64 THE WORLD. 



the astronomical year. In 1582 this difference had accumulated, 

 until it amounted to over 11 days, of course the. equinoxes, and sol- 

 stices, no longer happened on those days which had been appointed 

 to them, and the celebrations of the Church festivals, were conse- 

 quently much deranged. The Council of Nice, which sat A. D. 

 325, had decreed that the great festival of Easter, should be 

 celebrated in conformity with the Jewish Passover, which was 

 regulated by the full moon following the vernal equinox. Now 

 the decree did not say that this festival, upon which all the others 

 depend, should be on the first Sunday after the full moon following 

 the vernal equinox, but on the Sunday following the full moon, 

 O7i or after the 2isi of March, this being the day, at that time, of 

 the vernal equinox. Pope Gregory XIII., who occupied the 

 pontificate in 1582, determined to rectify this error, which was 

 thus made known, not from any series of observations for that 

 specific purpose, as at the present day, but by the accumulated 

 error becoming so great as to introduce confusion. At this time 

 the vernal equinox really occurred, according to the civil reckoning j 

 on the llth of March, ten days earlier than the time decreed by 

 the Nicene Council. To remedy this defect, Gregory directed 

 that the day following the 4th of October, 1582, should be reckoned 

 the 15th, instead of the 5th, thus restoring the vernal equinox to 

 its former position, by omitting altogether ten days. To prevent 

 the accumulation, he directed the intercalary day to be omitted 

 on every centurial year ; this would have answered every purpose 

 if the difference, which had caused the error, had amounted to a 

 day in 100 years, but it did not, for it was but a little more than f of 

 a day, hence omitting the intercalary day every 100th, or centurial 

 year, omitted of a day too much, which, in the course of 400 

 years, amounts to 1 day. It was, therefore, further provided, that 

 although the intercalary day was ordinarily omitted each centurial 

 year, it was to be retained every 400th year, thus the centurial 

 years 1600, 2000, and 2400, are bissextile ; but the years 1500, 

 1700, 1800, 1900, 2100, 2200, &c., are common years. This 

 correction is sufficiently accurate for all purposes, the slight re- 

 maining error will only amount to a day after an interval of 144 

 centuries. The time of the vernal equinox now is, and always 



