Well this is all very interesting stuff. Let me give you another angle. I have a feeling that we should consider Bob Boltons point, that Newton may in fact have just written a poem! It is interesting that no one has considered the subject of the song. Whats is it all about? I was brought up during the first 20 years of my folk song career in the North of England in the 60's and 70's. and almost all the folk singers who sang this at the time told the story that this song (?poem) was inspired by the heroics of Grace Darling, a light house keepers daughter,off the coast of Northumberland, who tied a rope to herself and along with her Father plucked 7or8 shipwrecked seamen from the water at the foot of the light house before being swept to sea herself. I believe that this story hit the newspapers of the time. The words are supposed to be deliberately ambiguous and the play on the name Grace was intened to be a tribute to Grace Darling and the Lord at one and the same time. I need to go back to the Life Boat Association Museum in Whitby, North Yorkshire to check the date of Grace Darlings death. If this is pre 1893 as Dale Rose pin points Newton death then this theory on the lyrics could indeed be true. I know nothing about the tune.