A Voyage of Discovery and Research in the Southern and Antarctic Regions/Volume 2/Appendix 10
APPENDIX, No. X.
NOTE ON THE POSITION OF THE MAGNETIC POLES.
(Referred to, Vol. I. p. 247., and Vol. II. p. 357.)
Professor Gauss, in his General Theory of Terrestrial Magnetism, states, that "the exact computation of the places of these two poles, according to our elements, gives them as follows:—
"1. In 73° 35′ north latitude, and 95° 39′ west longitude from Greenwich, the total intensity being 1.701 on the unity in common use.
"2. In 72° 35′ south latitude, and 152° 30′ east longitude, the total intensity 2.253.
"According to Captain James Ross's observation, the north magnetic pole falls 3° 35′ to the south of its position, according to our calculation, which gives at that place a direction of the magnetic force differing 1° 12′ from observation, as may be seen in the table of comparisons.[1] We must expect a considerably greater displacement of the position of the southern pole. At Hobart Town, which is the nearest station to this pole, calculation gives too low a dip by 3° 38′, as far as the observation can be depended upon. It seems probable, therefore, that the actual south magnetic pole is considerably to the north of the position given by our calculation; and that it may be looked for in about 66° S. latitude, and 146° E. longitude."
It was this last paragraph in which M. Gauss infers the place of the south magnetic pole, that was the occasion of my instructions directing me to seek it in latitude 66° S., rather than in the position which M. Gauss's theory places it. The result has proved the latter to be the more correct; and it is curious to observe that the error of its computed place is not very different from that of the north magnetic pole. In the latter case, my observations placed the pole 3° 35' south of that given by M. Gauss's theory; and a careful combination of all the observations of our late voyage, assigns the position of the south magnetic pole in 75° 5' S., and longitude 154° 8' E., or about 2° 30' also south of its place as computed by Professor Gauss. It is to be hoped that the accession of so great a number of observations as the Antarctic Expedition has supplied, will afford M. Gauss the means of perfecting his theory, by which, even with the inaccurate observations he before possessed, enabled him to calculate within very narrow limits the three magnetic elements at any given point on the surface of our globe.
THE END.
- ↑ Scientific Memoirs, vol. ii. part 6. p. 224.