bitumen vs pitching

bitumen

noun
  • Roads sealed with bitumen, as opposed to dirt roads. 

  • Any one of the natural hydrocarbons, including the hard, solid, brittle varieties called asphalt, the semisolid maltha and mineral tars, the oily petrolea, and even the light, volatile naphthas. 

  • A sticky, black, highly viscous liquid or semi-solid form of petroleum, burning with a bright flame. It occurs as an abundant natural product in many places, as on the shores of the Dead and Caspian Seas. It is used in cements, in the construction of pavements, etc.; Mineral pitch. 

  • Canadian deposits of extremely heavy crude oil. 

verb
  • To cover or fill with bitumen. 

pitching

noun
  • The rough paving of a street to a grade with blocks of stone. 

  • The act of throwing or casting. 

  • A facing of stone laid upon a bank to prevent wear by tides or currents. 

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