GEOLOGY. 165 



this account the earth probably maintains an oblique 

 position in her course. In accordance with this the 

 earth's axis had first changed, when the metals were 

 generated. According to this also, the sea had rushed in 

 first, when the metallic veins were present. Lastly , in 

 accordance with this, the metals would be generated, 

 when the whole earth was still covered, and the veins 

 filled with water. Unto such conclusions the philosophy 

 of nature can alone conduct us. The cause of a horse- 

 shoe magnet acting more powerfully than any other 

 shaped instrument, resides probably in the form of the 

 earth's crura, 



789. The magnetic meridian varies, however, not 

 only according to places, but times also. This is explica- 

 ble from the mutation of metals under the poles, as well 

 as under the equator and in the temperate zones. Pro- 

 cesses of oxydation and reduction are always occurring, 

 the more too if the water recedes and tracts of land 

 become dry. To this, culture, the clearing of woods, 

 the draining of swamps and probably mining operations 

 themselves conduce.. 



790. It must besides be clear to every one, who has 

 learnt to look upon nature as a whole, that the nume- 

 rous metallic masses of metal upon the earth are not 

 indifferent to the genesis of metal, that they are not 

 foreign to iron ; but that they stand invariably in one 

 relation to it, which can only be magnetic ; for therein 

 only are they metals. 



791. Magnetism is an infinity of tensions spread over 

 the whole earth, of which the tension towards the axis is 

 but the principal, not the sole, tension. The expression 

 hereof is the net of metallic veins. 



792. Every magnetic line consists of an endless num- 

 ber of shifting poles ; for every magnetic line can be but 

 the metatype of terrestrial magnetism. t 



