392 DR. C. CHREE: ANALYSIS OF RESULTS FROM THE KEW MAGNETOGRAPHS 
Table XXVI.—Relations between Fourier Coefficients in mean Diurnal Inequality 
for the Year. 
C 2 /C 1 . 
C3/C1. 
C 4 /C 1 . 
Declination. 
(11 years) 
•77 
•38 
•12 ' 
, ^ ! 
Westerly component. 
V 
•78 
•43 
•15 1 
Horizontal force. 
35 
•54 
•25 
•14 1 
Northerly com23onent. 
33 
•58 
•19 
•09 ; 
Inclination. 
(10 years) 
•49 
•30 
•17 
Vertical force. 
•75 
•33 
•11 
Total force. 
•65 
•25 
•08 
i 
Table XXVII.—Relation between Fourier Coefficients in Diurnal Inequalities for the 
Seasons (from 11 or 10 years at Kew). 
Col Cl- 
Csici. 
1 
CilCi. 
Winter. 
Equinox. 
Summer. 
Winter. 
Equinox. 
Summer. 
Winter. 
Equinox. 
Summer.. 
1 
1 
Declination . 
•65 
•81 
•78 
•36 
•47 
•32 
•18 
•19 
•04 
Inclination 
•92 
•48 
•40 
•43 
•35 
•17 
•32 
•21 
•09 
Horizontal force . 
1-07 
•54 
•42 
•50 
•30 
•16 
•31 
•17 
•06 
Vertical force. . 
•68 
•76 
•75 
•35 
•41 
■26 
•17 
•15 
•06 
§ 35. Taking the 24-hour term, we see in D, I, H and V (see Tables XX. to XXIII.) 
a fairly regular annual variation of considerable amplitude in the angle In D 
and V, is larger in winter than in summer; in I and H it is the other way 
about. A larger value of means an earlier hour for the occurrence of the 
maximum, an increase of 15° representing an advance of one hour. The angle aj 
increases fairly regularly in passing from winter to summer in the case of D, I and 
H ; but in V the winter value is the largest. The angles and oc^ show a fairly 
regular increase from winter to summer in I and H, but in D and V the annual 
variation seems small. 
§ 36. Table XXVIII. gives an analysis of the values of a for the seasonal 
inequalities when local solar time is used; the corresponding hours of occurrence 
of the first maximum of the day are sho^vn in Table XXIX. The hours are counted 
from 0 to 24, with 0 representing true local midnight. The table goes only to 
tenths of hours, but suffices to show the much greater variability in the time of 
occurrence of the maximum of the 24-hour wave than in the maxima of the waves 
of shorter periods. The variability appears greater in I and H than in D or V. 
