be- vs per-

be-

prefix
  • As an intensifier; i.e. thoroughly, excessively; completely; utterly. 

  • About, regarding, concerning, over. 

  • By, near, next to, around, close to. 

  • On, upon, at, to, in contact with something. 

  • Forming verbs derived from nouns or adjectives, usually with the sense of "to make, become, or cause to be". 

  • Around; about. 

  • Off, away, over, across 

  • All around; about; abundantly; all over. 

per-

prefix
  • In adjectives and adverbs: denoting the sense "extremely", as in perfervid. 

  • In verbs: denoting the sense "through", as in perforate. 

  • In verbs: denoting the sense "to destruction", as in pervert. 

  • Forming nouns and adjectives denoting the maximum proportion of one element in a compound, as in peroxide. 

  • Denoting the sense "by" or "per", as in perchance or perhaps. 

  • Added to the name of an element in a polyatomic ion to denote the number of atoms of that element (usually four). 

  • In verbs: denoting the sense "thoroughly", as in perfect. 

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