Molotov cocktail vs atom bomb

Molotov cocktail

noun
  • A crude incendiary bomb made from a glass bottle, either filled with a flammable liquid such as petroleum and supplied with a rag for a fuse that is lit just before being hurled, or filled with such a mix of flammable liquids that it ignites itself when it is smashed and its contents are exposed to air. 

atom bomb

How often have the words Molotov cocktail and atom bomb occurred in a corpus of books? (source: Google Ngram Viewer )