Eleetro-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, &c., 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. 
ith 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, &c., nam- 
ed “sossan” 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 
hot coincide in their horizontal direction or underlie ; thus, in this 
fase, 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 
“mon galvanic combinations, and the discovery of electricity in 
Yes seems to complete the resemblance. 
_. He author has been informed by intelligent persons, who have 
“sited some of the mining districts of Mexico, Guatimala and Chili, 
that there is a general resemblance between the veins, elvan courses, 
~*+ I some parts of those countries and our own; and he thinks it 
oY 
