MAGNETIC OBSERVATIONS. 
OBSERY ATIONS—Continued. 
157 
Station, Cambridge Observatory ; latitude 420 22' 48” ; longitude 4h. 44m. 29.65. 
Needle, B. Date, May 10, 1854. Hour of beginning, 1h. p. m. ; hour of ending, 1h. 20m. p. m. 
Observers, Prof. W. C. Bond and Lieut. J. C. Ives. 
o , " 
14 48 
Needle vertical, face of circle north, reading of azimuth circle 14 48 
14 55 
14 47 
Needle vértical, face of circle south, reading of azimuth circle. 14 52 
T 14 46 
Reading of azimuth circle when plane of instrument is in the magnetic meridian 14 49 20 
Reading of azimuth circle when plane of instrument is in the true meridian 5 04 00 
Approximate magnetic declination 9 45 20 W 
OBSERVATIONS FOR MAGNETIC INCLINASTION AND INTENSITY—No. 4. 
Def. with wt. 3 gr. 
` Def with wt. 2} gr. 
Face of circle. Direct. 
e Def. towards ` Def. from Ther. 
the vertical. | the vertical. | Fah. 
o 1 o , o , | o 
74 28 111 40 36 32 | 70 
East TE- 25 111 - 35 36 35 — 
74 21 (ek S| 356 sa. ما‎ 
74 22 111 55 ee P... 
West 74 28 111 50 320۳ ege EE 
74 25 111 50 36 30 | 70 
co | 7 ° 7 1 0 ۳ af | o 
(1) 104 43 40 | 1 (1 111 43 0 1 
Means 74 24 50 ۱ مسج مین‎ |--70 (2) Pee 70 
| | 
Cor. for index error of needle...| + 8 48 | | 
| | 
Qi سر‎ | | 
Deduced inclination. ---------- 74 33 38 | | 
o » | o , ” | 
Differences 60 56 10 E وت‎ atlas 35 Al 30 | دا یا‎ i 
e | | 
| | 
S [e] 4 ff | o d r | 
Half diff. or angles of deflection. ------------ 30 28 05 | -------- 37 35 45 | -~------ 
L | | 
0 F " o , " | 
Sum of means j us, 3. —. 148 16 10 | ee 
o D " ° , ” | 
Half di کک‎ ۳ DEE 74 08 05 eem 
