bow and arrow vs nerve gas

bow and arrow

noun
  • A weapon consisting of a bow and a supply of arrows, often kept in a quiver. 

nerve gas

noun
  • A toxic chemical compound and banned weapon of mass destruction which, when inhaled or ingested, impairs nervous system functions, typically causing extreme physical distress and death by asphyxiation. 

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