Entropy as thermal charge: an application of bond graphs inspired by Carnot and his cycle

A precursor of Lord Kelvin (1824–1907), he also discovered towards the end of his life the first law of thermodynamics, that of the conservation of energy, as shown in his posthumous articles published in 1878. This principle was rediscovered and stated in 1842 by Mayer (1814–1878) following in the footsteps of Clapeyron who had already published his ‘Memoir on the Motive Power of Heat’ in 1834, in which he developed the ideas of Carnot who had died 2 years before.