Hess, Victor Franz (Francis)

Hess, Victor Franz (Francis)

(b. Schloss Waldstein, Styria, Austria, 24 June 1883; d. Mount Vernon, New York, 17 December 1964)

physics.

Hess was the son of Vinzenz Hess, forester to the prince of Oettingen-Wallerstein, and Serafine Grossbauer-Waldstätt. He received his early education at the Humanistisches Gymnasium in Graz, from which he graduated in 1901; from 1901 until 1905 he studied mathematics and physics with Leopold von Pfaundler at the university in that city. He took the Ph.D. at the University of Graz in 1906, remaining there to do advanced work with Franz Exner and Egon von Schweidler until 1908. In the latter year Hess became Privatdozent in physics at the Vienna Veterinary College, and in 1910 he was appointed assistant to Stefan Meyer at the newly founded Institute for Radium Research at the university. He was made associate professor in 1911.

When Hess joined Exner and his group in Vienna, ionization in the atmosphere was a principle area for physical research. It was generally known that free air contained electrons, and that if the electrons were removed from air sealed in a container new ones would soon be regenerated, even if the container were shielded in lead. Radioactive pollution of the walls of the container was thought to be responsible for this phenomenon at first; then the effect was attributed to gamma rays originating in the atmosphere and soil. Since the laws governing the diminution of intensity of gamma rays were known, physicists next attempted to identify the origin of those responsible for atmospheric ionization.

In 1910 Theodor Wulf, making experiments on the Eiffel Tower, observed that the ionization of the atmosphere at a height of 300 meters above a gammaray source is greater than that at a distance of 300 horizontal meters. He thus admitted the possibility of extraterrestrial sources for such radiation and suggested that this hypothesis might be confirmed by balloon experiments. A. W. F. E. Gockel, among others, attempted such experiments, but achieved no definite results.

Hess took up the problem stated by Wulf in 1911. He first verified the rate of absorption of gamma rays and then, with the help of the Austrian Academy of Sciences and the Austrian Aeroclub, made ten difficult and daring balloon ascensions, collecting data with improved instrumentation. He reached a height of 5,350 meters, with striking results. He was able to establish that to a height of approximately 150 meters above sea level, radiation decreased according to known laws, while at greater heights radiation increased steadily, following approximately the same laws. He found radiation at 5,000 meters to be several times greater than that at sea level, and also that radiation at all levels was the same night or day, and therefore not the result of the direct rays of the sun. He was thus able to conclude that the radiation he recorded at high altitudes entered the atmosphere from above and was, in fact, of cosmic origin. His results were verified in an extension of his experiments made by W. Kohlhörster in1913—Kohlhörster reached a height of 9,300 meters, and recorded radiation of twelve times that at sea level—but were not acknowledged by other physicists for a number of years. (“Cosmic rays” were so named by R. A. Millikan in 1925.) In 1913 Hess himself equipped the meteorological station on Hoch Obir (2,141 meters) in Carinthia to accommodate further studies of cosmic radiation; these experiments, however, were brought to a halt by World War I.

In 1920 Hess was appointed associate professor at the University of Graz; he soon left this position to accept an offer from the U.S. Radium Corporation in Orange, New York. In the United States Hess served that organization as director of its research laboratory and also acted as consulting physicist for the Department of the Interior (Bureau of Mines). He returned to Graz in 1923 and became full professor there in 1925. After 1927 Hess was able, with the help of a number of Austrian and international organizations, to buy new equipment and to make further investigations of cosmic radiation in several parts of the Alps and the island of Helgoland. In 1931 he was further subsidized by a number of international bodies—in particular, the Rockefeller Foundation—and established a cosmic-ray observatory at an altitude of 2,300 meters on the Hafelekar Spitze, near Innsbruck. He returned to Graz in 1937, but was dismissed from his professorship in 1938, following the Nazi occupation of Austria, because of his strict Roman Catholicism.

Hess returned to the United States, where he became a professor of physics at Fordham University, in New York City, in 1938. He remained at Fordham until his retirement with emeritus status in 1956, becoming a naturalized U.S. citizen in 1944. Hess continued his experiments on the tower of the Empire State Building, at Fordham, and on voyages to South America and in the Pacific. He studied the gamma radiation of rocks, the dust pollution of the atmosphere, and also investigated the refractive indexes of mixtures of liquids. He further concerned himsef with the biomedical problems of workers who handled radium, having himself undergone a thumb amputation in 1934 as a result of an accident with radioactive substances.

Hess’s discovery of cosmic radiation brought him many honors, including membership in the Austrian Academy of Sciences (1933) and the Papal Academy of Sciences; honorary doctorates from Fordham University, Loyola University, and the University of Innsbruck; the Ernst Abbe prize of the Carl Zeiss Foundation (1932); and the Austrian Medal for Science and Arts (1959). The most important honor, however, was the Nobel Prize in physics, which he shared with C.D. Anderson in 1936, on which occasion he lectured on “Unsolved Problems in Physics: Tasks for the Immediate Future in Cosmic Ray Studies.” The discovery of cosmic radiation was one of the keys to the study of elementary particles in general, leading to the discovery of the positron, by Anderson in 1932, and of the μ meson by F. Neddermayer (in 1937).

Hess was married twice, to Mary Bertha Warner (d. 1955) in 1920, and to Elizabeth M. Hoenke in 1955.

BIBLIOGRAPHY

I. Original Works. The Austrian Academy of Sciences has an unpublished list of more than 130 articles by Hess; see also his works listed in Poggendorff.

The most important reports of his discovery of cosmic rays are in Sitzungsberichte der K. Akademie der Wissenschaften in Wien, Mathematisch-naturwissenschaftliche Klasse, 120 (1911), 1575–1585; 121 (1912), 2001–2032; and 122 (1913), 1053–1077, 1481–1486. On his balloon experiments see “Aeronautische Radiumforschung,” in Österreichischer Aero-Club Jahrbuch, 1911 (1912), PP. 102–108; and 1912 (1913), PP. 190–205. See also Die elektrische Leitfähigkeit der Atmosphäre und ihre Ursachen (Brunswick, 1926), trans. as The Electrical Conductivity of the Atmosphere and Its Causes (London, 1928); “Luftelektrizitat,” in Müller-Pouillets Lehrbuch der Physik, 11th ed., V (Brunswick, 1928), 519–661, written with H. Benndorf; “Das Verhalten des Bodens gegen Elektrizität und Radio-aktivität des Bodens,” in Edwin Blanck, ed., Handbuch der Bodenlehre, VI (1930), 375–396; “The Cosmic Ray Observatory in the Hafelekar (2300 Meters),” in Terrestrial Magnetism and Atmospheric Electricity, 37, no. 3 (1932), 399–405; “Die Jonisierungsbilanz der Atmosphäre,” in Ergebnisse der kosmischen Physik, 2 (1933), 95–152; “Ungelöste Probleme in der Physik,” his Nobel Prize lecture, in Les Prix Nobel en 1936 (Stockholm, 1937), PP. 1–3, trans. as “Unsolved Problems in Physics: Tasks for the Immediate Future in Cosmic Ray Studies. Nobel Lecture Dec. 12, 1936,” in Nobel Lectures. Physics (1922–1941) (Amsterdam-London-New York, 1965), PP. 360–362; “The Discovery of Cosmic Radiation,” in Thought (1940), PP. 1–12; Die Weltraumstrahlung und ihre biologischen Wirkungen (Zurich, 1940), written with Jacob Eugster, trans. as Cosmic Radiation and Its Biological Effects (New York, 1949); “Persönliche Erinnerungen aus dem ersten Jahrzehnt des Instituts für Radiumforschung,” in Sitzungsberichte der österreichischen Akademie der Wissenschaften, Mathematisch-naturwissenschaftliche Klasse, 159, sect, IIa (1950), 43–45; and “Work in the USA,” in Österreichische Hochschulzeitung (15 Jan. 1955), p.4.

II. Secondary Literature. On Hess and his work, see the series of articles by Rudolf Steinmaurer, a colleague and collaborator, “Zum 70. Geburtstag,” in Acta physica austriaca, 7 (1953), 209–215 ; –Zum 75. Geburtstag,” ibid., 12 (1959), 121 ff.; “50 Jahre kosmiche Strahlung,” in Physikalische Blätter 18 (1962), 363–369; “Victor F. Hess, der Entdecker der kosmischen Strahlung, 80 Jahre alt,” in Acta physica austriaca, 17 (1964), 113–120; and an obituary notice in Almanach. Österreichische Akademie der Wissenschaften, 116 (1966), 317–328 (with portrait). Other articles are in Österreichs Nobelpreisträger (Vienna, 1965), PP. 117–127; and J. G. Wilson, obituary notice in Nature 207 (1965), 352.

Josef MayerhÖfer