dray vs palanquin

dray

noun
  • A low horse-drawn cart, often without sides, and used especially for heavy loads. 

  • A kind of sledge or sled. 

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. 

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