copper vs mercury

copper

noun
  • A reddish-brown, malleable, ductile metallic element with high electrical and thermal conductivity, symbol Cu, and atomic number 29. 

  • The reddish-brown colour/color of copper. 

  • A police officer. 

  • Any of various lycaenid butterflies with copper-coloured upperwings, especially those of the genera Lycaena and Paralucia. 

adj
  • Made of copper. 

  • Having the reddish-brown colour/color of copper. 

verb
  • To sheathe or coat with copper. 

mercury

noun
  • A silvery-colored, toxic, metallic chemical element, liquid at room temperature, with atomic number 80 and symbol Hg. 

  • One of the elemental principles formerly thought to be present in all metals. 

  • Any plant of any species of the genus and the genus Mercurialis. 

  • The poison oak or poison ivy. 

  • An annual plant, annual mercury (Mercurialis annua), formerly grown for its medicinal properties; French mercury, herb mercury. 

  • Ambient pressure or temperature (from the use of mercury in barometers and thermometers). 

  • A similar edible plant (Blitum bonus-henricus), otherwise known as English mercury or allgood. 

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