270 
COMMANDER JOHNSON’S MAGNETIC EXPERIMENTS 
stationed at X ; and the necessary signals were arranged for the simultaneous obser- 
vations between that station and A on board*. 
Mr. Bingham of the Garryowen willingly attended to swinging the vessel, and 
also observed the direction of her head at the position G. These arrangements left 
me at liberty to make the more important observations at A and B, to keep a check 
with the instrument on the forecastle as to the direction of the vessel’s head, and oc- 
casionally to overlook the men who were watching the other compasses. 
The necessary preparations having been made, the Garryowen was warped round 
to all the points of the compass, but not till after frequent interruptions, sometimes 
for several days together, by rain and gales of wind. 
The bearings of the cone of the distant mountain from the positions A and B, as 
well as the simultaneous bearings between A and X, were observed when the vessel’s 
head was at each point, and from these bearings the deviation of the compass pro- 
duced by the local attraction of the vessel was deduced. 
These observations are registered in Table II., and the repetition of them during 
another revolution of the vessel is inserted in Table III. 
Table I. 
Simultaneous Observations made with Nine Compasses in different parts of the 
Vessel, the Bell being struck as the signal for observation. 
Date. 
True mag- 
netic direc- 
tion of ves- 
sel’s head. 
Direction 
of vessel’s 
head by 
compass F. 
Devia- ! 
tion at 
F. 1 
Direction 
of vessel’s 
head by 
T. 
Devia- 
tion at 
T. 
Direction 
of vessel’s 
head by 
G. 
Devia- 
tion at 
G. 
Direction 
of vessel’s 
head by 
A. 
Devia- 
tion at 
A. 
Direction 
of vessel’s 
head by 
O. 
Devia. 
tion at 
O. 
Nov. 5. | 
Therm. 52° T. 
Barom. 29'8. 
Nov. 4. j 
Therm. 56°. 1 
Barom. 29'7. ! 
North. 
N.E. 
East. 
S.E. 
South. 
s.w. 
West. 
N.W. 
North. 
N. 33 0 E. 
N. 67 0 E. 
S. 64 30 E. 
S. 1 0 E. 
S. 65 0 W. 
N. 66 30 W. 
N. 32 0W. 
0 / 
0 0 
12 0 
23 0 
19 30 
1 0 
20 0 
23 30 
13 0 
N. 26 0 E. 
N. 74 30 E. 
S. 59 30 E. 
S. 30 15 E. 
S. 10 30 E. 
S. 8 30 W. 
S. 35 SOW. 
N. 30 0 W. 
o / 
26 0 
29 30 
30 30 
14 45 
10 30 
36 30 
54 30 
15 0 
N. T 0 E. 
N. 45 0 E. 
East. 
S. 45 0E. 
S. 1 0 E. 
S. 45 0 W. 
N. 85 0 W. 
N. 40 0 W. 
0 / 
1 0 
0 0 
0 0 
0 0 
1 0 
0 0 
5 0 
5 0 
N. °8 20 E. 
N. 55 0 E. 
N. 80 40 E. 
S. 39 30 E. 
S. 1' 0E. 
S. 33 0 W. 
S. 80 0 W. 
N. 38 0 W. 
0 / 
8 20 
10 0 
9 20 
5 30 
1 0 
12 0 
10 0 
7 0 
N. 16 30 E. 
N. 72 0E. 
S. 67 0 E. 
S. 35 0 E. 
S. 5 0 E. 
S. 26 0 W. 
S. 63 15 W. 
N. 64 0W. 
16 30 
27 0 
23 0 
10 0 
5 0 
12 0 
26 45 
19 0 
Direction of 
vessel’s head by 
Q. 
Devia- 
tion at 
Q- 
P. 
at 
P. 
B. 
at 
B. 
c. 
at 
C. 
Nov. 5. 
Therm. 52° I. ^ 
Barom. 29'8. |_ 
Nov. 4. 
Therm. 56°. 1 
Barom. 29 - 7. 
North. 
N.E. 
East. 
S.E. 
South. 
S.W. 
West. 
N.W. 
N. 18° O' E. 
N. 56 15 E. 
S. 73 8 E. 
S. 36 33 E. 
S. 9 51 E. 
S. 14 3 W. 
S. 59 3 W. 
N. 32 21 W. 
18 0 
11 15 
16 52 
8 27 
9 51 
30 57 
30 57 
12 39 
N. 1 24 E. 
N. 47 48 E. 
S. 81 33 E. 
S. 42 12 E. 
South. 
S. 41 30 W. 
S. 84 23 W. 
N. 47 48 W. 
1 24 
2 48 
8 27 
2 48 
0 0 
3 30 
5 37 
2 48 
N. 9 40 E. 
N. 56 0E. 
N. 82 30 E. 
S. 41 0 E. 
S. 5 0 E. 
S. 27 30 W. 
S. 73 30 W. 
N. 40 30 W. 
9 40 
11 0 
7 30 
4 0 
5 0 
17 30 
16 30 
4 30 
N. 1 24 E. 
N. 43 36 E. 
East. 
S. 42 12 E. 
South. 
S. 45 0 W. 
N. 86 30 W. 
N. 36 33 W. 
1 24 
1 24 
0 0 
2 48 
0 0 
0 0 
3 30 
8 27 
* The time was noted as a check to any mistake in the identity of the observations ; but I have not thought 
it necessary to prolong the tables by inserting it. 
