MAGNETIC OBSERVATIONS. 105 
OBSERV ATIONS— Continued. 
Station, Camp 73, Jacob's Well; latitude 350 03' 53".49 ; longitude Th. 16m. 56.388. 
"edle, B. Date, November 29, 1853. Hour of beginning, 5h. 40m. p. m. ; hour of ending, Gh. 20m. p. m. 
Observer, Lieut. J. C. Ives, Topographical Engineers. 
o H " 
° ۱ Í 69 30 
Needle vertical, face of circle north, reading of azimuth circle 69 32 
l 69 48 
| f on 
Needle vertical, face of circle south, reading of azimuth circle 69 32 
| 69 50 
Reading of azimuth circle when plane of instrument is in the m li 69 38 40 
Reading of azimuth circle when plane of instrument is in the true ratem 83.22 21 
Approximate magnetic declination 13 43 41E 
OBSERVATIONS FOR MAGNETIC INCLINATION AND INTENSITY —No. 4. 
Def. with wt. 2 gr. | Def. with wt. 2} gr. 
Face of circle. Direct. | e] 
Def. towards | Def. from the! Ther. | Def. — Def, from the Ther. 
the vertical. ev Fah. | the vertical. | the vertical. | Fah. 
(1) (2) (1) (2) 
0 2 [e] , o , [e] 0 , o , 
61 50 81 50 35 30 43 94 18 38 88 کیو سے سر ا‎ 
East ...... 61 55 87 465 Sb. SS cn 94 20 48 0ص‎ 
61 50 87 55 Bee OO Lo —- 94 10 18 33 dl 
í 61 50 87 50 ول‎ [I su 94 25 28 ۰ 88 9 
West 61 45 87 45 BE ME AO 94 30 € € Loc 
( 61 5 87 45 35 35 | 40 94 5 "e iss... 
o ” o ۰ " 0 " 
M (1) 87 48 20 1 )1( 94 23 00 } 00 
eang 61 50 50 d (3) 35 37 40 41. (2) 28 35 20 
Corr. for index error of needle... + 8 48 
o D " 
Deduced inclination ........... 61 59 38 
[o] 7 " o , 7 
Differences 52 10 40 —  ]-------- M و‎ LI 
š ° 0 i o , ” 
Half diff. or angles of deflection. _____ — aes 26 05 20 ”|-------- M59 0 . po 
o 4 ۳1 D " 
Sum of means 123 00 -------- 122 58 3*» سوہ‎ 
o وت‎ i [e] 1 > 
Half sum — dip > 61 43 00 Gen s كت‎ A 
