IN THE lEON SHIPS OF THE EOYAL NAVY. 
345 
2. The gradual decrease in the value of D is well marked in those ships in which the 
position of the compass has remained unchanged, and direct comparison has been thus 
atforded. 
o / o I o I 
Himalaya . 
in 
4| years, 
decrease from 
3 
61 
to 
3 
18 
= 
0 
33 
Urgent . . . 
5 ? 
4 
55 
55 
2 
68 
55 
2 
12 
55 
0 
46 
Simoom . . 
55 
7f 
55 
55 
3 
67 
55 
3 
26 
55 
0 
32 
Vulcan . . . 
55 
55 
55 
3 
20 
55 
2 
48 
55 
0 
32 
Birkenhead . 
55 
4 
55 
55 
2 
63 
55 
2 
12 
55 
0 
41 
Trident . . . 
55 
io 
55 
55 
4 
03 
55 
3 
26 
55 
0 
37 
Triton . . . 
55 
9i 
55 
55 
4 
02 
55 
2 
37 
55 
1 
26 
Supply . . . 
55 
55 
55 
3 
40 
55 
2 
16 
55 
1 
26 
Bloodhound 
55 
10 
55 
55 
3 
40 
55 
2 
31 
55 
1 
9 
Jackal . . . 
55 
14 
55 
55 
4 
67 
55 
3 
01 
55 
1 
66 
Myrmidon . 
55 
55 
55 
3 
23 
55 
2 
46 
55 
0 
38 
Harpy . . . 
55 
14 
55 
55 
2 
64 
55 
2 
32 
55 
0 
22 
Lizard . . . 
55 
13 
55 
55 
3 
49 
55 
3 
4 
55 
0 
45 
Onyx .... 
55 
4 
55 
55 
3 
42 
55 
3 
26 
55 
0 
16 
Dover . . . 
55 
61- 
^2 
55 
55 
2 
38 
55 
2 
23 
55 
0 
15 
3. In assuming the normal amount of quadrantal deriation in iron steam-ships as from 
2° to 4°, it will be seen, from the accompanying analysis, that thirty-four of the forty- 
two ships in Her Majesty’s Navy, or 76 per cent., are included in this condition, thus: 
Quadrantal deviation, between 1 and 2, 
55 
55 
55 
2 
55 
55 
55 
55 
2 
55 
3, 
55 
55 
55 
55 
3J 
55 
55 
55 
3 
55 
4, 
55 
55 
55 
55 
55 
55 
55 
3 
55 
5, 
55 
55 
55 
4 
55 
5, 
55 
55 
55 
6 
55 
7, 
2 vessels, of 1391 and 462* tons. 
1 
55 
164 tons. 
11 
55 
1981 to 180 tons. 
10 
55 
1764 „ 270 tons. 
10 
55 
3463 „ 292 tons. 
3 
55 
1980 „ 603 tons. 
2 
55 
440 „ 340 tons. 
1 ,, 267 tons, as also Gt. Eastern. 
2 „ 1954f to 267 tons. 
Two questions of import here arise: — Are the results of this analysis to be deemed 
conclusive 1 and, if so, under what conditions do large quadrantal deviations occur 1 
It will be remembered that the two earliest iron vessels experimented on by Mr. 
Airy, — the ‘Eainbow’ in 1838, and the ‘Ironsides’ in 1839, — vessels probably in those 
3 A 
MDCCCLX. 
* A sailing vessel. 
t A floating battery. 
