158 
MAGNETIC OBSERVATIONS. 
OBSERVATIONS—Continued. 
Station, Cambridge Observatory; latitude 42° 22' 48"; longitude 4 h. 44 m. 29.6s. 
Needle, B. Dale, May 10, 1854. Hour of beginning, 12 h. 30 m. p. m. ; hour of ending, 1 h. p. m. 
Observers, Prof. W. C. Bond and Lieut. J. C. Ives. 
o ' " 
( 14 48 
Needle vertical, face of circle north, reading of azimuth circle_ J 14 48 
( 14 55 
( 14 47 
Needle vertical, face of circle south, reading of azimuth circle... J 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. 3. 
Face of circle. 
East. 
West. 
Means. 
Corr. for index error of needle 
Deduced inclination. 
Sum of means. 
Half sum = dip . 
Diff. of means. 
Direct. 
Half diff. — angles of deflection. 
o < 
74 28 
74 25 
74 21 
74 22 
74 28 
74 25 
o ' " 
74 24 50 
4- 8 48 
o ' " 
74 33 38 
Def. S. atapp. dip. 74° 24' 50". 
Def. N. atapp. dip. 74° 24'50. 
Def. towards 
the vertical. 
o ' 
106 55 
106 50 
106 55 
106 40 
106 48 
106 45 
Def. from the Ther. Def. towards 
the vertical. Fall. the vertical. 
o » o 
41 65 70 
41 70 . 
41 60 ;_ 
41 40 . 
41 45 . 
41 50 70 
106 48 50 
41 55 00 
70 
o ' 
104 45 
104 50 
104 55 
104 45 
104 48 
104 50 
Def. from the 
the vertical. 
o 
43 50 
43 50 
43 45 
43 55 
43 55 
43 50 
104 48 50 
43 50 50 
o < « 
148 43 50 
74 21 55 
64 53 50 
32 26 55 
148 39 40 
G 4 ft 
74 19 50 
60 58 00 
30 29 00 
Ther. 
Fah. 
o 
70 
70 
o 
70 
