ether vs welkin

ether

noun
  • The medium breathed by human beings; the air. 

  • The sky, the heavens; the void, nothingness. 

  • Starting fluid. 

  • Diethyl ether (C₄H₁₀O), an organic compound with a sweet odour used in the past as an anaesthetic. 

  • A particular quality created by or surrounding an object, person, or place; an atmosphere, an aura. 

  • Any of a class of organic compounds containing an oxygen atom bonded to two hydrocarbon groups. 

  • The atmosphere or space as a medium for broadcasting radio and television signals; also, a notional space through which Internet and other digital communications take place; cyberspace. 

  • Often as aether and more fully as luminiferous aether: a substance once thought to fill all unoccupied space that allowed electromagnetic waves to pass through it and interact with matter, without exerting any resistance to matter or energy; its existence was disproved by the 1887 Michelson–Morley experiment and the theory of relativity propounded by Albert Einstein (1879–1955). 

verb
  • To viciously humiliate or insult. 

welkin

noun
  • The upper atmosphere occupied by clouds, flying birds, etc. 

  • The place above the Earth where God or other deities live; heaven. 

  • The sky which appears to an observer on the Earth as a dome in which celestial bodies are visible; the firmament. 

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