• This neglected centesimal was the omission of some inconsiderable fraction or centesimal part, in the computation of the year according to the Julian calendar, which was corrected in the Gregorian, some two centuries and a half after Dante’s death. By this error, in a long lapse of time, the months would cease to correspond to the seasons, and January be no longer a winter, but a spring month. Sir John Herschel, Treatise on Astronomy , Ch. XIII , says:⁠— “The Julian rule made every fourth year, without exception, a bissextile. This is, in fact, an over-correction; it supposes the length of the tropical year to be 365¼ d. , which is too great, and thereby induces an error of 7 days in 900 years, as will easily appear on trial. Accordingly, so early as the year 1414, it began to be perceived that the equinoxes were gradually creeping away from the 21st of March and September, where they ought to have always fallen had the Julian year been exact, and happening (as it appeared) too early. The necessity of a fresh and effectual reform in the calendar was from that time continually urged, and at length admitted.