palanquin vs tilbury

palanquin

noun
  • A covered type of litter for a stretched-out passenger, carried on four poles on the shoulders of four or more bearers, as formerly used (also by colonials) in eastern Asia. 

tilbury

noun
  • A small open two-wheeled carriage. 

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