Two of the wonderful things about the Aubrey/Maturin books is the way the pleasures of good food and music run through them all - I can't wait to get stuck into a soused pig's face and a boiled baby one day! There are plenty of references to folk music as well - perhaps the best book for this is 'The Surgeon's Mate', in which the charming young Lithuanian, Jagiello, makes his first appearance and shows a deep interest in English popular songs, and they all sing 'The Lady and Death', Chevy Chase' and 'All in the Downs' in the snug of the Grapes (p.183). Does anyone know from which bawdy song Jack takes the lines
         
          You ladies of lubricity, that dwell in the bordello
          Ha ha ha, hee hee hee
          For I am that kind of fellow?

He sung this in 'Post Captain' I believe, thus causing himself great embarassment when his future wife and her family walked in!