CALENDARS, ETC.
Reading edition
Our year is a little more than 365 days in length—in fact, nearly 365¼. Because of this fact, an extra day accumulates every four years; and to include this we add this extra day to February every “leap year.” In this way, our celestial bookkeeping is kept fairly accurate. Twelve months of 30 days each would give 360 days, with five days over. It was, however, found that five days was not enough, while five and a quarter was too much. It is interesting to note that Hipparchus, who flourished in the 2nd century B. C., worked on this problem, and fixed 5 days and 55 m., as the time required—a truly remarkable achievement, since it has since been found to be accurate to within less than six minutes.