Dorno, Carl W. M.

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Dorno, Carl W. M.

(b. Königsberg, Prussia [now Kaliningrad, U.S.S.R.], 3 August 1865; d. Davos, Switzerland, 22 April 1942)


The son of Carl Dorno and the former Emma Lehnhard, Dorno came from an old Königsberg merchant family. In 1891 he took over his father’s business; and the following year he married Erna Hundt, from Hamburg, who bore him one daughter. When Dorno was thirty-three years old, he began to study chemistry, physics, political economy, and law at Königsberg University, capping his studies with a doctorate in chemistry in 1904. After his daughter contracted tuberculosis, he moved the family to Davos, an alpine town frequented by consumptives; here he became concerned with determining the factors that made the climate beneficial. In order to conduct research he established a private physical-meteorological observatory, financing it with his personal fortune.

From the beginning Dorno sought the exact measurement and recording of solar and celestial radiation, separately and combined, to determine the total energy and the energies of single spectral regions. For this purpose it was necessary to construct better instruments. Aided by R. Thilenius, Dorno constructed a pyrheliograph, based on older pyrheliometer principles, with a continuous intensity scale that permitted its use in atmospheric investigations, and the Davos frigorimeter. With the information recorded by his new instruments Dorno investigated the annual and diurnal variation of radiation, not only for Davos but also for other places at various latitudes and altitudes.

At high altitudes the intensity of solar radiation is nearly constant; this is the most important factor in the beneficial effects of high-altitude air. On the highest peaks radiation is higher in winter than in summer because of the ellipticity of the earth’s orbit. For the most part water vapor diminishes radiation, especially ultraviolet radiation. Dorno’s investigations on the ultraviolet were so pioneering that the radiation between 2,900 and 3,200 angstrom units is called Dorno’s radiation. He also deduced the concept of biological cooling and was thus the founder of bioclimatology.

Dorno’s daughter died in 1912; but rather than return to Germany, he decided to devote his life to the work he had begun. The loss of his fortune after World War I brought him many difficulties, but the Swiss government took over his observatory and its financial maintenance, permitting him to observe and publish freely as before. In 1926 Dorno retired as director but remained very active in meteorological-physiological studies. Since the mid-1930’s he had suffered from difficulties with his vision, which gradually worsened, so that at last he could no longer continue his scientific work.

Among Dorno’s honors were an honorary M.D. from the University of Basel (1922) and the title of “professor” from the Prussian government.


Dorno’s writings are Studien über Licht und Luft des Hochgebirges (Brunswick, 1911); Dämmerungs- und Ringerschein. 1911–1917 (Brunswick, 1917); Physik der Sonnenund Himmelsstrahlung (Brunswick, 1919); Himmelshelligkeit, Himmelspolarisation und Sonnenintensität, 1911–1918 (Brunswick, 1919); Klimatologie im Dienste der Medizin (Brunswick, 1920); “Fortschritte in Strahlungsmessung (Pyrheliograph),” in Meteorologische Zeitschrift, 39 (1922), 303–323; Meteorologische - physikalische - physiologische Studie Muottas-Muraigl (Davos, 1924); “Über die Verwendbarkeit von Eder’s Graukeilphotometer im meteorologische Dienst,” in Meteorologische Zeitschrift, 42 (1925), 87–97; “Davoser Frigorimeter,” ibid., 45 (1928), 401–421; Assuan, eine meteorologische-physikalische-physiologische Studie (Davos, 1932); and Das Klima von Agra, eine dritte und letzte meteorologische-physiologische Studie (Davos, 1934).

On Dorno, see R. Süring, “Carl Dorno,” in Meteorologische Zeitschrift, 59 (1942), 202–205.

H. C. Freiesleben

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