192 
LINES OF MAGNETIC DECLINATION IN THE ATLANTIC. 
Circumstances did not permit the Prince Regent to be swung on her arrival at 
Quebec, and we have no other means of assigning the variations of B (C being so 
small that it may be disregarded) than by assuming it to have varied as the tangent 
of the dip, which increased from 69° in the Thames to 79° at the entrance of the 
*0389 tan 
River St. Lawrence. Upon this supposition B= tan69° ~ ^ ’ being the 
dip at the place of observation ; the deviations on the several points in different dips 
are then given by 
sin ^=27'+’9149 tan & sin ^' + 5' sin 2^' + 10' cos 2^', 
and the corrections have been calculated accordingly. 
They appear generally to reconcile the results of the observations on the different 
courses very satisfactorily. 
Determinations in H.M.S. Philomel, in a passage from Monte Video to England in 
1846, hy Captain Sulivan, R.N. 
The observations of Captain Sulivan, R.N. were made in a passage from Monte 
Video to England in 1846 in H.M.S. Philomel. The error of the compass with the 
ship’s head on different points was examined at Monte Video on the 14th of September 
1844, and at Plymouth on the 10th of June 1846, as follows : — 
Table V. 
Disturbance of the Compass in H.M.S. Philomel, Monte Video, September 14, 1844. 
Ship’s head. 
Disturbance 
towards the 
west. 
Ship’s head. 
Disturbance 
towards the 
west. 
Ship’s head. 
Disturbance 
towards the 
west. 
j Ship’s head. 
Disturbance 
towards the 
west. 
N. 
N. by w. 
N.N.W. 
N.w. by N. 
N.W. 
N.W. by w. 
W.N.W. 
w. by N. 
— 0 57 
— 0 58 
-0 56 
-0 50 
-0 49 
— 0 50 
-0 40 
-0 43 
W. 
w. by S. 
w.s.w. 
s.w. by w. 
s.w. 
s.w. by s. 
s.s.w. 
s. by w. 
-0 40 
-0 50 
— 0 48 
— 0 38 
-0 40 
-0 25 
— 0 10 
+ 0 03 
s. 
s. by E. 
S.S.E. 
s.E. by s. 
S.E. 
s.E. by E. 
E.S.E. 
E. by s. 
+ 0 16 
+ 0 39 
+ 0 49 
+ 0 55 
+ 0 55 
+ 0 55 
+ 0 43 
+ 0 22 
i 
E. 
E. by N. 
E.N.E. 
1 N.E. by E. 
N.E. 
j N.E. by N. 
! N.N.i 
N. by E. 
+ 0 03 
— 0 12 
-0 26 
— 0 26 
— 0 22 
-0 29 
-0 45 
-0 55 
Plymouth, June 10, 1846. 
Ship’s head. 
Disturbance 
towards the 
west. 
Ship’s head. 
Disturbance 
towards the 
w'est. 
Ship’s head. 
Disturbance 
towards the 
west. 
Ship’s head. 
Disturbance 
towards the 
west. 
N. 
-d 20 
w. 
+ 1° 27 
S. 
— d 55 
E. 
-4 32 
N. by w. 
-0 19 
w. by s. 
+ 1 58 
s. by E. 
-1 09 
E. by N. 
— 4 36 
N.N.W. 
— 0 12 
w.s.w. 
+ 0 46 
S.S E. 
— 1 37 
E.N.E. 
— 4 07 
N.W. by N. 
+ 0 30 
s.w. by w. 
+ 0 34 
S.E. by s. 
— 2 02 
N.E. by E. 
-4 34 
N.w. 
+ 0 52 
s.w. 
+ 0 33 
s.E. 
— 1 20 
N.E. 
—3 16 
N.w. by w. 
+ 2 13 
s.w. by s. 
+ 0 11 
s.E. by E. 
-1 27 
N.E. by N. 
—3 12 
W.N.W. 
+ 2 39 
s.s.w. 
-fO 05 
E.S.E. 
— 2 47 
N.N.E. 
—2 11 
w. by N. 
+ 2 30 
s. by w. 
-0 30 
E. by s. 
-3 37 
N. by E. 
-1 26 
