alertness vs brooding

alertness

noun
  • The quality of being alert or on the alert 

brooding

noun
  • A spell of brooding; the time when someone broods. 

adj
  • Broody; incubating eggs by sitting on them. 

  • Deeply or seriously thoughtful. 

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