blowgun vs tear gas

blowgun

noun
  • A hollow tube through which a dart or similar missile may be blown. 

tear gas

noun
  • Any lachrymatory, non-lethal chemical compound that causes the eyes to sting and water and/or irritates the respiratory system, mostly used for controlling crowds during riots or as self-defense. 

verb
  • To use tear gas. 

How often have the words blowgun and tear gas occurred in a corpus of books? (source: Google Ngram Viewer )