no one told him about bushels
Jeffrey Archer's "Not a Penny More, Not a Penny Less":
Harvey Metcalfe gave precise details of his gifts to the Democratic Party. Most people do not divulge the exact amount they give to political parties, but Harvey only know about lights --- no one seemed to have told him about bushels.
question: what do "lights" and "bushels" mean here?
thank you for your help and your time.