Here is another story connected to the Fairy Knowe, from Robert Chambers in his 1826 'Popular Rhymes of Scotland'.
There was once an honest miller who lived in Menstrie. He had a pretty wife whom he loved very much. She was so beautiful that she took the fancy of the fairies who lived in the Fairy Knowe, and they took her away to live with them. It was bad enough for the miller to be without her: but every morning, although he couldn't see her, he could hear her singing.
"O! Alva woods are bonnie
Tillicoultry hills are fair
But when I think on the braes o' Menstrie
It makes my heart aye sair"
One day he was 'riddlin' some chaff at the door of his mill when he just happened to move into a particular posture: "as the hens do in rainy weather". Unknown to him this was a magical gesture, and the enchantment which bound his wife was immediately broken - suddenly there she was beside him once more.