demountable vs removable

demountable

adj
  • Able to be removed from its mount; designed to be dismantled. 

noun
  • A temporary and portable building, especially a portable classroom in a school. 

removable

adj
  • Able to be removed. 

noun
  • Something that can be removed. 

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