What Was Discovered in the 1840s?

This chapter analyzes the texts of the authors considered to be the discoverers of energy: Robert Mayer, James Joule, Ludvig Colding and Hermann von Helmholtz. Although they have in common that they defend a thesis on heat that was contrary to the science of the time, they differ in their interpretation of the experiments, namely on the nature of heat, and in the theories they developed. This diversity was mitigated when they began to appear as having discovered the same thing. The present analysis aims to provide a sharper idea of the authors by focusing on the texts of each of them and making a systematic distinction between experiments and interpretations. After that, some of their theses will be compared with each other and with the current principle of conservation of energy.