elongate vs heighten

elongate

verb
  • To make long or longer by pulling and stretching; to make elongated. 

  • To become long or longer by being pulled or stretched; to become elongated. 

adj
  • Lengthened, extended, elongated; relatively long and slender. 

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 elongate and heighten occurred in a corpus of books? (source: Google Ngram Viewer )