The Royal Danish Academy of Sciences and Letters. Scientia Danica. Series M, Mathematica et physica vol. 2. 2016. 404 pp. Ill. Price DKK 280. 

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 is 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. The invention resulted in a major industrial enterprise 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 – and he ended his career by questioning if argon was really a chemical element.

The present work offers for the first time a comprehensive and contextual account of Thomsen’s life with an emphasis on his contributions to thermochemistry and other branches of science, including his many controversies with foreign chemists. The book presents a full picture of Thomsen and the period in which he lived, meaning not only his science but also his significant contributions to Danish culture and society in general. For example, he served for periods as Rector of the University of Copenhagen and the Polytechnic College and was also a powerful president of the Royal Danish Academy of Sciences and Letters. The picture presented of Thomsen is in some respects novel because it calls attention to his broad interests and work in areas outside experimental thermochemistry. Moreover, based on hitherto unexplored sources the book describes the personal life of the somewhat reclusive scientist.

ISSN 1904-5514 • ISBN 978-87-7304-401-8