ember vs pilot burner

ember

noun
  • A glowing piece of coal or wood; a hot coal. 

  • Smoldering ash. 

adj
  • Making a circuit of the year or the seasons; recurring in each quarter of the year, as certain religious days set apart for fasting and prayer. 

pilot burner

noun
  • Synonym of pilot light (“persistent flame to ignite gas”) 

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