Hansteen, Christopher

(b. Christiania [now Oslo], Norway, 26 September 1784; d. Christiania, 15 April 1873)

physics, astronomy.

Hansteen’s father, Johannes Mathias Hansteen, was a customs officer; his mother was Ane Cathrine Treschow, a niece of the philosopher Niels Treschow. In 1814 he married Johanne Cathrine Andrea Borch, a daughter of the head of a famous Danish public school in Sorø In 1802 he began studying law at Copenhagen but, after having been introduced to the fashionable circle around H. C. Oersted, he dropped his law studies in 1806 and devoted the rest of his life to astronomy and physics, particularly geomagnetism. Hansteen became a schoolmaster at Elsinore until 1814, when he was appointed lecturer in applied mathematics and astronomy at the University of Christiania. He became professor in 1816 and retired from this position in 1861.

Geomagnetism had been studied quantitatively since about 1600. Edmond Halley was the first to publish, in 1701, a magnetic chart of the world distribution of the magnetic declination. It was not until near the beginning of the nineteenth century that the intensity of geomagnetism was measured, on the initiative of Jean-Charles Borda and Alexander von Humboldt. Hansteen’s main contribution to science consisted in measurements and theories of geomagnetism. In 1819 he published a magnetic atlas, but at that time observations from large parts of the world were still missing. It was for this reason that Hansteen visited Paris and London in 1819 and Bergen in 1821 and in 1825 traveled round the Gulf of Bothnia to Finland to measure magnetic elements, of which he published the first reliable chart in 1826. In 1828-1830 he led an expedition to Siberia, where he carried out more than 400 measurements,

An announcement in 1811 of a prize to be awarded by the Royal Danish Academy of Sciences for a theory of geomagnetism directed Hansteen to original research in this field. Like Halley in 1683, Hansteen tried in his prize essay to explain the direction and intensity of the magnetic force at any point of the earth by a hypothesis of two magnets of unequal size and strength. He experienced difficulties in carrying out the mathematical consequences of his hypothesis, and it was not until 1839 that an adequate mathematical theory was given by Gauss. It dealt the death blow to Hansteen’s hypothesis, but Gauss admitted having been inspired by Hansteen. In 1815 Hansteen established the first astronomical observatory in Norway, and in 1841 he founded a magnetic observatory. His most important contribution to astronomy was a method for time measurements with simple instruments by observing a star in the vertical plane of the polestar.

In 1817 Hansteen was appointed one of the presidents of the Geodetic Institute, and he played a leading role in the survey of Norway. He had several other public offices, and the elaboration of a new system of standards in Norway was mainly due to his indefatigable work as a member of a government commission in 1819-1824.

Hansteen corresponded with many of the leading scientists of his day; his correspondence with Oersted was particularly extensive and marked by their close friendship and zeal in exchanging scientific results.

BIBLIOGRAPHY

I. Original Works. Hansteen’s most important writings are Untersuchungen über den Magnetismus der Erde I (Christiania, 1819), a rev. version of his prize essay of 1812 (pt. II, never written, was to contain a theory of the aurora borealis and its influence upon geomagnetism); Magnetischer Atlas gehörig zum Magnetismus der Erde (Christiania, 1819); “Isodynamische Linien für der ganze Magnetkraft der Erde,” in Poggendorff’s Annalen der Physik, 9 (1827), 49-66, 229-244; and Resultate magnetischer, astronomischer und meteorologischer Beobachtungen auf einer Reise nach dem östlichen Sibirien in den Jahren 1828-1830 (Christiania, 1863).

Hansteen kept a diary of his expedition to Siberia: Reise-Erinnerungen aus Sibirien (Leipzig, 1854); an enl. Norwegian version, Reise-Erindringer (Christiania, 1859), contains a short autobiography.

Hansteen’s correspondence with H. C. Oersted is in M. C. Harding, ed., Correspondance de H. C. Örsted avec divers savants, I (Copenhagen, 1920), 77-251. An interesting letter from Hansteen to Faraday is in Henry Bence Jones, Life and Letters of Faraday, II (London, 1870), 131.

II. Secondary Literature. A commentary on the letter from Hansteen to Faraday is in R. C. Stauffer, “Persistent Errors Regarding Oersted’s Discovery of Electromagnetism,” in Isis, 44 (1953), 307-310. Biographical information is in Norsk biografisk leksikon, V (Oslo, 1931), 432-448.

Kurt Møller Pedersen