58 



therefore this general principle may be safely applied to any 

 mining district, be it in America or Europe, and it is so simple 

 that it requires no other aid than the magnetic needle, the know- 

 ledge of the local grain or lamina? of the district, its metalliferous 

 channels and configuration, to enable a person to know where 

 the minerals have been principally deposited, and where scarcity 

 of minerals prevails. This principle, that is, the laws of ter- 

 restrial magnetism, is therefore obviously of vast importance to 

 the practical miner, and the elucidation of the subject to the fur- 

 thest practical extent is the greatest desideratum which now re- 

 mains in the art of mining, since the operations carried on for 

 the discovery of the deposits of ore contained in mineral veins, 

 not only constitute one of the heaviest expenses of mines, but it 

 is the vague and precarious result of these trials which chiefly 

 stamps the proverbial character of hazard and uncertainty which 

 is attached to the pursuit. We therefore trust that the above 

 outline will tend to simplify this interesting subject, and remove 

 that embarrassment and complexity which have hitherto im- 

 peded the progress of this department of geological science. 



CHAPTER IX. 



QUICKSILVER DEPOSITS. 



In the mines of Bavaria this metal exists in a variegated sand- 

 stone resting on slate. It occurs in transverse fractures inter- 

 secting meridional channels of ground, which are nearly perpen- 

 dicular. 



The ores of Cinnabar in the mines of Idria are inclosed in 

 friable talcose rock, interlaminating in small veins in meridional 

 channels. 



In Peru the quicksilver is found like the silver ore, principally 

 in the laminae of the meridional channels. It will therefore be 

 observed that all metals are similarly transmitted or deposited 

 in rocks. 



