280 Mr Kenwood on the Electric Currents 



metalliferous deposits are supposed to be synchronous, notwith- 

 standing the lodes of St Just are parallel to the magnetic meri- 

 dian, whilst the cross veins of the same district bear N.E. and 

 S.W. 



Beside this, it must not be forgotten that the magnetic va- 

 riation is a fluctuating quantity; and that, therefore, that which 

 is now coincident with it, was not so some time since, and will 

 not be so a little time hence. 



One rock is assumed to be positive and the other negative, 

 (Mr Fox has not said which he supposes in either state), and 

 thus one ore is deposited in the granite, another in the slate. 



We have seen that in the contiguous mines of Huel Vor, 

 and Great-work, worked on parallel veins, all the tin ore in one 

 mine is in slate, and ail the like ore in the other, is in the gra- 

 nite; also that in Tresavean, the copper-ores are all in the gra- 

 nite* whilst in the parallel veins of United Mines, Wheal Squire, 

 and Ting Tang, they are entirely in slate. 



But we are told by Mr Fox, that different saline solutions, 

 existing " in the rocks, are capable of exciting voltaic action, 

 and giving rise to voltaic currents, even if there were no other 

 cause sufficient to produce them/' (Report of a Lecture deli- 

 vered at Redruth, West Briton, Nov. 4. 1836.) 



I have already stated, that the currents detected in veins, 

 have been confined to their metallic portions ; and that, notwith- 

 standing the same means were applied to the ROCKS, and the 



EARTHY CONTENTS OF THE VEINS, NOT A TRACE OF ELECTRI- 

 CITY HAS YET BEEN FOUND IN EITHER. 



Mr Fox does not allude to the original locality of the metals 

 thus supposed to be deposited by the currents ; this is, however, 

 a very necessary point of inquiry, for they may have been be- 

 yond the reach of electricity. If, however, they are supposed 

 to have been in solution, it is but an obvious application of M. 

 BecquerePs experiments ; where, however, are the solvents now ? 

 If the currents be assumed to have acted IN the Jissures only, 

 what force collected the matter which was not originally con- 

 tained in them ? 



If the force acted beyond the fissures, why were not the ores 

 deposited oufofthem ? 



It may not be out of place to observe, that Mr Fox has 



