disperse vs round up

disperse

adj
  • Scattered or spread out. 

verb
  • To break up and disappear; to dissipate. 

  • To scatter in different directions. 

  • To disseminate. 

  • To separate rays of light, etc., according to wavelength; to refract. 

  • To distribute throughout. 

round up

verb
  • To gather (cattle) together by riding around them. 

  • To round (a number) to the smallest integer that is not less than it, or to some other greater value, especially a whole number of hundreds, thousands, etc. 

  • To arrest or detain a group of people without individualized suspicion or cause, often as a form of targeted persecution. 

  • To collect or gather (something) together. 

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