Big Ben vs stopwatch

Big Ben

name
  • The hour bell in the Elizabeth Tower (formerly known as the Clock Tower), adjacent to the Houses of Parliament in Westminster, London, United Kingdom. 

  • The clock tower itself. 

stopwatch

noun
  • A timepiece designed to measure the amount of time elapsed between a particular time when activated and when the piece is deactivated. 

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