MAGNETIC OBSERVATIONS. 79 
OBSERVATIONS—Continued. 
Station, Cambridge Observatory ; latitude 422 22' 48" ; longitude 4h. 44m. 29.68. 
Needle, A. Date, August 9, 1850. Hour of beginning, 4h. 15m. p. m. ; hour of ending, 4h. 30m. p. m. 
Observers, Prof. W. C. Bond and Lieut. A. W. Whipple. 
[e] D ” 
í 47 40 
Needle vertical, face of circle north, reading of azimuth circle 47 69 
i «6 
47 70 
Needle vertical, face of circle south, reading of azimuth circle 47 70 
47 67 
Reading of azimuth circle when plane of instrument is in magnetic meridian 48 00 10 
ading of azimuth circle when plane of instrument is in true meridian 38 18 45 
Approximate magnetic declination 9 41 25 W. 
OBSERVATIONS FOR MAGNETIC INCLINATION AND INTENSITY —No. 3. 
Def. S. at app. dip. 74° 23/. Def. N. at app. dip. 74° 8 
Face of circle. Direct. 
Def. towards | Def. fromthe Ther. | Def. towards | Def. from the! Ther. 
the vertical. | vertical. Fahr. vertical. vertical. Fahr. 
o D o , o t o o , o f o 
74 108 18 40 10 75 105 07 43 35 75 
East -... f 74 30 108 28 do "19 Ka E. 105 05 43 ۰ 85 zante 
l 74 15 108 15 505 eet. 105 15 "E رم‎ 687 
74 18 108 28 30 37 J. 32. 105 00 ES 0 
West 74 30 108 28 a) “20 Nidia 105 00 ES ب‎ +4870 
74 15 108 28 40 995 lo E 104 55 4128-429 cee E 
[e] , " [e] , ” | o , " 
eans 108 24 10 I vua 105 03 40 
^ 74 23 0 40 12 50 peer d 43 29 20 
d | , ” Am B. پہے‎ 
Sum .... 148 ہی‎ QU — e Li 148 33 00 i 
D ° , ” ° 1 ^" 
Half sum — dip 14 18 80  — Su sss ae Oe ss. : 
acr " 1 o , " 
Difference. 68 11 20 | NEL X4 ` oco وا‎ S 
: SE b ER 
Half differen gle of de- ~ d 
O 34 05 40 ۳ 30 47 10 
