The words are by "Mrs. Grant", presumably Mrs. Grant of Laggan (1755-1838), since her sort of relative Mrs. Grant of Carron is the author of only one song, it seems, namely "Roy's Wife of Aldivalloch". Anyway, the song was published by Thomson in Edinburgh in 1818, in "A Select Collection of Original Scottish Airs..." with accompaniments by Beethoven and Haydn. Beethoven gave an opus no. to this lot, "Twenty-five Scottish Songs", opus 108 (the only ones he did give an opus no. to). Thomson supplied the tune to him; where it came from is another question. Is this any help??