gravity bong vs vial

gravity bong

noun
  • A homemade device used to smoke marijuana, consisting of a plastic jug with the bottom cut out and immersed in a vat of water, which is then raised to create a vacuum beneath its bowl of lit marijuana. 

  • Synonym of waterfall bong 

vial

noun
  • A glass vessel or bottle, especially a small tube-shaped bottle used to store medicine, perfume or other chemicals. 

verb
  • To put or keep in, or as in, a vial. 

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