chimney pot vs flue

chimney pot

noun
  • A short earthenware pipe, placed on top of a chimney to improve the draft. 

flue

noun
  • A pipe or duct that carries gaseous combustion products away from the point of combustion (such as a furnace). 

  • In an organ flue pipe, the opening between the lower lip and the languet. 

  • An enclosed passageway in which to direct air or other gaseous current along. 

How often have the words chimney pot and flue occurred in a corpus of books? (source: Google Ngram Viewer )