MAGNETIC OBSERVATIONS. "1 
OBSERV ATIONS-— Continued. 
Station, Cambridge Observatory ; latitude 420 22 48"; longitude 4h. 44m. 29.68. 
Needle, A. Date, August 9, 1850. Hour of beginning, 3h. 40m. p. m. ; hour of ending, 4h. 6m. p. m. 
Observers, Prof. W. C. Bond and Lieut. A. W. Whipple. 
0 r " 
47 40 
Needle vertical, face of circle north, reading of azimuth circle 47 69 
47 45 
e $ 47 70 
. Needle vertical, face of circle south, reading of azimuth circle 47 70 
¢ 47 ۰ 
Reading of azimuth circle when plane of instrument is in the magnetic meridian 48 00 10 
Reading of azimuth circle when plane of instrument is in the true meridian 38 18 45 
Approximate magnetic declination 9 41 25 ۰ 
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 the Ther. | Def. towards | Def. from the Ther. 
the vertical. | vertical. Fah. | the vertical.| vertical. Fah. 
(1) (2) (2) 
D ut o , NP. o ° , Eo مر‎ o 
74 30 104 25 44 22 75 110 60 87 15 75 
East 74 30 104 30 MA E سو سے‎ 110 60 ENT > مد تا‎ 
74 15 104 15 48 JÉ سو ہے‎ 110 55 QE Ae ,-06, 
74 18 104 00 Si O MA 110 58 A c3 سا‎ 
West 74 30 103 55 XE S88 ما‎ 110 58 WH ee. تتھ یں‎ 
74 15 104 15 926۳ Rh ~ bs oe 110 53 | lE - اف ہک‎ 
o , " 0 , ” , "m 
( 104 13 20 (1) 110 57 20 1 
Mime 74 2 001 IM m 75 (Dar om 15 
[e] , ” ° , ” 
Difference 58. 53 10 a L 8T ANE بی‎ dei 
| 
Half difference, or angle of de- o P ee y6 و از‎ 
flection 8 29-08 O Ti cod. Sia: O saat 
Se e] , " 0 7 " 
Sum of means 148 SM 380 وع عم او‎ MS 17 40 ^ uos 
a cr ” o H " 
Half sum — dip ee oua... 4: 8 GO خی‎ E 
