Electro-magnetic properties of the mines of CornwalL 141 



Many other facts might, if it were necessary, be accumulated, rel- 

 ative to the position and intersection of veins, as well as the nature 

 and arrangement of their contents, which are calculated to throw en- 

 tire discredit on the various hypotheses which have been invented to 

 account for their origin. But the object is rather to suggest whether 

 the arrangement of veins, Sic, does not argue design, and a probable 

 connection with other phenomena of our globe. 



Metalliferous veins, and those of quartz, &.C., appear to be chan- 

 nels for the circulation of the subterraneous water and vapor ; and the 

 innumerable clay veins or " flucan courses," (as they are termed in 

 Cornwall) which intersect them, and are often found contained in 

 them, being generally impervious to water, prevent their draining the 

 surface of the higher grounds as they otherwise would, and also fa- 

 cilitate the working of mines to a much greater depth than would be 

 practicable without them. 



With respect to their electrical properties, it may be observed, that 

 ores which conduct electricity have generally, in this country at least, 

 non-conducting substances interposed in the veins between the ores 

 and the surface. Thus a brown iron ochre, with quartz, fee, nam- 

 ed " gossan " by the miners, is almost invariably found resting on 

 copper. Sulphuret of zinc occurs sometimes in the same situation, 

 both with regard to copper and lead ; but tin ore, which is a non- 

 conductor, is without either, and is mostly found nearer the surface 

 than copper. 



Tin veins are usually intersected by those of copper when they do 

 not coincide in their horizontal direction or underlie ; thus, in this 

 case, the conducting veins traverse the non-conducting ones. And 

 when two veins of copper meet at opposite angles in descending, 

 they are generally found to be unproductive at and near the place of 

 junction ; but when they unite, proceeding downward in the same 

 direction, but at different angles, they are commonly observed to be 

 enriched. These facts appear curious when regarded in connection 

 with the opposite currents of electricity in veins having opposite dips^ 



Many of the phenomena of the mines bear striking analogies to 

 common galvanic combinations, and the discovery of electricity in 

 veins seems to complete the resemblance. 



The author has been informed by intelligent persons, who have 

 visited some of the raining districts of Mexico, Guatimala and Chili, 

 that there is a general resemblance between the veins, elvan courses, 

 Sic. in some parts of those countries and our own ; and he thinks it 



