An automatic recording method for wireless investigations of the ionosphere

An apparatus for continuous automatic recording of the equivalent height of wireless echoes returned from the ionosphere is described. The Breit and Tuve method is employed, and both the transmitter and the time base at the receiver are synchronized with the a.c. mains. Some specimen records are reproduced and are used to illustrate the normal diurnal variation of equivalent height. Attention is directed to a common abnormal occurrence of increase of ionization in the lower or E region during the hours of darkness, without a corresponding increase in the upper or F region. Reasons are given for supposing that this may be due to the ionizing action of storm clouds, as suggested by C. T. R. Wilson.