percolate vs permeate

percolate

verb
  • To drain or seep through a porous substance. 

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

  • To make (coffee) in a percolator. 

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

noun
  • A liquid that has been percolated. 

permeate

verb
  • To pass through the pores or interstices of; to penetrate and pass through without causing rupture or displacement; applied especially to fluids which pass through substances of loose texture 

  • To enter and spread through; to pervade. 

noun
  • Liquid that has passed through a filtration system. 

  • A watery by-product of milk production. 

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