590 
MR. A. W. RUCKER AKD DR. T. E. THORPE ON A MAGNETIC 
Local and Regional Disturbing Forces obtained from the Two Surveys 
Separately and Combined. 
The magnitudes and directions of the Horizontal Disturbing Forces and the 
magnitudes of the Vertical Disturbing Forces were calculated for all the stations 
twice over. 
(1) For stations at which observations were made in 1884-88, using the terrestrial 
lines deduced from the 1886 Survey. 
(2) For stations at which observations were made in 1889-92, using the terrestrial 
lines deduced from the 1891 Survey. 
(3) For all the stations, using the mean terrestrial lines deduced from both 
Surveys. 
As has been already stated, the first two sets of results are entered in columns 4 
to 6 of the following tables, the thii-d set in columns 7 to 9. 
F^ and F are the magnitudes of the Horizontal Disturbing Forces. 
(j)i and (f) the angles which their directions make with the north point on the 
geographical meridian, taken as positive when measured from north to west. 
Z| and Z are the Vertical Disturbing Forces taken as positive when a north pole 
is urged downwards. 
The Disturbing Forces have been recalculated for a number of the 1886 Survey 
stations and a few arithmetical errors detected. 
Both the Horizontal and Vertical Disturbing Forces are expressed in terms of 
O’OOOl metric, or O'OOOOl C.G.S. unit. 
Table XXV.—Table of Disturbing Forces. 
Scotland. 
No. No. 
1891. 1886. 
Station. 
V- 
01- 
Zi. 
F. 
- 9>- 
Z. 
1 
1 
1 1 
Aberdeen (1) • 
Between— 
82 
-14°4 
- 28 
103 
-150 
— 77 
2 
Aberdeen and Ellon 
(D 
224 
-139 
-176 
199 
-135 
-121 ^ 
3 
(3) 
382 
-139 
+ 11 
357 
-136 
+ 67 1 
4 
(4) 
142 
- 26 
-214 
166 
- 20 
-159 1 
Between — 
I 
5 ' 
Aberdeen and Stoneliaven 
Co) 
167 
-149 
- 52 
140 
-145 
- / 
6 
>5 M 
(6) 
79 
+ 87 
+ 210 
92 
+ 70 
+ 259 
7 
(D 
123 
-161 
-174 
96 
-159 
-127 
8 
Abington 
40 
+ 4 
-125 
52 
+ 6 
—105 j 
9 
Aboyne .... 
410 
+166 
- 90 
388 
+ 164 
- 59 
10 
Achanalt . 
63 
- 99 
-190 
58 
- 90 
-180 
11 
Acbnasbellach 
82 
-150 
-2.51 
73 
-1-50 
-247 
12 ' 
Alford .... 
34 
+ 165 
o 
— o 
17 
+ 123 
+ 37 
13 1 
Altnabreac. . . 
73 
+ 178 
-212 
63 
+ 176 
-169 
14 ■ 
Altuabarra. 
108 
- 19 
-330 
115 
- 17 
-296 
