Calendar

Calendar (Latin Calendae, the first day of the Roman month), an orderly division of time into years, months, and other periods in accordance with the phenomena attending the revolutions of the heavenly bodies. At a very early period a solar year of 355 days was in use among the Egyptians. But among other nations the changes of the moon first suggested the idea of a regular division of time, and, when the year was introduced, it was made to consist of 12 months of 29 or 30 days. The discrepancy between this lunar year and the solar year soon became manifest, and attempts were made to remedy the defect by inserting at fixed intervals an additional or "intercalary" month. Thus the Jewish year consisted of 12 months of 30 and 29 days alternately; an additional month was introduced in 7 out of every 19 years, and over and above this one or two days were sometimes added. The Attic year also contained 12 months of 30 and 29 days alternately; it was consequently 11-1/4 days shorter than the solar year of 365 days 6 hours, and in 8 years the difference amounted to 90 days. This led to the introduction of a cycle of 8 years, three of which contained an intercalary month. But as the exact length of the solar year is 365 days 5 hours 48 minutes 49 seconds, this cycle contained about 1-1/2 hour too much. The difference was adjusted by a new cycle of 19 years, attributed to Meton (432 B.C.). The earliest Roman year, the "Romulian," is said to have been divided into 10 months, containing in all 304 days. It was superseded during the period of the kings by a lunar year of 355 days. The intercalary system was adopted at Rome, but very inefficiently applied, till 45 B.C., when Julius Caesar instituted the Julian calendar. Adherence to this system was enforced by the Romans throughout their empire; it passed from them to the Christian states of Europe, and, except for the reform introduced by Pope Gregory, has remained unchanged up to the present time. Caesar assigned to each month the number of days which it still retains, and made allowance for the additional 6 hours by adding an intercalary day at the end of February in every fourth year (bissextile or leap year). But, as in the case of the Athenian cycle of 8 years, the year was estimated at about 11 mins. 11 sees, more actual length, and by 1582 had advanced 10 days beyond its original starting point, the vernal equinox falling on the 11th instead of the 21st of March. In that year, accordingly, Pope Gregory XIII. enacted that the days between the 4th and 15th of October should be omitted, and what would have been the 5th became the 15th of the month. To prevent a repetition of the error, he also enacted that the first year of a century should be reckoned as leap-year once only in the course of 400 years. Thus 1700 and 1800 were not leap years, but 2000 will be one. The new style was immediately adopted in Italy, Spain, Portugal, and the Roman Catholic portion of the Netherlands, and in the next two years in those parts of Germany and Switzerland which acknowledged the authority of the Pope. Religious prejudice retarded its acceptance by the Protestants of Germany. Switzerland, and the Netherlands till 1700. England retained the old method of computation until 1752, when, by an Act of Parliament passed in the preceding year, 11 days were omitted, the 3rd of September being reckoned as the 14th. The reform also made its way into Sweden about the middle of the eighteenth century. Russia and Greece still adhere to the old method, and the difference between their calendar and ours is now 12 days, e.g., our 28th of May is with them the 9th of June.

The Mohammedans employ a lunar year of 354 days, but during a cycle of 30 years they eleven times add a day at the end of the vear, so that the number of days is then increased to 355. It of course follows from this arrangement that the beginning of their year does not correspond with any fixed point in the course of the solar year.

During their first revolution the French adopted a new calendar, the use of which was decreed by the Convention in 1793. The year was divided into 12 months of 30 days each, which received their names from the most striking aspect of Nature at the time of their occurrence. The first, Vindemiaire, began on the 22nd of September, the last day of Fructidor fell on the 16th of the same month; there was thus a surplus of 5 days, which were devoted to the observance of great national fetes. This system was. abolished by Napoleon on the 10th of Nivose. year of the Republic XIV. (December 31,. 1805).