gamba vs viola d'amore

gamba

noun
  • A rank of organ pipes, so called for a supposed resemblance of the sound to that of a viola da gamba. 

  • The metacarpus or metatarsus of ruminants, etc. 

viola d'amore

noun
  • A 7- or 6-stringed musical instrument similar to the treble viol, used chiefly in the Baroque period. 

How often have the words gamba and viola d'amore occurred in a corpus of books? (source: Google Ngram Viewer )