beau idéal vs the bee's knees

beau idéal

noun
  • Ideal excellence, or an imaginary standard of perfection. 

  • An emulable eidolon embodying excellence in a particular respect. 

the bee's knees

noun
  • Something or someone excellent, surpassingly wonderful, or cool. 

  • Used other than figuratively or idiomatically: see bee, -'s, knee. Corbiculae. 

How often have the words beau idéal and the bee's knees occurred in a corpus of books? (source: Google Ngram Viewer )