Here's the O'Lochlainn tune (Roberto beat me to posting the words!).
Mick
X: 1 T:Farewell, Dearest Nancy M:6/8 L:1/8 B:O'Lochlainn: More Irish Street Ballads K:Cm G|(F/E/) C C|A G> G|F (E/C/) (C/D/)|(E/C/) B, w:Fare-well_ dear-est Nan-cy for now I_ must_ leave_ you, C/>D/|E F (G/=A/)|B c> G|(G/F/) D F|G2 w:To the burn-ing West_ In-dies my course_ for to steer, (E/F/)|G c> c|B c> G|F (E/C/) (C/D/)|(E/C/) B, w:I_ know ver-y well that the par-ting_ will_ grieve_ thee, C/D/|E F (G/=A/)|B c> G|(F/E/) C C|C2|| w:But, my love, I'll re_turn in the spring_ of the year.