Julius von Mayer

Julius Robert von Mayer (1814 to 1878) was a German physician, chemist and physicist and one of the founders of thermodynamics. Born in Heilbronn in Wurttemberg, the son of a pharmacist, he studied medicine at the University of Tubingen, took his doctorate in 1838 and then sailed as a ship's physician to Jakarta, where he noticed that storm-whipped waves are warmer than a calm sea, which started him thinking about the physical laws of heat. After his return in 1841 he enunciated one of the original statements of the conservation of energy, that energy can be neither created nor destroyed, which is now known as one of the first versions of the first law of thermodynamics. In 1842 he described oxidation as the primary source of energy for any living creature and proposed that plants convert light into chemical energy. His achievements were overlooked, and priority for the discovery of the mechanical equivalent of heat was attributed to James Joule in 1843.