Metalliferous Veins. 16*9 



contents of ike veins, the experiments shewing nothing but the 

 existence of electricity of the present contents of veins, in their 

 present places. ! An experiment should have shewn this, or it is 

 nothing but an assumption ; a probable one, perhaps, but still 

 nothing more. 



Again, it is truly said, that electric currents will pass more 

 readily at right angles, than parallel to the magnetic meridian, 

 and that this explains why the ores are deposited in the east and 

 west veins. But the lodes and cross-courses are all of the same 

 age, and filled at the same periods, says Mr Fox. We have seen 

 that the lodes in St Just bear about north and south. Here, then, 

 we have the same agent, doing the same work, at the same time, 

 in two different modes. For if the more ready transmission in 

 one direction than another, be the cause of the deposit of the ores, 

 why, in one case, is it so formed in harmony with that fact, and 

 in another in direct opposition to it ; and this in both at the 

 same time ? When, too, we have the assumption of synchro- 

 nousfissures (forming a considerable angle with the meridian, and 

 through which the transmission would be far easier) which are 

 not metalliferous. Why, too, is some portion of the quartz de- 

 posited in the east and west, and others in the north and south 

 fissures by the same agent at the same time ? 



I offer these objections respectfully to Mr Fox's consideration, 

 and no one will be more rejoiced than I shall be if he can resolve 

 them. There are many others of equal force, which I reserve, 

 as I fear I have already trespassed too far on your patience. 



Let me add that the fact of parallel lodes in the same district, 

 producing similar ores in different rocks, as of tin in slate of 

 Wheal Vor, and in granite at Great Work, and of copper in the 

 one at Consols, and in the other at Tresavean, does not bear out 

 the conclusion that they were deposited by the agency of electri- 

 city the rocks being in opposite states. If so, which is the po- 

 sitive and which the negative formation ? and why do similar 

 causes, under apparently* like circumstances, produce opposite 

 results ? 



The facts and observations which I have thus attempted to 

 bring together lead me to conclude : 



1. That the phenomena of our metalliferous districts are not 

 consistent with the idea'of the veins having originated in fissures. 



