Kemikeren Julius Thomsen (1826-1909) hører til de mest betydningsfulde naturforskere ikke bare i dansk, men også i international videnskabshistorie. Han skabte sin berømmelse på præcise og systematiske målinger af reaktionsvarmen fra kemiske processer, et arbejde, der sikrede ham talrige priser og hædersbevisninger. Udover dette pionerarbejde i termokemien har han også en plads i teknologihistorien. Det skyldes især hans opfindelse af en metode til at fremstille soda ud fra det grønlandske mineral kryolit. Opfindelsen resulterede i et industrieventyr, der blev af stor betydning for den danske statsøkonomi. Selv om han især arbejdede i laboratoriet, var han også optaget af teoretiske problemer, bl.a. spekulationer om atomteoriens kemiske betydning. Hans overvejelser om grundstoffernes periodiske system og det sammensatte atom viste sig at være profetiske.
Bogen giver for første gang en omfattende og detaljeret fremstilling af Julius Thomsens liv og virke med fokus på hans videnskabelige bidrag og de mange kontroverser, han havde med udenlandske kemikere. Men selv om fokus er på hans videnskab, giver bogen også et billede af den tid, han levede i, og det samfund og den kultur, han var en del af. Ikke blot var han en af landets mest prominente naturforskere, han var også rektor for både universitetet og Den polytekniske Læreanstalt, og gennem en længere periode var han en magtfuld præsident for Videnskabernes Selskab. Hans liv var uadskilleligt fra hans arbejde i laboratoriet, men han havde dog også et liv udenfor. På grundlag af hans brevveksling og andet kildemateriale på Det kongelige Bibliotek beskriver bogen både kemikeren Thomsen og mennesket Thomsen.
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.
