368 
MAGNETIC SURVEY OF A PART OF THE SOUTHERN HEMISPHERE. 
ship’s head on different points of the compass, and also some in very nearly the same 
geographical position as the Pagoda. Comparing these, it appears that the effect of 
the iron is nearly the same in both ships ; the observations have consequently been 
corrected from the Table that was used for those taken on board the Pagoda. The 
following comparisons will show how near these corrections approach the truth. 
Lat. 
Long. 
Inclination. 
Ship’s head. 
Tabular 
corrections. 
— 66 06 
s.|- E. N.N.W. 
+ 6 58 
-66 47 
N.W. 
+ 1 31 
— 55 32 
W.N.W. 
+ 1 12 
-57 01 
S.W. ^ \V. 
+ 0 18 
—56 09 
N. by w. % w. 
+ 1 19 
— 66 45 
—68 41 
— 66 09 
-68 14 
s.s.w. 
n. by w. 
s.s.w. 
N.W. 
— 0 18 
+ 1 22 
-0 18 
+ 1 31 
Corrected 
Inclination. 
Observer. 
Remarks. 
-35 22 
-35 06 
-34 58 
-34 16 
-24 00 
-23 59 
-34 36 
-34 31 
-34 48 
-35 07 
-36 42 
-36 58 
-36 06 
-36 24 
117 46 
117 55 
112 59 
113 01 
99 33 
99 15 
25 23 
27 04 
19 33 
20 46 
118 35 
117 38 
116 42 
115 33 
-65 08 
-65 14 
-65 16 
-64 44 
-54 20 
-54 07 
-56 43 
-57 06 
-54 50 
-55 08 
-67 03 
-67 19 
-66 27 
-66 43 
Lieut. 
Lieut. 
Lieut. 
Lieut. 
Lieut. 
Lieut. 
Lieut. 
Lieut. 
Lieut. 
Lieut. 
Lieut. 
Lieut. 
Lieut. 
Lieut. 
Dayman. 
Clerk. 
D A YM AN. 
Clerk. 
Dayman. 
Clerk. 
Dayman. 
Clerk. 
Dayman. 
Clerk. 
Dayman. 
Dayman. 
Dayman. 
Dayman. 
| Difference + 6 
| Difference —32 
| Difference —13 
| Difference + 23 
| Difference +18 
January 9> 1845. 
January 10, 1845. 
January 11, 1845. 
January 13, 1845. 
“The observations thus corrected have been entered in the chart. The lines on the 
chart are drawn by estimation, so as to conform as nearly as possible with the obser- 
vations : some part of the lines laid dow T n by Lieut. -Colonel Sabine (in No. V. of the 
Contributions) from Sir James C. Ross’s observations have been dotted in, to show 
the agreement of the two series. 
“ In the Chart of ‘ Magnetic Declinations,’ a series of observations made on board 
the e Erebus ’ by Sir James C. Ross, between the Cape of Good Hope and Hobarton, 
have been laid down. These observations have been corrected for index error and 
local attraction, in the same way as the other observations during the Antarctic Ex- 
pedition, the same constants being used. 
“ In the chart of intensities, Sir James C. Ross’s observations between the Cape 
of Good Hope and Hobarton have also been entered. These observations are con- 
tained in Lieut.-Colonel Sabine’s Contributions, No. III. and V. The Cape of Good 
Hope is the base station in this case ; but the intensity there has been taken as 0’981 ; 
it is therefore necessary to reduce them to an intensity at the Cape = 1*0, in order 
that they may compare with the intensities taken on board the Pagoda ; this is done 
*981 
by multiplying each of them by = 1*02 nearly. The observations thus cor- 
rected are given in a table at the end of the ‘Pagoda’ observations, together with 
those of variation and inclination by Sir J. Ross, and the inclinations and intensities 
by Lieuts. Smith and Dayman. 
“ In calculating the intensities observed by Lieut. Smith, Hobarton has been taken 
as the base station, and the results by weights only used. The same has been done 
