IN WOOD-BUILT AND IRON-BUILT SHIPS. 
63 
2 & 3. Deviations as corrected for constant error. 
Apparent 
azimuth 
of ship’s 
head. 
Deviation. 
Apparent 
azimuth 
of ship’s 
head. 
Deviation. 
+ 
- 
+ 
- 
P 
o / 
o / 
P 
O / 
o t 
0 
2 57 
24 
19 2 
1 
3 38 
25 
20 24 
2 
9 13 
26 
21 47 
3 
12 30 
27 
22 12 
4 
15 48 
28 
20 2 
5 
17 38 
29 
16 32 
6 
19 28 
30 
13 2 
7 
19 3 
31 
7 34 
8 
18 38 
0 
2 57 
9 
17 13 
1 
3 38 
10 
15 48 
2 
9 13 
11 
14 8 
3 
12 30 
12 
12 28 
4 
15 48 
13 
11 28 
5 
17 38 
14 
9 18 
6 
19 28 
15 
5 53 
7 
19 3 
16 
2 28 
8 
18 38 
17 
0 2 
9 
17 13 
18 
2 32 
10 
15 48 
19 
5 52 
11 
14 8 
20 
9 12 
12 
12 28 
21 
11 54 
13 
11 28 
22 
14 37 
14 
9 18 
23 
16 49 
15 
5 53 
4. The neutral position appears to be somewhere near IP, and therefore trial may 
be made with the two assumptions OP’5 and 1P’5. 
5. For trial OP’5, the sums must be taken from 9P to 24 p, and from 25P to 8 p. 
Sum from 9 to 24 = + 88 44— 80 0=+ 8 44 
Sum from 25 to 8= + 115 56—124 30=— 8 34 
Excess of the first . . . . +17 18 
For trial 1P‘5, the sums must be taken from lOP to 25 p, and from 26P to 9P. 
Sum from 10 to 25 = + 71 31 — 100 24=— 28 53 
Sum from 26 to 9= + 133 9—104 6=+29 3 
Excess of the first . . . . —57 56 
6. A change of IP in the assumption has changed the excess” from +17° 18' to 
— 57° 56', or has changed it by 75° 14'. Hence, the assumption which would make 
17 ° 18 ^ 
the “Excess” =0 is 0P-5+1PX7 |o-j4,=0p-5+1PX0-23=0P-5 + 0p- 23=0P73. This is- 
the “approximate neutral position”; and its supplement or 31P’27 is the “approxi- 
mate starboard angle,” or the approximate value of a. 
7. The neutral position being OP’73, the observed deviations which are to be 
grouped for ascertaining the approximate modulus are those from 1 p to 16 p in one 
part, and those from 17 p to 0? in the other part. The sums are respectively 
+204° 40' and —204° 30'; the excess of the first is 409° 10'; dividing by 32, the 
