12 



LUNAR EFFECT 



Expressed analytically, the lunar-diurnal variation in the two seasons is as 



follows : — 



In summer, 



A([ = — O'.OOG + 0'.028 sin (e + 18°) + 0'.2T8 (2s + G7°) 



In winter, 



A(L = +0'.005 + 0'.058 sin (9 + 264°) + 0M73 (29 + 115°) 



The characteristic feature of the annual inequality in the lunar-diurnal variation 

 is, therefore, a much smaller amplitude in winter than in summer. Kreil, indeed, 



LcNAR-DlUENAL VARIATION". 



In summer 



b 



M 



0h. 123456789 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24'>- 



r. c. l. C. U. C. 



Summer curve from 11,087 observations (.) 

 Winter " " 10,557 " (°) 



