Atmospheric Electricity III 'Atmospheric Electricity III, July 1900.' Summarizes, 1900, results of experiments on ionization of air in a closed vessel, and, 1902, contains notes for a survey article on atmospheric electricity for Nature. In a later note a calculation is made of the number options to be expected to be found in the free air, assuming q-an[superscript 2]; observations on the radioactivity of rain are discussed. In 1903 plans are considered for an experiment to measure the ionization in a closed vessel sunk in a lake. Various types of electrometer and voltammeter are considered for atmospheric electrical measurements and, in 1906, an unsuccessful attempt to photograph drops formed on ions is described. July 1900