or Rhabdology, is arithmetic, a name given by Napier to a method of performing some of the more difficult operations of numbers by means of certain square little rods. Upon these are inscribed the simple numbers; then by shifting them according to certain rules, those operations are performed by simply adding or subtracting the numbers as they stand upon the rods. See Napier's Rhabdologia, printed in 1617. See also the article Napier's Bones.