Night after night they met, and swam about in the dark clear lake, where such was the prince’s gladness, that (whether the princess’s way of looking at things infected him, or he was actually getting light-headed) he often fancied that he was swimming in the sky instead of the lake. But when he talked about being in heaven, the princess laughed at him dreadfully.
When the moon came, she brought them fresh pleasure. Everything looked strange and new in her light, with an old, withered, yet unfading newness. When the moon was nearly full, one of their great delights was to dive deep in the water, and then, turning round, look up through it at the great blot of light close above them, shimmering and trembling and wavering, spreading and contracting, seeming to melt away, and again grow solid. Then they would shoot up through the blot, and lo! there was the moon, far off, clear and steady and cold, and very lovely, at the bottom of a deeper and bluer lake than theirs, as the princess said.
The prince soon found out that while in the water the princess was very like other people. And besides this, she was not so forward in her questions or pert in her replies at sea as on shore. Neither did she laugh so much; and when she did laugh, it was more gently. She seemed altogether more modest and maidenly in the water than out of it. But when the prince, who had really fallen in love when he fell in the lake, began to talk to her about love, she always turned her head towards him and laughed. After a while she began to look puzzled, as if she were trying to understand what he meant, but could not—revealing a notion that he meant something. But as soon as ever she left the lake, she was so altered, that the prince said to himself, “If I marry her, I see no help for it: we must turn merman and mermaid, and go out to sea at once,”
The princess’s pleasure in the lake had grown to a passion, and she could scarcely bear to be out of it for an hour. Imagine then her consternation, when, diving with the prince one night, a sudden suspicion seized her that the lake was not so deep as it used to be. The prince could not imagine what had happened. She shot to the surface, and, without a word, swam at full speed towards the higher side of the lake. He followed, begging to know if she was ill, or what was the matter. She never turned her head, or took the smallest notice of his question. Arrived at the shore, she coasted the rocks with minute inspection. But she was not able to come to a conclusion, for the moon was very small, and so she could not see well. She turned therefore and swam home, without saying a word to explain her conduct to the prince, of whose presence she seemed no longer conscious. He withdrew to his cave, in great perplexity and distress.
Next day she made many observations, which, alas! strengthened her fears. She saw that the banks were too dry; and that the grass on the shore, and the trailing plants on the rocks, were withering away. She caused marks to be made along the borders, and examined them, day after day, in all directions of the wind; till at last the horrible idea became a certain fact—that the surface of the lake was slowly sinking.