MAGNETIC OBSERVATIONS. 
OBSERV ATIONS— Continued. 
Station, Cambridge Observatory ; latitude 420 22' 48" ; 
longitude 4h. 44m. 29.65. 
Needle, B. Date, May 10, 1854. Hour of beginning, 12h. 30m. p. m. ; hour of ending, 1h. p. m. 
Observers, Prof. W. C. Bond and Lieut. J. C. Ives. 
Needle vertical, face of circle north, reading of azimuth circle 
Needle vertical, face of circle south, reading of azimuth circle 
Reading of azimuth circle when plane of instrument is in the idi 
Reading of azimuth circle when plane of instrument is in the tie pure 
Approximate magnetic declination 
OBSERVATIONS FOR MAGNETIC INCLINATION AND INTENSITY —No. 3. 
. 
Def. S. at app. dip. 74° 24’ 50”. 
Def. N. at app. dip. 74° 24’ 50." 
| 
| 
Face of circle. Direct. | 
Def. towards | Def. from the, Ther. | Def. . towards ` Def. from the| Ther. 
the vertical. | the vertical. | Fah. ‘the vertical. | the vertical. | Fah. 
| 
o , 0 2 0 ۰ 0 | o , o , o 
í 4 28 106 55 41 65 70 104 45 43 50 70 
Ent ...... TE 35 106 50 EE 104 50 2۳ 50 EE 
t Sear | ۵۵6 dede ul | 104 55 Bw Lc 
) ےا‎ 22 106 40 ARA ۶ | 104 45 a iw. 
West : 74 28 106 48 al Is | 3104 8 48 65 kids 
kid 106 45 Ai 50 | 70 | 104 50 43 50 70 
| | 
o " ۰ " ° ° , ” [9] 
€ 106 48 50 104 48 50 
— مو‎ i 4l 55 00 ٦ 43 50 0 " 
Corr. for index error of needle ..| + 8 48 | 
o , " 
Deduced inclination ...........| 74 33 38 
D "n o r " 
Sum of means MS d$ dà LL... Hé. 3 40 — — | 
i ; o d n o 1 Hi 
Half sum — dip m TE- BB. Os 74 19 50  1..------ 
o9 , "m o , n 
Diff. of means e£ 4 ` Bee وو وی‎ 60 bs o-o eee 
° , “ o D " 
Half diff. — angles of deflection. |. ........... ar قوج‎ - —— L| 0] 30 29 00 EE 
4 
