bath vs light water

bath

noun
  • The body of liquid one bathes in. 

  • A substance or preparation in which something is immersed. 

  • A tub or pool which is used for bathing: bathtub. 

  • The act of bathing. 

  • A former Hebrew unit of liquid volume (about 23 L or 6 gallons). 

  • A building or area where bathing occurs. 

verb
  • To wash a person or animal in a bath. 

  • To bathe (oneself); to have a bath. 

light water

noun
  • Foam formed by water and a fluorocarbon surfactant, used in firefighting because it floats on flammable liquids lighter than water. 

  • Water in its standard form of H₂O, containing two protium hydrogen atoms, as opposed to heavy water. 

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