cinematograph vs seventh art

cinematograph

noun
  • A camera that could develop its own film and served as its own projector. 

verb
  • To employ the techniques of cinematography. 

seventh art

noun
  • Chiefly preceded by the: the art of making motion pictures; filmmaking. 

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