Notes on radio fade‐out of August 25, 1936

An extensive fade‐out of radio signals in the Western Hemisphere occurred between 18h and 20h GMT, August 25, 1936. R. L. Garrison, Chief of Communications for Pan‐American‐Grace Airways, Inc., reported that communication was disturbed along the entire western coast of South America between these hours. P. D. Boothroyd, operator for the Mackay Radio Telephone and Telegraph Company at Seattle, Washington, sets the time of the fade‐out as from 18h 25m to 19h 20m GMT. Other reports indicate that the fade‐out was experienced from New York to Honolulu.The magnetic and earth‐current records at the Huancayo Magnetic Observatory of the Department of Terrestrial Magnetism of the Carnegie Institution of Washington also exhibited disturbed conditions during the fade‐out according to reports received from O. W. Torreson and W. E. Scott. Reproductions (see Fig. 1) of magnetic record from the Huancayo Observatory and also from that of the Cheltenham Magnetic Observatory of the United States Coast and Geodetic Survey (by courtesy of Director Patton) show departures identical in time with the radio phenomenon. At Huancayo a marked change of some 70 gammas occurred in horizontal intensity, while at Cheltenham a marked change of 6′—equivalent there to about 35 gammas—occurred in declination. There was no marked change in vertical intensity at either station which indicates that the magnetic effects associated with the fade‐out induced currents within the Earth of sufficient magnitude to neutralize the vertical component of the field‐change.