KATE OF REVOLUTION OF THE MAGNETIC POLES. 245 



Hanstccn has calculated the periods of these revolutions 

 to be as follows : 



The weakest north pole in*860 years. 

 The strongest north pole in 1746 years. 

 The weakest south pole in 1304 years. 

 The strongest south pole in 4009 years. 



There are some points of speculation on which 

 Hansteen has ventured which have been smiled at as 

 fanciful ; but they may rather indicate an amount of 

 knowledge in the Brahminical and Egyptian priesthood, 

 beyond what we are usually disposed to allow them, and 

 prove that their observations of nature had led them to 

 an appreciation of some of the most remarkable harmo- 

 nies of this mysterious creation. 



The above terms are exceedingly near 864, 1246, 

 1728, 4320, and those numbers are equal to the mystic 

 number of the Indians, Greeks, and Egyptians, 432 

 multiplied by 2, 3, 4, and 10. On these the ancients 

 believed a certain combination of natural events to 

 depend, and, according to Brahminical mythology, the 

 duration of the world is divided into four periods, each 

 of 432,000 years. Again, the sun's mean distance from 

 the earth is 216 radii of the sun, and the moon's mean 

 distance 216 radii of the moon, each the half of 432. 

 Proceeding with this very curious examination, Han- 

 steen says, 60 multiplied by 432 equals 15,920, the 

 smallest number divisible at once by all the four periods 

 f magnetic revolution, and hence the shortest time in 

 which the four poles can complete a cycle, and return to 

 their present state, and which coincides exactly with the 

 period in which the precession of the equinoxes will 

 amount to a complete circle, reckoning the precession at 

 a degree in seventy-two years.* 



J- Hansteen : Untersuchungen iiber den Magnetismus der Erde, 

 Christiana, 1819. Humboldt : Expose des Variations Maynetiques. 



