This paper examines how ionospheric physics emerged as a research speciality in Britain, Germany, and the United States in the first 4 decades of the 20th century. It argues that the formation of this discipline can be viewed as the confluence of four deep-rooted traditions in which scientists and engineers transformed, from within, research areas connected to radio wave propagation and geomagnetism.
With countless reports, few physical records, and no theory consensus, ball lightning remains an unsolved problem in atmospheric physics; 41 qualified observation abstracts (1868–2020) from eight countries are presented by a case investigator. Some were related to mountain, power line, aeroplane; two had medical effects. Six influential cases are added. High-quality report data stimulate further fieldwork and theories of the phenomenon. Scientific readers are invited to share unreported events.