156 
MAGNETIC OBSERVATIONS, 
OBSERVATIONS—Continued. 
Station, Cambridge Observatory ; latitude 42° 22' 48" ; longitude 4A. 44m. 29. 6s. 
Needle, A. Date, May 10, 1854. Hour of beginning, 12/i. m. ; hour of ending, 12 h. 30 m. p. m. 
Observers, Prof. W. C. Bond and Lieut. J. C. Ives. 
o ' " 
( 14 52 
Needle vertical, face of circle north, reading of azimuth circle... } 14 50 
( 14 45 
( 14 52 
Needle vertical, face of circle south, reading of azimuth circle_ 14 50 
( 14 60 
Reading of azimuth circle when plane of instrument is in the magnetic meridian_ 14 51 30 
Reading of azimuth circle when plane of instrument is in the true meridian..... 5 04 00 
Approximate magnetic declination ______-.- 9 47 30 W. 
OBSERVATIONS FOR MAGNETIC INCLINATION AND INTENSITY—No. 2. 
Face of circle. 
East. 
West.. 
Means.. 
Sum of means. 
Half sum — dip . 
Differences. 
Direct. 
o ' 
74 35 
74 35 
74 30 
74 30 
74 28 
74 25 
O ' n 
74 30 30 
N. P. needle B 40° 
from dip. 
o < 
at 34 25 
Half diff. = angles of dcllcction- 
o ' 
96 50 
96 48 
96 58 
at 114 25 
o ' 
51 45 
51 48 
51 45 
96 25 51 50 
96 25 i 51 50 
96 20 51 48 
S. 
P. needle B 40° 
from dip. 
at 34 25 
94 50 
94 48 
94 55 
94 38 
94 40 
94 50 
at 114 25 
o ' 
53 45 
53 40 
53 40 
53 50 
53 40 
53 40 
( 96 
37 
40 
j 
94 
46 
50 
\ 51 
~rT 
40 
1 
53 
42 
30 
o 
1 
„ 
o 
/ 
„ 
148 
25 
20 
148 
29 
20 
o 
/ 
„ 
o 
/ 
// 
74 
12 
40 
74 
14 
40 
o 
, 
„ 
o 
/ 
// 
44 
57 
00 
41 
04 
20 
o 
t 
n 
0 
/ 
// 
22 
28 
30 
20 
32 
10 
Results. 
O 
/ 
// 
74 
30 
30 
N. 
74 
12 
40 
S. 
74 
14 
40 
74 19 17 
+ 15 04 
o / r 
74 34 21 
Direct. 
deflectors. 
[By 
Mean. 
l] 
1 I” 
Index error. 
True inclination. 
