316 
DR. S. CHAPMAN ON THE LUNAR DIURNAL VARIATION OF THE 
Table YIa. —Fourier Coefficients of the Lunar Diurnal Variations of the Geographical 
Components of Magnetic Force at Pavlovsk and Pola, # in the Formula 
2C n sin (nt + d n ). 
The time t = 0 is the local time of upper culmination of the moon at the phase of 
new moon. The unit of force is 1 (V 7 C.G.S. ; + denotes an increase of force to 
the North, West, or to the Nadir. 
North force. 
West force. 
Vertical force. 
n. 
Pavlovsk. 
Pola. 
Pavlovsk. 
Pola. 
Pavlovsk. 
Pola. 
c n . 
On- 
C n . 
On- 
C n . 
0 n - 
C n . 
0 n . 
C n . 
0 n - 
Cn. 
0 n - 
Sunn 
ner. 
i 
61 
o 
23 • 8 
Ill 
14-5 
131 
o 
117-9 
113 
o 
125-8 
36 
329-5 
15 
O 
308-1 
2 
105 
8-3 
133 
27 - 2 
128 
92-7 
161 
79-9 
13 
27-1 
62 
311-4 
3 
62 
- 0-9 
86 
43-3 
28 
87-3 
80 
88-2 
11 
106-6 
30 
313-3 
4 
26 
295-2 
20 
47-5 
2 
— 
- 4f 
(91) 
1 
— 
5o 
(308) 
Equinox. 
1 
42 
o 
- 11-2 
63 
o 
4-6 
79 
o 
120-7 
71 
o 
126-2 
13 
o 
230-5 
14 
278-7 
2 
48 
3-1 
80 
31-0 
82 
88-0 
60 
62-1 
17 
199-0 
24 
346-5 
3 
63 
5-4 
71 
39-3 
13 
100-3 
48 
102-3 
2 
— 
14 
348-1 
4 
27 
- 18-2 
21 
54-9 
15 
119-6 
26 
109-2 
- 5t 
(233) 
14 
352-8 
Winter. 
1 
17 
o 
176-6 
50 
145-8 
28 
o 
218-0 
46 
220-5 
28 
o 
107-9 
15 
304-8 
2 
20 
250-2 
30 
127-8 
36 
313-8 
45 
322-2 
6 
341-0 
35 
300-4 
3 
20 
249-6 
11 
161-2 
21 
308-4 
15 
321-7 
2 
— 
7 
270-8 
4 
2 
— 
2 
— 
15f 
315-6 
3 
(351) 
4 
(231) 
1 
— 
* Cf.%11. 
t The coefficients C n of these components are reversed in sign in order to exhibit the accordance 
between the values of 0 n for different values of n. 
