XXV. On the electro-magnetic properties of metalliferous veins in the mines of Cornwall

Abstract

In one of my communications to the Cornwall Geological Society on the high temperature of the interior of the earth, I ventured to express a belief that mineral veins, and the internal heat, are connected with electrical action. This opinion, founded as it was on the curious arrangement of the veins, &c. in pri­mitive rocks, I have had the satisfaction to find confirmed by experiments made in some of the mines of Cornwall; and, I doubt not that the existence of electricity in metalliferous veins similarly circumstanced, and capable of con­ducting it, will prove to be as universal a fact, as the progressive increase of temperature under the earth’s surface is now admitted to be, much as my conclusions on this point were at one time controverted. In my first experiment I did not succeed in detecting any electricity; but in my second I had the gratification to observe considerable electrical action.