222 
MU. A. W. RUCKER AND DR. T. E. THORPE ON A MAGNETIC 
Inclination. 
Needle. 
G.M.T. 
0. 
00- 
1 
2 
h. ni. 
11 52 
12 16 
6°8 46-2 
68 45-6 
o t 
68 48-6 
IIorizo7ital Force. 
G.M.T. 
H. 
Ho. 
D 
h. m. 
12 52 
1-7463 
1-7427 
V 
10 49 
1-7455 
188. Londonderry. August 20, 1887 ; T. E. T. (61, 83). Lat. 55° 1' 24"; Long. 
7° 18' 6". In a field adjoining the Moville Road, about 2 miles from Derry, and 
between the Road and the Lough. Boom Hall Lodge Gate 70° E. of N. ; 
distant 50 yards. Boom Hall 35° W. of S. ; distant 400 yards. 
Declination. 
G.M.T. 
0. 
5o. 
li. m. 
- 0 25 
+ 1 ^2 
li. m. 
12 .52 
14 13 
22 35-5 
22 38-7 
o t 
22 50-5 
Inclination. 
Needle. 
G.M.T. 
0 . 
00. 
h. m. 
o / 
o / 
1 
15 
28 
70 24-6 
70 26-9 
2 
15 
56 
70 24-2 
Horizontal Force. 
G.M.T. 
11. 
Ho- 
h. 
in. 
D 
16 
21 
1-6368 
1-6365 
1-6333 
V 
V 
13 
13 
22 
49 
1-6376 
1-6367 
1-6338 
