384 
LIEUT. -GENEEAL SABINE ON TEEEESTEIAL MAGNETISM. 
same geographical meridian. This line, at the present magnetic epoch, has a double 
curvature. I was myself the first, I believe, to trace (Philosophical Magazine for 
February 1829, Art. XY.) the position on the globe of the magnetic equator as thus 
defined, and to exhibit it in comparison with the line of no dip, from which it differs 
very considerably in geographical position*. 
In concluding this paper, I should be unjust to the memory of Sir James Ross and to 
my own high regard to his memory, if I failed to record my conviction that, by the 
remarkable character of his geographical discoveries, by the perseverance and indomi- 
table resolution which he displayed on so many occasions, and by that which we of the 
Eoyal Society are peculiarly able to appreciate and peculiarly bound to honour and 
applaud, i. e. the large extent and high character of his contributions to the advancement 
of the sciences connected with physical geography in the polar regions of both hemi- 
spheres, he has established a claim to be regarded as the first scientific navigator of 
his country and of his age. 
* In an earlier paper (Philosophical Transactions, 1864, Art. YI.) I availed myself of what appeared to me 
a suitable occasion to express the conjectural belief, which I have long entertained, that of the two magnetic 
systems which are distinctly recognizable in the phenomena of the magnetism of the globe, one has a terrestrial 
and the other a cosmical source. It is, I believe, the latter of these two systems which, by its progressive trans- 
lation, gives rise to the phenomena of secular change, and to those magnetical cycles which owe their origin to 
the operation of the secular change. I have naturally seen with great pleasure that this conjectural anticipa- 
tion is received, and is viewed in the same light, by the author of the able Essay which obtained the Adams 
Prize at Cambridge in 1865, and which has been since published under the title of “ Terrestrial and Cosmical 
Magnetism, by Edwabd ’W’alkeb, M.A., late Eellow of Trinity College, Cambridge, &c.” I may add my entire 
concurrence with the following statement of that gentleman in § 185, p. 298, of the work referred to. 
“ Our final conclusion, therefore, upon the whole subject seems to be, that the magnetic influence at any point 
of the globe is the result of two distinct magnetic systems, the principal of which is the magnetism proper of 
the globe, having its [northern] point of greatest attraction in the north of the American Continent, whilst 
the weaker system is that which results from the magnetism induced in the earth by cosmical action, and of 
which the [northern] point of greatest attraction is at present in the north of the Asiatic Continent. Thus the 
direction of the magnet at any point results from the superposition of the two systems , — ‘ the nearest pole 
being always predominant over the more remote.’ ” 
