Lord Kelvin's atmospheric electricity measurements

Abstract

Abstract. Lord Kelvin (William Thomson) made important contributions to the study of atmospheric electricity during a brief but productive period from 1859-1861. By 1859 Kelvin had recognised the need for "incessant recording" of atmospheric electrical parameters, and responded by inventing both the water dropper equaliser for measuring the atmospheric potential gradient (PG), and photographic data logging. The water dropper equaliser was widely adopted internationally and is still in use today. Following theoretical considerations of electric field distortion by local topography, Kelvin developed a portable electrometer, using it to investigate the PG on the Scottish island of Arran. During these environmental measurements, Kelvin may have unwittingly detected atmospheric PG changes during solar activity in August/September 1859 associated with the "Carrington event", which is interesting in the context of his later statements that solar magnetic influence on the Earth was impossible. Kelvin's atmospheric electricity work presents an early representative study in quantitative environmental physics, through the application of mathematical principles to an environmental problem, the design and construction of bespoke instrumentation for real world measurements and recognising the limitations of the original theoretical view revealed by experimental work.

Measuring electrical properties of the lower troposphere using enhanced meteorological radiosondes

“…To this electrometer, Kelvin added a sensor able to obtain the air's local electric potential, through charge transfer of water drops falling from an insulated tank. By projecting the electrometer's deflection onto photographic paper, the "water dropper" and electrometer combination made continuous recording of the atmospheric electric field possible (Aplin and Harrison, 2013) 7 .…”

Atmospheric electricity observations at Lerwick Geophysical Observatory

“…This difficulty was removed with the invention of the Kelvin water dropper equaliser in 1859, which equalised the potential with the air through using a fine mist of water supplied from a header tank. By keeping the tank filled with water, continuous measurements of PG became possible, and permanent recordings of the variations obtained were made by projecting the electrometer's deflection onto photographic recording paper (Aplin and Harrison, 2013). Following the naming convention for other meteorological self-registering (or "autographic") instruments, a continuous recording device for the PG was known as an "electrograph" or, more specifically when a water dropper equaliser was used, the "Kelvin electrograph".…”

Application of Corona Charge Deposition Technique in Thin Film Industry

“…The wide range of applications includes analysis and improvement of device properties [24] [25] [26] [27], understanding the electrical properties of insulators and other materials [25] [26] [27] [28], failure analysis of ICs [29] and noncontact metrology [19] [20] [21] [22].…”