chimney stack vs lum

chimney stack

noun
  • A vertical structure, normally of brick, rising from a roof, containing one or more flues, each one terminating in a chimney pot. 

lum

noun
  • A chimney; also, the top part of a chimney. 

  • A ventilating chimney over the shaft of a mine. 

  • A deep pool, especially one in a riverbed. 

  • A grove or wood; also, a woody valley. 

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