METON1C CYCLE, ante. The discovery of the Metonic cycle forms an era in the history of the early astronomy of Greece. The Chaldeans established several 'luni-solar periods; and the difficulty of reconciling the 'notions of the sun and MOOD, or of assign ing a period at the end of which these two luminaries again occupy the same positions relatively to the stars, had long embarrassed those who had the care of regulating the festivals. The discovery of Meton, therefore, which was brought into use on July 16, 433 n.c., was received with acclamation by the people assembled at the Olympic games, and adopted in all the cities and colonies of Greece. It was also engraved in golden let ters on tables of brass, whence it received the appellation of the golden' number, and has been the basis of the calendars of all the nations of modern Europe. It is still in eccle siastical use, with such modifications as time has rendered neceseary.—The period of
Met= consisted of twelve years, containing twelve months each, and seven years con taining thirteen months each; and. these last formed the 3d, 5th, 8th, llth, 13th, 16th, .and 19th years of the cycle. He divided the cycle into 123 full months of 30 days, and 110 deficient months of 29 days each; the whole exceeding 19 revolutions of the sun by 9f hours, and exceeding 235 lunations by 7,1 hours. A century after Meton, his cycle -was corrected by Calippus by quadrupling the period of 6,940 days, and deducting one day at the end of that time by changing one of the full ihontlis into a deficient month. By this change the error of lunstion was reduced to one day in 304 years. The calen dar, as laid down by Ideler, was as follows: