MAGNETIC OBSERVATIONS. 81 
OBSERVATIONS—Continued. 
Station, Cambridge Observatory ; latitude 42° 22' A8" ; longitude 4h. 44m. 29. 6s. 
Neede, B. Date, August 9, 1850. Hour of beginning, 6h. 40m. p. m.; hour of ending, 6h. 50m. p. ۰ 
Observers, Prof. W. C. Bond and Lieut. A. W. Whipple. 
58 02 ں_ ت 
0 , " 
47 00 
Needle vertical, face of circle north, reading of azimuth circle 47 29 
47 07 
48 26 
Needle vertical, face of circle south, reading of azimuth circle 48 15 
48 40 
Reading of azimuth circle when plane of instrument is in the magnetic meridian 47 49 30 
Reading of azimuth circle when plane of instrument is in the true meridian 38 18 45 
Approximate magnetic declination 9 30 45 W. 
OBSERVATIONS FOR MAGNETIC INCLINATION AND INTENSITY—No. 4. 
Def. with wt. 1} gr. Def. with wt. 2} gr. 
Face of circle. Direct. 
Def. toward | Def. from Ther. | Def. toward | Def. from | Ther. 
the vertical. | the vertical. Fah. | the vertical. | the vertical ah. 
(1) (2) (1) 
o , 0 Lë , o o , o , o 
74 30 79 55 68 55 75 104 00 44 35 75 
۱ East...... 74 28 80 05 وو کہ یا ہہ‎ - 104 05 Ter Let eo 2 5 
| | 74 25 80 07 @ d Lx j 104 5 u S Las 
x 74 وو‎ | 
West | وو نووا‎ | 
74 20 | | 
| | 
o 7 ” o L " o , 
80 01 10 (1) 104 01 40 l ہیں گی‎ 
Mi تی‎ "usc (eui: از‎ HEV ENS TZ 
[ [e] , " o , LÀ 
Differences A Ho 8939 7 PB MW 1... 
1 
B ۳ o D " o , " ] 
Bp cóc: or angles of de- TE" — e a ور‎ ¿All 
, ” 0 , > 1 
| Sum of means is $ وو‎ 1 — ws ک8‎ S lo 
| 
i & 2 ” d c au di ۱ 
۱ Half sum — dip 74 12 40 س د د‎ 34 c6 25 کے‎ 9 
| 
