382 r>E. C. CHKEE: ANALYSIS OF RESULTS FROM THE KELT MAGNETOGRAPHS 
Table XIX.—Corrections to be applied to Angles in Fourier Expansions when 
G.M.T. replaced by Kew Solar Time. 
Angle .... 
ai. 
^3- 
a-i. 
January . 
o 
+ 2 
42 
+ 5 
24 
-r 
o 
8 
6 
4- 
lb 
48 
February. 
+ 3 
48 
+ 7 
36 
+ 
11 
24 
4- 
15 
12 
March. 
-t-2 
28 
+ 4 
56 
■I" 
7 
24 
4- 
9 
52 i 
April. 
+ 0 
20 
+ 0 
40 
-t- 
1 
0 
4- 
1 
20 : 
May. 
-0 
33 
- 1 
6 
- 
1 
39 
- 
2 
12 
June. 
-rO 
25 
+ 0 
50 
4- 
1 
15 
4- 
1 
40 
Julv ... ... 
+ 1 
41 
+ 3 
22 
-f 
5 
3 
4- 
6 
44 . 
August. 
+ 1 
15 
+ 2 
30 
3 
45 
4- 
5 
0 
September .... 
-0 
58 
- 1 
56 
- 
2 
54 
- 
3 
52 
October. 
-3 
12 
-6 
24 
- 
9 
36 
- 
12 
48 
November. 
-3 
20 
-6 
40 
- 
10 
0 
- 
13 
20 
December. 
-0 
40 
- 1 
20 
— 
2 
0 
2 
40 : 
1 
Year. 
+ 0 
19 
+ 0 
38 
4- 
0 
57 
4- 
1 
16 
Winter. 
+ 0 
37 
+ 1 
14 
4- 
1 
51 
4- 
2 
28 
Equinox. 
-0 
21 
-0 
42 
- 
1 
3 
- 
1 
24 
Summer. 
+ 0 
42 
+ 1 
24 
4- 
2 
6 
4- 
2 
48 
§ 32. Tables XX. to XXIII. give the values of the two sets of Fourier constants 
a, h, and (\ a —using G.M.T. —for D, I, H, and Y. Values are given for the 
inequalities for the several months, for the year as a whole, and for winter, equinox, 
and summer, each representing, as before, a group of 4 months. 
The D and H results are Imsed on the 11 years 1890 to 1900, the I and Y results 
on the 10 years 1891 to 1900. 
An a or h coefficient for a group of i months is the arithmetic mean of the ci’s or Us 
for the individual i months ; but this is not in general true of the c’s or a’s. For 
instance, the arithmetic meai' of the 12 values of Cj for individual months of the year, 
in Table XX. is 2-371, the mean of the three values for cq for the three seasons 
is 2-356, whilst the value of cq from the mean inequality for the year is 2-322. The 
more variable the angle a throughout the season dealt with, the greater is the 
difference Ijetween the corresponding e for that season and the arithmetic mean of the 
c’s for the individual months comiDosing it. 
In all probability it would require a very large number of years’ data to supply 
smooth values for the coefficients of the 8-hour and 6-hour terms, and much weight 
cannot be assigned to apparent irregular fluctuations in the values of these coefficients 
from month to month. This is really one of the principal reasons for grouping the 
months into seasons. The four mid-winter months stand out rather noticeably from 
the tv-o adjacent months Mai'ch and October, so that separatipn into three seasons 
seems better for the })resent purpose than the more usual separation into two 6-montb 
periods. 
