they all snort and jeer and tell me i 'd just be carrying coals to newcastle and i say , `` if newcastle wants coals , i 'll haul 'em , '' and they jeer and say , `` that 's where coals come from , ye twit , '' and i say , `` i do n't care if it 's fish heads , a cargo is a cargo , '' and i will increase and prosper , they 'll see .