metronome vs speedometer

metronome

noun
  • A device, containing an inverted pendulum, used to mark time by means of regular ticks at adjustable intervals; an electronic equivalent that emits flashes. 

speedometer

noun
  • Such a device incorporating an odometer. 

  • An instrument located within the dashboard of a vehicle that measures and indicates the current speed of the vehicle. 

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