66 Professor Hansteen on the Position and Revolution 



N is the strongest pole in the north hemisphere, and its 

 revolution round the north pole of the earth is performed in 

 1740 years. 



S is the strongest pole in the south hemisphere, and its revo- 

 lution round the south pole of the earth is performed in 4609 

 years. 



n is the weakest pole in the north hemisphere, and its revo- 

 lution is performed in 860 years. 



s is the zeeakest pole in the south hemisphere, and its revo- 

 lution is performed in 1304 years. 



Since this table was computed, Professor Hansteen has ob- 

 tained many new sets of magnetical observations, and particu- 

 larly those which have been made during the British voyages 

 of discovery to the Arctic Regions. These he has diligently 

 compared, and thus obtained new determinations of the posi- 

 tion and times of revolution of the magnetic poles of the earth. 

 The results of these we shall now lay before our readers in a 

 very abbreviated, but, we trust, intelligible and useful form. 



1. On the Position, Sfc. qfN, the strongest Magnetic Pole in 



North America. 



By combining four observations on the declination of the 

 needle, made on board his Majesty's sloop Brazen in Hudson's 

 Bay, in 1813, and which Professor Hansteen inspected in the 

 Marine Chart Office at the Admiralty in London, he obtained 

 the following results : 



