To find, as a test, the accurate day of the week, the proposed year of the Hegira, divided by 30, gives 45 cycles, and remainder 12, the year of the current cycle.
Also 45, divided by 7, leaves a remainder 3 for the number of the period.
Therefore, referring to 3 at the top of the table, and 12 on the left, the required day is Friday.
The tables, page 571, show that 8th January 1943 is a Friday, therefore the date is exact.
For any other date of the Mahommedan year it is only requisite to know the names of the consecutive months, and the number of days in each; these are—
| Muharram | 30 |
| Saphar | 29 |
| Rabia I. | 30 |
| Rabia II. | 29 |
| Jomada I. | 30 |
| Jomada II | 29 |
| Rajab | 30 |
| Shaaban | 29 |
| Ramadān | 30 |
| Shawall (Shawwāl) | 29 |
| Dulkaada (Dhu'l Qa'da) | 30 |
| Dulheggia (Dhu'l Hijja) | 29 |
| - and in intercalary years | 30 |
The ninth month, Ramadān, is the month of Abstinence observed by the Moslems.
The Moslem calendar may evidently be carried on indefinitely by successive addition, observing only to allow for the additional day that occurs in the bissextile and intercalary years; but for any remote date the computation according to the preceding rules will be most efficient, and such computation may be usefully employed as a check on the accuracy of any considerable extension of the calendar by induction alone.
The following table, taken from Woolhouse's Measures, Weights and Moneys of all Nations, shows the dates of commencement of Mahommedan years from 1845 up to 2047, or from the 43rd to the 49th cycle inclusive, which form the whole of the seventh period of seven cycles. Throughout the next period of seven cycles, and all other like periods, the days of the week will recur in exactly the same order. All the tables of this kind previously published, which extend beyond the year 1900 of the Christian era, are erroneous, not excepting the celebrated French work, L'Art de vérifier les dates, so justly regarded as the greatest authority in chronological matters. The errors have probably arisen from a continued excess of 10 in the discrimination of the intercalary years.
Table IX.—Mahommedan Years.