Ferule or Ferrule: How To spell?
The word Ferule is misspelled against Ferrule, a noun meaning "A bushing for expanding the end of a flue to fasten it tightly in the tube plate, or for partly filling up its mouth."
The word Ferule is misspelled against Ferrule, a noun meaning "A bushing for expanding the end of a flue to fasten it tightly in the tube plate, or for partly filling up its mouth."