The correction of the Metonic 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.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
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