ELECTRICITY OF MINERAL VEINS. 2X ? 5 



The electricity of mineral veins has attracted much 

 attention, and numerous investigations into the pheno- 

 mena which these metalliferous formations present, have 

 been made from time to time.* 



By inserting into the mass of a copper lode, or vein, in 

 situ, a metallic wire, which shall be connected with a mea- 

 surer of galvanic action, a wire also from the instrument 

 being brought into contact with another lode, an immediate 

 effect is generally produced, showing that a current is 

 traversing through the wires from one lode to the other, 

 and completing the circulation probably over the dark 

 face of the rock in which the fissures forming the 

 mineral veins exist. j- The currents thus detected are 

 often sufficiently active to deflect a magnetic needle 

 powerfully, to produce, slowly, electro-chemical decom- 

 position, and to render a bar of iron magnetic. These 

 currents must not be confounded with the great 

 electrical movements arouud the earth. They are 

 only to be detected in those mineral formations in which 

 there is evidence of chemical action going on, and, the 

 greater the amount of this chemical operation, the more 

 energetic are the electrical currents. J We have, how- 



* On Mineral Veins : by Robert Were Fox, Esq. ; Fourth Re- 

 port of the Royal Cornwall Polytechnic Society. On the Electro- 

 magnetic Properties of Metalliferous Veins in the mines of Cornwall ' 

 by Robert W. Fox, Esq. ; Phil. Trans. 1S30, p. 399. 



f Experiments and Observations on the Electricity of Mineral 

 Vtins : by Robert Hunt and John Phillips; Reports of the Roval 

 Cornwall Polytechnic Society for 1841-42. On the Electricity^ of 

 Mineral Veins : by Mr. John Arthur Phillips ; Ibid., 184.'!. 



I In the lead lodes of Layylas and Frongoch, electrical currents 

 were detected by Mr. Fox, but none in those of South Hold and 

 Milwr, in Flintshire : Cornwall Geological Transactions, vol. ir. 

 In the lead veins of Coldherry and Skeers, in Teasdale, Durham, 

 the currents detected were very feeble : Reports of the Bristol As- 

 sociation, 1838. Von Strombeck could detect no electric currents 

 in the veins worked in the clay slate near Saint Goar, on the 

 Rhine : Archiv. fur Mineralogie. Geognosie, &c., von Dr. C. J. B 

 Karsten, 1833. Professor Rehh, however, obtained very decided 



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