Conservation and Innovation : Helmholtz's Struggle with Energy ...

had already been achieved in the Bericht. What is new and specific of the
Erhaltung is the application of the theoretical framework of tension and living
forces to the mechanical theory of heat. This again is done in a purely conceptual
and qualitative way, without mathematical formulation: free heat will now be
interpreted as the quantity of living force of thermal movement and latent heat as
the quantity of tension forces, namely elastic forces of atoms. Helmholtz quoted
Ampère while making an attempt at clarifying the atomistic view of nature and
the way in which atomic movements can explain radiation and conduction. But
the whole subject is highly speculative and Helmholtz is satisfied with "the
possibility that thermal phenomena be conceived as motions" 174. In fact in this
case the conservation of force "could be verified" whenever conservation of
caloric substance was supposed to hold.
In my view, Helmholtz's cautiousness is completely justified. It is not due to a
lack of conceptual clarity, but to the awareness of the lack of empirical
corroboration. In my opinion, the doubt raised by Helm whether, at this point of
the Erhaltung , Helmholtz was still "uncertain and vacillating" on the validity of
the impossibility of the perpetuum mobile outside mechanics 175 is to be rejected.
Despite being qualitative, Helmholtz's conceptual scheme is wide- ranging. To
explicitly conceive atoms as possessing not only living forces but also tension
forces is a bold step forward and the analogy with free and latent heat seems very
well defined. It allowed in fact an easy reinterpretation of previous knowledge in
the new terms.
The reinterpretation of the heat produced in chemical processes follows: Hesse's
law "partially verified also by experience" had been deduced from the caloric
theory. It asserts that "the heat developed in the production of a chemical
compound is independent of the order and the intermediate steps of the
process" 176. The law, as shown in the "Bericht", is in agreement with the forceequivalent
hypothesis (correlation principle), but here Helmholtz showed that it
can be interpreted in terms of the new concepts of living and tension forces: the
heat produced is now considered a living force, generated by the chemical forces
174 Helmholtz Erhaltung P.31.
175 Helm hinted that Helmholtz's cautiousness in the application of his second root
(central forces and mechanical hypothesis) to thermal phenomena implies that he had doubts
on the first one (impossibility of perpetual motion) as well, and thus on the whole conservation
problem. G.Helm Energetik P.44
176 Helmholtz Erhaltung P.32.