condense vs heighten

condense

verb
  • To concentrate toward the essence by making more close, compact, or dense, thereby decreasing size or volume. 

  • To be transformed from a gaseous state into a liquid state. 

  • To transform from a gaseous state into a liquid state via condensation. 

heighten

verb
  • To advance, increase, augment, make larger, more intense, stronger etc. 

  • To make high; to raise higher; to elevate. 

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