concentrate vs converge

concentrate

verb
  • To bring to, or direct toward, a common center; to unite more closely; to gather into one body, mass, or force. 

  • To focus one's thought or attention (on). 

  • To approach or meet in a common center; to consolidate. 

  • To increase the strength and diminish the bulk of, as of a liquid or an ore; to intensify, by getting rid of useless material; to condense. 

noun
  • A substance that is in a condensed form. 

converge

verb
  • (said of two or more entities) To approach each other; to get closer and closer. 

  • (said of a sequence or series) To have a (finite, proper) limit. 

  • (said of an iterative process) To reach a stable end point. 

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