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III. On the Position of the North Magnetic Pole. By Commander James Clark Ross, 



R.N. F.B.S. F.R.A.S. F.L.S. 8^c. 



Received December 19, — Read December 19, 1833. 



1 HE deterniination 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 indefatigable 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 substances 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 : and during our absence from England, a greater step perhaps 

 than any former one has been made, through the indefatigable research of Dr. Fara- 

 day, by his splendid and convincing proofs of its complete identity with electricity. 

 Still much remains to be accomplished relative to terrestrial magnetism ; and accu- 

 rate observations with good instruments, as near the magnetic poles as possible, and 

 in various directions from them, were long considered amongst the desiderata for 

 completing the magnetic theory of the globe. 



These wants, as far as relates to the northern magnetic regions, have been supplied 

 by the expeditions by land and sea that have been sent from England for the disco- 

 very of a north-west passage, to traverse the shores of the American continent, and 

 to contribute to the advancement of science in general. In the department of mag- 

 netism, in particular, the numerous and accurate observations by their distinguished 

 commanders, and those who accompanied them, have been eminently important. 

 Those made to the north-west of the magnetic pole by Captain Sabine, to the south- 

 west by Captain Franklin, and to the south-east and north-east by Captain Parrv, 

 Mr. Fisher, and Captain Forster, have furnished materials that have enabled the 

 British philosophers to point, with a wonderful degree of precision, to the seat of 

 magnetic concentricity. 



