atlatl vs machine gun

atlatl

noun
  • A spearthrower consisting of a wooden stick with a thong or perpendicularly protruding hook on the rear end that grips a grove or socket on the butt of its accompanying spear (or dart), intended to steady the spear immediately prior to throwing, to increase its potential range when thrown, and to increase its force of penetration of the target. 

machine gun

noun
  • A type of fully automatic firearm that fires bullets in rapid succession by a single action of the trigger and is capable of sustained fire. 

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