amalgamate vs unite

amalgamate

verb
  • To merge, to combine, to blend, to join. 

  • To combine (free groups) by identifying respective isomorphic subgroups. 

  • To make an alloy of a metal and mercury. 

adj
  • Coalesced; united; combined. 

unite

verb
  • To bring together as one. 

  • To come together as one. 

noun
  • A British gold coin worth 20 shillings, first produced during the reign of King James I, and bearing a legend indicating the king's intention of uniting the kingdoms of England and Scotland. 

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