EARTH’S MAGNETISM AT PAVLOVSK AND POLA (1897-1903). 
315 
Table V.—Probable Errors of the Mean Values of a n and b n in Tables II.-IV. # 
The results are in every case reduced to force, the unit being 10 -7 C.G.S. 
1 
Observatory and 
element. 
Season. 
«i- 
h. 
a- 2 . 
b 2 . 
ao. 
^3- 
a 4 . 
64 . 
Pola. 
Horizontal force * 
Summer. 
Equinox. 
Winter. 
13 
10 
19 
14 
12 
8 
10 
7 
8 
8 
4 
6 
7 
4 
3 
3 
4 
6 
6 
2 
4 
3 
6 
4 
Pavlovsk. 
Horizontal force 
' 
Summer. 
Equinox. 
Winter. 
8 
16 
15 
11 
7 
7 
5 
9 
6 
8 
11 
6 
5 
6 
6 
5 
6 
3 
5 
5 
5 
2 
4 
2 
Pola. 
Transverse force 
' 
Summer. 
Equinox. 
Winter. 
11 
7 
9 
10 
7 
6 
7 
9 
6 
5 
8 
8 
2 
6 
4 
6 
8 
5 
3 
6 
5 
4 
4 
4 
Pavlovsk. 
Transverse force * 
Summer. 
Equinox. 
Winter. 
13 
15 
8 
12 
15 
9 
13 
15 
5 
9 
10 
7 
6 
5 
7 
6 
6 
4 
4 
6 
3 
3 
4 
6 
Pola. 
Vertical force * 
Summer. 
Equinox. 
Winter. 
8 
13 
7 
5 
10 
10 
1 
6 
4 
4 
5 
5 
2 
4 
2 
3 
3 
2 
2 
4 
2 
2 
1 
3 
Pavlovsk. 
Vertical force 
' 
Summer. 
Equinox. 
Winter. 
13 9 
14 12 
8 11 
3 
4 
3 
5 
4 
6 
3 
3 
3 
1 
3 
3 
2 
2 
2 
3 
1 
1 
1 
* Of. § 10 . 
2 S 2 
