HERMANN VON HELMHOLTZ'S DISCOVERY OF FORCE CONSERVATION (ENERGY, GERMANY

Helmholtz is recognized as one of the discoverers of energy conservation. The present study describes the role which the concept of Newtonian force played in the development of Helmholtz's idea of energy conservation. Previous studies have assumed that, by the time of his announcment of energy conservation in 1847, Helmholtz had firmly established the difference between Newtonian force and "force" (Kraft) in the sense of energy. This study shows, however, that well beyond 1847 he continued to perceive a need to clarify the relationship between Newtonian type forces and energy. In addition to connecting energy conservation and conservative Newtonian forces in the 1840s, Helmholtz found that through the energy conservation principle he was able to say definite things about other sorts of forces commonly discussed by his contemporaries, such as chemical affinity and electromotive force. He later saw a need to justify calling such quantities "forces", and by adopting a generalized definition of force he found that they could brought under the same definition as Newtonian force. This study shows that in the 1880s Helmholtz was still actively investigating the implications for physics of the generalized notion of force. In the same period, nearly forty years after his initial discovery of energy conservation, he also arrived at his final formulation of the energy conservation principle. By examining these developments, the present study demonstrates that Helmholtz's essay of 1847 was only the starting point of his investigation of the relationship between force and energy. It finds that it is misleading to portray Helmholtz as a "discoverer" of energy conservation, if by this is meant that what he presented in 1847 was a finished scientific discovery or result which was not subject to further extensive revisions and modifications.