160 
MAGNETIC OBSERVATIONS, 
OBSERVATIONS—Continued. 
Station, Cambridge Observatory; latitude 42° 22' 48"; longitude &h. 44 m. 29.6s. 
Needle, A. Date, May 10, 1854. Hour of beginning, 1 h. 50 m. p. m.; hour of ending, 2h. 10m. p. m. 
Obseimers, 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 
C 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. 4. 
Face of circle. 
East. 
West. 
Means. 
Corr. for index error of needle.. 
Deduced inclination_ 
Differences.. 
Half diff. or angles of deflection.. 
Sum of means.. 
Direct. 
o ' 
74 35 
74 35 
74 30 
74 30 
74 28 
74 25 
74 30 30 
4- 15 04 
74 45 34 
Half sum = dip . 
Def. with w r t. 2 \ gr. 
Def. towards 
the vertical. 
( 1 ) 
o / 
104 38 
104 40 
104 45 
104 35 
104 25 
104 20 
Def. from 
the vertical. 
( 2 ) 
o i 
43 45 
43 45 
43 50 
43 45 
43 45 
43 55 
( (1) 104 33 50 ) 
I (2) 43 47 30 j 
60 46 20 
30 23 10 
148 21 20 
74 10 40 
Ther. 
Fah. 
o 
72 
72 
® 
72 
Def. with wt. 3 gr. 
Def. towards 
the vertical. 
(1) 
Def. from 
the vertical. 
(2) 
i 
O ' 
111 35 
111 30 
111 37 
111 18 
111 30 
111 20 
O ' 
36 45 
36 40 
36 50 
36 55 
36 45 
36 52 
O ' " 
j (1) 111 28 20 ) 
j (2) 36 47 50 j 
74 40 30 
37 20 15 
148 16 10 
74 08 05 
Ther. 
Fah. 
72 
72 
. o 
72 
Station, Cambridge Observatory. Dale, May 10, 1854. 
Reading of azimuth circle when plane of instrument is in the true meridian_•_ 
Face west.... 
Face east .... 
o ' 
5 07 
5 01 
Mean 
5 04 
