observably vs substantially

observably

adv
  • In an observable manner. 

  • Indicates that the proposition can be verified by observation. 

  • To a detectable degree, sufficient to be observed. 

substantially

adv
  • To a great extent; in essence; essentially. 

  • Without material qualifications. 

  • In a strong substantial manner; considerably. 

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