contiguous vs firsthand

contiguous

adj
  • Connecting without a break. 

  • Connected; touching; abutting. 

  • Adjacent; neighboring. 

firsthand

adj
  • Direct, without intermediate stages. 

  • Not previously owned or used; contrasted with secondhand. 

adv
  • Directly or from personal experience. 

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