Between two scientific generations: John Herschel’s rejection of the conservation of energy in his 1864 correspondence with William Thomson

It has long been realized by historians that the formulation of the first and X second laws of thermodynamics in the 1840s and 1850s was a complex process (1). What has not been so fully recognized is that the subsequent application of these laws to physical problems was also a complex process. To the formulators of the laws and to contemporaries of their generation there was little problem in applying the laws to physical problems. For example, J. R. Mayer, A. J. Ångström, For.Mem.R.S., J. P.Joule, F. R. S. , G. G. Stokes, F. R. S. , H. Helmholtz, For.Mem.R.S., and W. Thomson, F. R. S. , all of whom were born in the decade following 1814 (2), either formulated the laws of thermodynamics and/or applied them. I have examined elsewhere how some of these scientists (Mayer, Helmholtz and Thomson) applied the first and second laws to refute various mechanisms that had been previously proposed to account for the production of solar energy (3). They replaced them with theories of gravitational attraction whereby the Sun turned dynamical energy into heat energy. I have also examined the application of thermodynamics to theories of the interaction of light and matter that were found not to conform with the principle of the conservation of energy as then understood; Stokes, for example, developed a theory of resonance to explain phenomena such as absorption and fluorescence (4).