residuum vs tailings

residuum

noun
  • The residue, remainder or rest of something. 

  • The residue of an estate. 

  • The solid material remaining after the liquid in which it was dissolved has been evaporated; a residue. 

  • A binary function from [0,1] × [0,1] to [0,1] which is defined in terms of the t-norm as follows: x→y= sup z|z*x⩽y, where * denotes the t-norm function and sup denotes the supremum. 

tailings

noun
  • The feints, the last fraction of product obtained at the end of distillation. 

  • The waste that remains after the minerals have been extracted from an ore by ore dressing. 

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