154 



E. WALTER MAUNDER, ESQ., F.R.A.S., ON 



moment, but they might be fixed in advance,, and Hillel II 

 (in A.D. 358) is reputed to have published the rules, previously 

 kept secret, by vvhich the calendar had been calculated and the 

 festivals appointed. 



The present Jewish calendar is computed on the same general 

 lines as Easter in the Gregorian calendar : that is to say, advan- 

 tage is taken of the fact that 19 mean solar years contain 6939 

 days 14J hours, and 235 mean synodic months contain 6939 

 days 16| hours, the two therefore differing only by a couple of 

 hours. The discovery of this cycle is attributed to Meton — 

 about 433 B.C. — and it is therefore known as the Metonic cycle. 

 It supplies the " golden numbers " of the " Introduction to the 

 Book of Common Prayer." 



As the moon in its motion round the earth varies a good deal 

 in its angular velocity, the movements of a mean moon, trav(?lling 

 uniformly, are substituted for those of the actual moon, and the 

 month is taken as beginnmg with the conjunction of this mean 

 moon with the sun. It follows, therefore, that the beginnings of 

 the Jewish months can be rigidly computed for a long time in 

 advance without any ambiguity or discordance arising from the 

 latitude and longitude of the special place to which the calendar 

 is to be applied. Like our computations for Easter, it is intended 

 for universal application, not merely local. 



This great difference between the Mosaic Calendar and the 

 modern Jewish calendar was necessary and fundamental. When 

 the nation was in the land which the Lord their God had given 

 them, then the determination of the new moon and of the 

 emboHsmic month could be made directly, could be adopted 

 by one single authority, and made known to the whole nation 

 immediately. Now, when the Jews are scattered over the whole 

 world, the only possible method by which perfect unanimity 

 in the decision as to sacred days can be attained is by fixing 

 them by computations based on a definite plan, and made long in 

 advance. 



The cycle adopted for the present Jewish calendar is not the 

 Jubilee cycle, but the Metonic. The practical difference between 

 the two, in pointing out when a month was to be intercalated, 

 may be seen from the following table. The embolismic years,, 

 according to the Metonic cycle, are generally given as under : — 



3 6 8 11 14 17 19 

 The order is then repeated. 



