118 
MAGNETIC OBSERVATIONS, 
OBSERVATIONS—Continued. 
Station, Camp 84, Rio Colorado Chiquito ; latitude 35° 12' 02".77; longitude 7 h. 22 m. 29.64s. 
Needle, B. Date, December 16, 1853. Hour of beginning, 3 h. 40 m. p. m.; hour of ending, 4/t. 10m. p. m. 
Observer, Lieut. J. C. Ives, Topographical Engineers. 
o ' " 
( 89 00 
Needle vertical, face of circle north, reading of azimuth circle..... 7 89 11 
( 89 00 
( 89 00 
Needle vertical, face of circle south, reading of azimuth circle .. ) 89 09 
( 89 15 
Beading of azimuth circle when plane of instrument is in the magnetic meridian... 89 05 50 
Beading of azimuth circle when plane of instrument is in the true meridian.... 102 45 18 
Approximate magnetic declination......... 13 39 28 E. 
OBSEBVATIONS FOE MAGNETIC INCLINATION AND INTENSITY—No. 4. 
Face of circle. 
Direct. 
Def. with wt. 2 gr. 
Def. with wt. 21 gr. 
Def. with wt. 3 gr. 
Def. towards 
the vertical. 
(1) 
Def. from 
the vertical. 
(2) 
Ther. 
Fah. 
Def. towards 
the vertical. 
(1) 
Def. from 
the vertical. 
(2) 
Def. towards 
the vertical. 
(1) 
Def. from 
the vertical. 
(2) 
East___ -j 
O ' 
61 34 
61 32 
61 40 
61 36 
61 38 
61 38 
O ' 
87 45 
87 48 
87 50 
87 50 
87 40 
87 40 
O ' 
35 28 
35 25 
35 30 
35 28 
35 20 
35 28 
o 
43 
O ' 
94 30 
94 20 
94 27 
94 35 
94 15 
94 40 
O ' 
28 15 
28 20 
28 18 
28 00 
28 10 
28 08 
O 1 
102 25 
102 15 
102 30 
102 25 
102 10 
102 20 
o ' 
20 20 
20 12 
20 10 
20 15 
20 20 
20 15 
West.| 
Means.. 
43 
O ' " 
61 36 20 
o 
J (1) 87 
1 (2) 35 
45 30 ) 
26 30 j 
o 
43 
o 
j (1) 94 
1 (2) 28 
27 50 ) 
11 50 j 
o 
( (1) 102 
1 (2) 20 
20 50 ) 
15 20 j 
Cor. for index er- 
, „ 
ror of needle_ 
+ 8 48 
Deduced inclina- 
o ' " 
tion. 
61 45 08 
O ' 
n 
O ' 
o / 
// 
Differences.. 
52 19 00 
66 16 00 
82 05 30 
Half diff. or angles 
o / 
- 
O ' 
" 
o / 
// 
of deflection.... 
26 09 30 
33 08 00 
41 02 45 
O ' 
// 
O r 
1 / 
o / 
// 
Sinn of means- 
123 12 00 
122 39 40 
122 36 10 
o 
„ 
O r 
ft 
O / 
// 
Half sum = dip . - 
61 36 00 
61 19 50 
61 18 05 
