German physicist who presented a numerical value for the mechanical equivalent of heat in 1842, based on a horse stirring paper pulp in a cauldron. Although his result was published five years before Joule's, it was Joule who claimed that Mayer's value was nothing but an unsupported hypothesis, who received credit. Mayer attempted suicide, and was confined for a while to a mental institution. Eventually, Tyndall lectured on Mayer's work and tried to obtain the recognition he deserved. Mayer claimed that the "vital chemical process" (now called oxidation) was the ultimate source of energy for a living organism.

Joule, Rumford, Tyndall