ELECTRICITY IN THE AIR

Radio Record, Volume I, Issue 11, 30 September 1927, Unnumbered Page

ELECTRICITY IN THE AIR

Recent studies of the electrical ° charge of the atmosphere, made by Dr. Bauer of the Carnegie Institution, have shown that the increase with elevation of the normal voltage of the earth’s atmosphere (as compared with the negatively-charged earth) vaties with the time-of year-being greatest — when the earth is nearer the sun, as from October to March, rather than from April to September, when the’. earth is in the more elongated portion. of its orbit. This is independent of the: seasous, which are reversed in the. two hemispheres. At the present time researches are being made into the problem of the solar cycle-that is to’ say, the approximate eleven-year. period during which the prevalence of , sunspots waxes and wanes. A num-., ber of years will be required to answer this question satisfactorily; and then the problem will assume the larger phase of a secular one, which part ofa century may be needed to work out. importance fe Radio. While these considerations do not bear directly upon radio, it is certain that their solution will add data of : importance to the understanding | of. many things connected with radio transmission and reception. While. it is. well known that. the transmissiotv’ of the magnetic waves of radio is affected. by light, it has, become certain that the "potential gradient of atmospheric electricity passes everywliere _ through extreme values during twen-ty-four hours at about the same wniversal times, irrespective of whether the observing station be enveloped by sunshine or darkness." This patential gradient has an average value of about 130 volts per meter of vertical height, being maintained by the great resistivity of the.air. It may be doubled, and almost disappear again during each daily cycle, particularly in in land regions; but whether this electrical charge on atmospheric particles is renewed by solar, or inore distant, radiation had been a matter of discussion. : Atmosphere Charged. The charging from the atmosphere . of an insulated conductor or aerial is a phenomenon observed as early as 1752, long before the production of artificial electromagnetic waves. The fundamental explanation of the source and distribution of the earth’s atmospherie charge, which may bear 4 relation to the asymmetrical position of its permanent magnetic field, may throw much-needed light on the ques‘tion of the propagation and fading of radio waves.