Genre: old time juvenile fiction
Summary: There once was a princess who was cursed from birth to remain lighter than air until a prince saves her. She is threatened by the smallest breeze but in the water, she has her normal weight. When her beloved pond begins to disappear, she is distraught, but seeing as a young handsome prince is already in love with her, he offers himself as a sacrifice to plug the hole. As he is nearing his death, the princess realizes what he must feel to sacrifice so much and she loves him back and her curse is lifted!
Response: I am arguing that this is pre-1920's YA lit because even though this sounds like a fairy tale for children George MacDonald had several rather grown up fairy tales with much deeper meanings than would be noticed by younger children.