Ludvig Lorenz

by Helge Kragh

Published 1 January 2018
Ludvig Valentin Lorenz (1829-1891) was Denmark's first theoretical physicist of international recognition. Although generally considered a secondary figure in the history of science, he contributed importantly to a wide range of subjects ranging from materials science to fundamental theories of optics and electrodynamics.

Apart from his theoretical work he was also a brilliant experimenter who felt as much at home in his laboratory as behind his desk. Today his name is eponymously associated with terms such as the Lorenz gauge, the Lorenz-Lorentz formula, the Lorenz-Mie theory and the Lorenz number.

Julius Thomsen

by Helge Kragh

Published 1 February 2016
Julius Thomsen (1826-1909) was a prominent Danish chemist who acquired fame for his systematic and meticulous measurements of the thermal effects associated with chemical processes. For this work he received numerous honours, among them the Davy Medal from the Royal Society. Apart from his position as one of the founders of classical thermodynamics, he also has a place in the history of chemical technology due to his invention of a method of producing soda from the Greenlandic mineral cryolite.

This invention resulted in a major industrial enterprise which was of great importance to Danish economy. Keenly interested in the electrical sciences, Thomsen constructed a new type of battery which for a while attracted international attention. Last but not least, he made significant contributions to the understanding of the periodic system in terms of the hypothesis of composite atoms. He ended his career by questioning if argon was really a chemical element.

From Quanta to Gravitation

by Helge Kragh

Published 31 January 1970
From Quanta to Gravitation is a full biography of the Danish mathematical physicist Christian Møller (1904-1980) and his important contributions to quantum mechanics, particle physics, and general relativity theory. Because of his life-long association with the Niels Bohr Institute the book is also, more generally, a history of this institute and physics in Copenhagen from about 1930 to 1980. Moreover, Møller interacted with an extensive network of physicists including luminaries such as Niels Bohr, Werner Heisenberg, and Paul Dirac, and for this reason his life and career reflect major developments in international theoretical physics throughout the period. The biography is to a large extent based on archival and other unpublished material. It covers not only Møller's scientific contributions, but also his involvement in the political and organisational aspects of physics.