Kalinowski was not a man of modest plans. Working at the Physics Laboratory of the Museum of Industry and Agriculture in Warsaw, he had been inspired by the Carnegie Institution of Washington’s international campaign to map Earth’s magnetic field, and he resolved that Poland needed its own magnetic observatory. In 1911 he published a leaflet titled On an urgent scientific matter, appealing to the Polish public to fund the venture. The Mianowski Fund became the principal benefactor, joined by other organisations and even Kalinowski himself. Buildings rose between 1913 and 1915 at a plot he had bought near the Świder resort, modelled closely on the internationally respected observatories at Pavlovsk, Potsdam and Seddin, which Kalinowski and his architect Łukasz Wolski had visited in person. The site opened officially on 1 January 1921, after delays caused by the First World War and the Polish-Soviet war.

Magnetism, however, was only the beginning. Kalinowski later wrote in a national report to the International Association of Terrestrial Magnetism and Electricity that once the magnetic work was organised, an idea came to him to expand into other branches of the physics of the Earth, gradually transforming the Magnetic Observatory into a Geophysical Observatory. He was also pragmatically worried: the electrification of railways could one day disturb magnetic readings and threaten the observatory’s very existence, which was partly why he had chosen the quiet Świder location in the first place. Atmospheric electricity offered a natural second pillar. The Carnegie Institution’s Department of Terrestrial Magnetism funded numerous atmospheric electric observations worldwide, a practice originally encouraged by the pioneering physicists Julius Elster and Hans Geitel, and several magnetic observatories, including Kakioka in Japan, with which Świder exchanged publications, carried out both kinds of work simultaneously.

The scientific climate favoured the move. At the turn of the century, Professor August Witkowski had already mastered the measurement of the atmospheric potential gradient in Zakopane using a radioactive collector method, and Professor Władysław Smosarski measured air conductivity and potential gradient at Golęcin from 1923 to 1929. More significantly, the International Union of Geodesy and Geophysics, founded in 1919, passed a resolution at its Rome assembly in 1922, reaffirmed in Madrid in 1924, declaring it desirable that every country operate at least one observatory making systematic, internationally comparable atmospheric-electric observations of potential gradient, air-earth currents, conductivity and ion counts. Kalinowski, ambitious and persistent, took note. What he needed was money, and it arrived in the form of a grant from the National Culture Fund.

A pavilion dedicated to atmospheric electricity had already been built at the site in 1925, though damp forced a refurbishment and the start of measurements slipped from the promised 1925 to 1928. The decisive subsidy of 30,000 zloty in June 1928 allowed the purchase of three Benndorf electrometers from L. Castagna, radioactive collectors, insulators and three calomel batteries. In total the observatory acquired four Benndorf electrometers, a Wulf electrometer, two other electrometers, an ionisation chamber, an Ebert ion counter and a Spindler & Hoyer Gerdien tube apparatus. Dr Henryk Jędrzejowski, a physicist newly hired in 1928, installed the first potential gradient measurements, and after his departure and that of his successor Antoni Liliental, the work passed to the observatory’s permanent staff. Continuous recording with two radioactive collectors and two Benndorf electrometers began on 1 October 1929.

The technical set-up was elegant in its simplicity and demanding in its upkeep. The Benndorf electrometer, a quadrant electrometer with mechanical registration, was a workhorse of early atmospheric electricity stations from Lerwick in Scotland to Kakioka in Japan. Its vertical needle, connected through a wire to the potential being measured, moved between charged plate electrodes, and a pen attached to the needle traced the varying voltage onto a paper sheet driven by clockwork, producing a continuous chart called an electrogram. Outside, two copper wires stretched 30 metres from the pavilion to a wooden column, insulated with amber brackets and tensioned by 10-kilogram weights so that their height above the cleared ground remained constant regardless of temperature. At the midpoint of each wire, 2.25 metres above the ground, hung a radioactive collector coated with ionium, a decay product of thorium whose emissions ionised the surrounding air and allowed the probe to rapidly acquire the local atmospheric potential.

Inside the single-room building, three metres long and vaulted to a height of over three metres, the two Benndorf electrometers hung on wall brackets, one set to lower sensitivity and one to higher, their quadrants charged by calomel batteries to carefully chosen voltages. Earthing was achieved through a zinc sheet about a square metre in area, buried two metres deep in moist soil. Maintenance was relentless: electrometer sensitivity was checked every two weeks, batteries monitored with a Weston voltmeter, a zero line marked at the beginning and end of each daily electrogram, and insulation inspected twice a day. The most fragile element was the isolation of the collectors and the stability of the potential delivered to the measuring devices, a weakness that would later cast doubt on some of the data.

One problem proved especially stubborn. The observatory site was surrounded by trees, and nearby vegetation distorts the atmospheric electric field, so raw readings cannot be compared directly between stations. The standard practice is to express the potential gradient as if measured above a flat open plane, which requires a site-specific reduction factor. Low trees stood only 10 to 15 metres from the collectors, with taller trees farther away. Measurements taken on genuinely flat terrain at a greater distance were judged unreliable, so Kalinowski’s team adopted an ingenious alternative: they built a plaster model of the terrain surrounding the measurement site and calculated the distortion of the electric potential on the miniature landscape. Ewa Kalinowska, the founder’s younger daughter and an experimental physics student, was probably involved in this pre-war work, and Kalinowski later credited her with voluntarily leading the observatory’s atmospheric electricity section.

The war destroyed almost everything the decade had produced. The materials summarising nine years of results, considered ready for publication, had been moved temporarily to Kalinowski’s home office in Warsaw, and the manuscripts, including some original recording notes, perished in the early Luftwaffe bombings of the city in September 1939. The plaster terrain model, which offered an independent route to the reduction coefficient, was destroyed at the Warsaw University of Technology. The observatory buildings themselves survived relatively unscathed and magnetic work continued in dangerous circumstances, but the potential gradient recordings stopped because tracing paper for the electrometers became impossible or too expensive to buy. In a 1939 report to the international association, written shortly before the catastrophe, Kalinowski lamented that limited resources had prevented the broadened programme promised by the observatory’s new Geophysical name, and that the installations for recording air conductivity and precipitation electricity had made no progress.

Yet the story did not end in 1939. Atmospheric electric work resumed at Świder in 1948 in a transformed Poland, and after the Second World War the observatory, renamed the Stanisław Kalinowski Geophysical Observatory in 1946, became primarily an atmospheric electricity station with a broad remit spanning meteorology, air pollution and air radioactivity. When magnetic observations moved to a new observatory at Belsk in 1976, the atmospheric programme Kalinowski had seeded became the institution’s core identity. Post-war analysis by Ewa Kalinowska-Widomska finally quantified the pre-war data: for undisturbed days in 1930, the mean potential gradient was about 101 volts per metre, with seasonal averages ranging from 136 volts per metre in winter to 58 in autumn, the latter likely depressed by insulation problems. She also confirmed Kalinowski’s qualitative finding of a double daily wave in summer and a single wave in winter, matching most northern hemisphere stations. One Benndorf electrometer and the Gerdien tube apparatus still survive at the observatory, displayed in a small museum, and in 2024 the atmospheric electricity building was added to Poland’s national heritage register, a quiet monument to a decade of measurements that war could interrupt but not erase.

Subject of Research: Historical atmospheric electricity observations of the atmospheric potential gradient at the Świder Geophysical Observatory, Poland, 1929–1939

Article Title: The first decade (1929–1939) of atmospheric electricity observations at Świder Geophysical Observatory

Article References: Odzimek, A. (2026). The first decade (1929–1939) of atmospheric electricity observations at Świder Geophysical Observatory. History of Geo- and Space Sciences, 17(1), 13-24. https://doi.org/10.5194/hgss-17-13-2026

Image Credits: AI Generated

DOI: 10.5194/hgss-17-13-2026

Keywords: atmospheric electricity, potential gradient, Świder Observatory, Benndorf electrometer, Stanisław Kalinowski, geophysical observatories, history of geophysics, radioactive collectors, Poland, World War II, geomagnetism, scientific heritage