Julius Robert von Mayer (1814-1878) was a German physician and physicist who stated the mechanical equivalence of heat in 1842, which is a consequence of the law of conservation of energy. He did so independently of Joule, who received credit for the discovery a few years later. Mayer’s discovery came from his observations of a horse stirring paper pulp in a cauldron. He also is thought to be the first person to describe the chemical process now referred to as oxidation as the primary source of energy for any living organism. As the first person to develop the law of the conservation of energy, Mayer produced one of the most significant achievements in the history of physics.
Julius Robert von Mayer (1814-1878) (University of South Dakota)