Carl Friedrich Gauss und Christopher Hansteen

As Wikipedia will tell you, “Christopher Hansteen (26 September 1784–11 April 1873) was a Norwegian geophysicist, astronomer and physicist, best known for his mapping of Earth's magnetic field.” And, as all mathematicians know, Carl Friedrich Gauss (1777–1855) was “the prince of mathematicians” (though, as Wikipedia also tells us, the Latin tag is actually princeps mathematicorum, i.e., “the foremost mathematician”). Of course, Gauss was far more than a mathematician. At Göttingen, he was director of the observatory, not a professor of mathematics, and his work spans astronomy, mathematics, physics, and even geography.

Gauss’s main collaborator when he was working on physics was Wilhelm Weber, who came to Göttingen in 1831. Beginning in 1832, Gauss and Weber started working on the physics of magnetism, and in particular on the Earth’s magnetic field. It is no accident, then, that the correspondence collected here begins in 1832.

The letters proper begin on page 136 of this book. They are preceded by several context-setting chapters, mostly on Hansteen rather than on Gauss, but including an analysis of their interaction. The edition of the letters begins with a letter from Gauss to the astronomer Heinrich Christian Schumacher, who had been in contact with Hansteen from 1816. Then follow 17 letters between Hansteen and Gauss. These are, of course, annotated. More importantly, they are indexed. This is therefore a fundamental resource for historians.

The book is beautifully produced, even including a section with color reproductions of portraits of Gauss and Hansteen together with several maps of the Earth’s magnetic field. But the letters are rightly at the center.

Fernando Q. Gouvêa is Carter Professor of Mathematics at Colby College and Editor of MAA Reviews.