MAGNETIC OBSERVATIONS. 
143 
OBSERVATIONS—Continued. 
Station, Camp 129, Rio Colorado; latitude 34° 27' 26". 44 ; longitude Ih. 36m. 45.24s. 
Needle, B. Date, February 22, 1854. Hour of beginning, 5 h. p. m .; hour of ending, 5 h. 30m. p. m. 
Observer, Lieut. J. C. Ives, Topographical Engineers. 
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 meridian 
Reading of azimuth circle when plane of instrument is in the true meridian 
Approximate magnetic declination....... 
o 
' 
66 
45 
66 
51 
66 
60 
66 
52 
66 
52 
66 
42 
66 
50 
OBSERVATIONS FOR MAGNETIC INCLINATION AND INTENSITY—No. 4. 
Face of circle. 
Direct. 
Def. with wt. 2J gr. 
Def. towards 
the vertical. 
(1) 
Def. from 
the vertical. 
( 2 ) 
Tlier. 
Fah. 
Def. with wt. 3 gr. 
Def. towards 
the vertical. 
( 1 ) 
Def. from 
the vertical. 
( 2 ) 
Ther. 
Fah. 
East. 
West. 
o ' 
60 25 
60 28 
60 25 
60 25 
60 27 
60 25 
o ' 
94 25 
94 30 
94 28 
94 20 
94 25 
94 20 
o ' 
26 08 
26 10 
26 10 
-26 45 
*26 60 
*26 58 
o 
65 
65 
o ' 
102 40 
102 35 
102 48 
102 40 
102 45 
102 50 
o ' 
17 60 
17 55 
17 58 
17 58 
17 50 
17 40 
Means .. 
o ' " 
60 25 50 
j (1) 94 24 40 ) 
1 (2) 26 31 50 \ 
o 
65 
(1) 102 43 10 
(2) 17 53 30 
Cor. for index errror of needle.. 
Deduced inclination 
+ 8 48 
60 34 38 
Differences. 
67 52 50 
84 49 40 
Half diff. or angles of deflection. 
33 56 25 
42 24 50 
Sum of means. 
120 56 30 
120 36 40 
Half sum dip.. 
60 28 15 
60 18 20 
o 
65 
65 
o 
65 
®For these three observations the number of degrees first recorded in the primary note-book were “ 25°”. After¬ 
wards they were changed to “26°”. It is believed that the original record was correct. A. W. W. 
