Euclid or not and it isn’t of the least importance what he found out. It was the word I wanted. Let’s agree that whichever of us Eureka’s it first stands up and shouts the word far across the sea. You’ve no objection to that, I suppose. The idea may stimulate our imaginations.”