violin vs watchman's rattle

violin

noun
  • A small unfretted stringed instrument with four strings tuned (lowest to highest) G-D-A-E, usually held against the chin and played with a bow. 

  • Any instrument of the violin family, always inclusive of violins, violas, and cellos and sometimes further including the double bass. 

  • The position of a violinist in an orchestra or group. 

verb
  • To play on, or as if on, a violin. 

watchman's rattle

noun
  • An instrument, with a vibrating tongue fixed in a frame, which slips over the teeth of a ratchet wheel and produces a loud raucous sound when whirled around, once used by watchmen to warn of danger 

How often have the words violin and watchman's rattle occurred in a corpus of books? (source: Google Ngram Viewer )