manager of the city astronomical observatory from the same year and co-director of the Norwegian Mapping Authority (then known as Norges Geografiske Oppmåling) from 1817. In 1819 he published a volume of researches on terrestrial magnetism, which was translated into German under the title of Untersuchungen über den Magnetismus der Erde, with a supplement containing Beobachtungen der Abweichung und Neigung der Magnetnadel and an atlas. By the rules there framed for the observation of magnetical phenomena Hansteen hoped to accumulate analyses for determining the number and position of the magnetic poles of the Earth. In 1822 he co-founded Norway's first journal on natural sciences, Magazin for Naturvidenskaberne. He sat as editor-in-chief for eight years. In the course of his research he travelled over Finland and the greater part of his own country; and from 1828 to 1830 he undertook, in company with Georg Adolf Erman and with the co-operation of Russia, a government-funded mission to Western Siberia. A narrative of the expedition soon appeared (Reise-Erinnerungen aus Siberien, 1854; Souvenirs d’un voyage en Sibérie, 1857); but the chief work was not issued until 1863 (Resultate magnetischer Beobachtungen). He did not conclude on the issue at hand, but his work was later completed by Carl Friedrich Gauss. Shortly after the return of the mission, in 1833 Hansteen moved with his family into the observatory, which was created from drawings by the architect Christian Heinrich Grosch. A magnetic observatory was added in 1839. From 1835 to 1838 he published textbooks on geometry and mechanics, largely a reaction to his former research assistant Bernt Michael Holmboe's textbooks. Compared to Holmboe's method of teaching, Hansteen's books were more practically oriented. After Holmboe wrote a review of the first textbook for the newspaper Morgenbladet, in which he advised schools not to use it, a public debate followed, with contributions from other mathematicians. It has been claimed that this was the first debate on the subject of school textbooks in Norway. Holmboe's textbooks proved more lasting, with Hansteen's textbook not being reprinted. In 1842 Hansteen wrote his Disquisitiones de mutationibus, quas patitur momentum acus magneticae. He also contributed various papers to different scientific journals, especially Magazin for Naturvidenskaberne. Hansteen was a member of the Royal Norwegian Society of Sciences and Letters from 1818 and of the Norwegian Academy of Science and Letters from 1857, as well as several learned societies in other countries, including the Royal Swedish