"...nathan stubblefield who stated that earth batteries do not generate electricity: they intercept and receive ground flowing telluric currents. if you wish to find strong telluric currents by this means, place one of your two ground rods into a tree root. the galvanometer should be wired close to this base. the other rod is wired and can be placed in sequentially different spots. readings can literally "pin" the meter, holding it there for weeks" ~an introduction to the mysteries of ground radio, by gerry vassilatos https://borderlandsciences.org/journal/vol/53/n01/Vassilatos_on_Ground_Radio.html