Borstal vs Seal

Borstal

name

  • A suburb, formerly a village, in Rochester, Medway borough, Kent, England (OS grid ref TQ7366). 

Seal

name

  • A village in Sevenoaks district, Kent, England. 

  • A surname. 

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