LINES OF MAGNETIC DECLINATION IN THE ATLANTIC. 
193 
The mean values of A, D and E, from the preceding’ observations, are A=— 35' ; 
D=+26'; and E=+2'. B at Monte Video = —‘0094; and at Plymouth +*0480; 
C— *0095 at Monte Video, and —-0031 at Plymouth, Assuming the values of B to 
have been the same when the Philomel left Monte Video for England in April 1846 
as when she was swung at that station in September 1844, and that its alteration in 
the passage between Monte Video and Plymouth was uniform in respect to time, we 
have the change in the variable term of the correction from —*013 on the 27th of 
April 1846 to +'048 on the following 10th of June; being at the rate of +"0014 for 
each day. The corrections have been applied in accordance with these values of the 
coefficients. 
Determinations in the Hudsons Bay Company s ship the Prince Albert, in a passage 
from England to Hudsons Bay and back, in 1846, by Lieut, {since Commander) 
T. E. L. Moore, R.N. 
The observations of Lieut. T. E. L. Moore, R.N., were made in a voyage from the 
Thames to Moose Fort in Hudson’s Bay and back in the summer of 1846, in the 
Hudson’s Bay Company’s ship “ Prince Albert,” in which ship Lieut, Moore embarked 
by direction of the Admiralty for the purpose of making magnetic observations in 
compliance with a recommendation to that effect from the Royal Society. 
Lieut. Moore was supplied with one of the Admiralty compasses fixed as a standard 
compass; the ship was swung at Greenhithe on the 4th of June 1846 (before her 
departure from the Thames), and the influence of the iron examined on the eight 
principal points of the compass as follows : — 
Table VI. — Disturbance of the Compass in the Hudson’s Bay Company’s ship 
Prince Albert. 
Ship’s head. 
Disturbance 
towards the 
west. 
Ship’s head. 
Disturbance 
towards the 
west. 
Ship’s head. 
Disturbance 
towards the 
west. 
Ship’s head. 
Disturbance 
towards the 
west. 
N. 
— 0 48 
w. 
+ 1 12 
S. 
+ 0° 20 
E. 
— \ 30' 
N.W. 
+ 1 00 
s.w. 
+ 0 40 
S.E. 
-0 40 
N.E. 
-1 10 
From whence we obtain A= — 1 1' ; D= + 12' ; E= — 2' ; B= -l-’0236 ; C= — ’0099 ; 
the (approximate) inclination being 68° 52'. 
On the 26th and 27th of August following, the “ Prince Albert” being then at the 
anchorage at Moose Fort in Hudson’s Bay, her head was placed successively on seven 
of the same points (N.W. being omitted on account of difficulties arising from the 
strength of the tide), and the bearing of an object ten miles distant was observed 
with the head on each point. 
