66 
MR. AIRY ON THE OBSERVED DEVIATIONS OF THE COMPASS 
No 
1. 
2. 
t. 
4. 
Ship’s name 
Erebus. 
Place of observation 
Gillin 
gham. 
Porto Praya. 
St. Helena. 
Cape 
of Good Hope. 
Time of observation 
Index correction 
+ 0° 16' 
-0' 
24' 
0° 
0' 
+ 0" 
19' 
Approximate modulus 
•069 
•033 
•008 
•020 
Approx, starboard angle ... 
0”- 
40 
O'”- 
93 
88 
14‘’-98 
Observed 
Observed 
Observed 
Observed 
deviation 
Residual 
deviation 
Residual 
deviation 
Residual 
deviation 
Residual 
uncor- 
error. 
uncor- 
error. 
uncor- 
error. 
uncor- 
error. 
reeled. 
reeled. 
reeled. 
reeled. 
P 
f 0 
O 
— 0 
6 
(-6 
9) 
+ 0 
56 
( + 0 
11) 
O 
+ 0 
4 
(-0 
6) 
O 
-0 
24 
(-0 18) 
1 
+ 0 
49 
0 
0 
+ 1 
17 
+ 0 
11 
+ 0 
16 
+ 0 
1 
-0 
24 
-0 6 
2 
+ 1 
39 
-}- 0 
6 
+ 1 
53 
+ 0 
27 
+ 0 
28 
+ 0 
10 
-0 
1 
-fO 31 
3 
+ 2 
16 
+ 0 
5 
+ 2 
12 
+ 0 
29 
+ 0 
51 
+ 0 
29 
-0 
11 
+ 0 34 
4 
+ 2 
59 
+ 0 
14 
+ 2 
10 
+ 0 
14 
+ 1 
10 
+ 0 
46 
— 0 
22 
-fO 35 
5 
+ 3 
18 
+ 0 
7 : 
+ 2 
30 
+ 0 
23 
+ 0 
48 
+ 0 
23 
-0 
31 
-fO 37 
6 
+ 3 
46 
+ 0 
17 1 
+ 2 
47 
+ 0 
34 
+ 0 
57 
+ 0 
31 
— 0 
51 
4-0 25 
7 
+ 4 
53 
+ 1 
13 1 
+ 2 
40 
+ 0 
24 
1 0 
55 
+ 0 
29 
— 1 
2 
+ 0 21 
8 
+ 3 
42 
( + 0 
1) 
+ 1 
56 
(-0 
18) 
+ 0 
32 
( + 0 
7) 
— 1 
15 
( + 0 12) 
9 
+ 3 
17 
— 0 
16 ! 
+ 1 
44 
-0 
25 
+ 0 
13 
-0 
9 
— 1 
34 
-0 6 
O 
fin 
10 
+ 2 
50 
— 0 
25 
+ 1 
18 
-0 
40 
-0 
5 
-0 
24 
— 1 
43 
-0 16 
CO 
11 
+ 2 
21 
— 0 
30 
+ 1 
25 
+ 0 
5 
-0 
20 
— 0 
35 
— 2 
1 
-0 38 
p< 
12 
+ 1 
53 
-0 
26 
+ 1 
9 
-0 
19 
-0 
20 
-0 
31 
— 1 
53 
-0 37 
CO 
13 
+ 1 
23 
— 0 
17 
+ 0 
25 
-0 
44 
-0 
25 
-0 
31 
— 1 
41 
-0 33 
O 
14 
+ 0 
48 
-0 
10 
+ 0 
42 
-0 
5 
-0 
30 
— 0 
31 
— 1 
26 
-0 29 
pd 
15 
+ 0 
19 
+ 0 
7 
+ 0 
32 
+ 0 
6 
— 0 
24 
-0 
19 
— 1 
14 
-0 29 
16 
-0 
28 
( + 0 
7) 
+ 0 
39 
( + 0 36) 
-0 
28 
(-0 
18) 
-0 
39 
(-0 7) 
p 
• fH 
17 
-0 
52 
+ 0 
29 
-0 
10 
+ 0 
8 
— 0 
8 
+ 0 
7 
-0 
16 
4-0 4 
18 
— 1 
34 
+ 0 
31 
+ 0 
2 
+ 0 
40 
-0 
1 
+ 0 
17 
+ 0 
2 
4-0 8 
1 "S 
19 
2 
8 
+ 0 
35 
— 0 
9 
+ 0 
46 
+ 0 
14 
+ 0 
36 
+ 0 
40 
4-0 33 
! 2 
20 
— 2 
45 
+ 0 
32 
— 0 
26 
+ 0 
42 
+ 0 
4 
+ 0 
28 
+ 0 
52 
4-0 33 
1 
21 
— 3 
24 
+ 0 
19 
— 1 
34 
-0 
15 
+ 0 
8 
+ 0 
33 
+ 1 
6 
4-0 36 
1 -S' 
1 ^ 
22 
— 4 
3 
-0 
2 
— 1 
24 
+ 0 
1 
+ 0 
9 
+ 0 
35 
+ 1 
5 
+ 0 27 
1 
23 
-4 
40 
— 0 
28 
— 1 
49 
-0 
21 
-0 
12 
+ 0 
14 
+ 1 
14 
+ 0 29 
24 
-4 
19 
(-0 
6) 
— 1 
33 
(-0 
7) 
-0 
32 
(-0 
7) 
+ 1 
9 
(+0 20) 
25 
-4. 
9 
— 0 
4 
— 1 
15 
+ 0 
6 
-0 
29 
-0 
7 
+.0 
51 
4-0 1 
1 
26 
— 3 
51 
— 0 
4 
— 1 
5 
+ 0 
5 
-0 
25 
-0 
6 
+ 0 
33 
— 0 16 
1 
27 
— 3 
28 
-0 
5 
-1 
25 
-0 
53 
— 1 
3 
-0 
48 
+ 0 
15 
— 0 30 
28 
-3 
3 
-0 
12 
— 1 
15 
-0 
35 
-0 
40 
— 0 
29 
+ 0 
3 
— 0 35 
29 
— 2 
30 
-0 
18 
-0 
52 
— 0 
31 
-0 
33 
-0 
27 
-0 
2 
— 0 32 
30 
— 2 
1 
-0 
31 
— 0 
20 
-0 
21 
— 0 
27 
— 0 
26 
-0 
10 
-0 29 
31 
— 1 
12 
-0 
28 
-0 
27 
-0 
49 
-0 
2 
-0 
7 
— 0 
16 
-0 23 
0 
+ 0 
24 
o 
+ 0 
32 
o 
+ 0 
34 
o 
+ 0 
35 
! Quad ran tal coefficients ...V 
— 0 
23 
-0 
24 
-0 
36 
-0 
38 
+ 0 
23 
+ 0 
20 
+ 0 
34 
+ 0 
34 
; 
- 0 
20 
-0 
36 
-0 
30 
-0 
33 
j Mean quadrantal coefficient 
+ 0 
23 
+ 0 
28 
j 
+ 0 
34 
4-0 
35 
True modulu 
s 
•069 
-033 
i -008 
1 
•020 
True starboard angle 
O 
o 
0'’-92 
1 
r 
•86 
14'’-99 
