What does that mean? If you're hoping to shoot the messenger, then I wouldn't be too quick on the draw if I were you; you may find that your powder is wet.

The text in Forbes' Cantus (link above) was published in Aberdeen, not Edinburgh, according to Simpson (The British Broadside Ballad and Its Music, 1966, 776-7 and bibliography, xxvii); but this is essentially the same as Ravenscroft: "fool", not "fu"; and more than 50 years later than Ravenscroft. The first known example with "fu" instead of "fool" is, as I said, in Kinloch's Ballad Book, 1827 (XIV, 50-54: The Man in the Moon).

Of course I ought to have been more specific, saying "the first known Scottish text including the word 'fu'; but I had naively imagined that that would be understood. There will always be people, I suppose, who are more interested in sniping at others than in arriving at the truth.