lixiviate vs percolate

lixiviate

verb
  • To separate (a substance) into soluble and insoluble components through percolation; to leach. 

noun
  • leachate 

adj
  • Impregnated with salts from wood ashes. 

  • Of or relating to lye or lixivium; of the quality of alkaline salts. 

percolate

verb
  • To pass a liquid through a porous substance; to filter. 

  • To make (coffee) in a percolator. 

  • To drain or seep through a porous substance. 

  • To spread slowly or gradually; to slowly become noticed or realised. 

noun
  • A liquid that has been percolated. 

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