hydraulic vs seawater

hydraulic

adj
  • Pertaining to water. 

  • Related to, or operated by, hydraulics. 

verb
  • To mine using the technique of hydraulic mining. 

seawater

adj
  • Consisting of seawater. 

  • Associated in some way with seawater, or intended for dealing with seawater. 

noun
  • The saltwater of a sea or ocean. 

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