28 
SUPPLEMENT. 
On the Position of the North Magnetic Pole. By Commander 
James Clark Ross, R.N. F.R.S. F.R.A.S. F.L.S. fyc. 
Received December 19.—read December 19.1833. 
The determination of the position of the Magnetic Poles of 
the earth has ever been considered a desideratum in the science 
of magnetism, of the highest importance ; and the observations 
and experiments of the most ingenious and learned philosophers 
have universally been applied to the solution of this difficult and 
perplexing problem. Vague and unsatisfactory, however, were 
the results of the researches and calculations of the most inde¬ 
fatigable and zealous promoters of that science, arising, doubtless, 
in a great measure, from the discordant observations upon which 
they were founded^—a discordance which was considered to 
arise chiefly from the unequal distribution of the magnetic sub¬ 
stances contained in the earth, and also from the great distances 
at which the observations were made from the centres of the 
powers of those magnetic substances, or, in other words, from 
the magnetic foci, or poles of the earth. 
The primary cause of magnetic phenomena has always been, 
and still is, one of the secrets of nature, although several of the 
laws of magnetism have of late years been gradually developed 1 
and during our absence from England, a greater step perhaps 
than any former one has been made, through the indefatigable 
research of Dr. Faraday, by his splendid and convincing proofs 
of its complete identity with electricity. Still much remains to 
be accomplished relative to terrestrial magnetism; and accurate 
observations with good instruments, as near the magnetic poles 
as possible, and in various directions from them, were long con¬ 
sidered amongst the desiderata for completing the magnetic 
theory of the globe. 
These wants, as far as relates to the northern magnetic re¬ 
gions, have been supplied by the expeditions by land and sea 
that have been sent from England for the discovery of a North 
West Passage, to traverse the shores of the American continent. 
