CALENDAR
108
CALENDAR
3 sqq.; Lev., xxiii, 10-12), might have fallen in
the middle of winter; and some other festivals
depending likewise on the products of the seasons
would also have been materially interfered with.
Hence it was soon felt — how soon cannot now be
ascertained — that the difference between the lunar
and the solar years should be equalized by the inter-
calation of a month. The year in which such an in-
tercalation should be made was for a while deter-
mined by an authoritative decision of the Sanhedrin,
and ultimately tixed in a permanent manner by
astronomical calculation. In a cycle of nineteen
years the third, sixth, eighth, eleventh, fourteenth,
seventeenth, and nineteenth are made leap-years with
an average length of 384 days, by w the addition of a
month following the twelfth ('Adar), and usually
called We-' Adar (Second Adar). It is plain, there-
fore, that the Jewish year has long been, and still is,
a hmi-solar year. The Hebrew year thus far de-
scribed is one constituted in harmony with ritual re-
quirements, and hence it is called the sacred Jewish
year. Together with it the Jews have had from time
immemorial what may be called a common or civil
year commencing in the month of Tishri (correspond-
ing generally to part of September and part of Octo-
ber), on or immediately after the new moon following
the autumnal equinox. The beginning of the
Hebrew civil year practically coincides with that of
seed time in Palestine, while the beginning of the
sacred year corresponds to that of the harvest season
in the same country.
There now remains to consider the Era, or last ele- ment of the Jewish calendar. As might well be ex- pected in connexion with a people whose history lias been so checkered, the Hebrews have adopted various points of time from which to reckon the succession of years. Their principal ancient eras have been: (1) the one which was dated from the deliverance from Egypt; (2) the regnal era, or computation of time from the year of accession of the Jewish kings to the throne; (3) the Seleucid era, introduced after the Babylonian Exile, beginning 312 b. c, and used by the Jews probably till the twelfth century. For cen- turies they have employed their present method of counting by anno mundi (a. m.). For the yearly arrangement of the principal festival days see Jewish calendar on preceding page.
According to the current Jewish reckoning the calendar is dated from the Creation of the World, which is considered to have taken place 3760 years and 3 months before the commencement of the Chris- tian Era. To find the number of the Hebrew year, beginning in the autumn of a given year of our com- mon era, we have to add 3761 to the number of the latter. Thus the Jewish year beginning September, 1908, is 5669 a. m.
WooLiiorsK, Measure Wrights, and Moneys of All Nations (18691; SrnrHEH, lliston of the Jewish Prople.tr. 1st Div.vol. II (2d ml.); Edehsheim, The Temple and t's Services in the Time of Jesus Christ; Barnaby, The Jewish anil Mohammedan Calen-
dar (1901).
Francis E. Gigot.
Calendar, Reform op the. — For the measurement
of time the most important units furnished by natural
phenomena are the Day and the Year. In regard of
both, it is convenient and usual to speak of the appar-
ent movements of the sun and stars as if they were
real, and not occasioned by the rotation and revolu-
tion of the earth.
The Day is the interval between two successive passages of the sun across the meridian of any place. It h commonly computed from the midnight passage across tin- inferior meridian on the opposite side of the globe; but by astronomers from the passage at the noon following. The Civil Day is thus twelve hours in advance of the Astronomical.
The Solar Day, which is what we always mean by the term day, is longer by about four minutes of
time than the Sidereal, or the successive passages of a
fixed star across the same meridian; for, owing to the
revolution of the earth in its orbit from west to east,
the sun appears to travel annually in a path (the
ecliptic), likewise from west to east, among the stars
round the entire heavens. The belt of constellations
through which it appears to proceed is styled the
zodiac. During half the year (March to September)
the ecliptic lies to the north of the celestial equator;
during the other half (September to March) to the
south. The points where ecliptic and equator inter-
sect are called the equinoxes. In the northern hemi-
sphere the March equinox (or "first point of Aries")
is called the vernal equinox; the September equinox
("first point of Libra"), the autumnal.
The Year (Tropical Year) is the period in which the sun makes a complete circuit of the heavens and re- turns to the point in the zodiac whence it started, and the problem to be solved by those who construct calendars is to find the exact measure of this yearly period in terms of days, for the number of these occu- pied by the sun's annual journey is not exact. Tak- ing the venial equinox as a convenient starting-point, it is found that before the sun arrives there again, 365 days and something more have passed. These are, of course, solar days; of sidereal days, each shorter by four minutes, there are 366. The first attempt to find a practical solution of this problem was made by Julius Csesar, who introduced the Julian Calendar. With the assistance of the astronomers of Alexandria, he determined the true length of the year to be 365 days and 6 hours, or a quarter of a day. From this it followed that the reckoning of the civil year began too soon. i. e. six hours before the sun had reached the point whence it started its annual cycle. In four years, therefore, the year would begin an entire day too soon. To remedy this Caesar instituted leap-years, a 366th day being introduced in every fourth year, to cover the fractional portions of a day thus accumu- lated. This extra day was assigned to February, the 24th and 25th day of which were styled in leap-year the sixth before the calends (or first) of March. Hence the name Bissextile given to these years.
Caesar's reform, which was introduced in the year 46 B.C., would have been perfect had the calculation on which it was based been accurate. In reality, however, the portion of a day to be dealt with, over and above the complete 365, is not quite six hours, but 11 minutes and 14 seconds less. To add a day every fourth year was, therefore, almost three quar- ters of an hour too much, the following new year com- mencing 44 minutes and 52 seconds after the sun had passed the equinox. At the end of a century these accumulated errors amounted to about three-quarters of a day, and at the end of four centuries to three entire days. The practical inconveniences of this de- fect in the system were not slow in making themselves felt, the more so as, Caesar being murdered soon after (44 B.C.), leap-year, by a misunderstanding of his plan, occurred even - third year, instead of every fourth. At the time of the Julian reform the sun passed the vernal equinox on 25 March, but by the time of the Council of Nicsea (a.d. 325) this had been changed for the 21st, which was then fixed upon as the proper date of the equinox — a date of great importance for the calculation of Easter, and therefore of all the moveable feasts throughout the year.
But the error, of course, continued to operate and disturb such arrangements. In the thirteenth cen- tury the year was seven days behind the Nicaean computation. By the sixteenth it was ten days in arrear, so that the vernal equinox fell on 11 March, and the autumnal on 11 September; the shortest day was U December, and the longest 11 June, the feast of St. Barnabas, whence the old rhyme: —
Barnaby bright, the longest day and the shortest night.
