106 
DR. S. CHAPMAN ON THE SOLAR AND LUNAR 
Table IY. (l) (c).—Fourier Coefficients of the Lunar Diurnal Magnetic Variation. 
Reduced to the Epoch of New Moon. 
(1) Zi-Ka-Wei. 
(c) Vertical Force (Upwards). 
Season. 
' Summer . 
Equinox 
Winter 
Lunar 
phase. 
a\. 
b\. 
bo. 
b 3- 
a' 4 . 
b\. 
1 
41 
- 39 
87 
15 
-34 
-45 
- 18 
- 9 
2 
15 
92 
130 
— 29 
12 
-62 
13 
-24 
3 
47 
37 
116 
- i 
14 
-29 
8 
1 
4 
65 
- 58 
112 
36 
2 
- 35 
15 
-22 
5 
- 12 
- 27 
80 
11 
o 
— 0 
- 17 
- 4 
6 
6 
41 
- 41 
125 
38 
14 
-28 
30 
- 16 
7 
- 5 
20 
118 
- 4 
14 
-48 
- 8 
- 17 
8 
11 
- 56 
119 
6 
-37 
-26 
-21 • 
- 3 
Mean. . 
26 
- 41 
111 
4 
_ 2 
-36 
2 
- 11 
1 
14 
23 
98 
28 
- 5 
- 4 
- 6 
3 
2 
58 
30 
94 
51 
— 2 
- 10 
- 7 
6 
3 
28 
- 12 
119 
31 
i 
-20 
- 12 
- 17 
.4 
-65 
108 
110 
34 
34 
1 
-29 
7 
5 
32 
- 160 
190 
135 
- 1 
-70 
38 
40 
6 
65 
42 
141 
6 
15 
- 11 
19 
— 25 
7 
32 
- 21 
99 
- 11 
-19 
-37 
4 
- 14 
s 
19 
• 35 
127 
9 
6 
- 18 
- 6 
1 
Mean. . 
23 
3 
122 
25 
4 
-21 
0 
_ 2 
1 
-59 
33 
42 
8 
-26 
- 6 
- 8 
- 17 
2 
-60 
■ 68 
43 
- 23 
7 
-34 
23 
- 10 
3 
52 
- 33 
85 
76 
-24 
14 
- 10 
- 14 
4 
-98 
65 
65 
- 47 
43 
9 
-27 
8 
5 
20 
56 
133 
32 
12 
- 10 
16 
-13 
6 
51 
92 
50 
2 
- 10 
- 8 
- 5 
1 
7 
-39 
- 52 
110 
36 
- 3 
-21 
- 4 
- 6 
8 
-89 
- 8 
114 
64 
28 
4 
20 
-34 
Mean. . 
- 28 
34 
80 
18 
4 
- 7 
0 
-11 
