Urgh. Sunday morning brain. Corrected version:

Brendán Breathnach deals relatively extensive with Bunting's work, within the context of his 'Folk music and dances of Ireland'. All praise for the work aside he goes into the way Bunting adapted the melodies he collected a bit. I won't quote all of it (see p. 105-107 of FMaDoI).

'Bunting tells us that thirty was the usual number of strings found on the Irish harps at the Belfast meeting in 1792, and that the system of tuning was such that only two major scales, G and C, were perfect in their diatonic intervals. When the F strings were tuned t o F sharp, the tuning was G major; when these strings were tuned to F natural, the tuning was C major. In fact, in so far as tuning was involved, the harp was like a piano which had no black notes. Nothwithstanding this, a great many of Bunting's airs are set in keys the harpers could not have used; more surprisingly, his music is speckled with accidentals, for which they lacked strings. [...] In effect, what Bunting did was to alter the melody to fit what he considered to be correct and suitable harmonies. He may indeed have persuaded himself that he was correcting or improving the music'