106 



G. H. KNIBBS. 



"movable feast" Easter. As ecclesiastically defined 

 Easter day is the first Sunday after the 14th day of the 

 paschal " Calendar Moon," a fictitious ecclesiastical moon, 

 which is from one to three days later than the real moon 

 (See De Morgan's article in the Companion to the Almanac 

 1845). The average position of Easter for the century 1800 

 to 1899 is April 8*55 days, and for the century 1900 to 1999 

 is April 8*89 days, or say for the whole period of 200 years 

 April 8*72 days. In the illustrative figure herewith, the 

 whole of the Easters in each decade are shewn on a single 

 line for the years 1800 to 1999 inclusive. It will be seen 

 that an inspection of the diagram will disclose the fact 

 that the points lie approximately on a series of 10 slanting 

 lines, four days apart, these lines progressing at the rate 

 of one half day per decade, and further that they are 

 inversely symmetrical. For lines a, b, c, and e and a , b\ 

 c', and e the symmetry is perfect ; for lines d and d' however 

 the symmetry is not absolutely perfect. It is evident that 

 no means derived from two decades nor from periods of 19 

 years, nor from centuries are exactly comparable. 



Position of Easter. 



March 



22 23 24 25 2G 27 28 23 30 31 1 2 3 4 5 6 7 



April 



l 9 10 II 12 13 14 15 IG 17 18 19 20 21 22 23 2425 



— 1' 1 \ S j ! t ~*~ it ~" t I 



— " 1 I1T — ^° ^~~ 



n' * aft tt ii" 



X '\! i IV n\. u > 



M 1 ^i t ,\, u x 



v ^ i i ii (» ii <L T ii- 





<\l \ '\" <* >\ 



► ' 1 Ji fS, n X '^O 





* Vb i i,' N.a Ni 



\\ n\i n'n \, i 



ir 7 v "\ ''<? '( N 



\j\ " ' . " >\ '' x ■ 



V «• ii ^ ^ x 



iS \ 1^ "\ 



i T'\ v x \ 



r *v ^btC-^^r '^^~ 



— «e — ^ — **-*$- — -^ 



V— V — *rr = -V— ^ 



5-5^ s s ^ r . 





1 | .11 ,r U 1^ 



\ '\t v ° "^ * 



1 II (Ml II \ 



\ *X i\ \>v 



3ljz ~^_ ^.v "3- X 



. %P %>- -Z ^zz 





^S> ii \ \i 



"_v " H ^_ _^ "V : 







^^ _}l Ji,_ — <^>- 



v ), \ ^, (l , 



:^±^-^ J!^-_J^ ^.t 



-^ ' ' :^l ^ j - 



1800-3 

 10-19 

 20-23 

 30-39 

 40-43 

 50-53 

 GO-69 

 70-73 

 80-89 

 30-99 



1300- 3 

 1013 

 20-23 

 30-33 

 40-43 

 50-59 

 60-63 

 70-7? 

 80-83 

 30-39 



