Page:Popular Science Monthly Volume 53.djvu/493

Rh while local auroras are nearer the earth, of small extent, and due to local disturbances.

Telluric currents, passing along telegraphic wires, communicating with the earth at both ends, are visibly and often violently affected



during an aurora, setting electric call-bells ringing, preventing the transmission of messages by throwing the mechanism out of gear, and often proving a source of positive danger. This is not due to, or