METONIC CYCLE ( so railed from its in ventor, Teton. who flourished at Athens about me. 43'2). A cycle of nineteen years of 235 lunar months, or 0940 days. at the end of which time the new moon falls on the same day of the year as it did at the beginning of the cycle• and eclipses recur in nearly the same order. This arises from the circumstance that 19 solar years arc nearly equal to 235 lunations, their average values being 6939.68835 and 6939.60249 days respectively. As the Greek States reckoned by lunar months, and on this reckoning depended the recurrence of many re ligious festivals, while on the other hand certain other rites were connected with the recurrence of the seasons, there was a constant effort to bring the solar year (365 days. 5 hours, 4S minutes, 46 seconds) into accord with the period of twelve lunar months (354 days, S hours, 48 minutes, 33.6 seconds). Before Meton the favorite cycle was the Octaeteris (or, as it was sometimes called, Enncatcris), of eight years with three intercalary months of 30 days. The inaccuracy thus arising
was removed by Meton, who in the period of 19 years inserted 7 intercalary months, of which 5 had 30 and 2 had 29 days. They were inserted in the 3d, Gth, Sth, Ilth, 14th. 17th. and 19th years. The slight inaccuracy that remained was reduced by Callippus about a century later, by combining four Sletonie periods into a 'great year' of 76 calendar years. and omitting one day in the intercalation, obtaining 27,759 days. The details of ?leton's cycle are not very clear, and there is considerable difference of opinion among scholars in regard to them. Unger places the beginning of Meton's cycle on July 111th. mc. 432; Oppert on July 25th, B.C. 433. It is agreed that the Callippic cycle began June 29th, me. 330. The Attic calendar, as laid down by Unger, is as follows: rendu de l'Academie des Inscriptions et Belles Lcttres (Paris, 189S).