odometer vs tachymeter

odometer

noun
  • An instrument, usually embedded within the speedometer of a vehicle, that measures the distance the vehicle has traveled since production. 

  • A wheel used by surveyors, which registers distance traveled. 

tachymeter

noun
  • A speed indicator; a tachometer. 

  • A surveying instrument for quickly finding distances. 

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