Editing Caloric theory (section)

==Later developments==
In 1798, [[Benjamin Thompson|Count Rumford]] published "[[An Inquiry Concerning the Source of the Heat Which Is Excited by Friction]]", a report on his investigation of the heat produced while [[manufacturing]] [[cannon]]s. He had found that [[Boring (manufacturing)|boring]] a cannon repeatedly does not result in a loss of its ability to produce heat, and therefore no loss of '''caloric'''. This suggested that '''caloric''' could not be a conserved "substance", though the experimental uncertainties in his experiment were widely debated.

His results were not seen as a "threat" to caloric theory at the time, as this theory was considered to be equivalent to the alternative [[kinetic theory of gases|kinetic theory]].<ref>See for example [[Antoine Lavoisier|Lavoisier, A.-L. de]] (1783). ''Mémoire sur la chaleur, lu à l'Académie royale des sciences, le 28 juin 1783, par MM. Lavoisier et de La Place''.</ref> In fact, to some of his contemporaries, the results added to the understanding of caloric theory.
[[File:Joule's Apparatus (Harper's Scan).png|thumb|Joule's apparatus for measuring the [[mechanical equivalent of heat]].]]
Rumford's experiment inspired the work of [[James Prescott Joule]] and others towards the middle of the 19th century. In 1850, [[Rudolf Clausius]] published a paper showing that the two theories were indeed compatible, as long as the calorists' principle of the conservation of heat was replaced by a principle of [[conservation of energy]]. Although compatible however, the theories differ significantly in their implications. In modern thermodynamics, heat is usually a transfer of [[kinetic energy]] of particles (atoms, molecules) from a hotter to a colder substance.

In later combination with the law of energy conservation, the caloric theory still provides a valuable analogy for some aspects of heat, for example, the emergence of [[Laplace's equation]] and [[Poisson's equation]] in the problems of spatial distribution of heat and temperature.{{Cn|date=August 2023}}