Physiological Studies of Monkeys in Electric and Magnetic Fields at ELF Frequencies

The U. S. Navy has proposed a submarine communications system that operates at extremely low frequencies. In this system, a network of synchronized, modulated power sources would drive current loops consisting of long, buried, insulated cables with an earth ground at each end. Current in the cable would produce a magnetic field, and current flowing through the soil would produce a voltage gradient. Available data in the literature were not adequate to assess the biological effects of these fields. Therefore, in a major effort to evaluate these effects, the Navy initiated a project to chronically expose a large number of primates to electric and magnetic fields that were equivalent in waveform but greater in magnitude than those experienced by living organisms, including man, in contact with the soil surface directly above the buried extremely low frequency (ELF) cable.