Mni d 
MAGNETIC OBSERVATIONS. 
OBSERVATIONS—Continued. 
141 
Station, Camp 128, Rio Colorado ; latitude 340 23’ 10".10 ; longitude Th 
. 36m. 25. 66s. 
Needle, B. Date, February 21, 1854. Hour of beginning, 3h. 15m. p. m.; hour of ending, 3h. 30m. p. m. 
Observer, Lieut. J. C. lves, Topographical Engineers. j 
Needle vertical, face of circle north, reading of azimuth circle 
Needle vertical, face of circle south, reading of azimuth circle 
Reading of azimuth circle when plane of instrument is in the magnetic 
Reading of azimuth circle when plane of instrument is in the true meridian 
Approximate magnetic declination 
DER 
07 49 E. 
OBSERVATIONS FOR MAGNETIC INCLINATION AND INTENSITY —No. 4. 
Face of circle. 
Direct. 
Def. with wt. 23 gr. 
Def. with wt. 3 gr. 
Def. towards |Def. from the Ther. | Def. towards |Def. from the Ther. 
the vertical. | vertical. Fahr. | the vertical. | vertical. Fah. 
(1) 2) (1) 2) 
o ° , o , ° Bl + o 
ou Zs 94 28 26 12 75 102 32 17 60 75 
East 60 27 94 25 Wo. DE 192 30 ہے‎ MN EEE 
60 30 94 25 本 | 102 40 IT. 032 ۱ kawaq Fe eae 
60 28 94 33 " A EPA | 102 28 ` Si a EE 
West 60 25 94° 30 WË Wr Lu 102 30 D^ nel 
60 21 94 32 20 10 | 75 | 102 20 17 50 | 75 
i | | 
° , 好 0 2 9 à , ° 
(1 94 28 50 1 )1( 102 30 00 } 
Means 60.35 40 ] (2) 26 11 30 C (2) 17 55 50 3 
Cor. for index error of needle...| + 8 48 
Seen goe 
0 D ” 
Deduced inclination....-.----- 60 34 28 | 
| 
1 6 , ” o f - | 
Differences uu e galo c DE Ss 84 34 10 | 00007 
E | 
° , ” [e] fo 
Half diff. or angles of deflection. .|.--.......-- 3 ws Abe Pi وس‎ 43 17 ۰ 06 ۰ "eee 5 
¥ o , "m [e] , » 
Sum of means IM 4 2. —q---—---- 120 435 DM. ewe eee 
o r rr 0 4 a4 
60 20 10 60 12 55 تست‎ 
Halt J 
