“Let’s just go out to the end of the rocks,” Francis urged, “just to see what it’s like where the water gets deep and the seaweed goes swish, swish, all long and lanky and grassy, like in the Sabrina picture.” “Halfway then, not more,” said Mavis, firmly, “it’s dangerous—deep outside—Mother said so.” And halfway they went, Mavis still cautious, and Francis, after his wetting, almost showing off in his fine carelessness of whether he went in again or not. It was very jolly. You know how soft and squeezy the blobby kind of seaweed is to walk on, and how satin smooth is the ribbon kind; how sharp are limpets, especially when they are covered with barnacles, and how comparatively bearable to the foot are the pale primrose-colored hemispheres of the periwinkle. “Now,” said Mavis, “come on back. We’ll run all the way as soon as we get our shoes and stockings on for fear of colds.” “I almost wish we hadn’t come,” said Francis, turning with a face of gloom. “You didn’t really think we should find a Mermaid, did you?” Mavis asked, and laughed, though she was really annoyed with Francis for getting wet and cutting short this exciting morning game. But she was a good sister. “It’s all been so silly. Flopping into that pool, and talking and rotting, and just walking out and in again. We ought to have come by moonlight, and been very quiet and serious, and said— “‘_Sabrina fair, Listen where thou art sitting—_’” “Ow—Hold on a minute. I’ve caught my foot in something.” Mavis stopped and took hold of her brother’s arm to steady him; and as she did so both children plainly heard a voice that was not the voice of either of them. It was the sweetest voice in the world they thought, and it said: “Save her. We die in captivity.” Francis looked down and had a sort of sudden sight of something white and brown and green that moved and went quickly down under the stone on which Mavis was standing. There was nothing now holding his foot. “I say,” he said, on a deep breath of awe and wonder, “did you hear that?” “Of course, I heard it.” “We couldn’t both have fancied it,” he said, “I wish it had told us who to save, and where, and how—” “Whose do you think that voice was?” Mavis asked softly. “The Mermaid’s,” said Francis, “who else’s could it have been?” [Illustration: “_We die in captivity._”] “Then the magic’s really begun—” “Mermaids aren’t magic,” he said, “anymore than flying fishes or giraffes are.” “But she came when you said ‘Sabrina fair,’” said Mavis. “Sabrina wasn’t a Mermaid,” said Francis firmly. “It’s no use trying to join things on when they won’t. Come on, we may as well be getting home.” “Mightn’t she be?” suggested Mavis. “A Mermaid, I mean. Like salmon that live in rivers and go down to the sea.”