burnable vs napalm

burnable

noun
  • Anything that can be burned. 

adj
  • Able to be burned; combustible 

napalm

noun
  • A highly flammable, viscous substance, designed to stick to the body while burning, used in warfare as an incendiary especially in wooded areas. 

verb
  • To spray or attack with napalm. 

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