MAGNETIC OBSERVATIONS. 
157 
OBSERVATIONS—Continued. 
Station, Cambridge Observatory ; latitude 42° 22' 48"; longitude 47?.. 44m. 29.6s. 
Needle, B. Nate, May 10, 1854. Hour of beginning, 1 h. p. m. ; hour of ending, \h. 20m. p. m. 
Observers, Prof. W. C. Bond and Lieut. J. C. Ives. 
o ' " 
f 14 48 
Needle vertical, face of circle north, reading of azimuth circle.-.-.7 14 48 
( 14 55 
f 14 47 
Needle vertical, face of circle south, reading of azimuth circle... 1 14 52 
( 14 46 
Reading of azimuth circle when plane of instrument is in the magnetic meridian.. 14 49 20 
Reading of azimuth circle when plane of instrument is in the true meridian... 5 04 00 
Approximate magnetic declination......... 9 45 20 W. 
OBSERVATIONS FOR MAGNETIC INCLINATION AND INTENSITY—No. 4. 
Face of circle. 
Direct. 
Def. with wt. 2 J gr. 
Def. towards 
the vertical. 
(1) 
Def. from 
the vertical. 
(2) 
Ther. 
Fah. 
Def. with wt. 3 gr. 
Def. towards 
the vertical. 
( 1 ) 
Def. from 
the vertical 
( 2 ) 
Ther. 
Fah. 
East. 
West. 
74 28 
74 25 
74 21 
74 22 
74 28 
74 25 
Means___ 74 24 50 
Cor. for index error of needle_! -f- 8 48 
Deduced inclination. 
Differences. 
O'" 
74 33 38 
Half diff. or angles of deflection. . 
Sum of means 
104 40 
104 45 
104 50 
104 45 
104 40 
104 42 
43 40 
43 45 
43 45 
43 50 
43 55 
43 50 
o 
70 
o ' 
111 40 
111 
111 
35 
33 
111 55 
70 
111 
111 
50 
50 
o ' 
36 32 
36 35 
36 30 
36 35 
36 32 
36 30 
(1) 104 43 40 
(2) 43 47 30 
70 
j (1) 111 43 50 ) 
j (2) 36 32 20 j 
o / " 
60 56 10 
30 28 05 
o > " 
148 31 10 
75 11 30 
37 35 45 
148 16 10 
74 15 35 
74 08 05 
o 
70 
70 
o 
70 
Half sum = dip 
