metronome vs tattler

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. 

tattler

noun
  • A device fitted to a vehicle to measure mileage etc. 

  • Either of two similar bird species in the shorebird genus Heteroscelus (Tringa in some taxonomies). 

  • One who tattles (notifies authorities of illicit behavior) or is inclined to do so; a tattletale. 

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