E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Callippic Period.
The correction of the Meton’ic cycle by Callippos. In four cycles, or seventy-six years, the Metonic calculation was seven and a-half in excess. Callippos proposed to quadruple the period of Meton, and deduct a day at the end of it: at the expiration of which period Callippos imagined that the new and full moons returned to the same day of the solar year.
