Big Smoke vs Metropolis

Big Smoke

name
  • Any large city. 

  • The city of London. 

  • The city of Dublin. 

  • The city of Toronto. 

Metropolis

name
  • a classical city site in Anatolia (Turkey). 

  • A ghost town in Elko County, Nevada, United States. 

  • A city, the county seat of Massac County, Illinois, United States. 

How often have the words Big Smoke and Metropolis occurred in a corpus of books? (source: Google Ngram Viewer )