Christopher Hansteen, a Norwegian astronomer, born in Christiania, Sept. 20, 1784, died there in April, 1873. He studied at the university of Copenhagen, and in 1815 was appointed professor of astronomy and mathematics at Christiania. His Magnetismus der Erde (1819) recapitulated all the authentic facts on terrestrial magnetism, from the earliest times; and in his charts of the lines of equal dip, published soon after, he showed that there is but one true magnetic pole in each hemisphere. The results of his investigations of the effects of time and temperature in altering the magnetism of needles are published in his De Mu-tationibus Virgoe Magneticoe (1842). He made numerous observations in the north of Europe, and between 1828 and 1830 travelled in Siberia for the purpose of examining the region of convergence of the needle. On his return he superintended the erection of an observatory in Christiania, of which he became director in 1833. He had charge of the triangulation of Norway, and was a member of the commission for the establishment of a scientific system of measures and weights, for which he furnished the fundamental principles.

In a memoir on the secular change of the dip (Copenhagen, 1855; in French, Brussels, 1865), he argued that the annual diminution of the dip is decreasing, and consequently that a minimum of dip will occur in Europe before the close of this century. His most important works are Resultate magnetischer Beobachtun-gen avf einer Reise nach Sibirien (1863), and "Observations on Magnetic Inclination between the years 1855 and 1864" (Christiania, 1865; in French, Brussels, 1865).