160 MAGNETIC OBSERVATIONS. 
OBSERV ATIONS— Continued. 
Station, Cambridge Observatory ; latitude 42° 22! 48” ; longitude 4h. 44m. 29.65. 
Needle, A. Date, May 10, 1854. Hour of beginning, 1h. 50m. p. m.; hour of ending, 2h. 10m. p. m. 
Observers, Prof. W. C. Bond and Lieut. J. C. Ives. 
14 52 j 
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 ; o 50 
14 60 D 
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. 
Def. with wt. 23 gr. Def. with wt. 3 gr. 
Face of circle. Direct. 
Def. towards, Def. from Ther. | Def. towards | Def. from Ther. 
the vertical. | the vertical. Fah. | the vertical. | the vertical. | Fah. 
(1) (2) (1) (2) 
NS ow Qro ° ° , SE, ° 
$ 74 35 104 38 43 45 72 11 35 36 45 72 
East .... 74 35 104 40 48 db عم ات ی 46 )5 1110 0 یب‎ y 
N 74 30 104 45 XL 00 وس وحم‎ 111 37 s D +7 
$ 74 30 104 35 45-40 |. EE IS SB Gp” دوہ دی تا‎ 
West 74 28 104 25 439 45 e AS 11 30 38-45 Lice 
N 74 25 104 20 43 55 72 111 20 36 52 72 
"Te] , n + o 7 ” [2] , " o 
Me: (1) 104 33 50 } (1) m 28 20 
— | 74 30 30۱ [055 5 72 | 1G) e 50 = 
Corr. for index error of needle..| + 15 04 
° , ” 
Deduced inclination ........... 74 45 34 
o , ” 0 , H 
Differences 6 4 Ww 1... — 4ü 4 NW Lc ۳ 
0 , " Oo D r 
Half diff. or angles of deflecti 30 38 M o Eosi H ` GS dtt 
, " 0 , " 
Sum of means HS £M 20 pum 48 u ee 
o , ” ° , “ 
Half sum — dip , HO UE 44 0 € LL. 
Station, Cambridge Observatory. Date, May 10, 1854. x 
Reading of azimuth circle when plane of instrument is in the true meridian ; Lie سب‎ EF Š id 
Mean . 5 04 
> CINES 
