Jan. 8, 1885] 



NATURE 



219 



In its later and more developed form this does not rest on 

 observation or on fluctuating astronomical calculations, 

 but on a comparatively simple cycle, based on a fixed 

 month and year. Everything is settled beforehand : the 

 intercalary month and year are inserted at stated periods. 

 The system is the nineteen-year metonic cycle : nineteen 

 solar years give 235 lunar months, in the course of which 

 the 3, 6, S, 11, 14, 17, and 19th years are intercalary, a 

 month being inserted between Adar and Nisan. The 

 months are successively 29 and 30 days long, the times of 

 each being settled. But simple as this appears, various 

 circumstances have conspired to render Jewish chronology 

 very complicated. Such are the inclusion of small frac- 

 tions of time in calculating the new moon for the new 

 year, and the frequent religious precepts dislocating the 

 arrangement for the beginning of the year ; so that there 

 are years of 353, 354, 355, as well as those of 383, 384, and 

 385 days. The years were reckoned regularly from the 

 creation of the world, which is placed on October 7, 

 3761 B.( . 



Having thus discussed the forms of the luni-solar year 

 still in existence, Dr. Schram refers to those formerly in 

 use by various nations. The Greeks also employed the 

 cycle of nineteen lunar years, with seven intercalary 

 months in every cycle, thus approximating to nineteen 

 solar years. The months were of 29 and 30 days, and the 

 years were reckoned by Olympiads of four years each. 

 Subsequently Calippus brought the metonic cycle closer 

 to solar periods by the omission of one day in every 76 

 years. 



Among many peoples the modes of reckoning time do 

 not deserve the name of a system. The Otaheitans used 

 the changes of the moon, and the growth of the bread- 

 fruit ; the Makha Indians on Cape Flattery the moon, 

 and the seasons, of which latter they distinguished two, 

 the cold and the warm ; the Muysca Indians, according 

 to Humboldt, had 37 lunar months in their cycle, and 20 

 of these cycles formed a larger one. Where there were 

 no religious festivals connected with the new or the full 

 moon, people gave up the luni-sOlar year altogether, and 

 adopted the solar year only, confining themselves to 

 bringing day and night into connection with it as far as 

 possible, and paying no regard to the moon's course. It 

 was soon found that the solar year was approximately 

 365 days in length, and this we find first in the year of 

 the ancient Egyptians. They divided their solar year of 

 365 days into 12 months, each of 30 days, to which they 

 added 5 supplementary days. The years were counted 

 according to the reigns, and the Canon of Ptolemy is a 

 chronological table giving the commencing years of the 

 various kings. The same form of year is found amongst 

 the Persians, with the difference that the supplementary 

 days were added to the 8th and not to the 12th month. 

 Their months had names, not numbers, and their years 

 were reckoned from the accession of Jezdegird, an era 

 from which the Persians, especially in some parts of India, 

 still count their years. It is remarkable that so inexa t a 

 year, originating so long ago, should have existed through 

 centuries down to our own day, although its incorrect- 

 ness was early recognised. The Egyptians, for whom the 

 time of the rising of the Nile, at the ascent of Sirius, was 

 of great importance, noticed soon that the occurrence 

 came later and later in their year, and that if the Dog-star 

 rose one year on New Year's Day, four years later it was 

 the second day, eight years the third, and so on. On this 

 they based the Sothis, or Dog-star period of 1461 I 

 years, in the course of which Sirius rose succe- 

 every day of the year. Then came the knowledge of the 

 yearof365-| days, which is tolerably exact, and of this 

 there are several forms of years. In Egypl the change 

 to the more exact reckoning was accomplished in a simple 

 way. The months of 30 days and their names were 

 retained, but to three of them in succession 5 days were 



added, and every fourth year the supplementary day gave 

 6 d tys to 1 month. This form of year is called the Alex- 

 andrian, and it is used at present by the Copts in con- 

 nection with the Diocletian era. This year of 365! days 

 was carried to Rome by Caesar, where the method of 

 counting time was in disorder ; and henceforth in Rome the 

 year was of this length, the months consisting of different 

 numbers of days, in place of the Alexandrian supplementary 

 days. This system forms the foundation of our calendar, 

 and is the well-known Julian reform. A peculiar form of 

 the year of 365 ] days was that of the ancient Mexicans. 

 Their solar year consisted of 18 months of 20 days each ; 

 at the end of the year 5 supplementary days were added, 

 and at the end of 52 years, 13 more days. The old 

 Icelandic year also was very peculiar. The unit there 

 was the week of 7 days, and in order to make the year an 

 exact number of weeks, there were 12 months of 30 days 

 each, with only 4 supplementary days at the end. Then 

 at the end of 6 or 7 years another week was added, so that 

 the ordinary year consisted of exactly 52 weeks, while the 

 leap year had just 53. The year of 365] days was, how- 

 ever, a little too long, and in about 128 years there was an 

 error of 1 day. In the Julian as well as in the Alexandrian 

 system an improvement was found. The former was re- 

 formed by Pope Gregory XIII., not so much in the form 

 of the year, as in the method of intercalating. In every 

 year divisible by 100 the intercalary day was to be 

 omitted ; but in those divisible by 400 it was to be intro- 

 duced. Shah Shelal Eddin reformed the Alexandrian 

 system by an ordinance that when the intercalation had 

 taken place every fourth year for 7 or 8 times, the next 

 time it should not take place till 5 years had elapsed. In 

 other words every seventh or eighth leap year was to be 

 the fifth, not the fourth year. Thus there would be 7 leap 

 years in 29, or 8 in 33 years. The last attempt to reform 

 the Alexandrian system was made during the French 

 Revolution, partly with the object of introducing the 

 decimal system into time reckoning, partly also to get 

 rid of all reference to Christianity or any other form of 

 confession. The year which was then introduced was 

 based on the Alexandrian year, but the intercalation was 

 different. The months, consisting of 30 days each, re- 

 ceived the names of Vendemiaire, Brumaire, Frimaire, 

 Nivose, &c, and were divided into 3 decades of 10 days 

 each, which took to some extent the places of the weeks. 

 The intercalation was not cyclical, but based on exact 

 astronomical calculations, and it was decreed that the 

 first Vendemiaire should commence with the day on 

 which, according to exact Paris time, the sun entered the 

 autumnal equinox. It is easy to see that this method of 

 intercalating could not exist long without reform, even if 

 there were no independent objections to it, for it has all 

 the defects of the Chinese year. The years were counted 

 from the proclamation of the Republic. 



The lunar year is the last portion of his subject treated 

 by Dr. Schram. All that can be said about it occupies 

 but a small space. Here a balancing of the days and of 

 the course of the moon alone is required, the movements 

 of the sun, and the change of the seasons being wholly 

 disregarded. The Tur c and Arabs use this year, and 

 indeed it is common all over the Mohammedan world. 

 The year has 12 lunar months ; but the Turkish year can 

 hardly be called a year in our sense •>( the term, with its 

 regular succession and return of the seasons. In the 

 course of 33 years the beginning of this year ranges over 

 the whole of the seasons. If a Turkish festival comes, 

 one year in the depth of winter, 16 years later it will be 

 at midsummer. The 12 months have 30 and 29 days : in 

 the leap year the last month has 30 instead of 29 days. 

 In a cycle of 30 years, the leap years are the 2nd, 5th, 

 10th, 13th, 15th, 18th, 21st, 24th,' 26th, and 29th years. 

 The years are counted from the flight of Mohammed from 

 Mecca to Medina. 



