A continuous record of the Earth's electric field has been obtained at Poona since September 1930. Since 1935 arrangements were also made to take systematic measurements of the conductivity as well as of the dust, nuclei, and ionic contents of the air simultaneously at some appointed hour. In this preliminary report, all observations cover a period from 1935 to 1937 except those on potential‐gradient which are from September 1930 to November 1937.Poona is a rocky place, situated on a plateau formed on the eastern side of the chain of mountains, called the Western Ghats. Its position is latitude 18° 30′ north, longtitude 73° 53′ east, and its height above mean sea‐level is 1830 feet. It is not an industrial center. During afternoons in summer, a cool sea‐breeze blows from the Arabian Sea and raises a fairly good amount of dust. During the monsoon season (July to September) the sky is almost overcast on most of the days although it rains only occasionally. During September and October there are frequent thunderstorms. During winter (November to February) a strong inversion of temperature occurs almost every evening, followed sometimes by moderate haze or fog in the early morning. Considering the above it will be clear that the number of undisturbed days in a year is very small and observations extending over a long period, therefore, are necessary for the collection of sufficiently reliable data.