GEOLOGY. 163 



equator the Ferrogeneous is wholly reduced, and becomes 

 noble. 



781. There is obviously, however, less iron at the 

 south- than the north-pole, because the greatest part of 

 the planet is there covered with water, and thus in general 

 with less earth less metal also is to be found. From 

 this alone it may be explained why the magnetic needle 

 conveyed beyond the equator still remains horizontal and 

 first inclines about the tenth degree of southern latitude 

 towards the south-pole. 



782. The north-pole is thus more energetic than the 

 south-pole, so that the two poles must be also inversely 

 related to each other. It is only from this antagonism of 

 the two poles of the earth that we comprehend, why upon 

 the southern hemisphere the south-pole of the needle 

 dips towards the earth, and why the needle does not turn 

 completely round. For if there was an equal quantity 

 of iron in both hemispheres of the earth, the southern 

 must have the same magnetic pole, and thus attract the 

 north-pole of the needle; and under the equator the 

 needle must have actually no direction. The cause of 

 the direction and dip of the needle rests thus in the 

 antagonism of the two poles of the earth, and this again 

 in the unequal masses of iron. 



783. The action of terrestrial magnetism does not 

 reside in the iron formation alone, but in its antagonism 

 to the reduced ores. The terrestrial magnetism is a 

 tension between iron and silver. The lead imparts the 

 poles. 



784. As the earth is a globe, so are the two masses of 

 iron situated nearer to its axis than the masses of silver 

 and lead. If therefore the latter exert also any influence 

 upon the direction of the magnetic needle, yet neverthe- 

 less the poles of magnetism must coincide nearly with 

 the poles of the earth's axis, because the exciters of 

 magnetism operate in this direction. 



785. The magnetic meridian runs indeed in general 

 from pole to pole, but as it is not the earth's axis, which 

 determines the magnetism, but the metallic masses, so 



