Boys know Darby Kelly only loves gold. Dan tells Darby he dreamt of a jar of gold. They dig and find a jar. He takes it home on his back; when they smash it, he is "like a black sugar stick on a hot summer-day," not smelling like gold. He is cured
Both O'Conor and the De Marsan broadside leave off the last verse: once the jar is broken we know from the smell that Darby Kelly is not covered with gold; the missing part, only in shelfmark Firth c.20(133), [runs] "when she [his wife] saw Darby good lord! what a sight, Doubled in two on the ground there he lay, Like a black sugar stick on a hot summer-day ... I know them gasoons have disbed me complete, Never more by you I'll be led or rulled, For I may dig my grave, when I next dig Gold."
Broadsides LOCSinging sb10104a and Bodleian Harding B 18(129): H. De Marsan dating per _Studying Nineteenth-Century Popular Song_ by Paul Charosh in _American Music_, Winter 1997, Vol 15.4, Table 1, available at FindArticles site.