DIP AND INTENSITY OF MAGNETIC FORCE. 
738 
TABLE XI. 
The Dips in this table were observed with the instrument that accompanied the Expedition to Melville Island. It had two 
'"tnon needles, and another with a moveable weight fitted upon Professor Mayer’s principle. 
No. 1 was used solely for observations on the magnetic intensity, and its poles consequently were never reversed ; while 
2 and Mayer’s were employed for Dips, and had their poles changed at each observation. The horizontal needle was sus- 
"ded in a stirrup by a fine silk, in an octagon wooden box, furnished with a graduated circle on the inside, and covered with 
lUss top, in which there was fitted a contrivance for moving the needle out of the mag. meridian. 
Until the arrival of the ship at Woahoo, my stay at each place was too short, and my time too fully occupied with astrono- 
'^1 observations and with the business of surveys, for me to give the necessary attention to these delicate observations; but 
that period the observations were regularly made. Unfortunately for the completion of the series upon the magnetic 
^‘nslty, the needles used for that purpose became corroded upon the passage from Loo Choo to Petropauiski ; by wbich their 
^netic power was much diminished ; and as the amount of the change could not be ascertained, I have thought it advisable 
to incumber the table with the observations, those with the horizontal needle excepted. 
’ate. 
'^ 26 . 
‘^ 27 . 
S29. 
pi 
^ 26 . 
'^ 27 . 
k 
'^28. 
Place. 
N.W. America, 
Chamisso Island, 
England, . 
Petropauiski, 
San Francisco, 
Macao, 
Woahoo, 
Loo Choo, 
Acapulco, 
Latitude. 
North. 
0 
70 
31 
0 
160 
66 12 
Eg 
53 01 
37 48 
22 
21 
26 
12 
18 
12 
Longitude. 
West. 
30 
161 46 
ham. 
201 15 
122 24 
246 
158 
232 
16 50 
28 
00 
18 
Needle. 
99 51 
No. 2. 
No. 2. 
No. 2. 
M. 
M. 
Mayer. 
Do. 
M. 
M. 
'No. 2. 
M. 
iVr. 
M. 
Mayer 
.M. 
( No. 2. 
^M. 
(No. 2. 
f No. 2. 
1 No. 2. 
f No. 2 
I No. 2. 
f No. 2. 
1 No. 2. 
rM. 
{ M. 
(m. 
No. of 
Readings. 
Marked end, N. Pole. 
Marked end, S. Pole. 
w. 
Up. 
w. 
Down. 
w. 
Up. 
Down. 
0 ' 
0 
/ 
0 
' 
0 
56 
85 33.9 
73 
36 
85 
29.2 
76 
45 
80 
80 39 
73 
13 
83 
35 
74 
10 
60 
Mean. 
76 
36 • 
78 
42 
Mean. 
88 
85 16 
70 
12 
91 
21 
66 
12 
217 
84 28 
70 
43 
91 
06 
66 
12 
80 
108 14 
51 
45 
121 
18 
43 
51 
170 
108 11 
51 
46 
122 
36 
43 
46 
100 Vib. 
in mag. mer. 
590 
16 s. 
Perpend. 
597 = 
,. 1 
72 
75 43.1 
62 
23.3 
76 
27 
65 
45.1 
48 
65 15 
57 
39 
68 
49 
62 
41 
48 
70 31 
56 
29 
70 
19 
59 
59 
48 
70 30 
56 
32 
70 
20 
60 
01 
. • > 
71 14 
56 
41 
70 
02 
59 
34 
no 
96 26 
48 
50 
97 
00 
49 
24 
100 Vib. 
in mag. mer 
497s. 
9 
Perpend. 
523s. 4 
80 
63 .38 
54 
25 
68 
03 
61 
24 
64 
68 44 
60 
47 
66 
41 
54 
15 
92 
63 35 
54 
15 
66 
46 
61 
52 
.32 
25 34 
18 
55 
37 
31 
31 
56 
32 
25 37 
19 
09 
37 
19 
31 
55 
32 
41 32 
32 
50.5 
47 
13 
40 
00,5 
32 
41 30 
32 
5.3 
47 
16 
39 
54 
84 
43 25.5 
.37 
32.3 
.32 
12.6 
27 
07.2 
96 
42 47.8 
37 
05 
31 
56 2 
27 
03 6 
100 
41 12 
31 
30 
45 
10 
37 
40 
40 
4! 11 
31 
26 
45 
01 
37 
45 
40 
41 19 
31 
43 
45 
05 
37 
45 
Dip. 
N. 
81 03 
77 44 1 
77 39 
77 47 
77 40 
77 22 
77 40 
77 40 
69 58 
63 491 
64 09 
64 11 
64 05 f 
63 38 1 
64 22 J 
62 27 
62 54 
62 25 
29 58} 
29 57 / 
40 35 1 
40 31/ 
35 14.4 I 
34 49 i 
38 571 
.38 55 > 
39 02 J 
Mean Dip. 
N. 
81 03 
77 39 
69 58 
64 02.3 
62 35.2 
29 57.5 
40 33 
35 01.7 
38 58 
