HEGIRA

In Chronology, the era used by the Mohammedans in the computation of time. The epoch or first day of this celebrated era, so extensively employed in the East, corresponds to Friday the 16th day of July in the year 622 of the Christian era. It is a problem of some importance to convert dates expre ed by the Mohammedan computation into the corresponding dates of our calendar; for effecting this it is nece ary to be acquainted with the form of the Mohammedan year. This year is strictly lunar; and the civil months are adjusted to the lunar months by means of a cycle of 30 years, containing 19 common years of 354 days, and 11 intercalary years of 355 days; the cycle thus containing 10,631 days, or 29 Julian years and 39 days. Each year IS divided into 12 months, containing alternately 30 and 29 days, excepting that the last month of the intercalary year contains also 30 days. The intercalary years are the 2d, 5th, 7th, 10th, 13th, 16th, 18th, 21st, 24th, 26th, and 29th of the cycle. The names of the Mohammedan months, with the number of days in each, are as follow: — Moharem -^o'Shaban - IW Saphar - 29 Ramadan - - 30 Rabiu I. - 30 Shaw all - -29 Rabiu 11. - 29 Dhu'l Kadah - - 30 Jomadhi I - 30 Dhu'l Hajah - - 29 Jomadhi II. - 29 Regeb - 30 calary years - - 30 Such are the chronological elements by means of which Mohammedan dates are reduced to the Christian era. The rule by which the reduction may be accomplished is as follows: _ 1. Divide the number of years (of the Hegira) elapsed by 30; the quotient will be the number of cycles, and the remainder the number of years elapsed since the beginning of the current cycle. Call the quotient A, and the remainder B, and let x be the number of intercalary years 545 HEIGHTS. in B; then the number of days that have elapsed from the commencement of the Hegira to the beginning of the year in which the date occurs is given by this formula, 10631 A -h 354 B + *y for 10,631 is the number of days in the cycle, and 354 the number of days in the common lunar year. To the sum obtained by this formula add the days since the beginning of the current year, and the result is the number of days from the commencement of the Hegira to the given date. 2. To the number of days from the commencement of the Hegira to the given date add the number of days between the commencement of our era and the Hegira, and the sum is the number of days from the first of our era to the given date. The number of days from the beginning of our era to the Hegira, or to the I6th of July, 622, is 227,016. 3. Having now found the number of days from the Incarnation to the given date, it only remains to convert the sum into Julian years. For this purpose divide bj 1461 (the number of days in the Julian intercalary period), and call the quotient C. Divide the remainder by 365, and call the quotient D, and the remainder of this last division y. Then 4 C -|- D is the number of Julian years elapsed since the beginning of the Christian era, and y is the number of days that have elapsed of the current year. This gives the date in Old Style. To reduce it to the Greg or i an Style, it is only nece ary to add 11 days. (See art. " Chronology," in the Encyclopedia Britannica.) [s. 558]