HANSTEEN, CHRISTOPHER astronomer and physicist, was born at Christiania (Oslo) on Sept. 26, 1784. From the cathedral school he went to the uni versity of Copenhagen, where he studied mathematics. In 1807 he began the inquiries in terrestrial magnetism with which his name is especially associated. He took in 1812 the prize of the Danish Royal Academy of Sciences for his reply to a question on the magnetic axes. Appointed lecturer in 1814, he was in 1816 raised to the chair of astronomy and applied mathematics in the university of Christiania. In 1819 he published a volume of re searches on terrestrial magnetism, Untersuchungen caber den Magnetismus der Erde, with a supplement containing Beobach tungen der Abweichung and Neigung der Magnetnadel and an atlas. Hansteen wished to determine the number and position of the earth's magnetic poles and to obtain observations for this purpose he travelled over Finland and the greater part of his own country; and in 1828-3o he undertook, in company with G. A. Erman, and with the co-operation of Russia, a government mis sion to western Siberia. A narrative of the expedition soon appeared (Reise-Erinnerungen aus Sibirien, 1854 ; Souvenirs d'un voyage en Siberie, 1857) ; but the chief work was not issued till 1863 (Resultate magnetischer Beobachtungen, etc.). In an observatory was erected in the park of Christiania and Han steen was appointed director. On his representation a magnetic observatory was added in 1839. He wrote (1842) Disquisitiones de mutationibus quas patitur momentum aces magneticae, and contributed various papers to scientific journals, especially the Magazin for Naturvidenskarberne, of which he became joint editor in 1823. He superintended the trigonometrical and topo graphical survey of Norway, begun in 1837. In 1861 he retired from active work, but still pursued his studies, his Observations de l'inclination magnetique and Sur les variations seculaires du magnetisme appearing in 1865. He died on April II, See Proc. of Amer. Acad. •